Marketable Securities - Additional Information (Details)	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2021 USD ($) Security	Jun. 30, 2020 USD ($)	Jun. 30, 2021 USD ($) Security	Jun. 30, 2020 USD ($)	Dec. 31, 2020 USD ($) Security
Marketable Securities [Abstract]
Number of available-for-sale debt securities, continuous unrealized loss position for less than 12 months | Security	28		28		65
Aggregate fair value of available-for-sale debt securities, continuous unrealized loss position for less than 12 months | $	$ 91,000,000.0		$ 91,000,000.0		$ 392,200,000
Number of available-for-sale debt securities, contractual maturity of less than 12 months | Security			43		48
Fair value of available-for-sale debt securities, contractual maturity of less than 12 months | $	274,200,000		$ 274,200,000		$ 295,600,000
Number of available-for-sale debt securities, contractual maturity of greater than 12 months | Security			12		25
Fair value of available-for-sale debt securities, contractual maturity of greater than 12 months | $	45,305,000		$ 45,305,000		$ 162,531,000
Sales of marketable securities | $	$ 0	$ 0	$ 0	$ 0
Number of securities decline in market value for in an unrealized loss position | Security			28