The minimum amount the entity agreed to spend under the long-term purchase commitment.

No definition available.

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- Definition

Term of long-term purchase commitment extension, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

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- Definition

Number of options to extend the term of the long-term purchase commitment.

+ References

No definition available.

+ Details

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Namespace Prefix:	cthr_
Data Type:	xbrli:integerItemType
Balance Type:	na
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- Definition

Amount of purchases made under the long-term purchase commitment.

+ References

No definition available.

+ Details

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Namespace Prefix:	cthr_
Data Type:	xbrli:monetaryItemType
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- Definition

The remaining minimum amount the entity agreed to spend under the long-term purchase commitment.

+ References

No definition available.

+ Details

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Namespace Prefix:	cthr_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Percentage of required SiC materials committed to be purchased.

+ References

No definition available.

+ Details

Name:	cthr_PercentageOfMaterialsCommittedToBePurchased
Namespace Prefix:	cthr_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount awarded to other party in judgment or settlement of litigation.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- References

No definition available.

+ Details

Name:	us-gaap_LongTermCommitmentExcludingUnconditionalPurchaseObligationAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of loss contingency liability.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 450
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483076/450-20-50-1

Reference 2: http://www.xbrl.org/2003/role/recommendedDisclosureRef
-Topic 450
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 10
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483076/450-20-50-10

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of cash outflow reducing loss contingency liability.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 450
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483076/450-20-50-1

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The amount of cash paid for the settlement of litigation or for other legal issues during the period.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Section 45
-Paragraph 25
-Subparagraph (g)
-SubTopic 10
-Topic 230
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482740/230-10-45-25

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Minimum amount of purchase arrangement in which the entity has agreed to expend funds to procure goods or services from a supplier.

+ References

No definition available.

+ Details

Name:	us-gaap_PurchaseObligation
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

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- Details

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Balance Type:
Period Type:

- Details

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Data Type:	na
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- Details

Name:	srt_RangeAxis=srt_MinimumMember
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COMMITMENTS AND CONTINGENCIES, Purchase Commitments (Details)						3 Months Ended
	Dec. 31, 2025 USD ($)	Feb. 28, 2025 USD ($)	Feb. 26, 2025 USD ($)	Feb. 11, 2025 USD ($)	Feb. 10, 2025 USD ($)	Sep. 30, 2024 USD ($) Option	Sep. 30, 2023 USD ($)
Supply Agreement with Wolfspeed [Member]
Purchase Commitments [Abstract]
Accrued arbitration award						$ 4,770,000
Supply Agreement with Wolfspeed [Member] \| Plan [Member]
Purchase Commitments [Abstract]
Settlement amount to be paid	$ 2,440,000	$ 1,830,000		$ 500,000
Supply Agreement with Wolfspeed [Member] \| Subsequent Event [Member]
Purchase Commitments [Abstract]
Amount payable under settlement agreement					$ 4,770,000
Payments made			$ 1,830,000		$ 500,000
SiC Materials [Member]
Purchase Commitments [Abstract]
Percentage of materials committed to be purchased						100.00%
Number of options to extend term of exclusive supply agreement \| Option						1
Extension period of exclusive supply agreement						2 years
Total purchase commitment						$ 52,950,000
Remaining purchase commitment						24,750,000
Purchases						0	$ 0
SiC Materials [Member] \| Minimum [Member]
Purchase Commitments [Abstract]
Minimum annual purchase commitments						4,000,000
SiC Materials [Member] \| Maximum [Member]
Purchase Commitments [Abstract]
Minimum annual purchase commitments						$ 10,000,000