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Related Party Transactions - Additional Information (Detail) - Director [Member] - USD ($)
$ in Millions
3 Months Ended 9 Months Ended
Sep. 30, 2021
Sep. 30, 2020
Sep. 30, 2021
Sep. 30, 2020
Related Party Transaction [Line Items]        
Compensation expense $ 0.1   $ 0.3 $ 0.2
Maximum [Member]        
Related Party Transaction [Line Items]        
Compensation expense   $ 0.1