Net Loss Per Share (Tables)

9 Months Ended

Sep. 30, 2014

Earnings Per Share Attributable to Common Stockholders

Computation of basic and diluted net loss per share attributable to common stockholders

	Three Months Ended				Nine Months Ended
	September 30,				September 30,
	2014		2013		2014		2013
Net loss	$	(13,640)	$	(4,611)	$	(38,595)	$	(17,436)
Weighted-average common shares outstanding		76,880		59,799		68,315		58,096
Net loss per share - basic and diluted	$	(0.18)	$	(0.08)	$	(0.56)	$	(0.30)

Anti-dilutive shares excluded from the calculation of diluted net loss per share

	September 30,
	2014	2013
Options to purchase common stock	26,428	16,475
Common stock warrants	3,942	5,264
Unvested restricted stock awards	720	72
Contingently redeemable shares	—	112
Total shares excluded from net loss per share	31,090	21,923