Quarterly report pursuant to Section 13 or 15(d)

Share-Based Compensation - Additional Information (Details)

v3.20.2
Share-Based Compensation - Additional Information (Details) - USD ($)
$ / shares in Units, $ in Thousands
3 Months Ended 6 Months Ended
Feb. 14, 2020
Dec. 05, 2018
Oct. 14, 2016
Oct. 14, 2015
Jun. 30, 2020
Jun. 30, 2019
Jun. 30, 2020
Jun. 30, 2019
Jun. 10, 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         17,852,149   17,852,149     14,868,973        
Share options granted             64,840              
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               $ 167            
Unamortized stock compensation expense           $ 93   $ 93            
Stock-based compensation expense, expected weighted average period for recognition               3 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             $ 663 $ 655            
Unvested employee options outstanding         550,521 925,549 550,521 925,549            
Unamortized compensation expense share options         $ 2,336 $ 4,107 $ 2,336 $ 4,107            
Vesting period             2 years 1 month 2 days 3 years 25 days            
Restricted Share Units (RSUs)                            
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                            
Grant date fair value         $ 7.01   $ 7.01     $ 7.01        
Expense recognized             $ 62 $ 201            
Unamortized stock compensation expense           210   $ 210            
Stock-based compensation expense, expected weighted average period for recognition               11 months 15 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 31,367            
Performance RSUs                            
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                            
Grant date fair value         $ 2.30   $ 2.30     $ 8.21        
Expense recognized             $ 1,058 $ 90            
Unamortized stock compensation expense         $ 1,247 $ 320 $ 1,247 $ 320            
Stock-based compensation expense, expected weighted average period for recognition             5 months 12 days 1 year 3 months 25 days            
Number of shares, granted/awarded         0 0 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             11 months 26 days 2 years 9 months 29 days            
Unamortized compensation expense         $ 3,583 $ 4,730 $ 3,583 $ 4,730            
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             64,840 512,178