Annual report pursuant to Section 13 and 15(d)

Stockholders' Equity (Details 3)

v3.19.1
Stockholders' Equity (Details 3) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2018
Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Employee Benefits and Share-based Compensation $ 1,994 $ 3,117
Research and development    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Employee Benefits and Share-based Compensation 95 1,180
General and administrative    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Employee Benefits and Share-based Compensation $ 1,899 $ 1,937