Subclassifications Of Assets, Liabilities And Equities [Abstract]
| Concept | As at 2024-12-31 | As at 2023-12-31 | As at 2022-12-31 | 
|---|---|---|---|
| Subclassifications of assets, liabilities and equities [abstract] | |||
| Property, plant and equipment [abstract] | |||
| Property, plant and equipment | 
                                                86,955,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                71,394,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | 
| Intangible assets and goodwill [abstract] | |||
| Intangible assets other than goodwill [abstract] | |||
| Intangible assets other than goodwill | 
                                                1,814,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                1,942,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | 
| Goodwill | 
                                                252,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                252,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | 
| Investments in subsidiaries, joint ventures and associates reported in separate financial statements [abstract] | |||
| Investments in subsidiaries, joint ventures and associates reported in separate financial statements | 
                                                0
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                0
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | 
| Investments accounted for using equity method [abstract] | |||
| Investments accounted for using equity method | 
                                                8,320,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                7,300,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | 
| Trade and other non-current receivables [abstract] | |||
| Trade and other non-current receivables | 
                                                692,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                122,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | 
| Trade and other receivables [abstract] | |||
| Trade receivables | 
                                                24,051,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                23,045,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | 
| Classes of current inventories [abstract] | |||
| Current inventories | 
                                                54,942,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                45,699,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | 
| Classes of current inventories, alternative [abstract] | |||
| Cash and cash equivalents [abstract] | |||
| Cash and cash equivalents | 
                                                38,416,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                39,955,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                23,772,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
| Borrowings [abstract] | |||
| Non-current portion of non-current borrowings | 
                                                43,055,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                32,259,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | 
| Current borrowings and current portion of non-current borrowings [abstract] | |||
| Current borrowings and current portion of non-current borrowings | 
                                                8,110,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                6,878,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | 
| Non-current portion of non-current borrowings, by type [abstract] | |||
| Current borrowings and current portion of non-current borrowings, by type [abstract] | |||
| Trade and other payables [abstract] | |||
| Trade and other payables | 
                                                31,205,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                28,435,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | 
| Miscellaneous non-current liabilities [abstract] | |||
| Other non-current liabilities | 
                                                2,123,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                2,324,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | 
| Issued capital [abstract] | |||
| Issued capital | 
                                                6,409,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                6,409,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | 
| Retained earnings [abstract] | |||
| Retained earnings | 
                                                94,904,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                86,589,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | 
| Net assets (liabilities) [abstract] | |||
| Assets | 
                                                223,535,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                197,933,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | 
| Liabilities | 
                                                92,381,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                76,548,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | 
| Net current assets (liabilities) [abstract] | |||
| Current assets | 
                                                124,362,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                115,818,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | 
| Current liabilities | 
                                                44,467,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                39,245,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | 
| Assets less current liabilities [abstract] |