Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2018	Feb. 15, 2019	Jun. 29, 2018
Document and Entity Information
Entity Registrant Name	Inspire Medical Systems, Inc.
Entity Central Index Key	0001609550
Document Type	10-K
Document Period End Date	Dec. 31, 2018
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Entity Current Reporting Status	Yes
Entity Filer Category	Non-accelerated Filer
Entity Shell Company	false
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Ex Transition Period	false
Entity Public Float			$ 409,079,895
Entity Common Stock, Shares Outstanding (in shares)		23,437,729
Document Fiscal Year Focus	2018
Document Fiscal Period Focus	Q4
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No