Commitments and Contingencies - Additional Information (Detail)	1 Months Ended	3 Months Ended		12 Months Ended	60 Months Ended
	Jul. 31, 2019 USD ($)	Dec. 31, 2019 USD ($) € / $	Dec. 31, 2019 EUR (€)	Sep. 30, 2018 USD ($)	Sep. 30, 2024 USD ($)	Sep. 30, 2019 USD ($)
Commitments And Contingencies [Line Items]
Exchange rate relating to license payment | € / $		1.1215
Other long-term liabilities		$ 6,634,000				$ 5,512,000
Embolitech LLC [Member]
Commitments And Contingencies [Line Items]
Contingent payments upon achievement of regulatory milestones		$ 2,000,000
Installment payment beginning period		2020	2020
Installment payment ending period		2024	2024
CRO [Member]
Commitments And Contingencies [Line Items]
Contractual obligation to be paid		$ 11,900,000
CRO [Member] | Maximum [Member]
Commitments And Contingencies [Line Items]
Contractual obligations		26,000,000
Contractual obligation due in next several years		40,000,000
CRO [Member] | Minimum [Member]
Commitments And Contingencies [Line Items]
Contractual obligation due in next several years		$ 35,000,000
License [Member]
Commitments And Contingencies [Line Items]
License agreement commencement date		2006-03	2006-03
Annual minimum payments for licenses		$ 224,000	€ 200,000
Future minimum payments associated with license		$ 1,800,000
Patents [Member]
Commitments And Contingencies [Line Items]
Patent expiry date		2027-09	2027-09
Intellectual Property [Member] | Medical Device [Member]
Commitments And Contingencies [Line Items]
Payments to acquire intellectual property assets	$ 800,000
Contingent payments upon achievement of regulatory milestones	$ 1,300,000
Contingency period ending year	2022
Estimated additional payment to acquire intellectual property assets	$ 200,000
Intellectual Property [Member] | Embolitech LLC [Member]
Commitments And Contingencies [Line Items]
Payments to acquire intellectual property assets				$ 5,000,000
Contingency period ending year		2033	2033
Other accrued liabilities noncurrent		$ 1,200,000				1,000,000
Other long-term liabilities		$ 2,100,000				$ 2,100,000
Intellectual Property [Member] | Embolitech LLC [Member] | Scenario Forecast [Member]
Commitments And Contingencies [Line Items]
Estimated additional payment to acquire intellectual property assets					$ 3,500,000