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
Increase (decrease) in equity
Adoption of ASU						$ (40)	$ 40
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
Deemed dividends - accretion of beneficial conversion feature - temporary equity	$ 0
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
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 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