Summary of Significant Accounting Policies (Narrative) (Details) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2024 USD ($) Segment Portfolio	Dec. 31, 2023 USD ($)
Summary Of Significant Accounting Policies [Line Items]
Allowance for doubtful accounts as of December 31, 2022	$ 126	$ 132
Accumulated deficit	(231,227)	(233,026)
Reserve balance for credit loss	100	100
Deferred revenue	300	$ 500
Notes receivable, principal amount	37,300
Borrower's note balance	$ 23,400
Borrower's note balance, percentage	63.00%	62.00%
Due from borrower	$ 23,400
Number of distinct portfolio purchases and loan agreements | Portfolio	11
Beginning balance of reserve for credit losses as of January 1, 2023	$ 100	$ 100
Allowance for credit loss	$ (643)
Consolidated [Member]
Summary Of Significant Accounting Policies [Line Items]
Number of reporting segment | Segment	3
Accounting Standards Update 2022-02 [Member]
Summary Of Significant Accounting Policies [Line Items]
Percentage of service revenue that is recognized over a period of time against total revenue	1.3861%
Note receivable outstanding	$ 600	700
Accounting Standards Update 2022-02 [Member] | Notes Receivable [Member]
Summary Of Significant Accounting Policies [Line Items]
Percentage of service revenue that is recognized over a period of time against total revenue	3.60%
Accounting Standards Update 2022-02 [Member] | Equity Method Investments [Member]
Summary Of Significant Accounting Policies [Line Items]
Percentage of service revenue that is recognized over a period of time against total revenue	1.3861%
Credit loss rate	4.40%
Allowance for credit loss	$ 900	$ 900