Net loss per share (Details) - shares shares in Thousands |
3 Months Ended | 9 Months Ended | ||
|---|---|---|---|---|
Sep. 30, 2015 |
Sep. 30, 2014 |
Sep. 30, 2015 |
Sep. 30, 2014 |
|
| Antidilutive securities excluded from the computation of diluted net loss per share | ||||
| Antidilutive securities excluded from computation of earnings per share (in shares) | 19,989 | 17,639 | 19,989 | 17,639 |
| Employee Stock Option | ||||
| Antidilutive securities excluded from the computation of diluted net loss per share | ||||
| Antidilutive securities excluded from computation of earnings per share (in shares) | 19,711 | 17,336 | 19,711 | 17,336 |
| Warrant to purchase common stock | ||||
| Antidilutive securities excluded from the computation of diluted net loss per share | ||||
| Antidilutive securities excluded from computation of earnings per share (in shares) | 200 | 200 | 200 | 200 |
| Employee Stock | ||||
| Antidilutive securities excluded from the computation of diluted net loss per share | ||||
| Antidilutive securities excluded from computation of earnings per share (in shares) | 78 | 103 | 78 | 103 |