Document And Entity Information Note To Financial Statement Details Textual statementsignificantaccountingpoliciespolicies statementnote2investmentsandfairvaluemeasurementtables statementnote3inventoriestables statementnote5collaborationagreementtables statementnote7liabilityrelatedtosaleoffutureroyaltiestables statementnote9stockbasedcompensationtables statementnote10netlosspershareofcommonstocktables statementnote2investmentsandfairvaluemeasurementsummaryofcashcashequivalentsandinvestmentsdetails us-gaap_DeferredRevenue Deferred Revenue statementnote2investmentsandfairvaluemeasurementfairvalueoffinancialassetsandliabilitiesbylevelwithinfairvaluehierarchydetails statementnote2investmentsandfairvaluemeasurementassumptionsusedinblackscholesoptionpricingmodeltoestimatefairvalueofpipewarrantsdetails statementnote2investmentsandfairvaluemeasurementsummaryofchangesinfairvalueofleveliiifinancialliabilitiesdetails statementnote3inventoriesinventorycomponentsdetails us-gaap_Revenues Total revenue statementnote5collaborationagreementasummaryofrevenuerecognizedundertheamendedagreementsdetails statementnote7liabilityrelatedtosaleoffutureroyaltiesactivityofliabilityrelatedtosaleoffutureroyaltiesdetails statementnote9stockbasedcompensationstockbasedcompensationexpensedetails statementnote10netlosspershareofcommonstockcomputationofbasicanddilutednetlosspershareofcommondetails statementnote10netlosspershareofcommonstockoutstandingsharesofcommonstockequivalentsexcludedfromcomputationofdilutednetlosspersharedetails Fair Value Notes To Financial Statements Notes To Financial Statements [Abstract] acrx_AwardContractRenewalTerm Award Contract Renewal Term Term of the award contract renewal, in 'PnYnMnDTnHnMnS' format. Fair Value, Inputs, Level 2 [Member] Fair Value, Inputs, Level 1 [Member] Fair Value, Inputs, Level 3 [Member] us-gaap_LineOfCredit Long-term Line of Credit Fair Value Hierarchy [Domain] Fair Value, Hierarchy [Axis] Cash flows from investing activities: Long-term Debt [Text Block] Equity Component [Domain] Equity Components [Axis] acrx_DebtInstrumentFinalPaymentPercentageOfAggregatePrincipalAmount Debt Instrument, Final Payment, Percentage of Aggregate Principal Amount The final payment, expressed as a percentage of aggregate principal amount, under a debt agreement. acrx_DebtInstrumentMinimumTriggerAmountToExtendPeriodOfInterestOnlyPayments Debt Instrument, Minimum Trigger Amount to Extend Period of Interest Only Payments Represents the minimum amount of net proceeds to extend the period of interest only payments. Cash [Member] Cash and Cash Equivalents [Domain] us-gaap_IncreaseDecreaseInDeferredRevenue Deferred revenue us-gaap_ComprehensiveIncomeNetOfTax Comprehensive loss Cash and Cash Equivalents [Axis] us-gaap_IncreaseDecreaseInAccruedLiabilities Accrued liabilities Use of Estimates, Policy [Policy Text Block] Common stock, outstanding (in shares) us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity Line of Credit Facility, Maximum Borrowing Capacity acrx_DebtInstrumentVariableRateThreshold Debt Instrument, Variable Rate Threshold Represents the percentage of variable rate threshold used to determine the interest rate under the debt agreement. If the reference rate is above this percentage threshold, the interest rate equals to the minimum stated rate plus the difference between the reference rate and the threshold. If the reference rate is below this percentage threshold, the interest rate equals to the minimum stated rate. New Accounting Pronouncements, Policy [Policy Text Block] Asset Class [Axis] Cash and Cash Equivalents [Member] Asset Class [Domain] Shares used in computing net loss per share of common stock, diluted – see Note 10 (in shares) Diluted (in shares) Shares of common stock equivalents excluded from the computation of diluted net loss per share of common stock (in shares) us-gaap_IncreaseDecreaseInAccountsPayable Accounts payable us-gaap_AvailableForSaleSecuritiesAccumulatedGrossUnrealizedLossBeforeTax Gross Unrealized Losses Market Price (in dollars per share) Gross Unrealized Gains us-gaap_GovernmentContractReceivable Government Contract Receivable Amortized Cost Consolidation, Policy [Policy Text Block] Net loss per share of common stock, diluted (in dollars per share) Restricted cash Cash and cash equivalents Cash and cash equivalents—Beginning of period Cash and cash equivalents—End of period us-gaap_RepaymentsOfLongTermDebt Repayments of Long-term Debt us-gaap_DebtConversionConvertedInstrumentWarrantsOrOptionsIssued1 Debt Conversion, Converted Instrument, Warrants or Options Issued Contract and Other Revenue [Member] Represents information about Contract and Other Revenue. Royalty revenue Shares used in computing