Condensed Consolidated Statements of Operations (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Income Statement [Abstract]
Revenues	$ 10,155	$ 12,791
Costs and expenses:
Cost of sales	6,141	7,766
Selling, general and administrative	4,458	4,921
Restructuring charge	595	0
Research and development	266	288
Costs and expenses:	11,460	12,975
Operating loss from continuing operations	(1,305)	(184)
Interest expense	(1)	0
Interest income	2	2
Other expense	25	(8)
Loss from continuing operations before income taxes	(1,279)	(190)
Income tax expense	0	(1)
Net loss from continuing operations	(1,279)	(191)
Loss from discontinued operations (net of income tax benefit of $0 in 2019 and 2018)	(10)	(25)
Net loss	$ (1,289)	$ (216)
Basic
Continuing operations (in dollars per share)	$ (0.05)	$ (0.01)
Discontinued operations (in dollars per share)	0.00	0.00
Basic net loss per common share (in dollars per share)	(0.05)	(0.01)
Diluted
Continuing operations (in dollars per share)	(0.05)	(0.01)
Discontinued operations (in dollars per share)	0.00	0.00
Diluted net loss per common share (in dollars per share)	$ (0.05)	$ (0.01)
Weighted-average number of common shares outstanding:
Basic (in shares)	24,177,000	24,146,000
Diluted (in shares)	24,177,000	24,146,000