Restatement of previously issued financial statements (Details 1) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Selling, general and administrative	$ 815	$ 1,807	$ 2,719	$ 6,219
Operating loss	(811)	(1,948)	(2,618)	(6,960)
Revaluation of warrant liability	623		13
Net loss as reported	(479)	(1,948)	(2,997)	(6,796)
Net loss attributable to non-controlling interest	114	746	526	2,652
Net loss attributable to MGT Capital Investments, Inc.	(365)	(1,202)	(2,471)	(4,144)
Comprehensive loss attributable to non-controlling interest	113	775	493	2,517
Comprehensive loss attributable to MGT Capital Investments, Inc.	(361)	(1,239)	(2,431)	(3,941)
Basic and diluted loss per share (in dollars per share)	$ (0.17)	$ (1.03)	$ (1.16)	$ (3.54)
Scenario, Previously Reported [Member]
Selling, general and administrative	716		2,620
Operating loss	(712)		(2,519)
Revaluation of warrant liability	0		0
Net loss as reported	(1,003)		(2,911)
Net loss attributable to non-controlling interest	113		525
Net loss attributable to MGT Capital Investments, Inc.	(890)		(2,386)
Comprehensive loss attributable to non-controlling interest	112		492
Comprehensive loss attributable to MGT Capital Investments, Inc.	$ (886)		$ (2,346)
Basic and diluted loss per share (in dollars per share)	$ (0.41)		$ (1.12)