Exhibit 12.1

COMPUTATION OF RATIO OF EARNINGS TO COMBINED FIXED CHARAGES AND PREFERRED STOCK DIVIDENDS

	Three Months Ended March 31,						Year Ended December 31,
	2015			2014			2014			2013			2012			2011			2010
	(in thousands)
Earnings:
Income (loss) before income taxes	$	(6,197	)	$	(2,471	)	$	(18,148	)	$	17,227		$	25,878		$	(31,887	)	$	(5,686	)
Fixed charges, as calculated below		518			280			2,035			1,395			1,436			1,404			1,733
Amortization of capitalized interest		135			132			530			474			455			430			404
Less: Capitalized interest		(103	)		(46	)		(1,209	)		(146	)		(300	)		(299	)		(322	)
Total earnings	$	(5,647	)	$	(2,105	)	$	(16,792	)	$	18,950		$	27,469		$	(30,352	)	$	(3,871	)
Computation of fixed charges:
Interest expense		341			180			609			958			784			584			810
Capitalized interest		103			46			1,209			146			300			299			322
Interest component of rent expense(1)		74			54			217			291			352			521			601
Total fixed charges	$	518		$	280		$	2,035		$	1,395		$	1,436		$	1,404		$	1,733
Ratio of earnings to combined fixed charges and preferred stock dividends(2)		N/A			N/A			N/A			13.58			19.13			N/A			N/A
Deficiency of earnings to combined fixed charges and preferred stock dividends(3)	$	(6,165	)	$	(2,385	)	$	(18,827	)		—			—		$	(31,756	)	$	(5,604	)

(1) Represents the portion of rental expense from operating leases that is estimated by us to be representative of interest.

(2) For periods in which there is a deficiency of earnings available to cover combined fixed charges and preferred stock dividends, the ratio information is not applicable.

(3) We have not paid any dividends on preferred stock and no preferred stock was outstanding for any of the periods presented