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Stock-Based Compensation - Additional Information (Detail) - USD ($)
$ / shares in Units, $ in Thousands
3 Months Ended 9 Months Ended
Sep. 30, 2020
Sep. 30, 2020
Sep. 30, 2019
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]      
Aggregate intrinsic value of options exercised   $ 595 $ 3,446
Options Granted, Weighted-average grant-date fair value   $ 12.98 $ 11.77
Total fair value of restricted common stock vested   $ 28 $ 44
Unrecognized stock-based compensation expenses $ 41,143 $ 41,143  
Unrecognized stock-based compensation expense, period for recognition   3 years 29 days  
Additional research and development expenses $ 274 $ 274