Fair Value of Financial Assets and Liabilities - Rollforward of Aggregate Fair Values of Outstanding Series 1 Nonconvertible Preferred Stock (Detail) - Series 1 Nonconvertible Preferred Stock [Member] $ in Thousands	9 Months Ended
	Jun. 30, 2022 USD ($)
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance	$ 1,506
Change in fair value of nonconvertible preferred stock	0
Ending Balance	$ 1,506