Condensed Consolidated Statements of Operations - USD ($) shares in Thousands	3 Months Ended		6 Months Ended
	Jun. 25, 2016	Jun. 27, 2015	Jun. 25, 2016	Jun. 27, 2015
Net revenues:
Products	$ 47,445,000	$ 38,937,000	$ 86,659,000	$ 77,275,000
Service	8,322,000	9,692,000	16,597,000	21,730,000
Total net revenues	55,767,000	48,629,000	103,256,000	99,005,000
Costs of net revenues:
Cost of products	21,736,000	19,872,000	39,815,000	39,863,000
Cost of service	5,164,000	5,036,000	9,648,000	11,410,000
Amortization of intangible assets	442,000	457,000	877,000	1,089,000
Total costs of net revenues	27,342,000	25,365,000	50,340,000	52,362,000
Gross profit	28,425,000	23,264,000	52,916,000	46,643,000
Operating expenses:
Research and development	7,511,000	8,157,000	15,579,000	16,316,000
Selling	7,823,000	7,029,000	15,072,000	14,145,000
General and administrative	5,755,000	5,544,000	11,175,000	11,310,000
Amortization of intangible assets		25,000	24,000	64,000
Restructuring charge			0	58,000
Total operating expenses	21,089,000	20,755,000	41,850,000	41,893,000
Income from operations	7,336,000	2,509,000	11,066,000	4,750,000
Other (income) expense:
Interest income	12,000	46,000	21,000	56,000
Interest expense	(67,000)	(83,000)	(184,000)	(165,000)
Other income, net	(394,000)	(311,000)	(169,000)	393,000
Total other income (expense), net	(449,000)	(348,000)	(332,000)	284,000
Income before income taxes	6,887,000	2,161,000	10,734,000	5,034,000
Provision for income taxes	856,000	817,000	1,236,000	1,134,000
Net income	$ 6,031,000	$ 1,344,000	$ 9,498,000	$ 3,900,000
Net income per share:
Basic (in dollars per share)	$ 0.25	$ 0.06	$ 0.39	$ 0.16
Diluted (in dollars per share)	$ 0.24	$ 0.06	$ 0.38	$ 0.16
Weighted average shares used in per share calculation:
Basic (in shares)	24,524	24,020	24,416	23,943
Diluted (in shares)	24,927	24,285	24,773	24,260