CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' (DEFICIT) EQUITY (Unaudited) - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Treasury Stock	Accumulated Deficit	Accumulated Items of Other Comprehensive Loss	Non-Controlling Interest
Balance (in shares) at Dec. 31, 2017		20,804,000
Balance at Dec. 31, 2017	$ (1,032)	$ 21	$ 1,327,084	$ (7,159)	$ (1,323,723)	$ (1,324)	$ 4,069
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(14,261)				(14,261)
Net income attributable to non-controlling interest					(27)		27
Foreign currency translation	61					61
Movement in non-controlling interest	(990)						(990)
Common stock issuance (in shares)		343,000
Employee taxes paid on withholding shares (in shares)		(20,000)
Employee taxes paid on withholding shares	(270)			(270)
Stock-based compensation	869		869
Proceeds from exercise of stock options, net (in shares)		4,000
Proceeds from exercise of stock options, net	32		32
Balance (in shares) at Mar. 31, 2018		21,131,000
Balance at Mar. 31, 2018	8,594	$ 21	1,327,985	(7,429)	(1,313,826)	(1,263)	3,106
Balance (in shares) at Dec. 31, 2017		20,804,000
Balance at Dec. 31, 2017	(1,032)	$ 21	1,327,084	(7,159)	(1,323,723)	(1,324)	4,069
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(43,971)
Net income attributable to non-controlling interest	75
Foreign currency translation	24
Balance (in shares) at Sep. 30, 2018		21,302,000
Balance at Sep. 30, 2018	(19,923)	$ 21	1,330,751	(7,645)	(1,344,566)	(1,300)	2,816
Balance (in shares) at Mar. 31, 2018		21,131,000
Balance at Mar. 31, 2018	8,594	$ 21	1,327,985	(7,429)	(1,313,826)	(1,263)	3,106
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(14,256)				(14,256)
Net income attributable to non-controlling interest					(23)		23
Foreign currency translation	61					61
Movement in non-controlling interest	(205)						(205)
Common stock issuance (in shares)		104,000
Employee taxes paid on withholding shares (in shares)		(16,000)
Employee taxes paid on withholding shares	(201)			(201)
Stock-based compensation	1,382		1,382
Proceeds from exercise of stock options, net	1		1
Balance (in shares) at Jun. 30, 2018		21,219,000
Balance at Jun. 30, 2018	(5,605)	$ 21	1,329,368	(7,630)	(1,329,086)	(1,202)	2,924
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(15,454)				(15,454)
Net income attributable to non-controlling interest	25				(25)		25
Foreign currency translation	(98)					(98)
Movement in non-controlling interest	(133)						(133)
Common stock issuance (in shares)		82,000
Employee taxes paid on withholding shares (in shares)		(1,000)
Employee taxes paid on withholding shares	(15)			(15)
Stock-based compensation	1,320		1,320
Proceeds from exercise of stock options, net (in shares)		2,000
Proceeds from exercise of stock options, net	63		63
Balance (in shares) at Sep. 30, 2018		21,302,000
Balance at Sep. 30, 2018	$ (19,923)	$ 21	1,330,751	(7,645)	(1,344,566)	(1,300)	2,816
Balance (in shares) at Dec. 31, 2018	25,455,000	25,455,000
Balance at Dec. 31, 2018	$ 57	$ 25	1,368,968	(7,646)	(1,363,019)	(1,065)	2,794
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(19,622)				(19,622)
Net income attributable to non-controlling interest					(22)		22
Foreign currency translation	197					197
Movement in non-controlling interest	(1,133)						(1,133)
Common stock issuance (in shares)		1,339,000
Common stock issuance, net	(41)	$ 2
Common stock issuance, net			(43)
Employee taxes paid on withholding shares (in shares)		(48,000)
Employee taxes paid on withholding shares	(268)			(268)
Stock-based compensation	890		890
Balance (in shares) at Mar. 31, 2019		26,746,000
Balance at Mar. 31, 2019	$ (19,972)	$ 27	1,369,815	(7,914)	(1,382,715)	(868)	1,683
Balance (in shares) at Dec. 31, 2018	25,455,000	25,455,000
Balance at Dec. 31, 2018	$ 57	$ 25	1,368,968	(7,646)	(1,363,019)	(1,065)	2,794
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(62,006)
Net income attributable to non-controlling interest	63
Foreign currency translation	$ 152
Balance (in shares) at Sep. 30, 2019	26,486,000	26,486,000
Balance at Sep. 30, 2019	$ (60,212)	$ 26	1,372,016	(7,958)	(1,425,140)	(913)	1,757
Balance (in shares) at Mar. 31, 2019		26,746,000
Balance at Mar. 31, 2019	(19,972)	$ 27	1,369,815	(7,914)	(1,382,715)	(868)	1,683
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(18,535)				(18,535)
Net income attributable to non-controlling interest					(20)		20
Foreign currency translation	(27)					(27)
Movement in non-controlling interest	23						23
Common stock issuance (in shares)		33,000
Employee taxes paid on withholding shares (in shares)		(9,000)
Employee taxes paid on withholding shares	(42)			(42)
Stock-based compensation	1,020		1,020
Balance (in shares) at Jun. 30, 2019		26,770,000
Balance at Jun. 30, 2019	(37,533)	$ 27	1,370,835	(7,956)	(1,401,270)	(895)	1,726
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(23,849)				(23,849)
Net income attributable to non-controlling interest	21				(21)		21
Foreign currency translation	(18)					(18)
Movement in non-controlling interest	10						10
Common stock issuance (in shares)		(283,000)
Common stock issuance, net	(1)	$ (1)
Employee taxes paid on withholding shares (in shares)		(1,000)
Employee taxes paid on withholding shares	(2)			(2)
Stock-based compensation	$ 1,181		1,181
Balance (in shares) at Sep. 30, 2019	26,486,000	26,486,000
Balance at Sep. 30, 2019	$ (60,212)	$ 26	$ 1,372,016	$ (7,958)	$ (1,425,140)	$ (913)	$ 1,757