Computation of Earnings Per Share

Basic earnings per share (“EPS”) is computed by dividing net income by the weighted-average number of common shares outstanding, including restricted stock units (“RSUs”) vested during the period. Diluted EPS is computed based on the sum of the weighted average number of common shares and potentially dilutive common shares outstanding during the period. Potentially dilutive common shares consist of shares issuable from stock options, unvested RSUs and the 3.25% Convertible Senior Notes due 2020 (“Convertible Senior Notes”). Potentially dilutive common shares from outstanding stock options and unvested RSUs are determined using the average share price for each period under the treasury stock method. Potentially dilutive shares from the Convertible Senior Notes are determined using the if-converted method. Under the provisions of the if-converted method, the Convertible Senior Notes are assumed to be converted and included in the denominator of the EPS calculation and the interest expense, net of tax, recorded in connection with the Convertible Senior Notes is added back to net income.

The Convertible Senior Notes have a dilutive impact when the average market price of the Company’s common stock exceeds the applicable conversion price of the notes. The Senior Convertible Notes became convertible on March 31, 2018 and remained convertible through March 31, 2019.

The following table reconciles net income and the weighted-average shares used in computing basic and diluted earnings per share in the respective periods (in thousands):



	Three months ended March 31,
	2019		2018
Numerator:
Net income used for basic earnings per share	$	24,844	$	33,958
Interest expense on Convertible Senior Notes, net of tax	791		2,144
Net income used for diluted earnings per share, if-converted method	$	25,635	$	36,102

Basic weighted-average common shares outstanding	39,704		35,236
Potentially dilutive shares issuable from Convertible Senior Notes, if-converted	1,825		4,957
Potentially dilutive shares issuable from stock options and unvested RSUs	1,378		1,755
Diluted weighted-average common shares outstanding, if-converted	42,907		41,948
Potentially dilutive shares excluded from calculation due to anti-dilutive effect	149		193

Potentially dilutive shares excluded from the calculation above represent stock options when the combined exercise price and unrecognized stock-based compensation are greater than the average market price for the Company’s common stock because their effect is anti-dilutive.