3.19.1 html 137 251 1 false 45 0 false 9 false false R1.htm 0001000 - Document - Document and Entity Information Sheet http://www.regulusrx.com/role/DocumentAndEntityInformation Document and Entity Information Cover 1 false false R2.htm 1001000 - Statement - Condensed Balance Sheets Sheet http://www.regulusrx.com/role/CondensedBalanceSheets Condensed Balance Sheets Statements 2 false false R3.htm 1001000 - Statement - Condensed Statements of Operations and Comprehensive Loss Sheet http://www.regulusrx.com/role/CondensedStatementsOfOperationsAndComprehensiveLoss Condensed Statements of Operations and Comprehensive Loss Statements 3 false false R4.htm 1001501 - Statement - Condensed Balance Sheets (Parenthetical) Sheet http://www.regulusrx.com/role/CondensedBalanceSheetsParenthetical Condensed Balance Sheets (Parenthetical) Statements 4 false false R5.htm 1002000 - Statement - Statements of Stockholders' Equity (Deficit) Sheet http://www.regulusrx.com/role/StatementsOfStockholdersEquityDeficit Statements of Stockholders' Equity (Deficit) Statements 5 false false R6.htm 1003000 - Statement - Condensed Statements of Cash Flows Sheet http://www.regulusrx.com/role/CondensedStatementsOfCashFlows Condensed Statements of Cash Flows Statements 6 false false R7.htm 2101100 - Disclosure - Basis of Presentation and Summary of Significant Accounting Policies Sheet http://www.regulusrx.com/role/BasisOfPresentationAndSummaryOfSignificantAccountingPolicies Basis of Presentation and Summary of Significant Accounting Policies Notes 7 false false R8.htm 2102100 - Disclosure - Net Loss Per Share Sheet http://www.regulusrx.com/role/NetLossPerShare Net Loss Per Share Notes 8 false false R9.htm 2103100 - Disclosure - Investments Sheet http://www.regulusrx.com/role/Investments Investments Notes 9 false false R10.htm 2108100 - Disclosure - Fair Value Measurements Sheet http://www.regulusrx.com/role/FairValueMeasurements Fair Value Measurements Notes 10 false false R11.htm 2111100 - Disclosure - Term Loan Sheet http://www.regulusrx.com/role/TermLoan Term Loan Notes 11 false false R12.htm 2112100 - Disclosure - Stockholders' Equity Sheet http://www.regulusrx.com/role/StockholdersEquity Stockholders' Equity Notes 12 false false R13.htm 2117100 - Disclosure - Strategic Alliances and Collaborations Sheet http://www.regulusrx.com/role/StrategicAlliancesAndCollaborations Strategic Alliances and Collaborations Notes 13 false false R14.htm 2119100 - Disclosure - Leases Sheet http://www.regulusrx.com/role/Leases Leases Notes 14 false false R15.htm 2120100 - Disclosure - Subsequent Events Sheet http://www.regulusrx.com/role/SubsequentEvents Subsequent Events Notes 15 false false R16.htm 2201201 - Disclosure - Basis of Presentation and Summary of Significant Accounting Policies (Policies) Sheet http://www.regulusrx.com/role/BasisOfPresentationAndSummaryOfSignificantAccountingPoliciesPolicies Basis of Presentation and Summary of Significant Accounting Policies (Policies) Policies http://www.regulusrx.com/role/BasisOfPresentationAndSummaryOfSignificantAccountingPolicies 16 false false R17.htm 2308301 - Disclosure - Fair Value Measurements (Tables) Sheet http://www.regulusrx.com/role/FairValueMeasurementsTables Fair Value Measurements (Tables) Tables http://www.regulusrx.com/role/FairValueMeasurements 17 false false R18.htm 2311301 - Disclosure - Term Loan (Tables) Sheet http://www.regulusrx.com/role/TermLoanTables Term Loan (Tables) Tables http://www.regulusrx.com/role/TermLoan 18 false false R19.htm 2312301 - Disclosure - Stockholders' Equity (Tables) Sheet http://www.regulusrx.com/role/StockholdersEquityTables Stockholders' Equity (Tables) Tables http://www.regulusrx.com/role/StockholdersEquity 19 false false R20.htm 2319301 - Disclosure - Leases (Tables) Sheet http://www.regulusrx.com/role/LeasesTables Leases (Tables) Tables http://www.regulusrx.com/role/Leases 20 false false R21.htm 2401402 - Disclosure - Basis of Presentation and Summary of Significant Accounting Policies (Narrative) (Details) Sheet http://www.regulusrx.com/role/BasisOfPresentationAndSummaryOfSignificantAccountingPoliciesNarrativeDetails Basis of Presentation and Summary of Significant Accounting Policies (Narrative) (Details) Details http://www.regulusrx.com/role/BasisOfPresentationAndSummaryOfSignificantAccountingPoliciesPolicies 21 false false R22.htm 2402401 - Disclosure - Net Loss Per Share (Detail) Sheet http://www.regulusrx.com/role/NetLossPerShareDetail Net Loss Per Share (Detail) Details http://www.regulusrx.com/role/NetLossPerShare 22 false false R23.htm 2408402 - Disclosure - Fair Value Measurements (Fair Value Hierarchy for Assets and Liabilities Measured at Fair Value on Recurring Basis) (Detail) Sheet http://www.regulusrx.com/role/FairValueMeasurementsFairValueHierarchyForAssetsAndLiabilitiesMeasuredAtFairValueOnRecurringBasisDetail Fair Value Measurements (Fair Value Hierarchy for Assets and Liabilities Measured at Fair Value on Recurring Basis) (Detail) Details http://www.regulusrx.com/role/FairValueMeasurementsTables 