Accounts Payable and Accrued Liabilities, Current [Abstract] Accrued compensation Employee-related Liabilities, Current Accrued consent fees Accrued Consent Fees, Current Accrued Consent Fees, Current Accrued taxes payable Taxes Payable, Current Accrued restructuring costs Restructuring Reserve Other accrued liabilities Other Accrued Liabilities, Current Total accrued liabilities Accrued Liabilities, Current Organization, Consolidation and Presentation of Financial Statements [Abstract] ORGANIZATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Organization, Consolidation, Basis of Presentation, Business Description and Accounting Policies [Text Block] Statement of Financial Position [Abstract] Statement [Table] Statement [Table] Long-term Debt, Type [Axis] Long-term Debt, Type [Axis] Long-term Debt, Type [Domain] Long-term Debt, Type [Domain] Senior Notes Senior Notes [Member] Convertible debt Convertible Debt [Member] Statement [Line Items] Statement [Line Items] ASSETS Assets [Abstract] Current assets: Assets, Current [Abstract] Cash and cash equivalents Cash and Cash Equivalents, at Carrying Value Accounts receivable, net Accounts Receivable, after Allowance for Credit Loss, Current Inventories, net Inventory, Net Consideration receivable from sale of Gralise Disposal Group, Consideration Receivable, Current Disposal Group, Consideration Receivable, Current Prepaid and other current assets Prepaid Expense and Other Assets, Current Total current assets Assets, Current Property and equipment, net Property, Plant and Equipment, Net Intangible assets, net Intangible Assets, Net (Excluding Goodwill) Investments, net Long-term Investments Other long-term assets Other Assets, Noncurrent Total assets Assets LIABILITIES AND SHAREHOLDERS’ EQUITY Liabilities and Equity [Abstract] Current liabilities: Liabilities, Current [Abstract] Accounts payable Accounts Payable, Current Accrued rebates, returns and discounts Customer Refund Liability, Current Accrued liabilities Senior Notes, current portion Debt, Current Interest payable Interest Payable, Current Other current liabilities Other Liabilities, Current Total current liabilities Liabilities, Current Senior Notes Long-term Debt Other long-term liabilities Other Liabilities, Noncurrent Total liabilities Liabilities Commitments and contingencies Commitments and Contingencies Shareholders’ equity: Stockholders' Equity Attributable to Parent [Abstract] Common stock Common Stock, Value, Issued Additional paid-in capital Additional Paid in Capital Accumulated deficit Retained Earnings (Accumulated Deficit) Total shareholders’ equity Stockholders' Equity Attributable to Parent Total liabilities and shareholders' equity Liabilities and Equity Summary of Significant Accounting Policies [Table] Summary of Significant Accounting Policies [Table] Information related to various accounting policies of the entity. Statistical Measurement [Axis] Statistical Measurement [Axis] Statistical Measurement [Domain] Statistical Measurement [Domain] Minimum Minimum [Member] Maximum Maximum [Member] Product and Service [Axis] Product and Service [Axis] Product and Service [Domain] Product and Service [Domain] NUCYNTA ER and NUCYNTA Nucynta Er And Nucynta [Member] Pertaining to NUCYNTA ER and NUCYNTA. Gralise Gralise [Member] Represents information pertaining to Gralise, a product of the entity. CAMBIA C A M B I A [Member] Represents information pertaining to CAMBIA, a product of the entity. Zipsor Zipsor [Member] Represents information pertaining to Zipsor, a product of the entity. Lazanda Lazanda [Member] Represents information pertaining to Lazanda, a product of the entity. Summary Of Significant Accounting Policies Summary of Significant Accounting Policies [Line Items] Product Sales and Royalties Revenue from Contract with Customer [Abstract] Collection period after delivery Receivables, Collection Period Represents the typical collection period for receivables after product delivery, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Product return period prior to expiration Product Return Period Prior to Expiration Date Represents the period prior to expiration of a product within which the entity accepts return of unsalable product from customers. Period after expiration for accepting unsalable product (up to) Product Return Period after Expiration Date Represents the period after expiration of a product within which the entity accepts return of unsalable product from customers. Product shelf-life Product Shelf Life from Date of Manufacturing Represents the product shelf-life from the manufacturing date. Discount taken off period after the quarter in which product shipped to the customer Discount Taken Off Period after Quarter in which Product Shipped to Customer Represents the discount taken off period after the quarter in which product shipped to the customer under certain wholesaler and retail pharmacy discounts. Cash discount Cash Discount to Customer for Prompt Payment as Percentage of Sales Price Represents the cash discount that the entity offers to its customers as an incentive for prompt payment as a percentage of sales price. Discount reimbursement period after filling of prescription subject to discount Discount Reimbursement Period after Filling of Prescription Subject to Discount Represents the discount reimbursement period after filling of prescription subject to discount. Period after the quarter in which prescription is filled for paying rebate Period After Quarter in which Prescription is Filled for Paying Rebate Represents the period after the quarter in which prescription is filled for paying rebate to each participating state under the Medicaid rebate programs. Contract with customer, managed care rebate liability, period after quarter in which prescription is filled Contract With Customer, Managed Care