Commitments and Contingencies - Additional Information (Detail)	3 Months Ended		9 Months Ended
	Jun. 30, 2018 USD ($) ft²	Jun. 30, 2017 USD ($)	Jun. 30, 2018 USD ($) ft²	Jun. 30, 2017 USD ($)
Other Commitments [Line Items]
Facility rent expense	$ 353,400	$ 328,600	$ 1,041,400	$ 1,126,500
Provision for recorded liabilities	0		0
Future commitments	19,200,000		19,200,000
Commitments expected to be incurred in fiscal 2018	5,000,000		5,000,000
Commitments expected to be incurred beyond fiscal 2018	14,200,000		14,200,000
Technology License Commitments
Other Commitments [Line Items]
Milestone payments	$ 0	$ 0	$ 0	$ 0
Corporate Headquarters In Pasadena
Other Commitments [Line Items]
Office space leases, in square feet | ft²	8,500		8,500
Operating lease expiration month and year			2019-09
Rental expense			$ 27,000
Percentage of increase in annual rental cost			3.00%
Research Facility in Madison
Other Commitments [Line Items]
Office space leases, in square feet | ft²	60,000		60,000
Operating lease expiration month and year			2026-09
Primary tenant improvement allowance accounted for as deferred rent	$ 2,100,000		$ 2,100,000
Promissory note payable	$ 2,700,000		2,700,000
Rental expense including payments of principal and interest on the note payable			$ 182,200
Percentage of increase in annual rental cost excluding principal and interest on the note payable			2.50%
Promissory notes payable amortized term			10 years
Promissory note commencement date			Oct. 01, 2016
Promissory note interest rate			7.10%