Summary of Significant Accounting Policies - Summary of Fair Value Estimates (Detail) - USD ($) $ in Thousands	Jun. 30, 2025	Sep. 30, 2024	Sep. 30, 2023
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment in ZEN	$ 7,096	$ 4,767	$ 4,671
Investment, Type [Extensible Enumeration]	Investment in ZEN [Member]	Investment in ZEN [Member]
Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment in ZEN	$ 7,096	$ 4,767
Investment, Type [Extensible Enumeration]	Investment in ZEN [Member]	Investment in ZEN [Member]
Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment in ZEN	$ 0	$ 0
Investment, Type [Extensible Enumeration]	Investment in ZEN [Member]	Investment in ZEN [Member]
Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment in ZEN	$ 0	$ 0
Investment, Type [Extensible Enumeration]	Investment in ZEN [Member]	Investment in ZEN [Member]