Note 5 - Stockholders' Equity and Dilutive Equity Instruments (Details Textual) - USD ($) $ / shares in Units, $ in Millions	1 Months Ended	3 Months Ended
	Jul. 31, 2023	Mar. 31, 2024	Feb. 29, 2024	Mar. 31, 2023
Share Repurchase Program [Member]
Share Repurchase Program, Authorized, Amount			$ 48.6
Stock Repurchased and Retired During Period, Shares (in shares)		38,831
Stock Repurchased and Retired During Period, Value		$ 3.5
Shares Acquired, Average Cost Per Share (in dollars per share)		$ 90.15
Out-of-the-money Warrants [Member]
Class of Warrant or Right, Outstanding (in shares)		783,009
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares)		861,310
New Creditor Warrants [Member]
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right (in shares)		1
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)		$ 0.001		$ 0.001
GLF Equity Warrants [Member]
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)		$ 100
Series A Warrants [Member]
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)	$ 57.06
Series B Warrants [Member]
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)	$ 62.28
Series A and B Warrants [Member]
Class of Warrant or Right, Outstanding (in shares)	2,000,000
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares)	1,900,000
Proceeds from Warrant Exercises	$ 111.5
Class of Warrant or Right, Expired (in shares)	3,100,000