net loss per share of common stock, basic (in shares) Long-term Contracts or Programs Disclosure [Text Block] Contract and other Contracts Revenue Net loss per share of common stock, basic (in dollars per share) Scenario, Unspecified [Domain] Scenario, Forecast [Member] General and Administrative Expense [Member] acrx_LongTermDebtMaturitiesBalloonPayments Long-term Debt Maturities Balloon Payments Represents the long term debt maturities for balloon payments. us-gaap_IncreaseDecreaseInDeferredLiabilities Deferred rent Scenario [Axis] Expected volatility Cost of Sales [Member] Income Statement Location [Domain] Income Statement Location [Axis] Research and Development Expense [Member] Basis of Accounting, Policy [Policy Text Block] Other (expense) income: Accounting Policies [Abstract] Statement of Financial Position [Abstract] us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets Prepaid expenses and other assets Total liabilities measured at fair value Statement of Cash Flows [Abstract] Fair Value by Liability Class [Domain] Liability Class [Axis] Stock-based compensation expense Government [Member] Products and Services [Domain] Liability related to the sale of future royalties, net of current portion Liability related to sale of future royalties — net of current portion The amount of liability related to sale of future royalties less current portion. Legal Entity Type of Counterparty [Domain] Products and Services [Axis] Contingent put option liability Fair Value Of Contingent Put Option, Liability Represents the fair value of contingent put option liability. Liability related to the sale of future royalties, current portion acrx_SaleOfFutureRoyaltiesLiabilitiesCurrent Less: current portion The current portion of liability related to sale of future royalties. Legal Entity of Counterparty, Type [Axis] Revenue: Collaboration agreement revenue Revenue recognized from collaboration agreements. Other comprehensive (loss) income: us-gaap_IncreaseDecreaseInAccountsReceivable Accounts receivable Non-cash interest expense recognized Non-cash interest expense on liability related to future sale of royalties Non-cash interest expense on liability related to royalty monetization The amount of non-cash interest expense recognized. Europe [Member] Adjustments to reconcile net loss to net cash used in operating activities: Geographical [Domain] acrx_RevaluationOfConvertiblePreferredStockWarrantLiabilityAndWriteoffOfCallOptionLiability Revaluation of put option and PIPE warrant liabilities Revaluation of convertible preferred stock warrant liability and write off of call option liability. Geographical [Axis] Net loss before income taxes acrx_NetProceedsFromIssuanceOfCommonStockAndExerciseOfWarrants Net proceeds from issuance of common stock through equity plans and exercise of warrants Net Proceeds From Issuance Of Common Stock And Exercise Of Warrants Proceeds from sale of future royalties Net proceeds from sale of future royalties. acrx_RoyaltyArrangmentMaximumPayments Royalty Arrangment Maximum Payments The capped amount of payments of company required to make to PDL. us-gaap_LiabilitiesAndStockholdersEquity Total Liabilities and Stockholders’ Deficit acrx_ProceedsFromSaleOfRoyaltyAndMilestoneRights Proceeds From Sale Of Royalty And Milestone Rights The amount of proceeds from the sale of royalty and milestone rights. us-gaap_IncomeTaxExpenseBenefit Provision for income taxes Accumulated deficit acrx_EffectiveAnnualInterestRate Effective Annual Interest Rate Effective annual rate for a liability related to sale of future royalties. us-gaap_OtherThanTemporaryImpairmentLossesInvestmentsAvailableforsaleSecurities Other than Temporary Impairment Losses, Investments, Available-for-sale Securities Accumulated other comprehensive (loss) income acrx_AvailableForSaleSecuritiesGrossUnrealizedGainLossAccumulatedInInvestments Available For Sale Securities, Gross, Unrealized Gain (Loss) Accumulated In Investments Net amount of the difference between the fair value and cost of investments in available for sale securities. Investments And Fair Value Measurement Disclosure [Text Block] The disclosure of investments and fair value measurement. us-gaap_PolicyTextBlockAbstract Accounting Policies us-gaap_IncreaseDecreaseInInventories Inventories us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationsRecurringBasisLiabilityValue Balance, fair value Balance, fair value U.S. Government Agency Securities [Member] Represents the U.S. Government Agency Securities. Change in fair value of contingent put option associated with Amended Loan Agreement Deferred rent, net of current portion Major Types of Debt and Equity Securities [Domain] Statement [Table] Major Types of Debt and Equity Securities [Axis] U.S. Government Agency Obligations [Member] Represents the U.S. Government Agency Obligations. PIPE Warrants [Member] Represents PIPE Warrants. Contingent Put Option Liability [Member] Represents the contingent put option liability. Deferred revenue, net of current portion Deferred Revenue, Noncurrent AUSTRALIA us-gaap_AvailableForSaleSecuritiesGrossRealizedGainLossNet Available-for-sale Securities, Gross Realized Gain (Loss) Fair Value Of Warrants [Table Text Block] Tabular disclosure of the fair value of warrants. Income Statement [Abstract] Cash flows from financing activities: Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block] Hercules 2011 Loan and Security Agreement [Member] Represents the 2011 Hercules loan and security agreement. Change in fair value of PIPE warrants Represents the change in fair value of private placement warrants. Long-term debt, net of current portion us-gaap_LongTermDebtNoncurrent Class of Stock [Axis] Award Type [Axis] Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] acrx_DebtInstrumentPercentageUsedToCalculateVariableRate Debt Instrument, Percentage Used To Calculate Variable Rate The percentage that is used to determine the debt instruments variable rate. Equity Award [Domain] us-gaap_OtherIncome Other Income acrx_IncreaseDecreaseInMilestonePaymentsRelatedToNetSalesTarget Increase (Decrease) In Milestone Payments Related To Net Sales Target The increase (decrease) in milestone payments related to net sales target. Based upon Net Sales Target Achievements [Member] An amount, or portion of an amount, that is, will be, or may be based upon "net sales target achievements." acrx_PotentialMilestonePaymentsRelatedToNetSalesTarget Potential Milestone Payments Related To Net Sales Target Represents the potential milestone payments related to net sales target. acrx_PaymentsInExchangeForServicesUnderCollaborationAgreement Payments In Exchange For Services Under Collaboration Agreement The amount of payments to exchange development services. acrx_AmountOfBindingProductForecastRevenue Amount Of Binding Product Forecast Revenue The binding product forecast received under collaboration agreement. Prepaid expenses and other current assets invest_InvestmentWarrantsExercisePrice Investment Warrants, Exercise Price Expected dividend yield us-gaap_DisclosureTextBlockAbstract Notes to Financial Statements Exercise Price (in dollars per share) acrx_MilestonePaymentsReceived Milestone Payments Received Represents a milestone payment, or milestone payments, that were received by the Company during the period. us-gaap_FairValueAssumptionsRiskFreeInterestRate Risk-free interest rate acrx_RevenueRecognitionMilestoneMethodAgreedAdditionalAmount Revenue Recognition Milestone Method Agreed, Additional Amount Represents the agreed additional amount of revenue recognition for the milestone method. Zalviso [Member] Represents the product, Zalviso Expected life (in years) (Year) us-gaap_LiabilitiesCurrent Total current liabilities Based upon Successful Regulatory and Product Development Efforts [Member] An amount, or portion of an amount, that is, will be, or may be based upon "successful regulatory and product development efforts." acrx_RevenueRecognitionMilestoneMethodAgreedAdditionalAmountBasedOnEffortsAndTargets Revenue Recognition Milestone Method Agreed, Additional Amount, Based On Efforts And Targets The amount of additional milestone payments the Company is eligible to receive based upon successful regulatory and product development efforts and net sales target achievements. acrx_ManufacturingAgreementPercentageThereafter Manufacturing Agreement, Percentage, Thereafter Represents the manufacturing agreement percentage after the first five years. Raw materials acrx_ManufacturingAgreementPercentageForFiveYears Manufacturing Agreement, Percentage For Five Years Represents the percentage for five years for the manufacturing agreement. us-gaap_NonoperatingIncomeExpense Total other expense Finished goods Work-in-process acrx_CollaborationAgreementConsiderationAmount Collaboration Agreement Consideration, Amount Amount of aggregate consideration under collaboration agreement. us-gaap_OperatingExpenses Total operating costs and expenses Research and Development and Committee Participation Services [Member] Information about research and development and committee participation services. us-gaap_OtherExpenses Other Expenses Previously Delivered License [Member] Information about previously delivered license. General and administrative acrx_DiscountOnManufacturingServices Discount On Manufacturing Services Consideration allocated to significant and incremental discount on manufacturing