Mainland China Contribution Plan (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Defined Contribution Plan [Abstract]
Total provisions of employee benefits	$ 2,774	$ 2,192	$ 2,722

Amount of expense for employee benefit and equity-based compensation.

No definition available.

Name:	us-gaap_EmployeeBenefitsAndShareBasedCompensation
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration