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Stockholders' Equity - Additional Information - Deferred Stock Units (Detail) - Deferred Stock Units [Member] - USD ($)
3 Months Ended
Mar. 31, 2021
Dec. 31, 2020
Sep. 01, 2019
Schedule Of Stockholders Equity [Line Items]      
Number of stock unit received     1
Deferred stock units 2,845    
Compensation expense related to grants $ 79,768    
DSUs outstanding 89,409 73,231  
Director [Member]      
Schedule Of Stockholders Equity [Line Items]      
Compensation expense related to grants $ 8,661    
Executive Employees [Member]      
Schedule Of Stockholders Equity [Line Items]      
Deferred stock units 13,333