v2.4.0.8
Stock options (Details) (USD $)
In Thousands, except Per Share data, unless otherwise specified
9 Months Ended 12 Months Ended
Oct. 31, 2014
Jan. 31, 2014
Number of options    
Opening balance 6,369  
Granted 1,946  
Exercised (1,793)  
Forfeited (169)  
Ending balance 6,353 6,369
Range of exercise prices (usd per share)    
Beginning balance, minimum $ 1.10  
Beginning balance, maximum $ 4.50  
Granted, minimum $ 14.00  
Granted, maximum $ 18.93  
Exercised, minimum $ 0.50  
Exercised, maximum $ 2.50  
Forfeited, minimum $ 1.25  
Forfeited, maximum $ 14.00  
Ending balance, minimum $ 1.10 $ 1.10
Ending balance, maximum $ 18.93 $ 4.50
Weighted- average exercise price (usd per share)    
Opening balance $ 1.77  
Granted $ 14.29  
Exercised $ 1.3370  
Forfeited $ 9.97  
Ending balance $ 4.79 $ 1.77
Weighted- average contractual term (in years) 7 years 0 months 10 days 6 years 4 months 2 days
Aggregate intrinsic value $ 99,157 $ 14,621