| Document and Entity Information | Apr. 27, 2022 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Amendment Flag | false |
| Document Period End Date | Apr. 27, 2022 |
| Entity Registrant Name | Viking Therapeutics, Inc. |
| Entity Central Index Key | 0001607678 |
| Entity Emerging Growth Company | false |
| Entity File Number | 001-37355 |
| Entity Incorporation, State or Country Code | DE |
| Entity Tax Identification Number | 46-1073877 |
| Entity Address, Address Line One | 9920 Pacific Heights Blvd |
| Entity Address, Address Line Two | Suite 350 |
| Entity Address, City or Town | San Diego |
| Entity Address, State or Province | CA |
| Entity Address, Postal Zip Code | 92121 |
| City Area Code | 858 |
| Local Phone Number | 704-4660 |
| 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 $0.00001 per share |
| Trading Symbol | VKTX |
| Security Exchange Name | NASDAQ |
