Loss Per Share of Common Stock (Tables)

3 Months Ended

Mar. 31, 2015

Loss Per Share of Common Stock

Schedule of computation of diluted net loss per share

	Three Months Ended March 31,
	2014		2015
Numerator:
Net loss	$	(5,334,067)	$	(12,682,982)
Less: income from change in fair value of warrant liability		(285,021)		(32,623)
Numerator for diluted net loss per common share	$	(5,619,088)	$	(12,715,605)
Denominator:
Basic weighted average common shares outstanding		22,249,474		22,814,142
Dilutive common shares from assumed warrant exercises		71,999		43,872
Diluted weighted average shares of common stock outstanding		22,321,473		22,858,014
Diluted net loss per share of common stock	$	(0.25)	$	(0.56)

Schedule of potentially dilutive securities outstanding that have been excluded from the computation of diluted weighted average shares outstanding, as they would be antidilutive

	March 31,
	2014	2015
Warrants	2,696	23,747
Stock options	3,166,976	3,650,605
Unvested restricted stock	48,408	450,000
Common shares issuable upon conversion of the 8% Notes	—	7,137,031
	3,218,080	11,261,383