Talphera (TLPH) 10-Q 4 Aug 15 2015 Q2 Quarterly report Financial data

Document And Entity Information

Document And Entity Information - shares	6 Months Ended
	Jun. 30, 2015	Jul. 21, 2015
Document and Entity Information [Abstract]
Entity Registrant Name	ACELRX PHARMACEUTICALS INC
Document Type	10-Q
Current Fiscal Year End Date	--12-31
Entity Common Stock, Shares Outstanding		44,374,509
Amendment Flag	false
Entity Central Index Key	1,427,925
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Accelerated Filer
Entity Well-known Seasoned Issuer	No
Document Period End Date	Jun. 30, 2015
Document Fiscal Year Focus	2,015
Document Fiscal Period Focus	Q2

Condensed Balance Sheets (Curre

Condensed Balance Sheets (Current Period Unaudited) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014	[1]
Current Assets:
Cash and cash equivalents	$ 35,842	$ 60,038
Short-term investments	15,353	15,312
Prepaid expenses and other current assets	2,324	948
Total current assets	53,519	76,298
Property and equipment, net	9,715	9,818
Restricted cash	250	250
Other assets	76	81
Total Assets	63,560	86,447
Current Liabilities:
Accounts payable	1,597	2,431
Accrued liabilities	2,048	3,654
Deferred revenue, current portion	152	787
Long-term debt, current portion	9,509	6,859
Total current liabilities	13,306	13,731
Deferred rent	479	529
Long-term debt, net of current portion	13,623	18,046
Deferred revenue, net of current portion	1,594	1,626
Contingent put option liability	251	282
Warrant liability	916	5,577
Total liabilities	30,169	39,791
Stockholders’ Equity:
Common stock, $0.001 par value—100,000,000 shares authorized as of June 30, 2015 and December 31, 2014; 44,374,509 and 43,712,363 shares issued and outstanding as of June 30, 2015 and December 31, 2014	44	43
Additional paid-in capital	231,074	225,423
Accumulated deficit	(197,728)	(178,806)
Accumulated other comprehensive income (loss)	1	(4)
Total stockholders’ equity	33,391	46,656
Total Liabilities and Stockholders’ Equity	$ 63,560	$ 86,447
[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 (Curr3

Condensed Balance Sheets (Current Period Unaudited) (Parentheticals) - $ / shares	Jun. 30, 2015	Dec. 31, 2014	[1]
Common stock, par value (in Dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized	100,000,000	100,000,000
Common stock, shares issued	44,374,509	43,712,363
Common stock, shares outstanding	44,374,509	43,712,363
[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 Compreh

Condensed Statements of Comprehensive Loss (Unaudited) - Scenario, Unspecified [Domain] - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Revenue:
Contract	$ 1,438		$ 1,438
Collaboration agreement	486	$ 71	667	$ 166
Total revenue	1,924	71	2,105	166
Operating expenses:
Research and development	7,310	7,284	13,616	11,995
General and administrative	2,735	5,047	7,256	8,972
Restructuring costs	2		756
Total operating expenses	10,047	12,331	21,628	20,967
Loss from operations	(8,123)	(12,260)	(19,523)	(20,801)
Interest expense	(777)	(530)	(1,583)	(1,002)
Interest income and other income (expense), net	4	2,215	2,184	1,597
Net loss	(8,896)	(10,575)	(18,922)	(20,206)
Other comprehensive loss:
Unrealized gains (losses) on available-for-sale securities	1	(2)	5	(2)
Comprehensive loss	$ (8,895)	$ (10,577)	$ (18,917)	$ (20,208)
Net loss per share of common stock, basic (in Dollars per share)	$ (0.20)	$ (0.24)	$ (0.43)	$ (0.47)
Net loss per share of common stock, diluted (in Dollars per share)	$ (0.20)	$ (0.30)	$ (0.47)	$ (0.50)
Shares used in computing net loss per share of common stock, basic (in Shares)	44,343,270	43,333,210	44,109,488	43,262,204
Shares used in computing net loss per share of common stock, diluted – see Note 9 (in Shares)	44,343,270	44,310,166	44,397,471	43,774,033

Condensed Statements of Cash Fl

Condensed Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2015		Jun. 30, 2014
Cash flows from operating activities:
Net loss	$ (18,922)		$ (20,206)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	997		318
Amortization of premium/discount on investments, net	47		140
Interest expense related to debt financing	472		279
Restructuring costs	(756)
Stock-based compensation	2,649		1,869
Revaluation of put option and PIPE warrant liabilities	(2,148)		(1,719)
Changes in operating assets and liabilities:
Prepaid expenses and other assets	(1,376)		(23)
Accounts payable	(834)		457
Accrued liabilities	(850)		(871)
Deferred revenue	(667)		(167)
Deferred rent	(50)		(20)
Net cash used in operating activities	(21,438)		(19,943)
Cash flows from investing activities:
Purchase of property and equipment	(894)		(1,959)
Purchase of investments	(5,543)		(4,879)
Proceeds from maturity of investments	5,460		5,379
Net cash used in investing activities	(977)		(1,459)
Cash flows from financing activities:
Proceeds from issuance of long-term debt			10,000
Payment of long-term debt	(2,240)
Net proceeds from issuance of common stock through equity plans and exercise of warrants	459		729
Net cash (used in) provided by financing activities	(1,781)		10,729
Net decrease in cash and cash equivalents	(24,196)		(10,673)
Cash and cash equivalents—Beginning of period	60,038	[1]	88,401
Cash and cash equivalents—End of period	$ 35,842		$ 77,728
[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 Summa

