Exhibit 12.1

COMPUTATION OF RATIO OF EARNINGS TO FIXED CHARGES

(in thousands)

	For the Year Ended December 31,															Nine-Months Ended September 30,
	2003			2004			2005			2006			2007			2007			2008
Earnings (loss)-
Loss before income taxes	$	(29,388	)	$	(93,479	)	$	(88,628	)	$	(78,298	)	$	(29,469	)	$	(15,182	)	$	(53,229	)
Add fixed Charges:
Interest expense on indebtedness	$	990		$	4,480		$	6,556		$	10,256		$	18,581			12,317			13,780
Estimated interest on rental expense		300			1,611			1,948			1,959			1,733			1,341			1,300
Amortization of deferred closing costs related to convertible notes		156			521			816			827			1,324			936			1,166
Amortization of discount on convertible notes		271			—			—			—			7,649			5,017			9,317
Total Adjusted Loss	$	(27,621	)	$	(86,867	)	$	(79,273	)	$	(65,256	)	$	(182	)	$	4,429		$	(27,666	)
Fixed Charges-
Interest expense on indebtedness	$	990		$	4,480		$	6,556		$	10,256		$	28,205			12,317			13,780
Estimated interest on rental expense		300			1,611			1,948			1,959			1,733			1,341			1,300
Amortization of deferred closing costs related to convertible notes		156			521			816			827			1,324			936			1,166
Amortization of discount on convertible notes		271			—			—			—			7,649			5,012			9,317
Total Fixed Charges	$	1,717		$	6,612		$	9,320		$	13,042		$	29,287		$	19,611		$	25,563
Coverage deficiency	$	(29,388	)	$	(93,479	)	$	(88,628	)	$	(78,298	)	$	(29,469	)	$	(15,182	)	$	(53,229	)
Ratio of earnings to fixed charges