Shareholders' Equity - Liquidity agreement (Details)		12 Months Ended
Jan. 19, 2018	Dec. 31, 2020
Shareholders' Equity
Liquidity Agreement Term	12 months	12 months

Number of days used to determine liquidity agreement term in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

No definition available.

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