Talphera (TLPH) 10-Q 5 May 15 2015 Q1 Quarterly report Financial data

Document_And_Entity_Informatio

Document And Entity Information	3 Months Ended
	Mar. 31, 2015	Apr. 22, 2015
Document and Entity Information [Abstract]
Entity Registrant Name	ACELRX PHARMACEUTICALS INC
Document Type	10-Q
Current Fiscal Year End Date	-19
Entity Common Stock, Shares Outstanding		44,335,196
Amendment Flag	FALSE
Entity Central Index Key	1427925
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Accelerated Filer
Entity Well-known Seasoned Issuer	No
Document Period End Date	31-Mar-15
Document Fiscal Year Focus	2015
Document Fiscal Period Focus	Q1

Condensed_Balance_Sheets_Curre

Condensed Balance Sheets (Current Period Unaudited) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Current Assets:
Cash and cash equivalents	$49,144	$60,038	[1]
Short-term investments	15,294	15,312	[1]
Prepaid expenses and other current assets	979	948	[1]
Total current assets	65,417	76,298	[1]
Property and equipment, net	9,846	9,818	[1]
Restricted cash	250	250	[1]
Other assets	79	81	[1]
Total Assets	75,592	86,447	[1]
Current Liabilities:
Accounts payable	2,685	2,431	[1]
Accrued liabilities	2,778	3,654	[1]
Deferred revenue, current portion	606	787	[1]
Long-term debt, current portion	9,291	6,859	[1]
Total current liabilities	15,360	13,731	[1]
Deferred rent	516	529	[1]
Long-term debt, net of current portion	15,850	18,046	[1]
Deferred revenue	1,626	1,626	[1]
Contingent put option liability	307	282	[1]
Warrant liability	848	5,577	[1]
Total liabilities	34,507	39,791	[1]
Stockholders’ Equity:
Common stock, $0.001 par value—100,000,000 shares authorized as of March 31, 2015 and December 31, 2014; 44,334,977 and 43,712,363 shares issued and outstanding as of March 31, 2015 and December 31, 2014	44	43	[1]
Additional paid-in capital	229,873	225,423	[1]
Accumulated deficit	-188,832	-178,806	[1]
Accumulated other comprehensive income (loss)		-4	[1]
Total stockholders’ equity	41,085	46,656	[1]
Total Liabilities and Stockholders’ Equity	$75,592	$86,447	[1]
[1]	The condensed balance sheet as of December 31, 2014 has been derived from the audited financial statements as of that date included in the Company's Annual Report on Form 10-K for the year ended December 31, 2014.

Condensed_Balance_Sheets_Curre1

Condensed Balance Sheets (Current Period Unaudited) (Parentheticals) (USD $)	Mar. 31, 2015	Dec. 31, 2014
Common stock, par value (in Dollars per share)	$0.00	$0.00	[1]
Common stock, shares authorized	100,000,000	100,000,000	[1]
Common stock, shares issued	44,334,977	43,712,363	[1]
Common stock, shares outstanding	44,334,977	43,712,363	[1]
[1]	The condensed balance sheet as of December 31, 2014 has been derived from the audited financial statements as of that date included in the Company's Annual Report on Form 10-K for the year ended December 31, 2014.

Condensed_Statements_of_Compre

Condensed Statements of Comprehensive Loss (Unaudited) (USD $)	3 Months Ended
In Thousands, except Share data, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Collaboration agreement revenue	$181	$95
Operating expenses:
Research and development	6,306	4,711
General and administrative	4,521	3,925
Restructuring costs	754
Total operating expenses	11,581	8,636
Loss from operations	-11,400	-8,541
Interest expense	-806	-472
Interest income and other income (expense), net	2,180	-618
Net loss	-10,026	-9,631
Other comprehensive loss:
Unrealized gains (losses) on available-for-sale securities	4
Comprehensive loss	($10,022)	($9,631)
Net loss per share of common stock, basic (in Dollars per share)	($0.23)	($0.22)
Net loss per share of common stock, diluted (in Dollars per share)	($0.27)	($0.22)
Shares used in computing net loss per share of common stock, basic (in Shares)	43,873,108	43,190,409
Shares used in computing net loss per share of common stock, diluted – see Note 8 (in Shares)	44,426,457	43,190,409

Condensed_Statements_of_Cash_F

Condensed Statements of Cash Flows (Unaudited) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015		Mar. 31, 2014
Cash flows from operating activities:
Net loss	($10,026)		($9,631)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	488		162
Amortization of premium/discount on investments, net	20		72
Interest expense related to debt financing	238		131
Restructuring costs	-754
Stock-based compensation	1,538		975
Revaluation of put option and PIPE warrant liabilities	-2,160		646
Changes in operating assets and liabilities:
Prepaid expenses and other assets	-31		-195
Accounts payable	254		-156
Accrued liabilities	-122		-2,012
Deferred revenue	-181		-95
Deferred rent	-13		-29
Net cash used in operating activities	-10,749		-10,132
Cash flows from investing activities:
Purchase of property and equipment	-516		-1,143
Purchase of investments	-2,468		-1,359
Proceeds from maturity of investments	2,470		1,260
Net cash used in investing activities	-514		-1,242
Cash flows from financing activities:
Net proceeds from issuance of common stock through equity plans and exercise of warrants	369		560
Net cash provided by financing activities	369		560
Net decrease in cash and cash equivalents	-10,894		-10,814
Cash and cash equivalents—Beginning of period	60,038	[1]	88,401
Cash and cash equivalents—End of period	49,144		77,587
Issuance of common stock upon cashless exercise of warrants	2,544
Purchases of property and equipment in Accounts payable	338
Purchases of property and equipment in Accrued liabilities			$420
[1]	The condensed balance sheet as of December 31, 2014 has been derived from the audited financial statements as of that date included in the Company's Annual Report on Form 10-K for the year ended December 31, 2014.

Note_1_Organization_and_Summar

Note 1 - Organization and Summary of Significant Accounting Policies	3 Months Ended
	Mar. 31, 2015
Disclosure Text Block [Abstract]
Basis of Presentation and Significant Accounting Policies [Text Block]	1. Organization and Summary of Significant Accounting Policies
	The Company
	AcelRx Pharmaceuticals, Inc., or the Company or AcelRx, was incorporated in Delaware on July 13, 2005 as SuRx, Inc., and in January 2006, the Company changed its name to AcelRx Pharmaceuticals, Inc. The Company’s operations are based in Redwood City, California.
	AcelRx is a specialty pharmaceutical company focused on the development and commercialization of innovative therapies for the treatment of acute pain. AcelRx intends to commercialize its product candidates in the United States and license the development and commercialization rights to its product candidates for sale outside of the United States through strategic partnerships and collaborations. On July 25, 2014, the U.S. Food and Drug Administration, or FDA, issued a Complete Response Letter, or CRL, for the Company’s new drug application, or NDA, for Zalviso™ (sufentanil sublingual tablet system). In March 2015, the Company received a request from the FDA stating that in addition to the bench testing and two Human Factors studies it has performed in response to the CRL, a clinical trial is needed to assess the risk of inadvertent dispensing and overall risk of dispensing failures. On April 21, 2015, the Company submitted a request to the Division of Anesthesia, Analgesia, and Addiction Products, or the Division, of the FDA for a Type B meeting. On May 1, 2015, the Division notified the Company that the request for a meeting was denied and restated the Division’s view that a clinical study is required. The Company is consulting with regulatory, legal and clinical advisors to determine its next steps. The Company will be considering all options to determine a pathway forward for Zalviso, including the possibility of dispute resolution through one of the FDA prescribed pathways, as well as conducting additional clinical and Human Factors studies. The proposed indication for Zalviso is for the management of moderate-to-severe acute pain in adult patients in the hospital setting. Zalviso consists of sufentanil sublingual tablets delivered by the Zalviso System, a needle-free, handheld, patient-administered, pain management system (together, “Zalviso”).
	The Company has incurred recurring operating losses and negative cash flows from operating activities since inception and expects to continue to incur negative cash flows until its product candidates are approved for marketing in the United States and other countries, in which it has and intends to license its products, which may never occur. In previous years, prior to the commercial collaboration of Zalviso in Europe, AcelRx was considered a development stage company.
	The Company has one business activity, which is the development and commercialization of product candidates for the treatment of pain, and a single reporting and operating unit structure.
	Basis of Presentation
	The accompanying unaudited condensed financial statements have been prepared in accordance with accounting principles generally accepted in the United States for interim financial information and the rules and regulations of the U.S. Securities and Exchange Commission, or SEC. Accordingly, they do not include all of the information and footnotes required by accounting principles generally accepted in the United States for complete financial statements. In the opinion of management, all adjustments (consisting of normal recurring adjustments) considered necessary for a fair presentation have been included.
	Operating results for the three months ended March 31, 2015, are not necessarily indicative of the results that may be expected for the year ending December 31, 2015. The condensed balance sheet as of December 31, 2014, was derived from the Company’s audited financial statements as of December 31, 2014, included in the Company’s Annual Report on Form 10-K filed with the SEC. These financial statements should be read in conjunction with the Company’s Annual Report on Form 10-K for the year ended December 31, 2014, which includes a broader discussion of the Company’s business and the risks inherent therein.
	Use of Estimates
	The preparation of financial statements in conformity with accounting principles generally accepted in the United States requires management to make estimates and assumptions that affect the amounts reported in the condensed financial statements and accompanying notes. Management evaluates its estimates on an ongoing basis including critical accounting policies. Estimates are based on historical experience and on various other market-specific and other relevant assumptions that the Company believes to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities that are not readily apparent from other sources. Actual results could differ from those estimates.
	Recently Issued Accounting Standards
	There have been no recent accounting pronouncements or changes in accounting pronouncements during the three months ended March 31, 2015, as compared to the recent accounting pronouncements described in the Company’s Form 10-K for the year ended December 31, 2014, that are of significance, or potential significance to the Company.

Note_2_Investments_and_Fair_Va

Note 2 - Investments and Fair Value Measurement	3 Months Ended
	Mar. 31, 2015
Investments And Fair Value Measurement Disclosure [Abstract]
Investments And Fair Value Measurement Disclosure [Text Block]	2. Investments and Fair Value Measurement
	Investments
	The Company classifies its marketable securities as available-for-sale and records its investments at fair value. Available-for-sale securities are carried at estimated fair value based on quoted market prices or observable market inputs of almost identical assets, with the unrealized holding gains and losses included in accumulated other comprehensive income. Marketable securities which have maturities beyond one year as of the end of the reporting period are classified as non-current.
	The table below summarizes the Company’s cash, cash equivalents and investments (in thousands):
		As of March 31, 2015
		Amortized Cost				Gross Unrealized		Gross Unrealized			Fair
						Gains		Losses			Value
	Cash and cash equivalents:
	Cash	$	49,097			$	—	$	—		$	49,097
	Money market funds		47				—		—			47
	Total cash and cash equivalents		49,144				—		—			49,144
	Marketable securities:
	U.S. government agency securities		15,293				1		—		$	15,294
	Total marketable securities		15,293				1		—		$	15,294
	Total cash, cash equivalents and investments	$	64,437			$	1	$	—		$	64,438
		As of December 31, 2014
		Amortized Cost				Gross Unrealized		Gross Unrealized			Fair
						Gains		Losses			Value
	Cash and cash equivalents:
	Cash	$	60,005			$	—	$	—		$	60,005
	Money market funds		33				—		—			33
	Total cash and cash equivalents		60,038				—		—		$	60,038
	Marketable securities:
	U.S. government agency securities		15,316				—		(4	)		15,312
	Total marketable securities		15,316				—		(4	)	$	15,312
	Total cash, cash equivalents and investments	$	75,354			$	—	$	(4	)	$	73,350
	As of March 31, 2015 and December 31, 2014, none of the available-for-sale securities held by the Company had material unrealized losses. There were no other-than-temporary impairments for these securities at March 31, 2015 or December 31, 2014. No gross realized gains or losses were recognized on the available-for-sale securities and, accordingly, there were no amounts reclassified out of accumulated other comprehensive income to earnings during the three months ended March 31, 2015 and 2014.
	As of March 31, 2015 and December 31, 2014, the contractual maturity of all investments held was less than one year.
	Fair Value Measurement
	The Company’s financial instruments consist of Level I and Level II assets and Level III liabilities. Level I securities include highly liquid money market funds and are valued based on quoted market prices. For Level II instruments, the Company estimates fair value by utilizing third party pricing services in developing fair value measurements where fair value is based on valuation methodologies such as models using observable market inputs, including benchmark yields, reported trades, broker/dealer quotes, bids, offers and other reference data. Such Level II instruments typically include U.S. treasury and U.S. government agency obligations. As of March 31, 2015 and December 31, 2014, the Company held, in addition to Level I and Level II assets, a contingent put option liability associated with the Company’s Amended and Restated Loan and Security Agreement, or the Amended Loan Agreement, with Hercules Technology II, L.P. and Hercules Technology Growth Capital, Inc., collectively referred to as Hercules, which amends and restates the loan and security agreement with Hercules dated as of June 29, 2011, or the Original Loan Agreement, and which was classified as a Level III liability. See Note 4 “Long-Term Debt,” for further description. The Company’s estimate of fair value of the contingent put option liability was determined by using a risk-neutral valuation model, wherein the fair value of the underlying debt facility is estimated both with and without the presence of the default provisions, holding all other assumptions constant. The resulting difference between the two estimated fair values is the estimated fair value of the default provisions, or the contingent put option. Changes to the estimated fair value of these liabilities are recorded in interest income and other income (expense), net in the condensed statements of comprehensive loss. The fair value of the underlying debt facility is estimated by calculating the expected cash flows in consideration of an estimated probability of default and expected recovery rate in default, and discounting such cash flows back to the reporting date using a risk-free rate. As of March 31, 2015 and December 31, 2014, the Company also held a Level III liability associated with warrants, or PIPE warrants, issued in connection with the Company’s private placement equity offering, completed in June 2012. The PIPE warrants are considered a liability and are valued using the Black-Scholes option-pricing model, the inputs for which include exercise price of the PIPE warrants, market price of the underlying common shares, expected term, volatility based on a group of the Company’s peers and the risk-free rate corresponding to the expected term of the PIPE warrants. Changes to any of the inputs can have a significant impact to the estimated fair value of the PIPE warrants.
	The following table sets forth the fair value of the Company’s financial assets and liabilities by level within the fair value hierarchy (in thousands):
		As of March 31, 2015
		Fair Value				Level I		Level II			Level III
	Assets
	Money market funds	$	47			$	47	$	—		$	—
	U.S. government agency obligations		15,294				—		15,294			—
	Total assets measured at fair value	$	15,341			$	47	$	15,294		$	—
	Liabilities
	PIPE warrants	$	848				—		—		$	848
	Contingent put option liability		307				—		—			307
	Total liabilities measured at fair value	$	1,155			$	—	$	—		$	1,155
		As of December 31, 2014
		Fair Value				Level I		Level II			Level III
	Assets
	Money market funds	$	33			$	33	$	—		$	—
	U.S. government agency obligations		15,312				—		15,312			—
	Total assets measured at fair value	$	15,345			$	33	$	15,312		$	—
	Liabilities
	PIPE warrants	$	5,577				—		—		$	5,577
	Contingent put option liability	$	282				—		—		$	282
	Total liabilities measured at fair value	$	5,859			$	—	$	—		$	5,859
	The following table sets forth the assumptions used in the Black-Scholes option-pricing model to estimate the fair value of the PIPE warrants as of March 31, 2015:
	Market price	$	3.86
	Exercise price	$	3.4
	Risk-free interest rate		0.89	%
	Expected volatility		61	%
	Expected life (in years)		2.7
	Expected dividend yield		0	%
	The following table sets forth the assumptions used in the Black-Scholes option-pricing model to estimate the fair value of the PIPE warrants as of December 31, 2014:
	Market price	$	6.73
	Exercise price	$	3.4
	Risk-free interest rate		1.1	%
	Expected volatility		61	%
	Expected life (in years)		2.92
Expected dividend yield		0	%
The following tables set forth a summary of the changes in the fair value of the Company’s Level III financial liabilities for the three months ended March 31, 2015 and March 31, 2014 (in thousands):
			Three Months
			Ended
			March 31,
			2015
Fair value—beginning of period		$	5,859
Change in fair value of PIPE warrants			(4,729	)
Change in fair value of contingent put option associated with Amended Loan Agreement with Hercules			25
Fair value—end of period		$	1,155
	Three Months
	Ended
	March 31,
	2014
Fair value—beginning of period	$	13,445
Change in fair value of PIPE warrants		684
Change in fair value of contingent put option associated with Original Loan Agreement with Hercules		(38	)
Fair value—end of period	$	14,091

Note_3_Collaboration_Agreement

Note 3 - Collaboration Agreement	3 Months Ended
	Mar. 31, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Collaborative Arrangement Disclosure [Text Block]	3. Collaboration Agreement
	On December 16, 2013, AcelRx and Grünenthal GmbH, or Grünenthal, entered into a Collaboration and License Agreement, or the License Agreement, and related Manufacture and Supply Agreement, or the Manufacturing Agreement, and together with the License Agreement, or the Agreements. The License Agreement grants Grünenthal rights to commercialize Zalviso, the Company’s novel sublingual patient-controlled analgesia, or PCA, system, or the Product, in the countries of the European Union, Switzerland, Liechtenstein, Iceland, Norway and Australia, or the Territory, for human use in pain treatment within or dispensed by hospitals, hospices, nursing homes and other medically-supervised settings, or the Field. The Company retains rights with respect to the Product in countries outside the Territory, including the United States, Asia and Latin America. Under the Supply Agreement, the Company will exclusively manufacture and supply the Product to Grünenthal for the Field in the Territory.
	License Agreement
	Under the terms of the License Agreement, Grünenthal has the exclusive right to commercialize the Product in the Field in the Territory. The Company retains control of clinical development, while Grünenthal and the Company will be responsible for certain development activities pursuant to a development plan as agreed between the parties. The Company will not receive separate payment for such development activities. Grünenthal is exclusively responsible for marketing approval applications and other regulatory filings relating to the sufentanil sublingual tablet drug cartridge for the Product in the Field in the Territory, while the Company is responsible for the CE Mark and other regulatory filings relating to device portions of the Product. A CE Mark (#611742) for Zalviso was obtained in the fourth quarter 2014 which specifies AcelRx as the device design authority and manufacturer.
	The Company received an upfront non-refundable cash payment of $30.0 million in December 2013, and a milestone payment of $5.0 million related to the MAA submission in the third quarter of 2014. The Company is eligible to receive an additional $15.0 million milestone payment upon the approval of the MAA. If the MAA is approved, the Company is eligible to receive approximately $200.0 million in additional milestone payments, based upon successful regulatory and product development efforts ($28.5 million) and net sales target achievements ($171.5 million). Grünenthal will also make tiered royalty and supply and trademark fee payments in the mid-teens up to the mid-twenties percent range on net sales of Zalviso.
	Unless earlier terminated, the License Agreement continues in effect until the expiration of the obligation of Grünenthal to make royalty and supply and trademark fee payments, which supply and trademark fee continues for so long as the Company continues to supply the Product to Grünenthal. The License Agreement is subject to earlier termination in the event the parties mutually agree, by a party in the event of an uncured material breach by the other party, upon the bankruptcy or insolvency of either party, or by Grünenthal for convenience.
	Manufacturing Agreement
	Under the terms of the Manufacturing Agreement, the Company will manufacture and supply the Product for use in the Field for the Territory exclusively for Grünenthal. Grünenthal shall purchase from AcelRx, during the first five years after the effective date of the Manufacturing Agreement, 100% and thereafter 80% of Grünenthal’s and its sublicensees’ and distributors’ requirements of Product for use in the Field for the Territory. The Product will be supplied at the Company’s fully burdened manufacturing cost (as defined in the Manufacturing Agreement). The Manufacturing Agreement requires the Company to use commercially reasonable efforts to enter stand-by contracts with third parties providing significant supply and manufacturing services and under certain specified conditions permits Grünenthal to use a third party back-up manufacturer to manufacture the Product for Grünenthal’s commercial sale in the Territory.
	Unless earlier terminated, the Manufacturing Agreement continues in effect until the later of the expiration of the obligation of Grünenthal to make royalty and supply and trademark fee payments or the end of any transition period for manufacturing obligations due to the expiration or termination of the License Agreement. The Manufacturing Agreement is subject to earlier termination in connection with certain termination events in the License Agreement, in the event the parties mutually agree, by a party in the event of an uncured material breach by the other party or upon the bankruptcy or insolvency of either party.
	The Company identified the following four significant non-contingent performance deliverables under the agreements: 1) intellectual property (license), 2) the obligation to provide research and development services, 3) the significant and incremental discount on the manufacturing of Zalviso for commercial purposes, and 4) the obligation to participate on the joint steering committee.
	The Company considered the provisions of the multiple-element arrangement guidance in determining whether the deliverables outlined above have standalone value and thus should be treated as separate units of accounting. Company’s management determined that the license has standalone value and represents a separate unit of accounting because the rights conveyed permit Grünenthal to perform all efforts necessary to commercialize and begin selling the product upon regulatory approval. In addition, Grünenthal has the appropriate development, regulatory and commercial expertise with products similar to the product licensed under the agreement and has the ability to engage third parties to manufacture the product allowing Grünenthal to realize the value of the license without receiving any of the remaining deliverables. Grünenthal can also sublicense its license rights to third parties. Also, the Company’s management determined that the research services, committee participation and implied discount associated with the manufacturing services each represent individual units of accounting as Grünenthal could perform such services and/or could acquire these on a separate basis.
	The Company developed best estimates of selling prices for each deliverable in order to allocate the noncontingent arrangement consideration to the four units of accounting.
	The Company’s management determined the best estimate of selling price for the license based on Grünenthal’s estimated future cash flows arising from the arrangement. Embedded in the estimate were significant assumptions regarding regulatory expenses, revenue, including potential customer market for the product and product price, costs to manufacture the product and the discount rate. The Company’s management determined the best estimate of selling price of the research and development services and committee participation based on the nature and timing of the services to be performed and in consideration of personnel and other costs incurred in the delivery of the services. For the discount on manufacturing services, Company’s management estimated the selling price based on the market level of contract manufacturing margin it could have received if it were engaged to supply products to a customer in a separate transaction.
	The Agreements entitle the Company to receive additional payments upon the achievement of certain development and sales milestones. Based on ASC Topic 605-28, Revenue Recognition — Milestone Method, the Company evaluates contingent milestones at inception of the agreement, and recognizes consideration that is contingent upon the achievement of a milestone in its entirety as revenue in the period in which the milestone is achieved only if the milestone is considered substantive in its entirety. Milestones are events which have the following characteristics: (i) they can be achieved based in whole or in part on either the Company’s performance or on the occurrence of a specific outcome resulting from the Company’s performance, (ii) there was substantive uncertainty at the date the agreement was entered into that the event would be achieved and, (iii) they would result in additional payments due to the Company. A milestone is considered substantive if the following criteria are met: (i) the consideration is commensurate with either (1) the entity’s performance to achieve the milestone, or (2) the enhancement of the value of the delivered item (s) as a result of a specific outcome resulting from the entity’s performance to achieve the milestone, (ii) the consideration relates solely to past performance and, (iii) the consideration is reasonable relative to all of the other deliverables and payment terms, including other potential milestone consideration, within the arrangement.
	The substantive milestone payments will be recognized as revenue in their entirety upon the achievement of each substantive milestone. Based on the criteria noted above, the identified substantive milestones in the agreement pertain to post approval product enhancements, expanded market opportunities and manufacturing efficiencies for Zalviso. Each of these potential achievements is based primarily on the Company’s performance and involves substantive uncertainty as achievement of these milestones requires future research, development and regulatory activities, which are inherently uncertain in nature. The Company determined that the consideration for each milestone was commensurate with the Company’s performance to achieve the milestone, including future research, development, manufacturing and regulatory activities and that the consideration is reasonable relative to all of the other deliverables and payments within the arrangement. Aggregate potential payments for these milestones total $28.5 million.
	In addition to substantive milestones, two milestones associated with the Agreements were deemed not to be substantive. These milestones pertain to regulatory developments for Zalviso in Europe, which Company’s management deemed to be not substantive due to the level of performance associated with future achievement of these milestones. Aggregate potential payments for these milestones total $20.0 million. In July 2014, Grünenthal submitted a Marketing Authorization Application, or MAA, to the European Medicines Agency, or EMA, for Zalviso for the management of moderate-to-severe acute pain in adult patients in a medically supervised environment. Under the terms of the License Agreement with Grünenthal, the Company received a cash payment of $5.0 million for the MAA submission in the third quarter of 2014. The Company is eligible to receive an additional $15.0 million milestone payment upon the approval of the MAA.
	The Agreements also include milestone payments related to specified net sales targets, totaling $171.5 million. The sales-based milestones do not meet the definition of a milestone under ASU 2010-17 because the achievement of these milestones is solely dependent on counter-party performance and not on any performance obligations of the Company.
	The Company recognized $181,000 and $95,000 of previously deferred revenue related to research and development services under the collaboration agreement during the three months ended March 31, 2015 and March 31, 2014, respectively. As of March 31, 2015, the Company had a deferred revenue balance of $2.2 million. There were no milestone payments received or recognized under these Agreements during the three months ended March 31, 2015.

