2.4.0.84050 - Disclosure - Lease Termination Costs (Details)truefalsefalse1false falsefalseD2013Q2YTDhttp://www.sec.gov/CIK0001171014duration2013-01-01T00:00:002013-07-01T00:00:00PureStandardhttp://www.xbrl.org/2003/instancepurexbrli02false falsefalseD2012Q2YTDhttp://www.sec.gov/CIK0001171014duration2012-01-03T00:00:002012-07-02T00:00:00PureStandardhttp://www.xbrl.org/2003/instancepurexbrli01true 1cosi_LeaseTerminationCostsDisclosureAbstractcosi_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0Lease Termination Costs2false 2cosi_NumberOfLocationsClosedForWhichLeaseTerminationCostsWereIncurredcosi_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse33falsefalsefalse2truefalsefalse11falsefalsefalsexbrli:integerItemTypeintegerRepresents the number of locations closed, for which lease termination costs were incurred.No definition available.false0Number of locations closed, for which lease termination costs were incurredfalseLease Termination Costs (Details)UnKnownUnKnownUnKnownUnKnowntruefalsefalseSheethttp://www.getcosi.com/role/DisclosureLeaseTerminationCostsDetails22