Consolidated Statements of Operations - USD ($) shares in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Statement [Abstract]
Revenues	$ 30,467,000	$ 56,535,000	$ 45,166,000
Costs and expenses:
Cost of sales	19,637,000	36,471,000	27,144,000
Selling, general and administrative	17,191,000	18,564,000	20,933,000
Restructuring charge	625,000	0	119,000
Research and development	1,127,000	1,073,000	1,070,000
Intangible assets abandonment and building impairment	127,000	317,000	2,965,000
Total Costs and Expenses	38,707,000	56,425,000	52,231,000
Operating income (loss) from continuing operations	(8,240,000)	110,000	(7,065,000)
Interest income	41,000	6,000	10,000
Foreign exchange gain	370,000	0	0
Other expense	(8,000)	2,000	(60,000)
Income (loss) from continuing operations before income taxes	(7,837,000)	118,000	(7,115,000)
Income tax benefit (expense)	(14,000)	(33,000)	580,000
Net income (loss) from continuing operations	(7,851,000)	85,000	(6,535,000)
Loss from discontinued operations (net of income tax benefit of $0 in 2018, 2017 and 2016)	(1,000)	(113,000)	(3,914,000)
Net loss	$ (7,852,000)	$ (28,000)	$ (10,449,000)
Basic net loss per common share
Continuing operations (in dollars per share)	$ (0.32)	$ 0.00	$ (0.28)
Discontinued operations (in dollars per share)	0.00	0.00	(0.16)
Basic (in dollars per share)	(0.32)	0.00	(0.44)
Diluted net loss per common share
Continuing operations (in dollars per share)	(0.32)	0.00	(0.28)
Discontinued operations (in dollars per share)	0.00	0.00	(0.16)
Diluted (in dollars per share)	$ (0.32)	$ 0.00	$ (0.44)
Weighted-average number of common shares outstanding:
Basic (in shares)	24,202	24,164	23,872
Diluted (in shares)	24,202	24,164	23,872