Summary of Significant Accounting Policies - Narrative (Details) - USD ($)	3 Months Ended			6 Months Ended	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Jun. 30, 2020	Jun. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Accounting Policies [Abstract]
Unrealized gain (loss) on available for sale securities	$ (81,000)	$ 0			$ (143,000)	$ 0
Unrealized gain (loss) on equity securities	(22,285,000)	0	$ 0	$ 0	$ (51,250,000)	0
Stated term					1 year
Renewal option term					1 year
Term for students					2 years
Deferred revenue	4,500,000				$ 4,500,000		$ 1,900,000
Stock based compensation	$ 1,700,000	$ 300,000			$ 8,813,000	$ 941,000