STATEMENTS OF INCOME (USD $)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Revenues	$ 24,089,608	$ 20,108,862	$ 16,954,994
Cost of revenues	9,616,985	8,067,229	7,345,016
Gross profit	14,472,623	12,041,633	9,609,978
Operating expenses:
General and administrative	3,948,706	4,195,998	3,596,774
Marketing and selling	4,116,059	2,949,739	2,961,477
Research and development	607,408	481,433	467,435
Total operating expenses	8,672,173	7,627,170	7,025,686
Income from operations	5,800,450	4,414,463	2,584,292
Interest income	5,346	23,091	45,320
Income before taxes	5,805,796	4,437,554	2,629,612
Provision for income taxes	2,316,513	1,823,834	1,102,317
Net income	$ 3,489,283	$ 2,613,720	$ 1,527,295
Basic net income per share (in dollars per share)	$ 0.67	$ 0.50	$ 0.29
Diluted income per share (in dollars per share)	$ 0.67	$ 0.50	$ 0.29
Dividends declared per share (in dollars per share)	$ 0.48	$ 0.48	$ 0.53
Weighted average common shares outstanding, basic (in shares)	5,229,646	5,207,244	5,193,329
Weighted average common shares outstanding, diluted (in shares)	5,235,940	5,226,454	5,204,767