Consolidated Statements of Operations (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 27, 2014	Dec. 28, 2013	Dec. 29, 2012
Net revenues:
Products	$ 133,589	$ 107,402	$ 143,827
Service	32,854	36,905	39,054
Total net revenues	166,443	144,307	182,881
Costs of net revenues:
Cost of products	68,812	59,509	75,878
Cost of service	19,086	19,489	20,526
Amortization of intangible assets	2,723	2,633	2,549
Total costs of net revenues	90,621	81,631	98,953
Gross profit	75,822	62,676	83,928
Operating expenses:
Research and development	33,776	32,714	29,585
Selling	27,033	27,129	26,457
General and administrative	23,980	22,101	21,632
Amortization of intangible assets	420	701	776
Restructuring charge	2,266	1,740	0
Total operating expenses	87,475	84,385	78,450
Income (loss) from operations	(11,653)	(21,709)	5,478
Other (income) expense:
Interest income	47	62	133
Interest expense	(389)	(651)	(1,040)
Other income (expense), net	374	(1,267)	48
Total other income (expense), net	32	(1,856)	(859)
Income (loss) before income taxes	(11,621)	(23,565)	4,619
Provision for (benefit from) income taxes	19,497	(9,419)	154
Net income (loss)	$ (31,118)	$ (14,146)	$ 4,465
Net income (loss) per share:
Basic (in dollars per share)	$ (1.30)	$ (0.61)	$ 0.19
Diluted (in dollars per share)	$ (1.30)	$ (0.61)	$ 0.19
Weighted average shares used in per share calculation:
Basic (in shares)	23,958	23,290	23,358
Diluted (in shares)	23,958	23,290	23,845