CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) (USD $)	Mar. 31, 2013	Dec. 31, 2012
Statement of Financial Position [Abstract]
Allowances on accounts receivable	$ 397,797	$ 940,101
Accumulated depreciation on Property and equipment	$ 16,656,470	$ 16,131,570
Preferred stock, par value	$ 0.001	$ 0.001
Preferred stock, shares authorized	2,000,000	2,000,000
Common stock, par value	$ 0.001	$ 0.001
Common stock, shares authorized	100,000,000	100,000,000
Common stock, shares issued	55,974,542	55,615,972
Common stock, shares outstanding	47,969,307	47,610,737
Common Stock held in treasury, shares	8,005,235	8,005,235