Exhibit 12.1

Computation of Deficiency in the Coverage of Fixed Charges by Earnings Before Fixed Charges and

Preferred Stock Dividends

	Year ended December 31,															Nine months ended September 30,
	2009			2010			2011			2012			2013			2014
	(in thousands)
Fixed charges:
Interest expense	$	97		$	94		$	90		$	86		$	82		$	89
Estimate of interest expense within rental expense		153			204			220			104			84			202
Total fixed charges	$	250		$	298		$	310		$	190		$	166		$	291
Earnings before fixed charges:
Net loss before provision for income taxes	$	(25,159	)	$	(32,177	)	$	(2,318	)	$	(121,287	)	$	(111,985	)	$	(91,373	)
Add fixed charges		250			298			310			190			166			291
Total earnings (loss) before fixed charges	$	(24,909	)	$	(31,879	)	$	(2,008	)	$	(121,097	)	$	(111,819	)	$	(91,082	)
Deficiency of earnings to cover fixed charges:	$	(25,159	)	$	(32,177	)	$	(2,318	)	$	(121,287	)	$	(111,985	)	$	(91,373	)
Earnings before fixed charges and preferred stock dividends:
Net loss before provision for income taxes	$	(25,159	)	$	(32,177	)	$	(2,318	)	$	(121,287	)	$	(111,985	)	$	(91,373	)
Add fixed charges		250			298			310			190			166			291
Add preferred stock dividends		—			—			—			—			—			—
Total earnings (loss) before fixed charges and preferred stock dividends	$	(24,909	)	$	(31,879	)	$	(2,008	)	$	(121,097	)	$	(111,819	)	$	(91,082	)
Deficiency of earnings to cover fixed charges and preferred stock dividends:	$	(25,159	)	$	(32,177	)	$	(2,318	)	$	(121,287	)	$	(111,985	)	$	(91,373	)