Commitments and Contingencies (Details)	3 Months Ended
Mar. 31, 2015
Minimum
Patent appeals and market exclusivity
Ferumoxytol term of data and market exclusivity even if there is no successful outcome from the appeals process	8 years
Maximum
Patent appeals and market exclusivity
Ferumoxytol term of data and market exclusivity even if there is no successful outcome from the appeals process	10 years

Represents the term of data and market exclusivity even without a successful outcome from the appeals process.

No definition available.

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