NOTE 3. NET INCOME (LOSS) PER COMMON SHARE

Basic net income (loss) per share is calculated by dividing the net income (loss) by the weighted-average number of shares of common stock outstanding during the period. Diluted net loss per share is calculated by dividing the net income (loss) by the weighted-average number of shares of common stock outstanding during the period, plus dilutive common shares for the period determined using the treasury-stock method. For purposes of this calculation, options to purchase stock are considered to be potential common shares and are only included in the calculation of diluted net income (loss) per share when their effect is dilutive. Basic and diluted earnings per share are calculated as follows:

(in thousands, except for per share amounts)	Three Months Ended June 30,				Six Months Ended June 30,
	2011		2010		2011		2010
Numerator:
Net income (loss)	$	(5,679)	$	4,126	$	93,138	$	297

Denominator for basic net income (loss) per share	54,056		52,437		53,707		52,368
Net effect of dilutive common stock equivalents	—		667		2,176		550
Denominator for diluted net income (loss) per share:	54,056		53,104		55,883		52,918


Basic net income (loss) per share	$	(0.11)	$	0.08	$	1.73	$	0.01
Diluted net income (loss) per share	$	(0.11)	$	0.08	$	1.67	$	0.01

For the three and six months ended June 30, 2011, the total number of antidilutive outstanding common stock equivalents excluded from the net income per share computation was 4.0 million and 0.8 million, respectively. For the three and six months ended June 30, 2010, 3.2 million and 3.7 million common stock equivalents, respectively, were not included in dilutive shares because their effect is anti-dilutive.