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Cash, Cash Equivalents, Restricted Cash and Marketable Securities - Additional Information (Detail) - USD ($)
3 Months Ended 6 Months Ended
Jun. 30, 2021
Jun. 30, 2020
Jun. 30, 2021
Jun. 30, 2020
Investments Debt And Equity Securities [Abstract]        
Realized gains on investments $ 0 $ 0 $ 0 $ 0
Realized loss on investments     $ 0