Net Loss Per Share - Schedule of Anti-dilutive Shares Excluded from the Calculation of Diluted Net Loss Per Share (Details 2) - shares
shares in Thousands |
12 Months Ended |
Dec. 31, 2015 |
Dec. 31, 2014 |
Dec. 31, 2013 |
| Anti-dilutive shares excluded from the calculation of diluted net loss per share attributable to common stockholders |
|
|
|
| Total shares excluded from net loss per share attributable to common stockholders |
29,656
|
30,344
|
27,206
|
| Options to purchase common stock |
|
|
|
| Anti-dilutive shares excluded from the calculation of diluted net loss per share attributable to common stockholders |
|
|
|
| Total shares excluded from net loss per share attributable to common stockholders |
24,278
|
25,590
|
18,363
|
| Common stock warrants |
|
|
|
| Anti-dilutive shares excluded from the calculation of diluted net loss per share attributable to common stockholders |
|
|
|
| Total shares excluded from net loss per share attributable to common stockholders |
1,631
|
3,926
|
5,931
|
| Conversion of convertible preferred stock |
|
|
|
| Anti-dilutive shares excluded from the calculation of diluted net loss per share attributable to common stockholders |
|
|
|
| Total shares excluded from net loss per share attributable to common stockholders |
0
|
0
|
2,857
|
| Unvested restricted stock awards |
|
|
|
| Anti-dilutive shares excluded from the calculation of diluted net loss per share attributable to common stockholders |
|
|
|
| Total shares excluded from net loss per share attributable to common stockholders |
3,747
|
828
|
55
|