DURECT (DRRX) 10-K 8 Mar 18 2017 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2017	Mar. 02, 2018	Jun. 30, 2017
Document And Entity Information [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2017
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	FY
Trading Symbol	DRRX
Entity Registrant Name	DURECT CORP
Entity Central Index Key	1,082,038
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	No
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Accelerated Filer
Entity Common Stock, Shares Outstanding		153,336,970
Entity Public Float			$ 135,648,965

Balance Sheets

Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 29,375	$ 5,404
Short-term investments	7,384	19,600
Accounts receivable (net of allowances of $155 at December 31, 2017 and $73 at December 31, 2016)	2,376	1,154
Inventories	3,163	3,782
Prepaid expenses and other current assets	3,060	2,486
Total current assets	45,358	32,426
Property and equipment, net	929	1,297
Goodwill	6,399	6,399
Long-term restricted investments	150	150
Other long-term assets	277	236
Total assets	53,113	40,508
Current liabilities:
Accounts payable	1,520	2,086
Accrued liabilities	5,511	5,060
Contract research liabilities	834	783
Deferred revenue, current portion	682	968
Term loan, current portion, net	7,281	19,853
Total current liabilities	15,828	28,750
Deferred revenue, non-current portion	1,093	1,879
Term loan, non-current portion, net	12,634
Other long-term liabilities	2,070	1,541
Commitments and contingencies
Stockholders’ equity:
Preferred stock, $0.0001 par value: 10,000 shares authorized; none issued and outstanding
Common stock, $0.0001 par value: 200,000 shares authorized; 150,837 and 141,297 shares issued and outstanding at December 31, 2017 and 2016, respectively	15	14
Additional paid-in capital	465,246	448,404
Accumulated other comprehensive loss	(1)	(3)
Accumulated deficit	(443,772)	(440,077)
Stockholders’ equity	21,488	8,338
Total liabilities and stockholders’ equity	$ 53,113	$ 40,508

Balance Sheets (Parenthetical)

Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Statement Of Financial Position [Abstract]
Allowances for accounts receivable	$ 155	$ 73
Preferred stock, par value	$ 0.0001	$ 0.0001
Preferred stock, shares authorized	10,000,000	10,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, shares authorized	200,000,000	200,000,000
Common stock, shares issued	150,837,000	141,297,000
Common stock, shares outstanding	150,837,000	141,297,000

Statements of Operations And Co

Statements of Operations And Comprehensive Loss - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Statement [Abstract]
Collaborative research and development and other revenue	$ 23,577	$ 1,880	$ 7,832
Product revenue, net	13,093	12,145	11,292
Revenue from sale of intellectual property rights	12,500
Total revenues	49,170	14,025	19,124
Operating expenses:
Cost of product revenues	6,633	5,290	3,905
Research and development	31,609	29,274	24,317
Selling, general and administrative	13,165	11,825	11,566
Total operating expenses	51,407	46,389	39,788
Loss from operations	(2,237)	(32,364)	(20,664)
Other income (expense):
Interest and other income	967	143	237
Interest expense	(2,425)	(2,288)	(2,236)
Net other expense	(1,458)	(2,145)	(1,999)
Net loss	(3,695)	(34,509)	(22,663)
Net change in unrealized gain (loss) on available-for-sale securities, net of tax	2	11	(101)
Total comprehensive loss	$ (3,693)	$ (34,498)	$ (22,764)
Net loss per share
Basic	$ (0.03)	$ (0.26)	$ (0.19)
Diluted	$ (0.03)	$ (0.26)	$ (0.19)
Weighted-average shares used in computing net loss per share
Basic	145,273	133,163	118,523
Diluted	145,273	133,163	118,523

Statement of Stockholders' Equi

Statement of Stockholders' Equity - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock [Member]	Additional paid-in capital [Member]	Accumulated other comprehensive income [Member]	Accumulated deficit [Member]
Beginning balance at Dec. 31, 2014	$ 18,515	$ 11	$ 401,322	$ 87	$ (382,905)
Beginning balance, shares at Dec. 31, 2014		113,733
Issuance of common stock upon exercise of stock options and purchases of ESPP shares	1,175		1,175
Issuance of common stock upon exercise of stock options and purchases of ESPP shares, shares		1,039
Issuance of common stock upon equity financings, net of issuance costs	14,290	$ 1	14,289
Issuance of common stock upon equity financings, net of issuance cost, shares		7,067
Issuance of fully vested options to settle accrued liabilities	1,007		1,007
Stock-based compensation expense from stock options and ESPP shares	2,660		2,660
Net loss	(22,663)				(22,663)
Change in unrealized gain on available-for-sale securities, net of tax	(101)			(101)
Ending balance at Dec. 31, 2015	14,883	$ 12	420,453	(14)	(405,568)
Ending balance, shares at Dec. 31, 2015		121,839
Issuance of common stock upon exercise of stock options and purchases of ESPP shares	410		410
Issuance of common stock upon exercise of stock options and purchases of ESPP shares, shares		413
Issuance of common stock upon equity financings, net of issuance costs	23,745	$ 2	23,743
Issuance of common stock upon equity financings, net of issuance cost, shares		19,045
Issuance of fully vested options to settle accrued liabilities	1,143		1,143
Stock-based compensation expense from stock options and ESPP shares	2,655		2,655
Net loss	(34,509)				(34,509)
Change in unrealized gain on available-for-sale securities, net of tax	11			11
Ending balance at Dec. 31, 2016	8,338	$ 14	448,404	(3)	(440,077)
Ending balance, shares at Dec. 31, 2016		141,297
Issuance of common stock upon exercise of stock options and purchases of ESPP shares	649		649
Issuance of common stock upon exercise of stock options and purchases of ESPP shares, shares		667
Issuance of common stock upon equity financings, net of issuance costs	11,989	$ 1	11,988
Issuance of common stock upon equity financings, net of issuance cost, shares		8,873
Issuance of fully vested options to settle accrued liabilities	1,600		1,600
Stock-based compensation expense from stock options and ESPP shares	2,605		2,605
Net loss	(3,695)				(3,695)
Change in unrealized gain on available-for-sale securities, net of tax	2			2
Ending balance at Dec. 31, 2017	$ 21,488	$ 15	$ 465,246	$ (1)	$ (443,772)
Ending balance, shares at Dec. 31, 2017		150,837

Statement of Stockholders' Equ6

Statement of Stockholders' Equity (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Statement Of Stockholders Equity [Abstract]
Stock issuance costs	$ 374	$ 1,364	$ 491

Statement of Cash Flows

Statement of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Cash flows from operating activities
Net loss	$ (3,695)	$ (34,509)	$ (22,663)
Adjustments to reconcile net loss to net cash used in operating activities:
Sale of intellectual property rights for non-operating purposes	(500)
Depreciation and amortization	437	416	425
Stock-based compensation	2,605	2,655	2,660
Inventory write-down	2,259	687	303
Amortization of debt issuance cost	62	104	100
Loss on debt extinguishment		9
Net accretion/amortization on investments	(41)	(216)	(278)
Realized gain from sale of marketable equity security, net of tax			(117)
Changes in assets and liabilities:
Accounts receivable	(1,222)	1,068	(100)
Inventories	(140)	(552)	(579)
Prepaid expenses and other assets	(1,115)	656	(2,056)
Accounts payable	(566)	800	265
Accrued liabilities	1,594	1,419	1,385
Contract research liability	51	208	217
Deferred revenue	(1,072)	(38)	(395)
Total adjustments	2,352	7,216	1,830
Net cash used in operating activities	(1,343)	(27,293)	(20,833)
Cash flows from investing activities
Sale of intellectual property rights for non-operating purposes	500
Purchases of property and equipment	(69)	(147)	(225)
Purchases of available-for-sale securities	(8,373)	(24,400)	(34,040)
Proceeds from maturities of available-for-sale securities	20,632	30,584	40,619
Proceeds from sales of short-term investment			178
Net cash provided by investing activities	12,690	6,037	6,532
Cash flows from financing activities
Payments on equipment financing obligations	(14)	(19)	(21)
Net proceeds from issuances of common stock upon exercise of stock options, and purchases of ESPP shares	649	410	1,175
Net proceeds from issuances of common stock in connection with equity financings	11,989	23,745	14,290
Payment of additional issuance cost for term loan		(173)	(240)
Payment of final payment for term loan		(886)
Net cash provided by financing activities	12,624	23,077	15,204
Net increase in cash and cash equivalents	23,971	1,821	903
Cash and cash equivalents at beginning of year	5,404	3,583	2,680
Cash and cash equivalents at end of year	29,375	5,404	3,583
Supplemental disclosure of cash flow information
Cash paid for interest	1,703	1,611	1,595
Supplementary disclosure of non-cash financing information
Fully vested options issued to settle accrued liabilities	$ 1,600	$ 1,143	$ 1,007

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2017
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	1. Summary of Significant Accounting Policies Nature of Operations DURECT Corporation (the Company) was incorporated in the state of Delaware on February 6, 1998. The Company is a biopharmaceutical company with research and development programs broadly falling into two categories: (i) new chemical entities derived from our Epigenetics Regulator Program, in which the Company attempts to discover and develop molecules which have not previously been approved and marketed as therapeutics, and (ii) Drug Delivery Programs, in which the Company applies its formulation expertise and technologies largely to active pharmaceutical ingredients whose safety and efficacy have previously been established but which the Company aims to improve in some manner through a new formulation. The Company has several products under development by itself and with third party collaborators. The Company also manufactures and sells osmotic pumps used in laboratory research, and designs, develops and manufactures a wide range of standard and custom biodegradable polymers and excipients for pharmaceutical and medical device clients for use as raw materials in their products. In addition, the Company conducts research and development of pharmaceutical products in collaboration with third party pharmaceutical and biotechnology companies. Basis of Presentation and Use of Estimates The Company’s financial statements have been prepared in accordance with U.S. generally accepted accounting principles (U.S. GAAP). The preparation of the accompanying Financial Statements conforms to accounting principles generally accepted in the U.S. which requires management to make judgments, estimates and assumptions that affect the reported amounts of assets, liabilities, equity, revenues and expenses, and related disclosures. On an ongoing basis, management evaluates its estimates including, but not limited to, those related to revenue recognition, the period of performance, identification of deliverables and evaluation of milestones with respect to our collaborations, the amounts of revenues, recoverability of inventory, certain accrued liabilities including accrued clinical trial liability, and stock-based compensation. The Company bases its estimates on historical experience and on various other market-specific and other relevant assumptions that the Company believe to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities that are not readily apparent from other sources. Actual results could differ materially from those estimates. Liquidity and Need to Raise Additional Capital As of December 31, 2017, the Company has an accumulated deficit of $443.8 million as well as negative cash flows from operating activities. The Company historically has had negative cash flows from operating activities and expects its negative cash flows to continue. The Company will continue to require substantial funds to continue research and development, including clinical trials of its product candidates. Management’s plans in order to meet its operating cash flow requirements include seeking additional collaborative agreements for certain of its programs and achieving milestone and other payments under its collaboration and licensing agreements as well as financing activities such as public offerings and private placements of its common stock, preferred stock offerings, issuances of debt and convertible debt instruments. There are no assurances that such additional funding will be obtained and that the Company will succeed in its future operations. If the Company cannot successfully raise additional capital and implement its strategic development plan, its liquidity, financial condition and business prospects will be materially and adversely affected. Cash, Cash Equivalents and Investments The Company considers all highly liquid investments with maturities of 90 days or less from the date of purchase to be cash equivalents. Investments with original maturities of greater than 90 days from the date of purchase but less than one year from the balance sheet date are classified as short-term investments, while investments with maturities in one year or beyond one year from the balance sheet date are classified as long-term investments. Management determines the appropriate classification of its cash equivalents and investment securities at the time of purchase and re-evaluates such determination as of each balance sheet date. Management has classified the Company’s cash equivalents and investments as available-for-sale securities in the accompanying financial statements. Available-for-sale securities are carried at fair value, with unrealized gains and losses reported as a component of accumulated other comprehensive loss. Realized gains and losses are included in interest income. There were no material realized gains or losses in the periods presented other than the gain realized from sale of a marketable equity security in the year ended December 31, 2015. The cost of securities sold is based on the specific identification method. The Company invests in debt instruments of government agencies, corporations, and money market funds with high credit ratings. The Company has established guidelines regarding diversification of its investments and their maturities with the objectives of maintaining safety and liquidity, while maximizing yield. Concentrations of Credit Risk Financial instruments that potentially subject the Company to credit risk consist principally of interest-bearing investments and trade receivables. The Company maintains cash, cash equivalents and investments with various major financial institutions. The Company performs periodic evaluations of the relative credit standing of these financial institutions. In addition, the Company performs periodic evaluations of the relative credit quality of its investments. Pharmaceutical companies and academic institutions account for a substantial portion of the Company’s trade receivables. The Company provides credit in the normal course of business to its customers and collateral for these receivables is generally not required. The risk associated with this concentration is limited to a certain extent due to the large number of accounts and their geographic dispersion. The Company monitors the creditworthiness of its customers to which it grants credit terms in the normal course of business. The Company maintains reserves for estimated credit losses and, to date, such losses have been immaterial in all periods presented. Customer and Product Line Concentrations A portion of the Company’s revenue is derived from its ALZET mini pump product line, LACTEL biodegradable polymer product line and the sale of certain excipients for REMOXY ER and one excipient that is included in a currently marketed animal health product. In 2017, revenue from the sale of products from the ALZET product line and the LACTEL product line accounted for 14% and 12% of total revenue, respectively. In 2016, revenue from the ALZET product line and the LACTEL product line accounted for 51% and 31% of total revenue, respectively. In 2015, revenue from the ALZET product line and the LACTEL product line accounted for 36% and 22% of total revenue, respectively. In 2017, Sandoz and Indivior accounted for 41% and 25% of the Company’s total revenues. In 2016, Tolmar accounted for 15% of the Company’s total revenues. In 2015, Zogenix and Tolmar accounted for 26% and 11% of the Company’s total revenues. Total revenue by geographic region for the years 2017, 2016 and 2015 are as follows (in thousands): Year ended December 31, 2017 2016 2015 United States $ 11,323 $ 9,082 $ 14,289 Europe 34,261 1,945 1,817 Japan 1,395 1,413 1,897 Others 2,191 1,585 1,121 Total $ 49,170 $ 14,025 $ 19,124 Revenue by geography is determined by the location of the customer. Inventories Inventories are stated at the lower of cost or net realizable value, with cost determined on a first-in, first-out basis. Inventories, in part, include certain excipients that are sold to a customer for a currently marketed animal health product and included in several products in development or awaiting regulatory approval. In October 2017, the Company announced that PERSIST, the Phase 3 clinical trial for POSIMIR, did not meet its primary efficacy endpoint. As a result, the Company wrote down certain lots of inventory which are no longer considered to be probable for use prior to expiration and prepaid inventory related to a minimum purchase agreement for an excipient. In addition, the Company recorded a liability related to a minimum purchase agreement for the same excipient. In 2017, the Company recorded charges to cost of goods sold of approximately $2.0 million, of which approximately $503,000 related to the write-down of the cost basis of inventory on hand, $500,000 related to the prepaid inventory for the minimum purchase commitment for this excipient, and $1.0 million related to the accrual of a liability for the remaining minimum purchase commitment for the same excipient. As of December 31, 2017, the remaining carrying value of the excipient in the Company’s inventory was $69,000. In the event that management determines that the Company will not utilize all of these materials, there could be a potential write-off related to this inventory. If the Company is able to subsequently sell products made with raw materials that were previously written down, the Company will report an unusually high gross profit as there will be no associated cost of goods for these materials. The Company’s inventories consisted of the following (in thousands): December 31, 2017 2016 Raw materials $ 282 $ 745 Work in-process 1,182 1,672 Finished goods 1,699 1,365 Total inventories $ 3,163 $ 3,782 Property and Equipment Property and equipment are stated at cost less accumulated depreciation, which is computed using the straight-line method over the estimated useful lives of the assets, which range from three to five years. Leasehold improvements are amortized using the straight-line method over the estimated useful lives of the assets, or the terms of the related leases, whichever are shorter. Goodwill Goodwill is periodically assessed and evaluated for impairment at the reporting unit level. The Company operates in one operating segment and also has only one reporting unit, which is the research, development and manufacturing of pharmaceutical products. The Company assesses the impairment of goodwill at least annually and whenever events or changes in circumstances indicate that the carrying value may not be recoverable. Factors the Company considers important which could trigger an impairment review include the following: • significant decline in our stock price for a prolonged period; • our market capitalization relative to net book value; • new information affecting the commercial value of the asset; • significant underperformance relative to expected historical or projected future operating results; • significant changes in the manner of our use of the acquired assets or the strategy for the Company’s overall business; and • significant negative industry or economic trends. As of December 31, 2017, the carrying value of goodwill was approximately $6.4 million and no impairment of goodwill has been recorded for any of the periods presented. The Company evaluates goodwill for impairment at least annually. In 2017, 2016 and 2015, goodwill was evaluated and no indicators of impairment were identified. Should goodwill become impaired, the Company may be required to record an impairment charge. To date, the Company has not recorded any impairment charge related to goodwill. Impairment of Long-Lived Assets The Company reviews long-lived assets, including property and equipment, intangible assets, and other long-term assets, for impairment whenever events or changes in business circumstances indicate that the carrying amount of the assets may not be fully recoverable. An impairment loss would be recognized when estimated undiscounted future cash flows expected to result from the use of the asset and its eventual disposition is less than its carrying amount. Impairment, if any, is calculated as the amount by which an asset’s carrying value exceeds its fair value, typically using discounted cash flows to determine fair value. Through December 31, 2017, there have been no material impairment losses. Stock-Based Compensation The Company accounts for share-based payments using a fair-value based method for costs related to all share-based payments, including stock options and stock issued under the Company’s employee stock purchase plan (ESPP). The Company estimates the fair value of share-based payment awards on the date of grant using an option-pricing model. See Note 9 for further information regarding stock-based compensation. Revenue Recognition Revenue from the sale of products is recognized when there is persuasive evidence that an arrangement exists, the product is shipped and title transfers to customers, provided no continuing obligation on the Company’s part exists, the price is fixed or determinable and the collectability of the amounts owed is reasonably assured. The Company enters into license and collaboration agreements under which it may receive upfront license fees, research funding and contingent milestone payments and royalties. The Company’s deliverables under these arrangements typically consist of granting licenses to intellectual property rights and providing research and development services. For multiple-element arrangements, each deliverable within a multiple deliverable revenue arrangement is accounted for as a separate unit of accounting if both of the following criteria are met: (1) the delivered item or items have value to the customer on a standalone basis and (2) for an arrangement that includes a general right of return relative to the delivered item(s), delivery or performance of the undelivered item(s) is considered probable and substantially in the Company’s control. The accounting standards contain a presumption that separate contracts entered into at or near the same time with the same entity or related parties were negotiated as a package and should be evaluated as a single agreement. Deferred revenue associated with a non-refundable payment received under a license and collaboration agreement for which the performance obligations are terminated will result in an immediate recognition of any remaining deferred revenue in the period that termination occurred provided that all performance obligations have been satisfied. From time-to-time, the Company also enters into sales of intellectual property rights under which it may receive upfront payments, contingent milestone payments and earn-outs from third party collaborators. The Company’s deliverable under these arrangements typically consists of sale of intellectual property rights, and does not contain any substantive continuing obligations subsequent to the transfer of the related rights, title, and interest to the buyer. The Company recognizes the upfront payment as revenue because such arrangement constitutes the Company's revenue-earning activities and is in line with its ordinary course of ongoing business operations. Research and development revenue related to services performed under the collaborative arrangements with the Company’s third-party collaborators is recognized as the related research and development services are performed. These research payments received under each respective agreement are not refundable and are generally based on reimbursement of qualified expenses, as defined in the agreements. Research and development expenses under the collaborative research and development agreements generally approximate or exceed the revenue recognized under such agreements over the term of the respective agreements. Deferred revenue may result when the Company does not expend the required level of effort during a specific period in comparison to funds received under the respective agreement. Milestone payments under collaborative arrangements are triggered either by the results of the Company’s research and development efforts or by specified sales results by a third-party collaborator. Milestones related to the Company’s development-based activities may include initiation of various phases of clinical trials, successful completion of a phase of development or results from a clinical trial, acceptance of a New Drug Application by the FDA or an equivalent filing with an equivalent regulatory agency in another territory, or regulatory approval by the FDA or by an equivalent regulatory agency in another territory. Due to the uncertainty involved in meeting these development-based milestones, the development-based milestones are considered to be substantive (i.e., not just achieved through passage of time) at the inception of the collaboration agreement. In addition, the amounts of the payments assigned thereto are considered to be commensurate with the enhancement of the value of the delivered intellectual property as a result of the Company’s performance. The Company’s involvement is generally necessary to the achievement of development-based milestones. The Company would account for development-based milestones as revenue upon achievement of the substantive milestone events. Milestones related to sales-based activities may be triggered upon events such as the first commercial sale of a product or when sales first achieve a defined level. Under the Company’s collaborative agreements, the Company’s third-party collaborators will take the lead in commercialization activities and the Company is typically not involved in the achievement of sales-based milestones. These sales-based milestones would be achieved after the completion of the Company’s development activities. The Company would account for the sales-based milestones in the same manner as royalties, with revenue recognized upon achievement of the milestone. In addition, upon the achievement of either development-based or sales-based milestone events, the Company has no future performance obligations related to any milestone payments. Research and Development Expenses Research and development expenses are primarily comprised of salaries and benefits associated with research and development personnel, overhead and facility costs, preclinical and non-clinical development costs, clinical trial and related clinical manufacturing costs, contract services, and other outside costs. Research and development costs are expensed as incurred. Research and development costs paid to third parties under sponsored research agreements are recognized as the related services are performed. In addition, reimbursements of research and development expenses incurred by the Company’s partners are recorded as collaborative research and development revenue. Comprehensive Income (Loss) Components of other comprehensive income (loss) are comprised entirely of unrealized gains and losses on the Company’s available-for-sale securities for all periods presented. Total comprehensive loss has been disclosed in the Company’s Statements of Comprehensive Loss. Segment Reporting The Company operates in one operating segment, which is the research, development and manufacturing of pharmaceutical products. Net Loss Per Share Basic net loss per share is calculated by dividing the net loss by the weighted-average number of common shares outstanding. Diluted net loss per share is computed using the weighted-average number of common shares outstanding and common stock equivalents (i.e., options to purchase common stock) outstanding during the period, if dilutive, using the treasury stock method for options. The numerators and denominators in the calculation of basic and diluted net loss per share were as follows (in thousands except per share amounts): Year Ended December 31, 2017 2016 2015 Numerators: Net loss $ (3,695 ) $ (34,509 ) $ (22,663 ) Denominators: Weighted average shares used to compute basic net loss per share 145,273 133,163 118,523 Effect of dilutive securities: Dilution from stock options — — — Dilution from ESPP — — — Dilutive common shares — — — Weighted average shares used to compute diluted net loss per share 145,273 133,163 118,523 Net loss per share: Basic $ (0.03 ) $ (0.26 ) $ (0.19 ) Diluted $ (0.03 ) $ (0.26 ) $ (0.19 ) The computation of diluted net loss per share for the years ended December 31, 2017, 2016 and 2015 excludes the impact of options to purchase 20.1 million, 18.7 million and 16.5 million shares of common stock outstanding, respectively, at December 31, 2017, 2016 and 2015, as such impact would be antidilutive. Shipping and Handling Costs related to shipping and handling are included in cost of revenues for all periods presented. Operating Leases The Company leases administrative, manufacturing and laboratory facilities under operating leases. Lease agreements may include rent holidays, rent escalation clauses and tenant improvement allowances. The Company recognizes scheduled rent increases on a straight-line basis over the lease term beginning with the date the Company takes possession of the leased space. The Company records tenant improvement allowances as deferred rent liabilities and amortizes the deferred rent over the terms of the lease to rent expense on the statements of operations and comprehensive loss. Recent Accounting Pronouncements In May 2014, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update 2014-09, Revenue from Contracts with Customers (ASU 2014-09), which amends the guidance in former ASC 605, Revenue Recognition. The core principle of the guidance is that an entity should recognize revenue when it transfers promised goods or services to customers in an amount that reflects the consideration to which the company expects to be entitled in exchange for those goods or services. The guidance provides companies with two implementation methods. Companies can choose to apply the standard retrospectively to each prior reporting period presented (full retrospective application) or retrospectively with the cumulative effect of initially applying the standard as an adjustment to the opening balance of retained earnings of the annual reporting period that includes the date of initial application (modified retrospective application). The standard will be effective for the Company in the first quarter of 2018. To date, the Company’s revenues have been derived from product sales, license and collaboration agreements, and sale of intellectual property rights. Based on the Company’s analysis, it does not currently anticipate a material quantitative impact on product revenue as the timing of revenue recognition for product sales is not expected to change as product revenue will continue to be recognized when control of the goods is transferred to the customer. For the Company’s license and collaboration agreements, the consideration the Company is eligible to receive under these agreements typically consists of upfront payments, research and development funding, milestone payments, and royalties. For the Company’s agreements related to sale of intellectual property rights, the consideration the Company is eligible to receive under these agreements typically consists of upfront payments, milestone payments, and earn-outs. The Company has substantially completed its review of the impact that this new standard will have on its collaboration and license arrangements and intellectual property purchase agreements as well as on its financial statement disclosures. The Company will select the modified retrospective method to adopt the standard effective the first quarter of 2018. The Company expects that the impact of adopting the new standard will not be material. The Company does not expect a material cumulative-effect adjustment to accumulated deficit on January 1, 2018 upon adoption of the new standard. The new standard requires more robust disclosures than required by previous guidance, including disclosures related to disaggregation of revenue into appropriate categories, performance obligations, the judgments made in revenue recognition determinations, adjustments to revenue which relate to activities from previous quarters or years, any significant reversals of revenue, and costs to obtain or fulfill contracts. In February 2016, the Financial Accounting Standards Board (FASB) issued ASU No. 2016-02, Leases (Topic 842), which amends the existing accounting standards for leases. The new standard requires lessees to record a right-of-use asset and a corresponding lease liability on the balance sheet (with the exception of short-term leases). For lessees, leases will continue to be classified as either operating or financing in the income statement. This ASU becomes effective for the Company in the first quarter of fiscal year 2019 and early adoption is permitted. This ASU is required to be applied with a modified retrospective approach and requires application of the new standard at the beginning of the earliest comparative period presented. The Company is currently evaluating the impact that ASU 2016-02 will have on its financial statements.

