Consolidated Statements of Stockholders' Equity - USD ($) shares in Thousands, $ in Thousands	Total	Preferred Stock	Common Stock	Additional Paid-in Capital	Accumulated Deficit	Accumulated Other Comprehensive Income (Loss)	Noncontrolling Interests	Series E Preferred Stock	Series E Preferred Stock Preferred Stock	Series E Preferred Stock Additional Paid-in Capital
Beginning Balance at Dec. 31, 2017	$ (45,615)	$ 0	$ 59	$ 519,531	$ (569,759)	$ 4,604	$ (50)
Beginning Balance, shares (in shares) at Dec. 31, 2017		0	58,645
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(8,143)				(8,058)		(85)
Foreign currency translation adjustment	(9,481)					(9,481)
Exercise of stock options, vesting of restricted stock units and stock issued under employee stock purchase plan	2,408		$ 3	2,405
Exercise of stock options, vesting of restricted stock units and stock issued under ESPP (in shares)			2,645
Taxes withheld on net settled vesting of restricted stock units	(656)			(656)
Issuance of common stock	20,086		$ 12	20,074
Issuance of common stock (in shares)			12,690
Share-based compensation	4,876			4,876
Share-based compensation (in shares)			0
Ending Balance at Dec. 31, 2018	(36,525)	$ 0	$ 74	546,230	(577,817)	(4,877)	(135)
Ending Balance, shares (in shares) at Dec. 31, 2018		0	73,980
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(40,110)				(40,125)		15
Foreign currency translation adjustment	998					998
Exercise of stock options, vesting of restricted stock units and stock issued under employee stock purchase plan	3,265		$ 2	3,263
Exercise of stock options, vesting of restricted stock units and stock issued under ESPP (in shares)			2,254
Taxes withheld on net settled vesting of restricted stock units	(1,269)			(1,269)
Issuance of common stock	1,439			1,439				$ 10,000		$ 10,000
Issuance of common stock (in shares)			263						10
Exercise of warrants			5,477
Exercise of warrants	17,542		$ 6	17,536
Share-based compensation	7,302			7,302
Series E preferred stock dividends	0			361	(361)
Ending Balance at Dec. 31, 2019	$ (37,358)	$ 0	$ 82	$ 584,862	$ (618,303)	$ (3,879)	$ (120)
Ending Balance, shares (in shares) at Dec. 31, 2019		10	81,974