Quarterly report pursuant to Section 13 or 15(d)

Stockholders' Equity - Schedule of Stock-based Compensation Related to All Employee And Non-employee Stock Awards (Detail)

v3.10.0.1
Stockholders' Equity - Schedule of Stock-based Compensation Related to All Employee And Non-employee Stock Awards (Detail) - USD ($)
$ in Thousands
3 Months Ended 9 Months Ended
Sep. 30, 2018
Sep. 30, 2017
Sep. 30, 2018
Sep. 30, 2017
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]        
Total stock-based compensation expense $ 9,252 $ 6,000 $ 24,264 $ 17,003
Research and development        
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]        
Total stock-based compensation expense 4,682 2,136 10,997 6,260
General and administrative        
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]        
Total stock-based compensation expense $ 4,570 $ 3,864 $ 13,267 $ 10,743