Strategic Agreements

Strategic Agreements	12 Months Ended
	Dec. 31, 2017
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Strategic Agreements	2. Strategic Agreements The collaborative research and development and other revenues associated with the Company’s major third-party collaborators are as follows (in thousands): Year ended December 31, 2017 2016 2015 Collaborator Sandoz AG (Sandoz) (1) $ 20,000 $ — $ — Zogenix, Inc. (Zogenix) (2) 835 555 4,898 Santen Pharmaceutical Co. Ltd. (Santen) (3) 294 514 824 Pain Therapeutics, Inc. (Pain Therapeutics) 109 670 1,385 Others 2,339 141 725 Total collaborative research and development and other revenue $ 23,577 $ 1,880 $ 7,832 (1) Amounts related to ratable recognition of upfront fees were $20.0 million in 2017 and zero in 2016 and 2015; the Company and Sandoz signed a license agreement effective June 2017. As of December 31, 2017, all of the $20.0 million upfront fee had been recognized as revenue as the Company’s contractual performance obligations had been fulfilled. (2) Amounts related to ratable recognition of upfront fees were $833,000 in 2017, $208,000 in 2016 and $255,000 in 2015, respectively. The Company and Zogenix signed a license agreement effective July 2011. In August 2017, the Company and Zogenix terminated the license agreement. As a result, the Company recognized as revenue all of the remaining upfront fees in the twelve months ended December 31, 2017 that had previously been deferred. (3) Amounts related to recognition of upfront fees were $199,000 in 2017, $228,000 in 2016 and $274,000 in 2015, respectively. The Company and Santen signed a license agreement effective December 2014. As of March 2, 2018, the Company had potential milestones of up to $337.5 million that the Company may receive in the future under its collaborative arrangements, of which $44.5 million are development-based milestones and $293.0 million are sales-based milestones. Within the category of development-based milestones, $2.0 million are related to early stage clinical testing (defined as Phase 1 or 2 activities), $3.0 million are related to late stage clinical testing (defined as Phase 3 activities), $8.0 million are related to regulatory filings, and $31.5 million are related to regulatory approvals. No payments were received between December 31, 2017 and March 2, 2018. Agreement with Sandoz AG. In May 2017, the Company and Sandoz AG (“Sandoz”) entered into a license agreement to develop and market POSIMIR in the United States. Following expiration of the applicable waiting period under the Hart-Scott-Rodino Antitrust Improvements Act of 1976 (HSR), the agreement became effective in June 2017. POSIMIR is the Company’s investigational post-operative pain relief depot that utilizes the Company’s patented SABER technology to deliver bupivacaine to provide up to three days of pain relief after surgery. The Company retains commercialization rights in the rest of the world. Under terms of the agreement, Sandoz made an upfront payment of $20 million, with the potential for up to an additional $43 million in milestone payments based on successful development and regulatory milestones (of which $30 million is currently feasible), and up to an additional $230 million in sales-based milestones. DURECT was responsible for the completion of the ongoing PERSIST Phase 3 clinical trial for POSIMIR as well as FDA interactions through potential approval. If approved, DURECT also has certain manufacturing obligations under this agreement. Sandoz will have exclusive commercialization rights in the United States upon regulatory approval with sole funding responsibility for commercialization activities. Sandoz will pay the Company a tiered double-digit royalty on product sales for a defined period, after which the license granted to Sandoz shall convert to a non-exclusive, fully paid, royalty-free, irrevocable and perpetual license. The term of the agreement shall be for the duration of Sandoz’s obligation to pay royalties for product sales under the Agreement. The agreement provides each party with specified termination rights, including the right of Sandoz to terminate at will after a specified period and each party to terminate the agreement upon material breach of the agreement by the other party. The failure of the PERSIST trial for POSIMIR to achieve its primary endpoint gives Sandoz a right to terminate our agreement with them on thirty days’ notice, in addition to the rights they have to terminate for convenience on six months’ notice. The Company evaluated the agreement under the accounting guidance for multiple element arrangements and identified three deliverables: the license to develop and market POSIMIR, the research and development services and the manufacturing services. Given that the delivery of the manufacturing services by the Company is dependent upon approval of POSIMIR by the FDA, and that the fee to be received by the Company for these services, should they be delivered, is consistent with their estimated selling price, the Company considers the manufacturing services to be a contingent deliverable and has excluded them from the initial measurement and allocation of the arrangement consideration. The Company evaluated the license deliverable and concluded that it did not have stand alone value separate from the research and development services and accordingly combined these deliverables into a single unit of accounting. The Company allocated the arrangement consideration, which consists of the $20.0 million upfront payment, to this single unit of accounting. As of December 31, 2017, all of the $20.0 million upfront fee had been recognized as revenue as the Company’s contractual performance obligations had been fulfilled. The effect of a change made to the estimated performance period, and the related ratably recognized revenue, would occur on a prospective basis in the period that the change was made. The Company considers the development and regulatory milestones to be substantive, and will recognize the associated milestone payments as revenue when the underlying milestone events are achieved. Total collaborative research and development revenue recognized by the Company for Sandoz was $20.0 million for 2017, compared with zero for 2016 and 2015. The cumulative aggregate payments received by the Company from Sandoz as of December 31, 2017 were $20.0 million under this agreement. Patent Purchase Agreement with Indivior On September 26, 2017, the Company entered into a Patent Purchase Agreement (the “Agreement”) with Indivior UK Limited (“Indivior”). Pursuant to the Agreement, the Company has assigned to Indivior certain patents that may provide further intellectual property protection for RBP-7000, Indivior’s investigational once-monthly injectable risperidone product for the treatment of schizophrenia. In consideration for such assignment, Indivior has made an upfront non-refundable payment to DURECT of $12.5 million, and has also agreed to make an additional $5.0 million payment to DURECT contingent upon the achievement of a regulatory milestone, as well as quarterly earn-out payments that are based on a single digit percentage of U.S. net sales for certain products covered by the assigned patent rights, including RBP-7000. The assigned patent rights include granted patents extending through at least 2026. DURECT also receives a non-exclusive right under the assigned patents to develop and commercialize certain risperidone-containing products and products that do not contain risperidone or buprenorphine. The agreement contains customary representations, warranties and indemnities of the parties. The Company received the payment of $12.5 million from Indivior in September 2017 and recognized the $12.5 million as revenue from sale of intellectual property rights in 2017 as the Company does not have any continuing obligations under the purchase agreement. Agreement with Pain Therapeutics, Inc. In December 2002, the Company entered into an exclusive agreement with Pain Therapeutics, Inc. (Pain Therapeutics) to develop and commercialize on a worldwide basis REMOXY ER and other oral sustained release, abuse deterrent opioid products incorporating four specified opioid drugs, using the ORADUR technology. This agreement currently covers only REMOXY ER. Under the terms of this agreement, Pain Therapeutics paid the Company an upfront license fee of $1.0 million, with the potential for an additional $3.0 million in performance milestone payments based on the successful development and approval of REMOXY ER. Of these potential milestones, all $3.0 million are development-based milestones. There are no sales-based milestones under the agreement. As of December 31, 2017, the Company had received $1.5 million in cumulative milestone payments. In March 2016, Pain Therapeutics resubmitted a New Drug Application (NDA) to the U.S. Food and Drug Administration (FDA), and in September 2016, Pain Therapeutics received a Complete Response Letter from the FDA for REMOXY ER. Based on its review, the FDA has determined that the NDA cannot be approved in its present form and specifies additional actions and data that are needed for drug approval. In February 2018, Pain Therapeutics stated that they had resubmitted the REMOXY ER NDA. In March 2018, Pain Therapeutics announced that the NDA had been accepted by the FDA and that the FDA has set a PDUFA target action date of August 7, 2018. Total collaborative research and development revenue recognized under the agreements with Pain Therapeutics was $109,000 in 2017, $670,000 in 2016 and $1.4 million in 2015. In May 2015, Pain Therapeutics sent a letter to the Company that provided the Company with formal written notice that Pain Therapeutics was deleting, effective as of January 12, 2015, the opioid drug hydrocodone (and only hydrocodone) as a licensed product under the agreement. The letter did not alter the terms of the agreement regarding the remaining three licensed products (REMOXY ER, hydromorphone or oxymorphone) or otherwise amend the agreement. In December 2016, Pain Therapeutics returned to the Company all of Pain Therapeutics’ rights and was relieved of its obligations under the Company’s license agreement to develop and commercialize ORADUR-based formulations of hydromorphone and oxymorphone but without impacting the rights and obligations of the two parties with respect to REMOXY ER. The cumulative aggregate payments received by the Company from Pain Therapeutics as of December 31, 2017 were $40.4 million under this agreement. The Company recognized no product revenue related to key excipients for REMOXY ER for 2017 compared to $653,000 for 2016 and $96,000 for 2015. The associated cost of goods sold were zero for 2017, compared to $216,000 for 2016 and $51,000 for 2015. Recent orders for these excipients from Pain Therapeutics have been processed through mutually agreeable purchase orders, in the absence of an existing long-term contract. Pursuant to the Company’s 2002 agreement with Pain Therapeutics, the Company is to be the exclusive supplier of certain defined excipients for products in the collaboration. Agreement with Zogenix, Inc. On July 11, 2011, the Company and Zogenix, Inc. (Zogenix) entered into a Development and License Agreement (the Zogenix Agreement). The Company and Zogenix had previously been working together under a feasibility agreement pursuant to which the Company’s research and development costs were reimbursed by Zogenix. Under the Zogenix Agreement, Zogenix was responsible for the clinical development and commercialization of a proprietary, long-acting injectable formulation of risperidone using the Company’s SABER controlled-release formulation technology potentially in combination with Zogenix’s DosePro® needle-free, subcutaneous drug delivery system. DURECT was responsible for non-clinical, formulation and CMC development activities. The Company was to be reimbursed by Zogenix for its research and development efforts on the product. Zogenix paid a non-refundable upfront fee to the Company of $2.25 million in July 2011. The Company’s research and development services were considered integral to utilizing the licensed intellectual property and, accordingly, the deliverable were accounted for as a single unit of accounting. The $2.25 million upfront fee had been recognized as collaborative research and development revenue ratably over the term of the Company’s research and development involvement with Zogenix with respect to this product candidate. The Company granted to Zogenix an exclusive worldwide license, with sub-license rights, to the Company’s intellectual property rights related to the Company’s proprietary polymeric and non-polymeric controlled-release formulation technology to make and have made, use, offer for sale, sell and import risperidone products, where risperidone is the sole active agent, for administration by injection in the treatment of schizophrenia, bipolar disorder or other psychiatric related disorders in humans. The Company retained the right to supply Zogenix’s Phase 3 clinical trial and commercial product requirements on the terms set forth in the Zogenix Agreement. Zogenix was permitted to terminate the Zogenix Agreement without cause at any time upon prior written notice, and either party was permitted to terminate the Zogenix Agreement upon certain circumstances including written notice of a material uncured breach. In August 2017, the Company and Zogenix terminated the Zogenix Agreement. Under the mutual termination agreement, Zogenix’s development and commercialization rights were returned to the Company, and Zogenix will transfer to the Company all regulatory filings and development information related to Relday. As a result of the termination of the Zogenix agreement, the Company recognized revenue during the third quarter of 2017 for the remaining $750,000 of deferred revenue related to the upfront fee as the Company had no remaining performance obligations under the agreement; this recognition of revenue did not result in additional cash proceeds to the Company. The following table provides a summary of collaborative research and development revenue recognized under the agreements with Zogenix (in thousands). The cumulative aggregate payments received by the Company as of December 31, 2017 were $20.1 million under these agreements. Year Ended December 31, 2017 2016 2015 Ratable recognition of upfront payment $ 833 $ 208 $ 255 Research and development expenses reimbursable by Zogenix 2 347 4,643 Total collaborative research and development revenue $ 835 $ 555 $ 4,898 Agreement with Santen Pharmaceutical Co., Ltd. On December 11, 2014, the Company and Santen Pharmaceutical Co., Ltd. (Santen) entered into a definitive agreement (the Santen Agreement). Pursuant to the Santen Agreement, the Company granted Santen an exclusive worldwide license to the Company’s proprietary SABER formulation platform and other intellectual property to develop and commercialize a sustained release product utilizing the Company’s SABER technology to deliver an ophthalmology drug. Santen controls and funds the development and commercialization program, and the parties established a joint management committee to oversee, review and coordinate the development activities of the parties under the Santen Agreement. In connection with the Santen agreement, Santen agreed to pay the Company an upfront fee of $2.0 million in cash and to make contingent cash payments to the Company of up to $76.0 million upon the achievement of certain milestones, of which $13.0 million are development-based milestones and $63.0 million are commercialization-based milestones including milestones requiring the achievement of certain product sales targets (none of which has been achieved as of December 31, 2017). Santen will also pay for certain Company costs incurred in the development of the licensed product. If the product is commercialized, the Company would also receive a tiered royalty on annual net product sales ranging from single-digit to the low double digits, determined on a country-by-country basis. As of December 31, 2017, the cumulative aggregate payments received by the Company under this agreement were $3.3 million. The following table provides a summary of collaborative research and development revenue recognized under the Santen Agreement (in thousands). Year Ended December 31, 2017 2016 2015 Ratable recognition of upfront payment $ 199 $ 228 $ 274 Research and development expenses reimbursable by Santen 95 286 550 Total collaborative research and development revenue $ 294 $ 514 $ 824

Financial Instruments

Financial Instruments	12 Months Ended
	Dec. 31, 2017
Fair Value Disclosures [Abstract]
Financial Instruments	3. Financial Instruments Fair value is defined as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. The Company’s valuation techniques used to measure fair value maximize the use of observable inputs and minimize the use of unobservable inputs. The Company follows a fair value hierarchy based on three levels of inputs, of which the first two are considered observable and the last unobservable, that may be used to measure fair value. These levels of inputs are the following: • Level 1—Quoted prices in active markets for identical assets or liabilities. • Level 2—Inputs other than Level 1 that are observable, either directly or indirectly, such as quoted prices for similar assets or liabilities; quoted prices in markets that are not active; or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities. • Level 3—Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities. The Company’s financial instruments are valued using quoted prices in active markets or based upon other observable inputs. The following table sets forth the fair value of the Company’s financial assets that were measured at fair value on a recurring basis as of December 31, 2017 (in thousands): Level 1 Level 2 Level 3 Total Money market funds $ 568 $ — $ — $ 568 Certificates of deposit — 150 — 150 Commercial paper — 33,307 — 33,307 Corporate debt — 1,297 — 1,297 Total $ 568 $ 34,754 — $ 35,322 The following table sets forth the fair value of our financial assets that were measured at fair value on a recurring basis as of December 31, 2016 (in thousands): Level 1 Level 2 Level 3 Total Money market funds $ 693 $ — $ — $ 693 Certificates of deposit — 150 — 150 Commercial paper — 4,947 — 4,947 Corporate debt — 2,643 — 2,643 U.S. Government agencies — 14,459 — 14,459 Total $ 693 $ 22,199 $ — $ 22,892 The Company’s financial instruments are valued using quoted prices in active markets or based upon other observable inputs. Money market funds are classified as Level 1 financial assets. Certificates of deposit, commercial paper, corporate debt securities, and U.S. Government agency securities are classified as Level 2 financial assets. The fair value of the Level 2 assets is estimated using pricing models using current observable market information for similar securities. The Company’s Level 2 investments include U.S. government-backed securities and corporate securities that are valued based upon observable inputs that may include benchmark yields, reported trades, broker/dealer quotes, issuer spreads, two-sided markets, benchmark securities, bids, offers and reference data including market research publications. The fair value of commercial paper is based upon the time to maturity and discounted using the three-month treasury bill rate. The average remaining maturity of the Company’s Level 2 investments as of December 31, 2017 is less than twelve months and these investments are rated by S&P and Moody’s at AAA or AA- for securities and A1 or P1 for commercial paper. The following is a summary of available-for-sale securities as of December 31, 2017 and 2016 (in thousands): December 31, 2017 Amortized Cost Unrealized Gain Unrealized Loss Estimated Fair Value Money market funds $ 568 $ — $ — $ 568 Certificates of deposit 150 — — 150 Commercial paper 33,307 — — 33,307 Corporate debt 1,298 — (1 ) 1,297 $ 35,323 $ — $ (1 ) $ 35,322 Reported as: Cash and cash equivalents $ 27,788 $ — $ — $ 27,788 Short-term investments 7,385 — (1 ) 7,384 Long-term restricted investments 150 — — 150 $ 35,323 $ — $ (1 ) $ 35,322 December 31, 2016 Amortized Cost Unrealized Gain Unrealized Loss Estimated Fair Value Money market funds $ 693 $ — $ — $ 693 Certificates of deposit 150 — — 150 Commercial paper 4,947 — — 4,947 Corporate debt 2,644 — (1 ) 2,643 U.S. Government agencies 14,461 1 (3 ) 14,459 $ 22,895 $ 1 $ (4 ) $ 22,892 Reported as: Cash and cash equivalents $ 3,142 $ — $ — $ 3,142 Short-term investments 19,603 1 (4 ) 19,600 Long-term restricted investments 150 — — 150 $ 22,895 $ 1 $ (4 ) $ 22,892 The following is a summary of the cost and estimated fair value of available-for-sale securities at December 31, 2017, by contractual maturity (in thousands): December 31, 2017 Amortized Cost Estimated Fair Value Mature in one year or less $ 34,755 $ 34,754 $ 34,755 $ 34,754 There were no securities that have had an unrealized loss for more than 12 months as of December 31, 2017. As of December 31, 2017, unrealized losses on available-for-sale investments are not attributed to credit risk and are considered to be temporary. The Company believes that it is more-likely-than-not that investments in an unrealized loss position will be held until maturity or the recovery of the cost basis of the investment. To date, the Company has not recorded any impairment charges on marketable securities related to other-than-temporary declines in market value.

Property and Equipment

Property and Equipment	12 Months Ended
	Dec. 31, 2017
Property Plant And Equipment [Abstract]
Property and Equipment	4. Property and Equipment Property and equipment consist of the following (in thousands): December 31, 2017 2016 Equipment $ 12,688 $ 12,633 Leasehold improvement 9,929 10,007 Construction-in-progress 119 33 22,736 22,673 Less accumulated depreciation and amortization (21,807 ) (21,376 ) Property and equipment, net $ 929 $ 1,297 Depreciation expense was $437,000, $416,000 and $425,000 in 2017, 2016 and 2015, respectively. Amortization expense was zero in 2017 and 2016, and $1,000 in 2015 for assets held under capital leases, respectively. As of December 31, 2017, the Company has recorded $611,000 as a liability which was included in other long-term liabilities on its balance sheet for asset retirement obligations associated with the estimated restoration cost for its leased buildings.

Restricted Investments

Restricted Investments	12 Months Ended
	Dec. 31, 2017
Text Block [Abstract]
Restricted Investments	5. Restricted Investments As of December 31, 2017 and 2016, the Company had $150,000 recorded as restricted investments, which primarily served as collateral for letters of credit securing its leased facility in California.

Commitments

Commitments	12 Months Ended
	Dec. 31, 2017
Commitments And Contingencies Disclosure [Abstract]
Commitments	6. Commitments Operating Leases The Company has lease arrangements for its facilities in California and Alabama as follows. Location Approximate Square Feet Operation Expiration Cupertino, CA 30,000 sq. ft. Office, Laboratory and Manufacturing Lease expires 2019 (with an option to renew for an additional five years) Cupertino, CA 20,000 sq. ft. Office and Laboratory Lease expires 2019 (with an option to renew for an additional five years) Vacaville, CA 24,634 sq. ft. Manufacturing Lease expires 2018 Birmingham, AL 21,540 sq. ft. Office, Laboratory and Manufacturing Lease expires 2021 (with two options to renew the lease term for an additional five years each after the current lease expires) Under these leases, the Company is required to pay certain maintenance expenses in addition to monthly rent. Rent expense is recognized on a straight-line basis over the lease term for leases that have scheduled rental payment increases. Rent expense under all operating leases was $1.9 million for the years ended December 31, 2017, 2016 and 2015, respectively. Future minimum payments under these noncancelable leases are as follows (in thousands): Year ending December 31, Operating Leases 2018 $ 1,948 2019 539 2020 324 2021 193 $ 3,004 Other Purchase Commitments In 2005, the Company entered into a supply agreement with a vendor. The remaining minimum purchase commitment under this agreement is $500,000 in 2018, which has been recorded as an accrued liability on the Company’s Balance Sheet at December 31, 2017, and which was charged to cost of goods sold in the Company’s Statements of Operations and Comprehensive Loss in 2017.

Term Loan

Term Loan	12 Months Ended
	Dec. 31, 2017
Debt Disclosure [Abstract]
Term Loan	7. Term Loan On June 26, 2014, the Company entered into a Loan and Security Agreement (2014 Loan Agreement) with Oxford Finance LLC, pursuant to which Oxford Finance provided a $20 million secured single-draw term loan to the Company with a maturity date of July 1, 2018. The term loan was fully drawn at close and the proceeds are to be used for working capital and general business requirements. The term loan repayment schedule provided for interest only payments for the first 18 months, followed by consecutive equal monthly payments of principal and interest in arrears starting on February 1, 2016 and continuing through the maturity date. The 2014 Loan Agreement provided for a 7.95% interest rate on the term loan, a $150,000 facility fee that was paid at closing and an additional payment equal to 8% of the principal amount of the term loan, which is due when the term loan becomes due or upon the prepayment of the facility. If the Company elects to prepay the loan, there is also a prepayment fee between 1% and 3% of the principal amount of the term loan depending on the timing and circumstances of prepayment. In connection with the term loan, the Company received proceeds of $19.8 million, net of debt offering/issuance costs. The debt offering/issuance costs had been recorded as debt discount on the Company’s balance sheet which together with the final $1.6 million payment and fixed interest rate payments was being amortized to interest expense throughout the life of the term loan using the effective interest rate method. In July 2015, the Company and Oxford Finance entered into the First Amendment of the 2014 Loan Agreement and modified the terms of the 2014 Loan Agreement to change the maturity date from July 1, 2018 to July 1, 2019 and to change the first principal payment date from February 1, 2016 to February 1, 2017. The interest rate remained unchanged, the Company paid a loan modification fee of $240,000 and the additional payment originally equal to 8% of the principal amount of the term loan, which was due when the term loan becomes due or upon the prepayment of the facility, was increased to 10%. Consistent with the accounting treatment noted above for the final payment, the loan modification fee has been recorded on the balance sheet as a debt discount and was being amortized to interest expense over the remaining life of the term loan using the effective interest method. In July 2016, the Company renegotiated the terms of its $20.0 million secured single-draw term loan with Oxford Finance LLC (Oxford Finance) with such renegotiated terms being formalized in a new Loan and Security Agreement (2016 Loan Agreement). The 2016 Loan Agreement supersedes the 2014 Loan Agreement with Oxford Finance and the 2015 amendment to such agreement. The 2016 Loan Agreement provides for interest only payments for the first 18 months, followed by consecutive monthly payments of principal and interest in arrears starting on March 1, 2018 and continuing through the maturity date of the term loan of August 1, 2020. The 2016 Loan Agreement also provides for a floating interest rate (7.95% initially and 8.87% as of December 31, 2017) based on an index rate plus a spread, a $150,000 facility fee that was paid at closing and an additional payment equal to 9.25% of the principal amount of the term loan, which is due when the term loan becomes due or upon the prepayment of the facility. If the Company elects to prepay the loan, there is also a prepayment fee between 1% and 3% of the principal amount of the term loan depending on the timing of prepayment. The facility fee and other debt offering/issuance costs have been recorded as debt discount on the Company’s balance sheet and together with the final $1.9 million payment are being amortized to interest expense during the life of the term loan using the effective interest rate method. The term loan is secured by substantially all of the assets of the Company, except that the collateral does not include any intellectual property (including licensing, collaboration and similar agreements relating thereto), and certain other excluded assets. The 2016 Loan Agreement contains customary representations, warranties and covenants by the Company, which covenants limit the Company’s ability to convey, sell, lease, transfer, assign or otherwise dispose of certain assets of the Company; engage in any business other than the businesses currently engaged in by the Company or reasonably related thereto; liquidate or dissolve; make certain management changes; undergo certain change of control events; create, incur, assume, or be liable with respect to certain indebtedness; grant certain liens; pay dividends and make certain other restricted payments; make certain investments; and make payments on any subordinated debt. The 2016 Loan Agreement also contains customary indemnification obligations and customary events of default, including, among other things, the Company’s failure to fulfill certain obligations of the Company under the 2016 Loan Agreement and the occurrence of a material adverse change which is defined as a material adverse change in the Company’s business, operations, or condition (financial or otherwise), a material impairment of the prospect of repayment of any portion of the loan, or a material impairment in the perfection or priority of lender’s lien in the collateral or in the value of such collateral. In the event of default by the Company under the 2016 Loan Agreement, the lender would be entitled to exercise its remedies thereunder, including the right to accelerate the debt, upon which the Company may be required to repay all amounts then outstanding under the 2016 Loan Agreement, which could harm the Company’s financial condition. The conditionally exercisable call option related to the event of default is considered to be an embedded derivative which is required to be bifurcated and accounted for as a separate financial instrument. In the periods presented, the value of the embedded derivative is not material, but could become material in future periods if an event of default became more probable than is currently estimated. As of December 31, 2017, the Company was in compliance with all material covenants under the Loan Agreement and there had been no material adverse change. In accordance with ASC 470-10-45-2, the term loan had been classified as a current liability on the Company’s balance sheet as of December 31, 2016 due to recurring losses, liquidity concerns and a subjective acceleration clause in the Company’s 2016 Loan Agreement. The Company has sufficient resources to meet its plans for the next twelve months following the issuance of these financial statements and as a result, that portion of the term loan that is due more than 12 months after December 31, 2017 has been classified within non-current liabilities. The fair value of the term loan approximates the carrying value. Future maturities and interest payments under the term loan as of December 31, 2017, are as follows (in thousands): 2018 $ 8,698 2019 8,724 2020 6,642 Total minimum payments 24,064 Less amount representing interest (4,064 ) Gross balance of term loan 20,000 Less unamortized debt discount (85 ) Carrying value of term loan 19,915 Less term loan, current portion, net (7,281 ) Term loan, non-current portion, net $ 12,634 In February 2018, the Company and Oxford Finance entered into a First Amendment of the Loan Agreement (see Note 11. Subsequent Events).

