Cover - USD ($)	12 Months Ended
	Dec. 31, 2021	Mar. 30, 2022	Jun. 30, 2021
Cover [Abstract]
Document Type	10-K
Document Annual Report	true
Current Fiscal Year End Date	--12-31
Document Period End Date	Dec. 31, 2021
Document Transition Report	false
Entity File Number	001-35518
Entity Registrant Name	SUPERNUS PHARMACEUTICALS, INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	20-2590184
Entity Address, Address Line One	9715 Key West Avenue
Entity Address, City or Town	Rockville
Entity Address, State or Province	MD
Entity Address, Postal Zip Code	20850
City Area Code	(301)
Local Phone Number	838-2500
Title of 12(b) Security	Common Stock, $0.001 Par Value
Entity Common Stock, Shares Outstanding		53,386,305
Trading Symbol	SUPN
Security Exchange Name	NASDAQ
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
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
ICFR Auditor Attestation Flag	true
Entity Shell Company	false
Entity Public Float			$ 1,634,702,733
Documents Incorporated by Reference	Certain portions of the registrant's definitive Proxy Statement for its 2022 Annual Meeting of Stockholders, which will be filed with the Securities and Exchange Commission not later than 120 days after the end of the registrant's 2021 fiscal year end, are incorporated by reference into Part III of this Annual Report on Form 10-K.
Entity Central Index Key	0001356576
Amendment Flag	false
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	FY