services. acrx_CommitteeParticipationSercicesRecognized Committee Participation Sercices Recognized Consideration allocated to committee participation services. Interest income and other income (expense), net us-gaap_OtherNoncashIncomeExpense Other acrx_ManufacturingServicesRevenuesRelatedToBindingForecast Manufacturing Services Revenues Related To Binding Forecast Information about the revenue related to manufacturing services for the binding forecast of Products. us-gaap_OperatingIncomeLoss Loss from operations Deferred revenue, current portion Deferred Revenue, Current Schedule of Inventory, Current [Table Text Block] Inventory Disclosure [Text Block] Amendment Flag Long-term debt, current portion us-gaap_LongTermDebtCurrent Common stock, $0.001 par value—100,000,000 shares authorized as of March 31, 2017 and December 31, 2016; 45,371,351 and 45,333,790 shares issued and outstanding as of March 31, 2017 and December 31, 2016 us-gaap_FairValueAdjustmentOfWarrants Adjustments for change in fair value of warrant liability us-gaap_ProceedsFromSaleAndMaturityOfMarketableSecurities Proceeds from maturities of investments Common stock, authorized (in shares) Common stock, issued (in shares) us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number Fair Value Measurements, Recurring and Nonrecurring [Table Text Block] Common stock, par value (in dollars per share) us-gaap_ShareBasedCompensation Stock-based compensation Current Fiscal Year End Date Document Fiscal Period Focus us-gaap_AmortizationOfDebtDiscountPremium Amortization of Debt Discount (Premium) Document Fiscal Year Focus Document Period End Date Revenue Recognition Amended Agreements [Table Text Block] Tabular disclosure of the recognition of revenue under the amended agreements. us-gaap_RevenueRecognitionMilestoneMethodRevenueRecognized Revenue Recognition, Milestone Method, Revenue Recognized Revenue Recognized The amount of revenue recognized as a result of the revenue allocation under collaboration agreement. Warrants Disclosure [Text Block] The disclosure of warrants. Document Type Liability Related To Sale Of Future Royalties Disclosure [Text Block] The entire disclosure for liability related to sale of future royalties. Hercules Loan and Security Agreement [Member] Represents information pertaining to the Hercules loan and security agreement. us-gaap_DepreciationDepletionAndAmortization Depreciation and amortization acrx_NumberOfTranchesForLoanAndSecurityAgreement Number of Tranches for Loan and Security Agreement Represents the number of tranches for loan and security agreement. First Tranche [Member] Represents the first tranche. Accounts payable Document Information [Line Items] Collaborative Arrangement [Member] Document Information [Table] Second Tranche [Member] Represents the second tranche. us-gaap_AssetsCurrent Total current assets Accrued liabilities Long-term Debt, Type [Axis] Type of Arrangement and Non-arrangement Transactions [Axis] Entity Filer Category acrx_WarrantExercisableTerm Warrant Exercisable Term The warrants term. Entity Current Reporting Status Counterparty Name [Domain] Entity Voluntary Filers Long-term Debt, Type [Domain] Hercules Warrants [Member] Represents the Hercules Warrants. Arrangements and Non-arrangement Transactions [Domain] Cash, Cash Equivalents and Investments [Table Text Block] Counterparty Name [Axis] Entity Well-known Seasoned Issuer Amended and Restated Loan and Security Agreement [Member] Represents the amended and restated loan and security agreement. Third Tranche [Member] Represents the third tranche. acrx_CommonStockWarrantsExercised Common Stock Warrants Exercised Represents common stock warrants exercised. Employee Stock Purchase Plan (ESPP) [Member] Information about the employee stock purchase plan. acrx_PrepaymentChargeOfTermLoanPercentage Prepayment Charge Of Term Loan Percentage Represents the prepayment charge of the term loan as a percentage. Dilutive effect of warrants (in shares) acrx_AdditionalDefaultInterestRate Additional Default Interest Rate The addition percentage of interest in the event of default. Entity Central Index Key Entity Registrant Name Entity [Domain] Total assets measured at fair value Legal Entity [Axis] Class of Warrant or Right [Domain] us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number us-gaap_ClassOfWarrantOrRightOutstanding Class of Warrant or Right, Outstanding Class of Warrant or Right [Axis] us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1 Class of Warrant or Right, Exercise Price of Warrants or Rights Warrant liability acrx_PercentageOfRoyaltiesAndRightsUnderAgreement Percentage Of Royalties And Rights Under Agreement Percentage of royalties or milestone rights to be