Note 8 - Equity Plans and Related Equity Activities (Tables)

3 Months Ended

12 Months Ended

Mar. 31, 2023

Dec. 31, 2022

Notes Tables

Share-Based Payment Arrangement, Cost by Plan [Table Text Block]

	Three Months Ended March 31,
	2023		2022
Research and development	$	97	$	119
General and administrative		390		302
Total stock-based compensation	$	487	$	421

	Year Ended December 31,
	2022		2021
Research and development	$	583	$	292
General and administrative		1,300		851
Total stock-based compensation	$	1,883	$	1,143