Annual report pursuant to Section 13 and 15(d)

Stock-Based Compensation - Stock Options - Additional Information (Detail)

v3.19.1
Stock-Based Compensation - Stock Options - Additional Information (Detail) - USD ($)
$ in Thousands
1 Months Ended 12 Months Ended
Dec. 31, 2017
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Stock-based compensation expense   $ 4,385 $ 12,091 $ 948
Aggregate intrinsic value of options outstanding and exercisable   $ 5,900    
Weighted average remaining contractual term   7 years 7 months 6 days    
2017 Omnibus Plan [Member]        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Stock option expiration period   10 years    
Stock option, vesting period   6 years    
Stock-based compensation expense   $ 4,400 $ 11,700 $ 0
2017 Omnibus Plan [Member] | Employee Termination [Member]        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Stock-based compensation expense $ 700      
2017 Omnibus Plan [Member] | IPO [Member]        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Stock-based compensation expense   $ 5,600    
Completion date of initial public offering   July 25, 2017    
2017 Omnibus Plan [Member] | Minimum [Member]        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Options priced at fair marrket value, percent   100.00%