Statements Of Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Statements Of Comprehensive Loss [Abstract]
Net sales	$ 1,716	$ 1,670
Cost of goods sold	800	771
Gross profit	916	899
Operating expenses
Selling and marketing	435	377
General and administrative	532	444
Research and development	230	221
Total operating expenses	1,197	1,042
Operating loss	(281)	(143)
Non-operating income
Interest income	23	8
Other income	2	3
Total non-operating income	25	11
Loss before income tax benefit	(256)	(132)
Benefit from income taxes	(54)	(48)
Net loss	(202)	(84)
Other comprehensive income (loss)
Change in unrealized value of available-for-sale securities, net of income tax	(1)	0
Other comprehensive income (loss)	(1)	0
Net comprehensive loss	$ (203)	$ (84)
Basic
Net loss per share	$ (0.06)	$ (0.02)
Weighted average shares	3,395,521	3,395,521
Diluted
Net loss per share	$ (0.06)	$ (0.02)
Weighted average shares	3,395,521	3,395,521