Condensed Consolidated Statements of Changes in Equity (Unaudited) - USD ($) $ in Thousands	Total	Series A Convertible Preferred Stock [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Accumulated Deficit [Member]	Treasury Stock [Member]	Noncontrolling Interests [Member]
Beginning balances at Dec. 31, 2018	$ 257,858	$ 394	$ 79	$ 449,343	$ (381)	$ (192,507)	$ (96)	$ 1,026
Beginning balances, shares at Dec. 31, 2018		39,442	79,008,243				29,990
Vesting of restricted stock units	1		$ 1
Vesting of restricted stock units, shares			614,132
Stock-based compensation	5,920			5,920
Issuance of common stock under employee stock	604			604
Issuance of common stock under employee stock purchase plan, shares			113,703
Common stock issued as payment for MPUs	502			502
Common stock issued as payment for MPUs, shares			60,885
Exercise of SARs, shares			3,032
Common stock repurchasedunder share repurchaseprogram	(7,875)		$ (2)	(7,536)			$ (337)
Common stock repurchased and retired under share repurchase program, Shares			(1,513,743)				68,286
Series A convertible preferredstock dividend		$ 12				(12)
Series A convertible preferred stock dividend, shares		1,182
Net income (loss)	(15,651)					(15,922)		271
Foreign currency translation adjustments	(779)				(751)			(28)
Ending balances at Sep. 30, 2019	240,580	$ 406	$ 78	448,833	(1,132)	(208,441)	$ (433)	1,269
Ending balances, shares at Sep. 30, 2019		40,624	78,286,252				98,276
Beginning balances at Jun. 30, 2019	251,103	$ 394	$ 80	454,587	(582)	(204,416)	$ (96)	1,136
Beginning balances, shares at Jun. 30, 2019		39,442	79,753,545				29,990
Vesting of restricted stock units, shares			46,450
Stock-based compensation	1,782			1,782
Common stock repurchasedunder share repurchaseprogram	(7,875)		$ (2)	(7,536)			$ (337)
Common stock repurchased and retired under share repurchase program, Shares			(1,513,743)				68,286
Series A convertible preferredstock dividend		$ 12				(12)
Series A convertible preferred stock dividend, shares		1,182
Net income (loss)	(3,869)					(4,013)		144
Foreign currency translation adjustments	(561)				(550)			(11)
Ending balances at Sep. 30, 2019	240,580	$ 406	$ 78	448,833	(1,132)	(208,441)	$ (433)	1,269
Ending balances, shares at Sep. 30, 2019		40,624	78,286,252				98,276
Beginning balances at Dec. 31, 2019	237,516	$ 406	$ 78	447,681	(1,013)	(210,942)		1,306
Beginning balances, shares at Dec. 31, 2019		40,624	78,062,451
Vesting of restricted stock units	1		$ 1
Vesting of restricted stock units, shares			539,610
Stock-based compensation	4,818			4,818
Issuance of common stock under employee stock	430			430
Issuance of common stock under employee stock purchase plan, shares			166,580
Exercise of SARs, shares			41,091
Common stock repurchasedunder share repurchaseprogram	$ (2,527)		$ (1)	(2,526)
Common stock repurchased and retired under share repurchase program, Shares	(836,904)		(836,904)
Net income (loss)	$ (19,021)					(19,170)		149
Foreign currency translation adjustments	1,012				1,008			4
Ending balances at Sep. 30, 2020	222,229	$ 406	$ 78	450,403	(5)	(230,112)		1,459
Ending balances, shares at Sep. 30, 2020		40,624	77,972,828
Beginning balances at Jun. 30, 2020	225,573	$ 406	$ 78	448,908	(676)	(224,587)		1,444
Beginning balances, shares at Jun. 30, 2020		40,624	77,952,878
Vesting of restricted stock units, shares			19,950
Stock-based compensation	1,495			1,495
Net income (loss)	(5,543)					(5,525)		(18)
Foreign currency translation adjustments	704				671			33
Ending balances at Sep. 30, 2020	$ 222,229	$ 406	$ 78	$ 450,403	$ (5)	$ (230,112)		$ 1,459
Ending balances, shares at Sep. 30, 2020		40,624	77,972,828