Talphera (TLPH) 10-K 7 Mar 19 2018 FY Annual report Financial data

Document And Entity Information

Document And Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2018	Feb. 25, 2019	Jun. 29, 2018
Document Information [Line Items]
Entity Registrant Name	ACELRX PHARMACEUTICALS INC
Entity Central Index Key	1,427,925
Trading Symbol	acrx
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Well-known Seasoned Issuer	No
Entity Emerging Growth Company	false
Entity Small Business	true
Entity Common Stock, Shares Outstanding (in shares)		78,757,930
Entity Public Float			$ 177,225,920
Document Type	10-K
Document Period End Date	Dec. 31, 2018
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	FY
Amendment Flag	false
Entity Shell Company	false

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Assets
Cash and cash equivalents	$ 87,975	$ 52,902
Short-term investments	17,740	7,567
Accounts receivable, net	49	1,533
Tax receivable	352
Inventories	854	956
Prepaid expenses and other current assets	1,024	455
Total current assets	107,994	63,413
Property and equipment, net	11,483	11,051
Restricted cash	178	178
Long-term tax receivable	351	703
Other assets	527	207
Total Assets	120,533	75,552
Liabilities and Stockholders’ Equity (Deficit)
Accounts payable	2,070	1,424
Accrued liabilities	4,540	3,543
Long-term debt, current portion	8,611	7,727
Deferred revenue, current portion	315	362
Liability related to the sale of future royalties, current portion	392	604
Total current liabilities	15,928	13,660
Deferred rent, net of current portion	416	378
Long-term debt, net of current portion	3,380	11,369
Deferred revenue, net of current portion	3,148	3,463
Liability related to the sale of future royalties, net of current portion	93,287	82,984
Contingent put option liability	121	207
Total liabilities	116,280	112,061
Commitments and Contingencies
Stockholders’ Equity (Deficit):
Common stock, $0.001 par value—100,000,000 shares authorized as of December 31, 2018 and December 31, 2017; 78,757,930 and 50,899,154 shares issued and outstanding as of December 31, 2018 and December 31, 2017	78	51
Additional paid-in capital	349,194	261,310
Accumulated deficit	(345,019)	(297,870)
Total stockholders’ equity (deficit)	4,253	(36,509)
Total Liabilities and Stockholders’ Equity (Deficit)	$ 120,533	$ 75,552

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parentheticals) - $ / shares	Dec. 31, 2018	Dec. 31, 2017
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, authorized (in shares)	100,000,000	100,000,000
Common stock, issued (in shares)	78,757,930	50,899,154
Common stock, outstanding (in shares)	78,757,930	50,899,154

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Loss - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Revenue:
Revenue	$ 2,151,000	$ 7,995,000	$ 17,357,000
Operating costs and expenses:
Cost of goods sold	3,976,000	10,659,000	12,315,000
Research and development	13,137,000	19,409,000	21,402,000
General and administrative	20,765,000	16,609,000	15,597,000
Total operating costs and expenses	37,878,000	46,677,000	49,314,000
Loss from operations	(35,727,000)	(38,682,000)	(31,957,000)
Other expense:
Interest expense	(2,217,000)	(3,316,000)	(2,770,000)
Interest income and other income, net	1,138,000	510,000	918,000
Non-cash interest expense on liability related to sale of future royalties	(10,341,000)	(10,721,000)	(9,382,000)
Total other expense	(11,420,000)	(13,527,000)	(11,234,000)
Net loss before income taxes	(47,147,000)	(52,209,000)	(43,191,000)
Provision (benefit) for income taxes	2,000	(701,000)	(34,000)
Net loss	(47,149,000)	(51,508,000)	(43,157,000)
Other comprehensive (loss) income:
Unrealized (losses) gains on available for sale securities		(3,000)	4,000
Comprehensive loss	$ (47,149,000)	$ (51,511,000)	$ (43,153,000)
Net loss per share of common stock, basic and diluted (in dollars per share)	$ (0.81)	$ (1.10)	$ (0.95)
Shares used in computing net loss per share of common stock, basic and diluted –see Note 14 (in shares)	58,408,548	46,883,535	45,313,118
Collaboration Agreement Revenue [Member]
Revenue:
Revenue	$ 1,313,000	$ 7,143,000	$ 6,440,000
Contract and Other [Member]
Revenue:
Revenue	$ 838,000	$ 852,000	$ 10,917,000

Consolidated Statements of Stoc

Consolidated Statements of Stockholders' Equity (Deficit) - USD ($) $ in Thousands	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	AOCI Attributable to Parent [Member]	Total
Balance (in shares) at Dec. 31, 2015	45,273,772
Balance at Dec. 31, 2015	$ 45	$ 236,274	$ (203,205)	$ (1)	$ 33,113
Stock-based compensation		4,479			4,479
Modification of warrants		45			45
Issuance of common stock upon ESPP purchase (in shares)	60,018
Issuance of common stock upon ESPP purchase		179			179
Change in unrealized gains and losses on investments				4	4
Net loss			(43,157)		(43,157)
Balance (in shares) at Dec. 31, 2016	45,333,790
Balance at Dec. 31, 2016	$ 45	240,977	(246,362)	3	(5,337)
Stock-based compensation		4,294			4,294
Issuance of common stock upon ESPP purchase (in shares)	94,893
Issuance of common stock upon ESPP purchase		246			246
Change in unrealized gains and losses on investments				(3)	(3)
Net loss			(51,508)		(51,508)
Net proceeds from issuance of common stock in connection with equity financings (in shares)	5,401,099
Net proceeds from issuance of common stock in connection with equity financings	$ 6	15,688			15,694
Issuance of common stock upon exercise of stock options (in shares)	69,372
Issuance of common stock upon exercise of stock options		105			105
Net proceeds from issuance of common stock in connection with equity financings (in shares)	5,401,099
Balance (in shares) at Dec. 31, 2017	50,899,154
Balance at Dec. 31, 2017	$ 51	261,310	(297,870)		(36,509)
Stock-based compensation		5,168			5,168
Issuance of common stock upon ESPP purchase (in shares)	182,360
Issuance of common stock upon ESPP purchase		275			275
Change in unrealized gains and losses on investments
Net loss			(47,149)		(47,149)
Net proceeds from issuance of common stock in connection with equity financings (in shares)	27,364,301
Net proceeds from issuance of common stock in connection with equity financings	$ 27	81,498			$ 81,525
Issuance of common stock upon exercise of stock options (in shares)	135,385				135,385
Issuance of common stock upon exercise of stock options		401			$ 401
Net proceeds from issuance of common stock in connection with equity financings (in shares)	27,364,301
Issuance of common stock upon exercise of warrants (in shares)	176,730
Issuance of common stock upon exercise of warrants		542			542
Balance (in shares) at Dec. 31, 2018	78,757,930
Balance at Dec. 31, 2018	$ 78	$ 349,194	$ (345,019)		$ 4,253

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
CASH FLOWS FROM OPERATING ACTIVITIES:
Net loss	$ (47,149)	$ (51,508)	$ (43,157)
Adjustments to reconcile net loss to net cash used in operating activities:
Non-cash royalty revenue related to royalty monetization	(289)	(151)	(7)
Non-cash interest expense on liability related to royalty monetization	10,341	10,721	9,382
Depreciation and amortization	575	1,744	2,052
Non-cash interest expense related to debt financing	613	1,265	877
Stock-based compensation	5,168	4,294	4,479
Revaluation of put option and PIPE warrant liabilities	(86)	(205)	(767)
Loss on disposal and impairment of property and equipment		12
Inventory impairment charge		369
Other	(115)	(5)	17
Changes in operating assets and liabilities:
Accounts receivable	1,484	4,300	(2,547)
Inventories	102	920	(1,688)
Prepaid expenses and other assets	(850)	175	975
Tax receivable		(703)
Accounts payable	458	309	(437)
Accrued liabilities	922	(1,301)	639
Deferred revenue	(362)	(361)	989
Deferred rent	113	360	(202)
Net cash used in operating activities	(29,075)	(29,765)	(29,395)
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchase of property and equipment	(819)	(2,405)	(3,720)
Purchase of investments	(30,558)	(7,565)	(996)
Proceeds from maturities of investments	20,500		6,525
Net cash (used in) provided by investing activities	(10,877)	(9,970)	1,809
CASH FLOWS FROM FINANCING ACTIVITIES:
Payment of long-term debt	(7,718)	(3,514)
Payment of debt modification transaction costs		(204)	(205)
Net proceeds from issuance of common stock in connection with equity financings	81,525	15,694
Net proceeds from issuance of common stock through equity plans	1,218	351	179
Net cash provided by (used in) financing activities	75,025	12,327	(26)
NET INCREASE (DECREASE) IN CASH, CASH EQUIVALENTS AND RESTRICTED CASH	35,073	(27,408)	(27,612)
CASH, CASH EQUIVALENTS AND RESTRICTED CASH—Beginning of period	53,080	80,488	108,100
CASH, CASH EQUIVALENTS AND RESTRICTED CASH —End of period	88,153	53,080	80,488
SUPPLEMENTAL DISCLOSURES OF CASH FLOW INFORMATION:
Cash paid for interest	1,667	2,043	1,893
Income taxes paid (refunded)	2	2	(55)
NONCASH INVESTING AND FINANCING ACTIVITIES:
Modification of warrants for common stock			45
Purchases of property and equipment in Accounts payable	$ 410	$ 222	$ 532

Reconciliation of Cash, Cash Eq

Reconciliation of Cash, Cash Equivalents, and Restricted Cash	12 Months Ended
	Dec. 31, 2018
Notes to Financial Statements
Cash and Cash Equivalents Disclosure [Text Block]	The following table provides a reconciliation of cash, cash equivalents, and restricted cash reported within the consolidated balance sheets that sum to the total of the same such amounts shown in the consolidated statement of cash flows (in thousands): Year Ended December 31, 2018 2017 2016 CASH AND CASH EQUIVALENTS 87,975 52,902 80,310 RESTRICTED CASH 178 178 178 CASH, CASH EQUIVALENTS AND RESTRICTED CASH SHOWN IN STATEMENT OF CASH FLOWS $ 88,153 $ 53,080 $ 80,488 Amounts included in restricted cash represent letters of credit required to be maintained under the Company’s facility lease and corporate credit card agreements as security for performance under these agreements. The letters of credit are secured by certificates of deposit in amounts equal to the letters of credit. See notes to consolidated financial statements.

