Quarterly report pursuant to Section 13 or 15(d)

Stock-Based Compensation - Summary of Stock-based Compensation Expense (Detail)

v3.8.0.1
Stock-Based Compensation - Summary of Stock-based Compensation Expense (Detail) - Omnibus Plan [Member] - USD ($)
$ in Thousands
3 Months Ended 9 Months Ended
Sep. 30, 2017
Sep. 30, 2017
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]    
Stock-based compensation expense $ 9,191 $ 9,634
Selling, General and Administrative [Member]    
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]    
Stock-based compensation expense 4,539 4,961
Research and Development [Member]    
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]    
Stock-based compensation expense 4,652 4,673
Employee Stock Options [Member]    
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]    
Stock-based compensation expense 3,891 3,891
Employee Restricted Stock Units [Member]    
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]    
Stock-based compensation expense 706 1,141
Nonemployee Stock Options [Member]    
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]    
Stock-based compensation expense 4,209 4,209
Nonemployee Restricted Stock Units [Member]    
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]    
Stock-based compensation expense $ 385 $ 393