10-Q

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, DC 20549

 ____________________________________________________________________________

FORM 10-Q

 ____________________________________________________________________________

(Mark One)

x	Quarterly report pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934
	For the quarterly period ended September 30, 2015

or

o	Transition report pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934
	For the transition period from ______  to  ______

Commission File Number 000-23441

 ____________________________________________________________________________

POWER INTEGRATIONS, INC.

(Exact name of registrant as specified in its charter)

 ____________________________________________________________________________

DELAWARE	94-3065014
(State or other jurisdiction of Incorporation or organization)	(I.R.S. Employer Identification No.)

5245 Hellyer Avenue, San Jose, California, 95138

(Address of principal executive offices) (Zip code)

(408) 414-9200

(Registrant’s telephone number, including area code)

 ____________________________________________________________________________

Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days.    YES  x    NO o

Indicate by check mark whether the registrant submitted electronically and posted on its corporate Web site, if any, every Interactive Data File required to be submitted and posted pursuant to Rule 405 of Regulation S-T (§ 232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit and post such files).    YES  x   NO  o

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer or a smaller reporting company. See the definitions of “large accelerated filer,” “accelerated filer” and “smaller reporting company” in Rule 12b-2 of the Exchange Act:

Large accelerated filer  x	Accelerated filer  o
Non-accelerated filer    o (Do not check if  a smaller reporting company)	Smaller reporting company  o

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act).    YES  o    NO  x

Indicate the number of shares outstanding of each of the issuer’s classes of common stock, as of the latest practicable date.

Class	Shares Outstanding at October 16, 2015
Common Stock, $0.001 par value	28,430,305

POWER INTEGRATIONS, INC.

TABLE OF CONTENTS

		Page
PART I. FINANCIAL INFORMATION
Item 1.	Financial Statements
	Condensed Consolidated Balance Sheets as of September 30, 2015 and December 31, 2014	4
	Condensed Consolidated Statements of Income for the three and nine months ended September 30, 2015 and 2014	5
	Condensed Consolidated Statements of Comprehensive Income for the three and nine months ended September 30, 2015 and 2014	6
	Condensed Consolidated Statements of Cash Flows for the nine months ended September 30, 2015 and 2014	7
	Notes to Unaudited Condensed Consolidated Financial Statements	8
Item 2.	Management’s Discussion and Analysis of Financial Condition and Results of Operations	31
Item 3.	Quantitative and Qualitative Disclosures About Market Risk	41
Item 4.	Controls and Procedures	42
PART II. OTHER INFORMATION
Item 1.	Legal Proceedings	43
Item 1A.	Risk Factors	43
Item 2.	Unregistered Sales of Equity Securities and Use of Proceeds	49
Item 6.	Exhibits	49
SIGNATURES		50

2

Cautionary Note Regarding Forward-Looking Statements

This Quarterly Report on Form 10-Q includes a number of forward-looking statements that involve many risks and uncertainties. Forward-looking statements are identified by the use of the words “would”, “could”, “will”, “may”, “expect”, “believe”, “should”, “anticipate”, “if”, “future”, “intend”, “plan”, “estimate”, “potential”, “target”, “seek” or “continue” and similar words and phrases, including the negatives of these terms, or other variations of these terms, that denote future events. These statements reflect our current views with respect to future events and our potential financial performance and are subject to risks and uncertainties that could cause our actual results and financial position to differ materially and adversely from what is projected or implied in any forward-looking statements included in this Form 10-Q. These factors include, but are not limited to, the risks described under Item 1A of Part II — “Risk Factors,” Item 2 of Part I — “Management’s Discussion and Analysis of Financial Condition and Results of Operations” and elsewhere in this Quarterly Report on Form 10-Q, including, but not limited to: our quarterly operating results are volatile and difficult to predict, and if we fail to meet the expectations of public market analysts or investors, the market price of our common stock may decrease significantly; if demand for our products declines in our major end markets, our net revenues will decrease; intense competition in the high-voltage power supply industry may lead to a decrease in our average selling price and reduced sales volume of our products; if we are unable to adequately protect or enforce our intellectual property rights, we could lose market share, incur costly litigation expenses, suffer incremental price erosion or lose valuable assets, any of which could harm our operations and negatively impact our profitability; if we do not prevail in our litigation, we will have expended significant financial resources, potentially without any benefit, and may also suffer the loss of rights to use some technologies; and our international sales activities account for a substantial portion of our net revenues, which subjects us to substantial risks. We make these forward-looking statements based upon information available on the date of this Form 10-Q, and we have no obligation (and expressly disclaim any obligation) to update or alter any forward-looking statements, whether as a result of new information or otherwise except as otherwise required by securities regulations.

3

PART I. FINANCIAL INFORMATION

ITEM 1. FINANCIAL STATEMENTS

POWER INTEGRATIONS, INC.

CONDENSED CONSOLIDATED BALANCE SHEETS

(Unaudited)

(In thousands)	September 30, 2015			December 31, 2014
ASSETS
CURRENT ASSETS:
Cash and cash equivalents	$	59,735		$	60,708
Short-term marketable securities	91,222			114,575
Accounts receivable, net of allowances of $319 and $191 in 2015 and 2014, respectively (Note 2)	11,061			10,186
Inventories	55,439			64,025
Deferred tax assets	75			39
Prepaid expenses and other current assets	5,780			16,379
Total current assets	223,312			265,912
PROPERTY AND EQUIPMENT, net	102,223			95,823
INTANGIBLE ASSETS, net	39,957			35,524
GOODWILL	91,849			80,599
DEFERRED TAX ASSETS	10,647			11,562
OTHER ASSETS	5,502			4,243
Total assets	$	473,490		$	493,663
LIABILITIES AND STOCKHOLDERS’ EQUITY
CURRENT LIABILITIES:
Accounts payable	$	23,370		$	21,980
Accrued payroll and related expenses	8,203			9,071
Taxes payable	2,022			2,963
Deferred tax liabilities	1,985			2,193
Deferred income on sales to distributors	16,464			15,223
Other accrued liabilities	3,182			3,730
Total current liabilities	55,226			55,160
LONG-TERM INCOME TAXES PAYABLE	746			743
DEFERRED TAX LIABILITIES	3,752			4,272
OTHER LIABILITIES	2,569			2,812
Total liabilities	62,293			62,987
COMMITMENTS AND CONTINGENCIES (Notes 9, 11, 12 and 15)
STOCKHOLDERS’ EQUITY:
Common stock	28			29
Additional paid-in capital	136,422			171,938
Accumulated other comprehensive loss	(1,043		)	(1,136		)
Retained earnings	275,790			259,845
Total stockholders’ equity	411,197			430,676
Total liabilities and stockholders’ equity	$	473,490		$	493,663

The accompanying notes are an integral part of these unaudited condensed consolidated financial statements.

4

POWER INTEGRATIONS, INC.

CONDENSED CONSOLIDATED STATEMENTS OF INCOME

(Unaudited)

	Three Months Ended				Nine Months Ended
	September 30,				September 30,
(In thousands, except per share amounts)	2015		2014		2015		2014
NET REVENUES	$	88,878	$	90,144	$	256,700	$	262,202
COST OF REVENUES	44,717		41,092		126,229		118,437
GROSS PROFIT	44,161		49,052		130,471		143,765
OPERATING EXPENSES:
Research and development	13,888		13,458		43,693		41,314
Sales and marketing	11,129		11,564		35,701		35,906
General and administrative	7,361		7,155		23,133		22,614
Total operating expenses	32,378		32,177		102,527		99,834
INCOME FROM OPERATIONS	11,783		16,875		27,944		43,931
OTHER INCOME
Other income, net	428		381		219		836
Total other income	428		381		219		836
INCOME BEFORE INCOME TAXES	12,211		17,256		28,163		44,767
PROVISION FOR (BENEFIT FROM) INCOME TAXES	698		1,145		1,717		(423		)
NET INCOME	$	11,513	$	16,111	$	26,446	$	45,190
EARNINGS PER SHARE:
Basic	$	0.40	$	0.54	$	0.91	$	1.50
Diluted	$	0.39	$	0.52	$	0.89	$	1.46
SHARES USED IN PER SHARE CALCULATION:
Basic	28,855		30,013		29,175		30,186
Diluted	29,298		30,757		29,856		31,053

The accompanying notes are an integral part of these unaudited condensed consolidated financial statements.

5

POWER INTEGRATIONS, INC.

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME

(Unaudited)

	Three Months Ended					Nine Months Ended
	September 30,					September 30,
(In thousands)	2015		2014			2015			2014
NET INCOME	$	11,513	$	16,111		$	26,446		$	45,190
Other comprehensive income, net of tax:
Foreign currency translation adjustments, net of $0 tax in the three and nine months ended September 30, 2015 and 2014 (Note 2)	40		(53		)	18			(42		)
Unrealized gain (loss) on marketable securities, net of $0 tax in the three and nine months ended September 30, 2015 and 2014 (Note 2)	20		(246		)	(17		)	(7		)
Amortization of defined benefit pension items, net of tax of $18 and $26 in the three and nine months ended September 30, 2015, respectively and $4 and $12 in the three and nine months ended September 30, 2014, respectively (Note 2)	64		15			92			45
Total other comprehensive income (loss)	124		(284		)	93			(4		)
TOTAL COMPREHENSIVE INCOME	$	11,637	$	15,827		$	26,539		$	45,186

The accompanying notes are an integral part of these unaudited condensed consolidated financial statements.

6

POWER INTEGRATIONS, INC.

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS

(Unaudited)

	Nine Months Ended
	September 30,
(In thousands)	2015			2014
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$	26,446		$	45,190
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	12,235			11,849
Amortization of intangibles	5,247			4,723
Loss on sale of property and equipment	270			170
Stock-based compensation expense	11,502			10,670
Amortization of premium on marketable securities	809			1,296
Deferred income taxes	152			(782		)
Increase in accounts receivable allowances	128			75
Excess tax benefit from employee stock plans	—			(437		)
Tax benefit (deficiency) associated with employee stock plans	(189		)	815
Change in operating assets and liabilities:
Accounts receivable	888			1,933
Inventories	9,995			(14,639		)
Prepaid expenses and other assets	4,278			9,955
Accounts payable	(2,035		)	2,509
Taxes payable and accrued liabilities	(3,579		)	(3,257		)
Deferred income on sales to distributors	1,241			3,017
Net cash provided by operating activities	67,388			73,087
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchases of property and equipment	(7,619		)	(17,394		)
Payment for purchase of building (Note 10)	(10,389		)	—
Payment for acquisition, net of cash acquired (Note 10)	(15,549		)	—
Other assets	—			(1,261		)
Purchases of marketable securities	(14,933		)	(45,269		)
Proceeds from sales and maturities of marketable securities	37,459			—
Net cash used in investing activities	(11,031		)	(63,924		)
CASH FLOWS FROM FINANCING ACTIVITIES:
Issuance of common stock under employee stock plans	6,902			13,104
Repurchase of common stock	(53,731		)	(45,258		)
Payments of dividends to stockholders	(10,501		)	(9,654		)
Excess tax benefit from employee stock plans	—			437
Net cash used in financing activities	(57,330		)	(41,371		)
NET DECREASE IN CASH AND CASH EQUIVALENTS	(973		)	(32,208		)
CASH AND CASH EQUIVALENTS AT BEGINNING OF PERIOD	60,708			92,928
CASH AND CASH EQUIVALENTS AT END OF PERIOD	$	59,735		$	60,720
SUPPLEMENTAL DISCLOSURE OF NON-CASH INVESTING AND FINANCING ACTIVITIES:
Unpaid property and equipment	$	3,216		$	4,359
Loan applied to CamSemi purchase price (Note 10)	$	6,600		$	—
SUPPLEMENTAL DISCLOSURE OF CASH FLOW INFORMATION:
Cash paid (refund) for income taxes, net	$	1,007		$	(3,707	)

The accompanying notes are an integral part of these unaudited condensed consolidated financial statements.

7

POWER INTEGRATIONS, INC.

NOTES TO UNAUDITED CONDENSED CONSOLIDATED FINANCIAL STATEMENTS

1. BASIS OF PRESENTATION:

The condensed consolidated financial statements include the accounts of Power Integrations, Inc., a Delaware corporation (the “Company”), and its wholly owned subsidiaries. Significant intercompany accounts and transactions have been eliminated in consolidation.

While the financial information furnished is unaudited, the condensed consolidated financial statements included in this report reflect all adjustments (consisting only of normal recurring adjustments) that the Company considers necessary for the fair presentation of the results of operations for the interim periods covered and the financial condition of the Company at the date of the interim balance sheet in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”). The results for interim periods are not necessarily indicative of the results for the entire year. The condensed consolidated financial statements should be read in conjunction with the Power Integrations, Inc. consolidated financial statements and the notes thereto for the year ended December 31, 2014, included in its Form 10-K filed on February 10, 2015, with the Securities and Exchange Commission.

2. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES:

No material changes have been made to the Company's significant accounting policies disclosed in Note 2, Summary of Significant Accounting Policies, in its Annual Report on Form 10-K, filed on February 10, 2015, for the year ended December 31, 2014. The accounting policy information below is to aid in the understanding of the financial information disclosed.

Cash and Cash Equivalents

The Company considers cash invested in highly liquid financial instruments with maturities of three months or less at the date of purchase to be cash equivalents.

Marketable Securities

The Company generally holds securities until maturity; however, they may be sold under certain circumstances including, but not limited to, when necessary for the funding of acquisitions, stock repurchases and other strategic investments. As a result the Company classifies its investment portfolio as available-for-sale. The Company classifies all investments with a maturity date greater than three months at the date of purchase as short-term marketable securities in its Condensed Consolidated Balance Sheets. As of September 30, 2015, and December 31, 2014, the Company's marketable securities consisted primarily of highly liquid corporate securities, commercial paper and other high-quality commercial securities.

Amortized cost and estimated fair market value of cash equivalents and marketable securities classified as available-for-sale at September 30, 2015, were as follows:

	Amortized Cost		Gross Unrealized					Estimated Fair Market Value
(In thousands)			Gains		Losses
Investments due in less than 3 months:
Commercial paper	$	18,019	$	—	$	—		$	18,019
Corporate securities	9,400		1		—			9,401
Total	27,419		1		—			27,420
Investments due in 4-12 months:
Corporate securities	64,306		72		(11		)	64,367
Total	64,306		72		(11		)	64,367
Investments due between 12 months and 5-years:
Corporate securities	5,004		5		—			5,009
Total	5,004		5		—			5,009
Total marketable securities	$	96,729	$	78	$	(11	)	$	96,796

8

POWER INTEGRATIONS, INC.

NOTES TO UNAUDITED CONDENSED CONSOLIDATED FINANCIAL STATEMENTS (Continued)

Amortized cost and estimated fair market value of marketable securities classified as available-for-sale at December 31, 2014, were as follows:    

	Amortized Cost		Gross Unrealized					Estimated Fair Market Value
(In thousands)			Gains		Losses
Investments due in 4-12 months:
Corporate securities	$	30,233	$	36	$	—		$	30,269
Total	30,233		36		—			30,269
Investments due between 12 months and 5-years:
Corporate securities	84,259		92		(45		)	84,306
Total	84,259		92		(45		)	84,306
Total marketable securities	$	114,492	$	128	$	(45	)	$	114,575

As of September 30, 2015, and December 31, 2014, the Company evaluated the nature of the investments with a loss position, which were primarily high-quality corporate securities, and determined the unrealized losses were not other-than-temporary.

Revenue Recognition

Product revenues consist of sales to original equipment manufacturers (“OEMs”), merchant power supply manufacturers and distributors. Approximately 76% of the Company's net product sales were made to distributors in the ninemonths ended September 30, 2015, and 75%in the twelve months ended December 31, 2014. The Company applies the provisions of Accounting Standard Codification (“ASC”) 605-10 (“ASC 605-10”) and all related appropriate guidance. Revenue is recognized when all of the following criteria have been met: (1) persuasive evidence of an arrangement exists, (2) delivery has occurred, (3) the price is fixed or determinable, and (4) collectability is reasonably assured. Customer purchase orders are generally used to determine the existence of an arrangement. Delivery is considered to have occurred when title and risk of loss have transferred to the Company's customer. The Company evaluates whether the price is fixed or determinable based on the payment terms associated with the transaction and whether the sales price is subject to refund or adjustment. With respect to collectability, the Company performs credit checks for new customers and performs ongoing evaluations of its existing customers' financial condition and requires letters of credit whenever deemed necessary.

Sales to international OEM customers and merchant power supply manufacturers that are shipped from the Company's facility in California are pursuant to “delivered at frontier” (“DAF”) shipping terms. As such, title to the product passes to the customer when the shipment reaches the destination country and revenue is recognized upon the arrival of the product in that country. Sales to international OEMs and merchant power supply manufacturers for shipments from the Company's facility outside of the United States are pursuant to “EX Works” ("EXW") shipping terms, meaning that title to the product transfers to the customer upon shipment from the Company's foreign warehouse. Shipments to OEMs and merchant power supply manufacturers in the Americas are pursuant to “free on board” (“FOB”) point of origin shipping terms, meaning that title is passed to the customer upon shipment. Revenue is recognized upon title transfer for sales to OEMs and merchant power supply manufacturers, assuming all other criteria for revenue recognition are met.

Sales to most of the Company's distributors are made under terms allowing certain price adjustments and rights of return on the Company's products held by its distributors. As a result of these rights, the Company defers the recognition of revenue and the costs of revenues derived from sales to distributors until the Company's distributors report that they have sold the Company's products to their customers. The Company's recognition of such distributor revenue is based on point of sale reports received from the distributors, at which time the price is no longer subject to adjustment and is fixed, and the products are no longer subject to return to the Company except pursuant to warranty terms. The gross profit that is deferred as a result of this policy is reflected as “deferred income on sales to distributors” in the accompanying condensed consolidated balance sheets. The total deferred revenue as of September 30, 2015, and December 31, 2014, was approximately $28.4 million and $25.0 million, respectively. The total deferred cost as of September 30, 2015, and December 31, 2014, was approximately $11.9 million and $9.8 million, respectively.

9

POWER INTEGRATIONS, INC.

NOTES TO UNAUDITED CONDENSED CONSOLIDATED FINANCIAL STATEMENTS (Continued)

Frequently, distributors need to sell at a price lower than the standard distribution price in order to win business. At or soon after the distributor invoices its customer, the distributor submits a “ship and debit” price adjustment claim to the Company to adjust the distributor's cost from the standard price to the pre-approved lower price. After verification by the Company, a credit memo is issued to the distributor for the ship and debit claim. The Company maintains a reserve for unprocessed claims and future ship and debit price adjustments. The reserve appears as a reduction to accounts receivable in the Company's accompanying consolidated balance sheets. To the extent future ship and debit claims significantly exceed amounts estimated, there could be a material impact on the deferred revenue and deferred margin ultimately recognized. To evaluate the adequacy of its reserves, the Company analyzes historical ship and debit payments and levels of inventory in the distributor channels.

Sales to certain of the Company's distributors are made under terms that do not include rights of return or price concessions after the product is shipped to the distributor. Accordingly, product revenue is recognized upon shipment and title transfer assuming all other revenue recognition criteria are met.

Common Stock Repurchases and Cash Dividend

In October 2012, the Company's board of directors authorized the use of $50.0 million for the repurchase of the Company's common stock. In the year ended December 31, 2014 and in July 2015, the Company's board of directors authorized the use of an additional $75.0 million and $30.0 million, respectively, for repurchase of the Company's common stock, with repurchases to be executed according to pre-defined price/volume guidelines. In the year ended December 31, 2014, the Company purchased 1.6 million shares for $80.8 million, and in the nine months ended September 30, 2015, the Company purchased approximately 1.3 million shares for $53.7 million. As of September 30, 2015, the Company had used up the amount authorized for repurchase.

In October 2015, the Company's board of directors authorized the use of an additional $30.0 million for the repurchase of the Company's common stock. Authorization of future repurchase programs is at the discretion of the board of directors and will depend on the Company's financial condition, results of operations, capital requirements, business conditions and other factors.

In October 2013, the Company's board of directors declared four quarterly cash dividends in the amount of $0.10 per share to be paid to stockholders of record at the end of each quarter in 2014. Dividend payouts totaling approximately $3.0 million each were paid on March 31, 2014 and June 30, 2014. In April 2014, the Company's board of directors increased the quarterly dividends for the third and fourth quarters of 2014 to $0.12 per share. Dividend payouts totaling approximately $3.6 million and $3.5 million were paid on September 30, 2014 and December 31, 2014, respectively.

In January 2015, the Company's board of directors extended the $0.12 quarterly dividend through each quarter in 2015. Dividend payouts totaling $3.5 million each were paid on March 31, June 30, and September 30, 2015. The declaration of any future cash dividend is at the discretion of the board of directors and will depend on the Company's financial condition, results of operations, capital requirements, business conditions and other factors, as well as a determination that cash dividends are in the best interests of the Company's stockholders.

Use of Estimates

The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosures of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. On an ongoing basis, the Company evaluates its estimates, including those related to revenue recognition, income tax, stock-based compensation and inventories. These estimates are based on historical facts and various other assumptions that the Company believes to be reasonable at the time the estimates are made.

Components of the Company's Condensed Consolidated Balance Sheets    

10

POWER INTEGRATIONS, INC.

NOTES TO UNAUDITED CONDENSED CONSOLIDATED FINANCIAL STATEMENTS (Continued)

Accounts Receivable:

(In thousands)	September 30, 2015			December 31, 2014
Accounts receivable trade	$	46,816		$	38,344
Accrued ship and debit and rebate claims	(35,436		)	(27,967		)
Allowance for doubtful accounts	(319		)	(191		)
Total	$	11,061		$	10,186

Prepaid Expenses and Other Current Assets:

(In thousands)	September 30, 2015		December 31, 2014
Prepaid legal fees	$	23	$	1,506
Loan to Cambridge Semiconductor (Note 10)	—		6,600
Prepaid income tax	1,386		3,208
Prepaid maintenance agreements	866		1,023
Interest receivable	371		664
VAT receivable	525		987
Supplier prepayment	366		800
Other	2,243		1,591
Total	$	5,780	$	16,379

Changes in accumulated other comprehensive income (loss) for the three months ended September 30, 2015 and 2014:

	Unrealized Gains and Losses on Marketable Securities					Defined Benefit Pension Items										Foreign Currency Items						Total
	Three Months Ended					Three Months Ended										Three Months Ended						Three Months Ended
	September 30,					September 30,										September 30,						September 30,
(In thousands)	2015		2014			2015					2014					2015			2014			2015			2014
Beginning balance	$	46	$	449		$	(1,212	)			$	(750	)			$	(1	)	$	111		$	(1,167	)	$	(190	)
Other comprehensive income (loss) before reclassifications	20		(246		)	—					—					40			(53		)	60			(299		)
Amounts reclassified from accumulated other comprehensive income	—		—			64			(1	)	15			(1	)	—			—			64			15
Net-current period other comprehensive income (loss)	20		(246		)	64					15					40			(53		)	124			(284		)
Ending balance	$	66	$	203		$	(1,148	)			$	(735	)			$	39		$	58		$	(1,043	)	$	(474	)

_______________

(1) This component of accumulated other comprehensive income is included in the computation of net periodic pension cost for the three months ended September 30, 2015 and 2014.

11

POWER INTEGRATIONS, INC.

NOTES TO UNAUDITED CONDENSED CONSOLIDATED FINANCIAL STATEMENTS (Continued)

Changes in accumulated other comprehensive income (loss) for the nine months ended September 30, 2015 and 2014:

	Unrealized Gains and Losses on Marketable Securities						Defined Benefit Pension Items										Foreign Currency Items					Total
	Nine Months Ended						Nine Months Ended										Nine Months Ended					Nine Months Ended
	September 30,						September 30,										September 30,					September 30,
(In thousands)	2015			2014			2015					2014					2015		2014			2015			2014
Beginning balance	$	83		$	210		$	(1,240	)			$	(780	)			$	21	$	100		$	(1,136	)	$	(470	)
Other comprehensive income (loss) before reclassifications	(17		)	(7		)	—					—					18		(42		)	1			(49		)
Amounts reclassified from accumulated other comprehensive income	—			—			92			(1	)	45			(1	)	—		—			92			45
Net-current period other comprehensive income (loss)	(17		)	(7		)	92					45					18		(42		)	93			(4		)
Ending balance	$	66		$	203		$	(1,148	)			$	(735	)			$	39	$	58		$	(1,043	)	$	(474	)

_______________

(1) This component of accumulated other comprehensive income is included in the computation of net periodic pension cost for the nine months ended September 30, 2015 and 2014.

3. STOCK PLANS AND SHARE-BASED COMPENSATION:

Stock Plans

As of September 30, 2015, the Company had two stock-based compensation plans (the “Plans”) which are described below.

2007 Equity Incentive Plan

The 2007 Equity Incentive Plan (the "2007 Plan") was adopted by the board of directors on September 10, 2007, and approved by the stockholders on November 7, 2007, as an amendment and restatement of the 1997 Stock Option Plan (the "1997 Plan"). The 2007 Plan provides for the grant of incentive stock options, non-statutory stock options, restricted stock awards, restricted stock unit ("RSU") awards, stock appreciation rights, performance-based ("PSU") awards , long-term performance based ("PRSU") awards and other stock awards to employees, directors and consultants. As of September 30, 2015, the maximum remaining number of shares that may be issued under the 2007 Plan was 6,377,504 shares, which includes options granted but not exercised and awards granted but unvested and shares remaining available for issuance under the 1997 Plan, including shares subject to outstanding options and stock awards under the 1997 Plan. Pursuant to the 2007 Plan, the exercise price for incentive stock options and non-statutory stock options is generally at least 100% of the fair market value of the underlying shares on the date of grant. Options generally vest over 48 months measured from the date of grant. Options generally expire no later than ten years after the date of grant, subject to earlier termination upon an optionee's cessation of employment or service.  

Beginning January 27, 2009, grants pursuant to the Directors Equity Compensation Program (which was adopted by the board of directors on January 27, 2009) to non-employee directors have been made primarily under the 2007 Plan. The Directors Equity Compensation Program provides for grants to outside directors as follows: effective annually, upon the first trading day of July, each outside director receives a grant of an equity award with an aggregate value of $100,000, which will become exercisable or vest immediately prior to the Company's next annual meeting of stockholders, subject to the director's continued service. At each outside director's election, such award may consist entirely of RSUs or entirely of stock options. The quantity of options would be calculated by dividing $100,000 by the Black-Scholes value on the date of grant. The quantity of RSUs issued would be calculated by dividing $100,000 by the grant-date fair value. Further, on the date of election of a new outside director, such new director would receive such grant as continuing outside directors receive on the first trading day of July; provided, however, that such grant is prorated for the portion of the year that such new outside director will serve until the next first trading day of

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July. The Directors Equity Compensation Program will remain in effect at the discretion of the board of directors or the compensation committee of the board.

On July 28, 2009, the 2007 Plan was amended generally to prohibit outstanding options or stock appreciation rights from being canceled in exchange for cash without stockholder approval.

1997 Employee Stock Purchase Plan

Under the 1997 Employee Stock Purchase Plan (the “Purchase Plan”), eligible employees may apply accumulated payroll deductions, which may not exceed 15% of an employee's compensation, to the purchase of shares of the Company's common stock at periodic intervals. The purchase price of stock under the Purchase Plan is equal to 85% of the lower of (i) the fair market value of the Company's common stock on the first day of each offering period, or (ii) the fair market value of the Company's common stock on the purchase date (as defined in the Purchase Plan). Each offering period consists of one purchase period of approximately six months' duration. An aggregate of 3,000,000 shares of common stock were reserved for issuance to employees under the Purchase Plan. As of September 30, 2015, 2,808,265 shares had been purchased and 191,735 shares were reserved for future issuance under the Purchase Plan.

Stock-Based Compensation

The Company applies the provisions of ASC 718-10. Under the provisions of ASC 718-10, the Company recognizes the fair value of stock-based compensation in financial statements over the requisite service period of the individual grants, which generally equals a four year vesting period. The Company uses estimates of volatility, expected term, risk-free interest rate, dividend yield and forfeitures in determining the fair value of these awards and the amount of compensation expense to recognize. The Company uses the straight-line method to amortize all stock awards granted over the requisite service period of the award, and uses historical data to estimate pre-vesting forfeitures, recognizing expense only for those awards that are expected to vest.

Determining Fair Value of Stock Options

The Company uses the Black-Scholes valuation model for valuing stock option grants using the following assumptions and estimates:

ExpectedVolatility. The Company calculates expected volatility based on the historical price volatility of the Company's stock.

Expected Term. The Company utilizes a model which uses historical exercise, cancellation and outstanding option data to calculate the expected term of stock option grants.

Risk-Free Interest Rate. The Company bases the risk-free interest rate used in the Black-Scholes valuation model on the implied yield available on a U.S. Treasury note with a term approximately equal to the expected term of the underlying grants.

Dividend Yield. The dividend yield was calculated by dividing the annual dividend by the average closing price of the Company's common stock on a quarterly basis.

The following table summarizes the stock-based compensation expense recognized in accordance with ASC 718-10 for the three and nine months ended September 30, 2015, and September 30, 2014:

	Three Months Ended				Nine Months Ended
	September 30,				September 30,
(In thousands)	2015		2014		2015		2014
Cost of revenues	$	219	$	131	$	725	$	648
Research and development	1,277		971		3,974		3,522
Sales and marketing	877		779		2,767		2,578
General and administrative	988		699		4,036		3,922
Total stock-based compensation expense	$	3,361	$	2,580	$	11,502	$	10,670

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Stock-based compensation expense in the three months ended September 30, 2015 was $3.4 million (comprising approximately $0.1 million related to stock options, a reduction to expense of $0.2 million related to PSUs and PRSUs, $3.2 million related to RSUs and $0.3 million related to the Purchase Plan). In the nine months ended September 30, 2015, stock compensation expense was $11.5 million (comprising approximately $0.5 million related to stock options, $0.6 million related to PSUs and PRSUs, $9.5 million related to RSUs and $0.9 million related to the Purchase Plan).

Stock-based compensation expense in the three months ended September 30, 2014, was $2.6 million (comprising approximately $0.2 million related to stock options, a reduction to expense of $0.8 million related to PSUs and PRSUs, $2.8 million related to RSUs and $0.4 million related to the Purchase Plan). In the nine months ended September 30, 2014, stock compensation expense was $10.7 million (comprising approximately $1.0 million related to stock options, $0.4 million related to PSUs and PRSUs, $8.4 million related to RSUs and $0.9 million related to the Purchase Plan).

The following table summarizes total compensation expense related to unvested awards not yet recognized, net of expected forfeitures, and the weighted-average period over which it is expected to be recognized as of September 30, 2015:

	September 30, 2015
	Unrecognized Compensation Expense for Unvested Awards (in thousands)		Weighted Average Remaining Recognition Period (in years)
Options	$	296	0.57
Performance-based awards	189		0.25
Long-term performance-based awards	606		1.81
Restricted stock unit awards	24,049		2.46
Purchase plan	434		0.34
Total unrecognized compensation expense	$	25,574

The fair value of employees’ stock purchase rights under the Purchase Plan was estimated using the Black-Scholes model with the following weighted-average assumptions:        

	Three Months Ended		Nine Months Ended
	September 30,		September 30,
	2015	2014	2015	2014
Risk-free interest rate	0.17%	0.05%	0.13%	0.05	%	-	0.07%
Expected volatility rate	26%	48%	29%	30	%	-	48%
Expected dividend yield	1.20%	0.85%	1.08%	0.66	%	-	0.85%
Expected term of purchase right (in years)	0.5	0.5	0.5	0.5
Weighted-average estimated fair value of purchase rights	$8.41	$15.25	$10.18	$14.40

The Company did not grant stock options in the three and nine months ended September 30, 2015, or September 30, 2014, and therefore no fair-value assumptions are reported.    

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A summary of stock option activity under the Plans, excluding PSUs, PRSUs and RSUs, as of September 30, 2015, and changes during the nine months then ended, is presented below:

	Shares (in thousands)		Weighted- Average Exercise Price	Weighted-Average Remaining Contractual Term (in years)	Aggregate Intrinsic Value (in thousands)
Outstanding at January 1, 2015	1,344		$27.27
Granted	—		—
Exercised	(96	)	$25.29
Forfeited or expired	(2	)	$37.97
Outstanding at September 30, 2015	1,246		$27.39	2.91	$	18,463
Exercisable at September 30, 2015	1,228		$27.17	2.86	$	18,463
Vested and expected to vest at September 30, 2015	1,246		$27.39	2.91	$	18,463

The Company did not grant stock options in the three and nine months ended September 30, 2015, and September 30, 2014. Beginning in 2010 the Company's equity grants to new hires and its annual incentive grants to non-executive employees have been primarily in the form of RSU's. The total intrinsic value of options exercised during the three and nine months ended September 30, 2015, was approximately $0.3 million and $2.4 million, respectively, and the total intrinsic value of options exercised during the three and nine months ended September 30, 2014, was approximately $1.8 million and $8.7 million, respectively.

PSU Awards

Under the PSU awards program, the Company grants awards in an amount equal to twice the target number of shares to be issued if the annual target performance metrics are met. The number of shares that are released at the end of the performance year can range from zero to 200% of the targeted number depending on the Company's performance. In 2015, the performance metrics of this program are annual targets consisting of net revenue, non-GAAP operating income and strategic goals. Each PSU granted from the 2007 Plan will reduce the number of shares available for issuance under the 2007 Plan by two shares.

During the nine months ended September 30, 2015, the Company granted approximately 88,000 annual PSUs to the Company's employees and executives. As the net revenue, non-GAAP operating earnings and strategic goals are considered performance conditions, expenses associated with these awards, net of estimated forfeitures, are recorded throughout the year depending on the number of shares expected to vest based on progress toward the performance targets. The fair value of PSUs is determined using the fair value of the Company's common stock on the grant date, reduced by the discounted present value of dividends expected to be declared before the awards vest. If the performance conditions are not achieved, no compensation cost is recognized and any previously recognized compensation is reversed.

In January 2015, it was determined that the Company had not reached the minimum level of the established 2014 performance targets (consisting of revenue and non-GAAP operating income). Accordingly, no shares subject to PSUs granted in connection with the 2014 performance based incentive plan were released to the Company's employees and executives in 2015.

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A summary of PSUs outstanding as of September 30, 2015, and activity during the nine months then ended, is presented below:

	Shares (in thousands)		Weighted- Average Grant Date Fair Value Per Share	Weighted-Average Remaining Contractual Term (in years)	Aggregate Intrinsic Value (in thousands)
Outstanding at January 1, 2015	—		—
Granted	88		$52.39
Vested	—		—
Change in units due to performance achievement for PSUs vested in the year	—		—
Forfeited or expired	(1	)	$50.79
Outstanding at September 30, 2015	87		$52.41	0.25	$	3,684
Outstanding and expected to vest at September 30, 2015	12			0.25	$	516

The weighted-average grant-date fair value per share of PSUs granted in the three and nine months ended September 30, 2015 was approximately $37.81 and $52.39, respectively, and $53.93 in the nine months ended September 30, 2014 (there were no PSUs granted in the three months ended September 30, 2014). There were no awards released in the three and nine months ended September 30, 2015. The grant-date fair value of awards released, which were fully vested, in the nine months ended September 30, 2014, was approximately $3.2 million. No awards were released in the three months ended September 30, 2014.

PRSU Awards

      In the first quarter of 2014 the Company began granting PRSU awards. The Company's PRSU program provides for the issuance of PRSUs which will vest based on the Company's performance measured against the PRSU Plan's established revenue targets. The PRSUs were granted in an amount equal to twice the target number of shares to be issued if the target performance metrics are met. The actual number of shares the recipient receives is determined at the end of a three-year performance period based on results achieved versus the Company's performance goals, and may range from zero to 200% of the target number. The performance goals for PRSUs granted in fiscal 2014 and 2015 were based on the Company's annual revenue growth. Each PRSU granted from the 2007 Plan will reduce the number of shares available for issuance under the 2007 Plan by two shares.

            Recipients of a PRSU generally must remain employed by the Company on a continuous basis through the end of the applicable three-year performance period in order to receive shares subject to that award. Expenses associated with these awards, net of estimated forfeitures, are recorded throughout the year depending on the number of shares expected to vest based on progress toward the performance target. The fair value of PRSU awards is determined using the fair value of the Company's common stock on the grant date, reduced by the discounted present value of dividends expected to be declared before the awards vest. If the performance conditions are not achieved, no compensation cost is recognized and any previously recognized compensation is reversed.

A summary of PRSUs outstanding as of September 30, 2015, and activity during the nine months then ended, is presented below:

	Shares (in thousands)		Weighted- Average Grant Date Fair Value Per Share	Weighted-Average Remaining Contractual Term (in years)	Aggregate Intrinsic Value (in thousands)
Outstanding at January 1, 2015	61		$55.51
Granted	72		$52.47
Vested	—		—
Forfeited or expired	(4	)	$57.76
Outstanding at September 30, 2015	129		$53.75	1.81	$	5,427
Outstanding and expected to vest at September 30, 2015	17			1.79	$	724

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The weighted-average grant-date fair value per share of PRSUs granted in the nine months ended September 30, 2015 and September 30, 2014, was approximately $52.47 and $56.15, respectively (there were no PRSUs granted in the three months ended September 30, 2015, or September 30, 2014).

RSU Awards

The Company grants RSUs to employees under the 2007 Plan. RSUs granted to employees typically vest ratably over a four year period, and are converted into shares of the Company's common stock upon vesting on a one-for-one basis subject to the employee's continued service with the Company over that period. The fair value of RSUs is determined using the fair value of the Company's common stock on the date of the grant, reduced by the discounted present value of dividends expected to be declared before the awards vest. Compensation expense is recognized on a straight-line basis over the requisite service period of each grant adjusted for estimated forfeitures. Each RSU award granted from the 2007 plan will reduce the number of shares available for issuance under the 2007 Plan by two shares.

A summary of RSUs outstanding as of September 30, 2015, and changes during the nine months then ended, are as follows:

	Shares (in thousands)		Weighted- Average Grant Date Fair Value Per Share	Weighted-Average Remaining Contractual Term (in years)	Aggregate Intrinsic Value (in thousands)
Outstanding at January 1, 2015	692		$43.86
Granted	302		$49.90
Vested	(257	)	$42.49
Forfeited or expired	(48	)	$45.55
Outstanding at September 30, 2015	689		$46.90	1.46	$	29,073
Outstanding and expected to vest at September 30, 2015	636			1.40	$	26,804

The weighted-average grant-date fair value per share of RSUs awarded in the three and nine months ended September 30, 2015, was approximately $42.65 and $49.90, respectively, and $58.03 and $51.30, respectively, in the corresponding periods of the previous year. The grant-date fair value of RSUs vested in the three and nine months ended September 30, 2015, was approximately $0.4 million and $10.9 million, respectively, and $0.5 million and $10.0 million, respectively, in the corresponding periods of the previous year.

4. FAIR VALUE MEASUREMENTS:

ASC 820-10, Fair Value Measurements, clarifies that fair value is an exit price, representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. As such, fair value is a market-based measurement that should be determined based on assumptions that market participants would use in pricing an asset or liability. As a basis for considering such assumptions, ASC 820-10 establishes a three-tier value hierarchy, which prioritizes the inputs used in measuring fair value as follows: (Level 1) observable inputs such as quoted prices for identical assets in active markets; (Level 2) inputs other than the quoted prices in active markets that are observable either directly or indirectly; and (Level 3) unobservable inputs in which there is little or no market data, which requires the Company to develop its own assumptions. This hierarchy requires the Company to use observable market data, when available, and to minimize the use of unobservable inputs when determining fair value.

The Company's cash equivalents and short-term marketable securities are classified within Level 1 or Level 2 of the fair-value hierarchy because they are valued using quoted market prices, broker or dealer quotations, or alternative pricing sources with reasonable levels of price transparency. The type of instrument valued based on quoted market prices in active markets primarily includes money market securities. This type of instrument is generally classified within Level 1 of the fair-value hierarchy. The types of instruments valued based on other observable inputs (Level 2 of the fair-value hierarchy) generally include investment-grade corporate bonds, government, state, municipal and provincial obligations and commercial paper. Such types of investments are valued by using a multi-dimensional relational model, the inputs are primarily benchmark yields, reported trades, broker/dealer

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quotes, issuer spreads, two-sided markets, benchmark securities, bids, offers, and reference data including market research publications. The Company's investments classified as Level 1 and Level 2 are available-for-sale investments, and were recorded at fair market value.

The fair-value hierarchy of the Company's marketable securities at September 30, 2015, and December 31, 2014, was as follows:

	Fair Value Measurement at
	September 30, 2015
(In thousands)	Total Fair Value		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)
Commercial paper	$	18,019	$	—	$	18,019
Money market funds	11,742		11,742		—
Corporate securities	78,777		—		78,777
Total	$	108,538	$	11,742	$	96,796

	Fair Value Measurement at
	December 31, 2014
(In thousands)	Total Fair Value		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)
Money market funds	$	3,370	$	3,370	$	—
Corporate securities	114,575		—		114,575
Total	$	117,945	$	3,370	$	114,575

The Company did not transfer any investments between Level 1 and Level 2 of the fair-value hierarchy in the nine months ended September 30, 2015, and the twelve months ended December 31, 2014.

5. INVENTORIES:

Inventories (which consist of costs associated with the purchases of wafers from domestic and offshore foundries and of packaged components from offshore assembly manufacturers, as well as internal labor and overhead associated with the testing of both wafers and packaged components) are stated at the lower of cost (first-in, first-out) or market. Provisions, when required, are made to reduce excess and obsolete inventories to their estimated net realizable values.

Inventories consist of the following:

(In thousands)	September 30, 2015		December 31, 2014
Raw materials	$	18,661	$	21,127
Work-in-process	14,659		14,643
Finished goods	22,119		28,255
Total	$	55,439	$	64,025

6. GOODWILL AND INTANGIBLE ASSETS:

Goodwill increased during the nine months ended September 30, 2015, due to the Company's acquisition of Cambridge Semiconductor Limited ("CamSemi") (refer to Note 10, Acquisitions, for details on the Company's CamSemi acquisition). Changes in the carrying amount of goodwill during the nine months ended September 30, 2015, are as follows:

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(In thousands)	Goodwill
Balance at December 31, 2014	$	80,599
Goodwill acquired during the period	11,250
Ending balance at September 30, 2015	$	91,849

Intangible assets consist primarily of developed technology, acquired licenses, customer relationships, trade name, in-process research and development and patent rights, and are reported net of accumulated amortization. In January 2015, the Company acquired CamSemi, resulting in the addition of the following intangible assets: developed technology of $6.6 million, which will be amortized over a period of 3 - 7 years; and customer relationships of $2.4 million, which will be amortized over a period of 5 years. In August 2015, the Company purchased a building with existing third-party leases, resulting in the addition of in-place lease intangible assets of $0.7 million which will be amortized over a period of 2 years.

The Company amortizes the cost of all intangible assets over the shorter of the estimated useful life or the term of the developed technology, acquired licenses, customer relationships, trade name, patent rights and contractual lease period, which range from 2 to 12 years, with the exception of $1.3 million for the purchase of an internet domain name (the cost to acquire the domain name has been recorded as an intangible asset and will not be amortized as it has an indefinite useful life), and $4.7 million of in-process research and development. In-process research and development is assessed for impairment until the development is completed and products are available for sale, at which time the Company will begin to amortize the in-process research and development. The Company does not expect amortization of the capitalized in-process research and development to begin in 2015.

Amortization for acquired intangible assets was approximately $1.7 million and $5.2 million in the three and nine months ended September 30, 2015, respectively, and $1.3 million and $4.7 million, respectively, in the corresponding periods of the previous year. The Company does not believe there is any significant residual value associated with its finite-lived intangible assets:

	September 30, 2015							December 31, 2014
(In thousands)	Gross		Accumulated Amortization			Net		Gross		Accumulated Amortization			Net
Domain name	$	1,261	$	—		$	1,261	$	1,261	$	—		$	1,261
In-process research and development	4,690		—			4,690		4,690		—			4,690
Technology licenses	3,000		(2,850		)	150		3,000		(2,625		)	375
Patent rights	1,949		(1,949		)	—		1,949		(1,949		)	—
Developed technology	33,270		(10,708		)	22,562		26,670		(7,828		)	18,842
Customer relationships	20,030		(9,366		)	10,664		17,610		(7,254		)	10,356
Trade name	3,600		(3,600		)	—		3,600		(3,600		)	—
In-place leases	660		(30		)	630		—		—			—
Total intangible assets	$	68,460	$	(28,503	)	$	39,957	$	58,780	$	(23,256	)	$	35,524

The estimated future amortization expense related to finite-lived intangible assets at September 30, 2015, is as follows:

Fiscal Year	Estimated Amortization (in thousands)
2015 (remaining 3 months)	$	1,792
2016	6,663
2017	6,084
2018	5,152
2019	4,753
Thereafter	9,562
Total (1)	$	34,006

_______________

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(1) The total above excludes $4.7 million of in-process research and development that will be amortized, upon completion of development, over the estimated useful life of the technology.

7. SIGNIFICANT CUSTOMERS AND INTERNATIONAL SALES:

Segment Reporting

The Company is organized and operates as one reportable segment, the design, development, manufacture and marketing of integrated circuits and related components for use primarily in the high-voltage power-conversion market. The Company's chief operating decision maker, the Chief Executive Officer, reviews financial information presented on a consolidated basis for purposes of making operating decisions and assessing financial performance.

Customer Concentration

The Company's top ten customers accounted for approximately 64% and 61% of net revenues for the three and nine months ended September 30, 2015, respectively, and approximately 59% of net revenues in each of the corresponding periods of the previous year. A significant portion of these revenues are attributable to sales of the Company’s products to distributors of electronic components. These distributors sell the Company’s products to a broad, diverse range of end users, including OEMs and merchant power supply manufacturers.

One customer, a distributor of the Company's products, accounted for more than 10% of the Company's net revenues in the three and nine months ended September 30, 2015, and in the corresponding periods of 2014. A second customer, also a distributor, accounted for more than 10% of net revenues in the three month period ended September 30, 2015. The following table discloses these customers' percentage of revenues for the respective periods:    

	Three Months Ended				Nine Months Ended
	September 30,				September 30,
Customer	2015		2014		2015		2014
Avnet	20	%	19	%	21	%	20	%
Powertech Distribution Ltd.	11	%	*		*		*

_______________                        

* Total customer percentage of revenues was less than 10%.

No other customers accounted for 10% or more of the Company's net revenues in the periods presented.

Concentration of Credit Risk

Financial instruments that potentially subject the Company to concentrations of credit risk consist principally of cash investments and trade receivables. The Company has cash investment policies that limit cash investments to low-risk investments. With respect to trade receivables, the Company performs ongoing evaluations of its customers' financial conditions and requires letters of credit whenever deemed necessary. Additionally, the Company establishes an allowance for doubtful accounts based upon factors surrounding the credit risk of specific customers, historical trends related to past write-offs and other relevant information. Account balances are charged off against the allowance after all means of collection have been exhausted and the potential for recovery is considered remote. The Company does not have any off-balance-sheet credit exposure related to its customers. As of September 30, 2015, and December 31, 2014, 65% and 66%, respectively, of accounts receivable were concentrated with the Company's top 10 customers.

The following customers represented 10% or more of accounts receivable:

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Customer	September 30, 2015		December 31, 2014
Avnet	23	%	22	%
ATM Electronic Corporation	12	%	*
Burnon International LTD.	*		11	%

_______________                        

* Total customer accounts receivable was less than 10%.

The above-mentioned customers are distributors of the Company’s products. No other customers accounted for 10% or more of the Company’s accounts receivable on these dates.

International Sales

The Company markets its products globally through its sales personnel and a worldwide network of independent sales representatives and distributors. As a percentage of total net revenues, international sales, which consist of sales to distributors and direct customers outside of the United States of America, comprise the following:     

	Three Months  Ended				Nine Months Ended
	September 30,				September 30,
	2015		2014		2015		2014
Hong Kong/China	49	%	47	%	49	%	46	%
Taiwan	15	%	16	%	14	%	16	%
Korea	10	%	11	%	10	%	11	%
Western Europe (excluding Germany)	11	%	11	%	11	%	11	%
Japan	4	%	5	%	5	%	5	%
Germany	3	%	2	%	3	%	2	%
Other	3	%	4	%	3	%	4	%
Total foreign revenue	95	%	96	%	95	%	95	%

The remainder of the Company’s sales is to customers within the United States of America.

Product Sales

Net revenues consist primarily of sales of the Company's high-voltage integrated-circuit products, insulated-gate bipolar transistor ("IGBT") drivers and high-voltage silicon diodes. When evaluating the Company's net revenues, the Company categorizes its sales into the following four end-market groupings: communications, computer, consumer and industrial. The table below provides the percentage of net sales activity by end market for the three and nine months ended September 30, 2015 and 2014:

	Three Months Ended				Nine Months Ended
	September 30,				September 30,
End Market	2015		2014		2015		2014
Communications	26	%	18	%	23	%	17	%
Computer	7	%	11	%	7	%	11	%
Consumer	36	%	36	%	37	%	37	%
Industrial	31	%	35	%	33	%	35	%

8. EARNINGS PER SHARE:

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Basic earnings per share are calculated by dividing net income by the weighted-average shares of common stock outstanding during the period. Diluted earnings per share are calculated by dividing net income by the weighted-average shares of common stock and dilutive common equivalent shares outstanding during the period. Dilutive common equivalent shares included in this calculation consist of dilutive shares issuable upon the assumed exercise of outstanding common stock options, the assumed vesting of outstanding restricted stock units and both short- and long-term performance-based awards, and the assumed issuance of awards under the stock purchase plan, as computed using the treasury stock method.

A summary of the earnings per share calculation is as follows:        

	Three Months Ended				Nine Months Ended
	September 30,				September 30,
(In thousands, except per share amounts)	2015		2014		2015		2014
Basic earnings per share:
Net income	$	11,513	$	16,111	$	26,446	$	45,190
Weighted-average common shares	28,855		30,013		29,175		30,186
Basic earnings per share	$	0.40	$	0.54	$	0.91	$	1.50
Diluted earnings per share: (1)
Net income	$	11,513	$	16,111	$	26,446	$	45,190
Weighted-average common shares	28,855		30,013		29,175		30,186
Effect of dilutive awards:
Employee stock plans	443		744		681		867
Diluted weighted-average common shares	29,298		30,757		29,856		31,053
Diluted earnings per share	$	0.39	$	0.52	$	0.89	$	1.46

_______________ 

(1) The Company includes the shares underlying performance-based awards in the calculation of diluted earnings per share if the performance conditions have been satisfied as of the end of the reporting period and excludes such shares when the necessary conditions have not been met. The Company has excluded the shares underlying the 2015 and 2014 awards in the 2015 and 2014 calculations, respectively, as those shares were not contingently issuable as of the end of the period. 

In the three and nine months ended September 30, 2015, 69,000 and 8,000 outstanding stock awards were determined to be anti-dilutive, respectively, and therefore were excluded in the computation of diluted earnings per share. In the three and nine months ended September 30, 2014, no outstanding stock awards were determined to be anti-dilutive, and therefore no stock awards were excluded in the computation of diluted earnings per share.

9. PROVISION FOR INCOME TAXES:

Income-tax expense includes a provision for federal, state and foreign taxes based on the annual estimated effective tax rate applicable to the Company and its subsidiaries, adjusted for certain discrete items which are fully recognized in the period they occur.

The Company's effective tax rates for the three and nine months ended September 30, 2015, were 5.7% and 6.1%, respectively. The difference between the expected statutory rate of 35% and the Company's effective tax rates for the three and nine months ended September 30, 2015, was due primarily to the beneficial impact of the geographic distribution of the Company's world-wide earnings. The Company's effective tax rates for the three and nine months ended September 30, 2014, were 6.6% and (0.9)%, respectively. The difference between the expected statutory rate of 35% and the effective tax rates for the three and nine months ended September 30, 2014, was due primarily to the beneficial impact of the geographic distribution of the Company's world-wide earnings and additionally, for the nine months ended September 30, 2014, the Company's 2014 settlement with the IRS. The provision for income tax for the nine months ended September 30, 2014, includes, in the second quarter of 2014, a one-time benefit of $3.3 million comprising $2.8 million in federal income taxes and interest, and state income taxes of approximately $0.5 million. The one-time benefit includes the reversal of $4.1 million of related unrecognized tax benefits that had been recorded

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as non-current liabilities in the Company's consolidated balance sheets. The Company has now concluded all U.S. federal income-tax matters for the years through 2009.

The Company accounts for income taxes under the provisions of ASC 740. Under the provisions of ASC 740, deferred tax assets and liabilities are recognized based on the differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases, utilizing the tax rates that are expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled.

In assessing the realizability of deferred tax assets, management considers whether it is more likely than not that some portion or all of the deferred tax assets will not be realized. The ultimate realization of deferred tax assets is dependent upon the generation of future taxable income during the periods in which those temporary differences become deductible. Management considers the scheduled reversal of deferred tax liabilities and projected future taxable income. In the event that the Company determines, based on available evidence and management judgment, that all or part of the net deferred tax assets will not be realized in the future, the Company would record a valuation allowance in the period the determination is made. In addition, the calculation of tax liabilities involves significant judgment in estimating the impact of uncertainties in the application of complex tax laws. Resolution of these uncertainties in a manner inconsistent with the Company's expectations could have a material impact on its results of operations and financial position.

As of September 30, 2015, the Company maintains a valuation allowance on its California deferred tax assets, New Jersey deferred tax assets, capital losses for federal purposes and a valuation allowance with respect to its deferred tax assets relating to tax credits in Canada.

To ensure an additional source of U.S. cash, the Company plans to repatriate a portion of its current year offshore earnings to the U.S. for domestic operations and accordingly has provided for estimated federal and state income taxes on such portion of its current year offshore earnings. If circumstances change and it becomes apparent that some or all of the undistributed earnings of the Company's offshore subsidiary will be remitted in the foreseeable future but income taxes have not been recognized, the Company will accrue income taxes attributable to such undistributed earnings.

Determining the consolidated provision for (benefit from) income tax expense, income tax liabilities and deferred tax assets and liabilities involves judgment. The Company calculates and provides for income taxes in each of the tax jurisdictions in which it operates, which involves estimating current tax exposures as well as making judgments regarding the recoverability of deferred tax assets in each jurisdiction. The estimates used could differ from actual results, which may have a significant impact on operating results in future periods.

On July 27, 2015, in Altera Corp. v. Commissioner, the U.S. Tax Court issued an opinion related to the treatment of stock-based compensation expense in an intercompany cost-sharing arrangement. A final decision has yet to be issued by the Tax Court due to other outstanding issues related to the case. At this time, the U.S. Department of the Treasury has not withdrawn the requirement to include stock-based compensation expense from IRS cost-sharing regulations. The Company has reviewed this case and its impact and concluded that no adjustment to the consolidated financial statements is appropriate at this time. The Company will continue to monitor ongoing developments and potential impacts to the consolidated financial statements.

10. ACQUISITIONS:

Cambridge Semiconductor Limited

In December 2014, the Company entered into a loan agreement with Cambridge Semiconductor Limited ("CamSemi"), a UK company, in which $6.6 million was outstanding as of December 31, 2014. The estimated fair value of the loan approximated the carrying value of $6.6 million, as the loan was outstanding for less than a month and the interest rate approximated a market rate for such a loan. The loan was in anticipation of a definitive agreement the Company entered into to acquire CamSemi in January 2015.

On January 2, 2015, the Company acquired 100% of the shares outstanding of CamSemi for total consideration of approximately $23.3 million, of which $16.7 million was paid in cash and $6.6 million was applied against the outstanding loan owed to the Company. The acquisition-related costs for the purchase of CamSemi were $0.2 million in the nine months ended

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September 30, 2015, and $0.8 million in the three months ended December 31, 2014. The acquisition has been accounted for using the acquisition method of accounting in accordance with ASC 805 - Business Combinations. Goodwill is not expected to be deductible for tax purposes.

CamSemi was acquired to accelerate the Company's product-development efforts for the low-power market. The acquisition also broadens the Company's technology and product portfolio for low-power applications, particularly in the mobility and light-emitting diode ("LED") lighting markets. The purchase price allocated to goodwill in the acquisition (as noted in the purchase price allocation below) is related largely to synergies and economies of scale expected from combining the operations of CamSemi with those of the Company.

The following table summarizes the purchase price and preliminary estimated fair values of the assets acquired and the liabilities assumed as of January 2, 2015. The allocation of the purchase price is preliminary as certain pre-acquisition liabilities and corporate taxes are still being finalized and may be adjusted should further information regarding events or circumstances existing as of the acquisition date become available.

(In thousands)		Total Amount
Assets Acquired
	Cash	$	1,134
	Accounts receivable	1,891
	Inventories	1,409
	Prepaid expenses and other current assets	408
	Tax receivable	1,093
	Intangible assets:
	Developed technology	6,600
	Customer relationships	2,420
	Goodwill	11,250
	Total assets acquired	26,205
Liabilities Assumed
	Current liabilities	1,832
	Taxes payable	1,090
	Total liabilities assumed	2,922
	Total purchase price	$	23,283

The following table represents details of the purchased intangible assets:

	Fair Value Amount (in thousands)		Estimated Useful Life (in years)
Developed technology	$	6,600	3	-	7
Customer relationships	2,420		5
Total acquired CamSemi intangibles	$	9,020

The fair value of the identifiable intangible assets, developed technology and customer relationships, were determined based on the following approach.

Developed Technology.The income approach was used to value the acquired developed technology. Revenue attributable to the Company's technology was estimated based on expected evolution of the technology over time. Expenses were assumed to reflect the costs necessary to support the developed technology.  The present value was capitalized as developed technology as of the acquisition date and is being amortized using a straight-line method to cost of revenues over the estimated life of 3 - 7 years.

Customer Relationships. An intangible customer relationship asset was recognized to the extent that the Company was expected to benefit from future revenues reasonably anticipated given the historical customer relationships and operating practices of CamSemi. In order to determine the fair value of the customer relationships, the Company's analysis assumed that the Company

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would immediately benefit from the economics generated by CamSemi's existing customer relationships.  This amount was reduced by the potential impact given no past customer relationships and the assumption that the Company could reacquire the customer relationships and ramp up to a similar level of revenue within two years.  The fair value of customer relationships was capitalized as of the acquisition date and is being amortized on a straight line basis to sales and marketing expenses over the estimated life of 5 years.

Pro forma results of operations for this acquisition have not been presented because it is not material to the Company’s condensed consolidated financial statements.

Corporate Headquarters Building

In August, 2015, the Company purchased a building adjacent to the corporate headquarters in San Jose, California to support the overall growth of the business. The purchase has been accounted for using the acquisition method of accounting in accordance with ASC 805 - Business Combinations, as the building had existing rental income resulting from in-place lease agreements with third-party tenants. The aggregate purchase price of $10.4 million, funded with cash on hand, was allocated as follows: $3.5 million for land, $6.3 million for building and improvements, $0.7 million for in-place leases and $(0.1) million for liabilities assumed. The building and improvements are being depreciated on a straight-line basis over an estimated useful life of up to 30 years. Additionally, as a result of the purchase, the Company acquired existing third-party leases that were valued as in-place lease intangible assets and are being amortized over the weighted average estimated life of 2 years. The valuation of the acquired in-place leases were estimated by the Company based on the amount of avoided cash outflows necessary to originate such leases. Acquisition-related costs in connection with the building purchase were included in other income, net in the consolidated statements of income and were not material for the periods presented. The allocation of the purchase price is preliminary and may be adjusted should further information regarding events or circumstances existing as of the acquisition date become available.

Rental income from the third-party leases, and the proportionate share of building expenses for those leases, are included in other income, net in the consolidated statements of income from the date of acquisition. These amounts were not material for the periods presented.

11. COMMITMENTS:

Supplier Agreements

Under the terms of the Company's wafer-supply agreements with Seiko Epson Corporation ("Epson"), and ROHM Lapis Semiconductor Co., Ltd. ("Lapis") the wafers purchased from these suppliers are priced in U.S. dollars; however, these agreements also allow for mutual sharing of the impact of the exchange rate fluctuation between Japanese yen and the U.S. dollar on future purchases. Each year, the Company's management and these two suppliers review and negotiate future pricing; the negotiated pricing is denominated in U.S. dollars but is subject to contractual exchange rate provisions. The fluctuation in the exchange rate is shared equally between the Company and each of these suppliers on future purchases.

12. LEGAL PROCEEDINGS AND CONTINGENCIES:

From time to time in the ordinary course of business, the Company becomes involved in lawsuits, or customers and distributors may make claims against the Company. In accordance with ASC 450-10, the Company makes a provision for a liability when it is both probable that a liability has been incurred and the amount of the loss can be reasonably estimated.

On October 20, 2004, the Company filed a complaint against Fairchild Semiconductor International, Inc. and Fairchild Semiconductor Corporation (referred to collectively as "Fairchild") in the United States District Court for the District of Delaware. In its complaint, the Company alleged that Fairchild has and is infringing four of Power Integrations' patents pertaining to pulse width modulation (“PWM”) integrated circuit devices. Fairchild denied infringement and asked for a declaration from the court that it does not infringe any Power Integrations patent and that the patents are invalid. The Court issued a claim construction order on March 31, 2006 which was favorable to the Company. The Court set a first trial on the issues of infringement, willfulness and damages for October 2, 2006. At the close of the first trial, on October 10, 2006, the jury returned a verdict in favor of the Company

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finding all asserted claims of all four patents-in-suit to be willfully infringed by Fairchild and awarding $34.0 million in damages. Fairchild raised defenses contending that the asserted patents are invalid or unenforceable, and the Court held a second trial on these issues beginning on September 17, 2007. On September 21, 2007, the jury returned a verdict in the Company's favor, affirming the validity of the asserted claims of all four patents-in-suit. Fairchild submitted further materials on the issue of enforceability along with various other post-trial motions, and the Company filed post-trial motions seeking a permanent injunction and increased damages and attorneys' fees, among other things. On September 24, 2008, the Court denied Fairchild's motion regarding enforceability and ruled that all four patents are enforceable. On December 12, 2008, the Court ruled on the remaining post-trial motions, including granting a permanent injunction, reducing the damages award to $6.1 million, granting Fairchild a new trial on the issue of willful infringement in view of an intervening change in the law, and denying the Company's motion for increased damages and attorneys' fees with leave to renew the motion after the resolution of the issue of willful infringement. On December 22, 2008, at Fairchild's request, the Court temporarily stayed the permanent injunction for 90 days. On January 12, 2009, Fairchild filed a notice of appeal challenging the Court's refusal to enter a more permanent stay of the injunction, and Fairchild filed additional motions requesting that both the Federal Circuit and the District Court extend the stay of injunction. The District Court temporarily extended the stay pending the Federal Circuit ruling on Fairchild's pending motion, but the Federal Circuit dismissed Fairchild's appeal and denied its motion on May 5, 2009, and the District Court issued an order on May 13, 2009 confirming the reinstatement of the permanent injunction as originally entered in December 2008. On June 22, 2009, the Court held a brief bench re-trial on the issue of willful infringement. On July 22, 2010, the Court found that Fairchild willfully infringed all four of the asserted patents, and the Court also invited briefing on enhanced damages and attorneys' fees. Fairchild also filed a motion requesting that the Court amend its findings regarding willfulness. On January 18, 2011, the Court denied Fairchild's request to amend the findings regarding Fairchild's willful infringement and doubled the damages award against Fairchild but declined to award attorneys' fees. On February 3, 2011, the Court entered final judgment in favor of the Company for a total damages award of $12.9 million. Fairchild filed a notice of appeal challenging the final judgment and a number of the underlying rulings, and the Company filed a cross-appeal seeking to increase the damages award. The appeal was argued on January 11, 2012, and the Federal Circuit issued a mixed ruling on March 26, 2013, affirming Fairchild's infringement of certain claims that support the basis for the permanent injunction while reversing, vacating, and remanding the findings with respect to other claims, including the Company's claim for damages. The Company filed a petition seeking Supreme Court review of the Federal Circuit’s ruling on damages issues, and the Supreme Court called for a response from Fairchild but ultimately declined to review the case. On remand, the Company intends to pursue its claim for financial compensation based on Fairchild's infringement.

On May 9, 2005, the Company filed a Complaint with the U.S. International Trade Commission (“ITC”) under section 337 of the Tariff Act of 1930, as amended, 19 U.S.C. section 1337 against System General (“SG”). The Company filed a supplement to the complaint on May 24, 2005. The Company alleged infringement of its patents pertaining to PWM integrated circuit devices produced by SG, which are used in power conversion applications such as power supplies for computer monitors. The Commission instituted an investigation on June 8, 2005 in response to the Company's complaint. SG filed a response to the ITC complaint asserting that the patents-in-suit were invalid and not infringed. The Company subsequently and voluntarily narrowed the number of patents and claims in suit, which proceeded to a hearing. The hearing on the investigation was held before the Administrative Law Judge (“ALJ”) from January 18 to January 24, 2006. Post-hearing briefs were submitted and briefing concluded February 24, 2006. The ALJ's initial determination was issued on May 15, 2006. The ALJ found all remaining asserted claims valid and infringed, and recommended the exclusion of the infringing products as well as certain downstream products that contain the infringing products. After further briefing, on June 30, 2006, the Commission decided not to review the initial determination on liability, but did invite briefs on remedy, bonding and the public interest. On August 11, 2006, the Commission issued an order excluding from entry into the United States the infringing SG PWM chips, and any liquid-crystal-display ("LCD") computer monitors, AC printer adapters and sample/demonstration circuit boards containing an infringing SG chip. The U.S. Customs Service is authorized to enforce the exclusion order. On October 11, 2006, the presidential review period expired without any action from the President, and the ITC exclusion order is now in full effect. SG appealed the ITC decision, and on November 19, 2007, the Federal Circuit affirmed the ITC's findings in all respects. On October 27, 2008, SG filed a petition to modify the exclusion order in view of a recent Federal Circuit opinion in an unrelated case, and the Company responded to oppose any modification, but the Commission modified the exclusion order on February 27, 2009. Nevertheless, the exclusion order still prohibits SG and related entities from importing the infringing SG chips and any LCD computer monitors, AC printer adapters, and sample/demonstration circuit boards containing an infringing SG chip.

On May 23, 2008, the Company filed a complaint against Fairchild Semiconductor International, Inc., Fairchild Semiconductor Corporation, and Fairchild's wholly owned subsidiary System General Corporation (referred to collectively as “Fairchild”), in the United States District Court for the District of Delaware. In its complaint, the Company alleged that Fairchild

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has infringed and is infringing three patents pertaining to power supply controller integrated circuit devices. Fairchild answered the Company's complaint on November 7, 2008, denying infringement and asking for a declaration from the Court that it does not infringe any Power Integrations patent and that the patents are invalid and unenforceable. Fairchild's answer also included counterclaims accusing the Company of infringing three patents pertaining to primary side power conversion integrated circuit devices. Fairchild had earlier brought these same claims in a separate suit against the Company, also in Delaware, which Fairchild dismissed in favor of adding its claims to the Company's already pending suit against Fairchild. The Company has answered Fairchild's counterclaims, denying infringement and asking for a declaration from the Court that it does not infringe any Fairchild patent and that the Fairchild patents are invalid. Fairchild also filed a motion to stay the case, but the Court denied that motion on December 19, 2008. On March 5, 2009, Fairchild filed a motion for summary judgment to preclude any recovery for post-verdict sales of parts found to infringe in the parties' other ongoing litigation, described above, and the Company filed its opposition and a cross-motion to preclude Fairchild from re-litigating the issues of infringement and damages for those same products. On June 26, 2009, the Court held a hearing on the parties' motions, and on July 9, 2009 the Court issued an order denying the parties' motions but staying proceedings with respect to the products that were found to infringe and which are subject to the injunction in the other Delaware case between the parties pending the entry of final judgment in that case; those products are expected to be addressed in the context of the parties’ remand proceedings following the appeal in their earlier litigation in Delaware, and the remainder of the case is proceeding. On December 18, 2009, the Court issued an order construing certain terms in the asserted claims of the Company's and Fairchild's patents in suit. Following the Court's ruling on claim construction, Fairchild withdrew its claim related to one of its patents and significantly reduced the number of claims asserted for the remaining two patents. The parties thereafter filed and argued a number of motions for summary judgment, and the Court denied the majority of the parties' motions but granted the Company's motion to preclude Fairchild from re-arguing validity positions that were rejected in the prior case between the parties. Because the assigned Judge retired at the end of July 2010, the case was re-assigned to a different Judge, and the Court vacated the trial schedule and had the parties provide their input on the appropriate course of action. The Court thereafter set a trial schedule with the jury trial on infringement and validity to begin in July 2011. On April 18, 2011, the Court rescheduled the trial to begin in January 2012, and on June 2, 2011, the Court moved the trial date to April 2012 to permit the parties to address another patent the Company accused Fairchild of infringing. Following a trial in April 2012, the jury returned a verdict finding that Fairchild infringes two of the Company's patents, that Fairchild has induced others to infringe the Company's patents, and also upheld the validity of the infringed patents. Of the two remaining counterclaim patents Fairchild asserted in the case, one was found not to be infringed, but the jury found the second patent to be infringed by a limited number of the Company's products, although the jury further found the Company did not induce infringement by any customers, including customers outside the United States. On March 29, 2013, the District Court denied most of the parties' post-trial motions on liability but granted the Company's motion for judgment as a matter of law finding that Fairchild infringed another of the Company's patents. On April 25, 2013, the Court denied both parties' motions regarding the unenforceability of each other's patents. The Company intends to challenge adverse findings on appeal; nevertheless, the Company estimates that even if the verdict on Fairchild's patent were ultimately upheld, the sales potentially impacted would amount to only about 0.3% of the Company's revenues. The Company requested an injunction preventing further infringement of its own patents by Fairchild, and Fairchild requested an injunction as well. Following a hearing on the issue in June 2014, the Court denied Fairchild's request for an injunction against the Company and granted the Company's request for an injunction against Fairchild. On January 13, 2015, the District Court entered final judgment on the liability and validity issues discussed above, and both parties filed appeals with the Federal Circuit, for which briefing should be completed later this year. The Company is also seeking financial damages, as well as enhanced damages for willful infringement, issues to be decided in separate proceedings at a later date.

On June 28, 2004, the Company filed a complaint for patent infringement in the U.S. District Court, Northern District of California, against SG Corporation, a Taiwanese company, and its U.S. subsidiary. The Company's complaint alleged that certain integrated circuits produced by SG infringed and continue to infringe certain of its patents. On June 10, 2005, in response to the initiation of the International Trade Commission (ITC) investigation discussed above, the District Court stayed all proceedings. Subsequent to the completion of the ITC proceedings, the District Court temporarily lifted the stay and scheduled a case management conference. On December 6, 2006, SG filed a notice of appeal of the ITC decision as discussed above. In response, and by agreement of the parties, the District Court vacated the scheduled case management conference and renewed the stay of proceedings pending the outcome of the Federal Circuit appeal of the ITC determination. On November 19, 2007, the Federal Circuit affirmed the ITC's findings in all respects, and SG did not file a petition for review. The parties subsequently filed a motion to dismiss the District Court case without prejudice. On November 4, 2009, the Company re-filed its complaint for patent infringement against SG and its parent corporations, Fairchild Semiconductor International, Inc. and Fairchild Semiconductor Corporation, to address their continued infringement of patents at issue in the original suit that recently emerged from SG requested reexamination proceedings before the U.S. Patent and Trademark Office (USPTO). The Company seeks, among other things, an order enjoining

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SG and Fairchild from infringing the Company's patents and an award of damages resulting from the alleged infringement. Fairchild has denied infringement and asked for a declaration from the Court that it does not infringe any Power Integrations patent, that the patents are invalid, and that one of the two of the Company's patents now at issue in the case is unenforceable. On May 5, 2010, SG and Fairchild filed an amended answer including counterclaims accusing the Company of infringing two patents, and since that time Fairchild has withdrawn its claim for infringement of one of the patents it originally asserted against the Company but added another patent to the case over the Company's objections; the Company contests these claims vigorously. Both parties filed summary judgment motions and challenges to each other’s experts’ testimony, and the Court granted the Company’s motion for summary judgment of non-infringement with respect to one of Fairchild’s two patents. Following a trial on the remaining claims in February 2014, the jury returned a verdict in the Company’s favor, affirming the validity of the asserted claims of the Company’s patents-in-suit, finding that SG and Fairchild infringed the Company’s asserted patents and induced infringement by others, and awarding $105.0 million in damages. Although the jury awarded damages, at this stage of the proceedings the Company cannot state the amount, if any, it might ultimately recover from Fairchild, and no benefits have been recorded in the Company’s condensed consolidated financial statements as a result of the damages verdict. The Jury also rejected Fairchild’s remaining counterclaims for infringement against the Company. Fairchild challenged these rulings in post-trial motions, but the judge confirmed the jury’s determinations on infringement and damages, although the Court declined to find Fairchild’s infringement willful. Fairchild also pressed its unenforceability claim with respect to one of the two patents it was found to infringe in post-trial briefing, but the Court rejected Fairchild’s unenforceability claim. Fairchild also requested reconsideration of the damages determinations, and the Court granted a new trial with respect to damages but none of the other issues addressed in the previous trial, with the retrial scheduled for December 2015. The parties recently completed pretrial proceedings challenging each other’s experts, and the Court granted portions of each party’s motions limiting the scope of expert testimony for purposes of the damages retrial, but neither party was successful in their efforts to prevent the other side’s experts from testifying at trial. Further pretrial proceedings will take place over the coming months.

