Condensed Consolidated Statements of Operations - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Income Statement [Abstract]
Revenues	$ 3,778	$ 10,155
Costs and expenses:
Cost of sales	2,251	6,141
Selling, general and administrative	3,886	4,458
Restructuring charge	0	595
Research and development	324	266
Costs and expenses:	6,461	11,460
Operating loss from continuing operations	(2,683)	(1,305)
Interest expense	(3)	(1)
Interest income	11	2
Other income	226	25
Loss from continuing operations before income taxes	(2,449)	(1,279)
Income tax expense	(118)	0
Net loss from continuing operations	(2,567)	(1,279)
Loss from discontinued operations (net of income tax benefit of $0 in 2020 and 2019)	0	(10)
Net loss	$ (2,567)	$ (1,289)
Basic
Continuing operations (in dollars per share)	$ (0.10)	$ (0.05)
Discontinued operations (in dollars per share)	0.00	0.00
Basic net loss per common share (in dollars per share)	(0.10)	(0.05)
Diluted
Continuing operations (in dollars per share)	(0.10)	(0.05)
Discontinued operations (in dollars per share)	0.00	0.00
Diluted net loss per common share (in dollars per share)	$ (0.10)	$ (0.05)
Weighted-average number of common shares outstanding:
Basic (in shares)	24,597,000	24,177,000
Diluted (in shares)	24,597,000	24,177,000