Fair Value - Fair value of warrant liability reconciliation (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended
	Dec. 31, 2020	Mar. 31, 2021
Warrant Liability
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Initial fair value at inception, Beginning balance	$ 11,550	$ 8,790
Change in fair value	(2,760)	(105)
Fair value of warrant liability, Ending balance	8,790	8,685
Maximum cash settlement of warrant		2,018
Contingent Value Rights Liability
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Initial fair value at inception, Beginning balance	681	656
Change in fair value	(25)	(155)
Fair value of warrant liability, Ending balance	$ 656	$ 501