Condensed Consolidated Statements of Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Income Statement [Abstract]
Sales, net	$ 13,302	$ 11,831	$ 38,704	$ 29,973
Expenses
Cost of products	7,839	8,014	22,519	19,425
Selling, general and administrative	4,585	3,660	13,229	10,624
Total expenses	12,424	11,674	35,748	30,049
Operating income (loss)	878	157	2,956	(76)
Other (expense) income:
Interest income	28	14	63	32
(Loss) gain on investment in securities	(191)	670	(1,392)	1,287
Gain (loss) on disposal of property, plant and equipment	0	10	0	(94)
Other (expense) income	(48)	1	(274)	(146)
Total other (expense) income	(211)	695	(1,603)	1,079
Income before income taxes	667	852	1,353	1,003
Income tax expense	(17)	(252)	(200)	(353)
Net income	$ 650	$ 600	$ 1,153	$ 650
Net earnings per share-basic	$ 0.05	$ 0.04	$ 0.09	$ 0.05
Net earnings per share-diluted	$ 0.05	$ 0.04	$ 0.09	$ 0.05
Weighted average shares outstanding-basic	13,479,759	13,665,976	13,538,116	13,602,207
Weighted average shares outstanding-diluted	13,501,587	13,688,297	13,563,990	13,704,884