Consolidated Statements of Operations (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jul. 01, 2012	Jul. 03, 2011	Jul. 01, 2012	Jul. 03, 2011
Net sales:
Products	$ 172,644	$ 168,896	$ 341,988	$ 324,928
Service and components	48,808	42,245	97,019	83,173
Total net sales	221,452	211,141	439,007	408,101
Cost of sales:
Products	85,993	86,256	173,331	169,851
Service and components	31,030	29,190	63,136	56,651
Total cost of sales	117,023	115,446	236,467	226,502
Gross profit	104,429	95,695	202,540	181,599
Operating expenses:
Research and development	23,306	19,619	46,028	37,559
Selling, general and administrative	42,045	38,774	83,368	74,556
Restructuring, reorganization, relocation and severance	0	783	0	1,068
Total operating expenses	65,351	59,176	129,396	113,183
Operating income	39,078	36,519	73,144	68,416
Other expense:
Interest income	384	689	955	1,181
Interest expense	(1,003)	(1,133)	(2,087)	(2,175)
Other, net	(636)	(449)	(2,186)	(121)
Total other expense, net	(1,255)	(893)	(3,318)	(1,115)
Income before income taxes	37,823	35,626	69,826	67,301
Income tax expense	7,530	9,566	13,866	18,929
Net income	$ 30,293	$ 26,060	$ 55,960	$ 48,372
Basic net income per share	$ 0.80	$ 0.67	$ 1.48	$ 1.25
Diluted net income per share	$ 0.74	$ 0.62	$ 1.37	$ 1.16
Cash dividends declared per share	$ 0.08	$ 0.00	$ 0.08	$ 0.00
Shares used in per share calculations:
Basic (in shares)	37,993	38,883	37,939	38,686
Diluted (in shares)	41,614	42,566	41,579	42,359