Accounting Principles - Foreign currency transactions and Segment information (Details) - EUR (€) € in Millions	12 Months Ended
Dec. 31, 2021	Dec. 31, 2020
Accounting Principles
Foreign currency expense amount	€ 13.5	€ 2.5
Foreign currency expenses as a percentage of operating expenses	21.00%	7.00%

The percentage amount of operating expenses that were paid in a currency other than the reporting currency.

No definition available.

Name:	iva_PurchasesInForeignCurrencyAsPercentageOfOperatingExpenses
Namespace Prefix:	iva_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration