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

Lessee, Operating Lease, Option To Extend, Number

+ References

No definition available.

+ Details

Name:	amag_LesseeOperatingLeaseOptionToExtendNumber
Namespace Prefix:	amag_
Data Type:	xbrli:integerItemType
Balance Type:	na
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

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)(3)
-URI http://asc.fasb.org/extlink&oid=35744584&loc=d3e6927-128479

+ Details

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

- Definition

Term of lessee's operating lease renewal, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 50
-Paragraph 3
-Subparagraph (a)(3)
-URI http://asc.fasb.org/extlink&oid=77888426&loc=SL77918673-209980

+ Details

Name:	us-gaap_LesseeLeasingArrangementsOperatingLeasesRenewalTerm
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Term of lessee's operating lease, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

+ References

+ Details

Name:	us-gaap_LesseeLeasingArrangementsOperatingLeasesTermOfContract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- 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

Rental expense for the reporting period incurred under operating leases, including minimum and any contingent rent expense, net of related sublease income.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 840
-SubTopic 20
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=77902758&loc=d3e41499-112717

+ Details

Name:	us-gaap_OperatingLeasesRentExpenseNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
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

- Definition

Amount of cash restricted as to withdrawal or usage, classified as noncurrent. Cash includes, but is not limited to, currency on hand, demand deposits with banks or financial institutions, and other accounts with general characteristics of demand deposits.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 50
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=98513485&loc=SL98516268-108586

Reference 2: 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(17))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section 45
-Paragraph 4
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=82887183&loc=d3e6812-107765

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3044-108585

+ Details

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

- 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:

- Details

Name:	us-gaap_CounterpartyNameAxis=amag_EndoceuticsInc.Member
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_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsAxis=us-gaap_LetterOfCreditMember
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_ProductOrServiceAxis=amag_BremelanotideProductsMember
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_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:

Commitments and Contingencies - Narrative (Details) $ in Thousands		1 Months Ended			12 Months Ended
	Apr. 03, 2017 USD ($)	Feb. 28, 2017 USD ($)	Jul. 31, 2015 USD ($)	Sep. 30, 2013 extension_term	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Nov. 30, 2014 USD ($)
Legal Proceedings
Term of contract					5 years 2 months
Option to extend, number \| extension_term				1
Extension term				5 years
Security deposit					$ 656	$ 2,593
Operating leases, rent expense, net					3,000	2,800	$ 1,500
Remaining minimum purchase commitments					16,500
Payments					39,793	92,130	456
Lumara Health Inc.
Legal Proceedings
Additional merger consideration								$ 350,000
First Milestone \| Lumara Health Inc.
Legal Proceedings
Payments					50,000	100,000
Endoceutics, Inc.
Legal Proceedings
Future contingent payments (up to)					9,300	0	$ 0
Velo Bio, LLC \| Option Exercise and Regulatory Milestone Achievement
Legal Proceedings
Future contingent payments (up to)			$ 65,000
Velo Bio, LLC \| Annual Sales Milestone Achievements
Legal Proceedings
Future contingent payments (up to)			250,000
Velo Bio, LLC \| Annual Sales Milestone Achievements \| Minimum
Legal Proceedings
Sales milestone targets			100,000
Velo Bio, LLC \| Annual Sales Milestone Achievements \| Maximum
Legal Proceedings
Sales milestone targets			$ 900,000
Letter of Credit
Legal Proceedings
Security deposit					700	$ 600
Intrarosa \| Endoceutics, Inc. \| Delivery of Intrarosa Launch Quantities
Legal Proceedings
Future contingent payments (up to)					10,000
Intrarosa \| Endoceutics, Inc. \| First Sales Milestone Achievement
Legal Proceedings
Future contingent payments (up to)	$ 15,000				15,000
Potential milestone payment, triggering event, sales	150,000				150,000
Intrarosa \| Endoceutics, Inc. \| Second Sales Milestone Achievement
Legal Proceedings
Future contingent payments (up to)	30,000				30,000
Potential milestone payment, triggering event, sales	300,000				300,000
Intrarosa \| Endoceutics, Inc. \| Third Sales Milestone Achievement
Legal Proceedings
Future contingent payments (up to)	850,000				850,000
Potential milestone payment, triggering event, sales	500,000				500,000
Intrarosa \| Endoceutics, Inc. \| Tiered Royalties
Legal Proceedings
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
Bremelanotide Products \| Palatin Technologies, Inc. \| First Sales Milestone Achievement
Legal Proceedings
Future contingent payments (up to)		$ 25,000
Potential milestone payment, triggering event, sales		$ 250,000
Bremelanotide Products \| Palatin Technologies, Inc. \| Tiered Royalties
Legal Proceedings
Period after first commercial sale		10 years
Bremelanotide Products \| Palatin Technologies, Inc. \| Regulatory and Commercial Milestone Payments
Legal Proceedings
Future contingent payments (up to)					$ 380,000
Bremelanotide Products \| Palatin Technologies, Inc. \| Regulatory Milestone Achievement
Legal Proceedings
Future contingent payments (up to)		$ 80,000			80,000
Bremelanotide Products \| Palatin Technologies, Inc. \| Regulatory Milestone Achievement, Acceptance by U.S.Food And Drug Administration of New Drug Application
Legal Proceedings
Future contingent payments (up to)		20,000			20,000
Bremelanotide Products \| Palatin Technologies, Inc. \| Regulatory Milestone Achievement, U.S.Food and Drug Administration Approval
Legal Proceedings
Future contingent payments (up to)		60,000			60,000
Bremelanotide Products \| Palatin Technologies, Inc. \| Achievement of Certain Annual Sales Milestones Over Course of License Agreement
Legal Proceedings
Future contingent payments (up to)		$ 300,000			$ 300,000