Commitments and Contingencies - Operating Lease Right-of-Use Assets and Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Assets
Operating lease right-of-use assets	$ 2,717	$ 2,825
Liabilities
Operating lease short-term liabilities (recorded within Accrued liabilities)	105
Operating lease long-term liabilities (recorded within Lease-related obligations)	2,752	2,814
Total present value of lease payments	$ 2,857	$ 2,926
Operating Lease, Liability, Current, Statement of Financial Position [Extensible List]	us-gaap:AccruedLiabilitiesCurrent