Commitments and Contingencies - Additional Information (Detail) - USD ($)	3 Months Ended		9 Months Ended	12 Months Ended		36 Months Ended
	Dec. 31, 2020	Mar. 31, 2020	Jun. 30, 2021	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2024	Sep. 30, 2020
Commitments And Contingencies [Line Items]
Payments to acquire intangible assets			$ 1,000,000
Other accrued liabilities current			4,303,000				$ 5,547,000
Other long-term liabilities			7,670,000				8,020,000
Embolitech LLC [Member]
Commitments And Contingencies [Line Items]
Payments to acquire in-process research and development		$ 1,000,000.0			$ 5,000,000.0
Contingent payments upon achievement of regulatory milestones			$ 1,000,000.0
Installment payment beginning period			2022
Installment payment ending period			2024
CRO [Member]
Commitments And Contingencies [Line Items]
Contractual obligation remaining to be paid			$ 8,000,000
CRO [Member] | Minimum [Member]
Commitments And Contingencies [Line Items]
Gross contractual obligation			35,000,000
CRO [Member] | Maximum [Member]
Commitments And Contingencies [Line Items]
Gross contractual obligation			40,000,000
CRO [Member] | Maximum [Member] | CRO Pass-through Expenses [Member]
Commitments And Contingencies [Line Items]
Gross contractual obligation			29,000,000
Intellectual Property Assets [Member]
Commitments And Contingencies [Line Items]
Other accrued liabilities current			500,000				1,100,000
Other long-term liabilities			$ 1,800,000				$ 2,200,000
Intellectual Property Assets [Member] | Embolitech LLC [Member]
Commitments And Contingencies [Line Items]
Contingency period ending year			2033
Payments to acquire intangible assets	$ 1,000,000.0
Intellectual Property Assets [Member] | Embolitech LLC [Member] | Forecast [Member]
Commitments And Contingencies [Line Items]
Contractual obligation payable in fiscal 2022 through fiscal 2024						$ 2,500,000
Intellectual Property Assets [Member] | InnoCore Technologies BV [Member]
Commitments And Contingencies [Line Items]
License agreement commencement year			2006
Annual minimum payments for licenses			$ 200,000
Patent expiry date			2027-05
Future minimum payments associated with license			$ 1,400,000
Intellectual Property Assets [Member] | Medical Device [Member]
Commitments And Contingencies [Line Items]
Payments to acquire in-process research and development	$ 200,000			$ 800,000
Contingent payments upon achievement of regulatory milestones			$ 1,100,000
Contingency period ending year			2022