Class of warrant or right exercisable expiration date.

No definition available.

Name:	abio_ClassOfWarrantOrRightExercisableExpirationDate
Namespace Prefix:	abio_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- 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

- Definition

Date the warrants or rights are exercisable, in CCYY-MM-DD format.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 235

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.4-08.(i)(3))

-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

+ Details

Name:	us-gaap_ClassOfWarrantOrRighstDateFromWhichWarrantsOrRightsExercisable
Namespace Prefix:	us-gaap_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

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

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 235

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.4-08.(i)(4))

-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

+ Details

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

- 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/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 235

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.4-08.(i)(2))

-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

+ Details

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

- 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://www.xbrl.org/2003/role/presentationRef

-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=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 30

-Article 5

+ Details

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

- Definition

The cash inflow from the issuance of common stock, preferred stock, treasury stock, stock options, and other types of equity.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Financing Activities

-URI http://asc.fasb.org/extlink&oid=6513228

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 14

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=56944662&loc=d3e3255-108585

+ Details

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

- Definition

Per share or per unit amount of equity securities issued.

+ References

No definition available.

+ Details

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

- Details

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

- Details

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

- Details

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

Equity Financings and Warrants (Details Textual) - USD ($) $ / shares in Units, $ in Millions			9 Months Ended
	Jun. 16, 2015	Feb. 07, 2014	Sep. 30, 2015	Dec. 31, 2014	Feb. 03, 2014
Equity Financing And Warrants [Line Items]
Common stock, shares issued			9,049,789	3,021,498
Private Investment In Public Entity Transaction
Equity Financing And Warrants [Line Items]
Common stock, shares issued	6,003,082
Warrants available to purchase additional commons shares	2,401,233
Purchase price for common stock unit	$ 6.1635
Proceeds from the issuance of security units	$ 34.2
Warrants will become exercisable date			Dec. 13, 2015
Warrants were exercisable upon issuance, expiry date			Jun. 16, 2022
Warrant price per share	$ 6.1012
Private Investment In Public Entity Transaction \| Security Units
Equity Financing And Warrants [Line Items]
Common stock, shares issued	6,003,082
Registered Direct Offering
Equity Financing And Warrants [Line Items]
Common stock, shares issued		730,890
Warrants available to purchase additional commons shares		182,722
Purchase price for common stock unit		$ 11.90
Proceeds from the issuance of security units		$ 7.9
Warrants were exercisable upon issuance, expiry date			Feb. 07, 2019
Warrant price per share					$ 14.875