Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 26, 2015	Dec. 27, 2014
Net revenues:
Products	$ 185,066	$ 146,945	$ 133,589
Service	36,063	40,422	32,854
Total net revenues	221,129	187,367	166,443
Costs of net revenues:
Cost of products	85,391	76,224	68,812
Cost of service	20,160	19,450	19,086
Amortization of intangible assets	1,454	2,026	2,723
Total costs of net revenues	107,005	97,700	90,621
Gross profit	114,124	89,667	75,822
Operating expenses:
Research and development	31,443	32,701	33,776
Selling	30,181	28,055	27,033
General and administrative	23,381	22,444	23,980
Amortization of intangible assets	24	114	420
Restructuring charge	0	1,380	2,266
Total operating expenses	85,029	84,694	87,475
Income (loss) from operations	29,095	4,973	(11,653)
Other (income) expense:
Interest income	35	71	47
Interest expense	(285)	(289)	(389)
Other income (expense), net	290	813	374
Total other income (expense), net	40	595	32
Income (loss) before income taxes	29,135	5,568	(11,621)
Provision for (benefit from) income taxes	(14,900)	2,663	19,497
Net income (loss)	$ 44,035	$ 2,905	$ (31,118)
Net income (loss) per share:
Basic (in dollars per share)	$ 1.79	$ 0.12	$ (1.30)
Diluted (in dollars per share)	$ 1.75	$ 0.12	$ (1.30)
Weighted average shares used in per share calculation:
Basic (in shares)	24,655	24,059	23,958
Diluted (in shares)	25,153	24,375	23,958