| Document And Entity Information | Apr. 05, 2022 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Amendment Flag | false |
| Document Period End Date | Apr. 5, 2022 |
| Entity Registrant Name | IDEAYA Biosciences, Inc. |
| Entity Central Index Key | 0001676725 |
| Entity Emerging Growth Company | true |
| Entity File Number | 001-38915 |
| Entity Incorporation, State or Country Code | DE |
| Entity Tax Identification Number | 47-4268251 |
| Entity Address, Address Line One | 7000 Shoreline Court |
| Entity Address, City or Town | South San Francisco |
| Entity Address, State or Province | CA |
| Entity Address, Postal Zip Code | 94080 |
| City Area Code | (650) |
| Local Phone Number | 443-6209 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Entity Ex Transition Period | false |
| Title of 12(b) Security | Common Stock, $0.0001 par value per share |
| Trading Symbol | IDYA |
| Security Exchange Name | NASDAQ |
