Subsequent Events (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended						2 Months Ended	3 Months Ended			6 Months Ended		9 Months Ended		12 Months Ended
	Feb. 28, 2021	Jan. 31, 2021	Nov. 30, 2020	Aug. 31, 2020	Dec. 31, 2019	Mar. 31, 2019	Feb. 28, 2021	Dec. 31, 2020	Mar. 31, 2020	Mar. 31, 2019	Jun. 30, 2020	Jun. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	May 31, 2020	May 29, 2020	May 18, 2020
Subsequent Events
Public offerings, common stock, net (in shares)			43,700,000	35,276,250	46,000,000	10,000,000		4,400,000							79,000,000.0
Proceeds from public offerings, net of transaction costs			$ 927,300	$ 344,400	$ 120,400	$ 23,500				$ 23,498	$ (269)	$ 28,265	$ 344,398	$ 38,098	$ 1,271,714	$ 158,343	$ 7,195
Conversion of preferred stock to common stock									$ 441		$ 441		$ 43,058	$ 1,883	$ 1,179	$ 28,392
Interest rate (as a percent)																		3.50%
Common stock, shares issued					318,637,560			473,977,469							473,977,469	318,637,560
Share price (in dollars per share)			$ 22.25	$ 10.25	$ 2.75	$ 2.35				$ 2.35						$ 2.75
3.75% Convertible Senior Notes
Subsequent Events
Interest rate (as a percent)								3.75%							3.75%			3.75%	3.75%	3.75%
Share price (in dollars per share)								$ 33.91							$ 33.91
Subsequent event
Subsequent Events
Public offerings, common stock, net (in shares)							32.2
Subsequent event | SK Holdings Co LTD
Subsequent Events
Public offerings, common stock, net (in shares)	54,996,188
Per share price of shares of common stock	$ 29.2893						$ 29.2893
Proceeds from public offerings, net of transaction costs	$ 1,600,000
Common stock, shares issued	54,966,188						54,966,188
Subsequent event | 3.75% Convertible Senior Notes
Subsequent Events
Conversion of preferred stock to common stock	$ 15,200	$ 15,200					$ 15,200
Interest rate (as a percent)	3.75%	3.75%					3.75%
Conversion of notes through common stock issuance	3,000,000.0	3,000,000.0					3,000,000.0
Subsequent event | Public Offerings
Subsequent Events
Public offerings, common stock, net (in shares)	32,200,000	32,200,000
Proceeds from public offerings, net of transaction costs	$ 1,800,000	$ 1,800,000
Share price (in dollars per share)	$ 65.00	$ 65.00					$ 65.00