Rebate Liability, Period After Quarter In Which Prescription Is Filled Contract With Customer, Managed Care Rebate Liability, Period After Quarter In Which Prescription Is Filled Contract with customer, Medicare Part D coverage gap rebate liability, period after quarter in which prescription is filled Contract With Customer, Medicare Part D Coverage Gap Rebate Liability, Period After Quarter In Which Prescription Is Filled Contract With Customer, Medicare Part D Coverage Gap Rebate Liability, Period After Quarter In Which Prescription Is Filled Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Plan Name [Axis] Plan Name [Axis] Plan Name [Domain] Plan Name [Domain] Equity Incentive Plan 2014 Equity Incentive Plan 2014 [Member] Equity Incentive Plan 2014 [Member] Award Type [Axis] Award Type [Axis] Award Type [Domain] Award Type [Domain] Performance-based Restricted Stock Units Performance Based Restricted Stock Units [Member] Performance based restricted stock units. Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Awards vesting by the end of the first year Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage Vesting period Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period Share-based Payment Arrangement [Abstract] Schedule of stock-based compensation expense recognized for stock options, stock awards, restricted stock units and the Company's employee stock purchase program (ESPP) Share-based Payment Arrangement, Expensed and Capitalized, Amount [Table Text Block] Collaborative Arrangement and Arrangement Other than Collaborative [Table] Collaborative Arrangement and Arrangement Other than Collaborative [Table] Project [Axis] Project [Axis] Project [Domain] Project [Domain] Nuvo Pharmaceuticals Agreement Nuvo Pharmaceuticals Agreement [Member] Nuvo Pharmaceuticals Agreement [Member] Counterparty Name [Axis] Counterparty Name [Axis] Counterparty Name [Domain] Counterparty Name [Domain] Cambia Canada Cambia Canada [Member] Cambia Canada [Member] Collaborative Arrangement and Arrangement Other than Collaborative [Line Items] Collaborative Arrangement and Arrangement Other than Collaborative [Line Items] Revenue recognized Contract with Customer, Liability, Revenue Recognized Basis of Presentation Basis of Accounting, Policy [Policy Text Block] Principles of Consolidation Consolidation, Policy [Policy Text Block] Use of Estimates Use of Estimates, Policy [Policy Text Block] Revenue Recognition Revenue from Contract with Customer [Policy Text Block] Leases Lessee, Leases [Policy Text Block] Stock Based Compensation Share-based Payment Arrangement [Policy Text Block] Recently Adopted Accounting Pronouncements and Recently Issued Accounting Standards New Accounting Pronouncements, Policy [Policy Text Block] Net Income (Loss) Per Share Earnings Per Share, Policy [Policy Text Block] Long-term Debt, Unclassified [Abstract] Summary of the carrying value of the Senior Notes Schedule of Long-term Debt Instruments [Table Text Block] Summary of interest expense for the Notes Schedule of Interest Expense [Table Text Block] Tabular disclosure of the amount of interest expense. Summary of the liability component of the Convertible Notes Schedule of Liability Components of Debt Instruments [Table Text Block] Tabular disclosure of the carrying amounts of the liability components of debt instruments. Subsequent Events [Abstract] Subsequent Event [Table] Subsequent Event [Table] Debt Instrument [Axis] Debt Instrument [Axis] Debt Instrument, Name [Domain] Debt Instrument, Name [Domain] Convertible Senior Notes 2.5% And Convertible Senior Notes 5.0% Convertible Senior Notes 2.5% And Convertible Senior Notes 5.0% [Member] Convertible Senior Notes 2.5% And Convertible Senior Notes 5.0% [Member] 2.5% Convertible Notes debt 2021 Convertible Senior Notes, 2.5% [Member] Convertible Senior Notes, 2.5% [Member] Convertible senior notes Subsequent Event Type [Axis] Subsequent Event Type [Axis] Subsequent Event Type [Domain] Subsequent Event Type [Domain] Subsequent Event Subsequent Event [Member] Subsequent Event [Line Items] Subsequent Event [Line Items] Tender offer to repurchase debt Debt Instrument, Tender Offer To Repurchase Debt Debt Instrument, Tender Offer To Repurchase Debt Repurchased aggregate principal amount Debt Instrument, Repurchased Face Amount Notes remaining Commitments and Contingencies Disclosure [Abstract] Long-term Purchase Commitment [Table] Long-term Purchase Commitment [Table] Manufacturing Manufacturing [Member] Manufacturing [Member] Consulting Services Consulting Services [Member] Consulting Services [Member] Long-term Purchase Commitment [Line Items] Long-term Purchase Commitment [Line Items] Non-cancelable purchase obligations Purchase Obligation Number of operating segments Number of Operating Segments Collaborative Arrangement and Arrangement Other than Collaborative [Axis] Collaborative Arrangement and Arrangement Other than Collaborative [Axis] Collaborative Arrangement and Arrangement Other than Collaborative [Domain] Collaborative Arrangement and Arrangement Other than Collaborative [Domain] Commercialization Agreement And Amended Commercialization Agreement Commercialization Agreement And Amended Commercialization Agreement [Member] Commercialization Agreement And Amended Commercialization Agreement [Member] Collegium Pharmaceutical Inc Collegium Pharmaceutical Inc [Member] Represents information pertaining to the license and service agreement with collegium Pharmaceutical Inc. Royalties and milestones Royalties And Milestones [Member] Royalties And Milestones [Member] Total revenues Revenue from Contract with Customer, Excluding Assessed Tax Contract asset, amortization Capitalized Contract Cost, Amortization Expense related to third-party royalties Revenue Recognition, Third-Party Royalty Net Expense Revenue Recognition, Third-Party Royalty Net Expense Business Combinations [Abstract] ACQUISITIONS AND DISPOSITIONS Business Combination And Disposition Disclosure [Text Block] Business Combination And Disposition Disclosure [Text Block] Restructuring and Related Activities [Abstract] Schedule of Restructuring and Related Costs [Table] Schedule of Restructuring and Related Costs [Table] Restructuring Type [Axis] Restructuring Type [Axis] Type of Restructuring [Domain] Type of Restructuring [Domain] Employee Severance and Benefits Employee Severance [Member] Restructuring Plan [Axis] Restructuring Plan [Axis] Restructuring Plan [Domain] Restructuring Plan [Domain] 2019 Cost Savings Initiative 2019 Cost Savings Initiative [Member] 2019 Cost Savings Initiative [Member] Restructuring Cost and Reserve [Line Items] Restructuring Cost and Reserve [Line Items] Restructuring charges Restructuring Charges Accrued restructuring liability Restructuring Reserve, Current Fair Value Disclosures [Abstract] Fair Value, Recurring and Nonrecurring [Table] Fair Value, Recurring and Nonrecurring [Table] Measurement Frequency [Axis] Measurement Frequency [Axis] Measurement Frequency [Domain] Measurement Frequency [Domain] Recurring Fair Value, Recurring [Member] Fair Value Hierarchy and NAV [Axis] Fair Value Hierarchy and NAV [Axis] Fair Value Hierarchy and NAV [Domain] Fair Value Hierarchy and NAV [Domain] Level 1 Fair Value, Inputs, Level 1 [Member] Level 2 Fair Value, Inputs, Level 2 [Member] Level 3 Fair Value, Inputs, Level 3 [Member] Cash and Cash Equivalents [Axis] Cash and Cash Equivalents [Axis] Cash and Cash Equivalents [Domain] Cash and Cash Equivalents [Domain] Collegium warrants Warrant [Member] Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Assets: Assets, Fair Value Disclosure [Abstract] Investments, net Investments Total Assets, Fair Value Disclosure Schedule of accrued restructuring and severance costs Schedule of Restructuring Reserve by Type of Cost [Table Text Block] Schedule of Long-term Debt Instruments [Table] Schedule of Long-term Debt Instruments [Table] Debt Instrument [Line Items] Debt Instrument [Line Items] Contractual interest expense Interest Expense, Debt, Excluding Amortization Amortization of debt discount and debt issuance costs Amortization of Debt Issuance Costs and Discounts Total interest expense Senior Notes Interest Expense, Debt Receivables [Abstract] Allowance for cash discounts for prompt payment Accounts Receivable, Allowance For Cash Discount Accounts Receivable, Allowance For Cash Discount Disposal Groups, Including Discontinued Operations [Table] Disposal Groups, Including Discontinued Operations [Table] Disposal Group Name [Axis] Disposal Group Name [Axis] Disposal Group Name [Domain] Disposal Group Name [Domain] NUCYNTA NUCYNTA [Member] NUCYNTA [Member] Disposal Group Classification [Axis] Disposal Group Classification [Axis] Disposal Group Classification [Domain] Disposal Group Classification [Domain] Disposal Group, Disposed of by Sale, Not Discontinued Operations Disposal Group, Disposed of by Sale, Not Discontinued Operations [Member] Third-Party Consent Agreement Third-Party Consent Agreement [Member] Third-Party Consent Agreement [Member] Scenario [Axis] Scenario [Axis] Scenario [Domain] Scenario [Domain] Forecast Forecast [Member] Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] Consideration received, including base purchase price, inventory adjustment and royalties received Disposal Group, Including Discontinued Operation, Consideration, Including Base Purchase Price And Inventory Adjustment Disposal Group, Including Discontinued Operation, Consideration, Including Base Purchase Price And Inventory Adjustment Proceeds from divestiture of businesses, base purchase price Disposal Group, Including Discontinued Operation, Consideration, Base Purchase Price Disposal Group, Including Discontinued Operation, Consideration, Base Purchase Price Proceeds from divestiture of businesses, inventory amount Disposal Group, Including Discontinued Operations, Inventory Adjustment Disposal Group, Including Discontinued Operations, Inventory Adjustment Royalties received Disposal Group, Including Discontinued Operations, Royalties Received Disposal Group, Including Discontinued Operations, Royalties Received Number of lump sum payments Disposal Group, Lump Sum Payment Obligation, Number Of Payments Disposal Group, Lump Sum Payment Obligation, Number Of Payments Lump sum payments obligation Disposal Group, Annual Lump Sum Payment Due In Years Two And Three Disposal Group, Annual Lump Sum Payment Due In Years Two And Three Gain (loss) on disposal Disposal Group, Not Discontinued Operation, Gain (Loss) on Disposal Consideration received Disposal Group, Including Discontinued Operations, Upfront Consideration Received Disposal Group, Including Discontinued Operations, Upfront Consideration Received Contingent consideration deemed to be probable Disposal Group, Including Discontinued Operations, Contingent Consideration Deemed Probable Disposal Group, Including Discontinued Operations, Contingent Consideration Deemed Probable Accrued third-party consent fees Disposal Group, Including Discontinued Operations, Accrued Third-Party Consent Fees Disposal Group, Including Discontinued Operations, Accrued Third-Party Consent Fee Carrying value of intangible derecognized Disposal Group, Including Discontinued Operations, Carrying Value, Intangible Derecognized Disposal Group, Including Discontinued Operations, Carrying Value, Intangible Derecognized Inventory transfer Disposal Group, Including Discontinued Operations, Inventory Transfer Disposal Group, Including Discontinued Operations, Inventory Transfer Cover [Abstract] Document Type Document Type Document Quarterly Report Document Quarterly Report Document Period End Date Document Period End Date Document Transition