Fair Value Measurements (Tables)

6 Months Ended

Jun. 30, 2020

Fair Value Disclosures [Abstract]

Financial Assets And Liabilities Subject To Fair Value Measurements On Recurring Basis And Level Of Inputs Used In Such Measurements By Major Security Type

Financial assets and liabilities subject to fair value measurements on a recurring basis and the level of inputs used in such measurements by major security type as of June 30, 2020 and as of December 31, 2019 are presented in the following tables: 

	June 30, 2020
	Level 1		Level 2		Level 3		Fair Value
	(in thousands)
Financial Assets:
Money market funds (1)	$	256,773	$	—	$	—	$	256,773
Commercial paper	—		79,910		—		79,910
Corporate bonds	—		292,055		—		292,055
U.S. treasury securities	423,486		—		—		423,486
U.S. agency securities	—		34,614		—		34,614
Total financial assets	$	680,259	$	406,579	$	—	$	1,086,838

	December 31, 2019
	Level 1		Level 2		Level 3		Fair Value
	(in thousands)
Financial Assets:
Money market funds (1)	$	122,900	$	—	$	—	$	122,900
Corporate bonds	—		205,011		—		205,011
U.S. treasury securities	181,894		—		—		181,894
U.S. agency securities	—		25,824		—		25,824
Certificates of deposit	—		1,000		—		1,000
Total financial assets	$	304,794	$	231,835	$	—	$	536,629

(1)Included within cash and cash equivalents on the Company’s condensed consolidated balance sheets