Net Loss Per Share (Details) - shares shares in Thousands |
3 Months Ended | 9 Months Ended | ||
|---|---|---|---|---|
Sep. 30, 2017 |
Sep. 30, 2016 |
Sep. 30, 2017 |
Sep. 30, 2016 |
|
| Antidilutive securities excluded from the computation of diluted net loss per share | ||||
| Antidilutive securities excluded from computation of earnings per share (in shares) | 20,790 | 21,160 | 20,790 | 21,160 |
| 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) | 20,721 | 20,897 | 20,721 | 20,897 |
| 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 | ||
| Purchase plan | ||||
| Antidilutive securities excluded from the computation of diluted net loss per share | ||||
| Antidilutive securities excluded from computation of earnings per share (in shares) | 69 | 63 | 69 | 63 |