Marketable Securities - Additional Information (Details)	3 Months Ended		12 Months Ended
	Mar. 31, 2021 USD ($) Security	Mar. 31, 2020 USD ($)	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	32		65
Aggregate fair value of available-for-sale debt securities, continuous unrealized loss position for less than 12 months | $	$ 137,700,000		$ 392,200,000
Number of available-for-sale debt securities, contractual maturity of less than 12 months | Security	47		48
Fair value of available-for-sale debt securities, contractual maturity of less than 12 months | $	$ 280,400,000		$ 295,600,000
Number of available-for-sale debt securities, contractual maturity of greater than 12 months | Security	15		25
Fair value of available-for-sale debt securities, contractual maturity of greater than 12 months | $	$ 101,639,000		$ 162,531,000
Sales of marketable securities | $	$ 0	$ 0
Number of securities decline in market value for in an unrealized loss position | Security	32