Condensed Consolidated Statements Of Cash Flows (USD $) In Thousands	6 Months Ended
	Sep. 30, 2011		Sep. 30, 2010
Operating activities:
Net (loss) income	$ (8,029)		$ 4,966
Adjustments to reconcile net (loss) income to net cash (used for) provided by operating activities:
Depreciation	3,840		3,639
Amortization of purchased intangibles	4,096		7,432
Stock-based compensation expense:
Stock options	2,579		2,076
Restricted stock units	4,723		5,745
Contingent consideration adjustment	(2,267)
Capitalization of mask set cost			(1,177)
Net gain (loss) on disposals of property	10		(320)
Changes in operating assets and liabilities:
Accounts receivable	(8,086)		850
Inventories	7,834		(2,170)
Other assets	(7,159)		(1,515)
Accounts payable	(5,908)		321
Accrued payroll and other accrued liabilities	55		2,503
Deferred revenue	(560)		186
Net cash (used for) provided by operating activities	(8,872)		22,536
Investing activities:
Purchases of short-term investments	(67,735)		(90,012)
Proceeds from sales and maturities of short-term investments	87,746		36,132
Purchase of property and equipment	(9,757)		(5,987)
Proceeds from sale of property and equipment			345
Purchases of strategic equity investment	(2,500)
Proceeds from the sale of strategic equity investment			4,991
Funding of note receivable	(1,000)
Purchase of a business, net of cash acquired			(31,484)
Net cash provided by (used for) investing activities	6,754		(86,015)
Financing activities:
Proceeds from issuance of common stock	2,952		4,036
Funding of restricted stock units withheld for taxes	(2,441)		(2,361)
Repurchase of common stock	(20,852)		(23,112)
Funding of structured stock repurchase agreements	(10,000)		(10,000)
Funds received from structured stock repurchase agreements, including gains			15,512
Other	(160)		(356)
Net cash used for financing activities	(30,501)		(16,281)
Net decrease in cash and cash equivalents	(32,619)		(79,760)
Cash and cash equivalents at beginning of year	84,402	[1]	122,526
Cash and cash equivalents at end of year	51,783		42,766
Supplementary cash flow disclosures:
Cash paid for income taxes	$ 22		$ 142

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