Principal Accounting Policies - Narrative (Details)
|
12 Months Ended |
|
|
Dec. 31, 2022
USD ($)
Segment
|
Dec. 31, 2021
USD ($)
|
Dec. 31, 2020
USD ($)
|
Jan. 01, 2021
USD ($)
|
| Finite-Lived Intangible Assets [Line Items] |
|
|
|
|
| Cash equivalents |
$ 21,900,000
|
$ 0
|
|
|
| Short-term investments |
382,039,000
|
469,636,000
|
|
|
| Cash and cash equivalents restricted cash, short-term investments, long-term investments and held-for-sale assets |
468,300,000
|
|
|
|
| Impairment Losses, Investments |
8,277,000
|
626,000
|
|
|
| Impairment of long-lived assets (excluding goodwill) |
0
|
0
|
$ 0
|
|
| Impairment of long-lived assets |
0
|
0
|
0
|
|
| Deferred offering costs |
$ 0
|
2,300,000
|
|
|
| Value added tax rate |
6.00%
|
|
|
|
| Advances from customers |
$ 8,352,000
|
9,068,000
|
|
|
| Contract with customer, liability, revenue recognized |
5,600,000
|
700,000
|
900,000
|
|
| Marketing and advertising costs |
3,400,000
|
3,200,000
|
1,600,000
|
|
| Deferred tax liabilities, uncertain tax positions |
0
|
0
|
0
|
|
| Dividends |
$ 0
|
0
|
0
|
|
| Number of operating segments | Segment |
1
|
|
|
|
| Number of reportable segments | Segment |
1
|
|
|
|
| Operating lease right-of-use assets |
$ 2,344,000
|
7,436,000
|
|
$ 6,500,000
|
| Operating lease, liability |
$ 2,272,000
|
|
|
$ 6,500,000
|
| Measurement period |
1 year
|
|
|
|
| Contract with customer, Asset after allowance for credit loss |
$ 600,000
|
1,000,000.0
|
|
|
| Short-Term Investments [Member] |
|
|
|
|
| Finite-Lived Intangible Assets [Line Items] |
|
|
|
|
| Impairment Losses, Investments |
$ 0
|
$ 0
|
$ 0
|
|
| No Individual Customer | Revenue Benchmark [Member] | Customer Concentration Risk [Member] |
|
|
|
|
| Finite-Lived Intangible Assets [Line Items] |
|
|
|
|
| Concentration risk, percentage |
10.00%
|
10.00%
|
10.00%
|
|
| HONG KONG |
|
|
|
|
| Finite-Lived Intangible Assets [Line Items] |
|
|
|
|
| Percentage of deposits held by financial institutions |
49.00%
|
|
|
|
| SINGAPORE |
|
|
|
|
| Finite-Lived Intangible Assets [Line Items] |
|
|
|
|
| Percentage of deposits held by financial institutions |
34.00%
|
|
|
|
| PRC |
|
|
|
|
| Finite-Lived Intangible Assets [Line Items] |
|
|
|
|
| Percentage of deposits held by financial institutions |
16.00%
|
|
|
|
| Other International |
|
|
|
|
| Finite-Lived Intangible Assets [Line Items] |
|
|
|
|
| Percentage of deposits held by financial institutions |
1.00%
|
|
|
|
| Minimum |
|
|
|
|
| Finite-Lived Intangible Assets [Line Items] |
|
|
|
|
| Finite-lived intangible asset, useful life |
3 years
|
|
|
|
| Maximum |
|
|
|
|
| Finite-Lived Intangible Assets [Line Items] |
|
|
|
|
| Finite-lived intangible asset, useful life |
5 years
|
|
|
|