XML 123 R40.htm IDEA: XBRL DOCUMENT
v3.24.1.1.u2

Income Taxes (Details) - USD ($) | 12 Months Ended |
--- | --- | ---
Dec. 31, 2023 | Dec. 31, 2022 | Dec. 31, 2017 | Mar. 31, 2024
Income Taxes (Details) [Line Items] |  |  |  |
Net operating loss carryforwards | $ 208,100,000 |  |  |
Operating loss carryforwards, limitations on use | The net operating loss carryforwards beginning in 2018, have no expiration. |  |  |
Valuation allowance | $ 55,500,000 |  |  |
Increase in net deferred tax assets and liabilities | $ 1,200,000 |  |  |
Federal statutory income tax rate | 21.00% | 21.00% |  |
Open Tax Year | 2009 |  |  |
Reserve for uncertain tax positions | $ 0 | $ 0 |  |
Interest or penalties recognized | 0 | $ 0 |  |
Research Tax Credit Carryforward |  |  |  |
Income Taxes (Details) [Line Items] |  |  |  |
Research and experimentation credits | $ 2,400,000 |  |  |
Tax credit carryforward, limitations on use | Utilization of net operating losses and tax credits, including those acquired as a result of the Merger, will be subject to an annual limitation due to ownership change limitations provided by Internal Revenue Code Section 382. ARCA believes that an ownership change limitation as defined under Section 382 of the U.S. Internal Revenue Code occurred as a result of its various historical financing transactions. Future utilization of the federal net operating losses and tax credit carryforwards accumulated from June 2005 to the change in ownership date will be subject to annual limitations to offset future taxable income. The annual limitation may result in the expiration of the net operating losses and credits before utilization. As such, a portion of ARCA’s net operating loss carryforwards may be limited. |  |  |
Earliest Tax Year |  |  |  |
Income Taxes (Details) [Line Items] |  |  |  |
Operating loss carryforwards expiration year |  |  | 2025 |
Latest Tax Year |  |  |  |
Income Taxes (Details) [Line Items] |  |  |  |
Operating loss carryforwards expiration year |  |  | 2037 |

X
- Definition Deferred tax assets and liabilities valuation allowance. + References No definition available. + Details
Name: | abio_DeferredTaxAssetsAndLiabilitiesValuationAllowance
Namespace Prefix: | abio_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- References No definition available. + Details
Name: | abio_IncomeTaxesDetailsLineItems
Namespace Prefix: | abio_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Operating loss carryforwards expiration year. + References No definition available. + Details
Name: | abio_OperatingLossCarryforwardsExpirationYear
Namespace Prefix: | abio_
Data Type: | xbrli:gYearItemType
Balance Type: | na
Period Type: | duration

X
- Definition Valuation allowance deferred tax assets and liabilities change in amount. + References No definition available. + Details
Name: | abio_ValuationAllowanceDeferredTaxAssetsAndLiabilitiesChangeInAmount
Namespace Prefix: | abio_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Percentage of domestic federal statutory tax rate applicable to pretax income (loss). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 235 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.4-08(h)(2)) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480678/235-10-S99-1 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 740 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 12 -Publisher FASB -URI https://asc.fasb.org//1943274/2147482685/740-10-50-12 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 740 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SAB Topic 6.I.Fact.4) -Publisher FASB -URI https://asc.fasb.org//1943274/2147479360/740-10-S99-1 + Details
Name: | us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition The sum of the amounts of estimated penalties and interest recognized in the period arising from income tax examinations. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 740 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 15 -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org//1943274/2147482685/740-10-50-15 + Details
Name: | us-gaap_IncomeTaxExaminationPenaltiesAndInterestExpense
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount recognized for uncertainty in income taxes classified as current. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.20) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480566/210-10-S99-1 + Details
Name: | us-gaap_LiabilityForUncertainTaxPositionsCurrent
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Tax year that remains open to examination under enacted tax laws, in YYYY format. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 740 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 15 -Subparagraph (e) -Publisher FASB -URI https://asc.fasb.org//1943274/2147482685/740-10-50-15 + Details
Name: | us-gaap_OpenTaxYear
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:gYearListItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of operating loss carryforward, before tax effects, available to reduce future taxable income under enacted tax laws. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 3 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org//1943274/2147482685/740-10-50-3 + Details
Name: | us-gaap_OperatingLossCarryforwards
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition The amount of the tax credit carryforward, before tax effects, available to reduce future taxable income under enacted tax laws. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 3 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org//1943274/2147482685/740-10-50-3 + Details
Name: | us-gaap_TaxCreditCarryforwardAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition A description of the origin, nature, and characteristics of the tax credit carryforward. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 3 -Publisher FASB -URI https://asc.fasb.org//1943274/2147482685/740-10-50-3 + Details
Name: | us-gaap_TaxCreditCarryforwardDescription
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Description of the limitation related to use of the tax credit carryforward. + References No definition available. + Details
Name: | us-gaap_TaxCreditCarryforwardLimitationsOnUse
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_TaxCreditCarryforwardAxis=us-gaap_ResearchMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_TaxPeriodAxis=us-gaap_EarliestTaxYearMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_TaxPeriodAxis=us-gaap_LatestTaxYearMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |