Name:	elgx_DebtCovenantMinimumGlobalLiquidityRequirement
Namespace Prefix:	elgx_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Debt Due Rate

+ References

No definition available.

+ Details

Name:	elgx_DebtDueRate
Namespace Prefix:	elgx_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Debt Instrument, Commitment Reduction

+ References

No definition available.

+ Details

Name:	elgx_DebtInstrumentCommitmentReduction
Namespace Prefix:	elgx_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Debt Instrument, Conversion Price, Equity Offering Price

+ References

No definition available.

+ Details

Name:	elgx_DebtInstrumentConversionPriceEquityOfferingPrice
Namespace Prefix:	elgx_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Debt Instrument, Mandatory Conversion

+ References

No definition available.

+ Details

Name:	elgx_DebtInstrumentMandatoryConversion
Namespace Prefix:	elgx_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Debt Instrument, Voluntary Conversion Amount

+ References

No definition available.

+ Details

Name:	elgx_DebtInstrumentVoluntaryConversionAmount
Namespace Prefix:	elgx_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Debt Restructuring Fee, Common Shares Issued

+ References

No definition available.

+ Details

Name:	elgx_DebtRestructuringFeeCommonSharesIssued
Namespace Prefix:	elgx_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

Debt Restructuring Fee, Preferred Shares Issued

+ References

No definition available.

+ Details

Name:	elgx_DebtRestructuringFeePreferredSharesIssued
Namespace Prefix:	elgx_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

Debt Restructuring Fee, Value of Shares Issued

+ References

No definition available.

+ Details

Name:	elgx_DebtRestructuringFeeValueofSharesIssued
Namespace Prefix:	elgx_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Derivative Liabilities Removal

+ References

No definition available.

+ Details

Name:	elgx_DerivativeLiabilitiesRemoval
Namespace Prefix:	elgx_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Interest Rate, Payable in Kind

+ References

No definition available.

+ Details

Name:	elgx_InterestRatePayableinKind
Namespace Prefix:	elgx_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Maximum Equity Owned by Investor

+ References

No definition available.

+ Details

Name:	elgx_MaximumEquityOwnedbyInvestor
Namespace Prefix:	elgx_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Volume Weighted Average Price Rate

+ References

No definition available.

+ Details

Name:	elgx_VolumeWeightedAveragePriceRate
Namespace Prefix:	elgx_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Waterfall Loans Due

+ References

No definition available.

+ Details

Name:	elgx_WaterfallLoansDue
Namespace Prefix:	elgx_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Price of the entity's common stock which would be required to be attained for the conversion feature embedded in the debt instrument to become effective.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentConvertibleStockPriceTrigger
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
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

Amount of the fee that accompanies borrowing money under the debt instrument.

+ References

+ Details

Name:	us-gaap_DebtInstrumentFeeAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- 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

Amount of issuance costs recognized in a share-lending arrangement entered into by the entity, in contemplation of a convertible debt offering or other financing, before deduction of accumulated amortization or effects of subsequent adjustments.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 2A
-Subparagraph (f)
-URI http://asc.fasb.org/extlink&oid=7656903&loc=SL6757479-112611

+ Details

Name:	us-gaap_DeferredFinanceCostsOwnshareLendingArrangementIssuanceCostsGross
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of expense (income) related to adjustment to fair value of warrant liability.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-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://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 480
-SubTopic 10
-Section 25
-Paragraph 13
-URI http://asc.fasb.org/extlink&oid=109262497&loc=d3e20148-110875

+ Details

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

- Definition

Difference between the fair value of payments made and the carrying amount of debt which is extinguished prior to maturity.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 50
-Section 40
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=117329964&loc=d3e12355-112629

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 50
-Section 40
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=117329964&loc=d3e12317-112629

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-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

+ Details

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

- 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 of increase (decrease) of the credit facility.

+ 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

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

- Definition

Face amount or stated value per share of preferred stock nonredeemable or redeemable solely at the option of the issuer.

+ References

+ Details

Name:	us-gaap_PreferredStockParOrStatedValuePerShare
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant

- Definition

The maximum number of nonredeemable preferred shares (or preferred stock redeemable solely at the option of the issuer) permitted to be issued by an entity's charter and bylaws.

+ References

+ Details

Name:	us-gaap_PreferredStockSharesAuthorized
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

Cash received on stock transaction after deduction of issuance costs.

+ References

No definition available.

+ Details

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

- Definition

The number of shares issued or sold by the subsidiary or equity method investee per stock transaction.

+ References

No definition available.

+ Details

Name:	us-gaap_SaleOfStockNumberOfSharesIssuedInTransaction
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

Per share amount received by subsidiary or equity investee for each share of common stock issued or sold in the stock transaction.

+ References

No definition available.

+ Details

Name:	us-gaap_SaleOfStockPricePerShare
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant

- Definition

The maximum number of shares that the issuer could be required to issue to redeem the instrument, if applicable.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 480
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=109262807&loc=d3e22047-110879

+ Details

Name:	us-gaap_SharesSubjectToMandatoryRedemptionSettlementTermsMaximumNumberOfShares
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

Reflects the total carrying amount as of the balance sheet date of debt having initial terms less than one year or the normal operating cycle, if longer.

+ 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(19)(a))
-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 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(16)(a)(1))
-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(13))
-URI http://asc.fasb.org/extlink&oid=120398452&loc=d3e534808-122878

+ Details

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

- Definition

Ratio applied to the conversion of stock split, for example but not limited to, one share converted to two or two shares converted to one.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 4
-Subparagraph (SAB TOPIC 4.C)
-URI http://asc.fasb.org/extlink&oid=120397183&loc=d3e187143-122770

+ Details

Name:	us-gaap_StockholdersEquityNoteStockSplitConversionRatio1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_StatementClassOfStockAxis=us-gaap_ConvertiblePreferredStockMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

Name:	srt_RangeAxis=srt_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CreditFacilityAxis=us-gaap_RevolvingCreditFacilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementClassOfStockAxis=elgx_SeriesDF1PreferredStockMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CreditFacilityAxis=elgx_AmendedFirstOutWaterfallNotesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

Name:	us-gaap_DebtInstrumentAxis=elgx_FacilityAgreementDue2023Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

Name:	us-gaap_DebtInstrumentAxis=elgx_ConvertibleSeniorNotesDue2020Member
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_DebtInstrumentAxis=elgx_AmendedandRestatedFacilityAgreementMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

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

- Details

Name:	us-gaap_SubsequentEventTypeAxis=us-gaap_SubsequentEventMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

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

- Details

Name:	us-gaap_DebtInstrumentAxis=elgx_ConvertibleSeniorNotesDue2024Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

