Condensed Statements Of Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Statements Of Comprehensive Loss [Abstract]
Net sales	$ 2,008	$ 1,716
Cost of goods sold	941	800
Gross profit	1,067	916
Operating expenses
Selling and marketing	485	435
General and administrative	472	532
Research and development	196	230
Total operating expenses	1,153	1,197
Operating loss	(86)	(281)
Non-operating income
Interest income	44	23
Other income	2	2
Total non-operating income	46	25
Loss before income tax benefit	(40)	(256)
Benefit from income taxes	(9)	(54)
Net Loss	(31)	(202)
Other comprehensive income (loss)
Change in unrealized value of available-for-sale securities, net of income tax	1	(1)
Other Comprehensive Income (Loss)	1	(1)
Net comprehensive loss	$ (30)	$ (203)
Basic
Net loss per share	$ (0.01)	$ (0.06)
Weighted average shares	3,395,521	3,395,521
Diluted
Net loss per share	$ (0.01)	$ (0.06)
Weighted average shares	3,395,521	3,395,521