Basic and diluted earnings per share are calculated as follows (in thousands, except per share amounts):

		Three Months Ended				Six Months Ended
			September 30,				September 30,
		2011		2010		2011		2010

		(unaudited)				(unaudited)
Basic:
	Weighted average shares		31,383		31,149		31,445		31,269
	Net income	$	10,947	$	6,881	$	20,923	$	13,407
	Net income per share	$	0.35	$	0.22	$	0.67	$	0.43
Diluted:
	Weighted average shares		31,383		31,149		31,445		31,269
	Common equivalent shares from stock options		1,162		474		1,224		486
	Weighted average shares used in diluted per share calculation		32,545		31,623		32,669		31,755
	Net income	$	10,947	$	6,881	$	20,923	$	13,407
	Net income per share	$	0.34	$	0.22	$	0.64	$	0.42

Basic net income available per common share is computed using net income and the weighted average number of common shares outstanding during the period. Diluted net income per common share is computed using net income and the weighted average number of common shares outstanding, assuming dilution, which includes potentially dilutive common shares outstanding during the period. Potentially dilutive common shares include the assumed exercise of stock options and assumed vesting of restricted stock units using the treasury stock method. During the three and six months ended September 30, 2011, there were outstanding weighted average options to purchase 606,173 and 738,137 shares, respectively, that were not included in the computation of diluted net income per share since the exercise prices of the options exceeded the market price of the common stock. During the three and six months ended September 30, 2010, there were outstanding weighted average options to purchase 2,863,335 and 2,696,062 shares, respectively, that were not included in the computation of diluted net income per share since the exercise prices of the options exceeded the market price of the common stock. These options could dilute earnings per share in future periods if the market price of the common stock increases.