Note 4 - Warrants and Equity (Tables)

9 Months Ended

Sep. 30, 2024

Notes Tables

Schedule of Warrants or Rights, Assumptions Used [Table Text Block]

	September 30, 2024	December 31, 2023
Risk-free interest rate	3.6% to 4.5%	3.8% to 5.4%
Volatility	78.7% to 111.5%	79.5% to 108.7%
Expected life (years)	0.4 to 5.0	0.3 to 5.0
Dividend yield	—%	—%

Schedule of Warrant Activity [Table Text Block]

	Number of Shares			Range of Warrant Exercise				Weighted Average		Weighted Average Remaining Contractual
	Under Warrant			Price per Share				Exercise Price		Life (Years)
Balance at January 1, 2024		1,082,895		$	9.60	$	157.50	$	24.32		5.1
Granted		5,056,054		$	2.23	$	2.79	$	2.24		2.9
Expired warrants		(75,909	)	$	99.00	$	99.00	$	99.00		—
Balance at September 30, 2024		6,063,040		$	2.23	$	94.50	$	12.90		3.1
Exercisable at September 30, 2024		1,006,986		$	2.23	$	94.50	$	8.75		4.1