Net Income Per Share (Tables)

6 Months Ended

Jun. 30, 2016

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 June 30,
	2016		2015
Net income - basic and diluted	$	196,218	$	194,643
(Shares in thousands)
Weighted average shares - basic	104,633		102,886
Effect of dilutive securities:
Stock options	10,141		9,438
Restricted stock	473		474
Warrants	984		2,461
Dilutive potential shares	11,598		12,373
Weighted average shares - diluted	116,231		115,259
Net income per share - basic	$	1.88	$	1.89
Net income per share - diluted	$	1.69	$	1.69

	Six Months Ended June 30,
	2016		2015
Net income - basic	$	377,603	$	270,664
Effect of dilutive securities:
Convertible senior notes - interest expense related to contractual coupon interest rate and amortization of discount and note issuance costs	373		—
Net income - diluted	$	377,976	$	270,664
(Shares in thousands)
Weighted average shares - basic	104,462		102,558
Effect of dilutive securities:
Stock options	10,433		9,441
Restricted stock	471		471
Convertible senior notes	121		—
Warrants	1,130		2,492
Dilutive potential shares	12,155		12,404
Weighted average shares - diluted	116,617		114,962
Net income per share - basic	$	3.61	$	2.64
Net income per share - diluted	$	3.24	$	2.35

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 June 30,
(Shares in thousands)	2016	2015
Stock options	7,904	3,366
Restricted stock	20	—
Convertible senior notes	96	1,539

	Six Months Ended June 30,
(Shares in thousands)	2016	2015
Stock options	7,830	3,370
Restricted stock	19	—
Convertible senior notes	—	1,733