Note 1 - Organization and Summa

Note 1 - Organization and Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2018
Notes to Financial Statements
Basis of Presentation and Significant Accounting Policies [Text Block]	1. The Company AcelRx Pharmaceuticals, Inc., or the Company or AcelRx, was incorporated in Delaware on July 13, 2005 January 2006, AcelRx is a specialty pharmaceutical company focused on the development and commercialization of innovative therapies for use in medically supervised settings. DSUVIA (known as DZUVEO in Europe) and Zalviso, are November 2, 2018, June 2018, first 2019. not may one not DSUVIA DSUVIA, known as DZUVEO in Europe, approved by the FDA in November 2018, June 2018. DSUVIA was approved with a Risk Evaluation and Mitigation Strategy, or REMS, which restricts distribution to certified medically supervised healthcare settings in order to prevent respiratory depression resulting from accidental exposure. DSUVIA will only be distributed to facilities certified in the DSUVIA REMS program following attestation by an authorized representative to comply with appropriate dispensing and use restrictions of DSUVIA. To become certified, a healthcare setting will need to train their healthcare professionals on the proper use of DSUVIA and have the ability to manage respiratory depression. DSUVIA will not Zalviso Zalviso delivers 15 September 2013 July 25, 2014. IAP312, IAP312 August 2017, three 3 On December 16, 2013, July 17, 2015 September 20, 2016, September 2015, December 16, 2013, July 22, 2015, July 17, 2015. The Company has incurred recurring operating losses and negative cash flows from operating activities since inception. Although Zalviso has been approved for sale in Europe, on September 18, 2015, November 2018 first 2019. Except as the context otherwise requires, when we refer to "we," "our," "us," the "Company" or "AcelRx" in this document, we mean AcelRx Pharmaceuticals, Inc., and its consolidated subsidiary. “DSUVIA” and “DZUVEO” are trademarks, and “ACELRX” and “Zalviso” are registered trademarks, all owned by AcelRx Pharmaceuticals, Inc. This report also contains trademarks and trade names that are the property of their respective owners. Basis of Presentation The preparation of financial statements in conformity with generally accepted accounting principles requires management to make estimates and assumptions that affect the amounts reported in the Consolidated Financial Statements and the accompanying notes. Actual results could differ from those estimates. Reclassifications Certain prior year amounts in the Consolidated Financial Statements have been reclassified to conform to the current year's presentation. In particular, the amount reported in the Consolidated Statements of Cash Flows as “Noncash Investing and Financing Activities – Purchases of property and equipment in Accrued liabilities” has been reclassified to “Noncash Investing and Financing Activities – Purchases of property and equipment in Accounts payable” for the year ended December 31, 2017, December 31, 2016. Principles of Consolidation The Consolidated Financial Statements include the accounts of the Company and its wholly owned subsidiary, ARPI LLC, which was formed in September 2015 9 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 Consolidated 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 Cash, Cash Equivalents and Marketable Securities The Company considers all highly liquid investments with an original maturity (at date of purchase) of three All marketable securities are classified as available-for-sale and consist of U.S. government sponsored enterprise debt securities and commercial paper. These securities are carried at estimated fair value, which is based on quoted market prices or observable market inputs of almost identical assets, with unrealized gains and losses included in accumulated other comprehensive income (loss). The amortized cost of securities is adjusted for amortization of premiums and accretion of discounts to maturity. Such amortization and accretion is included in interest income or expense. The cost of securities sold is based on specific identification. The Company’s investments are subject to a periodic impairment review for other-than-temporary declines in fair value. The Company’s review includes the consideration of the cause of the impairment including the creditworthiness of the security issuers, the number of securities in an unrealized loss position, the severity and duration of the unrealized losses and the Company’s intent and ability to hold the investment for a period of time sufficient to allow for any anticipated recovery in the market value. When the Company determines that the decline in fair value of an investment is below its accounting basis and this decline is other-than-temporary, it reduces the carrying value of the security it holds and records a loss in the amount of such decline. Fair Value of Financial Instruments The Company measures and reports its cash equivalents, investments and financial liabilities at fair value. Fair value is defined as the exchange price that would be received for an asset or an exit price paid to transfer a liability in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. Valuation techniques used to measure fair value must maximize the use of observable inputs and minimize the use of unobservable inputs. The fair value hierarchy defines a three Level I—Unadjusted quoted prices in active markets for identical assets or liabilities; Level II—Inputs other than quoted prices included within Level I that are observable, unadjusted quoted prices in markets that are not Level III—Unobservable inputs that are supported by little or no The categorization of a financial instrument within the valuation hierarchy is based upon the lowest level of input that is significant to the fair value measurement. Segment Information The Company operates in a single segment, the development and commercialization of product candidates for the treatment of pain. The Company’s contract revenue relates to sales in the United States. The Company’s collaboration revenue relates to the Amended License Agreement with Grünenthal to commercialize Zalviso in the countries of the European Union, Switzerland, Liechtenstein, Iceland, Norway and Australia. Concentration of Risk The Company invests cash that is currently not The Company relies on a single third third To date, the Company has had only two two 100% December 31, 2018, 2017 2016. 100% 79% December 31, 2018, 2017, 71% December 31, 2016. The Company has not December 31, 2018 Accounts Receivable, Net The Company has receivables from its collaboration partner and the U.S. Department of Defense, or DoD. To date, the Company has not Inventories Inventories are valued at the lower of cost and net realizable value. Cost is determined using the first first third The Company's policy is to write down inventory that has become obsolete, inventory that has a cost basis in excess of its expected net realizable value and inventory in excess of expected requirements. The Company periodically evaluates the carrying value of inventory on hand for potential excess amount over demand using the same lower of cost or market approach as that used to value the inventory. Because the predetermined, contractual transfer prices the Company is receiving from Grünenthal are less than the direct costs of manufacturing, all Zalviso inventories are carried at net realizable value. Property and Equipment Property and equipment are stated at cost less accumulated depreciation and amortization. Depreciation is calculated using the straight-line method over the estimated useful lives of the assets, generally three five not Impairment of Long-Lived Assets The Company periodically assesses the impairment of long-lived assets and, if indicators of asset impairment exist, the Company assesses the recoverability of the affected long-lived assets by determining whether the carrying value of such assets can be recovered through an analysis of the undiscounted future expected operating cash flows. If impairment is indicated, the Company records the amount of such impairment for the excess of the carrying value of the asset over its estimated fair value. For example, if the Company is not may no September 30, 2015, $0.5 December 31, 2015, December 31, 2018, not Restricted Cash Under the Company’s facility lease and corporate credit card agreements, the Company is required to maintain letters of credit as security for performance under these agreements. The letters of credit are secured by certificates of deposit in amounts equal to the letters of credit, which are classified as restricted cash on the Consolidated Balance Sheets. Debt Issuance Costs Debt issuance costs, which are included in long-term debt, net of current portion, are amortized as interest expense over the contractual terms of the related credit facilities. Contingent put option The contingent put option associated with the Company’s loan and security agreement with Hercules Technology II, L.P. and Hercules Technology Growth Capital, Inc., collectively referred to as the Lenders, is recorded as a liability. Changes in the fair value of the contingent put option are recognized as interest income and other income, net in the Consolidated Statements of Comprehensive Loss. For additional information regarding the contingent put option, see Note 8 Warrants Warrants issued in connection with the Company’s Private Placement, completed in June 2012, 10 December 31, 2018, Revenue Recognition Beginning January 1, 2018, 606, Revenue from Contracts with Customers The Company generates revenue from collaboration agreements. These agreements typically include payments for upfront signing or license fees, cost reimbursements for development and manufacturing services, milestone payments, product sales, and royalties on licensee’s future product sales. The Company has entered into award contracts with U.S. Department of Defense, or the DoD, to support the development of DSUVIA. These contracts provide for the reimbursement of qualified expenses for research and development activities. Revenue under these arrangements is recognized when the related qualified research expenses are incurred. The Company is entitled to reimbursement of overhead costs associated with the study costs under the DoD arrangements. The Company estimates this overhead rate by utilizing forecasted expenditures. Final reimbursable overhead expenses are dependent on direct labor and direct reimbursable expenses throughout the life of each contract, which may In determining the appropriate amount of revenue to be recognized as it fulfills its obligations under its agreements, the Company performs the following steps: (i) identification of the promised goods or services in the contract; (ii) determination of whether the promised goods or services are performance obligations including whether they are distinct in the context of the contract; (iii) measurement of the transaction price, including the constraint on variable consideration; (iv) allocation of the transaction price to the performance obligations based on estimated selling prices; and (v) recognition of revenue when (or as) the Company satisfies each performance obligation. Performance Obligations A performance obligation is a promise in a contract to transfer a distinct good or service to the customer and is the unit of account in ASC Topic 606. The Company has optional additional items in contracts, which are considered marketing offers and are accounted for as separate contracts when the customer elects such options. Arrangements that include a promise for future commercial product supply and optional research and development services at the customer’s or the Company’s discretion are generally considered as options. The Company assesses if these options provide a material right to the licensee and if so, such material rights are accounted for as separate performance obligations. If the Company is entitled to additional payments when the customer exercises these options, any additional payments are recorded in revenue when the customer obtains control of the goods or services. Transaction Price The Company has both fixed and variable consideration. Non-refundable upfront fees and product supply selling prices are considered fixed, while milestone payments are identified as variable consideration when determining the transaction price. Funding of research and development activities is considered variable until such costs are reimbursed at which point they are considered fixed. The Company allocates the total transaction price to each performance obligation based on the relative estimated standalone selling prices of the promised goods or services for each performance obligation. At the inception of each arrangement that includes milestone payments, the Company evaluates whether the milestones are considered probable of being achieved and estimates the amount to be included in the transaction price using the most likely amount method. If it is probable that a significant revenue reversal would not not not For arrangements that include sales-based royalties, including milestone payments based on the level of sales, and the license is deemed to be the predominant item to which the royalties relate, the Company recognizes revenue at the later of (a) when the related sales occur, or (b) when the performance obligation to which some or all of the royalty has been allocated has been satisfied (or partially satisfied). Allocation of Consideration As part of the accounting for these arrangements, the Company must develop assumptions that require judgment to determine the stand-alone selling price of each performance obligation identified in the contract. Estimated selling prices for license rights and material rights for discounts on manufacturing services are calculated using an income approach model and can include the following key assumptions: the development timeline, sales forecasts, costs of product sales, commercialization expenses, discount rate, the time which the manufacturing services are expected to be performed, and probabilities of technical and regulatory success. For all other performance obligations, the Company uses a cost-plus margin approach. Timing of Recognition Significant management judgment is required to determine the level of effort required under an arrangement and the period over which the Company expects to complete its performance obligations under the arrangement. The Company estimates the performance period or measure of progress at the inception of the arrangement and re-evaluates it each reporting period. This re-evaluation may Cost of Goods Sold Under the Amended Agreements with Grünenthal, the Company sells Zalviso to Grünenthal at predetermined, contractual transfer prices that are less than the direct costs of manufacturing and recognizes indirect costs as period costs where they are in excess of normal capacity and not third Research and Development Expenses Research and development costs are charged to expense when incurred. Research and development expenses include salaries, employee benefits, including stock-based compensation, consultant fees, laboratory supplies, costs associated with clinical trials and manufacturing, including contract research organization fees, other professional services and allocations of corporate costs. The Company reviews and accrues clinical trial expenses based on work performed, which relies on estimates of total costs incurred based on patient enrollment, completion of patient studies and other events. Stock-Based Compensation Compensation expense for all share-based payment awards made to employees and directors, including employee stock options and restricted stock units related to the 2011 2011 2011 The Black-Scholes option pricing model requires inputs such as expected term, expected volatility and risk-free interest rate. These inputs are subjective and generally require significant analysis and judgment to develop. Estimates of expected life during the year ended December 31, 2016, not December 31, 2017, December 31, 2016, January 1, 2017, 2016 09 not Non-Cash Interest Expense on Liability Related to Sale of Future Royalties In September 2015, December 16, 2013, $65.0 $195.0 $61.2 There are a number of factors that could materially affect the amount and timing of royalty payments from Zalviso in Europe, most of which are not not The Company will record non-cash royalty revenues and non-cash interest expense within its Consolidated Statements of Comprehensive Loss over the term of the Royalty Monetization. Comprehensive Loss Comprehensive loss is comprised of net loss and other comprehensive income (loss) and is disclosed in the Consolidated Statements of Comprehensive Loss. For the Company, other comprehensive income (loss) consists of changes in unrealized gains and losses on the Company’s investments. Income Taxes Deferred tax assets and liabilities are measured based on differences between the financial reporting and tax basis of assets and liabilities using enacted rates and laws that are expected to be in effect when the differences are expected to reverse. The Company records a valuation allowance for the full amount of deferred assets, which would otherwise be recorded for tax benefits relating to operating loss and tax credit carryforwards, as realization of such deferred tax assets cannot be determined to be more likely than not. 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, convertible preferred stock, options to purchase common stock, restricted stock subject to repurchase, warrants to purchase convertible preferred stock and warrants to purchase common stock were considered to be common stock equivalents. In periods with a reported net loss, such common stock equivalents are excluded from the calculation of diluted net loss per share of common stock if their effect is antidilutive. For additional information regarding the net loss per share, see Note 14 Recently Adopted Accounting Pronouncement In May 2014, No. 2014 09, Revenue from Contracts with Customers (Topic 606 August 2015 March, April, May December 2016, 606, 606, 606 December 15, 2017, one The Company adopted the new standard effective January 1, 2018 first 2018 not January 1, 2018. no no no In May 2017, 2017 09, Compensation - Stock Compensation (Topic 718 Scope of Modification Accounting 718. not ● The award’s fair value (or calculated value or intrinsic value, if those measurement methods are used), ● The award’s vesting conditions, and ● The award’s classification as an equity or liability instrument. ASU 2017 09 December 15, 2017 not 2017 09 January 1, 2018 not In November 2016, No. 2016 18, Statement of Cash Flows (Topic 230 No. 2016 18 No. 2016 18, not In August 2016, No. 2016 15, Statement of Cash Flows (Topic 230 eight December 15, 2017, 2016 15 January 1, 2018 not Recently Issued Accounting Pronouncements In February 2016, No. 2016 02, Leases (Topic 842 January, July December 2018, July 2018 No. 2018 11, Leases (Topic 842 No. 2018 11, December 15, 2018, January 1, 2019. The Company is substantially complete with its evaluation of the new standard as it relates to its operating lease disclosed in Note 11 may not not may

Note 2 - Investments and Fair V

Note 2 - Investments and Fair Value Measurement	12 Months Ended
	Dec. 31, 2018
Notes to Financial Statements
Investments and Fair Value Measurement Disclosure [Text Block]	2. 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 The table below summarizes the Company’s cash, cash equivalents and investments (in thousands): As of December 31 , 201 8 Amortized Cost Gross Unrealized Gross Unrealized Fair Cash and cash equivalents: Cash $ 2,037 $ — $ — $ 2,037 Money market funds 1,436 — — 1,436 U.S. government agency securities 10,181 — — 10,181 Commercial paper 74,321 — — 74,321 Total cash and cash equivalents 87,975 — — 87,975 Short-term investments: U.S. government agency securities $ 1,497 $ — $ — $ 1,497 Commercial paper 16,243 — — 16,243 Total marketable securities and commercial paper 17,740 — — 17,740 Total cash, cash equivalents and investments $ 105,715 $ — $ — $ 105,715 As of December 31 , 201 7 Amortized Cost Gross Unrealized Gross Unrealized Fair Cash and cash equivalents: Cash $ 29,765 $ — $ — $ 29,765 U.S. government agency securities 23,137 — — 23,137 Total cash and cash equivalents 52,902 — — 52,902 Short-term investments: U.S. government agency securities $ 7,567 $ — $ — $ 7,567 Total marketable securities 7,567 — — 7,567 Total cash, cash equivalents and investments $ 60,469 $ — $ — $ 60,469 None no December 31, 2018 2017. no December 31, 2018 2017. No no December 31, 2018 2017. As of December 31, 2018 2017, one Fair Value Measurement The Company’s financial instruments consist of Level I and II assets and Level III liabilities. Money market funds are highly liquid investments and are actively traded. The pricing information on these investment instruments are readily available and can be independently validated as of the measurement date. This approach results in the classification of these securities as Level 1 third December 31, 2018 December 31, 2017, 2014 1 8 two 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 December 31 , 201 8 Fair Value Level I Level II Level III Assets Money market funds $ 1,436 $ 1,436 $ — $ — U.S. government agency securities 11,678 — 11,678 — Commercial paper 90,564 — 90,564 — Total assets measured at fair value $ 103,678 $ 1,436 $ 102,242 $ — Liabilities Contingent put option liability $ 121 $ — $ — $ 121 Total liabilities measured at fair value $ 121 $ — $ — $ 121 As of December 31 , 201 7 Fair Value Level I Level II Level III Assets U.S. government agency securities $ 30,704 $ — $ 30,704 $ — Total assets measured at fair value $ 30,704 $ — $ 30,704 $ — Liabilities Contingent put option liability $ 207 $ — $ — $ 207 Total liabilities measured at fair value $ 207 $ — $ — $ 207 The following table sets forth a summary of the changes in the fair value of the Company’s Level III financial liabilities for the years ended December 31, 2018 2017 Year Ended 8 Fair value—beginning of period $ 207 Change in fair value of contingent put option associated with Amended Loan Agreement (86 ) Fair value—end of period $ 121 Year Ended 7 Fair value—beginning of period $ 412 Expiration of fair value of PIPE warrants (288 ) Change in fair value of contingent put option associated with Amended Loan Agreement 83 Fair value—end of period $ 207

Note 3 - Inventories

Note 3 - Inventories	12 Months Ended
	Dec. 31, 2018
Notes to Financial Statements
Inventory Disclosure [Text Block]	3. Inventories consist of finished goods, raw materials and work in process and are stated at the lower of cost or market and consist of the following (in thousands): As of December 31, 201 8 201 7 Raw materials $ 694 $ 702 Work-in-process 160 254 Inventories $ 854 $ 956 The Company periodically evaluates the carrying value of inventory on hand for potential excess amount over demand using the same lower of cost or market approach as that used to value the inventory. During the year ended December 31, 2017, $0.4

Note 4 - Property and Equipment

Note 4 - Property and Equipment	12 Months Ended
	Dec. 31, 2018
Notes to Financial Statements
Property, Plant and Equipment Disclosure [Text Block]	4. Property and equipment consist of the following (in thousands): As of December 31, 201 8 201 7 Laboratory equipment $ 3,972 $ 3,920 Leasehold improvements 4,469 4,469 Computer equipment and software 237 241 Construction in process 10,593 9,703 Tooling 1,109 1,109 Furniture and fixtures 47 47 20,427 19,489 Less accumulated depreciation and amortization (8,944 ) (8,438 ) Property and equipment, net $ 11,483 $ 11,051 Depreciation and amortization expense was $0.5 $1.7 $2.1 December 31, 2018, 2017 2016,

