| Document and Entity Information | Nov. 05, 2019 |
| Cover page. | |
| Entity Registrant Name | INSPIRE MEDICAL SYSTEMS, INC. |
| Entity Central Index Key | 0001609550 |
| Document Type | 8-K |
| Amendment Flag | false |
| Document Period End Date | Nov. 5, 2019 |
| Entity Incorporation, State or Country Code | DE |
| Entity File Number | 001-38468 |
| Entity Tax Identification Number | 26-1377674 |
| Entity Address, Address Line One | 5500 Wayzata Blvd. |
| Entity Address, Address Line Two | Suite 1600 |
| Entity Address, City or Town | Golden Valley |
| Entity Address, State or Province | MN |
| Entity Address, Postal Zip Code | 55416 |
| City Area Code | 844 |
| Local Phone Number | 672-4357 |
| 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 per share |
| Trading Symbol | INSP |
| Security Exchange Name | NYSE |
| Entity Emerging Growth Company | true |
| Entity Ex Transition Period | false |
