3.26.1 html 219 444 1 true 77 0 false 10 false false R1.htm 0000001 - Document - COVER PAGE Sheet http://www.assertiotx.com/role/COVERPAGE COVER PAGE Cover 1 false false R2.htm 0000002 - Document - Audit Information Sheet http://www.assertiotx.com/role/AuditInformation Audit Information Cover 2 false false R3.htm 9952151 - Statement - CONSOLIDATED BALANCE SHEETS Sheet http://www.assertiotx.com/role/CONSOLIDATEDBALANCESHEETS CONSOLIDATED BALANCE SHEETS Statements 3 false false R4.htm 9952152 - Statement - CONSOLIDATED BALANCE SHEETS (Parenthetical) Sheet http://www.assertiotx.com/role/CONSOLIDATEDBALANCESHEETSParenthetical CONSOLIDATED BALANCE SHEETS (Parenthetical) Statements 4 false false R5.htm 9952153 - Statement - CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS Sheet http://www.assertiotx.com/role/CONSOLIDATEDSTATEMENTSOFCOMPREHENSIVELOSS CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS Statements 5 false false R6.htm 9952154 - Statement - CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS (Parenthetical) Sheet http://www.assertiotx.com/role/CONSOLIDATEDSTATEMENTSOFCOMPREHENSIVELOSSParenthetical CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS (Parenthetical) Statements 6 false false R7.htm 9952155 - Statement - CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY Sheet http://www.assertiotx.com/role/CONSOLIDATEDSTATEMENTSOFSHAREHOLDERSEQUITY CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY Statements 7 false false R8.htm 9952156 - Statement - CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY (Parenthetical) Sheet http://www.assertiotx.com/role/CONSOLIDATEDSTATEMENTSOFSHAREHOLDERSEQUITYParenthetical CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY (Parenthetical) Statements 8 false false R9.htm 9952157 - Statement - CONSOLIDATED STATEMENTS OF CASH FLOWS Sheet http://www.assertiotx.com/role/CONSOLIDATEDSTATEMENTSOFCASHFLOWS CONSOLIDATED STATEMENTS OF CASH FLOWS Statements 9 false false R10.htm 9952158 - Disclosure - ORGANIZATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Sheet http://www.assertiotx.com/role/ORGANIZATIONANDSUMMARYOFSIGNIFICANTACCOUNTINGPOLICIES ORGANIZATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Notes 10 false false R11.htm 9952159 - Disclosure - DIVESTITURES AND STRATEGIC TRANSACTIONS Sheet http://www.assertiotx.com/role/DIVESTITURESANDSTRATEGICTRANSACTIONS DIVESTITURES AND STRATEGIC TRANSACTIONS Notes 11 false false R12.htm 9952160 - Disclosure - REVENUE Sheet http://www.assertiotx.com/role/REVENUE REVENUE Notes 12 false false R13.htm 9952161 - Disclosure - SUPPLEMENTAL BALANCE SHEET DETAILS Sheet http://www.assertiotx.com/role/SUPPLEMENTALBALANCESHEETDETAILS SUPPLEMENTAL BALANCE SHEET DETAILS Notes 13 false false R14.htm 9952162 - Disclosure - INTANGIBLE ASSETS Sheet http://www.assertiotx.com/role/INTANGIBLEASSETS INTANGIBLE ASSETS Notes 14 false false R15.htm 9952163 - Disclosure - DEBT Sheet http://www.assertiotx.com/role/DEBT DEBT Notes 15 false false R16.htm 9952164 - Disclosure - LEASES Sheet http://www.assertiotx.com/role/LEASES LEASES Notes 16 false false R17.htm 9952165 - Disclosure - COMMITMENTS AND CONTINGENCIES Sheet http://www.assertiotx.com/role/COMMITMENTSANDCONTINGENCIES COMMITMENTS AND CONTINGENCIES Notes 17 false false R18.htm 9952166 - Disclosure - EMPLOYEE BENEFIT PLANS Sheet http://www.assertiotx.com/role/EMPLOYEEBENEFITPLANS