Share-based compensation - Share-based Compensation Expense (Details) - USD ($) |
3 Months Ended | 6 Months Ended | ||
|---|---|---|---|---|
Jun. 30, 2026 |
Jun. 30, 2025 |
Jun. 30, 2026 |
Jun. 30, 2025 |
|
| Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items] | ||||
| Total share-based compensation expenses | $ 123,250 | $ 124,623 | $ 6,856 | $ 200,929 |
| Selling and distribution expenses | ||||
| Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items] | ||||
| Total share-based compensation expenses | 11,191 | 23,701 | 28,759 | 53,455 |
| General and administrative expenses | ||||
| Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items] | ||||
| Total share-based compensation expenses | $ 112,059 | $ 100,922 | $ (21,903) | $ 147,474 |