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Subsequent Event (Details) (USD $)
Share data in Millions, unless otherwise specified
1 Months Ended 3 Months Ended 0 Months Ended
Apr. 30, 2015
May 31, 2014
Mar. 31, 2015
Apr. 20, 2015
Apr. 16, 2015
Apr. 21, 2015
Apr. 30, 2015
Subsequent Event              
Commission percentage required to pay   2.00%mnta_CommissionPercentageOfGrossProceedsFromSaleOfCommonStock          
Net proceeds from issuance of common stock under ATM facility $ 75,000,000us-gaap_ProceedsFromIssuanceOfCommonStock   $ 33,665,000us-gaap_ProceedsFromIssuanceOfCommonStock $ 21,500,000us-gaap_ProceedsFromIssuanceOfCommonStock      
Sale of shares of common stock through the ATM 1.4mnta_StockSoldDuringPeriodSharesNewIssues   4.1mnta_StockSoldDuringPeriodSharesNewIssues        
Second Sandoz Collaboration Agreement              
Subsequent Event              
Regulatory milestone payment earned         10,000,000mnta_CollaborativeArrangementUnitedStatesBasedMilestonePaymentsRecognized
/ us-gaap_TypeOfArrangementAxis
= mnta_SandozCollaboration2006Member
   
Subsequent event              
Subsequent Event              
Aggregate value of common stock issued pursuant to the sales agreement           75,000,000us-gaap_StockIssuedDuringPeriodValueNewIssues
/ us-gaap_SubsequentEventTypeAxis
= us-gaap_SubsequentEventMember
 
Commission percentage required to pay           2.00%mnta_CommissionPercentageOfGrossProceedsFromSaleOfCommonStock
/ us-gaap_SubsequentEventTypeAxis
= us-gaap_SubsequentEventMember
 
Net proceeds from issuance of common stock under ATM facility             6,900,000us-gaap_ProceedsFromIssuanceOfCommonStock
/ us-gaap_SubsequentEventTypeAxis
= us-gaap_SubsequentEventMember
Sale of shares of common stock through the ATM             0.4mnta_StockSoldDuringPeriodSharesNewIssues
/ us-gaap_SubsequentEventTypeAxis
= us-gaap_SubsequentEventMember
Subsequent event | Second Sandoz Collaboration Agreement              
Subsequent Event              
Regulatory milestone payment earned         $ 10,000,000mnta_CollaborativeArrangementUnitedStatesBasedMilestonePaymentsRecognized
/ us-gaap_SubsequentEventTypeAxis
= us-gaap_SubsequentEventMember
/ us-gaap_TypeOfArrangementAxis
= mnta_SandozCollaboration2006Member