In February 2010, Fairchild and System General ("SG") filed suits for patent infringement against the Company, Power Integrations Netherlands B.V., and representative offices of Power Integrations Netherlands in Shanghai and Shenzhen with the Suzhou Intermediate Court in the People's Republic of China. The suits assert four Chinese patents and seek an injunction and damages of approximately $19.0 million. Power Integrations Netherlands filed invalidation proceedings for all four asserted SG patents in the People's Republic of China Patent Reexamination Board (PRB) of the State Intellectual Property Office (SIPO), and all four challenges were accepted by the PRB, with hearings conducted in September 2010. In early January 2012, the Company received rulings from the PRB invalidating the majority of the claims Fairchild asserted in litigation. The Suzhou Court conducted evidentiary hearings in 2012 and issued rulings in late December 2012, finding that the Company did not infringe any of the asserted patents. Fairchild filed appeals challenging the Suzhou Court's non-infringement rulings, and the appeals court in Nanjing held further hearings in the infringement proceedings, but Fairchild has since dismissed its appeals, bringing the infringement proceedings to a close in the first quarter of 2015.

On July 11, 2011, the Company filed a complaint in the U.S. District Court, District of Columbia, against David Kappos in his capacity as Director of the United States Patent and Trademark Office (“PTO”) as part of the ongoing reexamination proceedings related to one of the patents asserted against Fairchild and SG in the Delaware litigation described above. The Company filed a motion for summary judgment on a preliminary jurisdictional issue, and the PTO filed a cross-motion to dismiss on this same issue; briefing on those motions was completed in October, 2011. On November 18, 2013, the Court granted the PTO’s motion and transferred the case to the Federal Circuit, where additional briefing took place. Following a hearing in May 2015, the Federal Circuit ruled in the Company's favor on August 12, 2015, overturning the PTO's claim construction and remanding the case for further proceedings.

On May 1, 2012, Fairchild Semiconductor Corporation and Fairchild's wholly-owned subsidiary, System General Corporation (referred to collectively as “Fairchild”), filed a complaint against the Company in the United States District Court for the District of Delaware. In its complaint, Fairchild alleged that the Company has infringed and is infringing four patents pertaining to power conversion integrated circuit devices. The Company answered Fairchild's complaint, denying infringement and asking for a declaration from the Court that it does not infringe any Fairchild patent and that the Fairchild patents are invalid, and the Company also asserted counterclaims against Fairchild for infringement of five of the Company's patents. Fairchild has withdrawn its claim for infringement of one of the patents it asserted against the Company after the Company's preliminary challenge. The parties streamlined their contentions in view of the Court's pretrial rulings, and following a trial in late May and early June 2015, a jury returned a verdict finding that Fairchild infringed one of the Company's patents, that Fairchild has induced and contributed to others' infringement of the Company's patent, and that the Company induced infringement of a Fairchild patent that was previously

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found infringed in the 2012 trial described above, with a damages award of $2.4 million in favor of Fairchild. However, in parallel proceedings the Patent Office has rejected all of the asserted claims of the one Fairchild patent found infringed, determinations that Fairchild is challenging on appeal, and the Court rejected Fairchild’s earlier request for an injunction based on those same claims. Both parties have filed post-trial motions and challenges to various portions of the jury verdicts, and the Court is expected to address the first wave of post-trial motions over the coming months. The Company believes it has valid defenses against the $2.4 million award in favor of Fairchild, and therefore has not recorded a loss in its financial statements at this time.

On October 21, 2015, the Company filed a complaint for patent infringement against Fairchild Semiconductor Corporation, Fairchild Semiconductor International, Inc., and wholly-owned subsidiary Fairchild (Taiwan) Corporation (referred to collectively as “Fairchild”) to address Fairchild’s continued infringement of two patents Fairchild was previously found to infringe in the three District Court cases the Company brought against Fairchild discussed above. In each of the three prior cases, Fairchild was found to infringe one of the patents at issue in the latest complaint, and Fairchild’s challenges to the validity of the patents were rejected during the course of the prior lawsuits as well.  Fairchild has not yet answered the complaint, and no trial date has been scheduled, but further proceedings are expected over the course of the coming months.

The Company is unable to predict the outcome of legal proceedings with certainty, and there can be no assurance that Power Integrations will prevail in the above-mentioned unsettled litigations. These litigations, whether or not determined in Power Integrations' favor or settled, will be costly and will divert the efforts and attention of the Company's management and technical personnel from normal business operations, potentially causing a material adverse effect on the business, financial condition and operating results. Currently, the Company is not able to estimate a loss or a range of loss for the ongoing litigation disclosed above, however adverse determinations in litigation could result in monetary losses, the loss of proprietary rights, subject the Company to significant liabilities, require Power Integrations to seek licenses from third parties or prevent the Company from licensing the technology, any of which could have a material adverse effect on the Company's business, financial condition and operating results.

13. RECENT ACCOUNTING PRONOUNCEMENTS:

In May 2014, the Financial Accounting Standards Board ("FASB") amended the existing accounting standards for revenue recognition, Accounting Standards Update ("ASU") 2014-09, Revenue from Contracts with Customers. The amendments are based on the principle that revenue should be recognized to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. The Company is required to adopt the amendments in the first quarter of 2018. Early adoption is permitted; however, the Company is not permitted to adopt the standard earlier than January 1, 2017. The amendments may be applied retrospectively to each prior period presented or retrospectively with the cumulative effect recognized as of the date of initial application. The Company is currently evaluating the impact of these amendments and the transition alternatives on its consolidated financial statements.

14. BANK LINE OF CREDIT:

On July 5, 2012, the Company entered into a Credit Agreement (the "Credit Agreement") with two banks. The Credit Agreement provides the Company with a $100.0 million revolving line of credit to use for general corporate purposes with a $20.0 million sublimit for the issuance of standby and trade letters of credit. The Credit Agreement was amended on April 1, 2014, to extend the Credit Agreement termination date from July 5, 2015, to April 1, 2017, with all other terms of the Credit Agreement remaining the same. The Company's ability to borrow under the revolving line of credit is conditioned upon the Company's compliance with specified covenants, including reporting and financial covenants, primarily a minimum cash requirement and a debt to earnings ratio, with which the Company is currently in compliance. All advances under the revolving line of credit will become due on April 1, 2017, or earlier in the event of a default. As of September 30, 2015, the Company had no letters of credit outstanding and no amount outstanding under the credit agreement.

15. INDEMNIFICATIONS:

The Company sells products to its distributors under contracts, collectively referred to as Distributor Sales Agreements (“DSA”). Each DSA contains the relevant terms of the contractual arrangement with the distributor, and generally includes certain

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POWER INTEGRATIONS, INC.

NOTES TO UNAUDITED CONDENSED CONSOLIDATED FINANCIAL STATEMENTS (Continued)

provisions for indemnifying the distributor against losses, expenses, and liabilities from damages that may be awarded against the distributor in the event the Company's products are found to infringe upon a patent, copyright, trademark, or other proprietary right of a third party (“Customer Indemnification”). The DSA generally limits the scope of and remedies for the Customer Indemnification obligations in a variety of industry-standard respects, including, but not limited to, limitations based on time and geography, and a right to replace an infringing product. The Company also, from time to time, has granted a specific indemnification right to individual customers.

The Company believes its internal development processes and other policies and practices limit its exposure related to such indemnifications. In addition, the Company requires its employees to sign a proprietary information and inventions agreement, which assigns the rights to its employees' development work to the Company. To date, the Company has not had to reimburse any of its distributors or customers for any losses related to these indemnifications and no material claims were outstanding as of September 30, 2015. For several reasons, including the lack of prior indemnification claims and the lack of a monetary liability limit for certain infringement cases, the Company cannot determine the maximum amount of potential future payments, if any, related to such indemnifications.

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ITEM 2. MANAGEMENT’S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND RESULTS OF OPERATIONS

The following discussion and analysis of our financial condition and results of operations should be read in conjunction with the condensed consolidated financial statements and the notes to those statements included elsewhere in this Quarterly Report on Form 10-Q, and with the consolidated financial statements and management's discussion and analysis of our financial condition and results of operations in our Annual Report on Form 10-K for the year ended December 31, 2014, filed with the SEC on February 10, 2015. This discussion contains forward-looking statements that involve risks and uncertainties. Our actual results could differ materially from those contained in these forward-looking statements due to a number of factors, including those discussed in Part II, Item 1A-“Risk Factors” and elsewhere in this report. See also “Cautionary Note Regarding Forward-Looking Statements” at the beginning of this report.

Overview

We design, develop and market analog and mixed-signal integrated circuits (ICs) and other electronic components and circuitry used in high-voltage power conversion. Our products are used in power converters that convert electricity from a high-voltage source (typically 48 volts or higher) to the type of power required for a specified downstream use. In most cases, this conversion entails, among other functions, converting alternating current (AC) to direct current (DC) or vice versa, reducing or increasing the voltage, and regulating the output voltage and/or current according to the customer's specifications.

A large percentage of our products are ICs used in AC-DC power supplies, which convert the high-voltage AC from a wall outlet to the low-voltage DC required by most electronic devices. Power supplies incorporating our products are used with all manner of electronic products including mobile phones, computers, entertainment and networking equipment, appliances, electronic utility meters, industrial controls and LED lights.

    Since our May 2012 acquisition of CT-Concept Technologie AG (Concept), we also offer IGBT drivers - circuit boards containing multiple ICs, electrical isolation components and other circuitry - used to operate arrays of high-voltage, high-power transistors known as IGBT modules. These driver/module combinations are used for power conversion in high-power applications (i.e., power levels ranging from tens of kilowatts up to one gigawatt) such as industrial motors, solar- and wind-power systems, electric vehicles and high-voltage DC transmission systems.

Our products bring a number of important benefits to the power-conversion market compared with less advanced alternatives, including reduced component count and design complexity, smaller size, higher reliability and reduced time-to-market. Our products also improve the energy efficiency of power converters, helping our customers meet the increasingly stringent efficiency standards that have been adopted around the world for many electronic products, and improving the efficacy of renewable-energy systems, electric vehicles and other high-power applications.

While the size of the power-supply market fluctuates with changes in macroeconomic conditions, the market has generally exhibited a modest growth rate over time as growth in the unit volumes of power supplies has largely been offset by reductions in the average selling price of components in this market. Therefore, the growth of our business depends primarily on our penetration of the power supply market, and our success in expanding the addressable market by introducing new products that address a wider range of applications. Our growth strategy includes the following elements:

• Increase the penetration of our ICs in the “low-power” AC-DC power supply market. The largest proportion of our revenues comes from power-supply applications requiring 50 watts of output or less. We continue to introduce more advanced products that make our IC-based solutions more attractive in this market. We have also increased the size of our sales and field-engineering staff considerably in recent years, and we continue to expand our offerings of technical documentation and design-support tools and services to help customers use our ICs. These tools and services include our PI Expert™ design software, which we offer free of charge, and our transformer-sample service.

• Increase the penetration of our products in higher-power applications. We believe we have developed and acquired technologies and products that enable us to bring the benefits of integration to applications requiring more than 50 watts of output. These include such applications as main power supplies for flat-panel TVs, desktop PCs, game

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consoles and, by virtue of our acquisition of Concept, IGBT-driver applications such as industrial motors, renewable energy systems and electric vehicles.

• Capitalize on the growing demand for more energy-efficient electronic products and lighting technologies, and for cleaner energy and transportation technologies. We believe that energy-efficiency is becoming an increasingly important design criterion for power supplies due largely to the emergence of standards and specifications that encourage, and in some cases mandate, the design of more energy-efficient electronic products. (For example, in 2008 the U.S. Department of Energy implemented mandatory federal standards governing the efficiency of external power supplies; these standards are scheduled to be tightened in 2016.) Power supplies incorporating our ICs are generally able to comply with all known efficiency specifications currently in effect, including the pending new U.S. federal standards mentioned above.

Additionally, technological advances combined with regulatory and legislative actions are resulting in the adoption of alternative lighting technologies such as LEDs. We believe this presents a significant opportunity for us because our ICs are used in driver (i.e. power-supply) circuitry for high-voltage LED lighting applications. Finally, the growing desire for less carbon-intensive sources of energy and modes of transportation represents an opportunity for us since our IGBT drivers are used in renewable-energy systems as well as electric trains and electric vehicles.

Our quarterly operating results are difficult to predict and subject to significant fluctuations. We plan our production and inventory levels based on internal forecasts of projected customer demand, which are highly unpredictable and can fluctuate substantially. Customers typically may cancel or reschedule orders on short notice without significant penalty and, conversely, often place orders with very short lead times to delivery. Also, external factors such as global economic conditions and supply-chain dynamics can cause our operating results to be volatile. Furthermore, because our industry is intensely price-sensitive, our gross margin (gross profit divided by net revenues) is subject to change based on the relative pricing of solutions that compete with ours. Variations in product mix, end-market mix and customer mix can also cause our gross margin to fluctuate. Because we purchase a large percentage of our silicon wafers from foundries located in Japan, our gross margin is influenced by fluctuations in the exchange rate between the U.S. dollar and the Japanese yen. Changes in the prices of raw materials used in our products, such as copper and gold, can also affect our gross margin. Although our wafer-fabrication and assembly operations are outsourced, as are most of our test operations, a portion of our production costs are fixed in nature. As a result, our unit costs and gross margin are impacted by the volume of units we produce.

Recent Results

Our net revenues were $88.9 million and $90.1 million in the three months ended September 30, 2015 and 2014, respectively and $256.7 million and $262.2 million in the nine months ended September 30, 2015 and 2014, respectively. The decrease in revenues for both the three and nine month periods was due primarily to lower unit sales into the computer end-market, reflecting reduced demand for power supplies for desktop computers, and the industrial end-market, reflecting a broad-based slowdown in demand from the industrial sector of the economy. These reductions were partially offset by higher unit sales into the communications end-market, driven by increased sales into mobile-device chargers and by our acquisition of CamSemi, whose products are used primarily in the communications end-market. Our top ten customers, including distributors that resell to OEMs and merchant power supply manufacturers, accounted for 64% and 61% of our net revenues in the three and nine months ended September 30, 2015, respectively, and 59% in each of the corresponding periods of 2014. Our top customer, a distributor of our products, accounted for approximately 20% and 21% of our net revenues in the three and nine months ended September 30, 2015, respectively, and 19% and 20% in the corresponding periods of 2014. International sales accounted for 95% and 96% of our net revenues in the three months ended September 30, 2015 and 2014, respectively, and 95% in both the nine months ended September 30, 2015 and 2014.

Our gross margin was 49.7% and 54.4% in the three months ended September 30, 2015 and 2014, respectively, and 50.8% and 54.8% in the nine months ended September 30, 2015 and 2014, respectively. The decrease in gross margin for the three and nine months ended September 30, 2015, compared with the same periods in the prior year was due primarily to an unfavorable change in end-market mix, with a greater percentage of revenue coming from lower-margin end-markets. In addition, we incurred higher period costs resulting from the amortization of intangibles and, with respect to the nine month period, inventory write-up related to our acquisition of CamSemi, which took place in the first quarter of 2015 (refer to Note 10, Acquisitions, in our Notes to Unaudited Condensed Consolidated Financial Statements, for details).

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Total operating expenses were $32.4 million and $32.2 million in the three months ended September 30, 2015 and 2014, respectively, and $102.5 million and $99.8 million in the nine months ended September 30, 2015 and 2014, respectively. The year-over-year increase was due primarily to increased headcount in research and development as a result of our acquisition of CamSemi, which increased payroll and related expenses. In addition, with respect to the nine month period, the increase was partially offset by lower intangible asset amortization expense as our Concept trade name was fully amortized as of the second quarter of 2014, and lower advertising and promotional expenses in 2015.

Critical Accounting Policies and Estimates

The preparation of financial statements and related disclosures in conformity with accounting principles generally accepted in the United States of America (“U.S. GAAP”) requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosures of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. On an ongoing basis, we evaluate our estimates, including those listed below. We base our estimates on historical facts and various other assumptions that we believe to be reasonable at the time the estimates are made. Actual results could differ from those estimates.

Our critical accounting policies are as follows:

•revenue recognition;

•stock-based compensation;

•estimating write-downs for excess and obsolete inventory;

•income taxes;

•business combinations; and

•goodwill and intangible assets.

Our critical accounting policies are important to the portrayal of our financial condition and results of operations, and require us to make judgments and estimates about matters that are inherently uncertain. A brief description of these critical accounting policies is set forth below. For more information regarding our accounting policies, see Note 2, Summary of Significant Accounting Policies, in our Notes to Unaudited Condensed Consolidated Financial Statements.

Revenue recognition

Product revenues consist of sales to original equipment manufacturers ("OEM") merchant power supply manufacturers and distributors. Approximately 76% of our net product sales were made to distributors in the nine months ended September 30, 2015, and 75% in the twelve months ended December 31, 2014. We apply the provisions of Accounting Standard Codification (“ASC”) 605-10 (“ASC 605-10”) and all related appropriate guidance. Revenue is recognized when all of the following criteria have been met: (1) persuasive evidence of an arrangement exists, (2) delivery has occurred, (3) the price is fixed or determinable, and (4) collectability is reasonably assured. Customer purchase orders are generally used to determine the existence of an arrangement. Delivery is considered to have occurred when title and risk of loss have transferred to our customer. We evaluate whether the price is fixed or determinable based on the payment terms associated with the transaction and whether the sales price is subject to refund or adjustment. With respect to collectability, we perform credit checks for new customers and perform ongoing evaluations of our existing customers' financial condition and require letters of credit whenever deemed necessary.

Sales to international OEM customers and merchant power supply manufacturers that are shipped from our facility in California are pursuant to delivered at frontier ("DAF"), shipping terms. As such, title to the product passes to the customer when the shipment reaches the destination country and revenue is recognized upon the arrival of the product in that country. Sales to international OEMs and merchant power supply manufacturers for shipments from our facility outside of the United States are pursuant to EX Works ("EXW"), shipping terms, meaning that title to the product transfers to the customer upon shipment from our foreign warehouse. Shipments to OEMs and merchant power supply manufacturers in the Americas are pursuant to FOB point of origin shipping terms meaning that title is passed to the customer upon shipment. Revenue is recognized upon title transfer for sales to OEMs and merchant power supply manufacturers, assuming all other criteria for revenue recognition are met.

Sales to most distributors are made under terms allowing certain price adjustments and rights of return on our products held by the distributors. As a result of these rights, we defer the recognition of revenue and the costs of revenues derived from sales to distributors until our distributors report that they have sold our products to their customers. Our recognition of such distributor sell-through is based on point of sales reports received from the distributor, at which time the price is no longer subject to adjustment and is fixed, and the products are no longer subject to return to us except pursuant to warranty terms. The gross

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profit that is deferred upon shipment to the distributor is reflected as “deferred income on sales to distributors” in the accompanying consolidated balance sheets. The total deferred revenue as of September 30, 2015, and December 31, 2014, was approximately $28.4 million and $25.0 million, respectively. The total deferred cost as of September 30, 2015, and December 31, 2014, was approximately $11.9 million and $9.8 million, respectively.

Frequently, distributors need to sell at a price lower than the standard distribution price to win business. At the time the distributor invoices its customer, or soon thereafter, the distributor submits a “ship and debit” price adjustment claim to us to adjust the distributor's cost from the standard price to the pre-approved lower price. After we verify that the claim was pre-approved, a credit memo is issued to the distributor for the ship and debit claim. We maintain a reserve for these unprocessed claims and for estimated future ship and debit price adjustments. The reserve appears as a reduction to accounts receivable and deferred income on sales to distributors in our accompanying consolidated balance sheets. To the extent future ship and debit claims significantly exceed amounts estimated, there could be a material impact on the deferred revenue and deferred margin ultimately recognized. To evaluate the adequacy of our reserves, we analyze historical ship and debit payments and levels of inventory in the distributor channels.

Sales to certain of our distributors are made under terms that do not include rights of return or price concessions after the product is shipped to the distributor. Accordingly, product revenue is recognized upon shipment and title transfer assuming all other revenue recognition criteria are met.

Stock-based compensation

We apply the provisions of ASC 718-10, Share-Based Payment. Under the provisions of ASC 718-10, we recognize the fair value of stock-based compensation in our financial statements over the requisite service period of the individual grants, which generally equals a four-year vesting period. We use estimates of volatility, expected term, risk-free interest rate, dividend yield and forfeitures in determining the fair value of these awards and the amount of compensation expense to recognize. Changes in the estimated forfeiture rate could result in changes to our current compensation charges for historical grants.

Estimating write-downs for excess and obsolete inventory

When evaluating the adequacy of our valuation adjustments for excess and obsolete inventory, we identify excess and obsolete products and also analyze historical usage, forecasted production based on demand forecasts, current economic trends and historical write-offs. This write-down is reflected as a reduction to inventory in the consolidated balance sheets and an increase in cost of revenues. If actual market conditions are less favorable than our assumptions, we may be required to take additional write-downs, which could adversely impact our cost of revenues and operating results.

Income taxes

Income-tax expense is an estimate of current income taxes payable or refundable in the current fiscal year based on reported income before income taxes. Deferred income taxes reflect the effect of temporary differences and carryforwards that are recognized for financial reporting and income-tax purposes.

We account for income taxes under the provisions of ASC 740. Under the provisions of ASC 740, deferred tax assets and liabilities are recognized based on the differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases, utilizing the tax rates that are expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. We recognize valuation allowances to reduce any deferred tax assets to the amount that we estimate will more likely than not be realized based on available evidence and management's judgment. We limit the deferred tax assets recognized related to certain officers' compensation to amounts that we estimate will be deductible in future periods based upon Internal Revenue Code Section 162(m). In the event that we determine, based on available evidence and management judgment, that all or part of the net deferred tax assets will not be realized in the future, we would record a valuation allowance in the period the determination is made. In addition, the calculation of tax liabilities involves significant judgment in estimating the impact of uncertainties in the application of complex tax laws. Resolution of these uncertainties in a manner inconsistent with our expectations could have a material impact on our results of operations and financial position.

As of September 30, 2015, we maintain a full valuation allowance on our California and New Jersey deferred tax assets as we do not believe that it is more likely than not that the deferred tax assets will be fully realized. We also maintain a valuation allowance on capital losses for federal purposes and a valuation allowance with respect to our deferred tax assets relating to tax credits in Canada.

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In the quarter ended June 30, 2014, we settled with the IRS and closed out our tax examination for the years 2007 through 2009. The resolution of the audit resulted in a federal and state tax benefit of $2.8 million and $0.5 million, respectively, and was recorded in our 2014 financial statements.

Business combinations

The purchase price of an acquisition is allocated to the underlying assets acquired and liabilities assumed based upon their estimated fair values at the date of acquisition. To the extent the purchase price exceeds the fair value of the net identifiable tangible and intangible assets acquired and liabilities assumed, such excess is allocated to goodwill. We determine the estimated fair values after review and consideration of relevant information, including discounted cash flows, quoted market prices and estimates made by management. We adjust the preliminary purchase price allocation, as necessary, during the measurement period of up to one year after the acquisition closing date as we obtain more information as to facts and circumstances existing at the acquisition date impacting asset valuations and liabilities assumed. Acquisition-related costs are recognized separately from the acquisition and are expensed as incurred.

Goodwill and intangible assets

In accordance with ASC 350-10, Goodwill and Other Intangible Assets, we evaluate goodwill for impairment on an annual basis, or as other indicators of impairment emerge. The provisions of ASC 350-10 require that we perform a two-step impairment test. In the first step, we compare the implied fair value of our single reporting unit to its carrying value, including goodwill. If the fair value of our reporting unit exceeds the carrying amount no impairment adjustment is required. If the carrying amount of our reporting unit exceeds the fair value, step two will be completed to measure the amount of goodwill impairment loss, if any exists. If the carrying value of our single reporting unit's goodwill exceeds its implied fair value, then we record an impairment loss equal to the difference, but not in excess of the carrying amount of the goodwill. Under the amendments of ASC 350-10, ASU 2011-08, Testing Goodwill for Impairment, we have the option to first assess qualitative factors to determine whether the existence of events or circumstances leads to a determination that it is more likely than not that the fair value of a reporting unit is less than its carrying amount. If we elect this option, and after assessing the totality of events or circumstances we determine it is not more likely than not that the fair value of a reporting unit is less than its carrying amount, then performing the two-step impairment test is unnecessary. We have not elected this option to date. As part of our annual impairment evaluation, we reviewed goodwill for impairment in the fourth quarter 2014, and concluded that no impairment existed as of December 31, 2014. Additionally, no impairment indicators have been identified during the nine months ended September 30, 2015.

ASC 350-10 also requires that intangible assets with estimable useful lives be amortized over their respective estimated useful lives, and reviewed for impairment in accordance with ASC 360-10, Accounting for the Impairment or Disposal of Long-Lived Assets. We review long-lived assets, such as acquired intangibles, in-process research and development and property and equipment, for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. We measure recoverability of assets to be held and used by a comparison of the carrying amount of an asset to estimated undiscounted future cash flows expected to be generated by the asset. If the carrying amount of an asset exceeds its estimated future cash flows, we recognize an impairment charge by the amount by which the carrying amount of the asset exceeds the fair value of the asset.

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Results of Operations

The following table sets forth certain operating data as a percentage of net revenues for the periods indicated.

	Three Months Ended September 30				Nine Months Ended September 30
	2015		2014		2015		2014
Net revenues	100.0	%	100.0	%	100.0	%	100.0	%
Cost of revenues	50.3		45.6		49.2		45.2
Gross profit	49.7		54.4		50.8		54.8
Operating expenses:
Research and development	15.6		14.9		17.0		15.8
Sales and marketing	12.5		12.8		13.9		13.7
General and administrative	8.3		7.9		9.0		8.6
Total operating expenses	36.4		35.6		39.9		38.1
Income from operations	13.3		18.8		10.9		16.7
Other income:
Other income, net	0.5		0.4		0.1		0.3
Income before income taxes	13.7		19.2		11.0		17.0
Provision for (benefit from) income taxes	0.8		1.3		0.7		(0.2	)
Net income	12.9	%	17.9	%	10.3	%	17.2	%

Comparison of the Three and Nine Months Ended September 30, 2015 and 2014

Net revenues. Net revenues consist of revenues from product sales, which are calculated net of returns and allowances. Net revenues for the three and nine months ended September 30, 2015 were $88.9 million and $256.7 million, respectively, and $90.1 million and $262.2 million, respectively, for the corresponding periods of 2014. The decrease in revenues for both the three and nine month periods was due primarily to lower unit sales into the computer end-market, reflecting reduced demand for power supplies for desktop computers, and the industrial end-market, reflecting a broad-based slowdown in demand from the industrial sector of the economy. These reductions were partially offset by higher unit sales into the communications end-market, driven by increased sales into mobile-device chargers and by our acquisition of CamSemi, whose products are used primarily in the communications end-market.

Our revenue mix by end market for the three and nine month periods ended September 30, 2015, compared to the corresponding periods in 2014, were as follows:

	Three Months Ended September 30				Nine Months Ended September 30
End Market	2015		2014		2015		2014
Communications	26	%	18	%	23	%	17	%
Computer	7	%	11	%	7	%	11	%
Consumer	36	%	36	%	37	%	37	%
Industrial	31	%	35	%	33	%	35	%

International sales, consisting of sales outside of the United States based on “ship to” customer locations, were $84.7 million and $244.2 million, respectively, in the three and nine months ended September 30, 2015, and $86.2 million and $250.1 million, respectively, in the corresponding periods of 2014. Although power converters using our products are distributed to end markets worldwide, most are manufactured in Asia. As a result, sales to this region represented 80% and 79% of our net revenues in the three and nine months ended September 30, 2015, and 80% of revenue in each of the corresponding periods of 2014. We expect international sales, and sales to the Asia region in particular, to continue to account for a large portion of our net revenues in the future.

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Sales to distributors accounted for 75% and 76% of net revenues in the three and nine months ended September 30, 2015, and 74% and 76% in the corresponding periods of 2014. Direct sales to OEMs and power-supply manufacturers accounted for the remainder.

One customer, a distributor of our products, accounted for more than 10% of our net revenues in the three and nine months ended September 30, 2015, and in the corresponding periods of 2014, while a second customer, also a distributor, accounted for more than 10% of our net revenues in the three months ended September 30, 2015, as shown in the following table:

	Three Months Ended September 30				Nine Months Ended September 30
Customer	2015		2014		2015		2014
Avnet	20	%	19	%	21	%	20	%
Powertech Distribution Ltd.	11	%	*		*		*

________________                        

* Total customer percentage of revenues was less than 10%.

No other customers accounted for 10% or more of our net revenues in these periods.

Gross profit. Gross profit is net revenues less cost of revenues. Our cost of revenues consists primarily of costs associated with the purchase of wafers from our contracted foundries, the assembly, packaging and testing of our products by sub-contractors, product testing performed in our own facilities, amortization of acquired intangible assets, and overhead associated with the management of our supply chain. Gross margin is gross profit divided by net revenues. The table below compares gross profit and gross margin for the three and nine months ended September 30, 2015 and 2014:

	Three Months Ended September 30						Nine Months Ended September 30
(dollars in millions)	2015			2014			2015			2014
Net revenues	$	88.9		$	90.1		$	256.7		$	262.2
Gross profit	$	44.2		$	49.1		$	130.5		$	143.8
Gross margin	49.7		%	54.4		%	50.8		%	54.8		%

The decrease in gross margin for the three and nine months ended September 30, 2015, compared with the same periods in the prior year, was due primarily to an unfavorable change in end-market mix, with a greater percentage of revenue coming from lower-margin end-markets. In addition, we incurred higher period costs resulting from the amortization of intangibles and, with respect to the nine month period, inventory write-up related to our acquisition of CamSemi, which took place in the first quarter of 2015 (refer to Note 10, Acquisitions, in our Notes to Unaudited Condensed Consolidated Financial Statements, for details).

Research and development expenses. Research and development ("R&D") expenses consist primarily of employee-related expenses, including stock-based compensation, and expensed material and facility costs associated with the development of new technologies and new products. We also record R&D expenses for prototype wafers related to new products until such products are released to production. The table below compares R&D expenses for the three and nine months ended September 30, 2015 and 2014:

	Three Months Ended September 30						Nine Months Ended September 30
(dollars in millions)	2015			2014			2015			2014
Net revenues	$	88.9		$	90.1		$	256.7		$	262.2
R&D expenses	$	13.9		$	13.5		$	43.7		$	41.3
R&D expenses as a % of net revenue	15.6		%	14.9		%	17.0		%	15.8		%

R&D expenses increased in the three and nine months ended September 30, 2015, compared to the same periods in 2014. The increase was due primarily to the addition of employees in connection with our acquisition of CamSemi (refer to Note 10, Acquisitions, in our Notes to Unaudited Condensed Consolidated Financial Statements, for details); the increase in headcount

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caused a corresponding increase in salary and other employee-related expenses. The increase for the three-month period was partially offset by decreased engineering-materials expenses.

Sales and marketing expenses. Sales and marketing ("S&M") expenses consist primarily of employee-related expenses, including stock-based compensation, commissions to sales representatives, amortization of intangible assets and facilities expenses, including expenses associated with our regional sales and support offices.

The table below compares S&M expenses for the three and nine months ended September 30, 2015 and 2014:

	Three Months Ended September 30						Nine Months Ended September 30
(dollars in millions)	2015			2014			2015			2014
Net revenues	$	88.9		$	90.1		$	256.7		$	262.2
S&M expenses	$	11.1		$	11.6		$	35.7		$	35.9
S&M expenses as a % of net revenue	12.5		%	12.8		%	13.9		%	13.7		%

S&M expenses decreased in the three months ended September 30, 2015, compared to the same period in 2014. The decrease was due primarily to lower bonus and commission expenses in 2015. S&M expenses in the nine months ended September 30, 2015 were relatively flat as compared to the same period in 2014.

General and administrative expenses. General and administrative ("G&A") expenses consist primarily of employee-related expenses, including stock-based compensation expenses, for administration, finance, human resources and general management, as well as consulting, professional services, legal and audit expenses. The table below compares G&A expenses for the three and nine months ended September 30, 2015 and 2014:

	Three Months Ended September 30						Nine Months Ended September 30
(dollars in millions)	2015			2014			2015			2014
Net revenues	$	88.9		$	90.1		$	256.7		$	262.2
G&A expenses	$	7.4		$	7.2		$	23.1		$	22.6
G&A expenses as a % of net revenue	8.3		%	7.9		%	9.0		%	8.6		%

G&A expenses in the three months ended September 30, 2015, were relatively flat as compared to the same period in 2014. G&A expenses increased in the nine months ended September 30, 2015, compared to the same period in 2014, due primarily to increased legal expenses as a result of higher patent-litigation fees in connection with our Fairchild litigation, partially offset by lower patent attorney spending.

Other income, net. Other income, net consists primarily of interest income earned on cash and cash equivalents, marketable securities and other investments, and foreign exchange gains or losses. The table below compares other income, net for the three and nine months ended September 30, 2015 and 2014:

	Three Months Ended September 30						Nine Months Ended September 30
(dollars in millions)	2015			2014			2015			2014
Net revenues	$	88.9		$	90.1		$	256.7		$	262.2
Other income, net	$	0.4		$	0.4		$	0.2		$	0.8
Other income, net as a % of net revenue	0.5		%	0.4		%	0.1		%	0.3		%

Other income, net decreased in the nine months ended September 30, 2015, compared to the same period in 2014 due primarily to the unfavorable impact of foreign currency movements relative to the U.S. dollar and the related loss recognized from the re-measurement of monetary foreign currency assets and liabilities of our Swiss subsidiary.

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Provision for (benefit from) income taxes. Provision for (benefit from) income taxes represents federal, state and foreign taxes. The table below compares income-tax expense (benefit) for the three and nine months ended September 30, 2015 and 2014:

	Three Months Ended September 30						Nine Months Ended September 30
(dollars in millions)	2015			2014			2015			2014
Income before income taxes	$	12.2		$	17.3		$	28.2		$	44.8
Provision for (benefit from) income taxes	$	0.7		$	1.1		$	1.7		$	(0.4	)
Effective tax rate	5.7		%	6.6		%	6.1		%	(0.9		)%

Our effective tax rates for the three and nine months ended September 30, 2015, were 5.7% and 6.1%, respectively. In the three and nine months ended September 30, 2015, the effective tax rates were lower than the statutory federal income-tax rate of 35% primarily due to the beneficial impact of the geographic distribution of our world-wide earnings.

In the three months ended September 30, 2014, our effective tax rate of 6.6% was lower than the statutory federal income-tax rate of 35%, primarily due to the beneficial impact of the geographic distribution of our world-wide earnings. In the quarter ended June 30, 2014, we reached an agreement with the IRS to conclude the examination of our income tax returns for the years 2007 through 2009. As a result, our provision for income tax in the second quarter of 2014 included a one-time benefit of $3.3 million comprising $2.8 million in federal income taxes and interest, and state income taxes of approximately $0.5 million. The one-time benefit includes the reversal of $4.1 million of related unrecognized tax benefits that had been recorded as non-current liabilities in our consolidated balance sheets. Reflecting the net impact of the benefit, our effective tax rate for the nine months ended September 30, 2014 was (0.9)%.

Liquidity and Capital Resources

As of September 30, 2015, we had $151.0 million in cash, cash equivalents and short-term marketable securities, a decrease of approximately $24.3 million from $175.3 million as of December 31, 2014. As of September 30, 2015, we had working capital, defined as current assets less current liabilities, of $168.1 million, a decrease of approximately $42.7 million from $210.8 million as of December 31, 2014.

On July 5, 2012, we entered into a credit agreement (the "Credit Agreement") with two banks. The Credit Agreement provides us with a $100.0 million revolving line of credit to use for general corporate purposes with a $20.0 million sub-limit for the issuance of standby and trade letters of credit. The Credit Agreement was amended on April 1, 2014, to extend the Credit Agreement termination date from July 5, 2015 to April 1, 2017, with all other terms of the Credit Agreement remaining the same. Our ability to borrow under the revolving line of credit is conditioned upon our compliance with specified covenants, primarily a minimum cash requirement and a debt-to-earnings ratio, with which we are currently in compliance. The Credit Agreement terminates on April 1, 2017, and all advances under the revolving line of credit will become due on such date, or earlier in the event of a default. As of September 30, 2015, we had no amounts outstanding under our agreement.

Operating activities generated cash of $67.4 million in the nine months ended September 30, 2015. Net income for this period was $26.4 million; we also incurred non-cash depreciation, amortization and stock-based compensation expenses of $12.2 million, $5.2 million and $11.5 million, respectively. Significant changes in assets and liabilities included a $10.0 million decrease in inventory due to ongoing reduction efforts and a $4.3 million decrease in prepaid expenses and other assets due primarily to a decrease in prepaid legal fees and income tax refunds received during the period. These increases in cash were partially offset by a $3.6 million decrease in accrued liabilities due to lower accrued professional fees and a $2.0 million decrease in accounts payable due primarily to the timing of payments.

Operating activities generated cash of $73.1 million in the nine months ended September 30, 2014. Net income for this period was $45.2 million; we also incurred non-cash depreciation, amortization and stock-based compensation expenses of $11.8 million, $4.7 million and $10.7 million, respectively. Significant changes in assets and liabilities included: (1) a $10.0 million decrease in prepaid expenses and other assets due primarily to a decrease in prepaid legal and prepaid income taxes; (2) a $3.0 million increase in deferred income on sales to distributors due to increased inventory levels at our distributors reflecting lower-than-expected sales in 2014; (3) a $2.5 million increase in accounts payable related primarily to the purchases of inventories and fixed assets; and (4) a $1.9 million decrease in accounts receivable due primarily to an increase in our reserve for ship and debit claims, resulting from higher of channel inventory. These items were partially offset by: (1) a $14.6 million increase in inventory,

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reflecting lower-than-expected sales in 2014; and (2) a $3.3 million decrease in taxes payable and accrued liabilities related primarily to the release of reserves attributable to our IRS settlement and the adoption of ASU 2013-11.

Our investing activities in the nine months ended September 30, 2015, resulted in a $11.0 million net use of cash, consisting primarily of $15.5 million in net cash paid for the acquisition of CamSemi, $10.4 million net cash paid for a building purchase (refer to Note 10, Acquisitions, in our Notes to Unaudited Condensed Consolidated Financial Statements, for details) and $7.6 million for purchases of property and equipment, primarily machinery and equipment for production. These uses of cash were partially offset by $22.5 million of proceeds from the sale and maturity of marketable securities, net of purchases. Our investing activities in the nine months ended September 30, 2014 resulted in a $63.9 million net use of cash, consisting primarily of $45.3 million for the purchases of marketable securities, $17.4 million for purchases of property and equipment, primarily machinery and equipment for production and research and development, and $1.3 million for the purchase of the domain name, www.power.com.

Our financing activities in the nine months ended September 30, 2015, resulted in a $57.3 million net use of cash. Financing activities consisted primarily of $53.7 million for the repurchase of our common stock and $10.5 million for the payment of dividends to stockholders, partially offset by proceeds of $6.9 million from the issuance of common stock, including the exercise of employee stock options and the issuance of shares through our employee stock purchase plan. Our financing activities in the nine months ended September 30, 2014 resulted in a $41.4 million net use of cash. Financing activities consisted primarily of $45.3 million for the repurchase of our common stock and $9.7 million for the payment of dividends to stockholders. This cash usage was offset by proceeds of $13.1 million from the issuance of common stock, including the exercise of employee stock options and the issuance of shares through our employee stock purchase plan.

In October 2013, our board of directors declared four quarterly cash dividends in the amount of $0.10 per share to be paid to stockholders of record at the end of each quarter in 2014. In April 2014, our board of directors increased the dividend payments for the third and fourth quarters of 2014 to $0.12 per share. A payout of approximately $3.0 million occurred on each of March 31, 2014, and June 30, 2014, and a payout of approximately $3.5 million occurred on each of September 30, 2014, and December 31, 2014. In January 2015, our board of directors extended the $0.12 quarterly dividend through each quarter in 2015. A dividend payout of approximately $3.5 million occurred on each of March 31, 2015, June 30, 2015 and September 30, 2015. The declaration of any future cash dividend is at the discretion of the board of directors and will depend on our financial condition, results of operations, capital requirements, business conditions and other factors, as well as a determination that cash dividends are in the best interests of our stockholders.

In October 2012, our board of directors authorized the use of $50.0 million for the repurchase of our common stock, and in the year ended December 31, 2014, and in July 2015, our board of directors authorized the use of an additional $75.0 million and $30.0 million, respectively, for repurchase of our common stock, with repurchases to be executed according to pre-defined price/volume guidelines. In the nine months ended September 30, 2015, we purchased approximately 1.3 million shares for $53.7 million, and in the nine months ended September 30, 2014, we purchased approximately 0.9 million shares for approximately $45.3 million. As of September 30, 2015, we had used up the amount authorized for repurchase. In October 2015, our board of directors authorized the use of an additional $30.0 million for the repurchase of our common stock. Authorization of future repurchase programs is at the discretion of the board of directors and will depend on our financial condition, results of operations, capital requirements, business conditions and other factors.

As of September 30, 2015, we had a contractual obligation related to income tax, which consisted primarily of unrecognized tax benefits of approximately $11.8 million. A portion of the tax obligation is classified as long-term income taxes payable and a portion is recorded in deferred tax assets in our condensed consolidated balance sheet. The settlement period for our income tax liabilities cannot be determined; however, they are not expected to be due within the next year.

There were no material changes in our contractual commitments from those reported in our Annual Report on Form 10-K for the year ended December 31, 2014.

Our cash, cash equivalents and investment balances may change in future periods due to changes in our planned cash outlays, including changes in incremental costs such as direct and integration costs related to future acquisitions. We expect continued sales growth in our foreign business and plan to use the earnings generated by our foreign subsidiaries to continue to fund both the working capital and growth needs of our foreign entities, along with providing funding for any future foreign acquisitions. We do not provide for U.S. taxes on our undistributed earnings of foreign subsidiaries that we intend to invest indefinitely outside the U.S., unless such taxes are otherwise required under U.S. tax law. Beginning in 2013, we determined that

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a portion of our foreign subsidiaries current and future earnings may be remitted prospectively to the U.S. for domestic cash flow purposes and, accordingly, provided for the related U.S. taxes in our consolidated financial statements. Currently the majority of our cash and marketable securities are held in the U.S. If we change our intent to invest our undistributed earnings outside the U.S. indefinitely or if a greater amount of undistributed earnings are needed for U.S. operations than previously anticipated and for which U.S. taxes have not been recorded, we would be required to accrue or pay U.S. taxes (subject to an adjustment for foreign tax credits, where applicable) and withholding taxes payable to various foreign countries on some or all of these undistributed earnings. As of December 31, 2014, we had undistributed earnings of foreign subsidiaries that are indefinitely invested outside of the U.S. of approximately $144.0 million.

If our operating results deteriorate during the remainder of 2015 as a result of a decrease in customer demand, pricing pressure, or other factors, our ability to generate positive cash flow from operations may be jeopardized. In that case, we may be forced to use our cash, cash equivalents and short-term investments, use our credit agreement or seek additional financing from third parties to fund our operations. We believe that cash generated from operations, together with existing sources of liquidity, will satisfy our projected working capital and other cash requirements for at least the next 12 months.

Off-Balance-Sheet Arrangements

As of September 30, 2015, we did not have any off-balance sheet arrangements or relationships with unconsolidated entities or financial partnerships, such as entities often referred to as structured finance or special purpose entities, which are typically established for the purpose of facilitating off-balance sheet arrangements or other contractually narrow or limited purposes.

Recent Accounting Pronouncements

In May 2014, the Financial Accounting Standards Board ("FASB") amended the existing accounting standards for revenue recognition, ASU 2014-09, Revenue from Contracts with Customers. The amendments are based on the principle that revenue should be recognized to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. We are required to adopt the amendments in the first quarter of 2018. Early adoption is permitted; however, we are not permitted to adopt the standard earlier than January 1, 2017. The amendments may be applied retrospectively to each prior period presented or retrospectively with the cumulative effect recognized as of the date of initial application. We are currently evaluating the impact of these amendments and the transition alternatives on our consolidated financial statements.

ITEM 3. QUANTITATIVE AND QUALITATIVE DISCLOSURES ABOUT MARKET RISK

There has not been a material change in our exposure to foreign currency exchange and interest rate risks from that described in our 2014 Annual Report on Form 10-K.

Interest Rate Risk. Our exposure to market risk for changes in interest rates relates primarily to our investment portfolio. We consider cash invested in highly liquid financial instruments with a remaining maturity of three months or less at the date of purchase to be cash equivalents. Investments in highly liquid financial instruments with maturities greater than three months at the date of purchase are classified as short-term investments. We generally hold securities until maturity; however, they may be sold under certain circumstances, including, but not limited to, when necessary for the funding of acquisitions and other strategic investments, and therefore we classify our investment portfolio as available-for-sale. We invest in high-credit quality issuers and, by policy, limit the amount of credit exposure to any one issuer. As stated in our policy, we seek to ensure the safety and preservation of our invested principal funds by limiting default risk, market risk and reinvestment risk. We mitigate default risk by investing in safe and high-credit quality securities and by constantly positioning our portfolio to respond appropriately to a significant reduction in a credit rating of any investment issuer, guarantor or depository. Our portfolio includes only marketable securities with active secondary or resale markets to facilitate portfolio liquidity. At September 30, 2015, and December 31, 2014, we held primarily cash equivalents and short-term investments with fixed interest rates.

Our investment securities are subject to market interest rate risk and will vary in value as market interest rates fluctuate. We monitor our investments per our above-mentioned investment policy; therefore, if market interest rates were to increase or decrease by 10% from interest rates as of September 30, 2015, or December 31, 2014, the increase or decrease in the fair market value of our portfolio on these dates would not have been material. We monitor our investments for impairment on a periodic basis. Refer to Note 2, Summary of Significant Accounting Policies, in our Notes to Unaudited Condensed Consolidated Financial Statements, for a tabular presentation of our available-for-sale investments and the expected maturity dates.

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Foreign Currency Exchange Risk. As of September 30, 2015, our primary transactional currency was U.S. dollars; in addition, we hold cash in Swiss francs and Euro. We maintain cash denominated in Swiss francs and Euro to fund the operations of our Swiss subsidiary. The foreign exchange rate fluctuation between the U.S. dollar versus the Swiss franc and Euro is recorded in other income in our condensed consolidated statements of income.

We have sales offices in various other foreign countries in which our expenses are denominated in the local currency, primary Asia and Western Europe. Cash balances held in foreign countries are subject to local banking laws and may bear higher or lower risk than cash deposited in the United States. From time to time we may enter into foreign currency hedging contracts to hedge certain foreign currency transactions. As of September 30, 2015, and December 31, 2014, we did not have an open foreign currency hedge program utilizing foreign currency forward exchange contracts.

Two of our major suppliers, Epson and Lapis, have wafer supply agreements based in U.S. dollars; however, our agreements with Epson and Lapis also allow for mutual sharing of the impact of the exchange rate fluctuation between Japanese yen and the U.S. dollar on future purchases. Each year, our management and these two suppliers review and negotiate future pricing; the negotiated pricing is denominated in U.S. dollars but is subject to contractual exchange rate provisions. The fluctuation in the exchange rate is shared equally between us and each of these suppliers on future purchases.

Nevertheless, as a result of our above-mentioned supplier agreements, our gross margin is influenced by fluctuations in the exchange rate between the U.S. dollar and the Japanese yen. All else being equal, a 10% change in the value of the U.S. dollar compared to the Japanese yen would result in a corresponding change in our gross margin of approximately 0.8% to 1.0%; this sensitivity may increase or decrease depending on the percentage of our wafer supply that we purchase from some of our Japanese suppliers and could subject our gross profit and operating results to the potential for material fluctuations.

ITEM 4. CONTROLS AND PROCEDURES

Limitation on Effectiveness of Controls

Any control system, no matter how well designed and operated, can provide only reasonable assurance as to the tested objectives. The design of any control system is based in part upon certain assumptions about the likelihood of future events, and there can be no assurance that any design will succeed in achieving its stated goals under all potential future conditions, regardless of how remote. The inherent limitations in any control system include the realities that judgments related to decision-making can be faulty, and that reduced effectiveness in controls can occur because of simple errors or mistakes. Due to the inherent limitations in a cost-effective control system, misstatements due to error may occur and may not be detected.

Evaluation of Disclosure Controls and Procedures

Management is required to evaluate our disclosure controls and procedures, as defined in Rule 13a-15(e) under the Securities Exchange Act of 1934 (the “Exchange Act”). Disclosure controls and procedures are controls and other procedures designed to provide reasonable assurance that information required to be disclosed in our reports filed under the Exchange Act, such as this Quarterly Report on Form 10-Q, is recorded, processed, summarized and reported within the time periods specified in the Securities and Exchange Commission's rules and forms. Disclosure controls and procedures include controls and procedures designed to provide reasonable assurance that such information is accumulated and communicated to our management, including our Chief Executive Officer and Chief Financial Officer as appropriate to allow timely decisions regarding required disclosure. Based on our management's evaluation (with the participation of our principal executive officer and principal financial officer), our principal executive officer and principal financial officer have concluded that our disclosure controls and procedures (as defined in Rules 13a-15(e) and 15d-15(e) under the Exchange Act) were effective as of the end of the period covered by this report.

Changes in Internal Control over Financial Reporting

There were no changes in our internal control over financial reporting during the quarter ended September 30, 2015, which were identified in connection with management's evaluation required by paragraph (d) of Rules 13a-15 and 15d-15 under the Exchange Act, that have materially affected or are reasonably likely to materially affect our internal control over financial reporting.

PART II. OTHER INFORMATION

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ITEM 1. LEGAL PROCEEDINGS

Information with respect to this item may be found in Note 12, Legal Proceedings and Contingencies, in our Notes to Unaudited Condensed Consolidated Financial Statements included in Part I, Item 1, of this Quarterly Report on Form 10-Q, which information is incorporated herein by reference.

ITEM 1A. RISK FACTORS

In addition to the other information in this report, the following factors should be considered carefully in evaluating our business before purchasing shares of our stock. The risks facing our business have not changed substantively from those discussed in our Annual Report on Form 10-K for the year ended December 31, 2014, except for the risk factor marked with an asterisk (*).

Our quarterly operating results are volatile and difficult to predict. If we fail to meet the expectations of public market analysts or investors, the market price of our common stock may decrease significantly. Our net revenues and operating results have varied significantly in the past, are difficult to forecast, are subject to numerous factors both within and outside of our control, and may fluctuate significantly in the future. As a result, our quarterly operating results could fall below the expectations of public market analysts or investors. If that occurs, the price of our stock may decline.

Some of the factors that could affect our operating results include the following:

• the demand for our products declining in the major end markets we serve, which may occur due to competitive factors, supply-chain fluctuations or changes in macroeconomic conditions;

• our products are sold through distributors, which limits our direct interaction with our end customers, which reduces our ability to forecast sales and increases the complexity of our business;

• competitive pressures on selling prices;

• the ability of our products to penetrate additional markets;

• the volume and timing of orders received from customers;

• the inability to adequately protect or enforce our intellectual property rights;

• expenses we are required to incur (or choose to incur) in connection with our intellectual property litigations;

• reliance on international sales activities for a substantial portion of our net revenues;

• fluctuations in exchange rates, particularly the exchange rate between the U.S. dollar and the Japanese yen, the Euro and the Swiss franc;

• the volume and timing of delivery of orders placed by us with our wafer foundries and assembly subcontractors, and their ability to procure materials;

• our ability to develop and bring to market new products and technologies on a timely basis;

• earthquakes, terrorists acts or other disasters;

• continued impact of changes in securities laws and regulations, including potential risks resulting from our evaluation of internal controls under the Sarbanes-Oxley Act of 2002;

• the lengthy timing of our sales cycle;

• undetected defects and failures in meeting the exact specifications required by our products;

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• audits by the Internal Revenue Service, and potential future changes in tax laws may increase the amount of taxes we are required to pay;

• our ability to attract and retain qualified personnel;

• risks associated with acquisitions and strategic investments;

• our ability to successfully integrate, or realize the expected benefits from, our acquisitions;

• changes in environmental laws and regulations, including with respect to energy consumption and climate change;

• interruptions in our information technology systems; and

• uncertainties arising out of economic consequences of current and potential military actions or terrorist activities and associated political instability.

If demand for our products declines in our major end markets, our net revenues will decrease. A limited number of applications of our products, such as cellphone chargers, LED lights, desktop PCs and home appliances make up a significant percentage of our net revenues. We expect that a significant level of our net revenues and operating results will continue to be dependent upon these applications in the near term. The demand for these products has been highly cyclical and has been impacted by economic downturns in the past. Any economic slowdown in the end markets that we serve could cause a slowdown in demand for our ICs. When our customers are not successful in maintaining high levels of demand for their products, their demand for our ICs decreases, which adversely affects our operating results. Any significant downturn in demand in these markets would cause our net revenues to decline and could cause the price of our stock to fall.

Our products are sold through distributors, which limits our direct interaction with our end customers, therefore reducing our ability to forecast sales and increasing the complexity of our business. Sales to distributors accounted for 76% of net revenues in the nine months ended September 30, 2015, and 75% in the twelve months ended December 31, 2014. Selling through distributors reduces our ability to forecast sales and increases the complexity of our business, requiring us to:

• manage a more complex supply chain;

• monitor the level of inventory of our products at each distributor and

• monitor the financial condition and credit-worthiness of our distributors, many of which are located outside of the United States and not publicly traded.

Since we have limited ability to forecast inventory levels at our end customers, it is possible that there may be significant build-up of inventories in the distributor channel, with the OEM or the OEM’s contract manufacturer. Such a buildup could result in a slowdown in orders, requests for returns from customers, or requests to move out planned shipments. This could adversely impact our revenues and profits. Any failure to manage these complexities could disrupt or reduce sales of our products and unfavorably impact our financial results.

Intense competition in the high-voltage power supply industry may lead to a decrease in our average selling price and reduced sales volume of our products. The high-voltage power supply industry is intensely competitive and characterized by significant price sensitivity. Our products face competition from alternative technologies, such as linear transformers, discrete switcher power supplies, and other integrated and hybrid solutions. If the price of competing solutions decreases significantly, the cost effectiveness of our products will be adversely affected. If power requirements for applications in which our products are currently utilized go outside the cost-effective range of our products, some of these alternative technologies can be used more cost effectively. In addition, as our patents expire, our competitors could legally begin using the technology covered by the expired patents in their products, potentially increasing the performance of their products and/or decreasing the cost of their products, which may enable our competitors to compete more effectively. Our current patents may or may not inhibit our competitors from getting any benefit from an expired patent. Our U.S. patents have expiration dates ranging from 2016 to 2033. We cannot assure that our products will continue to compete favorably or that we will be successful in the face of increasing competition from new products and enhancements introduced by existing competitors or new companies entering this market. We believe our failure to compete successfully in the high-voltage power supply business, including our ability to introduce new products with higher average selling prices, would materially harm our operating results.

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If our products do not penetrate additional markets, our business will not grow as we expect. We believe that our future success depends in part upon our ability to penetrate additional markets for our products. We cannot assure that we will be able to overcome the marketing or technological challenges necessary to penetrate additional markets. To the extent that a competitor penetrates additional markets before we do, or takes market share from us in our existing markets, our net revenues and financial condition could be materially adversely affected.

We do not have long-term contracts with any of our customers and if they fail to place, or if they cancel or reschedule orders for our products, our operating results and our business may suffer. Our business is characterized by short-term customer orders and shipment schedules, and the ordering patterns of some of our large customers have been unpredictable in the past and will likely remain unpredictable in the future. Not only does the volume of units ordered by particular customers vary substantially from period to period, but also purchase orders received from particular customers often vary substantially from early oral estimates provided by those customers for planning purposes. In addition, customer orders can be canceled or rescheduled without significant penalty to the customer. In the past, we have experienced customer cancellations of substantial orders for reasons beyond our control, and significant cancellations could occur again at any time. Also, a relatively small number of distributors, OEMs and merchant power supply manufacturers account for a significant portion of our revenues. Specifically, our top ten customers, including distributors, accounted for 61% of our net revenues in the nine months ended September 30, 2015, and 59% in the year ended December 31, 2014. However, a significant portion of these revenues are attributable to sales of our products through distributors of electronic components. These distributors sell our products to a broad, diverse range of end users, including OEMs and merchant power supply manufacturers, which mitigates the risk of customer concentration to a large degree.

If we are unable to adequately protect or enforce our intellectual property rights, we could lose market share, incur costly litigation expenses, suffer incremental price erosion or lose valuable assets, any of which could harm our operations and negatively impact our profitability. Our success depends upon our ability to continue our technological innovation and protect our intellectual property, including patents, trade secrets, copyrights and know-how. We are currently engaged in litigation to enforce our intellectual property rights, and associated expenses have been, and are expected to remain, material and have adversely affected our operating results. We cannot assure that the steps we have taken to protect our intellectual property will be adequate to prevent misappropriation, or that others will not develop competitive technologies or products. From time to time, we have received, and we may receive in the future, communications alleging possible infringement of patents or other intellectual property rights of others. Costly litigation may be necessary to enforce our intellectual property rights or to defend us against claimed infringement. The failure to obtain necessary licenses and other rights, and/or litigation arising out of infringement claims could cause us to lose market share and harm our business.

As our patents expire, we will lose intellectual property protection previously afforded by those patents. Additionally, the laws of some foreign countries in which our technology is or may in the future be licensed may not protect our intellectual property rights to the same extent as the laws of the United States, thus limiting the protections applicable to our technology.

If we do not prevail in our litigation, we will have expended significant financial resources, potentially without any benefit, and may also suffer the loss of rights to use some technologies.  We are currently involved in anumber of patent litigation matters and the outcome of the litigation is uncertain. See Note 12, Legal Proceedings and Contingencies, in our Notes to Unaudited Condensed Consolidated Financial Statements. For example, in one of our patent suits the infringing company has been found to infringe four of our patents. Despite the favorable court finding, the infringing party filed an appeal to the damages awarded. In another matter, we are being sued in an ongoing case for patent infringement. Should we ultimately be determined to be infringing another party's patents, or if an injunction is issued against us while litigation is pending on those claims, such result could have an adverse impact on our ability to sell products found to be infringing, either directly or indirectly. In the event of an adverse outcome, we may be required to pay substantial damages, stop our manufacture, use, sale, or importation of infringing products, or obtain licenses to the intellectual property we are found to have infringed.  We have also incurred, and expect to continue to incur, significant legal costs in conducting these lawsuits, including the appeal of the case we won, and our involvement in this litigation and any future intellectual property litigation could adversely affect sales and divert the efforts and attention of our technical and management personnel, whether or not such litigation is resolved in our favor.  Thus, even if we are successful in these lawsuits, the benefits of this success may fail to outweigh the significant legal costs we will have incurred.

Our international sales activities account for a substantial portion of our net revenues, which subjects us to substantial risks. Sales to customers outside of the United States of America account for, and have accounted for a large portion of our net revenues, including approximately 95% of our net revenues for the nine months ended September 30, 2015, and 95% for the year ended December 31, 2014. If our international sales declined and we were unable to increase domestic sales, our revenues would decline and our operating results would be harmed. International sales involve a number of risks to us, including: 

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• potential insolvency of international distributors and representatives;

• reduced protection for intellectual property rights in some countries;

• the impact of recessionary environments in economies outside the United States;

• tariffs and other trade barriers and restrictions;

• the burdens of complying with a variety of foreign and applicable U.S. Federal and state laws; and

• foreign-currency exchange risk.

Our failure to adequately address these risks could reduce our international sales and materially and adversely affect our operating results. Furthermore, because substantially all of our foreign sales are denominated in U.S. dollars, increases in the value of the dollar cause the price of our products in foreign markets to rise, making our products more expensive relative to competing products priced in local currencies.

Fluctuations in exchange rates, particularly the exchange rate between the U.S. dollar and the Japanese yen, Swiss franc and Euro, may impact our gross margin and net income. Our exchange rate risk related to the Japanese yen includes two of our major suppliers, Epson and Lapis, with which we have wafer supply agreements based in U.S. dollars; however, these agreements also allow for mutual sharing of the impact of the exchange rate fluctuation between Japanese yen and the U.S. dollar. Each year, our management and these suppliers review and negotiate pricing; the negotiated pricing is denominated in U.S. dollars but is subject to contractual exchange rate provisions. The fluctuation in the exchange rate is shared equally between Power Integrations and each of these suppliers. We completed the acquisition of Concept (located in Biel, Switzerland) in the second quarter of 2012. We maintain cash denominated in Swiss francs and euros to fund the operations of our Swiss subsidiary. The functional currency of our Swiss subsidiary is the U.S. dollar; gains and losses arising from the re-measurement of non-functional currency balances are recorded in other income in our consolidated statements of income, and material unfavorable exchange-rate fluctuations with the Swiss franc could negatively impact our net income.

* We depend on third-party suppliers to provide us with wafers for our products and if they fail to provide us sufficient quantities of wafers, our business may suffer. Our primary supply arrangements for the production of wafers are with Epson, Lapis, and X-FAB Silicon Foundries AG ("X-FAB"). Our contracts with these suppliers expire on varying dates, with the earliest to expire in April 2018. Although some aspects of our relationships with Lapis, X-FAB and Epson are contractual, many important aspects of these relationships depend on their continued cooperation. We cannot assure that we will continue to work successfully with Epson, Lapis and X-FAB in the future, and that the wafer foundries' capacity will meet our needs. Additionally, one or more of these wafer foundries could seek an early termination of our wafer supply agreements. Any serious disruption in the supply of wafers from Epson, Lapis and X-FAB could harm our business. We estimate that it would take 12 to 24 months from the time we identified an alternate manufacturing source to produce wafers with acceptable manufacturing yields in sufficient quantities to meet our needs.

Although we provide our foundries with rolling forecasts of our production requirements, their ability to provide wafers to us is ultimately limited by the available capacity of the wafer foundry. Any reduction in wafer foundry capacity available to us could require us to pay amounts in excess of contracted or anticipated amounts for wafer deliveries or require us to make other concessions to meet our customers' requirements, or may limit our ability to meet demand for our products. Further, to the extent demand for our products exceeds wafer foundry capacity, this could inhibit us from expanding our business and harm relationships with our customers. Any of these concessions or limitations could harm our business.

If our third-party suppliers and independent subcontractors do not produce our wafers and assemble our finished products at acceptable yields, our net revenues may decline. We depend on independent foundries to produce wafers, and independent subcontractors to assemble and test finished products, at acceptable yields and to deliver them to us in a timely manner. The failure of the foundries to supply us wafers at acceptable yields could prevent us from selling our products to our customers and would likely cause a decline in our net revenues and gross margin. In addition, our IC assembly process requires our manufacturers to use a high-voltage molding compound that has been available from only a few suppliers. These compounds and their specified processing conditions require a more exacting level of process control than normally required for standard IC packages.

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Unavailability of assembly materials or problems with the assembly process can materially and adversely affect yields, timely delivery and cost to manufacture. We may not be able to maintain acceptable yields in the future.

In addition, if prices for commodities used in our products increase significantly, raw material costs would increase for our suppliers which could result in an increase in the prices our suppliers charge us. To the extent we are not able to pass these costs on to our customers; this would have an adverse effect on our gross margins.

If our efforts to enhance existing products and introduce new products are not successful, we may not be able to generate demand for our products. Our success depends in significant part upon our ability to develop new ICs for high-voltage power conversion for existing and new markets, to introduce these products in a timely manner and to have these products selected for design into products of leading manufacturers. New product introduction schedules are subject to the risks and uncertainties that typically accompany development and delivery of complex technologies to the market place, including product development delays and defects. If we fail to develop and sell new products in a timely manner then our net revenues could decline.

In addition, we cannot be sure that we will be able to adjust to changing market demands as quickly and cost-effectively as necessary to compete successfully. Furthermore, we cannot assure that we will be able to introduce new products in a timely and cost-effective manner or in sufficient quantities to meet customer demand or that these products will achieve market acceptance. Our failure, or our customers' failure, to develop and introduce new products successfully and in a timely manner would harm our business. In addition, customers may defer or return orders for existing products in response to the introduction of new products. When a potential liability exists we will maintain reserves for customer returns, however we cannot assure that these reserves will be adequate.

In the event of an earthquake, terrorist act or other disaster, our operations may be interrupted and our business would be harmed. Our principal executive offices and operating facilities are situated near San Francisco, California, and most of our major suppliers, which are wafer foundries and assembly houses, are located in areas that have been subject to severe earthquakes, such as Japan. Many of our suppliers are also susceptible to other disasters such as tropical storms, typhoons or tsunamis. In the event of a disaster, such as the earthquake and tsunami in Japan, we or one or more of our major suppliers may be temporarily unable to continue operations and may suffer significant property damage. Any interruption in our ability or that of our major suppliers to continue operations could delay the development and shipment of our products and have a substantial negative impact on our financial results.

Securities laws and regulations, including potential risk resulting from our evaluation of internal controls under the Sarbanes-Oxley Act of 2002, will continue to impact our results. Complying with the requirements of the Sarbanes-Oxley Act of 2002 and NASDAQ's conditions for continued listing have imposed significant legal and financial compliance costs, and are expected to continue to impose significant costs and management burden on us. These rules and regulations also may make it more expensive for us to obtain director and officer liability insurance, and we may be required to accept reduced coverage or incur substantially higher costs to obtain coverage. These rules and regulations could also make it more difficult for us to attract and retain qualified executive officers and members of our board of directors, particularly qualified members to serve on our audit committee. Further, the rules and regulations under the Dodd-Frank Wall Street Reform and Consumer Protection Act, which became effective in 2011, may impose significant costs and management burden on us.

Additionally, because these laws, regulations and standards promulgated by the Sarbanes-Oxley Act and the Dodd-Frank Act are expected to be subject to varying interpretations, their application in practice may evolve over time as new guidance becomes available. This evolution may result in continuing uncertainty regarding compliance matters and additional costs necessitated by ongoing revisions to our disclosure and governance practices.

Because the sales cycle for our products can be lengthy, we may incur substantial expenses before we generate significant revenues, if any. Our products are generally incorporated into a customer's products at the design stage. However, customer decisions to use our products, commonly referred to as design wins, can often require us to expend significant research and development and sales and marketing resources without any assurance of success. These significant research and development and sales and marketing resources often precede volume sales, if any, by a year or more. The value of any design win will largely depend upon the commercial success of the customer's product. We cannot assure that we will continue to achieve design wins or that any design win will result in future revenues. If a customer decides at the design stage not to incorporate our products into its product, we may not have another opportunity for a design win with respect to that product for many months or years.

47

Our products must meet exacting specifications, and undetected defects and failures may occur which may cause customers to return or stop buying our products. Our customers generally establish demanding specifications for quality, performance and reliability, and our products must meet these specifications. ICs as complex as those we sell often encounter development delays and may contain undetected defects or failures when first introduced or after commencement of commercial shipments. We have from time to time in the past experienced product quality, performance or reliability problems. If defects and failures occur in our products, we could experience lost revenue, increased costs, including warranty expense and costs associated with customer support and customer expenses, delays in or cancellations or rescheduling of orders or shipments and product returns or discounts, any of which would harm our operating results.

Audits of our tax returns and potential future changes in tax laws may increase the amount of taxes we are required to pay. Our operations are subject to income and transaction taxes in the United States and in multiple foreign jurisdictions and to review or audit by the IRS and state, local and foreign tax authorities. In addition, the United States, countries in Asia and other countries where we do business have been considering changes in relevant tax, accounting and other laws, regulations and interpretations, including changes to tax laws applicable to multinational companies. These potential changes could adversely affect our effective tax rates or result in other costs to us.

We must attract and retain qualified personnel to be successful and competition for qualified personnel is intense in our market. Our success depends to a significant extent upon the continued service of our executive officers and other key management and technical personnel, and on our ability to continue to attract, retain and motivate qualified personnel, such as experienced analog design engineers and systems applications engineers. The competition for these employees is intense, particularly in Silicon Valley. The loss of the services of one or more of our engineers, executive officers or other key personnel could harm our business. In addition, if one or more of these individuals leaves our employ, and we are unable to quickly and efficiently replace those individuals with qualified personnel who can smoothly transition into their new roles, our business may suffer. We do not have long-term employment contracts with, and we do not have in place key person life insurance policies on, any of our employees.

We are exposed to risks associated with acquisitions and strategic investments. We have made, and in the future intend to make, acquisitions of, and investments in, companies, technologies or products in existing, related or new markets such as Concept. Acquisitions involve numerous risks, including but not limited to:

• inability to realize anticipated benefits, which may occur due to any of the reasons described below, or for other unanticipated reasons;

• the risk of litigation or disputes with customers, suppliers, partners or stockholders of an acquisition target arising from a proposed or completed transaction;

• impairment of acquired intangible assets and goodwill as a result of changing business conditions, technological advancements or worse-than-expected performance, which would adversely affect our financial results; and

• unknown, underestimated and/or undisclosed commitments, liabilities or issues not discovered in our due diligence of such transactions.

We also in the future may have strategic relationships with other companies, which may decline in value and/or not meet desired objectives. The success of these strategic relationships depends on various factors over which we may have limited or no control and requires ongoing and effective cooperation with strategic partners. Moreover, these relationships are often illiquid, such that it may be difficult or impossible for us to monetize such relationships.

Our inability to successfully integrate, or realize the expected benefits from, our acquisitions could adversely affect our results. We have made, and in the future intend to make, acquisitions of other businesses, such as Cambridge Semiconductor Limited and Concept, and with these acquisitions there is a risk that integration difficulties may cause us not to realize expected benefits. The success of the acquisitions could depend, in part, on our ability to realize the anticipated benefits and cost savings (if any) from combining the businesses of the acquired companies and our business, which may take longer to realize than expected.

Changes in environmental laws and regulations may increase our costs related to obsolete products in our existing inventory. Changing environmental regulations and the timetable to implement them continue to impact our customers' demand for our products. As a result there could be an increase in our inventory obsolescence costs for products manufactured prior to our customers' adoption of new regulations. Currently we have limited visibility into our customers' strategies to implement these

48

changing environmental regulations into their business. The inability to accurately determine our customers' strategies could increase our inventory costs related to obsolescence.

Interruptions in our information technology systems could adversely affect our business. We rely on the efficient and uninterrupted operation of complex information technology systems and networks to operate our business. Any significant system or network disruption, including but not limited to new system implementations, computer viruses, security breaches, or energy blackouts could have a material adverse impact on our operations, sales and operating results. We have implemented measures to manage our risks related to such disruptions, but such disruptions could still occur and negatively impact our operations and financial results. In addition, we may incur additional costs to remedy any damages caused by these disruptions or security breaches.

Uncertainties arising out of economic consequences of current and potential military actions or terrorist activities and associated political instability could adversely affect our business. Like other U.S. companies, our business and operating results are subject to uncertainties arising out of economic consequences of current and potential military actions or terrorist activities and associated political instability, and the impact of heightened security concerns on domestic and international travel and commerce. These uncertainties could also lead to delays or cancellations of customer orders, a general decrease in corporate spending or our inability to effectively market and sell our products. Any of these results could substantially harm our business and results of operations, causing a decrease in our revenues.

ITEM 2. UNREGISTERED SALES OF EQUITY SECURITIES AND USE OF PROCEEDS

In October 2012, our board of directors authorized the use of $50.0 million for the repurchase of our common stock. In the year ended December 31, 2014 and in July 2015, our board of directors authorized the use of an additional $75.0 million and $30.0 million, respectively, for repurchase of our common stock, with repurchases to be executed according to pre-defined price/volume guidelines. In the year ended December 31, 2014, we purchased 1.6 million shares for $80.8 million, and in the nine months ended September 30, 2015, we purchased approximately 1.3 million shares for $53.7 million. As of September 30, 2015, we had had used up the amount authorized for repurchase.

In October 2015, our board of directors authorized the use of an additional $30.0 million for the repurchase of our common stock. Authorization of future repurchase programs is at the discretion of the board of directors and will depend on our financial condition, results of operations, capital requirements, business conditions and other factors.

ISSUER PURCHASES OF EQUITY SECURITIES

The following table summarizes repurchases of our common stock during the third quarter of fiscal 2015:

Period	Total Number of Shares Purchased	Average Price Paid Per Share		Total Number of Shares Purchased as Part of Publicly Announced Plans or Programs	Approximate Dollar Value of Shares that May Yet be Repurchased Under the Plans or Programs (in millions)*
July 1, 2015, to July 31, 2015	12,437	$	44.77	12,437	$	30.0
August 1, 2015, to August 31, 2015	502,784	$	38.62	502,784	$	10.6
September 1, 2015, to September 30, 2015	259,736	$	40.75	259,736	$	—
Total	774,957			774,957

_______________

*     Excludes $30.0 million authorized in October 2015 for share repurchases.

ITEM 6. EXHIBITS

See the Exhibit Index immediately following the signature page to this Quarterly Report on Form 10-Q, which is incorporated by reference here.

49

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned thereunto duly authorized.

		POWER INTEGRATIONS, INC.
Dated:	October 29, 2015	By:	/s/ SANDEEP NAYYAR
			Sandeep Nayyar Chief Financial Officer (Duly Authorized Officer, Principal Financial Officer and Principal Accounting Officer)

50

INDEX TO EXHIBITS

EXHIBIT NUMBER	DESCRIPTION
3.1	Restated Certificate of Incorporation. (Filed with the SEC as Exhibit 3.1 to our Annual Report on Form 10-K filed on February 29, 2012, SEC File No. 000-23441.)
3.2	Amended and Restated Bylaws. (Filed with the SEC as Exhibit 3.1 to our Current Report on Form 8-K filed on April 26, 2013, SEC File No. 000-23441.)
4.1	Reference is made to Exhibits 3.1 to 3.2.
31.1	Certification of Chief Executive Officer pursuant to Section 302 of the Sarbanes-Oxley Act of 2002.
31.2	Certification of Chief Financial Officer pursuant to Section 302 of the Sarbanes-Oxley Act of 2002.
32.1	Certification of Chief Executive Officer pursuant to Section 906 of the Sarbanes-Oxley Act of 2002.**
32.2	Certification of Chief Financial Officer pursuant to Section 906 of the Sarbanes-Oxley Act of 2002.**
101.INS	XBRL Instance Document
101.SCH	XBRL Taxonomy Extension Schema Document
101.CAL	XBRL Taxonomy Extension Calculation Linkbase Document
101.DEF	XBRL Taxonomy Extension Definition Linkbase Document
101.LAB	XBRL Taxonomy Extension Label Linkbase Document
101.PRE	XBRL Taxonomy Extension Presentation Linkbase Document

All references in the table above to previously filed documents or descriptions are incorporating those documents and descriptions by reference thereto.

_____________

** The certifications attached as Exhibits 32.1 and 32.2 accompanying this Form 10-Q, are not deemed filed with the SEC, and are not to be incorporated by reference into any filing of Power Integrations, Inc. under the Securities Act of 1933, as amended, or the Securities Exchange Act of 1934, as amended, whether made before or after the date of this Form 10-Q, irrespective of any general incorporation language contained in such filing.

51

EX-31.1

Exhibit 31.1

CERTIFICATION OF CHIEF EXECUTIVE OFFICER

I, Balu Balakrishnan certify that:

1.I have reviewed this Form 10-Q of Power Integrations, Inc.;

2.Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to the period covered by this report;

3.Based on my knowledge, the financial statements, and other financial information included in this report, fairly present in all material respects the financial condition, results of operations and cash flows of the registrant as of, and for, the periods presented in this report;

4.The registrant's other certifying officer and I are responsible for establishing and maintaining disclosure controls and procedures (as defined in Exchange Act Rules 13a-15(e) and 15d-15(e)) and internal control over financial reporting (as defined in Exchange Act Rules 13a-15(f) and 15d-15(f)) for the registrant and have:

(a)Designed such disclosure controls and procedures, or caused such disclosure controls and procedures to be designed under our supervision, to ensure that material information relating to the registrant, including its consolidated subsidiaries, is made known to us by others within those entities, particularly during the period in which this report is being prepared;

(b)Designed such internal control over financial reporting, or caused such internal control over financial reporting to be designed under our supervision, to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles;

(c)Evaluated the effectiveness of the registrant's disclosure controls and procedures and presented in this report our conclusions about the effectiveness of the disclosure controls and procedures, as of the end of the period covered by this report based on such evaluation; and

(d)Disclosed in this report any change in the registrant's internal control over financial reporting that occurred during the registrant's most recent fiscal quarter (the registrant's fourth fiscal quarter in the case of an annual report) that has materially affected, or is reasonably likely to materially affect, the registrant's internal control over financial reporting; and

5.The registrant's other certifying officer and I have disclosed, based on our most recent evaluation of internal control over financial reporting, to the registrant's auditors and the audit committee of the registrant's board of directors (or persons performing the equivalent functions):

(a)All significant deficiencies and material weaknesses in the design or operation of internal control over financial reporting which are reasonably likely to adversely affect the registrant's ability to record, process, summarize and report financial information; and

(b)Any fraud, whether or not material, that involves management or other employees who have a significant role in the registrant's internal control over financial reporting.

Dated:	October 29, 2015	By:	/s/ BALU BALAKRISHNAN
			Balu Balakrishnan Chief Executive Officer

EX-31.2

Exhibit 31.2

CERTIFICATION OF CHIEF FINANCIAL OFFICER

I, Sandeep Nayyar, certify that:

1.I have reviewed this Form 10-Q of Power Integrations, Inc.;

2.Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to the period covered by this report;

3.Based on my knowledge, the financial statements, and other financial information included in this report, fairly present in all material respects the financial condition, results of operations and cash flows of the registrant as of, and for, the periods presented in this report;

4.The registrant's other certifying officer and I are responsible for establishing and maintaining disclosure controls and procedures (as defined in Exchange Act Rules 13a-15(e) and 15d-15(e)) and internal control over financial reporting (as defined in Exchange Act Rules 13a-15(f) and 15d-15(f)) for the registrant and have:

(a)Designed such disclosure controls and procedures, or caused such disclosure controls and procedures to be designed under our supervision, to ensure that material information relating to the registrant, including its consolidated subsidiaries, is made known to us by others within those entities, particularly during the period in which this report is being prepared;

(b)Designed such internal control over financial reporting, or caused such internal control over financial reporting to be designed under our supervision, to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles;

(c)Evaluated the effectiveness of the registrant's disclosure controls and procedures and presented in this report our conclusions about the effectiveness of the disclosure controls and procedures, as of the end of the period covered by this report based on such evaluation; and

(d)Disclosed in this report any change in the registrant's internal control over financial reporting that occurred during the registrant's most recent fiscal quarter (the registrant's fourth fiscal quarter in the case of an annual report) that has materially affected, or is reasonably likely to materially affect, the registrant's internal control over financial reporting; and

5.The registrant's other certifying officer and I have disclosed, based on our most recent evaluation of internal control over financial reporting, to the registrant's auditors and the audit committee of the registrant's board of directors (or persons performing the equivalent functions):

(a)All significant deficiencies and material weaknesses in the design or operation of internal control over financial reporting which are reasonably likely to adversely affect the registrant's ability to record, process, summarize and report financial information; and

(b)Any fraud, whether or not material, that involves management or other employees who have a significant role in the registrant's internal control over financial reporting.

Dated:	October 29, 2015	By:	/s/ SANDEEP NAYYAR
			Sandeep Nayyar Chief Financial Officer

EX-32.1

Exhibit 32.1

CERTIFICATION OF CHIEF EXECUTIVE OFFICER

CERTIFICATION PURSUANT TO 18 U.S.C. SECTION 1350, AS ADOPTED PURSUANT TO SECTION 906 OF

THE SARBANES-OXLEY ACT OF 2002

In connection with the Quarterly Report of Power Integrations, Inc. (the “Company”) on Form 10-Q for the quarter ended September 30, 2015, as filed with the Securities and Exchange Commission on the date hereof (the “Report”), I, Balu Balakrishnan, Chief Executive Officer of the Company, pursuant to 18 U.S.C. Section 1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002 (“Section 906”), certify to the best of my knowledge that:

(1)The Report fully complies with the requirements of Section 13(a) or Section 15(d) of the Securities Exchange Act of 1934; and

(2)The information contained in the Report fairly presents, in all material respects, the financial condition and results of operations of the Company.

Dated:	October 29, 2015	By:	/s/ BALU BALAKRISHNAN
			Balu Balakrishnan Chief Executive Officer

A signed original of this written statement required by Section 906, or other document authenticating, acknowledging, or otherwise adopting the signature that appears in typed form within the electronic version of this written statement required by Section 906, has been provided to the Registrant and will be retained by the Registrant and furnished to the Securities and Exchange Commission or its staff upon request.

EX-32.2

Exhibit 32.2

CERTIFICATION OF CHIEF FINANCIAL OFFICER

CERTIFICATION PURSUANT TO 18 U.S.C. SECTION 1350, AS ADOPTED PURSUANT TO SECTION 906 OF

THE SARBANES-OXLEY ACT OF 2002

In connection with the Quarterly Report of Power Integrations, Inc. (the “Company”) on Form 10-Q for the quarter ended September 30, 2015, as filed with the Securities and Exchange Commission on the date hereof (the “Report”), I, Sandeep Nayyar, Chief Financial Officer of the Company, pursuant to 18 U.S.C. Section 1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002 (“Section 906”), certify to the best of my knowledge that:

(1)The Report fully complies with the requirements of Section 13(a) or Section 15(d) of the Securities Exchange Act of 1934; and

(2)The information contained in the Report fairly presents, in all material respects, the financial condition and results of operations of the Company.

Dated:	October 29, 2015	By:	/s/ SANDEEP NAYYAR
			Sandeep Nayyar Chief Financial Officer

A signed original of this written statement required by Section 906, or other document authenticating, acknowledging, or otherwise adopting the signature that appears in typed form within the electronic version of this written statement required by Section 906, has been provided to the Registrant and will be retained by the Registrant and furnished to the Securities and Exchange Commission or its staff upon request.

XML

STOCK PLANS AND SHARE-BASED COMPENSATION (Option Activity) (Details) - Stock Options [Member] $ / shares in Units, shares in Thousands, $ in Thousands	9 Months Ended
	Sep. 30, 2015 USD ($) $ / shares shares
Option activity under the Plans
Outstanding at January 1, 2015 (in shares)	1,344
Granted (in shares)	0
Exercised (in shares)	(96)
Forfeited or expired (in shares)	(2)
Outstanding at September 30, 2015 (in shares)	1,246
Exercisable at September 30, 2015 (in shares)	1,228
Vested and expected to vest at September 30, 2015 (in shares)	1,246
Weighted- Average Exercise Price
Outstanding at beginning of period (in dollars per share) | $ / shares	$ 27.27
Granted (in dollars per share) | $ / shares	0.00
Exercised (in dollars per share) | $ / shares	25.29
Forfeited or expired (in dollars per share) | $ / shares	37.97
Outstanding at period end (in dollars per share) | $ / shares	27.39
Exercisable at period end (in dollars per share) | $ / shares	27.17
Vested and expected to vest at period end (in dollars per share) | $ / shares	$ 27.39
Weighted-Average Remaining Contractual Term (in years)
Outstanding, weighted-average remaining contractual term at period end	2 years 10 months 28 days
Exercisable, weighted-average remaining contractual term, at Period-end	2 years 10 months 10 days
Vested and expected to vest, weighted-average remaining contractual term, at period end	2 years 10 months 28 days
Aggregate Intrinsic Value (in thousands)
Outstanding, aggregate intrinsic value at period end | $	$ 18,463
Exercisable, aggregate intrinsic value, at period end | $	18,463
Vested and expected to vest, aggregate intrinsic value, at Period-end | $	$ 18,463

XML

BANK LINE OF CREDIT (Details)	Sep. 30, 2015 USD ($)	Jul. 05, 2012 USD ($) bank
Line of Credit Facility [Line Items]
Number of banks used for Credit Agreement | bank		2
Line of Credit [Member]
Line of Credit Facility [Line Items]
Credit Agreement, maximum borrowing capacity		$ 100,000,000
Letters of credit outstanding	$ 0
Credit agreement outstanding	$ 0
Line of credit sublimit for issuance of letters of credit [Member]
Line of Credit Facility [Line Items]
Credit Agreement, maximum borrowing capacity		$ 20,000,000

XML

SIGNIFICANT CUSTOMERS AND INTERNATIONAL SALES (Product Sales) (Details) - Product Concentration Risk [Member] - Sales Revenue, Goods, Net [Member]	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Communications [Member]
Revenue from External Customer [Line Items]
Concentration risk, percentage of total net revenues	26.00%	18.00%	23.00%	17.00%
Computer [Member]
Revenue from External Customer [Line Items]
Concentration risk, percentage of total net revenues	7.00%	11.00%	7.00%	11.00%
Consumer [Member]
Revenue from External Customer [Line Items]
Concentration risk, percentage of total net revenues	36.00%	36.00%	37.00%	37.00%
Industrial [Member]
Revenue from External Customer [Line Items]
Concentration risk, percentage of total net revenues	31.00%	35.00%	33.00%	35.00%

XML

SIGNIFICANT CUSTOMERS AND INTERNATIONAL SALES (Customer and Credit Risk Concentration) (Details)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2015 Customer	Sep. 30, 2014 Customer	Sep. 30, 2015 Segment Customer	Sep. 30, 2014 Customer	Dec. 31, 2014 Customer
Concentration Risk [Line Items]
Number of end-markets from which revenue is recognized | Segment			4
Sales Revenue, Goods, Net [Member] | Customer Concentration Risk [Member]
Concentration Risk [Line Items]
Number of major customers	1	1	1	1
Concentration risk percentage benchmark	10.00%	10.00%	10.00%	10.00%
Sales Revenue, Goods, Net [Member] | Customer Concentration Risk [Member] | Customer A [Member]
Concentration Risk [Line Items]
Concentration risk, percentage of total net revenues	20.00%	19.00%	21.00%	20.00%
Sales Revenue, Goods, Net [Member] | Customer Concentration Risk [Member] | Customer B [Member]
Concentration Risk [Line Items]
Concentration risk, percentage of total net revenues	11.00%
Sales Revenue, Goods, Net [Member] | Customer Concentration Risk [Member] | Ten Customers [Member]
Concentration Risk [Line Items]
Number of major customers	10	10	10	10
Concentration risk, percentage of total net revenues	64.00%	59.00%	61.00%	59.00%
Accounts Receivable [Member] | Credit Concentration Risk [Member]
Concentration Risk [Line Items]
Number of major customers			10		10
Concentration risk percentage benchmark for accounts receivable (more than)	10.00%		10.00%		10.00%
Accounts Receivable [Member] | Credit Concentration Risk [Member] | Customer A [Member]
Concentration Risk [Line Items]
Concentration risk percentage benchmark			23.00%		22.00%
Accounts Receivable [Member] | Credit Concentration Risk [Member] | Customer B [Member]
Concentration Risk [Line Items]
Concentration risk percentage benchmark			12.00%
Accounts Receivable [Member] | Credit Concentration Risk [Member] | Ten Customers [Member]
Concentration Risk [Line Items]
Concentration risk percentage benchmark			65.00%		66.00%
Accounts Receivable [Member] | Credit Concentration Risk [Member] | Customer Three [Member]
Concentration Risk [Line Items]
Concentration risk percentage benchmark					11.00%

XML

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Available-for-sale Investments) (Details) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 96,729	$ 114,492
Gross Unrealized Gains	78	128
Gross Unrealized Losses	(11)	(45)
Estimated Fair Market Value	96,796	114,575
Investments due in less than 3 months [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	27,419
Gross Unrealized Gains	1
Gross Unrealized Losses	0
Estimated Fair Market Value	27,420
Investments due in 4-12 months [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	64,306	30,233
Gross Unrealized Gains	72	36
Gross Unrealized Losses	(11)	0
Estimated Fair Market Value	64,367	30,269
Investments due in more than 12 months [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	5,004	84,259
Gross Unrealized Gains	5	92
Gross Unrealized Losses	0	(45)
Estimated Fair Market Value	5,009	84,306
Commercial paper [Member] | Investments due in less than 3 months [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	18,019
Gross Unrealized Gains	0
Gross Unrealized Losses	0
Estimated Fair Market Value	18,019
Corporate securities [Member] | Investments due in less than 3 months [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	9,400
Gross Unrealized Gains	1
Gross Unrealized Losses	0
Estimated Fair Market Value	9,401
Corporate securities [Member] | Investments due in 4-12 months [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	64,306	30,233
Gross Unrealized Gains	72	36
Gross Unrealized Losses	(11)	0
Estimated Fair Market Value	64,367	30,269
Corporate securities [Member] | Investments due in more than 12 months [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	5,004	84,259
Gross Unrealized Gains	5	92
Gross Unrealized Losses	0	(45)
Estimated Fair Market Value	$ 5,009	$ 84,306

XML

STOCK PLANS AND SHARE-BASED COMPENSATION (Tables)

9 Months Ended

Sep. 30, 2015

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Stock-based Compensation Expense

The following table summarizes the stock-based compensation expense recognized in accordance with ASC 718-10 for the three and nine months ended September 30, 2015, and September 30, 2014:

	Three Months Ended				Nine Months Ended
	September 30,				September 30,
(In thousands)	2015		2014		2015		2014
Cost of revenues	$	219	$	131	$	725	$	648
Research and development	1,277		971		3,974		3,522
Sales and marketing	877		779		2,767		2,578
General and administrative	988		699		4,036		3,922
Total stock-based compensation expense	$	3,361	$	2,580	$	11,502	$	10,670

Schedule of Unrecognized Compensation Expense for Unvested Awards

The following table summarizes total compensation expense related to unvested awards not yet recognized, net of expected forfeitures, and the weighted-average period over which it is expected to be recognized as of September 30, 2015:

	September 30, 2015
	Unrecognized Compensation Expense for Unvested Awards (in thousands)		Weighted Average Remaining Recognition Period (in years)
Options	$	296	0.57
Performance-based awards	189		0.25
Long-term performance-based awards	606		1.81
Restricted stock unit awards	24,049		2.46
Purchase plan	434		0.34
Total unrecognized compensation expense	$	25,574

Schedule of Share-based Payment Award, Employee Stock Purchase Plan, Valuation Assumptions

The fair value of employees’ stock purchase rights under the Purchase Plan was estimated using the Black-Scholes model with the following weighted-average assumptions:        

	Three Months Ended		Nine Months Ended
	September 30,		September 30,
	2015	2014	2015	2014
Risk-free interest rate	0.17%	0.05%	0.13%	0.05	%	-	0.07%
Expected volatility rate	26%	48%	29%	30	%	-	48%
Expected dividend yield	1.20%	0.85%	1.08%	0.66	%	-	0.85%
Expected term of purchase right (in years)	0.5	0.5	0.5	0.5
Weighted-average estimated fair value of purchase rights	$8.41	$15.25	$10.18	$14.40

Summary of Option Activity Under the Plans

A summary of stock option activity under the Plans, excluding PSUs, PRSUs and RSUs, as of September 30, 2015, and changes during the nine months then ended, is presented below:

	Shares (in thousands)		Weighted- Average Exercise Price	Weighted-Average Remaining Contractual Term (in years)	Aggregate Intrinsic Value (in thousands)
Outstanding at January 1, 2015	1,344		$27.27
Granted	—		—
Exercised	(96	)	$25.29
Forfeited or expired	(2	)	$37.97
Outstanding at September 30, 2015	1,246		$27.39	2.91	$	18,463
Exercisable at September 30, 2015	1,228		$27.17	2.86	$	18,463
Vested and expected to vest at September 30, 2015	1,246		$27.39	2.91	$	18,463

Performance Based Awards (PSUs) [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Schedule of Share-based Compensation, Restricted Stock Units Award Activity

A summary of PSUs outstanding as of September 30, 2015, and activity during the nine months then ended, is presented below:

	Shares (in thousands)		Weighted- Average Grant Date Fair Value Per Share	Weighted-Average Remaining Contractual Term (in years)	Aggregate Intrinsic Value (in thousands)
Outstanding at January 1, 2015	—		—
Granted	88		$52.39
Vested	—		—
Change in units due to performance achievement for PSUs vested in the year	—		—
Forfeited or expired	(1	)	$50.79
Outstanding at September 30, 2015	87		$52.41	0.25	$	3,684
Outstanding and expected to vest at September 30, 2015	12			0.25	$	516

Long-Term Performance-based Awards (PRSUs) [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Schedule of Share-based Compensation, Restricted Stock Units Award Activity

A summary of PRSUs outstanding as of September 30, 2015, and activity during the nine months then ended, is presented below:

	Shares (in thousands)		Weighted- Average Grant Date Fair Value Per Share	Weighted-Average Remaining Contractual Term (in years)	Aggregate Intrinsic Value (in thousands)
Outstanding at January 1, 2015	61		$55.51
Granted	72		$52.47
Vested	—		—
Forfeited or expired	(4	)	$57.76
Outstanding at September 30, 2015	129		$53.75	1.81	$	5,427
Outstanding and expected to vest at September 30, 2015	17			1.79	$	724

Restricted Stock Units (RSUs) [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Schedule of Share-based Compensation, Restricted Stock Units Award Activity

A summary of RSUs outstanding as of September 30, 2015, and changes during the nine months then ended, are as follows:

	Shares (in thousands)		Weighted- Average Grant Date Fair Value Per Share	Weighted-Average Remaining Contractual Term (in years)	Aggregate Intrinsic Value (in thousands)
Outstanding at January 1, 2015	692		$43.86
Granted	302		$49.90
Vested	(257	)	$42.49
Forfeited or expired	(48	)	$45.55
Outstanding at September 30, 2015	689		$46.90	1.46	$	29,073
Outstanding and expected to vest at September 30, 2015	636			1.40	$	26,804

XML

PROVISION FOR INCOME TAXES (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Jun. 30, 2014
Income Tax Disclosure [Abstract]
Effective income tax rate	5.70%	6.60%	6.10%	(0.90%)
Federal statutory tax rate	35.00%	35.00%	35.00%	35.00%
Operating Loss Carryforwards [Line Items]
Unrecognized Tax Benefits, Decrease Resulting from Settlements with Taxing Authorities				$ 4.1
Internal Revenue Service (IRS) [Member] | Tax Years 2007 through 2009 [Member]
Operating Loss Carryforwards [Line Items]
Income Tax Examination, Liability (Refund) Adjustment from Settlement with Taxing Authority					$ (3.3)
Domestic Tax Authority [Member] | Internal Revenue Service (IRS) [Member] | Tax Years 2007 through 2009 [Member]
Operating Loss Carryforwards [Line Items]
Income Tax Examination, Liability (Refund) Adjustment from Settlement with Taxing Authority					(2.8)
State and Local Jurisdiction [Member] | Internal Revenue Service (IRS) [Member] | Tax Years 2007 through 2009 [Member]
Operating Loss Carryforwards [Line Items]
Income Tax Examination, Liability (Refund) Adjustment from Settlement with Taxing Authority					$ (0.5)

XML

INVENTORIES (Details) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Inventory Disclosure [Abstract]
Raw materials	$ 18,661	$ 21,127
Work-in-process	14,659	14,643
Finished goods	22,119	28,255
Total	$ 55,439	$ 64,025

XML

STOCK PLANS AND SHARE-BASED COMPENSATION (Stock-Based Compensation) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Stock-based compensation expense for stock options, stock awards and employee stock purchases included in operations:
Stock-based compensation expense	$ 3,361	$ 2,580	$ 11,502	$ 10,670
Unrecognized Compensation Expense for Unvested Awards	25,574		25,574
Stock Options [Member]
Stock-based compensation expense for stock options, stock awards and employee stock purchases included in operations:
Stock-based compensation expense	100	200	500	1,000
Unrecognized Compensation Expense for Unvested Awards	296		$ 296
Weighted Average Remaining Recognition Period (in years)			6 months 25 days
Performance Based Awards (PSUs) [Member]
Stock-based compensation expense for stock options, stock awards and employee stock purchases included in operations:
Unrecognized Compensation Expense for Unvested Awards	189		$ 189
Weighted Average Remaining Recognition Period (in years)			3 months
Long-Term Performance-based Awards (PRSUs) [Member]
Stock-based compensation expense for stock options, stock awards and employee stock purchases included in operations:
Unrecognized Compensation Expense for Unvested Awards	606		$ 606
Weighted Average Remaining Recognition Period (in years)			1 year 9 months 22 days
Restricted Stock Units (RSUs) [Member]
Stock-based compensation expense for stock options, stock awards and employee stock purchases included in operations:
Stock-based compensation expense	3,200	2,800	$ 9,500	8,400
Unrecognized Compensation Expense for Unvested Awards	24,049		$ 24,049
Weighted Average Remaining Recognition Period (in years)			2 years 5 months 15 days
Employee Stock [Member]
Stock-based compensation expense for stock options, stock awards and employee stock purchases included in operations:
Stock-based compensation expense	300	400	$ 900	900
Unrecognized Compensation Expense for Unvested Awards	434		$ 434
Weighted Average Remaining Recognition Period (in years)			4 months 2 days
Cost of revenues [Member]
Stock-based compensation expense for stock options, stock awards and employee stock purchases included in operations:
Stock-based compensation expense	219	131	$ 725	648
Research and development [Member]
Stock-based compensation expense for stock options, stock awards and employee stock purchases included in operations:
Stock-based compensation expense	1,277	971	3,974	3,522
Sales and marketing [Member]
Stock-based compensation expense for stock options, stock awards and employee stock purchases included in operations:
Stock-based compensation expense	877	779	2,767	2,578
General and administrative [Member]
Stock-based compensation expense for stock options, stock awards and employee stock purchases included in operations:
Stock-based compensation expense	$ 988	$ 699	$ 4,036	$ 3,922

XML

ACQUISITIONS (Purchase Price and Estimated Fair Values) (Details) - USD ($) $ in Thousands	Sep. 30, 2015	Aug. 31, 2015	Jan. 02, 2015	Dec. 31, 2014
Assets Acquired
Goodwill	$ 91,849			$ 80,599
Cambridge Semiconductor Limited [Member]
Assets Acquired
Cash			$ 1,134
Accounts receivable			1,891
Inventories			1,409
Prepaid expenses and other current assets			408
Tax receivable			1,093
Intangible assets			9,020
Goodwill			11,250
Total assets acquired			26,205
Liabilities Assumed
Current liabilities			1,832
Taxes payable			1,090
Total liabilities assumed			2,922
Total purchase price			23,283
Cambridge Semiconductor Limited [Member] | Developed technology [Member]
Assets Acquired
Intangible assets			6,600
Cambridge Semiconductor Limited [Member] | Customer relationships [Member]
Assets Acquired
Intangible assets			$ 2,420
Building [Member]
Assets Acquired
Intangible assets		$ 700
Liabilities Assumed
Total liabilities assumed		$ 100

XML

SIGNIFICANT CUSTOMERS AND INTERNATIONAL SALES (International Sales) (Details) - Sales Revenue, Goods, Net [Member] - Geographic Concentration Risk [Member]	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Revenue from External Customers [Line Items]
Concentration risk, percentage of total net revenues	95.00%	96.00%	95.00%	95.00%
Hong Kong/China
Revenue from External Customers [Line Items]
Concentration risk, percentage of total net revenues	49.00%	47.00%	49.00%	46.00%
Taiwan
Revenue from External Customers [Line Items]
Concentration risk, percentage of total net revenues	15.00%	16.00%	14.00%	16.00%
Korea
Revenue from External Customers [Line Items]
Concentration risk, percentage of total net revenues	10.00%	11.00%	10.00%	11.00%
Western Europe (excluding Germany)
Revenue from External Customers [Line Items]
Concentration risk, percentage of total net revenues	11.00%	11.00%	11.00%	11.00%
Japan
Revenue from External Customers [Line Items]
Concentration risk, percentage of total net revenues	4.00%	5.00%	5.00%	5.00%
Germany
Revenue from External Customers [Line Items]
Concentration risk, percentage of total net revenues	3.00%	2.00%	3.00%	2.00%
Other
Revenue from External Customers [Line Items]
Concentration risk, percentage of total net revenues	3.00%	4.00%	3.00%	4.00%

XML

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

9 Months Ended

Sep. 30, 2015

Accounting Policies [Abstract]

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES:

No material changes have been made to the Company's significant accounting policies disclosed in Note 2, Summary of Significant Accounting Policies, in its Annual Report on Form 10-K, filed on February 10, 2015, for the year ended December 31, 2014. The accounting policy information below is to aid in the understanding of the financial information disclosed.

Cash and Cash Equivalents

The Company considers cash invested in highly liquid financial instruments with maturities of three months or less at the date of purchase to be cash equivalents.

Marketable Securities

The Company generally holds securities until maturity; however, they may be sold under certain circumstances including, but not limited to, when necessary for the funding of acquisitions, stock repurchases and other strategic investments. As a result the Company classifies its investment portfolio as available-for-sale. The Company classifies all investments with a maturity date greater than three months at the date of purchase as short-term marketable securities in its Condensed Consolidated Balance Sheets. As of September 30, 2015, and December 31, 2014, the Company's marketable securities consisted primarily of highly liquid corporate securities, commercial paper and other high-quality commercial securities.

Amortized cost and estimated fair market value of cash equivalents and marketable securities classified as available-for-sale at September 30, 2015, were as follows:

	Amortized Cost		Gross Unrealized					Estimated Fair Market Value
(In thousands)			Gains		Losses
Investments due in less than 3 months:
Commercial paper	$	18,019	$	—	$	—		$	18,019
Corporate securities	9,400		1		—			9,401
Total	27,419		1		—			27,420
Investments due in 4-12 months:
Corporate securities	64,306		72		(11		)	64,367
Total	64,306		72		(11		)	64,367
Investments due between 12 months and 5-years:
Corporate securities	5,004		5		—			5,009
Total	5,004		5		—			5,009
Total marketable securities	$	96,729	$	78	$	(11	)	$	96,796

Amortized cost and estimated fair market value of marketable securities classified as available-for-sale at December 31, 2014, were as follows:    

	Amortized Cost		Gross Unrealized					Estimated Fair Market Value
(In thousands)			Gains		Losses
Investments due in 4-12 months:
Corporate securities	$	30,233	$	36	$	—		$	30,269
Total	30,233		36		—			30,269
Investments due between 12 months and 5-years:
Corporate securities	84,259		92		(45		)	84,306
Total	84,259		92		(45		)	84,306
Total marketable securities	$	114,492	$	128	$	(45	)	$	114,575

As of September 30, 2015, and December 31, 2014, the Company evaluated the nature of the investments with a loss position, which were primarily high-quality corporate securities, and determined the unrealized losses were not other-than-temporary.

Revenue Recognition

Product revenues consist of sales to original equipment manufacturers (“OEMs”), merchant power supply manufacturers and distributors. Approximately 76% of the Company's net product sales were made to distributors in the ninemonths ended September 30, 2015, and 75%in the twelve months ended December 31, 2014. The Company applies the provisions of Accounting Standard Codification (“ASC”) 605-10 (“ASC 605-10”) and all related appropriate guidance. Revenue is recognized when all of the following criteria have been met: (1) persuasive evidence of an arrangement exists, (2) delivery has occurred, (3) the price is fixed or determinable, and (4) collectability is reasonably assured. Customer purchase orders are generally used to determine the existence of an arrangement. Delivery is considered to have occurred when title and risk of loss have transferred to the Company's customer. The Company evaluates whether the price is fixed or determinable based on the payment terms associated with the transaction and whether the sales price is subject to refund or adjustment. With respect to collectability, the Company performs credit checks for new customers and performs ongoing evaluations of its existing customers' financial condition and requires letters of credit whenever deemed necessary.

Sales to international OEM customers and merchant power supply manufacturers that are shipped from the Company's facility in California are pursuant to “delivered at frontier” (“DAF”) shipping terms. As such, title to the product passes to the customer when the shipment reaches the destination country and revenue is recognized upon the arrival of the product in that country. Sales to international OEMs and merchant power supply manufacturers for shipments from the Company's facility outside of the United States are pursuant to “EX Works” ("EXW") shipping terms, meaning that title to the product transfers to the customer upon shipment from the Company's foreign warehouse. Shipments to OEMs and merchant power supply manufacturers in the Americas are pursuant to “free on board” (“FOB”) point of origin shipping terms, meaning that title is passed to the customer upon shipment. Revenue is recognized upon title transfer for sales to OEMs and merchant power supply manufacturers, assuming all other criteria for revenue recognition are met.

Sales to most of the Company's distributors are made under terms allowing certain price adjustments and rights of return on the Company's products held by its distributors. As a result of these rights, the Company defers the recognition of revenue and the costs of revenues derived from sales to distributors until the Company's distributors report that they have sold the Company's products to their customers. The Company's recognition of such distributor revenue is based on point of sale reports received from the distributors, at which time the price is no longer subject to adjustment and is fixed, and the products are no longer subject to return to the Company except pursuant to warranty terms. The gross profit that is deferred as a result of this policy is reflected as “deferred income on sales to distributors” in the accompanying condensed consolidated balance sheets. The total deferred revenue as of September 30, 2015, and December 31, 2014, was approximately $28.4 million and $25.0 million, respectively. The total deferred cost as of September 30, 2015, and December 31, 2014, was approximately $11.9 million and $9.8 million, respectively.

Frequently, distributors need to sell at a price lower than the standard distribution price in order to win business. At or soon after the distributor invoices its customer, the distributor submits a “ship and debit” price adjustment claim to the Company to adjust the distributor's cost from the standard price to the pre-approved lower price. After verification by the Company, a credit memo is issued to the distributor for the ship and debit claim. The Company maintains a reserve for unprocessed claims and future ship and debit price adjustments. The reserve appears as a reduction to accounts receivable in the Company's accompanying consolidated balance sheets. To the extent future ship and debit claims significantly exceed amounts estimated, there could be a material impact on the deferred revenue and deferred margin ultimately recognized. To evaluate the adequacy of its reserves, the Company analyzes historical ship and debit payments and levels of inventory in the distributor channels.

Sales to certain of the Company's distributors are made under terms that do not include rights of return or price concessions after the product is shipped to the distributor. Accordingly, product revenue is recognized upon shipment and title transfer assuming all other revenue recognition criteria are met.

Common Stock Repurchases and Cash Dividend

In October 2012, the Company's board of directors authorized the use of $50.0 million for the repurchase of the Company's common stock. In the year ended December 31, 2014 and in July 2015, the Company's board of directors authorized the use of an additional $75.0 million and $30.0 million, respectively, for repurchase of the Company's common stock, with repurchases to be executed according to pre-defined price/volume guidelines. In the year ended December 31, 2014, the Company purchased 1.6 million shares for $80.8 million, and in the nine months ended September 30, 2015, the Company purchased approximately 1.3 million shares for $53.7 million. As of September 30, 2015, the Company had used up the amount authorized for repurchase.

In October 2015, the Company's board of directors authorized the use of an additional $30.0 million for the repurchase of the Company's common stock. Authorization of future repurchase programs is at the discretion of the board of directors and will depend on the Company's financial condition, results of operations, capital requirements, business conditions and other factors.

In October 2013, the Company's board of directors declared four quarterly cash dividends in the amount of $0.10 per share to be paid to stockholders of record at the end of each quarter in 2014. Dividend payouts totaling approximately $3.0 million each were paid on March 31, 2014 and June 30, 2014. In April 2014, the Company's board of directors increased the quarterly dividends for the third and fourth quarters of 2014 to $0.12 per share. Dividend payouts totaling approximately $3.6 million and $3.5 million were paid on September 30, 2014 and December 31, 2014, respectively.

In January 2015, the Company's board of directors extended the $0.12 quarterly dividend through each quarter in 2015. Dividend payouts totaling $3.5 million each were paid on March 31, June 30, and September 30, 2015. The declaration of any future cash dividend is at the discretion of the board of directors and will depend on the Company's financial condition, results of operations, capital requirements, business conditions and other factors, as well as a determination that cash dividends are in the best interests of the Company's stockholders.

Use of Estimates

The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosures of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. On an ongoing basis, the Company evaluates its estimates, including those related to revenue recognition, income tax, stock-based compensation and inventories. These estimates are based on historical facts and various other assumptions that the Company believes to be reasonable at the time the estimates are made.

Components of the Company's Condensed Consolidated Balance Sheets    

Accounts Receivable:

(In thousands)	September 30, 2015			December 31, 2014
Accounts receivable trade	$	46,816		$	38,344
Accrued ship and debit and rebate claims	(35,436		)	(27,967		)
Allowance for doubtful accounts	(319		)	(191		)
Total	$	11,061		$	10,186

Prepaid Expenses and Other Current Assets:

(In thousands)	September 30, 2015		December 31, 2014
Prepaid legal fees	$	23	$	1,506
Loan to Cambridge Semiconductor (Note 10)	—		6,600
Prepaid income tax	1,386		3,208
Prepaid maintenance agreements	866		1,023
Interest receivable	371		664
VAT receivable	525		987
Supplier prepayment	366		800
Other	2,243		1,591
Total	$	5,780	$	16,379

Changes in accumulated other comprehensive income (loss) for the three months ended September 30, 2015 and 2014:

	Unrealized Gains and Losses on Marketable Securities					Defined Benefit Pension Items										Foreign Currency Items						Total
	Three Months Ended					Three Months Ended										Three Months Ended						Three Months Ended
	September 30,					September 30,										September 30,						September 30,
(In thousands)	2015		2014			2015					2014					2015			2014			2015			2014
Beginning balance	$	46	$	449		$	(1,212	)			$	(750	)			$	(1	)	$	111		$	(1,167	)	$	(190	)
Other comprehensive income (loss) before reclassifications	20		(246		)	—					—					40			(53		)	60			(299		)
Amounts reclassified from accumulated other comprehensive income	—		—			64			(1	)	15			(1	)	—			—			64			15
Net-current period other comprehensive income (loss)	20		(246		)	64					15					40			(53		)	124			(284		)
Ending balance	$	66	$	203		$	(1,148	)			$	(735	)			$	39		$	58		$	(1,043	)	$	(474	)

_______________

(1) This component of accumulated other comprehensive income is included in the computation of net periodic pension cost for the three months ended September 30, 2015 and 2014.

Changes in accumulated other comprehensive income (loss) for the nine months ended September 30, 2015 and 2014:

	Unrealized Gains and Losses on Marketable Securities						Defined Benefit Pension Items										Foreign Currency Items					Total
	Nine Months Ended						Nine Months Ended										Nine Months Ended					Nine Months Ended
	September 30,						September 30,										September 30,					September 30,
(In thousands)	2015			2014			2015					2014					2015		2014			2015			2014
Beginning balance	$	83		$	210		$	(1,240	)			$	(780	)			$	21	$	100		$	(1,136	)	$	(470	)
Other comprehensive income (loss) before reclassifications	(17		)	(7		)	—					—					18		(42		)	1			(49		)
Amounts reclassified from accumulated other comprehensive income	—			—			92			(1	)	45			(1	)	—		—			92			45
Net-current period other comprehensive income (loss)	(17		)	(7		)	92					45					18		(42		)	93			(4		)
Ending balance	$	66		$	203		$	(1,148	)			$	(735	)			$	39	$	58		$	(1,043	)	$	(474	)

_______________

(1) This component of accumulated other comprehensive income is included in the computation of net periodic pension cost for the nine months ended September 30, 2015 and 2014.

