Net Loss Per Share Attributable to Common Stockholders (Tables)

6 Months Ended

Jun. 30, 2015

Net Loss Per Share Attributable to Common Stockholders

Schedule of outstanding potentially dilutive securities excluded from the calculation of diluted net loss per common share

	Six Months Ended June 30,
	2015	2014
Shares of common stock issuable upon conversion of preferred stock	—	2,010,596
Shares of common stock subject to outstanding options and restricted stock units	870,720	832,407
Warrants to purchase common stock	605,872	224,330
Total shares of common stock equivalents	1,476,592	3,067,333