Name:	srt_RangeAxis=srt_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

Credit Facilities (Deerfield Facility Agreement, as Amended) (Details)						3 Months Ended		6 Months Ended
	Feb. 24, 2020 USD ($) $ / shares shares	Apr. 03, 2019 USD ($) $ / shares shares	Apr. 01, 2019 USD ($) day $ / shares shares	Mar. 31, 2019 USD ($)	Aug. 09, 2018 USD ($)	Jun. 30, 2020 USD ($) $ / shares shares	Jun. 30, 2019 USD ($)	Jun. 30, 2020 USD ($) $ / shares shares	Jun. 30, 2019 USD ($)	Jul. 01, 2021	Mar. 04, 2020 USD ($) shares	Dec. 31, 2018	Apr. 03, 2017 USD ($)	Nov. 02, 2015 USD ($)
Debt Instrument [Line Items]
Stock trigger price (usd per share) \| $ / shares		$ 6.61
Number of shares issued \| shares		7,889,552
Sale of stock price per share (usd per share) \| $ / shares		$ 6.61
Consideration received on transaction		$ 52,150,000
Maximum equity owned by Investor						9.50%		9.50%
Loss on debt extinguishment						$ 0	$ 11,756,000	$ 730,000	$ 11,756,000
Convertible preferred stock
Debt Instrument [Line Items]
Convertible preferred stock authorized (in shares) \| shares						1,150,000		1,150,000
Convertible preferred stock par value (in dollars per share) \| $ / shares						$ 0.001		$ 0.001
Deerfield ELGX Revolver, LLC
Debt Instrument [Line Items]
Stock trigger price (usd per share) \| $ / shares			$ 6.625
Mandatory conversion of shares			$ 1,666,666
Line of credit facility increase (decrease)					$ 5,000,000.0
Exit fee upon termination			6,100,000		11,100,000
Commitment reduction			10,000,000
Maximum equity owned by Investor						4.985%		4.985%
Deerfield ELGX Revolver, LLC \| Maximum
Debt Instrument [Line Items]
Mandatory conversion of shares			$ 25,000,000.0
Revolving loan facility
Debt Instrument [Line Items]
Debt instrument, stated interest rate							5.50%		5.50%
Loss on debt extinguishment								$ 3,400,000
Deferred financing cost						$ 400,000		$ 400,000
Revolving loan facility \| Series DF-1 Preferred Stock
Debt Instrument [Line Items]
Convertible preferred stock authorized (in shares) \| shares											5,000,000
Revolving loan facility \| Deerfield ELGX Revolver, LLC
Debt Instrument [Line Items]
Debt instrument face amount				$ 120,000,000.0
Global liquidity requirement				$ 17,500,000	22,500,000
Waterfall loans due				16.67%								33.33%
Remainder of the first out water fall loans				50.00%
Amended First Out Waterfall Notes
Debt Instrument [Line Items]
Value of shares issued	$ 2,000,000.0
Common shares issued (in shares) \| shares	950,000
Preferred shares issued (in shares) \| shares	14,649
Amended First Out Waterfall Notes \| Series DF-1 Preferred Stock
Debt Instrument [Line Items]
Conversion ratio								100
Convertible preferred stock authorized (in shares) \| shares											1,150,000
First Out Waterfall Notes
Debt Instrument [Line Items]
Conversion of debt to equity								$ 500,000
Derivative liabilities removal								$ 1,400,000
Facility Agreement, Due 2023 \| Term loan facility
Debt Instrument [Line Items]
Debt instrument face amount													$ 120,000,000.0
Amortization payments, rate													33.33%
Convertible Senior Notes Due 2020
Debt Instrument [Line Items]
Debt instrument face amount					$ 40,500,000
Debt instrument, stated interest rate					3.25%
Convertible Senior Notes Due 2020 \| Convertible notes
Debt Instrument [Line Items]
Debt instrument face amount														$ 125,000,000.0
Debt instrument, stated interest rate														3.25%
Amended and Restated Facility Agreement \| Revolving loan facility
Debt Instrument [Line Items]
Debt instrument face amount					$ 40,500,000
Amortization payments, rate					50.00%
Fixed Price Conversion \| Deerfield ELGX Revolver, LLC
Debt Instrument [Line Items]
VWAP days \| day			5
Fourth Facility Amendment
Debt Instrument [Line Items]
Debt instrument face amount	$ 40,000,000.0
Debt instrument, voluntary conversion amount	$ 3,500,000
Volume weighted average price rate trigger	85.00%
Fixed conversion price	170.00%
Convertible preferred stock par value (in dollars per share) \| $ / shares	$ 0.001
Fourth Facility Amendment \| First Out Waterfall Notes \| Revolving loan facility \| Deerfield ELGX Revolver, LLC \| Subsequent Event
Debt Instrument [Line Items]
Percentage of debt due										16.67%
Discretionary Conversion \| Amended First Out Waterfall Notes
Debt Instrument [Line Items]
Debt instrument, voluntary conversion amount											$ 60,000,000.0
Volume weighted average price rate trigger											85.00%
Fixed conversion price	200.00%
Second Amendment to Facility Agreement \| Term loan facility \| Deerfield ELGX Revolver, LLC
Debt Instrument [Line Items]
Maximum number of shares under mandatory redemption \| shares			1,430,001
Convertible Senior Notes Due 2024 \| Convertible notes
Debt Instrument [Line Items]
Debt instrument, stated interest rate						5.00%		5.00%
Interest rate, payable in kind						4.75%		4.75%
Term Loan \| Term loan facility
Debt Instrument [Line Items]
Deferred financing cost						$ 2,100,000		$ 2,100,000
Term Loan \| Term loan facility \| Minimum
Debt Instrument [Line Items]
Interest expense								5,800,000
Term Loan \| Term loan facility \| Maximum
Debt Instrument [Line Items]
Interest expense								38,200,000
Deerfield ELGX Revolver, LLC
Debt Instrument [Line Items]
Short-term debt						$ 143,300,000		$ 143,300,000