Note 1 - Organization and Summary of Significant Accounting Policies	6 Months Ended
	Jun. 30, 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. AcelRx may also consider the option to enter into strategic partnerships for its product candidates in the United States. In March 2015, the Company began a pivotal Phase 3 study of ARX-04 (sufentanil sublingual tablet, 30 mcg), a proprietary, non-invasive, single-use tablet in a disposable, pre-filled, single-dose applicator, or SDA. This study, SAP301, is a multi-center, double-blind, placebo-controlled study that will evaluate the efficacy and safety of ARX-04 vs. placebo for the treatment of moderate-to-severe acute pain following ambulatory abdominal surgery. This study is fully enrolled and top-line data is expected early in the fourth quarter of 2015. The Company believes ARX-04 may be a candidate for use in a variety of medically supervised settings to manage moderate-to-severe acute pain, including in the emergency room, or for post-operative patients, following either short-stay or ambulatory surgery. 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 correspondence from the FDA stating that in addition to the bench testing and two Human Factors studies the Company had performed in response to the issues identified in the CRL, a clinical trial is needed to assess the risk of inadvertent dispensing and overall risk of dispensing failures. The Company has been granted a General Advice meeting with the Division of Anesthesia, Analgesia, and Addiction Products in early September 2015 to discuss the FDA’s request for an additional clinical trial and the Company’s planned response to the CRL. Pending the outcome of that meeting, the Company intends to finalize its plans to refile the NDA for Zalviso. 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, 15 mcg, 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. 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 and six months ended June 30, 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. Significant Accounting Policies The Company’s significant accounting policies are detailed in its Annual Report on Form 10-K for the year ended December 31, 2014. In addition, during the six months ended June 30, 2015, the Company has updated its revenue recognition policy to include Contract revenue, as discussed below. There are no other significant changes to the Company’s significant accounting policies from those previously disclosed in its Annual Report on Form 10-K. Revenue Recognition - Contract Revenue In May 2015, the Company entered into an award contract with the United States Army Medical Research and Materiel Command, or USAMRMC, to support the development of the Company’s product candidate, ARX-04. The contract provides for the reimbursement of qualified expenses for research and development activities as defined under the terms of the contract. Revenue under the contract is recognized when the related qualified research expenses are incurred. Recently Issued Accounting Standards In May 2014, the Financial Accounting Standards Board, or FASB, issued Accounting Standards Update No. 2014-09, Revenue from Contracts with Customers In April 2015, the FASB issued Accounting Standards Update No. 2015-03, Interest—Imputation of Interest

Note 2 - Investments and Fair V

Note 2 - Investments and Fair Value Measurement	6 Months Ended
	Jun. 30, 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 June 30, 2015 Amortized Cost Gross Unrealized Gross Unrealized Fair Cash and cash equivalents: Cash $ 35,839 $ — $ — $ 35,839 Money market funds 3 — — 3 Total cash and cash equivalents 35,842 — — 35,842 Marketable securities: U.S. government agency securities 15,352 1 — $ 15,353 Total marketable securities 15,352 1 — $ 15,353 Total cash, cash equivalents and investments $ 51,194 $ 1 $ — $ 51,195 As of December 31, 2014 Amortized Cost Gross Unrealized Gross Unrealized Fair 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 June 30, 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 June 30, 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 and six months ended June 30, 2015 and 2014. As of June 30, 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 June 30, 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 5 “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 June 30, 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 June 30, 2015 Fair Value Level I Level II Level III Assets Money market funds $ 3 $ 3 $ — $ — U.S. government agency obligations 15,353 — 15,353 — Total assets measured at fair value $ 15,356 $ 3 $ 15,353 $ — Liabilities PIPE warrants $ 916 — — $ 916 Contingent put option liability 251 — — 251 Total liabilities measured at fair value $ 1,167 $ — $ — $ 1,167 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 June 30, 2015: Market price $ 4.24 Exercise price $ 3.40 Risk-free interest rate 0.64 % Expected volatility 57.0 % Expected life (in years) 2.42 Expected dividend yield 0.0 % 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 $ 3.40 Risk-free interest rate 1.10 % Expected volatility 61.0 % Expected life (in years) 2.92 Expected dividend yield 0.0 % 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 and six months ended June 30, 2015 and June 30, 2014 (in thousands): Three Months Six Months Fair value—beginning of period $ 1,155 $ 5,859 Change in fair value of PIPE warrants 68 (4,661 ) Change in fair value of contingent put option associated with Original Loan Agreement with Hercules (56 ) (31 ) Fair value—end of period $ 1,167 $ 1,167 Three Months Six Months Fair value—beginning of period $ 14,091 $ 13,445 Change in fair value of PIPE warrants (2,507 ) (1,823 ) Change in fair value of contingent put option associated with Original Loan Agreement with Hercules 142 104 Fair value—end of period $ 11,726 $ 11,726

