| Document and Entity Information | Sep. 19, 2023 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Entity Ex Transition Period | false |
| Amendment Flag | false |
| Document Period End Date | Sep. 19, 2023 |
| Entity Registrant Name | IMPEL PHARMACEUTICALS INC. |
| Entity Central Index Key | 0001445499 |
| Entity Emerging Growth Company | true |
| Security12b Title | Common Stock, $0.001 Par Value Per Share |
| Trading Symbol | IMPL |
| Security Exchange Name | NASDAQ |
| Entity File Number | 001-40353 |
| Entity Incorporation State Country Code | DE |
| Entity Tax Identification Number | 26-3058238 |
| Entity Address Address Line1 | 201 Elliott Avenue West |
| Entity Address, Address Line Two | Suite 260 |
| Entity Address City Or Town | Seattle |
| Entity Address State Or Province | WA |
| Entity Address Postal Zip Code | 98119 |
| City Area Code | 206 |
| Local Phone Number | 568-1466 |
| Entity Information, Former Legal or Registered Name | Impel NeuroPharma, Inc. |
| Written Communications | false |
| Soliciting Material | false |
| Pre Commencement Tender Offer | false |
| Pre Commencement Issuer Tender Offer | false |
