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Additional Paid-In Capital (Summary Of The Status Of Unvested Stock Options) (Details) (USD $) | 12 Months Ended |
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Dec. 31, 2014 | Dec. 31, 2013 | Dec. 31, 2012
Additional Paid-In Capital [Abstract] |  |  |
Unvested, Number of options (in shares) | 246,250 vgz_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsNonvestedNumberOutstanding | 738,750 vgz_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsNonvestedNumberOutstanding | 300,000 vgz_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsNonvestedNumberOutstanding
Granted, Number of options (in shares) | 175,000 us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross | 985,000 us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross |
Vested, Number of options (in shares) | (667,500)vgz_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedDuringPeriod | (546,250)vgz_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedDuringPeriod |
Unvested, Weighted average grant-date fair value per option (in dollars per share) | $ 0.22 vgz_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsNonvestedWeightedAverageGrantDateFairValue | $ 0.22 vgz_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsNonvestedWeightedAverageGrantDateFairValue | $ 1.47 vgz_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsNonvestedWeightedAverageGrantDateFairValue
Granted, Weighted average grant-date fair value per option (in dollars per share) | $ 0.30 us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue | $ 0.22 us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue |
Vested, weighted average grant-date fair value per option (in dollars per share) | $ (0.24)vgz_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedDuringPeriodWeightedAverageGrantDatePrice | $ (0.90)vgz_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedDuringPeriodWeightedAverageGrantDatePrice |
Weighted average remaining amortization period | 3 years 11 months 27 days |  |

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- Details
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- Definition Weighted average period over which unrecognized compensation is expected to be recognized for equity-based compensation plans, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (i) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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- Definition Gross number of share options (or share units) granted during the period. + References No definition available. + Details
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- Definition The weighted average grant-date fair value of options granted during the reporting period as calculated by applying the disclosed option pricing methodology. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (d)(1) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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- Definition The number of non-vested stock (or unit) options, that validly exist and are outstanding as of the balance sheet date. + References No definition available. + Details
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- Definition The weighted average grant-date fair value of options outstanding as of the balance sheet date as calculated by applying the disclosed option pricing methodology. + References No definition available. + Details
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- Definition Non vested options at the beginning of the period that vest during the period. + References No definition available. + Details
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- Definition Nov vested options at the beginning of the period that vest during the period, price per option. + References No definition available. + Details
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