Note 3 - U.S. Department of Def

Note 3 - U.S. Department of Defense Contract	6 Months Ended
	Jun. 30, 2015
Contractors [Abstract]
Long-term Contracts or Programs Disclosure [Text Block]	3. U.S. Department of Defense Contract On May 11, 2015, the Company entered into an award contract supported by the United States Army Medical Research and Materiel Command, or USAMRMC, within the U.S. Department of Defense, or the DoD, in which the DoD agreed to provide up to $17.0 million to the Company in order to support the development of the Company’s product candidate, ARX-04 ( sufentanil sublingual tablet, 30 mcg), a proprietary, non-invasive, single-use tablet in a disposable, pre-filled SDA, for the treatment of moderate-to-severe acute pain. The DoD contract supports development of ARX-04 to perform Phase 3 clinical trials and manufacturing activities in order to submit an NDA to the FDA. Under the terms of the contract, the DoD will reimburse the Company for costs incurred for development, manufacturing and clinical costs outlined in the contract, including reimbursement for certain personnel and overhead expenses. The period of performance under the contract begins on May 11, 2015 and ends on November 10, 2016. The contract gives the DoD the option to extend the term of the contract and provide additional funding for the research. In addition, if ARX-04 is approved by the FDA, the DoD has the option to purchase a certain number of units of commercial product pursuant to the terms of the contract. Revenue is recognized based on expenses incurred by the Company in conducting research and development activities set forth in the agreement. Revenue attributable to the research and development performed under the DoD contract, recorded as contract revenue in the condensed statements of comprehensive loss, was $1.4 million for the three and six months ended June 30, 2015. There was no such revenue recognized for the three and six months ended June 30, 2014.

Note 4 - Collaboration Agreemen

Note 4 - Collaboration Agreement	6 Months Ended
	Jun. 30, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Collaborative Arrangement Disclosure [Text Block]	4. 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 MSA, and together with the License Agreement, 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 MSA, the Company will exclusively manufacture and supply the Product to Grünenthal for the Field in the Territory. The Agreements were amended on July 22, 2015, effective as of July 17, 2015. See Note 11 “Subsequent Events,” for further description. 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 was initially 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 (initially $171.5 million). As mentioned above, the Agreements were amended on July 22, 2015, effective as of July 17, 2015. See Note 11 “Subsequent Events,” for further description. 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. MSA Under the terms of the MSA, 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 MSA, 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, subject to certain caps (as defined in the MSA). The MSA 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 MSA 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 MSA 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 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 acute moderate-to-severe post-operative pain in adult patients. 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. This $15.0 million non-substantive milestone payment will be allocated across the four significant non-contingent performance deliverables identified in the Agreements, based on the relative estimated selling price method, upon approval of the MAA, if approved. The Agreements also include milestone payments related to specified net sales targets, initially totaling $171.5 million. As mentioned above, the Agreements were amended on July 22, 2015, effective as of July 17, 2015. See Note 11 “Subsequent Events,” for further description. 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 $486,000 and $667,000 of previously deferred revenue related to research and development services under the collaboration agreement during the three and six months ended June 30, 2015, respectively, and $71,000 and $166,000, of previously deferred revenue related to research and development services under the collaboration agreement during the three and six months ended June 30, 2014, respectively. As of June 30, 2015, the Company had a deferred revenue balance of $1.7 million. There were no milestone payments received or recognized under these Agreements during the three and six months ended June 30, 2015.

Note 5 - Long-term Debt

Note 5 - Long-term Debt	6 Months Ended
	Jun. 30, 2015
Disclosure Text Block [Abstract]
Long-term Debt [Text Block]	5. 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 6 “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 FDA. The Company did not receive FDA approval of Zalviso by August 1, 2015 and as such, did not have access to the third tranche under the Loan Agreement, as amended, or 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 6 “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 June 30, 2015 and December 31, 2014, the estimated fair value of the contingent put option liability was $251,000 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 June 30, 2015, the Company had outstanding borrowings under the Amended Loan Agreement of $23.1 million. Interest expense related to the Amended Loan Agreement was $0.8 million and $1.6 million for the three and six months June 30, 2015, respectively.

Note 6 - Warrants

Note 6 - Warrants	6 Months Ended
	Jun. 30, 2015
Warrants Disclosure [Abstract]
Warrants Disclosure [Text Block]	6. Warrants Series A Warrants As of June 30, 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 June 30, 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 June 30, 2015, the fair value of the PIPE warrants was estimated to be $0.9 million. The change in fair value for the three months ended June 30, 2015 was $0.1 million, which was recorded as other expense, and the change in fair value for the six months ended June 30, 2015 was $2.1 million, which was recorded as other income. In March 2015, PIPE warrants to purchase 847,058 shares were net exercised for 527,101 shares of common stock. As of June 30, 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 7 - Stock-based Compensati

Note 7 - Stock-based Compensation	6 Months Ended
	Jun. 30, 2015
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Disclosure of Compensation Related Costs, Share-based Payments [Text Block]	7. 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 Six Months Ended 2015 2014 2015 2014 Expenses: Research and development $ 629 $ 560 $ 1,331 $ 1,039 General and administrative 482 334 1,318 830 Total stock-based compensation expense $ 1,111 $ 894 $ 2,649 $ 1,869 As of June 30, 2015 there were 2,377,921 shares available for grant, 5,766,994 options outstanding and no restricted stock units outstanding under the Company’s 2011 Equity Incentive Plan.

Note 8 - Restructuring Costs

Note 8 - Restructuring Costs	6 Months Ended
	Jun. 30, 2015
Restructuring and Related Activities [Abstract]
Restructuring and Related Activities Disclosure [Text Block]	8. Restructuring C osts 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. Employee termination benefits related to this restructuring, are charged to restructuring costs in the Statements of Comprehensive Loss. Restructuring costs for the three and six months ended June 30, 2015 (in thousands): Three Months Ended Six Months Ended June 30, June 30, 2015 2014 2015 2014 Employee termination benefits $ 2 $ — $ 756 $ — Total restructuring costs $ 2 $ — $ 756 $ — The following table presents activities related to a cost reduction plan during the three and six months ended June 30, 2015 (in thousands): Employee severance and related costs Balance of restructuring liability at December 31, 2014 $ — Charges 754 Payments — Balance of restructuring liability at March 31, 2015 754 Charges 2 Payments (753 ) Balance of restructuring liability at June 30, 2015 $ 3 The Company anticipates the restructuring liability will be fully disbursed by December 31, 2015.

