Key Financial Data Of Group
| Concept | As at 2024-06-30 | 2023-07-01 to 2024-06-30 | As at 2023-06-30 | 2022-07-01 to 2023-06-30 | 2021-07-01 to 2022-06-30 | As at 2022-06-30 | 2020-07-01 to 2021-06-30 | As at 2021-06-30 | As at 2020-06-30 | 2019-07-01 to 2020-06-30 | 
|---|---|---|---|---|---|---|---|---|---|---|
| Key financial data of group | ||||||||||
| Business results of group | ||||||||||
| Ordinary profit (loss) | — | 
                                                -1,208,349,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -1,283,062,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -854,327,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -555,112,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -573,686,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net assets | 
                                                2,340,867,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                1,932,152,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                250,688,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                437,972,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                236,902,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Total assets | 
                                                2,432,855,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                2,085,999,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                790,709,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                1,295,610,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,263,283,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net assets per share | 
                                                127.87
                                                
                                             | — | 
                                                115.77
                                                
                                             | — | — | 
                                                13.85
                                                
                                             | — | 
                                                40.35
                                                
                                             | 
                                                21.58
                                                
                                             | — | 
| Basic earnings (loss) per share | — | 
                                                -67.90
                                                
                                             | — | 
                                                -83.03
                                                
                                             | 
                                                -88.31
                                                
                                             | — | 
                                                -70.01
                                                
                                             | — | — | 
                                                -83.64
                                                
                                             | 
| Diluted earnings per share | — |  | — |  |  | — |  | — | — |  | 
| Equity-to-asset ratio | 
                                                0.947
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.910
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.202
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.272
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.120
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
| Rate of return on equity | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Price-earnings ratio | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Net cash provided by (used in) operating activities | — | 
                                                -1,280,192,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -1,398,936,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -719,814,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -688,572,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -552,921,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net cash provided by (used in) investing activities | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                182,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -72,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net cash provided by (used in) financing activities | — | 
                                                1,538,270,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                2,272,621,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                282,751,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                728,800,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                901,659,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Cash and cash equivalents | 
                                                1,888,200,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                1,617,795,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                737,775,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                1,154,754,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,112,334,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Number of employees | 
                                                11
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                12
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                11
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                12
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                11
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
| Average number of temporary employees | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — |