Net Loss Per Share (Tables)

6 Months Ended

Jun. 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:

	Three Months Ended June 30,						Six Months Ended June 30,
	2015			2014			2015			2014
Numerator:
Net loss	$	(6,452,342	)	$	(3,684,826	)	$	(10,540,477	)	$	(6,512,416	)
Accretion of stock issuance costs		(10,969	)		(186,206	)		(35,046	)		(208,687	)
Accretion of discount on Series E warrants		(40,146	)		(85,717	)		(127,616	)		(137,094	)
Series E and D, preferred stock dividends		(367,350	)		(828,125	)		(1,165,932	)		(1,568,762	)
Net loss attributable to common stockholders	$	(6,870,807	)	$	(4,784,874	)	$	(11,869,071	)	$	(8,426,959	)
Denominator:
Weighted-average common shares outstanding    -basic and diluted		3,973,055			96,440			2,163,295			96,426

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

The following outstanding options, warrants and 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:

	Six Months Ended June 30,
	2015		2014
Options to purchase common stock		610,090		553,622
Convertible preferred stock (as converted)		—		2,353,163
Convertible preferred stock warrants (as converted)		—		27,534
Common stock warrant		170,587		931