XML 42 R32.htm IDEA: XBRL DOCUMENT
v3.23.3

Clinical Trial and Sponsored Research Agreements (Other - Sponsored Research and Clinical Trial Agreements) (Narrative) (Details) - USD ($) $ in Thousands |  |  | 1 Months Ended | 3 Months Ended | 9 Months Ended
--- | --- | --- | --- | --- | ---
Sep. 08, 2021 | Jul. 03, 2017 | Oct. 31, 2022 | Jan. 31, 2022 | Jun. 30, 2021 | Nov. 30, 2020 | Sep. 30, 2023 | Sep. 30, 2022 | Sep. 30, 2023 | Sep. 30, 2022
License, Clinical Trial and Sponsored Research Agreements |  |  |  |  |  |  |  |  |  |
Research and development expense |  |  |  |  |  |  | $ 9,477 | $ 15,419 | $ 34,313 | $ 46,872
Sponsored Research and Clinical Trial Agreements [Member] |  |  |  |  |  |  |  |  |  |
License, Clinical Trial and Sponsored Research Agreements |  |  |  |  |  |  |  |  |  |
Research and development expense |  |  |  |  |  |  | 364 | 1,836 | 3,739 | 4,884
Fred Hutchinson Cancer Center [Member] | CD20 (MB-106) [Member] |  |  |  |  |  |  |  |  |  |
License, Clinical Trial and Sponsored Research Agreements |  |  |  |  |  |  |  |  |  |
Total reimbursement payments made |  |  |  |  |  |  | 8,400 |  | 8,400 |
Fred Hutchinson Cancer Center [Member] | Sponsored Research and Clinical Trial Agreements [Member] | CD20 (MB-106) [Member] |  |  |  |  |  |  |  |  |  |
License, Clinical Trial and Sponsored Research Agreements |  |  |  |  |  |  |  |  |  |
Milestones payable |  | $ 5,300 |  |  |  |  |  |  |  |
Additional milestone payments |  |  |  | $ 2,200 |  | $ 1,800 |  |  |  |
Research and development expense |  |  |  |  |  |  | 142 | 132 | 1,239 | 978
St. Jude Children's Research Hospital [Member] | ST. Jude - XSCID [Member] |  |  |  |  |  |  |  |  |  |
License, Clinical Trial and Sponsored Research Agreements |  |  |  |  |  |  |  |  |  |
Total reimbursement payments made |  |  |  |  |  |  | 3,500 |  | 3,500 |
Mayo Clinic [Member] |  |  |  |  |  |  |  |  |  |
License, Clinical Trial and Sponsored Research Agreements |  |  |  |  |  |  |  |  |  |
Total reimbursement payments made |  |  |  |  |  |  | 2,200 |  | 2,200 |
Mayo Clinic [Member] | Sponsored Research and Clinical Trial Agreements [Member] |  |  |  |  |  |  |  |  |  |
License, Clinical Trial and Sponsored Research Agreements |  |  |  |  |  |  |  |  |  |
Research and development expense |  |  |  |  |  |  |  | 269 | 551 | 731
Mayo Clinic [Member] | Sponsored Research and Clinical Trial Agreements [Member] | Car T Technology [Member] |  |  |  |  |  |  |  |  |  |
License, Clinical Trial and Sponsored Research Agreements |  |  |  |  |  |  |  |  |  |
Milestones payable |  |  |  |  | $ 2,100 |  |  |  |  |
Agreement term |  |  |  |  | 2 years |  |  |  |  |
Mayo Clinic [Member] | Clinical Trial Agreements [Member] | Car T Technology [Member] |  |  |  |  |  |  |  |  |  |
License, Clinical Trial and Sponsored Research Agreements |  |  |  |  |  |  |  |  |  |
Milestones payable |  |  | $ 100 |  |  |  |  |  |  |
Leiden University Medical Centre [Member] | Sponsored Research and Clinical Trial Agreements [Member] | RAG1 SCID (MB-110) [Member] |  |  |  |  |  |  |  |  |  |
License, Clinical Trial and Sponsored Research Agreements |  |  |  |  |  |  |  |  |  |
Research and development expense |  |  |  |  |  |  | $ 125 | $ 92 | $ 349 | $ 357
Agreement term | 5 years |  |  |  |  |  |  |  |  |

X
- Definition The amount of additional milestones payable under the arrangement. + References No definition available. + Details
Name: | mbio_AdditionalMilestonesPayableUnderArrangement
Namespace Prefix: | mbio_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The amount of milestones payable under the arrangement. + References No definition available. + Details
Name: | mbio_MilestonesPayableUnderArrangement
Namespace Prefix: | mbio_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Represents total payments for reimbursable expenses over the lifetime of the agreement. + References No definition available. + Details
Name: | mbio_ReimbursementOfFeesTotalPayments
Namespace Prefix: | mbio_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition The term of the research arrangement. + References No definition available. + Details
Name: | mbio_ResearchArrangementTerm
Namespace Prefix: | mbio_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

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 Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 808 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (d) -Publisher FASB -URI https://asc.fasb.org//1943274/2147479402/808-10-50-1 + Details
Name: | us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The costs incurred in a planned search or critical investigation aimed at discovery of new knowledge with the hope that such knowledge will be useful in developing a new product or service, a new process or technique, or in bringing about a significant improvement to an existing product or process; or to translate research findings or other knowledge into a plan or design for a new product or process or for a significant improvement to an existing product or process whether intended for sale or the entity's use, during the reporting period charged to research and development projects, excluding in-process research and development acquired in a business combination consummated during the period. Excludes software research and development, which has a separate concept. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 730 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org//1943274/2147482916/730-10-50-1 + Details
Name: | us-gaap_ResearchAndDevelopmentExpenseExcludingAcquiredInProcessCost
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Details
Name: | us-gaap_TypeOfArrangementAxis=mbio_SponsoredResearchAndClinicalTrialAgreementsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_CounterpartyNameAxis=mbio_FredHutchinsonCancerResearchCenterMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_ProductOrServiceAxis=mbio_Cd20TechnologyProductOrProcessMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_CounterpartyNameAxis=mbio_St.JudeChildrensResearchHospitalMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_ProductOrServiceAxis=mbio_StJudeXscidMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_CounterpartyNameAxis=mbio_MayoClinicMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_ProductOrServiceAxis=mbio_CarTTechnologyProductOrProcessMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_TypeOfArrangementAxis=mbio_ClinicalTrialAgreementsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_CounterpartyNameAxis=mbio_LeidenUniversityMedicalCentreMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_ProductOrServiceAxis=mbio_Rag1ScidMb110Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |