Condensed Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Common Stock 3.75% Convertible Senior Notes	Common Stock 5.5% Convertible Senior Notes	Common Stock Private placement	Common Stock	Additional Paid-in-Capital 3.75% Convertible Senior Notes	Additional Paid-in-Capital 5.5% Convertible Senior Notes	Additional Paid-in-Capital Private placement	Additional Paid-in-Capital	Accumulated Other Comprehensive Income	Treasury Stock	Accumulated Deficit	3.75% Convertible Senior Notes	5.5% Convertible Senior Notes	Private placement	Total
Balance at Dec. 31, 2019				$ 3,186				$ 1,506,953	$ 1,288	$ (31,216)	$ (1,350,307)				$ 129,904
Balance (in shares) at Dec. 31, 2019				318,637,560						15,259,045
Increase (Decrease) in Stockholders' Equity
Net loss attributable to the Company											(46,833)				(46,833)
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								20			(20)
Stock dividend (in shares)				5,156
Issuance of 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 convertible senior notes, net of issuance costs and income tax (benefit) expense								115,952							115,952
Purchase of capped calls								(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 5.5% Convertible Senior Notes, net of income tax benefit				$ 94				(52,855)							(52,761)
Repurchase of 5.5% Convertible Senior Notes, net of income tax benefit (in shares)				9,409,591
Shares issued for acquisitions				$ 97				49,576							49,673
Shares issued for acquisitions (in shares)				9,658,465
Balance at Jun. 30, 2020				$ 3,482				1,658,438	1,159	$ (31,359)	(1,397,160)				234,560
Balance (in shares) at Jun. 30, 2020				348,201,792						15,292,591
Balance (ASU 2020-06) at Dec. 31, 2020								(130,185)			9,549				(120,636)
Balance at Dec. 31, 2020				$ 4,740				3,446,650	2,451	$ (40,434)	(1,946,488)				$ 1,466,919
Balance (in shares) at Dec. 31, 2020				473,977,469						15,926,068					473,977,469
Increase (Decrease) in Stockholders' Equity
Net loss attributable to the Company											(160,380)				$ (160,380)
Other comprehensive loss									(2,417)						(2,417)
Stock-based compensation								20,815							20,815
Stock-based compensation (in shares)				15,166
Issuance of common stock, net			$ 549	$ 322			$ 1,564,088	2,022,866						$ 1,564,637	2,023,188
Issuance of common stock, net (in shares)			54,966,188	32,200,000
Stock option exercises				$ 18				4,687							4,705
Stock option exercises (in shares)				1,760,450
Exercise of warrants				$ 208				15,242							15,450
Exercise of warrants (in shares)				20,843,108
Provision for common stock warrants								3,243							3,243
Conversion of Convertible Senior Notes	$ 30	$ 1			$ 15,155	$ 159						$ 15,185	$ 160
Conversion of Convertible Senior Notes (in shares)	3,016,036	69,808
Balance at Jun. 30, 2021				$ 5,868				$ 6,962,720	$ 34	$ (40,434)	$ (2,097,319)				$ 4,830,869
Balance (in shares) at Jun. 30, 2021				586,848,225						15,926,068					586,848,225