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Fair Value Disclosures (Details) (USD $)	3 Months Ended	6 Months Ended
	Jun. 30, 2014	Jun. 30, 2014
Fair Value Disclosures (Textual) [Abstract]
Transfers of assets between fair value hierarchy levels	$ 0	$ 0
Money Market Funds
Fair Value Disclosures (Textual) [Abstract]
Cash equivalents consisting of money market funds	$ 19,000,000	$ 19,000,000
Maximum
Fair Value Disclosures (Textual) [Abstract]
Cash equivalents consisting of money market funds, maturity period		90 days

X

- Definition

Cash equivalents consisting of money market funds maturity period.

+ References

No definition available.

+ Details

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X

- Definition

Fair value assets between hierarchy levels transfers amount.

+ References

No definition available.

+ Details

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

X

- Details

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Namespace Prefix:	abio_
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X

- Definition

Fair value portion of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Cash

-URI http://asc.fasb.org/extlink&oid=6506951



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

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Cash Equivalents

-URI http://asc.fasb.org/extlink&oid=6507016

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