Consolidated Statement of Changes in Stockholders' (Deficit) Equity - USD ($) $ in Thousands	Preferred Stock [Member]	Common Stock [Member]	Additional Paid-In Capital [Member]	Accumulated Deficit [Member]	Accumulated Other Comprehensive Loss [Member]	Total (Deficit) Equity Attributable to MGT Stockholders [Member]	Noncontrolling Interest [Member]	Total
Balance at Dec. 31, 2015		$ 18	$ 311,167	$ (303,944)	$ (1,206)	$ 6,035	$ 5	$ 6,040
Balance, shares at Dec. 31, 2015	10,838	17,928,221
Stock-based compensation		$ 3	9,679			9,682		9,682
Stock-based compensation, shares		3,151,500
Stock issued for services		$ 1	1,106			1,107		1,107
Stock issued for acquisitions of intangible assets			495			495		495
Stock issued for acquisitions of intangible assets,shares		150,000
Stock issued for exchange of warrants		$ 1	832			833		833
Stock issued for exchange of warrants, shares		540,000
Exercise of warrants		$ 6	2,421			2,427		2,427
Exercise of warrants, shares		6,177,296
Warrant modification expense			431			431		431
Acquisition of non-controlling interest			(292)			(292)	292
Conversion of Preferred Series A into Common stock
Conversion of Preferred Series A into Common stock, shares	(10,838)	10,838
Fair value of warrants issued in connection with notes payable			761			761		761
Stock issued for acquisitions								$ 495
Stock issued for acquisitions, shares								150,000
Beneficial conversion feature on convertible notes			702			702		$ 702
Fair value of vested stock options			641			641		641
Net loss for the period				(24,523)		(24,523)	(319)	(24,523)
Unrealized holding loss on available for sale investments					(313)	(313)		(313)
Reclassification adjustment upon sale of available for sale investments into net loss					1,453	1,453	(319)	1,134
Balance at Dec. 31, 2016		$ 29	327,943	(328,467)	(66)	(561)	(22)	(583)
Balance, shares at Dec. 31, 2016		28,722,855
Stock-based compensation		$ 4	3,276			3,280		3,280
Stock-based compensation, shares		4,050,000
Stock issued for services		$ 3	4,626			4,629		4,725
Stock issued for services, shares		2,574,000
Exercise of warrants		$ 8	387			395		395
Exercise of warrants, shares		7,693,588
Warrant modification expense
Stock issued for acquisitions		$ 2	2,498			2,500		2,500
Stock issued for acquisitions, shares		2,000,000
Beneficial conversion feature on convertible notes			4,593			4,593		4,593
Net loss for the period				(48,861)		(48,861)		(50,433)
Unrealized holding loss on available for sale investments
Reclassification adjustment upon sale of available for sale investments into net loss					66	66		66
Stock issued in exchange of notes payables		$ 10	8,670			8,676		8,676
Stock issued in exchange of notes payables,shares		10,191,466
Induced conversion of notes payable			20,312			20,312		20,312
Stock sold in connection with private placements		$ 3	9,147			9,150		9,150
Stock sold in connection with private placements,shares		2,875,000
Stock issued in exchange of accounts payable			401			401		401
Stock issued in exchange of accounts payable,shares		220,000
Sale of common stock warrants			100			100		100
Stock issued in connection with notes payable amendment			118			118		118
Stock issued in connection with notes payable amendment, shares		200,000
Amortization of employee stock options			7,057			7,057		7,057
Modification of employee stock options			37			37		37
Stock and warrants issued in connection with Management Agreements		$ 1	1,571			1,571		1,571
Stock and warrants issued in connection with Management Agreements,shares		436,100
Balance at Dec. 31, 2017		$ 59	$ 390,739	$ (378,900)		$ 11,895	$ (22)	$ 11,873
Balance, shares at Dec. 31, 2017		58,963,009