Stockholders' Equity (Deficit) (Details) - USD ($) $ in Thousands	1 Months Ended			3 Months Ended
	Jan. 31, 2021	Jan. 20, 2021	Nov. 30, 2020	Mar. 31, 2021	Mar. 31, 2020
Stockholders' Equity
Proceeds from shares sold, net				$ 564,859	$ 185,918
Common Stock
Stockholders' Equity
Proceeds from shares sold, net				$ 26	$ 215
Issued (in shares)				2,578,967	21,473,731
Market Issuance Sales Agreements | Common Stock
Stockholders' Equity
Proceeds from shares sold, net					$ 185,900
Issued (in shares)					21,500,000
January 2021 Issuance Sales Agreement
Stockholders' Equity
Proceeds from shares sold, net				$ 452,000
Issued (in shares)				1,700,000
Remaining unissued capital		$ 27,200		$ 42,200
January 2021 Issuance Sales Agreement | Common Stock
Stockholders' Equity
Proceeds from shares sold, net	$ 500,000
November 2020 Issuance Sales Agreement
Stockholders' Equity
Proceeds from shares sold, net		$ 113,000
Issued (in shares)		900,000
November 2020 Issuance Sales Agreement | Common Stock
Stockholders' Equity
Proceeds from shares sold, net			$ 500,000