DURECT (DRRX) 10-Q 5 Nov 19 2019 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2019	Oct. 30, 2019
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2019
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q3
Title of 12(b) Security	Common Stock $0.0001 par value per share Preferred Share Purchase Rights
Security Exchange Name	NASDAQ
Entity Interactive Data Current	Yes
Trading Symbol	DRRX
Entity Registrant Name	DURECT CORP
Entity Central Index Key	0001082038
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Common Stock, Shares Outstanding		192,362,179
Entity Shell Company	false
Entity Incorporation, State or Country Code	DE
Entity File Number	000-31615
Entity Tax Identification Number	94-3297098
Entity Address, Address Line One	10260 Bubb Road
Entity Address, City or Town	Cupertino
Entity Address, State or Province	CA
Entity Current Reporting Status	Yes
Entity Address, Postal Zip Code	95014
City Area Code	408
Local Phone Number	777-1417
Document Quarterly Report	true
Document Transition Report	false

Condensed Balance Sheets

Condensed Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 39,726	$ 31,644
Short-term investments	17,235	2,671
Accounts receivable (net of allowances of $74 at September 30, 2019 and $102 at December 31, 2018)	12,193	1,757
Inventories, net	3,618	3,421
Prepaid expenses and other current assets	970	2,247
Total current assets	73,742	41,740
Property and equipment, net	462	605
Operating lease right-of-use assets	6,397
Goodwill	6,399	6,399
Long-term restricted investments	150	150
Other long-term assets	1,107	1,105
Total assets	88,257	49,999
Current liabilities:
Accounts payable	1,501	1,589
Accrued liabilities	4,512	4,668
Contract research liabilities	2,089	1,405
Deferred revenue, current portion	27,582
Term loan, current portion, net	2,981
Operating lease liabilities, current portion	2,028
Total current liabilities	40,693	7,662
Deferred revenue, non-current portion	2,033	812
Operating lease liabilities, non-current portion	4,836
Term loan, non-current portion, net	17,970	20,533
Other long-term liabilities	719	992
Commitments and contingencies
Stockholders’ equity:
Common stock	19	16
Additional paid-in capital	506,956	488,608
Accumulated other comprehensive loss	2
Accumulated deficit	(484,971)	(468,624)
Stockholders’ equity	22,006	20,000
Total liabilities and stockholders’ equity	$ 88,257	$ 49,999

Condensed Balance Sheets (Paren

Condensed Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Statement Of Financial Position [Abstract]
Allowances for accounts receivable	$ 74	$ 102

Condensed Statements of Compreh

Condensed Statements of Comprehensive Loss - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Total revenues	$ 10,763	$ 8,036	$ 18,879	$ 14,937
Operating expenses:
Cost of product revenues	$ 731	$ 912	$ 2,746	$ 3,170
Type of cost, good or service [extensible list]	us-gaap:ProductMember	us-gaap:ProductMember	us-gaap:ProductMember	us-gaap:ProductMember
Research and development	$ 7,906	$ 6,542	$ 20,755	$ 19,614
Selling, general and administrative	3,837	2,870	10,569	8,880
Total operating expenses	12,474	10,324	34,070	31,664
Loss from operations	(1,711)	(2,288)	(15,191)	(16,727)
Other income (expense):
Interest and other income	350	234	736	632
Interest expense	(629)	(661)	(1,892)	(1,928)
Net other expense	(279)	(427)	(1,156)	(1,296)
Net loss	(1,990)	(2,715)	(16,347)	(18,023)
Net change in unrealized loss on available-for-sale securities, net of reclassification adjustments and taxes	9		2	1
Total comprehensive loss	$ (1,981)	$ (2,715)	$ (16,345)	$ (18,022)
Net loss per share
Basic	$ (0.01)	$ (0.02)	$ (0.09)	$ (0.11)
Diluted	$ (0.01)	$ (0.02)	$ (0.09)	$ (0.11)
Weighted-average shares used in computing net loss per share
Basic	192,039	162,002	172,939	159,091
Diluted	192,039	162,002	172,939	159,091
Collaborative Research and Development and Other Revenue [Member]
Total revenues	$ 7,741	$ 5,691	$ 10,880	$ 7,432
Product Revenue, Net [Member]
Total revenues	$ 3,022	$ 2,345	$ 7,999	$ 7,505

