Trade receivables, tax receivables and other current assets - Other Current Assets and Receivables (Details) - EUR (€) € in Thousands	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Trade receivables, tax receivables and other current assets
CIR and other research tax credits	€ 2,267	€ 4,915	€ 5,333
Other	14	25	19
Tax receivables	2,281	4,941	5,352
Prepaid expenses	3,952	2,442	4,656
Short-term deposit accounts	131,558	0	70
Current accrued income	1,575	1,574	1,047
Liquidity agreement - Cash	527	349	422
VAT receivables	3,148	5,055	5,066
Other receivables	101	56	435
Other current assets	140,861	9,476	11,696
Other current assets and receivables	€ 143,142	€ 14,417	€ 17,048

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 current value added tax receivables. [Refer: Value added tax receivables]

+ 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 78
-Subparagraph b
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2025-en-b&anchor=para_78_b&doctype=Standard
-URIDate 2025-03-27

+ Details

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

- Definition

The amount of current assets that the entity does not separately disclose in the same statement or note. [Refer: Current assets]

+ References

+ Details

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

- Definition

The amount of current other receivables. [Refer: Other receivables]

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Note Effective 2027-01-01
-Name IFRS
-Number 19
-IssueDate 2025-01-01
-Paragraph B9
-Subparagraph b
-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_B9_b&doctype=Appendix&subtype=B
-URIDate 2025-03-27

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Note Expiry date 2027-01-01
-Name IAS
-Number 1
-IssueDate 2025-01-01
-Paragraph 78
-Subparagraph b
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2025-en-b&anchor=para_78_b&doctype=Standard
-URIDate 2025-03-27

+ Details

Name:	ifrs-full_OtherCurrentReceivables
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

- References

No definition available.

+ Details

Name:	ifrs-full_TradeAndOtherCurrentReceivablesAbstract
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- 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

Amount of CIR and other research tax credits receivable.

+ References

No definition available.

+ Details

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

- Definition

Amount of other current assets and receivables as of balance sheet date.

+ References

No definition available.

+ Details

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

- Definition

The amount of other tax receivables, classified as current.

+ References

No definition available.

+ Details

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