STATEMENTS OF INCOME AND COMPREHENSIVE INCOME (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Revenues	$ 29,204,818	$ 26,870,297	$ 25,223,534
Cost of revenues	14,066,652	11,476,263	10,971,886
Gross profit	15,138,166	15,394,034	14,251,648
Operating Expenses:
General & administrative	4,474,654	4,157,597	3,946,844
Marketing & selling	4,625,375	4,704,970	4,543,598
Research & development	1,348,496	825,102	825,518
Total Operating Expenses	10,448,525	9,687,669	9,315,960
Operating income	4,689,641	5,706,365	4,935,688
Other income (expense)	(56,576)	92,273	1,889
Net income before provision for income taxes	4,633,065	5,798,638	4,937,577
Provision for income taxes	1,426,984	1,993,428	1,957,948
Net income and comprehensive income	$ 3,206,081	$ 3,805,210	$ 2,979,629
Basic net income per share (in dollars per share)	$ 0.60	$ 0.72	$ 0.57
Diluted net income per share (in dollars per share)	$ 0.60	$ 0.72	$ 0.57
Dividends declared per share (in dollars per share)	$ 0.60	$ 0.60	$ 0.60
Weighted average common shares outstanding, basic (in shares)	5,355,367	5,299,060	5,260,320
Weighted average common shares outstanding, diluted (in shares)	5,376,998	5,315,463	5,272,542