Cover Page - shares	9 Months Ended
	Sep. 30, 2021	Oct. 26, 2021
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2021
Document Transition Report	false
Entity File Number	001-38468
Entity Registrant Name	Inspire Medical Systems, Inc.
Entity Incorporation, State or Country Code	DE
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
Title of 12(b) Security	Common Stock, $0.001 par value per share
Trading Symbol	INSP
Security Exchange Name	NYSE
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding (in shares)		27,358,099
Entity Central Index Key	0001609550
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q3