Note 11 - Subsequent Events

12 Months Ended

Dec. 31, 2021

Notes to Financial Statements

Subsequent Events [Text Block]

11. Subsequent Events

On

January 19, 2022,

we closed a private placement of

707,484

shares of common stock,

2,360,000

pre-funded warrants to purchase common stock, and accompanying warrants to purchase an aggregate of up to

3,067,484

shares of common stock. The warrants are exercisable immediately at an exercise price of

$3.26

per share and will expire

five

years from the date of issuance. Net proceeds after deducting placement agent commissions and other offering expenses were approximately

$9.2

million.