Three Months Ended September 30,

Nine Months Ended September 30,

2011

2010

2011

2010

Numerator:

Net income (loss)

$

5,361

$

1,182

$

32,255

$

(1,386

)

Denominator:

Weighted average common stock outstanding (basic)

41,396,431

40,404,126

41,146,197

40,246,374

Common equivalent shares from options to purchase common stock, restricted common stock units and performance stock units

1,100,936

950,554

1,220,664

—

Weighted average common stock outstanding (diluted)

42,497,367

41,354,680

42,366,861

40,246,374

Basic net income (loss) per share

$

0.13

$

0.03

$

0.78

$

(0.03

)

Diluted net income (loss) per share

$

0.13

$

0.03

$

0.76

$

(0.03

)