Debt instrument initial borrowed amount.

No definition available.

Name:	atrs_DebtInstrumentInitialBorrowedAmount
Namespace Prefix:	atrs_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Percentage of loan fee on original principal amount.

+ References

No definition available.

+ Details

Name:	atrs_PercentageOfLoanFeeOnOriginalPrincipalAmount
Namespace Prefix:	atrs_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Prepayment fee percentage on principal loan prepaid

+ References

No definition available.

+ Details

Name:	atrs_PrepaymentFeePercentageOnPrincipalLoanPrepaid
Namespace Prefix:	atrs_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Face (par) amount of debt instrument at time of issuance.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=119993939&loc=d3e28551-108399

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=114775985&loc=d3e28878-108400

+ Details

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

- Definition

Net increase or decrease in the carrying amount of the debt instrument for the period.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(f))
-URI http://asc.fasb.org/extlink&oid=120395691&loc=d3e23780-122690

+ Details

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

- Definition

Effective interest rate for the funds borrowed under the debt agreement considering interest compounding and original issue discount or premium.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 6
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=120520924&loc=SL6036836-161870

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=119993939&loc=d3e28551-108399

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(1))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

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

- Definition

Description of the payment terms of the debt instrument (for example, whether periodic payments include principal and frequency of payments) and discussion about any contingencies associated with the payment.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(3))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 470
-Section 50
-Paragraph 3
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=75038535&loc=d3e64711-112823

+ Details

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

- Definition

Amount of unused borrowing capacity under the long-term financing arrangement that is available to the entity as of the balance sheet date.

+ References

+ Details

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

- Definition

Amount after unamortized (discount) premium and debt issuance costs of long-term debt classified as noncurrent and excluding amounts to be repaid within one year or the normal operating cycle, if longer. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

+ References

+ Details

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

- Details

Name:	us-gaap_LineOfCreditFacilityAxis=atrs_HerculesCapitalIncMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=atrs_TermLoanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_TypeOfArrangementAxis=atrs_FirstAmendmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_VariableRateAxis=us-gaap_PrimeRateMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MaximumMember
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- Details

Name:	srt_RangeAxis=srt_MinimumMember
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Balance Type:
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- Details

Name:	us-gaap_DebtInstrumentAxis=atrs_TermLoanTrancheOneMember
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Balance Type:
Period Type:

- Details

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Balance Type:
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- Details

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Long-Term Debt - Additional Information (Detail) - USD ($)		12 Months Ended
	Jun. 26, 2019	Dec. 31, 2020	Dec. 31, 2019	Jun. 25, 2019	Jun. 06, 2017
Debt Instrument [Line Items]
Carrying value of long term debt		$ 24,669,000	$ 40,395,000
Hercules Capital, Inc [Member] \| Term Loan [Member]
Debt Instrument [Line Items]
Debt instrument, effective interest rate		8.50%	9.25%
Debt instrument, payment terms		Payments under the loan are interest-only until the first principal payment is due.
Carrying value of long term debt		$ 40,899,000	$ 40,395,000
Hercules Capital, Inc [Member] \| Term Loan [Member] \| First Amendment [Member]
Debt Instrument [Line Items]
Long-term debt, face amount	$ 50,000,000.0			$ 35,000,000.0
Debt instrument, payment terms		extended the interest-only payment period of the Term Loan to August 1, 2021. The interest only period may be further extended to August 1, 2022 if the Company achieves a certain loan extension milestone, requests such extension, and pays an extension fee equal to one half of one percent of the principal amount outstanding.
Hercules Capital, Inc [Member] \| Term Loan [Member] \| Prime Based Variable Rate [Member]
Debt Instrument [Line Items]
Debt Instrument, variable interest rate		9.50%
Hercules Capital, Inc [Member] \| Term Loan [Member] \| Maximum [Member]
Debt Instrument [Line Items]
Long-term debt, face amount					$ 35,000,000.0
Prepayment fee percentage on principal loan prepaid		3.00%
Hercules Capital, Inc [Member] \| Term Loan [Member] \| Minimum [Member]
Debt Instrument [Line Items]
Prepayment fee percentage on principal loan prepaid		1.00%
Hercules Capital, Inc [Member] \| Tranche I Loan [Member]
Debt Instrument [Line Items]
Long-term debt, borrowed amount					$ 25,000,000.0
Percentage of loan fee on original principal amount		4.25%
Hercules Capital, Inc [Member] \| Tranche II [Member]
Debt Instrument [Line Items]
Percentage of loan fee on original principal amount		3.95%
Hercules Capital, Inc [Member] \| Tranche II [Member] \| First Amendment [Member]
Debt Instrument [Line Items]
Long-term debt, increase in face amount	15,000,000.0
Hercules Capital, Inc [Member] \| Tranche III [Member] \| Maximum [Member] \| First Amendment [Member]
Debt Instrument [Line Items]
Debt instrument, available option to request additional advance amount	10,000,000.0
Hercules Capital, Inc [Member] \| Tranche III [Member] \| Minimum [Member] \| First Amendment [Member]
Debt Instrument [Line Items]
Debt instrument, available option to request additional advance amount	$ 5,000,000.0