Quarterly report pursuant to Section 13 or 15(d)

Share-Based Compensation - Additional Information (Details)

v3.10.0.1
Share-Based Compensation - Additional Information (Details) - USD ($)
$ / shares in Units, $ in Thousands
9 Months Ended
Oct. 14, 2016
Oct. 14, 2015
Sep. 30, 2018
Sep. 30, 2017
Mar. 14, 2018
Dec. 31, 2017
Nov. 18, 2015
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]              
Stock options awarded     449,986        
Restricted Ordinary Shares              
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]              
Shares issued in the period   413,110          
Percentage of remaining restricted ordinary shares vest on monthly basis 0.0278%            
Grant date fair value     $ 3.14     $ 3.14 $ 3.14
Expense recognized     $ 249 $ 249      
Unamortized stock compensation expense     $ 344 $ 677      
Stock-based compensation expense, expected weighted average period for recognition     1 year 14 days 2 years 14 days      
Restricted Ordinary Shares | Tranche One              
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]              
Percentage of awards vested 25.00%            
Employee Stock Options              
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]              
Expense recognized     $ 459 $ 31      
Unvested employee options outstanding     619,252 224,673      
Unamortized compensation expense stock options     $ 3,320 $ 397      
Vesting period     3 years 6 months 10 days 3 years 8 months 15 days      
Restricted Stock Units (RSUs)              
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]              
Grant date fair value     $ 13.00        
Expense recognized     $ 170        
Unamortized stock compensation expense     $ 311        
Stock-based compensation expense, expected weighted average period for recognition     7 months 24 days        
Number of Shares, Granted     36,924 0      
Restricted Stock Units (RSUs) | Director              
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]              
Vesting period     1 year        
Restricted Ordinary Shares, Options and Restricted Stock Units              
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]              
Vesting period     3 years 1 month 2 days 2 years 7 months 28 days      
Unamortized compensation expense     $ 3,976 $ 1,076      
2018 Plan              
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]              
Number of shares authorized         1,018,459    
2018 Plan | Employees and Directors              
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]              
Stock options awarded     449,986        
2015 Plan | Employees and Directors              
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]              
Stock options awarded       188,296