Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 26, 2015	Dec. 27, 2014	Dec. 28, 2013
Net revenues:
Products	$ 146,945	$ 133,589	$ 107,402
Service	40,422	32,854	36,905
Total net revenues	187,367	166,443	144,307
Costs of net revenues:
Cost of products	76,224	68,812	59,509
Cost of service	19,450	19,086	19,489
Amortization of intangible assets	2,026	2,723	2,633
Total costs of net revenues	97,700	90,621	81,631
Gross profit	89,667	75,822	62,676
Operating expenses:
Research and development	32,701	33,776	32,714
Selling	28,055	27,033	27,129
General and administrative	22,444	23,980	22,101
Amortization of intangible assets	114	420	701
Restructuring charge	1,380	2,266	1,740
Total operating expenses	84,694	87,475	84,385
Income (loss) from operations	4,973	(11,653)	(21,709)
Other (income) expense:
Interest income	71	47	62
Interest expense	(289)	(389)	(651)
Other income (expense), net	813	374	(1,267)
Total other income (expense), net	595	32	(1,856)
Income (loss) before income taxes	5,568	(11,621)	(23,565)
Provision for (benefit from) income taxes	2,663	19,497	(9,419)
Net income (loss)	$ 2,905	$ (31,118)	$ (14,146)
Net income (loss) per share:
Basic (in dollars per share)	$ 0.12	$ (1.30)	$ (0.61)
Diluted (in dollars per share)	$ 0.12	$ (1.30)	$ (0.61)
Weighted average shares used in per share calculation:
Basic (in shares)	24,059	23,958	23,290
Diluted (in shares)	24,375	23,958	23,290