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Concentration of Credit Risk - Additional Information (Detail) - Credit Concentration Risk
3 Months Ended
Mar. 31, 2021
Mar. 31, 2020
Accounts Receivable    
Concentration Risk [Line Items]    
Concentration risk, percentage 100.00% 100.00%
Revenue    
Concentration Risk [Line Items]    
Concentration risk, percentage 100.00% 100.00%