Note 4. Computation of Net Earnings per Share

Basic earnings per share is computed by dividing income available to common stockholders (the numerator) by the weighted‑average number of common shares outstanding (the denominator) for the period. The computation of diluted earnings per share is similar to basic earnings per share, except that the denominator is increased by the number of additional common shares that would have been outstanding if the potentially dilutive common shares issuable for stock options and restricted stock units had been issued, calculated using the treasury stock method.

The components of net earnings per share are as follows:


	Three months ended				Nine months ended
	September 30,				September 30,
	2018		2017		2018		2017
	(in thousands, except per share amounts)
Net income available to common stockholders	$	8,838	$	11,841	$	37,422	$	35,279
Weighted average common shares outstanding used in computing basic income per share		32,365		31,274		32,225		30,550
Incremental options and RSUs		1,608		2,250		1,807		2,498
Weighted average common shares used in computing diluted net income per share		33,973		33,524		34,032		33,048
Net income per share
Basic	$	0.27	$	0.38	$	1.16	$	1.15
Diluted	$	0.26	$	0.35	$	1.10	$	1.07

Diluted weighted average common shares outstanding does not include options and restricted stock units outstanding to purchase 0.3 million and four thousand common equivalent shares for the three month periods ended September 30, 2018 and 2017, respectively, and does not include options and restricted stock units outstanding to purchase eleven thousand and 0.2 million common equivalent shares for the nine month periods ended September 30, 2018 and 2017, respectively, as their effect would have been anti-dilutive.