Fair Value Measurements (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020	Nov. 30, 2020
Summary of financial instruments measured at fair value on a recurring basis
Non-marketable debt security	$ 0		$ 0		$ 1,000,000
Total					128,567,000
Convertible Debt
Summary of financial instruments measured at fair value on a recurring basis
Credit losses	0	$ 0	0	$ 0
Other-than-temporary impairment losses	0	$ 0	0	$ 0
Money Market Funds
Summary of financial instruments measured at fair value on a recurring basis
Money market funds	95,089,000		95,089,000		127,567,000
Level 1
Summary of financial instruments measured at fair value on a recurring basis
Total					127,567,000
Level 1 | Money Market Funds
Summary of financial instruments measured at fair value on a recurring basis
Money market funds	$ 95,089,000		$ 95,089,000		127,567,000
Level 3
Summary of financial instruments measured at fair value on a recurring basis
Non-marketable debt security					1,000,000	$ 1,000,000
Total					$ 1,000,000