Note_4_Longterm_Debt

Note 4 - Long-term Debt	3 Months Ended
	Mar. 31, 2015
Disclosure Text Block [Abstract]
Long-term Debt [Text Block]	4. Long-Term Debt
	Hercules Loan and Security Agreements
	In June 2011, AcelRx entered into a loan and security agreement with Hercules, under which AcelRx borrowed $20.0 million in two tranches of $10.0 million each, represented by secured convertible term promissory notes. The Company’s obligations associated with the agreement are secured by a security interest in substantially all of its assets, other than its intellectual property.
	The Company borrowed the first tranche of $10.0 million upon the closing of the transaction on June 29, 2011 and borrowed the second tranche of $10.0 million in December 2011. The Company used a portion of the proceeds from the first tranche to repay the remaining obligations under that certain loan and security agreement between the Company and Pinnacle Ventures, L.L.C., or Pinnacle Ventures, dated September 16, 2008. The agreement with Pinnacle Ventures is described further below. The interest rate for each tranche was 8.50%. In connection with the loan, the Company issued Hercules seven-year warrants to purchase an aggregate of 274,508 shares of common stock at a price of $3.06 per share. See Note 5 “Warrants,” for further description.
	On December 16, 2013, AcelRx entered into an Amended and Restated Loan and Security Agreement, or the Loan Agreement with Hercules Technology II, L.P. and Hercules Technology Growth Capital, Inc., together, the Lenders, under which the Company may borrow up to $40.0 million in three tranches. The loans are represented by secured convertible term promissory notes, collectively, the Notes. The Loan Agreement amends and restates the Loan and Security Agreement between the Company and the Lenders dated as of June 29, 2011, or the Original Loan Agreement, as noted above. The Company borrowed the first tranche of $15.0 million upon closing of the transaction on December 16, 2013, and the second tranche of $10.0 million on June 16, 2014. The Company used approximately $8.6 million of the proceeds from the first tranche to repay its obligations under the Original Loan Agreement. The Company recorded the new debt at an estimated fair value of $24.9 million as of December 31, 2014.
	On September 24, 2014, the Company entered into an amendment, or the Amendment, to the Loan Agreement with Hercules. The Amendment extends the time period under which the Company can draw down the third tranche, of up to $15.0 million, from March 15, 2015 to August 1, 2015, subject to the Company obtaining approval for Zalviso from the U.S. Food and Drug Administration. The Company does not believe it will receive FDA approval of Zalviso by August 1, 2015 and as such, will not have access to the third tranche under the Loan Agreement, as amended (the “Amended Loan Agreement”).
	The interest rate for each tranche will be calculated at a rate equal to the greater of either (i) 9.10% plus the prime rate as reported from time to time in The Wall Street Journal minus 5.25%, and (ii) 9.10%. Payments under the Amended Loan Agreement are interest only until April 1, 2015, followed by equal monthly payments of principal and interest through the scheduled maturity date on October 1, 2017, or the Loan Maturity Date. In addition, a final payment equal to $1.7 million will be due on the Loan Maturity Date, or such earlier date specified in the Amended Loan Agreement. The Company’s obligations under the Amended Loan Agreement are secured by a security interest in substantially all of its assets, other than its intellectual property.
	If the Company prepays the Amended Loan Agreement prior to maturity, it will pay Hercules a prepayment charge, based on a percentage of the then outstanding principal balance, 2% if the prepayment occurs after December 16, 2014, but prior to December 16, 2015, or 1% if the prepayment occurs after December 16, 2015.
	Subject to certain conditions and limitations set forth in the Amended Loan Agreement, the Company has the right to convert up to $5.0 million of scheduled principal installments under the Notes into freely tradeable shares of the Company’s common stock, or Common Stock. The number of shares of Common Stock that would be issued upon conversion of the Amended Notes would be equal to the number determined by dividing (x) the product of (A) the principal amount to be paid in shares of Common Stock and (B) 103%, by (y) $9.30 (subject to certain proportional adjustments as provided for in the Amended Loan Agreement).
	The Amended Loan Agreement includes customary affirmative and restrictive covenants, but does not include any financial maintenance covenants, and also includes standard events of default, including payment defaults, breaches of covenants following any applicable cure period, a material impairment in the perfection or priority of Hercules’ security interest or in the value of the collateral, and events relating to bankruptcy or insolvency. Upon the occurrence of an event of default, a default interest rate of an additional 5% may be applied to the outstanding loan balances, and Hercules may declare all outstanding obligations immediately due and payable and take such other actions as set forth in the Amended Loan Agreement.
	In connection with the Amended Loan Agreement, the Company issued a warrant to each Lender which, collectively, are exercisable for an aggregate of 176,730 shares of common stock and each carry an exercise price of $6.79 per share. See Note 5 “Warrants,” for further description.
	Upon an event of default, including a change of control, Hercules has the option to accelerate repayment of the Amended Loan Agreement, including payment of any applicable prepayment charges, which range from 1%-3% of the outstanding loan balance and accrued interest, as well as a final payment fee of $1.7 million. This option is considered a contingent put option liability, as the holder of the loan may exercise the option in the event of default, and is considered an embedded derivative, which must be valued and separately accounted for in the Company’s financial statements. As the amendment of the loan agreement was considered an extinguishment, the contingent put option liability associated with the Original Loan Agreement, which had an estimated fair value of $32,000 at the time of the amendment, was written off as a part of the loss on extinguishment, and a new contingent put option liability was established. As of March 31, 2015 and December 31, 2014, the estimated fair value of the contingent put option liability was $307,000 and $282,000, respectively, which was determined by using a risk-neutral valuation model, wherein the fair value of the underlying debt facility is estimated both with and without the presence of the default provisions, holding all other assumptions constant. The resulting difference between the two estimated fair values is the estimated fair value of the default provisions, or the contingent put option. The fair value of the underlying debt facility is estimated by calculating the expected cash flows in consideration of an estimated probability of default and expected recovery rate in default, and discounting such cash flows back to the reporting date using a risk-free rate. The contingent put option liability was recorded as a debt discount to the loan and consequently a reduction to the carrying value of the loan. The contingent put option liability is revalued at the end of each reporting period and any change in the fair value is recognized in interest income and other income (expense), net in the statements of comprehensive loss.
	As of March 31, 2015, the Company had outstanding borrowings under the Amended Loan Agreement of $25.1 million. Interest expense related to the Amended Loan Agreement was $0.8 million for the three months March 31, 2015.

Note_5_Warrants

Note 5 - Warrants	3 Months Ended
	Mar. 31, 2015
Warrants Disclosure [Abstract]
Warrants Disclosure [Text Block]	5. Warrants
	Series A Warrants
	As of March 31, 2015, warrants to purchase 3,425 shares of common stock had not been exercised and were still outstanding. These warrants expire in March 2017.
	Hercules Warrants
	In connection with the Amended Loan Agreement, executed in December 2013, the Company issued warrants to Hercules which are exercisable for an aggregate of 176,730 shares of common stock with an exercise price of $6.79 per share (the “Warrants”). Each Warrant may be exercised on a cashless basis. The Warrants are exercisable for a term beginning on the date of issuance and ending on the earlier to occur of five years from the date of issuance or the consummation of certain acquisitions of the Company as set forth in the Warrants. The number of shares for which the Warrants are exercisable and the associated exercise price are subject to certain proportional adjustments as set forth in the Warrants. The Company estimated the fair value of these warrants as of the issuance date to be $1.1 million, which was used in the estimating the fair value of the amended debt instrument and was recorded as equity. The fair value of the warrants was calculated using the Black-Scholes option-valuation model, and was based on the strike price of $6.79, the stock price at issuance of $9.67, the five-year contractual term of the warrants, a risk-free interest rate of 1.55%, expected volatility of 71% and 0% expected dividend yield.
	As of March 31, 2015, warrants to purchase 176,730 shares of common stock issued to Hercules had not been exercised and were still outstanding. These warrants expire in December 2018.
	In connection with the original loan and security agreement with Hercules, executed in June 2011, the Company issued to Hercules warrants to purchase an aggregate of 274,508 shares of common stock at a price of $3.06 per share, which were net exercised for 183,404 shares of common stock during the year ended December 31, 2013.
	2012 Private Placement Warrants
	In connection with the Private Placement, completed in June 2012, the Company issued PIPE warrants to purchase up to 2,630,103 shares of common stock. The per share exercise price of the PIPE warrants was $3.40 which equals the closing consolidated bid price of the Company’s common stock on May 29, 2012, the effective date of the Purchase Agreement. The PIPE warrants issued in the Private Placement became exercisable six months after the issuance date, and expire on the five year anniversary of the initial exercisability date. Under the terms of the PIPE warrants, upon certain transactions, including a merger, tender offer, sale of all or substantially all of the assets of the Company or if a person or group shall become the owner of 50% of the Company’s issued and outstanding common stock, which is outside of the Company’s control, each PIPE warrant holder may elect to receive a cash payment in exchange for the warrant, in an amount determined by application of the Black-Scholes option-pricing model. Accordingly, the PIPE warrants were recorded as a liability at fair value, as determined by the Black-Scholes option-pricing model, and then marked to fair value each reporting period, with changes in estimated fair value recorded through the Statements of Comprehensive Loss in interest income and other income (expense), net. The Black-Scholes assumptions used to value the PIPE warrants are disclosed in Note 2 “Investments and Fair Value Measurement.”
	Upon execution of the Purchase Agreement, the fair value of the PIPE warrants was estimated to be $5.8 million, which was recorded as a liability. As of March 31, 2015, the fair value of the PIPE warrants was estimated to be $0.8 million. The change in fair value for the three months ended March 31, 2015, which was recorded as other income, was $2.2 million.
	During the three months ended March 31, 2015, PIPE warrants to purchase 847,058 shares were net exercised for 527,101 shares of common stock. As of March 31, 2015, PIPE warrants to purchase 512,456 shares of common stock issued in connection with the Private Placement had not been exercised and were outstanding. These warrants expire in November 2017.

