Statements Of Comprehensive Income (Loss) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Statements Of Comprehensive Income (Loss) [Abstract]
Net Sales	$ 7,495	$ 7,840
Cost of Goods Sold	3,448	3,541
Gross Profit	4,047	4,299
Operating Expenses
Selling and marketing	1,634	1,469
General and administrative	1,745	1,608
Research and development	813	812
Total Operating Expenses	4,192	3,889
Operating Income (Loss)	(145)	410
Non-operating Income (Expense)
Interest expense	(1)	0
Interest income	120	38
Other income	8	10
Total Non-operating Income, Net	127	48
Income (Loss) before Income Taxes	(18)	458
Income Taxes Expense (Benefit)	(8)	163
Net Income (Loss)	(10)	295
Other Comprehensive Income
Change in unrealized value of available-for-sale securities, net of income tax	13	41
Other Comprehensive Income	13	41
Net Comprehensive Income	$ 3	$ 336
Basic
Net income (loss) per share	$ 0.00	$ 0.09
Weighted average shares	3,395,521	3,395,521
Diluted
Net income (loss) per share	$ 0.00	$ 0.09
Weighted average shares	3,395,521	3,401,017