Marketable Securities - Summary of Amortized Cost and Fair Value (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Sep. 30, 2020
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	$ 3,679	$ 3,168
Fair Value	3,679	3,168
Certificates of Deposit
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	30	51
Fair Value	30	51
Corporate securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	3,624	3,101
Fair Value	3,624	3,101
Municipal securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	25
Fair Value	$ 25
Other debt securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost		16
Fair Value		$ 16