23 false false R24.htm 2411402 - Disclosure - Term Loan (Details) Sheet http://www.regulusrx.com/role/TermLoanDetails Term Loan (Details) Details http://www.regulusrx.com/role/TermLoanTables 24 false false R25.htm 2411403 - Disclosure - Term Loan (Future Principal Payments) (Details) Sheet http://www.regulusrx.com/role/TermLoanFuturePrincipalPaymentsDetails Term Loan (Future Principal Payments) (Details) Details http://www.regulusrx.com/role/TermLoanTables 25 false false R26.htm 2412402 - Disclosure - Stockholders' Equity (Narrative) (Details) Sheet http://www.regulusrx.com/role/StockholdersEquityNarrativeDetails Stockholders' Equity (Narrative) (Details) Details http://www.regulusrx.com/role/StockholdersEquityTables 26 false false R27.htm 2412403 - Disclosure - Stockholders' Equity (Common Stock Reserved for Future Issuance) (Detail) Sheet http://www.regulusrx.com/role/StockholdersEquityCommonStockReservedForFutureIssuanceDetail Stockholders' Equity (Common Stock Reserved for Future Issuance) (Detail) Details http://www.regulusrx.com/role/StockholdersEquityTables 27 false false R28.htm 2412404 - Disclosure - Stockholders' Equity (Stock Option and RSU Activity) (Detail) Sheet http://www.regulusrx.com/role/StockholdersEquityStockOptionAndRsuActivityDetail Stockholders' Equity (Stock Option and RSU Activity) (Detail) Details http://www.regulusrx.com/role/StockholdersEquityTables 28 false false R29.htm 2412405 - Disclosure - Stockholders' Equity (Assumptions Used to Estimate Fair Value of Stock Options and Performance Stock and Employee Stock Purchase Plan) (Detail) Sheet http://www.regulusrx.com/role/StockholdersEquityAssumptionsUsedToEstimateFairValueOfStockOptionsAndPerformanceStockAndEmployeeStockPurchasePlanDetail Stockholders' Equity (Assumptions Used to Estimate Fair Value of Stock Options and Performance Stock and Employee Stock Purchase Plan) (Detail) Details http://www.regulusrx.com/role/StockholdersEquityTables 29 false false R30.htm 2412406 - Disclosure - Stockholders' Equity (Stock-Based Compensation Expense Allocation) (Detail) Sheet http://www.regulusrx.com/role/StockholdersEquityStockBasedCompensationExpenseAllocationDetail Stockholders' Equity (Stock-Based Compensation Expense Allocation) (Detail) Details http://www.regulusrx.com/role/StockholdersEquityTables 30 false false R31.htm 2417401 - Disclosure - Strategic Alliances and Collaborations (Detail) Sheet http://www.regulusrx.com/role/StrategicAlliancesAndCollaborationsDetail Strategic Alliances and Collaborations (Detail) Details http://www.regulusrx.com/role/StrategicAlliancesAndCollaborations 31 false false R32.htm 2419402 - Disclosure - Leases (Narrative) (Details) Sheet http://www.regulusrx.com/role/LeasesNarrativeDetails Leases (Narrative) (Details) Details http://www.regulusrx.com/role/LeasesTables 32 false false R33.htm 2419403 - Disclosure - Leases (Lease Asset and Liabilities) (Details) Sheet http://www.regulusrx.com/role/LeasesLeaseAssetAndLiabilitiesDetails Leases (Lease Asset and Liabilities) (Details) Details http://www.regulusrx.com/role/LeasesTables 33 false false R34.htm 2419404 - Disclosure - Leases (Lease Cost) (Details) Sheet http://www.regulusrx.com/role/LeasesLeaseCostDetails Leases (Lease Cost) (Details) Details http://www.regulusrx.com/role/LeasesTables 34 false false R35.htm 2419405 - Disclosure - Leases (Finance Maturities) (Details) Sheet http://www.regulusrx.com/role/LeasesFinanceMaturitiesDetails Leases (Finance Maturities) (Details) Details http://www.regulusrx.com/role/LeasesTables 35 false false R36.htm 2420401 - Disclosure - Subsequent Events (Seventh Amendment to Loan and Security Agreement) (Details) Sheet http://www.regulusrx.com/role/SubsequentEventsSeventhAmendmentToLoanAndSecurityAgreementDetails Subsequent Events (Seventh Amendment to Loan and Security Agreement) (Details) Details http://www.regulusrx.com/role/SubsequentEvents 36 false false R37.htm 2420402 - Disclosure - Subsequent Events (Security Purchase Agreement) (Details) Sheet http://www.regulusrx.com/role/SubsequentEventsSecurityPurchaseAgreementDetails Subsequent Events (Security Purchase Agreement) (Details) Details http://www.regulusrx.com/role/SubsequentEvents 37 false false R38.htm 2420403 - Disclosure - Subsequent Events (Eighth Amendment to Loan and Security Agreement) (Details) Sheet http://www.regulusrx.com/role/SubsequentEventsEighthAmendmentToLoanAndSecurityAgreementDetails Subsequent Events (Eighth Amendment to Loan and Security Agreement) (Details) Details http://www.regulusrx.com/role/SubsequentEvents 38 false false R9999.htm Uncategorized Items - rgls-20190331.xml Sheet http://xbrl.sec.gov/role/uncategorizedFacts Uncategorized Items - rgls-20190331.xml Cover 39 false false All Reports Book All Reports rgls-20190331.xml rgls-20190331.xsd rgls-20190331_cal.xml rgls-20190331_def.xml rgls-20190331_lab.xml rgls-20190331_pre.xml http://xbrl.sec.gov/dei/2018-01-31 http://fasb.org/srt/2018-01-31 http://fasb.org/us-gaap/2018-01-31 http://xbrl.sec.gov/country/2017-01-31 true true