Commitments and Contingencies - Additional Information (Detail)	3 Months Ended
	Dec. 31, 2016 USD ($) ft²	Dec. 31, 2015 USD ($)
Other Commitments [Line Items]
Facility rent expense	$ 381,100	$ 198,600
Provision for recorded liabilities	0
Future commitments	12,400,000
Commitments expected to be incurred in fiscal 2017	12,400,000
Commitments expected to be incurred beyond fiscal 2017	0
Technology License Commitments
Other Commitments [Line Items]
Milestone payments	$ 0	$ 0
Corporate Headquarters In Pasadena
Other Commitments [Line Items]
Office space leases, in square feet | ft²	8,500
Operating lease expiration month and year	2019-09
Rental expense	$ 26,000
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
Operating lease expiration month and year	2026-09
Primary tenant improvement allowance accounted for as deferred rent	$ 2,100,000
Secondary tenant improvement allowance accounted for as note payable	2,700,000
Rental expense including payments of principal and interest on the note payable	180,100
Promissory note payable	$ 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