Note 9 - Net Loss Per Share of

Note 9 - Net Loss Per Share of Common Stock	6 Months Ended
	Jun. 30, 2015
Earnings Per Share [Abstract]
Earnings Per Share [Text Block]	9. 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 six months ended June 30, 2015, the PIPE warrants had a dilutive impact to net loss per share due to a lower share price at June 30, 2015, compared to the closing share price on December 31, 2014. Similarly, during the three and six months ended June 30, 2014, the PIPE warrants had a dilutive impact to net loss per share due to a lower share price at June 30, 2014, compared to the closing share price on March 31, 2014 and December 31, 2013. 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 six months ended June 30, 2015 and the three and six months ended June 30, 2014. There was no such dilutive impact for the PIPE warrants during the three months ended June 30, 2015, as the share price increased as compared to the closing share price on 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 and six months ended June 30, 2015 and 2014 (in thousands, except for share and per share amounts): Three Months Ended June 30, Six Months Ended June 30, 201 5 201 4 201 5 201 4 (in thousands, except share and per share amounts) Numerator Net loss used to compute net loss per share: Basic $ (8,896 ) $ (10,575 ) $ (18,922 ) $ (20,206 ) Adjustments for change in fair value of warrant liability — (2,507 ) (2,117 ) (1,823 ) Diluted $ (8,896 ) $ (13,082 ) $ (21,039 ) $ (22,029 ) Denominator Weighted average shares outstanding used to compute net loss per share: Basic 44,343,270 43,333,210 44,109,488 43,262,204 Dilutive effect of warrants — 976,956 287,983 511,829 Diluted 44,343,270 44,310,166 44,397,471 43,774,033 Net loss per share — basic $ (0.20 ) $ (0.24 ) $ (0.43 ) $ (0.47 ) Net loss per share — diluted $ (0.20 ) $ (0.30 ) $ (0.47 ) $ (0.50 ) 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: June 30, 2015 2014 Stock options to purchase common stock 5,766,994 5,160,416 Restricted stock units — — Common stock warrants 692,611 1,674,669

Note 10 - Manufacturing Agreeme

Note 10 - Manufacturing Agreements	6 Months Ended
	Jun. 30, 2015
Manufacturing Agreement [Abstract]
Manufacturing Agreement [Text Block]	10. 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 MSA, or the Agreements. 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. The Agreements were amended on July 22, 2015, effective as of July 17, 2015. See Note 11 “Subsequent Events,” for further description. Under the terms of the MSA, 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 MSA, 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 MSA). The MSA 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 MSA 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 MSA 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 MSA, 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.

Note 11 - Subsequent Events

Note 11 - Subsequent Events	6 Months Ended
	Jun. 30, 2015
Subsequent Events [Abstract]
Subsequent Events [Text Block]	11. Subsequent Events On July 22, 2015, the Company entered into amendments to the License Agreement, or the License Amendment, and the MSA, or the MSA Amendment, between the Company and Grünenthal, each effective as of July 17, 2015, and together with the License Agreement and the MSA, the Amended Agreements. In the MSA Amendment and the License Amendment, the parties amended the Product supply configurations and packaging of Product components and accessories, and associated pricing therefor, which the Company will manufacture and supply to Grünenthal for the Territory. As consideration for an increase in the pricing of the Product components and accessories as part of the agreed packaging configurations, the total milestone payments from Grünenthal contingent upon achieving specified net sales target milestones were reduced from a total of $171.5 million to $166.0 million. The parties also updated the development plan for the Product in the Territory, providing for additional near-term development costs to be paid by Grünenthal. On July 23, 2015, the Committee for Medicinal Products for Human Use, or CHMP, of the European Medicines Agency, or EMA, adopted a positive opinion for Zalviso. The opinion, while not binding, recommends marketing authorization for Zalviso for the management of acute moderate-to-severe post-operative pain in adult patients in a hospital setting. A decision by the European Commission on the approval of Zalviso is anticipated in late September or early October.

Accounting Policies, by Policy

Accounting Policies, by Policy (Policies)	6 Months Ended
	Jun. 30, 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. AcelRx may also consider the option to enter into strategic partnerships for its product candidates in the United States. In March 2015, the Company began a pivotal Phase 3 study of ARX-04 (sufentanil sublingual tablet, 30 mcg), a proprietary, non-invasive, single-use tablet in a disposable, pre-filled, single-dose applicator, or SDA. This study, SAP301, is a multi-center, double-blind, placebo-controlled study that will evaluate the efficacy and safety of ARX-04 vs. placebo for the treatment of moderate-to-severe acute pain following ambulatory abdominal surgery. This study is fully enrolled and top-line data is expected early in the fourth quarter of 2015. The Company believes ARX-04 may be a candidate for use in a variety of medically supervised settings to manage moderate-to-severe acute pain, including in the emergency room, or for post-operative patients, following either short-stay or ambulatory surgery. 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 correspondence from the FDA stating that in addition to the bench testing and two Human Factors studies the Company had performed in response to the issues identified in the CRL, a clinical trial is needed to assess the risk of inadvertent dispensing and overall risk of dispensing failures. The Company has been granted a General Advice meeting with the Division of Anesthesia, Analgesia, and Addiction Products in early September 2015 to discuss the FDA’s request for an additional clinical trial and the Company’s planned response to the CRL. Pending the outcome of that meeting, the Company intends to finalize its plans to refile the NDA for Zalviso. 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, 15 mcg, 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. 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 and six months ended June 30, 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.
Revenue Recognition, Policy [Policy Text Block]	Revenue Recognition - Contract Revenue In May 2015, the Company entered into an award contract with the United States Army Medical Research and Materiel Command, or USAMRMC, to support the development of the Company’s product candidate, ARX-04. The contract provides for the reimbursement of qualified expenses for research and development activities as defined under the terms of the contract. Revenue under the contract is recognized when the related qualified research expenses are incurred.
New Accounting Pronouncements, Policy [Policy Text Block]	Recently Issued Accounting Standards In May 2014, the Financial Accounting Standards Board, or FASB, issued Accounting Standards Update No. 2014-09, Revenue from Contracts with Customers In April 2015, the FASB issued Accounting Standards Update No. 2015-03, Interest—Imputation of Interest

