WARRANTS (Details)	12 Months Ended
Jun. 30, 2025 D $ / shares shares	Jun. 30, 2024 $ / shares shares
WARRANTS
Price of the entity's common stock (in dollars per share)	$ 990
Issue price per share (in dollars per share)	$ 552
Equity proceeds	60.00%
Trading days for determining volume weighted average price \| D	20
Exercise price per share (in dollars per share)	$ 570
Warrant percentage	115.00%
Market value percentage	165.00%
Public Warrants
WARRANTS
Public warrants outstanding (in shares) \| shares	20,125,000	20,125,000
Number of shares called by each warrant \| shares	0.5	0.5
Number of days within which the registration statement should be declared effective	120 days
Expire term	5 years
Redemption price per warrant (in dollars per share)	$ 0.6
Notice period redemption	30 days
Price of the entity's common stock (in dollars per share)	$ 990
Threshold number of specified trading days \| D	20
Threshold consecutive number of specified trading days \| D	30
Public Warrants \| Post Reverse Split
WARRANTS
Warrant exercise price (in dollars per share)	$ 690	$ 690
Private Warrants
WARRANTS
Public warrants outstanding (in shares) \| shares	6,153,125	6,153,125
Number of shares called by each warrant \| shares	1
Private Warrants \| Post Reverse Split
WARRANTS
Warrant exercise price (in dollars per share)	$ 690

Maximum number of days within which a written notice is to be provided for redemption of warrants.

No definition available.

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- Definition

Price of the entity's common stock which would be required to be attained for redemption of warrants.

+ References

No definition available.

+ Details

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- Definition

Threshold consecutive number of specified trading days over which the stock price is considered for redemption of warrants.

+ References

No definition available.

+ Details

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- Definition

Threshold number of specified trading days over which the stock price is considered for redemption of warrants.

+ References

No definition available.

+ Details

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Data Type:	xbrli:integerItemType
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- Definition

Issue price per share.

+ References

No definition available.

+ Details

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Namespace Prefix:	atch_
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Period Type:	duration

- Definition

Market Value Percentage

+ References

No definition available.

+ Details

Name:	atch_MarketValuePercentage
Namespace Prefix:	atch_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of days within which the registration statement filed with SEC should be declared effective.

+ References

No definition available.

+ Details

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Namespace Prefix:	atch_
Data Type:	xbrli:durationItemType
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- Definition

Proceeds From Other Equity Percentage.

+ References

No definition available.

+ Details

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Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

The price per share at which the warrants shall be redeemed by the company.

+ References

No definition available.

+ Details

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Namespace Prefix:	atch_
Data Type:	dtr-types:perShareItemType
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Period Type:	instant

- Definition

Threshold trading days for determining volume weighted average price prior to business combination.

+ References

No definition available.

+ Details

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Namespace Prefix:	atch_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- References

No definition available.

+ Details

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Data Type:	xbrli:stringItemType
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Period Type:	duration

- Definition

Warrant Percentage.

+ References

No definition available.

+ Details

Name:	atch_WarrantPercentage
Namespace Prefix:	atch_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Exercise price per share or per unit of warrants or rights outstanding.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 235
-SubTopic 10
-Name Accounting Standards Codification
-Section S50
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480738/235-10-S50-1

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 235
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(h)(4))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480678/235-10-S99-1

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481112/505-10-50-3

+ Details

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Period Type:	instant

- Definition

Number of securities into which each warrant or right may be converted. For example, but not limited to, each warrant may be converted into two shares.

+ References

No definition available.

+ Details

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Period Type:	instant

- Definition

Number of warrants or rights outstanding.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

Weighted average price at which option holders acquired shares when converting their stock options into shares.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(iv)(02)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480429/718-10-50-2

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Data Type:	dtr-types:perShareItemType
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- Definition

Period between issuance and expiration of outstanding warrant and right embodying unconditional obligation requiring redemption by transferring asset at specified or determinable date or upon event certain to occur, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (bbb)(2)(i)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482106/820-10-50-2

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (bbb)(2)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482106/820-10-50-2

Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (bbb)(1)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482106/820-10-50-2

+ Details

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- Details

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- Details

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- Details

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