Loss Per Share of Common Stock (EPS) (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Numerator:
Net loss	$ (6,746,601)	$ (11,873,047)	$ (17,811,871)	$ (24,556,029)
Less: income from change in fair value of warrant liability		(125,557)		(158,180)
Numerator for diluted net loss per common share	$ (6,746,601)	$ (11,998,604)	$ (17,811,871)	$ (24,714,209)
Basic weighted average common shares outstanding (in shares)	24,769,083	23,332,096	24,769,083	23,074,550
Dilutive common shares from assumed warrant exercises (in shares)		38,239		41,703
Diluted weighted average shares of common stock outstanding (in shares)	24,769,083	23,370,335	24,769,083	23,116,253
Diluted net loss per share of common stock (in dollars per share)	$ (0.27)	$ (0.51)	$ (0.72)	$ (1.07)