Consolidated Condensed Statements Of Cash Flows (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Oct. 30, 2011	Oct. 31, 2010
Cash flows from operating activities:
Net income	$ 76,699	$ 46,569
Adjustments to reconcile net income to net cash provided by operations:
Depreciation and amortization	13,614	12,267
Deferred income taxes	5,209	1,909
Impairment of acquired intangible assets	2,470
Stock-based compensation	17,149	22,925
Excess tax benefits on stock based compensation	(2,327)	(281)
(Gain) loss on disposition of property, plant and equipment	(6)	69
Changes in assets and liabilities:
Accounts receivable, net	(9,004)	(27,748)
Inventories	560	(9,454)
Prepaid expenses and other assets	(8,115)	(3,051)
Accounts payable	6,579	12,630
Accrued liabilities	(27,629)	13,899
Deferred revenue	(397)	1,934
Income taxes payable and prepaid taxes	(881)	(9,271)
Other liabilities	(353)	2,209
Net cash provided by operations	73,568	64,606
Cash flows from investing activities:
Purchase of available-for-sale investments	(90,331)	(148,802)
Proceeds from sales and maturities of available-for-sale investments	95,122	84,961
Proceeds from sale of property, plant and equipment	18	76
Purchases of property, plant and equipment	(18,007)	(18,016)
Purchase of intangible assets	(3,000)
Net cash used in investing activities	(16,198)	(81,781)
Cash flows from financing activities:
Excess tax benefits on stock based compensation	2,327	281
Proceeds from issuance of common stock	35,005	22,218
Repurchase of outstanding common stock	(30,579)	(2,714)
Net cash provided by financing activities	6,753	19,785
Effect of foreign currency translation on cash and cash equivalents	(2)	1
Net increase in cash and cash equivalents	64,121	2,611
Cash and cash equivalents at beginning of period	119,019	80,598
Cash and cash equivalents at end of period	$ 183,140	$ 83,209