Fair Value of Financial Instruments (Tables)

12 Months Ended

Dec. 31, 2021

Fair Value Disclosures [Abstract]

Schedule of Fair Value Measurements of Financial Assets and Liabilities

The following table details the fair value measurements within the fair value hierarchy of the Company’s financial assets and liabilities at December 31, 2021 and December 31, 2020 :

	December 31, 2021
	Level 1		Level 2		Level 3		Total
	(in thousands)
Cash equivalents and investments:
Money market funds	$	125,940	$	—	$	—	$	125,940
Commercial paper		—		28,337		—		28,337
Corporate bonds		—		249,846		—		249,846
U.S. Government agency securities		—		22,466		—		22,466
U.S. Treasury securities		—		698,300		—		698,300
Restricted cash:
Money market funds		—		3,029		—		3,029
Total	$	125,940	$	1,001,978	$	—	$	1,127,918

	December 31, 2020
	Level 1		Level 2		Level 3		Total
	(in thousands)
Cash equivalents and investments:
Money market funds	$	172,485	$	—	$	—	$	172,485
Commercial paper		—		12,233		—		12,233
Corporate bonds		—		116,371		—		116,371
U.S. Treasury securities		—		774,772		—		774,772
Certificates of deposit		—		394		—		394
Restricted cash:
Money market funds		—		3,029		—		3,029
Total	$	172,485	$	906,799	$	—	$	1,079,284

Summary of Composition of Short and Long Term Investments

The following tables summarize the composition of our short- and long-term investments at December 31, 2021 and 2020:

	December 31, 2021
	Amortized Cost		Unrealized Gains		Unrealized Losses			Aggregate Fair Value
	(in thousands)
Commercial paper	$	25,245	$	—	$	—		$	25,245
Corporate bonds		250,443		9		(606	)		249,846
U.S. Government agency securities		22,504		—		(38	)		22,466
U.S. Treasury securities		698,446		2		(148	)		698,300
Total	$	996,638	$	11	$	(792	)	$	995,857

	December 31, 2020
	Amortized Cost		Unrealized Gains		Unrealized Losses			Aggregate Fair Value
	(in thousands)
Commercial paper	$	12,233	$	—	$	—		$	12,233
Corporate bonds		115,983		427		(39	)		116,371
U.S. Treasury securities		774,667		105		—			774,772
Certificates of deposit		394		—		—			394
Total	$	903,277	$	532	$	(39	)	$	903,770

Summary of Contractual Maturities of Short and Long Term Investments

The contractual maturities of short-term and long-term investments held as follows:

	December 31, 2021				December 31, 2020
	Amortized Cost Basis		Aggregate Fair Value		Amortized Cost Basis		Aggregate Fair Value
	( in thousands)
Due within one year	$	821,101	$	820,962	$	872,637	$	873,073
Due after 1 year and within 2 years		175,537		174,895		30,640		30,697
Total	$	996,638	$	995,857	$	903,277	$	903,770