Quarterly report pursuant to Section 13 or 15(d)

Stock-based Compensation - Expense Related to Stock Options (Detail)

v3.20.2
Stock-based Compensation - Expense Related to Stock Options (Detail) - USD ($)
$ in Thousands
3 Months Ended 9 Months Ended
Sep. 30, 2020
Sep. 30, 2019
Sep. 30, 2020
Sep. 30, 2019
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]        
Stock-based compensation expense related to stock options $ 399 $ 449 $ 1,220 $ 1,387
Research and development, net        
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]        
Stock-based compensation expense related to stock options 130 148 394 471
Selling, general and administrative        
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]        
Stock-based compensation expense related to stock options $ 269 $ 301 $ 826 $ 916