Income Taxes - Unrecognized tax benefits (Details) - USD ($)	12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Balance at beginning of year	$ 1,856,629	$ 1,856,629
Changes based on tax positions related to the current year	0	0
Balance at end of year	$ 1,856,629	$ 1,856,629