Shareholders equity - Share options (Details) - EUR (€)	3 Months Ended
Mar. 31, 2023	Mar. 31, 2022
Operating costs
Shareholders Equity
Compensation expenses	€ 1,095,000	€ 1,183,000
General and administrative costs
Shareholders Equity
Compensation expenses	739,000	641,000
Research and development costs
Shareholders Equity
Compensation expenses	€ 356,000	€ 542,000

The amount of expense arising from share-based payment transactions in which the goods or services received did not qualify for recognition as assets.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 2
-IssueDate 2022-03-24
-Paragraph 51
-Subparagraph a
-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=2&code=ifrs-tx-2022-en-r&anchor=para_51_a&doctype=Standard
-URIDate 2022-03-24

Name:	ifrs-full_ExpenseFromSharebasedPaymentTransactionsInWhichGoodsOrServicesReceivedDidNotQualifyForRecognitionAsAssets
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration