Commitments and Contingencies (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2025	Mar. 31, 2024	Oct. 28, 2021
Annual increase in rent percentage	3.00%
Standby letter of credit			$ 5.0
Lease term			16 years
Allowance for tenant improvements			$ 7.2
Rent expense under operating leases	$ 2.0	$ 2.2
Variable lease payment	0.3	$ 0.6
Minimum
Annual base rent for operating lease	1.9
Maximum
Annual base rent for operating lease	2.5
Cash
Standby letter of credit	$ 0.2
Annual reduction of standby letter of credit	20.00%

Amount of allowance for tenant improvements receivable.

No definition available.

Name:	armp_AllowanceForTenantImprovementsReceivable
Namespace Prefix:	armp_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Annual increase in rent percentage.

+ References

No definition available.

+ Details

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Namespace Prefix:	armp_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Annual reduction of standby letter of credit..

+ References

No definition available.

+ Details

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Namespace Prefix:	armp_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount of annual base rent for operating lease.

+ References

No definition available.

+ Details

Name:	armp_OperatingLeaseBaseAnnual
Namespace Prefix:	armp_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Term of lessee's operating lease not yet commenced, 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 842
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478964/842-20-50-3

+ Details

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

- Definition

The total amount of the contingent obligation under letters of credit outstanding as of the reporting date.

+ References

No definition available.

+ Details

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

- Definition

Amount of operating lease expense. Excludes sublease income.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 842
-SubTopic 20
-Name Accounting Standards Codification
-Section 45
-Paragraph 4
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479041/842-20-45-4

+ Details

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

- Definition

Amount of cash outflow for variable lease payment excluded from lease liability.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 842
-SubTopic 20
-Name Accounting Standards Codification
-Section 45
-Paragraph 5
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479041/842-20-45-5

+ Details

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

- Details

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

- Details

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- Details

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Data Type:	na
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