Note_6_Stockbased_Compensation

Note 6 - Stock-based Compensation	3 Months Ended
	Mar. 31, 2015
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Disclosure of Compensation Related Costs, Share-based Payments [Text Block]	6. Stock-Based Compensation
	The Company recorded total stock-based compensation expense for stock options, stock awards and the 2011 Employee Stock Purchase Plan as follows (in thousands):
		Three Months Ended
		March 31,
		2015		2014
	Expenses:
	Research and development	$	702	$	479
	General and administrative		836		496
	Total stock-based compensation expense	$	1,538	$	975
	As of March 31, 2015 there were 2,603,962 shares available for grant, 5,582,360 options outstanding and no restricted stock units outstanding under the Company’s 2011 Equity Incentive Plan.

Note_7_Restructuring_Costs

Note 7 - Restructuring Costs	3 Months Ended
	Mar. 31, 2015
Restructuring and Related Activities [Abstract]
Restructuring and Related Activities Disclosure [Text Block]	7. Restructuring Costs
	On March 19, 2015, the Board of Directors of the Company, in connection with its efforts to reduce operating costs, conserve capital, focus the Company's financial and development resources on working with the FDA to seek marketing approval for Zalviso, and continuing development of ARX-04, implemented a cost reduction plan. The cost reduction plan reduced the Company’s workforce by 19 employees, approximately 36% of total headcount, in the first quarter of 2015. In the three months ended March 31, 2015, the Company accrued $754,000 in employee termination benefits related to this restructuring, which was charged to restructuring costs in the Statements of Comprehensive Loss. The balance of the restructuring liability at March 31, 2015 was $754,000. No additional charges are anticipated in connection with this cost reduction plan. The majority of this restructuring liability will be paid in the second quarter of 2015. The Company anticipates the restructuring liability will be fully disbursed by December 31, 2015.

Note_8_Net_Loss_Per_Share_of_C

Note 8 - Net Loss Per Share of Common Stock	3 Months Ended
	Mar. 31, 2015
Earnings Per Share [Abstract]
Earnings Per Share [Text Block]	8. Net Loss per Share of Common Stock
	The Company’s basic net loss per share of common stock is calculated by dividing the net loss by the weighted average number of shares of common stock outstanding for the period. The diluted net loss per share of common stock is computed by giving effect to all potential common stock equivalents outstanding for the period determined using the treasury stock method. For purposes of this calculation, options to purchase common stock and warrants to purchase common stock were considered to be common stock equivalents. In periods with a reported net loss, common stock equivalents are excluded from the calculation of diluted net loss per share of common stock if their effect is antidilutive.
	During the three months ended March 31, 2015, the PIPE warrants had a dilutive impact to net loss per share due to a lower share price at March 31, 2015, compared to the closing share price on December 31, 2014. The decrease in share price created a lower Black-Scholes value and lower liability for the PIPE warrants, which resulted in other income during the three months ended March 31, 2015. The calculation of diluted net loss per share requires that, to the extent the average market price of the underlying shares for the reporting period exceeds the exercise price of the PIPE warrants and the presumed exercise of such securities are dilutive to loss per share for the period, adjustments to net loss used in the calculation are required to remove the change in fair value of the PIPE warrants for the period. Likewise, adjustments to the denominator are required to reflect the related dilutive shares.
	The following table sets forth the computation of the Company’s basic and diluted net loss per share of common stock during the three months ended March 31, 2015 and 2014 (in thousands, except for share and per share amounts):
		Three Months Ended
		March 31,
		2015			2014
	Numerator
	Net loss used to compute net loss per share:
	Basic	$	(10,026	)	$	(9,631	)
	Adjustments for change in fair value of warrant liability		(2,186	)		—
	Diluted	$	(12,212	)	$	(9,631	)
	Denominator
	Weighted average shares outstanding used to compute net loss per share:
	Basic		43,873,108			43,190,409
	Dilutive effect of warrants		553,349			—
	Diluted		44,426,457			43,190,409
	Net loss per share — basic	$	(0.23	)	$	(0.22	)
	Net loss per share — diluted	$	(0.27	)	$	(0.22	)
	The following outstanding shares of common stock equivalents were excluded from the computation of diluted net loss per share of common stock for the periods presented because including them would have been antidilutive:
		March 31,
		2015			2014
	Stock options to purchase common stock		5,582,360			5,083,428
	Restricted stock units		—			—
	Common stock warrants		692,611			1,674,669

Note_9_Manufacturing_Agreement

Note 9 - Manufacturing Agreements	3 Months Ended
	Mar. 31, 2015
Manufacturing Agreement [Abstract]
Manufacturing Agreement [Text Block]	9. Manufacturing Agreements
	Patheon
	In January 2013, the Company and Patheon Pharmaceuticals Inc., or Patheon, entered into a Manufacturing Services Agreement, or the Services Agreement, and a related Amended and Restated Capital Expenditure and Equipment Agreement, or the Capital Agreement, relating to the manufacture of sufentanil tablets, or the Product, for use with the Company’s Zalviso drug product.
	Under the terms of the Services Agreement, the Company has agreed to purchase, subject to Patheon’s continued material compliance with the terms of the Services Agreement, all of its Product requirements for the United States, Canada and Mexico from Patheon during the Initial Term of the Services Agreement (as defined below), and at least eighty percent (80%) of its Product requirements for such territories after the Initial Term.
	The term of the Services Agreement extends until December 31, 2017, or the Initial Term, and will automatically renew thereafter for periods of two years, unless terminated by either party upon eighteen months’ prior written notice; provided, however, that the Services Agreement may not be terminated without cause prior to the end of the Initial Term.
	The Company also entered into a Capital Expenditure and Equipment Agreement, or the Capital Agreement. Under the terms of the Capital Agreement, as amended in January 2014, or the Amended Capital Agreement, the Company has made and has the option to make certain future modifications to Patheon’s Cincinnati facility and which would be the responsibility of the Company. If additional equipment and facility modifications are required to meet the Company’s Product needs, the Company may be required to contribute to the cost of such additional equipment and facility modifications.
	Expenditures associated with the aforementioned agreements are primarily driven by the potential commercial requirements and demand for the Company’s products, none of which have been approved for commercialization; accordingly, the amounts and timing of such future expenditures cannot be determined at this time.
	Grünenthal
	On December 16, 2013, the Company and Grünenthal entered into a License Agreement and Manufacturing Agreement. The License Agreement grants Grünenthal rights to commercialize Zalviso, the Company’s Product in the countries of the European Union, Switzerland, Liechtenstein, Iceland, Norway and Australia, or the Territory, for human use in pain treatment within or dispensed by hospitals, hospices, nursing homes and other medically-supervised settings, or the Field.
	Under the terms of the Manufacturing Agreement, the Company will manufacture and supply the Product for use in the Field for the Territory exclusively for Grünenthal. Grünenthal shall purchase from AcelRx, during the first five years after the effective date of the Manufacturing Agreement, 100% and thereafter 80% of Grünenthal’s and its sublicensees’ and distributors’ requirements of Product for use in the Field for the Territory. The Product will be supplied at the Company’s fully burdened manufacturing cost (as defined in the Manufacturing Agreement). The Manufacturing Agreement requires the Company to use commercially reasonable efforts to enter stand-by contracts with third parties providing significant supply and manufacturing services and under certain specified conditions permits Grünenthal to use a third party back-up manufacturer to manufacture the Product for Grünenthal’s commercial sale in the Territory.
	Unless earlier terminated, the Manufacturing Agreement continues in effect until the later of the expiration of the obligation of Grünenthal to make royalty and supply and trademark fee payments or the end of any transition period for manufacturing obligations due to the expiration or termination of the License Agreement. The Manufacturing Agreement is subject to earlier termination in connection with certain termination events in the License Agreement, in the event the parties mutually agree, by a party in the event of an uncured material breach by the other party or upon the bankruptcy or insolvency of either party.
	Under the Supply Agreement, the Company will exclusively manufacture and supply the Product to Grünenthal for the Field in the Territory.
	Expenditures associated with the aforementioned agreements are primarily driven by the potential commercial requirements and demand for the Company’s products, none of which are currently approved for commercial use; accordingly, the amounts and timing of such future expenditures cannot be determined at this time.

