Income Taxes - Income Tax Benefit from Continuing Operations (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Income Tax Disclosure [Abstract]
Income (loss) before income tax benefit	$ (1,965)	$ 8,980
Income tax provision (benefit) at U.S. federal statutory rates	(413)	1,886
Tax effect of:
Foreign rate differential	(193)	0
State and local income taxes	6	20
Federal tax credits	(145)	(135)
Valuation allowance	601	(2,025)
Prior year tax adjustments	(1,115)	0
Other	37	43
Income tax benefit	$ (1,222)	$ (211)