COMMITMENTS AND CONTINGENCIES, Purchase Commitments (Details) - SiC Materials [Member] $ in Thousands	3 Months Ended
Sep. 30, 2021 USD ($) Option	Sep. 30, 2020 USD ($)
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
Remaining purchase commitment	31,350
Purchases	1,500	$ 0
Minimum [Member]
Purchase Commitments [Abstract]
Future minimum annual purchase commitments	4,000
Maximum [Member]
Purchase Commitments [Abstract]
Future minimum annual purchase commitments	$ 10,000

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

No definition available.

Name:	cthr_LongTermPurchaseCommitmentCommittedAmount
Namespace Prefix:	cthr_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- 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

Name:	cthr_LongTermPurchaseCommitmentExtensionTerm
Namespace Prefix:	cthr_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

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

+ References

No definition available.

+ Details

Name:	cthr_LongTermPurchaseCommitmentNumberOfOptionsToExtendTerm
Namespace Prefix:	cthr_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

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

+ References

No definition available.

+ Details

Name:	cthr_LongTermPurchaseCommitmentPurchases
Namespace Prefix:	cthr_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

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

+ References

No definition available.

+ Details

Name:	cthr_LongTermPurchaseCommitmentRemainingCommittedAmount
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

- References

No definition available.

+ Details

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

Name:	us-gaap_LongTermPurchaseCommitmentByCategoryOfItemPurchasedAxis=cthr_SicMaterialsMember
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:	srt_RangeAxis=srt_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: