CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands	3 Months Ended
	Jun. 30, 2011	Jun. 30, 2010
CASH FLOWS FROM OPERATING ACTIVITIES
Net income	$ 26,731	$ 25,946
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	3,462	3,992
Stock-based compensation	4,179	3,777
Provision for (benefit from) sales allowances and doubtful accounts	(41)	115
Provision for (benefit from) excess and obsolete inventories	322	(273)
Benefit from deferred income taxes	(2,144)	(1,249)
Income tax benefit associated with stock option exercises	1,381	797
Excess tax benefit from stock-based compensation	(2,570)	(648)
Amortization of premium on investments, net	431	0
Other operating activities	172	41
Changes in assets and liabilities:
Accounts receivable, net	(5,607)	(7,264)
Inventory, net	(1,453)	(7,509)
Current and other assets	(2,420)	(928)
Accounts payable	(6,684)	6,728
Accrued liabilities	(5,067)	102
Income taxes	8,531	8,420
Cash provided by operating activities	19,223	32,047
CASH FLOWS FROM INVESTING ACTIVITIES
Proceeds from sales of short-term investments	62,968	23,250
Proceeds from maturities of short-term investments	31,300	0
Purchase of short-term investments	(63,061)	0
Proceeds from sales of long-term investments	4,936	0
Purchase of long-term investments	(35,145)	0
Capital expenditures and other assets	(3,935)	(3,007)
Cash (used for) provided by investing activities	(2,937)	20,243
CASH FLOWS FROM FINANCING ACTIVITIES
Repurchase of common stock	(90,668)	(43,706)
Equity forward contract related to accelerated share repurchase program	(18,872)	0
Proceeds from sale of treasury stock	0	13
Proceeds from issuance of common stock	11,515	7,666
Payment of cash dividends	(2,427)	(2,456)
Employees' taxes withheld and paid for restricted stock and restricted stock units	(705)	0
Excess tax benefit from stock-based compensation	2,570	648
Cash used for financing activities	(98,587)	(37,835)
Effect of exchange rate changes on cash and cash equivalents	673	(1,386)
Net (decrease) increase in cash and cash equivalents	(81,628)	13,069
Cash and cash equivalents at beginning of period	284,375	349,961
Cash and cash equivalents at end of period	$ 202,747	$ 363,030