v3.26.1
Impairment testing (Details) - EUR (€)
€ in Thousands
Jun. 30, 2026
Dec. 31, 2025
Disclosure of impairment loss and reversal of impairment loss [line items]    
Assets € (388,276) € (398,836)
Accumulated impairment    
Disclosure of impairment loss and reversal of impairment loss [line items]    
Assets 16,100 20,800
Accumulated impairment | Leasehold improvements    
Disclosure of impairment loss and reversal of impairment loss [line items]    
Assets 2,500 2,600
Accumulated impairment | Manufacturing equipment    
Disclosure of impairment loss and reversal of impairment loss [line items]    
Assets 5,600 10,100
Accumulated impairment | Right-of-use assets    
Disclosure of impairment loss and reversal of impairment loss [line items]    
Assets 3,200 3,300
Accumulated impairment | R&D costs    
Disclosure of impairment loss and reversal of impairment loss [line items]    
Assets 3,700 3,600
Accumulated impairment | Internal development costs    
Disclosure of impairment loss and reversal of impairment loss [line items]    
Assets € 1,200 € 1,200