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Commitments and Contingencies - Additional Information (Detail) | 3 Months Ended |  |
--- | --- | --- | ---
Dec. 31, 2018 USD ($) ft² | Dec. 31, 2017 USD ($) | Jan. 31, 2019 ft² | Oct. 31, 2018 USD ($)
Other Commitments [Line Items] |  |  |  |
Promissory note payable | $ 2,300,000 |  |  |
Facility rent expense | 335,000 | $ 326,000 |  |
Provision for recorded liabilities | 0 |  |  |
Future commitments | 34,000,000 |  |  |
Commitments expected to be incurred in fiscal 2019 | 25,000,000 |  |  |
Commitments expected to be incurred beyond fiscal 2019 | 9,000,000 |  |  |
Technology License Commitments |  |  |  |
Other Commitments [Line Items] |  |  |  |
Milestone payments | $ 0 | $ 0 |  |
Subsequent Event | Madison, Wisconsin Research Facility |  |  |  |
Other Commitments [Line Items] |  |  |  |
Office space leases, in square feet | ft² |  |  | 13,000 |
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 | $ 28,100 |  |  |
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 |  |  |
Promissory note payable | 2,700,000 |  |  | $ 2,300,000
Rental expense including payments of principal and interest on the note payable | $ 133,400 |  |  |
Percentage of increase in annual rental cost excluding principal and interest on the note payable | 2.50% |  |  |
Research Facility in Madison | Subsequent Event |  |  |  |
Other Commitments [Line Items] |  |  |  |
Office space leases, in square feet | ft² |  |  | 13,000 |

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