Condensed Consolidated Statements of Operations (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 25, 2016	Jun. 27, 2015	Jun. 25, 2016	Jun. 27, 2015
Net sales	$ 76,353	$ 75,211	$ 142,131	$ 138,658
Cost and expenses:
Cost of sales	49,669	49,509	96,006	92,811
Research and development	8,305	7,731	16,108	16,296
Selling, general and administrative	15,015	13,811	28,385	26,083
Cost and expenses	72,989	71,051	140,499	135,190
Income from operations	3,364	4,160	1,632	3,468
Interest and other, net	59	4	102	10
Income from continuing operations before taxes	3,423	4,164	1,734	3,478
Income tax provision	761	277	983	1,311
Income from continuing operations	2,662	3,887	751	2,167
Loss from discontinued operations	(55)	(3,959)	(55)	(4,979)
Net income (loss)	$ 2,607	$ (72)	$ 696	$ (2,812)
Basic:
Income from continuing operations (in dollars per share)	$ 0.10	$ 0.15	$ 0.03	$ 0.08
Loss from discontinued operations (in dollars per share)	0	(0.15)	0	(0.19)
Net income (loss) (in dollars per share)	0.10	0	0.03	(0.11)
Diluted:
Income from continuing operations (in dollars per share)	0.10	0.15	0.03	0.08
Loss from discontinued operations (in dollars per share)	0	(0.15)	0	(0.19)
Net income (loss) (in dollars per share)	$ 0.10	$ 0	$ 0.03	$ (0.11)
Weighted average shares used in computing loss per share:
Weighted average common shares (in shares)	26,711	26,059	26,514	25,905
Diluted (in shares)	27,358	26,722	27,350	26,620
Cash dividends declared per share (in dollars per share)	$ 0.06	$ 0.06	$ 0.12	$ 0.12