Net Loss per Share Attributable to Common Stockholders (Tables)

3 Months Ended

Mar. 31, 2015

Earnings Per Share [Abstract]

Common Equivalent Shares Excluded from Computation of Diluted Net Loss

The following common equivalent shares were excluded from the computation of diluted net loss per share attributable to common stockholders for the periods presented because including them would have been anti-dilutive:

	Three Months Ended March 31,
	2015		2014
Stock options to purchase common stock		4,787,869		4,202,821
Common stock warrants		1,500		13,873
Restricted stock units		171,787		—
Performance stock units		140,000		—