Represents the amount of advance royalties to be paid per year.

No definition available.

Name:	ctgo_AdvanceRoyaltiesToBePaidPerYear
Namespace Prefix:	ctgo_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Represents the amount of annual claim rentals payable, as of the balance sheet date.

+ References

No definition available.

+ Details

Name:	ctgo_AnnualClaimRentals
Namespace Prefix:	ctgo_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The amount of salary and compensation retention agreement that is contingently payable.

+ References

No definition available.

+ Details

Name:	ctgo_ContingentSalaryAndCompensationRetentionAgreement
Namespace Prefix:	ctgo_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Represents the contractual exploration costs to be paid per year, pursuant to the terms of the agreement.

+ References

No definition available.

+ Details

Name:	ctgo_ContractualAnnualExplorationCosts
Namespace Prefix:	ctgo_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Represents the reduction in the percentage of the royalty payable.

+ References

No definition available.

+ Details

Name:	ctgo_DecreaseInRoyaltyRates
Namespace Prefix:	ctgo_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Represents the extension of the term of leases and concessions on undeveloped acreage.

+ References

No definition available.

+ Details

Name:	ctgo_ExtensionOfTermOfLeasesAndConcessionsOnUndevelopedAcreage
Namespace Prefix:	ctgo_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the payments that have been made, inception-to-date, to reduce the royalty rate under an agreement.

+ References

No definition available.

+ Details

Name:	ctgo_InceptionToDatePaymentsToReduceRoyaltyRate
Namespace Prefix:	ctgo_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Represents an increase in the percentage of the royalty payable.

+ References

No definition available.

+ Details

Name:	ctgo_IncreaseInRoyaltyRates
Namespace Prefix:	ctgo_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Represents the initial term of leases and concessions on undeveloped acreage.

+ References

No definition available.

+ Details

Name:	ctgo_InitialTermOfLeasesAndConcessionsOnUndevelopedAcreage
Namespace Prefix:	ctgo_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

The percent of net smelter returns royalty interest.

+ References

No definition available.

+ Details

Name:	ctgo_NetSmelterReturnsRoyaltyInterestPercent
Namespace Prefix:	ctgo_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

The percent of net smelter returns silver royalty.

+ References

No definition available.

+ Details

Name:	ctgo_NetSmelterReturnsSilverRoyaltyPercent
Namespace Prefix:	ctgo_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Represents the overriding royalty interest the company would be required to pay if any of the properties are placed into commercial production.

+ References

No definition available.

+ Details

Name:	ctgo_OverridingRoyaltyInterest
Namespace Prefix:	ctgo_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Represents the amount of payment that the lessor may make to the lessee in order to increase the royalty rate by a specified percentage.

+ References

No definition available.

+ Details

Name:	ctgo_PaymentThatLessorMayPayToLesseeToIncreaseRoyaltyRate
Namespace Prefix:	ctgo_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Represents the royalty rate required to be paid under an agreement.

+ References

No definition available.

+ Details

Name:	ctgo_RoyaltyRate
Namespace Prefix:	ctgo_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

The percentage of base salary of payout if all performance goals are met under the short term incentive plan.

+ References

No definition available.

+ Details

Name:	ctgo_ShortTermIncentivePlanAllPerformanceGoalsPayoutPercentageOfBaseSalary
Namespace Prefix:	ctgo_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

The maximum period for payment to be made in the event of change of control under the short term incentive plan.

+ References

No definition available.

+ Details

Name:	ctgo_ShortTermIncentivePlanChangeOfControlMaximumPeriodOfPayment
Namespace Prefix:	ctgo_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

The percentage of base salary to be paid in the event of change of control under the short term incentive plan.

+ References

No definition available.

+ Details

Name:	ctgo_ShortTermIncentivePlanChangeOfControlPercentageOfBaseSalary
Namespace Prefix:	ctgo_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

The percentage of base salary to be paid if maximum performance targets are met under the short term incentive plan.

+ References

No definition available.

+ Details

Name:	ctgo_ShortTermIncentivePlanMaximumPerformanceTargetPayoutPercentageOfBaseSalary
Namespace Prefix:	ctgo_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

The percentage of base salary to be paid if minimum performance target is met under the short term incentive plan.

+ References

No definition available.

+ Details

Name:	ctgo_ShortTermIncentivePlanMinimumPerformanceTargetPayoutPercentageOfBaseSalary
Namespace Prefix:	ctgo_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

The percentage of the payout to be paid in cash under the short term incentive agreement.

+ References

No definition available.

+ Details

Name:	ctgo_ShortTermIncentivePlanPayoutPercentageCash
Namespace Prefix:	ctgo_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

The percentage of the payout to be paid in the form of restricted stock under the short term incentive plan.

+ References

No definition available.

+ Details

Name:	ctgo_ShortTermIncentivePlanPayoutPercentageRestrictedStock
Namespace Prefix:	ctgo_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Represents cash bonus for short-term incentive plan compensation expenses.

+ References

No definition available.

