Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2019	Mar. 06, 2020	Jun. 30, 2019
Document and Entity Information
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2019
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	FY
Entity Registrant Name	NOVAVAX INC
Entity Central Index Key	0001000694
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Entity Public Float			$ 138,300,000
Entity Voluntary Filers	No
Entity Well-known Seasoned Issuer	Yes
Trading Symbol	NVAX
Entity Common Stock, Shares Outstanding		51,528,841
Entity Interactive Data Current	Yes
Entity Current Reporting Status	Yes
Entity Emerging Growth Company	false
Entity Small Business	true
Entity Shell Company	false