2.4.0.82410402 - Disclosure - Convertible Senior Notes Narrative (Details)truefalsefalse1false USDfalsefalseD2013Q2YTDhttp://www.sec.gov/CIK0001113481duration2013-01-01T00:00:002013-06-30T00:00:00dayStandardhttp://www.themedicinescompany.com/20130630daymdco0numberStandardhttp://www.xbrl.org/2003/instancepurexbrli0usdPerShareDividehttp://www.xbrl.org/2003/iso4217USDiso4217http://www.xbrl.org/2003/instancesharesxbrli0usdStandardhttp://www.xbrl.org/2003/iso4217USDiso42170$2false USDfalsefalse$I2012Q4http://www.sec.gov/CIK0001113481instant2012-12-31T00:00:000001-01-01T00:00:00usdStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$3false USDtruefalse$D2012Q2YTD_us-gaap_LongtermDebtTypeAxis_us-gaap_ConvertibleDebtMemberhttp://www.sec.gov/CIK0001113481duration2012-01-01T00:00:002012-06-30T00:00:00falsefalseConvertible Debt [Member]us-gaap_LongtermDebtTypeAxisxbrldihttp://xbrl.org/2006/xbrldius-gaap_ConvertibleDebtMemberus-gaap_LongtermDebtTypeAxisexplicitMemberusdStandardhttp://www.xbrl.org/2003/iso4217USDiso42170numberStandardhttp://www.xbrl.org/2003/instancepurexbrli0USDUSD$1true 3us-gaap_DebtInstrumentLineItemsus-gaap_truenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0Debt Instrument [Line Items]2false 4us-gaap_SeniorNotesus-gaap_truecreditinstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse231025000231025000USD$falsetruefalse2truefalsefalse226109000226109000USD$falsetruefalse3truefalsefalse275000000275000000USD$falsetruefalsexbrli:monetaryItemTypemonetaryIncluding the current and noncurrent portions, carrying value as of the balance sheet date of Notes with the highest claim on the assets of the issuer in case of bankruptcy or liquidation (with maturities initially due after one year or beyond the operating cycle if longer). Senior note holders are paid off in full before any payments are made to junior note holders.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03.16) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03.16(a)) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 16 -Article 9 false2Senior notes3false 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trading days to trigger conversion feature, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.No definition available.false0Consecutive trading period7false 4mdco_DebtInstrumentCovenantPercentOfConversionPricemdco_falsenainstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truetruefalse1.301.30falsefalsefalse2falsetruefalse00falsefalsefalse3falsetruefalse00falsefalsefalsenum:percentItemTypepureDebt Instrument, Covenant, Percent of Conversion PriceNo definition available.false0Percent of conversion price8false 4mdco_DebtInstrumentMeasurementPeriodmdco_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse005 daysfalsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalsexbrli:durationItemTypenaDebt Instrument, Measurement PeriodNo definition available.false0Measurement period9false 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SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 22 -Article 5 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 7 -URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21521-112644 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 6 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21506-112644 Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.22(a)(5)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 6: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Conversion Rate -URI http://asc.fasb.org/extlink&oid=6509012 false0Conversion ratio13false 4mdco_DebtInstrumentCovenantPercentOfPrincipalAmountPlusAccruedAndUnpaidInterestmdco_falsenainstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truetruefalse1.01.0falsefalsefalse2falsetruefalse00falsefalsefalse3falsetruefalse00falsefalsefalsenum:percentItemTypepureDebt Instrument, Covenant, Percent of Principal Amount, Plus Accrued and Unpaid InterestNo definition available.false0Percent of principal amount plus accrued and unpaid interest14false 4mdco_DebtInstrumentCovenantPercentOfPrincipalAmountmdco_falsenainstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truetruefalse0.250.25falsefalsefalse2falsetruefalse00falsefalsefalse3falsetruefalse00falsefalsefalsenum:percentItemTypepureDebt Instrument, Covenant, Percent of Principal AmountNo definition available.false0Percent of principal amount15false 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