Condensed Consolidated Statements of Operations - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Income Statement [Abstract]
Revenues	$ 4,401	$ 8,948	$ 8,179	$ 19,103
Costs and expenses:
Cost of sales	3,799	5,050	6,050	11,191
Selling, general and administrative	2,755	4,455	6,641	8,913
Restructuring charge	0	30	0	625
Research and development	271	205	595	471
Intangible assets abandonment	0	51	0	51
Costs and expenses:	6,825	9,791	13,286	21,251
Operating loss from continuing operations	(2,424)	(843)	(5,107)	(2,148)
Interest expense	(3)	(3)	(6)	(4)
Interest income	2	9	13	11
Other income (expense), net	(88)	(97)	138	(72)
Loss from continuing operations before income taxes	(2,513)	(934)	(4,962)	(2,213)
Income tax expense	(31)	(2)	(149)	(2)
Net loss (income) from continuing operations	(2,544)	(936)	(5,111)	(2,215)
Loss from discontinued operations	0	(9)	0	(19)
Net loss	$ (2,544)	$ (945)	$ (5,111)	$ (2,234)
Basic
Continuing operations (in dollars per share)	$ (0.10)	$ (0.04)	$ (0.21)	$ (0.09)
Discontinued operations (in dollars per share)	0.00	0.00	0.00	0.00
Basic net loss per common share (in dollars per share)	(0.10)	(0.04)	(0.21)	(0.09)
Diluted
Continuing operations (in dollars per share)	(0.10)	(0.04)	(0.21)	(0.09)
Discontinued operations (in dollars per share)	0.00	0.00	0.00	0.00
Diluted net loss per common share (in dollars per share)	$ (0.10)	$ (0.04)	$ (0.21)	$ (0.09)
Weighted-average number of common shares outstanding:
Basic (in shares)	24,668,000	24,187,000	24,633,000	24,182,000
Diluted (in shares)	24,668,000	24,187,000	24,633,000	24,182,000