Consolidated Condensed Statements Of Cash Flows (USD $) In Thousands	6 Months Ended
Jul. 31, 2011	Aug. 01, 2010
Cash flows from operating activities:
Net income	$ 49,720	$ 30,464
Adjustments to reconcile net income to net cash provided by operations:
Depreciation and amortization	8,811	7,855
Deferred income taxes	6,239	1,572
Stock-based compensation	12,108	15,506
Excess tax benefits on stock based compensation	(1,719)	(233)
Loss on disposition of property, plant and equipment	7	63
Changes in assets and liabilities:
Receivables, net	(693)	(17,846)
Inventories	(1,526)	(3,079)
Prepaid expenses and other assets	(7,409)	(8,762)
Accounts payable	4,459	9,303
Accrued liabilities	(30,869)	(283)
Deferred revenue	682	660
Income taxes payable and prepaid taxes	341	(844)
Other liabilities	435	652
Net cash provided by operations	40,586	35,028
Cash flows from investing activities:
Purchase of available-for-sale investments	(83,830)	(81,895)
Proceeds from sales and maturities of available-for-sale investments	50,004	48,268
Proceeds from sale of property, plant and equipment	5	51
Purchases of property, plant and equipment	(15,259)	(10,342)
Net cash used in investing activities	(49,080)	(43,918)
Cash flows from financing activities:
Excess tax benefits on stock based compensation	1,719	233
Proceeds from issuance of common stock	28,896	7,379
Repurchase of outstanding common stock	(551)	(1,402)
Net cash provided by financing activities	30,064	6,210
Net increase (decrease) in cash and cash equivalents	21,570	(2,680)
Cash and cash equivalents at beginning of period	119,019	80,598
Cash and cash equivalents at end of period	$ 140,589	$ 77,918

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Includes currency on hand as well as demand deposits with banks or financial institutions. It also includes other kinds of accounts that have the general characteristics of demand deposits in that the Entity may deposit additional funds at any time and also effectively may withdraw funds at any time without prior notice or penalty. Cash equivalents, excluding items classified as marketable securities, include short-term, highly liquid investments that are both readily convertible to known amounts of cash, and so near their maturity that they present minimal risk of changes in value because of changes in interest rates. Generally, only investments with original maturities of three months or less qualify under that definition. Original maturity means original maturity to the entity holding the investment. For example, both a three-month US Treasury bill and a three-year Treasury note purchased three months from maturity qualify as cash equivalents. However, a Treasury note purchased three years ago does not become a cash equivalent when its remaining maturity is three months. Compensating balance arrangements that do not legally restrict the withdrawal or usage of cash amounts may be reported as Cash and Cash Equivalents, while legally restricted deposits held as compensating balances against borrowing arrangements, contracts entered into with others, or company statements of intention with regard to particular deposits are not generally reported as cash and cash equivalents. Includes cash and cash equivalents associated with the entity's continuing operations. Excludes cash and cash equivalents associated with the disposal group (and discontinued operation).