Note 14 - Commitments and Contingencies (Details Textual) - USD ($) $ in Thousands		3 Months Ended
Jan. 01, 2023	Mar. 31, 2023	Mar. 31, 2022
Lessee, Operating Lease, Monthly Rent Payments	$ 2
Operating Lease, Expense		$ 4	$ 8
Research and Development Arrangement [Member]
Unrecorded Unconditional Purchase Obligation, to be Paid, Remainder of Fiscal Year		1,146
Unrecorded Unconditional Purchase Obligation, to be Paid, Year One		13
Unrecorded Unconditional Purchase Obligation, Purchases Incurred		$ 111

Represents the monthly payments by lessee in operating lease.

No definition available.

Name:	atos_LesseeOperatingLeaseMonthlyRentPayments
Namespace Prefix:	atos_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The amount purchased as of the balance sheet date under an unrecorded unconditional purchase obligation (for example, under the take-or-pay or throughput contract).

+ References

No definition available.

+ Details

Name:	atos_UnrecordedUnconditionalPurchaseObligationPurchasesIncurred
Namespace Prefix:	atos_
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 fixed and determinable portion of unrecorded unconditional purchase obligation to be paid in next fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 440
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 4
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482648/440-10-50-4

+ Details

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

- Definition

Amount of fixed and determinable portion of unrecorded unconditional purchase obligation to be paid in remainder of current fiscal year.

+ References

No definition available.

+ Details

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

- Details

Name:	us-gaap_UnrecordedUnconditionalPurchaseObligationByCategoryOfItemPurchasedAxis=us-gaap_ResearchAndDevelopmentArrangementMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: