Segment and Geographic Information - Summary of Property, Equipment and Software, Net, and Right-of-use Assets, Net (Details) - USD ($) |
Sep. 30, 2025 |
Dec. 31, 2024 |
Dec. 31, 2023 |
|---|---|---|---|
| Revenue from External Customer [Line Items] | |||
| Property, Equipment and Software, Net, and Right-of-use Assets, Net | $ 5,082 | $ 3,544 | $ 2,973 |
| Taiwan | |||
| Revenue from External Customer [Line Items] | |||
| Property, Equipment and Software, Net, and Right-of-use Assets, Net | 3,747 | 2,139 | 762 |
| China | |||
| Revenue from External Customer [Line Items] | |||
| Property, Equipment and Software, Net, and Right-of-use Assets, Net | 711 | 593 | 774 |
| North America | |||
| Revenue from External Customer [Line Items] | |||
| Property, Equipment and Software, Net, and Right-of-use Assets, Net | 601 | 786 | 1,400 |
| Rest of the World | |||
| Revenue from External Customer [Line Items] | |||
| Property, Equipment and Software, Net, and Right-of-use Assets, Net | $ 23 | $ 26 | $ 37 |