Note 16 - Subsequent Events

12 Months Ended

Dec. 31, 2019

Notes to Financial Statements

Subsequent Events [Text Block]

1 6 . Subsequent Events

In

January 2020,

the board of directors approved the

2020

evergreen provision increasing the total stock reserved for issuance under the

2013

Plan by

2,639,926

shares from 

11,872,531

shares to a total of

14,512,457

shares, which was effective

January 1, 2020.

In

January

and

February 2020,

the holders of Series A convertible preferred stock converted

1,183,151

shares and

669,022

shares into common stock, respectively. As of

February 19, 2020,

all Series A convertible preferred stock had been converted into common stock and there are

no

remaining shares of Series A preferred stock outstanding.

In

February 2020,

a total of

1,026,240

shares of common stock were issued in connection with the exercise of Series A warrants for gross proceeds of approximately

$1,591,000.

In

February 2020,

a total of

45,473

shares of common stock were issued in connection with the exercise of Series B warrants for gross proceeds of approximately

$70,000.