Stockholders' Equity

Stockholders' Equity	12 Months Ended
	Dec. 31, 2017
Equity [Abstract]
Stockholders' Equity	8. Stockholders’ Equity Common Stock In November 2015, the Company filed a shelf registration statement on Form S-3 with the SEC, which upon being declared effective in November 2015, terminated the December 2013 registration statement and allowed the Company to offer up to $125.0 million of securities from time to time in one or more public offerings of its common stock. In addition, the Company entered into a Controlled Equity Offering sales agreement with Cantor Fitzgerald, under which the Company may sell, subject to certain limitations, up to $40 million of common stock through Cantor Fitzgerald, acting as agent. In 2015, the Company raised net proceeds (net of commissions) of approximately $14.3 million from the sale of approximately 7.1 million shares of its common stock in the open market through the Controlled Equity Offering program with Cantor Fitzgerald at a weighted average price of $2.09 per share. In 2016, the Company raised net proceeds of approximately $16.1 million (after deducting underwriting discounts and commissions and offering expense) through the sale of approximately 13.8 million shares of its common stock in an underwritten public offering at a price to the public of $1.25 per share and raised net proceeds (net of commissions) of approximately $7.6 million from the sale of approximately 5.2 million shares of its common stock in the open market through the Controlled Equity Offering program with Cantor Fitzgerald at a weighted average price of $1.50 per share. In 2017, the Company raised net proceeds (net of commissions) of approximately $12.0 million from the sale of approximately 8.9 million shares of common stock in the open market through the Controlled Equity Offering program with Cantor Fitzgerald at a weighted average price of $1.39 per share. Description of Stock-Based Compensation Plans 2000 Stock Plan (Incentive Stock Plan) In January 2000, the Company’s Board of Directors and stockholders adopted the DURECT Corporation 2000 Stock Plan, under which incentive stock options and non-statutory stock options and stock purchase rights may be granted to employees, consultants and non-employee directors. The 2000 Stock Plan was amended by written consent of the Board of Directors in March 2000 and written consent of the stockholders in August 2000. In April 2005, the Board of Directors approved certain amendments to the 2000 Stock Plan. At the Company’s annual stockholders meeting in June 2005, the stockholders approved the amendments of the 2000 Stock Plan to: (i) expand the types of awards that the Company may grant to eligible service providers under the Stock Plan to include restricted stock units, stock appreciation rights and other similar types of awards (including other awards under which recipients are not required to pay any purchase or exercise price) as well as cash awards; and (ii) include certain performance criteria that may be applied to awards granted under the Stock Plan. At the Company’s annual stockholders meeting in June 2010, the stockholders approved amendments of the 2000 Stock Plan to: (i) provide that the number of shares that remain available for issuance will be reduced by two shares for each share issued pursuant to an award (other than an option or stock appreciation right) granted on or after the date of the 2010 Annual Meeting; (ii) expand the types of transactions that might be considered repricings and option exchanges for which stockholder approval is required; (iii) provide that shares tendered or withheld in payment of the exercise price of an option or withheld to satisfy a withholding obligation, and all shares with respect to which a stock appreciation right is exercised, will not again be available for issuance under the Stock Plan; (iv) require that options and stock appreciation rights have an exercise price or base appreciation amount that is at least fair market value on the grant date, except in connection with certain corporate transactions, and that stock appreciation rights may not have longer than a 10-year term; (v) add new performance goals that may be used to provide “performance-based compensation” under the 2000 Stock Plan; (vi) extend the term of the 2000 Stock Plan to the date that is ten (10) years following the stockholders meeting; and (vii) expand the treatment of outstanding awards in connection with certain changes of control of the Company to cover mergers in which the consideration payable to stockholders is not solely securities of the successor corporation. At the Company’s annual stockholders meeting in June 2011, June 2014 and June 2016, the stockholders approved amendments of the 2000 Stock Plan to increase the number of shares of the Company’s common stock available for issuance by 5,500,000 shares, 4,000,000 shares and 5,000,000 shares, respectively, each of which had previously been approved by the Board of Directors. A total of 33,449,989 shares of common stock have been reserved for issuance under this plan. The plan expires in June 2020. In April 2013, the Board of Directors approved certain amendments to the 2000 Stock Plan to: (i) increase the number of stock options granted to a non-employee director on the date which such person first becomes a director from 30,000 to 70,000 shares of common stock; each option shall have a ten-year term, become exercisable in installments of one-third of the total number of options granted on each anniversary of the grant and have a two-year period following termination of Director status in which the former director can exercise the option; (ii) modify the exercise period for future option grants to a non-employee director in which a former director can exercise the option following termination of Director status from a one year period to a two-year period. Options granted under the 2000 Stock Plan expire no later than ten years from the date of grant. Options may be granted with different vesting terms from time to time not to exceed five years from the date of grant. The option price of an incentive stock option granted to an employee or of a nonstatutory stock option granted to any person who owns stock representing more than 10% of the total combined voting power of all classes of stock of the Company (or any parent or subsidiary) shall be no less than 110% of the fair market value per share on the date of grant. The option price of an incentive stock option granted to any other employee shall be no less than 100% of the fair market value per share on the date of grant. As of December 31, 2017, 3,348,584 shares of common stock were available for future grant and options to purchase 30,101,405 shares of common stock were outstanding under the 2000 Stock Plan. 2000 Directors’ Stock Option Plan In March 2000, the Board of Directors adopted the 2000 Directors’ Stock Option Plan, which provided for the issuance of stock options to non-employee directors of the Company. As of December 31, 2017, options to purchase 200,000 shares of common stock were outstanding under this plan, all of which were vested. The 2000 Directors’ Stock Option Plan expired in September 2000. Grants of stock options to our non-employee directors are made through the 2000 Stock Plan since September 2000. 2000 Employee Stock Purchase Plan In August 2000, the Company adopted the 2000 Employee Stock Purchase Plan. This purchase plan is implemented by a series of overlapping offering periods of 24 months’ duration, with new offering periods, other than the first offering period, beginning on May 1 and November 1 of each year and ending April 30 and October 31, respectively, two years later. The purchase plan allows eligible employees to purchase common stock through payroll deductions at a price equal to the lower of 85% of the fair market value of the Company’s common stock at the beginning of each offering period or at the end of each purchase period. The initial offering period commenced on the effectiveness of the Company’s initial public offering. In April 2010, the Board of Directors approved certain amendments to the 2000 Employee Stock Purchase Plan. At the Company’s annual stockholders meeting in June 2010, the stockholders approved the amendments of the 2000 Employee Stock Purchase Plan to: (i) increase the number of shares of our common stock authorized for issuance under the ESPP by 250,000 shares; (ii) extend the term of the ESPP to the date that is ten (10) years following the stockholders meeting; (iii) provide for six-month consecutive offering periods beginning on November 1, 2010; (iv) revise certain provisions to reflect the final regulations issued under Section 423 of the Code by the Internal Revenue Service; and (v) provide for the cash-out of options outstanding under an offering period in effect prior to the consummation of certain corporate transactions as an alternative to providing for a final purchase under such offering period. In March 2015, the Board of Directors approved certain amendments to the 2000 Employee Stock Purchase Plan. At the Company’s annual stockholders meeting in June 2015, the stockholders approved the amendments of the 2000 Employee Stock Purchase Plan to: (i) increase the number of shares of our common stock authorized for issuance under the ESPP by 350,000 shares; and (ii) extend the term of the ESPP to the date that is ten (10) years following the stockholders meeting. The plan expires in June 2025. A total of 2,900,000 shares of common stock have been reserved for issuance under this plan. As of December 31, 2017, 480,282 shares of common stock were available for future grant and 2,419,718 shares of common stock have been issued under the 2000 Employee Stock Purchase Plan. As of December 31, 2017, shares of common stock reserved for future issuance consisted of the following: December 31, 2017 Stock options outstanding 30,301,405 Stock options available for grant 3,348,584 Employee Stock Purchase Plan 480,282 34,130,271 A summary of stock option activity under all stock-based compensation plans is as follows: Number of Options Weighted Average Exercise Price Per Share Weighted Average Remaining Contractual Term (in Years) Aggregate Intrinsic Value (in millions) Outstanding at December 31, 2016 28,463,737 $ 2.09 5.11 $ 3.9 Options granted 4,660,594 $ 1.33 Options exercised (545,088 ) $ 1.03 Options forfeited (285,470 ) $ 1.26 Options expired (1,992,368 ) $ 4.06 Outstanding at December 31, 2017 30,301,405 $ 1.87 5.18 $ 0.4 Exercisable at December 31, 2017 26,280,797 $ 1.96 4.69 $ 0.4 Vested and expected to vest at December 31, 2017 30,301,405 $ 1.87 5.18 $ 0.4 The aggregate intrinsic value in the table above represents the total intrinsic value (i.e., the difference between the Company’s closing stock price on the last trading day of 2017 and the exercise price, multiplied by the number of in-the-money options) that would have been received by the option holders had all option holders exercised their in-the-money options on December 31, 2017. This amount changes based on the fair market value of the Company’s common stock. The total intrinsic value of options exercised was $328,000, $158,000 and $985,000 for the years ended December 31, 2017, 2016 and 2015, respectively. In lieu of providing cash bonuses to certain employees, in January 2017, 2016 and 2015, the Company granted its employees stock options to purchase 1.7 million, 1.4 million and 1.5 million shares, respectively, of the Company’s common stock, which vested immediately on the grant date. The weighted-average grant-date fair value of all options granted with exercise prices equal to fair market value was $0.92 in 2017, $0.81 in 2016 and $0.65 in 2015 determined by the Black-Scholes option valuation method. There were no options granted with exercise prices lower than fair market value in 2017, 2016 and 2015. Expenses for non-employee stock options are recorded over the vesting period of the options, with the value determined by the Black-Scholes option valuation method and remeasured over the vesting term. As of December 31, 2017, the Company had three stock-based equity compensation plans, which are described above. The employee stock-based compensation cost that has been included in the statements of operations and comprehensive loss is shown as below (in thousands): Year ended December 31, 2017 2016 2015 Cost of product revenues $ 109 $ 106 $ 108 Research and development 1,415 1,433 1,400 Selling, general and administrative 1,081 1,116 1,152 $ 2,605 $ 2,655 $ 2,660 Because the Company had a net operating loss carryforward as of December 31, 2017, no excess tax benefits for the tax deductions related to stock-based compensation expense were recognized in the statement of operations. Additionally, no incremental tax benefits were recognized from stock options exercised during 2016, which would have resulted in a reclassification to reduce net cash provided by operating activities with an offsetting increase in net cash provided by financing activities. Determining Fair Value Valuation and Expense Recognition. The Company estimates the fair value of stock options granted using the Black-Scholes option valuation model. The Company recognizes the expense on a straight-line basis. The expense for options is recognized over the requisite service periods of the awards, which is generally the vesting period. Expected Term. The expected term of options granted represents the period of time that the options are expected to be outstanding. The Company determines the expected life using historical options experience. This develops the expected life by taking the weighted average of the actual life of options exercised and cancelled and assumes that outstanding options are exercised uniformly from the current holding period through the end of the contractual life. Expected Volatility. The Company estimates the volatility of its common stock at the date of grant based on the historical volatility of the Company’s common stock. Risk-Free Rate. The Company bases the risk-free rate that it uses in the Black-Scholes option valuation model on the implied yield in effect at the time of option grant on U.S. Treasury zero-coupon issues with substantially equivalent remaining terms. Dividends. The Company has never paid any cash dividends on its common stock and the Company does not anticipate paying any cash dividends in the foreseeable future. Consequently, the Company uses an expected dividend yield of zero in the Black-Scholes option valuation model. The Company used the following assumptions to estimate the fair value of options granted (including fully vested options issued in January 2017, 2016 and 2015) and shares purchased under its stock plans and employee stock purchase plan for the years ended December 31, 2017, 2016 and 2015: Year ended December 31, 2017 2016 2015 Stock Options Risk-free rate 2.0-2.5% 1.3-2.4% 1.5-2.4% Expected dividend yield — — — Expected term (in years) 6.8-10.0 6.5-10.0 6.5-10.0 Volatility 75-86% 76-83% 78-85% Forfeiture rate 0.0 % 4.2 % 6.0 % (1) Effective January 1, 2017, the Company elected to account for forfeitures as they occur. Year ended December 31, 2017 2016 2015 Employee Stock Purchase Plan Risk-free rate 0.6-1.3% 0.3-0.6% 0.1-0.3% Expected dividend yield — — — Expected term (in years) 0.5 0.5 0.5 Volatility 44-146% 65-81% 68-95% There were 122,033, 114,025 and 113,625 shares purchased under the Company’s employee stock purchase plan during the years ended December 31, 2017, 2016 and 2015, respectively. Included in the statement of operations and comprehensive loss for the year ended December 31, 2017, 2016 and 2015 was $34,000, $45,000 and $62,000, respectively, in stock-based compensation expense related to the recognition of expenses related to shares purchased under the Company’s employee stock purchase plan. As of December 31, 2017, $3.0 million of total unrecognized compensation costs related to nonvested stock options is expected to be recognized over the respective vesting terms of each award through 2021. The weighted average term of the unrecognized stock-based compensation expense is 2.2 years. The following table summarizes information about stock options outstanding at December 31, 2017: Options Outstanding Options Exercisable Range of Exercise Price Number of Options Outstanding Weighted- Average Remaining Contractual Life (In years) Weighted- Average Exercise Price Number of Options Exercisable Weighted- Average Exercise Price $0.73 - $0.88 5,220,108 5.69 $ 0.84 4,600,285 $ 0.83 $0.93 - $1.16 3,199,479 7.66 $ 1.15 2,299,333 $ 1.15 $1.19 - $1.20 254,293 7.61 $ 1.19 251,793 $ 1.19 $1.21 - $1.21 3,390,536 5.10 $ 1.21 3,372,536 $ 1.21 $1.24 - $1.26 140,938 5.16 $ 1.26 140,938 $ 1.26 $1.31 - $1.31 3,606,656 8.59 $ 1.31 2,020,733 $ 1.31 $1.33 - $2.04 2,442,795 7.55 $ 1.49 1,686,929 $ 1.47 $2.09 - $2.09 3,802,601 4.68 $ 2.09 3,683,939 $ 2.09 $2.13 - $3.11 4,767,668 2.06 $ 2.61 4,747,980 $ 2.61 $3.26 - $6.29 3,476,331 1.66 $ 4.39 3,476,331 $ 4.39 $0.73 - $6.29 30,301,405 5.18 $ 1.87 26,280,797 $ 1.96 The Company received $562,000, $290,000 and $1.0 million in cash from option exercises under all stock-based compensation plans for the years ended December 31, 2017, 2016 and 2015, respectively.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Income Taxes	9. Income Taxes The Company accounts for income taxes using the liability method under ASC 740, Income Taxes The reconciliation of income tax expenses (benefit) at the statutory federal income tax rate of 34% to net income tax benefit included in the statements of operations and comprehensive loss for the years ended December 31, 2017, 2016 and 2015 is as follows (in thousands): Year Ended December 31, 2017 2016 2015 U.S. federal taxes benefit at statutory rate $ (1,307 ) $ (11,733 ) $ (7,681 ) State taxes 3 — — Change in valuation allowance (41,865 ) 10,847 7,725 Stock-based compensation 1,832 2,045 530 Change in deferreds 12 (3 ) 56 Deferred Tax Remeasurement 42,528 — — Other (1,353 ) (1,156 ) (577 ) Total income tax (benefit) provision $ (150 ) $ — $ 53 In 2017, 2016 and 2015, total income tax provision (benefit) expense was $(150,000), zero and $53,000, respectively. The Company has presented these amounts within interest and other income, net in the Statements of Operations and Comprehensive Loss. Deferred tax assets and liabilities reflect the net tax effects of net operating loss and research and other credit carryforwards and the temporary differences between the carrying amounts of assets and liabilities for financial reporting and the amounts used for income tax purposes. Significant components of the Company’s deferred tax assets and liabilities are as follows (in thousands): December 31, 2017 2016 Deferred tax assets: Net operating loss carryforwards $ 82,369 $ 123,107 Research and other credits 16,303 13,441 Capitalized research and development expenses — 10 Deferred revenue 395 874 Stock-based compensation 5,053 8,693 Other 2,261 3,405 Total deferred tax assets 106,381 149,530 Valuation allowance for deferred tax assets (106,381 ) (149,530 ) Deferred tax liabilities—Intangibles (244 ) (397 ) Net deferred tax assets and liabilities $ (244 ) $ (397 ) The Company recognizes deferred tax assets to the extent that the Company believes that these assets are more likely than not to be realized. In making such a determination, all available positive and negative evidence is considered, including future reversals of existing taxable temporary differences, projected future taxable income, tax-planning strategies, and results of recent operations. If it is determined that the Company would be able to realize deferred tax assets in the future in excess of their net recorded amount, the Company would make an adjustment to the deferred tax asset valuation allowance, which would reduce the provision for income taxes. The recognition and measurement of tax benefits requires significant judgment. Judgments concerning the recognition and measurement of tax benefit might change as new information becomes available. Given the Company’s history of operating losses, the net deferred tax assets have been fully offset by a valuation allowance. The valuation allowance decreased by $43.1 million during 2017 and increased by $11.4 million and $7.2 million during 2016 and 2015, respectively. As of December 31, 2017, the Company had net operating loss carryforwards for federal income tax purposes of approximately $327.1 million, which expire in the years 2019 through 2036, and federal research and development tax credits of approximately $12.5 million, which expire at various dates beginning in 2018 through 2037, if not utilized. As of December 31, 2017, the Company had net operating loss carryforwards for state income tax purposes of approximately $204.9 million, which expire in the years 2028 through 2036, if not utilized, and state research and development tax credits of approximately $13.7 million, which do not expire. Utilization of the net operating losses may be subject to a substantial annual limitation due to federal and state ownership change limitations. The annual limitation may result in the expiration of net operating losses before utilization. At December 31, 2017 and December 31, 2016, the Company had unrecognized tax benefits of approximately $7.8 and $7.0 million, respectively (none of which, if recognized, would affect the Company’s effective tax rate). The Company does not believe there will be any material changes in its unrecognized tax positions over the next twelve months. A reconciliation of the beginning and ending amount of unrecognized tax benefits is as follows (in thousands): December 31, 2017 2016 Balance at beginning of the year $ 6,982 $ 6,965 Decreased related to prior year tax positions — (737 ) Increased related to current year tax positions 867 754 Settlements — — Reductions due to lapse of applicable statute of limitations — — Balance at end of the year $ 7,849 $ 6,982 Interest and penalty costs related to unrecognized tax benefits, if any, are classified as a component of interest income and other income, net in the Statements of Operations and Comprehensive Loss. The Company did not recognize any interest and penalty expense related to unrecognized tax benefits for the years ended December 31, 2017, 2016 and 2015. The Company files income tax returns in the U.S. federal jurisdiction and various state jurisdictions. The Company is subject to U.S. federal and state income tax examination for calendar tax years ending 1998 through 2017 due to unutilized net operating losses and research credits. On December 22, 2017, the 2017 Tax Cut and Jobs Act (the Act) was enacted into law. Among other provisions, the Act reduces the Federal statutory corporate income tax rate from 35% to 21%, effective January 1, 2018. The Company is required to recognize the effect of the tax law changes in the period of enactment, such as the re-measuring our U.S. deferred tax assets and liabilities at a 21% rate, as well as reassessing the net realizability of our deferred tax assets and liabilities. The provisional amount related to the re-measurement of our deferred tax balance is a reduction of approximately $43.1 million. Due to the corresponding valuation allowance fully offsetting deferred taxes, there is no statement of operations impact. Given the significance of the legislation, in December 2017, the SEC staff issued Staff Accounting Bulletin No. 118, Income Tax Accounting Implications of the Tax Cuts and Jobs Act (SAB 118) which allows companies us to record provisional amounts during a measurement period not to extend beyond one year of the enactment date. Since the Act was passed late in the fourth quarter of 2017, and ongoing guidance and accounting interpretation are expected over the next 12 months, the Company considers the accounting of the deferred tax re-measurements to be incomplete. The Company expects to complete its analysis within the measurement period in accordance with SAB 118. The Company does not expect any material subsequent adjustment to these amounts. Any adjustments, if any, will have no impact to the statement of operations due to the Company’s full valuation allowance.

Unaudited Selected Quarterly Fi

Unaudited Selected Quarterly Financial Data	12 Months Ended
	Dec. 31, 2017
Quarterly Financial Information Disclosure [Abstract]
Unaudited Selected Quarterly Financial Data	10. Unaudited Selected Quarterly Financial Data (in thousands, except per share amounts) First Quarter Second Quarter Third Quarter Fourth Quarter 2017 2016 2017 2016 2017 2016 2017 2016 Revenue $ 4,567 $ 3,608 $ 4,319 $ 3,157 $ 20,746 $ 3,743 $ 19,538 $ 3,517 Net income (loss) $ (8,114 ) $ (7,852 ) $ (9,927 ) $ (9,014 ) $ 6,111 $ (8,832 ) $ 8,235 $ (8,811 ) Basic net income (loss) per share $ (0.06 ) $ (0.06 ) $ (0.07 ) $ (0.07 ) $ 0.04 $ (0.06 ) $ 0.06 $ (0.06 ) Diluted net income (loss) per share $ (0.06 ) $ (0.06 ) $ (0.07 ) $ (0.07 ) $ 0.04 $ (0.06 ) $ 0.05 $ (0.06 )

Subsequent Events

Subsequent Events	12 Months Ended
	Dec. 31, 2017
Subsequent Events [Abstract]
Subsequent Events	11. Subsequent Events As of March 2, 2018, the Company raised net proceeds (net of commissions) of approximately $2.8 million from the sale of 2.5 million shares of the Company’s common stock in the open market through the Controlled Equity Offering program with Cantor Fitzgerald at a weighted average price of $1.17 per share. As of March 2, 2018, the Company had up to approximately $14.9 million of common stock available for sale under the Controlled Equity Offering program and approximately $67.8 million of common stock available for sale under its shelf registration statement. In February 2018, the Company and Oxford Finance entered into a First Amendment of the Loan Agreement, which modified the terms of the Loan Agreement to change the first principal payment date from March 1, 2018 to December 1, 2018 and to increase the additional payment due when the term loan becomes due or upon the prepayment of the facility from 9.25% of the principal amount of the term loan to 10% of such amount. The interest rate and the maturity date remain unchanged, and the Company paid Oxford Finance a loan modification fee of $100,000.

