The amount of current accrued income including current contract assets. [Refer: Accrued income including contract assets]

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Note Expiry date 2027-01-01
-Name IAS
-Number 1
-IssueDate 2025-01-01
-Paragraph 55
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2025-en-b&anchor=para_55&doctype=Standard
-URIDate 2025-03-27

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Note Expiry date 2027-01-01
-Name IAS
-Number 1
-IssueDate 2025-01-01
-Paragraph 78
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2025-en-b&anchor=para_78&doctype=Standard
-URIDate 2025-03-27

+ Details

Name:	ifrs-full_CurrentAccruedIncomeIncludingCurrentContractAssets
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The amount recognised as a current asset for expenditures made prior to the period when the economic benefit will be realised.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Note Expiry date 2027-01-01
-Name IAS
-Number 1
-IssueDate 2025-01-01
-Paragraph 112
-Subparagraph c
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2025-en-b&anchor=para_112_c&doctype=Standard
-URIDate 2025-03-27

+ Details

Name:	ifrs-full_CurrentPrepaidExpenses
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The current amount of current tax assets. [Refer: Current tax assets]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Note Expiry date 2027-01-01
-Name IAS
-Number 1
-IssueDate 2025-01-01
-Paragraph 54
-Subparagraph n
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2025-en-b&anchor=para_54_n&doctype=Standard
-URIDate 2025-03-27

+ Details

Name:	ifrs-full_CurrentTaxAssetsCurrent
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The amount of cash and cash equivalents whose use or withdrawal is restricted. [Refer: Cash and cash equivalents]

+ References

+ Details

Name:	ifrs-full_RestrictedCashAndCashEquivalents
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The amount of short-term deposits held by the entity that are not classified as cash equivalents. [Refer: Cash equivalents]

+ References

+ Details

Name:	ifrs-full_ShorttermDepositsNotClassifiedAsCashEquivalents
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of cash under liquidity agreement, classified as current.

+ References

No definition available.

+ Details

Name:	iva_CashUnderLiquidityAgreementCurrent
Namespace Prefix:	iva_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

CIR receivable relating to current period.

+ References

No definition available.

+ Details

Name:	iva_CirReceivableRelatingToCurrentPeriod
Namespace Prefix:	iva_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The amount of CIR receivable relating to prior period.

+ References

No definition available.

+ Details

Name:	iva_CirReceivableRelatingToPriorPeriods
Namespace Prefix:	iva_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Closure of short-term deposit account.

+ References

No definition available.

+ Details

Name:	iva_ClosureOfShortTermDepositAccount
Namespace Prefix:	iva_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The increase (decrease) during the reporting period in the amount of outstanding money paid in advance for goods or services that bring economic benefits for future periods.

+ References

No definition available.

+ Details

Name:	iva_IfrsIncreaseDecreaseInPrepaidExpense
Namespace Prefix:	iva_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of increase (decrease) in short-term deposit accounts.

+ References

No definition available.

+ Details

Name:	iva_IncreaseDecreaseInShortTermDepositAccounts
Namespace Prefix:	iva_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Opening of short-term deposit account.

+ References

No definition available.

+ Details

Name:	iva_OpeningOfShortTermDepositAccount
Namespace Prefix:	iva_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes of the table.

+ References

No definition available.

+ Details

Name:	iva_TradeReceivablesAndOtherCurrentAssetsAndReceivablesLineItems
Namespace Prefix:	iva_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	ifrs-full_CounterpartiesAxis=iva_SocieteGeneraleMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_CounterpartiesAxis=iva_CreditAgricoleBankMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_CurrencyAxis=currency_EUR
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_CurrencyAxis=currency_USD
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	iva_IfrsSaleOfStockAxis=iva_AtMarketOfferingMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Notes to the unaudited interim condensed consolidated statement of financial position - Other (Details) € in Thousands, $ in Millions	6 Months Ended
	Jun. 30, 2026 EUR (€)	Jun. 30, 2026 USD ($)	Dec. 31, 2025 EUR (€)	Dec. 31, 2025 USD ($)
Trade receivables, tax receivables and other current assets
Tax receivables	€ 3,083		€ 2,281
CIR receivable relating to prior period	2,300
CIR receivable relating to current period	800			$ 2.3
Increase (decrease) in prepaid expenses	(2,300)
Minimum cash covenant under Debt Financing Transaction	30,000
Increase in short-term deposit accounts	(63,800)
Prepaid expenses	1,660		3,952
Short-term deposit accounts	67,765		131,558
Current accrued income	862		1,575
Liquidity agreement - Cash	0		527
Societe Generale
Trade receivables, tax receivables and other current assets
Closure of short-term deposit account	63,100	$ 71.8
Opening of short-term deposit account	34,700	39.5
Crdit Agricole bank
Trade receivables, tax receivables and other current assets
Closure of short-term deposit account	49,600	56.5
Opening of short-term deposit account	14,400	$ 16.4
Euro Member Countries, Euro \| Societe Generale
Trade receivables, tax receivables and other current assets
Short-term deposit accounts			53,000
Euro Member Countries, Euro \| Crdit Agricole bank
Trade receivables, tax receivables and other current assets
Short-term deposit accounts			43,000
United States of America, Dollars \| Societe Generale
Trade receivables, tax receivables and other current assets
Short-term deposit accounts			22,500	26.5
United States of America, Dollars \| Crdit Agricole bank
Trade receivables, tax receivables and other current assets
Short-term deposit accounts			12,400	$ 14.6
ATM
Trade receivables, tax receivables and other current assets
Prepaid expenses	€ 400		€ 1,300