Cover Page - USD ($)	12 Months Ended
	Dec. 31, 2020	Feb. 24, 2021	Jun. 30, 2020
Cover [Abstract]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2020
Current Fiscal Year End Date	--12-31
Document Transition Report	false
Entity File Number	000-26770
Entity Registrant Name	NOVAVAX, INC
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	22-2816046
Entity Address, Address Line One	21 Firstfield Road,
Entity Address, City or Town	Gaithersburg,
Entity Address, State or Province	MD
Entity Address, Postal Zip Code	20878
City Area Code	(240)
Local Phone Number	268-2000
Title of 12(b) Security	Common Stock, Par Value $0.01 per share
Trading Symbol	NVAX
Security Exchange Name	NASDAQ
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Emerging Growth Company	false
Entity Small Business	false
ICFR Auditor Attestation Flag	true
Entity Shell Company	false
Entity Public Float			$ 5,078,700,000
Entity Common Stock, Shares Outstanding		73,858,882
Documents Incorporated by Reference	Documents incorporated by reference: Portions of the Registrant’s Definitive Proxy Statement to be filed no later than 120 days after the fiscal year ended December 31, 2020 in connection with the Registrant’s 2020 Annual Meeting of Stockholders are incorporated by reference into Part III of this Annual Report on Form 10-K to the extent indicated herein.
Entity Central Index Key	0001000694
Document Fiscal Year Focus	2020
Amendment Flag	false
Document Fiscal Period Focus	FY