Segment information - Additional information (Details) - EUR (€) € in Thousands	Jun. 30, 2021	Dec. 31, 2020
Segment information
Property, plant and equipment	€ 16,411	€ 16,590
Right-of-use assets.	20,558	22,120
United States
Segment information
Property, plant and equipment	460	516
Right-of-use assets.	€ 449	€ 709

Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes of the table.

No definition available.

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- Definition

The amount of tangible assets that: (a) are held for use in the production or supply of goods or services, for rental to others, or for administrative purposes; and (b) are expected to be used during more than one period.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition

The amount of assets that represent a lessee's right to use an underlying asset for the lease term. Underlying asset is an asset that is the subject of a lease, for which the right to use that asset has been provided by a lessor to a lessee.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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