Basic net income per share is computed by dividing net income by the weighted average number of common shares outstanding during the period. Diluted net income per share is computed by dividing net income by the weighted average number of dilutive common shares outstanding during the period. Diluted shares outstanding are calculated by adding to the weighted average shares outstanding any potential dilutive securities outstanding for the period. Potential dilutive securities include stock options, restricted stock units, performance-based stock awards and shares to be purchased under the Company’s employee stock purchase plan. The Company’s basic and diluted net income per share for the three and nine months ended December 31, 2018 and 2017 were as follows (in thousands, except per share data):

	For the Three Months Ended December 31,				For the Nine Months Ended December 31,
	2018		2017		2018		2017
Basic Net Income Per Share
Net income	$	44,862	$	13,446	$	185,056	$	75,323

Basic weighted average shares outstanding		45,046		44,247		44,852		44,095

Basic net income per share	$	1.00	$	0.30	$	4.13	$	1.71

	For the Three Months Ended December 31,				For the Nine Months Ended December 31,
	2018		2017		2018		2017
Diluted Net Income Per Share
Net income	$	44,862	$	13,446	$	185,056	$	75,323

Basic weighted average shares outstanding		45,046		44,247		44,852		44,095
Effect of dilutive securities		1,090		1,622		1,295		1,636
Diluted weighted average shares outstanding		46,136		45,869		46,147		45,731

Diluted net income per share	$	0.97	$	0.29	$	4.01	$	1.65

For the three and nine months ended December 31, 2018, approximately 73,700 and 60,700 shares underlying out-of-the-money stock options, respectively, were excluded in the computation of diluted earnings per share because their effect would have been anti-dilutive. Also, approximately 104,000 restricted shares in each of the three and nine months ended December 31, 2018, respectively, related to performance-based awards for which milestones have not been met, were not included in the computation of diluted earnings per share.

For the three and nine months ended December 31, 2017, approximately 2,600 and 4,800 shares underlying out-of-the-money stock options, respectively, were excluded in the computation of diluted earnings per share because their effect would have been anti-dilutive. Also, approximately 185,000 restricted shares in each of the three and nine months ended December 31, 2017, respectively, related to performance-based and market-based awards for which milestones have not been met, were not included in the computation of diluted earnings per share.