Fair Value Measurements - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impairment loss related to investments	$ 0	$ 0	$ (31,854)
Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Amount invested in non-marketable convertible note				$ 2,000
Impairment loss related to investments	$ 2,000