Commitments and Contingencies - Additional Information (Detail)	1 Months Ended	12 Months Ended
	Apr. 30, 2019 USD ($) ft²	Sep. 30, 2019 USD ($) ft²	Sep. 30, 2018 USD ($)	Sep. 30, 2017 USD ($)	Jan. 31, 2019 ft²	Oct. 31, 2018 USD ($)
Other Commitments [Line Items]
Estimated lease payments		$ 22,385,552
Facility rent expense		1,654,800	$ 1,288,000	$ 1,441,000
Future commitments		60,200,000
Commitments expected to be incurred in fiscal 2019		50,900,000
Commitments expected to be incurred beyond fiscal 2019		9,300,000
Technology License Commitments
Other Commitments [Line Items]
Milestone payments		0	$ 0	$ 0
Corporate Headquarters In Pasadena | California
Other Commitments [Line Items]
Rental expense		$ 65,700
Percentage of increase in annual rental cost		3.00%
Corporate Headquarters In Pasadena | Colorado Owner, LLC | California
Other Commitments [Line Items]
Lease term	91 months
Office space leases, in square feet | ft²	24,000
Lease payments, commencement date	Sep. 30, 2019
Estimated lease payments	$ 8,800,000
Expected leasehold improvements, net of tenant improvement allowances	$ 3,500,000
Research Facility in Madison | Wisconsin
Other Commitments [Line Items]
Office space leases, in square feet | ft²		61,000			13,000
Rental expense		$ 135,800
Percentage of increase in annual rental cost		2.50%
Operating lease expiration month and year		2029-09
Primary tenant improvement allowance accounted for as deferred rent		$ 2,100,000
Promissory note payable		$ 2,700,000				$ 2,300,000