Statements Of Comprehensive Income (Loss) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Statements Of Comprehensive Income (Loss) [Abstract]
Net sales	$ 8,258	$ 7,495
Cost of goods sold	3,892	3,448
Gross profit	4,366	4,047
Operating expenses
Selling and marketing	1,929	1,634
General and administrative	1,657	1,745
Research and development	811	813
Total operating expenses	4,397	4,192
Operating loss	(31)	(145)
Non-operating income (expense)
Interest expense	(2)	(1)
Interest income	209	120
Other income	10	8
Total non-operating income, net	217	127
Income (loss) before income taxes	186	(18)
Income tax benefit	(1)	(8)
Net income (loss)	187	(10)
Other comprehensive income (loss)
Change in unrealized value of available-for-sale securities, net of income tax	(32)	13
Other comprehensive income (loss)	(32)	13
Net Comprehensive Income	$ 155	$ 3
Basic
Net income per share	$ 0.06	$ 0.00
Weighted average shares	3,395,521	3,395,521
Diluted
Net income per share	$ 0.06	$ 0.00
Weighted average shares	3,398,035	3,395,521