Exhibit 12.1

COMPUTATION OF RATIO OF EARNINGS TO FIXED CHARGES

(in thousands)

	For the Year Ended December 31,
	2004			2005			2006			2007			2008
Earnings (loss)-
Loss before income taxes	$	(93,479	)	$	(88,628	)	$	(78,298	)	$	(29,469	)	$	(64,335	)
Add fixed Charges:
Interest expense on indebtedness	$	4,480		$	6,556		$	10,256		$	18,581		$	17,686
Estimated interest on rental expense		1,611			1,948			1,959			1,733			1,848
Amortization of deferred closing costs related to convertible notes		521			816			827			1,324			1,416
Amortization of discount on convertible notes		—			—			—			7,649			11,290
Total Adjusted Loss	$	(86,867	)	$	(79,308	)	$	(65,256	)	$	(182	)	$	(32,095	)
Fixed Charges-
Interest expense on indebtedness	$	4,480		$	6,556		$	10,256		$	18,581		$	17,686
Estimated interest on rental expense		1,611			1,948			1,959			1,733			1,848
Amortization of deferred closing costs related to convertible notes		521			816			827			1,324			1,416
Amortization of discount on convertible notes		—			—			—			7,649			11,290
Total Fixed Charges	$	6,612		$	9,320		$	13,042		$	29,287		$	32,240
Coverage deficiency	$	(93,479	)	$	(88,628	)	$	(78,298	)	$	(29,469	)	$	(64,335	)