Consolidated Statements of Operations - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Statement [Abstract]
Sales	$ 292,013	$ 315,249	$ 311,633
Cost of sales	194,486	210,711	210,851
Gross profit	97,527	104,538	100,782
Selling, general and administrative expenses	79,647	81,271	81,045
Research & development	13,514	14,140	13,904
Restructuring charges	661	3,558	0
Impairment charges	0	0	5,766
Other expense, net	310	632	514
Income (loss) from operations	3,395	4,937	(447)
Interest expense	555	655	737
Interest income	(227)	(156)	(59)
Income (loss) from continuing operations before income taxes	3,067	4,438	(1,125)
Income taxes	1,843	1,828	1,233
Net income (loss) from continuing operations	1,224	2,610	(2,358)
Gain from disposal of discontinued operation, net of tax	0	0	218
Net income (loss)	$ 1,224	$ 2,610	$ (2,140)
Basic earnings (loss) per share:
Continuing operations (in dollars per share)	$ 0.10	$ 0.20	$ (0.19)
Disposal of discontinued operation (in dollars per share)	0.00	0.00	0.02
Basic (loss) earnings per share (in dollars per share)	0.10	0.20	(0.17)
Diluted (loss) earnings per share:
Continuing operations (in dollars per share)	0.09	0.20	(0.19)
Disposal of discontinued operation (in dollars per share)	0.00	0.00	0.02
Diluted (loss) earnings per share (in dollars per share)	0.09	0.20	(0.17)
Cash dividends declared per share: (in dollars per share)	$ 0.08	$ 0.08	$ 0.08