Quarterly report pursuant to Section 13 or 15(d)

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

v3.20.1
Stock-based Compensation - Expense Related to Stock Options (Detail) - USD ($)
$ in Thousands
3 Months Ended
Mar. 31, 2020
Mar. 31, 2019
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]    
Stock-based compensation expense related to stock options $ 410 $ 492
Research and development, net    
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]    
Stock-based compensation expense related to stock options 136 158
Selling, general and administrative    
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]    
Stock-based compensation expense related to stock options $ 274 $ 334