EARNINGS PER SHARE:

Basic earnings per share are calculated by dividing net income by the weighted-average shares of common stock outstanding during the period. Diluted earnings per share are calculated by dividing net income by the weighted-average shares of common stock and dilutive common equivalent shares outstanding during the period. Dilutive common equivalent shares included in this calculation consist of dilutive shares issuable upon the assumed exercise of outstanding common stock options, the assumed vesting of outstanding restricted stock units, the assumed issuance of awards under the stock purchase plan and contingently issuable performance-based awards, as computed using the treasury stock method.

A summary of the earnings per share calculation is as follows:



	Year Ended December 31,
(in thousands, except per share amounts)	2018		2017		2016
Basic earnings per share:
Net income	$	69,984	$	27,609	$	48,898
Weighted-average common shares	29,456		29,674		28,925
Basic earnings per share	$	2.38	$	0.93	$	1.69
Diluted earnings per share ⁽¹⁾:
Net income	$	69,984	$	27,609	$	48,898
Weighted-average common shares	29,456		29,674		28,925
Effect of dilutive securities:
Employee stock plans	691		871		694
Diluted weighted-average common shares	30,147		30,545		29,619
Diluted earnings per share	$	2.32	$	0.90	$	1.65

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(1)

The Company includes the shares underlying performance-based awards in the calculation of diluted earnings per share if the performance conditions have been satisfied as of the end of the reporting period and excludes such shares when the necessary conditions have not been met. The Company has included in the 2018, 2017 and 2016 calculations those shares that were contingently issuable upon the satisfaction of the performance conditions as of the end of the respective periods.

In the years ended December 31, 2018, 2017, and 2016, no outstanding stock awards were determined to be anti-dilutive and therefore were excluded from the computation of diluted earnings per share.