Consolidated Statements of Stockholders' Equity - 6 months ended Jun. 30, 2018 - USD ($) $ in Thousands	Common Stock Forward Treasury Stock	Common Stock Forward	Common Stock	Additional Paid-in-Capital	Accumulated Other Comprehensive Income	Treasury Stock	Accumulated Deficit	Total
Balance at Dec. 31, 2017			$ 2,291	$ 1,250,899	$ 2,194	$ (3,102)	$ (1,178,636)	$ 73,646
Balance (in shares) at Dec. 31, 2017			229,073,517			587,151		229,073,517
Increase (Decrease) in Stockholders' Equity
Net loss attributable to the Company							(45,703)	$ (45,703)
Other comprehensive loss					(350)			(350)
Stock based compensation			$ 2	4,323				4,325
Stock based compensation (in shares)			202,523
Stock dividend				26			(26)
Stock dividend (in shares)			13,273
Stock option exercises			$ 4	98		$ (35)		67
Stock option exercises (in shares)			366,412			17,606
Equity component of convertible senior notes, net of issuance costs and income tax benefit				31,837				31,837
Purchase of capped call				(16,000)				(16,000)
Purchase of common stock forward	$ (27,500)	$ (27,500)
Purchase of common stock forward ( in shares)	14,397,906	14,397,906
Exercise of warrants (in shares)			100
Provision for common stock warrants				5,806				5,806
Balance at Jun. 30, 2018			$ 2,297	$ 1,276,989	$ 1,844	$ (30,637)	$ (1,224,365)	$ 26,128
Balance (in shares) at Jun. 30, 2018			229,655,825			15,002,663		229,655,825