Contract Assets and Contract Liabilities - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2026	Sep. 30, 2026
Contract with Customer, Contract Asset, Contract Liability, and Receivable [Abstract]
Revenue recognized from contract liabilities	$ 0.8	$ 8.2

Contract with customer liability revenue recognized including opening balance.

No definition available.

Name:	atec_ContractWithCustomerLiabilityRevenueRecognizedIncludingOpeningBalance
Namespace Prefix:	atec_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration