Note 11 - Earnings Per Share

Basic earnings per share is computed by dividing net loss available to common stockholders by the weighted-average number of shares of common stock outstanding during each period. Diluted earnings per share is based on the treasury stock method and computed by dividing net loss available to common stockholders by the diluted weighted-average shares of common stock outstanding during each period. The Company’s potentially dilutive shares include stock options and warrants for the shares of common stock. The potentially dilutive shares are considered to be common stock equivalents and are only included in the calculation of diluted net loss per share when the effect is dilutive. The investor warrants are treated as equity in the calculation of diluted earnings per share in both the computation of the numerator and denominator. The following table sets forth the calculations of basic and diluted earnings per share for the three months ended March 31, 2020 and 2019:


	Three Months Ended March 31,
	2020		2019
Net loss	$	(5,179,000)	$	(5,812,000)
Less: decrease in fair value of investor warrants		(831,000)		—
Loss available to common stockholders	$	(6,010,000)	$	(5,812,000)

Basic and diluted weighted-average common shares outstanding		159,054,000		111,104,000
Add: dilutive effect of equity instruments		1,504,000		—
Diluted weighted-average shares outstanding		160,558,000		111,104,000
Earnings per share – basic	$	(0.03)	$	(0.05)
Earnings per share – diluted	$	(0.04)	$	(0.05)

The potentially dilutive shares of common stock that have been excluded from the calculation of net loss per share because of the anti-dilutive effect are as following:


	Three Months Ended March 31,
	2020	2019
Outstanding stock options	5,948,000	5,426,000
Warrants to purchase shares of common stock	5,904,000	22,233,000
Total potentially dilutive shares of common stock	11,852,000	27,659,000