Condensed Consolidated Statements of Operations (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Income Statement [Abstract]
Revenues	$ 8,948	$ 11,847	$ 19,103	$ 24,638
Costs and expenses:
Cost of sales	5,050	8,125	11,191	15,891
Selling, general and administrative	4,455	4,763	8,913	9,684
Restructuring charge	30	0	625	0
Research and development	205	261	471	549
Asset Impairment Charges	51	317	51	317
Costs and expenses:	9,791	13,466	21,251	26,441
Operating loss from continuing operations	(843)	(1,619)	(2,148)	(1,803)
Interest expense	(3)	0	(4)	0
Interest income	9	0	11	2
Other expense	(97)	(59)	(72)	(67)
Loss from continuing operations before income taxes	(934)	(1,678)	(2,213)	(1,868)
Income tax expense	(2)	(1)	(2)	(2)
Net loss from continuing operations	(936)	(1,679)	(2,215)	(1,870)
Loss from discontinued operations (net of income tax benefit of $0 in 2019 and 2018)	(9)	(74)	(19)	(99)
Net loss	$ (945)	$ (1,753)	$ (2,234)	$ (1,969)
Basic
Continuing operations (in dollars per share)	$ (0.04)	$ (0.07)	$ (0.09)	$ (0.08)
Discontinued operations (in dollars per share)	0.00	0.00	0.00	0.00
Basic net loss per common share (in dollars per share)	(0.04)	(0.07)	(0.09)	(0.08)
Diluted
Continuing operations (in dollars per share)	(0.04)	(0.07)	(0.09)	(0.08)
Discontinued operations (in dollars per share)	0.00	0.00	0.00	0.00
Diluted net loss per common share (in dollars per share)	$ (0.04)	$ (0.07)	$ (0.09)	$ (0.08)
Weighted-average number of common shares outstanding:
Basic (in shares)	24,187,000	24,170,000	24,182,000	24,158,000
Diluted (in shares)	24,187,000	24,170,000	24,182,000	24,158,000