Summary of Significant Accounting Policies - Schedule of Reconciliation of Cash, Cash Equivalents and Restricted Cash (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020	Sep. 30, 2020	Dec. 31, 2019
Accounting Policies [Abstract]
Cash and cash equivalents	$ 21,994	$ 17,807
Restricted cash	1,446	1,446
Total cash, cash equivalents, and restricted cash	$ 23,440	$ 19,253	$ 50,027	$ 38,919