XML 85 R72.htm IDEA: XBRL DOCUMENT v3.10.0.1
Stock award plan - Stock Option Activity (Details) - Stock option - USD ($)
$ / shares in Units, $ in Thousands
12 Months Ended
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Number of options      
Outstanding at the beginning of the period (in shares) 6,448,642 5,854,316 4,826,477
Granted (in shares) 3,181,623 1,913,873 1,500,645
Exercised (in shares) (633,973) (202,085) (89,216)
Forfeited (in shares) (461,934) (1,117,462) (383,590)
Outstanding at the end of the period (in shares) 8,534,358 6,448,642 5,854,316
Vested or expected to vest at the end of the period (in shares) 3,881,360    
Exercisable at the end of the period (in shares) 4,410,211    
Weighted- average exercise price      
Outstanding at the beginning of the period (in dollars per share) $ 29.00 $ 34.71 $ 37.20
Granted (in dollars per share) 26.64 12.34 27.90
Exercised (in dollars per share) 18.61 10.80 10.85
Forfeited (in dollars per share) 35.36 33.65 47.42
Outstanding at the end of the period (in dollars per share) 28.58 $ 29.00 $ 34.71
Vested or expected to vest at the end of the period (in dollars per share) 24.81    
Exercisable at the end of the period (in dollars per share) $ 32.01    
Weighted- average remaining contractual term      
Outstanding at the end of the period 7 years 4 months 13 days    
Vested or expected to vest at the end of the period 8 years 9 months 14 days    
Exercisable at the end of the period 6 years 8 days    
Aggregate intrinsic value      
Outstanding at the end of the period (in dollars) $ 88,454    
Vested or expected to vest at the end of the period (in dollars) 44,893    
Exercisable at the end of the period (in dollars) $ 40,854