Condensed Consolidated Statements Of Operations (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Condensed Consolidated Statements Of Operations [Abstract]
Net sales	$ 1,567	$ 1,632	$ 5,004	$ 4,692
Cost of goods sold	696	694	2,189	1,977
Gross profit	871	938	2,815	2,715
Operating expenses:
Selling and marketing	305	345	1,098	1,040
General and administrative	244	242	769	721
Research and development	105	111	333	330
Total operating expenses	654	698	2,200	2,091
Operating income	217	240	615	624
Non-operating income (expense):
Gain on disposal of investment securities	0	0	0	1
Interest income	1	1	5	5
Loss on disposal of fixed assets	0	(18)	0	(18)
Other income	3	2	9	5
Total non-operating income (expense)	4	(15)	14	(7)
Income from continuing operations before income taxes	221	225	629	617
Income taxes	77	90	224	246
Income before discontinued operations	144	135	405	371
Loss from discontinued operations, net of income tax benefit	0	(17)	0	(41)
Net income	144	118	405	330
Other comprehensive income (loss):
Change in unrealized value of investments, net of income tax	378	(863)	263	(301)
Total comprehensive income (loss)	$ 522	$ (745)	$ 668	$ 29
Net income (loss) per share data:
Net income per share continuing operations	$ 0.04	$ 0.04	$ 0.11	$ 0.11
Net loss per share discontinued operations	$ 0.00	$ (0.01)	$ 0.00	$ (0.01)
Net income per share	$ 0.04	$ 0.03	$ 0.11	$ 0.10
Weighted average shares	3,391,900	3,389,506	3,391,126	3,387,192
Diluted
Net income per share continuing operations	$ 0.04	$ 0.04	$ 0.11	$ 0.11
Net loss per share discontinued operations	$ 0.00	$ (0.01)	$ 0.00	$ (0.01)
Net income per share	$ 0.04	$ 0.03	$ 0.11	$ 0.10
Weighted average shares	3,417,032	3,406,486	3,410,843	3,405,738
Dividends paid per share	$ 0.04	$ 0.04	$ 0.12	$ 0.12