Exhibit 12.1

	Three Months Ended March 31,			Year Ended December 31,
	2013			2012			2011			2010			2009			2008
(dollars in thousands)
Loss:
Loss from continuing operations	$	(12,886	)	$	(60,712	)	$	(48,214	)	$	(40,112	)	$	(19,885	)	$	(14,542	)
Add: Fixed charges		3,310			9,142			4,012			2,516			1,232			1,540
Less: Capitalized interest		(20	)		(1,332	)		(297	)		—			—			—
Total loss	$	(9,596	)	$	(52,902	)	$	(44,499	)	$	(37,596	)	$	(18,653	)	$	(13,002	)
Fixed Charges:
Interest expense	$	1,357		$	5,464		$	2,649		$	1,612		$	868		$	283
Amortization and expensing of debt expense		1,898			2,206			928			762			235			1,102
Interest component of rent expense		35			140			138			142			129			155
Capitalized interest		20			1,332			297			—			—			—
Total fixed charges	$	3,310		$	9,142		$	4,012		$	2,516		$	1,232		$	1,540
Ratio of Earnings to Fixed Charges		—			—			—			—			—			—
Deficiency of Earnings Available to Cover Fixed Charges	$	(12,906	)	$	(62,044	)	$	(48,511	)	$	(40,112	)	$	(19,885	)	$	(14,542	)