Summary of Significant Accounting Policies and Select Balance Sheet Information - Additional Information (Detail) - USD ($) shares in Millions	12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019	Oct. 01, 2019
Summary Of Significant Accounting Policies [Line Items]
Held-to-maturity debt securities	$ 0	$ 0
Realized gains or losses on sales of available-for-sale securities	0	0	$ 0
CARES Act employee retention credit, benefit to operating costs and expenses	3,600,000
CARES Act employee retention credit receivable	3,577,000	3,600,000
Depreciation expense	4,900,000	4,800,000	4,700,000
Amortization expense	3,100,000	2,500,000	2,600,000
Impairment loss	0	0
Goodwill impairment charges	0	0	0
Impairment charges relating to long-lived assets	$ 0	$ 0	$ 0
Antidilutive options excluded from computation of EPS	0.1	0.1	0.2
ASC Topic 842 adoption, right-of-use asset	$ 2,435,000	$ 2,508,000
ASC Topic 842 adoption, lease liability	3,706,000	3,776,000
Deferred rent liability		1,200,000
ASC Topic 842 [Member]
Summary Of Significant Accounting Policies [Line Items]
ASC Topic 842 adoption, right-of-use asset				$ 1,700,000
ASC Topic 842 adoption, lease liability				$ 2,900,000
Abbott Agreement [Member]
Summary Of Significant Accounting Policies [Line Items]
Collaborative arrangement payment received	60,800,000
Collaborative arrangement additional potential milestone payments receivable	$ 30,000,000
Abbott Agreement [Member] | TRANSCEND Clinical Trial [Member]
Summary Of Significant Accounting Policies [Line Items]
Clinical study completion period	4 years
IDA [Member]
Summary Of Significant Accounting Policies [Line Items]
Reimbursement recorded as reduction to R&D expense		800,000	$ 700,000
Revenue [Member]
Summary Of Significant Accounting Policies [Line Items]
Performance obligations, payment terms, royalties	45 days
Minimum [Member] | Revenue [Member]
Summary Of Significant Accounting Policies [Line Items]
Performance obligations, payment terms, product sales	30 days
Performance obligations, payment terms, R&D services	30 days
Maximum [Member] | Revenue [Member]
Summary Of Significant Accounting Policies [Line Items]
Performance obligations, payment terms, product sales	45 days
Performance obligations, payment terms, R&D services	45 days
Leases [Member]
Summary Of Significant Accounting Policies [Line Items]
Lease description	The Company leases facilities for research, office, manufacturing and warehousing.
Lease, existence of option to extend	true
Lease, option to extend	The Company’s leases include one or more options to renew and extend the lease term at the Company’s discretion. These renewal options are not included in right-of-use assets and lease liabilities as they are not reasonably certain of exercise.
Operating lease cost	$ 800,000	$ 600,000
Rent expense related to operating leases			500,000
Weighted average remaining lease term for operating leases	6 years 2 months 12 days
Weighted average discount rate used to determine operating lease liabilities	4.00%
Research and development expense [Member] | In-Process Research and Development [Member]
Summary Of Significant Accounting Policies [Line Items]
Impairment loss			$ 300,000