Earnings (Loss) Per Share - Schedule of Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Numerator
Net income (loss), basic	$ (17,528)	$ 15,533	$ (48,523)	$ 3,554
Add: Interest on 2033 Senior Notes	652	604	1,291	1,196
Change in FV of embedded derivative income	(5,069)	(4,872)	(10,014)	(4,734)
Net income (loss), diluted	$ (21,945)	$ 11,265	$ (57,246)	$ 16
Denominator
Weighted average common shares outstanding, basic (in shares)	559,347,540	547,558,800	558,892,375	546,691,117
Effect of dilutive securities:
Stock options (in shares)	0	4,264,000	0	4,222,000
Warrants (in shares)	0	661,000	0	1,267,000
2033 Senior Notes (in shares)	4,816,000	4,556,000	4,725,000	4,556,000
Dilutive potential shares (in shares)	4,816,000	9,481,000	4,725,000	10,045,000
Weighted average common shares outstanding, diluted (in shares)	564,163,808	557,040,435	563,617,274	556,735,862
Earnings per share, basic (in dollars per share)	$ (0.03)	$ 0.03	$ (0.09)	$ 0.01
Earnings (loss) per share, diluted (in dollars per share)	$ (0.04)	$ 0.02	$ (0.10)	$ 0.00