CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Dec. 31, 2011	Dec. 31, 2010
CASH FLOWS FROM OPERATING ACTIVITIES
Net income	$ 85,150	$ 82,927
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	10,328	11,329
Stock-based compensation	13,267	11,965
Provision for excess and obsolete inventories	2,337	664
Benefit from deferred income taxes	(7,924)	(4,348)
Income tax benefit associated with stock option exercises	4,169	5,329
Excess tax benefit from stock-based compensation	(5,147)	(4,900)
Amortization of premium on investments, net	1,228	328
Other operating activities	627	(31)
Changes in assets and liabilities:
Accounts receivable, net	(6,378)	(22,720)
Inventory, net	(3,599)	5,780
Current and other assets	1,093	(184)
Accounts payable	(12,345)	(1,563)
Accrued liabilities	(7,235)	4,310
Income taxes	11,900	(2,417)
Cash provided by operating activities	87,471	86,469
CASH FLOWS FROM INVESTING ACTIVITIES
Proceeds from sales of short-term investments	68,539	23,250
Proceeds from maturities of short-term investments	126,231	7,495
Purchase of short-term investments	(122,480)	(159,882)
Proceeds from sales of long-term investments	4,936	0
Purchase of long-term investments	(68,313)	(22,077)
Capital expenditures and other assets	(15,042)	(12,100)
Proceeds from sales of property, plant and equipment and assets held for sale	0	9,024
Proceeds from sale of Audio Entertainment Group (AEG) segment	0	1,625
Cash used for investing activities	(6,129)	(152,665)
CASH FLOWS FROM FINANCING ACTIVITIES
Repurchase of common stock	(229,121)	(70,270)
Equity forward contract related to accelerated share repurchase program	(15,000)	0
Proceeds from sale of treasury stock	2,519	2,033
Proceeds from issuance of common stock	27,072	44,703
Proceeds from revolving line of credit	53,500	0
Repayments of revolving line of credit	(14,000)	0
Payment of cash dividends	(6,884)	(7,263)
Employees taxes withheld and paid for restricted stock and restricted stock units	(2,457)	(74)
Excess tax benefit from stock-based compensation	5,147	4,900
Cash used for financing activities	(179,224)	(25,971)
Effect of exchange rate changes on cash and cash equivalents	(1,428)	93
Net decrease in cash and cash equivalents	(99,310)	(92,074)
Cash and cash equivalents at beginning of period	277,373	349,961
Cash and cash equivalents at end of period	$ 178,063	$ 257,887