Summary of Significant Accounting Policies - Schedule of Cash and Cash Equivalents and Restricted Cash (Detail) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020	Sep. 30, 2020	Dec. 31, 2019
Accounting Policies [Abstract]
Cash and cash equivalents	$ 10,669	$ 17,885	$ 14,293
Restricted cash	5,882	4,982	3,982
Total cash and restricted cash	$ 16,551	$ 22,867	$ 18,275	$ 37,063