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Stock-Based Compensation - Summary of Service-based Restricted Stock Activity (Detail) - Restricted Stock [Member] - $ / shares
12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Unvested Beginning balance, Shares 477,187 838,967
Shares awarded, Shares 201,233 190,159
Shares vested, Shares (239,615) (538,137)
Shares cancelled, Shares (3,967) (13,802)
Unvested Ending balance, Shares 434,838 477,187
Unvested Beginning balance, Weighted Average Fair Value $ 6.11 $ 6.21
Shares awarded, Weighted Average Fair Value 7.91 5.25
Shares vested, Weighted Average Fair Value 6.18 5.96
Shares cancelled, Weighted Average Fair Value 6.19 6.27
Unvested Ending balance, Weighted Average Fair Value $ 6.91 $ 6.11