Condensed Consolidated Statements Of Cash Flows (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Dec. 31, 2011		Dec. 31, 2010
Operating activities:
Net (loss) income	$ (15,106)		$ 3,005
Adjustments to reconcile net (loss) income to net cash (used for) provided by operating activities:
Depreciation	6,000		5,433
Amortization of purchased intangibles	5,425		12,188
Stock-based compensation expense:
Stock options	4,207		4,049
Restricted stock units	7,528		8,861
Contingent consideration adjustment	(2,267)
Capitalization of mask set cost			(1,177)
Net loss (gain) on disposals of property	10		(323)
Changes in operating assets and liabilities:
Accounts receivable	(10,831)		9,196
Inventories	8,992		(6,936)
Other assets	(3,825)		(3,750)
Accounts payable	(5,124)		(510)
Accrued payroll and other accrued liabilities	2,506		4,046
Deferred tax liability			656
Deferred revenue	(465)		1,140
Net cash (used for) provided by operating activities	(2,950)		35,878
Investing activities:
Purchases of short-term investments	(79,891)		(100,407)
Proceeds from sales and maturities of short-term investments	95,308		78,627
Purchase of property and equipment	(11,899)		(8,978)
Proceeds from sale of property and equipment			365
Purchases of strategic equity investments	(4,750)
Proceeds from sale of strategic equity investment			4,991
Purchase of a business, net of cash acquired			(31,484)
Net cash used for investing activities	(1,232)		(56,886)
Financing activities:
Proceeds from issuance of common stock	3,874		4,321
Funding of restricted stock units withheld for taxes	(2,739)		(2,518)
Repurchase of common stock	(20,852)		(23,310)
Funding of structured stock repurchase agreements	(10,000)		(10,000)
Funds received from structured stock repurchase agreements, including gains			15,512
Other	(272)		(329)
Net cash used for financing activities	(29,989)		(16,324)
Net decrease in cash and cash equivalents	(34,171)		(37,332)
Cash and cash equivalents at beginning of period	84,402	[1]	122,526
Cash and cash equivalents at end of period	50,231		85,194
Supplementary cash flow disclosures:
Cash paid for income taxes	$ 627		$ 112

[1] Note: Amounts have been derived from the March 31, 2011 audited consolidated financial statements.