Condensed Consolidated Statements of Operations - USD ($) shares in Thousands	3 Months Ended		9 Months Ended
	Sep. 24, 2016	Sep. 26, 2015	Sep. 24, 2016	Sep. 26, 2015
Net revenues:
Products	$ 49,631,000	$ 36,414,000	$ 136,290,000	$ 113,689,000
Service	9,083,000	9,264,000	25,680,000	30,993,000
Total net revenues	58,714,000	45,678,000	161,970,000	144,682,000
Costs of net revenues:
Cost of products	22,810,000	19,242,000	62,625,000	59,106,000
Cost of service	5,066,000	3,749,000	14,714,000	15,158,000
Amortization of intangible assets	434,000	468,000	1,311,000	1,557,000
Total costs of net revenues	28,310,000	23,459,000	78,650,000	75,821,000
Gross profit	30,404,000	22,219,000	83,320,000	68,861,000
Operating expenses:
Research and development	7,868,000	8,579,000	23,447,000	24,896,000
Selling	7,495,000	6,760,000	22,567,000	20,905,000
General and administrative	5,975,000	5,590,000	17,150,000	16,901,000
Amortization of intangible assets		26,000	24,000	89,000
Restructuring charge			0	56,000
Total operating expenses	21,338,000	20,955,000	63,188,000	62,847,000
Income from operations	9,066,000	1,264,000	20,132,000	6,014,000
Other (income) expense:
Interest income	12,000	7,000	33,000	63,000
Interest expense	(92,000)	(86,000)	(276,000)	(252,000)
Other income, net	229,000	346,000	60,000	740,000
Total other income (expense), net	149,000	267,000	(183,000)	551,000
Income before income taxes	9,215,000	1,531,000	19,949,000	6,565,000
Provision for income taxes	1,332,000	713,000	2,568,000	1,847,000
Net income	$ 7,883,000	$ 818,000	$ 17,381,000	$ 4,718,000
Net income per share:
Basic (in dollars per share)	$ 0.32	$ 0.03	$ 0.71	$ 0.20
Diluted (in dollars per share)	$ 0.31	$ 0.03	$ 0.70	$ 0.19
Weighted average shares used in per share calculation:
Basic (in shares)	24,826	24,145	24,550	24,010
Diluted (in shares)	25,282	24,352	24,979	24,347