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v3.21.2

Commitments and Contingencies - Additional Information (Detail) - USD ($) | 12 Months Ended
--- | ---
Sep. 30, 2021 | Sep. 30, 2020 | Sep. 30, 2019
Other Commitments [Line Items] |  |  |
Contingent liabilities | $ 0 |  |
Technology License Commitments |  |  |
Other Commitments [Line Items] |  |  |
Milestone payments | $ 0 |  | $ 0
Technology License Commitments | ARO-ENaC and ARO-HIF2 Candidates |  |  |
Other Commitments [Line Items] |  |  |
Milestone payments |  | $ 2,400,000 |

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- Definition Amount of loss contingency liability. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 450 -SubTopic 20 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=121557415&loc=d3e14326-108349 + Details
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