Summary of Significant Accounting Policies and Select Balance Sheet Information - Summary of Prepaids and Other Current Assets (Detail) - USD ($) $ in Thousands	Sep. 30, 2022	Sep. 30, 2021
Prepaid Expense And Other Assets Current [Abstract]
Prepaid expenses	$ 2,570	$ 1,712
Irish research and development credits receivable	753	1,164
CARES Act employee retention credit receivable	3,441	3,577
Prepaids and other	$ 6,764	$ 6,453