Marketable Securities (Tables)

12 Months Ended

Dec. 31, 2022

Investments, Debt and Equity Securities [Abstract]

Summary of Available for Sale Securities

The amortized cost, gross unrealized holding gains or losses, and fair value of the Company’s marketable securities by major security type at each balance sheet date are summarized in the tables below (in thousands):

	December 31, 2022
	Amortized Cost		Unrealized Holding Gains		Unrealized Holding Losses		Aggregate Fair Value
Short-term marketable securities:
U.S. government treasuries(1)	$	1,009,733	$	58	$	(6,287)	$	1,003,504
U.S. government agency securities	16,823		38		—		16,861
Corporate debt securities(2)	54,571		—		(356)		54,215
Commercial paper	43,591		—		—		43,591
Total short-term marketable securities	1,124,718		96		(6,643)		1,118,171
Total	$	1,124,718	$	96	$	(6,643)	$	1,118,171

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(1)Unrealized holding losses on 51 securities with an aggregate fair value of $683.4 million.

(2)Unrealized holding losses on 16 securities with an aggregate fair value of $54.2 million.

	December 31, 2021
	Amortized Cost		Unrealized Holding Gains		Unrealized Holding Losses		Aggregate Fair Value
Short-term marketable securities:
U.S. government treasuries(1)	$	450,689	$	—	$	(253)	$	450,436
Corporate debt securities(2)	70,076		1		(68)		70,009
Commercial paper	51,485		—		—		51,485
Total short-term marketable securities	572,250		1		(321)		571,930
Long-term marketable securities:
U.S. government treasuries(3)	411,904		—		(1,757)		410,147
Corporate debt securities(4)	15,373		—		(71)		15,302
Total long-term marketable securities	427,277		—		(1,828)		425,449
Total	$	999,527	$	1	$	(2,149)	$	997,379

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(1)Unrealized holding losses on 19 securities with an aggregate fair value of $450.4 million.

(2)Unrealized holding losses on 16 securities with an aggregate fair value of $68.5 million.

(3)Unrealized holding losses on 16 securities with an aggregate fair value of $410.1 million.

(4)Unrealized holding losses on 6 securities with an aggregate fair value of $15.3 million.