XML 138 R106.htm IDEA: XBRL DOCUMENT v3.22.1
Share-based compensation - Summary of Stock Option Activity (Detail) - Share options - 2010 share incentive plan [Member] - USD ($)
$ / shares in Units, $ in Thousands
12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2021
Number of share options        
Outstanding at beginning of period 10,000 16,500    
Vested and expected to vest   10,000 16,500  
Exercisable   10,000 16,500  
Expired (10,000) (6,500)    
Outstanding at end of period   10,000 16,500  
Weighted average exercise price (USD)        
Outstanding at beginning of period $ 3.97 $ 3.97    
Vested and expected to vest   3.97 $ 3.97  
Exercisable   3.97 3.97  
Expired   3.97    
Outstanding at end of period   3.97 3.97  
Weighted average grant-date fair value (USD)        
Vested and expected to vest   1.01 1.56  
Exercisable   $ 1.01 $ 1.56  
Share option activity - additional disclosures        
Weighted-average remaining contractual life, vested and expected to vest   1 year 1 month 28 days 1 year 4 months 13 days  
Weighted-average remaining contractual life, exercisable   1 year 1 month 28 days 1 year 4 months 13 days  
Weighted-average remaining contractual life, outstanding   1 year 1 month 28 days 1 year 4 months 13 days  
Aggregate intrinsic value, vested and expected to vest $ 0 $ 0 $ 0 $ 0
Aggregate intrinsic value, exercisable   0 0  
Aggregate intrinsic value, outstanding $ 0 $ 0 $ 0