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Stock-based Compensation - Summary of Restricted Stock Activity (Detail) - Restricted Stock [Member]
9 Months Ended
Sep. 30, 2020
$ / shares
shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Unvested restricted common shares, Number of Shares, Beginning Balance | shares 699,534
Unvested restricted common shares, Number of Shares, Granted | shares 306,220
Unvested restricted common shares, Number of Shares, Vested | shares (74,583)
Unvested restricted common shares, Number of Shares, Cancelled or forfeited | shares (33,661)
Unvested restricted common shares, Number of Shares, Ending Balance | shares 897,510
Unvested restricted common shares, Weighted-Average Grant Date Fair Value, Beginning Balance | $ / shares $ 56.53
Unvested restricted common shares, Weighted-Average Grant Date Fair Value, Granted | $ / shares 49.01
Unvested restricted common shares, Weighted-Average Grant Date Fair Value, Vested | $ / shares 50.60
Unvested restricted common shares, Weighted-Average Grant Date Fair Value, Cancelled or forfeited | $ / shares 46.23
Unvested restricted common shares, Weighted-Average Grant Date Fair Value, Ending Balance | $ / shares $ 54.84