XML 42 R1.htm IDEA: XBRL DOCUMENT v2.4.0.8
Document and Entity Information (USD $)
 12 Months Ended
Dec. 31, 2013
Mar. 17, 2014
Jun. 28, 2013
Document Information [Line Items]      
Entity Registrant Name ARCA Biopharma, Inc.    
Entity Central Index Key 0000907654    
Document Type 10-K    
Amendment Flag false    
Document Period End Date Dec. 31, 2013    
Document Fiscal Period Focus FY    
Document Fiscal Year Focus 2013    
Current Fiscal Year End Date --12-31    
Entity Well-known Seasoned Issuer No    
Entity Voluntary Filers No    
Entity Current Reporting Status Yes    
Entity Filer Category Smaller Reporting Company    
Entity Public Float     $ 12,057,265
Entity Common Stock, Shares Outstanding   20,979,840