Summary of Significant Accounting Policies - Cash and Cash Equivalents (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Restricted Cash	$ 800	$ 900	$ 800
Amount of unrealized gain loss on investments	0	0
Letter of Credit
Restricted Cash	$ 800	$ 800
Restricted Cash, Asset, Statement of Financial Position [Extensible List]	Other Assets, Noncurrent	Other Assets, Noncurrent