Exhibit 12.1

Computation of Ratio of Earnings to Combined Fixed Charges and Preferred Stock Dividends

	Year Ended December 31,															Nine Months Ended September 30, 2014
	2009			2010			2011			2012			2013
	(in thousands)
Computation of earnings:
Net income (loss) before provision for income taxes	$	(45,889	)	$	(73,554	)	$	(83,912	)	$	(47,381	)	$	(80,856	)	$	29,153
Fixed charges, as calculated below		9,305			10,179			7,776			10,437			6,751			3,105
Total earnings	$	(36,584	)	$	(63,375	)	$	(76,136	)	$	(36,944	)	$	(74,105	)		32,258
Computation of fixed charges:
Interest expense, including amortization of debt issuance cost		9,188			10,013			7,644			10,313			6,610			2,999
Estimated interest expense portion of rental expense		117			166			132			124			141			106
Total fixed charges		9,305			10,179			7,776			10,437			6,751			3,105
Ratio of earnings to combined fixed charges and preferred stock dividends(1)		—			—			—			—			—			10.4

(1) Our earnings were inadequate to cover combined fixed charges and preferred stock dividends for the years ended December 31, 2009, 2010, 2011, 2012, and 2013 by $45.9 million, $73.6 million, $83.9 million, $47.4 million and $80.9 million, respectively.

For the periods indicated above, we had no outstanding shares of preferred stock with required dividend payments.