Note 14—Earnings (Loss) Per Share

Basic earnings per share is computed by dividing net income or loss attributable to all classes of common stockholders of the Company by the weighted average number of shares of all classes of common stock outstanding during the applicable period. Diluted earnings per share is computed in the same manner as basic earnings per share, except that the number of shares is increased to include restricted stock still subject to risk of forfeiture and to assume exercise of potentially dilutive stock options using the treasury stock method, unless the effect of such increase is anti-dilutive.

The weighted-average number of shares used in the calculation of basic and diluted earnings per share attributable to the Company’s common stockholders consists of the following:

	Three Months Ended September 30,				Nine Months Ended September 30,
	2018		2017		2018		2017
	(in thousands)
Basic weighted-average number of shares		24,805		23,567		24,895		23,495
Effect of dilutive securities:
Stock options and warrants		181		—		68		—
Non-vested restricted Class B common stock		456		591		262		—
Diluted weighted-average number of shares		25,442		24,158		25,225		23,495

The following shares were excluded from the diluted earnings per share computation:

	Three Months Ended September 30,				Nine Months Ended September 30,
	2018		2017		2018		2017
	(in thousands)
Stock options and warrants		341		383		341		383
Non-vested restricted Class B common stock		—		—		—		1,205
Shares excluded from the calculation of diluted earnings per share		341		383		341		1,588

In the nine months ended September 30, 2017, the diluted loss per share computation equals basic loss per share because the Company had a net loss and the impact of the assumed exercise of stock options and the vesting of restricted stock would have been anti-dilutive. In the three months ended September 30, 2018 and 2017 and nine months ended September 30, 2018 , stock options with an exercise price that was greater than the average market price of the Company’s stock during the period were excluded from the diluted loss per share computation.

Employees of the Company that were previously granted restricted stock of Afek and Genie Mongolia, Inc. have the right to exchange the restricted stock, upon vesting of such shares, into shares of the Company’s Class B common stock. These exchanges, if elected, would be based on the relative fair value of the shares exchanged. The number of shares of the Company’s stock issuable in an exchange is not currently determinable. If shares of the Company’s stock are issued upon such exchange, the Company’s earnings per share may be diluted in future periods.