Document And Entity Information - shares	3 Months Ended
	Mar. 31, 2020	May 14, 2020
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, 2020
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Entity's Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business Flag	true
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		462,931,961
Document Fiscal Period Focus	Q1
Document Fiscal Year Focus	2020