Three Months Ended June 30,

Six Months Ended June 30,

2012

2011

2012

2011

(unaudited, in thousands, except per share amounts)

Numerator:

Net loss available to common stockholders

$

(6,825

)

$

(7,847

)

$

(16,507

)

$

(15,600

)

Denominator:

Weighted average shares outstanding—basic

36,045

35,775

35,818

35,520

Potential common shares—options (treasury stock method)

—

Weighted average shares outstanding—diluted

36,045

35,775

35,818

35,520

Shares excluded (anti-dilutive)

18

209

25

348

Shares excluded due to an exercise price greater than weighted average stock price for the period

1,483

1,970

1,364

1,848

Net loss per common share:

Basic

($

0.19

)

($

0.22

)

($

0.46

)

($

0.44

)

Diluted

($

0.19

)

($

0.22

)

($

0.46

)

($

0.44

)