Quarterly report pursuant to Section 13 or 15(d)

Stock Plans and Stock-Based Compensation - Summary of Stock-Based Compensation Expense, Net of Estimated Forfeitures (Detail)

v3.7.0.1
Stock Plans and Stock-Based Compensation - Summary of Stock-Based Compensation Expense, Net of Estimated Forfeitures (Detail) - USD ($)
$ in Thousands
3 Months Ended 6 Months Ended
Jun. 30, 2017
Jun. 30, 2016
Jun. 30, 2017
Jun. 30, 2016
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]        
Stock-based compensation expense $ 1,840 $ 570 $ 3,118 $ 1,130
Research and Development [Member]        
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]        
Stock-based compensation expense 268 223 628 445
General and Administrative [Member]        
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]        
Stock-based compensation expense $ 1,572 $ 347 $ 2,490 $ 685