Net Loss Per Share (Tables)
 3 Months Ended
Mar. 31, 2015
Earnings Per Share [Abstract]  
Basic and Diluted Net Income (Loss) per Share Attributable to Common Stockholders
The following table sets forth the computation of basic and diluted net loss:
 
For the Three Months Ended March 31,
 
2015
 
2014
Net loss
$
(9,158
)
 
$
(4,295
)
Denominator (basic and diluted):
 
 
 
Weighted average common shares outstanding
94,033,035

 
91,903,036

Net loss per share:
 
 
 
Basic and diluted
$
(0.10
)
 
$
(0.05
)
Stock Options, Warrants to Purchase Common and Preferred Stock and Convertible Redeemable Preferred Stock Excluded from Computation of Diluted Net Income (Loss) Per Share
The following weighted-average number of outstanding employee stock options, restricted stock units and restricted stock awards, warrants to purchase common stock, and shares purchased under our ESPP were excluded from the computation of diluted net loss per share:  
 
For the Three Months Ended March 31,
 
2015
 
2014
Stock options outstanding
2,898,461

 
5,131,673

Restricted stock units and restricted stock awards
145,676

 
217,010

Common equivalent shares from stock warrants
2,219,671

 
2,378,641

Shares purchased under ESPP
—

 
25,105

 
5,263,808

 
7,752,429