Accounting_Policies_by_Policy_

Accounting Policies, by Policy (Policies)	3 Months Ended
	Mar. 31, 2015
Accounting Policies [Abstract]
The Company [Policy Text Block]	The Company
	AcelRx Pharmaceuticals, Inc., or the Company or AcelRx, was incorporated in Delaware on July 13, 2005 as SuRx, Inc., and in January 2006, the Company changed its name to AcelRx Pharmaceuticals, Inc. The Company’s operations are based in Redwood City, California.
	AcelRx is a specialty pharmaceutical company focused on the development and commercialization of innovative therapies for the treatment of acute pain. AcelRx intends to commercialize its product candidates in the United States and license the development and commercialization rights to its product candidates for sale outside of the United States through strategic partnerships and collaborations. On July 25, 2014, the U.S. Food and Drug Administration, or FDA, issued a Complete Response Letter, or CRL, for the Company’s new drug application, or NDA, for Zalviso™ (sufentanil sublingual tablet system). In March 2015, the Company received a request from the FDA stating that in addition to the bench testing and two Human Factors studies it has performed in response to the CRL, a clinical trial is needed to assess the risk of inadvertent dispensing and overall risk of dispensing failures. On April 21, 2015, the Company submitted a request to the Division of Anesthesia, Analgesia, and Addiction Products, or the Division, of the FDA for a Type B meeting. On May 1, 2015, the Division notified the Company that the request for a meeting was denied and restated the Division’s view that a clinical study is required. The Company is consulting with regulatory, legal and clinical advisors to determine its next steps. The Company will be considering all options to determine a pathway forward for Zalviso, including the possibility of dispute resolution through one of the FDA prescribed pathways, as well as conducting additional clinical and Human Factors studies. The proposed indication for Zalviso is for the management of moderate-to-severe acute pain in adult patients in the hospital setting. Zalviso consists of sufentanil sublingual tablets delivered by the Zalviso System, a needle-free, handheld, patient-administered, pain management system (together, “Zalviso”).
	The Company has incurred recurring operating losses and negative cash flows from operating activities since inception and expects to continue to incur negative cash flows until its product candidates are approved for marketing in the United States and other countries, in which it has and intends to license its products, which may never occur. In previous years, prior to the commercial collaboration of Zalviso in Europe, AcelRx was considered a development stage company.
	The Company has one business activity, which is the development and commercialization of product candidates for the treatment of pain, and a single reporting and operating unit structure.
Basis of Accounting, Policy [Policy Text Block]	Basis of Presentation
	The accompanying unaudited condensed financial statements have been prepared in accordance with accounting principles generally accepted in the United States for interim financial information and the rules and regulations of the U.S. Securities and Exchange Commission, or SEC. Accordingly, they do not include all of the information and footnotes required by accounting principles generally accepted in the United States for complete financial statements. In the opinion of management, all adjustments (consisting of normal recurring adjustments) considered necessary for a fair presentation have been included.
	Operating results for the three months ended March 31, 2015, are not necessarily indicative of the results that may be expected for the year ending December 31, 2015. The condensed balance sheet as of December 31, 2014, was derived from the Company’s audited financial statements as of December 31, 2014, included in the Company’s Annual Report on Form 10-K filed with the SEC. These financial statements should be read in conjunction with the Company’s Annual Report on Form 10-K for the year ended December 31, 2014, which includes a broader discussion of the Company’s business and the risks inherent therein.
Use of Estimates, Policy [Policy Text Block]	Use of Estimates
	The preparation of financial statements in conformity with accounting principles generally accepted in the United States requires management to make estimates and assumptions that affect the amounts reported in the condensed financial statements and accompanying notes. Management evaluates its estimates on an ongoing basis including critical accounting policies. Estimates are based on historical experience and on various other market-specific and other relevant assumptions that the Company believes to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities that are not readily apparent from other sources. Actual results could differ from those estimates.
New Accounting Pronouncements, Policy [Policy Text Block]	Recently Issued Accounting Standards
	There have been no recent accounting pronouncements or changes in accounting pronouncements during the three months ended March 31, 2015, as compared to the recent accounting pronouncements described in the Company’s Form 10-K for the year ended December 31, 2014, that are of significance, or potential significance to the Company.

Note_2_Investments_and_Fair_Va1

Note 2 - Investments and Fair Value Measurement (Tables)	3 Months Ended
	Mar. 31, 2015
Investments And Fair Value Measurement Disclosure [Abstract]
Cash, Cash Equivalents and Investments [Table Text Block]		As of March 31, 2015
		Amortized Cost				Gross Unrealized		Gross Unrealized			Fair
						Gains		Losses			Value
	Cash and cash equivalents:
	Cash	$	49,097			$	—	$	—		$	49,097
	Money market funds		47				—		—			47
	Total cash and cash equivalents		49,144				—		—			49,144
	Marketable securities:
	U.S. government agency securities		15,293				1		—		$	15,294
	Total marketable securities		15,293				1		—		$	15,294
	Total cash, cash equivalents and investments	$	64,437			$	1	$	—		$	64,438
		As of December 31, 2014
		Amortized Cost				Gross Unrealized		Gross Unrealized			Fair
						Gains		Losses			Value
	Cash and cash equivalents:
	Cash	$	60,005			$	—	$	—		$	60,005
	Money market funds		33				—		—			33
	Total cash and cash equivalents		60,038				—		—		$	60,038
	Marketable securities:
	U.S. government agency securities		15,316				—		(4	)		15,312
	Total marketable securities		15,316				—		(4	)	$	15,312
	Total cash, cash equivalents and investments	$	75,354			$	—	$	(4	)	$	73,350
Fair Value Measurements, Recurring and Nonrecurring [Table Text Block]		As of March 31, 2015
		Fair Value				Level I		Level II			Level III
	Assets
	Money market funds	$	47			$	47	$	—		$	—
	U.S. government agency obligations		15,294				—		15,294			—
	Total assets measured at fair value	$	15,341			$	47	$	15,294		$	—
	Liabilities
	PIPE warrants	$	848				—		—		$	848
	Contingent put option liability		307				—		—			307
	Total liabilities measured at fair value	$	1,155			$	—	$	—		$	1,155
		As of December 31, 2014
		Fair Value				Level I		Level II			Level III
	Assets
	Money market funds	$	33			$	33	$	—		$	—
	U.S. government agency obligations		15,312				—		15,312			—
	Total assets measured at fair value	$	15,345			$	33	$	15,312		$	—
	Liabilities
	PIPE warrants	$	5,577				—		—		$	5,577
	Contingent put option liability	$	282				—		—		$	282
	Total liabilities measured at fair value	$	5,859			$	—	$	—		$	5,859
Fair Value of Warrants [Table Text Block]	Market price	$	3.86
	Exercise price	$	3.4
	Risk-free interest rate		0.89	%
	Expected volatility		61	%
	Expected life (in years)		2.7
	Expected dividend yield		0	%
	Market price	$	6.73
	Exercise price	$	3.4
	Risk-free interest rate		1.1	%
	Expected volatility		61	%
	Expected life (in years)		2.92
	Expected dividend yield		0	%
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block]				Three Months
				Ended
				March 31,
				2015
	Fair value—beginning of period		$	5,859
	Change in fair value of PIPE warrants			(4,729	)
	Change in fair value of contingent put option associated with Amended Loan Agreement with Hercules			25
	Fair value—end of period		$	1,155
		Three Months
		Ended
		March 31,
		2014
	Fair value—beginning of period	$	13,445
	Change in fair value of PIPE warrants		684
	Change in fair value of contingent put option associated with Original Loan Agreement with Hercules		(38	)
	Fair value—end of period	$	14,091

Note_6_Stockbased_Compensation1

Note 6 - Stock-based Compensation (Tables)	3 Months Ended
	Mar. 31, 2015
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Schedule of Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Table Text Block]		Three Months Ended
		March 31,
		2015		2014
	Expenses:
	Research and development	$	702	$	479
	General and administrative		836		496
	Total stock-based compensation expense	$	1,538	$	975

Note_8_Net_Loss_Per_Share_of_C1

Note 8 - Net Loss Per Share of Common Stock (Tables)	3 Months Ended
	Mar. 31, 2015
Earnings Per Share [Abstract]
Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]		Three Months Ended
		March 31,
		2015			2014
	Numerator
	Net loss used to compute net loss per share:
	Basic	$	(10,026	)	$	(9,631	)
	Adjustments for change in fair value of warrant liability		(2,186	)		—
	Diluted	$	(12,212	)	$	(9,631	)
	Denominator
	Weighted average shares outstanding used to compute net loss per share:
	Basic		43,873,108			43,190,409
	Dilutive effect of warrants		553,349			—
	Diluted		44,426,457			43,190,409
	Net loss per share — basic	$	(0.23	)	$	(0.22	)
	Net loss per share — diluted	$	(0.27	)	$	(0.22	)
Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table Text Block]		March 31,
		2015			2014
	Stock options to purchase common stock		5,582,360			5,083,428
	Restricted stock units		—			—
	Common stock warrants		692,611			1,674,669

