Basis of Presentation - Additional Information (Detail) - USD ($)	3 Months Ended		9 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Oct. 01, 2019
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Revenue	$ 24,344,000	$ 22,227,000	$ 69,261,000	$ 58,298,000
Income tax benefit	(260,000)	$ (2,613,000)	(598,000)	$ (2,799,000)
Deferred rent liability	1,200,000		1,200,000
ASC Topic 842 [Member] | Scenario Forecast [Member]
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Right of use asset					$ 1,700,000
Lease obligation liability					$ 2,900,000
Impact of Adoption [Member] | Adoption of ASC Topic 606 [Member]
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Revenue	$ 1,200,000		$ 1,300,000
Type of Revenue [Extensible List]	us-gaap:RoyaltyMember		us-gaap:RoyaltyMember
Impact of Adoption [Member] | Adoption of ASC Topic 606 [Member] | Maximum [Member]
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Income tax benefit	$ 300,000		$ 300,000