Debt instrument, convertible, threshold percentage of outstanding debt.

No definition available.

Name:	atec_DebtInstrumentConvertibleThresholdPercentageOfOutstandingDebt
Namespace Prefix:	atec_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of debt instruments issued.

+ References

No definition available.

+ Details

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Namespace Prefix:	atec_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage of voting equity interests acquired at the acquisition date in the business combination.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=79982066&loc=d3e1392-128463

+ Details

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

- Definition

Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

+ References

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-Publisher FASB
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-Topic 470
-SubTopic 20
-Section 50
-Paragraph 4
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-URI http://asc.fasb.org/extlink&oid=120400017&loc=d3e572229-122910

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-Subparagraph (SX 210.9-03(16))
-URI http://asc.fasb.org/extlink&oid=120398452&loc=d3e534808-122878

+ Details

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

- Definition

Ratio applied to the conversion of debt instrument into equity with equity shares divided by debt principal amount.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
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+ Details

Name:	us-gaap_DebtInstrumentConvertibleConversionRatio1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	duration

- Definition

Threshold period of specified consecutive trading days within which common stock price to conversion price of convertible debt instrument must exceed threshold percentage for specified number of trading days to trigger conversion feature.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentConvertibleThresholdConsecutiveTradingDays1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Minimum percentage of common stock price to conversion price of convertible debt instruments to determine eligibility of conversion.

+ References

No definition available.

+ Details

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

- Definition

Date the debt agreement requires the first payment to be made, in CCYY-MM-DD format.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
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+ Details

Name:	us-gaap_DebtInstrumentDateOfFirstRequiredPayment1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

Description of the frequency of periodic payments (monthly, quarterly, annual).

+ References

+ Details

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

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

+ Details

Name:	us-gaap_DebtInstrumentInterestRateStatedPercentage
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

Date when the debt instrument is scheduled to be fully repaid, in CCYY-MM-DD format.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
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+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:dateItemType
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

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+ Details

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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of the cost of borrowed funds accounted for as interest expense for debt.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
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+ Details

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

- Definition

The cash inflow from the issuance of a long-term debt instrument which can be exchanged for a specified amount of another security, typically the entity's common stock, at the option of the issuer or the holder.

+ References

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+ Details

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

- Details

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Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_BusinessAcquisitionAxis=atec_OCEANEMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_ConvertibleDebtMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=atec_EOSImagingSAMember
Namespace Prefix:
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Balance Type:
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- Details

Name:	srt_RangeAxis=srt_MinimumMember
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Debt - OCEANE Convertible Bonds (Details) € in Millions, $ in Millions				3 Months Ended	6 Months Ended
	Jun. 20, 2021 Day	May 31, 2018 USD ($) ConvertibleBond	May 31, 2018 EUR (€) ConvertibleBond	Jun. 30, 2021 USD ($)	Jun. 30, 2021 USD ($)	Jun. 30, 2021 EUR (€)
EOS
Debt Instrument [Line Items]
Percentage of ownership acquired				100.00%	100.00%	100.00%
OCEANE
Debt Instrument [Line Items]
Percentage of ownership acquired				57.00%	57.00%	57.00%
OCEANE Convertible Bonds
Debt Instrument [Line Items]
Carrying value of OCEANEs				$ 15.1	$ 15.1	€ 12.6
OCEANE Convertible Bonds \| EOS
Debt Instrument [Line Items]
Number of OCEANE convertible bonds issued \| ConvertibleBond		4,344,651	4,344,651
Aggregate gross proceeds		$ 34.3	€ 29.5
Interest rate		6.00%	6.00%
Payment terms					The OCEANEs are unsecured obligations of EOS, rank equally with all other unsecured and unsubordinated obligations of EOS, and pay interest at a rate equal to 6% per year, payable semiannually in arrears on May 31 and November 30 of each year, beginning November 30, 2018
Debt instrument, frequency of periodic payment		semiannually	semiannually
Debt instrument, Date of first payment		Nov. 30, 2018	Nov. 30, 2018
Debt instrument, maturity date		May 31, 2023	May 31, 2023
Interest expense \| $				$ 0.1	$ 0.1
Initial conversion rate		1	1
Threshold percentage of par value trigger	150.00%
Consecutive trading days	40
Threshold percentage of debt instrument outstanding	15.00%
OCEANE Convertible Bonds \| EOS \| Minimum [Member]
Debt Instrument [Line Items]
Consecutive trading days	20