Condensed Consolidated Statements of Income (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 24, 2017	Jun. 25, 2016	Jun. 24, 2017	Jun. 25, 2016
Net sales	$ 93,866	$ 76,353	$ 174,963	$ 142,131
Cost and expenses:
Cost of sales	56,736	49,614	105,577	96,110
Research and development	9,466	8,345	19,242	16,025
Selling, general and administrative	16,020	15,175	30,480	28,289
	82,222	73,134	155,299	140,424
Income from operations	11,644	3,219	19,664	1,707
Interest and other, net	142	59	243	102
Income from continuing operations before taxes	11,786	3,278	19,907	1,809
Income tax provision	1,078	761	2,436	983
Income from continuing operations	10,708	2,517	17,471	826
Loss from discontinued operations	(278)	(55)	(278)	(55)
Net income	$ 10,430	$ 2,462	$ 17,193	$ 771
Basic:
Income from continuing operations (in dollars per share)	$ 0.39	$ 0.09	$ 0.64	$ 0.03
Loss from discontinued operations (in dollars per share)	(0.01)	0	(0.01)	0
Net income (in dollars per share)	0.38	0.09	0.63	0.03
Diluted:
Income from continuing operations (in dollars per share)	0.37	0.09	0.61	0.03
Loss from discontinued operations (in dollars per share)	(0.01)	0	(0.01)	0
Net income (in dollars per share)	$ 0.36	$ 0.09	$ 0.60	$ 0.03
Weighted average shares used in computing income (loss) per share:
Basic (in shares)	27,708	26,711	27,343	26,514
Diluted (in shares)	28,725	27,385	28,488	27,390
Cash dividends declared per share (in dollars per share)	$ 0.06	$ 0.06	$ 0.12	$ 0.12