Document And Entity Information - shares	3 Months Ended
	Mar. 31, 2018	May 08, 2018
Document And Entity Information
Entity Registrant Name	MGT CAPITAL INVESTMENTS INC
Entity Central Index Key	0001001601
Document Type	10-Q
Document Period End Date	Mar. 31, 2018
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Entity Filer Category	Smaller Reporting Company
Entity Common Stock, Shares Outstanding		70,250,626
Trading Symbol	MGTI
Document Fiscal Period Focus	Q1
Document Fiscal Year Focus	2018