Note 2 - Investments and Fair18

Note 2 - Investments and Fair Value Measurement (Tables)	6 Months Ended
	Jun. 30, 2015
Investments And Fair Value Measurement Disclosure [Abstract]
Cash, Cash Equivalents and Investments [Table Text Block]	As of June 30, 2015 Amortized Cost Gross Unrealized Gross Unrealized Fair Cash and cash equivalents: Cash $ 35,839 $ — $ — $ 35,839 Money market funds 3 — — 3 Total cash and cash equivalents 35,842 — — 35,842 Marketable securities: U.S. government agency securities 15,352 1 — $ 15,353 Total marketable securities 15,352 1 — $ 15,353 Total cash, cash equivalents and investments $ 51,194 $ 1 $ — $ 51,195 As of December 31, 2014 Amortized Cost Gross Unrealized Gross Unrealized Fair 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 June 30, 2015 Fair Value Level I Level II Level III Assets Money market funds $ 3 $ 3 $ — $ — U.S. government agency obligations 15,353 — 15,353 — Total assets measured at fair value $ 15,356 $ 3 $ 15,353 $ — Liabilities PIPE warrants $ 916 — — $ 916 Contingent put option liability 251 — — 251 Total liabilities measured at fair value $ 1,167 $ — $ — $ 1,167 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 $ 4.24 Exercise price $ 3.40 Risk-free interest rate 0.64 % Expected volatility 57.0 % Expected life (in years) 2.42 Expected dividend yield 0.0 % Market price $ 6.73 Exercise price $ 3.40 Risk-free interest rate 1.10 % Expected volatility 61.0 % Expected life (in years) 2.92 Expected dividend yield 0.0 %
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block]	Three Months Six Months Fair value—beginning of period $ 1,155 $ 5,859 Change in fair value of PIPE warrants 68 (4,661 ) Change in fair value of contingent put option associated with Original Loan Agreement with Hercules (56 ) (31 ) Fair value—end of period $ 1,167 $ 1,167 Three Months Six Months Fair value—beginning of period $ 14,091 $ 13,445 Change in fair value of PIPE warrants (2,507 ) (1,823 ) Change in fair value of contingent put option associated with Original Loan Agreement with Hercules 142 104 Fair value—end of period $ 11,726 $ 11,726

Note 7 - Stock-based Compensa19

Note 7 - Stock-based Compensation (Tables)	6 Months Ended
	Jun. 30, 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 Six Months Ended 2015 2014 2015 2014 Expenses: Research and development $ 629 $ 560 $ 1,331 $ 1,039 General and administrative 482 334 1,318 830 Total stock-based compensation expense $ 1,111 $ 894 $ 2,649 $ 1,869

Note 8 - Restructuring Costs (T

Note 8 - Restructuring Costs (Tables)	6 Months Ended
	Jun. 30, 2015
Restructuring and Related Activities [Abstract]
Restructuring and Related Costs [Table Text Block]	Three Months Ended Six Months Ended June 30, June 30, 2015 2014 2015 2014 Employee termination benefits $ 2 $ — $ 756 $ — Total restructuring costs $ 2 $ — $ 756 $ —
Schedule of Restructuring Reserve by Type of Cost [Table Text Block]	Employee severance and related costs Balance of restructuring liability at December 31, 2014 $ — Charges 754 Payments — Balance of restructuring liability at March 31, 2015 754 Charges 2 Payments (753 ) Balance of restructuring liability at June 30, 2015 $ 3

Note 9 - Net Loss Per Share o21

Note 9 - Net Loss Per Share of Common Stock (Tables)	6 Months Ended
	Jun. 30, 2015
Earnings Per Share [Abstract]
Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]	Three Months Ended June 30, Six Months Ended June 30, 201 5 201 4 201 5 201 4 (in thousands, except share and per share amounts) Numerator Net loss used to compute net loss per share: Basic $ (8,896 ) $ (10,575 ) $ (18,922 ) $ (20,206 ) Adjustments for change in fair value of warrant liability — (2,507 ) (2,117 ) (1,823 ) Diluted $ (8,896 ) $ (13,082 ) $ (21,039 ) $ (22,029 ) Denominator Weighted average shares outstanding used to compute net loss per share: Basic 44,343,270 43,333,210 44,109,488 43,262,204 Dilutive effect of warrants — 976,956 287,983 511,829 Diluted 44,343,270 44,310,166 44,397,471 43,774,033 Net loss per share — basic $ (0.20 ) $ (0.24 ) $ (0.43 ) $ (0.47 ) Net loss per share — diluted $ (0.20 ) $ (0.30 ) $ (0.47 ) $ (0.50 )
Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table Text Block]	June 30, 2015 2014 Stock options to purchase common stock 5,766,994 5,160,416 Restricted stock units — — Common stock warrants 692,611 1,674,669

