XML 117 R98.htm IDEA: XBRL DOCUMENT v3.8.0.1
Share-Based Compensation - 2011 Share Award Scheme (Detail) - Restricted Stock [Member] - 2011 Share Award Scheme - $ / shares
12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Unvested at beginning of year 7,007,672  
Granted 484,000  
Vested (3,128,262)  
Forfeited (916,910)  
Unvested at end of year 3,446,500 7,007,672
Unvested at beginning of year $ 1.30  
Granted (in dollars per share) 0.91 $ 1.61
Vested (in dollars per share) 1.23  
Forfeited (in dollars per share) 1.23  
Unvested at end of year $ 1.32 $ 1.30