Consolidated Statements Of Operations And Comprehensive Income (Loss) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Consolidated Statements Of Operations And Comprehensive Income (Loss) [Abstract]
Net sales	$ 1,534	$ 1,642
Cost of goods sold	642	706
Gross profit	892	936
Operating expenses:
Selling and marketing	395	410
General and administrative	298	277
Research and development	118	127
Total operating expenses	811	814
Operating income	81	122
Non-operating income:
Gain on sale of available-for-sale securities	103	0
Interest income	2	1
Other income	3	3
Total non-operating income	108	4
Income before income taxes	189	126
Income taxes	23	48
Net income	166	78
Other comprehensive income (loss):
Change in unrealized value of available-for-sale securities, net of income tax	(232)	393
Reclassification adjustment of gains included in net income	(103)	0
Net change in other comprehensive income (loss)	(335)	393
Total comprehensive income (loss)	$ (169)	$ 471
Basic
Net income per share	$ 0.04	$ 0.02
Weighted average shares	3,393,655	3,390,719
Diluted
Net income per share	$ 0.04	$ 0.02
Weighted average shares	3,415,635	3,407,699
Dividends paid per common share	$ 0.04	$ 0.04