Quarterly report pursuant to Section 13 or 15(d)

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

v3.10.0.1
Stock-Based Compensation - Summary of Stock-based Compensation Expense (Detail) - Omnibus Plan [Member] - USD ($)
$ in Thousands
3 Months Ended 6 Months Ended
Jun. 30, 2018
Jun. 30, 2017
Jun. 30, 2018
Jun. 30, 2017
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]        
Stock-based compensation expense $ 2,292 $ 443 $ 2,224 $ 443
Selling, General and Administrative [Member]        
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]        
Stock-based compensation expense 967 422 1,336 422
Research and Development [Member]        
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]        
Stock-based compensation expense 1,325 21 888 21
Employee Stock Options [Member]        
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]        
Stock-based compensation expense 278   576  
Employee Restricted Stock Units [Member]        
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]        
Stock-based compensation expense 384 435 819 435
Nonemployee Stock Options [Member]        
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]        
Stock-based compensation expense 1,138   426  
Nonemployee Restricted Stock Units [Member]        
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]        
Stock-based compensation expense $ 492 $ 8 $ 403 $ 8