Marketable Securities (Tables)

3 Months Ended

Mar. 31, 2021

Marketable Securities [Abstract]

Summary of Available-for-Sale Debt Securities

The following table summarizes the available-for-sale debt securities held at March 31, 2021 and December 31, 2020 and (in thousands):

Description	Amortized Cost		Unrealized Gains		Unrealized Losses			Fair Value
March 31, 2021
U.S. treasury securities	$	288,541	$	16	$	—		$	288,557
Corporate securities		93,557		—		(36	)		93,521
Total	$	382,098	$	16	$	(36	)	$	382,078

Description	Amortized Cost		Unrealized Gains		Unrealized Losses			Fair Value
December 31, 2020
U.S. treasury securities	$	324,917	$	—	$	(53	)	$	324,864
Corporate securities		102,946		—		(81	)		102,865
Total	$	427,863	$	—	$	(134	)	$	427,729