| Cover | Jan. 12, 2021 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Document Period End Date | Jan. 12, 2021 |
| Entity Registrant Name | Intersect ENT, Inc. |
| Entity Incorporation, State or Country Code | DE |
| Entity File Number | 001-36545 |
| Entity Tax Identification Number | 20-0280837 |
| Entity Address, Address Line One | 1555 Adams Drive |
| Entity Address, City or Town | Menlo Park |
| Entity Address, State or Province | CA |
| Entity Address, Postal Zip Code | 94025 |
| City Area Code | 650 |
| Local Phone Number | 641-2100 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Common stock, $0.001 par value |
| Trading Symbol | XENT |
| Security Exchange Name | NASDAQ |
| Entity Emerging Growth Company | false |
| Amendment Flag | false |
| Entity Central Index Key | 0001271214 |