Note 5 - Adoption of ASC Topic

Note 5 - Adoption of ASC Topic 606, Revenue From Contracts With Customers	12 Months Ended
	Dec. 31, 2018
Notes to Financial Statements
Revenue from Contract with Customer [Text Block]	5 Adoption of ASC Topic 606, Revenue from Contracts with Customers On January 1, 2018, 606 not January 1, 2018. January 1, 2018, 606, not 605. no January 1, 2018. Revenue Recognition As described in Note 1 December 31, 2018, $3.5 2029. For additional detail on the Company’s accounting policy regarding revenue recognition, refer to Note 1 The following table presents changes in the Company’s contract liabilities for the year ended December 31, 2018: Balance at Beginning of the Period Additions Deductions Balance at the end of the Period (in thousands) Contract liability: Deferred revenue $ 3,825 $ - $ (362 ) $ 3,463 During the year ended December 31, 2018, Year ended December 31 , 2018 Amounts included in contract liabilities at the beginning of the period: Performance obligations satisfied – Amended Agreements $ 362 New activities in the period from performance obligations satisfied: Performance obligations satisfied – Amended Agreements 566 Total revenue from performance obligations satisfied 928 Royalty revenue 385 Contract and other 838 Total revenue $ 2,151

Note 6 - U.S. Department of Def

Note 6 - U.S. Department of Defense Funding	12 Months Ended
	Dec. 31, 2018
Notes to Financial Statements
Long-term Contracts or Programs Disclosure [Text Block]	6 . U.S. Department of Defense Funding On May 11, 2015, $17.0 30 May 11, 2015. March 2, 2016, SAP302 SAP303 four November 10, 2016 March 9, 2017, SAP302 SAP303 March 9, 2017, 11 February 28, 2018 December 31, 2017, February 28, 2018 February 28, 2018, $0.5 twelve February 28, 2019. Revenue is recognized based on expenses incurred by the Company in conducting research and development activities, including overhead, as set forth in the agreement. Revenue attributable to the work performed under the DoD Contract, recorded as Contract and other revenue in the Consolidated Statements of Comprehensive Loss, was $0.8 $0.9 $10.9 December 31, 2018, 2017 2016,

Note 7 - Collaboration Agreemen

Note 7 - Collaboration Agreement	12 Months Ended
	Dec. 31, 2018
Notes to Financial Statements
Collaborative Arrangement Disclosure [Text Block]	7. As described in Note 1 January 1, 2018, 606, Revenue from Contracts with Customers $5.5 $171.5 $166.0 $0.7 $3.7 2016. Amended License Agreement Under the terms of the Amended 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 $0.7 fourth 2014 September 2015, 28 April 2016, first The Company received an upfront non-refundable cash payment of $30.0 December 2013, $5.0 third 2014, $15.0 September 2015. $194.5 $28.5 $166.0 9 Amended MSA Under the terms of the Amended 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 December 16, 2013 December 15, 2018, 100% 80% not third third Unless earlier terminated, the Amended 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 Amended License Agreement. The Amended MSA is subject to earlier termination in connection with certain termination events in the Amended 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. Prior to the adoption of ASC Topic 606 January 1, 2018, 605. 1, not not 605. The Company identified four 1 2 3 4 At the time the Amended Agreements were executed, with the exception of the intellectual property license, these obligations remained partially unsatisfied. Additionally, the Company identified the following three 1 2 3 The Company determined that the performance obligations outlined above are considered distinct and thus should be treated as separate units of accounting. The Company’s management determined that the license under the original License Agreement was distinct and represented a separate unit of accounting because it is considered functional intellectual property and the rights conveyed permitted 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 third none The Company believes that none third none third The Company’s management determined the standalone 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 standalone 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, the 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 estimated cost of manufacturing, and the anticipated volume of Grünenthal’s orders over the course of the agreement, to which the discount would apply. For the Zalviso demonstration devices and the obligation to manufacture and deliver Product, the Company’s management estimated the selling price based on the binding volume of such devices and Products, the estimated cost of manufacturing, and the market level of contract manufacturing margin. The standalone selling price of the license, research and development and committee participation services and the discount on manufacturing services were updated at the time the Amended Agreements were executed for purposes of allocating the amended arrangement consideration. The original Agreements included two $20.0 July 2014, first two $5.0 September 2015, second two $15.0 606 January 1, 2018, $20.0 December 31, 2018, $1.0 The Amended Agreements entitle the Company to receive additional payments upon the achievement of certain development milestones which relate to post approval product enhancements, expanded market opportunities and manufacturing efficiencies for Zalviso and require future research, development and regulatory activities. These payments are excluded from the transaction price as they are considered payments for optional additional services that Grünenthal may 606 not The Amended Agreements also include milestone payments related to specified net sales targets, totaling $166.0 606 The Company recognizes revenue from license rights when the customer can use and benefit from the license rights. The Company recognizes revenue from its services performance obligations over time using a cost-to-cost input method which best represents the incremental benefit that the customer receives as control is transferred. Below is a summary of revenue recognized under the Amended Agreements during the years ended December 31, 2018, 2017 2016 Years Ended December 31, 201 8 2017 201 6 Product sales $ 825 $ 6,673 $ 5,742 Joint steering committee, research and development services and demonstration devices 103 269 688 Non-cash royalty revenue related to Royalty Monetization (See Note 9) 289 151 7 Royalty revenue 96 50 3 Total $ 1,313 $ 7,143 $ 6,440 As of December 31, 2018, $0.3 $3.2

Note 8 - Long-term Debt

Note 8 - Long-term Debt	12 Months Ended
	Dec. 31, 2018
Notes to Financial Statements
Long-term Debt [Text Block]	8 . Long-Term Debt Amended Loan and Security Agreement On December 16, 2013, $40.0 three 2013 June 29, 2011. first $15.0 December 16, 2013, second $10.0 June 16, 2014. $8.6 first $24.9 December 31, 2014. 176,730 $6.79 On September 24, 2014, No. 1 No. 1 third $15.0 March 15, 2015 August 1, 2015, not August 1, 2015 not third On September 18, 2015, No. 2, No. 2, No. 2 October 1, 2015 March 31, 2016, September 30, 2016 third 2015 September 30, 2016. October 1, 2017. No. 2, 176,730 $6.79 $3.88 On September 30, 2016, No. 3 No. 3 October 1, 2016 April 1, 2017. No. 3, 176,730 $3.88 $3.07 On March 2, 2017, first $20.5 March 2, 2017, first $1.7 October 1, 2017. 9.55% 3.50%, 9.55%. October 1, 2017 March 1, 2020. 6.5% If the Company prepays the loans under the Amended Loan Agreement prior to the maturity date, it will pay Hercules a prepayment charge, based on a percentage of the then outstanding principal balance, equal to 2% March 2, 2018, March 2, 2019, 1% March 2, 2019. The Amended Loan Agreement includes customary affirmative and restrictive covenants, but does not 5% may may 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. This option is considered a contingent put option liability, as the holder of the loan has the ability to 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 Original Loan Agreement entered into on December 16, 2013 $32 December 31, 2018 2017, $0.1 $0.2 two The Company performed an analysis of Amendments No. 2 No. 3 No. 2 No. 3 The accrued balance due under the Amended Loan Agreement was $12.0 $19.1 December 31, 2018 2017, $2.2 $3.3 $2.8 December 31, 2018, 2017 2016, Future Payments on Long-Term Debt The following table summarizes the outstanding future payments associated with the Company’s long-term debt as of December 31, 2018 2019 $ 9,437 2020 3,701 Total payments 13,138 Less amount representing interest (872 ) Notes payable, gross 12,266 Unamortized portion of final payment (229 ) Unamortized discount on notes payable (46 ) Long-term debt 11,991 Less current portion of notes payable, including unamortized discount (8,611 ) Long-term debt, current portion $ 3,380

Note 9 - Liability Related to S

Note 9 - Liability Related to Sale of Future Royalties	12 Months Ended
	Dec. 31, 2018
Notes to Financial Statements
Liability Related To Sale Of Future Royalties Disclosure [Text Block]	9 . Liability Related to Sale of Future Royalties On September 18, 2015, $65.0 $195.0 75% 80% first four $35.6 80% $44.5 25% 20% first four 100% $43.5 $15.0 The Company and ARPI LLC continue to retain certain duties and obligations under the Amended License Agreement. These include the collection of the royalty and milestones amounts due and enforcement of related provisions under the Amended License Agreement, among others. In addition, the Company must prepare a quarterly distribution report relating to the Amended License Agreement, containing among other items, the amount of royalty and milestone payments received, reimbursable expenses and set-offs. The Company and ARPI LLC must also provide PDL with notice of certain communications, events or actions with respect to the Amended License Agreement and infringement of any underlying intellectual property. The Company has significant continuing involvement in the Royalty Monetization primarily due to an obligation to act as the intermediary for the supply of Zalviso to Grünenthal. Under the relevant accounting guidance, because of its significant continuing involvement, the Royalty Monetization has been accounted for as a liability that will be amortized using the effective interest method over the life of the arrangement. In order to determine the amortization of the liability, the Company is required to estimate the total amount of future royalty and milestone payments to be received by ARPI LLC and paid to PDL, up to a capped amount of $195.0 $61.2 The Company periodically assesses the expected royalty and milestone payments using a combination of historical results, internal projections and forecasts from external sources. To the extent such payments are greater or less than the Company’s initial estimates or the timing of such payments is materially different than its original estimates, the Company will prospectively adjust the amortization of the liability and the effective interest rate. From inception through December 31, 2018, 13.0%; 7.0% December 31, 2018, 2017 2016, 11.6%, 13.6%, 13.7%, There are a number of factors that could materially affect the amount and timing of royalty payments from Zalviso in Europe, most of which are not not The following table shows the activity within the liability account during the year ended December 31, 2018 ( Year ended 8 Period from inception to 8 Liability related to sale of future royalties — beginning balance $ 83,588 $ — Proceeds from sale of future royalties — 61,184 Non-cash royalty revenue (250 ) (377 ) Non-cash interest expense recognized 10,341 32,872 Liability related to sale of future royalties as of December 31, 2018 93,679 93,679 Less: current portion (392 ) (392 ) Liability related to sale of future royalties — net of current portion $ 93,287 $ 93,287 As royalties are remitted to PDL from ARPI LLC, as described in Note 1

Note 10 - Warrants

Note 10 - Warrants	12 Months Ended
	Dec. 31, 2018
Notes to Financial Statements
Warrants Disclosure [Text Block]	10 . Warrants Amended and Restated Loan Agreement Warrants In connection with the Original Loan Agreement, executed in December 2013, 176,730 $6.79 No. 2 $6.79 $3.88 No. 3 $3.88 $3.07 may five $1.1 $6.79, $9.67, five 1.55%, 71% 0% $0.1 September 2015 $45.0 September 2016 In December 2018, 176,730 2012 In connection with the Private Placement, completed in June 2012, 2,630,103 $3.40 May 29, 2012, six five 50% may 2 Upon execution of the Purchase Agreement, the fair value of the PIPE warrants was estimated to be $5.8 December 31, 2017 2016, $0.3 $0.6 During the year ended December 31, 2017, 512,456

Note 11 - Commitments and Conti

Note 11 - Commitments and Contingencies	12 Months Ended
	Dec. 31, 2018
Notes to Financial Statements
Commitments and Contingencies Disclosure [Text Block]	1 1 . Commitments and Contingencies Operating Leases In December 2011, 13,787 301 April 2012. December 2011, In May 2014, twenty 20 twenty-two 22 January 31, 2018, 12,106 351 42 August 1, 2014 January 31, 2018. On October 2, 2015, 11,871 26 December 1, 2015. first two $2.05 $25.0 $0.3 December 31, 2018 2017, On June 14, 2017, second 25,893 301 351 seventy-two 72 February 1, 2018 January 31, 2024, On January 2, 2019, 12,106 February 16, 2019 January 31, 2024. $48,000 Pursuant to the Lease Amendment, the Company will pay on a monthly basis annual rent of approximately $1.2 12 February 1 st first two not Rent expense was $1.1 $0.6 $0.3 December 31, 2018, 2017 2016, Future minimum payments under the Lease as of December 31, 2018, Year Ending December 31: 2019 $ 1,230 2020 1,268 2021 1,305 2022 1,345 2023 1,386 Thereafter 116 Total minimum payments $ 6,650 Litigation From time to time the Company may not

Note 12 - Stockholders' Equity

Note 12 - Stockholders' Equity	12 Months Ended
	Dec. 31, 2018
Notes to Financial Statements
Stockholders' Equity Note Disclosure [Text Block]	1 2 . Stockholders’ Equity Common Stock 2018 On November 14, 2018, 12,698,412 $3.15 November 12, 2018, 1,904,761 $3.15 14,603,173 $46.0 $43.1 On July 16, 2018, 7,272,727 $2.75 August 7, 2018, 1,090,909 $2.75 8,363,636 $23.0 $21.7 201 6 ATM Agreement On June 21, 2016, SM 2016 may $40.0 December 31, 2018, 4.4 $16.8 $0.4 December 31, 2017, 5.4 2016 $15.7 $0.5 Stock Plans 2006 In August 2006, 2006 342 February 2008, 375 2006 November 2009, 1.4 2006 2006 10% not 110% no may 2006 2011 In January 2011, 2011 2011 2006 2011 February 10, 2011. February 10, 2011, no may 2006 2006 2006 52 2006 2011 The initial aggregate number of shares of the Company’s common stock that may 2011 1.9 52 2006 1.8 2011 January 1st January 1, 2012 January 1, 2020, 4% December 31 not 10 2011 four 10 not 2011 Additionally, in January 2011, 2011 Initially, 250 January 1st January 1, 2012 January 1, 2020, 1 2% December 31 2 not As of December 31, 2018, 858,889 December 31, 2018, 182,360 2018, 2017 2016 $1.51, $2.59 $2.98

Note 13 - Stock-based Compensat

Note 13 - Stock-based Compensation	12 Months Ended
	Dec. 31, 2018
Notes to Financial Statements
Disclosure of Compensation Related Costs, Share-based Payments [Text Block]	1 3 . Stock-Based Compensation The Company recorded total stock-based compensation expense for stock options, stock awards and the ESPP as follows December 31, 8 December 31, 7 December 31, 6 Cost of goods sold $ 358 $ 324 $ 302 Research and development 1,970 1,901 2,308 General and administrative 2,840 2,069 1,869 Total $ 5,168 $ 4,294 $ 4,479 The following table summarizes option activity under the 2011 2006 Number Weighted- Weighted- Aggregate (in thousands) December 31, 2017 8,455,098 $ 4.25 Granted 3,553,713 2.28 Forfeited (217,816 ) 2.87 Expired (232,905 ) 6.36 Exercised (135,385 ) 2.96 December 31, 2018 11,422,705 $ 3.64 7.1 $ 659 Vested and exercisable options—December 31, 2018 6,468,788 $ 4.44 5.8 $ 46 Vested and expected to vest—December 31, 2018 11,422,705 $ 3.64 7.1 $ 659 As of December 31, 2018, 1,217,341 2011 January 2019, 3,150,317 2011 Additional information regarding the Company’s stock options outstanding and vested and exercisable as of December 31, 2018 Options Outstanding Options Vested and Exercisable Exercise Prices Number of Weighted-Average Weighted-Average Shares Subject Weighted-Average $1.20 - $2.00 1,856,170 9.0 $ 2.00 6,900 $ 1.20 $2.225 - $3.35 5,406,951 7.8 $ 2.82 2,698,203 $ 2.82 $3.37 - $5.31 2,855,022 5.2 $ 4.13 2,459,123 $ 4.19 $5.45 - $8.18 688,562 5.0 $ 6.47 688,562 $ 6.47 $10.22 - $10.55 616,000 5.1 $ 10.34 616,000 $ 10.34 11,422,705 7.1 $ 3.64 6,468,788 $ 4.44 The weighted average grant-date fair value of options granted during the years ended December 31, 2018, 2017 2016 $1.62, $1.91 $2.24 December 31, 2018, $7.5 2.4 December 31, 2018, 2017 2016 $4.9 $3.5 $3.9 December 31, 2018 2017 $0.2 $40 no December 31, 2016. The Company used the following assumptions to calculate the fair value of each employee stock option: Year Ended December 31, 201 8 201 7 201 6 Expected term (in years) 5.89 5.70 5.25 - 6.25 Risk-free interest rate 2.5% - 3.1% 1.82% - 2.09% 1.24% - 1.47% Expected volatility 83% 73% 80% Expected dividend rate 0% 0% 0%

