Quarterly report pursuant to Section 13 or 15(d)

Stockholders' Equity (Details 3)

v3.8.0.1
Stockholders' Equity (Details 3) - USD ($)
$ in Thousands
3 Months Ended
Mar. 31, 2018
Mar. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Employee Benefits and Share-based Compensation $ 1,137 $ 979
Research and development    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Employee Benefits and Share-based Compensation 680 406
General and administrative    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Employee Benefits and Share-based Compensation $ 457 $ 573