Note 15 - Stock Based Compensation (Tables)

9 Months Ended

Sep. 30, 2022

Notes Tables

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

	Three Months Ended September 30,			Nine Months Ended September 30,
	2022			2022
Risk-free interest rate	2.74%	-	2.88%	1.86%	-	3.02%
Expected term (in years)	5.30	-	5.31	5.19	-	6.11
Dividend yield		-			-
Expected volatility		117%		114%	-	128%

	Three Months Ended September 30,			Nine Months Ended September 30,
	2021			2021
Risk-free interest rate	0.89%	-	0.98%	0.89%	-	1.08%
Expected term (in years)	5.54	-	6.12	5.31	-	6.17
Dividend yield		-			-
Expected volatility	123%	-	126%	122%	-	130%

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

	Number of Underlying Shares			Weighted- Average Exercise Price Per Share		Weighted- Average Contractual Life Remaining in Years		Aggregate Intrinsic Value
Outstanding as of January 1, 2022		10,027		$	2.82		-
Granted		3,879			1.16		-		50,738
Exercised		-			-		-
Forfeited / cancelled		(200	)		0.91		-
Expired		-			-		-		-
Outstanding as of September 30, 2022		13,706			2.37		8.04	$	-
Exercisable as of September 30, 2022		9,354			2.65		7.52
Vested and expected to vest		13,706		$	2.37		8.04	$	-

Share-Based Payment Arrangement, Option [Member]

Notes Tables

Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Table Text Block]

	Three Months Ended September 30,				Nine Months Ended September 30,
	2022		2021		2022		2021
General and administrative	$	1,042	$	1,232	$	3,366	$	2,534
Research and development		624		562		1,877		1,114
Total stock compensation expense	$	1,666	$	1,794	$	5,243	$	3,648