Note 14 - Net Loss Per Share of

Note 14 - Net Loss Per Share of Common Stock	12 Months Ended
	Dec. 31, 2018
Notes to Financial Statements
Earnings Per Share [Text Block]	14. 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. The PIPE warrants expired during the year ended December 31, 2017. December 31, 2016, December 31, 2016. 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: Year Ended December 31, 201 8 201 7 201 6 ESPP and stock options to purchase common stock 11,797,960 8,767,783 6,395,879 Convertible debt into common stock — — 553,763 Common stock warrants — 176,730 692,611

Note 15 - Accrued Liabilities

Note 15 - Accrued Liabilities	12 Months Ended
	Dec. 31, 2018
Notes to Financial Statements
Accounts Payable and Accrued Liabilities Disclosure [Text Block]	15. Accrued liabilities consist of the following (in thousands): December 31, 201 8 201 7 Accrued compensation and employee benefits $ 3,611 $ 2,190 Inventory and other contract manufacturing accruals 234 511 Other accrued liabilities 695 842 Total accrued liabilities $ 4,540 $ 3,543

Note 16 - 401(k) Plan

Note 16 - 401(k) Plan	12 Months Ended
	Dec. 31, 2018
Notes to Financial Statements
Pension and Other Postretirement Benefits Disclosure [Text Block]	16. 401 The Company sponsors a 401 401 401 4% $0.3 December 31, 2018, 2017 2016.

Note 17 - Income Taxes

Note 17 - Income Taxes	12 Months Ended
	Dec. 31, 2018
Notes to Financial Statements
Income Tax Disclosure [Text Block]	17 . Income Taxes The Company recorded a provision for income taxes of $2.0 December 31, 2018, $0.7 December 31, 2017, $34.0 December 31, 2016. The provision (benefit) for income taxes consisted of the following (in thousands): December 31, 8 December 31, 7 Current: Federal $ — $ (702 ) State 2 1 Total Current 2 (701 ) Deferred: Federal — — State — — Total Deferred — — Provision (benefit) for income taxes $ 2 $ (701 ) Net deferred tax assets as of December 31, 2018 2017 December 31, 8 December 31, 7 Deferred tax assets: Accruals and other $ 3,263 $ 2,717 Research credits 7,275 6,530 Net operating loss carryforward 39,082 31,064 Section 59(e) R&D expenditures 10,387 12,156 Deferred revenue 20,689 18,384 Total deferred tax assets 80,696 70,851 Valuation allowance (80,696 ) (70,851 ) Net deferred tax assets $ — $ — Reconciliations of the statutory federal income tax to the Company’s effective tax during the years ended December 31, 2018, 2017 2016 Year Ended December 31, 201 8 201 7 201 6 Tax at statutory federal rate $ (9,901 ) $ (17,751 ) $ (14,685 ) State tax—net of federal benefit (792 ) 350 (73 ) PIPE warrant liability (18 ) (70 ) (260 ) General business credits (500 ) (316 ) (360 ) Stock options 1,048 42 1,115 Other 313 51 33 Change in valuation allowance 9,852 (17,110 ) 14,196 Tax reform – tax rate change — 34,103 — Provision for income taxes $ 2 $ (701 ) $ (34 ) ASC 740 not.” $9.9 $17.1 $14.2 December 31, 2018, 2017 2016, As of December 31, 2018, $153.2 $114.9 January 1, 2018 2029. $38.3 2018 80% December 31, 2018, $97.2 2028. As of December 31, 2017, $0.7 December 22, 2017, $0.4 $0.3 As of December 31, 2018, $6.5 2026. December 31, 2018, $4.0 The Company adopted ASU 2016 09 December 31, 2017. $2.9 $2.0 December 31, 2017. Under Section 382 1986, 50% three may December 31, 2013, two first 2006 $1.4 $26,000 second July 2013 not On December 22, 2017, 2017 35% 21% December 31, 2017, one December 31, 2017. December 31, 2017 $0.7 fourth 2017, $0.7 No not Uncertain Tax Positions A reconciliation of the beginning and ending balances of the unrecognized tax benefits during the years ended December 31, 2018, 2017 2016 Year Ended December 31, 2018 2017 2016 Unrecognized benefit—beginning of period $ 2,365 $ 2,162 $ 1,939 Gross increases—prior period tax positions 57 — — Gross increases—current period tax positions 213 203 223 Unrecognized benefit—end of period $ 2,635 $ 2,365 $ 2,162 The entire amount of the unrecognized tax benefits would not There were no December 31, 2018, 2017 2016. 2005 2018 not not 12

Note 18 - Subsequent Event

Note 18 - Subsequent Event	12 Months Ended
	Dec. 31, 2018
Notes to Financial Statements
Subsequent Events [Text Block]	18. On January 2, 2019, 12,106 February 16, 2019 January 31, 2024. $48,000

Note 19 - Unaudited Quarterly F

Note 19 - Unaudited Quarterly Financial Data	12 Months Ended
	Dec. 31, 2018
Notes to Financial Statements
Quarterly Financial Information [Text Block]	1 9 . Unaudited Quarterly Financial Data The following table sets forth certain unaudited quarterly financial data for the eight December 31, 2018. not 201 8 2017 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Revenues $ 343 $ 818 $ 377 $ 613 $ 3,109 $ 2,659 $ 1,487 $ 740 Operating costs and expenses $ 8,612 $ 7,971 $ 9,705 $ 11,590 $ 15,182 $ 12,600 $ 10,348 $ 8,547 Net loss $ (11,592 ) $ (10,541 ) $ (12,458 ) $ (12,558 ) $ (15,551 ) $ (13,059 ) $ (13,013 ) $ (9,885 ) Net loss per share (basic and diluted) $ (0.23 ) $ (0.20 ) $ (0.21 ) $ (0.18 ) $ (0.34 ) $ (0.29 ) $ (0.28 ) $ (0.20 )

Significant Accounting Policies

Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2018
Accounting Policies [Abstract]
Business Description of Entity [Policy Text Block]	The Company AcelRx Pharmaceuticals, Inc., or the Company or AcelRx, was incorporated in Delaware on July 13, 2005 January 2006, AcelRx is a specialty pharmaceutical company focused on the development and commercialization of innovative therapies for use in medically supervised settings. DSUVIA (known as DZUVEO in Europe) and Zalviso, are November 2, 2018, June 2018, first 2019. not may one not DSUVIA DSUVIA, known as DZUVEO in Europe, approved by the FDA in November 2018, June 2018. DSUVIA was approved with a Risk Evaluation and Mitigation Strategy, or REMS, which restricts distribution to certified medically supervised healthcare settings in order to prevent respiratory depression resulting from accidental exposure. DSUVIA will only be distributed to facilities certified in the DSUVIA REMS program following attestation by an authorized representative to comply with appropriate dispensing and use restrictions of DSUVIA. To become certified, a healthcare setting will need to train their healthcare professionals on the proper use of DSUVIA and have the ability to manage respiratory depression. DSUVIA will not Zalviso Zalviso delivers 15 September 2013 July 25, 2014. IAP312, IAP312 August 2017, three 3 On December 16, 2013, July 17, 2015 September 20, 2016, September 2015, December 16, 2013, July 22, 2015, July 17, 2015. The Company has incurred recurring operating losses and negative cash flows from operating activities since inception. Although Zalviso has been approved for sale in Europe, on September 18, 2015, November 2018 first 2019. Except as the context otherwise requires, when we refer to "we," "our," "us," the "Company" or "AcelRx" in this document, we mean AcelRx Pharmaceuticals, Inc., and its consolidated subsidiary. “DSUVIA” and “DZUVEO” are trademarks, and “ACELRX” and “Zalviso” are registered trademarks, all owned by AcelRx Pharmaceuticals, Inc. This report also contains trademarks and trade names that are the property of their respective owners.
Basis of Accounting, Policy [Policy Text Block]	Basis of Presentation The preparation of financial statements in conformity with generally accepted accounting principles requires management to make estimates and assumptions that affect the amounts reported in the Consolidated Financial Statements and the accompanying notes. Actual results could differ from those estimates.
Reclassification, Policy [Policy Text Block]	Reclassifications Certain prior year amounts in the Consolidated Financial Statements have been reclassified to conform to the current year's presentation. In particular, the amount reported in the Consolidated Statements of Cash Flows as “Noncash Investing and Financing Activities – Purchases of property and equipment in Accrued liabilities” has been reclassified to “Noncash Investing and Financing Activities – Purchases of property and equipment in Accounts payable” for the year ended December 31, 2017, December 31, 2016.
Consolidation, Policy [Policy Text Block]	Principles of Consolidation The Consolidated Financial Statements include the accounts of the Company and its wholly owned subsidiary, ARPI LLC, which was formed in September 2015 9
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 Consolidated 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
Cash, Cash Equivalents, and Marketable Securities [Policy Text Block]	Cash, Cash Equivalents and Marketable Securities The Company considers all highly liquid investments with an original maturity (at date of purchase) of three All marketable securities are classified as available-for-sale and consist of U.S. government sponsored enterprise debt securities and commercial paper. These securities are carried at estimated fair value, which is based on quoted market prices or observable market inputs of almost identical assets, with unrealized gains and losses included in accumulated other comprehensive income (loss). The amortized cost of securities is adjusted for amortization of premiums and accretion of discounts to maturity. Such amortization and accretion is included in interest income or expense. The cost of securities sold is based on specific identification. The Company’s investments are subject to a periodic impairment review for other-than-temporary declines in fair value. The Company’s review includes the consideration of the cause of the impairment including the creditworthiness of the security issuers, the number of securities in an unrealized loss position, the severity and duration of the unrealized losses and the Company’s intent and ability to hold the investment for a period of time sufficient to allow for any anticipated recovery in the market value. When the Company determines that the decline in fair value of an investment is below its accounting basis and this decline is other-than-temporary, it reduces the carrying value of the security it holds and records a loss in the amount of such decline.
Fair Value Measurement, Policy [Policy Text Block]	Fair Value of Financial Instruments The Company measures and reports its cash equivalents, investments and financial liabilities at fair value. Fair value is defined as the exchange price that would be received for an asset or an exit price paid to transfer a liability in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. Valuation techniques used to measure fair value must maximize the use of observable inputs and minimize the use of unobservable inputs. The fair value hierarchy defines a three Level I—Unadjusted quoted prices in active markets for identical assets or liabilities; Level II—Inputs other than quoted prices included within Level I that are observable, unadjusted quoted prices in markets that are not Level III—Unobservable inputs that are supported by little or no The categorization of a financial instrument within the valuation hierarchy is based upon the lowest level of input that is significant to the fair value measurement.
Segment Reporting, Policy [Policy Text Block]	Segment Information The Company operates in a single segment, the development and commercialization of product candidates for the treatment of pain. The Company’s contract revenue relates to sales in the United States. The Company’s collaboration revenue relates to the Amended License Agreement with Grünenthal to commercialize Zalviso in the countries of the European Union, Switzerland, Liechtenstein, Iceland, Norway and Australia.
Concentration Risk, Credit Risk, Policy [Policy Text Block]	Concentration of Risk The Company invests cash that is currently not The Company relies on a single third third To date, the Company has had only two two 100% December 31, 2018, 2017 2016. 100% 79% December 31, 2018, 2017, 71% December 31, 2016. The Company has not December 31, 2018
Receivables, Policy [Policy Text Block]	Accounts Receivable, Net The Company has receivables from its collaboration partner and the U.S. Department of Defense, or DoD. To date, the Company has not
Inventory, Policy [Policy Text Block]	Inventories Inventories are valued at the lower of cost and net realizable value. Cost is determined using the first first third The Company's policy is to write down inventory that has become obsolete, inventory that has a cost basis in excess of its expected net realizable value and inventory in excess of expected requirements. The Company periodically evaluates the carrying value of inventory on hand for potential excess amount over demand using the same lower of cost or market approach as that used to value the inventory. Because the predetermined, contractual transfer prices the Company is receiving from Grünenthal are less than the direct costs of manufacturing, all Zalviso inventories are carried at net realizable value.
Property, Plant and Equipment, Policy [Policy Text Block]	Property and Equipment Property and equipment are stated at cost less accumulated depreciation and amortization. Depreciation is calculated using the straight-line method over the estimated useful lives of the assets, generally three five not
Impairment or Disposal of Long-Lived Assets, Policy [Policy Text Block]	Impairment of Long-Lived Assets The Company periodically assesses the impairment of long-lived assets and, if indicators of asset impairment exist, the Company assesses the recoverability of the affected long-lived assets by determining whether the carrying value of such assets can be recovered through an analysis of the undiscounted future expected operating cash flows. If impairment is indicated, the Company records the amount of such impairment for the excess of the carrying value of the asset over its estimated fair value. For example, if the Company is not may no September 30, 2015, $0.5 December 31, 2015, December 31, 2018, not
Cash and Cash Equivalents, Restricted Cash and Cash Equivalents, Policy [Policy Text Block]	Restricted Cash Under the Company’s facility lease and corporate credit card agreements, the Company is required to maintain letters of credit as security for performance under these agreements. The letters of credit are secured by certificates of deposit in amounts equal to the letters of credit, which are classified as restricted cash on the Consolidated Balance Sheets.
Debt, Policy [Policy Text Block]	Debt Issuance Costs Debt issuance costs, which are included in long-term debt, net of current portion, are amortized as interest expense over the contractual terms of the related credit facilities.
Contingent Put Option, Policy [Policy Text Block]	Contingent put option The contingent put option associated with the Company’s loan and security agreement with Hercules Technology II, L.P. and Hercules Technology Growth Capital, Inc., collectively referred to as the Lenders, is recorded as a liability. Changes in the fair value of the contingent put option are recognized as interest income and other income, net in the Consolidated Statements of Comprehensive Loss. For additional information regarding the contingent put option, see Note 8
Warrants, Policy [Policy Text Block]	Warrants Warrants issued in connection with the Company’s Private Placement, completed in June 2012, 10 December 31, 2018,
Revenue Recognition, Policy [Policy Text Block]	Revenue Recognition Beginning January 1, 2018, 606, Revenue from Contracts with Customers The Company generates revenue from collaboration agreements. These agreements typically include payments for upfront signing or license fees, cost reimbursements for development and manufacturing services, milestone payments, product sales, and royalties on licensee’s future product sales. The Company has entered into award contracts with U.S. Department of Defense, or the DoD, to support the development of DSUVIA. These contracts provide for the reimbursement of qualified expenses for research and development activities. Revenue under these arrangements is recognized when the related qualified research expenses are incurred. The Company is entitled to reimbursement of overhead costs associated with the study costs under the DoD arrangements. The Company estimates this overhead rate by utilizing forecasted expenditures. Final reimbursable overhead expenses are dependent on direct labor and direct reimbursable expenses throughout the life of each contract, which may In determining the appropriate amount of revenue to be recognized as it fulfills its obligations under its agreements, the Company performs the following steps: (i) identification of the promised goods or services in the contract; (ii) determination of whether the promised goods or services are performance obligations including whether they are distinct in the context of the contract; (iii) measurement of the transaction price, including the constraint on variable consideration; (iv) allocation of the transaction price to the performance obligations based on estimated selling prices; and (v) recognition of revenue when (or as) the Company satisfies each performance obligation. Performance Obligations A performance obligation is a promise in a contract to transfer a distinct good or service to the customer and is the unit of account in ASC Topic 606. The Company has optional additional items in contracts, which are considered marketing offers and are accounted for as separate contracts when the customer elects such options. Arrangements that include a promise for future commercial product supply and optional research and development services at the customer’s or the Company’s discretion are generally considered as options. The Company assesses if these options provide a material right to the licensee and if so, such material rights are accounted for as separate performance obligations. If the Company is entitled to additional payments when the customer exercises these options, any additional payments are recorded in revenue when the customer obtains control of the goods or services. Transaction Price The Company has both fixed and variable consideration. Non-refundable upfront fees and product supply selling prices are considered fixed, while milestone payments are identified as variable consideration when determining the transaction price. Funding of research and development activities is considered variable until such costs are reimbursed at which point they are considered fixed. The Company allocates the total transaction price to each performance obligation based on the relative estimated standalone selling prices of the promised goods or services for each performance obligation. At the inception of each arrangement that includes milestone payments, the Company evaluates whether the milestones are considered probable of being achieved and estimates the amount to be included in the transaction price using the most likely amount method. If it is probable that a significant revenue reversal would not not not For arrangements that include sales-based royalties, including milestone payments based on the level of sales, and the license is deemed to be the predominant item to which the royalties relate, the Company recognizes revenue at the later of (a) when the related sales occur, or (b) when the performance obligation to which some or all of the royalty has been allocated has been satisfied (or partially satisfied). Allocation of Consideration As part of the accounting for these arrangements, the Company must develop assumptions that require judgment to determine the stand-alone selling price of each performance obligation identified in the contract. Estimated selling prices for license rights and material rights for discounts on manufacturing services are calculated using an income approach model and can include the following key assumptions: the development timeline, sales forecasts, costs of product sales, commercialization expenses, discount rate, the time which the manufacturing services are expected to be performed, and probabilities of technical and regulatory success. For all other performance obligations, the Company uses a cost-plus margin approach. Timing of Recognition Significant management judgment is required to determine the level of effort required under an arrangement and the period over which the Company expects to complete its performance obligations under the arrangement. The Company estimates the performance period or measure of progress at the inception of the arrangement and re-evaluates it each reporting period. This re-evaluation may
Cost of Sales, Policy [Policy Text Block]	Cost of Goods Sold Under the Amended Agreements with Grünenthal, the Company sells Zalviso to Grünenthal at predetermined, contractual transfer prices that are less than the direct costs of manufacturing and recognizes indirect costs as period costs where they are in excess of normal capacity and not third
Research and Development Expense, Policy [Policy Text Block]	Research and Development Expenses Research and development costs are charged to expense when incurred. Research and development expenses include salaries, employee benefits, including stock-based compensation, consultant fees, laboratory supplies, costs associated with clinical trials and manufacturing, including contract research organization fees, other professional services and allocations of corporate costs. The Company reviews and accrues clinical trial expenses based on work performed, which relies on estimates of total costs incurred based on patient enrollment, completion of patient studies and other events.
Share-based Compensation, Option and Incentive Plans, Director Policy [Policy Text Block]	Stock-Based Compensation Compensation expense for all share-based payment awards made to employees and directors, including employee stock options and restricted stock units related to the 2011 2011 2011 The Black-Scholes option pricing model requires inputs such as expected term, expected volatility and risk-free interest rate. These inputs are subjective and generally require significant analysis and judgment to develop. Estimates of expected life during the year ended December 31, 2016, not December 31, 2017, December 31, 2016, January 1, 2017, 2016 09 not
Interest Expense, Policy [Policy Text Block]	Non-Cash Interest Expense on Liability Related to Sale of Future Royalties In September 2015, December 16, 2013, $65.0 $195.0 $61.2 There are a number of factors that could materially affect the amount and timing of royalty payments from Zalviso in Europe, most of which are not not The Company will record non-cash royalty revenues and non-cash interest expense within its Consolidated Statements of Comprehensive Loss over the term of the Royalty Monetization.
Comprehensive Income, Policy [Policy Text Block]	Comprehensive Loss Comprehensive loss is comprised of net loss and other comprehensive income (loss) and is disclosed in the Consolidated Statements of Comprehensive Loss. For the Company, other comprehensive income (loss) consists of changes in unrealized gains and losses on the Company’s investments.
Income Tax, Policy [Policy Text Block]	Income Taxes Deferred tax assets and liabilities are measured based on differences between the financial reporting and tax basis of assets and liabilities using enacted rates and laws that are expected to be in effect when the differences are expected to reverse. The Company records a valuation allowance for the full amount of deferred assets, which would otherwise be recorded for tax benefits relating to operating loss and tax credit carryforwards, as realization of such deferred tax assets cannot be determined to be more likely than not.
Earnings Per Share, Policy [Policy Text Block]	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, convertible preferred stock, options to purchase common stock, restricted stock subject to repurchase, warrants to purchase convertible preferred stock and warrants to purchase common stock were considered to be common stock equivalents. In periods with a reported net loss, such common stock equivalents are excluded from the calculation of diluted net loss per share of common stock if their effect is antidilutive. For additional information regarding the net loss per share, see Note 14
New Accounting Pronouncements, Policy [Policy Text Block]	Recently Adopted Accounting Pronouncement In May 2014, No. 2014 09, Revenue from Contracts with Customers (Topic 606 August 2015 March, April, May December 2016, 606, 606, 606 December 15, 2017, one The Company adopted the new standard effective January 1, 2018 first 2018 not January 1, 2018. no no no In May 2017, 2017 09, Compensation - Stock Compensation (Topic 718 Scope of Modification Accounting 718. not ● The award’s fair value (or calculated value or intrinsic value, if those measurement methods are used), ● The award’s vesting conditions, and ● The award’s classification as an equity or liability instrument. ASU 2017 09 December 15, 2017 not 2017 09 January 1, 2018 not In November 2016, No. 2016 18, Statement of Cash Flows (Topic 230 No. 2016 18 No. 2016 18, not In August 2016, No. 2016 15, Statement of Cash Flows (Topic 230 eight December 15, 2017, 2016 15 January 1, 2018 not Recently Issued Accounting Pronouncements In February 2016, No. 2016 02, Leases (Topic 842 January, July December 2018, July 2018 No. 2018 11, Leases (Topic 842 No. 2018 11, December 15, 2018, January 1, 2019. The Company is substantially complete with its evaluation of the new standard as it relates to its operating lease disclosed in Note 11 may not not may

