Loss Per Share - Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2018	Mar. 31, 2018	Jun. 30, 2019	Jun. 30, 2018
Earnings Per Share [Abstract]
Net income (loss)	$ 11,743	$ (3,666)	$ (2,894)	$ (2,901)	$ 8,077	$ (5,795)
Less: Dividend paid in-kind to preferred stockholders	(86)		(83)		(171)	(165)
Less: Deemed dividend on preferred stock	(145)		(126)		(285)	(247)
Net income (loss) attributable to common stockholders	11,512		(3,103)		7,621	(6,207)
Income (loss) per share - basic:
Numerator for basic income (loss) per share	$ 11,512		$ (3,103)		$ 7,621	$ (6,207)
Denominator for basic income (loss) per share (shares)	9,758,332		6,376,048		9,758,332	6,026,454
Basic income (loss) per common share (usd per share)	$ 1.18		$ (0.49)		$ 0.78	$ (1.03)
Income (loss) per share - diluted:
Numerator for basic income (loss) per share	$ 11,512		$ (3,103)		$ 7,621	$ (6,207)
Adjust: Interest and derivative revaluation expense related to convertible notes	1,338		0		0	0
Adjust: Paid in kind dividend on preferred shares	86		0		171	0
Adjust: Deemed dividend on preferred shares	145		0		285	0
Net income (loss) attributable to common stockholders - diluted	$ 13,081		$ (3,103)		$ 8,077	$ (6,207)
Denominator for basic income (loss) per share (shares)	9,758,332		6,376,048		9,758,332	6,026,454
Plus: Incremental shares underlying dilutive “in the money” stock options outstanding (shares)	25,257		0		11,483	0
Plus: Incremental common shares underlying convertible notes and related accrued interest (shares)	1,169,714		0		0	0
Plus: Incremental common shares underlying preferred stock (shares)	744,088		0		740,066	0
Denominator for diluted income (loss) per share (shares)	11,697,391		6,376,048		10,509,881	6,026,454
Diluted net income (loss) per common share (usd per share)	$ 1.12		$ (0.49)		$ 0.77	$ (1.03)