Consolidated Condensed Statements Of Operations (USD $) In Thousands, except Per Share data	3 Months Ended		6 Months Ended
	Jul. 31, 2011	Aug. 01, 2010	Jul. 31, 2011	Aug. 01, 2010
Consolidated Condensed Statements Of Operations
Net sales	$ 130,254	$ 113,227	$ 252,625	$ 215,107
Cost of sales	51,534	45,795	100,051	90,628
Gross profit	78,720	67,432	152,574	124,479
Operating costs and expenses:
Selling, general and administrative	22,481	24,915	49,186	51,266
Product development and engineering	22,228	17,404	40,753	32,707
Intangible amortization	2,103	2,405	4,205	4,810
Total operating costs and expenses	46,812	44,724	94,144	88,783
Operating income	31,908	22,708	58,430	35,696
Interest and other (expense) income, net	(117)	308	(557)	505
Income before taxes	31,791	23,016	57,873	36,201
Provision for taxes	4,653	3,354	8,153	5,737
Net Income	$ 27,138	$ 19,662	$ 49,720	$ 30,464
Earnings per share:
Basic	$ 0.41	$ 0.32	$ 0.76	$ 0.49
Diluted	$ 0.40	$ 0.31	$ 0.74	$ 0.48
Weighted average number of shares used in computing earnings per share:
Basic	65,547	61,933	65,050	61,679
Diluted	68,186	63,552	67,638	63,264