Loss Per Share (Tables)

6 Months Ended

Jun. 30, 2015

Dilutive Shares Which Could Exist Pursuant to Exercise of Outstanding Stock Instruments and Which were not Included in Calculation

Dilutive shares which could exist pursuant to the exercise of outstanding stock instruments and which were not included in the calculation because their affect would have been anti-dilutive are as follows:

	June 30, 2015 (shares)		June 30, 2014 (shares)
Warrants to purchase shares of common stock		5,370,995		5,450,995
Options to purchase shares of common stock		3,192,325		3,311,029
Unvested shares of restricted common stock		337,935		—
Shares of common stock issuable upon conversion of preferred stock		2,527,103		2,537,103
		11,428,358		11,299,127