| Cover | May 29, 2020 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Amendment Flag | false |
| Document Period End Date | May 29, 2020 |
| Entity File Number | 001-31913 |
| Entity Registrant Name | NOVAGOLD RESOURCES INC. |
| Entity Central Index Key | 0001173420 |
| Entity Incorporation, State or Country Code | A1 |
| Entity Address, Address Line One | 201 South Main Street |
| Entity Address, Address Line Two | Suite 400 |
| Entity Address, City or Town | Salt Lake City |
| Entity Address, State or Province | UT |
| Entity Address, Postal Zip Code | 84111 |
| City Area Code | (801) |
| Local Phone Number | 639-0511 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Common Shares |
| Trading Symbol | NG |
| Security Exchange Name | NYSEAMER |
| Entity Emerging Growth Company | false |
