Income Taxes - Income Tax Expense (Benefit) (Details) - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Income Tax Expense (Benefit), Continuing Operations [Abstract]
Income tax expense (benefit)	$ (190)	$ (4,640)
Income tax expense for tax deductions that are lower than the associated book compensation expense	500
Income tax expense related to a valuation allowance on beginning of year deferred tax assets	700
Income tax expense related to a valuation allowance recorded against the current year deferred tax assets	$ 2,600
Deferred tax benefit resulting from the extension of a tax incentive in China		$ 1,300