Condensed Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 27, 2015	Jun. 28, 2014	Jun. 27, 2015	Jun. 28, 2014
Net revenues:
Products	$ 38,937	$ 39,224	$ 77,275	$ 82,504
Service	9,692	8,805	21,730	17,101
Total net revenues	48,629	48,029	99,005	99,605
Costs of net revenues:
Cost of products	19,872	19,789	39,863	41,428
Cost of service	5,036	4,655	11,410	9,769
Amortization of intangible assets	457	677	1,089	1,351
Total costs of net revenues	25,365	25,121	52,362	52,548
Gross profit	23,264	22,908	46,643	47,057
Operating expenses:
Research and development	8,157	9,373	16,316	17,687
Selling	7,029	6,681	14,145	14,054
General and administrative	5,544	6,001	11,310	12,339
Amortization of intangible assets	25	107	64	215
Restructuring charge	0	0	58	0
Total operating expenses	20,755	22,162	41,893	44,295
Income from operations	2,509	746	4,750	2,762
Other income (expense):
Interest income	46	10	56	24
Interest expense	(83)	(96)	(165)	(196)
Other income, net	(311)	(84)	393	168
Total other income (expense), net	(348)	(170)	284	(4)
Income before income taxes	2,161	576	5,034	2,758
Provision (benefit) for income taxes	817	(12)	1,134	575
Net income	$ 1,344	$ 588	$ 3,900	$ 2,183
Net income per share:
Basic (in dollars per share)	$ 0.06	$ 0.02	$ 0.16	$ 0.09
Diluted (in dollars per share)	$ 0.06	$ 0.02	$ 0.16	$ 0.09
Weighted average shares used in per share calculation:
Basic (in shares)	24,020	23,939	23,943	23,825
Diluted (in shares)	24,285	24,220	24,260	24,217