Loss Per Share of Common Stock (EPS) (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Numerator:
Net loss	$ (8,634,519)	$ (10,895,958)	$ (26,446,390)	$ (35,451,987)
Less: income from change in fair value of warrant liability		(26,358)		(184,538)
Numerator for diluted net loss per common share	$ (8,634,519)	$ (10,922,316)	$ (26,446,390)	$ (35,636,525)
Basic weighted average common shares outstanding (in shares)	24,769,083	23,830,978	24,769,083	23,329,464
Dilutive common shares from assumed warrant exercises (in shares)		33,953		39,878
Diluted weighted average shares of common stock outstanding (in shares)	24,769,083	23,864,931	24,769,083	23,369,342
Diluted net loss per share of common stock (in dollars per share)	$ (0.35)	$ (0.46)	$ (1.07)	$ (1.52)