Name:	amag_PaymentForExerciseOfOptionToAcquireGlobalRightsToDigoxinImmuneFabProgram
Namespace Prefix:	amag_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Possible Increase in Milestone Payment Amount, Percentage

No definition available.

Name:	amag_PossibleIncreaseinMilestonePaymentAmountPercentage
Namespace Prefix:	amag_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

Research And Development Asset Acquired Other Than Through Business Combination, Expiration Period

No definition available.

Name:	amag_ResearchAndDevelopmentAssetAcquiredOtherThanThroughBusinessCombinationExpirationPeriod
Namespace Prefix:	amag_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

Research and Development Asset Acquired Other Than Through Business Combination, Future Contingent Payments

No definition available.

Name:	amag_ResearchAndDevelopmentAssetAcquiredOtherThanThroughBusinessCombinationFutureContingentPayments
Namespace Prefix:	amag_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Research and Development Asset Acquired Other than Through Business Combination, Aggregate Research Reimbursement Expense

No definition available.

Name:	amag_ResearchAndDevelopmentAssetAcquiredOtherthanThroughBusinessCombinationAggregateResearchReimbursementExpense
Namespace Prefix:	amag_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Research and Development Asset Acquired Other Than Through Business Combination, Sales Milestone

No definition available.

Name:	amag_ResearchandDevelopmentAssetAcquiredOtherThanThroughBusinessCombinationSalesMilestone
Namespace Prefix:	amag_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Research and Development Asset Acquired Other Than Through Business Combination, Sales Milestone Threshold

No definition available.

Name:	amag_ResearchandDevelopmentAssetAcquiredOtherThanThroughBusinessCombinationSalesMilestoneThreshold
Namespace Prefix:	amag_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Represents the payments due for sales milestones based upon the achievement of annual sales milestones.

No definition available.

Name:	amag_SalesMilestonePaymentsBasedOnAchievementOfAnnualSalesMilestones
Namespace Prefix:	amag_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Represents the annual sales milestone targets that will require additional payments.

No definition available.

Name:	amag_SalesMilestoneTargets
Namespace Prefix:	amag_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Upfront payment made for the option to acquire the global rights to the DIF program.

No definition available.

Name:	amag_UpfrontPaymentIssuedForOptionAgreement
Namespace Prefix:	amag_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

Name:	us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

The amount of costs incurred under a research and development arrangement accounted for as a contract to perform research and development for others.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 730
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=6420387&loc=d3e23199-108380

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 730
-SubTopic 20
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=6420387&loc=d3e23221-108380

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

Name:	us-gaap_TypeOfArrangementAxis=amag_OptionAgreementWithVeloBioToAcquireRightsToDifMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_RangeAxis=us-gaap_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_RangeAxis=us-gaap_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_CapitalizedCostsOfUnprovedPropertiesExcludedFromAmortizationByPropertyOrProjectAxis=amag_PalatinLicenseAgreementMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_ResearchAndDevelopmentArrangementContractToPerformForOthersByTypeAxis=us-gaap_LicenseAgreementTermsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_ContingentConsiderationByTypeAxis=amag_ContingentConsiderationRegulatoryMilestoneAchievementMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: