Note 1 - Summary of Significant Accounting Policies (Tables)

3 Months Ended

Mar. 31, 2022

Notes Tables

Property Plant and Equipment Useful Life [Table Text Block]

	Years
Computers, software, and office equipment	3	-	10
Leasehold improvements (1)	2	-	5
Manufacturing tooling	3	-	7
Laboratory equipment	4	-	10
Demo equipment		3

Fair Value Measurement Inputs and Valuation Techniques [Table Text Block]

	For the three months ended March 31,
	2022	2021
	Stock Options
Expected dividend yield	0.0%	0.0%
Expected stock price volatility	86.5%	84.8%
Risk-free interest rate	1.83% - 1.92%	0.93% - 1.45%
Expected life (years)	10	10
	Warrants
Expected dividend yield	n/a	0.0%
Expected stock price volatility	n/a	84.8%
Risk-free interest rate	n/a	0.42% - 0.69%
Expected life (years)	n/a	5 - 5.5