Reconciliation of Cash, Cash _2

Reconciliation of Cash, Cash Equivalents, and Restricted Cash (Tables)	12 Months Ended
	Dec. 31, 2018
Notes Tables
Schedule of Cash and Cash Equivalents [Table Text Block]	Year Ended December 31, 2018 2017 2016 CASH AND CASH EQUIVALENTS 87,975 52,902 80,310 RESTRICTED CASH 178 178 178 CASH, CASH EQUIVALENTS AND RESTRICTED CASH SHOWN IN STATEMENT OF CASH FLOWS $ 88,153 $ 53,080 $ 80,488

Note 2 - Investments and Fair_2

Note 2 - Investments and Fair Value Measurement (Tables)	12 Months Ended
	Dec. 31, 2018
Notes Tables
Cash, Cash Equivalents and Investments [Table Text Block]	As of December 31 , 201 8 Amortized Cost Gross Unrealized Gross Unrealized Fair Cash and cash equivalents: Cash $ 2,037 $ — $ — $ 2,037 Money market funds 1,436 — — 1,436 U.S. government agency securities 10,181 — — 10,181 Commercial paper 74,321 — — 74,321 Total cash and cash equivalents 87,975 — — 87,975 Short-term investments: U.S. government agency securities $ 1,497 $ — $ — $ 1,497 Commercial paper 16,243 — — 16,243 Total marketable securities and commercial paper 17,740 — — 17,740 Total cash, cash equivalents and investments $ 105,715 $ — $ — $ 105,715 As of December 31 , 201 7 Amortized Cost Gross Unrealized Gross Unrealized Fair Cash and cash equivalents: Cash $ 29,765 $ — $ — $ 29,765 U.S. government agency securities 23,137 — — 23,137 Total cash and cash equivalents 52,902 — — 52,902 Short-term investments: U.S. government agency securities $ 7,567 $ — $ — $ 7,567 Total marketable securities 7,567 — — 7,567 Total cash, cash equivalents and investments $ 60,469 $ — $ — $ 60,469
Fair Value Measurements, Recurring and Nonrecurring [Table Text Block]	As of December 31 , 201 8 Fair Value Level I Level II Level III Assets Money market funds $ 1,436 $ 1,436 $ — $ — U.S. government agency securities 11,678 — 11,678 — Commercial paper 90,564 — 90,564 — Total assets measured at fair value $ 103,678 $ 1,436 $ 102,242 $ — Liabilities Contingent put option liability $ 121 $ — $ — $ 121 Total liabilities measured at fair value $ 121 $ — $ — $ 121 As of December 31 , 201 7 Fair Value Level I Level II Level III Assets U.S. government agency securities $ 30,704 $ — $ 30,704 $ — Total assets measured at fair value $ 30,704 $ — $ 30,704 $ — Liabilities Contingent put option liability $ 207 $ — $ — $ 207 Total liabilities measured at fair value $ 207 $ — $ — $ 207
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block]	Year Ended 8 Fair value—beginning of period $ 207 Change in fair value of contingent put option associated with Amended Loan Agreement (86 ) Fair value—end of period $ 121 Year Ended 7 Fair value—beginning of period $ 412 Expiration of fair value of PIPE warrants (288 ) Change in fair value of contingent put option associated with Amended Loan Agreement 83 Fair value—end of period $ 207

Note 3 - Inventories (Tables)

Note 3 - Inventories (Tables)	12 Months Ended
	Dec. 31, 2018
Notes Tables
Schedule of Inventory, Current [Table Text Block]	As of December 31, 201 8 201 7 Raw materials $ 694 $ 702 Work-in-process 160 254 Inventories $ 854 $ 956

Note 4 - Property and Equipme_2

Note 4 - Property and Equipment (Tables)	12 Months Ended
	Dec. 31, 2018
Notes Tables
Property, Plant and Equipment [Table Text Block]	As of December 31, 201 8 201 7 Laboratory equipment $ 3,972 $ 3,920 Leasehold improvements 4,469 4,469 Computer equipment and software 237 241 Construction in process 10,593 9,703 Tooling 1,109 1,109 Furniture and fixtures 47 47 20,427 19,489 Less accumulated depreciation and amortization (8,944 ) (8,438 ) Property and equipment, net $ 11,483 $ 11,051

Note 5 - Adoption of ASC Topi_2

Note 5 - Adoption of ASC Topic 606, Revenue From Contracts With Customers (Tables)	12 Months Ended
	Dec. 31, 2018
Notes Tables
Contract with Customer, Asset and Liability [Table Text Block]	Balance at Beginning of the Period Additions Deductions Balance at the end of the Period (in thousands) Contract liability: Deferred revenue $ 3,825 $ - $ (362 ) $ 3,463
Disaggregation of Revenue [Table Text Block]	Year ended December 31 , 2018 Amounts included in contract liabilities at the beginning of the period: Performance obligations satisfied – Amended Agreements $ 362 New activities in the period from performance obligations satisfied: Performance obligations satisfied – Amended Agreements 566 Total revenue from performance obligations satisfied 928 Royalty revenue 385 Contract and other 838 Total revenue $ 2,151

Note 7 - Collaboration Agreem_2

Note 7 - Collaboration Agreement (Tables)	12 Months Ended
	Dec. 31, 2018
Notes Tables
Revenue Recognition Amended Agreements [Table Text Block]	Years Ended December 31, 201 8 2017 201 6 Product sales $ 825 $ 6,673 $ 5,742 Joint steering committee, research and development services and demonstration devices 103 269 688 Non-cash royalty revenue related to Royalty Monetization (See Note 9) 289 151 7 Royalty revenue 96 50 3 Total $ 1,313 $ 7,143 $ 6,440

Note 8 - Long-term Debt (Tables

Note 8 - Long-term Debt (Tables)	12 Months Ended
	Dec. 31, 2018
Notes Tables
Schedule of Maturities of Long-term Debt [Table Text Block]	2019 $ 9,437 2020 3,701 Total payments 13,138 Less amount representing interest (872 ) Notes payable, gross 12,266 Unamortized portion of final payment (229 ) Unamortized discount on notes payable (46 ) Long-term debt 11,991 Less current portion of notes payable, including unamortized discount (8,611 ) Long-term debt, current portion $ 3,380

Note 9 - Liability Related to_2

Note 9 - Liability Related to Sale of Future Royalties (Tables)	12 Months Ended
	Dec. 31, 2018
Notes Tables
Other Liabilities [Table Text Block]	Year ended 8 Period from inception to 8 Liability related to sale of future royalties — beginning balance $ 83,588 $ — Proceeds from sale of future royalties — 61,184 Non-cash royalty revenue (250 ) (377 ) Non-cash interest expense recognized 10,341 32,872 Liability related to sale of future royalties as of December 31, 2018 93,679 93,679 Less: current portion (392 ) (392 ) Liability related to sale of future royalties — net of current portion $ 93,287 $ 93,287

Note 11 - Commitments and Con_2

Note 11 - Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2018
Notes Tables
Schedule of Future Minimum Rental Payments for Operating Leases [Table Text Block]	Year Ending December 31: 2019 $ 1,230 2020 1,268 2021 1,305 2022 1,345 2023 1,386 Thereafter 116 Total minimum payments $ 6,650

Note 13 - Stock-based Compens_2

Note 13 - Stock-based Compensation (Tables)	12 Months Ended
	Dec. 31, 2018
Notes Tables
Schedule of Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Table Text Block]	December 31, 8 December 31, 7 December 31, 6 Cost of goods sold $ 358 $ 324 $ 302 Research and development 1,970 1,901 2,308 General and administrative 2,840 2,069 1,869 Total $ 5,168 $ 4,294 $ 4,479
Share-based Compensation, Stock Options, Activity [Table Text Block]	Number Weighted- Weighted- Aggregate (in thousands) December 31, 2017 8,455,098 $ 4.25 Granted 3,553,713 2.28 Forfeited (217,816 ) 2.87 Expired (232,905 ) 6.36 Exercised (135,385 ) 2.96 December 31, 2018 11,422,705 $ 3.64 7.1 $ 659 Vested and exercisable options—December 31, 2018 6,468,788 $ 4.44 5.8 $ 46 Vested and expected to vest—December 31, 2018 11,422,705 $ 3.64 7.1 $ 659
Schedule of Share-based Compensation, Stock Options Outstanding and Exercisable Activity [Table Text Block]	Options Outstanding Options Vested and Exercisable Exercise Prices Number of Weighted-Average Weighted-Average Shares Subject Weighted-Average $1.20 - $2.00 1,856,170 9.0 $ 2.00 6,900 $ 1.20 $2.225 - $3.35 5,406,951 7.8 $ 2.82 2,698,203 $ 2.82 $3.37 - $5.31 2,855,022 5.2 $ 4.13 2,459,123 $ 4.19 $5.45 - $8.18 688,562 5.0 $ 6.47 688,562 $ 6.47 $10.22 - $10.55 616,000 5.1 $ 10.34 616,000 $ 10.34 11,422,705 7.1 $ 3.64 6,468,788 $ 4.44
Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Table Text Block]	Year Ended December 31, 201 8 201 7 201 6 Expected term (in years) 5.89 5.70 5.25 - 6.25 Risk-free interest rate 2.5% - 3.1% 1.82% - 2.09% 1.24% - 1.47% Expected volatility 83% 73% 80% Expected dividend rate 0% 0% 0%

Note 14 - Net Loss Per Share _2

Note 14 - Net Loss Per Share of Common Stock (Tables)	12 Months Ended
	Dec. 31, 2018
Notes Tables
Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table Text Block]	Year Ended December 31, 201 8 201 7 201 6 ESPP and stock options to purchase common stock 11,797,960 8,767,783 6,395,879 Convertible debt into common stock — — 553,763 Common stock warrants — 176,730 692,611

Note 15 - Accrued Liabilities (

Note 15 - Accrued Liabilities (Tables)	12 Months Ended
	Dec. 31, 2018
Notes Tables
Schedule of Accrued Liabilities [Table Text Block]	December 31, 201 8 201 7 Accrued compensation and employee benefits $ 3,611 $ 2,190 Inventory and other contract manufacturing accruals 234 511 Other accrued liabilities 695 842 Total accrued liabilities $ 4,540 $ 3,543

Note 17 - Income Taxes (Tables)

Note 17 - Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2018
Notes Tables
Schedule of Components of Income Tax Expense (Benefit) [Table Text Block]	December 31, 8 December 31, 7 Current: Federal $ — $ (702 ) State 2 1 Total Current 2 (701 ) Deferred: Federal — — State — — Total Deferred — — Provision (benefit) for income taxes $ 2 $ (701 )
Schedule of Deferred Tax Assets [Table Text Block]	December 31, 8 December 31, 7 Deferred tax assets: Accruals and other $ 3,263 $ 2,717 Research credits 7,275 6,530 Net operating loss carryforward 39,082 31,064 Section 59(e) R&D expenditures 10,387 12,156 Deferred revenue 20,689 18,384 Total deferred tax assets 80,696 70,851 Valuation allowance (80,696 ) (70,851 ) Net deferred tax assets $ — $ —
Schedule of Effective Income Tax Rate Reconciliation [Table Text Block]	Year Ended December 31, 201 8 201 7 201 6 Tax at statutory federal rate $ (9,901 ) $ (17,751 ) $ (14,685 ) State tax—net of federal benefit (792 ) 350 (73 ) PIPE warrant liability (18 ) (70 ) (260 ) General business credits (500 ) (316 ) (360 ) Stock options 1,048 42 1,115 Other 313 51 33 Change in valuation allowance 9,852 (17,110 ) 14,196 Tax reform – tax rate change — 34,103 — Provision for income taxes $ 2 $ (701 ) $ (34 )
Schedule of Unrecognized Tax Benefits Roll Forward [Table Text Block]	Year Ended December 31, 2018 2017 2016 Unrecognized benefit—beginning of period $ 2,365 $ 2,162 $ 1,939 Gross increases—prior period tax positions 57 — — Gross increases—current period tax positions 213 203 223 Unrecognized benefit—end of period $ 2,635 $ 2,365 $ 2,162

Note 19 - Unaudited Quarterly_2

Note 19 - Unaudited Quarterly Financial Data (Tables)	12 Months Ended
	Dec. 31, 2018
Notes Tables
Quarterly Financial Information [Table Text Block]	201 8 2017 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Revenues $ 343 $ 818 $ 377 $ 613 $ 3,109 $ 2,659 $ 1,487 $ 740 Operating costs and expenses $ 8,612 $ 7,971 $ 9,705 $ 11,590 $ 15,182 $ 12,600 $ 10,348 $ 8,547 Net loss $ (11,592 ) $ (10,541 ) $ (12,458 ) $ (12,558 ) $ (15,551 ) $ (13,059 ) $ (13,013 ) $ (9,885 ) Net loss per share (basic and diluted) $ (0.23 ) $ (0.20 ) $ (0.21 ) $ (0.18 ) $ (0.34 ) $ (0.29 ) $ (0.28 ) $ (0.20 )

Reconciliation of Cash, Cash _3

Reconciliation of Cash, Cash Equivalents, and Restricted Cash - Schedule of Cash, Cash Equivalents, and Restricted Cash (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Cash and cash equivalents	$ 87,975	$ 52,902	$ 80,310
RESTRICTED CASH	178	178	178
CASH, CASH EQUIVALENTS AND RESTRICTED CASH SHOWN IN STATEMENT OF CASH FLOWS	$ 88,153	$ 53,080	$ 80,488	$ 108,100

Note 1 - Organization and Sum_2

Note 1 - Organization and Summary of Significant Accounting Policies (Details Textual) $ in Thousands	Sep. 18, 2015USD ($)	Sep. 30, 2015USD ($)	Dec. 31, 2018USD ($)	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015USD ($)	Dec. 31, 2018USD ($)
Proceeds From Sale of Royalty and Milestone Rights	$ 65,000	$ 65,000
Royalty Arrangment Maximum Payments	$ 195,000	195,000
Net Proceeds from Sale of Future Royalties		$ 61,200					$ 61,184
Interest Income [Member]
Asset Impairment Charges, Total			$ 0			$ 500
Sales Revenue, Net [Member] | Customer Concentration Risk [Member]
Number of Major Customers			2	2	2
Sales Revenue, Net [Member] | Customer Concentration Risk [Member] | Two Customers [Member]
Concentration Risk, Percentage			100.00%	100.00%	100.00%
Accounts Receivable [Member] | Customer Concentration Risk [Member] | One Customer [Member]
Concentration Risk, Percentage			100.00%	79.00%	71.00%

Note 2 - Investments and Fair_3

Note 2 - Investments and Fair Value Measurement (Details Textual) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Available-for-sale Securities, Gross, Unrealized Gain (Loss) Accumulated In Investments	$ 0	$ 0
Available-for-sale Securities, Gross Realized Gain (Loss), Total	0	0
Other than Temporary Impairment Losses, Investments, Available-for-sale Securities, Total	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_4

Note 2 - Investments and Fair Value Measurement - Summary of Cash, Cash Equivalents and Investments (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Amortized Cost	$ 105,715	$ 60,469
Gross Unrealized Gains
Gross Unrealized Losses
Fair Value	105,715	60,469
Cash and cash equivalents:
Amortized Cost	105,715	60,469
Gross Unrealized Gains
Gross Unrealized Losses
Fair Value	105,715	60,469
Cash and Cash Equivalents [Member]
Amortized Cost	87,975	52,902
Gross Unrealized Gains
Gross Unrealized Losses
Fair Value	87,975	52,902
Cash and cash equivalents:
Amortized Cost	87,975	52,902
Gross Unrealized Gains
Gross Unrealized Losses
Fair Value	87,975	52,902
Cash and Cash Equivalents [Member] | Cash [Member]
Amortized Cost	2,037	29,765
Gross Unrealized Gains
Gross Unrealized Losses
Fair Value	2,037	29,765
Cash and cash equivalents:
Amortized Cost	2,037	29,765
Gross Unrealized Gains
Gross Unrealized Losses
Fair Value	2,037	29,765
Cash and Cash Equivalents [Member] | Money Market Funds [Member]
Amortized Cost	1,436
Gross Unrealized Gains
Gross Unrealized Losses
Fair Value	1,436
Cash and cash equivalents:
Amortized Cost	1,436
Gross Unrealized Gains
Gross Unrealized Losses
Fair Value	1,436
Cash and Cash Equivalents [Member] | U.S. Government Agency Securities [Member]
Amortized Cost	10,181	23,137
Gross Unrealized Gains
Gross Unrealized Losses
Fair Value	10,181	23,137
Cash and cash equivalents:
Amortized Cost	10,181	23,137
Gross Unrealized Gains
Gross Unrealized Losses
Fair Value	10,181	23,137
Cash and Cash Equivalents [Member] | Commercial Paper [Member]
Amortized Cost	74,321
Gross Unrealized Gains
Gross Unrealized Losses
Fair Value	74,321
Cash and cash equivalents:
Amortized Cost	74,321
Gross Unrealized Gains
Gross Unrealized Losses
Fair Value	74,321
Marketable Securities [Member]
Amortized Cost	17,740	7,567
Gross Unrealized Gains
Gross Unrealized Losses
Fair Value	17,740	7,567
Cash and cash equivalents:
Amortized Cost	17,740	7,567
Gross Unrealized Gains
Gross Unrealized Losses
Fair Value	17,740	7,567
Marketable Securities [Member] | U.S. Government Agency Securities [Member]
Amortized Cost	1,497	7,567
Gross Unrealized Gains
Gross Unrealized Losses
Fair Value	1,497	7,567
Cash and cash equivalents:
Amortized Cost	1,497	7,567
Gross Unrealized Gains
Gross Unrealized Losses
Fair Value	1,497	$ 7,567
Marketable Securities [Member] | Commercial Paper [Member]
Amortized Cost	16,243
Gross Unrealized Gains
Gross Unrealized Losses
Fair Value	16,243
Cash and cash equivalents:
Amortized Cost	16,243
Gross Unrealized Gains
Gross Unrealized Losses
Fair Value	$ 16,243

Note 2 - Investments and Fair_5

Note 2 - Investments and Fair Value Measurement - Fair Value of Financial Assets and Liabilities by Level Within Fair Value Hierarchy (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Assets, fair value	$ 103,678	$ 30,704
Liabilities, fair value	121	207
Contingent Put Option Liability [Member]
Liabilities, fair value	121	207
Fair Value, Inputs, Level 1 [Member]
Assets, fair value	1,436
Liabilities, fair value
Fair Value, Inputs, Level 1 [Member] | Contingent Put Option Liability [Member]
Liabilities, fair value
Fair Value, Inputs, Level 2 [Member]
Assets, fair value	102,242	30,704
Liabilities, fair value
Fair Value, Inputs, Level 2 [Member] | Contingent Put Option Liability [Member]
Liabilities, fair value
Fair Value, Inputs, Level 3 [Member]
Assets, fair value
Liabilities, fair value	121	207
Fair Value, Inputs, Level 3 [Member] | Contingent Put Option Liability [Member]
Liabilities, fair value	121	207
Money Market Funds [Member]
Assets, fair value	1,436
Money Market Funds [Member] | Fair Value, Inputs, Level 1 [Member]
Assets, fair value	1,436
Money Market Funds [Member] | Fair Value, Inputs, Level 2 [Member]
Assets, fair value
Money Market Funds [Member] | Fair Value, Inputs, Level 3 [Member]
Assets, fair value
U.S. Government Agency Obligations [Member]
Assets, fair value	11,678	30,704
U.S. Government Agency Obligations [Member] | Fair Value, Inputs, Level 1 [Member]
Assets, fair value
U.S. Government Agency Obligations [Member] | Fair Value, Inputs, Level 2 [Member]
Assets, fair value	11,678	30,704
U.S. Government Agency Obligations [Member] | Fair Value, Inputs, Level 3 [Member]
Assets, fair value
Commercial Paper [Member]
Assets, fair value	90,564
Commercial Paper [Member] | Fair Value, Inputs, Level 1 [Member]
Assets, fair value
Commercial Paper [Member] | Fair Value, Inputs, Level 2 [Member]
Assets, fair value	90,564
Commercial Paper [Member] | Fair Value, Inputs, Level 3 [Member]
Assets, fair value

Note 2 - Investments and Fair_6

Note 2 - Investments and Fair Value Measurement - Summary of Changes in Fair Value of Level III Financial Liabilities (Details) - Fair Value, Inputs, Level 3 [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Fair value, Beginning of period	$ 207	$ 412
Fair value, End of period	121	207
Expiration of fair value of PIPE warrants		(288)
Hercules 2011 Loan and Security Agreement [Member]
Change in fair value of contingent put option associated with Amended Loan Agreement	$ (86)	$ 83

Note 3 - Inventories (Details T

Note 3 - Inventories (Details Textual) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Inventory Write-down		$ 369
ZALVISO [Member]
Inventory Write-down		$ 400

Note 3 - Inventories - Inventor

Note 3 - Inventories - Inventory Components (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Raw materials	$ 694	$ 702
Work-in-process	160	254
Inventories	$ 854	$ 956

Note 4 - Property and Equipme_3

Note 4 - Property and Equipment (Details Textual) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Depreciation, Total	$ 0.5	$ 1.7	$ 2.1

Note 4 - Property and Equipme_4

Note 4 - Property and Equipment - Components of Property and Equipment (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Property and Equipment, Gross	$ 20,427	$ 19,489
Less accumulated depreciation and amortization	(8,944)	(8,438)
Property and equipment, net	11,483	11,051
Laboratory Equipment [Member]
Property and Equipment, Gross	3,972	3,920
Leasehold Improvements [Member]
Property and Equipment, Gross	4,469	4,469
Computer Equipment and Software [Member]
Property and Equipment, Gross	237	241
Construction in Progress [Member]
Property and Equipment, Gross	10,593	9,703
Tooling [Member]
Property and Equipment, Gross	1,109	1,109
Furniture and Fixtures [Member]
Property and Equipment, Gross	$ 47	$ 47

Note 5 - Adoption of ASC Topi_3

Note 5 - Adoption of ASC Topic 606, Revenue From Contracts With Customers (Details Textual) $ in Millions	12 Months Ended
	Dec. 31, 2018USD ($)
Discount on Manufacturing Services	$ 3.5

