| Document and Entity Information | Feb. 09, 2022 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Amendment Flag | false |
| Document Period End Date | Feb. 9, 2022 |
| Entity Registrant Name | Impinj, Inc. |
| Entity Central Index Key | 0001114995 |
| Entity Incorporation State Country Code | DE |
| Entity Address, State or Province | WA |
| Entity File Number | 001-37824 |
| Entity Tax Identification Number | 91-2041398 |
| Entity Address, Address Line One | 400 Fairview Avenue North |
| Entity Address, Address Line Two | Suite 1200 |
| Entity Address, City or Town | Seattle |
| Entity Address, Postal Zip Code | 98109 |
| City Area Code | 206 |
| Local Phone Number | 517-5300 |
| 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 | PI |
| Security Exchange Name | NASDAQ |
| Entity Emerging Growth Company | false |
