Note 5 - Share-based Compensation (Tables)

3 Months Ended

Mar. 31, 2022

Notes Tables

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

Risk-Free interest rate	1.40% - 1.44%
Expected dividend yield	—%
Expected stock price volatility	61.3%
Expected life of options (in years)	5.50 - 6.25

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

						Weighted-Average
				Weighted-Average		Remaining Contractual		Aggregate Intrinsic
	Shares			Exercise Price		Term (Years)		Value
Outstanding at December 31, 2021		4,774,215		$	3.04		6.14	$	8,413,444
Granted (1)		715,825			4.81
Exercised		(35,000	)		1.21
Expired		(30,000	)		6.87
Canceled		—			—
Outstanding at March 31, 2022		5,425,040		$	3.27		6.48	$	3,931,706
Exercisable at March 31, 2022		4,070,223		$	2.79		5.61	$	3,827,242

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

	Three Months Ended March 31,
	2022		2021
General and administrative	$	388,662	$	377,052
Research and development		65,129		44,019
Total	$	453,791	$	421,071