Net Income Per Share (Tables)

9 Months Ended

Sep. 30, 2017

Earnings Per Share [Abstract]

Basic and Diluted Net Income (Loss) Per Share

The calculations of basic and diluted net income per share are as follows:

	Three Months Ended September 30,				Nine Months Ended September 30,
	2017		2016		2017		2016
Net income - basic	$	388,317	$	264,804	$	1,024,992	$	642,407
Effect of dilutive securities:
Convertible senior notes - interest expense and amortization of discount and note issuance costs	—		—		—		397
Net income - diluted	$	388,317	$	264,804	$	1,024,992	$	642,804
(Shares in thousands)
Weighted average shares - basic	106,706		104,833		106,108		104,586
Effect of dilutive securities:
Stock options	9,809		10,156		9,386		10,340
Restricted stock	513		479		500		474
Convertible senior notes	—		—		—		81
Warrants	—		998		—		1,086
Dilutive potential shares	10,322		11,633		9,886		11,981
Weighted average shares - diluted	117,028		116,466		115,994		116,567
Net income per share - basic	$	3.64	$	2.53	$	9.66	$	6.14
Net income per share - diluted	$	3.32	$	2.27	$	8.84	$	5.51

Antidilutive Securities

Shares which have been excluded from diluted per share amounts because their effect would have been antidilutive include the following:

	Three Months Ended September 30,		Nine Months Ended September 30,
(Shares in thousands)	2017	2016	2017	2016
Stock options	4,515	7,687	8,892	7,842
Restricted stock	—	19	—	19
Convertible senior notes	—	3	—	—