Consolidated Statements of Operations - USD ($) shares in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Statement [Abstract]
Revenues	$ 56,535,000	$ 45,166,000	$ 55,161,000
Costs and expenses:
Cost of sales	36,471,000	27,144,000	36,367,000
Selling, general and administrative	18,564,000	20,933,000	25,564,000
Restructuring charge	0	119,000	1,428,000
Research and development	1,073,000	1,070,000	1,752,000
Intangible assets abandonment and building impairment	317,000	2,965,000	2,074,000
Total Costs and Expenses	56,425,000	52,231,000	67,185,000
Operating income (loss) from continuing operations	110,000	(7,065,000)	(12,024,000)
Interest income	6,000	10,000	25,000
Other expense	2,000	(60,000)	(925,000)
Income (loss) from continuing operations before income taxes	118,000	(7,115,000)	(12,924,000)
Income tax benefit (expense)	(33,000)	580,000	(1,664,000)
Net income (loss) from continuing operations	85,000	(6,535,000)	(14,588,000)
Loss from discontinued operations (net of income tax benefit of $0 in 2018, 2017 and 2016)	(113,000)	(3,914,000)	(2,800,000)
Net loss	$ (28,000)	$ (10,449,000)	$ (17,388,000)
Basic loss per common share
Continuing operations (in dollars per share)	$ 0.00	$ (0.28)	$ (0.62)
Discontinued operations (in dollars per share)	0.00	(0.16)	(0.12)
Basic (in dollars per share)	0.00	(0.44)	(0.01)
Diluted net loss per common share
Continuing operations (in dollars per share)	0.00	(0.28)	(0.62)
Discontinued operations (in dollars per share)	0.00	(0.16)	(0.12)
Diluted (in dollars per share)	$ 0.00	$ (0.44)	$ (0.74)
Weighted-average number of common shares outstanding:
Basic (in shares)	24,164	23,872	23,365
Diluted (in shares)	24,164	23,872	23,365