The expected volatility of the share price used to calculate the fair value of the share options granted. Expected volatility is a measure of the amount by which a price is expected to fluctuate during a period. The measure of volatility used in option pricing models is the annualised standard deviation of the continuously compounded rates of return on the share over a period of time.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 2
-IssueDate 2021-01-01
-Paragraph 47
-Subparagraph a
-Clause i
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=2&code=ifrs-tx-2021-en-r&anchor=para_47_a_i&doctype=Standard
-URIDate 2021-03-24

+ Details

Name:	ifrs-full_DescriptionOfExpectedVolatilityShareOptionsGranted
Namespace Prefix:	ifrs-full_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

The option life of share options granted.

+ References

+ Details

Name:	ifrs-full_DescriptionOfOptionLifeShareOptionsGranted
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	duration

- Definition

The implied yield currently available on zero-coupon government issues of the country in whose currency the exercise price for share options granted is expressed, with a remaining term equal to the expected term of the option being valued (based on the option's remaining contractual life and taking into account the effects of expected early exercise). [Refer: Government [member]]

+ References

+ Details

Name:	ifrs-full_DescriptionOfRiskFreeInterestRateShareOptionsGranted
Namespace Prefix:	ifrs-full_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

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

+ References

No definition available.

+ Details

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

- Definition

The number of other equity instruments (ie other than share options) granted in a share-based payment arrangement.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 2
-IssueDate 2021-01-01
-Paragraph 47
-Subparagraph b
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=2&code=ifrs-tx-2021-en-r&anchor=para_47_b&doctype=Standard
-URIDate 2021-03-24

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IFRS
-Number 2
-IssueDate 2021-01-01
-Paragraph 45
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=2&code=ifrs-tx-2021-en-r&anchor=para_45&doctype=Standard
-URIDate 2021-03-24

+ Details

Name:	ifrs-full_NumberOfInstrumentsOtherEquityInstrumentsGranted
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	duration

- Definition

The weighted average exercise price of other equity instruments (ie other than share options) outstanding in a share-based payment arrangement. [Refer: Weighted average [member]]

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IFRS
-Number 2
-IssueDate 2021-01-01
-Paragraph 45
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=2&code=ifrs-tx-2021-en-r&anchor=para_45&doctype=Standard
-URIDate 2021-03-24

+ Details

Name:	ifrs-full_WeightedAverageExercisePriceOfOtherEquityInstrumentsOutstandingInSharebasedPaymentArrangement2019
Namespace Prefix:	ifrs-full_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant

- Definition

The weighted average fair value at the measurement date of granted equity instruments other than share options. [Refer: Weighted average [member]]

+ References

+ Details

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

- Definition

Number of securities into which each warrant or right may be converted. For example, but not limited to, each warrant may be converted into two shares.

+ References

No definition available.

+ Details

Name:	iva_IfrsClassOfWarrantOrRightNumberOfSecuritiesCalledByEachWarrantOrRight
Namespace Prefix:	iva_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

Period which the right to exercise an award is no longer contingent on satisfaction of either a service condition, market condition or a performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

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

- Definition

Subscription premium price per share of other equity instruments granted in share-based payment arrangement.

+ References

No definition available.

+ Details

Name:	iva_SubscriptionPremiumPricePerShareOfOtherEquityInstrumentsGranted
Namespace Prefix:	iva_
Data Type:	dtr-types:perShareItemType
Balance Type:	na
Period Type:	instant

