Consolidated Statements of Operations - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Income Statement [Abstract]
Revenue	$ 3,526	$ 3,878
Cost of goods sold	2,444	3,862
Gross profit (loss)	1,082	16
Operating expenses:
General and administrative	2,548	2,250
Sales and marketing	361	376
Research and development		122
(Gain) loss on sale or disposal of assets	(577)	(3,367)
Income (loss) from operations	(1,250)	635
Other income:
Interest income	460	361
Realized gain (loss) on marketable securities	(165)
Unrealized gain (loss) on marketable securities	(171)
Realized gain (loss) on foreign currency translation	1	(9)
Total other income	125	352
Income (loss) before income taxes	(1,125)	987
Income tax expense	(22)	(24)
Net income (loss)	$ (1,147)	$ 963
Net income (loss) per common share
Basic	$ (0.42)	$ 0.35
Diluted	$ (0.42)	$ 0.35
Weighted average common shares outstanding used in computing net income (loss) per common share
Basic	2,707,811	2,729,548
Diluted	2,707,811	2,734,721