Note 2 - Investments and Fair22

Note 2 - Investments and Fair Value Measurement (Details) - USD ($)	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014
Investments And Fair Value Measurement Disclosure [Abstract]
Available-for-Sale Securities, Gross Unrealized Gain (Loss), Accumulated in Investments	$ 0		$ 0		$ 0
Other than Temporary Impairment Losses, Investments, Available-for-sale Securities			0		$ 0
Other Comprehensive Income (Loss), Transfers from Held-to-maturity to Available-for-Sale Securities, Net of Tax	0	$ 0	0	$ 0
Available-for-sale Securities, Gross Realized Gain (Loss)	$ 0	$ 0	$ 0	$ 0

Note 2 - Investments and Fair23

Note 2 - Investments and Fair Value Measurement (Details) - Summary of Cash, Cash Equivalents and Investments - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Cash and cash equivalents:
Amortized Cost	$ 51,194	$ 75,354
Gross Unrealized Gains	1
Gross Unrealized Losses		(4)
Fair Value	51,195	73,350
Cash and Cash Equivalents [Member]
Cash and cash equivalents:
Amortized Cost	35,842	60,038
Fair Value	35,842	60,038
Cash and Cash Equivalents [Member] | Cash [Member]
Cash and cash equivalents:
Amortized Cost	35,839	60,005
Fair Value	35,839	60,005
Cash and Cash Equivalents [Member] | Money Market Funds [Member]
Cash and cash equivalents:
Amortized Cost	3	33
Fair Value	3	33
Marketable Securities [Member]
Cash and cash equivalents:
Amortized Cost	15,352	15,316
Gross Unrealized Gains	1
Gross Unrealized Losses		(4)
Fair Value	15,353	15,312
Marketable Securities [Member] | U.S. Government Agency Securities [Member]
Cash and cash equivalents:
Amortized Cost	15,352	15,316
Gross Unrealized Gains	1
Gross Unrealized Losses		(4)
Fair Value	$ 15,353	$ 15,312

Note 2 - Investments and Fair24

Note 2 - Investments and Fair Value Measurement (Details) - Fair Value of Financial Assets and Liabilities by Level within Fair Value Hierarchy - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Assets
Total assets measured at fair value	$ 15,356	$ 15,345
Liabilities
Total liabilities measured at fair value	1,167	5,859
Money Market Funds [Member]
Assets
Total assets measured at fair value	3	33
U.S. Government Agency Obligations [Member]
Assets
Total assets measured at fair value	15,353	15,312
PIPE Warrants [Member]
Liabilities
Total liabilities measured at fair value	916
Contingent Put Option Liability [Member]
Liabilities
Total liabilities measured at fair value	251	282
PIPE Warrants [Member]
Liabilities
Total liabilities measured at fair value		5,577
Fair Value, Inputs, Level 1 [Member]
Assets
Total assets measured at fair value	3	33
Fair Value, Inputs, Level 1 [Member] | Money Market Funds [Member]
Assets
Total assets measured at fair value	3	33
Fair Value, Inputs, Level 2 [Member]
Assets
Total assets measured at fair value	15,353	15,312
Fair Value, Inputs, Level 2 [Member] | U.S. Government Agency Obligations [Member]
Assets
Total assets measured at fair value	15,353	15,312
Fair Value, Inputs, Level 3 [Member]
Liabilities
Total liabilities measured at fair value	1,167	5,859
Fair Value, Inputs, Level 3 [Member] | PIPE Warrants [Member]
Liabilities
Total liabilities measured at fair value	916
Fair Value, Inputs, Level 3 [Member] | Contingent Put Option Liability [Member]
Liabilities
Total liabilities measured at fair value	$ 251	282
Fair Value, Inputs, Level 3 [Member] | PIPE Warrants [Member]
Liabilities
Total liabilities measured at fair value		$ 5,577

Note 2 - Investments and Fair25

Note 2 - Investments and Fair Value Measurement (Details) - Assumptions Used in Black-Scholes Option Pricing Model to Estimate Fair Value of Pipe Warrants - $ / shares	6 Months Ended	12 Months Ended
	Jun. 30, 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)	$ 4.24	$ 6.73
Exercise price (in Dollars per share)	$ 3.40	$ 3.40
Risk-free interest rate	0.64%	1.10%
Expected volatility	57.00%	61.00%
Expected life (in years)	2 years 153 days	2 years 335 days
Expected dividend yield	0.00%	0.00%

Note 2 - Investments and Fair26

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 ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value—beginning of period	$ 1,155	$ 14,091	$ 5,859	$ 13,445
Change in fair value of PIPE warrants	68	(2,507)	(4,661)	(1,823)
Fair value—end of period	1,167	11,726	1,167	11,726
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 associated with Original Loan Agreement with Hercules	$ (56)	$ 142	$ (31)	$ 104

Note 3 - U.S. Department of D27

Note 3 - U.S. Department of Defense Contract (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	May. 11, 2015
Note 3 - U.S. Department of Defense Contract (Details) [Line Items]
Government Contract Receivable					$ 17,000,000
Contracts Revenue	$ 1,438,000		$ 1,438,000
Government [Member]
Note 3 - U.S. Department of Defense Contract (Details) [Line Items]
Contracts Revenue	$ 1,400,000	$ 0	$ 1,400,000	$ 0

