Leases - Cash flows (Details) $ in Thousands  | 
9 Months Ended | 
|---|---|
| 
 Sep. 30, 2019  
USD ($) 
 | |
| Leases | |
| Operating cash flows from operating leases | $ 52 | 
| Weighted-average remaining lease term - operating leases | 4 years 6 months | 
| Weighted-average discount rate - operating leases | 8.96% | 
| X | ||||||||||
- References No definition available. 
  | 
| X | ||||||||||
- Definition Amount of cash outflow from operating lease, excluding payments to bring another asset to condition and location necessary for its intended use. Reference 1: http://www.xbrl.org/2003/role/disclosureRef 
  | 
| X | ||||||||||
- Definition Weighted average discount rate for operating lease calculated at point in time. Reference 1: http://www.xbrl.org/2003/role/disclosureRef 
  | 
| X | ||||||||||
- Definition Weighted average remaining lease term for operating lease, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Reference 1: http://www.xbrl.org/2003/role/exampleRef 
  |