Net Loss Per Share (Details 1) - shares shares in Thousands |
3 Months Ended | 6 Months Ended | ||
|---|---|---|---|---|
Jun. 30, 2018 |
Jun. 30, 2017 |
Jun. 30, 2018 |
Jun. 30, 2017 |
|
| Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] | ||||
| Weighted-average anti-dilutive common shares | 5,140 | 3,554 | 5,057 | 2,841 |
| Employee Stock Option [Member] | ||||
| Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] | ||||
| Weighted-average anti-dilutive common shares | 3,658 | 2,437 | 3,327 | 2,324 |
| Warrants [Member] | ||||
| Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] | ||||
| Weighted-average anti-dilutive common shares | 1,482 | 1,117 | 1,730 | 517 |