Annual report pursuant to Section 13 and 15(d)

Stock Plans - Stock-based compensation expense and impact (Details)

v3.20.1
Stock Plans - Stock-based compensation expense and impact (Details) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2019
Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost    
Total stock-based compensation expense $ 572 $ 1,557
Research and development    
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost    
Total stock-based compensation expense 91 575
General and administrative    
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost    
Total stock-based compensation expense $ 481 $ 982