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Property and Equipment, Net - Additional Information (Detail) - USD ($)
3 Months Ended 12 Months Ended
Sep. 30, 2019
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Property Plant And Equipment [Abstract]        
Depreciation and amortization   $ 4,273,000 $ 8,938,000 $ 3,621,000
Accelerated depreciation charges $ 3,000,000.0   $ 3,000,000.0