Subsequent Events - Additional Information (Details) - Subsequent Events - USD ($)	Aug. 06, 2021	Jul. 02, 2021
Subsequent Event [Line Items]
Sale of common stock maximum aggregate offering price		$ 150,000,000.0
Termination notice period for sales agreement		10 days
Proceeds from issuance of common stock		$ 0
Follow-on Public Offering \| Common Stock
Subsequent Event [Line Items]
Sale of stock number of shares issued in transaction	9,200,000
Sale of stock, price per share	$ 18.00
Proceeds from the follow-on public offering, net of underwriting discounts, commissions and offering costs	$ 155,300,000

Proceeds from issuance of follow on public offering.

No definition available.

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Namespace Prefix:	rna_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Sale of common stock maximum aggregate offering price.

+ References

No definition available.

+ Details

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Namespace Prefix:	rna_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Termination notice period for sales agreement.

+ References

No definition available.

+ Details

Name:	rna_TerminationNoticePeriodForSalesAgreement
Namespace Prefix:	rna_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

The cash inflow from the additional capital contribution to the entity.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 14
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3255-108585

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The number of shares issued or sold by the subsidiary or equity method investee per stock transaction.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

Per share amount received by subsidiary or equity investee for each share of common stock issued or sold in the stock transaction.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant

- Definition

Detail information of subsequent event by type. User is expected to use existing line items from elsewhere in the taxonomy as the primary line items for this disclosure, which is further associated with dimension and member elements pertaining to a subsequent event.

+ References

No definition available.

+ Details

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- Details

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- Details

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Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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