CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands	12 Months Ended
	Mar. 31, 2011	Mar. 31, 2010	Mar. 31, 2009
CASH FLOWS FROM OPERATING ACTIVITIES
Net income (loss)	$ 109,243	$ 57,378	$ (64,899)
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation and amortization	16,275	18,144	25,822
Stock-based Compensation	15,873	14,577	15,742
Provision for (benefit from) doubtful accounts and sales allowances	(8)	(243)	2,698
Provision for excess and obsolete inventories	1,099	418	11,364
Benefit from deferred income taxes	(5,165)	(12,449)	(26,853)
Income tax benefit associated with stock option exercises	6,195	3,669	1,025
Excess tax benefit from stock-based compensation	5,747	2,247	592
Amortization of premium (accretion of purchase discounts) on investments, net	578	0	0
Impairment of goodwill and long-lived assets	0	25,194	117,464
Non-cash restructuring charges	0	6,261	581
Loss on sale of discontinued operations	0	611	0
Other operating activities	(5)	384	358
Changes in assets and liabilities:
Accounts receivable, net	(15,086)	388	50,706
Inventory, net	12,962	27,620	(5,358)
Current and other assets	(2,280)	2,868	(6,935)
Accounts payable	10,216	(9,048)	(15,069)
Accrued liabilities	9,873	(1,001)	(6,701)
Income taxes	4,209	11,205	(203)
Cash provided by operating activities	158,232	143,729	99,150
CASH FLOWS FROM INVESTING ACTIVITIES
Proceeds from sales of short-term investments	28,034	4,000	0
Proceeds from maturities of short-term investments	114,495	145,000	30,000
Purchase of short-term investments	(256,258)	(84,990)	(89,896)
Proceeds from sales of long-term investments	664	750	0
Purchase of long-term investments	(48,870)	0	0
Capital expenditures and other assets	(18,567)	(6,262)	(23,682)
Proceeds from sale of property, plant and equipment and assets held for sale	9,066	277	0
Proceeds received from sale of AEG segment	1,625	9,121	0
Other investing activities	(100)	0	406
Cash provided by (used for) investing activities	(169,911)	67,896	(83,172)
CASH FLOWS FROM FINANCING ACTIVITIES
Repurchase of common stock including taxes paid related to net share settlement on equity awards	(105,716)	(49,652)	(17,817)
Proceeds from sale of treasury stock	4,192	3,623	5,198
Proceeds from issuance of common stock	50,109	32,581	6,899
Payment of cash dividends	(9,703)	(9,781)	(9,787)
Excess tax benefit from stock-based compensation	5,747	2,247	592
Cash used for financing activities	(55,371)	(20,982)	(14,915)
Effect of exchange rate changes on cash and cash equivalents	1,464	1,125	(5,961)
Net increase (decrease) in cash and cash equivalents	(65,586)	191,768	(4,898)
Cash and cash equivalents at beginning of year	349,961	158,193	163,091
Cash and cash equivalents at end of year	284,375	349,961	158,193
SUPPLEMENTAL DISCLOSURES
Cash paid for income taxes	$ 29,180	$ 11,663	$ 12,519