CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 28, 2015	Jun. 29, 2014	Jun. 28, 2015	Jun. 29, 2014
Income Statement [Abstract]
Net sales	$ 28,348	$ 27,009	$ 54,960	$ 51,122
Cost of sales	17,937	17,294	35,150	33,255
Gross profit	10,411	9,715	19,810	17,867
Operating expenses:
Research and development	800	790	1,699	1,589
Pension expense	502	925	1,004	1,850
Selling, general and administrative	5,884	5,250	11,374	10,240
Total operating expenses	7,186	6,965	14,077	13,679
Income from continuing operations before income taxes	3,225	2,750	5,733	4,188
Provision for income taxes	41	240	82	480
Income from continuing operations	3,184	2,510	5,651	3,708
Income (loss) from discontinued operations, net of tax	(146)	(213)	(309)	(357)
Net income	$ 3,038	$ 2,297	$ 5,342	$ 3,351
Earnings per common share - basic:
Income from continuing operations (in dollars per share)	$ 0.89	$ 0.77	$ 1.59	$ 1.14
Income (loss) from discontinued operations (in dollars per share)	(0.04)	(0.07)	(0.09)	(0.11)
Net income per common share (in dollars per share)	0.85	0.70	1.50	1.03
Earnings per common share - diluted:
Income from continuing operations (in dollars per share)	0.87	0.74	1.54	1.10
Income (loss) from discontinued operations (in dollars per share)	(0.04)	(0.06)	(0.09)	(0.11)
Net income per common share (in dollars per share)	$ 0.83	$ 0.68	$ 1.45	$ 0.99
Weighted average shares outstanding:
Basic (in shares)	3,566	3,267	3,558	3,265
Diluted (in shares)	3,679	3,372	3,678	3,375