Consolidated Statements Of Income (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Jan. 29, 2012	Oct. 30, 2011	Jul. 31, 2011	May 01, 2011	Jan. 30, 2011	Oct. 31, 2010	Aug. 01, 2010	May 02, 2010	Jan. 29, 2012	Jan. 30, 2011	Jan. 31, 2010
Consolidated Statements Of Income [Abstract]
Net Sales	$ 104,032	$ 123,944	$ 130,254	$ 122,371	$ 116,270	$ 123,125	$ 113,227	$ 101,880	$ 480,601	$ 454,502	$ 286,560
Cost of Sales	44,368	50,537	51,534	48,517	46,264	49,304	45,795	44,833	194,956	186,196	130,514
Gross Profit	59,664	73,407	78,720	73,854	70,006	73,821	67,432	57,047	285,645	268,306	156,046
Operating costs and expenses:
Selling, general and administrative	26,333	25,110	22,481	26,705	23,637	35,501	24,915	26,351	100,629	110,404	77,934
Product development & engineering	19,335	20,489	22,228	18,525	18,517	18,400	17,404	15,303	80,577	69,624	44,847
Intangible amortization and impairments	2,075	4,573	2,103	2,102	2,304	2,406	2,405	2,405	10,853	9,520	2,348
Total operating costs and expenses	47,743	50,172	46,812	47,332	44,458	56,307	44,724	44,059	192,059	189,548	125,129
Operating income	11,921	23,235	31,908	26,522	25,548	17,514	22,708	12,988	93,586	78,758	30,917
Interest and other income, net	421	729	(117)	(440)	66	3	308	197	593	574	3,054
Income before taxes	12,342	23,964	31,791	26,082	25,614	17,517	23,016	13,185	94,179	79,332	33,971
Provision for taxes	(46)	(3,015)	4,653	3,500	(389)	1,412	3,354	2,383	5,092	6,760	33,014
NET INCOME	$ 12,388	$ 26,979	$ 27,138	$ 22,582	$ 26,003	$ 16,105	$ 19,662	$ 10,802	$ 89,087	$ 72,572	$ 957
Earnings per share:
Basic	$ 0.19	$ 0.41	$ 0.41	$ 0.35	$ 0.41	$ 0.26	$ 0.32	$ 0.18	$ 1.37	$ 1.16	$ 0.02
Diluted	$ 0.19	$ 0.40	$ 0.40	$ 0.34	$ 0.39	$ 0.25	$ 0.31	$ 0.17	$ 1.32	$ 1.12	$ 0.02
Weighted average number of shares used in computing earnings per share:
Basic	64,856	65,440	65,547	64,552	63,506	62,493	61,933	61,420	65,099	62,339	60,779
Diluted	66,776	67,314	68,186	67,123	66,213	64,555	63,552	63,181	67,350	64,523	61,676