Exhibit 12.1

COMPUTATION OF RATIO OF EARNINGS TO FIXED CHARGES

(in thousands)

	For the Year Ended December 31,															Six-Months Ended June 30,
	2003			2004			2005			2006			2007			2007		2008
Earnings (loss)-
Loss before income taxes	$	(29,388	)	$	(93,479	)	$	(88,628	)	$	(78,298	)	$	(29,469	)	$	4,530	$	(37,991	)
Add fixed Charges:
Interest expense on indebtedness	$	990		$	4,480		$	6,556		$	8,676		$	18,581			8,086		9,460
Estimated interest on rental expense		300			1,611			1,948			1,959			1,733			820		894
Amortization of deferred closing costs related to convertible notes		156			521			816			827			1,324			548		778
Amortization of discount on convertible notes		271			—			—			—			7,649			1,945		6,189
Total Adjusted Loss	$	(27,621	)	$	(86,867	)	$	(79,273	)	$	(66,836	)	$	(182	)	$	15,929	$	(20,670	)
Fixed Charges-
Interest expense on indebtedness	$	990		$	4,480		$	6,556		$	8,676		$	18,581			8,086		9,460
Estimated interest on rental expense		300			1,611			1,948			1,959			1,733			820		894
Amortization of deferred closing costs related to convertible notes		156			521			816			827			1,324			548		778
Amortization of discount on convertible notes		271			—			—			—			7,649			1,945		6,189
Total Fixed Charges	$	1,717		$	6,612		$	9,320		$	11,462		$	29,287		$	11,399	$	17,321
Coverage deficiency	$	(29,388	)	$	(93,479	)	$	(88,628	)	$	(78,298	)	$	(29,469	)	$	—	$	(37,991	)
Ratio of earnings to fixed charges																	1.4x