EMPLOYEE BENEFIT PLANS Notes 18 false false R19.htm 9952167 - Disclosure - STOCK-BASED COMPENSATION Sheet http://www.assertiotx.com/role/STOCKBASEDCOMPENSATION STOCK-BASED COMPENSATION Notes 19 false false R20.htm 9952168 - Disclosure - SHAREHOLDERS' EQUITY Sheet http://www.assertiotx.com/role/SHAREHOLDERSEQUITY SHAREHOLDERS' EQUITY Notes 20 false false R21.htm 9952169 - Disclosure - NET LOSS PER SHARE Sheet http://www.assertiotx.com/role/NETLOSSPERSHARE NET LOSS PER SHARE Notes 21 false false R22.htm 9952170 - Disclosure - FAIR VALUE Sheet http://www.assertiotx.com/role/FAIRVALUE FAIR VALUE Notes 22 false false R23.htm 9952171 - Disclosure - INCOME TAXES Sheet http://www.assertiotx.com/role/INCOMETAXES INCOME TAXES Notes 23 false false R24.htm 9952172 - Disclosure - SEGMENT INFORMATION Sheet http://www.assertiotx.com/role/SEGMENTINFORMATION SEGMENT INFORMATION Notes 24 false false R25.htm 9952173 - Disclosure - RESTRUCTURING CHARGES Sheet http://www.assertiotx.com/role/RESTRUCTURINGCHARGES RESTRUCTURING CHARGES Notes 25 false false R26.htm 9952174 - Disclosure - SCHEDULE II: VALUATION AND QUALIFYING ACCOUNTS Sheet http://www.assertiotx.com/role/SCHEDULEIIVALUATIONANDQUALIFYINGACCOUNTS SCHEDULE II: VALUATION AND QUALIFYING ACCOUNTS Notes 26 false false R27.htm 995445 - Disclosure - Insider Trading Arrangements Sheet http://xbrl.sec.gov/ecd/role/InsiderTradingArrangements Insider Trading Arrangements Notes 27 false false R28.htm 995447 - Disclosure - Insider Trading Policies and Procedures Sheet http://xbrl.sec.gov/ecd/role/InsiderTradingPoliciesProc Insider Trading Policies and Procedures Notes 28 false false R29.htm 995550 - Disclosure - Cybersecurity Risk Management and Strategy Disclosure Sheet http://xbrl.sec.gov/cyd/role/CybersecurityRiskManagementAndStrategyDisclosure Cybersecurity Risk Management and Strategy Disclosure Notes 29 false false R30.htm 9955511 - Disclosure - ORGANIZATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies) Sheet http://www.assertiotx.com/role/ORGANIZATIONANDSUMMARYOFSIGNIFICANTACCOUNTINGPOLICIESPolicies ORGANIZATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies) Policies 30 false false R31.htm 9955512 - Disclosure - ORGANIZATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Tables) Sheet http://www.assertiotx.com/role/ORGANIZATIONANDSUMMARYOFSIGNIFICANTACCOUNTINGPOLICIESTables ORGANIZATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Tables) Tables http://www.assertiotx.com/role/ORGANIZATIONANDSUMMARYOFSIGNIFICANTACCOUNTINGPOLICIES 31 false false R32.htm 9955513 - Disclosure - REVENUE (Tables) Sheet http://www.assertiotx.com/role/REVENUETables REVENUE (Tables) Tables http://www.assertiotx.com/role/REVENUE 32 false false R33.htm 9955514 - Disclosure - SUPPLEMENTAL BALANCE SHEET DETAILS (Tables) Sheet http://www.assertiotx.com/role/SUPPLEMENTALBALANCESHEETDETAILSTables SUPPLEMENTAL BALANCE SHEET DETAILS (Tables) Tables http://www.assertiotx.com/role/SUPPLEMENTALBALANCESHEETDETAILS 33 false false R34.htm 9955515 - Disclosure - INTANGIBLE ASSETS (Tables) Sheet http://www.assertiotx.com/role/INTANGIBLEASSETSTables INTANGIBLE ASSETS (Tables) Tables http://www.assertiotx.com/role/INTANGIBLEASSETS 34 false false R35.htm 9955516 - Disclosure - DEBT (Tables) Sheet http://www.assertiotx.com/role/DEBTTables DEBT (Tables) Tables http://www.assertiotx.com/role/DEBT 