Name:	mrns_CollaborationAgreementPaymentReceivableUponAchievementOfSpecificClinicalAndCommercialAchievements
Namespace Prefix:	mrns_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

The amount of reimbursement of research and development cost receivable as at the end of the reporting period.

No definition available.

Name:	mrns_CollaborationAgreementReimbursementOfResearchAndDevelopmentCostReceivable
Namespace Prefix:	mrns_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Term of collaboration agreement.

No definition available.

Name:	mrns_CollaborationAgreementTerm
Namespace Prefix:	mrns_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

The percentage of the upfront fee which must be refunded in the event of termination of the collaboration agreement.

No definition available.

Name:	mrns_CollaborationAgreementTerminationPercentageOfUpfrontFee
Namespace Prefix:	mrns_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

The upfront fee received per the collaboration agreement.

No definition available.

Name:	mrns_CollaborationAgreementUpfrontFee
Namespace Prefix:	mrns_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Represents the number of days from receipt of the final report of the study, in which the collaboration agreement may be terminated.

No definition available.

Name:	mrns_RightToTerminateCollaborationAgreementNumberOfDaysAfterReceiptOfFinalReport
Namespace Prefix:	mrns_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

Amount of liability for consideration received or receivable from customer which is not included in transaction price, when consideration is expected to be refunded to customer, classified as current.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 55
-Paragraph 27
-URI http://asc.fasb.org/extlink&oid=121551570&loc=SL49130611-203046-203046

Name:	us-gaap_ContractWithCustomerRefundLiabilityCurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

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.

No definition available.