Business Combination, Contingent Consideration, Number of Periods Preceding Closing of Purchase

No definition available.

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- Definition

Business Combination, Contingent Consideration, Period of Collaboration Term

+ References

No definition available.

+ Details

Name:	mdco_BusinessCombinationContingentConsiderationPeriodOfCollaborationTerm
Namespace Prefix:	mdco_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Business Combination, Contingent Consideration, Period Preceding Closing of Purchase

+ References

No definition available.

+ Details

Name:	mdco_BusinessCombinationContingentConsiderationPeriodPrecedingClosingOfPurchase
Namespace Prefix:	mdco_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities, Option

+ References

No definition available.

+ Details

Name:	mdco_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesOption
Namespace Prefix:	mdco_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Master Transaction Agreement, Collaboration Fee

+ References

No definition available.

+ Details

Name:	mdco_MasterTransactionAgreementCollaborationFee
Namespace Prefix:	mdco_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Master Transaction Agreement, Option Fee

+ References

No definition available.

+ Details

Name:	mdco_MasterTransactionAgreementOptionFee
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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Master Transaction Agreement, Potential Business Acquisition Period Preceding Purchase Closing Period

+ References

No definition available.

+ Details

Name:	mdco_MasterTransactionAgreementPotentialBusinessAcquisitionPeriodPrecedingPurchaseClosingPeriod
Namespace Prefix:	mdco_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Master Transaction Agreement, Potential Business Acquisition Purchase Closing Period

+ References

No definition available.

+ Details

Name:	mdco_MasterTransactionAgreementPotentialBusinessAcquisitionPurchaseClosingPeriod
Namespace Prefix:	mdco_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_BusinessAcquisitionLineItems
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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

This element represents acquisition-related costs incurred to effect a business combination which costs have been expensed during the period. Such costs include finder's fees; advisory, legal, accounting, valuation, and other professional or consulting fees; general administrative costs, including the costs of maintaining an internal acquisitions department; and may include costs of registering and issuing debt and equity securities.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 805

-SubTopic 10

-Section 25

-Paragraph 23

-URI http://asc.fasb.org/extlink&oid=34752592&loc=d3e1043-128460

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of assets acquired at the acquisition date.

+ References

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The amount of identifiable intangible assets recognized as of the acquisition date.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 805

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=39739317&loc=d3e4845-128472

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 805

-SubTopic 10

-Section 55

-Paragraph 37

-URI http://asc.fasb.org/extlink&oid=35744172&loc=d3e2207-128464

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount recognized for assets, including goodwill, in excess of (less than) the aggregate liabilities assumed.

+ References

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Details

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Period Type:	duration

- Definition

Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 20

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=35741047&loc=d3e13816-109267

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 20

-Section 45

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6388280&loc=d3e13770-109266

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Details

Name:	us-gaap_BusinessAcquisitionAxis=mdco_BristolMyersSquibbMember
Namespace Prefix:
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Period Type:

- Details

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Period Type:

Acquisitions (Recothrom) (Details) (USD $)	1 Months Ended	9 Months Ended
Acquisitions (Recothrom) (Details) (USD $)	Feb. 28, 2013 period	Sep. 30, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Assets Acquired and Liabilities Assumed
Goodwill			$ 286,532,000us-gaap_Goodwill	$ 257,694,000us-gaap_Goodwill	$ 14,671,000us-gaap_Goodwill
BMS [Member]
Business Acquisition [Line Items]
Collaboration fee	105,000,000
Option fee	10,000,000
Number of periods preceding closing of purchase	2
Period preceding closing of purchase	12 months
Period of collaboration term	24 months
Acquisition related costs		1,600,000
Assets Acquired and Liabilities Assumed
Option	62,000,000
Goodwill	21,000,000
Total Assets	115,000,000
Total purchase price	115,000,000
BMS [Member] \| Product License [Member]
Assets Acquired and Liabilities Assumed
Developed product rights	$ 32,000,000
BMS [Member]
Business Acquisition [Line Items]
Master transaction agreement purchase closing period	24 months
Master transaction agreement period preceding purchase closing period	12 months