Fixed Assets, Net (Fixed Assets Stated at Cost) (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Property, Plant and Equipment [Line Items]
Fixed assets	$ 2,153	$ 4,787
Less: accumulated depreciation	(1,331)	(3,800)
Fixed assets, net	822	987
Office equipment and software
Property, Plant and Equipment [Line Items]
Fixed assets	$ 478	3,112
Property, Plant and Equipment, Useful Life	3 years
Leasehold improvements
Property, Plant and Equipment [Line Items]
Fixed assets	$ 395	395
Property, Plant and Equipment, Estimated Useful Lives	us-gaap:UsefulLifeShorterOfTermOfLeaseOrAssetUtilityMember, us-gaap:UsefulLifeTermOfLeaseMember
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Fixed assets	$ 1,280	$ 1,280
Property, Plant and Equipment, Useful Life	7 years