Consolidated Statement of Stockholders Equity, Series A and Series B Convertible Preferred Stock - USD ($) shares in Thousands, $ in Thousands	Series A convertible preferred stock	Series B convertible preferred stock	Common Stock	Treasury Stock	Additional Paid-in Capital	Accumulated Deficit	Accumulated Other Comprehensive Loss	Total
Balance at the beginning of the period at Dec. 31, 2017			$ 11		$ 158,738	$ (55,617)	$ (40)	$ 103,092
Balance at the beginning of the period (in shares) at Dec. 31, 2017			106,275
Increase (decrease) in equity
Share-based compensation					12,440			12,440
Restricted stock vesting (in shares)			123
Net loss						(16,200)		(16,200)
Balance at the end of the period at Mar. 31, 2018			$ 11		171,178	(71,857)		99,332
Balance at the end of the period (in shares) at Mar. 31, 2018			106,398
Balance at the beginning of the period at Dec. 31, 2017			$ 11		158,738	(55,617)	(40)	103,092
Balance at the beginning of the period (in shares) at Dec. 31, 2017			106,275
Increase (decrease) in equity
Deemed dividends - accretion of beneficial conversion feature - temporary equity	$ 0
Net loss								(19,682)
Balance at the end of the period at Jun. 30, 2018			$ 11		169,454	(75,339)		94,126
Balance at the end of the period (in shares) at Jun. 30, 2018			106,398
Increase (decrease) in equity
Adoption of ASU						(40)	$ 40
Balance at the beginning of the period at Mar. 31, 2018			$ 11		171,178	(71,857)		99,332
Balance at the beginning of the period (in shares) at Mar. 31, 2018			106,398
Increase (decrease) in equity
Share-based compensation					(1,724)			(1,724)
Deemed dividends - accretion of beneficial conversion feature - temporary equity	0
Net loss						(3,482)		(3,482)
Balance at the end of the period at Jun. 30, 2018			$ 11		169,454	(75,339)		94,126
Balance at the end of the period (in shares) at Jun. 30, 2018			106,398
Balance at the beginning of the period at Dec. 31, 2018			$ 11	$ (35)	180,862	(97,617)		83,221
Balance at the beginning of the period (in shares) at Dec. 31, 2018			106,856	6
Balance at the beginning of the period at Dec. 31, 2018	40,091	$ 26,159
Increase (decrease) in equity
Share-based compensation					5,884			5,884
Restricted stock vesting					495			495
Restricted stock vesting (in shares)			180
Shares repurchased related to share-based compensation				$ (260)				(260)
Shares repurchased related to share-based compensation (in shares)			(65)	(65)
Preferred stock dividends					(4,972)			(4,972)
Preferred stock dividends	3,133	1,819
Deemed dividends - accretion of beneficial conversion feature					(551)			(551)
Deemed dividends - accretion of beneficial conversion feature - temporary equity	551
Net loss						(12,043)		(12,043)
Balance at the end of the period at Mar. 31, 2019			$ 11	$ (295)	183,834	(109,873)		73,677
Balance at the end of the period (in shares) at Mar. 31, 2019			106,971	71
Balance at the end of the period at Mar. 31, 2019	43,775	27,978
Balance at the beginning of the period at Dec. 31, 2018			$ 11	$ (35)	180,862	(97,617)		83,221
Balance at the beginning of the period (in shares) at Dec. 31, 2018			106,856	6
Balance at the beginning of the period at Dec. 31, 2018	40,091	26,159
Increase (decrease) in equity
Preferred stock dividends								(4,972)
Deemed dividends - accretion of beneficial conversion feature - temporary equity	1,000
Net loss								(18,762)
Balance at the end of the period at Jun. 30, 2019			$ 11	$ (466)	170,374	(116,592)		53,327
Balance at the end of the period (in shares) at Jun. 30, 2019			107,169	103
Balance at the end of the period at Jun. 30, 2019	44,263	46,987
Increase (decrease) in equity
Adoption of ASU | Accounting Standards Update 2016-02						(213)		(213)
Adoption of ASU | Accounting Standards Update 2018-07					2,116			2,116
Balance at the beginning of the period at Mar. 31, 2019			$ 11	$ (295)	183,834	(109,873)		73,677
Balance at the beginning of the period (in shares) at Mar. 31, 2019			106,971	71
Balance at the beginning of the period at Mar. 31, 2019	43,775	27,978
Increase (decrease) in equity
Share-based compensation					(12,972)			(12,972)
Restricted stock vesting (in shares)			230
Shares repurchased related to share-based compensation				$ (171)				(171)
Shares repurchased related to share-based compensation (in shares)			(32)	32
Preferred stock dividends		19,009
Deemed dividends - accretion of beneficial conversion feature					(488)			(488)
Deemed dividends - accretion of beneficial conversion feature - temporary equity	488
Net loss						(6,719)		(6,719)
Balance at the end of the period at Jun. 30, 2019			$ 11	$ (466)	$ 170,374	$ (116,592)		$ 53,327
Balance at the end of the period (in shares) at Jun. 30, 2019			107,169	103
Balance at the end of the period at Jun. 30, 2019	$ 44,263	$ 46,987