Note 8 - Stock-based Compensation (Tables)

3 Months Ended

Mar. 31, 2022

Notes Tables

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

	Three Months Ended March 31,
	2022		2021
Research and development	$	58,892	$	33,000
General and administrative		219,239		148,280
Total stock-based compensation expense	$	278,131	$	181,280

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

	Number of Options			Weighted average exercise price per share		Weighted average remaining contractual life (in years)		Aggregate intrinsic value
Balance at January 1, 2022		72,454		$	265.85
Granted		48,300			12.00
Cancelled/forfeited		(4,190	)		75.33
Outstanding at March 31, 2022		116,564		$	164.31		8.89	$	23,163
Exercisable at March 31, 2022		52,849		$	346.79		8.13	$	1,956
Vested and expected to vest at March 31, 2022		116,564		$	164.31		8.89	$	23,163

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

Expected term (in years)	5.7
Risk-free interest rate	1.7	%
Expected volatility	134.7	%
Dividend yield	—

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

	Number of Units			Weighted average grant date fair value
Balance at January 1, 2022		5,509		$	34.78
Vested (1)		(327	)		25.50
Outstanding at March 31, 2022		5,182		$	35.36