Condensed Consolidated Statements Of Operations And Comprehensive Income (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Condensed Consolidated Statements Of Operations And Comprehensive Income [Abstract]
Net sales	$ 1,642	$ 1,517
Cost of goods sold	706	625
Gross profit	936	892
Operating expenses:
Selling and marketing	410	346
General and administrative	277	253
Research and development	127	101
Total operating expenses	814	700
Operating income	122	192
Non-operating income:
Interest income	1	3
Other income	3	2
Total non-operating income	4	5
Income from continuing operations before income taxes	126	197
Income taxes	48	69
Income before discontinued operations	78	128
Loss from discontinued operations, net of income tax	0	(34)
Net income	78	94
Other comprehensive income:
Change in unrealized value of investments, net of income tax	393	642
Total comprehensive income	$ 471	$ 736
Net income per share data:
Net income per share continuing operations	$ 0.02	$ 0.04
Net loss per share discontinued operations	$ 0.00	$ (0.01)
Net income per share	$ 0.02	$ 0.03
Weighted average shares	3,390,719	3,383,767
Diluted
Net income per share continuing operations	$ 0.02	$ 0.04
Net loss per share discontinued operations	$ 0.00	$ (0.01)
Net income per share	$ 0.02	$ 0.03
Weighted average shares	3,407,699	3,405,247
Dividends paid per share	$ 0.04	$ 0.04