Fair Value of Financial Assets and Liabilities - Additional Information (Details)

v3.24.1

Fair Value of Financial Assets and Liabilities - Additional Information (Details) - USD ($)		12 Months Ended	35 Months Ended
	Jan. 21, 2020	Dec. 31, 2023	Dec. 31, 2023	Dec. 31, 2022
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Aggregate principal amount of exchangeable notes			$ 40,691,000
Derivative liability for the exchange option, fair value		$ 0	0
Derivative liability, change of control feature, fair value		0	0
RLNs liability		7,503,000	7,503,000
Fair value, asset Level 3 transfers amount		0
Fair value, liabilities Level 3 transfers amount		0
Exchangeable Notes
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Aggregate principal amount of exchangeable notes			40,691,000
Private Placement \| Exchangeable Notes
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Aggregate principal amount of exchangeable notes			$ 40,691,000
Debt instrument, aggregate number of shares exchanged			3,760,155
Debt instrument, outstanding principal		$ 11,117,000	$ 11,117,000
Private Placement \| Securities
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Debt instrument price per ordinary share	$ 15	$ 11.123
Debt instrument, shares embedded within each unit, shares	66.666	89.9035
Debt instrument, shares embedded within each unit, value	$ 1,000	$ 1,000
Private Placement \| RLNs
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Debt instrument, aggregate potential payment capped value	160.00
Debt instrument, aggregate potential payment capped rate	4,000 times
Debt instrument, discount rate applied for royalty linked notes		22.00%	22.00%	22.00%

- Definition

Debt instrument aggregate amount of payment on royalty linked subordinated.

+ References

No definition available.

+ Details

Name:	itrm_DebtInstrumentAggregateAmountOfPaymentOnRoyaltyLinkedSubordinated
Namespace Prefix:	itrm_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Debt instrument aggregate potential payment capped rate.

+ References

No definition available.

+ Details

Name:	itrm_DebtInstrumentAggregatePotentialPaymentCappedRate
Namespace Prefix:	itrm_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Debt instrument, discount rate applied for royalty linked notes.

+ References

No definition available.

+ Details

Name:	itrm_DebtInstrumentDiscountRateAppliedForRoyaltyLinkedNotes
Namespace Prefix:	itrm_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Debt instrument price per ordinary share

+ References

No definition available.

+ Details

Name:	itrm_DebtInstrumentPricePerOrdinaryShare
Namespace Prefix:	itrm_
Data Type:	dtr-types:perShareItemType
Balance Type:	na
Period Type:	duration

- Definition

Debt instrument shares embedded within each unit shares.

+ References

No definition available.

+ Details

Name:	itrm_DebtInstrumentSharesEmbeddedWithinEachUnitShares
Namespace Prefix:	itrm_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

Debt instrument shares embedded within each unit value.

+ References

No definition available.

+ Details

Name:	itrm_DebtInstrumentSharesEmbeddedWithinEachUnitValue
Namespace Prefix:	itrm_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Debt repayment or conversion amount.

+ References

No definition available.

+ Details

Name:	itrm_DebtRepaymentOrConversionAmount
Namespace Prefix:	itrm_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Derivative liability, change of control feature, fair value.

+ References

No definition available.

+ Details

Name:	itrm_DerivativeLiabilityChangeOfControlFeatureFairValue
Namespace Prefix:	itrm_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Derivative liability exchange option fair value.

+ References

No definition available.

+ Details

Name:	itrm_DerivativeLiabilityExchangeOptionFairValue
Namespace Prefix:	itrm_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Royalty linked notes noncurrent fair value.

+ References

No definition available.

+ Details

Name:	itrm_RoyaltyLinkedNotesNoncurrentFairValue
Namespace Prefix:	itrm_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The number of shares issued in exchange for the original debt being converted in a noncash (or part noncash) transaction. "Part noncash" refers to that portion of the transaction not resulting in cash receipts or payments in the period.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 50
-Paragraph 3
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482913/230-10-50-3

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 50
-Paragraph 5
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482913/230-10-50-5

+ Details

Name:	us-gaap_DebtConversionConvertedInstrumentSharesIssued1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- 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

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22))
-SubTopic 10
-Topic 210
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480566/210-10-S99-1

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 942
-SubTopic 210
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(16))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479853/942-210-S99-1

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 4
-Subparagraph (b)(1)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481139/470-20-50-4

+ Details

Name:	us-gaap_DebtInstrumentCarryingAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
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_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of transfer of financial instrument classified as an asset into (out of) level 3 of the fair value hierarchy.

+ References

No definition available.

+ Details

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

- Definition

Amount of transfers of financial instrument classified as a liability into (out of) level 3 of the fair value hierarchy.

+ References

No definition available.

+ Details

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

- Details

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

- Details

Name:	us-gaap_SubsidiarySaleOfStockAxis=us-gaap_PrivatePlacementMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

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

Annual report pursuant to Section 13 and 15(d)

Fair Value of Financial Assets and Liabilities - Additional Information (Details)