Net Loss per Share Attributable to Common Stockholders (Tables)

9 Months Ended

Sep. 30, 2014

Equity [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 September 30,				Nine Months Ended September 30,
	2014		2013		2014		2013
Stock options to purchase common stock		4,159,895		3,780,358		4,159,895		3,780,358
Common stock warrants		6,240		82,575		6,240		82,575