Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2019	Jan. 30, 2020	Jun. 30, 2019
Document and Entity Information [Abstract]
Entity Registrant Name	SPHERIX INC
Entity Central Index Key	0000012239
Document Type	10-K
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	FY
Amendment Flag	false
Document Period End Date	Dec. 31, 2019
Entity File Number	000-05576
Entity Reporting Status Current	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		4,825,549
Entity Incorporation, State or Country Code	DE
Entity Public Float			$ 5,730,248