Condensed Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Income Statement [Abstract]
Revenues	$ 15,175	$ 18,683	$ 32,997	$ 33,786
Costs and expenses:
Cost of sales	9,595	11,547	21,369	19,984
Selling, general and administrative	6,760	8,400	14,239	16,603
Research and development	1,122	982	2,280	1,854
Costs and expenses:	17,477	20,929	37,888	38,441
Operating (loss)	(2,302)	(2,246)	(4,891)	(4,655)
Interest expense	0	(3)	0	(30)
Interest income	6	7	16	14
Other expense	(221)	(65)	(484)	(161)
(Loss) before income taxes	(2,517)	(2,307)	(5,359)	(4,832)
Income tax benefit	(111)	936	94	1,807
Net (loss)	$ (2,628)	$ (1,371)	$ (5,265)	$ (3,025)
Net (loss) per common share:
Basic (in dollars per share)	$ (0.11)	$ (0.06)	$ (0.23)	$ (0.13)
Diluted (in dollars per share)	$ (0.11)	$ (0.06)	$ (0.23)	$ (0.13)
Weighted-average number of common shares outstanding:
Basic (in shares)	23,381	23,140	23,283	23,034
Diluted (in shares)	23,381	23,140	23,283	23,034