v3.26.1
Fair Value Measurements - Schedule of Fair Value Measurements for Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) - USD ($)
$ in Thousands
Jun. 30, 2026
Sep. 30, 2025
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Available-for-sale securities $ 1,547,201 $ 692,818
Cash equivalents 32,221 218,000
Total financial assets 1,579,422 910,818
Money market instruments    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Cash equivalents 15,635 64,460
Term deposit    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Cash equivalents 16,586 134,357
Certificate of deposits    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Cash equivalents   3,001
Corporate debt securities    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Cash equivalents   16,182
U.S. government and agency securities    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Available-for-sale securities 251,437 150,695
Certificate of deposits    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Available-for-sale securities   12,019
Municipal securities    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Available-for-sale securities   7,046
Commercial notes    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Available-for-sale securities 111,916 13,801
Corporate debt securities    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Available-for-sale securities 1,183,848 509,257
Level 1    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Available-for-sale securities 0 0
Cash equivalents 15,635 64,460
Total financial assets 15,635 64,460
Level 1 | Money market instruments    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Cash equivalents 15,635 64,460
Level 1 | Term deposit    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Cash equivalents 0 0
Level 1 | Certificate of deposits    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Cash equivalents   0
Level 1 | Corporate debt securities    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Cash equivalents   0
Level 1 | U.S. government and agency securities    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Available-for-sale securities 0 0
Level 1 | Certificate of deposits    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Available-for-sale securities   0
Level 1 | Municipal securities    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Available-for-sale securities   0
Level 1 | Commercial notes    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Available-for-sale securities 0 0
Level 1 | Corporate debt securities    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Available-for-sale securities 0 0
Level 2    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Available-for-sale securities 1,547,201 692,818
Cash equivalents 16,586 153,540
Total financial assets 1,563,787 846,358
Level 2 | Money market instruments    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Cash equivalents 0 0
Level 2 | Term deposit    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Cash equivalents 16,586 134,357
Level 2 | Certificate of deposits    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Cash equivalents   3,001
Level 2 | Corporate debt securities    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Cash equivalents   16,182
Level 2 | U.S. government and agency securities    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Available-for-sale securities 251,437 150,695
Level 2 | Certificate of deposits    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Available-for-sale securities   12,019
Level 2 | Municipal securities    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Available-for-sale securities   7,046
Level 2 | Commercial notes    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Available-for-sale securities 111,916 13,801
Level 2 | Corporate debt securities    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Available-for-sale securities 1,183,848 509,257
Level 3    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Available-for-sale securities 0 0
Cash equivalents 0 0
Total financial assets 0 0
Level 3 | Money market instruments    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Cash equivalents 0 0
Level 3 | Term deposit    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Cash equivalents 0 0
Level 3 | Certificate of deposits    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Cash equivalents   0
Level 3 | Corporate debt securities    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Cash equivalents   0
Level 3 | U.S. government and agency securities    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Available-for-sale securities 0 0
Level 3 | Certificate of deposits    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Available-for-sale securities   0
Level 3 | Municipal securities    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Available-for-sale securities   0
Level 3 | Commercial notes    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Available-for-sale securities 0 0
Level 3 | Corporate debt securities    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Available-for-sale securities $ 0 $ 0