Consolidated Statements of Operations (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 30, 2014	Mar. 31, 2013
Net sales:
Products	$ 169,298	$ 169,495
Service	56,966	51,694
Total net sales	226,264	221,189
Cost of sales:
Products	86,595	85,183
Service	33,345	33,455
Total cost of sales	119,940	118,638
Gross profit	106,324	102,551
Operating expenses:
Research and development	25,646	24,809
Selling, general and administrative	48,462	43,524
Restructuring, reorganization, relocation and severance	1,331	695
Total operating expenses	75,439	69,028
Operating income	30,885	33,523
Other expense:
Interest income	152	116
Interest expense	(98)	(816)
Other, net	(324)	(805)
Total other expense, net	(270)	(1,505)
Income before income taxes	30,615	32,018
Income tax expense	5,537	5,217
Net income	$ 25,078	$ 26,801
Basic net income per share	$ 0.59	$ 0.70
Diluted net income per share	$ 0.59	$ 0.65
Cash dividends declared per share	$ 0.12	$ 0.08
Shares used in per share calculations:
Basic	42,191	38,522
Diluted	42,772	42,136