Basis of Presentation and Summary of Significant Accounting Policies (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Dec. 31, 2020	Sep. 30, 2020
Accounting Policies [Abstract]
Financing from sale proceeds, debt, and agreement revenues	$ 505,600
Cash and cash equivalents	$ 35,848	$ 31,087	$ 17,843