Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2019		Dec. 31, 2018
Stockholders' equity
Preferred stock, par value	$ 0.001		$ 0.001
Preferred stock, shares authorized	25,000,000		25,000,000
Preferred stock, shares issued	0		0
Preferred stock, shares outstanding	0		0
Common stock, par value	$ 0.001		$ 0.001
Common stock, shares authorized	750,000,000
Common stock, shares issued	508,065,495		462,355,725
Treasury stock, shares	1,652,771		1,941,749
Debt Instrument [Line Items]
Future interest payable - current	$ 102,294	[1]	$ 105,125
Future interest payable - long-term	2,232,570		2,664,211
Future interest payable on senior secured notes
Debt Instrument [Line Items]
Future interest payable - current	86,054		85,303
Future interest payable - long-term	$ 78,860		$ 164,914

[1] Our current maturities of long-term debt as of December 31, 2019 include $86.1 million of future interest payable related to the 2021 Senior Secured Notes and 2022 Senior Secured Notes that is due within the next twelve months.