Condensed Consolidated Statements of Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Income Statement [Abstract]
Sales, net	$ 8,564	$ 10,889
Expenses
Cost of products	5,468	6,994
Selling, general and administrative	3,973	4,743
Total expenses	9,441	11,737
Operating loss	(877)	(848)
Other (expense) income:
Net interest (expense) income	(4)	9
Gain (loss) on investment in securities	205	(306)
Other expense	(18)	(47)
Total other income (expense)	183	(344)
Loss before income taxes	(694)	(1,192)
Income tax benefit	0	0
Net loss	$ (694)	$ (1,192)
Net loss per share-basic and diluted	$ (0.06)	$ (0.09)
Weighted average shares outstanding-basic and diluted	12,517,412	12,555,108