Fair value measurements - Schedule of Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation (Detail) |
Jun. 30, 2025 |
Dec. 31, 2024 |
Dec. 31, 2023 |
|---|---|---|---|
| Measurement Input, Discount Rate [Member] | |||
| Fair Value Measurement Inputs and Valuation Techniques [Line Items] | |||
| Significant Unobservable Inputs | 8 | 0.075 | 0.11 |
| Measurement Input, Price Volatility [Member] | |||
| Fair Value Measurement Inputs and Valuation Techniques [Line Items] | |||
| Significant Unobservable Inputs | 56.6 | 0.65 | 0.665 |
| Measurement Input, Risk Free Interest Rate [Member] | |||
| Fair Value Measurement Inputs and Valuation Techniques [Line Items] | |||
| Significant Unobservable Inputs | 4.1 | 0.041 | 0.042 |