| Cover | Dec. 05, 2020 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Amendment Flag | false |
| Document Period End Date | Dec. 5, 2020 |
| Entity File Number | 0-26770 |
| Entity Registrant Name | NOVAVAX, INC. |
| Entity Central Index Key | 0001000694 |
| Entity Tax Identification Number | 22-2816046 |
| Entity Incorporation, State or Country Code | DE |
| 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 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Common Stock, Par Value $0.01 per share |
| Trading Symbol | NVAX |
| Security Exchange Name | NASDAQ |
| Entity Emerging Growth Company | false |