Note_2_Investments_and_Fair_Va2

Note 2 - Investments and Fair Value Measurement (Details) (USD $)	3 Months Ended		12 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Investments And Fair Value Measurement Disclosure [Abstract]
Available-for-Sale Securities, Gross Unrealized Gain (Loss), Accumulated in Investments	$0		$0
Other than Temporary Impairment Losses, Investments, Available-for-sale Securities	0		0
Available-for-sale Securities, Accumulated Gross Unrealized Gain (Loss), before Tax	0		0
Other Comprehensive Income (Loss), Transfers from Held-to-maturity to Available-for-Sale Securities, Net of Tax	$0	$0

Note_2_Investments_and_Fair_Va3

Note 2 - Investments and Fair Value Measurement (Details) - Summary of Cash, Cash Equivalents and Investments (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Cash and cash equivalents:
Amortized Cost	$64,437	$75,354
Gross Unrealized Gains	1
Gross Unrealized Losses		-4
Fair Value	64,438	73,350
Cash and Cash Equivalents [Member] | Cash [Member]
Cash and cash equivalents:
Amortized Cost	49,097	60,005
Fair Value	49,097	60,005
Cash and Cash Equivalents [Member] | Money Market Funds [Member]
Cash and cash equivalents:
Amortized Cost	47	33
Fair Value	47	33
Cash and Cash Equivalents [Member]
Cash and cash equivalents:
Amortized Cost	49,144	60,038
Fair Value	49,144	60,038
Marketable Securities [Member] | U.S. Government Agency Securities [Member]
Cash and cash equivalents:
Amortized Cost	15,293	15,316
Gross Unrealized Gains	1
Gross Unrealized Losses		-4
Fair Value	15,294	15,312
Marketable Securities [Member]
Cash and cash equivalents:
Amortized Cost	15,293	15,316
Gross Unrealized Gains	1
Gross Unrealized Losses		-4
Fair Value	$15,294	$15,312

Note_2_Investments_and_Fair_Va4

Note 2 - Investments and Fair Value Measurement (Details) - Fair Value of Financial Assets and Liabilities by Level within Fair Value Hierarchy (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Assets
Total assets measured at fair value	$15,341	$15,345
Liabilities
Total liabilities measured at fair value	1,155	5,859
PIPE Warrants [Member] | Fair Value, Inputs, Level 3 [Member]
Liabilities
Total liabilities measured at fair value		5,577
PIPE Warrants [Member]
Liabilities
Total liabilities measured at fair value		5,577
Contingent Put Option Liability [Member] | Fair Value, Inputs, Level 3 [Member]
Liabilities
Total liabilities measured at fair value	307	282
Contingent Put Option Liability [Member]
Liabilities
Total liabilities measured at fair value	307	282
Money Market Funds [Member] | Fair Value, Inputs, Level 1 [Member]
Assets
Total assets measured at fair value	47	33
Money Market Funds [Member]
Assets
Total assets measured at fair value	47	33
U.S. Government Agency Obligations [Member] | Fair Value, Inputs, Level 2 [Member]
Assets
Total assets measured at fair value	15,294	15,312
U.S. Government Agency Obligations [Member]
Assets
Total assets measured at fair value	15,294	15,312
Fair Value, Inputs, Level 1 [Member]
Assets
Total assets measured at fair value	47	33
Fair Value, Inputs, Level 2 [Member]
Assets
Total assets measured at fair value	15,294	15,312
Fair Value, Inputs, Level 3 [Member] | PIPE Warrants [Member]
Liabilities
Total liabilities measured at fair value	848
Fair Value, Inputs, Level 3 [Member]
Liabilities
Total liabilities measured at fair value	1,155	5,859
PIPE Warrants [Member]
Liabilities
Total liabilities measured at fair value	$848

Note_2_Investments_and_Fair_Va5

Note 2 - Investments and Fair Value Measurement (Details) - Assumptions Used in Black-Scholes Option Pricing Model to Estimate Fair Value of Pipe Warrants (USD $)	3 Months Ended	12 Months Ended
	Mar. 31, 2015	Dec. 31, 2014
Assumptions Used in Black-Scholes Option Pricing Model to Estimate Fair Value of Pipe Warrants [Abstract]
Market price (in Dollars per share)	$3.86	$6.73
Exercise price (in Dollars per share)	$3.40	$3.40
Risk-free interest rate	0.89%	1.10%
Expected volatility	61.00%	61.00%
Expected life (in years)	2 years 255 days	2 years 335 days
Expected dividend yield	0.00%	0.00%

Note_2_Investments_and_Fair_Va6

Note 2 - Investments and Fair Value Measurement (Details) - Summary of Changes in Fair Value of Level III Financial Liabilities (Fair Value, Inputs, Level 3 [Member], USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value—beginning of period	$5,859	$13,445
Change in fair value of PIPE warrants	-4,729	684
Fair value—end of period	1,155	14,091
Amended Loan Agreement With Hercules [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Change in fair value of contingent put option	25
Hercules 2011 Loan and Security Agreement [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Change in fair value of contingent put option		($38)

Note_3_Collaboration_Agreement1

Note 3 - Collaboration Agreement (Details) (USD $)	1 Months Ended	3 Months Ended
	Dec. 31, 2013	Mar. 31, 2015	Sep. 30, 2014	Mar. 31, 2014
Note 3 - Collaboration Agreement (Details) [Line Items]
Revenue Recognition, Milestone Method, Revenue Recognized	$30,000,000
undefined		15,000,000
Revenue Recognition, Milestone Method, Agreed Additional Amount Based on Efforts and Targets		200,000,000
Manufacturing Agreement, Percentage for Five Years		100.00%
Manufacturing Agreement, Percentage Therafter		80.00%
Potential Milestone Payments, Related to Net Sales Target		171,500,000
Based upon Successful Regulatory and Product Development Efforts [Member]
Note 3 - Collaboration Agreement (Details) [Line Items]
Revenue Recognition, Milestone Method, Agreed Additional Amount Based on Efforts and Targets		28,500,000
Based upon Net Sales Target Achievements [Member]
Note 3 - Collaboration Agreement (Details) [Line Items]
Revenue Recognition, Milestone Method, Agreed Additional Amount Based on Efforts and Targets		171,500,000
Zalviso [Member] | Europe [Member]
Note 3 - Collaboration Agreement (Details) [Line Items]
Revenue Recognition, Milestone Method, Revenue Recognized		20,000,000
Zalviso [Member]
Note 3 - Collaboration Agreement (Details) [Line Items]
Revenue Recognition, Milestone Method, Revenue Recognized		28,500,000
Milestone Payments Received			5,000,000
Research and Development Services [Member]
Note 3 - Collaboration Agreement (Details) [Line Items]
Deferred Revenue, Revenue Recognized		181,000		95,000
Deferred Revenue		$2,200,000

