Consolidated Statements of Income - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2016		Dec. 26, 2015		Dec. 27, 2014
Net sales	$ 282,084	[1]	$ 269,654	[1]	$ 316,629
Cost and expenses:
Cost of sales	187,256		180,616		210,657
Research and development	34,841		33,107		36,018
Selling, general and administrative	54,322		51,170		50,551
Gain on sale of facility			(3,198)
	276,419		261,695		297,226
Income from operations	5,665		7,959		19,403
Interest income	342		44		30
Income from continuing operations before taxes	6,007		8,003		19,433
Income tax provision	2,747		2,211		4,653
Income from continuing operations	3,260	[1],[2]	5,792	[1]	14,780
Loss from discontinued operations, net of tax	(221)		(5,542)		(6,072)
Net income	$ 3,039	[1],[2]	$ 250	[1]	$ 8,708
Basic:
Income from continuing operations (in dollars per share)	$ 0.12	[1],[2],[3]	$ 0.22	[1],[3]	$ 0.58
Loss from discontinued operations (in dollars per share)	(0.01)		(0.21)		(0.24)
Net income (in dollars per share)	0.11	[1],[2],[3]	0.01	[1],[3]	0.34
Diluted:
Income from continuing operations (in dollars per share)	0.12	[1],[2]	0.22	[1]	0.57
Loss from discontinued operations (in dollars per share)	(0.01)		(0.21)		(0.24)
Net income (in dollars per share)	$ 0.11	[1],[2]	$ 0.01	[1]	$ 0.33
Weighted average shares used in computing income (loss) per share:
Basic (in shares)	26,659		26,057		25,393
Diluted (in shares)	27,480		26,788		26,006

[1] All quarters presented above were comprised of 13 weeks, except for the fourth quarter ended December 31, 2016 which was comprised of 14 weeks.

[2] As a result of the adoption of ASU 2016-09, in the fourth quarter of 2016, certain amounts in the first three quarters have been restated as if the new accounting guidance was adopted starting with the first day of our 2016 fiscal year. The impact of these restatements was not significant.

[3] The sum of the four quarters may not agree to the year total due to rounding within a quarter and the inclusion or exclusion of common stock equivalents.