Commitments and Contingencies (Narrative) (Details) - USD ($)	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017
AmpliPhi Biosciences Corporation [Member]
Rent expense under operating leases	$ 210,000	$ 208,000
Minimum payment commitment	$ 293,000
AmpliPhi Biosciences Corporation [Member] \| Virginia Biotech Research Partnership Laboratory [Member]
Lease expiration date	Aug. 01, 2019
AmpliPhi Biosciences Corporation [Member] \| Savills Studley San Diego Office Space [Member]
Monthly rental expense	$ 5,000
AmpliPhi Biosciences Corporation [Member] \| Ljubljana Dobrunje [Member]
Lease expiration date	Feb. 01, 2023
AmpliPhi Biosciences Corporation [Member] \| Brookville Australia Lab Space [Member]
Monthly rental expense	$ 4,000
C3J [Member]
Rent expense under operating leases	1,403,000	$ 1,368,000
Minimum payment commitment	$ 4,773,000

Amount of monthly rent expense incurred for leased assets, including but not limited to, furniture and equipment, that is not directly or indirectly associated with the manufacture, sale or creation of a product or product line.

No definition available.

+ Details

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

- Definition

Date which lease or group of leases is set to expire, in CCYY-MM-DD format.

+ References

No definition available.

+ Details

Name:	us-gaap_LeaseExpirationDate1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of lessee's undiscounted obligation for lease payments for operating lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 50
-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=77888426&loc=SL77918701-209980

+ Details

Name:	us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue
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
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 45
-Paragraph 4
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=77888419&loc=SL77918638-209977

+ Details

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

- Details

Name:	dei_LegalEntityAxis=armp_AmpliphiBiosciencesCorporationMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=armp_VirginiaBiotechResearchPartnershipLaboratoryMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=armp_SavillsStudleySanDiegoOfficeSpaceMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=armp_LjubljanaDobrunjeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=armp_BrookvilleAustraliaLabSpaceMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=armp_C3jTherapeuticsIncMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: