v3.23.1
Stock-based compensation expense - Stock Option Activity (Details) - USD ($)
$ / shares in Units, shares in Thousands, $ in Thousands
12 Months Ended
Sep. 30, 2022
Sep. 30, 2021
Sep. 30, 2020
Shares      
Number of options, Outstanding beginning balance (in shares) 2,875    
Granted (in shares) 223    
Forfeited (in shares) (161)    
Exercised (in shares) (484)    
Number of options, Outstanding ending balance (in shares) 2,453 2,875  
Number of options, Nonvested at September 30, 2022 (in shares) 581    
Number of options, Exercisable (in shares) 1,872    
Weighted average exercise price per share      
Weighted average exercise price per share, Outstanding beginning balance (in dollars per share) $ 22.83    
Granted (in dollars per share) 24.03 $ 42.80 $ 20.76
Forfeited (in dollars per share) 35.79    
Exercised (in dollars per share) 12.42    
Weighted average exercise price per share, Outstanding ending balance (in dollars per share) 24.67 $ 22.83  
Weighted average exercise price per share, Nonvested at September 30, 2022 (in dollars per share) 32.61    
Weighted average exercise price per share, Exercisable (in dollars per share) $ 22.20    
Weighted average remaining contractual term (years)      
Outstanding 6 years 3 months 29 days 7 years 1 month 9 days  
Granted 9 years 2 months 15 days    
Weighted average remaining contractual term (years), Nonvested at September 30, 2022 7 years 2 months 12 days    
Weighted average remaining contractual term (years), Exercisable 6 years 18 days    
Aggregate intrinsic value      
Aggregate intrinsic value, outstanding beginning balance $ 242,291    
Exercised 31,918    
Aggregate intrinsic value, outstanding ending balance 33,447 $ 242,291  
Aggregate intrinsic value, Nonvested at September 30, 2022 5,435    
Aggregate intrinsic value, Exercisable $ 28,012    
Performance Stock Options      
Shares      
Number of options, Outstanding beginning balance (in shares) 256    
Granted (in shares) 75    
Forfeited (in shares) (19)    
Vested (in shares) (19)    
Number of options, Outstanding ending balance (in shares) 293 256  
Number of options, Nonvested at September 30, 2022 (in shares) 312    
Number of options, Exercisable (in shares) 19    
Weighted average exercise price per share      
Weighted average exercise price per share, Outstanding beginning balance (in dollars per share) $ 70.62    
Granted (in dollars per share) 31.29 $ 45.18 $ 43.06
Forfeited (in dollars per share) 67.85    
Vested (in dollars per share) 31.29    
Weighted average exercise price per share, Outstanding ending balance (in dollars per share) 61.35 $ 70.62  
Weighted average exercise price per share, Nonvested at September 30, 2022 (in dollars per share) 63.27    
Weighted average exercise price per share, Exercisable (in dollars per share) $ 31.29    
Weighted average remaining contractual term (years)      
Outstanding 8 years 3 months 29 days 8 years 11 months 8 days  
Granted 9 years 6 months 25 days    
Weighted average remaining contractual term (years), Nonvested at September 30, 2022 8 years 3 months    
Weighted average remaining contractual term (years), Exercisable 9 years 6 months 25 days    
Aggregate intrinsic value      
Aggregate intrinsic value, outstanding beginning balance $ 9,331    
Aggregate intrinsic value, outstanding ending balance 296 $ 9,331  
Aggregate intrinsic value, Nonvested at September 30, 2022 222    
Aggregate intrinsic value, Exercisable $ 74