Report Document Transition Report Entity File Number Entity File Number Entity Registrant Name Entity Registrant Name Entity Incorporation, State or Country Code Entity Incorporation, State or Country Code Entity Tax Identification Number Entity Tax Identification Number Entity Address, Address Line One Entity Address, Address Line One Entity Address, Address Line Two Entity Address, Address Line Two Entity Address, City or Town Entity Address, City or Town Entity Address, State or Province Entity Address, State or Province Entity Address, Postal Zip Code Entity Address, Postal Zip Code City Area Code City Area Code Local Phone Number Local Phone Number Title of 12(b) Security Title of 12(b) Security Trading Symbol Trading Symbol Security Exchange Name Security Exchange Name Entity Current Reporting Status Entity Current Reporting Status Entity Interactive Data Current Entity Interactive Data Current Entity Filer Category Entity Filer Category Entity Smaller Reporting Company Entity Small Business Entity Emerging Growth Company Entity Emerging Growth Company Entity Shell Company Entity Shell Company Entity Common Stock, Shares Outstanding (in shares) Entity Common Stock, Shares Outstanding Entity Central Index Key Entity Central Index Key Amendment Flag Amendment Flag Current Fiscal Year End Date Current Fiscal Year End Date Document Fiscal Year Focus Document Fiscal Year Focus Document Fiscal Period Focus Document Fiscal Period Focus Leases [Abstract] Schedule of lease cost components, Cash Flow information, and term and discount rate information Lease, Cost [Table Text Block] Goodwill and Intangible Assets Disclosure [Abstract] Schedule of the gross carrying amounts and net book values of our intangible assets Schedule of Finite-Lived Intangible Assets [Table Text Block] Schedule of the future amortization expenses of intangible assets Schedule of Finite-Lived Intangible Assets, Future Amortization Expense [Table Text Block] Schedule of Finite-Lived Intangible Assets [Table] Schedule of Finite-Lived Intangible Assets [Table] Finite-Lived Intangible Assets by Major Class [Axis] Finite-Lived Intangible Assets by Major Class [Axis] Finite-Lived Intangible Assets, Major Class Name [Domain] Finite-Lived Intangible Assets, Major Class Name [Domain] Product rights Product Rights [Member] Legal rights held to use a product. Finite-Lived Intangible Assets [Line Items] Finite-Lived Intangible Assets [Line Items] Amortization of intangible assets Amortization of Intangible Assets Write-off of remaining carrying value, disposition Disposal Of Intangible Assets, Finite-lived Disposal Of Intangible Assets, Finite-lived Business Acquisition [Axis] Business Acquisition [Axis] Business Acquisition, Acquiree [Domain] Business Acquisition, Acquiree [Domain] NUCYNTA Janssen Nucynta [Member] Represents activity related to NUCYNTA and related inventory. Variable Rate [Axis] Variable Rate [Axis] Variable Rate [Domain] Variable Rate [Domain] Three month LIBOR London Interbank Offered Rate (LIBOR) [Member] 5.0% Convertible Notes debt 2024 Convertible Senior Notes, 5.0% [Member] Convertible Senior Notes, 5.0% [Member] Equity Components [Axis] Equity Components [Axis] Equity Component [Domain] Equity Component [Domain] Common Stock Common Stock [Member] Aggregate principal amount Debt Instrument, Face Amount Proceeds from the issuance of debt Proceeds from Issuance of Debt Basis spread Debt Instrument, Basis Spread on Variable Rate Interest rate Debt Instrument, Interest Rate, Stated Percentage Interest rate through third anniversary of purchase date Debt Instrument, Interest Rate Through Third Anniversary, Percentage Maximum contractual interest rate for funds borrowed, under the debt agreement through third anniversary of the purchase date. Interest rate after third anniversary of purchase date Debt Instrument, Interest Rate After Third Anniversary, Percentage Maximum contractual interest rate for funds borrowed, under the debt agreement after third anniversary of the purchase date Effective interest rate Debt Instrument, Interest Rate, Effective Percentage Payment of debt extinguishment Payment for Debt Extinguishment or Debt Prepayment Cost Payment accrued exit fees Payment For Debt Exit Fee Payment For Debt Exit Fee Loss on extinguishment of convertible notes Gain (Loss) on Extinguishment of Debt Debt prepayment fee Payment Of Debt Prepayment Cost Payment Of Debt Prepayment Cost Unamortized balances of debt discount and debt issuance costs Debt Instrument, Unamortized Discount (Premium) and Debt Issuance Costs, Net Debt extinguishment, amount Extinguishment of Debt, Amount Extinguishment of debt, cash paid Extinguishment Of Debt, Cash Paid Extinguishment Of Debt, Cash Paid Reduction in carrying amount of equity component Debt Instrument, Convertible, Increase (Decrease) In Carrying Amount Of Equity Component Debt Instrument, Convertible, Increase (Decrease) In Carrying Amount of Equity Component Accretion of debt discount and debt issuance costs Carrying amount of equity component Debt Instrument, Convertible, Carrying Amount of Equity Component Extinguishment of debt, shares issued (in shares) Stock Issued During Period, Shares, New Issues Reacquisition in additional paid-in capital, equity component Adjustments to Additional Paid in Capital, Equity Component of Convertible Debt Stock price trigger Debt Instrument, Convertible, Threshold Percentage of Stock Price Trigger Conversion price (in dollars per share) Debt Instrument, Convertible, Conversion Price Business days, period Debt Instrument Convertible Threshold Business Days Threshold period of specified business days within which the maximum product of the closing sale price of shares of the entity's common stock and the applicable conversion rate for such trading day triggers the conversion feature. Consecutive