Income taxes - Changes in the balance of gross unrecognized tax benefits (Details) ¥ in Thousands, $ in Thousands |
12 Months Ended | |||
|---|---|---|---|---|
|
Dec. 31, 2025
CNY (¥)
|
Dec. 31, 2025
USD ($)
|
Dec. 31, 2024
CNY (¥)
|
Dec. 31, 2023
CNY (¥)
|
|
| Income taxes | ||||
| Beginning balance | ¥ 117 | $ 17 | ¥ 117 | ¥ 117 |
| Increase of unrecognized tax benefits taken in prior years | 40,375 | 5,774 | 0 | 0 |
| Ending balance | ¥ 40,492 | $ 5,791 | ¥ 117 | ¥ 117 |