Principal Accounting Policies - Property and Equipment, Net (Details) |
12 Months Ended |
|---|---|
Dec. 31, 2020 | |
| Electronic equipment | |
| Property, Plant and Equipment [Line Items] | |
| Property equipment, useful life | 3 years |
| Furniture, computers and office equipment | |
| Property, Plant and Equipment [Line Items] | |
| Property equipment, useful life | 3 years |
| Network equipment | |
| Property, Plant and Equipment [Line Items] | |
| Property equipment, useful life | 3 years |