Income Taxes - Summary of Effective Income Tax Rate Reconciliation (Details)	12 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2023
Income Tax Disclosure [Abstract]
U.S. federal statutory income tax	21.00%	21.00%	21.00%
State income taxes, net of federal tax benefit	(3.10%)	2.60%	0.40%
Tax credits	(44.40%)	3.00%	6.80%
Permanent and other items	(37.90%)	2.50%	(4.60%)
Non-deductible compensation	5.10%	(0.90%)	(4.60%)
Foreign-derived intangible income deduction	(16.20%)	0.00%	1.20%
Other income	11.10%	0.00%	0.00%
Stock compensation	10.70%	(0.70%)	(1.10%)
Valuation allowance	95.40%	(27.00%)	(20.50%)
Effective income tax rate	41.70%	0.50%	(1.40%)