Income (Loss) per Share

Basic income (loss) per share is computed by dividing net income (loss) 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 during each of the three months ended March 31, 2019 and March 31, 2018. 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 income (loss) per share (in thousands, except per share amounts):



	Three Months Ended March 31,
	2019		2018
Net income	$	61,092	$	15,185
Less: Undistributed income allocated to participating securities (1)	693		192
Net income attributable to common stockholders	60,399		14,993
Plus: Net income effect of convertible securities	2,756		—
Numerator for diluted income per common share	$	63,155	$	14,993

Basic weighted-average common stock shares outstanding	49,127		45,634
Plus: dilutive effects of common stock equivalents	6,423		43
Diluted weighted-average common stock shares outstanding	55,550		45,677

Basic income per common share	$	1.23	$	0.33
Diluted income per common share	$	1.14	$	0.33

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

For the three months ended March 31, 2019, our calculation of diluted shares outstanding excluded 359 thousand shares of unvested restricted stock and 1.9 million stock options. For the three months ended March 31, 2018, our calculation of diluted shares outstanding excluded 46 thousand shares of unvested restricted stock and 1.3 million stock options.

As discussed in Note 9—Debt, we have the option of settling the 5.00% Convertible Senior Notes in cash or shares of common stock, or any combination thereof, upon conversion. For the three months ended March 31, 2019 and March 31, 2018, diluted income (loss) per share was determined using the if-converted method. Our calculation of diluted shares outstanding for the three months ended March 31, 2018 excluded 6.4 million common stock equivalents, as the effect would be anti-dilutive.