Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Oct. 04, 2015	Sep. 28, 2014
Cash flows from operating activities:
Net income	$ 168,328	$ 94,854
Adjustments to reconcile net income to net cash provided by operating activities:
Gain on sale of discontinued business	(78,290)	0
Stock-based compensation expense	15,964	11,258
Depreciation of property, plant, and equipment	7,223	6,194
Amortization of intangible assets	3,203	2,934
Amortization of discounts or premiums on investments	536	1,596
Realized gain on sale of investments	(240)	(651)
Tax effect of stock option exercises	(9,937)	(7,178)
Change in deferred income taxes	(2,134)	(2,959)
Accounts receivable	(31,380)	(51,961)
Inventories	(11,363)	(6,555)
Accounts payable	(6,823)	4,133
Accrued expenses	(4,010)	6,221
Accrued income taxes	18,032	7,331
Deferred revenue	6,035	9,453
Other	(1,086)	(11,683)
Net cash provided by operating activities	74,058	62,987
Cash flows from investing activities:
Purchases of investments	(547,553)	(283,982)
Maturities and sales of investments	521,464	239,396
Purchases of property, plant, and equipment	(13,017)	(9,078)
Cash paid for acquisition of business	(1,023)	0
Cash paid for purchased technology	(10,475)	0
Net proceeds from sale of discontinued business	104,496	0
Net cash provided by (used in) investing activities	53,892	(53,664)
Cash flows from financing activities:
Issuance of common stock under stock plans	27,440	15,651
Repurchase of common stock	(126,351)	(35,140)
Payment of dividends	(12,137)	0
Tax effect of stock option exercises	9,937	7,178
Net cash used in financing activities	(101,111)	(12,311)
Effect of foreign exchange rate changes on cash and cash equivalents	(2,970)	523
Net change in cash and cash equivalents	23,869	(2,465)
Cash and cash equivalents at beginning of period	55,694	40,644
Cash and cash equivalents at end of period	79,563	38,179
Non-cash items related to discontinued operations:
Depreciation and amortization expense	566	866
Capital expenditures	482	467
Stock-based compensation expense	$ 1,533	$ 786