v3.26.1
Stock-Based Awards - Summary of Stock Option Activity Including Aggregate Intrinsic Value (Detail)
$ / shares in Units, shares in Thousands, $ in Thousands
6 Months Ended 12 Months Ended
Mar. 31, 2026
USD ($)
$ / shares
shares
Sep. 30, 2025
USD ($)
$ / shares
shares
Options    
Outstanding as of beginning of period | shares 5,759  
Granted | shares 1,273  
Exercised | shares (21)  
Forfeited | shares (13)  
Expired | shares (258)  
Outstanding as of end of period | shares 6,740 5,759
Options vested and expected to vest as of end of period | shares 6,740  
Options exercisable as of end of period | shares 4,245  
Weighted Average Exercise Price    
Outstanding | $ / shares $ 36.31  
Granted | $ / shares 13.71  
Exercised | $ / shares 8.93  
Forfeited | $ / shares 27.87  
Expired | $ / shares 34.56  
Outstanding | $ / shares 32.21 $ 36.31
Options vested and expected to vest as of end of period | $ / shares 32.21  
Options exercisable as of end of period | $ / shares $ 43.44  
Weighted Average Remaining Contractual Term    
Outstanding as of end of period 6 years 6 months 6 years
Options vested and expected to vest as of end period 6 years 6 months  
Options exercisable as of end of period 5 years 1 month 6 days  
Aggregate Intrinsic Value    
Aggregate Intrinsic Value | $ $ 7,691 $ 6,457
Options vested and expected to vest as of end of period | $ 7,691  
Options exercisable as of end of period | $ $ 3,581