Schedule II-Valuation and Quali

Schedule II-Valuation and Qualifying Accounts	12 Months Ended
	Dec. 31, 2017
Valuation And Qualifying Accounts [Abstract]
Schedule II-Valuation and Qualifying Accounts	SCHEDULE II—VALUATION AND QUALIFYING ACCOUNTS Year Ended December 31, 2017, 2016 and 2015 (in thousands) Balance at beginning of the year Additions (Reduction) to allowances Deductions Balance at end of the year Allowance for doubtful accounts Year ended December 31, 2017 $ 73 $ 165 $ (83 ) $ 155 Year ended December 31, 2016 $ 161 $ (70 ) $ (18 ) $ 73 Year ended December 31, 2015 $ 211 $ (38 ) $ (12 ) $ 161

Summary of Significant Accoun20

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2017
Accounting Policies [Abstract]
Nature of Operations	Nature of Operations DURECT Corporation (the Company) was incorporated in the state of Delaware on February 6, 1998. The Company is a biopharmaceutical company with research and development programs broadly falling into two categories: (i) new chemical entities derived from our Epigenetics Regulator Program, in which the Company attempts to discover and develop molecules which have not previously been approved and marketed as therapeutics, and (ii) Drug Delivery Programs, in which the Company applies its formulation expertise and technologies largely to active pharmaceutical ingredients whose safety and efficacy have previously been established but which the Company aims to improve in some manner through a new formulation. The Company has several products under development by itself and with third party collaborators. The Company also manufactures and sells osmotic pumps used in laboratory research, and designs, develops and manufactures a wide range of standard and custom biodegradable polymers and excipients for pharmaceutical and medical device clients for use as raw materials in their products. In addition, the Company conducts research and development of pharmaceutical products in collaboration with third party pharmaceutical and biotechnology companies.
Basis of Presentation and Use of Estimates	Basis of Presentation and Use of Estimates The Company’s financial statements have been prepared in accordance with U.S. generally accepted accounting principles (U.S. GAAP). The preparation of the accompanying Financial Statements conforms to accounting principles generally accepted in the U.S. which requires management to make judgments, estimates and assumptions that affect the reported amounts of assets, liabilities, equity, revenues and expenses, and related disclosures. On an ongoing basis, management evaluates its estimates including, but not limited to, those related to revenue recognition, the period of performance, identification of deliverables and evaluation of milestones with respect to our collaborations, the amounts of revenues, recoverability of inventory, certain accrued liabilities including accrued clinical trial liability, and stock-based compensation. The Company bases its estimates on historical experience and on various other market-specific and other relevant assumptions that the Company believe to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities that are not readily apparent from other sources. Actual results could differ materially from those estimates.
Liquidity and Need to Raise Additional Capital	Liquidity and Need to Raise Additional Capital As of December 31, 2017, the Company has an accumulated deficit of $443.8 million as well as negative cash flows from operating activities. The Company historically has had negative cash flows from operating activities and expects its negative cash flows to continue. The Company will continue to require substantial funds to continue research and development, including clinical trials of its product candidates. Management’s plans in order to meet its operating cash flow requirements include seeking additional collaborative agreements for certain of its programs and achieving milestone and other payments under its collaboration and licensing agreements as well as financing activities such as public offerings and private placements of its common stock, preferred stock offerings, issuances of debt and convertible debt instruments. There are no assurances that such additional funding will be obtained and that the Company will succeed in its future operations. If the Company cannot successfully raise additional capital and implement its strategic development plan, its liquidity, financial condition and business prospects will be materially and adversely affected.
Cash, Cash Equivalents and Investments	Cash, Cash Equivalents and Investments The Company considers all highly liquid investments with maturities of 90 days or less from the date of purchase to be cash equivalents. Investments with original maturities of greater than 90 days from the date of purchase but less than one year from the balance sheet date are classified as short-term investments, while investments with maturities in one year or beyond one year from the balance sheet date are classified as long-term investments. Management determines the appropriate classification of its cash equivalents and investment securities at the time of purchase and re-evaluates such determination as of each balance sheet date. Management has classified the Company’s cash equivalents and investments as available-for-sale securities in the accompanying financial statements. Available-for-sale securities are carried at fair value, with unrealized gains and losses reported as a component of accumulated other comprehensive loss. Realized gains and losses are included in interest income. There were no material realized gains or losses in the periods presented other than the gain realized from sale of a marketable equity security in the year ended December 31, 2015. The cost of securities sold is based on the specific identification method. The Company invests in debt instruments of government agencies, corporations, and money market funds with high credit ratings. The Company has established guidelines regarding diversification of its investments and their maturities with the objectives of maintaining safety and liquidity, while maximizing yield.
Concentrations of Credit Risk	Concentrations of Credit Risk Financial instruments that potentially subject the Company to credit risk consist principally of interest-bearing investments and trade receivables. The Company maintains cash, cash equivalents and investments with various major financial institutions. The Company performs periodic evaluations of the relative credit standing of these financial institutions. In addition, the Company performs periodic evaluations of the relative credit quality of its investments. Pharmaceutical companies and academic institutions account for a substantial portion of the Company’s trade receivables. The Company provides credit in the normal course of business to its customers and collateral for these receivables is generally not required. The risk associated with this concentration is limited to a certain extent due to the large number of accounts and their geographic dispersion. The Company monitors the creditworthiness of its customers to which it grants credit terms in the normal course of business. The Company maintains reserves for estimated credit losses and, to date, such losses have been immaterial in all periods presented.
Customer and Product Line Concentrations	Customer and Product Line Concentrations A portion of the Company’s revenue is derived from its ALZET mini pump product line, LACTEL biodegradable polymer product line and the sale of certain excipients for REMOXY ER and one excipient that is included in a currently marketed animal health product. In 2017, revenue from the sale of products from the ALZET product line and the LACTEL product line accounted for 14% and 12% of total revenue, respectively. In 2016, revenue from the ALZET product line and the LACTEL product line accounted for 51% and 31% of total revenue, respectively. In 2015, revenue from the ALZET product line and the LACTEL product line accounted for 36% and 22% of total revenue, respectively. In 2017, Sandoz and Indivior accounted for 41% and 25% of the Company’s total revenues. In 2016, Tolmar accounted for 15% of the Company’s total revenues. In 2015, Zogenix and Tolmar accounted for 26% and 11% of the Company’s total revenues. Total revenue by geographic region for the years 2017, 2016 and 2015 are as follows (in thousands): Year ended December 31, 2017 2016 2015 United States $ 11,323 $ 9,082 $ 14,289 Europe 34,261 1,945 1,817 Japan 1,395 1,413 1,897 Others 2,191 1,585 1,121 Total $ 49,170 $ 14,025 $ 19,124 Revenue by geography is determined by the location of the customer.
Inventories	Inventories Inventories are stated at the lower of cost or net realizable value, with cost determined on a first-in, first-out basis. Inventories, in part, include certain excipients that are sold to a customer for a currently marketed animal health product and included in several products in development or awaiting regulatory approval. In October 2017, the Company announced that PERSIST, the Phase 3 clinical trial for POSIMIR, did not meet its primary efficacy endpoint. As a result, the Company wrote down certain lots of inventory which are no longer considered to be probable for use prior to expiration and prepaid inventory related to a minimum purchase agreement for an excipient. In addition, the Company recorded a liability related to a minimum purchase agreement for the same excipient. In 2017, the Company recorded charges to cost of goods sold of approximately $2.0 million, of which approximately $503,000 related to the write-down of the cost basis of inventory on hand, $500,000 related to the prepaid inventory for the minimum purchase commitment for this excipient, and $1.0 million related to the accrual of a liability for the remaining minimum purchase commitment for the same excipient. As of December 31, 2017, the remaining carrying value of the excipient in the Company’s inventory was $69,000. In the event that management determines that the Company will not utilize all of these materials, there could be a potential write-off related to this inventory. If the Company is able to subsequently sell products made with raw materials that were previously written down, the Company will report an unusually high gross profit as there will be no associated cost of goods for these materials. The Company’s inventories consisted of the following (in thousands): December 31, 2017 2016 Raw materials $ 282 $ 745 Work in-process 1,182 1,672 Finished goods 1,699 1,365 Total inventories $ 3,163 $ 3,782
Property and Equipment	Property and Equipment Property and equipment are stated at cost less accumulated depreciation, which is computed using the straight-line method over the estimated useful lives of the assets, which range from three to five years. Leasehold improvements are amortized using the straight-line method over the estimated useful lives of the assets, or the terms of the related leases, whichever are shorter.
Goodwill	Goodwill Goodwill is periodically assessed and evaluated for impairment at the reporting unit level. The Company operates in one operating segment and also has only one reporting unit, which is the research, development and manufacturing of pharmaceutical products. The Company assesses the impairment of goodwill at least annually and whenever events or changes in circumstances indicate that the carrying value may not be recoverable. Factors the Company considers important which could trigger an impairment review include the following: • significant decline in our stock price for a prolonged period; • our market capitalization relative to net book value; • new information affecting the commercial value of the asset; • significant underperformance relative to expected historical or projected future operating results; • significant changes in the manner of our use of the acquired assets or the strategy for the Company’s overall business; and • significant negative industry or economic trends. As of December 31, 2017, the carrying value of goodwill was approximately $6.4 million and no impairment of goodwill has been recorded for any of the periods presented. The Company evaluates goodwill for impairment at least annually. In 2017, 2016 and 2015, goodwill was evaluated and no indicators of impairment were identified. Should goodwill become impaired, the Company may be required to record an impairment charge. To date, the Company has not recorded any impairment charge related to goodwill.
Impairment of Long-Lived Assets	Impairment of Long-Lived Assets The Company reviews long-lived assets, including property and equipment, intangible assets, and other long-term assets, for impairment whenever events or changes in business circumstances indicate that the carrying amount of the assets may not be fully recoverable. An impairment loss would be recognized when estimated undiscounted future cash flows expected to result from the use of the asset and its eventual disposition is less than its carrying amount. Impairment, if any, is calculated as the amount by which an asset’s carrying value exceeds its fair value, typically using discounted cash flows to determine fair value. Through December 31, 2017, there have been no material impairment losses.
Stock-Based Compensation	Stock-Based Compensation The Company accounts for share-based payments using a fair-value based method for costs related to all share-based payments, including stock options and stock issued under the Company’s employee stock purchase plan (ESPP). The Company estimates the fair value of share-based payment awards on the date of grant using an option-pricing model. See Note 9 for further information regarding stock-based compensation.
Revenue Recognition	Revenue Recognition Revenue from the sale of products is recognized when there is persuasive evidence that an arrangement exists, the product is shipped and title transfers to customers, provided no continuing obligation on the Company’s part exists, the price is fixed or determinable and the collectability of the amounts owed is reasonably assured. The Company enters into license and collaboration agreements under which it may receive upfront license fees, research funding and contingent milestone payments and royalties. The Company’s deliverables under these arrangements typically consist of granting licenses to intellectual property rights and providing research and development services. For multiple-element arrangements, each deliverable within a multiple deliverable revenue arrangement is accounted for as a separate unit of accounting if both of the following criteria are met: (1) the delivered item or items have value to the customer on a standalone basis and (2) for an arrangement that includes a general right of return relative to the delivered item(s), delivery or performance of the undelivered item(s) is considered probable and substantially in the Company’s control. The accounting standards contain a presumption that separate contracts entered into at or near the same time with the same entity or related parties were negotiated as a package and should be evaluated as a single agreement. Deferred revenue associated with a non-refundable payment received under a license and collaboration agreement for which the performance obligations are terminated will result in an immediate recognition of any remaining deferred revenue in the period that termination occurred provided that all performance obligations have been satisfied. From time-to-time, the Company also enters into sales of intellectual property rights under which it may receive upfront payments, contingent milestone payments and earn-outs from third party collaborators. The Company’s deliverable under these arrangements typically consists of sale of intellectual property rights, and does not contain any substantive continuing obligations subsequent to the transfer of the related rights, title, and interest to the buyer. The Company recognizes the upfront payment as revenue because such arrangement constitutes the Company's revenue-earning activities and is in line with its ordinary course of ongoing business operations. Research and development revenue related to services performed under the collaborative arrangements with the Company’s third-party collaborators is recognized as the related research and development services are performed. These research payments received under each respective agreement are not refundable and are generally based on reimbursement of qualified expenses, as defined in the agreements. Research and development expenses under the collaborative research and development agreements generally approximate or exceed the revenue recognized under such agreements over the term of the respective agreements. Deferred revenue may result when the Company does not expend the required level of effort during a specific period in comparison to funds received under the respective agreement. Milestone payments under collaborative arrangements are triggered either by the results of the Company’s research and development efforts or by specified sales results by a third-party collaborator. Milestones related to the Company’s development-based activities may include initiation of various phases of clinical trials, successful completion of a phase of development or results from a clinical trial, acceptance of a New Drug Application by the FDA or an equivalent filing with an equivalent regulatory agency in another territory, or regulatory approval by the FDA or by an equivalent regulatory agency in another territory. Due to the uncertainty involved in meeting these development-based milestones, the development-based milestones are considered to be substantive (i.e., not just achieved through passage of time) at the inception of the collaboration agreement. In addition, the amounts of the payments assigned thereto are considered to be commensurate with the enhancement of the value of the delivered intellectual property as a result of the Company’s performance. The Company’s involvement is generally necessary to the achievement of development-based milestones. The Company would account for development-based milestones as revenue upon achievement of the substantive milestone events. Milestones related to sales-based activities may be triggered upon events such as the first commercial sale of a product or when sales first achieve a defined level. Under the Company’s collaborative agreements, the Company’s third-party collaborators will take the lead in commercialization activities and the Company is typically not involved in the achievement of sales-based milestones. These sales-based milestones would be achieved after the completion of the Company’s development activities. The Company would account for the sales-based milestones in the same manner as royalties, with revenue recognized upon achievement of the milestone. In addition, upon the achievement of either development-based or sales-based milestone events, the Company has no future performance obligations related to any milestone payments.
Research and Development Expenses	Research and Development Expenses Research and development expenses are primarily comprised of salaries and benefits associated with research and development personnel, overhead and facility costs, preclinical and non-clinical development costs, clinical trial and related clinical manufacturing costs, contract services, and other outside costs. Research and development costs are expensed as incurred. Research and development costs paid to third parties under sponsored research agreements are recognized as the related services are performed. In addition, reimbursements of research and development expenses incurred by the Company’s partners are recorded as collaborative research and development revenue.
Comprehensive Income (Loss)	Comprehensive Income (Loss) Components of other comprehensive income (loss) are comprised entirely of unrealized gains and losses on the Company’s available-for-sale securities for all periods presented. Total comprehensive loss has been disclosed in the Company’s Statements of Comprehensive Loss.
Segment Reporting	Segment Reporting The Company operates in one operating segment, which is the research, development and manufacturing of pharmaceutical products.
Net Loss Per Share	Net Loss Per Share Basic net loss per share is calculated by dividing the net loss by the weighted-average number of common shares outstanding. Diluted net loss per share is computed using the weighted-average number of common shares outstanding and common stock equivalents (i.e., options to purchase common stock) outstanding during the period, if dilutive, using the treasury stock method for options. The numerators and denominators in the calculation of basic and diluted net loss per share were as follows (in thousands except per share amounts): Year Ended December 31, 2017 2016 2015 Numerators: Net loss $ (3,695 ) $ (34,509 ) $ (22,663 ) Denominators: Weighted average shares used to compute basic net loss per share 145,273 133,163 118,523 Effect of dilutive securities: Dilution from stock options — — — Dilution from ESPP — — — Dilutive common shares — — — Weighted average shares used to compute diluted net loss per share 145,273 133,163 118,523 Net loss per share: Basic $ (0.03 ) $ (0.26 ) $ (0.19 ) Diluted $ (0.03 ) $ (0.26 ) $ (0.19 ) The computation of diluted net loss per share for the years ended December 31, 2017, 2016 and 2015 excludes the impact of options to purchase 20.1 million, 18.7 million and 16.5 million shares of common stock outstanding, respectively, at December 31, 2017, 2016 and 2015, as such impact would be antidilutive.
Shipping and Handling	Shipping and Handling Costs related to shipping and handling are included in cost of revenues for all periods presented.
Operating Leases	Operating Leases The Company leases administrative, manufacturing and laboratory facilities under operating leases. Lease agreements may include rent holidays, rent escalation clauses and tenant improvement allowances. The Company recognizes scheduled rent increases on a straight-line basis over the lease term beginning with the date the Company takes possession of the leased space. The Company records tenant improvement allowances as deferred rent liabilities and amortizes the deferred rent over the terms of the lease to rent expense on the statements of operations and comprehensive loss.
Recent Accounting Pronouncements	Recent Accounting Pronouncements In May 2014, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update 2014-09, Revenue from Contracts with Customers (ASU 2014-09), which amends the guidance in former ASC 605, Revenue Recognition. The core principle of the guidance is that an entity should recognize revenue when it transfers promised goods or services to customers in an amount that reflects the consideration to which the company expects to be entitled in exchange for those goods or services. The guidance provides companies with two implementation methods. Companies can choose to apply the standard retrospectively to each prior reporting period presented (full retrospective application) or retrospectively with the cumulative effect of initially applying the standard as an adjustment to the opening balance of retained earnings of the annual reporting period that includes the date of initial application (modified retrospective application). The standard will be effective for the Company in the first quarter of 2018. To date, the Company’s revenues have been derived from product sales, license and collaboration agreements, and sale of intellectual property rights. Based on the Company’s analysis, it does not currently anticipate a material quantitative impact on product revenue as the timing of revenue recognition for product sales is not expected to change as product revenue will continue to be recognized when control of the goods is transferred to the customer. For the Company’s license and collaboration agreements, the consideration the Company is eligible to receive under these agreements typically consists of upfront payments, research and development funding, milestone payments, and royalties. For the Company’s agreements related to sale of intellectual property rights, the consideration the Company is eligible to receive under these agreements typically consists of upfront payments, milestone payments, and earn-outs. The Company has substantially completed its review of the impact that this new standard will have on its collaboration and license arrangements and intellectual property purchase agreements as well as on its financial statement disclosures. The Company will select the modified retrospective method to adopt the standard effective the first quarter of 2018. The Company expects that the impact of adopting the new standard will not be material. The Company does not expect a material cumulative-effect adjustment to accumulated deficit on January 1, 2018 upon adoption of the new standard. The new standard requires more robust disclosures than required by previous guidance, including disclosures related to disaggregation of revenue into appropriate categories, performance obligations, the judgments made in revenue recognition determinations, adjustments to revenue which relate to activities from previous quarters or years, any significant reversals of revenue, and costs to obtain or fulfill contracts. In February 2016, the Financial Accounting Standards Board (FASB) issued ASU No. 2016-02, Leases (Topic 842), which amends the existing accounting standards for leases. The new standard requires lessees to record a right-of-use asset and a corresponding lease liability on the balance sheet (with the exception of short-term leases). For lessees, leases will continue to be classified as either operating or financing in the income statement. This ASU becomes effective for the Company in the first quarter of fiscal year 2019 and early adoption is permitted. This ASU is required to be applied with a modified retrospective approach and requires application of the new standard at the beginning of the earliest comparative period presented. The Company is currently evaluating the impact that ASU 2016-02 will have on its financial statements.

