Annual and transition report of foreign private issuers pursuant to Section 13 or 15(d)

Equity (Summary of Stock Options Outstanding) (Details)

v3.8.0.1
Equity (Summary of Stock Options Outstanding) (Details) - USD ($)
$ / shares in Units, $ in Thousands
 12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]    
Options Outstanding, Number Outstanding 3,330,953 2,615,461
Options Outstanding, Weighted-Average Remaining Contractual Life in Years 7 years 8 months 16 days  
Options Outstanding, Weighted-Average Exercise Price $ 31.53 $ 37.21
Options Exercisable, Number Exercisable 1,109,094  
Options Exercisable, Weighted-Average Exercise Price $ 49.68  
Options Outstanding, Aggregate intrinsic value $ 597  
Options Exercisable, Aggregate intrinsic value $ 201  
$2.74 - $9.32 [Member]    
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]    
Range of Exercise Prices (Lower) $ 2.74  
Range of Exercise Prices (Upper) $ 9.32  
Options Outstanding, Number Outstanding 14,539  
Options Outstanding, Weighted-Average Remaining Contractual Life in Years 4 years 29 days  
Options Outstanding, Weighted-Average Exercise Price $ 6.77  
Options Exercisable, Number Exercisable 14,536  
Options Exercisable, Weighted-Average Exercise Price $ 6.77  
$19.66 - $19.66 [Member]    
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]    
Range of Exercise Prices (Lower) 19.66  
Range of Exercise Prices (Upper) $ 19.66  
Options Outstanding, Number Outstanding 1,351,385  
Options Outstanding, Weighted-Average Remaining Contractual Life in Years 8 years 11 months 8 days  
Options Outstanding, Weighted-Average Exercise Price $ 19.66  
Options Exercisable, Number Exercisable 30,339  
Options Exercisable, Weighted-Average Exercise Price $ 19.66  
$19.96 - $24.66 [Member]    
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]    
Range of Exercise Prices (Lower) 19.96  
Range of Exercise Prices (Upper) $ 24.66  
Options Outstanding, Number Outstanding 887,398  
Options Outstanding, Weighted-Average Remaining Contractual Life in Years 8 years 6 months 25 days  
Options Outstanding, Weighted-Average Exercise Price $ 21.94  
Options Exercisable, Number Exercisable 282,367  
Options Exercisable, Weighted-Average Exercise Price $ 22.55  
$27.83 - $120.51 [Member]    
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]    
Range of Exercise Prices (Lower) 27.83  
Range of Exercise Prices (Upper) $ 120.51  
Options Outstanding, Number Outstanding 1,077,631  
Options Outstanding, Weighted-Average Remaining Contractual Life in Years 5 years 6 months 7 days  
Options Outstanding, Weighted-Average Exercise Price $ 54.89  
Options Exercisable, Number Exercisable 781,852  
Options Exercisable, Weighted-Average Exercise Price $ 61.45