EXHIBIT 12.1

STATEMENT REGARDING COMPUTATION OF RATIOS

(in thousands)

	Year Ended December 31,															Nine Months Ended September 30,
	2012			2013			2014			2015			2016			2017
Earnings:
Pretax loss	$	(4,406	)	$	(36,445	)	$	(59,312	)	$	(117,372	)	$	(76,390	)	$	(51,746	)
Add fixed charges		828			1,460			883			482			40 7			2 40
Total earnings		(3,578	)		(34,985	)		(58,429	)		(116,890	)		(75,98 3	)		(51,5 06	)
Fixed charges:
Interest expensed, including amortization of debt discount and deferred financing costs		676			1,344			776			222			-			-
Estimated interest component of rent expense		152			116			108			259			40 7			2 40
Total fixed charges		828			1,460			883			482			40 7			2 40
Ratio of earnings to fixed charges		N/A			N/A			N/A			N/A			N/A			N/A
Deficiency of earnings available to cover fixed charges	$	(4,406	)	$	(36,445	)	$	(59,312	)	$	(117,372	)	$	(76,390	)	$	(51,746	)