Summary of Significant Accoun21

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2017
Accounting Policies [Abstract]
Summary of Total Revenue by Geographic Region	Total revenue by geographic region for the years 2017, 2016 and 2015 are as follows (in thousands): Year ended December 31, 2017 2016 2015 United States $ 11,323 $ 9,082 $ 14,289 Europe 34,261 1,945 1,817 Japan 1,395 1,413 1,897 Others 2,191 1,585 1,121 Total $ 49,170 $ 14,025 $ 19,124
Summary of Components of Inventories	The Company’s inventories consisted of the following (in thousands): December 31, 2017 2016 Raw materials $ 282 $ 745 Work in-process 1,182 1,672 Finished goods 1,699 1,365 Total inventories $ 3,163 $ 3,782
Summary of Numerators and Denominators in Calculation of Basic and Diluted Net Income (Loss) per Share	The numerators and denominators in the calculation of basic and diluted net loss per share were as follows (in thousands except per share amounts): Year Ended December 31, 2017 2016 2015 Numerators: Net loss $ (3,695 ) $ (34,509 ) $ (22,663 ) Denominators: Weighted average shares used to compute basic net loss per share 145,273 133,163 118,523 Effect of dilutive securities: Dilution from stock options — — — Dilution from ESPP — — — Dilutive common shares — — — Weighted average shares used to compute diluted net loss per share 145,273 133,163 118,523 Net loss per share: Basic $ (0.03 ) $ (0.26 ) $ (0.19 ) Diluted $ (0.03 ) $ (0.26 ) $ (0.19 )

Strategic Agreements (Tables)

Strategic Agreements (Tables)	12 Months Ended
	Dec. 31, 2017
Summary of Collaborative Research and Development and Other Revenues Associated with Company's Major Third-Party Collaborators	The collaborative research and development and other revenues associated with the Company’s major third-party collaborators are as follows (in thousands): Year ended December 31, 2017 2016 2015 Collaborator Sandoz AG (Sandoz) (1) $ 20,000 $ — $ — Zogenix, Inc. (Zogenix) (2) 835 555 4,898 Santen Pharmaceutical Co. Ltd. (Santen) (3) 294 514 824 Pain Therapeutics, Inc. (Pain Therapeutics) 109 670 1,385 Others 2,339 141 725 Total collaborative research and development and other revenue $ 23,577 $ 1,880 $ 7,832 (1) Amounts related to ratable recognition of upfront fees were $20.0 million in 2017 and zero in 2016 and 2015; the Company and Sandoz signed a license agreement effective June 2017. As of December 31, 2017, all of the $20.0 million upfront fee had been recognized as revenue as the Company’s contractual performance obligations had been fulfilled. (2) Amounts related to ratable recognition of upfront fees were $833,000 in 2017, $208,000 in 2016 and $255,000 in 2015, respectively. The Company and Zogenix signed a license agreement effective July 2011. In August 2017, the Company and Zogenix terminated the license agreement. As a result, the Company recognized as revenue all of the remaining upfront fees in the twelve months ended December 31, 2017 that had previously been deferred. (3) Amounts related to recognition of upfront fees were $199,000 in 2017, $228,000 in 2016 and $274,000 in 2015, respectively. The Company and Santen signed a license agreement effective December 2014.
Agreement with Zogenix, Inc. [Member]
Summary of Collaborative Research and Development Revenue Recognized	The following table provides a summary of collaborative research and development revenue recognized under the agreements with Zogenix (in thousands). The cumulative aggregate payments received by the Company as of December 31, 2017 were $20.1 million under these agreements. Year Ended December 31, 2017 2016 2015 Ratable recognition of upfront payment $ 833 $ 208 $ 255 Research and development expenses reimbursable by Zogenix 2 347 4,643 Total collaborative research and development revenue $ 835 $ 555 $ 4,898
Agreement with Santen Pharmaceutical Co., Ltd. [Member]
Summary of Collaborative Research and Development Revenue Recognized	The following table provides a summary of collaborative research and development revenue recognized under the Santen Agreement (in thousands). Year Ended December 31, 2017 2016 2015 Ratable recognition of upfront payment $ 199 $ 228 $ 274 Research and development expenses reimbursable by Santen 95 286 550 Total collaborative research and development revenue $ 294 $ 514 $ 824

Financial Instruments (Tables)

Financial Instruments (Tables)	12 Months Ended
	Dec. 31, 2017
Fair Value Disclosures [Abstract]
Fair Value Measurements of Assets and Liabilities	The following table sets forth the fair value of the Company’s financial assets that were measured at fair value on a recurring basis as of December 31, 2017 (in thousands): Level 1 Level 2 Level 3 Total Money market funds $ 568 $ — $ — $ 568 Certificates of deposit — 150 — 150 Commercial paper — 33,307 — 33,307 Corporate debt — 1,297 — 1,297 Total $ 568 $ 34,754 — $ 35,322 The following table sets forth the fair value of our financial assets that were measured at fair value on a recurring basis as of December 31, 2016 (in thousands): Level 1 Level 2 Level 3 Total Money market funds $ 693 $ — $ — $ 693 Certificates of deposit — 150 — 150 Commercial paper — 4,947 — 4,947 Corporate debt — 2,643 — 2,643 U.S. Government agencies — 14,459 — 14,459 Total $ 693 $ 22,199 $ — $ 22,892
Summary of Money Market Funds and Available-for-Sale Securities	The following is a summary of available-for-sale securities as of December 31, 2017 and 2016 (in thousands): December 31, 2017 Amortized Cost Unrealized Gain Unrealized Loss Estimated Fair Value Money market funds $ 568 $ — $ — $ 568 Certificates of deposit 150 — — 150 Commercial paper 33,307 — — 33,307 Corporate debt 1,298 — (1 ) 1,297 $ 35,323 $ — $ (1 ) $ 35,322 Reported as: Cash and cash equivalents $ 27,788 $ — $ — $ 27,788 Short-term investments 7,385 — (1 ) 7,384 Long-term restricted investments 150 — — 150 $ 35,323 $ — $ (1 ) $ 35,322 December 31, 2016 Amortized Cost Unrealized Gain Unrealized Loss Estimated Fair Value Money market funds $ 693 $ — $ — $ 693 Certificates of deposit 150 — — 150 Commercial paper 4,947 — — 4,947 Corporate debt 2,644 — (1 ) 2,643 U.S. Government agencies 14,461 1 (3 ) 14,459 $ 22,895 $ 1 $ (4 ) $ 22,892 Reported as: Cash and cash equivalents $ 3,142 $ — $ — $ 3,142 Short-term investments 19,603 1 (4 ) 19,600 Long-term restricted investments 150 — — 150 $ 22,895 $ 1 $ (4 ) $ 22,892
Summary of Cost and Estimated Fair Value of Available-for-Sale Securities by Contractual Maturity	The following is a summary of the cost and estimated fair value of available-for-sale securities at December 31, 2017, by contractual maturity (in thousands): December 31, 2017 Amortized Cost Estimated Fair Value Mature in one year or less $ 34,755 $ 34,754 $ 34,755 $ 34,754

Property and Equipment (Tables)

Property and Equipment (Tables)	12 Months Ended
	Dec. 31, 2017
Property Plant And Equipment [Abstract]
Property and Equipment	Property and equipment consist of the following (in thousands): December 31, 2017 2016 Equipment $ 12,688 $ 12,633 Leasehold improvement 9,929 10,007 Construction-in-progress 119 33 22,736 22,673 Less accumulated depreciation and amortization (21,807 ) (21,376 ) Property and equipment, net $ 929 $ 1,297

Commitments (Tables)

Commitments (Tables)	12 Months Ended
	Dec. 31, 2017
Commitments And Contingencies Disclosure [Abstract]
Summary of Lease Arrangements of Company Facilities	The Company has lease arrangements for its facilities in California and Alabama as follows. Location Approximate Square Feet Operation Expiration Cupertino, CA 30,000 sq. ft. Office, Laboratory and Manufacturing Lease expires 2019 (with an option to renew for an additional five years) Cupertino, CA 20,000 sq. ft. Office and Laboratory Lease expires 2019 (with an option to renew for an additional five years) Vacaville, CA 24,634 sq. ft. Manufacturing Lease expires 2018 Birmingham, AL 21,540 sq. ft. Office, Laboratory and Manufacturing Lease expires 2021 (with two options to renew the lease term for an additional five years each after the current lease expires)
Schedule of Future Operating Lease Minimum Payments	Future minimum payments under these noncancelable leases are as follows (in thousands): Year ending December 31, Operating Leases 2018 $ 1,948 2019 539 2020 324 2021 193 $ 3,004

Term Loan (Tables)

Term Loan (Tables)	12 Months Ended
	Dec. 31, 2017
Debt Disclosure [Abstract]
Schedule of Future Maturities and Interest Payments under Term Loan	Future maturities and interest payments under the term loan as of December 31, 2017, are as follows (in thousands): 2018 $ 8,698 2019 8,724 2020 6,642 Total minimum payments 24,064 Less amount representing interest (4,064 ) Gross balance of term loan 20,000 Less unamortized debt discount (85 ) Carrying value of term loan 19,915 Less term loan, current portion, net (7,281 ) Term loan, non-current portion, net $ 12,634

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	12 Months Ended
	Dec. 31, 2017
Equity [Abstract]
Summary of Shares of Common Stock Reserved for Future Issuance	As of December 31, 2017, shares of common stock reserved for future issuance consisted of the following: December 31, 2017 Stock options outstanding 30,301,405 Stock options available for grant 3,348,584 Employee Stock Purchase Plan 480,282 34,130,271
Summary of Stock Option Activity under all Stock-Based Compensation Plans	A summary of stock option activity under all stock-based compensation plans is as follows: Number of Options Weighted Average Exercise Price Per Share Weighted Average Remaining Contractual Term (in Years) Aggregate Intrinsic Value (in millions) Outstanding at December 31, 2016 28,463,737 $ 2.09 5.11 $ 3.9 Options granted 4,660,594 $ 1.33 Options exercised (545,088 ) $ 1.03 Options forfeited (285,470 ) $ 1.26 Options expired (1,992,368 ) $ 4.06 Outstanding at December 31, 2017 30,301,405 $ 1.87 5.18 $ 0.4 Exercisable at December 31, 2017 26,280,797 $ 1.96 4.69 $ 0.4 Vested and expected to vest at December 31, 2017 30,301,405 $ 1.87 5.18 $ 0.4
Summary of Employee Stock-Based Compensation Cost that has been Included in Statements of Operations and Comprehensive Loss	The employee stock-based compensation cost that has been included in the statements of operations and comprehensive loss is shown as below (in thousands): Year ended December 31, 2017 2016 2015 Cost of product revenues $ 109 $ 106 $ 108 Research and development 1,415 1,433 1,400 Selling, general and administrative 1,081 1,116 1,152 $ 2,605 $ 2,655 $ 2,660
Summary of Assumptions Used to Estimate Fair Value of Options Granted and Shares Purchased	The Company used the following assumptions to estimate the fair value of options granted (including fully vested options issued in January 2017, 2016 and 2015) and shares purchased under its stock plans and employee stock purchase plan for the years ended December 31, 2017, 2016 and 2015: Year ended December 31, 2017 2016 2015 Stock Options Risk-free rate 2.0-2.5% 1.3-2.4% 1.5-2.4% Expected dividend yield — — — Expected term (in years) 6.8-10.0 6.5-10.0 6.5-10.0 Volatility 75-86% 76-83% 78-85% Forfeiture rate 0.0 % 4.2 % 6.0 % (1) Effective January 1, 2017, the Company elected to account for forfeitures as they occur. Year ended December 31, 2017 2016 2015 Employee Stock Purchase Plan Risk-free rate 0.6-1.3% 0.3-0.6% 0.1-0.3% Expected dividend yield — — — Expected term (in years) 0.5 0.5 0.5 Volatility 44-146% 65-81% 68-95%
Summary of Stock Options Outstanding	The following table summarizes information about stock options outstanding at December 31, 2017: Options Outstanding Options Exercisable Range of Exercise Price Number of Options Outstanding Weighted- Average Remaining Contractual Life (In years) Weighted- Average Exercise Price Number of Options Exercisable Weighted- Average Exercise Price $0.73 - $0.88 5,220,108 5.69 $ 0.84 4,600,285 $ 0.83 $0.93 - $1.16 3,199,479 7.66 $ 1.15 2,299,333 $ 1.15 $1.19 - $1.20 254,293 7.61 $ 1.19 251,793 $ 1.19 $1.21 - $1.21 3,390,536 5.10 $ 1.21 3,372,536 $ 1.21 $1.24 - $1.26 140,938 5.16 $ 1.26 140,938 $ 1.26 $1.31 - $1.31 3,606,656 8.59 $ 1.31 2,020,733 $ 1.31 $1.33 - $2.04 2,442,795 7.55 $ 1.49 1,686,929 $ 1.47 $2.09 - $2.09 3,802,601 4.68 $ 2.09 3,683,939 $ 2.09 $2.13 - $3.11 4,767,668 2.06 $ 2.61 4,747,980 $ 2.61 $3.26 - $6.29 3,476,331 1.66 $ 4.39 3,476,331 $ 4.39 $0.73 - $6.29 30,301,405 5.18 $ 1.87 26,280,797 $ 1.96

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Reconciliation of Income Tax Expenses (Benefit)	The reconciliation of income tax expenses (benefit) at the statutory federal income tax rate of 34% to net income tax benefit included in the statements of operations and comprehensive loss for the years ended December 31, 2017, 2016 and 2015 is as follows (in thousands): Year Ended December 31, 2017 2016 2015 U.S. federal taxes benefit at statutory rate $ (1,307 ) $ (11,733 ) $ (7,681 ) State taxes 3 — — Change in valuation allowance (41,865 ) 10,847 7,725 Stock-based compensation 1,832 2,045 530 Change in deferreds 12 (3 ) 56 Deferred Tax Remeasurement 42,528 — — Other (1,353 ) (1,156 ) (577 ) Total income tax (benefit) provision $ (150 ) $ — $ 53
Summary of Components of Company's Deferred Tax Assets	Significant components of the Company’s deferred tax assets and liabilities are as follows (in thousands): December 31, 2017 2016 Deferred tax assets: Net operating loss carryforwards $ 82,369 $ 123,107 Research and other credits 16,303 13,441 Capitalized research and development expenses — 10 Deferred revenue 395 874 Stock-based compensation 5,053 8,693 Other 2,261 3,405 Total deferred tax assets 106,381 149,530 Valuation allowance for deferred tax assets (106,381 ) (149,530 ) Deferred tax liabilities—Intangibles (244 ) (397 ) Net deferred tax assets and liabilities $ (244 ) $ (397 )
Reconciliation of Unrecognized Tax Benefits	A reconciliation of the beginning and ending amount of unrecognized tax benefits is as follows (in thousands): December 31, 2017 2016 Balance at beginning of the year $ 6,982 $ 6,965 Decreased related to prior year tax positions — (737 ) Increased related to current year tax positions 867 754 Settlements — — Reductions due to lapse of applicable statute of limitations — — Balance at end of the year $ 7,849 $ 6,982

Unaudited Selected Quarterly 29

Unaudited Selected Quarterly Financial Data (Tables)	12 Months Ended
	Dec. 31, 2017
Quarterly Financial Information Disclosure [Abstract]
Selected Quarterly Financial Data	First Quarter Second Quarter Third Quarter Fourth Quarter 2017 2016 2017 2016 2017 2016 2017 2016 Revenue $ 4,567 $ 3,608 $ 4,319 $ 3,157 $ 20,746 $ 3,743 $ 19,538 $ 3,517 Net income (loss) $ (8,114 ) $ (7,852 ) $ (9,927 ) $ (9,014 ) $ 6,111 $ (8,832 ) $ 8,235 $ (8,811 ) Basic net income (loss) per share $ (0.06 ) $ (0.06 ) $ (0.07 ) $ (0.07 ) $ 0.04 $ (0.06 ) $ 0.06 $ (0.06 ) Diluted net income (loss) per share $ (0.06 ) $ (0.06 ) $ (0.07 ) $ (0.07 ) $ 0.04 $ (0.06 ) $ 0.05 $ (0.06 )

Summary of Significant Accoun30

Summary of Significant Accounting Policies - Additional Information (Detail) shares in Millions	12 Months Ended
	Dec. 31, 2017USD ($)Segmentshares	Dec. 31, 2016USD ($)shares	Dec. 31, 2015USD ($)shares
Summary Of Significant Accounting Policies [Line Items]
State of incorporation	Delaware
Date of incorporation	Feb. 6, 1998
Accumulated deficit	$ 443,772,000	$ 440,077,000
Highly liquid investments maturity period	90 days or less
Long-term investments maturity period	One year or beyond
Realized gains or losses on cash, cash equivalents and investments	$ 0	0
Cost of goods sold	6,633,000	5,290,000	$ 3,905,000
Write-down of the cost basis of inventory on hand	2,259,000	687,000	303,000
Minimum purchase commitment	500,000
Inventories	$ 3,163,000	3,782,000
Number of operating segment | Segment	1
Number of reporting segment | Segment	1
Goodwill	$ 6,399,000	6,399,000
Goodwill impairment	0	$ 0	$ 0
Long-lived assets, impairment losses	$ 0
Options to purchase common stock excluded from computation of diluted net loss per share | shares	20.1	18.7	16.5
Agreement with Pain Therapeutics, Inc. [Member]
Summary Of Significant Accounting Policies [Line Items]
Cost of goods sold	$ 0	$ 216,000	$ 51,000
Agreement with Pain Therapeutics, Inc. [Member] | PERSIST, Phase 3 Clinical Trial for POSIMIR [Member]
Summary Of Significant Accounting Policies [Line Items]
Cost of goods sold	2,000,000
Write-down of the cost basis of inventory on hand	503,000
Minimum purchase commitment	1,000,000
Inventories	69,000
Agreement with Pain Therapeutics, Inc. [Member] | PERSIST, Phase 3 Clinical Trial for POSIMIR [Member] | Prepaid Inventory [Member]
Summary Of Significant Accounting Policies [Line Items]
Minimum purchase commitment	$ 500,000
Sales Revenue Net [Member] | Customer Concentration Risk [Member] | Sandoz [Member]
Summary Of Significant Accounting Policies [Line Items]
Percentage of revenue accounted in Company's total revenue	41.00%
Sales Revenue Net [Member] | Customer Concentration Risk [Member] | Zogenix [Member]
Summary Of Significant Accounting Policies [Line Items]
Percentage of revenue accounted in Company's total revenue			26.00%
Sales Revenue Net [Member] | Customer Concentration Risk [Member] | Indivior [Member]
Summary Of Significant Accounting Policies [Line Items]
Percentage of revenue accounted in Company's total revenue	25.00%
Sales Revenue Net [Member] | Customer Concentration Risk [Member] | Tolmar Inc. [Member]
Summary Of Significant Accounting Policies [Line Items]
Percentage of revenue accounted in Company's total revenue		15.00%	11.00%
Sales Revenue Net [Member] | ALZET Product Line [Member] | Product Concentration Risk [Member]
Summary Of Significant Accounting Policies [Line Items]
Percentage of revenue accounted in Company's total revenue	14.00%	51.00%	36.00%
Sales Revenue Net [Member] | LACTEL Product Line [Member] | Product Concentration Risk [Member]
Summary Of Significant Accounting Policies [Line Items]
Percentage of revenue accounted in Company's total revenue	12.00%	31.00%	22.00%
Minimum [Member]
Summary Of Significant Accounting Policies [Line Items]
Short-term investments maturity period	90 days
Property and equipment, estimated useful life	3 years
Maximum [Member]
Summary Of Significant Accounting Policies [Line Items]
Short-term investments maturity period	1 year
Property and equipment, estimated useful life	5 years

