Net Income Per Share

9 Months Ended

Sep. 30, 2019

9. Net Income Per Share

Net income per share was calculated as follows:

	Three Months Ended September 30,				Nine Months Ended September 30,
(in thousands, except per share data)	2019		2018		2019		2018
Net income - basic and diluted	$	53,789	$	50,764	$	3,012	$	3,033
Weighted-average common shares outstanding:
Basic		91,859		90,555		91,440		90,064
Effect of dilutive securities:
Employee stock purchase program		11		7		22		2
Stock options		2,466		3,352		2,572		3,322
Restricted stock		461		629		392		558
2024 Notes		1,277		2,255		805		1,326
Diluted		96,074		96,798		95,231		95,272
Net income per share:
Basic	$	0.59	$	0.56	$	0.03	$	0.03
Diluted	$	0.56	$	0.52	$	0.03	$	0.03

Convertible debt instruments that may be settled entirely or partly in cash (such as the 2024 Notes) may, in certain circumstances where the borrower has the ability and intent to settle in cash, be accounted for under the treasury stock method. We issued the 2024 Notes with a combination settlement feature, which we have the ability and intent to use upon conversion of the 2024 Notes, to settle the principal amount of debt for cash and the excess of the principal portion in shares of our common stock. As a result, of the approximately 6.8 million shares underlying the 2024 Notes, only the shares required to settle the excess of the principal portion are considered under the treasury stock method.

Shares which have been excluded from diluted per share amounts because their effect would have been anti-dilutive consisted of the following:

Three Months Ended

September 30,

Nine Months Ended

September 30,

(in thousands)

2019

2018

2019

2018

Stock options, restricted stock and convertible senior notes

2,347

882

2,189

823