| Document And Entity Information | Jun. 22, 2022 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Amendment Flag | false |
| Document Period End Date | Jun. 22, 2022 |
| Entity Registrant Name | ONCORUS, INC. |
| Entity Central Index Key | 0001671818 |
| Entity Emerging Growth Company | true |
| Entity File Number | 001-39575 |
| Entity Incorporation, State or Country Code | DE |
| Entity Tax Identification Number | 47-3779757 |
| Entity Address, Address Line One | 50 Hampshire Street |
| Entity Address, Address Line Two | Suite 401 |
| Entity Address, City or Town | Cambridge |
| Entity Address, State or Province | MA |
| Entity Address, Postal Zip Code | 02139 |
| City Area Code | (857) |
| Local Phone Number | 320-6400 |
| 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 | ONCR |
| Security Exchange Name | NASDAQ |
