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Stock-Based Compensation - Schedule of Weighted Average Grant Date Fair Value of Restricted Stock Units Issued (Detail) - $ / shares
12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Restricted Stock Units [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Weighted-average grant date fair value, Granted $ 6.54 $ 12.48 $ 16.76