Commitments and Contingencies - Schedule of ROU Assets and Liabilities Related to 2014 Lease and Temporary Lease (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Commitments And Contingencies Disclosure [Abstract]
ROU assets (included in other assets)	$ 45
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]	us-gaap:OtherAssets
Lease liabilities, current portion (included in accounts payable and accrued liabilities)	$ 100
Operating lease, liability, current, statement of financial position [Extensible List]	Accounts payable and accrued liabilities
Lease liabilities, net of current portion	$ 877	$ 938
Total lease liabilities	$ 977