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Stock-based Compensation - Summary of Restricted Stock Activity (Detail) - Restricted Stock [Member]
3 Months Ended
Mar. 31, 2021
$ / shares
shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Unvested restricted common shares, Number of Shares, Beginning Balance | shares 894,092
Unvested restricted common shares, Number of Shares, Granted | shares 278,645
Unvested restricted common shares, Number of Shares, Vested | shares (109,355)
Unvested restricted common shares, Number of Shares, Cancelled or forfeited | shares (11,003)
Unvested restricted common shares, Number of Shares, Ending Balance | shares 1,052,379
Unvested restricted common shares, Weighted-Average Grant Date Fair Value, Beginning Balance | $ / shares $ 70.55
Unvested restricted common shares, Weighted-Average Grant Date Fair Value, Granted | $ / shares 136.16
Unvested restricted common shares, Weighted-Average Grant Date Fair Value, Vested | $ / shares 40.64
Unvested restricted common shares, Weighted-Average Grant Date Fair Value, Cancelled or forfeited | $ / shares 57.94
Unvested restricted common shares, Weighted-Average Grant Date Fair Value, Ending Balance | $ / shares $ 91.16