Net Income per Share

6 Months Ended

Jun. 30, 2013

Earnings Per Share [Abstract]

Net Income per Share

2. Net Income per Share

	Three Months Ended				Six Months Ended
	June 30,				June 30,
Net Income per Basic and Diluted Share:	2013		2012		2013		2012
(in thousands except per share amounts)
Numerator
Net income used to compute net income per basic share	$	93,742	$	73,502	$	147,213	$	113,686
Add back interest expense for convertible notes, net of estimated tax of approximately $3 for each of the three months ended June 30, 2013 and 2012, and $7 and $18 for the six months ended June 30, 2013 and 2012, respectively (see Note 9)	6		6		13		33
Net income used to compute net income per diluted share	$	93,748	$	73,508	$	147,226	$	113,719
Denominator
Total weighted-average shares used to compute net income per basic share	139,825		139,683		139,821		139,681
Restricted stock outstanding	75		100		71		84
Effect of dilutive stock options	19		15		19		15
Assumed conversion of Series 2012 Notes	8,304		2,252		8,693		2,189
Assumed conversion of May 2015 Notes	3,825		—		4,004		—
Assumed conversion of February 2015 Notes	176		163		176		921
Weighted-average shares used to compute net income per diluted share	152,224		142,213		152,784		142,890
Net income per basic share	$	0.67	$	0.53	$	1.05	$	0.81
Net income per diluted share	$	0.62	$	0.52	$	0.96	$	0.80

We compute net income per basic share using the weighted-average number of shares of common stock outstanding during the period less the weighted-average number of restricted stock shares that are subject to repurchase.

We compute net income per diluted share using the sum of the weighted-average number of common and common equivalent shares outstanding. Common equivalent shares used in the computation of net income per diluted share include shares that may be issued under our stock options and restricted stock awards, our February 2015 Notes, our Series 2012 Notes and our May 2015 Notes on a weighted average basis for the period that the notes were outstanding, including the effect of adding back interest expense and the underlying shares using the if-converted method. In the first quarter of 2012, $179.0 million aggregate principal of our February 2015 Notes was exchanged for our Series 2012 Notes.

In May 2011, we issued our May 2015 Notes, and in January and February 2012, we issued our Series 2012 Notes. The Series 2012 Notes and May 2015 Notes are net share settled, with the principal amount settled in cash and the excess settled in our common stock. The weighted average share adjustments related to our Series 2012 Notes and May 2015 Notes include the shares issuable in respect of such excess.

We excluded 20.4 million and 18.8 million shares for our warrants for the three months ended June 30, 2013 and 2012, respectively, and 20.4 million and 18.8 million shares for the six months ended June 30, 2013 and 2012, respectively, for warrants issued in 2011, because the exercise price of the warrants exceeded the VWAP of our common stock and thus, for the periods presented, no stock was issuable upon conversion. These securities could be dilutive in future periods. Our purchased call options, issued in 2011, will always be anti-dilutive and therefore 24.0 million and 22.1 million shares were excluded for the three months ended June 30, 2013 and 2012, respectively, and 24.0 million and 22.1 million shares were excluded for the six months ended June 30, 2013 and 2012, respectively, because they have no effect on diluted net income per share under GAAP. For information related to the conversion rates on our convertible debt, see Note 9.

For the three months ended June 30, 2013, we excluded approximately 139,000 and 28,000 shares underlying outstanding stock options and restricted stock awards, respectively, and 139,000 and 8,000 shares underlying outstanding stock options and restricted stock awards, respectively, were excluded for the six months ended June 30, 2013, calculated on a weighted average basis, from our net income per diluted share calculations because their effect was anti-dilutive.

For the three and six months ended June 30, 2012, we excluded approximately 174,000 shares underlying outstanding stock options, calculated on a weighted average basis, from our net income per diluted share calculations because their effect was anti-dilutive.