trading-day period Debt Instrument Convertible Threshold Consecutive Trading Day Period Threshold period of specified consecutive trading days within which the maximum product of the closing sale price of shares of the entity's common stock and the applicable conversion rate for such trading day triggers the conversion feature. Conversion ratio Debt Instrument, Convertible, Conversion Ratio Earnings Per Share [Abstract] NET INCOME (LOSS) PER SHARE Earnings Per Share [Text Block] Inventory Disclosure [Abstract] Inventory Inventory, Net [Abstract] Raw materials Inventory, Raw Materials, Gross Work-in-process Inventory, Work in Process, Gross Finished goods Inventory, Finished Goods, Gross Total Schedule of inventories, net Schedule of Inventory, Current [Table Text Block] 2020 (remainder) Finite-Lived Intangible Assets, Amortization Expense, Remainder of Fiscal Year 2021 Finite-Lived Intangible Assets, Amortization Expense, Year Two 2022 Finite-Lived Intangible Assets, Amortization Expense, Year Three Thereafter Finite-Lived Intangible Assets, Amortization Expense, After Year Three Finite-Lived Intangible Assets, Amortization Expense, After Year Three Total Finite-Lived Intangible Assets, Net Schedule of Business Acquisitions by Acquisition, Equity Interest Issued or Issuable [Table] Schedule of Business Acquisitions by Acquisition, Equity Interest Issued or Issuable [Table] Zyla Life Sciences Zyla Life Sciences [Member] Zyla Life Sciences [Member] Legal Entity [Axis] Legal Entity [Axis] Entity [Domain] Entity [Domain] Parent Assertio, Parent [Member] Assertio, Parent [Member] Class of Stock [Axis] Class of Stock [Axis] Class of Stock [Domain] Class of Stock [Domain] Business Acquisition, Equity Interests Issued or Issuable [Line Items] Business Acquisition, Equity Interests Issued or Issuable [Line Items] Par value of common stock (in dollars per share) Common Stock, Par or Stated Value Per Share Exchange ratio (in shares) Business Acquisition, Equity Interest Issued Or Issuable, Share Exchange Ratio Business Acquisition, Equity Interest Issued Or Issuable, Share Exchange Ratio DEBT Long-term Debt [Text Block] Stock Options Share-based Payment Arrangement, Option [Member] Restricted Stock Units and Performance-based Restricted Stock Units Restricted Stock Units And Performance Based Restricted Stock Units [Member] Restricted Stock Units And Performance Based Restricted Stock Units [Member] RSUs Restricted Stock Units (RSUs) [Member] PSUs Total unrecognized compensation expense Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount Average vesting period for recognition of unrecognized compensation expense Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition Total unrecognized compensation expense, non-options Share-based Payment Arrangement, Nonvested Award, Excluding Option, Cost Not yet Recognized, Amount Award granted (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period Granted (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value Options granted (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross Schedule of revenue from contracts with customers Revenue from External Customers by Products and Services [Table Text Block] Summary of contract assets and liabilities Contract with Customer, Asset and Liability [Table Text Block] Schedule of accounts receivables, net Schedule of Accounts, Notes, Loans and Financing Receivable [Table Text Block] STOCK-BASED COMPENSATION Share-based Payment Arrangement [Text Block] Statement of Stockholders' Equity [Abstract] Additional Paid-In Capital Additional Paid-in Capital [Member] Accumulated Earnings (Deficit) Retained Earnings [Member] Accumulated Other Comprehensive Loss AOCI Attributable to Parent [Member] Increase (Decrease) in Stockholders' Equity Increase (Decrease) in Stockholders' Equity [Roll Forward] Balances (in shares) Common Stock, Shares, Issued Balances Issuance of common stock upon exercise of options (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period Issuance of common stock upon exercise of options Stock Issued During Period, Value, Stock Options Exercised Issuance of common stock in conjunction with vesting of restricted stock units (in shares) Stock Issued During Period, Shares, Restricted Stock Award, Net of Forfeitures Reacquisition of equity component of 2021 Notes and 2024 Notes Stock-based compensation APIC, Share-based Payment Arrangement, Increase for Cost Recognition Shares withheld for payment of employee's withholding tax liability Share-based Payment Arrangement, Decrease for Tax Withholding Obligation Net income (loss) Net Income (Loss) Attributable to Parent Balances (in shares) Balances Intangible assets Remaining Useful Life (In years) Finite-Lived Intangible Asset, Useful Life Gross Carrying Amount Finite-Lived Intangible Assets, Gross Accumulated Amortization Finite-Lived Intangible Assets, Accumulated Amortization Disposition Impairment Impairment of Intangible Assets, Finite-lived New Accounting Pronouncements or Change in Accounting Principle [Table] New Accounting Pronouncements or Change in Accounting Principle [Table] New Accounting Pronouncements or Change in Accounting Principle [Line Items] New Accounting Pronouncements or Change in Accounting Principle [Line Items] Investment, long-term loan receivable Financing Receivable, before Allowance for Credit Loss Expected allowance for credit loss Financing Receivable, Expected Allowance For Credit Loss Financing Receivable, Expected Allowance For Credit Loss Reacquisition of equity component Principal amount of the Notes Long-term Debt, Gross Unamortized discount of the liability component Debt Instrument, Unamortized Discount Unamortized debt issuance costs Unamortized Debt Issuance Expense Total Senior Notes, Noncurrent Schedule of fair value hierarchy for financial assets and liabilities