v3.26.3
Capital and Reserves - Additional Information (Detail) - EUR (€)
€ / shares in Units, € in Thousands
6 Months Ended
Jun. 30, 2026
Jun. 25, 2026
Apr. 08, 2026
Dec. 31, 2025
Jun. 30, 2025
Dec. 31, 2024
Capital and Reserves [Line Items]            
Issued capital € 82,519 [1]   € 10,600 € 66,260    
Number of shares outstanding 24,716,536          
Par value per share   € 2.4        
Amount of offset of losses against share premium         € 531,113  
Accumulated deficit € (722,485) [1]     (674,858)    
Reserve of share based payments 16,110     17,495    
Foreign currency translation reserve 368 [1]     (3,335)    
Equity (59,641) [1]     (31,461) 36,138 [2] € 62,578
Capitalized development costs 32,871     31,393    
Share premium 8,619 [1]     7,443    
Additional share premium         11,859  
Capital reduction reserves 542,972 [1]     542,972 542,972  
Share premium         € 531,113  
ARES and Coil [Member]            
Capital and Reserves [Line Items]            
Equity 865     € 865    
Class A Ordinary Shares [Member]            
Capital and Reserves [Line Items]            
Issued capital € 56,534          
Number of shares outstanding 23,552,996          
Par value per share € 2.4          
Common stock, voting rights Class A Shares provide holders with one (1) vote per share.          
Class B Ordinary Shares [Member]            
Capital and Reserves [Line Items]            
Issued capital € 8,521          
Number of shares outstanding 355,040          
Par value per share € 24          
Common stock, voting rights Class B Shares provide holders with ten (10) votes per share          
Class C Ordinary Shares [Member]            
Capital and Reserves [Line Items]            
Issued capital € 17,464          
Number of shares outstanding 808,500          
Par value per share € 21.6          
Common stock, voting rights Class C Shares provide holders with nine (9) votes per share          
[1] Unaudited
[2] Unaudited