35 false false R36.htm 9955517 - Disclosure - LEASES (Tables) Sheet http://www.assertiotx.com/role/LEASESTables LEASES (Tables) Tables http://www.assertiotx.com/role/LEASES 36 false false R37.htm 9955518 - Disclosure - STOCK-BASED COMPENSATION (Tables) Sheet http://www.assertiotx.com/role/STOCKBASEDCOMPENSATIONTables STOCK-BASED COMPENSATION (Tables) Tables http://www.assertiotx.com/role/STOCKBASEDCOMPENSATION 37 false false R38.htm 9955519 - Disclosure - NET LOSS PER SHARE (Tables) Sheet http://www.assertiotx.com/role/NETLOSSPERSHARETables NET LOSS PER SHARE (Tables) Tables http://www.assertiotx.com/role/NETLOSSPERSHARE 38 false false R39.htm 9955520 - Disclosure - FAIR VALUE (Tables) Sheet http://www.assertiotx.com/role/FAIRVALUETables FAIR VALUE (Tables) Tables http://www.assertiotx.com/role/FAIRVALUE 39 false false R40.htm 9955521 - Disclosure - INCOME TAXES (Tables) Sheet http://www.assertiotx.com/role/INCOMETAXESTables INCOME TAXES (Tables) Tables http://www.assertiotx.com/role/INCOMETAXES 40 false false R41.htm 9955522 - Disclosure - SEGMENT INFORMATION (Tables) Sheet http://www.assertiotx.com/role/SEGMENTINFORMATIONTables SEGMENT INFORMATION (Tables) Tables http://www.assertiotx.com/role/SEGMENTINFORMATION 41 false false R42.htm 9955523 - Disclosure - RESTRUCTURING CHARGES (Tables) Sheet http://www.assertiotx.com/role/RESTRUCTURINGCHARGESTables RESTRUCTURING CHARGES (Tables) Tables http://www.assertiotx.com/role/RESTRUCTURINGCHARGES 42 false false R43.htm 9955524 - Disclosure - ORGANIZATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Reverse Stock Split Narrative (Details) Sheet http://www.assertiotx.com/role/ORGANIZATIONANDSUMMARYOFSIGNIFICANTACCOUNTINGPOLICIESReverseStockSplitNarrativeDetails ORGANIZATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Reverse Stock Split Narrative (Details) Details 43 false false R44.htm 9955525 - Disclosure - ORGANIZATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Schedule of Useful Lives of Property and Equipment (Details) Sheet http://www.assertiotx.com/role/ORGANIZATIONANDSUMMARYOFSIGNIFICANTACCOUNTINGPOLICIESScheduleofUsefulLivesofPropertyandEquipmentDetails ORGANIZATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Schedule of Useful Lives of Property and Equipment (Details) Details 44 false false R45.htm 9955526 - Disclosure - ORGANIZATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Revenue Recognition Narrative (Details) Sheet http://www.assertiotx.com/role/ORGANIZATIONANDSUMMARYOFSIGNIFICANTACCOUNTINGPOLICIESRevenueRecognitionNarrativeDetails ORGANIZATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Revenue Recognition Narrative (Details) Details 45 false false R46.htm 9955527 - Disclosure - ORGANIZATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Advertising Costs Narrative (Details) Sheet http://www.assertiotx.com/role/ORGANIZATIONANDSUMMARYOFSIGNIFICANTACCOUNTINGPOLICIESAdvertisingCostsNarrativeDetails ORGANIZATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Advertising Costs Narrative (Details) Details 46 false false R47.htm 9955528 - Disclosure - ORGANIZATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Schedule of Revenue and Accounts Receivable Customer Concentration Risk (Details) Sheet http://www.assertiotx.com/role/ORGANIZATIONANDSUMMARYOFSIGNIFICANTACCOUNTINGPOLICIESScheduleofRevenueandAccountsReceivableCustomerConcentrationRiskDetails ORGANIZATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Schedule of Revenue and Accounts Receivable Customer Concentration Risk (Details) Details 47 false false R48.htm 9955529 - Disclosure - DIVESTITURES AND STRATEGIC TRANSACTIONS (Details) Sheet http://www.assertiotx.com/role/DIVESTITURESANDSTRATEGICTRANSACTIONSDetails DIVESTITURES AND STRATEGIC TRANSACTIONS (Details) Details http://www.assertiotx.com/role/DIVESTITURESANDSTRATEGICTRANSACTIONS 48 false false R49.htm 9955530 - Disclosure - REVENUE - Schedule of Net Revenue (Details) Sheet http://www.assertiotx.com/role/REVENUEScheduleofNetRevenueDetails REVENUE - Schedule of Net Revenue (Details) Details 49 false false R50.htm 9955531 - Disclosure - REVENUE - Narrative (Details) Sheet http://www.assertiotx.com/role/REVENUENarrativeDetails REVENUE - Narrative (Details) Details 50 false false R51.htm 9955532 - Disclosure - REVENUE - Schedule of Accrued Rebates, Returns and Discounts (Details) Sheet http://www.assertiotx.com/role/REVENUEScheduleofAccruedRebatesReturnsandDiscountsDetails REVENUE - Schedule of Accrued Rebates, Returns and Discounts (Details) Details 51 false false R52.htm 9955533 - Disclosure - SUPPLEMENTAL BALANCE SHEET DETAILS - Schedule of Account Receivable, Net (Details) Sheet http://www.assertiotx.com/role/SUPPLEMENTALBALANCESHEETDETAILSScheduleofAccountReceivableNetDetails SUPPLEMENTAL BALANCE SHEET DETAILS - Schedule of Account Receivable, Net (Details) Details 52 false false R53.htm 9955534 - Disclosure - SUPPLEMENTAL BALANCE SHEET DETAILS - Narrative (Details) Sheet http://www.assertiotx.com/role/SUPPLEMENTALBALANCESHEETDETAILSNarrativeDetails SUPPLEMENTAL BALANCE SHEET DETAILS - Narrative (Details) Details 53 false false R54.htm 9955535 - Disclosure - SUPPLEMENTAL BALANCE SHEET DETAILS - Schedule of Inventories, Net (Details) Sheet http://www.assertiotx.com/role/SUPPLEMENTALBALANCESHEETDETAILSScheduleofInventoriesNetDetails SUPPLEMENTAL BALANCE SHEET DETAILS - Schedule of Inventories, Net (Details) Details 54 false false R55.htm 9955536 - Disclosure - SUPPLEMENTAL BALANCE SHEET DETAILS - Schedule of Prepaid and Other Current Assets (Details) Sheet http://www.assertiotx.com/role/SUPPLEMENTALBALANCESHEETDETAILSScheduleofPrepaidandOtherCurrentAssetsDetails SUPPLEMENTAL BALANCE SHEET DETAILS - Schedule of Prepaid and Other Current Assets (Details) Details 55 false false R56.htm 9955537 - Disclosure - SUPPLEMENTAL BALANCE SHEET DETAILS - Schedule of Property and Equipment (Details) Sheet http://www.assertiotx.com/role/SUPPLEMENTALBALANCESHEETDETAILSScheduleofPropertyandEquipmentDetails SUPPLEMENTAL BALANCE SHEET DETAILS - Schedule of Property and Equipment (Details) Details 56 false false R57.htm 9955538 - Disclosure - SUPPLEMENTAL BALANCE SHEET DETAILS - Schedule of Accrued Liabilities (Details) Sheet http://www.assertiotx.com/role/SUPPLEMENTALBALANCESHEETDETAILSScheduleofAccruedLiabilitiesDetails SUPPLEMENTAL BALANCE SHEET DETAILS - Schedule of Accrued Liabilities (Details) Details 57 false false R58.htm 9955539 - Disclosure - SUPPLEMENTAL BALANCE SHEET DETAILS - Schedule of Other Long-term Liabilities (Details) Sheet http://www.assertiotx.com/role/SUPPLEMENTALBALANCESHEETDETAILSScheduleofOtherLongtermLiabilitiesDetails SUPPLEMENTAL BALANCE SHEET DETAILS - Schedule of Other Long-term Liabilities (Details) Details 58 false false R59.htm 9955540 - Disclosure - INTANGIBLE ASSETS - Schedule of Gross Carrying Amounts and Net Book Values of Intangible Assets and Goodwill (Details) Sheet http://www.assertiotx.com/role/INTANGIBLEASSETSScheduleofGrossCarryingAmountsandNetBookValuesofIntangibleAssetsandGoodwillDetails INTANGIBLE ASSETS - Schedule of Gross Carrying Amounts and Net Book Values of Intangible Assets and Goodwill (Details) Details 59 false false R60.htm 9955541 - Disclosure - INTANGIBLE ASSETS - Narrative (Details) Sheet http://www.assertiotx.com/role/INTANGIBLEASSETSNarrativeDetails INTANGIBLE ASSETS - Narrative (Details) Details 60 false false R61.htm 9955542 - Disclosure - INTANGIBLE ASSETS - Schedule of the Future Amortization Expenses of Intangible Assets (Details) Sheet http://www.assertiotx.com/role/INTANGIBLEASSETSScheduleoftheFutureAmortizationExpensesofIntangibleAssetsDetails INTANGIBLE ASSETS - Schedule of the Future Amortization Expenses of Intangible Assets (Details) Details 61 false false R62.htm 9955543 - Disclosure - DEBT - Narrative (Details) Sheet http://www.assertiotx.com/role/DEBTNarrativeDetails DEBT - Narrative (Details) Details 62 false false R63.htm 9955544 - Disclosure - DEBT - Schedule of Carrying Values Convertible Notes (Details) Notes http://www.assertiotx.com/role/DEBTScheduleofCarryingValuesConvertibleNotesDetails DEBT - Schedule of Carrying Values Convertible Notes (Details) Details 63 false false R64.htm 9955545 - Disclosure - DEBT - Schedule of Debt Related Interest (Details) Sheet http://www.assertiotx.com/role/DEBTScheduleofDebtRelatedInterestDetails DEBT - Schedule of Debt Related Interest (Details) Details 64 false false R65.htm 9955546 - Disclosure - LEASES - Narrative (Details) Sheet http://www.assertiotx.com/role/LEASESNarrativeDetails LEASES - Narrative (Details) Details 65 false false R66.htm 9955547 - Disclosure - LEASES - Schedule of Lease Cost Components (Details) Sheet http://www.assertiotx.com/role/LEASESScheduleofLeaseCostComponentsDetails LEASES - Schedule of Lease Cost Components (Details) Details 66 false false R67.htm 9955548 - Disclosure - LEASES - Schedule of Supplemental Cash Flow and Other Information (Details) Sheet http://www.assertiotx.com/role/LEASESScheduleofSupplementalCashFlowandOtherInformationDetails LEASES - Schedule of Supplemental Cash Flow and Other Information (Details) Details 67 false false R68.htm 9955549 - Disclosure - LEASES - Schedule of Supplemental Balance Sheet Information (Details) Sheet http://www.assertiotx.com/role/LEASESScheduleofSupplementalBalanceSheetInformationDetails LEASES - Schedule of Supplemental Balance Sheet Information (Details) Details 68 false false R69.htm 9955550 - Disclosure - LEASES - Schedule of Other Operating Lease Information (Details) Sheet http://www.assertiotx.com/role/LEASESScheduleofOtherOperatingLeaseInformationDetails LEASES - Schedule of Other Operating Lease Information (Details) Details 69 false false R70.htm 9955551 - Disclosure - LEASES - Schedule of Maturity of Lease Liabilities (Details) Sheet http://www.assertiotx.com/role/LEASESScheduleofMaturityofLeaseLiabilitiesDetails LEASES - Schedule of Maturity of Lease Liabilities (Details) Details 70 false false R71.htm 9955552 - Disclosure - COMMITMENTS AND CONTINGENCIES - Supply Agreements (Details) Sheet