Note_4_Longterm_Debt_Details

Note 4 - Long-term Debt (Details) (USD $)	3 Months Ended		12 Months Ended			1 Months Ended		0 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014		Dec. 31, 2011	Dec. 31, 2013	Jun. 30, 2011	Dec. 16, 2013	Jun. 16, 2014	Sep. 24, 2014	Jun. 29, 2011
Note 4 - Long-term Debt (Details) [Line Items]
Debt Conversion, Converted Instrument, Warrants or Options Issued (in Shares)					274,508
Common Stock Warrants Exercised (in Shares)	847,058
Final Repayment Fee for Early Repayment of Facility			$1,700,000
Fair Value of Contingent Put Option Liability	307,000		282,000	[1]
Interest Expense	806,000	472,000
After December 16, 2014, but Prior to December 16, 2015 [Member] | Hercules Loan and Security Agreement [Member]
Note 4 - Long-term Debt (Details) [Line Items]
Prepayment Charge of Term Loan, Percentage			2.00%
After December 16, 2015 [Member] | Hercules Loan and Security Agreement [Member]
Note 4 - Long-term Debt (Details) [Line Items]
Prepayment Charge of Term Loan, Percentage			1.00%
Hercules Warrants [Member] | Hercules Loan and Security Agreement [Member]
Note 4 - Long-term Debt (Details) [Line Items]
Warrant Exercisable Term					7 years
Hercules Warrants [Member]
Note 4 - Long-term Debt (Details) [Line Items]
Warrant Exercisable Term						5 years
Debt Conversion, Converted Instrument, Warrants or Options Issued (in Shares)							274,508
Investment Warrants, Exercise Price (in Dollars per share)			$6.79			$6.79	$3.06
Common Stock Warrants Exercised (in Shares)			176,730			176,730
Minimum [Member] | Hercules Loan and Security Agreement [Member]
Note 4 - Long-term Debt (Details) [Line Items]
Prepayment Charges for Accelerated Repayment of Credit Facility			1.00%
Maximum [Member] | Hercules Loan and Security Agreement [Member]
Note 4 - Long-term Debt (Details) [Line Items]
Prepayment Charges for Accelerated Repayment of Credit Facility			3.00%
Prime Rate [Member] | Amended and Restated Loan and Security Agreement [Member]
Note 4 - Long-term Debt (Details) [Line Items]
Debt Instrument, Interest Rate, Effective Percentage			9.10%
Debt Instrument, Basis Spread on Variable Rate			5.25%
First Tranche [Member] | Hercules Loan and Security Agreement [Member]
Note 4 - Long-term Debt (Details) [Line Items]
Debt Instrument, Face Amount							10,000,000
First Tranche [Member] | Amended and Restated Loan and Security Agreement [Member]
Note 4 - Long-term Debt (Details) [Line Items]
Debt Instrument, Face Amount								15,000,000
Repayments of Long-term Debt								8,600,000
Second Tranche [Member] | Hercules Loan and Security Agreement [Member]
Note 4 - Long-term Debt (Details) [Line Items]
Debt Instrument, Face Amount					10,000,000
Second Tranche [Member] | Amended and Restated Loan and Security Agreement [Member]
Note 4 - Long-term Debt (Details) [Line Items]
Debt Instrument, Face Amount									10,000,000
Third Tranche [Member] | Amended and Restated Loan and Security Agreement [Member]
Note 4 - Long-term Debt (Details) [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity										15,000,000
Hercules Loan and Security Agreement [Member]
Note 4 - Long-term Debt (Details) [Line Items]
Debt Instrument, Face Amount											20,000,000
Number of Tranches for Loan and Security Agreement							2
Debt Instrument, Interest Rate, Stated Percentage					8.50%
Investment Warrants, Exercise Price (in Dollars per share)							$3.06
Convertible Debt			5,000,000
Debt Instrument, Convertible, Conversion Ratio, Computation, Percentage Used in Numerator			103.00%
Debt Instrument, Convertible, Conversion Ratio, Amount Used in Denominator			9.3
Additional Default Interest Rate			5.00%
Fair Value of Contingent Put Option Liability	307,000		282,000					32,000
Long-term Line of Credit	25,100,000
Interest Expense	800,000
Amended and Restated Loan and Security Agreement [Member]
Note 4 - Long-term Debt (Details) [Line Items]
Number of Tranches for Loan and Security Agreement								3
Line of Credit Facility, Maximum Borrowing Capacity								40,000,000
Debt Instrument, Fair Value Disclosure			24,900,000
Debt Instrument, Periodic Payment Terms, Balloon Payment to be Paid			$1,700,000
[1]	The condensed balance sheet as of December 31, 2014 has been derived from the audited financial statements as of that date included in the Company's Annual Report on Form 10-K for the year ended December 31, 2014.

Note_5_Warrants_Details

Note 5 - Warrants (Details) (USD $)	3 Months Ended	12 Months Ended	1 Months Ended		12 Months Ended		1 Months Ended
In Millions, except Share data, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2011	Dec. 31, 2013	Jun. 30, 2011	Dec. 31, 2014	Dec. 31, 2013	Jun. 30, 2012
Note 5 - Warrants (Details) [Line Items]
Common Stock Warrants Exercised	847,058
Debt Conversion, Converted Instrument, Warrants or Options Issued		274,508
Stock Issued During Period Shares Common Stock Warrants Exercised	527,101
Hercules Warrants [Member]
Note 5 - Warrants (Details) [Line Items]
Class of Warrant or Right, Outstanding	176,730
Common Stock Warrants Exercised			176,730		176,730
Investment Warrants, Exercise Price (in Dollars per share)			$6.79	$3.06	$6.79
Warrant Exercisable Term			5 years
Fair Value of Warrant on Date of Issuance (in Dollars)			$1.10			$1.10
Derivative, Price Risk Option Strike Price (in Dollars per Share)			$6.79			$6.79
Class of Warrant or Right, Exercise Price of Warrants or Rights (in Dollars per share)			$9.67			$9.67
Class of Warrant or Right Fair Value Assumption Risk Free Interest Rate			1.55%			1.55%
Class of Warrant or Right Fair Value Assumption Stock Volatility			71.00%			71.00%
Class of Warrant or Right Fair Value Assumption Expected Dividend Yield			0.00%			0.00%
Debt Conversion, Converted Instrument, Warrants or Options Issued				274,508
Stock Issued During Period Shares Common Stock Warrants Exercised						183,404
PIPE Warrants [Member]
Note 5 - Warrants (Details) [Line Items]
Class of Warrant or Right, Outstanding							2,630,103
Investment Warrants, Exercise Price (in Dollars per share)							$3.40
Warrant Exercisable Term	6 months
Warrants Vesting Condition Description	50%
Series Warrants [Member] | Common Stock [Member]
Note 5 - Warrants (Details) [Line Items]
Class of Warrant or Right, Outstanding	3,425
2012 Private Placement [Member]
Note 5 - Warrants (Details) [Line Items]
Class of Warrant or Right, Outstanding	512,456
Fair Value of Warrant Upon Execution of Securities Purchase Agreement (in Dollars)	5.8
Estimated Fair Value of Warrant (in Dollars)	0.8
Other Income (in Dollars)	2.2

Note_6_Stockbased_Compensation2

Note 6 - Stock-based Compensation (Details)	Mar. 31, 2015
Note 6 - Stock-based Compensation (Details) [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant	2,603,962
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	5,582,360
Restricted Stock Units (RSUs) [Member]
Note 6 - Stock-based Compensation (Details) [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number	0

Note_6_Stockbased_Compensation3

Note 6 - Stock-based Compensation (Details) - Employee Stock Purchase Plan (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Expenses:
Stock-based compensation expense	$1,538	$975
Research and Development Expense [Member]
Expenses:
Stock-based compensation expense	702	479
General and Administrative Expense [Member]
Expenses:
Stock-based compensation expense	$836	$496

Note_7_Restructuring_Costs_Det

Note 7 - Restructuring Costs (Details) (USD $)	3 Months Ended
	Mar. 31, 2015
Note 7 - Restructuring Costs (Details) [Line Items]
Restructuring and Related Cost, Number of Positions Eliminated	19
Restructuring and Related Cost, Number of Positions Eliminated, Period Percent	36.00%
Restructuring Charges	$754,000
Restructuring Reserve, Current	754,000
Restructuring Charges [Member]
Note 7 - Restructuring Costs (Details) [Line Items]
Restructuring Charges	$754,000

Note_8_Net_Loss_Per_Share_of_C2

Note 8 - Net Loss Per Share of Common Stock (Details) - Computation of Basic and Diluted Net Loss Per Share of Common Stock (USD $)	3 Months Ended
In Thousands, except Share data, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Net loss used to compute net loss per share:
Basic	($10,026)	($9,631)
Adjustments for change in fair value of warrant liability	-2,186
Diluted	($12,212)	($9,631)
Weighted average shares outstanding used to compute net loss per share:
Basic	43,873,108	43,190,409
Dilutive effect of warrants	553,349
Diluted	44,426,457	43,190,409
Net loss per share — basic	($0.23)	($0.22)
Net loss per share — diluted	($0.27)	($0.22)

Note_8_Net_Loss_Per_Share_of_C3

Note 8 - Net Loss Per Share of Common Stock (Details) - Outstanding Shares of Common Stock Equivalents Excluded from Computation of Diluted Net Loss Per Share	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Stock Options to Purchase Common Stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Shares of common stock equivalents excluded from the computation of diluted net loss per share of common stock	5,582,360	5,083,428
Common Stock Warrants [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Shares of common stock equivalents excluded from the computation of diluted net loss per share of common stock	692,611	1,674,669

Note_9_Manufacturing_Agreement1

Note 9 - Manufacturing Agreements (Details)	3 Months Ended
	Mar. 31, 2015
Manufacturing Agreement [Abstract]
Annual Product World Wide Manufacturing Requirement Percentage	80.00%
Service Agreements Expiration Date	31-Dec-17
Service Agreement Renewal Period	2 years
Agreement Termination Notice Period	18 months
Product Purchased from AcelRx Through December 2017, Percentage	100.00%
Product Purchased from AcelRx After December 2017, Percentage	80.00%