Represents the number of equity-based compensation plans.

No definition available.

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- Definition

Represents the maximum percentage of an employee's compensation that can be deducted and used to purchase shares under an Employee Stock Purchase Plan.

+ References

No definition available.

+ Details

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- Definition

Period which an employee's right to exercise an award is no longer contingent on satisfaction of either a service condition, market condition or a performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the 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 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

+ Details

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- 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

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- Definition

The maximum number of shares (or other type of equity) originally approved (usually by shareholders and board of directors), net of any subsequent amendments and adjustments, for awards under the equity-based compensation plan. As stock or unit options and equity instruments other than options are awarded to participants, the shares or units remain authorized and become reserved for issuance under outstanding awards (not necessarily vested).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)(3)
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

+ Details

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Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

Period from grant date that an equity-based award expires, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the 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 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)(2)
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

+ Details

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Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Purchase price of common stock expressed as a percentage of its fair value.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of shares issued during the period as a result of an employee stock purchase plan.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21463-112644

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(29))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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-Paragraph 1
-Subparagraph (SX 210.3-04)
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+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Details

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Namespace Prefix:
Data Type:	na
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Period Type:

- Details

Name:	us-gaap_AwardTypeAxis=amag_EmployeeAndNonEmployeeStockOptionMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

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

- Details

Name:	us-gaap_PlanNameAxis=amag_StockPlan2000Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_PlanNameAxis=amag_LumaraHealth2013PlanMember
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Data Type:	na
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Period Type:

- Details

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Data Type:	na
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Period Type:

- Details

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- Details

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Equity-Based Compensation - Plan Information (Details)	1 Months Ended	9 Months Ended	17 Months Ended
Equity-Based Compensation - Plan Information (Details)	May 31, 2015 shares	Sep. 30, 2016 plan shares	Sep. 30, 2016 shares	Nov. 30, 2014 shares
Equity compensation plans
Number of equity compensation plans \| plan		4
2007 Plan
Equity compensation plans
Shares authorized for issuance		6,995,325	6,995,325
Remaining number of shares available for future grants		1,722,478	1,722,478
2007 Plan \| Stock Options \| Minimum
Equity compensation plans
Offering period term		7 years
2007 Plan \| Stock Options \| Maximum
Equity compensation plans
Offering period term		10 years
2000 Plan \| Stock Options
Equity compensation plans
Offering period term		10 years
Lumara Health 2013 Plan
Equity compensation plans
Shares authorized for issuance				200,000
Remaining number of shares available for future grants		40,356	40,356
Lumara Health 2013 Plan \| Stock Options
Equity compensation plans
Offering period term		10 years
2015 ESPP
Equity compensation plans
Shares authorized for issuance	200,000
Offering period term		6 months
Annual maximum percentage of employee compensation available for ESPP share purchases (as a percent)	10.00%
Purchase price per share as a percentage of fair market value of common stock on the first or last day of the plan period	85.00%
Shares issued			41,679
Inducement Grants \| Stock Options
Equity compensation plans
Award vesting period		4 years
Inducement Grants \| Restricted Stock Units
Equity compensation plans
Award vesting period		3 years