Quarterly report pursuant to Section 13 or 15(d)

Share-Based Compensation - Additional Information (Details)

v3.20.1
Share-Based Compensation - Additional Information (Details) - USD ($)
$ / shares in Units, $ in Thousands
3 Months Ended
Feb. 14, 2020
Dec. 05, 2018
Oct. 14, 2016
Oct. 14, 2015
Mar. 31, 2020
Mar. 31, 2019
Mar. 11, 2020
Dec. 31, 2019
Dec. 31, 2018
Mar. 14, 2018
May 18, 2017
Nov. 18, 2015
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                        
Ordinary shares, shares issued         14,868,973     14,868,973        
Share options granted         2,000              
Restricted Ordinary Shares                        
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                        
Shares issued in the period       413,110 0              
Percentage of remaining restricted ordinary shares vest on monthly basis     0.0278%                  
Grant date fair value                       $ 3.14
Expense recognized           $ 85            
Unamortized stock compensation expense           $ 175            
Stock-based compensation expense, expected weighted average period for recognition           6 months 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         $ 347 $ 307            
Unvested employee options outstanding         605,486 984,913            
Unamortized compensation expense share options         $ 2,621 $ 4,168            
Vesting period         2 years 3 months 10 days 3 years 3 months 18 days            
Restricted Share Units (RSUs)                        
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                        
Grant date fair value         $ 7.01     $ 7.01        
Expense recognized         $ 24 $ 119            
Unamortized stock compensation expense         $ 36 $ 72            
Stock-based compensation expense, expected weighted average period for recognition         2 months 12 days 1 month 24 days            
Restricted Share Units (RSUs) | Director                        
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                        
Vesting period         1 year              
Number of shares, granted/awarded         0 0            
Performance RSUs                        
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                        
Grant date fair value         $ 2.30     $ 8.21        
Expense recognized         $ 226 $ 29            
Unamortized stock compensation expense         $ 2,150 $ 381            
Stock-based compensation expense, expected weighted average period for recognition         8 months 12 days 1 year 6 months 21 days            
Number of shares, granted/awarded         1,079,000 50,000            
Restricted Ordinary Shares, Options and Restricted Share Units and Performance RSUs                        
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                        
Vesting period         1 year 2 months 26 days 2 years 11 months 23 days            
Unamortized compensation expense         $ 4,807 $ 4,796            
2015 Plan                        
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                        
Number of shares authorized                       223,424
Number of ordinary shares available for issuance                     443,029 219,605
2018 Plan                        
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                        
Number of shares authorized                   1,018,459    
Increase in number of ordinary shares available to be granted, percentage 4.00% 4.00%                    
Ordinary shares, shares issued 594,758           2,250,000   574,081      
2018 Plan | Employees and Directors                        
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                        
Share options granted         2,000 442,500