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GOODWILL AND INTANGIBLE ASSETS (Finite Lived Intangible Assets) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Aug. 31, 2015	Jan. 02, 2015	Dec. 31, 2014
Intangible Assets, Net[Abstract]
Finite-Lived Intangible Assets, Gross	$ 68,460		$ 68,460				$ 58,780
Amortization of intangibles	1,700	$ 1,300	5,247	$ 4,723
Finite-Lived Intangible Assets, Accumulated Amortization	(28,503)		(28,503)				(23,256)
Finite-Lived Intangible Assets, Net	39,957		39,957				35,524
Internet Domain Names [Member]
Intangible Assets, Net[Abstract]
Indefinite-Lived Intangible Assets	1,261		1,261				1,261
In Process Research and Development [Member]
Intangible Assets, Net[Abstract]
Finite-Lived Intangible Assets, Gross	4,690		4,690				4,690
Finite-Lived Intangible Assets, Accumulated Amortization	0		0				0
Finite-Lived Intangible Assets, Net	4,690		4,690				4,690
Technology licenses [Member]
Intangible Assets, Net[Abstract]
Finite-Lived Intangible Assets, Gross	3,000		3,000				3,000
Finite-Lived Intangible Assets, Accumulated Amortization	(2,850)		(2,850)				(2,625)
Finite-Lived Intangible Assets, Net	150		150				375
Patents [Member]
Intangible Assets, Net[Abstract]
Finite-Lived Intangible Assets, Gross	1,949		1,949				1,949
Finite-Lived Intangible Assets, Accumulated Amortization	(1,949)		(1,949)				(1,949)
Finite-Lived Intangible Assets, Net	0		0				0
Developed technology [Member]
Intangible Assets, Net[Abstract]
Finite-Lived Intangible Assets, Gross	33,270		33,270				26,670
Finite-Lived Intangible Assets, Accumulated Amortization	(10,708)		(10,708)				(7,828)
Finite-Lived Intangible Assets, Net	22,562		22,562				18,842
Customer relationships [Member]
Intangible Assets, Net[Abstract]
Finite-Lived Intangible Assets, Gross	20,030		20,030				17,610
Finite-Lived Intangible Assets, Accumulated Amortization	(9,366)		(9,366)				(7,254)
Finite-Lived Intangible Assets, Net	10,664		10,664				10,356
Trade Names [Member]
Intangible Assets, Net[Abstract]
Finite-Lived Intangible Assets, Gross	3,600		3,600				3,600
Finite-Lived Intangible Assets, Accumulated Amortization	(3,600)		(3,600)				(3,600)
Finite-Lived Intangible Assets, Net	0		0				0
Leases, Acquired-in-Place [Member]
Intangible Assets, Net[Abstract]
Finite-Lived Intangible Assets, Gross	660		660				0
Finite-Lived Intangible Assets, Accumulated Amortization	(30)		(30)				0
Finite-Lived Intangible Assets, Net	$ 630		$ 630				$ 0
Minimum [Member]
Intangible Assets, Net[Abstract]
Estimated Useful Life (in years)			2 years
Maximum [Member]
Intangible Assets, Net[Abstract]
Estimated Useful Life (in years)			12 years
Cambridge Semiconductor Limited [Member]
Intangible Assets, Net[Abstract]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles						$ 9,020
Cambridge Semiconductor Limited [Member] | Developed technology [Member]
Intangible Assets, Net[Abstract]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles						6,600
Cambridge Semiconductor Limited [Member] | Developed technology [Member] | Minimum [Member]
Intangible Assets, Net[Abstract]
Estimated Useful Life (in years)			3 years
Cambridge Semiconductor Limited [Member] | Developed technology [Member] | Maximum [Member]
Intangible Assets, Net[Abstract]
Estimated Useful Life (in years)			7 years
Cambridge Semiconductor Limited [Member] | Customer relationships [Member]
Intangible Assets, Net[Abstract]
Estimated Useful Life (in years)			5 years
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles						$ 2,420
Building [Member]
Intangible Assets, Net[Abstract]
Estimated Useful Life (in years)			2 years
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles					$ 700
Building [Member] | Leases, Acquired-in-Place [Member]
Intangible Assets, Net[Abstract]
Estimated Useful Life (in years)			2 years
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles					$ 700

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SIGNIFICANT CUSTOMERS AND INTERNATIONAL SALES (Tables)

9 Months Ended

Sep. 30, 2015

Concentration Risk [Line Items]

International sales

As a percentage of total net revenues, international sales, which consist of sales to distributors and direct customers outside of the United States of America, comprise the following:     

	Three Months  Ended				Nine Months Ended
	September 30,				September 30,
	2015		2014		2015		2014
Hong Kong/China	49	%	47	%	49	%	46	%
Taiwan	15	%	16	%	14	%	16	%
Korea	10	%	11	%	10	%	11	%
Western Europe (excluding Germany)	11	%	11	%	11	%	11	%
Japan	4	%	5	%	5	%	5	%
Germany	3	%	2	%	3	%	2	%
Other	3	%	4	%	3	%	4	%
Total foreign revenue	95	%	96	%	95	%	95	%

Revenue mix by product family

The table below provides the percentage of net sales activity by end market for the three and nine months ended September 30, 2015 and 2014:

	Three Months Ended				Nine Months Ended
	September 30,				September 30,
End Market	2015		2014		2015		2014
Communications	26	%	18	%	23	%	17	%
Computer	7	%	11	%	7	%	11	%
Consumer	36	%	36	%	37	%	37	%
Industrial	31	%	35	%	33	%	35	%

Sales Revenue, Goods, Net [Member]

Concentration Risk [Line Items]

Schedules of Concentration of Risk, by Risk Factor

The following table discloses these customers' percentage of revenues for the respective periods:    

	Three Months Ended				Nine Months Ended
	September 30,				September 30,
Customer	2015		2014		2015		2014
Avnet	20	%	19	%	21	%	20	%
Powertech Distribution Ltd.	11	%	*		*		*

Accounts Receivable [Member]

Concentration Risk [Line Items]

Schedules of Concentration of Risk, by Risk Factor

The following customers represented 10% or more of accounts receivable:

Customer	September 30, 2015		December 31, 2014
Avnet	23	%	22	%
ATM Electronic Corporation	12	%	*
Burnon International LTD.	*		11	%

_______________                        

* Total customer accounts receivable was less than 10%.

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GOODWILL AND INTANGIBLE ASSETS (Tables)

9 Months Ended

Sep. 30, 2015

Goodwill and Intangible Assets Disclosure [Abstract]

Summary of Changes in the Carrying Amount of Goodwill

Changes in the carrying amount of goodwill during the nine months ended September 30, 2015, are as follows:

(In thousands)	Goodwill
Balance at December 31, 2014	$	80,599
Goodwill acquired during the period	11,250
Ending balance at September 30, 2015	$	91,849

Schedule of intangible assets

The Company does not believe there is any significant residual value associated with its finite-lived intangible assets:

	September 30, 2015							December 31, 2014
(In thousands)	Gross		Accumulated Amortization			Net		Gross		Accumulated Amortization			Net
Domain name	$	1,261	$	—		$	1,261	$	1,261	$	—		$	1,261
In-process research and development	4,690		—			4,690		4,690		—			4,690
Technology licenses	3,000		(2,850		)	150		3,000		(2,625		)	375
Patent rights	1,949		(1,949		)	—		1,949		(1,949		)	—
Developed technology	33,270		(10,708		)	22,562		26,670		(7,828		)	18,842
Customer relationships	20,030		(9,366		)	10,664		17,610		(7,254		)	10,356
Trade name	3,600		(3,600		)	—		3,600		(3,600		)	—
In-place leases	660		(30		)	630		—		—			—
Total intangible assets	$	68,460	$	(28,503	)	$	39,957	$	58,780	$	(23,256	)	$	35,524

Schedule of expected amortization expense

The estimated future amortization expense related to finite-lived intangible assets at September 30, 2015, is as follows:

Fiscal Year	Estimated Amortization (in thousands)
2015 (remaining 3 months)	$	1,792
2016	6,663
2017	6,084
2018	5,152
2019	4,753
Thereafter	9,562
Total (1)	$	34,006

_______________

(1) The total above excludes $4.7 million of in-process research and development that will be amortized, upon completion of development, over the estimated useful life of the technology.

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GOODWILL AND INTANGIBLE ASSETS Goodwill (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2015 USD ($)
Goodwill and Intangible Assets Disclosure [Abstract]
Balance at December 31, 2014	$ 80,599
Goodwill acquired during the period	11,250
Ending balance at September 30, 2015	$ 91,849

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EARNINGS PER SHARE (Tables)

9 Months Ended

Sep. 30, 2015

Earnings Per Share [Abstract]

Earnings per share calculation

A summary of the earnings per share calculation is as follows:        

	Three Months Ended				Nine Months Ended
	September 30,				September 30,
(In thousands, except per share amounts)	2015		2014		2015		2014
Basic earnings per share:
Net income	$	11,513	$	16,111	$	26,446	$	45,190
Weighted-average common shares	28,855		30,013		29,175		30,186
Basic earnings per share	$	0.40	$	0.54	$	0.91	$	1.50
Diluted earnings per share: (1)
Net income	$	11,513	$	16,111	$	26,446	$	45,190
Weighted-average common shares	28,855		30,013		29,175		30,186
Effect of dilutive awards:
Employee stock plans	443		744		681		867
Diluted weighted-average common shares	29,298		30,757		29,856		31,053
Diluted earnings per share	$	0.39	$	0.52	$	0.89	$	1.46

_______________ 

(1) The Company includes the shares underlying performance-based awards in the calculation of diluted earnings per share if the performance conditions have been satisfied as of the end of the reporting period and excludes such shares when the necessary conditions have not been met. The Company has excluded the shares underlying the 2015 and 2014 awards in the 2015 and 2014 calculations, respectively, as those shares were not contingently issuable as of the end of the period. 

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ACQUISITIONS (Tables)

9 Months Ended

Sep. 30, 2015

Business Combinations [Abstract]

Schedule of Recognized Identified Assets Acquired and Liabilities Assumed

The following table summarizes the purchase price and preliminary estimated fair values of the assets acquired and the liabilities assumed as of January 2, 2015. The allocation of the purchase price is preliminary as certain pre-acquisition liabilities and corporate taxes are still being finalized and may be adjusted should further information regarding events or circumstances existing as of the acquisition date become available.

(In thousands)		Total Amount
Assets Acquired
	Cash	$	1,134
	Accounts receivable	1,891
	Inventories	1,409
	Prepaid expenses and other current assets	408
	Tax receivable	1,093
	Intangible assets:
	Developed technology	6,600
	Customer relationships	2,420
	Goodwill	11,250
	Total assets acquired	26,205
Liabilities Assumed
	Current liabilities	1,832
	Taxes payable	1,090
	Total liabilities assumed	2,922
	Total purchase price	$	23,283

Schedule of Purchased Intangible

The following table represents details of the purchased intangible assets:

	Fair Value Amount (in thousands)		Estimated Useful Life (in years)
Developed technology	$	6,600	3	-	7
Customer relationships	2,420		5
Total acquired CamSemi intangibles	$	9,020

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BASIS OF PRESENTATION

9 Months Ended

Sep. 30, 2015

Organization, Consolidation and Presentation of Financial Statements [Abstract]

BASIS OF PRESENTATION

BASIS OF PRESENTATION:

The condensed consolidated financial statements include the accounts of Power Integrations, Inc., a Delaware corporation (the “Company”), and its wholly owned subsidiaries. Significant intercompany accounts and transactions have been eliminated in consolidation.

While the financial information furnished is unaudited, the condensed consolidated financial statements included in this report reflect all adjustments (consisting only of normal recurring adjustments) that the Company considers necessary for the fair presentation of the results of operations for the interim periods covered and the financial condition of the Company at the date of the interim balance sheet in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”). The results for interim periods are not necessarily indicative of the results for the entire year. The condensed consolidated financial statements should be read in conjunction with the Power Integrations, Inc. consolidated financial statements and the notes thereto for the year ended December 31, 2014, included in its Form 10-K filed on February 10, 2015, with the Securities and Exchange Commission.

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SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Narrative) (Details) $ / shares in Units, shares in Millions								1 Months Ended			9 Months Ended		12 Months Ended
	Sep. 30, 2015 USD ($) $ / shares	Jun. 30, 2015 USD ($) $ / shares	Mar. 31, 2015 USD ($) $ / shares	Dec. 31, 2014 USD ($) $ / shares	Sep. 30, 2014 USD ($) $ / shares	Jun. 30, 2014 USD ($) $ / shares	Mar. 31, 2014 USD ($) $ / shares	Jan. 31, 2015 $ / shares	Apr. 30, 2014 $ / shares	Oct. 31, 2013 Quarter $ / shares	Sep. 30, 2015 USD ($) shares	Sep. 30, 2014 USD ($)	Dec. 31, 2014 USD ($) shares	Oct. 28, 2015 USD ($)	Jul. 28, 2015 USD ($)	Oct. 31, 2012 USD ($)
Class of Stock [Line Items]
Net Product Sales to Distributors, Percentage											76.00%		75.00%
Deferred Revenue, Gross	$ 28,400,000			$ 25,000,000							$ 28,400,000		$ 25,000,000
Other Deferred Costs, Net	11,900,000			9,800,000							$ 11,900,000		$ 9,800,000
Stock Repurchased and Retired During Period, Shares | shares											1.3		1.6
Stock Repurchased and Retired During Period, Value											$ 53,700,000		$ 80,800,000
Stock Repurchase Program, Remaining Authorized Repurchase Amount	0										0
Common Stock, Dividends, Per Share, Declared (in dollars per share) | $ / shares								$ 0.12	$ 0.12	$ 0.10
Payments of Dividends	$ 3,500,000	$ 3,500,000	$ 3,500,000	$ 3,500,000	$ 3,600,000	$ 3,000,000	$ 3,000,000				$ 10,501,000	$ 9,654,000
Common Stock, Dividends, Per Share, Cash Paid (in dollars per share) | $ / shares	$ 0.12	$ 0.12	$ 0.12	$ 0.12	$ 0.12	$ 0.10	$ 0.10
Common Stock, Dividends, Per Share, Declared, Fiscal 2015, Period Four (in dollars per share) | $ / shares								$ 0.12
Dividends Declared, Number Of Quarters | Quarter										4
Common Stock [Member]
Class of Stock [Line Items]
Stock Repurchase Program, Authorized Amount				$ 75,000,000									$ 75,000,000		$ 30,000,000	$ 50,000,000
Common Stock [Member] | Subsequent Event [Member]
Class of Stock [Line Items]
Stock Repurchase Program, Authorized Amount														$ 30,000,000

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STOCK PLANS AND SHARE-BASED COMPENSATION (Performance-based Awards and Restricted Stock Units) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Performance Based Awards (PSUs) [Member]
Shares
Outstanding at beginning of period (in shares)			0
Granted shares (in shares)			88,000
Vested (in shares)			0
Change in units due to performance achievement for PSUs vested in the year (in shares)			0
Forfeited or expired (in shares)			(1,000)
Outstanding at period end (in shares)	87,000		87,000
Outstanding and expected to vest at period end (in shares)	12,000		12,000
Weighted- Average Grant Date Fair Value Per Share
Outstanding at beginning of period (in dollars per share)			$ 0.00
Granted (in dollars per share)	$ 37.81	$ 0	52.39	$ 53.93
Vested (in dollars per share)			0.00
Change in units due to performance achievement for PSUs vested in the year (in dollars per share)			0.00
Forfeited or expired (in dollars per share)			50.79
Outstanding at period end (in dollars per share)	$ 52.41		$ 52.41
Weighted-Average Remaining Contractual Term (in years)
Outstanding and expected to vest, weighted-average remaining contractual term, at period end			3 months
Outstanding and expected to vest, weighted-average remaining contractual term, at period end			3 months
Aggregate Intrinsic Value (in thousands)
Outstanding, aggregate intrinsic value, at period end	$ 3,684		$ 3,684
Outstanding and expected to vest, aggregate intrinsic value, at period end	$ 516		$ 516
Long-Term Performance-based Awards (PRSUs) [Member]
Shares
Outstanding at beginning of period (in shares)			61,000
Granted shares (in shares)	0	0	72,000
Vested (in shares)			0
Forfeited or expired (in shares)			(4,000)
Outstanding at period end (in shares)	129,000		129,000
Outstanding and expected to vest at period end (in shares)	17,000		17,000
Weighted- Average Grant Date Fair Value Per Share
Outstanding at beginning of period (in dollars per share)			$ 55.51
Granted (in dollars per share)			52.47	56.15
Vested (in dollars per share)			0.00
Forfeited or expired (in dollars per share)			57.76
Outstanding at period end (in dollars per share)	$ 53.75		$ 53.75
Weighted-Average Remaining Contractual Term (in years)
Outstanding and expected to vest, weighted-average remaining contractual term, at period end			1 year 9 months 22 days
Outstanding and expected to vest, weighted-average remaining contractual term, at period end			1 year 9 months 15 days
Aggregate Intrinsic Value (in thousands)
Outstanding, aggregate intrinsic value, at period end	$ 5,427		$ 5,427
Outstanding and expected to vest, aggregate intrinsic value, at period end	$ 724		$ 724
Restricted Stock Units (RSUs) [Member]
Shares
Outstanding at beginning of period (in shares)			692,000
Granted shares (in shares)			302,000
Vested (in shares)			(257,000)
Forfeited or expired (in shares)			(48,000)
Outstanding at period end (in shares)	689,000		689,000
Outstanding and expected to vest at period end (in shares)	636,000		636,000
Weighted- Average Grant Date Fair Value Per Share
Outstanding at beginning of period (in dollars per share)			$ 43.86
Granted (in dollars per share)	$ 42.65	$ 58.03	49.90	$ 51.30
Vested (in dollars per share)			42.49
Forfeited or expired (in dollars per share)			45.55
Outstanding at period end (in dollars per share)	$ 46.90		$ 46.90
Weighted-Average Remaining Contractual Term (in years)
Outstanding and expected to vest, weighted-average remaining contractual term, at period end			1 year 5 months 15 days
Outstanding and expected to vest, weighted-average remaining contractual term, at period end			1 year 4 months 25 days
Aggregate Intrinsic Value (in thousands)
Outstanding, aggregate intrinsic value, at period end	$ 29,073		$ 29,073
Outstanding and expected to vest, aggregate intrinsic value, at period end	$ 26,804		$ 26,804

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LEGAL PROCEEDINGS AND CONTINGENCIES (Details) $ in Millions		1 Months Ended											3 Months Ended		9 Months Ended
	May. 01, 2012 patent	Feb. 28, 2014 USD ($)	Feb. 28, 2011 USD ($)	May. 31, 2010 patent	Feb. 28, 2010 USD ($) patent	Dec. 31, 2009 patent	Nov. 30, 2009 patent	Dec. 31, 2008 USD ($)	Nov. 30, 2008 patent	May. 31, 2008 patent	Oct. 31, 2006 USD ($)	Oct. 31, 2004 patent	Sep. 30, 2015	Dec. 31, 2012 patent	Sep. 30, 2015 USD ($)
Gain and Loss Contingencies [Line Items]
Loss Contingency, Damages Awarded, Value | $															$ 2.4
Patent Infringment Claim Five [Member] | Counterclaims [Member]
Gain and Loss Contingencies [Line Items]
Number of patents in filed infringement claims	5
Pending Litigation [Member] | Patent Infringement Claim One [Member]
Gain and Loss Contingencies [Line Items]
Period for petition for further stay of permanent injunction								90 days
Pending Litigation [Member] | Patent Infringement Claim Two [Member]
Gain and Loss Contingencies [Line Items]
Number of patents in filed infringement claims									3
Number of patents withdrawn from infringement claims						1
Number of patents remaining in infringement claims						2
Potential impact on revenue by patent litigation (as a percentage)													0.30%
Pending Litigation [Member] | Patent Infringement Claim Three [Member]
Gain and Loss Contingencies [Line Items]
Number of patents in filed infringement claims				2
Number of patents withdrawn from infringement claims				1
Number of Patents Added to Infringement Claims														1
Pending Litigation [Member] | Patent Infringement Claim Four [Member]
Gain and Loss Contingencies [Line Items]
Number of patents in filed infringement claims					4
Damages sought after the Company | $					$ 19.0
Pending Litigation [Member] | Patent Infringment Claim Five [Member]
Gain and Loss Contingencies [Line Items]
Number of patents in filed infringement claims	4
Number of patents withdrawn from infringement claims	1
Positive Outcome of Litigation [Member] | Patent Infringement Claim One [Member]
Gain and Loss Contingencies [Line Items]
Number of patents in filed infringement claims												4
Damages awarded to the Company | $			$ 12.9					$ 6.1			$ 34.0
Positive Outcome of Litigation [Member] | Patent Infringement Claim Two [Member]
Gain and Loss Contingencies [Line Items]
Number of patents in filed infringement claims										3
Positive Outcome of Litigation [Member] | Patent Infringement Claim Three [Member]
Gain and Loss Contingencies [Line Items]
Number of patents in filed infringement claims							2
Damages awarded to the Company | $		$ 105.0
Number of patents in infringement case deemed unenforceable by Fairchild							1

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CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
CURRENT ASSETS:
Cash and cash equivalents	$ 59,735	$ 60,708
Short-term marketable securities	91,222	114,575
Accounts receivable, net of allowances of $319 and $191 in 2015 and 2014, respectively (Note 2)	11,061	10,186
Inventories	55,439	64,025
Deferred tax assets	75	39
Prepaid expenses and other current assets	5,780	16,379
Total current assets	223,312	265,912
PROPERTY AND EQUIPMENT, net	102,223	95,823
INTANGIBLE ASSETS, net	39,957	35,524
GOODWILL	91,849	80,599
DEFERRED TAX ASSETS	10,647	11,562
OTHER ASSETS	5,502	4,243
Total assets	473,490	493,663
CURRENT LIABILITIES:
Accounts payable	23,370	21,980
Accrued payroll and related expenses	8,203	9,071
Taxes payable	2,022	2,963
Deferred tax liabilities	1,985	2,193
Deferred income on sales to distributors	16,464	15,223
Other accrued liabilities	3,182	3,730
Total current liabilities	55,226	55,160
LONG-TERM INCOME TAXES PAYABLE	746	743
DEFERRED TAX LIABILITIES	3,752	4,272
OTHER LIABILITIES	2,569	2,812
Total liabilities	$ 62,293	$ 62,987
COMMITMENTS AND CONTINGENCIES (Notes 9, 11, 12 and 15)
STOCKHOLDERS’ EQUITY:
Common stock	$ 28	$ 29
Additional paid-in capital	136,422	171,938
Accumulated other comprehensive loss	(1,043)	(1,136)
Retained earnings	275,790	259,845
Total stockholders’ equity	411,197	430,676
Total liabilities and stockholders’ equity	$ 473,490	$ 493,663

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GOODWILL AND INTANGIBLE ASSETS (Future Amortization Expense) (Details) - USD ($) $ in Thousands		Sep. 30, 2015	Dec. 31, 2014
Finite-Lived Intangible Assets, Future Amortization Expense [Abstract]
2015 (remaining 3 months)		$ 1,792
2016		6,663
2017		6,084
2018		5,152
2019		4,753
Thereafter		9,562
Total	[1]	34,006
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross		68,460	$ 58,780
In Process Research and Development [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross		$ 4,690	$ 4,690

[1] The total above excludes $4.7 million of in-process research and development that will be amortized, upon completion of development, over the estimated useful life of the technology.

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CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Unaudited) (PARENTHETICAL) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Statement of Comprehensive Income [Abstract]
Foreign currency translation adjustments, tax	$ 0	$ 0	$ 0	$ 0
Unrealized gain (loss) on marketable securities, tax	0	0	0	0
Amortization of defined benefit pension items, tax	$ 18	$ 4	$ 26	$ 12

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SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Changes in Accumulated Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Thousands	3 Months Ended				9 Months Ended
	Sep. 30, 2015		Sep. 30, 2014		Sep. 30, 2015		Sep. 30, 2014
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	$ (1,167)		$ (190)		$ (1,136)		$ 470
Other comprehensive income (loss) before reclassifications	60		(299)		1		(49)
Amounts reclassified from accumulated other comprehensive income	(64)		(15)		(92)		(45)
Net-current period other comprehensive income (loss)	124		(284)		93		(4)
Ending balance	(1,043)		(474)		(1,043)		(474)
Accumulated Net Unrealized Investment Gain (Loss) [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	46		449		83		210
Other comprehensive income (loss) before reclassifications	20		(246)		(17)		(7)
Amounts reclassified from accumulated other comprehensive income	0		0		0		0
Net-current period other comprehensive income (loss)	20		(246)		(17)		(7)
Ending balance	66		203		66		203
Accumulated Defined Benefit Plans Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	(1,212)		(750)		(1,240)		(780)
Other comprehensive income (loss) before reclassifications	0		0		0		0
Amounts reclassified from accumulated other comprehensive income	(64)	[1]	(15)	[1]	(92)	[2]	(45)	[2]
Net-current period other comprehensive income (loss)	64		15		92		45
Ending balance	(1,148)		(735)		(1,148)		(735)
Accumulated Translation Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	(1)		111		21		100
Other comprehensive income (loss) before reclassifications	40		(53)		18		(42)
Amounts reclassified from accumulated other comprehensive income	0		0		0		0
Net-current period other comprehensive income (loss)	40		(53)		18		(42)
Ending balance	$ 39		$ 58		$ 39		$ 58

[1] This component of accumulated other comprehensive income is included in the computation of net periodic pension cost for the three months ended September 30, 2015 and 2014.

[2] This component of accumulated other comprehensive income is included in the computation of net periodic pension cost for the nine months ended September 30, 2015 and 2014.

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INDEMNIFICATIONS

9 Months Ended

Sep. 30, 2015

Commitments and Contingencies Disclosure [Abstract]

INDEMNIFICATIONS

INDEMNIFICATIONS:

The Company sells products to its distributors under contracts, collectively referred to as Distributor Sales Agreements (“DSA”). Each DSA contains the relevant terms of the contractual arrangement with the distributor, and generally includes certain provisions for indemnifying the distributor against losses, expenses, and liabilities from damages that may be awarded against the distributor in the event the Company's products are found to infringe upon a patent, copyright, trademark, or other proprietary right of a third party (“Customer Indemnification”). The DSA generally limits the scope of and remedies for the Customer Indemnification obligations in a variety of industry-standard respects, including, but not limited to, limitations based on time and geography, and a right to replace an infringing product. The Company also, from time to time, has granted a specific indemnification right to individual customers.

The Company believes its internal development processes and other policies and practices limit its exposure related to such indemnifications. In addition, the Company requires its employees to sign a proprietary information and inventions agreement, which assigns the rights to its employees' development work to the Company. To date, the Company has not had to reimburse any of its distributors or customers for any losses related to these indemnifications and no material claims were outstanding as of September 30, 2015. For several reasons, including the lack of prior indemnification claims and the lack of a monetary liability limit for certain infringement cases, the Company cannot determine the maximum amount of potential future payments, if any, related to such indemnifications.

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STOCK PLANS AND SHARE-BASED COMPENSATION (Narrative) (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2015 USD ($) $ / shares shares	Sep. 30, 2014 USD ($) $ / shares shares	Sep. 30, 2015 USD ($) Plan purchaseperiods $ / shares shares	Sep. 30, 2014 USD ($) $ / shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of stock-based compensation plans | Plan			2
Allocated stock-based compensation expense	$ 3,361,000	$ 2,580,000	$ 11,502,000	$ 10,670,000
Equity Incentive Plan 2007 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares available for future issuance (in shares) | shares	6,377,504		6,377,504
Employee Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares available for future issuance (in shares) | shares	191,735		191,735
Maximum percentage of employee's compensation eligible for payroll deductions	15.00%		15.00%
Purchase price of the purchase plan as percentage of the lower of the fair market value on the first day of each offering period or on the purchase date			85.00%
Number of purchase period in each offering period | purchaseperiods			1
Shares reserved for issuance (in shares) | shares	3,000,000		3,000,000
Employee shares purchased under employee stock purchase plan (in shares) | shares	2,808,265		2,808,265
Allocated stock-based compensation expense	$ 300,000	400,000	$ 900,000	900,000
Duration of each purchase period in each offering period			6 months
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period			4 years
Allocated stock-based compensation expense	$ 3,200,000	$ 2,800,000	$ 9,500,000	$ 8,400,000
Reduction in number of shares available for issuance under the 2007 Plan per award granted (in shares) | shares			2
Granted shares (in shares) | shares			302,000
Weighted-average grant date fair value per granted share (in dollars per share) | $ / shares	$ 42.65	$ 58.03	$ 49.90	$ 51.30
Grant date fair value of awards released	$ 400,000	$ 500,000	$ 10,900,000	$ 10,000,000
Performance Based Awards (PSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Reduction in number of shares available for issuance under the 2007 Plan per award granted (in shares) | shares			2
Granted shares (in shares) | shares			88,000
Weighted-average grant date fair value per granted share (in dollars per share) | $ / shares	$ 37.81	$ 0	$ 52.39	$ 53.93
Grant date fair value of awards released	$ 0	$ 0	$ 0	$ 3,200,000
Number of performance-based awards shares released as percentage of target number, minimum			0.00%
Number of performance-based awards shares released as percentage of target number, maximum			200.00%
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period			48 months
Awards expiration period, maximum (in years)			10 years
Allocated stock-based compensation expense	100,000	200,000	$ 500,000	1,000,000
Intrinsic Value of Options Exercised	300,000	1,800,000	2,400,000	8,700,000
Performance Based Awards and Long Term Performance based Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Allocated stock-based compensation expense	$ (200,000)	$ (800,000)	$ 600,000	$ 400,000
Long-Term Performance-based Awards (PRSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Reduction in number of shares available for issuance under the 2007 Plan per award granted (in shares) | shares			2
Granted shares (in shares) | shares	0	0	72,000
Weighted-average grant date fair value per granted share (in dollars per share) | $ / shares			$ 52.47	$ 56.15
Service period to receive shares			3 years
Number of performance-based awards shares released as percentage of target number, minimum			0.00%
Number of performance-based awards shares released as percentage of target number, maximum			200.00%
Equity Incentive Plan 2007 [Member] | Incentive Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise price of stock options as percentage of fair market value on date of grant, minimum			100.00%
Equity Incentive Plan 2007 [Member] | Nonstatutory Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise price of stock options as percentage of fair market value on date of grant, minimum			100.00%
Directors Equity Compensation Program [Member] | Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Factor used to determine the number of options/units to be granted			$ 100,000
Directors Equity Compensation Program [Member] | Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Factor used to determine the number of options/units to be granted			100,000
Directors Equity Compensation Program [Member] | Stock Options and Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Factor used to determine the number of options/units to be granted			$ 100,000

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SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Tables)

9 Months Ended

Sep. 30, 2015

Accounting Policies [Abstract]

Available-for-sale Securities

Amortized cost and estimated fair market value of cash equivalents and marketable securities classified as available-for-sale at September 30, 2015, were as follows:

	Amortized Cost		Gross Unrealized					Estimated Fair Market Value
(In thousands)			Gains		Losses
Investments due in less than 3 months:
Commercial paper	$	18,019	$	—	$	—		$	18,019
Corporate securities	9,400		1		—			9,401
Total	27,419		1		—			27,420
Investments due in 4-12 months:
Corporate securities	64,306		72		(11		)	64,367
Total	64,306		72		(11		)	64,367
Investments due between 12 months and 5-years:
Corporate securities	5,004		5		—			5,009
Total	5,004		5		—			5,009
Total marketable securities	$	96,729	$	78	$	(11	)	$	96,796

Amortized cost and estimated fair market value of marketable securities classified as available-for-sale at December 31, 2014, were as follows:    

	Amortized Cost		Gross Unrealized					Estimated Fair Market Value
(In thousands)			Gains		Losses
Investments due in 4-12 months:
Corporate securities	$	30,233	$	36	$	—		$	30,269
Total	30,233		36		—			30,269
Investments due between 12 months and 5-years:
Corporate securities	84,259		92		(45		)	84,306
Total	84,259		92		(45		)	84,306
Total marketable securities	$	114,492	$	128	$	(45	)	$	114,575

Schedule of Accounts Receivable

Accounts Receivable:

(In thousands)	September 30, 2015			December 31, 2014
Accounts receivable trade	$	46,816		$	38,344
Accrued ship and debit and rebate claims	(35,436		)	(27,967		)
Allowance for doubtful accounts	(319		)	(191		)
Total	$	11,061		$	10,186

Schedule of Prepaid Expenses and Other Current Assets

Prepaid Expenses and Other Current Assets:

(In thousands)	September 30, 2015		December 31, 2014
Prepaid legal fees	$	23	$	1,506
Loan to Cambridge Semiconductor (Note 10)	—		6,600
Prepaid income tax	1,386		3,208
Prepaid maintenance agreements	866		1,023
Interest receivable	371		664
VAT receivable	525		987
Supplier prepayment	366		800
Other	2,243		1,591
Total	$	5,780	$	16,379

Summary of Changes in Accumulated Other Comprehensive Income (Loss)

Changes in accumulated other comprehensive income (loss) for the three months ended September 30, 2015 and 2014:

	Unrealized Gains and Losses on Marketable Securities					Defined Benefit Pension Items										Foreign Currency Items						Total
	Three Months Ended					Three Months Ended										Three Months Ended						Three Months Ended
	September 30,					September 30,										September 30,						September 30,
(In thousands)	2015		2014			2015					2014					2015			2014			2015			2014
Beginning balance	$	46	$	449		$	(1,212	)			$	(750	)			$	(1	)	$	111		$	(1,167	)	$	(190	)
Other comprehensive income (loss) before reclassifications	20		(246		)	—					—					40			(53		)	60			(299		)
Amounts reclassified from accumulated other comprehensive income	—		—			64			(1	)	15			(1	)	—			—			64			15
Net-current period other comprehensive income (loss)	20		(246		)	64					15					40			(53		)	124			(284		)
Ending balance	$	66	$	203		$	(1,148	)			$	(735	)			$	39		$	58		$	(1,043	)	$	(474	)

_______________

(1) This component of accumulated other comprehensive income is included in the computation of net periodic pension cost for the three months ended September 30, 2015 and 2014.

Changes in accumulated other comprehensive income (loss) for the nine months ended September 30, 2015 and 2014:

	Unrealized Gains and Losses on Marketable Securities						Defined Benefit Pension Items										Foreign Currency Items					Total
	Nine Months Ended						Nine Months Ended										Nine Months Ended					Nine Months Ended
	September 30,						September 30,										September 30,					September 30,
(In thousands)	2015			2014			2015					2014					2015		2014			2015			2014
Beginning balance	$	83		$	210		$	(1,240	)			$	(780	)			$	21	$	100		$	(1,136	)	$	(470	)
Other comprehensive income (loss) before reclassifications	(17		)	(7		)	—					—					18		(42		)	1			(49		)
Amounts reclassified from accumulated other comprehensive income	—			—			92			(1	)	45			(1	)	—		—			92			45
Net-current period other comprehensive income (loss)	(17		)	(7		)	92					45					18		(42		)	93			(4		)
Ending balance	$	66		$	203		$	(1,148	)			$	(735	)			$	39	$	58		$	(1,043	)	$	(474	)

_______________

(1) This component of accumulated other comprehensive income is included in the computation of net periodic pension cost for the nine months ended September 30, 2015 and 2014.

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CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 26,446	$ 45,190
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	12,235	11,849
Amortization of intangibles	5,247	4,723
Loss on sale of property and equipment	270	170
Stock-based compensation expense	11,502	10,670
Amortization of premium on marketable securities	809	1,296
Deferred income taxes	152	(782)
Increase in accounts receivable allowances	128	75
Excess tax benefit from employee stock plans	0	(437)
Tax benefit (deficiency) associated with employee stock plans	(189)	815
Change in operating assets and liabilities:
Accounts receivable	888	1,933
Inventories	9,995	(14,639)
Prepaid expenses and other assets	4,278	9,955
Accounts payable	(2,035)	2,509
Taxes payable and accrued liabilities	(3,579)	(3,257)
Deferred income on sales to distributors	1,241	3,017
Net cash provided by operating activities	67,388	73,087
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchases of property and equipment	(7,619)	(17,394)
Payment for purchase of building (Note 10)	(10,389)	0
Payment for acquisition, net of cash acquired (Note 10)	(15,549)	0
Other assets	0	(1,261)
Purchases of marketable securities	(14,933)	(45,269)
Proceeds from sales and maturities of marketable securities	37,459	0
Net cash used in investing activities	(11,031)	(63,924)
CASH FLOWS FROM FINANCING ACTIVITIES:
Issuance of common stock under employee stock plans	6,902	13,104
Repurchase of common stock	(53,731)	(45,258)
Payments of dividends to stockholders	(10,501)	(9,654)
Excess tax benefit from employee stock plans	0	437
Net cash used in financing activities	(57,330)	(41,371)
NET DECREASE IN CASH AND CASH EQUIVALENTS	(973)	(32,208)
CASH AND CASH EQUIVALENTS AT BEGINNING OF PERIOD	60,708	92,928
CASH AND CASH EQUIVALENTS AT END OF PERIOD	59,735	60,720
SUPPLEMENTAL DISCLOSURE OF NON-CASH INVESTING AND FINANCING ACTIVITIES:
Unpaid property and equipment	3,216	4,359
Loan applied to CamSemi purchase price (Note 10)	6,600	0
SUPPLEMENTAL DISCLOSURE OF CASH FLOW INFORMATION:
Cash paid (refund) for income taxes, net	$ 1,007	$ (3,707)

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CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) (PARENTHETICAL) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Statement of Financial Position [Abstract]
Accounts receivable, allowance	$ (319)	$ (191)

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ACQUISITIONS

9 Months Ended

Sep. 30, 2015

Business Combinations [Abstract]

Acquisitions

ACQUISITIONS:

Cambridge Semiconductor Limited

In December 2014, the Company entered into a loan agreement with Cambridge Semiconductor Limited ("CamSemi"), a UK company, in which $6.6 million was outstanding as of December 31, 2014. The estimated fair value of the loan approximated the carrying value of $6.6 million, as the loan was outstanding for less than a month and the interest rate approximated a market rate for such a loan. The loan was in anticipation of a definitive agreement the Company entered into to acquire CamSemi in January 2015.

