Commitments and Contingencies - Leases, Components of lease expense (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2019 USD ($)
Commitments and Contingencies
Operating lease cost	$ 900
Variable lease cost	390
Total lease cost	$ 1,290
Weighted-average remaining operating lease term (years)	2 years 7 months 6 days
Weighted-average discount rate	8.52%