Key Financial Data Of Group
| Concept | 2024-01-01 to 2024-03-31 | As at 2024-03-31 | 2023-10-01 to 2024-03-31 | As at 2023-09-30 | 2022-10-01 to 2023-09-30 | 2023-01-01 to 2023-03-31 | As at 2023-03-31 | 2022-10-01 to 2023-03-31 | 
|---|---|---|---|---|---|---|---|---|
| Key financial data of group | ||||||||
| Business results of group | ||||||||
| Net sales | — | — | 
                                                3,850,757,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                5,757,306,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                2,581,864,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Ordinary profit (loss) | — | — | 
                                                -1,800,989,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                412,045,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                152,812,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Profit (loss) attributable to owners of parent | — | — | 
                                                -1,966,480,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                205,448,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                77,203,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Comprehensive income | — | — | 
                                                -1,966,869,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                206,317,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                76,843,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net assets | — | 
                                                319,167,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                2,258,471,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                2,102,539,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Total assets | — | 
                                                2,964,337,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                5,101,192,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                3,436,280,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Basic earnings (loss) per share | 
                                                -536.32
                                                
                                             | — | 
                                                -493.58
                                                
                                             | — | 
                                                52.06
                                                
                                             | 
                                                7.93
                                                
                                             | — | 
                                                19.71
                                                
                                             | 
| Diluted earnings per share | — | — |  | — | 
                                                51.09
                                                
                                             | — | — | 
                                                19.22
                                                
                                             | 
| Equity-to-asset ratio | — | 
                                                0.0617
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.4197
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.5853
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) operating activities | — | — | 
                                                -858,505,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -70,504,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                131,722,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net cash provided by (used in) investing activities | — | — | 
                                                -152,851,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -470,533,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -461,339,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net cash provided by (used in) financing activities | — | — | 
                                                454,808,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                452,750,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                500,600,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Cash and cash equivalents | — | 
                                                809,095,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                1,365,645,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                1,624,915,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — |