v3.25.4
Share-based compensation - Text Details (Detail)
€ in Thousands, $ in Millions
1 Months Ended 12 Months Ended
Apr. 30, 2023
yr
Dec. 31, 2025
EUR (€)
shares
yr
performanceCondition
Dec. 31, 2025
USD ($)
yr
Dec. 31, 2024
EUR (€)
shares
Dec. 31, 2024
USD ($)
Dec. 31, 2023
EUR (€)
shares
Dec. 31, 2022
Dec. 31, 2021
Dec. 31, 2025
USD ($)
shares
performanceCondition
Dec. 31, 2024
USD ($)
shares
Share-based compensation [Line Items]                    
Total cost   € 148,000   € 104,000   € 97,000        
Comparison group for performance shares   20 20 20 20 20        
Risk free interest rate, share options granted   1.82% 1.82%              
Expected volatility, share options granted   38.00% 38.00%              
Volatility assumption, measurement period   10 years             10 years  
EUR                    
Share-based compensation [Line Items]                    
Intrinsic value of options exercised   € 800   € 15            
Proceeds from exercise of options   € 8,400   € 84            
Number of share options exercisable in share-based payment arrangement (in shares) | shares   2,966,493   39,983         2,966,493 39,983
Number of share options (in shares) | shares   2,966,493   3,396,539   3,660,000     2,966,493 3,396,539
Weighted average remaining contractual term in years   6 years 8 months 12 days 6 years 8 months 12 days 8 years 1 month 6 days 8 years 1 month 6 days          
Weighted average remaining contractual term of exercisable share options in years       4 months 24 days 4 months 24 days          
Intrinsic value of options exercisable   € 3,200   € 90            
Intrinsic value of options outstanding   7,600                
US Dollar                    
Share-based compensation [Line Items]                    
Intrinsic value of options exercised | $     $ 0.5   $ 0.0          
Proceeds from exercise of options   € 4,400   € 0            
Number of share options exercisable in share-based payment arrangement (in shares) | shares   1,381,643   0         1,381,643 0
Number of share options (in shares) | shares   1,381,643   1,637,764   1,929,000     1,381,643 1,637,764
Weighted average remaining contractual term in years   5 years 9 months 18 days 5 years 9 months 18 days 8 years 8 years          
Weighted average remaining contractual term of exercisable share options in years       0 years 0 years          
Intrinsic value of options exercisable | $                 $ 3.7 $ 0.0
Intrinsic value of options outstanding | $                 $ 1.5  
Income tax deduction   € 1,000   € 0            
TSR | Top of range                    
Share-based compensation [Line Items]                    
Vesting requirements, weight of metric   40.00% 40.00%     50.00% 50.00% 50.00%    
EPS                    
Share-based compensation [Line Items]                    
Vesting requirements, weight of metric   40.00% 40.00%     40.00% 40.00% 40.00%    
SDG | Bottom of range                    
Share-based compensation [Line Items]                    
Vesting requirements, weight of metric   20.00% 20.00%     10.00% 10.00% 10.00%    
Share-based compensation                    
Share-based compensation [Line Items]                    
Share-based compensation cost   € 141,000                
Restricted shares                    
Share-based compensation [Line Items]                    
Vesting period   3 years             3 years  
Unrecognized compensation costs related to non-vested shares   € 67,000   73,000   € 63,000        
Cost recognition period (weighted average)   1 year 9 months 18 days 1 year 9 months 18 days              
Performance share plans                    
Share-based compensation [Line Items]                    
Vesting period   3 years             3 years  
Number of applicable conditions | performanceCondition   3             3  
Unrecognized compensation costs related to non-vested shares   € 116,000   € 128,000   € 102,000        
Cost recognition period (weighted average)   1 year 9 months 18 days 1 year 9 months 18 days              
Employee stock purchase plan                    
Share-based compensation [Line Items]                    
Total cost   € 6,000                
Retention option plan                    
Share-based compensation [Line Items]                    
Vesting period   2 years             2 years  
Option life, share options granted | yr 10 10 10