Consolidated Statements of Income - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 30, 2017		Dec. 31, 2016		Dec. 26, 2015
Net sales	$ 352,704		$ 282,084	[1]	$ 269,654
Cost and expenses:
Cost of sales	211,986		187,256		180,616
Research and development	40,737		34,841		33,107
Selling, general and administrative	65,233		54,322		51,170
Gain on sale of facility					(3,198)
	317,956		276,419		261,695
Income from operations	34,748		5,665		7,959
Interest income	617		342		44
Income from continuing operations before taxes	35,365		6,007		8,003
Income tax provision	2,244		2,747		2,211
Income from continuing operations	33,121		3,260	[2]	5,792
Loss from discontinued operations, net of tax	(278)		(221)		(5,542)
Net income	$ 32,843		$ 3,039	[2]	$ 250
Basic:
Income from continuing operations (in dollars per share)	$ 1.19	[3]	$ 0.12	[2],[3]	$ 0.22
Loss from discontinued operations (in dollars per share)	(0.01)		(0.01)		(0.21)
Net income (in dollars per share)	1.18	[3]	0.11	[2],[3]	0.01
Diluted:
Income from continuing operations (in dollars per share)	1.15	[3]	0.12	[2],[3]	0.22
Loss from discontinued operations (in dollars per share)	(0.01)		(0.01)		(0.21)
Net income (in dollars per share)	$ 1.14	[3]	$ 0.11	[2],[3]	$ 0.01
Weighted average shares used in computing income (loss) per share:
Basic (in shares)	27,836		26,659		26,057
Diluted (in shares)	28,916		27,480		26,788

[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.