Summary of Significant Accoun31

Summary of Significant Accounting Policies - Summary of Total Revenue by Geographic Region (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	$ 19,538	$ 20,746	$ 4,319	$ 4,567	$ 3,517	$ 3,743	$ 3,157	$ 3,608	$ 49,170	$ 14,025	$ 19,124
United States [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue									11,323	9,082	14,289
Europe [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue									34,261	1,945	1,817
Japan [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue									1,395	1,413	1,897
Others [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue									$ 2,191	$ 1,585	$ 1,121

Summary of Significant Accoun32

Summary of Significant Accounting Policies - Summary of Components of Inventories (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Inventory Net [Abstract]
Raw materials	$ 282	$ 745
Work in-process	1,182	1,672
Finished goods	1,699	1,365
Total inventories	$ 3,163	$ 3,782

Summary of Significant Accoun33

Summary of Significant Accounting Policies - Summary of Numerators and Denominators in Calculation of Basic and Diluted Net Loss per Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Numerators:
Net loss	$ 8,235	$ 6,111	$ (9,927)	$ (8,114)	$ (8,811)	$ (8,832)	$ (9,014)	$ (7,852)	$ (3,695)	$ (34,509)	$ (22,663)
Denominators:
Weighted average shares used to compute basic net loss per share									145,273	133,163	118,523
Effect of dilutive securities:
Dilution from stock options									0	0	0
Dilution from ESPP									0	0	0
Dilutive common shares									0	0	0
Weighted average shares used to compute diluted net loss per share									145,273	133,163	118,523
Net loss per share:
Basic	$ 0.06	$ 0.04	$ (0.07)	$ (0.06)	$ (0.06)	$ (0.06)	$ (0.07)	$ (0.06)	$ (0.03)	$ (0.26)	$ (0.19)
Diluted	$ 0.05	$ 0.04	$ (0.07)	$ (0.06)	$ (0.06)	$ (0.06)	$ (0.07)	$ (0.06)	$ (0.03)	$ (0.26)	$ (0.19)

Strategic Agreements - Summary

Strategic Agreements - Summary of Collaborative Research and Development and Other Revenues Associated with Company's Major Third-Party Collaborators (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Total collaborative research and development and other revenue	$ 23,577	$ 1,880	$ 7,832
Agreement with Sandoz AG [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Total collaborative research and development and other revenue	20,000	0	0
Agreement with Zogenix, Inc. [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Total collaborative research and development and other revenue	835	555	4,898
Agreement with Santen Pharmaceutical Co., Ltd. [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Total collaborative research and development and other revenue	294	514	824
Agreement with Pain Therapeutics, Inc. [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Total collaborative research and development and other revenue	109	670	1,385
Agreements With Other Third Party Collaborators [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Total collaborative research and development and other revenue	$ 2,339	$ 141	$ 725

Strategic Agreements - Summar35

Strategic Agreements - Summary of Collaborative Research and Development and Other Revenues Associated with Company's Major Third-Party Collaborators (Parenthetical) (Detail) - USD ($) $ in Thousands	Dec. 11, 2014	May 31, 2017	Sep. 30, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Agreement with Sandoz AG [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Amounts related to the ratable recognition of upfront fees				$ 20,000	$ 0	$ 0
Upfront license fee		$ 20,000		20,000
Agreement with Zogenix, Inc. [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Amounts related to the ratable recognition of upfront fees			$ 750	$ 833	208	255
Agreement termination month and year				2017-08
Agreement with Santen Pharmaceutical Co., Ltd. [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Amounts related to the ratable recognition of upfront fees				$ 199	$ 228	$ 274
Upfront license fee	$ 2,000

Strategic Agreements - Addition

Strategic Agreements - Additional Information (Detail) - Subsequent Event [Member]	Mar. 02, 2018USD ($)	Mar. 02, 2018USD ($)
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Milestone payments received	$ 0	$ 0
Maximum [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Future milestone payments	337,500,000
Early stage clinical testing [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Development-based milestones	2,000,000	2,000,000
Late stage clinical testing [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Development-based milestones	3,000,000	3,000,000
Regulatory filings [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Development-based milestones	8,000,000	8,000,000
Regulatory approvals [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Development-based milestones	31,500,000	$ 31,500,000
Development-Based Milestones [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Future milestone payments	44,500,000
Sales-Based Milestones [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Future milestone payments	$ 293,000,000

Strategic Agreements - Agreemen

Strategic Agreements - Agreement with Sandoz AG - Additional Information (Detail) - USD ($)	1 Months Ended	12 Months Ended
	May 31, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Total collaborative research and development and other revenue		$ 23,577,000	$ 1,880,000	$ 7,832,000
Agreement with Sandoz AG [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Upfront license fee	$ 20,000,000	20,000,000
Regulatory milestones currently feasible	$ 30,000,000
Notice period to terminate agreement, in days	30 days
Notice period to terminate rights, in months	6 months
Total collaborative research and development and other revenue		20,000,000	$ 0	$ 0
Cumulative aggregate payments received by the Company		$ 20,000,000
Agreement with Sandoz AG [Member] | Maximum [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Performance milestone payments based on successful development	$ 43,000,000
Agreement with Sandoz AG [Member] | Sales-Based Milestones [Member] | Maximum [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Performance milestone payments based on successful development	$ 230,000,000

Strategic Agreements - Patent P

Strategic Agreements - Patent Purchase Agreement with Indivior - Additional Information (Detail) - USD ($) $ in Thousands	Sep. 26, 2017	Dec. 31, 2017
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Revenue from sale of intellectual property rights		$ 12,500
Patent Purchase Agreement with Indivior [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Upfront non-refundable payment received	$ 12,500
Granted patents extending year, minimum	2,026
Revenue from sale of intellectual property rights		$ 12,500
Patent Purchase Agreement with Indivior [Member] | Regulatory Based Milestone [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Performance milestone payments based on successful development	$ 5,000

Strategic Agreements - Agreem39

Strategic Agreements - Agreement with Pain Therapeutics, Inc. - Additional Information (Detail)	1 Months Ended	12 Months Ended
	Dec. 31, 2002Drug	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)License
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Total collaborative research and development and other revenue		$ 23,577,000	$ 1,880,000	$ 7,832,000
Product revenue, net		13,093,000	12,145,000	11,292,000
Cost of goods sold		6,633,000	5,290,000	3,905,000
Agreement with Pain Therapeutics, Inc. [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Number of specified opioid drugs | Drug	4
Upfront license fee		1,000,000
Performance milestone payments based on successful development		3,000,000
Revenue recognition milestone achieved		1,500,000
Total collaborative research and development and other revenue		109,000	670,000	$ 1,385,000
Number of remaining licensed products | License				3
Cumulative aggregate payments received by the Company		40,400,000
Product revenue, net		0	653,000	$ 96,000
Cost of goods sold		0	$ 216,000	$ 51,000
Agreement with Pain Therapeutics, Inc. [Member] | Development-Based Milestones [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Performance milestone payments based on successful development		3,000,000
Agreement with Pain Therapeutics, Inc. [Member] | Sales-Based Milestones [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Performance milestone payments based on successful development		$ 0

Strategic Agreements - Agreem40

Strategic Agreements - Agreement with Zogenix, Inc. - Additional Information (Detail) - Agreement with Zogenix, Inc. [Member] - USD ($) $ in Thousands	1 Months Ended	3 Months Ended	12 Months Ended
	Jul. 31, 2011	Sep. 30, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Agreement termination month and year			2017-08
Amounts related to the ratable recognition of upfront fees		$ 750	$ 833	$ 208	$ 255
Cumulative aggregate payments received by the Company			20,100
Up-front Payment Arrangement [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Non-refundable upfront fee	$ 2,250		$ 2,250

Strategic Agreements - Summar41

Strategic Agreements - Summary of Collaborative Research and Development Revenue Recognized (Detail) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Sep. 30, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Total collaborative research and development revenue		$ 23,577	$ 1,880	$ 7,832
Agreement with Zogenix, Inc. [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Ratable recognition of upfront payment	$ 750	833	208	255
Research and development expenses reimbursable by the Company		2	347	4,643
Total collaborative research and development revenue		835	555	4,898
Agreement with Santen Pharmaceutical Co., Ltd. [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Ratable recognition of upfront payment		199	228	274
Research and development expenses reimbursable by the Company		95	286	550
Total collaborative research and development revenue		$ 294	$ 514	$ 824

Strategic Agreements - Agreem42

Strategic Agreements - Agreement with Santen Pharmaceutical Co., Ltd. - Additional Information (Detail) - Agreement with Santen Pharmaceutical Co., Ltd. [Member] - USD ($)	Dec. 11, 2014	Dec. 31, 2017
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Upfront license fee	$ 2,000,000
Cumulative aggregate payments received by the Company		$ 3,300,000
Maximum [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Future milestone payments	76,000,000
Development-Based Milestones [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Future milestone payments	13,000,000
Commercialization-Based Milestones [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Future milestone payments	$ 63,000,000
Revenue recognition milestone achieved		$ 0

Financial Instruments - Fair Va

Financial Instruments - Fair Value Measurements of Assets and Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total	$ 35,322	$ 22,892
Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total	568	693
Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total	34,754	22,199
Money market funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total	568	693
Money market funds [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total	568	693
Certificates of deposit [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total	150	150
Certificates of deposit [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total	150	150
Commercial paper [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total	33,307	4,947
Commercial paper [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total	33,307	4,947
Corporate debt [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total	1,297	2,643
Corporate debt [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total	$ 1,297	2,643
U.S. Government agencies [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total		14,459
U.S. Government agencies [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total		$ 14,459

Financial Instruments - Summary

Financial Instruments - Summary of Money Market Funds and Available-for-Sale Securities (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 35,323	$ 22,895
Unrealized Gain		1
Unrealized Loss	(1)	(4)
Estimated Fair Value	35,322	22,892
Money market funds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	568	693
Estimated Fair Value	568	693
Certificates of deposit [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	150	150
Estimated Fair Value	150	150
Commercial paper [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	33,307	4,947
Estimated Fair Value	33,307	4,947
Corporate debt [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	1,298	2,644
Unrealized Loss	(1)	(1)
Estimated Fair Value	1,297	2,643
Cash and cash equivalents [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	27,788	3,142
Estimated Fair Value	27,788	3,142
Short-term investments [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	7,385	19,603
Unrealized Gain		1
Unrealized Loss	(1)	(4)
Estimated Fair Value	7,384	19,600
Long-term restricted investments [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	150	150
Estimated Fair Value	$ 150	150
U.S. Government agencies [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost		14,461
Unrealized Gain		1
Unrealized Loss		(3)
Estimated Fair Value		$ 14,459

Financial Instruments - Summa45

Financial Instruments - Summary of Cost and Estimated Fair Value of Available-for-Sale Securities by Contractual Maturity (Detail) $ in Thousands	Dec. 31, 2017USD ($)
Investments Debt And Equity Securities [Abstract]
Mature in one year or less, Amortized Cost	$ 34,755
Amortized Cost	34,755
Mature in one year or less, Estimated Fair Value	34,754
Estimated Fair Value	$ 34,754

Financial Instruments - Additio

Financial Instruments - Additional Information (Detail)	Dec. 31, 2017USD ($)
Investments Debt And Equity Securities [Abstract]
Unrealized loss of securities	$ 0

Property and Equipment - Proper

Property and Equipment - Property and Equipment (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 22,736	$ 22,673
Less accumulated depreciation and amortization	(21,807)	(21,376)
Property and equipment, net	929	1,297
Equipment [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	12,688	12,633
Leasehold improvement [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	9,929	10,007
Construction-in-progress [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 119	$ 33

Property and Equipment - Additi

Property and Equipment - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Property Plant And Equipment [Abstract]
Depreciation expense	$ 437,000	$ 416,000	$ 425,000
Amortization expense	0	$ 0	$ 1,000
Restoration cost	$ 611,000

Restricted Investments - Additi

Restricted Investments - Additional Information (Detail) - USD ($)	Dec. 31, 2017	Dec. 31, 2016
Restricted Investments [Line Items]
Restricted investments in connection with deposits on letters of credit	$ 150,000	$ 150,000
California [Member]
Restricted Investments [Line Items]
Restricted investments in connection with deposits on letters of credit	$ 150,000	$ 150,000

Commitments - Summary of Lease

Commitments - Summary of Lease Arrangements of Company Facilities (Detail)	12 Months Ended
	Dec. 31, 2017ft²Option
Cupertino, CA [Member] | Office, Laboratory and Manufacturing [Member]
Property Subject To Or Available For Operating Lease [Line Items]
Approximate Square Feet	30,000
Expiration	Lease expires 2019 (with an option to renew for an additional five years)
Lease expiration year	2,019
Lease renewal term	5 years
Cupertino, CA [Member] | Office and Laboratory [Member]
Property Subject To Or Available For Operating Lease [Line Items]
Approximate Square Feet	20,000
Expiration	Lease expires 2019 (with an option to renew for an additional five years)
Lease expiration year	2,019
Lease renewal term	5 years
Vacaville, CA [Member] | Manufacturing [Member]
Property Subject To Or Available For Operating Lease [Line Items]
Approximate Square Feet	24,634
Expiration	Lease expires 2018
Lease expiration year	2,018
Birmingham, AL [Member] | Office, Laboratory and Manufacturing [Member]
Property Subject To Or Available For Operating Lease [Line Items]
Approximate Square Feet	21,540
Expiration	Lease expires 2021 (with two options to renew the lease term for an additional five years each after the current lease expires)
Lease expiration year	2,021
Lease renewal term	5 years
Number of renewal option for lease | Option	2

Commitments - Additional Inform

Commitments - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Commitment And Contingencies [Line Items]
Rent expenses of operating leases	$ 1,900,000	$ 1,900,000	$ 1,900,000
Remaining minimum purchase commitment	500,000
Cost of goods sold	6,633,000	$ 5,290,000	$ 3,905,000
Other Purchase Commitments [Member]
Commitment And Contingencies [Line Items]
Cost of goods sold	$ 500,000

Commitments - Schedule of Futur

Commitments - Schedule of Future Operating Lease Minimum Payments (Detail) $ in Thousands	Dec. 31, 2017USD ($)
Leases [Abstract]
2,018	$ 1,948
2,019	539
2,020	324
2,021	193
Total operating leases future minimum payments	$ 3,004

Term Loan - Additional Informat

Term Loan - Additional Information (Detail) - USD ($)	Jun. 26, 2014	Jul. 31, 2016	Jul. 31, 2015	Dec. 31, 2017
Debt Instrument [Line Items]
Debt instrument, covenants in compliance				The Company was in compliance with all material covenants under the Loan Agreement and there had been no material adverse change.
Oxford Finance LLC Term Loan [Member]
Debt Instrument [Line Items]
Secured term loan	$ 20,000,000
Term loan, maturity date	Jul. 1, 2018		Jul. 1, 2019
Term loan repayment description				The term loan repayment schedule provided for interest only payments for the first 18 months, followed by consecutive equal monthly payments of principal and interest in arrears starting on February 1, 2016
First principal payment date	Feb. 1, 2016		Feb. 1, 2017
Interest rate on term loan	7.95%
Facility fee paid at final payment	$ 150,000
Percentage of an additional payment equal to principal amount	8.00%		10.00%
Proceeds from long term debt, net	$ 19,800,000
Debt offering/issuance costs	$ 1,600,000
Loan modification fee			$ 240,000
Oxford Finance LLC Term Loan [Member] | Minimum [Member]
Debt Instrument [Line Items]
Percentage of prepayment fee	1.00%
Oxford Finance LLC Term Loan [Member] | Maximum [Member]
Debt Instrument [Line Items]
Percentage of prepayment fee	3.00%
Oxford Finance 2016 Term Loan [Member]
Debt Instrument [Line Items]
Secured term loan		$ 20,000,000
Term loan, maturity date		Aug. 1, 2020
Term loan repayment description				The 2016 Loan Agreement provides for interest only payments for the first 18 months, followed by consecutive monthly payments of principal and interest in arrears starting on March 1, 2018
First principal payment date		Mar. 1, 2018
Interest rate on term loan		7.95%		8.87%
Facility fee paid at final payment		$ 150,000
Percentage of an additional payment equal to principal amount		9.25%
Debt offering/issuance costs		$ 1,900,000
Term loan, floating interest rate basis				index rate plus a spread
Oxford Finance 2016 Term Loan [Member] | Minimum [Member]
Debt Instrument [Line Items]
Percentage of prepayment fee		1.00%
Oxford Finance 2016 Term Loan [Member] | Maximum [Member]
Debt Instrument [Line Items]
Percentage of prepayment fee		3.00%

Term Loan - Schedule of Future

Term Loan - Schedule of Future Maturities and Interest Payments under Term Loan (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Future maturities and interest payments under the term loan:
2,018	$ 8,698
2,019	8,724
2,020	6,642
Total minimum payments	24,064
Less amount representing interest	(4,064)
Gross balance of term loan	20,000
Less unamortized debt discount	(85)
Carrying value of term loan	19,915
Less term loan, current portion, net	(7,281)	$ (19,853)
Term loan, non-current portion, net	$ 12,634

Stockholders' Equity - Common S

Stockholders' Equity - Common Stock - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands, shares in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Nov. 30, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Proceeds from sale of common stock, net of commission	$ 11,989	$ 23,745	$ 14,290
Controlled Equity Offering Program [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Proceeds from sale of common stock, net of commission	$ 12,000	$ 7,600	$ 14,300
Sale of common stock during period	8.9	5.2	7.1
Common stock weighted average price	$ 1.39	$ 1.50	$ 2.09
Underwritten public offering [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Proceeds from sale of common stock, net of commission		$ 16,100
Sale of common stock during period		13.8
Public offering price for common stock		$ 1.25
Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Securities offered				$ 125,000
Cantor Fitzgerald Co [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Securities offered				$ 40,000

