Note 18—Income (Loss) Per Share

Basic income (loss) per share is computed by dividing net income (loss) attributable to common stockholders by the sum of the weighted-average number of common shares outstanding and the weighted-average number of shares issuable under the common stock warrants, representing 354 thousand shares, 354 thousand shares, and 347 thousand shares for the years ended December 31, 2018, 2017, and 2016, respectively. The common stock warrants are included in the calculation of basic income (loss) per share because they are issuable for minimal consideration. The following table sets forth the computation of basic and diluted loss per share (in thousands, except per share amounts):



	Year Ended December 31,
	2018		2017		2016
Net income (loss)	$	39,427	$	72,621	$	(45,835	)
Less: Undistributed income allocated to participating securities (1)	556		878		—
Net income (loss) attributable to common stockholders	38,871		71,743		(45,835		)
Plus: Net income effect of convertible securities	—		—		—
Numerator for diluted income (loss) per common share	$	38,871	$	71,743	$	(45,835	)

Basic weighted-average common stock shares outstanding	45,726		45,543		42,349
Add dilutive effects of common stock equivalents (2)	29		40		—
Diluted weighted-average common stock shares outstanding	45,755		45,583		42,349

Basic income (loss) per common share	$	0.85	$	1.58	$	(1.08	)
Diluted income (loss) per common share	$	0.85	$	1.57	$	(1.08	)

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(1)	Participating securities includes restricted stock that has been issued but has not yet vested.


(2)	Entities with a net loss from continuing operations are prohibited from including potential common shares in the computation of diluted per share amounts. We have utilized the basic shares outstanding to calculate both basic and diluted loss per share for the year ended December 31, 2016.

For the year ended December 31, 2018, our calculation of dilutive shares outstanding excluded 68 thousand shares of unvested restricted stock and 1.3 million stock options. For the year ended December 31, 2017, our calculation of dilutive shares outstanding excluded 65 thousand shares of unvested restricted stock and 1.3 million stock options. For the year ended December 31, 2016, our calculation of dilutive shares outstanding excluded 451 thousand shares of unvested restricted stock and 1.3 million stock options.

As discussed in Note 12—Debt, we have the option of settling the 5.00% Convertible Senior Notes issued in June 2016 in cash or shares of common stock, or any combination thereof, upon conversion. For the years ended December 31, 2018, 2017, and 2016, diluted income (loss) per share was determined using the if-converted method. Our calculation of diluted shares outstanding for years ended December 31, 2018, 2017, and 2016 excluded 6.4 million common stock equivalents, as the effect would be anti-dilutive.