Contract assets and contract liabilities - Additional Information (Details) - CNY (¥) ¥ in Thousands |
6 Months Ended | ||
|---|---|---|---|
Jun. 30, 2025 |
Jun. 30, 2024 |
Dec. 31, 2024 |
|
| Disclosure of Contract Assets Explanatory [Line Items] | |||
| Receivables from contracts with customers | ¥ 22,814 | ¥ 31,917 | |
| Revenue that was included in contract liability balance at beginning of period | 2,000 | ¥ 12,500 | |
| Not later than one year [member] | |||
| Disclosure of Contract Assets Explanatory [Line Items] | |||
| Receivables from contracts with customers | ¥ 0 | ¥ 561 | |