Leases - Lease Cost (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2026	Sep. 30, 2025	Sep. 30, 2026	Sep. 30, 2025
Lease cost
Total operating lease cost	$ 2,516	$ 2,420	$ 7,615	$ 7,501
Depreciation of leased assets	318	264	956	907
Total finance lease cost	1,418	1,403	4,286	4,350
Total lease cost	3,934	3,823	11,901	11,851
Short-term lease and variable lease costs	500	400	1,500	1,400
Location, Statement of Income, Balance [Axis]: us-gaap:CostOfGoodsAndServicesSold
Lease cost
Total operating lease cost	1,626	1,626	4,865	4,907
Location, Statement of Income, Balance [Axis]: us-gaap:GeneralAndAdministrativeExpense
Lease cost
Total operating lease cost	268	249	701	787
Location, Statement of Income, Balance [Axis]: us-gaap:InterestExpenseNonoperating
Lease cost
Interest on lease liabilities	1,100	1,139	3,330	3,443
Location, Statement of Income, Balance [Axis]: us-gaap:ResearchAndDevelopmentExpense
Lease cost
Total operating lease cost	110	109	502	477
Location, Statement of Income, Balance [Axis]: us-gaap:SellingAndMarketingExpense
Lease cost
Total operating lease cost	$ 512	$ 436	$ 1,547	$ 1,330

Amount of finance lease cost recognized by lessee for lease contract.

No definition available.

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Namespace Prefix:	acls_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of short-term and variable lease cost.

+ References

No definition available.

+ Details

Name:	acls_ShortTermAndVariableLeaseCost
Namespace Prefix:	acls_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of interest expense on finance lease liability.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 842
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 53
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479589/842-20-55-53

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 842
-SubTopic 20
-Name Accounting Standards Codification
-Section 45
-Paragraph 4
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479041/842-20-45-4

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 842
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 4
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478964/842-20-50-4

+ Details

Name:	us-gaap_FinanceLeaseInterestExpense
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of amortization expense attributable to right-of-use asset from finance lease.

+ References

+ Details

Name:	us-gaap_FinanceLeaseRightOfUseAssetAmortization
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of lease cost recognized by lessee for lease contract.

+ References

+ Details

Name:	us-gaap_LeaseCost
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- References

No definition available.

+ Details

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

- Definition

Amount of single lease cost, calculated by allocation of remaining cost of lease over remaining lease term. Includes, but is not limited to, single lease cost, after impairment of right-of-use asset, calculated by amortization of remaining right-of-use asset and accretion of lease liability.

+ References

+ Details

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

- Details

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Namespace Prefix:
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Balance Type:
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- Details

Name:	us-gaap_StatementOfIncomeLocationBalanceAxis=us-gaap_GeneralAndAdministrativeExpense
Namespace Prefix:
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- Details

Name:	us-gaap_StatementOfIncomeLocationBalanceAxis=us-gaap_InterestExpenseNonoperating
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- Details

Name:	us-gaap_StatementOfIncomeLocationBalanceAxis=us-gaap_ResearchAndDevelopmentExpense
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- Details

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