Summary of Significant Accounting Policies - Summary of Cash, Cash Equivalents and Restricted Cash (Detail) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents [Abstract]
Cash and cash equivalents	$ 433,909	$ 39,946
Restricted cash, included in prepaid expenses and other current assets	$ 1,316	$ 979
Restricted cash, current, asset, statement of financial position [extensible list]	us-gaap:OtherAssetsCurrent	us-gaap:OtherAssetsCurrent
Total cash, cash equivalents and restricted cash	$ 435,225	$ 40,925	$ 35,007	$ 33,997