Commitments and Contingencies - Additional Information (Detail)	3 Months Ended		9 Months Ended
	Jun. 30, 2017 USD ($) ft²	Jun. 30, 2016 USD ($)	Jun. 30, 2017 USD ($) ft²	Jun. 30, 2016 USD ($)
Other Commitments [Line Items]
Facility rent expense	$ 328,600	$ 232,000	$ 1,126,500	$ 659,000
Provision for recorded liabilities	0		0
Future commitments	14,300,000		14,300,000
Commitments expected to be incurred in fiscal 2017	5,000,000		5,000,000
Commitments expected to be incurred beyond fiscal 2017	9,300,000		9,300,000
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
Secondary tenant improvement allowance accounted for as note payable	2,700,000		2,700,000
Rental expense including common area maintenance and real estate taxes and payments of principal and interest on the note payable			$ 180,200
Percentage of increase in annual rental cost excluding principal and interest on the note payable			2.50%
Promissory note payable	$ 2,700,000		$ 2,700,000
Promissory notes payable amortized term			10 years
Promissory note commencement date			Oct. 01, 2016
Promissory note interest rate			7.10%
Research Facility in Middleton
Other Commitments [Line Items]
Operating lease expiration month and year			2016-12
Rental expense			$ 14,000
Other rental expenses including common area maintenance and real estate taxes			$ 4,000