Condensed Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 24, 2016	Sep. 30, 2017	Sep. 24, 2016
Net revenues:
Products	$ 45,571	$ 49,631	$ 147,322	$ 136,290
Service	11,104	9,083	33,094	25,680
Total net revenues	56,675	58,714	180,416	161,970
Costs of net revenues:
Cost of products	21,349	22,810	72,164	62,625
Cost of service	4,614	5,066	15,368	14,714
Amortization of intangible assets	52	434	156	1,311
Total costs of net revenues	26,015	28,310	87,688	78,650
Gross profit	30,660	30,404	92,728	83,320
Operating expenses:
Research and development	8,825	7,868	26,658	23,447
Selling	7,553	7,495	22,730	22,567
General and administrative	6,798	5,975	19,696	17,150
Amortization of intangible assets	0	0	0	24
Total operating expenses	23,176	21,338	69,084	63,188
Income from operations	7,484	9,066	23,644	20,132
Other income (expense):
Interest income	2	12	6	33
Interest expense	(25)	(92)	(84)	(276)
Other income, net	59	229	330	60
Total other income (expense), net	36	149	252	(183)
Income before income taxes	7,520	9,215	23,896	19,949
Provision for income taxes	1,756	1,332	4,492	2,568
Net income	$ 5,764	$ 7,883	$ 19,404	$ 17,381
Net income per share:
Basic (in dollars per share)	$ 0.23	$ 0.32	$ 0.77	$ 0.71
Diluted (in dollars per share)	$ 0.22	$ 0.31	$ 0.75	$ 0.70
Weighted average shares used in per share calculation:
Basic (in shares)	25,494	24,826	25,320	24,550
Diluted (in shares)	25,932	25,282	25,933	24,979