v3.19.3.a.u2

Commitments and Contingencies - Strategic Collaborations (Details) - PCV Agreement - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018	Apr. 30, 2018	Jun. 30, 2016
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Budgeted amount				$ 250.0
PCV products
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Budgeted amount	$ 243.0	$ 243.0	$ 243.0

X

- Definition

Research And Development Arrangement, Contract To Perform For Others, Maximum Amount

+ References

No definition available.

+ Details

Name:	mrna_ResearchAndDevelopmentArrangementContractToPerformForOthersMaximumAmount
Namespace Prefix:	mrna_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

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

X

- Details

Name:	us-gaap_ResearchAndDevelopmentArrangementContractToPerformForOthersByTypeAxis=mrna_PersonalizedMRNACancerVaccinesPCVCollaborationAndLicenseAgreementWithMerckSharpAndDohmeCorpMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_CapitalizedCostsOfUnprovedPropertiesExcludedFromAmortizationByPropertyOrProjectAxis=mrna_PersonalizedMRNACancerVaccinesProductsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: