2.4.0.84023 - Disclosure - Summary of Significant Accounting Policies (Details 4)truefalsefalse1false USDfalsefalse$D2013Q2http://www.sec.gov/CIK0001274792duration2013-04-01T00:00:002013-06-30T00:00:00USDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$2false USDfalsefalse$D2013Q2YTDhttp://www.sec.gov/CIK0001274792duration2013-01-01T00:00:002013-06-30T00:00:00USDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$3false USDfalsefalse$I2012http://www.sec.gov/CIK0001274792instant2012-12-31T00:00:000001-01-01T00:00:00USDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$4false USDtruefalse$D2013Q1_M02_SilverCreekPharmaceuticalsIncMember_ConvertibleNotesPayableMemberhttp://www.sec.gov/CIK0001274792duration2013-02-01T00:00:002013-02-28T00:00:00falsefalseSilver Creek Convertible Noteus-gaap_DebtInstrumentAxisxbrldihttp://xbrl.org/2006/xbrldius-gaap_ConvertibleNotesPayableMemberus-gaap_DebtInstrumentAxisexplicitMemberfalsefalseSilver Creekdei_LegalEntityAxisxbrldihttp://xbrl.org/2006/xbrldimack_SilverCreekPharmaceuticalsIncMemberdei_LegalEntityAxisexplicitMemberUSDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$5false USDtruefalse$D2012Q4_M12_SilverCreekPharmaceuticalsIncMember_ConvertibleNotesPayableMemberhttp://www.sec.gov/CIK0001274792duration2012-12-01T00:00:002012-12-31T00:00:00falsefalseSilver Creek Convertible Noteus-gaap_DebtInstrumentAxisxbrldihttp://xbrl.org/2006/xbrldius-gaap_ConvertibleNotesPayableMemberus-gaap_DebtInstrumentAxisexplicitMemberfalsefalseSilver Creekdei_LegalEntityAxisxbrldihttp://xbrl.org/2006/xbrldimack_SilverCreekPharmaceuticalsIncMemberdei_LegalEntityAxisexplicitMemberUSDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$6false USDtruefalse$I2013Q2_SilverCreekPharmaceuticalsIncMember_ConvertibleNotesPayableMemberhttp://www.sec.gov/CIK0001274792instant2013-06-30T00:00:000001-01-01T00:00:00falsefalseSilver Creek Convertible Noteus-gaap_DebtInstrumentAxisxbrldihttp://xbrl.org/2006/xbrldius-gaap_ConvertibleNotesPayableMemberus-gaap_DebtInstrumentAxisexplicitMemberfalsefalseSilver Creekdei_LegalEntityAxisxbrldihttp://xbrl.org/2006/xbrldimack_SilverCreekPharmaceuticalsIncMemberdei_LegalEntityAxisexplicitMemberUSDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$1true 3us-gaap_DerivativeLineItemsus-gaap_truenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4falsefalsefalse00falsefalsefalse5falsefalsefalse00falsefalsefalse6falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0Summary of significant accounting policies2false 4us-gaap_DebtInstrumentIncreaseAdditionalBorrowingsus-gaap_truecreditdurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4truefalsefalse300000300000USD$falsetruefalse5truefalsefalse16000001600000USD$falsetruefalse6falsefalsefalse00falsefalsefalsexbrli:monetaryItemTypemonetaryIncrease of additional borrowings on existing and new debt instruments.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.(f)) -URI http://asc.fasb.org/extlink&oid=6881521&loc=d3e23780-122690 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 08 -Paragraph f -Article 4 false2Aggregate principal amounts3false 4us-gaap_EmbeddedDerivativeFairValueOfEmbeddedDerivativeLiabilityus-gaap_truecreditinstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3truefalsefalse196000196000falsefalsefalse4falsefalsefalse00falsefalsefalse5truefalsefalse196000196000falsefalsefalse6truefalsefalse231000231000falsefalsefalsexbrli:monetaryItemTypemonetaryFair value as of the balance sheet date of the embedded derivative or group of embedded derivatives classified as a liability.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 133 -Paragraph 12-16, 44A, 44B -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 133 -Paragraph 44A -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 133 -Paragraph 44A, 44B -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 133 -Paragraph 44B -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4B -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=7476318&loc=SL5624163-113959 false2Derivative liability4false 2mack_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTaxmack_falsedebitdurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse00USD$falsetruefalse2truefalsefalse00USD$falsetruefalse3falsefalsefalse00falsefalsefalse4falsefalsefalse00falsefalsefalse5falsefalsefalse00falsefalsefalse6falsefalsefalse00falsefalsefalsexbrli:monetaryItemTypemonetaryAmount, after tax, of reclassification adjustments of other comprehensive income (loss).No definition available.false2Amounts reclassified out of accumulated other comprehensive incomefalseSummary of Significant Accounting Policies (Details 4) (USD $)NoRoundingUnKnownUnKnownUnKnowntruefalsefalseSheethttp://www.merrimackpharma.com/role/DisclosureSummaryOfSignificantAccountingPoliciesDetails464