Selected Quarterly Financial Data (unaudited) (Details) (USD $)	3 Months Ended								12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Selected quarterly financial data (unaudited)
Revenues	$ 7,130,639	$ 6,970,263	$ 7,761,474	$ 6,982,137	$ 11,034,515	$ 9,534,138	$ 8,094,126	$ 7,476,236	$ 28,844,513	$ 36,139,015	$ 26,050,792
Cost of net revenues	4,331,166	632,209	762,497	751,460	779,581	503,080	382,060	372,928
Loss from operations	(12,909,486)	(6,073,772)	(6,446,839)	(8,334,585)	(4,731,724)	(1,843,386)	(2,058,696)	(2,256,386)	(33,764,682)	(10,890,192)	(4,034,193)
Net loss	(13,019,811)	(6,108,492)	(6,521,155)	(8,313,090)	(4,863,417)	(1,845,551)	(1,828,081)	(2,257,687)	(33,962,548)	(10,794,736)	(4,122,817)
Net loss per common share - basic and diluted (in dollars per share)	$ (0.13)	$ (0.06)	$ (0.07)	$ (0.09)	$ (0.05)	$ (0.02)	$ (0.02)	$ (0.03)	$ (0.35)	$ (0.13)	$ (0.05)
Reclassification of historical amortization of developed technology					237,444	15,956
Developed technology impairment loss	$ 3,423,100