Summary of Significant Accounting Policies - Changes in Deferred Revenue (Details) - USD ($) $ in Thousands	3 Months Ended
	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019
Contract with customer, Liability [Roll Forward]
Deferred revenue, beginning	$ 22,494	$ 23,969	$ 11,054	$ 9,666	$ 10,415	$ 10,237
Deferral of revenue	10,547	5,699	19,149	5,630	5,004	5,389
Recognition of unearned revenue	(12,923)	(7,174)	(6,234)	(5,512)	(5,753)	(5,211)
Deferred revenue, ending	$ 20,118	$ 22,494	$ 23,969	$ 9,784	$ 9,666	$ 10,415