Collaborative Arrangement - Additional Information (Detail) - USD ($)	12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Deferred revenue, current portion		$ 9,646,000
Long-term deferred revenue		11,247,000
Abbott [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Upfront fee received	$ 25,000,000	25,000,000
Collaborative arrangement milestone payment received	10,000,000
Collaboration revenue recognized	13,500,000	$ 4,400,000
Proceeds from collaborative arrangement	35,000,000
Collaborative arrangement revenue recognized from milestone	5,100,000
Collaborative arrangement revenue recognized from milestone related to proportional performance	1,700,000
Collaboration revenue unrecognized	35,000,000
Deferred revenue, current portion	5,500,000
Long-term deferred revenue	11,600,000
Abbott [Member] | Maximum [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Collaborative arrangement additional potential milestone payments receivable	$ 57,000,000