Commitments and Contingencies - Leases, Components of lease expense (Details) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2020 USD ($)	Jun. 30, 2020 USD ($)
Commitments and Contingencies
Operating lease cost	$ 220	$ 443
Variable lease cost	164	303
Total lease cost	$ 384	$ 746
Weighted-average remaining operating lease term (years)	2 years 2 months 12 days	2 years 2 months 12 days
Weighted-average discount rate	8.59%	8.59%