Annual report pursuant to Section 13 and 15(d)

Stockholders' Equity - Share-Based Compensation (Details)

v3.8.0.1
Stockholders' Equity - Share-Based Compensation (Details) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Share-based compensation expense $ 24,915 $ 18,893 $ 12,458
Research and development expenses      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Share-based compensation expense 14,235 8,836 4,080
General and administrative expenses      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Share-based compensation expense $ 10,680 $ 10,057 $ 8,378