Condensed Consolidated Statements of Stockholders' (Deficit) Equity - USD ($) $ in Thousands	Common Stock	Additional Paid-in-Capital	Accumulated Other Comprehensive Income	Treasury Stock	Accumulated Deficit	Total
Balance at Dec. 31, 2018	$ 2,342	$ 1,289,714	$ 1,584	$ (30,637)	$ (1,260,290)	$ 2,713
Balance (in shares) at Dec. 31, 2018	234,160,661			15,002,663
Increase (Decrease) in Stockholders' Equity
Net loss attributable to the Company					(49,046)	(49,046)
Other comprehensive loss			(124)			(124)
Stock-based compensation	$ 8	5,115				5,123
Stock-based compensation (in shares)	780,985
Stock dividend		26			(26)
Stock dividend (in shares)	10,147
Public offerings, common stock, net	$ 119	28,146				28,265
Public offerings, common stock, net (in shares)	11,881,637
Stock option exercises	$ 1	248		$ (44)		205
Stock option exercises (in shares)	141,743			17,774
Provision for common stock warrants		5,662				5,662
Balance at Jun. 30, 2019	$ 2,470	1,328,911	1,460	$ (30,681)	(1,309,362)	(7,202)
Balance (in shares) at Jun. 30, 2019	246,975,173			15,020,437
Balance at Dec. 31, 2019	$ 3,186	1,507,116	1,400	$ (31,216)	(1,345,807)	$ 134,679
Balance (in shares) at Dec. 31, 2019	318,637,560			15,259,045		318,637,560
Increase (Decrease) in Stockholders' Equity
Net loss attributable to the Company					(46,135)	$ (46,135)
Other comprehensive loss			(129)			(129)
Stock-based compensation	$ 6	6,325		$ (143)		6,188
Stock-based compensation (in shares)	586,558			33,371
Stock dividend		19			(19)
Stock dividend (in shares)	5,156
Public offerings, common stock, net		(269)				(269)
Stock option exercises	$ 69	15,729				15,798
Stock option exercises (in shares)	6,905,936			175
Equity component of $200M convertible senior notes issued, net of issuance costs and income tax benefit		115,884				115,884
Purchase of capped call		(16,253)				(16,253)
Termination of capped calls		24,158				24,158
Provision for common stock warrants		7,983				7,983
Accretion of discount, preferred stock		(29)				(29)
Conversion of preferred stock	$ 30	1,148				1,178
Conversion of preferred stock (in shares)	2,998,526
Repurchase of $100 million convertible senior notes, net of income tax benefit	$ 94	(52,855)				(52,761)
Repurchase of $100 million convertible senior notes, net of income tax benefit (In shares)	9,409,591
Shares issued for acquisition	$ 97	49,576				49,673
Shares issued for acquisition (in shares)	9,658,465
Balance at Jun. 30, 2020	$ 3,482	$ 1,658,532	$ 1,271	$ (31,359)	$ (1,391,961)	$ 239,965
Balance (in shares) at Jun. 30, 2020	348,201,792			15,292,591		348,201,792