Name:	abio_IncreaseOfRetentionBonusToEachExecutive
Namespace Prefix:	abio_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Initially specified percentage for beneficial number of shares

+ References

No definition available.

+ Details

Name:	abio_InitiallySpecifiedPercentageForBeneficialNumberOfShares
Namespace Prefix:	abio_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Minimum percentage of originally issued outstanding

+ References

No definition available.

+ Details

Name:	abio_MinimumPercentageOfOriginallyIssuedOutstanding
Namespace Prefix:	abio_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Minimum percentage of originally issued shares

+ References

No definition available.

+ Details

Name:	abio_MinimumPercentageOfOriginallyIssuedShares
Namespace Prefix:	abio_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Number of consecutive trading days.

+ References

No definition available.

+ Details

Name:	abio_NumberOfConsecutiveTradingDays
Namespace Prefix:	abio_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of months base salary

+ References

No definition available.

+ Details

Name:	abio_NumberOfMonthsBaseSalary
Namespace Prefix:	abio_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Payment of other party termination fee

+ References

No definition available.

+ Details

Name:	abio_PaymentOfOtherPartyTerminationFee
Namespace Prefix:	abio_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Retention bonuses.

+ References

No definition available.

+ Details

Name:	abio_RetentionBonuses
Namespace Prefix:	abio_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Subscription agreement receipt amount

+ References

No definition available.

+ Details

Name:	abio_SubscriptionAgreementReceiptAmount
Namespace Prefix:	abio_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Threshold amount after cash dividend declared.

+ References

No definition available.

+ Details

Name:	abio_ThresholdAmountAfterCashDividendDeclared
Namespace Prefix:	abio_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Threshold amount of adjusted exchange ratio.

+ References

No definition available.

+ Details

Name:	abio_ThresholdAmountOfAdjustedExchangeRatio
Namespace Prefix:	abio_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Threshold amount of declared cash dividend.

+ References

No definition available.

+ Details

Name:	abio_ThresholdAmountOfDeclaredCashDividend
Namespace Prefix:	abio_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 808
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479402/808-10-50-1

+ Details

Name:	us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The equity interest of noncontrolling shareholders, partners or other equity holders in consolidated entity.

+ References

No definition available.

+ Details

Name:	us-gaap_MinorityInterestOwnershipPercentageByNoncontrollingOwners
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

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

+ References

No definition available.

+ Details

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

- Definition

Number of common shares issuable upon conversion of preferred stock.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481112/505-10-50-13

+ Details

Name:	us-gaap_PreferredStockConvertibleSharesIssuable
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

Face amount or stated value per share of preferred stock nonredeemable or redeemable solely at the option of the issuer.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(28))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481112/505-10-50-13

+ Details

Name:	us-gaap_PreferredStockParOrStatedValuePerShare
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:perShareItemType
Balance Type:	na
Period Type:	instant

- Details

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

- Details

Name:	us-gaap_StatementClassOfStockAxis=us-gaap_SeriesBPreferredStockMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_TypeOfArrangementAxis=abio_MergerAgreementMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_TypeOfArrangementAxis=abio_SeperationAgreementMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_TypeOfArrangementAxis=abio_SecondAmendmentOfCertainRetentionBonusLettersMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_TitleOfIndividualAxis=srt_PresidentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_TitleOfIndividualAxis=srt_ChiefFinancialOfficerMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_TypeOfArrangementAxis=abio_OriginalTermsOfRetentionBonusLetterAndFirstAmendmentToRetentionBonusLetterMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_TitleOfIndividualAxis=abio_ThomasAKeuerAndCJeffreyDekkerMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

Name:	us-gaap_StatementEquityComponentsAxis=abio_CommonStockAndPreFundedWarrantsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_TypeOfArrangementAxis=abio_FirstMergerMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

Name:	us-gaap_StatementEquityComponentsAxis=us-gaap_CommonStockMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Merger Agreement - Additional Information (Details Textual)	Apr. 20, 2024 USD ($)	Apr. 03, 2024 USD ($) Member $ / shares shares	Jun. 30, 2024 USD ($)
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Declared cash dividend		$ 5,000,000
Amount after cash dividend declared		$ 20,000,000
Amount of retention bonuses			$ 444,000
ARCA and Oruka
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Percentage of ownership interest		97.61%
Series B Preferred Stock
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Minimum percentage of originally issued shares		30.00%
Minimum percentage of originally issued outstanding		30.00%
Merger Agreement \| ARCA and Oruka
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Payment of other party termination fee		$ 440,000
Merger Agreement \| Minimum
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Subscription agreement receipt of proceeds amount		$ 175,000,000
Merger Agreement \| Series B Preferred Stock
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Preferred stock, par value \| $ / shares		$ 0.001
Seperation Agreement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Number of months base salary		12 months
Cash payment		$ 25,000
Second Amendment of Certain Retention Bonus Letters \| Thomas A. Keuer
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Increase of retention bonus to each executive	$ 200,000
Second Amendment of Certain Retention Bonus Letters \| C. Jeffrey Dekker
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Increase of retention bonus to each executive	200,000
Original Terms of Retention Bonus Letter and First Amendment to Retention Bonus Letter \| Thomas A. Keuer and C. Jeffrey Dekker
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Amount of retention bonuses	$ 165,000
Oruka Therapeutics Inc \| Common Stock and Pre Funded Warrants
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Aggregate purchase price		$ 275,000,000
Oruka Therapeutics Inc \| First Merger
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Excepted number of board members \| Member		6
ARCA
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Number of consecutive trading days		5 days
Adjusted exchange ratio		$ 5,000,000
ARCA \| Common Stock
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Initially specified percentage for beneficial number of shares		9.99%
ARCA \| ARCA and Oruka
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Percentage of noncontrolling ownership interest		2.39%
ARCA \| First Merger \| Series B Preferred Stock \| Common Stock
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Preferred stock convertible shares issuable \| shares		1,000