Collaborative Arrangement - Additional Information (Detail) - USD ($)	3 Months Ended		6 Months Ended		12 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Mar. 31, 2023	Mar. 31, 2022	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2022
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Total revenue	$ 27,198,000	$ 26,106,000	$ 52,131,000	$ 49,109,000
Deferred revenue									$ 9,200,000
Abbott Agreement [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Collaborative arrangement payment received			60,800,000
Total revenue	1,300,000	$ 1,400,000	2,600,000
Collaboration revenue recognized included in balance at beginning of period			2,600,000	$ 2,600,000
Deferred revenue	6,600,000		6,600,000
Abbott Agreement [Member] | Upfront Payment [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Collaborative arrangement payment received								$ 25,000,000
Abbott Agreement [Member] | Milestone Payment [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Collaborative arrangement payment received					$ 15,000,000	$ 10,800,000	$ 10,000,000
Abbott Agreement [Member] | PMA Received After December 31, 2022 [Member] | TRANSCEND Clinical Trial [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Collaborative arrangement additional potential milestone payments receivable	$ 24,000,000		$ 24,000,000