Note 10 - Stockholders' Equity, Stock Options and Warrants (Tables)

6 Months Ended

Jun. 30, 2024

Notes Tables

Schedule of Share-Based Payment Award, Stock Options, Valuation Assumptions [Table Text Block]

	Six Months Ended June 30,
	2024		2023
	Stock Options
Expected dividend yield		-		0.0%
Expected stock price volatility		-		90.8% –91.6%
Risk-free interest rate		-		3.38% –3.72%
Expected life (in years)		-		10

Share-Based Payment Arrangement, Activity [Table Text Block]

	Stock Options					Warrants
	Number of Shares			Average Exercise Price		Number of Shares			Average Exercise Price
Outstanding as of December 31, 2023		47,664		$	82.23		1,806,589		$	21.52
Issued		-			-		-			-
Forfeited		(233	)		4.67		-			-
Expired		(1,019	)		105.99		(77,285	)		33.86
Outstanding as of June 30, 2024		46,412		$	82.09		1,729,304		$	20.97