Stockholders' Equity - 2000 Sto

Stockholders' Equity - 2000 Stock Plan (Incentive Stock Plan) - Additional Information (Detail) - shares	1 Months Ended				3 Months Ended	12 Months Ended
	Jun. 30, 2016	Jun. 30, 2014	Apr. 30, 2013	Jun. 30, 2011	Mar. 31, 2000	Dec. 31, 2017	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Reserved common stock for issuance						34,130,271
Options exercised, shares						4,660,594
Shares available for future grant						3,348,584
Common stock outstanding						30,301,405	28,463,737
2000 Stock Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum expiration term of stock appreciation rights						10 years
Extended term of stock plan to the date						10 years
Issuance of common stock upon equity financing, net of issuance cost	5,000,000	4,000,000		5,500,000
Reserved common stock for issuance						33,449,989
Plan expiry date						Jun. 30, 2020
Options exercised, shares			70,000
Option plan vesting period			10 years
Options granted with different vesting terms						5 years
Minimum percentage of total combined voting power of stock						10.00%
Minimum exercise price as percentage of fair market value to holder of more than 10% voting power						110.00%
Minimum exercise price as percentage of fair market value to holder of 10% or less voting power						100.00%
Shares available for future grant						3,348,584
Common stock outstanding						30,101,405
2000 Stock Plan [Member] | Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock option exercisable period			1 year
2000 Stock Plan [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock option exercisable period			2 years
2000 Stock Plan [Member] | Non-employee director [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options exercised, shares					30,000

Stockholders' Equity - 2000 Dir

Stockholders' Equity - 2000 Directors' Stock Option Plan - Additional Information (Detail) - shares	Dec. 31, 2017	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock outstanding	30,301,405	28,463,737
2000 Directors' Stock Option Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock outstanding	200,000

Stockholders' Equity - 2000 Emp

Stockholders' Equity - 2000 Employee Stock Purchase Plan - Additional Information (Detail) - USD ($)	1 Months Ended		12 Months Ended
	Mar. 31, 2015	Apr. 30, 2010	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Jan. 31, 2017	Jan. 31, 2016	Jan. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share available for future grant			3,348,584
Common stock, shares issued			150,837,000	141,297,000
Options granted with exercise prices lower than fair market			$ 0	$ 0	$ 0
Excess tax benefits recognized for tax deductions on stock based compensation			$ 0
Incremental tax benefits recognized from stock options exercised				0
2000 Employee Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Employee stock purchase plan			24 months
Exercise price as percentage of fair market value minimum			85.00%
Stock option increase	350,000	250,000
Extended term of stock plan to the date	10 years	10 years
Plan expiry date			Jun. 30, 2025
Options shares reserved for issuance			2,900,000
Share available for future grant			480,282			1,700,000	1,400,000	1,500,000
Common stock, shares issued			2,419,718
Intrinsic value of options exercised			$ 328,000	$ 158,000	$ 985,000
Weighted-average grant-date fair value of all options granted with exercise prices			$ 0.92	$ 0.81	$ 0.65

Stockholders' Equity - Summary

Stockholders' Equity - Summary of Shares of Common Stock Reserved for Future Issuance (Detail) - shares	Dec. 31, 2017	Jan. 31, 2017	Dec. 31, 2016	Jan. 31, 2016	Jan. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options outstanding	30,301,405		28,463,737
Stock options available for grant	3,348,584
Shares of common stock reserved for future issuance	34,130,271
2000 Employee Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options available for grant	480,282	1,700,000		1,400,000	1,500,000
Shares of common stock reserved for future issuance	480,282

Stockholders' Equity - Summar60

Stockholders' Equity - Summary of Stock Option Activity under all Stock-Based Compensation Plans (Detail) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Outstanding, Number of Options, beginning balance	28,463,737
Options granted, Number of Options	4,660,594
Options exercised, Number of Options	(545,088)
Options forfeited, Number of Options	(285,470)
Options expired, Number of Options	(1,992,368)
Outstanding, Number of Options, ending balance	30,301,405	28,463,737
Exercisable, Number of Options	26,280,797
Vested and expected to vest, Number of Options	30,301,405
Outstanding, Number of Options, Weighted Average Exercise Price Per Share, beginning balance	$ 2.09
Options granted, Weighted Average Exercise Price Per Share	1.33
Options exercised, Weighted Average Exercise Price Per Share	1.03
Options forfeited, Weighted Average Exercise Price Per Share	1.26
Options expired, Weighted Average Exercise Price Per Share	4.06
Outstanding, Number of Options, Weighted Average Exercise Price Per Share, ending balance	1.87	$ 2.09
Exercisable, Number of Options, Weighted Average Exercise Price Per Share	1.96
Vested and expected to vest, Number of Options, Weighted Average Exercise Price Per Share	$ 1.87
Outstanding, Number of Options, Weighted Average Remaining Contractual Term	5 years 2 months 4 days	5 years 1 month 9 days
Exercisable, Number of Options, Weighted Average Remaining Contractual Term	4 years 8 months 8 days
Vested and expected to vest, Number of Options, Weighted Average Remaining Contractual Term	5 years 2 months 4 days
Outstanding, Number of Options, Aggregate Intrinsic Value	$ 0.4	$ 3.9
Exercisable, Number of Options, Aggregate Intrinsic Value	0.4
Vested and expected to vest, Number of Options, Aggregate Intrinsic Value	$ 0.4

Stockholders' Equity - Summar61

Stockholders' Equity - Summary of Employee Stock-Based Compensation Cost that has been Included in Statements of Operations and Comprehensive Loss (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total employee stock-based compensation cost	$ 2,605	$ 2,655	$ 2,660
Cost of product revenues [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total employee stock-based compensation cost	109	106	108
Research and development [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total employee stock-based compensation cost	1,415	1,433	1,400
Selling, general and administrative [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total employee stock-based compensation cost	$ 1,081	$ 1,116	$ 1,152

Stockholders' Equity - Determin

Stockholders' Equity - Determining Fair Value - Additional Information (Detail) - 2000 Employee Stock Purchase Plan [Member] - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected dividend yield in Black-Scholes option valuation model	$ 0
Shares purchased under Company's employee stock purchase plan	122,033	114,025	113,625
Recognition of expenses on shares purchased under employee stock purchase plan	$ 34,000	$ 45,000	$ 62,000
Expected total unrecognized compensation costs related to nonvested stock options	$ 3,000,000
Weighted average term of unrecognized stock-based compensation expense	2 years 2 months 12 days
Cash received from option exercises under stock-based compensation plans	$ 562,000	$ 290,000	$ 1,000,000

Stockholders' Equity - Summar63

Stockholders' Equity - Summary of Assumptions Used to Estimate Fair Value of Options Granted and Shares Purchased (Detail)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Employees Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free rate, minimum	0.60%	0.30%	0.10%
Risk-free rate, maximum	1.30%	0.60%	0.30%
Expected term (in years)	6 months	6 months	6 months
Volatility, minimum	44.00%	65.00%	68.00%
Volatility, maximum	146.00%	81.00%	95.00%
Stock Option Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free rate, minimum	2.00%	1.30%	1.50%
Risk-free rate, maximum	2.50%	2.40%	2.40%
Volatility, minimum	75.00%	76.00%	78.00%
Volatility, maximum	86.00%	83.00%	85.00%
Forfeiture rate	0.00%	4.20%	6.00%
Stock Option Plan [Member] | Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (in years)	6 years 9 months 18 days	6 years 6 months	6 years 6 months
Stock Option Plan [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (in years)	10 years	10 years	10 years

Stockholders' Equity - Summar64

Stockholders' Equity - Summary of Stock Options Outstanding (Detail)	12 Months Ended
	Dec. 31, 2017$ / sharesshares
Range of Exercise Price, $0.73 - $0.88 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options Outstanding, Range of Exercise Price, minimum	$ 0.73
Options Outstanding, Range of Exercise Price, maximum	$ 0.88
Number of Options Outstanding | shares	5,220,108
Options Outstanding, Weighted-Average Remaining Contractual Life(In years)	5 years 8 months 8 days
Options Outstanding, Weighted-Average Exercise Price	$ 0.84
Number of Options Exercisable | shares	4,600,285
Options Exercisable, Weighted-Average Exercise Price	$ 0.83
Range of Exercise Price, $0.93 - $1.16 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options Outstanding, Range of Exercise Price, minimum	0.93
Options Outstanding, Range of Exercise Price, maximum	$ 1.16
Number of Options Outstanding | shares	3,199,479
Options Outstanding, Weighted-Average Remaining Contractual Life(In years)	7 years 7 months 28 days
Options Outstanding, Weighted-Average Exercise Price	$ 1.15
Number of Options Exercisable | shares	2,299,333
Options Exercisable, Weighted-Average Exercise Price	$ 1.15
Range of Exercise Price, $1.19 - $1.20 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options Outstanding, Range of Exercise Price, minimum	1.19
Options Outstanding, Range of Exercise Price, maximum	$ 1.20
Number of Options Outstanding | shares	254,293
Options Outstanding, Weighted-Average Remaining Contractual Life(In years)	7 years 7 months 9 days
Options Outstanding, Weighted-Average Exercise Price	$ 1.19
Number of Options Exercisable | shares	251,793
Options Exercisable, Weighted-Average Exercise Price	$ 1.19
Range of Exercise Price, $1.21 - $1.21 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options Outstanding, Range of Exercise Price, minimum	1.21
Options Outstanding, Range of Exercise Price, maximum	$ 1.21
Number of Options Outstanding | shares	3,390,536
Options Outstanding, Weighted-Average Remaining Contractual Life(In years)	5 years 1 month 6 days
Options Outstanding, Weighted-Average Exercise Price	$ 1.21
Number of Options Exercisable | shares	3,372,536
Options Exercisable, Weighted-Average Exercise Price	$ 1.21
Range of Exercise Price, $1.24 - $1.26 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options Outstanding, Range of Exercise Price, minimum	1.24
Options Outstanding, Range of Exercise Price, maximum	$ 1.26
Number of Options Outstanding | shares	140,938
Options Outstanding, Weighted-Average Remaining Contractual Life(In years)	5 years 1 month 28 days
Options Outstanding, Weighted-Average Exercise Price	$ 1.26
Number of Options Exercisable | shares	140,938
Options Exercisable, Weighted-Average Exercise Price	$ 1.26
Range of Exercise Price, $1.31 - $1.31 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options Outstanding, Range of Exercise Price, minimum	1.31
Options Outstanding, Range of Exercise Price, maximum	$ 1.31
Number of Options Outstanding | shares	3,606,656
Options Outstanding, Weighted-Average Remaining Contractual Life(In years)	8 years 7 months 2 days
Options Outstanding, Weighted-Average Exercise Price	$ 1.31
Number of Options Exercisable | shares	2,020,733
Options Exercisable, Weighted-Average Exercise Price	$ 1.31
Range of Exercise Price, $1.33 - $2.04 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options Outstanding, Range of Exercise Price, minimum	1.33
Options Outstanding, Range of Exercise Price, maximum	$ 2.04
Number of Options Outstanding | shares	2,442,795
Options Outstanding, Weighted-Average Remaining Contractual Life(In years)	7 years 6 months 18 days
Options Outstanding, Weighted-Average Exercise Price	$ 1.49
Number of Options Exercisable | shares	1,686,929
Options Exercisable, Weighted-Average Exercise Price	$ 1.47
Range of Exercise Price, $2.09 - $2.09 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options Outstanding, Range of Exercise Price, minimum	2.09
Options Outstanding, Range of Exercise Price, maximum	$ 2.09
Number of Options Outstanding | shares	3,802,601
Options Outstanding, Weighted-Average Remaining Contractual Life(In years)	4 years 8 months 4 days
Options Outstanding, Weighted-Average Exercise Price	$ 2.09
Number of Options Exercisable | shares	3,683,939
Options Exercisable, Weighted-Average Exercise Price	$ 2.09
Range of Exercise Price, $2.13 - $3.11 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options Outstanding, Range of Exercise Price, minimum	2.13
Options Outstanding, Range of Exercise Price, maximum	$ 3.11
Number of Options Outstanding | shares	4,767,668
Options Outstanding, Weighted-Average Remaining Contractual Life(In years)	2 years 21 days
Options Outstanding, Weighted-Average Exercise Price	$ 2.61
Number of Options Exercisable | shares	4,747,980
Options Exercisable, Weighted-Average Exercise Price	$ 2.61
Range of Exercise Price, $3.26 - $6.29 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options Outstanding, Range of Exercise Price, minimum	3.26
Options Outstanding, Range of Exercise Price, maximum	$ 6.29
Number of Options Outstanding | shares	3,476,331
Options Outstanding, Weighted-Average Remaining Contractual Life(In years)	1 year 7 months 28 days
Options Outstanding, Weighted-Average Exercise Price	$ 4.39
Number of Options Exercisable | shares	3,476,331
Options Exercisable, Weighted-Average Exercise Price	$ 4.39
Range of Exercise Price, $0.73 - $6.29 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options Outstanding, Range of Exercise Price, minimum	0.73
Options Outstanding, Range of Exercise Price, maximum	$ 6.29
Number of Options Outstanding | shares	30,301,405
Options Outstanding, Weighted-Average Remaining Contractual Life(In years)	5 years 2 months 4 days
Options Outstanding, Weighted-Average Exercise Price	$ 1.87
Number of Options Exercisable | shares	26,280,797
Options Exercisable, Weighted-Average Exercise Price	$ 1.96

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Contingency [Line Items]
Deferred tax liability		$ 244,000	$ 397,000
Deferred tax assets		244,000
Deferred income tax provision		(153,000)	$ 0	$ (8,000)
Total income tax provision (benefit) expense		$ (150,000)		53,000
Income tax expenses related to unrealized gain on a marketable equity security				$ 61,000
Statutory federal income tax rate		34.00%	34.00%	34.00%
Increase (decrease) in valuation allowance of net deferred tax assets		$ (43,100,000)	$ 11,400,000	$ 7,200,000
Unrecognized tax benefits		7,849,000	6,982,000	6,965,000
Interest and penalty expense related to unrecognized tax benefits		0	0	0
Provisional amount related to re-measurement of deferred tax balance due to Tax Cut and Jobs Act		43,100,000
Scenario Forecast [Member]
Income Tax Contingency [Line Items]
Statutory federal income tax rate	21.00%
Federal [Member]
Income Tax Contingency [Line Items]
Net operating loss carryforwards for income tax purposes		$ 327,100,000
Tax carryforwards expire date		2019 through 2036
Research [Member] | Federal [Member]
Income Tax Contingency [Line Items]
Tax carryforwards expire date		2018 through 2037
Research and development tax credits		$ 12,500,000
Interest and other income, net [Member]
Income Tax Contingency [Line Items]
Total income tax provision (benefit) expense		(150,000)	$ 0	$ 53,000
State [Member]
Income Tax Contingency [Line Items]
Total income tax provision (benefit) expense		3,000
Net operating loss carryforwards for income tax purposes		$ 204,900,000
Tax carryforwards expire date		2028 through 2036
State [Member] | Research [Member]
Income Tax Contingency [Line Items]
Research and development tax credits		$ 13,700,000

Income Taxes - Reconciliation o

Income Taxes - Reconciliation of Income Tax Expenses (Benefit) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Effective Income Tax Rate Reconciliation, Amount [Abstract]
U.S. federal taxes benefit at statutory rate	$ (1,307)	$ (11,733)	$ (7,681)
State taxes	3	0	0
Change in valuation allowance	(41,865)	10,847	7,725
Stock-based compensation	1,832	2,045	530
Change in deferreds	12	(3)	56
Deferred Tax Remeasurement	42,528
Other	(1,353)	$ (1,156)	(577)
Total income tax (benefit) provision	$ (150)		$ 53

Income Taxes - Summary of Compo

Income Taxes - Summary of Components of Company's Deferred Tax Assets (Detail) - USD ($)	Dec. 31, 2017	Dec. 31, 2016
Deferred tax assets:
Net operating loss carryforwards	$ 82,369,000	$ 123,107,000
Research and other credits	16,303,000	13,441,000
Capitalized research and development expenses		10,000
Deferred revenue	395,000	874,000
Stock-based compensation	5,053,000	8,693,000
Other	2,261,000	3,405,000
Total deferred tax assets	106,381,000	149,530,000
Valuation allowance for deferred tax assets	(106,381,000)	(149,530,000)
Deferred tax liabilities—Intangibles	(244,000)	(397,000)
Net deferred tax liabilities	$ (244,000)	$ (397,000)

Income Taxes - Reconciliation68

Income Taxes - Reconciliation of Unrecognized Tax Benefits (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Balance at beginning of the year	$ 6,982	$ 6,965
Decreased related to prior year tax positions		(737)
Increased related to current year tax positions	867	754
Settlements		0
Reductions due to lapse of applicable statute of limitations		0
Balance at end of the year	$ 7,849	$ 6,982

Unaudited Selected Quarterly 69

Unaudited Selected Quarterly Financial Data - Selected Quarterly Financial Data (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Quarterly Financial Data [Abstract]
Revenue	$ 19,538	$ 20,746	$ 4,319	$ 4,567	$ 3,517	$ 3,743	$ 3,157	$ 3,608	$ 49,170	$ 14,025	$ 19,124
Net income (loss)	$ 8,235	$ 6,111	$ (9,927)	$ (8,114)	$ (8,811)	$ (8,832)	$ (9,014)	$ (7,852)	$ (3,695)	$ (34,509)	$ (22,663)
Basic net income (loss) per share	$ 0.06	$ 0.04	$ (0.07)	$ (0.06)	$ (0.06)	$ (0.06)	$ (0.07)	$ (0.06)	$ (0.03)	$ (0.26)	$ (0.19)
Diluted net income (loss) per share	$ 0.05	$ 0.04	$ (0.07)	$ (0.06)	$ (0.06)	$ (0.06)	$ (0.07)	$ (0.06)	$ (0.03)	$ (0.26)	$ (0.19)

Subsequent Events - Additional

Subsequent Events - Additional Information (Detail) - USD ($) $ / shares in Units, shares in Millions	Mar. 02, 2018	Feb. 28, 2018	Jul. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Subsequent Event [Line Items]
Proceeds from sale of common stock, net of commission				$ 11,989,000	$ 23,745,000	$ 14,290,000
Oxford Finance 2016 Term Loan [Member]
Subsequent Event [Line Items]
First principal payment date			Mar. 1, 2018
Percentage of an additional payment equal to principal amount			9.25%
Subsequent Event [Member]
Subsequent Event [Line Items]
Proceeds from sale of common stock, net of commission	$ 2,800,000
Sale of common stock during period	2.5
Common stock weighted average price	$ 1.17
Securities offered	$ 67,800,000
Subsequent Event [Member] | Oxford Finance 2016 Term Loan [Member]
Subsequent Event [Line Items]
First principal payment date		Dec. 1, 2018
Loan modification fee		$ 100,000
Percentage of an additional payment equal to principal amount		10.00%
Cantor Fitzgerald Co [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Securities offered	$ 14,900,000

Schedule II-Valuation and Qua71

Schedule II-Valuation and Qualifying Accounts (Detail) - Allowance for doubtful accounts [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at beginning of the year	$ 73	$ 161	$ 211
Additions (Reduction) to allowances	165	(70)	(38)
Deductions	(83)	(18)	(12)
Balance at end of the year	$ 155	$ 73	$ 161