received under the agreement. Other Liabilities [Table Text Block] Current Liabilities: First Four Commercial Milestones [Member] Represents the detail of parts of royalties and rights received. PDL [Member] Information of related party. Entity Common Stock, Shares Outstanding (in shares) AcelRX [Member] The name or description of the company. us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant acrx_CommercialMilestonesValueMaximumAmountAvailable Commercial Milestones Value Maximum Amount Available The maximum value of commercial milestone payments available to the company. Additional paid-in capital us-gaap_NetIncomeLossAvailableToCommonStockholdersDiluted Diluted Remaining Commercial and All Development Milestone[Member] Detail of percentage the remaining commercial milestones and all remaining development milestones. Royalties [Member] The name or description of the arrangement. us-gaap_Assets Total Assets MAA Aproval [Member] The type or description of the arrangement. acrx_CommercialMilestonesValue Commercial Milestones Value The value of commercial milestone payments. Liability related to sale of future royalties as of March 31, 2017 Balance, liability related to sale of future royalties Total liability related to sale of future royalties current and non-current. Inventories Total Stockholders’ Deficit: Trading Symbol us-gaap_PaymentsToAcquirePropertyPlantAndEquipment Purchase of property and equipment Series Warrants [Member] Represents the reporting entity's series warrants. Basis of Presentation and Significant Accounting Policies [Text Block] Basic Net loss Net loss acrx_FairValueOfWarrantOnDateOfIssuance Fair Value Of Warrant On Date Of Issuance Represents the fair market value of the warrant on the date that was issued. us-gaap_StockholdersEquity Total stockholders’ deficit Plan Name [Axis] Plan Name [Domain] Other assets Commitments and Contingencies us-gaap_Liabilities Total liabilities acrx_WarrantsVestingConditionDescription Warrants Vesting Condition Description Represents the condition for vesting warrants. acrx_EstimatedFairValueOfWarrant Estimated Fair Value of Warrant Represents the estimated fair market value of warrants. acrx_FairValueOfWarrantUponExecutionOfSecuritiesPurchaseAgreement Fair Value of Warrant Upon Execution of Securities Purchase Agreement Represents the fair value of warrants upon the execution of the securities purchase agreement. Restricted Stock Units (RSUs) [Member] Cost of goods sold 2011 Equity Incentive Plan [Member] The name or description of the plan. 2012 Private Placement [Member] Information pertaining to the 2012 private placement offering. Warrant [Member] Changes in operating assets and liabilities: Antidilutive Securities, Name [Domain] Employee Stock Option [Member] Convertible Debt Securities [Member] Schedule of Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Table Text Block] Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table Text Block] Antidilutive Securities [Axis] Accounts receivable, net Statement [Line Items] Research and development Disclosure of Compensation Related Costs, Share-based Payments [Text Block] us-gaap_OtherComprehensiveIncomeLossTransfersFromHeldToMaturityToAvailableForSaleSecuritiesNetOfTax Other Comprehensive Income (Loss), Transfers from Held-to-maturity to Available-for-Sale Securities, Net of Tax Non-cash royalty revenue related to Royalty Monetization (See Note 8) Non-cash royalty revenue The amount of non-cash royalty revenue recognized in connection to royalty monetization. us-gaap_InterestExpense Interest Expense Interest expense Operating costs and expenses: Unrealized (losses) gains on available-for-sale securities Collaborative Arrangement Disclosure [Text Block] Investments [Domain] Investment Type [Axis] Current Assets: Property and equipment, net Non-cash interest expense related to debt financing Debt Instrument [Axis] Debt Instrument, Name [Domain] us-gaap_DebtInstrumentInterestRateStatedPercentage Debt Instrument, Interest Rate, Stated Percentage us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease Net decrease in cash and cash equivalents us-gaap_TableTextBlock Notes Tables us-gaap_DebtInstrumentFairValue Debt Instrument, Fair Value Disclosure us-gaap_DebtInstrumentFaceAmount Debt Instrument, Face Amount Grunenthal [Member] The name or description of the counterparty. us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperations Net cash provided by financing activities us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperations Net cash (used in) provided by investing activities Earnings Per Share [Text Block] us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations Net cash used in operating activities