Debt Covenant Cash Amount, Condition One

No definition available.

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Period Type:	instant

- Definition

Debt Covenant Cash Amount, Condition Two

+ References

No definition available.

+ Details

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Balance Type:	debit
Period Type:	instant

- Definition

Debt, Interest Only Payment Fee

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Debt, Maturity Extension Fee

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Minimum Cash, Debt Covenant

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Number of Monthly Payments

+ References

No definition available.

+ Details

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Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Number of Term Loans

+ References

No definition available.

+ Details

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

- Definition

Payment Fee

+ References

No definition available.

+ Details

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Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Prepayment Requirement of Loan From License Fees

+ References

No definition available.

+ Details

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Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Prepayment Requirement of Loan From License Fees, Amount

+ References

No definition available.

+ Details

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Balance Type:	debit
Period Type:	duration

- Definition

Revenue Recognition, Milestone Method, Potential Milestone Receivable

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
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Period Type:	instant

- Definition

Upfront Payment Received

+ References

No definition available.

+ Details

Name:	rgls_UpfrontPaymentReceived
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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
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Balance Type:	na
Period Type:	duration

- Definition

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

+ References

+ Details

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

- Definition

Effective interest rate for the funds borrowed under the debt agreement considering interest compounding and original issue discount or premium.

+ 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 (a)
-URI http://asc.fasb.org/extlink&oid=109500613&loc=SL6036836-161870

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
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-Name Accounting Standards Codification
-Topic 835
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-Section 45
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-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

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

+ References

+ Details

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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

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

- Definition

Amount, after accumulated amortization, of debt issuance costs. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.

+ References

+ Details

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Balance Type:	debit
Period Type:	instant

- Definition

The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
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-Name Accounting Standards Codification
-Topic 944
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-Section S99
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+ Details

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

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- 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
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+ Details

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

- Definition

Amount of cash inflow from issuance of long-term debt classified as other.

+ 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=118932676&loc=d3e3255-108585

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Term Loan (Details)					1 Months Ended
Term Loan (Details)	May 03, 2019 USD ($)	Apr. 09, 2019 USD ($)	Jun. 22, 2016 USD ($)	Jun. 17, 2016 USD ($) loan number_of_payment	Mar. 31, 2019 USD ($)	Nov. 30, 2018 USD ($)	Dec. 31, 2019 USD ($)	May 07, 2019 USD ($)	Nov. 05, 2018 USD ($)	Mar. 31, 2017 USD ($)
Debt Instrument [Line Items]
Upfront payment received					$ 1,800,000	$ 2,500,000
Debt Financing Agreement Tranche A
Debt Instrument [Line Items]
Maximum borrowing capacity				$ 20,000,000.0
Proceeds from borrowing under term loan			$ 20,000,000
Long-term debt							$ 14,681,000
Debt Financing Agreement Tranche B
Debt Instrument [Line Items]
Maximum borrowing capacity				10,000,000.0
Long-term line of credit										$ 0
Fourth Amendment
Debt Instrument [Line Items]
Prepayment requirement of loan from license fees									25.00%
Expected revenue through milestone payments									$ 10,000,000
Prepayment required for loan					$ 400,000	$ 600,000
Payment fee									5.50%
Seventh Amendment
Debt Instrument [Line Items]
Minimum cash, debt covenant		$ 10,000,000
Debt covenant, cash amount, condition one		10,000,000
Debt covenant, cash amount, condition two		5,000,000
Eight Amendment
Debt Instrument [Line Items]
Minimum cash, debt covenant								$ 20,000,000
Interest only payment fee	$ 100,000
Maturity extension fee	$ 700,000
Eight Amendment - Milestone Payment
Debt Instrument [Line Items]
Minimum cash, debt covenant		$ 10,000,000
Debt Financing Agreement
Debt Instrument [Line Items]
Maximum borrowing capacity				$ 30,000,000.0
Number of term loans \| loan				2
Stated interest rate, percentage				8.51%
Number of monthly payments \| number_of_payment				24
Long-term debt							14,700,000
Fee amount							1,900,000
Deferred finance costs							$ 100,000
Debt instrument effective rate							8.98%
Debt Financing Agreement \| London Interbank Offered Rate (LIBOR)
Debt Instrument [Line Items]
Basis spread on variable rate, percentage				0.44%
Minimum \| Seventh Amendment
Debt Instrument [Line Items]
Prepayment requirement of loan from license fees		25.00%
Prepayment required for loan		$ 5,000,000
Minimum \| Eight Amendment
Debt Instrument [Line Items]
Prepayment requirement of loan from license fees		75.00%
Maximum \| Seventh Amendment
Debt Instrument [Line Items]
Prepayment requirement of loan from license fees		75.00%
Maximum \| Eight Amendment
Debt Instrument [Line Items]
Prepayment requirement of loan from license fees		100.00%