Key Financial Data Of Group
| Concept | As at 2024-09-30 | 2024-04-01 to 2024-09-30 | 2023-04-01 to 2024-03-31 | As at 2024-03-31 | As at 2023-09-30 | 2023-04-01 to 2023-09-30 | 
|---|---|---|---|---|---|---|
| Key financial data of group | ||||||
| Business results of group | ||||||
| Ordinary profit (loss) | — | 
                                                -545,169,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -1,136,373,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -708,185,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Profit (loss) attributable to owners of parent | — | 
                                                -545,699,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -1,288,138,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -710,663,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Comprehensive income | — | 
                                                -545,699,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -1,288,138,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -710,663,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net assets | 
                                                1,000,348,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                353,666,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                934,995,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Total assets | 
                                                1,548,092,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                867,275,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,167,733,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Basic earnings (loss) per share | — | 
                                                -2.18
                                                
                                             | 
                                                -6.05
                                                
                                             | — | — | 
                                                -3.42
                                                
                                             | 
| Diluted earnings per share | — |  |  | — | — |  | 
| Equity-to-asset ratio | 
                                                0.599
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.322
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.734
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) operating activities | — | 
                                                -578,766,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -1,227,990,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -879,851,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net cash provided by (used in) investing activities | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -33,354,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -33,570,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net cash provided by (used in) financing activities | — | 
                                                1,149,384,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                671,365,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                677,229,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Cash and cash equivalents | 
                                                1,098,274,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                527,656,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                881,443,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — |