Condensed Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Income Statement [Abstract]
Revenues	$ 21,677	$ 21,482	$ 55,463	$ 60,333
Costs and expenses:
Cost of sales	13,829	11,582	33,813	34,069
Selling, general and administrative	7,122	8,080	23,725	25,783
Research and development	1,521	379	3,375	848
Costs and expenses:	22,472	20,041	60,913	60,700
Operating income (loss)	(795)	1,441	(5,450)	(367)
Interest expense	0	(33)	(30)	(96)
Interest income	3	6	17	23
Other expense	(100)	(285)	(261)	(354)
Income (loss) before income taxes	(892)	1,129	(5,724)	(794)
Income tax benefit	603	63	2,410	180
Net income (loss)	$ (289)	$ 1,192	$ (3,314)	$ (614)
Net income (loss) per common share:
Basic (in dollars per share)	$ (0.01)	$ 0.05	$ (0.14)	$ (0.03)
Diluted (in dollars per share)	$ (0.01)	$ 0.05	$ (0.14)	$ (0.03)
Weighted-average number of common shares outstanding:
Basic (in shares)	23,167	22,835	23,079	22,764
Diluted (in shares)	23,167	23,216	23,079	22,764