Accounting Principles - Foreign currency transactions and Segment information (Details) € in Millions	12 Months Ended
Dec. 31, 2020 EUR (€)
Accounting Principles
Foreign currency expense amount	€ 2.5
Foreign currency expenses as a percentage of operating expenses	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:	num:percentItemType
Balance Type:	na
Period Type:	duration