Consolidated Statements of Operations (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Apr. 01, 2012
Net sales:
Products	$ 169,495	$ 169,344
Service	51,694	48,211
Total net sales	221,189	217,555
Cost of sales:
Products	85,183	87,338
Service	33,455	32,106
Total cost of sales	118,638	119,444
Gross profit	102,551	98,111
Operating expenses:
Research and development	24,809	22,722
Selling, general and administrative	43,524	41,323
Restructuring, reorganization, relocation and severance	695	0
Total operating expenses	69,028	64,045
Operating income	33,523	34,066
Other expense:
Interest income	116	571
Interest expense	(816)	(1,084)
Other, net	(805)	(1,550)
Total other expense, net	(1,505)	(2,063)
Income before income taxes	32,018	32,003
Income tax expense	5,217	6,336
Net income	$ 26,801	$ 25,667
Basic net income per share	$ 0.70	$ 0.68
Diluted net income per share	$ 0.65	$ 0.63
Cash dividends declared per share	$ 0.08	$ 0.00
Shares used in per share calculations:
Basic (in shares)	38,522	37,886
Diluted (in shares)	42,136	41,518