The amount of outstanding funds that the entity is obligated to repay.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 1
-IssueDate 2020-01-01
-Paragraph 55
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_55&doctype=Standard
-URIDate 2020-01-01

+ Details

Name:	ifrs-full_Borrowings
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

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

- Definition

The amount of liabilities related to the entity's leases. Lease is a contract, or part of a contract, that conveys the right to use an underlying asset for a period of time in exchange for consideration.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 16
-IssueDate 2020-01-01
-Paragraph 47
-Subparagraph b
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=16&code=ifrs-tx-2020-en-r&anchor=para_47_b&doctype=Standard
-URIDate 2020-01-01

+ Details

Name:	ifrs-full_LeaseLiabilities
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The amount of loans received.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 1
-IssueDate 2020-01-01
-Paragraph 112
-Subparagraph c
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_112_c&doctype=Standard
-URIDate 2020-01-01

+ Details

Name:	ifrs-full_LoansReceived
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

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

+ References

+ Details

Name:	ifrs-full_OtherBorrowings
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The cash outflow for payment of lease liabilities, classified as financing activities. [Refer: Lease liabilities]

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Name IAS
-Number 7
-IssueDate 2020-01-01
-Paragraph 17
-Subparagraph e
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=7&code=ifrs-tx-2020-en-r&anchor=para_17_e&doctype=Standard
-URIDate 2020-01-01

+ Details

Name:	ifrs-full_PaymentsOfLeaseLiabilitiesClassifiedAsFinancingActivities
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The cash inflow from borrowings obtained. [Refer: Borrowings]

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Name IAS
-Number 7
-IssueDate 2020-01-01
-Paragraph 17
-Subparagraph c
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=7&code=ifrs-tx-2020-en-r&anchor=para_17_c&doctype=Standard
-URIDate 2020-01-01

+ Details

Name:	ifrs-full_ProceedsFromBorrowingsClassifiedAsFinancingActivities
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The cash outflow for repayments of current borrowings. [Refer: Current borrowings]

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 7
-IssueDate 2020-01-01
-Paragraph 17
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=7&code=ifrs-tx-2020-en-r&anchor=para_17&doctype=Standard
-URIDate 2020-01-01

+ Details

Name:	ifrs-full_RepaymentsOfCurrentBorrowings
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Period up to which the maturity term of the borrowings can be extended.

+ References

No definition available.

+ Details

Name:	iva_BorrowingsMaximumExtensionTerm
Namespace Prefix:	iva_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of loans obtained by the company.

+ References

No definition available.

+ Details

Name:	iva_BorrowingsNumberOfLoansObtained
Namespace Prefix:	iva_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

The amount of increase (decrease) in borrowings.

+ References

No definition available.

+ Details

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

- Details

Name:	ifrs-full_BorrowingsByNameAxis=iva_FinancingFromSyndicateOfFrenchBanksMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

Name:	ifrs-full_InitiallyAppliedIFRSsAxis=iva_Ifrs16Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Debt - Debt and borrowings (Details) € in Thousands	1 Months Ended	12 Months Ended
Debt - Debt and borrowings (Details) € in Thousands	May 31, 2020 EUR (€) loan	Dec. 31, 2020 EUR (€)	Dec. 31, 2019 EUR (€)	Jan. 01, 2019 EUR (€)	Dec. 31, 2018 EUR (€)	Dec. 31, 2017 EUR (€)
Disclosure of detailed information about borrowings [line items]
Bank borrowings		€ 9,992	€ 74		€ 220
Other loans and similar borrowings		62	3		5
Lease liabilities		2	37
Total Debt		10,055	114	€ 392	€ 225	€ 482
Increase (Decrease) in borrowings			100
Loan obtained		9,979
Payments of lease liabilities, classified as financing activities		€ 26	130
Repayments of borrowings			100
Financing from a syndicate of French banks
Disclosure of detailed information about borrowings [line items]
Number of loans obtained \| loan	3
Loan obtained	€ 10,000
Extension of term of debt	4 years	4 years
Socit Gnrale
Disclosure of detailed information about borrowings [line items]
Total Debt		€ 13
IFRS 16
Disclosure of detailed information about borrowings [line items]
Lease liabilities			167
Payments of lease liabilities, classified as financing activities			€ 100