Schedule of Cash and Marketable Securities by Significant Investment Category (Details) - USD ($)	9 Months Ended	12 Months Ended
	Sep. 30, 2023	Dec. 31, 2023	Dec. 31, 2022
Cash and Cash Equivalents [Line Items]
Cost		$ 33,919,000	$ 68,914,000
Unrealized Gain/(Loss)		(17,325,000)	(17,976,000)
Fair Value		16,594,000	50,938,000
Cash and Cash Equivalents		6,615,000	19,290,000
Current marketable securities		9,979,000	27,307,000
Investments			4,341,000
Fair Value, Inputs, Level 2 [Member] | Convertible Securities [Member]
Cash and Cash Equivalents [Line Items]
Cost			1,023,000
Unrealized Gain/(Loss)
Fair Value			1,023,000
Cash and Cash Equivalents
Current marketable securities
Investments			1,023,000
Fair Value, Inputs, Level 2 [Member] | Warrant [Member]
Cash and Cash Equivalents [Line Items]
Cost			3,318,000
Unrealized Gain/(Loss)
Fair Value			3,318,000
Cash and Cash Equivalents
Current marketable securities
Investments			3,318,000
Cash [Member]
Cash and Cash Equivalents [Line Items]
Cost		6,545,000	19,226,000
Unrealized Gain/(Loss)
Fair Value		6,545,000	19,226,000
Cash and Cash Equivalents		6,545,000	19,226,000
Current marketable securities
Investments
Money Market Funds [Member] | Fair Value, Inputs, Level 1 [Member]
Cash and Cash Equivalents [Line Items]
Cost		70,000	64,000
Unrealized Gain/(Loss)
Fair Value		70,000	64,000
Cash and Cash Equivalents		70,000	64,000
Current marketable securities
Investments
Marketable Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Cash and Cash Equivalents [Line Items]
Cost		27,304,000	45,283,000
Unrealized Gain/(Loss)		(17,325,000)	(17,976,000)
Fair Value		9,979,000	27,307,000
Cash and Cash Equivalents
Current marketable securities		$ 9,979,000	27,307,000
Investments