Note 6 - Stockholders' Equity

9 Months Ended

Sep. 30, 2021

Notes to Financial Statements

Stockholders' Equity Note Disclosure [Text Block]

6. Stockholders’ Equity

Public offering of common stock

On July 2, 2021, the Company closed an underwritten public offering of 3,333,334 shares of common stock for a purchase price of $3.00. The gross proceeds from this offering were approximately $10.0 million. The net proceeds were approximately $9.1 million.

Warrants exercised and expired

During the nine months ended September 30, 2021, the Company issued a total of 228,939 shares of common stock for a total of approximately $1.0 million, resulting from exercises of outstanding warrants. During the same period, the Company issued an additional 190,588 shares of common stock resulting from the net, cashless, exercise of outstanding warrants to purchase 536,140 shares. Warrants to purchase a total of 573,339 shares of common stock, all having an exercise price of $5.00 per share, expired during the nine months ended September 30, 2021. Additionally, warrants to purchase 108,550 shares of common stock, with an exercise price of $15.00 expired during the nine months ended September 30, 2021.

Public offering of common stock and warrants

On September 1, 2020, the Company closed an underwritten public offering of 2,545,454 shares of its common stock and warrants to purchase an aggregate of up to the same number of additional shares of common stock. The warrants are exercisable for a period of five years from the date of issuance at an initial exercise price of $4.54. The gross proceeds from the offering were approximately $10.5 million. The net proceeds were approximately $9.3 million. After exercises, registered warrants to purchase common stock totaling 2,306,516 remained on September 30, 2021.

Shares reserved

The following shares of common stock were reserved for future issuance as of date indicated:

	September 30, 2021
Stock options outstanding		2,489,136
Restricted stock units		16,185
Shares available for grant under equity incentive plan		1,328,363
Common shares issuable under outstanding common stock purchase warrants		5,109,501
		8,943,185