Net Loss Per Share (Tables)

9 Months Ended

Sep. 30, 2015

Earnings Per Share [Abstract]

Reconciliation of Numerator and Denominator Used in Computing Basic and Diluted Net Loss per Share

The following table provides a reconciliation of the numerator and denominator used in computing basic and diluted net loss per share for the periods presented:

	Three Months Ended September 30,						Nine Months Ended September 30,
	2015			2014			2015			2014
Numerator:
Net loss	$	(5,157,663	)	$	(3,307,329	)	$	(15,698,139	)	$	(9,819,746	)
Accretion of stock issuance costs		—			(19,488	)		(35,046	)		(71,175	)
Accretion of discount on Series E warrants		—			(94,893	)		(127,616	)		(251,893	)
Series E and D, Convertible Preferred Stock    dividends		—			(837,225	)		(1,165,932	)		(2,405,987	)
Net loss attributable to common stockholders	$	(5,157,663	)	$	(4,258,935	)	$	(17,026,733	)	$	(12,548,801	)
Denominator:
Weighted-average common shares outstanding    -basic and diluted		6,829,687			96,486			3,735,852			96,446
Net loss per share attributable to common stockholders,    basic and diluted	$	(0.76	)	$	(44.14	)	$	(4.56	)	$	(130.11	)

Outstanding Options, Warrants and Convertible Preferred Stock Excluded from Computation of Diluted Net Loss per Share

The following outstanding options, warrants and Convertible Preferred Stock were excluded from the computation of diluted net loss per share for the periods presented because their effect would have been anti-dilutive:

	Three and Nine Months Ended September 30,
	2015		2014
Options to purchase common stock		590,139		542,435
Restricted stock units		27,500		—
Convertible Preferred Stock (as converted)		—		2,353,166
Convertible Preferred Stock warrants (as converted)		—		51,863
Common stock warrant		170,587		931