Summary of significant accounting policies - Additional information (Details) shares in Thousands |
12 Months Ended | |
|---|---|---|
|
Dec. 31, 2019
USD ($)
Segment
shares
|
Dec. 31, 2018
USD ($)
shares
|
|
| Segment information | ||
| Number of operating segments | Segment | 1 | |
| Asset Impairment Charges | ||
| Asset impairment | $ | $ 0 | $ 0 |
| Common stock equivalents, presented on an as converted basis, were excluded from the calculation of net loss per share for the periods presented, due to their anti-dilutive effect | ||
| Common stock equivalents (in shares) | 5,914 | 4,561 |
| Warrant | ||
| Common stock equivalents, presented on an as converted basis, were excluded from the calculation of net loss per share for the periods presented, due to their anti-dilutive effect | ||
| Common stock equivalents (in shares) | 4,591 | 3,668 |