Note 8 - Stock Based Awards (Tables)

9 Months Ended

Sep. 30, 2023

Notes Tables

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

						Weighted
						Average
				Weighted		Remaining		Aggregate
				Average		Contractual		Intrinsic
	Number of			Exercise		Life		Value
	Shares			Price		(in years)		(in thousands)
Balances, January 1, 2023		4,570,432		$	2.50
Options granted		3,207,654			1.69
Options expired		(43,838	)		6.18
Options forfeited		(2,385,156	)		1.83
Balances, September 30, 2023		5,349,092		$	2.29		6.6	$	-
Outstanding and expected to vest as of September 30, 2023		5,028,804		$	2.32		6.4	$	-
Exercisable as of September 30, 2023		3,300,921		$	2.54		5.0	$	-

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

	September 30,			September 30,
	2023			2022
Expected volatility		115.9	%		113.0	%
Risk-free interest rate		3.5	%		2.1	%
Dividend yield		0.0	%		0.0	%
Expected life (in years)		6.0			6.0