measured at fair value on a recurring basis Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block] SUBSEQUENT EVENTS Subsequent Events [Text Block] Lessee, Lease, Description [Table] Lessee, Lease, Description [Table] Income Statement Location [Axis] Income Statement Location [Axis] Income Statement Location [Domain] Income Statement Location [Domain] Selling, general and administrative expenses Selling, General and Administrative Expenses [Member] Other Other Expense (Income), Net [Member] Other Expense (Income), Net [Member] Lessee, Lease, Description [Line Items] Lessee, Lease, Description [Line Items] Operating lease cost Operating Lease, Cost Total lease cost Lease, Cost Sublease Income Sublease Income Income Tax Disclosure [Abstract] INCOME TAXES Income Tax Disclosure [Text Block] REVENUE Revenue from Contract with Customer [Text Block] Inventory reserves Inventory Valuation Reserves Income Statement [Abstract] Product sales, net Product [Member] Commercialization agreement, net Commercialization Agreement [Member] Represents information pertaining to the commercialization agreement. Revenues: Revenues [Abstract] Costs and expenses: Operating Costs and Expenses [Abstract] Cost of sales (excluding amortization of intangible assets) Cost of Goods and Service, Excluding Depreciation, Depletion, and Amortization Research and development expenses Research and Development Expense (Excluding Acquired in Process Cost) Selling, general and administrative expenses Selling, General and Administrative Expense Total costs and expenses Costs and Expenses (Loss) income from operations Operating Income (Loss) Other income (expense): Nonoperating Income (Expense) [Abstract] Gain (loss) on sale of assets Gain (Loss) on Disposition of Assets Loss on extinguishment of convertible notes Interest expense Interest Expense Loss on prepayment of Senior Notes Loss On Debt Prepayment Loss On Debt Prepayment Other Other Nonoperating Income (Expense) Total other income (expense) Nonoperating Income (Expense) Net income (loss) before income taxes Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest Income tax expense Income Tax Expense (Benefit) Net income (loss) Comprehensive income (loss) Comprehensive Income (Loss), Net of Tax, Attributable to Parent Basic net income (loss) per share (in dollars per share) Earnings Per Share, Basic Diluted net income (loss) per share (in dollars per share) Earnings Per Share, Diluted Shares used in computing basic net income (loss) per share (in shares) Weighted Average Number of Shares Outstanding, Basic Shares used in computing diluted net income (loss) per share (in shares) Weighted Average Number of Shares Outstanding, Diluted ACCRUED LIABILITIES Accounts Payable and Accrued Liabilities Disclosure [Text Block] Employee compensation costs Accrued restructuring and severance costs rollforward Restructuring Reserve [Roll Forward] Balance at beginning of period Cash paid Payments for Restructuring Balance at end of period Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table] Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table] Antidilutive Securities [Axis] Antidilutive Securities [Axis] Antidilutive Securities, Name [Domain] Antidilutive Securities, Name [Domain] Stock options, awards and equivalents Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] Basic net income (loss) per share Earnings Per Share, Basic [Abstract] Net income (loss) Weighted average common shares outstanding (in shares) Basic net (loss) income per share (in dollars per share) Diluted net income (loss) per share Earnings Per Share, Diluted [Abstract] Add: effect of dilutive stock options, awards, and equivalents (in shares) Weighted Average Number Diluted Shares Outstanding Adjustment Denominator for diluted income (loss) per share (in shares) Diluted net (loss) income per share (in dollars per share) Potentially dilutive common shares: Dilutive Securities, Effect on Basic Earnings Per Share [Abstract] Total potentially dilutive common shares (in shares) Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Revenue, Initial Application Period Cumulative Effect Transition [Table] Revenue, Initial Application Period Cumulative Effect Transition [Table] Adjustments for New Accounting Pronouncements [Axis] Adjustments for New Accounting Pronouncements [Axis] Type of Adoption [Domain] Type of Adoption [Domain] ASU 2014-09 Accounting Standards Update 2014-09 [Member] Initial Application Period Cumulative Effect Transition [Axis] Initial Application Period Cumulative Effect Transition [Axis] Initial Application Period Cumulative Effect Transition [Domain] Initial Application Period Cumulative Effect Transition [Domain] Adjustments Difference between Revenue Guidance in Effect before and after Topic 606 [Member] Revenue, Initial Application Period Cumulative Effect Transition [Line Items] Revenue, Initial Application Period Cumulative Effect Transition [Line Items] Gain Contingencies [Table] Gain Contingencies [Table] Litigation Case [Axis] Litigation Case [Axis] Litigation Case [Domain] Litigation Case [Domain] Securities Class Action Lawsuit and Related Matters Securities Class Action Lawsuit [Member] Represents information related to the securities calss action lawsuits. Multidistrict Opioid Litigation Multidistrict Opioid Litigation [Member] Information pertaining to Multidistrict Opioid Litigation. Legal matters Gain Contingencies [Line Items] Number of shareholder derivative actions filed Number of Shareholder Derivative Actions Filed Represents the number of shareholder derivative actions that were filed. Number of industry-wide opioid litigation cases (more than) Claims, Number, Industry-Wide Number of claims filed industry-wide. Contract asset - Collegium, net Contract With Customer, Asset [Roll Forward] Contract With Customer, Asset [Roll Forward] Contract