Note 5 - Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 2023

Notes Tables

Fair Value, Liabilities Measured on Recurring and Nonrecurring Basis [Table Text Block]

	Financial liabilities at fair value as of December 31, 2023
(in thousands)	Level 1		Level 2		Level 3		Total
5% Notes	$	—	$	—	$	357	$	357
Total	$	—	$	—	$	357	$	357

	Financial liabilities at fair value as of December 31, 2022
	Level 1		Level 2		Level 3		Total
5% Notes	$	—	$	—	$	243	$	243
Total	$	—	$	—	$	243	$	243

Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block]

(in thousands)
Balance at January 1, 2022		360
Interest accrued on face value of 5% Notes		1,073
Change in fair value of Level 3 liabilities		(1,190	)
Balance at December 31, 2022	$	243
Interest accrued on face value of 5% Notes		1,133
Change in fair value of Level 3 liabilities		(1,019	)
Balance at December 31, 2023	$	357