Name:	amag_AccruedPercentageOfPromptPaymentDiscount
Namespace Prefix:	amag_
Data Type:	num:percentItemType
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Period Type:	duration

Represents the increase (decrease) in Medicaid rebate reserve during the period.

No definition available.

Name:	amag_MedicaidRebateReserveAdjustment
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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Represents the percentage of prompt payment discount given to customers as an incentive to remit payment in accordance with the stated terms of the invoice.

No definition available.

Name:	amag_PercentageOfPromptPaymentDiscount
Namespace Prefix:	amag_
Data Type:	num:percentItemType
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Period Type:	duration

Represents the period within which discount is offered to customers as an incentive to remit payment in accordance with the stated terms of the invoice.

No definition available.

Name:	amag_PeriodWithinWhichDiscountIsOfferedToCustomersForPromptPayment
Namespace Prefix:	amag_
Data Type:	xbrli:durationItemType
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Period Type:	duration

Name:	amag_SalesDiscountsGoodsAbstract
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Data Type:	xbrli:stringItemType
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Percentage of product sales allowances and accruals to total gross revenue from the sales of goods.

No definition available.

Name:	amag_SalesDiscountsReturnsAndAllowancesGoodsExpressedAsPercentageOfGrossSalesGoods
Namespace Prefix:	amag_
Data Type:	num:percentItemType
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Period Type:	duration

The aggregate selling price reductions recognized during an accounting period due to government and other rebates.

No definition available.

Name:	amag_SalesGovernmentAndOtherRebatesGoods
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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

The average period from time of product sale to payment of rebate is typically up to this period, or longer.

No definition available.

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

Name:	us-gaap_PropertyPlantAndEquipmentLineItems
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Useful life of long lived, physical assets used in the normal conduct of business and not intended for resale, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Examples include, but not limited to, land, buildings, machinery and equipment, office equipment, furniture and fixtures, and computer equipment.

No definition available.

Name:	us-gaap_PropertyPlantAndEquipmentUsefulLife
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Data Type:	xbrli:durationItemType
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Period Type:	duration

Aggregate cash discounts given by the entity for goods sold to customers including, but not limited to, early payments of accounts due. For example, selling terms of "2/10, net 30" entitle a customer to a 2% discount for prompt payment within 10 days, otherwise full payment is expected in 30 days. Discounts are a deduction from gross revenue in arriving at net revenue.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SX 210.5-03.1(a))

-URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 1

-Article 5

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Aggregate of: (i) sales discounts given by the entity, including, but not limited to, early payments of accounts due, (ii) the total deduction from sales during the period arising from goods returned by customers (other than under warranty provisions), and (iii) price reductions (allowance, price protection agreements) given by the entity. Discounts, returns and allowances are a deduction from gross revenue in arriving at net revenue.

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 1

-Article 5

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 605

-SubTopic 50

-Section 45

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6408645&loc=d3e63676-111659

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 605

-SubTopic 15

-Section 45

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6406750&loc=d3e47468-111626

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Name:	us-gaap_SalesDiscountsReturnsAndAllowancesGoodsAbstract
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Data Type:	xbrli:stringItemType
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The aggregate refunds recognized during an accounting period due to goods returned by customers (other than under warranty provisions). Returns are a deduction from gross revenue in arriving at net revenue.

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Data Type:	xbrli:monetaryItemType
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Aggregate revenue during the period from sale of goods in the normal course of business, before deducting returns, allowances and discounts.

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

Name:	us-gaap_PropertyPlantAndEquipmentByTypeAxis=amag_LaboratoryAndProductionEquipmentMember
Namespace Prefix:
Data Type:	na
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