Consolidated Balance Sheets (Parenthetical) - USD ($)	Dec. 31, 2015	Dec. 31, 2014
Statement of Financial Position [Abstract]
Allowances on accounts receivable	$ 191,285	$ 119,530
Accumulated depreciation on property and equipment	$ 17,947,675	$ 16,867,911
Series A redeemable convertible preferred stock, par value (in dollars per share)	$ 0.001	$ 0.001
Series A redeemable convertible preferred stock, shares authorized	2,000,000	2,000,000
Series A redeemable convertible preferred stock, shares issued	900,000	900,000
Series A redeemable convertible preferred stock, shares outstanding	900,000	900,000
Series A redeemable convertible preferred stock, redemption value	$ 9,000,000	$ 9,000,000
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized	100,000,000	100,000,000
Common stock, shares issued	57,194,817	56,360,222
Common stock, shares outstanding	41,666,747	40,924,313
Common Stock, held in treasury, shares	15,528,070	15,435,909