With Customer, Asset [Roll Forward] Contract asset, Beginning of Period Contract with Customer, Asset, after Allowance for Credit Loss Additions Contract with Customer Asset Net Current Additions The amount of additions, in right to consideration in exchange for good or service transferred to customer when right is conditioned on something other than passage of time. Deductions Contract with Customer, Asset, Deletions Amount of decrease in right to consideration in exchange for good or service transferred to customer when right is conditioned on something other than passage of time, from business combination. May include payments received during the period. Contract asset, End of Period Contract liability Contract with Customer, Liability Proceeds from issuance of warrants Proceeds from Issuance of Warrants FAIR VALUE Fair Value Disclosures [Text Block] Number of subleases Lessee, Operating Lease, Number Of Subleases Lessee, Operating Lease, Number Of Subleases Operating lease, number of renewal options Lessee, Operating Lease, Number Of Renewal Options Lessee, Operating Lease, Number Of Renewal Options Lease term Lessee, Operating Lease, Term of Contract Expense from income taxes Effective tax rate Effective Income Tax Rate Reconciliation, Percent Federal statutory rate Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent Accrued interest and penalties associated with unrecognized tax benefits Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued Stated coupon interest Statement of Cash Flows [Abstract] Operating Activities Net Cash Provided by (Used in) Operating Activities, Continuing Operations [Abstract] Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Gain (Loss) on sale of assets Gain (Loss) on Disposition of Intangible Assets Loss on prepayment of Senior Notes Depreciation and amortization Depreciation, Depletion and Amortization Recurring fair value measurement of assets and liabilities Fair Value Adjustment Of Assets And Liabilities Fair Value Adjustment Of Assets And Liabilities Stock-based compensation Share-based Payment Arrangement, Noncash Expense Provision for inventory and other assets Provision For Inventory And Other Assets Provision For Inventory And Other Assets Other Other Noncash Income (Expense) Changes in assets and liabilities: Increase (Decrease) in Operating Capital [Abstract] Accounts receivable Increase (Decrease) in Accounts Receivable Inventories Increase (Decrease) in Inventories Prepaid and other assets Increase (Decrease) in Prepaid Expense and Other Assets Accounts payable and other accrued liabilities Increase (Decrease) in Accounts Payable and Accrued Liabilities Excluding Employee Related Liabilities The increase (decrease) during the reporting period in the amounts payable to vendors for goods and services received and the amount of obligations and expenses incurred but not paid. Excludes employee related liabilities. Accrued rebates, returns and discounts Increase (Decrease) in Accrued Rebates, Returns and Discounts The increase (decrease) during the reporting period related to rebates, returns and discounts incurred but not paid. Interest payable Increase (Decrease) in Interest Payable, Net Net cash (used in) provided by operating activities Net Cash Provided by (Used in) Operating Activities Investing Activities Net Cash Provided by (Used in) Investing Activities, Continuing Operations [Abstract] Purchases of property and equipment Payments to Acquire Property, Plant, and Equipment Proceeds from sale of assets Proceeds from Sale of Productive Assets Net cash provided by (used in) investing activities Net Cash Provided by (Used in) Investing Activities Financing Activities Net Cash Provided by (Used in) Financing Activities, Continuing Operations [Abstract] Payments in connection with debt payment Proceeds from issuance of common stock Proceeds from Issuance of Common Stock Shares withheld for payment of employee's withholding tax liability Payment, Tax Withholding, Share-based Payment Arrangement Net cash used in financing activities Net Cash Provided by (Used in) Financing Activities Net increase (decrease) in cash and cash equivalents Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect Cash and cash equivalents at beginning of year Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents Cash and cash equivalents at end of period Supplemental Disclosure of Cash Flow Information Supplemental Cash Flow Information [Abstract] Net cash paid for income taxes Income Taxes Paid, Net Cash paid for interest Interest Paid, Excluding Capitalized Interest, Operating Activities Capital expenditures incurred but not yet paid Capital Expenditures Incurred but Not yet Paid Schedule of accrued liabilities Schedule of Accounts Payable and Accrued Liabilities [Table Text Block] Amended Commercialization Agreement Amended Commercialization Agreement [Member] Amended Commercialization Agreement [Member] Collaborative Arrangement and Arrangement Other than Collaborative [Line Items] Warrant, number of shares (in shares) Class of Warrant or Right, Number of Securities Called by Warrants or Rights Warrant, exercise price per share (in dollars per share) Class of Warrant or Right, Exercise Price of Warrants or Rights Warrant, exercise period Class Of Warrant Or Right, Exercise Period Class Of Warrant Or Right, Exercise Period Warrants outstanding Warrants and Rights Outstanding Disaggregation of Revenue [Table] Disaggregation of Revenue [Table] Total neurology product sales, net Neurology Product [Member] Neurology product. NUCYNTA and Lazanda product sales adjustments Commercialization agreement, net Commercialization Rights And Facilitation Services [Member] Pertaining to commercialization rights and facilitation services. Royalties and milestone revenue Disaggregation of Revenue [Line Items] Disaggregation of