Stockholders' Equity - Quantities and Average Prices of Shares Issued Under the ESPP (Details) - Employee Stock Purchase Plan - $ / shares	12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares issued under the ESPP	88,625	80,417	44,172
Average price of shares issued	$ 20.58	$ 28.18	$ 73.40