+ Details

Name:	ctgo_ShorttermIncentivePlanCompensationExpenseCashBonus
Namespace Prefix:	ctgo_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Period over which grantee's right to exercise award under share-based payment arrangement is no longer contingent on satisfaction of service or performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Includes, but is not limited to, combination of market, performance or service condition.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(2)(iii)(1)
-URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_AwardTypeAxis=us-gaap_RestrictedStockMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_PlanNameAxis=ctgo_The2010PlanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_TitleOfIndividualAxis=srt_ChiefExecutiveOfficerMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_VestingAxis=us-gaap_ShareBasedCompensationAwardTrancheOneMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_VestingAxis=us-gaap_ShareBasedCompensationAwardTrancheTwoMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_TitleOfIndividualAxis=srt_ChiefFinancialOfficerMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CapitalizedCostsOfUnprovedPropertiesExcludedFromAmortizationByPropertyOrProjectAxis=ctgo_TetlinLeaseMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_StatementScenarioAxis=ctgo_Scenario1Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_StatementScenarioAxis=ctgo_Scenario2Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_StatementScenarioAxis=ctgo_Scenario3Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=ctgo_TheJointVentureCompanyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CapitalizedCostsOfUnprovedPropertiesExcludedFromAmortizationByPropertyOrProjectAxis=ctgo_TetlinLeaseAndCertainOtherPropertiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_CounterpartyNameAxis=ctgo_RoyalGoldMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CapitalizedCostsOfUnprovedPropertiesExcludedFromAmortizationByPropertyOrProjectAxis=ctgo_AdditionalPropertiesMember
Namespace Prefix:
Data Type:	na
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Note 10 - Commitments and Contingencies (Details Textual) - USD ($)					1 Months Ended		12 Months Ended
	Dec. 30, 2020	Dec. 11, 2020	Jun. 10, 2020	Jul. 15, 2012	Dec. 31, 2020	Jul. 31, 2008	Jun. 30, 2021	Jun. 30, 2020	Feb. 06, 2020	Feb. 28, 2019
Contingent Salary and Compensation, Retention Agreement										$ 1,500,000
Restricted Stock [Member] \| The 2010 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period (in shares)							205,833	233,000
Chief Executive Officer [Member]
Contingent Salary and Compensation, Retention Agreement			$ 350,000						$ 1,000,000
Short Term Incentive Plan, Minimum Performance Target, Payout, Percentage of Base Salary			25.00%
Short Term Incentive Plan, All Performance Goals, Payout, Percentage of Base Salary			100.00%
Short Term Incentive Plan, Maximum Performance Target, Payout, Percentage of Base Salary			200.00%
Short Term Incentive Plan, Payout, Percentage Cash			50.00%
Short Term Incentive Plan, Payout, Percentage Restricted Stock			50.00%
Short Term Incentive Plan, Change of Control, Percentage of Base Salary			200.00%
Short Term Incentive Plan, Change of Control, Maximum Period of Payment (Day)			30 days
Short-term Incentive Plan, Compensation Expense, Cash Bonus					$ 350,000
Chief Executive Officer [Member] \| Restricted Stock [Member] \| The 2010 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period (in shares)		23,333			23,333
Chief Executive Officer [Member] \| Restricted Stock [Member] \| Share-based Payment Arrangement, Tranche One [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period (Year)			1 year
Chief Executive Officer [Member] \| Restricted Stock [Member] \| Share-based Payment Arrangement, Tranche Two [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period (Year)			2 years
Chief Financial Officer [Member]
Contingent Salary and Compensation, Retention Agreement									$ 250,000
Tetlin Lease [Member]
Inception-to-date Payments to Reduce Royalty Rate							$ 225,000
Decrease in Royalty Rates							0.75%
Tetlin Lease [Member] \| Scenario 1 [Member]
Increase in Royalty Rates							0.25%
Payment that Lessor May Pay to Lessee to Increase Royalty Rate							$ 150,000
Tetlin Lease [Member] \| Scenario 2 [Member]
Increase in Royalty Rates							0.50%
Payment that Lessor May Pay to Lessee to Increase Royalty Rate							$ 300,000
Tetlin Lease [Member] \| Scenario 3 [Member]
Increase in Royalty Rates							0.75%
Payment that Lessor May Pay to Lessee to Increase Royalty Rate	$ 450,000
Tetlin Lease [Member] \| Minimum [Member]
Advance Royalties to Be Paid Per Year				$ 75,000			$ 50,000
Tetlin Lease [Member] \| The Joint Venture Company [Member]
Initial Term of Leases and Concessions on Undeveloped Acreage (Year)						10 years
Extension of Term of Leases and Concessions on Undeveloped Acreage (Year)						10 years
Contractual Annual Exploration Costs						$ 350,000
Tetlin Lease [Member] \| The Joint Venture Company [Member] \| Minimum [Member]
Royalty Rate						3.00%	2.25%
Tetlin Lease [Member] \| The Joint Venture Company [Member] \| Maximum [Member]
Royalty Rate						5.00%	4.25%
Tetlin Lease and Certain Other Properties [Member]
Annual Claim Rentals							$ 349,955
Tetlin Lease and Certain Other Properties [Member] \| The Joint Venture Company [Member] \| Royal Gold [Member]
Overriding Royalty Interest							3.00%
Additional Properties [Member] \| The Joint Venture Company [Member] \| Royal Gold [Member]
Overriding Royalty Interest							2.00%
Net Smelter Returns Silver Royalty, Percent							28.00%
Net Smelter Returns Royalty Interest, Percent							1.00%