Name:	akca_AdditionalSharesIssuedAsPaymentOfRegulatoryMilestone
Namespace Prefix:	akca_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- References

No definition available.

Name:	akca_CollaborativeArrangementAndLicensingAgreementAbstract
Namespace Prefix:	akca_
Data Type:	xbrli:stringItemType
Balance Type:	na
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- References

No definition available.

Name:	akca_LicenseAgreementRegulatoryMilestoneAbstract
Namespace Prefix:	akca_
Data Type:	xbrli:stringItemType
Balance Type:	na
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The maximum amount of payments receivable per drug or program for regulatory milestone payments under the collaboration agreement.

No definition available.

Name:	akca_MaximumAmountOfPaymentsReceivablePerDrugOrProgramForRegulatoryMilestones
Namespace Prefix:	akca_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Period of time before collaboration partner pays royalties on net sales of product after first commercial sale in Brazil, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

No definition available.

Name:	akca_PeriodBeforeCollaborationPartnerPaysRoyaltiesOnNetSalesOfProductAfterFirstCommercialSaleInBrazil
Namespace Prefix:	akca_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

Amount of the regulatory milestone payment due to Ionis Pharmaceuticals, Inc. for TEGSEDI as a result of the marketing authorization, or MA, approval for TEGSEDI from the European Commission, or EC.

No definition available.

Name:	akca_RegulatoryMilestonePaymentDue
Namespace Prefix:	akca_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

The minimum amount of revenue recognized in Latin America by the collaboration partner before paying royalties.

No definition available.

Name:	akca_RevenueRecognizedByCollaborationPartnerInLatinAmericaBeforePayingRoyalties
Namespace Prefix:	akca_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Royalty percentage received on the net sales of each drug in Latin America from the collaboration partner under the collaboration agreement.

No definition available.

Name:	akca_RoyaltyPercentageReceivedOnNetSalesOfEachDrugInLatinAmericaFromCollaborationPartner
Namespace Prefix:	akca_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

The amount of the upfront payment expected to be received in the near term under the collaboration agreement.

No definition available.

Name:	akca_UpfrontPaymentDue
Namespace Prefix:	akca_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

The amount of the upfront payment to be paid on the earlier of approval by the U.S. Food and Drug Administration (FDA) or the European Medicines Agency (EMA) under the collaboration agreement.

No definition available.

Name:	akca_UpfrontPaymentToBePaidAfterApproval
Namespace Prefix:	akca_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

The total amount of upfront payments expected to be received under the collaboration agreement.

No definition available.

Name:	akca_UpfrontPaymentToBeReceived
Namespace Prefix:	akca_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

The parent entity's interest in net assets of the subsidiary, expressed as a percentage.

No definition available.

Name:	us-gaap_MinorityInterestOwnershipPercentageByParent
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

Name:	dei_LegalEntityAxis=akca_IonisPharmaceuticalsIncMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	srt_OwnershipAxis=akca_AkceaTherapeuticsIncMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_SubsequentEventTypeAxis=us-gaap_SubsequentEventMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: