Note 8 - 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	2021	2022	2021
Risk-free interest rate	2.85% - 2.90%	0.84%	1.91% - 2.90%	0.46% - 0.92%
Dividend yield	0%	0%	0%	0%
Expected term (years)	3.25 - 6.00	5.00	3.25 - 6.00	5.00
Expected volatility	45.9% - 48.1%	46.8%	45.8% - 48.5%	47.1% - 92.6%