- Definition

Collaborative Arrangement, Amount Of Cost Of Goods To Be Deducted From Share Of Defined Profits Due To Milestone Not Being Met

+ References

No definition available.

+ Details

Name:	mnta_CollaborativeArrangementAmountOfCostOfGoodsToBeDeductedFromShareOfDefinedProfitsDueToMilestoneNotBeingMet
Namespace Prefix:	mnta_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Collaborative Arrangement, Milestone Payments, No Longer Eligible To Earn, Commercial Milestone

+ References

No definition available.

+ Details

Name:	mnta_CollaborativeArrangementMilestonePaymentsNoLongerEligibleToEarnCommercialMilestone
Namespace Prefix:	mnta_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The amount of milestone payments which the entity may receive for the entire length of the applicable agreement.

+ References

No definition available.

+ Details

Name:	mnta_CollaborativeArrangementMilestonePaymentsPossible
Namespace Prefix:	mnta_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Represents the percentage of net profit shared on sales of the product if no third-party competitors are marketing an interchangeable generic version of Product and Equivalent Product.

+ References

No definition available.

+ Details

Name:	mnta_CollaborativeArrangementPercentageOfProfitSharing
Namespace Prefix:	mnta_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the percentage of royalty to be paid by Sandoz of contractually defined profits on net sales.

+ References

No definition available.

+ Details

Name:	mnta_CollaborativeArrangementPercentageOfRoyaltyOnContractuallyDefinedProfitsOnSales
Namespace Prefix:	mnta_
Data Type:	num:percentItemType
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_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_TypeOfArrangementAxis=mnta_SandozCollaboration2006Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=mnta_NovartisPharmaAGMember
Namespace Prefix:
Data Type:	na
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- Details

Name:	srt_RangeAxis=srt_MaximumMember
Namespace Prefix:
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Collaboration and License Agreements - 2006 Sandoz Collaboration Agreement (Details) - 2006 Sandoz Collaboration Agreement - USD ($)		12 Months Ended
	Jun. 18, 2015	Dec. 31, 2018	Oct. 31, 2017	Oct. 04, 2017
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Percentage of royalty based on contractually defined profits on sales	50.00%	50.00%
Milestone payments, no longer eligible to earn, commercial milestone			$ 80,000,000
Amount of cost of goods to be deducted from share of defined profits due to milestone not being met				$ 9,800,000
Novartis Pharma AG
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Percentage of contractual profits earned under collaborative arrangement		50.00%
Maximum
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Milestone payments possible per agreement			$ 30,000,000