Fair Value (Details 2) (Common stock warrant liability, USD $)	9 Months Ended
	Sep. 30, 2014
Common stock warrant liability
Reconciliations of the beginning and ending balances for liabilities measured at fair value on a recurring basis using significant unobservable inputs (i.e. Level 3)
Balance at the beginning of the period	$ 28,829,849
Change in fair value of common stock warrants	58,370,871
Issuance of common stock warrants	11,773,240
Exercise of common stock warrants	(83,444,573)
Balance at the end of the period	$ 15,529,387