Asset Acquisition, Contingent Consideration, Liability

No definition available.

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

- Definition

Asset Acquisition, Contingent Consideration Terms, Net Sales Threshold For Commercial Product Life

+ References

No definition available.

+ Details

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

- Definition

Asset Acquisition, Contingent Consideration Terms, Royalty Percentage

+ References

No definition available.

+ Details

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

- Definition

Asset Acquisition, Contingent Consideration Terms, Threshold Period After Initial Sale

+ References

No definition available.

+ Details

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

- Definition

Asset Acquisition, Potential Milestone Payment, Triggering Event, Threshold Amount

+ References

No definition available.

+ Details

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

- Definition

Option Agreement, Contingent Consideration, Liability

+ References

No definition available.

+ Details

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

- Definition

Option Agreement, Potential Sales Milestone Payment, Triggering Event, Threshold Amount

+ References

No definition available.

+ Details

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

- Definition

For contingent consideration arrangements recognized in connection with a business combination, this element represents an estimate of the high-end of the potential range (undiscounted) of the consideration which may be paid.

+ References

+ Details

Name:	us-gaap_BusinessCombinationContingentConsiderationArrangementsRangeOfOutcomesValueHigh
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of liability recognized arising from contingent consideration in a business combination.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 50
-Paragraph 1
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=35744584&loc=d3e6927-128479

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 35
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=6911338&loc=d3e6819-128478

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 25
-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=6911189&loc=d3e6408-128476

+ Details

Name:	us-gaap_BusinessCombinationContingentConsiderationLiability
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

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.

+ References

No definition available.

+ Details

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

- Definition

Amount of cash outflow, not made soon after acquisition date of business combination, to settle contingent consideration liability up to amount recognized at acquisition date, including, but not limited to, measurement period adjustment and less amount paid soon after acquisition date.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 15
-Subparagraph (f)
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3291-108585

+ Details

Name:	us-gaap_PaymentForContingentConsiderationLiabilityFinancingActivities
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Minimum amount to be expended to satisfy the terms of arrangements in which the entity has agreed to expend funds to procure goods or services, excluding long-term purchase commitments or unconditional purchase obligations.

+ References

Reference 1: 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(a)(19))
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Reference 2: 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(17))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 3: 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(25))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_PurchaseCommitmentRemainingMinimumAmountCommitted
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

Name:	us-gaap_CounterpartyNameAxis=amag_EndoceuticsInc.Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ProductOrServiceAxis=amag_IntrarosaMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

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

- Details

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

- Details

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

- Details

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

- Details

Name:	us-gaap_CounterpartyNameAxis=amag_PalatinTechnologiesInc.Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ProductOrServiceAxis=amag_BremelanotideProductsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

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

- Details

Name:	us-gaap_ContingentConsiderationByTypeAxis=amag_RegulatoryMilestoneAchievementAcceptanceByU.S.FoodAndDrugAdministrationOfNewDrugApplicationMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ContingentConsiderationByTypeAxis=amag_RegulatoryMilestoneAchievementU.S.FoodAndDrugAdministrationApprovalMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

Name:	us-gaap_CounterpartyNameAxis=amag_VeloBioLLCMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

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

- Details

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

- Details

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

- Details

Name:	us-gaap_BusinessAcquisitionAxis=amag_LumaraHealthInc.Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

Commitments and Contingencies (Details) - USD ($) $ in Thousands		1 Months Ended	3 Months Ended
	Apr. 03, 2017	Jul. 31, 2015	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017	Nov. 30, 2014
Commitments
Minimum purchase commitments			$ 29,900
Contingent consideration paid			44	$ 83
Asset acquisition, contingent consideration liability			20,000		$ 0
Endoceutics, Inc. \| Intrarosa \| Delivery Of Intrarosa Launch Quantities
Commitments
Asset acquisition, contingent consideration liability			10,000
Endoceutics, Inc. \| Intrarosa \| First Sales Milestone Achievement
Commitments
Asset acquisition, contingent consideration liability	$ 15,000		15,000
Potential milestone payment, triggering event, sales	150,000		150,000
Endoceutics, Inc. \| Intrarosa \| Second Sales Milestone Achievement
Commitments
Asset acquisition, contingent consideration liability	30,000		30,000
Potential milestone payment, triggering event, sales	300,000		300,000
Endoceutics, Inc. \| Intrarosa \| Third Sales Milestone Achievement
Commitments
Asset acquisition, contingent consideration liability	850,000		850,000
Potential milestone payment, triggering event, sales	500,000		500,000
Endoceutics, Inc. \| Intrarosa \| Tiered Royalties
Commitments
Potential milestone payment, triggering event, sales	$ 150,000		$ 150,000
Royalty percentage, maximum	20.00%		20.00%
Net sales threshold, future contingent payments	$ 1,000,000		$ 1,000,000
Period after first commercial sale	10 years		10 years
Palatin Technologies, Inc. \| Bremelanotide Products \| First Sales Milestone Achievement
Commitments
Asset acquisition, contingent consideration liability			$ 25,000
Potential milestone payment, triggering event, sales			$ 250,000
Palatin Technologies, Inc. \| Bremelanotide Products \| Tiered Royalties
Commitments
Period after first commercial sale			10 years
Palatin Technologies, Inc. \| Bremelanotide Products \| Regulatory And Commercial Milestone Payments
Commitments
Asset acquisition, contingent consideration liability			$ 380,000
Palatin Technologies, Inc. \| Bremelanotide Products \| Regulatory Milestone Achievement
Commitments
Asset acquisition, contingent consideration liability			80,000
Palatin Technologies, Inc. \| Bremelanotide Products \| Regulatory Milestone Achievement, Acceptance By U.S.Food And Drug Administration Of New Drug Application
Commitments
Asset acquisition, contingent consideration liability			20,000
Palatin Technologies, Inc. \| Bremelanotide Products \| Regulatory Milestone Achievement, U.S.Food And Drug Administration Approval
Commitments
Asset acquisition, contingent consideration liability			60,000
Palatin Technologies, Inc. \| Bremelanotide Products \| Achievement of Certain Annual Sales Milestones over Course of License Agreement
Commitments
Asset acquisition, contingent consideration liability			300,000
Velo Bio, LLC \| Option Exercise and Regulatory Milestone Achievement
Commitments
Future contingent payments (up to)		$ 65,000
Velo Bio, LLC \| Annual Sales Milestone Achievements
Commitments
Future contingent payments (up to)		250,000
Minimum \| Velo Bio, LLC \| Annual Sales Milestone Achievements
Commitments
Sales milestone targets		100,000
Maximum \| Velo Bio, LLC \| Annual Sales Milestone Achievements
Commitments
Sales milestone targets		$ 900,000
Lumara Health Inc.
Commitments
Contingent consideration (up to)			200,000			$ 350,000
Business acquisition, contingent consideration, liability			50,000
Lumara Health Inc. \| Annual Net Sales Milestone
Commitments
Contingent consideration paid			$ 150,000