Key Financial Data Of Reporting Company
| Concept | As at 2024-03-31 | 2024-01-01 to 2024-03-31 | 2023-01-01 to 2023-12-31 | As at 2023-12-31 | 2023-01-01 to 2023-03-31 | As at 2023-03-31 | 
|---|---|---|---|---|---|---|
| Key financial data of reporting company | ||||||
| Business results of reporting company | ||||||
| Net sales | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                29,534,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                6,963,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Ordinary profit (loss) | — | 
                                                -127,811,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -930,634,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -289,171,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net assets | 
                                                1,855,961,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                1,924,731,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                1,155,085,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Total assets | 
                                                1,921,517,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                2,052,252,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                1,236,872,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Basic earnings (loss) per share | — | 
                                                -3.33
                                                
                                             | 
                                                -26.82
                                                
                                             | — | 
                                                -9.61
                                                
                                             | — | 
| Diluted earnings per share | — |  |  | — |  | — | 
| Equity-to-asset ratio | 
                                                0.929
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.906
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.882
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             |