Supplemental Disclosures to the Unaudited Condensed Consolidated Balance Sheets and Unaudited Condensed Consolidated Statements of Cash Flows - Summary of Cash and Cash Equivalents Reconciliation (Detail) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019	Sep. 30, 2019	Dec. 31, 2018
Cash And Cash Equivalents [Abstract]
Cash and cash equivalents	$ 13,521	$ 0
Restricted cash	0	325
Total cash, cash equivalents and restricted cash	$ 13,521	$ 325	$ 7,733	$ 50,029