Note 12 - Subsequent Events

3 Months Ended

Mar. 31, 2021

Notes to Financial Statements

Subsequent Events [Text Block]

12.

Subsequent Events

In

April 2021,

we commenced a registered securities offering pursuant to an At-Market Issuance Sales Agreement (the “Sales Agreement”) with B. Riley Securities, Inc. (“B. Riley”). The Sales Agreement provides that we

may

offer and sell our common stock having an aggregate offering price of up to

$25.0

million from time to time (the “Offering”) through or to B. Riley, acting as our sales agent or principal. We did

not

receive any proceeds from the Offering during the

first

quarter of

2021.