Note 1 - Organization and Significant Accounting Policies (Details Textual) - USD ($) $ / shares in Units, $ in Thousands			3 Months Ended				4 Months Ended	7 Months Ended	9 Months Ended			12 Months Ended
	Mar. 07, 2023	Oct. 29, 2021	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Sep. 30, 2022	Oct. 28, 2021	Sep. 30, 2023	Sep. 30, 2023		Sep. 30, 2022	Dec. 31, 2022		Aug. 30, 2022
Stock Issued During Period, Shares, New Issues (in shares)									15,880,039			3,885,048
Stock Issued During Period, Value, New Issues			$ 80,426	$ 47,355	$ 31,657				$ 159,438	[1]		$ 40,580	[1]
Proceeds from Issuance of Common Stock									159,438		$ 0
Direct Operating Costs			$ 193			$ 175			$ 531		$ 683
Common Stock, Par or Stated Value Per Share (in dollars per share)			$ 0.01					$ 0.01	$ 0.01			$ 0.01		$ 0.01
Reclassification to Conform To Current Period [Member]
Direct Operating Costs			$ 900						$ 1,600
June 2021 Equity Distribution Agreement [Member]
Equity Agreement, Maximum Number of Shares Issuable (in shares)							250,000,000
October 2021 Equity Distribution Agreement [Member]
Stock Issued During Period, Shares, New Issues (in shares)		9,742,188
Stock Issued During Period, Value, New Issues		$ 151,800
Proceeds from Issuance of Common Stock		$ 149,300
March 2023 Equity Distribution Agreement [Member]
Equity Agreement, Maximum Number of Shares Issuable (in shares)	250,000,000
Stock Issued During Period, Shares, New Issues (in shares)								13,190,039
Stock Issued During Period, Value, New Issues								$ 129,800
Proceeds from Issuance of Common Stock								$ 127,800

[1] Net proceeds are net of the underwriters' discount, if applicable, and other offering costs.