Research and development costs (Details) - EUR (€)	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Research and Development costs
Research and development costs	€ 46,491,000	€ 29,514,000	€ 31,153,000

The amount of expenditure directly attributable to research or development activities, recognised in profit or loss.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 38
-IssueDate 2019-01-01
-Paragraph 126
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=38&code=ifrs-tx-2019-en-r&anchor=para_126&doctype=Standard
-URIDate 2019-03-27

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