Commitments and Contingencies - Additional Information (Detail) - USD ($)	3 Months Ended		6 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2021	Mar. 31, 2020
Other Commitments [Line Items]
Contingent liabilities	$ 0		$ 0
Future commitments	136,000,000.0		136,000,000.0
Commitments expected to be incurred during remainder of fiscal year 2021	78,000,000.0		78,000,000.0
Technology License Commitments
Other Commitments [Line Items]
Milestone payments	$ 0	$ 900,000	$ 0	$ 900,000