Note 4 - Collaboration Agreem28

Note 4 - Collaboration Agreement (Details) - USD ($)	1 Months Ended	3 Months Ended			6 Months Ended
	Dec. 31, 2013	Jun. 30, 2015	Sep. 30, 2014	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Note 4 - Collaboration Agreement (Details) [Line Items]
Revenue Recognition, Milestone Method, Revenue Recognized	$ 30,000,000
undefined		$ 15,000,000			$ 15,000,000
Revenue Recognition, Milestone Method, Agreed Additional Amount Based on Efforts and Targets		200,000,000			$ 200,000,000
Manufacturing Agreement, Percentage for Five Years					100.00%
Manufacturing Agreement, Percentage Therafter					80.00%
Proceeds from Royalties Received		0			$ 0
Based upon Successful Regulatory and Product Development Efforts [Member]
Note 4 - Collaboration Agreement (Details) [Line Items]
Revenue Recognition, Milestone Method, Agreed Additional Amount Based on Efforts and Targets		28,500,000			28,500,000
Based upon Net Sales Target Achievements [Member]
Note 4 - Collaboration Agreement (Details) [Line Items]
Revenue Recognition, Milestone Method, Agreed Additional Amount Based on Efforts and Targets		171,500,000			171,500,000
Research and Development Services [Member]
Note 4 - Collaboration Agreement (Details) [Line Items]
Deferred Revenue, Revenue Recognized		486,000		$ 71,000	667,000	$ 166,000
Deferred Revenue		$ 1,700,000			1,700,000
Zalviso [Member]
Note 4 - Collaboration Agreement (Details) [Line Items]
Revenue Recognition, Milestone Method, Revenue Recognized					28,500,000
Milestone Payments Received			$ 5,000,000
Zalviso [Member] | Europe [Member]
Note 4 - Collaboration Agreement (Details) [Line Items]
Revenue Recognition, Milestone Method, Revenue Recognized					$ 20,000,000

Note 5 - Long-term Debt (Detail

Note 5 - Long-term Debt (Details)

1 Months Ended

3 Months Ended

6 Months Ended

12 Months Ended

Dec. 31, 2013$ / sharesshares

Dec. 16, 2013USD ($)

Jun. 30, 2011USD ($)$ / sharesshares

Jun. 30, 2015USD ($)

Mar. 31, 2015shares

Jun. 30, 2014USD ($)

Jun. 30, 2015USD ($)

Jun. 30, 2014USD ($)

Dec. 31, 2014USD ($)$ / sharesshares

Dec. 31, 2011USD ($)shares

Sep. 24, 2014USD ($)

Jun. 16, 2014USD ($)

Jun. 29, 2011USD ($)

Note 5 - Long-term Debt (Details) [Line Items]

Debt Conversion, Converted Instrument, Warrants or Options Issued (in Shares) | shares

274,508

Repayments of Long-term Debt

$ 2,240,000

Common Stock Warrants Exercised (in Shares) | shares

847,058

Final Repayment Fee for Early Repayment of Facility

$ 1,700,000

Fair Value of Contingent Put Option Liability

$ 251,000

251,000

282,000

[1]

Interest Expense

777,000

$ 530,000

1,583,000

$ 1,002,000

Hercules Loan and Security Agreement [Member]

Note 5 - 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) | $ / shares

$ 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

$ 9.30

Additional Default Interest Rate

5.00%

Fair Value of Contingent Put Option Liability

$ 32,000

251,000

251,000

$ 282,000

Long-term Line of Credit

23,100,000

23,100,000

Hercules Loan and Security Agreement [Member] | After December 16, 2014, but Prior to December 16, 2015 [Member]

Note 5 - Long-term Debt (Details) [Line Items]

Prepayment Charge of Term Loan, Percentage

2.00%

Hercules Loan and Security Agreement [Member] | After December 16, 2015 [Member]

Note 5 - Long-term Debt (Details) [Line Items]

Prepayment Charge of Term Loan, Percentage

1.00%

Hercules Loan and Security Agreement [Member] | Prior to December 16, 2014 [Member]

Note 5 - Long-term Debt (Details) [Line Items]

Interest Expense

$ 800,000

$ 1,600,000

Amended and Restated Loan and Security Agreement [Member]

Note 5 - 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

Amended and Restated Loan and Security Agreement [Member] | Prime Rate [Member]

Note 5 - Long-term Debt (Details) [Line Items]

Debt Instrument, Interest Rate, Effective Percentage

9.10%

Debt Instrument, Basis Spread on Variable Rate

5.25%

Hercules Warrants [Member]

Note 5 - Long-term Debt (Details) [Line Items]

Warrant Exercisable Term

5 years

Debt Conversion, Converted Instrument, Warrants or Options Issued (in Shares) | shares

274,508

Investment Warrants, Exercise Price (in Dollars per share) | $ / shares

$ 6.79

$ 3.06

$ 6.79

Common Stock Warrants Exercised (in Shares) | shares

176,730

176,730

Hercules Warrants [Member] | Hercules Loan and Security Agreement [Member]

Note 5 - Long-term Debt (Details) [Line Items]

Warrant Exercisable Term

7 years

First Tranche [Member] | Hercules Loan and Security Agreement [Member]

Note 5 - 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 5 - 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 5 - 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 5 - 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 5 - Long-term Debt (Details) [Line Items]

Line of Credit Facility, Maximum Borrowing Capacity

$ 15,000,000

Minimum [Member] | Hercules Loan and Security Agreement [Member]

Note 5 - 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 5 - Long-term Debt (Details) [Line Items]

Prepayment Charges for Accelerated Repayment of Credit Facility

3.00%

[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 6 - Warrants (Details)

