Consolidated Statements Of Operations And Comprehensive Income (Loss) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Consolidated Statements Of Operations And Comprehensive Income (Loss) [Abstract]
Net sales	$ 1,571	$ 1,795	$ 3,105	$ 3,437
Cost of goods sold	673	787	1,315	1,493
Gross profit	898	1,008	1,790	1,944
Operating expenses:
Selling and marketing	390	383	785	793
General and administrative	284	248	582	525
Research and development	112	101	230	228
Total operating expenses	786	732	1,597	1,546
Operating income	112	276	193	398
Non-operating income:
Gain on sale of available-for-sale securities	298	0	401	0
Interest income	0	3	2	4
Other income	5	3	8	6
Total non-operating income	303	6	411	10
Income before income taxes	415	282	604	408
Income taxes	145	99	168	147
Net income	270	183	436	261
Other comprehensive income (loss):
Change in unrealized value of available-for-sale securities, net of income tax	33	(508)	(199)	(115)
Reclassification of gains included in net income	(298)	0	(401)	0
Net change in other comprehensive loss	(265)	(508)	(600)	(115)
Total comprehensive income (loss)	$ 5	$ (325)	$ (164)	$ 146
Basic
Net income per share	$ 0.07	$ 0.05	$ 0.12	$ 0.07
Weighted average shares	3,393,736	3,390,785	3,393,696	3,390,752
Diluted
Net income per share	$ 0.07	$ 0.05	$ 0.12	$ 0.07
Weighted average shares	3,415,716	3,407,765	3,415,676	3,407,732
Dividends paid per common share	$ 0.04	$ 0.04	$ 0.08	$ 0.08