http://www.assertiotx.com/role/COMMITMENTSANDCONTINGENCIESSupplyAgreementsDetails COMMITMENTS AND CONTINGENCIES - Supply Agreements (Details) Details 71 false false R72.htm 9955553 - Disclosure - COMMITMENTS AND CONTINGENCIES - Stockholder Actions (Details) Sheet http://www.assertiotx.com/role/COMMITMENTSANDCONTINGENCIESStockholderActionsDetails COMMITMENTS AND CONTINGENCIES - Stockholder Actions (Details) Details 72 false false R73.htm 9955554 - Disclosure - EMPLOYEE BENEFIT PLANS (Details) Sheet http://www.assertiotx.com/role/EMPLOYEEBENEFITPLANSDetails EMPLOYEE BENEFIT PLANS (Details) Details http://www.assertiotx.com/role/EMPLOYEEBENEFITPLANS 73 false false R74.htm 9955555 - Disclosure - STOCK-BASED COMPENSATION - Stock-Based Compensation Expense Narrative (Details) Sheet http://www.assertiotx.com/role/STOCKBASEDCOMPENSATIONStockBasedCompensationExpenseNarrativeDetails STOCK-BASED COMPENSATION - Stock-Based Compensation Expense Narrative (Details) Details 74 false false R75.htm 9955556 - Disclosure - STOCK-BASED COMPENSATION - 2014 Omnibus Incentive Plan Narrative (Details) Sheet http://www.assertiotx.com/role/STOCKBASEDCOMPENSATION2014OmnibusIncentivePlanNarrativeDetails STOCK-BASED COMPENSATION - 2014 Omnibus Incentive Plan Narrative (Details) Details 75 false false R76.htm 9955557 - Disclosure - STOCK-BASED COMPENSATION - Inducement Incentive Plan Narrative (Details) Sheet http://www.assertiotx.com/role/STOCKBASEDCOMPENSATIONInducementIncentivePlanNarrativeDetails STOCK-BASED COMPENSATION - Inducement Incentive Plan Narrative (Details) Details 76 false false R77.htm 9955558 - Disclosure - STOCK-BASED COMPENSATION - Schedule of Time-Based Stock Options (Details) Sheet http://www.assertiotx.com/role/STOCKBASEDCOMPENSATIONScheduleofTimeBasedStockOptionsDetails STOCK-BASED COMPENSATION - Schedule of Time-Based Stock Options (Details) Details 77 false false R78.htm 9955559 - Disclosure - STOCK-BASED COMPENSATION - Time-Based Stock Options Narrative (Details) Sheet http://www.assertiotx.com/role/STOCKBASEDCOMPENSATIONTimeBasedStockOptionsNarrativeDetails STOCK-BASED COMPENSATION - Time-Based Stock Options Narrative (Details) Details 78 false false R79.htm 9955560 - Disclosure - STOCK-BASED COMPENSATION - Schedule of Options Activity (Details) Sheet http://www.assertiotx.com/role/STOCKBASEDCOMPENSATIONScheduleofOptionsActivityDetails STOCK-BASED COMPENSATION - Schedule of Options Activity (Details) Details 79 false false R80.htm 9955561 - Disclosure - STOCK-BASED COMPENSATION - Schedule of Time-Based Restricted Stock Units (Details) Sheet http://www.assertiotx.com/role/STOCKBASEDCOMPENSATIONScheduleofTimeBasedRestrictedStockUnitsDetails STOCK-BASED COMPENSATION - Schedule of Time-Based Restricted Stock Units (Details) Details 80 false false R81.htm 9955562 - Disclosure - STOCK-BASED COMPENSATION - Time-Based Restricted Stock Units Narrative (Details) Sheet http://www.assertiotx.com/role/STOCKBASEDCOMPENSATIONTimeBasedRestrictedStockUnitsNarrativeDetails STOCK-BASED COMPENSATION - Time-Based Restricted Stock Units Narrative (Details) Details 81 false false R82.htm 9955563 - Disclosure - STOCK-BASED COMPENSATION - Performance-based Stock Options and Restricted Stock Units Narrative (Details) Sheet http://www.assertiotx.com/role/STOCKBASEDCOMPENSATIONPerformancebasedStockOptionsandRestrictedStockUnitsNarrativeDetails STOCK-BASED COMPENSATION - Performance-based Stock Options and Restricted Stock Units Narrative (Details) Details 82 false false R83.htm 9955564 - Disclosure - SHAREHOLDERS' EQUITY (Details) Sheet http://www.assertiotx.com/role/SHAREHOLDERSEQUITYDetails SHAREHOLDERS' EQUITY (Details) Details http://www.assertiotx.com/role/SHAREHOLDERSEQUITY 83 false false R84.htm 9955565 - Disclosure - NET LOSS PER SHARE - Schedule of Calculation of Basic and Diluted Net Loss Per Common Share (Details) Sheet http://www.assertiotx.com/role/NETLOSSPERSHAREScheduleofCalculationofBasicandDilutedNetLossPerCommonShareDetails NET LOSS PER SHARE - Schedule of Calculation of Basic and Diluted Net Loss Per Common Share (Details) Details 84 false false R85.htm 9955566 - Disclosure - NET LOSS PER SHARE - Schedule of Potentially Dilutive Common Shares (Details) Sheet http://www.assertiotx.com/role/NETLOSSPERSHAREScheduleofPotentiallyDilutiveCommonSharesDetails NET LOSS PER SHARE - Schedule of Potentially Dilutive Common Shares (Details) Details 85 false false R86.htm 9955567 - Disclosure - FAIR VALUE - Schedule of Fair Value Hierarchy for Financial Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) Sheet http://www.assertiotx.com/role/FAIRVALUEScheduleofFairValueHierarchyforFinancialAssetsandLiabilitiesMeasuredatFairValueonaRecurringBasisDetails FAIR VALUE - Schedule of Fair Value Hierarchy for Financial Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) Details 86 false false R87.htm 9955568 - Disclosure - FAIR VALUE - Narrative (Details) Sheet http://www.assertiotx.com/role/FAIRVALUENarrativeDetails FAIR VALUE - Narrative (Details) Details 87 false false R88.htm 9955569 - Disclosure - FAIR VALUE - Schedule of Changes in Fair Value of Contingent Consideration (Details) Sheet http://www.assertiotx.com/role/FAIRVALUEScheduleofChangesinFairValueofContingentConsiderationDetails FAIR VALUE - Schedule of Changes in Fair Value of Contingent Consideration (Details) Details 88 false false R89.htm 9955570 - Disclosure - FAIR VALUE - Schedule of Changes in Fair Value of Derivative Liability (Details) Sheet http://www.assertiotx.com/role/FAIRVALUEScheduleofChangesinFairValueofDerivativeLiabilityDetails FAIR VALUE - Schedule of Changes in Fair Value of Derivative Liability (Details) Details 89 false false R90.htm 9955571 - Disclosure - INCOME TAXES - Schedule of Net Loss Before Income Taxes by Source (Details) Sheet http://www.assertiotx.com/role/INCOMETAXESScheduleofNetLossBeforeIncomeTaxesbySourceDetails INCOME TAXES - Schedule of Net Loss Before Income Taxes by Source (Details) Details 90 false false R91.htm 9955572 - Disclosure - INCOME TAXES - Schedule of Income Taxes (Details) Sheet http://www.assertiotx.com/role/INCOMETAXESScheduleofIncomeTaxesDetails INCOME TAXES - Schedule of Income Taxes (Details) Details 91 false false R92.htm 9955573 - Disclosure - INCOME TAXES - Schedule of Reconciliation of Income Taxes at Statutory Federal Income Tax Rate to Actual Tax Rate Under ASU 2023-09 (Details) Sheet http://www.assertiotx.com/role/INCOMETAXESScheduleofReconciliationofIncomeTaxesatStatutoryFederalIncomeTaxRatetoActualTaxRateUnderASU202309Details INCOME TAXES - Schedule of Reconciliation of Income Taxes at Statutory Federal Income Tax Rate to Actual Tax Rate Under ASU 2023-09 (Details) Details 92 false false R93.htm 9955574 - Disclosure - INCOME TAXES - Narrative (Details) Sheet http://www.assertiotx.com/role/INCOMETAXESNarrativeDetails INCOME TAXES - Narrative (Details) Details 93 false false R94.htm 9955575 - Disclosure - INCOME TAXES - Schedule of Reconciliation of Income Taxes at Statutory Federal Income Tax Rate to Actual Tax Rate in 2024 (Details) Sheet http://www.assertiotx.com/role/INCOMETAXESScheduleofReconciliationofIncomeTaxesatStatutoryFederalIncomeTaxRatetoActualTaxRatein2024Details INCOME TAXES - Schedule of Reconciliation of Income Taxes at Statutory Federal Income Tax Rate to Actual Tax Rate in 2024 (Details) Details 94 false false R95.htm 9955576 - Disclosure - INCOME TAXES - Schedule of Significant Components of the Company's Deferred Income Taxes (Details) Sheet http://www.assertiotx.com/role/INCOMETAXESScheduleofSignificantComponentsoftheCompanysDeferredIncomeTaxesDetails INCOME TAXES - Schedule of Significant Components of the Company's Deferred Income Taxes (Details) Details 95 false false R96.htm 9955577 - Disclosure - INCOME TAXES - Schedule of Cash Income Taxes Paid, Net of Refunds Received (Details) Sheet http://www.assertiotx.com/role/INCOMETAXESScheduleofCashIncomeTaxesPaidNetofRefundsReceivedDetails INCOME TAXES - Schedule of Cash Income Taxes Paid, Net of Refunds Received (Details) Details 96 false false R97.htm 9955578 - Disclosure - INCOME TAXES - Schedule of Activity Related to Unrecognized Tax Benefits (Details) Sheet http://www.assertiotx.com/role/INCOMETAXESScheduleofActivityRelatedtoUnrecognizedTaxBenefitsDetails INCOME TAXES - Schedule of Activity Related to Unrecognized Tax Benefits (Details) Details 97 false false R98.htm 9955579 - Disclosure - SEGMENT INFORMATION - Narrative (Details) Sheet http://www.assertiotx.com/role/SEGMENTINFORMATIONNarrativeDetails SEGMENT INFORMATION - Narrative (Details) Details 98 false false R99.htm 9955580 - Disclosure - SEGMENT INFORMATION - Schedule of Selling, General and Administrative Expenses (Details) Sheet http://www.assertiotx.com/role/SEGMENTINFORMATIONScheduleofSellingGeneralandAdministrativeExpensesDetails SEGMENT INFORMATION - Schedule of Selling, General and Administrative Expenses (Details) Details 99 false false R100.htm 9955581 - Disclosure - RESTRUCTURING CHARGES - Narrative (Details) Sheet http://www.assertiotx.com/role/RESTRUCTURINGCHARGESNarrativeDetails RESTRUCTURING CHARGES - Narrative (Details) Details 100 false false R101.htm 9955582 - Disclosure - RESTRUCTURING CHARGES - Schedule of Accrued Restructuring and Severance Costs (Details) Sheet http://www.assertiotx.com/role/RESTRUCTURINGCHARGESScheduleofAccruedRestructuringandSeveranceCostsDetails RESTRUCTURING CHARGES - Schedule of Accrued Restructuring and Severance Costs (Details) Details 101 false false R102.htm 9955583 - Disclosure - SCHEDULE II: VALUATION AND QUALIFYING ACCOUNTS (Details) Sheet http://www.assertiotx.com/role/SCHEDULEIIVALUATIONANDQUALIFYINGACCOUNTSDetails SCHEDULE II: VALUATION AND QUALIFYING ACCOUNTS (Details) Details http://www.assertiotx.com/role/SCHEDULEIIVALUATIONANDQUALIFYINGACCOUNTS 102 false false All Reports Book All Reports asrt-20251231.htm asrt-20251231.xsd asrt-20251231_cal.xml asrt-20251231_def.xml asrt-20251231_lab.xml asrt-20251231_pre.xml http://fasb.org/srt/2025 http://fasb.org/us-gaap/2025 http://xbrl.sec.gov/cyd/2025 http://xbrl.sec.gov/dei/2025 http://xbrl.sec.gov/ecd/2025 true true