Consolidated Statements of Operations (Unaudited) (USD $) In Thousands, except Per Share data	3 Months Ended		6 Months Ended
	Jul. 03, 2011	Jul. 04, 2010	Jul. 03, 2011	Jul. 04, 2010
Revenue
Product	$ 77,566	$ 67,067	$ 146,443	$ 121,680
Service	5,827	4,744	11,344	9,098
Total revenue	83,393	71,811	157,787	130,778
Cost of revenue
Product	16,454	15,914	31,553	28,825
Service	2,925	2,803	6,209	5,833
Total cost of revenue	19,379	18,717	37,762	34,658
Gross margin
Product	61,112	51,153	114,890	92,855
Service	2,902	1,941	5,135	3,265
Total gross margin	64,014	53,094	120,025	96,120
Research, development, and engineering expenses	10,506	8,076	19,988	16,179
Selling, general, and administrative expenses	29,466	25,738	58,627	49,360
Restructuring charges		39		88
Operating income	24,042	19,241	41,410	30,493
Foreign currency gain (loss)	210	(8)	151	(173)
Investment income	697	308	1,302	565
Other expense	(148)	(156)	(353)	(402)
Income before income tax expense	24,801	19,385	42,510	30,483
Income tax expense	5,704	4,458	9,777	7,011
Net income	$ 19,097	$ 14,927	$ 32,733	$ 23,472
Earnings per weighted-average common and common-equivalent share:
Basic	$ 0.46	$ 0.38	$ 0.79	$ 0.59
Diluted	$ 0.45	$ 0.38	$ 0.77	$ 0.59
Weighted-average common and common-equivalent shares outstanding:
Basic	41,842	39,683	41,586	39,675
Diluted	42,810	39,793	42,532	39,736
Cash dividends per common share	$ 0.09	$ 0.06	$ 0.17	$ 0.11