| Document and Entity Information | Mar. 28, 2022 |
| Cover [Abstract] | |
| Amendment Flag | false |
| Entity Central Index Key | 0001645460 |
| Document Type | 8-K |
| Document Period End Date | Mar. 28, 2022 |
| Entity Registrant Name | Cue Biopharma, Inc. |
| Entity Incorporation State Country Code | DE |
| Entity File Number | 001-38327 |
| Entity Tax Identification Number | 47-3324577 |
| Entity Address, Address Line One | 21 Erie St. |
| Entity Address, City or Town | Cambridge |
| Entity Address, State or Province | MA |
| Entity Address, Postal Zip Code | 02139 |
| City Area Code | (617) |
| Local Phone Number | 949-2680 |
| Written Communications | false |
| Soliciting Material | false |
| Pre Commencement Tender Offer | false |
| Pre Commencement Issuer Tender Offer | false |
| Security 12b Title | Common Stock, par value $0.001 per share |
| Trading Symbol | CUE |
| Security Exchange Name | NASDAQ |
| Entity Emerging Growth Company | true |
| Entity Ex Transition Period | true |
