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Stock-Based Compensation - Summary of Compensation Expense by Type of Award (Detail) - USD ($)
$ in Thousands
 3 Months Ended 6 Months Ended
Jun. 30, 2020
Jun. 30, 2019
Jun. 30, 2020
Jun. 30, 2019
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]        
Total stock-based compensation $ 1,936 $ 766 $ 2,646 $ 1,539
Stock Options [Member]        
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]        
Total stock-based compensation 1,737 509 2,243 1,042
ESPP [Member]        
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]        
Total stock-based compensation $ 199 $ 257 $ 403 $ 497