Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 03, 2016	Jun. 28, 2015	Jul. 03, 2016	Jun. 28, 2015
Net sales:
Products	$ 191,161	$ 163,585	$ 353,439	$ 327,644
Service	68,204	60,604	134,570	117,361
Total net sales	259,365	224,189	488,009	445,005
Cost of sales:
Products	93,645	78,825	176,310	160,326
Service	39,275	33,259	77,982	67,303
Total cost of sales	132,920	112,084	254,292	227,629
Gross profit	126,445	112,105	233,717	217,376
Operating expenses:
Research and development	29,968	23,128	57,613	46,450
Selling, general and administrative	64,117	43,093	113,356	88,915
Restructuring and reorganization	0	(21)	(102)	(142)
Total operating expenses	94,085	66,200	170,867	135,223
Operating income	32,360	45,905	62,850	82,153
Other expense:
Interest income	199	254	383	465
Interest expense	(349)	(140)	(803)	(234)
Other, net	(1,016)	(704)	(1,837)	(1,788)
Total other expense, net	(1,166)	(590)	(2,257)	(1,557)
Income before income taxes	31,194	45,315	60,593	80,596
Income tax expense	6,254	7,983	12,751	15,252
Net income	$ 24,940	$ 37,332	$ 47,842	$ 65,344
Basic net income per share	$ 0.61	$ 0.90	$ 1.17	$ 1.57
Diluted net income per share	0.60	0.89	1.16	1.55
Cash dividends declared per share	$ 0.3	$ 0.3	$ 0.6	$ 0.55
Shares used in per share calculations:
Basic (in shares)	40,922	41,629	40,890	41,711
Diluted (in shares)	41,389	42,044	41,304	42,142