Condensed Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 26, 2015	Sep. 27, 2014	Sep. 26, 2015	Sep. 27, 2014
Net revenues:
Products	$ 36,414	$ 19,487	$ 113,689	$ 101,991
Service	9,264	7,646	30,993	24,747
Total net revenues	45,678	27,133	144,682	126,738
Costs of net revenues:
Cost of products	19,242	10,737	59,106	52,165
Cost of service	3,749	4,292	15,158	14,061
Amortization of intangible assets	468	688	1,557	2,039
Total costs of net revenues	23,459	15,717	75,821	68,265
Gross profit	22,219	11,416	68,861	58,473
Operating expenses:
Research and development	8,579	8,037	24,896	25,724
Selling	6,760	6,389	20,905	20,443
General and administrative	5,590	5,781	16,901	18,120
Amortization of intangible assets	26	103	89	318
Restructuring charge	0	1,715	56	1,715
Total operating expenses	20,955	22,025	62,847	66,320
Income (loss) from operations	1,264	(10,609)	6,014	(7,847)
Other income (expense):
Interest income	7	13	63	37
Interest expense	(86)	(90)	(252)	(286)
Other income, net	346	(57)	740	111
Total other income (expense), net	267	(134)	551	(138)
Income (loss) before income taxes	1,531	(10,743)	6,565	(7,985)
Provision for income taxes	713	17,919	1,847	18,494
Net income (loss)	$ 818	$ (28,662)	$ 4,718	$ (26,479)
Net income (loss) per share:
Basic (in dollars per share)	$ 0.03	$ (1.19)	$ 0.20	$ (1.11)
Diluted (in dollars per share)	$ 0.03	$ (1.19)	$ 0.19	$ (1.11)
Weighted average shares used in per share calculation:
Basic (in shares)	24,145	24,132	24,010	23,928
Diluted (in shares)	24,352	24,132	24,347	23,928