Quarterly report pursuant to Section 13 or 15(d)

Stock Based Compensation - Schedule of Stock-Based Compensation Expense (Details)

v3.8.0.1
Stock Based Compensation - Schedule of Stock-Based Compensation Expense (Details) - USD ($)
$ in Thousands
3 Months Ended 9 Months Ended
Sep. 30, 2017
Sep. 30, 2016
Sep. 30, 2017
Sep. 30, 2016
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]        
Share-based compensation expense $ 551 $ 480 $ 2,239 $ 1,274
Research and Development Expense [Member]        
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]        
Share-based compensation expense 280 212 785 483
General and Administrative Expense [Member]        
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]        
Share-based compensation expense $ 271 $ 268 $ 1,454 $ 791