On January 2, 2015, the Company acquired 100% of the shares outstanding of CamSemi for total consideration of approximately $23.3 million, of which $16.7 million was paid in cash and $6.6 million was applied against the outstanding loan owed to the Company. The acquisition-related costs for the purchase of CamSemi were $0.2 million in the nine months ended September 30, 2015, and $0.8 million in the three months ended December 31, 2014. The acquisition has been accounted for using the acquisition method of accounting in accordance with ASC 805 - Business Combinations. Goodwill is not expected to be deductible for tax purposes.

CamSemi was acquired to accelerate the Company's product-development efforts for the low-power market. The acquisition also broadens the Company's technology and product portfolio for low-power applications, particularly in the mobility and light-emitting diode ("LED") lighting markets. The purchase price allocated to goodwill in the acquisition (as noted in the purchase price allocation below) is related largely to synergies and economies of scale expected from combining the operations of CamSemi with those of the Company.

The following table summarizes the purchase price and preliminary estimated fair values of the assets acquired and the liabilities assumed as of January 2, 2015. The allocation of the purchase price is preliminary as certain pre-acquisition liabilities and corporate taxes are still being finalized and may be adjusted should further information regarding events or circumstances existing as of the acquisition date become available.

(In thousands)		Total Amount
Assets Acquired
	Cash	$	1,134
	Accounts receivable	1,891
	Inventories	1,409
	Prepaid expenses and other current assets	408
	Tax receivable	1,093
	Intangible assets:
	Developed technology	6,600
	Customer relationships	2,420
	Goodwill	11,250
	Total assets acquired	26,205
Liabilities Assumed
	Current liabilities	1,832
	Taxes payable	1,090
	Total liabilities assumed	2,922
	Total purchase price	$	23,283

The following table represents details of the purchased intangible assets:

	Fair Value Amount (in thousands)		Estimated Useful Life (in years)
Developed technology	$	6,600	3	-	7
Customer relationships	2,420		5
Total acquired CamSemi intangibles	$	9,020

The fair value of the identifiable intangible assets, developed technology and customer relationships, were determined based on the following approach.

Developed Technology.The income approach was used to value the acquired developed technology. Revenue attributable to the Company's technology was estimated based on expected evolution of the technology over time. Expenses were assumed to reflect the costs necessary to support the developed technology.  The present value was capitalized as developed technology as of the acquisition date and is being amortized using a straight-line method to cost of revenues over the estimated life of 3 - 7 years.

Customer Relationships. An intangible customer relationship asset was recognized to the extent that the Company was expected to benefit from future revenues reasonably anticipated given the historical customer relationships and operating practices of CamSemi. In order to determine the fair value of the customer relationships, the Company's analysis assumed that the Company would immediately benefit from the economics generated by CamSemi's existing customer relationships.  This amount was reduced by the potential impact given no past customer relationships and the assumption that the Company could reacquire the customer relationships and ramp up to a similar level of revenue within two years.  The fair value of customer relationships was capitalized as of the acquisition date and is being amortized on a straight line basis to sales and marketing expenses over the estimated life of 5 years.

Pro forma results of operations for this acquisition have not been presented because it is not material to the Company’s condensed consolidated financial statements.

Corporate Headquarters Building

In August, 2015, the Company purchased a building adjacent to the corporate headquarters in San Jose, California to support the overall growth of the business. The purchase has been accounted for using the acquisition method of accounting in accordance with ASC 805 - Business Combinations, as the building had existing rental income resulting from in-place lease agreements with third-party tenants. The aggregate purchase price of $10.4 million, funded with cash on hand, was allocated as follows: $3.5 million for land, $6.3 million for building and improvements, $0.7 million for in-place leases and $(0.1) million for liabilities assumed. The building and improvements are being depreciated on a straight-line basis over an estimated useful life of up to 30 years. Additionally, as a result of the purchase, the Company acquired existing third-party leases that were valued as in-place lease intangible assets and are being amortized over the weighted average estimated life of 2 years. The valuation of the acquired in-place leases were estimated by the Company based on the amount of avoided cash outflows necessary to originate such leases. Acquisition-related costs in connection with the building purchase were included in other income, net in the consolidated statements of income and were not material for the periods presented. The allocation of the purchase price is preliminary and may be adjusted should further information regarding events or circumstances existing as of the acquisition date become available.

Rental income from the third-party leases, and the proportionate share of building expenses for those leases, are included in other income, net in the consolidated statements of income from the date of acquisition. These amounts were not material for the periods presented.

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Document and Entity Information Document - shares	9 Months Ended
	Sep. 30, 2015	Oct. 16, 2015
Document and Entity Information [Abstract]
Entity Registrant Name	POWER INTEGRATIONS INC
Entity Central Index Key	0000833640
Trading Symbol	POWI
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Document Type	10-Q
Document Period End Date	Sep. 30, 2015
Document Fiscal Year Focus	2015
Document Fiscal Period Focus	Q3
Amendment Flag	false
Entity Common Stock, Shares Outstanding		28,430,305

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COMMITMENTS

9 Months Ended

Sep. 30, 2015

Commitments and Contingencies Disclosure [Abstract]

COMMITMENTS

COMMITMENTS:

Supplier Agreements

Under the terms of the Company's wafer-supply agreements with Seiko Epson Corporation ("Epson"), and ROHM Lapis Semiconductor Co., Ltd. ("Lapis") the wafers purchased from these suppliers are priced in U.S. dollars; however, these agreements also allow for mutual sharing of the impact of the exchange rate fluctuation between Japanese yen and the U.S. dollar on future purchases. Each year, the Company's management and these two suppliers review and negotiate future pricing; the negotiated pricing is denominated in U.S. dollars but is subject to contractual exchange rate provisions. The fluctuation in the exchange rate is shared equally between the Company and each of these suppliers on future purchases.

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CONDENSED CONSOLIDATED STATEMENTS OF INCOME (Unaudited) - USD ($) shares in Thousands, $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Income Statement [Abstract]
NET REVENUES		$ 88,878	$ 90,144	$ 256,700	$ 262,202
COST OF REVENUES		44,717	41,092	126,229	118,437
GROSS PROFIT		44,161	49,052	130,471	143,765
OPERATING EXPENSES:
Research and development		13,888	13,458	43,693	41,314
Sales and marketing		11,129	11,564	35,701	35,906
General and administrative		7,361	7,155	23,133	22,614
Total operating expenses		32,378	32,177	102,527	99,834
INCOME FROM OPERATIONS		11,783	16,875	27,944	43,931
OTHER INCOME
Other income, net		428	381	219	836
Total other income		428	381	219	836
INCOME BEFORE INCOME TAXES		12,211	17,256	28,163	44,767
PROVISION FOR (BENEFIT FROM) INCOME TAXES		698	1,145	1,717	(423)
NET INCOME		$ 11,513	$ 16,111	$ 26,446	$ 45,190
EARNINGS PER SHARE:
Basic (in dollars per share)		$ 0.40	$ 0.54	$ 0.91	$ 1.50
Diluted (in dollars per share)	[1]	$ 0.39	$ 0.52	$ 0.89	$ 1.46
SHARES USED IN PER SHARE CALCULATION:
Basic (in shares)		28,855	30,013	29,175	30,186
Diluted (in shares)		29,298	30,757	29,856	31,053

[1] The Company includes the shares underlying performance-based awards in the calculation of diluted earnings per share if the performance conditions have been satisfied as of the end of the reporting period and excludes such shares when the necessary conditions have not been met. The Company has excluded the shares underlying the 2015 and 2014 awards in the 2015 and 2014 calculations, respectively, as those shares were not contingently issuable as of the end of the period.

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INVENTORIES

9 Months Ended

Sep. 30, 2015

Inventory Disclosure [Abstract]

INVENTORIES

INVENTORIES:

Inventories (which consist of costs associated with the purchases of wafers from domestic and offshore foundries and of packaged components from offshore assembly manufacturers, as well as internal labor and overhead associated with the testing of both wafers and packaged components) are stated at the lower of cost (first-in, first-out) or market. Provisions, when required, are made to reduce excess and obsolete inventories to their estimated net realizable values.

Inventories consist of the following:

(In thousands)	September 30, 2015		December 31, 2014
Raw materials	$	18,661	$	21,127
Work-in-process	14,659		14,643
Finished goods	22,119		28,255
Total	$	55,439	$	64,025

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FAIR VALUE MEASUREMENTS

9 Months Ended

Sep. 30, 2015

Fair Value Disclosures [Abstract]

FAIR VALUE MEASUREMENTS

FAIR VALUE MEASUREMENTS:

ASC 820-10, Fair Value Measurements, clarifies that fair value is an exit price, representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. As such, fair value is a market-based measurement that should be determined based on assumptions that market participants would use in pricing an asset or liability. As a basis for considering such assumptions, ASC 820-10 establishes a three-tier value hierarchy, which prioritizes the inputs used in measuring fair value as follows: (Level 1) observable inputs such as quoted prices for identical assets in active markets; (Level 2) inputs other than the quoted prices in active markets that are observable either directly or indirectly; and (Level 3) unobservable inputs in which there is little or no market data, which requires the Company to develop its own assumptions. This hierarchy requires the Company to use observable market data, when available, and to minimize the use of unobservable inputs when determining fair value.

The Company's cash equivalents and short-term marketable securities are classified within Level 1 or Level 2 of the fair-value hierarchy because they are valued using quoted market prices, broker or dealer quotations, or alternative pricing sources with reasonable levels of price transparency. The type of instrument valued based on quoted market prices in active markets primarily includes money market securities. This type of instrument is generally classified within Level 1 of the fair-value hierarchy. The types of instruments valued based on other observable inputs (Level 2 of the fair-value hierarchy) generally include investment-grade corporate bonds, government, state, municipal and provincial obligations and commercial paper. Such types of investments are valued by using a multi-dimensional relational model, the inputs are primarily benchmark yields, reported trades, broker/dealer quotes, issuer spreads, two-sided markets, benchmark securities, bids, offers, and reference data including market research publications. The Company's investments classified as Level 1 and Level 2 are available-for-sale investments, and were recorded at fair market value.

The fair-value hierarchy of the Company's marketable securities at September 30, 2015, and December 31, 2014, was as follows:

	Fair Value Measurement at
	September 30, 2015
(In thousands)	Total Fair Value		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)
Commercial paper	$	18,019	$	—	$	18,019
Money market funds	11,742		11,742		—
Corporate securities	78,777		—		78,777
Total	$	108,538	$	11,742	$	96,796

	Fair Value Measurement at
	December 31, 2014
(In thousands)	Total Fair Value		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)
Money market funds	$	3,370	$	3,370	$	—
Corporate securities	114,575		—		114,575
Total	$	117,945	$	3,370	$	114,575

The Company did not transfer any investments between Level 1 and Level 2 of the fair-value hierarchy in the nine months ended September 30, 2015, and the twelve months ended December 31, 2014.

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SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)

9 Months Ended

Sep. 30, 2015

Accounting Policies [Abstract]

Cash and Cash Equivalents

Cash and Cash Equivalents

The Company considers cash invested in highly liquid financial instruments with maturities of three months or less at the date of purchase to be cash equivalents.

Marketable Securities

Marketable Securities

The Company generally holds securities until maturity; however, they may be sold under certain circumstances including, but not limited to, when necessary for the funding of acquisitions, stock repurchases and other strategic investments. As a result the Company classifies its investment portfolio as available-for-sale. The Company classifies all investments with a maturity date greater than three months at the date of purchase as short-term marketable securities in its Condensed Consolidated Balance Sheets. As of September 30, 2015, and December 31, 2014, the Company's marketable securities consisted primarily of highly liquid corporate securities, commercial paper and other high-quality commercial securities.

Revenue Recognition

Revenue Recognition

Product revenues consist of sales to original equipment manufacturers (“OEMs”), merchant power supply manufacturers and distributors. Approximately 76% of the Company's net product sales were made to distributors in the ninemonths ended September 30, 2015, and 75%in the twelve months ended December 31, 2014. The Company applies the provisions of Accounting Standard Codification (“ASC”) 605-10 (“ASC 605-10”) and all related appropriate guidance. Revenue is recognized when all of the following criteria have been met: (1) persuasive evidence of an arrangement exists, (2) delivery has occurred, (3) the price is fixed or determinable, and (4) collectability is reasonably assured. Customer purchase orders are generally used to determine the existence of an arrangement. Delivery is considered to have occurred when title and risk of loss have transferred to the Company's customer. The Company evaluates whether the price is fixed or determinable based on the payment terms associated with the transaction and whether the sales price is subject to refund or adjustment. With respect to collectability, the Company performs credit checks for new customers and performs ongoing evaluations of its existing customers' financial condition and requires letters of credit whenever deemed necessary.

Sales to international OEM customers and merchant power supply manufacturers that are shipped from the Company's facility in California are pursuant to “delivered at frontier” (“DAF”) shipping terms. As such, title to the product passes to the customer when the shipment reaches the destination country and revenue is recognized upon the arrival of the product in that country. Sales to international OEMs and merchant power supply manufacturers for shipments from the Company's facility outside of the United States are pursuant to “EX Works” ("EXW") shipping terms, meaning that title to the product transfers to the customer upon shipment from the Company's foreign warehouse. Shipments to OEMs and merchant power supply manufacturers in the Americas are pursuant to “free on board” (“FOB”) point of origin shipping terms, meaning that title is passed to the customer upon shipment. Revenue is recognized upon title transfer for sales to OEMs and merchant power supply manufacturers, assuming all other criteria for revenue recognition are met.

Sales to most of the Company's distributors are made under terms allowing certain price adjustments and rights of return on the Company's products held by its distributors. As a result of these rights, the Company defers the recognition of revenue and the costs of revenues derived from sales to distributors until the Company's distributors report that they have sold the Company's products to their customers. The Company's recognition of such distributor revenue is based on point of sale reports received from the distributors, at which time the price is no longer subject to adjustment and is fixed, and the products are no longer subject to return to the Company except pursuant to warranty terms. The gross profit that is deferred as a result of this policy is reflected as “deferred income on sales to distributors” in the accompanying condensed consolidated balance sheets. The total deferred revenue as of September 30, 2015, and December 31, 2014, was approximately $28.4 million and $25.0 million, respectively. The total deferred cost as of September 30, 2015, and December 31, 2014, was approximately $11.9 million and $9.8 million, respectively.

Frequently, distributors need to sell at a price lower than the standard distribution price in order to win business. At or soon after the distributor invoices its customer, the distributor submits a “ship and debit” price adjustment claim to the Company to adjust the distributor's cost from the standard price to the pre-approved lower price. After verification by the Company, a credit memo is issued to the distributor for the ship and debit claim. The Company maintains a reserve for unprocessed claims and future ship and debit price adjustments. The reserve appears as a reduction to accounts receivable in the Company's accompanying consolidated balance sheets. To the extent future ship and debit claims significantly exceed amounts estimated, there could be a material impact on the deferred revenue and deferred margin ultimately recognized. To evaluate the adequacy of its reserves, the Company analyzes historical ship and debit payments and levels of inventory in the distributor channels.

Sales to certain of the Company's distributors are made under terms that do not include rights of return or price concessions after the product is shipped to the distributor. Accordingly, product revenue is recognized upon shipment and title transfer assuming all other revenue recognition criteria are met.

Use of Estimates

Use of Estimates

The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosures of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. On an ongoing basis, the Company evaluates its estimates, including those related to revenue recognition, income tax, stock-based compensation and inventories. These estimates are based on historical facts and various other assumptions that the Company believes to be reasonable at the time the estimates are made.

Stock-Based Compensation

Stock-Based Compensation

The Company applies the provisions of ASC 718-10. Under the provisions of ASC 718-10, the Company recognizes the fair value of stock-based compensation in financial statements over the requisite service period of the individual grants, which generally equals a four year vesting period. The Company uses estimates of volatility, expected term, risk-free interest rate, dividend yield and forfeitures in determining the fair value of these awards and the amount of compensation expense to recognize. The Company uses the straight-line method to amortize all stock awards granted over the requisite service period of the award, and uses historical data to estimate pre-vesting forfeitures, recognizing expense only for those awards that are expected to vest.

Determining Fair Value of Stock Options

The Company uses the Black-Scholes valuation model for valuing stock option grants using the following assumptions and estimates:

ExpectedVolatility. The Company calculates expected volatility based on the historical price volatility of the Company's stock.

Expected Term. The Company utilizes a model which uses historical exercise, cancellation and outstanding option data to calculate the expected term of stock option grants.

Risk-Free Interest Rate. The Company bases the risk-free interest rate used in the Black-Scholes valuation model on the implied yield available on a U.S. Treasury note with a term approximately equal to the expected term of the underlying grants.

Dividend Yield. The dividend yield was calculated by dividing the annual dividend by the average closing price of the Company's common stock on a quarterly basis.

Segment Reporting

Segment Reporting

The Company is organized and operates as one reportable segment, the design, development, manufacture and marketing of integrated circuits and related components for use primarily in the high-voltage power-conversion market. The Company's chief operating decision maker, the Chief Executive Officer, reviews financial information presented on a consolidated basis for purposes of making operating decisions and assessing financial performance.

Earnings Per Share

Basic earnings per share are calculated by dividing net income by the weighted-average shares of common stock outstanding during the period. Diluted earnings per share are calculated by dividing net income by the weighted-average shares of common stock and dilutive common equivalent shares outstanding during the period. Dilutive common equivalent shares included in this calculation consist of dilutive shares issuable upon the assumed exercise of outstanding common stock options, the assumed vesting of outstanding restricted stock units and both short- and long-term performance-based awards, and the assumed issuance of awards under the stock purchase plan, as computed using the treasury stock method.

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LEGAL PROCEEDINGS AND CONTINGENCIES

9 Months Ended

Sep. 30, 2015

Commitments and Contingencies Disclosure [Abstract]

LEGAL PROCEEDINGS AND CONTINGENCIES

LEGAL PROCEEDINGS AND CONTINGENCIES:

From time to time in the ordinary course of business, the Company becomes involved in lawsuits, or customers and distributors may make claims against the Company. In accordance with ASC 450-10, the Company makes a provision for a liability when it is both probable that a liability has been incurred and the amount of the loss can be reasonably estimated.

On October 20, 2004, the Company filed a complaint against Fairchild Semiconductor International, Inc. and Fairchild Semiconductor Corporation (referred to collectively as "Fairchild") in the United States District Court for the District of Delaware. In its complaint, the Company alleged that Fairchild has and is infringing four of Power Integrations' patents pertaining to pulse width modulation (“PWM”) integrated circuit devices. Fairchild denied infringement and asked for a declaration from the court that it does not infringe any Power Integrations patent and that the patents are invalid. The Court issued a claim construction order on March 31, 2006 which was favorable to the Company. The Court set a first trial on the issues of infringement, willfulness and damages for October 2, 2006. At the close of the first trial, on October 10, 2006, the jury returned a verdict in favor of the Company finding all asserted claims of all four patents-in-suit to be willfully infringed by Fairchild and awarding $34.0 million in damages. Fairchild raised defenses contending that the asserted patents are invalid or unenforceable, and the Court held a second trial on these issues beginning on September 17, 2007. On September 21, 2007, the jury returned a verdict in the Company's favor, affirming the validity of the asserted claims of all four patents-in-suit. Fairchild submitted further materials on the issue of enforceability along with various other post-trial motions, and the Company filed post-trial motions seeking a permanent injunction and increased damages and attorneys' fees, among other things. On September 24, 2008, the Court denied Fairchild's motion regarding enforceability and ruled that all four patents are enforceable. On December 12, 2008, the Court ruled on the remaining post-trial motions, including granting a permanent injunction, reducing the damages award to $6.1 million, granting Fairchild a new trial on the issue of willful infringement in view of an intervening change in the law, and denying the Company's motion for increased damages and attorneys' fees with leave to renew the motion after the resolution of the issue of willful infringement. On December 22, 2008, at Fairchild's request, the Court temporarily stayed the permanent injunction for 90 days. On January 12, 2009, Fairchild filed a notice of appeal challenging the Court's refusal to enter a more permanent stay of the injunction, and Fairchild filed additional motions requesting that both the Federal Circuit and the District Court extend the stay of injunction. The District Court temporarily extended the stay pending the Federal Circuit ruling on Fairchild's pending motion, but the Federal Circuit dismissed Fairchild's appeal and denied its motion on May 5, 2009, and the District Court issued an order on May 13, 2009 confirming the reinstatement of the permanent injunction as originally entered in December 2008. On June 22, 2009, the Court held a brief bench re-trial on the issue of willful infringement. On July 22, 2010, the Court found that Fairchild willfully infringed all four of the asserted patents, and the Court also invited briefing on enhanced damages and attorneys' fees. Fairchild also filed a motion requesting that the Court amend its findings regarding willfulness. On January 18, 2011, the Court denied Fairchild's request to amend the findings regarding Fairchild's willful infringement and doubled the damages award against Fairchild but declined to award attorneys' fees. On February 3, 2011, the Court entered final judgment in favor of the Company for a total damages award of $12.9 million. Fairchild filed a notice of appeal challenging the final judgment and a number of the underlying rulings, and the Company filed a cross-appeal seeking to increase the damages award. The appeal was argued on January 11, 2012, and the Federal Circuit issued a mixed ruling on March 26, 2013, affirming Fairchild's infringement of certain claims that support the basis for the permanent injunction while reversing, vacating, and remanding the findings with respect to other claims, including the Company's claim for damages. The Company filed a petition seeking Supreme Court review of the Federal Circuit’s ruling on damages issues, and the Supreme Court called for a response from Fairchild but ultimately declined to review the case. On remand, the Company intends to pursue its claim for financial compensation based on Fairchild's infringement.

On May 9, 2005, the Company filed a Complaint with the U.S. International Trade Commission (“ITC”) under section 337 of the Tariff Act of 1930, as amended, 19 U.S.C. section 1337 against System General (“SG”). The Company filed a supplement to the complaint on May 24, 2005. The Company alleged infringement of its patents pertaining to PWM integrated circuit devices produced by SG, which are used in power conversion applications such as power supplies for computer monitors. The Commission instituted an investigation on June 8, 2005 in response to the Company's complaint. SG filed a response to the ITC complaint asserting that the patents-in-suit were invalid and not infringed. The Company subsequently and voluntarily narrowed the number of patents and claims in suit, which proceeded to a hearing. The hearing on the investigation was held before the Administrative Law Judge (“ALJ”) from January 18 to January 24, 2006. Post-hearing briefs were submitted and briefing concluded February 24, 2006. The ALJ's initial determination was issued on May 15, 2006. The ALJ found all remaining asserted claims valid and infringed, and recommended the exclusion of the infringing products as well as certain downstream products that contain the infringing products. After further briefing, on June 30, 2006, the Commission decided not to review the initial determination on liability, but did invite briefs on remedy, bonding and the public interest. On August 11, 2006, the Commission issued an order excluding from entry into the United States the infringing SG PWM chips, and any liquid-crystal-display ("LCD") computer monitors, AC printer adapters and sample/demonstration circuit boards containing an infringing SG chip. The U.S. Customs Service is authorized to enforce the exclusion order. On October 11, 2006, the presidential review period expired without any action from the President, and the ITC exclusion order is now in full effect. SG appealed the ITC decision, and on November 19, 2007, the Federal Circuit affirmed the ITC's findings in all respects. On October 27, 2008, SG filed a petition to modify the exclusion order in view of a recent Federal Circuit opinion in an unrelated case, and the Company responded to oppose any modification, but the Commission modified the exclusion order on February 27, 2009. Nevertheless, the exclusion order still prohibits SG and related entities from importing the infringing SG chips and any LCD computer monitors, AC printer adapters, and sample/demonstration circuit boards containing an infringing SG chip.

On May 23, 2008, the Company filed a complaint against Fairchild Semiconductor International, Inc., Fairchild Semiconductor Corporation, and Fairchild's wholly owned subsidiary System General Corporation (referred to collectively as “Fairchild”), in the United States District Court for the District of Delaware. In its complaint, the Company alleged that Fairchild has infringed and is infringing three patents pertaining to power supply controller integrated circuit devices. Fairchild answered the Company's complaint on November 7, 2008, denying infringement and asking for a declaration from the Court that it does not infringe any Power Integrations patent and that the patents are invalid and unenforceable. Fairchild's answer also included counterclaims accusing the Company of infringing three patents pertaining to primary side power conversion integrated circuit devices. Fairchild had earlier brought these same claims in a separate suit against the Company, also in Delaware, which Fairchild dismissed in favor of adding its claims to the Company's already pending suit against Fairchild. The Company has answered Fairchild's counterclaims, denying infringement and asking for a declaration from the Court that it does not infringe any Fairchild patent and that the Fairchild patents are invalid. Fairchild also filed a motion to stay the case, but the Court denied that motion on December 19, 2008. On March 5, 2009, Fairchild filed a motion for summary judgment to preclude any recovery for post-verdict sales of parts found to infringe in the parties' other ongoing litigation, described above, and the Company filed its opposition and a cross-motion to preclude Fairchild from re-litigating the issues of infringement and damages for those same products. On June 26, 2009, the Court held a hearing on the parties' motions, and on July 9, 2009 the Court issued an order denying the parties' motions but staying proceedings with respect to the products that were found to infringe and which are subject to the injunction in the other Delaware case between the parties pending the entry of final judgment in that case; those products are expected to be addressed in the context of the parties’ remand proceedings following the appeal in their earlier litigation in Delaware, and the remainder of the case is proceeding. On December 18, 2009, the Court issued an order construing certain terms in the asserted claims of the Company's and Fairchild's patents in suit. Following the Court's ruling on claim construction, Fairchild withdrew its claim related to one of its patents and significantly reduced the number of claims asserted for the remaining two patents. The parties thereafter filed and argued a number of motions for summary judgment, and the Court denied the majority of the parties' motions but granted the Company's motion to preclude Fairchild from re-arguing validity positions that were rejected in the prior case between the parties. Because the assigned Judge retired at the end of July 2010, the case was re-assigned to a different Judge, and the Court vacated the trial schedule and had the parties provide their input on the appropriate course of action. The Court thereafter set a trial schedule with the jury trial on infringement and validity to begin in July 2011. On April 18, 2011, the Court rescheduled the trial to begin in January 2012, and on June 2, 2011, the Court moved the trial date to April 2012 to permit the parties to address another patent the Company accused Fairchild of infringing. Following a trial in April 2012, the jury returned a verdict finding that Fairchild infringes two of the Company's patents, that Fairchild has induced others to infringe the Company's patents, and also upheld the validity of the infringed patents. Of the two remaining counterclaim patents Fairchild asserted in the case, one was found not to be infringed, but the jury found the second patent to be infringed by a limited number of the Company's products, although the jury further found the Company did not induce infringement by any customers, including customers outside the United States. On March 29, 2013, the District Court denied most of the parties' post-trial motions on liability but granted the Company's motion for judgment as a matter of law finding that Fairchild infringed another of the Company's patents. On April 25, 2013, the Court denied both parties' motions regarding the unenforceability of each other's patents. The Company intends to challenge adverse findings on appeal; nevertheless, the Company estimates that even if the verdict on Fairchild's patent were ultimately upheld, the sales potentially impacted would amount to only about 0.3% of the Company's revenues. The Company requested an injunction preventing further infringement of its own patents by Fairchild, and Fairchild requested an injunction as well. Following a hearing on the issue in June 2014, the Court denied Fairchild's request for an injunction against the Company and granted the Company's request for an injunction against Fairchild. On January 13, 2015, the District Court entered final judgment on the liability and validity issues discussed above, and both parties filed appeals with the Federal Circuit, for which briefing should be completed later this year. The Company is also seeking financial damages, as well as enhanced damages for willful infringement, issues to be decided in separate proceedings at a later date.

On June 28, 2004, the Company filed a complaint for patent infringement in the U.S. District Court, Northern District of California, against SG Corporation, a Taiwanese company, and its U.S. subsidiary. The Company's complaint alleged that certain integrated circuits produced by SG infringed and continue to infringe certain of its patents. On June 10, 2005, in response to the initiation of the International Trade Commission (ITC) investigation discussed above, the District Court stayed all proceedings. Subsequent to the completion of the ITC proceedings, the District Court temporarily lifted the stay and scheduled a case management conference. On December 6, 2006, SG filed a notice of appeal of the ITC decision as discussed above. In response, and by agreement of the parties, the District Court vacated the scheduled case management conference and renewed the stay of proceedings pending the outcome of the Federal Circuit appeal of the ITC determination. On November 19, 2007, the Federal Circuit affirmed the ITC's findings in all respects, and SG did not file a petition for review. The parties subsequently filed a motion to dismiss the District Court case without prejudice. On November 4, 2009, the Company re-filed its complaint for patent infringement against SG and its parent corporations, Fairchild Semiconductor International, Inc. and Fairchild Semiconductor Corporation, to address their continued infringement of patents at issue in the original suit that recently emerged from SG requested reexamination proceedings before the U.S. Patent and Trademark Office (USPTO). The Company seeks, among other things, an order enjoining SG and Fairchild from infringing the Company's patents and an award of damages resulting from the alleged infringement. Fairchild has denied infringement and asked for a declaration from the Court that it does not infringe any Power Integrations patent, that the patents are invalid, and that one of the two of the Company's patents now at issue in the case is unenforceable. On May 5, 2010, SG and Fairchild filed an amended answer including counterclaims accusing the Company of infringing two patents, and since that time Fairchild has withdrawn its claim for infringement of one of the patents it originally asserted against the Company but added another patent to the case over the Company's objections; the Company contests these claims vigorously. Both parties filed summary judgment motions and challenges to each other’s experts’ testimony, and the Court granted the Company’s motion for summary judgment of non-infringement with respect to one of Fairchild’s two patents. Following a trial on the remaining claims in February 2014, the jury returned a verdict in the Company’s favor, affirming the validity of the asserted claims of the Company’s patents-in-suit, finding that SG and Fairchild infringed the Company’s asserted patents and induced infringement by others, and awarding $105.0 million in damages. Although the jury awarded damages, at this stage of the proceedings the Company cannot state the amount, if any, it might ultimately recover from Fairchild, and no benefits have been recorded in the Company’s condensed consolidated financial statements as a result of the damages verdict. The Jury also rejected Fairchild’s remaining counterclaims for infringement against the Company. Fairchild challenged these rulings in post-trial motions, but the judge confirmed the jury’s determinations on infringement and damages, although the Court declined to find Fairchild’s infringement willful. Fairchild also pressed its unenforceability claim with respect to one of the two patents it was found to infringe in post-trial briefing, but the Court rejected Fairchild’s unenforceability claim. Fairchild also requested reconsideration of the damages determinations, and the Court granted a new trial with respect to damages but none of the other issues addressed in the previous trial, with the retrial scheduled for December 2015. The parties recently completed pretrial proceedings challenging each other’s experts, and the Court granted portions of each party’s motions limiting the scope of expert testimony for purposes of the damages retrial, but neither party was successful in their efforts to prevent the other side’s experts from testifying at trial. Further pretrial proceedings will take place over the coming months.

In February 2010, Fairchild and System General ("SG") filed suits for patent infringement against the Company, Power Integrations Netherlands B.V., and representative offices of Power Integrations Netherlands in Shanghai and Shenzhen with the Suzhou Intermediate Court in the People's Republic of China. The suits assert four Chinese patents and seek an injunction and damages of approximately $19.0 million. Power Integrations Netherlands filed invalidation proceedings for all four asserted SG patents in the People's Republic of China Patent Reexamination Board (PRB) of the State Intellectual Property Office (SIPO), and all four challenges were accepted by the PRB, with hearings conducted in September 2010. In early January 2012, the Company received rulings from the PRB invalidating the majority of the claims Fairchild asserted in litigation. The Suzhou Court conducted evidentiary hearings in 2012 and issued rulings in late December 2012, finding that the Company did not infringe any of the asserted patents. Fairchild filed appeals challenging the Suzhou Court's non-infringement rulings, and the appeals court in Nanjing held further hearings in the infringement proceedings, but Fairchild has since dismissed its appeals, bringing the infringement proceedings to a close in the first quarter of 2015.

On July 11, 2011, the Company filed a complaint in the U.S. District Court, District of Columbia, against David Kappos in his capacity as Director of the United States Patent and Trademark Office (“PTO”) as part of the ongoing reexamination proceedings related to one of the patents asserted against Fairchild and SG in the Delaware litigation described above. The Company filed a motion for summary judgment on a preliminary jurisdictional issue, and the PTO filed a cross-motion to dismiss on this same issue; briefing on those motions was completed in October, 2011. On November 18, 2013, the Court granted the PTO’s motion and transferred the case to the Federal Circuit, where additional briefing took place. Following a hearing in May 2015, the Federal Circuit ruled in the Company's favor on August 12, 2015, overturning the PTO's claim construction and remanding the case for further proceedings.

On May 1, 2012, Fairchild Semiconductor Corporation and Fairchild's wholly-owned subsidiary, System General Corporation (referred to collectively as “Fairchild”), filed a complaint against the Company in the United States District Court for the District of Delaware. In its complaint, Fairchild alleged that the Company has infringed and is infringing four patents pertaining to power conversion integrated circuit devices. The Company answered Fairchild's complaint, denying infringement and asking for a declaration from the Court that it does not infringe any Fairchild patent and that the Fairchild patents are invalid, and the Company also asserted counterclaims against Fairchild for infringement of five of the Company's patents. Fairchild has withdrawn its claim for infringement of one of the patents it asserted against the Company after the Company's preliminary challenge. The parties streamlined their contentions in view of the Court's pretrial rulings, and following a trial in late May and early June 2015, a jury returned a verdict finding that Fairchild infringed one of the Company's patents, that Fairchild has induced and contributed to others' infringement of the Company's patent, and that the Company induced infringement of a Fairchild patent that was previously found infringed in the 2012 trial described above, with a damages award of $2.4 million in favor of Fairchild. However, in parallel proceedings the Patent Office has rejected all of the asserted claims of the one Fairchild patent found infringed, determinations that Fairchild is challenging on appeal, and the Court rejected Fairchild’s earlier request for an injunction based on those same claims. Both parties have filed post-trial motions and challenges to various portions of the jury verdicts, and the Court is expected to address the first wave of post-trial motions over the coming months. The Company believes it has valid defenses against the $2.4 million award in favor of Fairchild, and therefore has not recorded a loss in its financial statements at this time.

On October 21, 2015, the Company filed a complaint for patent infringement against Fairchild Semiconductor Corporation, Fairchild Semiconductor International, Inc., and wholly-owned subsidiary Fairchild (Taiwan) Corporation (referred to collectively as “Fairchild”) to address Fairchild’s continued infringement of two patents Fairchild was previously found to infringe in the three District Court cases the Company brought against Fairchild discussed above. In each of the three prior cases, Fairchild was found to infringe one of the patents at issue in the latest complaint, and Fairchild’s challenges to the validity of the patents were rejected during the course of the prior lawsuits as well.  Fairchild has not yet answered the complaint, and no trial date has been scheduled, but further proceedings are expected over the course of the coming months.

The Company is unable to predict the outcome of legal proceedings with certainty, and there can be no assurance that Power Integrations will prevail in the above-mentioned unsettled litigations. These litigations, whether or not determined in Power Integrations' favor or settled, will be costly and will divert the efforts and attention of the Company's management and technical personnel from normal business operations, potentially causing a material adverse effect on the business, financial condition and operating results. Currently, the Company is not able to estimate a loss or a range of loss for the ongoing litigation disclosed above, however adverse determinations in litigation could result in monetary losses, the loss of proprietary rights, subject the Company to significant liabilities, require Power Integrations to seek licenses from third parties or prevent the Company from licensing the technology, any of which could have a material adverse effect on the Company's business, financial condition and operating results.

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EARNINGS PER SHARE

9 Months Ended

Sep. 30, 2015

Earnings Per Share [Abstract]

EARNINGS PER SHARE

EARNINGS PER SHARE:

Basic earnings per share are calculated by dividing net income by the weighted-average shares of common stock outstanding during the period. Diluted earnings per share are calculated by dividing net income by the weighted-average shares of common stock and dilutive common equivalent shares outstanding during the period. Dilutive common equivalent shares included in this calculation consist of dilutive shares issuable upon the assumed exercise of outstanding common stock options, the assumed vesting of outstanding restricted stock units and both short- and long-term performance-based awards, and the assumed issuance of awards under the stock purchase plan, as computed using the treasury stock method.

