Condensed Consolidated Statements of Operations (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Income Statement [Abstract]
Sales, net	$ 11,831	$ 14,730	$ 29,973	$ 43,463
Expenses
Cost of products	8,014	10,099	19,425	29,412
Selling, general and administrative	3,660	3,549	10,624	10,110
Total expenses	11,674	13,648	30,049	39,522
Operating income (loss)	157	1,082	(76)	3,941
Other income (expense):
Interest income	14	2	32	4
Gain on available-for-sale securities	670	0	1,287	0
Gain (loss) on disposal of property, plant and equipment	10	0	(94)	0
Other (expense) income	1	0	(146)	7
Total other income	695	2	1,079	11
Income before income taxes	852	1,084	1,003	3,952
Income tax expense	(252)	(365)	(353)	(1,355)
Net income	$ 600	$ 719	$ 650	$ 2,597
Net earnings per share-basic	$ 0.04	$ 0.05	$ 0.05	$ 0.19
Net earnings per share-diluted	$ 0.04	$ 0.05	$ 0.05	$ 0.19
Weighted average shares outstanding-basic	13,665,976	13,741,170	13,602,207	13,735,361
Weighted average shares outstanding-diluted	13,688,297	13,836,304	13,704,884	13,825,256