CONSOLIDATED STATEMENTS OF OPERATIONS (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Apr. 01, 2012
Revenue
Product	$ 74,672	$ 71,407
Service	6,220	6,302
Total revenue	80,892	77,709
Cost of revenue
Product	16,464	15,556
Service	2,959	3,502
Total cost of revenue	19,423	19,058
Gross margin
Product	58,208	55,851
Service	3,261	2,800
Total gross margin	61,469	58,651
Research, development, and engineering expenses	11,321	10,361
Selling, general, and administrative expenses	32,167	30,549
Operating income	17,981	17,741
Foreign currency gain (loss)	63	(638)
Investment income	392	972
Other income	117	3
Income before income tax expense	18,553	18,078
Income tax expense	2,970	3,796
Net income	$ 15,583	$ 14,282
Earnings per weighted-average common and common-equivalent share:
Basic	$ 0.36	$ 0.34
Diluted	$ 0.35	$ 0.33
Weighted-average common and common-equivalent shares outstanding:
Basic	43,261	42,570
Diluted	44,130	43,590
Cash dividends per common share	$ 0.00	$ 0.10