XML 188 R52.htm IDEA: XBRL DOCUMENT
v3.25.0.1

Income Taxes (Narrative) (Details) - USD ($) $ in Thousands | 12 Months Ended
--- | ---
Dec. 31, 2023 | Dec. 31, 2022
Deferred tax assets, valuation allowance | $ 147,694 | $ 128,101
Tax credits, expiration date | Dec. 31, 2034 |
Interest or penalties | $ 0 | $ 0
Federal |  |
Operating loss carryforwards without expiration | 220,400 |
Operating Loss Carryforwards | 244,100 |
Income tax credits | 14,100 |
State |  |
Operating loss carryforwards without expiration | 400 |
Operating Loss Carryforwards | 514,900 |
Income tax credits | $ 5,200 |

X
- Definition Amount of operating loss carryforward, before tax effects, available to reduce future taxable income under enacted tax laws. + References No definition available. + Details
Name: | mbio_OperatingLossCarryforwardsWithoutExpiration
Namespace Prefix: | mbio_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of deferred tax assets for which it is more likely than not that a tax benefit will not be realized. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 740 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482685/740-10-50-2 + Details
Name: | us-gaap_DeferredTaxAssetsValuationAllowance
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition A credit or adjustment for government or taxing authority authorized decrease in taxes owed as a result of meeting certain tax policy conditions. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 230 -SubTopic 10 -Name Accounting Standards Codification -Section 45 -Paragraph 28 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482740/230-10-45-28 + Details
Name: | us-gaap_IncomeTaxCreditsAndAdjustments
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The sum of the amounts of estimated penalties and interest recognized in the period arising from income tax examinations. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 740 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 15 -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482685/740-10-50-15 + Details
Name: | us-gaap_IncomeTaxExaminationPenaltiesAndInterestExpense
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of operating loss carryforward, before tax effects, available to reduce future taxable income under enacted tax laws. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 740 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482685/740-10-50-3 + Details
Name: | us-gaap_OperatingLossCarryforwards
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Expiration date of the tax credit carryforward, in YYYY-MM-DD format. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 740 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482685/740-10-50-3 + Details
Name: | us-gaap_TaxCreditCarryforwardExpirationDate
Namespace Prefix: | us-gaap_
Data Type: | xbrli:dateItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_IncomeTaxAuthorityAxis=us-gaap_DomesticCountryMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_IncomeTaxAuthorityAxis=us-gaap_StateAndLocalJurisdictionMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |