Percentage of employee contributions may be deferred to a defined contribution plan.

No definition available.

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Namespace Prefix:	mtva_
Data Type:	dtr-types:percentItemType
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Period Type:	duration

- Definition

Employee eligibility age criteria under defined contribution plan.

+ References

No definition available.

+ Details

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Data Type:	xbrli:durationItemType
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Period Type:	duration

- Definition

Period which the employer contribution will be vested under defined contribution plan, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

Name:	mtva_DefinedContributionPlanEmployerMatchingContributionVestingPercentage
Namespace Prefix:	mtva_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage of employee contribution vested on contribution made by employee.

+ References

No definition available.

+ Details

Name:	mtva_EmployeeCompensationVestingPercentageOnContribution
Namespace Prefix:	mtva_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- 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

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

- Definition

Amount of discretionary contributions made by an employer to a defined contribution plan.

+ References

No definition available.

+ Details

Name:	us-gaap_DefinedContributionPlanEmployerDiscretionaryContributionAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

Name:	srt_RangeAxis=srt_MaximumMember
Namespace Prefix:
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Balance Type:
Period Type:

Commitments and Contingencies - Employment agreements and Employee benefit plan (Details) - USD ($)	1 Months Ended	12 Months Ended
	Jan. 31, 2019	Dec. 31, 2024	Dec. 31, 2023
License Agreements
Minimum age of employee to cover under the plan	21 years
Employer matches vesting period	6 years
Percentage of employee contribution vested on their contribution	100.00%
Amount of discretionary matching contributions on employee deferrals		$ 0	$ 0
Maximum
License Agreements
Employee compensation deferred percentage	90.00%