Net Loss Per Share Attributable to Common Stockholders (Tables)

12 Months Ended

Dec. 31, 2012

Earnings Per Share [Abstract]

Schedule of potential common shares outstanding that were excluded from the computation of diluted net loss per share attributable to common stockholders

The following table presents the potential common shares outstanding that 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 (in thousands):

	Year Ended December 31,
	2012	2011	2010
Convertible preferred stock	—	25,171	25,171
Stock options to purchase common stock	8,169	6,256	5,802
Convertible notes	—	2,328	—
Shares issuable pursuant to ESPP	5	—	—
Unvested restricted stock units	248	—	—
Common stock warrants	331	143	11
Convertible preferred stock warrants	—	215	141
Total	8,753	34,113	31,125