- Details

Name:	ifrs-full_TypesOfSharebasedPaymentArrangementsAxis=iva_Bsa2017PlanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	iva_IfrsVestingAxis=iva_IfrsShareBasedPaymentArrangementTrancheOneMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	iva_IfrsVestingAxis=iva_IfrsShareBasedPaymentArrangementTrancheTwoMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	iva_IfrsVestingAxis=iva_IfrsShareBasedPaymentArrangementTrancheThreeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_TypesOfSharebasedPaymentArrangementsAxis=iva_Bsa2018PlanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_TypesOfSharebasedPaymentArrangementsAxis=iva_Bsa20181PlanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_RangeAxis=ifrs-full_TopOfRangeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_RangeAxis=ifrs-full_BottomOfRangeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_TypesOfSharebasedPaymentArrangementsAxis=iva_NewShareWarrantPlansBsa2019Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_TypesOfSharebasedPaymentArrangementsAxis=iva_NewShareWarrantPlansBsa2019BisMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_TypesOfSharebasedPaymentArrangementsAxis=iva_NewShareWarrantPlansBsa2019TerMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_TypesOfSharebasedPaymentArrangementsAxis=iva_NewBsa2021ShareWarrantPlanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_TypesOfSharebasedPaymentArrangementsAxis=iva_ShareWarrantPlansBsa2017Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Shareholders' Equity - Characteristics of BSA share warrant plans (Details)		12 Months Ended
	Apr. 16, 2021	Dec. 31, 2021 EUR (€) item Y € / shares shares	Dec. 31, 2020 € / shares	Dec. 31, 2019 € / shares
BSA - 2017 plan
Disclosure of terms and conditions of share-based payment arrangement [line items]
Subscription premium price per share ()		€ 0.534
Exercise price (in euros)		€ 6.67	€ 6.67	€ 6.67
BSA - 2017 plan \| Tranche one
Disclosure of terms and conditions of share-based payment arrangement [line items]
Vesting period		1 year
BSA - 2017 plan \| Tranche two
Disclosure of terms and conditions of share-based payment arrangement [line items]
Vesting period		2 years
BSA - 2017 plan \| Tranche three
Disclosure of terms and conditions of share-based payment arrangement [line items]
Vesting period		3 years
BSA - 2018 plan
Disclosure of terms and conditions of share-based payment arrangement [line items]
Exercise price (in euros)		€ 6.07	€ 6.07	€ 6.07
BSA 2018-1
Disclosure of terms and conditions of share-based payment arrangement [line items]
Issued \| item		126,000
Number of shares per BSA \| shares		1
Subscription premium price per share ()		€ 0.48
Exercise price (in euros)		€ 6.067
Fair value per BSA at grant date () \| €		€ 1.98
Expected volatility		40.00%
Average life (years) \| Y		6
Risk free rate		0.30%
BSA 2018-1 \| Top of range [Member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Vesting period		3 years
BSA 2018-1 \| Bottom of range [Member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Vesting period		1 year
BSA 2019
Disclosure of terms and conditions of share-based payment arrangement [line items]
Vesting period		1 year
Issued \| item		10,000
Number of shares per BSA \| shares		1
Subscription premium price per share ()		€ 0.18
Exercise price (in euros)		€ 2.20
Fair value per BSA at grant date () \| €		€ 0.48
Expected volatility		40.00%
Average life (years) \| Y		5.5
Risk free rate		0.33%
BSA 2019 bis
Disclosure of terms and conditions of share-based payment arrangement [line items]
Vesting period		1 year
Issued		10,000	10,000
Number of shares per BSA \| shares		1
Subscription premium price per share ()		€ 0.29
Exercise price (in euros)		€ 3.68	€ 3.68
Fair value per BSA at grant date () \| €		€ 0.90
Expected volatility		40.00%
Average life (years) \| Y		6
Risk free rate		0.00%
BSA 2019 ter
Disclosure of terms and conditions of share-based payment arrangement [line items]
Issued		36,000	36,000
Number of shares per BSA \| shares		1
Subscription premium price per share ()		€ 0.29
Exercise price (in euros)		€ 3.68	€ 3.68
Fair value per BSA at grant date () \| €		€ 0.90
Expected volatility		40.00%
Average life (years) \| Y		6
Risk free rate		0.00%
BSA 2019 ter \| Top of range [Member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Vesting period		3 years
BSA 2019 ter \| Bottom of range [Member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Vesting period		1 year
BSA 2021
Disclosure of terms and conditions of share-based payment arrangement [line items]
Vesting period		3 years
Issued	50,000	50,000
Number of shares per BSA \| shares		1
Subscription premium price per share ()		€ 2.45
Exercise price (in euros)		€ 11.74
Expected volatility		64.00%
Average life (years) \| Y		5
Risk free rate		0.60%
BSA 2021 \| Top of range [Member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Fair value per BSA at grant date () \| €		€ 3.2
BSA 2021 \| Bottom of range [Member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Fair value per BSA at grant date () \| €		€ 3.0
BSA - 2017
Disclosure of terms and conditions of share-based payment arrangement [line items]
Issued \| item		195,000
Number of shares per BSA \| shares		1
Exercise price (in euros)		€ 6.675
Fair value per BSA at grant date () \| €		€ 2.47
Expected volatility		40.00%
Average life (years) \| Y		6
Risk free rate		0.22%