Commitments and Contingencies - Operating Lease Right-of-Use Assets and Liabilities (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Assets
Operating lease right-of-use assets	$ 2,612	$ 2,825
Liabilities
Operating lease short-term liabilities (recorded within Accrued liabilities)	351
Operating lease long-term liabilities (recorded within Lease-related obligations)	2,654	2,814
Total present value of lease payments	$ 3,005	$ 2,926
Operating Lease, Liability, Current, Statement of Financial Position [Extensible List]	us-gaap:AccruedLiabilitiesCurrent	us-gaap:AccruedLiabilitiesCurrent