Note 5 - Adoption of ASC Topi_4

Note 5 - Adoption of ASC Topic 606, Revenue From Contracts With Customers - Changes in Contract Liabilities (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2018USD ($)
Contract Liabilities: Deferred Revenue	$ 3,825
Contract Liabilities: Deferred Revenue, Deductions	(362)
Contract Liabilities: Deferred Revenue	$ 3,463

Note 5 - Adoption of ASC Topi_5

Note 5 - Adoption of ASC Topic 606, Revenue From Contracts With Customers - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Amounts included in contract liabilities at the beginning of the period: Performance obligations satisfied – Amended Agreements									$ 362
New activities in the period from performance obligations satisfied: Performance obligations satisfied – Amended Agreements									566
Total revenue from performance obligations satisfied									928
Revenue	$ 613	$ 377	$ 818	$ 343	$ 740	$ 1,487	$ 2,659	$ 3,109	2,151	$ 7,995	$ 17,357
Royalty Revenue [Member]
Revenue									385
Contract and Other [Member]
Revenue									$ 838	$ 852	$ 10,917

Note 6 - U.S. Department of D_2

Note 6 - U.S. Department of Defense Funding (Details Textual) - USD ($) $ in Thousands	Feb. 28, 2018	Mar. 09, 2017	Mar. 02, 2016	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	May 11, 2015
Government Contract Receivable							$ 17,000
Revenue from Contract with Customer, Including Assessed Tax				$ 928
Amendment to DoD Contract Incorporate Additional Services [Member]
Government Contract Receivable	$ 500
Award Contract Renewal Term	1 year
Government [Member]
Award Contract Renewal Term		330 days	120 days
Government [Member] | Contract and Other Revenue [Member]
Revenue from Contract with Customer, Including Assessed Tax				$ 800	$ 900	$ 10,900

Note 7 - Collaboration Agreem_3

Note 7 - Collaboration Agreement (Details Textual) - USD ($) $ in Thousands	Jul. 17, 2015	Dec. 31, 2018	Sep. 30, 2015	Dec. 31, 2013	Sep. 30, 2014	Sep. 30, 2015	Jul. 16, 2015	Dec. 15, 2018	Dec. 31, 2017
Payments in Exchange for Services Under Collaboration Agreement	$ 700
Amount of Binding Product Forecast Revenue	3,700
Revenue Recognition Milestone Method Agreed, Additional Amount, Based On Efforts And Targets	194,500
Manufacturing Agreement, Percentage for Five Years								100.00%
Manufacturing Agreement, Percentage, Thereafter		80.00%
Deferred Revenue, Current		$ 315							$ 362
Deferred Revenue, Noncurrent		3,148							$ 3,463
Amended License Agreement [Member]
Proceeds from Collaborators				$ 30,000
Amended License Agreement [Member] | Europe [Member]
Revenue from Contract with Customer, Excluding Assessed Tax, Total			$ 15,000		$ 5,000	$ 20,000
Amended License Agreement [Member] | AUSTRALIA
Remaining Potential Milestone Payment		$ 1,000
Based upon Net Sales Target Achievements [Member]
Increase (Decrease) in Milestone Payments Related to Net Sales Target	5,500
Potential Milestone Payments Related to Net Sales Target	166,000						$ 171,500
Revenue Recognition Milestone Method Agreed, Additional Amount, Based On Efforts And Targets	166,000
Based upon Successful Regulatory and Product Development Efforts [Member]
Revenue Recognition Milestone Method Agreed, Additional Amount, Based On Efforts And Targets	$ 28,500

Note 7 - Collaboration Agreem_4

Note 7 - Collaboration Agreement - Summary of Revenue Recognized Under the Amended Agreements (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Non-cash royalty revenue related to Royalty Monetization (See Note 9)	$ 289	$ 151	$ 7
Total revenue from performance obligations satisfied	928
Collaborative Arrangement [Member]
Revenue Recognized	103	269	688
Non-cash royalty revenue related to Royalty Monetization (See Note 9)	289	151	7
Total	1,313	7,143	6,440
Collaborative Arrangement [Member] | ZALVISO [Member] | Grunenthal [Member]
Revenue Recognized	825	6,673	5,742
Collaborative Arrangement [Member] | Royalty [Member]
Total revenue from performance obligations satisfied	$ 96	$ 50	$ 3

Note 8 - Long-term Debt (Detail

Note 8 - Long-term Debt (Details Textual) $ / shares in Units, $ in Thousands	Mar. 02, 2017USD ($)	Sep. 30, 2016$ / sharesshares	Sep. 18, 2015$ / sharesshares	Dec. 16, 2013USD ($)$ / sharesshares	Sep. 30, 2016$ / shares	Dec. 31, 2013$ / sharesshares	Jun. 30, 2016$ / shares	Mar. 01, 2020	Mar. 01, 2019	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)	Oct. 01, 2017USD ($)	Sep. 17, 2015$ / shares	Dec. 31, 2014USD ($)	Sep. 24, 2014USD ($)	Jun. 16, 2014USD ($)
Repayments of Long-term Debt, Total										$ 7,718	$ 3,514
Fair Value of Contingent Put Option, Liability										121	207
Interest Expense, Total										2,217	3,316	$ 2,770
Hercules Warrants [Member]
Common Stock Warrants Exercised | shares		176,730	176,730	176,730		176,730
Class of Warrant or Right, Exercise Price of Warrants or Rights | $ / shares		$ 3.07	$ 3.88	$ 6.79	$ 3.07	$ 9.67								$ 6.79
Investment Warrants, Exercise Price | $ / shares					$ 3.07	$ 6.79	$ 3.88
Amended and Restated Loan and Security Agreement [Member]
Line of Credit Facility, Maximum Borrowing Capacity				$ 40,000
Number of Tranches for Loan and Security Agreement				3
Debt Instrument, Fair Value Disclosure, Total															$ 24,900
Long-term Debt Maturities Balloon Payments													$ 1,700
Debt Instrument, Variable Rate Threshold	9.55%
Debt Instrument, Percentage Used to Calculate Variable Rate	3.50%
Debt Instrument, Final Payment, Percentage of Aggregate Principal Amount	6.50%
Amended and Restated Loan and Security Agreement [Member] | Prime Rate [Member]
Debt Instrument, Interest Rate, Effective Percentage												9.55%
Amended and Restated Loan and Security Agreement [Member] | First Tranche [Member]
Debt Instrument, Face Amount				$ 15,000
Repayments of Long-term Debt, Total				8,600
Amended and Restated Loan and Security Agreement [Member] | Second Tranche [Member]
Debt Instrument, Face Amount																	$ 10,000
Amended and Restated Loan and Security Agreement [Member] | Third Tranche [Member]
Line of Credit Facility, Maximum Borrowing Capacity																$ 15,000
Hercules Loan and Security Agreement [Member]
Additional Default Interest Rate	5.00%
Fair Value of Contingent Put Option, Liability				$ 32						100	200
Long-term Line of Credit, Total										12,000	19,100
Interest Expense, Total										$ 2,200	$ 3,300	$ 2,800
Hercules Loan and Security Agreement [Member] | Scenario, Forecast [Member]
Prepayment Charge of Term Loan Percentage								1.00%	2.00%
Hercules Loan and Security Agreement [Member] | First Tranche [Member]
Debt Instrument, Face Amount	$ 20,500

Note 8 - Long-term Debt - Outst

Note 8 - Long-term Debt - Outstanding Future Payments of Long-term Debt (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
2,019	$ 9,437
2,020	3,701
Total payments	13,138
Less amount representing interest	(872)
Notes payable, gross	12,266
Unamortized portion of final payment	(229)
Unamortized discount on notes payable	(46)
Long-term debt	11,991
Less current portion of notes payable, including unamortized discount	(8,611)	$ (7,727)
Long-term debt, current portion	$ 3,380	$ 11,369

Note 9 - Liability Related to_3

Note 9 - Liability Related to Sale of Future Royalties (Details Textual) - USD ($) $ in Thousands	Sep. 18, 2015	Sep. 30, 2015	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2018
Proceeds From Sale of Royalty and Milestone Rights	$ 65,000	$ 65,000
Royalty Arrangment Maximum Payments	$ 195,000	$ 195,000
Effective Annual Interest Rate				11.60%	13.60%	13.70%	13.00%
ZALVISO [Member] | Scenario, Forecast [Member]
Effective Annual Interest Rate			7.00%
First Four Commercial Milestones [Member]
Percentage of Royalties and Rights Under Agreement	20.00%
Royalties [Member]
Percentage of Royalties and Rights Under Agreement	25.00%
Remaining Commercial and All Development Milestone[Member]
Percentage of Royalties and Rights Under Agreement	100.00%
Commercial Milestones Value	$ 43,500
MAA Approval [Member]
Revenue Recognition Milestone Method Agreed, Additional Amount	15,000
PDL [Member]
Proceeds From Sale of Royalty and Milestone Rights	$ 61,200
Percentage of Royalties and Rights Under Agreement	75.00%
PDL [Member] | First Four Commercial Milestones [Member]
Percentage of Royalties and Rights Under Agreement	80.00%
Commercial Milestones Value Maximum Amount Available	$ 35,600
AcelRX [Member] | First Four Commercial Milestones [Member]
Commercial Milestones Value Maximum Amount Available	$ 44,500

Note 9 - Liability Related to_4

Note 9 - Liability Related to Sale of Future Royalties - Activity of Liability Related to Sale of Future Royalties (Details) - USD ($) $ in Thousands	1 Months Ended	12 Months Ended			39 Months Ended
	Sep. 30, 2015	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2018
Liability related to sale of future royalties — beginning balance		$ 83,588
Proceeds from sale of future royalties	$ 61,200				61,184
Non-cash royalty revenue		(250)			(377)
Non-cash interest expense recognized		10,341	$ 10,721	$ 9,382	32,872
Liability related to sale of future royalties as of December 31, 2018		93,679	83,588		93,679
Less: current portion		(392)	(604)		(392)
Liability related to sale of future royalties — net of current portion		$ 93,287	$ 82,984		$ 93,287

Note 10 - Warrants (Details Tex

Note 10 - Warrants (Details Textual) $ / shares in Units, $ in Thousands	Sep. 30, 2016USD ($)$ / sharesshares	Sep. 18, 2015$ / sharesshares	Dec. 16, 2013$ / sharesshares	Sep. 30, 2016USD ($)$ / shares	Dec. 31, 2013USD ($)$ / shares$ / itemshares	Jun. 30, 2012USD ($)$ / sharesshares	Jun. 30, 2016$ / shares	Dec. 31, 2017USD ($)shares	Dec. 31, 2016USD ($)	Dec. 31, 2018shares	Sep. 30, 2015USD ($)	Sep. 17, 2015$ / shares
Hercules Warrants [Member]
Common Stock Warrants Exercised | shares	176,730	176,730	176,730		176,730
Investment Warrants, Exercise Price | $ / shares				$ 3.07	$ 6.79		$ 3.88
Class of Warrant or Right, Exercise Price of Warrants or Rights | $ / shares	$ 3.07	$ 3.88	$ 6.79	$ 3.07	$ 9.67							$ 6.79
Warrant Exercisable Term					5 years
Fair Value of Warrant On Date Of Issuance | $	$ 45			$ 45	$ 1,100						$ 100
Derivative, Price Risk Option Strike Price | $ / item					6.79
Class of Warrant or Right Fair Value Assumption Risk Free Interest Rate					1.55%
Class of Warrant or Right Fair Value Assumption Stock Volatility					71.00%
Class of Warrant or Right Fair Value Assumption Expected Dividend Yield					0.00%
Class of Warrant or Right, Outstanding | shares										176,730
PIPE Warrants [Member]
Investment Warrants, Exercise Price | $ / shares						$ 3.40
Warrant Exercisable Term						5 years
Class of Warrant or Right, Outstanding | shares						2,630,103		512,456
Warrants Vesting Condition Description						50.00%
2012 Private Placement [Member]
Fair Value of Warrant Upon Execution of Securities Purchase Agreement | $						$ 5,800
2012 Private Placement [Member] | Nonoperating Income (Expense) [Member]
Fair Value Adjustment of Warrants | $								$ (300)	$ (600)

Note 11 - Commitments and Con_3

Note 11 - Commitments and Contingencies (Details Textual)	Jun. 14, 2017USD ($)a	Oct. 02, 2015ft²$ / item	May 31, 2014ft²	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)	Feb. 16, 2019USD ($)ft²	Dec. 31, 2011ft²
Rental Rate Per Square Foot | $ / item		2.05
Sublease Income				$ 25,000	$ 300,000
Operating Leases, Rent Expense, Net, Total				$ 1,100,000	$ 600,000	$ 300,000
Redwood City, California [Member]
Area of Operating Lease | ft²		11,871						13,787
Lessee, Operating Lease, Term of Contract		2 years 60 days
Lease Extended Term [Member]
Area of Operating Lease | ft²			12,106
Lessee, Operating Lease, Renewal Term			1 year 261 days
Lease Agreement, Term			3 years 180 days
Executive Offices in Redwood City, CA [Member] | Metropolitan Life Insurance Company [Member]
Lessee, Operating Lease, Renewal Term	6 years
Area of Real Estate Property | a	25,893
Operating Lease, Annual Rent	$ 1,200,000
Lessee, Operating Lease, Term for Annual Rent Increase	1 year
Expansion Space Sublease [Member] | Subsequent Event [Member]
Area of Operating Lease | ft²							12,106
Operating Leases, Future Monthly Payments Due, Future Minimum Sublease Rentals							$ 48,000

Note 11 - Commitments and Con_4

Note 11 - Commitments and Contingencies - Future Minimum Payments Under Lease Agreement (Details) $ in Thousands	Dec. 31, 2018USD ($)
2,019	$ 1,230
2,020	1,268
2,021	1,305
2,022	1,345
2,023	1,386
Thereafter	116
Total minimum payments	$ 6,650

