Note 2 - Investments and Fair Value Measurements (Details Textual)	1 Months Ended				3 Months Ended			6 Months Ended
	Jun. 30, 2025 USD ($)		May 31, 2025 USD ($)	May 31, 2023 USD ($)	Jun. 30, 2025 USD ($)		Jun. 30, 2024 USD ($)	Jun. 30, 2025 USD ($)		Jun. 30, 2024 USD ($)	Dec. 31, 2024 USD ($)	Apr. 30, 2023
Debt Securities, Available-for-Sale	$ 0				$ 0			$ 0			$ 0
Restricted Cash, Current	8,100,000				8,100,000			8,100,000			10,978,000
Equity Method Investments	$ 14,330,000				$ 14,330,000			$ 14,330,000			$ 14,066,000
Companies Accounted For Under Equity Method Investments	3				3			3			3
Equity Method Investment, Other-than-Temporary Impairment					$ 0		$ 0	$ 0		$ 0
Investments [Member]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	$ 0				$ 0			$ 0
Jia Mei Investment [Member]
Subsidiary, Ownership Percentage, Noncontrolling Owner	10.00%	[1]		10.00%	10.00%	[1]		10.00%	[1]
Jia Mei Investment [Member]
Equity Method Investment, Other-than-Temporary Impairment			$ 145,000
Equity Method Investment, Ownership Percentage												25.00%
Proceeds from Sale of Equity Method Investments				$ 827,000
Equity Method Investment, Realized Gain (Loss) on Disposal				575,000
Equity Method Investment, Realized Gain (Loss) On Adjustment To Fair Value	$ 145,000			$ 383,000
Other Assets [Member]
Equity Method Investments	14,300,000				$ 14,300,000			$ 14,300,000			$ 14,100,000
Other Assets [Member] | Jia Mei Investment [Member]
Equity Method Investments	$ 406,000				$ 406,000			$ 406,000

[1] In May 2023, we sold 15% of our equity investments in Jia Mei to a third party. We now own 10% of Jia Mei and account for it under the fair value method.