Operating Income - Summary of Operating Income (Detail) - EUR (€) € in Thousands	6 Months Ended
Jun. 30, 2019	Jun. 30, 2018
Analysis of income and expense [abstract]
Revenues	€ 7,062	€ 7,283
Research tax credit	5,973	5,653
Subsidies		191
Other operating income	1,089	1,439
Total income	€ 7,062	€ 7,283

The income arising in the course of an entity's ordinary activities. Income is increases in economic benefits during the accounting period in the form of inflows or enhancements of assets or decreases of liabilities that result in an increase in equity, other than those relating to contributions from equity participants.

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+ Details