Condensed Consolidated Statements of Operations - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Income Statement [Abstract]
Revenues	$ 12,791	$ 8,491
Costs and expenses:
Cost of sales	7,766	4,769
Selling, general and administrative	4,921	5,154
Restructuring charge	0	61
Research and development	288	284
Costs and expenses:	12,975	10,268
Operating loss from continuing operations	(184)	(1,777)
Interest income	2	3
Other expense	(8)	(2)
Loss from continuing operations before income taxes	(190)	(1,776)
Income tax expense	(1)	0
Net loss from continuing operations	(191)	(1,776)
Loss from discontinued operations (net of income tax benefit of $0 in 2018 and 2017)	(25)	(730)
Net loss	$ (216)	$ (2,506)
Basic
Continuing operations (in dollars per share)	$ (0.01)	$ (0.08)
Discontinued operations (in dollars per share)	0.00	(0.03)
Basic net loss per common share (in dollars per share)	(0.01)	(0.11)
Diluted
Continuing operations (in dollars per share)	(0.01)	(0.08)
Discontinued operations (in dollars per share)	0.00	(0.03)
Diluted net loss per common share (in dollars per share)	$ (0.01)	$ (0.11)
Weighted-average number of common shares outstanding:
Basic (in shares)	24,146,000	23,472,000
Diluted (in shares)	24,146,000	23,472,000