Income Taxes - Schedule of Income Taxes from Continuing Operations Before Income Tax Benefit (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Current income tax provision (benefit):
U.S. federal	$ (1)	$ 0
U.S. state and local	8	19
Non-U.S.	59	192
Total current tax provision	66	211
Deferred income tax provision (benefit):
U.S. federal	10	10
U.S. state and local	(2)	1
Non-U.S.	(1,296)	(433)
Total deferred tax benefit	(1,288)	(422)
Income tax benefit	$ (1,222)	$ (211)