Note 12 - Stockholders' Equity

Note 12 - Stockholders' Equity (Details Textual) - USD ($) $ / shares in Units, $ in Thousands	Nov. 14, 2018	Nov. 14, 2018	Nov. 12, 2018	Aug. 07, 2018	Jul. 16, 2018	Jun. 21, 2016	Feb. 10, 2011	Aug. 07, 2018	Nov. 30, 2009	Feb. 29, 2008	Aug. 31, 2006	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2011
Proceeds from Issuance of Common Stock, Net												$ 81,525	$ 15,694
Employee Stock Purchase Plan, Shares Issued, Weighted Average Fair Value												$ 1.51	$ 2.59	$ 2.98
2006 Equity Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized											342,000
Share-based Compensation Arrangement by Share-based Payment Award, Number of Additional Shares Authorized									1,400,000	375,000
2006 Equity Incentive Plan [Member] | Minimum [Member]
Common Stock Voting Rights Percentage											10.00%
2006 Equity Incentive Plan [Member] | Maximum [Member]
Fair Value of Common Stock as Percentage of Option Exercise Price											110.00%
2011 Equity Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized															1,800,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other Than Options, Outstanding							52,000								1,900,000
Stock Option Plan Option Reserve Annual Increase as Percentage of Outstanding Shares Allowed															4.00%
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period															4 years
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant												1,217,341
2011 Equity Incentive Plan [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period															10 years
Employee Stock Purchase Plan (ESPP) [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized															250,000
Share-based Payment Award, Number of Shares Authorized															2.00%
Stock Issued During Period, Shares, Employee Stock Purchase Plans												858,889
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant												182,360
Public Offering [Member]
Proceeds from Issuance Initial Public Offering						$ 40,000
Underwritten Public Offering [Member]
Stock Issued During Period, Shares, New Issues	14,603,173	12,698,412	1,904,761	1,090,909	7,272,727			8,363,636
Shares Issued, Price Per Share	$ 3.15	$ 3.15	$ 3.15	$ 2.75	$ 2.75			$ 2.75
Proceeds from Issuance of Common Stock	$ 46,000							$ 23,000
Proceeds from Issuance of Common Stock, Net	$ 43,100							$ 21,700
ATM Agreement 2016 [Member]
Stock Issued During Period, Shares, New Issues												4,400,000	5,400,000
Proceeds from Issuance of Common Stock, Net												$ 16,800	$ 15,700
Payments of Stock Issuance Costs												$ 400	$ 500

Note 13 - Stock-based Compens_3

Note 13 - Stock-based Compensation (Details Textual) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended	12 Months Ended
	Jan. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value		$ 1.62	$ 1.91	$ 2.24
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Total		$ 7,500
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition		2 years 146 days
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested in Period, Fair Value		$ 4,900	$ 3,500	$ 3,900
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Intrinsic Value		$ 200	$ 40	$ 0
2011 Equity Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant		1,217,341
2011 Equity Incentive Plan [Member] | Subsequent Event [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Additional Shares Authorized	3,150,317

Note 13 - Stock-based Compens_4

Note 13 - Stock-based Compensation - Stock-based Compensation Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Stock-based compensation expense	$ 5,168	$ 4,294	$ 4,479
Cost of Sales [Member]
Stock-based compensation expense	358	324	302
Research and Development Expense [Member]
Stock-based compensation expense	1,970	1,901	2,308
General and Administrative Expense [Member]
Stock-based compensation expense	$ 2,840	$ 2,069	$ 1,869

Note 13 - Stock-based Compens_5

Note 13 - Stock-based Compensation - Option Activity (Details) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2018USD ($)$ / sharesshares
Outstanding (in shares) | shares	8,455,098
Outstanding (in dollars per share) | $ / shares	$ 4.25
Granted (in shares) | shares	3,553,713
Granted, weighted-average exercise price (in dollars per share) | $ / shares	$ 2.28
Forfeited (in shares) | shares	(217,816)
Forfeited, weighted-average exercise price (in dollars per share) | $ / shares	$ 2.87
Expired (in shares) | shares	(232,905)
Expired, weighted-average exercise price (in dollars per share) | $ / shares	$ 6.36
Exercised (in shares) | shares	(135,385)
Exercised, weighted-average exercise price (in dollars per share) | $ / shares	$ 2.96
Outstanding (in shares) | shares	11,422,705
Outstanding, weighted-average exercise price (in dollars per share) | $ / shares	$ 3.64
Outstanding, weighted-average remaining contractual life (Year)	7 years 36 days
Outstanding, aggregate intrinsic value | $	$ 659
Vested and exercisable options (in shares) | shares	6,468,788
Vested and exercisable options, weighted-average exercise price (in dollars per share) | $ / shares	$ 4.44
Vested and exercisable options, weighted-average remaining contractual life (Year)	5 years 292 days
Vested and exercisable options, aggregate intrinsic value | $	$ 46
Vested and expected to vest (in shares) | shares	11,422,705
Vested and expected to vest, weighted-average exercise price (in dollars per share) | $ / shares	$ 3.64
Vested and expected to vest, weighted-average remaining contractual life (Year)	7 years 36 days
Vested and expected to vest, aggregate intrinsic value | $	$ 659

Note 13 - Stock-based Compens_6

Note 13 - Stock-based Compensation - Stock Options Outstanding, Vested and Exercisable (Details) - $ / shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Number of Stock Options Outstanding (in shares)	11,422,705	8,455,098
Weighted-average Remaining Contractual LIfe (Year)	7 years 36 days
Options Outstanding, Weighted-average Exercise Price Per Share (in dollars per share)	$ 3.64	$ 4.25
Shares Subject to Stock Options (in shares)	6,468,788
Options Vested and Exercisable, Weighted-average Exercise Price Per Share (in dollars per share)	$ 4.44
Exercise Price Range 1 [Member]
Exercise Price Range, Lower Range Limit (in dollars per share)	1.20
Exercise Price Range, Upper Range Limit (in dollars per share)	$ 2
Number of Stock Options Outstanding (in shares)	1,856,170
Weighted-average Remaining Contractual LIfe (Year)	9 years
Options Outstanding, Weighted-average Exercise Price Per Share (in dollars per share)	$ 2
Shares Subject to Stock Options (in shares)	6,900
Options Vested and Exercisable, Weighted-average Exercise Price Per Share (in dollars per share)	$ 1.20
Exercise Price Range 2 [Member]
Exercise Price Range, Lower Range Limit (in dollars per share)	2.225
Exercise Price Range, Upper Range Limit (in dollars per share)	$ 3.35
Number of Stock Options Outstanding (in shares)	5,406,951
Weighted-average Remaining Contractual LIfe (Year)	7 years 292 days
Options Outstanding, Weighted-average Exercise Price Per Share (in dollars per share)	$ 2.82
Shares Subject to Stock Options (in shares)	2,698,203
Options Vested and Exercisable, Weighted-average Exercise Price Per Share (in dollars per share)	$ 2.82
Exercise Price Range 3 [Member]
Exercise Price Range, Lower Range Limit (in dollars per share)	3.37
Exercise Price Range, Upper Range Limit (in dollars per share)	$ 5.31
Number of Stock Options Outstanding (in shares)	2,855,022
Weighted-average Remaining Contractual LIfe (Year)	5 years 73 days
Options Outstanding, Weighted-average Exercise Price Per Share (in dollars per share)	$ 4.13
Shares Subject to Stock Options (in shares)	2,459,123
Options Vested and Exercisable, Weighted-average Exercise Price Per Share (in dollars per share)	$ 4.19
Exercise Price Range 4 [Member]
Exercise Price Range, Lower Range Limit (in dollars per share)	5.45
Exercise Price Range, Upper Range Limit (in dollars per share)	$ 8.18
Number of Stock Options Outstanding (in shares)	688,562
Weighted-average Remaining Contractual LIfe (Year)	5 years
Options Outstanding, Weighted-average Exercise Price Per Share (in dollars per share)	$ 6.47
Shares Subject to Stock Options (in shares)	688,562
Options Vested and Exercisable, Weighted-average Exercise Price Per Share (in dollars per share)	$ 6.47
Exercise Price Range 5 [Member]
Exercise Price Range, Lower Range Limit (in dollars per share)	10.22
Exercise Price Range, Upper Range Limit (in dollars per share)	$ 10.55
Number of Stock Options Outstanding (in shares)	616,000
Weighted-average Remaining Contractual LIfe (Year)	5 years 36 days
Options Outstanding, Weighted-average Exercise Price Per Share (in dollars per share)	$ 10.34
Shares Subject to Stock Options (in shares)	616,000
Options Vested and Exercisable, Weighted-average Exercise Price Per Share (in dollars per share)	$ 10.34

Note 13 - Stock-based Compens_7

Note 13 - Stock-based Compensation - Assumptions to Calculate Fair Value of Each Employee Stock Option (Details)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Expected term (Year)	5 years 324 days	5 years 255 days
Expected volatility	83.00%	73.00%	80.00%
Expected dividend rate	0.00%	0.00%	0.00%
Minimum [Member]
Expected term (Year)			5 years 91 days
Risk-free interest rate	2.50%	1.82%	1.24%
Expected volatility
Expected dividend rate
Maximum [Member]
Expected term (Year)			6 years 91 days
Risk-free interest rate	3.10%	2.09%	1.47%
Expected volatility
Expected dividend rate

Note 14 - Net Loss Per Share _3

Note 14 - Net Loss Per Share of Common Stock - Common Stock Excluded from Computation of Diluted Net Loss Per Share (Details) - shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
ESPP and Employee Stock Options [Member]
Antidilutive securities (in shares)	11,797,960	8,767,783	6,395,879
Convertible Debt Securities [Member]
Antidilutive securities (in shares)			553,763
Warrant [Member]
Antidilutive securities (in shares)		176,730	692,611

Note 15 - Accrued Liabilities -

Note 15 - Accrued Liabilities - Accrued Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Accrued compensation and employee benefits	$ 3,611	$ 2,190
Inventory and other contract manufacturing accruals	234	511
Other accrued liabilities	695	842
Total accrued liabilities	$ 4,540	$ 3,543

Note 16 - 401(k) Plan (Details

Note 16 - 401(k) Plan (Details Textual) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Defined Contribution Plan, Employer Discretionary Contribution Percentage	4.00%
Contributions by Employer to Postemployment Benefit Obligations	$ 0.3	$ 0.3	$ 0.3

Note 17 - Income Taxes (Details

Note 17 - Income Taxes (Details Textual) - USD ($)	3 Months Ended	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Expense (Benefit), Total		$ 2,000	$ (701,000)	$ (34,000)
SEC Schedule, 12-09, Valuation Allowances and Reserves, Period Increase (Decrease), Total		9,900,000	(17,100,000)	14,200,000
Income Taxes Receivable, Current		352,000
Income Taxes Receivable, Noncurrent	703,000	$ 351,000	$ 703,000
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent		21.00%	35.00%
Tax Adjustments, Settlements, and Unusual Provisions	(700,000)
Income Tax Expense (Benefit), Continuing Operations, Adjustment of Deferred Tax (Asset) Liability	0
Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued, Total	0	$ 0	$ 0	$ 0
Subject to Expiration [Member]
Operating Loss Carryforwards, Total		$ 1,400,000
Research Tax Credit Carryforward [Member] | Subject to Expiration [Member]
Tax Credit Carryforward, Amount	26,000		26,000
Earliest Tax Year [Member]
Open Tax Year		2,005
Latest Tax Year [Member]
Open Tax Year		2,018
Domestic Tax Authority [Member]
Operating Loss Carryforwards, Total	114,900,000	$ 153,200,000	114,900,000
Deferred Tax Assets, Tax Credit Carryforwards, Alternative Minimum Tax	700,000		700,000
Income Taxes Receivable, Current	400,000		400,000
Income Taxes Receivable, Noncurrent	300,000		300,000
Domestic Tax Authority [Member] | Accounting Standards Update 2016-09 [Member]
Operating Loss Carryforwards, Total	2,900,000		2,900,000
Domestic Tax Authority [Member] | Research Tax Credit Carryforward [Member]
Tax Credit Carryforward, Amount		6,500,000
Domestic Tax Authority [Member] | Tax Year 2018 [Member]
SEC Schedule, 12-09, Valuation Allowances and Reserves, Period Increase (Decrease), Total		38,300,000
State and Local Jurisdiction [Member]
Operating Loss Carryforwards, Total		97,200,000
State and Local Jurisdiction [Member] | Accounting Standards Update 2016-09 [Member]
Operating Loss Carryforwards, Total	$ 2,000,000		$ 2,000,000
State and Local Jurisdiction [Member] | Research Tax Credit Carryforward [Member]
Tax Credit Carryforward, Amount		$ 4,000,000

Note 17 - Income Taxes - Provis

Note 17 - Income Taxes - Provision (Benefit) for Income Taxes (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Current:
Federal		$ (702,000)
State	2,000	1,000
Total Current	2,000	(701,000)
Deferred:
Federal
State
Total Deferred
Provision (benefit) for income taxes	$ 2,000	$ (701,000)	$ (34,000)

Note 17 - Income Taxes - Net De

Note 17 - Income Taxes - Net Deferred Tax Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Accruals and other	$ 3,263	$ 2,717
Research credits	7,275	6,530
Net operating loss carryforward	39,082	31,064
Section 59(e) R&D expenditures	10,387	12,156
Deferred revenue	20,689	18,384
Total deferred tax assets	80,696	70,851
Valuation allowance	(80,696)	(70,851)
Net deferred tax assets		$ 0

Note 17 - Income Taxes - Reconc

Note 17 - Income Taxes - Reconciliation of Statutory Federal Income Tax (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Tax at statutory federal rate	$ (9,901,000)	$ (17,751,000)	$ (14,685,000)
State tax—net of federal benefit	(792,000)	350,000	(73,000)
PIPE warrant liability	(18,000)	(70,000)	(260,000)
General business credits	(500,000)	(316,000)	(360,000)
Stock options	1,048,000	42,000	1,115,000
Other	313,000	51,000	33,000
Change in valuation allowance	9,852,000	(17,110,000)	14,196,000
Tax reform – tax rate change		34,103,000
Provision (benefit) for income taxes	$ 2,000	$ (701,000)	$ (34,000)

Note 17 - Income Taxes - Reco_2

Note 17 - Income Taxes - Reconciliation of Beginning and Ending Balance of Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Unrecognized benefit—beginning of period	$ 2,365	$ 2,162	$ 1,939
Gross increases—prior period tax positions	57
Gross increases—current period tax positions	213	203	223
Unrecognized benefit—end of period	$ 2,635	$ 2,365	$ 2,162

Note 18 - Subsequent Event (Det

Note 18 - Subsequent Event (Details Textual) - Expansion Space Sublease [Member] - Subsequent Event [Member]	Feb. 16, 2019USD ($)ft²
Area of Operating Lease | ft²	12,106
Operating Leases, Future Minimum Payments Due, Future Minimum Sublease Rentals | $	$ 48,000

Note 19 - Unaudited Quarterly_3

Note 19 - Unaudited Quarterly Financial Data - Quarterly Financial Data (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Revenue	$ 613	$ 377	$ 818	$ 343	$ 740	$ 1,487	$ 2,659	$ 3,109	$ 2,151	$ 7,995	$ 17,357
Total operating costs and expenses	11,590	9,705	7,971	8,612	8,547	10,348	12,600	15,182	37,878	46,677	49,314
Net loss	$ (12,558)	$ (12,458)	$ (10,541)	$ (11,592)	$ (9,885)	$ (13,013)	$ (13,059)	$ (15,551)	$ (47,149)	$ (51,508)	$ (43,157)
Net loss per share of common stock, basic and diluted (in dollars per share)	$ (0.18)	$ (0.21)	$ (0.20)	$ (0.23)	$ (0.20)	$ (0.28)	$ (0.29)	$ (0.34)	$ (0.81)	$ (1.10)	$ (0.95)