Condensed Consolidated Statement of Changes in Stockholders' Equity (Unaudited) - 9 months ended Sep. 30, 2018 - USD ($) $ in Thousands	Common Stock [Member]	Additional Paid-In Capital [Member]	Accumulated Deficit [Member]	Total Equity Attributable to MGT Stockholders [Member]	Non-controlling Interest [Member]	Total
Balance at Dec. 31, 2017	$ 59	$ 390,736	$ (378,900)	$ 11,895	$ (22)	$ 11,873
Balance, shares at Dec. 31, 2017	58,963,009
Stock-based compensation	$ 2	3,446		3,448		3,448
Stock-based compensation, shares	2,860,000
Forfeiture of restricted stock	$ (1)	(232)		(233)		(233)
Forfeiture of restricted stock, shares	(550,000)
Stock issued for services	$ 1	2,035		2,036		2,036
Stock issued for services, shares	1,539,051
Stock issued for prior year notes payable conversion	$ 3	(3)
Stock issued for prior year notes payable conversion, shares	3,381,816
Sale of stock in connection with private placement		80		80		80
Sale of stock in connection with private placement, shares	200,000
Sale of stock in connection with equity purchase agreement	$ 6	565		571		571
Sale of stock in connection with equity purchase agreement, shares	3,950,000
Issuance of common stock for prior year sale	$ 1	(1)
Issuance of common stock for prior year sale, shares	2,000,000
Exercise of warrants	$ 10	897		907		907
Exercise of warrants, shares	9,344,251
Stock issued in disposition of cybersecurity assets		120		120		120
Stock issued in disposition of cybersecurity assets, shares	60,000
Deemed dividend		2,514	(2,514)
Warrant modification expense		139		139		139
Net loss			(18,827)	(18,827)		(18,827)
Balance at Sep. 30, 2018	$ 81	$ 400,296	$ (400,241)	$ 136	$ (22)	$ 114
Balance, shares at Sep. 30, 2018	81,748,127