A summary of the earnings per share calculation is as follows:        

	Three Months Ended				Nine Months Ended
	September 30,				September 30,
(In thousands, except per share amounts)	2015		2014		2015		2014
Basic earnings per share:
Net income	$	11,513	$	16,111	$	26,446	$	45,190
Weighted-average common shares	28,855		30,013		29,175		30,186
Basic earnings per share	$	0.40	$	0.54	$	0.91	$	1.50
Diluted earnings per share: (1)
Net income	$	11,513	$	16,111	$	26,446	$	45,190
Weighted-average common shares	28,855		30,013		29,175		30,186
Effect of dilutive awards:
Employee stock plans	443		744		681		867
Diluted weighted-average common shares	29,298		30,757		29,856		31,053
Diluted earnings per share	$	0.39	$	0.52	$	0.89	$	1.46

_______________ 

(1) The Company includes the shares underlying performance-based awards in the calculation of diluted earnings per share if the performance conditions have been satisfied as of the end of the reporting period and excludes such shares when the necessary conditions have not been met. The Company has excluded the shares underlying the 2015 and 2014 awards in the 2015 and 2014 calculations, respectively, as those shares were not contingently issuable as of the end of the period. 

In the three and nine months ended September 30, 2015, 69,000 and 8,000 outstanding stock awards were determined to be anti-dilutive, respectively, and therefore were excluded in the computation of diluted earnings per share. In the three and nine months ended September 30, 2014, no outstanding stock awards were determined to be anti-dilutive, and therefore no stock awards were excluded in the computation of diluted earnings per share.

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GOODWILL AND INTANGIBLE ASSETS

9 Months Ended

Sep. 30, 2015

Goodwill and Intangible Assets Disclosure [Abstract]

GOODWILL AND INTANGIBLE ASSETS

GOODWILL AND INTANGIBLE ASSETS:

Goodwill increased during the nine months ended September 30, 2015, due to the Company's acquisition of Cambridge Semiconductor Limited ("CamSemi") (refer to Note 10, Acquisitions, for details on the Company's CamSemi acquisition). Changes in the carrying amount of goodwill during the nine months ended September 30, 2015, are as follows:

(In thousands)	Goodwill
Balance at December 31, 2014	$	80,599
Goodwill acquired during the period	11,250
Ending balance at September 30, 2015	$	91,849

Intangible assets consist primarily of developed technology, acquired licenses, customer relationships, trade name, in-process research and development and patent rights, and are reported net of accumulated amortization. In January 2015, the Company acquired CamSemi, resulting in the addition of the following intangible assets: developed technology of $6.6 million, which will be amortized over a period of 3 - 7 years; and customer relationships of $2.4 million, which will be amortized over a period of 5 years. In August 2015, the Company purchased a building with existing third-party leases, resulting in the addition of in-place lease intangible assets of $0.7 million which will be amortized over a period of 2 years.

The Company amortizes the cost of all intangible assets over the shorter of the estimated useful life or the term of the developed technology, acquired licenses, customer relationships, trade name, patent rights and contractual lease period, which range from 2 to 12 years, with the exception of $1.3 million for the purchase of an internet domain name (the cost to acquire the domain name has been recorded as an intangible asset and will not be amortized as it has an indefinite useful life), and $4.7 million of in-process research and development. In-process research and development is assessed for impairment until the development is completed and products are available for sale, at which time the Company will begin to amortize the in-process research and development. The Company does not expect amortization of the capitalized in-process research and development to begin in 2015.

Amortization for acquired intangible assets was approximately $1.7 million and $5.2 million in the three and nine months ended September 30, 2015, respectively, and $1.3 million and $4.7 million, respectively, in the corresponding periods of the previous year. The Company does not believe there is any significant residual value associated with its finite-lived intangible assets:

	September 30, 2015							December 31, 2014
(In thousands)	Gross		Accumulated Amortization			Net		Gross		Accumulated Amortization			Net
Domain name	$	1,261	$	—		$	1,261	$	1,261	$	—		$	1,261
In-process research and development	4,690		—			4,690		4,690		—			4,690
Technology licenses	3,000		(2,850		)	150		3,000		(2,625		)	375
Patent rights	1,949		(1,949		)	—		1,949		(1,949		)	—
Developed technology	33,270		(10,708		)	22,562		26,670		(7,828		)	18,842
Customer relationships	20,030		(9,366		)	10,664		17,610		(7,254		)	10,356
Trade name	3,600		(3,600		)	—		3,600		(3,600		)	—
In-place leases	660		(30		)	630		—		—			—
Total intangible assets	$	68,460	$	(28,503	)	$	39,957	$	58,780	$	(23,256	)	$	35,524

The estimated future amortization expense related to finite-lived intangible assets at September 30, 2015, is as follows:

Fiscal Year	Estimated Amortization (in thousands)
2015 (remaining 3 months)	$	1,792
2016	6,663
2017	6,084
2018	5,152
2019	4,753
Thereafter	9,562
Total (1)	$	34,006

_______________

(1) The total above excludes $4.7 million of in-process research and development that will be amortized, upon completion of development, over the estimated useful life of the technology.

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SIGNIFICANT CUSTOMERS AND INTERNATIONAL SALES

9 Months Ended

Sep. 30, 2015

Risks and Uncertainties [Abstract]

SIGNIFICANT CUSTOMERS AND INTERNATIONAL SALES

SIGNIFICANT CUSTOMERS AND INTERNATIONAL SALES:

Segment Reporting

The Company is organized and operates as one reportable segment, the design, development, manufacture and marketing of integrated circuits and related components for use primarily in the high-voltage power-conversion market. The Company's chief operating decision maker, the Chief Executive Officer, reviews financial information presented on a consolidated basis for purposes of making operating decisions and assessing financial performance.

Customer Concentration

The Company's top ten customers accounted for approximately 64% and 61% of net revenues for the three and nine months ended September 30, 2015, respectively, and approximately 59% of net revenues in each of the corresponding periods of the previous year. A significant portion of these revenues are attributable to sales of the Company’s products to distributors of electronic components. These distributors sell the Company’s products to a broad, diverse range of end users, including OEMs and merchant power supply manufacturers.

One customer, a distributor of the Company's products, accounted for more than 10% of the Company's net revenues in the three and nine months ended September 30, 2015, and in the corresponding periods of 2014. A second customer, also a distributor, accounted for more than 10% of net revenues in the three month period ended September 30, 2015. The following table discloses these customers' percentage of revenues for the respective periods:    

	Three Months Ended				Nine Months Ended
	September 30,				September 30,
Customer	2015		2014		2015		2014
Avnet	20	%	19	%	21	%	20	%
Powertech Distribution Ltd.	11	%	*		*		*

_______________                        

* Total customer percentage of revenues was less than 10%.

No other customers accounted for 10% or more of the Company's net revenues in the periods presented.

Concentration of Credit Risk

Financial instruments that potentially subject the Company to concentrations of credit risk consist principally of cash investments and trade receivables. The Company has cash investment policies that limit cash investments to low-risk investments. With respect to trade receivables, the Company performs ongoing evaluations of its customers' financial conditions and requires letters of credit whenever deemed necessary. Additionally, the Company establishes an allowance for doubtful accounts based upon factors surrounding the credit risk of specific customers, historical trends related to past write-offs and other relevant information. Account balances are charged off against the allowance after all means of collection have been exhausted and the potential for recovery is considered remote. The Company does not have any off-balance-sheet credit exposure related to its customers. As of September 30, 2015, and December 31, 2014, 65% and 66%, respectively, of accounts receivable were concentrated with the Company's top 10 customers.

The following customers represented 10% or more of accounts receivable:

Customer	September 30, 2015		December 31, 2014
Avnet	23	%	22	%
ATM Electronic Corporation	12	%	*
Burnon International LTD.	*		11	%

_______________                        

* Total customer accounts receivable was less than 10%.

The above-mentioned customers are distributors of the Company’s products. No other customers accounted for 10% or more of the Company’s accounts receivable on these dates.

International Sales

The Company markets its products globally through its sales personnel and a worldwide network of independent sales representatives and distributors. As a percentage of total net revenues, international sales, which consist of sales to distributors and direct customers outside of the United States of America, comprise the following:     

	Three Months  Ended				Nine Months Ended
	September 30,				September 30,
	2015		2014		2015		2014
Hong Kong/China	49	%	47	%	49	%	46	%
Taiwan	15	%	16	%	14	%	16	%
Korea	10	%	11	%	10	%	11	%
Western Europe (excluding Germany)	11	%	11	%	11	%	11	%
Japan	4	%	5	%	5	%	5	%
Germany	3	%	2	%	3	%	2	%
Other	3	%	4	%	3	%	4	%
Total foreign revenue	95	%	96	%	95	%	95	%

The remainder of the Company’s sales is to customers within the United States of America.

Product Sales

Net revenues consist primarily of sales of the Company's high-voltage integrated-circuit products, insulated-gate bipolar transistor ("IGBT") drivers and high-voltage silicon diodes. When evaluating the Company's net revenues, the Company categorizes its sales into the following four end-market groupings: communications, computer, consumer and industrial. The table below provides the percentage of net sales activity by end market for the three and nine months ended September 30, 2015 and 2014:

	Three Months Ended				Nine Months Ended
	September 30,				September 30,
End Market	2015		2014		2015		2014
Communications	26	%	18	%	23	%	17	%
Computer	7	%	11	%	7	%	11	%
Consumer	36	%	36	%	37	%	37	%
Industrial	31	%	35	%	33	%	35	%

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PROVISION FOR INCOME TAXES

9 Months Ended

Sep. 30, 2015

Income Tax Disclosure [Abstract]

PROVISION FOR INCOME TAXES

PROVISION FOR INCOME TAXES:

Income-tax expense includes a provision for federal, state and foreign taxes based on the annual estimated effective tax rate applicable to the Company and its subsidiaries, adjusted for certain discrete items which are fully recognized in the period they occur.

The Company's effective tax rates for the three and nine months ended September 30, 2015, were 5.7% and 6.1%, respectively. The difference between the expected statutory rate of 35% and the Company's effective tax rates for the three and nine months ended September 30, 2015, was due primarily to the beneficial impact of the geographic distribution of the Company's world-wide earnings. The Company's effective tax rates for the three and nine months ended September 30, 2014, were 6.6% and (0.9)%, respectively. The difference between the expected statutory rate of 35% and the effective tax rates for the three and nine months ended September 30, 2014, was due primarily to the beneficial impact of the geographic distribution of the Company's world-wide earnings and additionally, for the nine months ended September 30, 2014, the Company's 2014 settlement with the IRS. The provision for income tax for the nine months ended September 30, 2014, includes, in the second quarter of 2014, a one-time benefit of $3.3 million comprising $2.8 million in federal income taxes and interest, and state income taxes of approximately $0.5 million. The one-time benefit includes the reversal of $4.1 million of related unrecognized tax benefits that had been recorded as non-current liabilities in the Company's consolidated balance sheets. The Company has now concluded all U.S. federal income-tax matters for the years through 2009.

The Company accounts for income taxes under the provisions of ASC 740. Under the provisions of ASC 740, deferred tax assets and liabilities are recognized based on the differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases, utilizing the tax rates that are expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled.

In assessing the realizability of deferred tax assets, management considers whether it is more likely than not that some portion or all of the deferred tax assets will not be realized. The ultimate realization of deferred tax assets is dependent upon the generation of future taxable income during the periods in which those temporary differences become deductible. Management considers the scheduled reversal of deferred tax liabilities and projected future taxable income. In the event that the Company determines, based on available evidence and management judgment, that all or part of the net deferred tax assets will not be realized in the future, the Company would record a valuation allowance in the period the determination is made. In addition, the calculation of tax liabilities involves significant judgment in estimating the impact of uncertainties in the application of complex tax laws. Resolution of these uncertainties in a manner inconsistent with the Company's expectations could have a material impact on its results of operations and financial position.

As of September 30, 2015, the Company maintains a valuation allowance on its California deferred tax assets, New Jersey deferred tax assets, capital losses for federal purposes and a valuation allowance with respect to its deferred tax assets relating to tax credits in Canada.

To ensure an additional source of U.S. cash, the Company plans to repatriate a portion of its current year offshore earnings to the U.S. for domestic operations and accordingly has provided for estimated federal and state income taxes on such portion of its current year offshore earnings. If circumstances change and it becomes apparent that some or all of the undistributed earnings of the Company's offshore subsidiary will be remitted in the foreseeable future but income taxes have not been recognized, the Company will accrue income taxes attributable to such undistributed earnings.

Determining the consolidated provision for (benefit from) income tax expense, income tax liabilities and deferred tax assets and liabilities involves judgment. The Company calculates and provides for income taxes in each of the tax jurisdictions in which it operates, which involves estimating current tax exposures as well as making judgments regarding the recoverability of deferred tax assets in each jurisdiction. The estimates used could differ from actual results, which may have a significant impact on operating results in future periods.

On July 27, 2015, in Altera Corp. v. Commissioner, the U.S. Tax Court issued an opinion related to the treatment of stock-based compensation expense in an intercompany cost-sharing arrangement. A final decision has yet to be issued by the Tax Court due to other outstanding issues related to the case. At this time, the U.S. Department of the Treasury has not withdrawn the requirement to include stock-based compensation expense from IRS cost-sharing regulations. The Company has reviewed this case and its impact and concluded that no adjustment to the consolidated financial statements is appropriate at this time. The Company will continue to monitor ongoing developments and potential impacts to the consolidated financial statements.

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SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Components of the Balance Sheet) (Details) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Accounts Receivable, Net [Abstract]
Accounts receivable trade	$ 46,816	$ 38,344
Accrued ship and debit and rebate claims	35,436	27,967
Allowance for doubtful accounts	319	191
Total	11,061	10,186
Prepaid Expense, Current [Abstract]
Prepaid legal fees	23	1,506
Loan to Cambridge Semiconductor (Note 10)	0	6,600
Prepaid income tax	1,386	3,208
Prepaid maintenance agreements	866	1,023
Interest receivable	371	664
VAT receivable	525	987
Supplier prepayment	366	800
Other	2,243	1,591
Total	$ 5,780	$ 16,379

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ACQUISITIONS (Text Disclosures) (Details) - USD ($) $ in Thousands		3 Months Ended	9 Months Ended
	Jan. 02, 2015	Dec. 31, 2014	Sep. 30, 2015	Aug. 31, 2015
Business Acquisition [Line Items]
Notes, Loans and Financing Receivable, Net, Current		$ 6,600	$ 0
Business Acquisition, Percentage of Voting Interests Acquired	100.00%
Minimum [Member]
Business Acquisition [Line Items]
Finite-Lived Intangible Asset, Useful Life			2 years
Maximum [Member]
Business Acquisition [Line Items]
Finite-Lived Intangible Asset, Useful Life			12 years
Cambridge Semiconductor Limited [Member]
Business Acquisition [Line Items]
Payments to Acquire Businesses, Gross			$ 16,700
Consideration applied against outstanding loan	$ 6,600
Acquisition related costs		800	200
Business Combination, Consideration Transferred			$ 23,300
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles	9,020
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities	(2,922)
Cambridge Semiconductor Limited [Member] | Developed technology [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles	$ 6,600
Cambridge Semiconductor Limited [Member] | Developed technology [Member] | Minimum [Member]
Business Acquisition [Line Items]
Finite-Lived Intangible Asset, Useful Life			3 years
Cambridge Semiconductor Limited [Member] | Developed technology [Member] | Maximum [Member]
Business Acquisition [Line Items]
Finite-Lived Intangible Asset, Useful Life			7 years
Cambridge Semiconductor Limited [Member] | Customer relationships [Member]
Business Acquisition [Line Items]
Finite-Lived Intangible Asset, Useful Life			5 years
Finite-Lived Intangible Asset, Reacquisition of Customer Relationship Term	2 years
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles	$ 2,420
Building [Member]
Business Acquisition [Line Items]
Payments to Acquire Businesses, Gross			$ 10,400
Finite-Lived Intangible Asset, Useful Life			2 years
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Land				$ 3,500
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Buildings				6,300
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles				700
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities				$ (100)
Property, Plant and Equipment, Useful Life			30 years
Cambridge Semiconductor Limited [Member]
Business Acquisition [Line Items]
Notes, Loans and Financing Receivable, Net, Current		$ 6,600

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BANK LINE OF CREDIT

9 Months Ended

Sep. 30, 2015

Debt Disclosure [Abstract]

BANK LINE OF CREDIT

BANK LINE OF CREDIT:

On July 5, 2012, the Company entered into a Credit Agreement (the "Credit Agreement") with two banks. The Credit Agreement provides the Company with a $100.0 million revolving line of credit to use for general corporate purposes with a $20.0 million sublimit for the issuance of standby and trade letters of credit. The Credit Agreement was amended on April 1, 2014, to extend the Credit Agreement termination date from July 5, 2015, to April 1, 2017, with all other terms of the Credit Agreement remaining the same. The Company's ability to borrow under the revolving line of credit is conditioned upon the Company's compliance with specified covenants, including reporting and financial covenants, primarily a minimum cash requirement and a debt to earnings ratio, with which the Company is currently in compliance. All advances under the revolving line of credit will become due on April 1, 2017, or earlier in the event of a default. As of September 30, 2015, the Company had no letters of credit outstanding and no amount outstanding under the credit agreement.

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FAIR VALUE MEASUREMENTS (Tables)

9 Months Ended

Sep. 30, 2015

Fair Value Disclosures [Abstract]

Fair value of marketable securities and investments

The fair-value hierarchy of the Company's marketable securities at September 30, 2015, and December 31, 2014, was as follows:

	Fair Value Measurement at
	September 30, 2015
(In thousands)	Total Fair Value		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)
Commercial paper	$	18,019	$	—	$	18,019
Money market funds	11,742		11,742		—
Corporate securities	78,777		—		78,777
Total	$	108,538	$	11,742	$	96,796

	Fair Value Measurement at
	December 31, 2014
(In thousands)	Total Fair Value		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)
Money market funds	$	3,370	$	3,370	$	—
Corporate securities	114,575		—		114,575
Total	$	117,945	$	3,370	$	114,575

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EARNINGS PER SHARE (Details) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Basic earnings per share:
NET INCOME		$ 11,513	$ 16,111	$ 26,446	$ 45,190
Weighted-average common shares		28,855,000	30,013,000	29,175,000	30,186,000
Basic earnings per share		$ 0.40	$ 0.54	$ 0.91	$ 1.50
Diluted earnings per share:
NET INCOME		$ 11,513	$ 16,111	$ 26,446	$ 45,190
Weighted-average common shares		28,855,000	30,013,000	29,175,000	30,186,000
Effect of dilutive awards:
Employee stock plans		443,000	744,000	681,000	867,000
Diluted weighted-average common shares		29,298,000	30,757,000	29,856,000	31,053,000
Diluted earnings per share	[1]	$ 0.39	$ 0.52	$ 0.89	$ 1.46
Stock awards excluded in the computation of diluted earnings per share		69,000	0	8,000	0

[1] The Company includes the shares underlying performance-based awards in the calculation of diluted earnings per share if the performance conditions have been satisfied as of the end of the reporting period and excludes such shares when the necessary conditions have not been met. The Company has excluded the shares underlying the 2015 and 2014 awards in the 2015 and 2014 calculations, respectively, as those shares were not contingently issuable as of the end of the period.

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FAIR VALUE MEASUREMENTS (Details) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total	$ 108,538	$ 117,945
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total	11,742	3,370
Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total	96,796	114,575
Commercial paper [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and Cash Equivalents	18,019
Commercial paper [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and Cash Equivalents	0
Commercial paper [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and Cash Equivalents	18,019
Money market funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and Cash Equivalents	11,742	3,370
Money market funds [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and Cash Equivalents	11,742	3,370
Money market funds [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and Cash Equivalents	0	0
Corporate securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Corporate securities	78,777	114,575
Corporate securities [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Corporate securities	0	0
Corporate securities [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Corporate securities	$ 78,777	$ 114,575

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CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Statement of Comprehensive Income [Abstract]
NET INCOME	$ 11,513	$ 16,111	$ 26,446	$ 45,190
Other comprehensive income, net of tax:
Foreign currency translation adjustments, net of $0 tax in the three and nine months ended September 30, 2015 and 2014 (Note 2)	40	(53)	18	(42)
Unrealized gain (loss) on marketable securities, net of $0 tax in the three and nine months ended September 30, 2015 and 2014 (Note 2)	20	(246)	(17)	(7)
Amortization of defined benefit pension items, net of tax of $18 and $26 in the three and nine months ended September 30, 2015, respectively and $4 and $12 in the three and nine months ended September 30, 2014, respectively (Note 2)	64	15	92	45
Total other comprehensive income (loss)	124	(284)	93	(4)
TOTAL COMPREHENSIVE INCOME	$ 11,637	$ 15,827	$ 26,539	$ 45,186

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STOCK PLANS AND SHARE-BASED COMPENSATION

9 Months Ended

Sep. 30, 2015

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

STOCK PLANS AND SHARE-BASED COMPENSATION

STOCK PLANS AND SHARE-BASED COMPENSATION:

Stock Plans

As of September 30, 2015, the Company had two stock-based compensation plans (the “Plans”) which are described below.

2007 Equity Incentive Plan

The 2007 Equity Incentive Plan (the "2007 Plan") was adopted by the board of directors on September 10, 2007, and approved by the stockholders on November 7, 2007, as an amendment and restatement of the 1997 Stock Option Plan (the "1997 Plan"). The 2007 Plan provides for the grant of incentive stock options, non-statutory stock options, restricted stock awards, restricted stock unit ("RSU") awards, stock appreciation rights, performance-based ("PSU") awards , long-term performance based ("PRSU") awards and other stock awards to employees, directors and consultants. As of September 30, 2015, the maximum remaining number of shares that may be issued under the 2007 Plan was 6,377,504 shares, which includes options granted but not exercised and awards granted but unvested and shares remaining available for issuance under the 1997 Plan, including shares subject to outstanding options and stock awards under the 1997 Plan. Pursuant to the 2007 Plan, the exercise price for incentive stock options and non-statutory stock options is generally at least 100% of the fair market value of the underlying shares on the date of grant. Options generally vest over 48 months measured from the date of grant. Options generally expire no later than ten years after the date of grant, subject to earlier termination upon an optionee's cessation of employment or service.  

Beginning January 27, 2009, grants pursuant to the Directors Equity Compensation Program (which was adopted by the board of directors on January 27, 2009) to non-employee directors have been made primarily under the 2007 Plan. The Directors Equity Compensation Program provides for grants to outside directors as follows: effective annually, upon the first trading day of July, each outside director receives a grant of an equity award with an aggregate value of $100,000, which will become exercisable or vest immediately prior to the Company's next annual meeting of stockholders, subject to the director's continued service. At each outside director's election, such award may consist entirely of RSUs or entirely of stock options. The quantity of options would be calculated by dividing $100,000 by the Black-Scholes value on the date of grant. The quantity of RSUs issued would be calculated by dividing $100,000 by the grant-date fair value. Further, on the date of election of a new outside director, such new director would receive such grant as continuing outside directors receive on the first trading day of July; provided, however, that such grant is prorated for the portion of the year that such new outside director will serve until the next first trading day of July. The Directors Equity Compensation Program will remain in effect at the discretion of the board of directors or the compensation committee of the board.

On July 28, 2009, the 2007 Plan was amended generally to prohibit outstanding options or stock appreciation rights from being canceled in exchange for cash without stockholder approval.

1997 Employee Stock Purchase Plan

Under the 1997 Employee Stock Purchase Plan (the “Purchase Plan”), eligible employees may apply accumulated payroll deductions, which may not exceed 15% of an employee's compensation, to the purchase of shares of the Company's common stock at periodic intervals. The purchase price of stock under the Purchase Plan is equal to 85% of the lower of (i) the fair market value of the Company's common stock on the first day of each offering period, or (ii) the fair market value of the Company's common stock on the purchase date (as defined in the Purchase Plan). Each offering period consists of one purchase period of approximately six months' duration. An aggregate of 3,000,000 shares of common stock were reserved for issuance to employees under the Purchase Plan. As of September 30, 2015, 2,808,265 shares had been purchased and 191,735 shares were reserved for future issuance under the Purchase Plan.

Stock-Based Compensation

The Company applies the provisions of ASC 718-10. Under the provisions of ASC 718-10, the Company recognizes the fair value of stock-based compensation in financial statements over the requisite service period of the individual grants, which generally equals a four year vesting period. The Company uses estimates of volatility, expected term, risk-free interest rate, dividend yield and forfeitures in determining the fair value of these awards and the amount of compensation expense to recognize. The Company uses the straight-line method to amortize all stock awards granted over the requisite service period of the award, and uses historical data to estimate pre-vesting forfeitures, recognizing expense only for those awards that are expected to vest.

Determining Fair Value of Stock Options

The Company uses the Black-Scholes valuation model for valuing stock option grants using the following assumptions and estimates:

ExpectedVolatility. The Company calculates expected volatility based on the historical price volatility of the Company's stock.

Expected Term. The Company utilizes a model which uses historical exercise, cancellation and outstanding option data to calculate the expected term of stock option grants.

Risk-Free Interest Rate. The Company bases the risk-free interest rate used in the Black-Scholes valuation model on the implied yield available on a U.S. Treasury note with a term approximately equal to the expected term of the underlying grants.

Dividend Yield. The dividend yield was calculated by dividing the annual dividend by the average closing price of the Company's common stock on a quarterly basis.

The following table summarizes the stock-based compensation expense recognized in accordance with ASC 718-10 for the three and nine months ended September 30, 2015, and September 30, 2014:

	Three Months Ended				Nine Months Ended
	September 30,				September 30,
(In thousands)	2015		2014		2015		2014
Cost of revenues	$	219	$	131	$	725	$	648
Research and development	1,277		971		3,974		3,522
Sales and marketing	877		779		2,767		2,578
General and administrative	988		699		4,036		3,922
Total stock-based compensation expense	$	3,361	$	2,580	$	11,502	$	10,670

Stock-based compensation expense in the three months ended September 30, 2015 was $3.4 million (comprising approximately $0.1 million related to stock options, a reduction to expense of $0.2 million related to PSUs and PRSUs, $3.2 million related to RSUs and $0.3 million related to the Purchase Plan). In the nine months ended September 30, 2015, stock compensation expense was $11.5 million (comprising approximately $0.5 million related to stock options, $0.6 million related to PSUs and PRSUs, $9.5 million related to RSUs and $0.9 million related to the Purchase Plan).

Stock-based compensation expense in the three months ended September 30, 2014, was $2.6 million (comprising approximately $0.2 million related to stock options, a reduction to expense of $0.8 million related to PSUs and PRSUs, $2.8 million related to RSUs and $0.4 million related to the Purchase Plan). In the nine months ended September 30, 2014, stock compensation expense was $10.7 million (comprising approximately $1.0 million related to stock options, $0.4 million related to PSUs and PRSUs, $8.4 million related to RSUs and $0.9 million related to the Purchase Plan).

The following table summarizes total compensation expense related to unvested awards not yet recognized, net of expected forfeitures, and the weighted-average period over which it is expected to be recognized as of September 30, 2015:

	September 30, 2015
	Unrecognized Compensation Expense for Unvested Awards (in thousands)		Weighted Average Remaining Recognition Period (in years)
Options	$	296	0.57
Performance-based awards	189		0.25
Long-term performance-based awards	606		1.81
Restricted stock unit awards	24,049		2.46
Purchase plan	434		0.34
Total unrecognized compensation expense	$	25,574

The fair value of employees’ stock purchase rights under the Purchase Plan was estimated using the Black-Scholes model with the following weighted-average assumptions:        

	Three Months Ended		Nine Months Ended
	September 30,		September 30,
	2015	2014	2015	2014
Risk-free interest rate	0.17%	0.05%	0.13%	0.05	%	-	0.07%
Expected volatility rate	26%	48%	29%	30	%	-	48%
Expected dividend yield	1.20%	0.85%	1.08%	0.66	%	-	0.85%
Expected term of purchase right (in years)	0.5	0.5	0.5	0.5
Weighted-average estimated fair value of purchase rights	$8.41	$15.25	$10.18	$14.40

The Company did not grant stock options in the three and nine months ended September 30, 2015, or September 30, 2014, and therefore no fair-value assumptions are reported.    

A summary of stock option activity under the Plans, excluding PSUs, PRSUs and RSUs, as of September 30, 2015, and changes during the nine months then ended, is presented below:

	Shares (in thousands)		Weighted- Average Exercise Price	Weighted-Average Remaining Contractual Term (in years)	Aggregate Intrinsic Value (in thousands)
Outstanding at January 1, 2015	1,344		$27.27
Granted	—		—
Exercised	(96	)	$25.29
Forfeited or expired	(2	)	$37.97
Outstanding at September 30, 2015	1,246		$27.39	2.91	$	18,463
Exercisable at September 30, 2015	1,228		$27.17	2.86	$	18,463
Vested and expected to vest at September 30, 2015	1,246		$27.39	2.91	$	18,463

The Company did not grant stock options in the three and nine months ended September 30, 2015, and September 30, 2014. Beginning in 2010 the Company's equity grants to new hires and its annual incentive grants to non-executive employees have been primarily in the form of RSU's. The total intrinsic value of options exercised during the three and nine months ended September 30, 2015, was approximately $0.3 million and $2.4 million, respectively, and the total intrinsic value of options exercised during the three and nine months ended September 30, 2014, was approximately $1.8 million and $8.7 million, respectively.

PSU Awards

Under the PSU awards program, the Company grants awards in an amount equal to twice the target number of shares to be issued if the annual target performance metrics are met. The number of shares that are released at the end of the performance year can range from zero to 200% of the targeted number depending on the Company's performance. In 2015, the performance metrics of this program are annual targets consisting of net revenue, non-GAAP operating income and strategic goals. Each PSU granted from the 2007 Plan will reduce the number of shares available for issuance under the 2007 Plan by two shares.

During the nine months ended September 30, 2015, the Company granted approximately 88,000 annual PSUs to the Company's employees and executives. As the net revenue, non-GAAP operating earnings and strategic goals are considered performance conditions, expenses associated with these awards, net of estimated forfeitures, are recorded throughout the year depending on the number of shares expected to vest based on progress toward the performance targets. The fair value of PSUs is determined using the fair value of the Company's common stock on the grant date, reduced by the discounted present value of dividends expected to be declared before the awards vest. If the performance conditions are not achieved, no compensation cost is recognized and any previously recognized compensation is reversed.

In January 2015, it was determined that the Company had not reached the minimum level of the established 2014 performance targets (consisting of revenue and non-GAAP operating income). Accordingly, no shares subject to PSUs granted in connection with the 2014 performance based incentive plan were released to the Company's employees and executives in 2015.

A summary of PSUs outstanding as of September 30, 2015, and activity during the nine months then ended, is presented below:

	Shares (in thousands)		Weighted- Average Grant Date Fair Value Per Share	Weighted-Average Remaining Contractual Term (in years)	Aggregate Intrinsic Value (in thousands)
Outstanding at January 1, 2015	—		—
Granted	88		$52.39
Vested	—		—
Change in units due to performance achievement for PSUs vested in the year	—		—
Forfeited or expired	(1	)	$50.79
Outstanding at September 30, 2015	87		$52.41	0.25	$	3,684
Outstanding and expected to vest at September 30, 2015	12			0.25	$	516

The weighted-average grant-date fair value per share of PSUs granted in the three and nine months ended September 30, 2015 was approximately $37.81 and $52.39, respectively, and $53.93 in the nine months ended September 30, 2014 (there were no PSUs granted in the three months ended September 30, 2014). There were no awards released in the three and nine months ended September 30, 2015. The grant-date fair value of awards released, which were fully vested, in the nine months ended September 30, 2014, was approximately $3.2 million. No awards were released in the three months ended September 30, 2014.

PRSU Awards

      In the first quarter of 2014 the Company began granting PRSU awards. The Company's PRSU program provides for the issuance of PRSUs which will vest based on the Company's performance measured against the PRSU Plan's established revenue targets. The PRSUs were granted in an amount equal to twice the target number of shares to be issued if the target performance metrics are met. The actual number of shares the recipient receives is determined at the end of a three-year performance period based on results achieved versus the Company's performance goals, and may range from zero to 200% of the target number. The performance goals for PRSUs granted in fiscal 2014 and 2015 were based on the Company's annual revenue growth. Each PRSU granted from the 2007 Plan will reduce the number of shares available for issuance under the 2007 Plan by two shares.

            Recipients of a PRSU generally must remain employed by the Company on a continuous basis through the end of the applicable three-year performance period in order to receive shares subject to that award. Expenses associated with these awards, net of estimated forfeitures, are recorded throughout the year depending on the number of shares expected to vest based on progress toward the performance target. The fair value of PRSU awards is determined using the fair value of the Company's common stock on the grant date, reduced by the discounted present value of dividends expected to be declared before the awards vest. If the performance conditions are not achieved, no compensation cost is recognized and any previously recognized compensation is reversed.

A summary of PRSUs outstanding as of September 30, 2015, and activity during the nine months then ended, is presented below:

	Shares (in thousands)		Weighted- Average Grant Date Fair Value Per Share	Weighted-Average Remaining Contractual Term (in years)	Aggregate Intrinsic Value (in thousands)
Outstanding at January 1, 2015	61		$55.51
Granted	72		$52.47
Vested	—		—
Forfeited or expired	(4	)	$57.76
Outstanding at September 30, 2015	129		$53.75	1.81	$	5,427
Outstanding and expected to vest at September 30, 2015	17			1.79	$	724

The weighted-average grant-date fair value per share of PRSUs granted in the nine months ended September 30, 2015 and September 30, 2014, was approximately $52.47 and $56.15, respectively (there were no PRSUs granted in the three months ended September 30, 2015, or September 30, 2014).

RSU Awards

The Company grants RSUs to employees under the 2007 Plan. RSUs granted to employees typically vest ratably over a four year period, and are converted into shares of the Company's common stock upon vesting on a one-for-one basis subject to the employee's continued service with the Company over that period. The fair value of RSUs is determined using the fair value of the Company's common stock on the date of the grant, reduced by the discounted present value of dividends expected to be declared before the awards vest. Compensation expense is recognized on a straight-line basis over the requisite service period of each grant adjusted for estimated forfeitures. Each RSU award granted from the 2007 plan will reduce the number of shares available for issuance under the 2007 Plan by two shares.

A summary of RSUs outstanding as of September 30, 2015, and changes during the nine months then ended, are as follows:

	Shares (in thousands)		Weighted- Average Grant Date Fair Value Per Share	Weighted-Average Remaining Contractual Term (in years)	Aggregate Intrinsic Value (in thousands)
Outstanding at January 1, 2015	692		$43.86
Granted	302		$49.90
Vested	(257	)	$42.49
Forfeited or expired	(48	)	$45.55
Outstanding at September 30, 2015	689		$46.90	1.46	$	29,073
Outstanding and expected to vest at September 30, 2015	636			1.40	$	26,804

The weighted-average grant-date fair value per share of RSUs awarded in the three and nine months ended September 30, 2015, was approximately $42.65 and $49.90, respectively, and $58.03 and $51.30, respectively, in the corresponding periods of the previous year. The grant-date fair value of RSUs vested in the three and nine months ended September 30, 2015, was approximately $0.4 million and $10.9 million, respectively, and $0.5 million and $10.0 million, respectively, in the corresponding periods of the previous year.

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INVENTORIES (Tables)

9 Months Ended

Sep. 30, 2015

Inventory Disclosure [Abstract]

Inventories

Inventories consist of the following:

(In thousands)	September 30, 2015		December 31, 2014
Raw materials	$	18,661	$	21,127
Work-in-process	14,659		14,643
Finished goods	22,119		28,255
Total	$	55,439	$	64,025

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STOCK PLANS AND SHARE-BASED COMPENSATION (Fair Value Assumptions) (Details) - Employee Stock [Member] - $ / shares	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rate	0.17%	0.05%	0.13%
Risk-Free Interest Rate, Minimum				0.05%
Risk-Free Interest Rate, Maximum				0.07%
Expected volatility rate	26.00%	48.00%	29.00%
Expected Volatility Rate, Minimum				30.00%
Expected Volatility Rate, Maximum				48.00%
Expected dividend yield	1.20%	0.85%	1.08%
Expected Dividend Yield, Minimum				0.66%
Expected Dividend Yield, Maximum				0.85%
Expected term of purchase right (in years)	6 months	6 months	6 months	6 months
Weighted-average estimated fair value of purchase rights	$ 8.41	$ 15.25	$ 10.18	$ 14.40

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RECENT ACCOUNTING PRONOUNCEMENTS

9 Months Ended

Sep. 30, 2015

New Accounting Pronouncements and Changes in Accounting Principles [Abstract]

RECENT ACCOUNTING PRONOUNCEMENTS

RECENT ACCOUNTING PRONOUNCEMENTS:

In May 2014, the Financial Accounting Standards Board ("FASB") amended the existing accounting standards for revenue recognition, Accounting Standards Update ("ASU") 2014-09, Revenue from Contracts with Customers. The amendments are based on the principle that revenue should be recognized to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. The Company is required to adopt the amendments in the first quarter of 2018. Early adoption is permitted; however, the Company is not permitted to adopt the standard earlier than January 1, 2017. The amendments may be applied retrospectively to each prior period presented or retrospectively with the cumulative effect recognized as of the date of initial application. The Company is currently evaluating the impact of these amendments and the transition alternatives on its consolidated financial statements.