Note 4 - Shareholders' Equity (Details Textual) - At The Market Program [Member] - USD ($) $ in Millions	3 Months Ended
	Jun. 30, 2023	Mar. 31, 2023	Apr. 28, 2022
Number of Shares Authorized for Issuance (in shares)	17,900,000		200,000,000.0
Forward Sales Agreements, Shares (in shares)	2,087,231	228,690
Forward Sales Agreements, Block Sales, Shares (in shares)	1,744,549
Forward Sales Agreements, Proceeds If Settled	$ 149.7