Revenue [Line Items] Principal amount of the Senior Notes Unamortized debt discount balance Unamortized debt issuance costs Schedule of Cash and Cash Equivalents and Marketable Securities [Table] Schedule of Cash and Cash Equivalents and Marketable Securities [Table] Schedule of cash and cash equivalent balances and investments in marketable securities. Receivables from Collegium Measurement Basis [Axis] Measurement Basis [Axis] Fair Value Measurement [Domain] Fair Value Measurement [Domain] Portion at Fair Value Measurement Portion at Fair Value Measurement [Member] Fair Value Estimate of Fair Value Measurement [Member] Level 2 Schedule of Cash and Cash Equivalents and Marketable Securities [Line Items] Schedule of Cash and Cash Equivalents and Marketable Securities [Line Items] 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. Warrant, fair value price (in dollars per share) Class Of Warrant Or Right, Fair Value Price Of Warrants Or Rights Class Of Warrant Or Right, Fair Value Price Of Warrants Or Rights Warrant, expected term Class Of Warrant Or Right, Expected Term Class Of Warrant Or Right, Expected Term Warrant, risk-free rate Class Of Warrant Or Right, Risk-Free Rate Class Of Warrant Or Right, Risk-Free Rate Warrant, remaining contractual period Class Of Warrant Or Right, Remaining Contractual Period Class Of Warrant Or Right, Remaining Contractual Period Fair value adjustment, recorded loss Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings Estimated fair value of debt Debt Instrument, Fair Value Disclosure Par value of debt Schedule of Accounts, Notes, Loans and Financing Receivable [Table] Schedule of Accounts, Notes, Loans and Financing Receivable [Table] Receivable Type [Axis] Receivable Type [Axis] Receivable [Domain] Receivable [Domain] Receivables related to product sales, net Product Sales Receivable [Member] Product Sales Receivable [Member] Other Collaborative Partners Receivable [Member] Collaborative Partners Receivable [Member] ACCOUNTS RECEIVABLES, NET Accounts, Notes, Loans and Financing Receivable [Line Items] Accounts receivables Accounts Receivable, after Allowance for Credit Loss [Abstract] Accounts receivables, net INVENTORIES, NET Inventory Disclosure [Text Block] COMMITMENTS AND CONTINGENCIES Commitments and Contingencies Disclosure [Text Block] Schedule of calculation of basic and diluted earnings per common share Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Schedule of anti-dilutive securities excluded from computation of diluted net (loss) income per share Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table Text Block] Share-based Payment Arrangement, Expensed and Capitalized, Amount [Table] Share-based Payment Arrangement, Expensed and Capitalized, Amount [Table] Cost of sales Cost of Sales [Member] Research and development expense Research and Development Expense [Member] Selling, general and administrative expense Restructuring Restructuring Charges [Member] Stock-based compensation Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items] Total Share-based Payment Arrangement, Expense INTANGIBLE ASSETS Intangible Assets Disclosure [Text Block] Sale of disposal group, total value Disposal Group, Including Discontinued Operation, Consideration Sale of disposal group, cash received Proceeds from Divestiture of Businesses Consideration receivable as percentage of net sales after closing Disposal Group, Including Discontinued Operations, Consideration, Percentage Of Net Sales After Closing Disposal Group, Including Discontinued Operations, Consideration, Percentage Of Net Sales After Closing Threshold for consideration receivable on net sales after closing Disposal Group, Including Discontinued Operation, Consideration, Threshold For Net Sales After Closing Disposal Group, Including Discontinued Operation, Consideration, Threshold For Net Sales After Closing Consideration received, including base purchase price and inventory adjustment Consideration received, base purchase price Consideration received, inventory adjustment upon disposal Net sale after closing, contingent consideration Disposal Group, Including Discontinued Operation, Consideration, Amount Of Net Sales After Closing Disposal Group, Including Discontinued Operation, Consideration, Amount Of Net Sales After Closing Recognized gain Upfront consideration received Co-promotion service income RESTRUCTURING CHARGES Restructuring, Impairment, and Other Activities Disclosure [Text Block] License Agreement License Agreement [Member] Pertaining to the license agreement. Asset Acquisition [Axis] Asset Acquisition [Axis] Asset Acquisition [Axis] Asset Acquisition [Domain] Asset Acquisition [Domain] [Domain] for Asset Acquisition [Axis] Slan Slan [Member] This member stands for the information related to Slan and cosyntropin. License fee received in cash License Fee The amount of the license fee incurred during the period. Term of license agreement Collaborative Agreement, Term Of License Agreement The period of time the license agreement last following the first commercial sale in the U.S. Reimbursable development expenses Reimbursable Development Expenses Reimbursable Development Expenses Reimbursable development expenses, received Collaborative Arrangement, Termination, Reimbursable Development Expenses Received Collaborative Arrangement, Termination, Reimbursable Development Expenses Received Possible future payments to be received, based upon commercial sales, if circumstances met Collaborative Arrangement, Termination, Future Payments To Be Received, If Circumstances Met Collaborative Arrangement, Termination, Future Payments To Be Received, If Circumstances Met ACCOUNTS RECEIVABLES, NET Loans, Notes, Trade and Other Receivables Disclosure [Text Block] LEASES Lessor, Operating Leases [Text Block] LEASES Lessee, Operating Leases [Text Block]