Net income (loss) per share

Basic net income (loss) per share is computed by dividing net income (loss) by the weighted average number of common shares outstanding during the period. Diluted net income (loss) per share is computed by dividing net income (loss) by the weighted average number of common shares and dilutive potential common shares outstanding during the period. Dilutive potential common shares include incremental common shares issuable upon the vesting of unvested restricted stock units and the exercise of outstanding stock options, calculated using the treasury stock method.

For the three months ended September 30, 2018 and the nine months ended September 30, 2018 and 2017, we excluded all restricted stock units and stock options from the per share calculations as such securities were anti-dilutive. For the three months ended September 30, 2017, we excluded stock options with an exercise price greater than the average price from the per share calculations. The weighted average number of restricted stock units and stock options that were excluded totaled approximately 13,258,000 and 3,460,000 for the three months ended September 30, 2018 and 2017, respectively, and approximately 13,338,000 and 13,367,000 for the nine months ended September 30, 2018 and 2017, respectively.

The following table presents the computations of basic and diluted net income (loss) per share (in thousands, except per share amounts):



	Three Months Ended September 30,					Nine Months Ended September 30,
	2018			2017		2018			2017
Net income (loss)	$	(67,446	)	$	50,021	$	(102,888	)	$	(66,329	)

Weighted average common shares outstanding - basic	159,304			143,357		156,799			142,876
Dilutive potential common shares	—			4,711		—			—
Weighted average common shares outstanding - diluted	159,304			148,068		156,799			142,876

Net income (loss) per share - basic	$	(0.42	)	$	0.35	$	(0.66	)	$	(0.46	)
Net income (loss) per share - diluted	$	(0.42	)	$	0.34	$	(0.66	)	$	(0.46	)