DOCUMENT AND ENTITY INFORMATION (USD $)	12 Months Ended
	Dec. 31, 2012	Mar. 28, 2013	Jun. 30, 2012
Entity Registrant Name	MGT CAPITAL INVESTMENTS INC
Entity Central Index Key	0001001601
Current Fiscal Year End Date	--12-31
Entity Filer Category	Smaller Reporting Company
Trading Symbol	mgt
Entity Common Stock, Shares Outstanding		3,522,935
Document Type	10-K
Amendment Flag	true
Amendment Description	This Amendment No. 2 hereby amends our Annual Report on Form 10-K ("Form 10-K/A") for the year ended December 31, 2012, which was originally filed with the Securities and Exchange Commission on March 29, 2013 (the "Original 10-K") and subsequently amended on April 30, 2013 to include Part III information. This Amendment is being filed mainly to include restated financial statements as described in Note 1, "Restatement of previously issued financial statements", of the Notes to the Consolidated Statements. The consolidated statements are being restated to correct accounting errors as follows: On May 15, 2013, after consulting with the Company's Audit Committee, management concluded that certain of the Company's warrants ("J&S Warrants") and its Series A Convertible Preferred Stock ("Preferred Stock") received improper accounting treatment. The warrants should have been reflected as liabilities and the Preferred Stock should have been reflected as temporary equity on the balance sheet included in the Company's previously filed Annual Report on Form 10-K for the year ended December 31, 2012 (the "Annual Report"), as opposed to a component of equity. Specifically, due to certain anti-dilution provisions contained in the J&S Warrants, they are being reclassified to liabilities and will be marked-to-market each reporting period. The change in treatment of the warrants will result in a change to the equity and liability portions of the balance sheet at the aforementioned reporting date and will result in a loss on the revaluation of the warrants which impacts results of operations and loss per share as reported in our statement of operations for the period. In addition, the Company previously determined the fair value using the Black Scholes Model; however, due to the anti-dilution provisions, the Company determined the Binomial Lattice Practice Model was more appropriate. The use of the Binomial Lattice Practice Model caused an increase in the fair value of the J&S Warrants issued as consideration for the acquisition of the Patent which increased the amount recorded for the intangible asset and non-controlling interest. Such restatements for the correction of an error, however, will not impact cash flow or cash balances. In addition, as a result of Waiver Agreements obtained on May 20, 2013 from warrant holders, which removed the anti-dilution provision, the affected warrants will be treated as equity at June 30, 2013. Investors should be aware that the classification of the warrants as a liability will revert back to the originally reported equity treatment during the quarter ending June 30, 2013. The Preferred Stock Certificate of Designation and Warrant agreement each contain a fundamental transactions clause that provides for the conditional redemption of these instruments under certain circumstances that are not within the Company's sole control. Management has therefore concluded that the preferred stock requires temporary equity classification at its allocated values and the warrants require classification as a liability at fair value. When the Preferred stock and Warrants were issued, the fair value of the warrants exceeded the proceeds received from the sale and issuance of the Preferred Stock and Warrants. The Warrants were recorded at their fair value and the excess over the proceeds received was recorded as a deemed dividend. Changes in the fair value of the Warrants at each reporting date are included in the statement of operations. Lastly, as of the date of this Form 10-K/A, substantially all of the Preferred Stock has converted into Common Stock of the Company pursuant to its terms; and therefore the conversion of the Preferred Stock eliminates the classification of these shares as temporary equity as well. In addition, as a result of Waiver Agreements obtained on May 20, 2013 from warrant holders, which removed a fundamental transactions clause that provides for the conditional redemption of these instruments under certain circumstances that are not within the Company's sole control, the affected warrants will be treated as equity at June 30, 2013. Investors should be aware that the classification of the warrants as a liability will revert back to the originally reported equity treatment during the quarter ending June 30, 2013. As part of the restatement process, the Company recorded adjustments for items that were previously considered insignificant and were not recorded in the reporting period. In addition, the Company has concluded that these accounting and reporting errors constituted an additional deficiency in the Company's internal control over financial reporting as of December 31, 2012 and that its disclosure controls and procedures were not effective at December 31, 2012. The following sections of this Form 10-K/A have been amended to reflect the restatement: Part II - Item 7 - Management's Discussion and Analysis of Financial Condition and Result of Operations. Part II - Item 8 - Financial Statements and Notes to the Consolidated Financial Statements. Part II - Item 9A - Controls and Procedures. For the convenience of the reader, this Form 10-K/A sets forth the Company's Original 10-K in its entirety, as amended by, and to reflect the restatement, as described above.  Except as discussed above, the Company has not modified or updated disclosures presented in this Amendment.  Accordingly, this Amendment does not reflect events occurring after the Original 10-K or modify or update those disclosures affected by subsequent events, except as specifically referenced herein. Information not affected by the restatement is unchanged and reflects the disclosures made at the time of the Filing of the Original 10-K. This Form 10-K/A has been signed as of a current date and all certifications of the Company's Chief Executive Officer/Principal Executive Officer and Chief Financial Officer/Chief Accounting Officer and Principal Financial Officer are given as of a current date.  Accordingly, this Form 10-K/A should be read in conjunction with the Company's filings with the Securities and Exchange Commission subsequent to the filing of the Original 10-K, including any amendments to those filings.
Document Period End Date	Dec. 31, 2012
Document Fiscal Period Focus	FY
Document Fiscal Year Focus	2012
Entity Well-Known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Public Float			$ 6,477,983