Earnings Per Share - Dilutive Potential Common Shares (Details) - USD ($) $ in Thousands	1 Months Ended				3 Months Ended			6 Months Ended
	Jan. 31, 2021	Nov. 30, 2020	Aug. 31, 2020	Sep. 30, 2019	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2020	Jun. 30, 2022	Jun. 30, 2021	Mar. 31, 2021	May 31, 2020	May 29, 2020	May 18, 2020	Mar. 31, 2018	Jul. 20, 2017	Apr. 04, 2017
Earnings Per Share
Number of dilutive potential common stock								148,988,846	138,366,461
Common stock shares issued		43,700,000	35,276,250
3.75% Convertible Senior Notes
Earnings Per Share
Principal amount					$ 197,278	$ 15,200		$ 197,278	$ 15,200		$ 212,500	$ 12,500	$ 200,000
Conversion of notes through common stock issuance					0	0		0	3,016,036
Interest rate (as a percent)					3.75%	3.75%		3.75%	3.75%		3.75%	3.75%	3.75%
7.5% Convertible Senior Note
Earnings Per Share
Principal amount				$ 40,000
Conversion of notes through common stock issuance				16,000,000.0
Interest rate (as a percent)				7.50%						7.50%
5.5% Convertible Senior Notes
Earnings Per Share
Principal amount	$ 200						$ 33,500							$ 100,000
Conversion of notes through common stock issuance	69,808						14,600,000
Repurchase amount											$ 66,300
Interest rate (as a percent)	5.50%						5.50%			5.50%	5.50%			5.50%
Warrants issued in July 2017
Earnings Per Share
Number of warrants exercised (in shares)								13,094,217	13,094,217
Warrants issued with the Amazon, Inc transaction agreement
Earnings Per Share
Shares of common stock that can be purchased from warrants issued (in shares)																55,286,696
Number of warrants exercised (in shares)								17,461,994	13,960,354
Warrants issued with the Walmart Stores, Inc transaction agreement
Earnings Per Share
Shares of common stock that can be purchased from warrants issued (in shares)															55,286,696
Number of warrants exercised (in shares)					0	7,274,565		0	7,274,565
Stock options outstanding
Earnings Per Share
Number of dilutive potential common stock								24,184,619	9,165,066
Options granted					308,351	117,500		759,851	698,500
Restricted stock outstanding
Earnings Per Share
Number of dilutive potential common stock								5,616,280	6,511,808
Options granted					323,991	98,000		1,126,491	653,000
Common stock warrants
Earnings Per Share
Number of dilutive potential common stock								80,017,181	83,518,821
Convertible senior notes
Earnings Per Share
Number of dilutive potential common stock								39,170,766	39,170,766