XML 90 R74.htm IDEA: XBRL DOCUMENT v3.8.0.1
Share-based compensation - Schedule of Stock Options Activity (Detail) - $ / shares
 12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]      
Number of options, Beginning Balance 352,000 462,000  
Number of options, Additions as a result of the reverse acquisition     407,000
Number of options, Granted   30,000 85,000
Number of options, Forfeited   (40,000) (30,000)
Number of options, Expired (130,000) (100,000)  
Number of options, Ending Balance 222,000 352,000 462,000
Options vested and expected to vest as of December 31, 2017 222,000    
Number of options, Options Exercisable 174,500    
Weighted average exercise price per share, Beginning Balance $ 10.25 $ 9.52  
Weighted average exercise price per share, Additions as a result of the reverse acquisition     $ 9.21
Weighted average exercise price per share, Granted   5.04 10.39
Weighted average exercise price per share, Forfeited   8.45 7.85
Weighted average exercise price per share, Expired 6.25 6.02  
Weighted average exercise price per share, Ending Balance 12.59 $ 10.25 $ 9.52
Options vested and expected to vest as of December 31, 2017 12.59    
Weighted average exercise price per share, Options Exercisable $ 10.05    
Outstanding as of December 31, 2015 5 years 4 months 24 days 4 years 4 months 24 days 5 years 3 months 18 days
Options vested and expected to vest as of December 31, 2017 5 years 4 months 24 days    
Weighted average remaining contractual term, Options exercisable 4 years 8 months 12 days