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Milestone payment received.

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Amount, after allowance for credit loss, of right to consideration in exchange for good or service transferred to customer when right is conditioned on something other than passage of time, classified as current.

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Amount, excluding tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value added and excise.

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Collaboration and License Agreements - Amgen, Inc. (Details) $ in Thousands		12 Months Ended
	Sep. 28, 2016 USD ($) agreement	Sep. 30, 2022 USD ($)	Sep. 30, 2021 USD ($)	Sep. 30, 2020 USD ($)	Jul. 31, 2020 USD ($)
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Proceeds from the issuance of common stock		$ 0	$ 0	$ 250,479
Revenues		243,231	138,287	$ 87,992
Contract liabilities		74,099	111,055
Amgen \| Collaboration and License agreements
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Number of agreements \| agreement	2
Amgen \| Olpasiran Agreement
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Cash received as due under collaboration agreement	$ 35,000
Proceeds from the issuance of common stock	21,500
Milestone payments	$ 30,000
Amgen \| Olpasiran Agreement \| Maximum
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Additional remaining development regulatory and sales milestones payments		400,000
Amgen \| Olpasiran and ARO-AMG1 Agreement
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Milestone payments					$ 20,000
Revenues		0	$ 0
Contract liabilities		0
Contract assets		$ 0