Note 6 - Warrants (Details) $ / shares in Units, $ in Millions	1 Months Ended			3 Months Ended		6 Months Ended	12 Months Ended
	Dec. 31, 2013USD ($)$ / sharesshares	Jun. 30, 2012$ / sharesshares	Jun. 30, 2011$ / sharesshares	Jun. 30, 2015USD ($)shares	Mar. 31, 2015shares	Jun. 30, 2015USD ($)shares	Dec. 31, 2014$ / sharesshares	Dec. 31, 2013USD ($)$ / sharesshares	Dec. 31, 2011shares
Note 6 - 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
Series Warrants [Member] | Common Stock [Member]
Note 6 - Warrants (Details) [Line Items]
Class of Warrant or Right, Outstanding				3,425		3,425
2012 Private Placement [Member]
Note 6 - Warrants (Details) [Line Items]
Class of Warrant or Right, Outstanding				512,456		512,456
Fair Value of Warrant Upon Execution of Securities Purchase Agreement (in Dollars) | $				$ 5.8		$ 5.8
Estimated Fair Value of Warrant (in Dollars) | $				0.9		0.9
Other Expenses (in Dollars) | $				$ 0.1
Other Income (in Dollars) | $						$ 2.1
Hercules Warrants [Member]
Note 6 - Warrants (Details) [Line Items]
Class of Warrant or Right, Outstanding				176,730		176,730
Common Stock Warrants Exercised	176,730						176,730
Investment Warrants, Exercise Price (in Dollars per share) | $ / shares	$ 6.79		$ 3.06				$ 6.79
Warrant Exercisable Term	5 years
Fair Value of Warrant on Date of Issuance (in Dollars) | $	$ 1.1							$ 1.1
Derivative, Price Risk Option Strike Price (in Dollars per Share) | $ / shares	6.79							6.79
Class of Warrant or Right, Exercise Price of Warrants or Rights (in Dollars per share) | $ / shares	$ 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 6 - Warrants (Details) [Line Items]
Class of Warrant or Right, Outstanding		2,630,103
Investment Warrants, Exercise Price (in Dollars per share) | $ / shares		$ 3.40
Warrant Exercisable Term						6 years
Warrants Vesting Condition Description						50%

Note 7 - Stock-based Compensa31

Note 7 - Stock-based Compensation (Details) - 2011 Equity Incentive Plan [Member]	Jun. 30, 2015shares
Note 7 - Stock-based Compensation (Details) [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant	2,377,921
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	5,766,994
Restricted Stock Units (RSUs) [Member]
Note 7 - Stock-based Compensation (Details) [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number	0

Note 7 - Stock-based Compensa32

Note 7 - Stock-based Compensation (Details) - Employee Stock Purchase Plan - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Expenses:
Stock-based compensation expense	$ 1,111	$ 894	$ 2,649	$ 1,869
Research and Development Expense [Member]
Expenses:
Stock-based compensation expense	629	560	1,331	1,039
General and Administrative Expense [Member]
Expenses:
Stock-based compensation expense	$ 482	$ 334	$ 1,318	$ 830

Note 8 - Restructuring Costs (D

Note 8 - Restructuring Costs (Details)	3 Months Ended
	Mar. 31, 2015
Restructuring and Related Activities [Abstract]
Restructuring and Related Cost, Number of Positions Eliminated	19
Restructuring and Related Cost, Number of Positions Eliminated, Period Percent	36.00%

Note 8 - Restructuring Costs 34

Note 8 - Restructuring Costs (Details) - Restructuring Costs - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Mar. 31, 2015	Jun. 30, 2015
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	$ 2	$ 754	$ 756
Employee Severance [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	$ 2		$ 756

Note 8 - Restructuring Costs 35

Note 8 - Restructuring Costs (Details) - Restructuring Activity - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Mar. 31, 2015	Jun. 30, 2015
Restructuring Activity [Abstract]
Balance of restructuring liability at	$ 3	$ 754	$ 3
Charges	2	$ 754	$ 756
Payments	$ (753)

Note 9 - Net Loss Per Share o36

Note 9 - Net Loss Per Share of Common Stock (Details) - Computation of Basic and Diluted Net Loss Per Share of Common Stock - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Net loss used to compute net loss per share:
Basic	$ (8,896)	$ (10,575)	$ (18,922)	$ (20,206)
Adjustments for change in fair value of warrant liability		(2,507)	(2,117)	(1,823)
Diluted	$ (8,896)	$ (13,082)	$ (21,039)	$ (22,029)
Weighted average shares outstanding used to compute net loss per share:
Basic	44,343,270	43,333,210	44,109,488	43,262,204
Dilutive effect of warrants		976,956	287,983	511,829
Diluted	44,343,270	44,310,166	44,397,471	43,774,033
Net loss per share — basic	$ (0.20)	$ (0.24)	$ (0.43)	$ (0.47)
Net loss per share — diluted	$ (0.20)	$ (0.30)	$ (0.47)	$ (0.50)

Note 9 - Net Loss Per Share o37

Note 9 - Net Loss Per Share of Common Stock (Details) - Outstanding Shares of Common Stock Equivalents Excluded from Computation of Diluted Net Loss Per Share - shares	6 Months Ended
	Jun. 30, 2015	Jun. 30, 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	5,766,994	5,160,416
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 10 - Manufacturing Agree38

Note 10 - Manufacturing Agreements (Details) - Jun. 30, 2015	Total
Manufacturing Agreement [Abstract]
Annual Product World Wide Manufacturing Requirement Percentage	80.00%
Service Agreements Expiration Date	Dec. 31, 2017
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%

Note 11 - Subsequent Events (De

Note 11 - Subsequent Events (Details) - USD ($) $ in Millions	Jul. 17, 2015	Jul. 16, 2015
Based upon Net Sales Target Achievements [Member] | Subsequent Event [Member]
Note 11 - Subsequent Events (Details) [Line Items]
Potential Milestone Payments, Related to Net Sales Target	$ 166	$ 171.5