XML 41 R31.htm IDEA: XBRL DOCUMENT v3.20.2

Equity Financings and Warrants (Details Textual) - USD ($)				1 Months Ended	6 Months Ended		12 Months Ended
	Jul. 31, 2020	Jul. 22, 2020	Jun. 03, 2020	Jul. 31, 2020	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019	Jul. 14, 2020	Jan. 11, 2017
Equity Financing And Warrants [Line Items]
Net proceeds from issuance of common stock				$ 24,100,000	$ 6,061,000	$ 6,517,000
Common stock, par value					$ 0.001		$ 0.001
Common stock, shares issued					2,267,570		1,594,070
JonesTrading
Equity Financing And Warrants [Line Items]
Percentage of selling commission per additional shares sold									3.00%
Sales Agreement
Equity Financing And Warrants [Line Items]
Common stock, shares issued					0		820,561
Net proceeds from issuance of common stock					$ 0		$ 6,900,000
Sales Agreement | Subsequent Event
Equity Financing And Warrants [Line Items]
Net proceeds from issuance of common stock				$ 14,400,000
Sale of common stock				2,214,301
Sales Agreement | JonesTrading
Equity Financing And Warrants [Line Items]
Common stock, par value									$ 0.001
Aggregate offering price of common stock authorized									$ 7,300,000
Sales Agreement | JonesTrading | Subsequent Event
Equity Financing And Warrants [Line Items]
Aggregate offering price of common stock authorized								$ 32,400,000
2020 Sales Agreement | Subsequent Event
Equity Financing And Warrants [Line Items]
Net proceeds from issuance of common stock	$ 9,700,000
Sale of common stock	1,423,413
Aggregate offering price	$ 43,900,000	$ 54,000,000
Direct Offering
Equity Financing And Warrants [Line Items]
Common stock issued			348,000
Purchase price per share			$ 9.00
Pre-funded warrants to purchase shares of common stock			325,500
Purchase price per warrant			$ 8.999
Pre-funded warrants outstanding			0
Net proceeds from issuance of common stock			$ 5,300,000
Percentage of selling commission per additional shares sold			8.00%

X

- Definition

Common stock, authorized offering amount under agreement to sell.

+ References

No definition available.

+ Details

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

X

- Definition

Equity financing and warrants.

+ References

No definition available.

+ Details

Name:	abio_EquityFinancingAndWarrantsLineItems
Namespace Prefix:	abio_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Definition

The cash inflow associated with the amount received from entity's raising of capital via registered direct offering, net of related financing costs.

+ References

No definition available.

+ Details

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

X

- Definition

Sale of common stock aggregate offering price.

+ References

No definition available.

+ Details

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

X

- Definition

Selling commission per additional shares sold percentage.

+ References

No definition available.

+ Details

Name:	abio_SellingCommissionPerAdditionalSharesSoldPercentage
Namespace Prefix:	abio_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

X

- Definition

Exercise price per share or per unit of warrants or rights outstanding.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21475-112644

+ Details

Name:	us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant

X

- Definition

Number of securities into which the class of warrant or right may be converted. For example, but not limited to, 500,000 warrants may be converted into 1,000,000 shares.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21475-112644

+ Details

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

X

- Definition

Number of warrants or rights outstanding.

+ References

No definition available.

+ Details

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

X

- Definition

Face amount or stated value per share of common stock.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(29))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

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

X

- Definition

Total number of common shares of an entity that have been sold or granted to shareholders (includes common shares that were issued, repurchased and remain in the treasury). These shares represent capital invested by the firm's shareholders and owners, and may be all or only a portion of the number of shares authorized. Shares issued include shares outstanding and shares held in the treasury.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(29))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

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

X

- 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

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

X

- 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

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

X

- Definition

Number of shares issued in lieu of cash for services contributed to the entity. Number of shares includes, but is not limited to, shares issued for services contributed by vendors and founders.

+ References

No definition available.

+ Details

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

X

- Definition

Number of new stock issued during the period.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(29))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21463-112644

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-URI http://asc.fasb.org/extlink&oid=120397183&loc=d3e187085-122770

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(28))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

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

X

- Details

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

X

- Details

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

X

- Details

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

X

- Details

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

X

- Details

Name:	us-gaap_SubsidiarySaleOfStockAxis=abio_DirectOfferingMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: