Note 15 - Stock Based Compensation (Tables)

12 Months Ended

Dec. 31, 2022

Notes Tables

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

	Year Ended December 31,
	2022		2021
Risk-free interest rate		1.86% - 3.56%		0.89% - 1.08%
Expected term (in years)		5.19 - 6.11		5.31 - 6.17
Dividend yield		-		-
Expected volatility		103% - 128%		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		4,079		1.13			$	51
Forfeited		(200)		0.91
Exercised		-		-
Expired		-		-				-
Outstanding as of December 31, 2022		13,906	$	2.35		7.82	$	-
Exercisable as of December 31, 2022		10,283	$	2.59		7.41	$	-
Vested and expected to vest		13,906	$	2.35		7.82	$	-

Share-Based Payment Arrangement, Option [Member]

Notes Tables

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

	Year Ended December 31,
	2022		2021
General and administrative	$	4,395	$	3,676
Research and development		2,393		1,591
Total stock compensation expense	$	6,788	$	5,267