Basis of Presentation and Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2015

Accounting Policies [Abstract]

Schedule of Antidilutive Securities Excluded from the Calculation of Basic and Diluted Loss Per Share

Shares used in calculating diluted net loss per common share exclude as anti-dilutive the following share equivalents:

	December 31,
	2015	2014	2013
Options to purchase Common Stock	6,948,630	4,913,472	4,287,545
Warrants to purchase Common stock	4,565,947	5,251,660	6,233,483
Series A Convertible Preferred Stock	63,125	63,125	63,125
	11,577,702	10,228,257	10,584,153

Summary of the Company’s Diluted Net Loss Per Share

The following table summarizes the Company’s diluted net loss per share:

	December 31,
	2015			2014			2013
Numerator:
Net loss attributable to common stockholders	$	(27,495,334	)	$	(14,348,499	)	$	(11,840,778	)
Adjustment for change in fair value of derivative instruments - warrants	(4,396,061		)	(2,422,337		)	—
Net loss used for diluted loss per share	$	(31,891,395	)	$	(16,770,836	)	$	(11,840,778	)
Denominator:
Weighted-average shares used to compute basic net loss per share	26,201,713			18,904,280			16,978,212
Adjustments to reflect assumed exercise of warrants	250,452			166,832			—
Weighted-average shares used to compute diluted net loss per share	26,452,165			19,071,112			16,978,212
Net loss per share diluted	$	(1.21	)	$	(0.88	)	$	(0.70	)