Note 8 - Capital Stock - Issuance of Common Stock (Details) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended						6 Months Ended		12 Months Ended
		Jun. 30, 2024	Mar. 31, 2024	Dec. 31, 2023	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Jun. 30, 2024		Dec. 31, 2023
Price per share (in dollars per share)	[1],[2]
Issuance of common stock pursuant to public offerings, net (in shares)	[1]							13,480,458		15,880,039
Issuance of common stock pursuant to public offerings, net		$ 100,698	$ 13,109			$ 47,355	$ 31,657	$ 113,807	[1],[3]	$ 159,438	[1],[3]
At the Market Offering Program [Member]
Price per share (in dollars per share)	[1],[2]	$ 8.4	$ 8.8	$ 0	$ 9.54	$ 9.95	$ 11.77	$ 8.4		$ 0
Issuance of common stock pursuant to public offerings, net (in shares)	[1]	11,990,383	1,490,075	0	8,432,086	4,757,953	2,690,000
Issuance of common stock pursuant to public offerings, net	[1],[3]	$ 100,698	$ 13,109	$ 0	$ 80,426	$ 47,355	$ 31,657

[1] The Company has entered into eleven equity distribution agreements, ten of which have either been terminated because all shares were sold or were replaced with a subsequent agreement.

[2] Weighted average price received per share is after deducting the underwriters’ discount, if applicable, and other offering costs.

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