American Depositary Shares, Option Price Per Share

No definition available.

Name:	avdl_AmericanDepositarySharesOptionPricePerShare
Namespace Prefix:	avdl_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant

- Definition

American Depositary Shares, Premium Percentage

+ References

No definition available.

+ Details

Name:	avdl_AmericanDepositarySharesPremiumPercentage
Namespace Prefix:	avdl_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

American Depositary Shares Purchased, Price Per Share

+ References

No definition available.

+ Details

Name:	avdl_AmericanDepositarySharesPurchasedPricePerShare
Namespace Prefix:	avdl_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant

- Definition

American Depository Shares, Conversion Ratio

+ References

No definition available.

+ Details

Name:	avdl_AmericanDepositorySharesConversionRatio
Namespace Prefix:	avdl_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	duration

- Definition

Coupon Interest Expense

+ References

No definition available.

+ Details

Name:	avdl_CouponInterestExpense
Namespace Prefix:	avdl_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Debt Instrument, Convertible, Business Day Period During Which Debt Can Be Converted

+ References

No definition available.

+ Details

Name:	avdl_DebtInstrumentConvertibleBusinessDayPeriodDuringWhichDebtCanBeConverted
Namespace Prefix:	avdl_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Debt Instrument, Convertible, Percentage of Product Of The Last Reported Sale Price Of The American Depositary Shares And The Exchange Rate On Each Such Trading Day

+ References

No definition available.

+ Details

Name:	avdl_DebtInstrumentConvertiblePercentageOfProductOfTheLastReportedSalePriceOfTheAmericanDepositarySharesAndTheExchangeRateOnEachSuchTradingDay
Namespace Prefix:	avdl_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Debt Instrument, Convertible, Scheduled Threshold Trading Days

+ References

No definition available.

+ Details

Name:	avdl_DebtInstrumentConvertibleScheduledThresholdTradingDays
Namespace Prefix:	avdl_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Debt Instrument, Convertible, Threshold Consecutive Business Days

+ References

No definition available.

+ Details

Name:	avdl_DebtInstrumentConvertibleThresholdConsecutiveBusinessDays
Namespace Prefix:	avdl_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Debt Instrument, Option To Purchase Aggregate Principal Amount, Term

+ References

No definition available.

+ Details

Name:	avdl_DebtInstrumentOptionToPurchaseAggregatePrincipalAmountTerm
Namespace Prefix:	avdl_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Debt Instrument, Option to Increase Face Amount

+ References

No definition available.

+ Details

Name:	avdl_DebtInstrumentOptiontoIncreaseFaceAmount
Namespace Prefix:	avdl_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of amortization expense attributable to debt discount (premium) and debt issuance costs.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3602-108585

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=119993939&loc=d3e28555-108399

+ Details

Name:	us-gaap_AmortizationOfFinancingCostsAndDiscounts
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
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

Threshold number of specified trading days that common stock price to conversion price of convertible debt instruments must exceed threshold percentage within a specified consecutive trading period to trigger conversion feature.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentConvertibleThresholdTradingDays
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
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

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

+ 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)(1))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

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

- Definition

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

+ 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 (b)
-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 220
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.8)
-URI http://asc.fasb.org/extlink&oid=120395209&loc=SL114868664-224227

+ Details

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

- Definition

Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (b)(3)
-URI http://asc.fasb.org/extlink&oid=120520924&loc=SL6031897-161870

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(16))
-URI http://asc.fasb.org/extlink&oid=120400017&loc=d3e572229-122910

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(16))
-URI http://asc.fasb.org/extlink&oid=120398452&loc=d3e534808-122878

Reference 4: 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))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

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

- Definition

The cash outflow paid to third parties in connection with debt origination, which will be amortized over the remaining maturity period of the associated long-term debt.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 15
-Subparagraph (e)
-URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3291-108585

+ Details

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

- Definition

The cash inflow from a debt initially having maturity due after one year or beyond the operating cycle, if longer.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 14
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3255-108585

+ Details

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

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

- Definition

Total of all stockholders' equity (deficit) items, net of receivables from officers, directors, owners, and affiliates of the entity which are attributable to the parent. The amount of the economic entity's stockholders' equity attributable to the parent excludes the amount of stockholders' equity which is allocable to that ownership interest in subsidiary equity which is not attributable to the parent (noncontrolling interest, minority interest). This excludes temporary equity and is sometimes called permanent equity.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(g)(1)(ii))
-URI http://asc.fasb.org/extlink&oid=120395691&loc=d3e23780-122690

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SAB Topic 4.E)
-URI http://asc.fasb.org/extlink&oid=27010918&loc=d3e74512-122707

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(31))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

Reference 4: 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(29))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

Reference 5: 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(30))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

Reference 6: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 28
-Subparagraph (f)
-URI http://asc.fasb.org/extlink&oid=75031198&loc=d3e14064-108612

Reference 7: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 323
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=114001798&loc=d3e33918-111571

+ Details

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

- Details

Name:	us-gaap_StatementEquityComponentsAxis=us-gaap_AdditionalPaidInCapitalMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementEquityComponentsAxis=us-gaap_RetainedEarningsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_CumulativeEffectPeriodOfAdoptionAxis=srt_CumulativeEffectPeriodOfAdoptionAdjustmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

Name:	us-gaap_DebtInstrumentAxis=avdl_A450PercentExchangeableSeniorNotesDue2023Member
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_DebtInstrumentRedemptionPeriodAxis=us-gaap_DebtInstrumentRedemptionPeriodOneMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentRedemptionPeriodAxis=us-gaap_DebtInstrumentRedemptionPeriodTwoMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentRedemptionPeriodAxis=us-gaap_DebtInstrumentRedemptionPeriodThreeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Long-Term Debt - Narrative (Details) $ / shares in Units, $ in Thousands		3 Months Ended
	Feb. 16, 2018 USD ($) day $ / shares Rate	Mar. 31, 2021 USD ($)	Mar. 31, 2020 USD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)
Schedule of Capitalization, Long-term Debt [Line Items]
Interest expense, debt		$ 1,929	$ 3,190
Amortization of debt discount and debt issuance costs		312	1,573
Stockholders' equity		136,504	32,067	$ 162,266	$ (29,199)
ADSs, conversion ratio \| Rate	9269.56%
Additional paid-in capital
Schedule of Capitalization, Long-term Debt [Line Items]
Stockholders' equity		542,093	497,249	566,916	434,391
Accumulated deficit
Schedule of Capitalization, Long-term Debt [Line Items]
Stockholders' equity		(383,872)	(392,080)	(384,187)	$ (391,215)
Cumulative Effect, Period of Adoption, Adjustment
Schedule of Capitalization, Long-term Debt [Line Items]
Book value of long-term debt				12,939
Stockholders' equity				(12,939)
Cumulative Effect, Period of Adoption, Adjustment \| Additional paid-in capital
Schedule of Capitalization, Long-term Debt [Line Items]
Stockholders' equity				(26,699)
Cumulative Effect, Period of Adoption, Adjustment \| Accumulated deficit
Schedule of Capitalization, Long-term Debt [Line Items]
Stockholders' equity				13,760
Senior Notes
Schedule of Capitalization, Long-term Debt [Line Items]
Book value of long-term debt		141,461		$ 128,210
4.50% Exchangeable Senior Notes Due 2023 \| Convertible Debt
Schedule of Capitalization, Long-term Debt [Line Items]
Debt instrument, face amount	$ 125,000
Debt instrument, interest rate, stated percentage	4.50%
Option to purchase aggregate principal amount, term	30 days
Option to increase aggregate principal amount	$ 18,750
Payments of debt issuance costs	6,190
Proceeds from loans or conditional grants	$ 137,560
ADS, option price per share (in dollars per share) \| $ / shares	$ 10.79
ADS premium percentage	20.00%
ADS purchased, price per share (in dollars per share) \| $ / shares	$ 8.99
4.50% Exchangeable Senior Notes Due 2023 \| Senior Notes
Schedule of Capitalization, Long-term Debt [Line Items]
Interest expense, debt		1,929	3,190
Coupon interest expense		1,617	1,617
Amortization of debt discount and debt issuance costs		$ 312	$ 1,573
Debt instrument, interest rate, stated percentage		4.50%		4.50%
Debt Instrument, Redemption, Period One \| 4.50% Exchangeable Senior Notes Due 2023 \| Convertible Debt
Schedule of Capitalization, Long-term Debt [Line Items]
Number of business days	5 days
Consecutive business days	5 days
Percentage of product of the last reported sale price of the American Depositary Shares and the exchange rate on each such trading day	98.00%
Debt Instrument, Redemption, Period Two \| 4.50% Exchangeable Senior Notes Due 2023 \| Convertible Debt
Schedule of Capitalization, Long-term Debt [Line Items]
Scheduled threshold trading days	35 days
Threshold trading days \| day	95
Debt Instrument, Redemption, Period Three \| 4.50% Exchangeable Senior Notes Due 2023 \| Convertible Debt
Schedule of Capitalization, Long-term Debt [Line Items]
Threshold trading days \| day	20
Consecutive trading days \| day	30
Threshold percentage of stock price trigger	130.00%