Annual report pursuant to Section 13 and 15(d)

Common Stock - Summary of Share-Based Compensation Expense (Detail)

v3.20.1
Common Stock - Summary of Share-Based Compensation Expense (Detail) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]      
Total stock-based compensation $ 1,201 $ 854 $ 348
Research and development [Member]      
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]      
Total stock-based compensation 364 272  
General and administrative [Member]      
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]      
Total stock-based compensation $ 837 $ 582