Condensed Statements of Stockho

Condensed Statements of Stockholders' Equity - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock [Member]	Additional paid-in capital [Member]	Accumulated other comprehensive income (loss) [Member]	Accumulated deficit [Member]
Beginning balance at Dec. 31, 2017	$ 21,488	$ 15	$ 465,246	$ (1)	$ (443,772)
Beginning balance, shares at Dec. 31, 2017		150,837
Adjustment due to changes in accounting policies	470				470
Issuance of common stock upon exercise of stock options	565		565
Issuance of common stock upon exercise of stock options, Shares		515
Issuance of common stock upon exercise of stock options and ESPP purchase	1,860		1,860
Issuance of common stock upon equity financings, net of issuance costs	13,646	$ 1	13,645
Issuance of common stock upon equity financings, net of issuance cost, shares		8,171
Stock-based compensation expense from stock options and ESPP shares	663		663
Net loss	(8,297)				(8,297)
Ending balance at Mar. 31, 2018	30,395	$ 16	481,979	(1)	(451,599)
Ending balance, shares at Mar. 31, 2018		159,523
Beginning balance at Dec. 31, 2017	21,488	$ 15	465,246	(1)	(443,772)
Beginning balance, shares at Dec. 31, 2017		150,837
Net loss	(18,023)
Ending balance at Sep. 30, 2018	26,094	$ 16	487,403		(461,325)
Ending balance, shares at Sep. 30, 2018		162,001
Beginning balance at Mar. 31, 2018	30,395	$ 16	481,979	(1)	(451,599)
Beginning balance, shares at Mar. 31, 2018		159,523
Issuance of common stock upon exercise of stock options and ESPP purchase	1,111		1,111
Issuance of common stock upon exercise of stock options and ESPP purchase, shares		1,020
Issuance of common stock upon equity financings, net of issuance costs	3,134		3,134
Issuance of common stock upon equity financings, net of issuance cost, shares		1,458
Stock-based compensation expense from stock options and ESPP shares	639		639
Net loss	(7,011)				(7,011)
Change in unrealized loss on available-for-sale securities, net of tax	1			1
Ending balance at Jun. 30, 2018	28,269	$ 16	486,863		(458,610)
Ending balance, shares at Jun. 30, 2018		162,001
Stock-based compensation expense from stock options and ESPP shares	540		540
Net loss	(2,715)				(2,715)
Ending balance at Sep. 30, 2018	26,094	$ 16	487,403		(461,325)
Ending balance, shares at Sep. 30, 2018		162,001
Beginning balance at Dec. 31, 2018	20,000	$ 16	488,608		(468,624)
Beginning balance, shares at Dec. 31, 2018		162,060
Issuance of common stock upon equity financings, net of issuance costs	61		61
Issuance of common stock upon equity financings, net of issuance cost, shares		243
Stock-based compensation expense from stock options and ESPP shares	437		437
Fully vested options issued to settle accrued liabilities	994		994
Net loss	(7,130)				(7,130)
Change in unrealized loss on available-for-sale securities, net of tax	(4)			(4)
Ending balance at Mar. 31, 2019	14,358	$ 16	490,100	(4)	(475,754)
Ending balance, shares at Mar. 31, 2019		162,303
Beginning balance at Dec. 31, 2018	20,000	$ 16	488,608		(468,624)
Beginning balance, shares at Dec. 31, 2018		162,060
Net loss	(16,347)
Ending balance at Sep. 30, 2019	22,006	$ 19	506,956	2	(484,971)
Ending balance, shares at Sep. 30, 2019		192,243
Beginning balance at Mar. 31, 2019	14,358	$ 16	490,100	(4)	(475,754)
Beginning balance, shares at Mar. 31, 2019		162,303
Issuance of common stock upon equity financings, net of issuance costs	15,319	$ 3	15,316
Issuance of common stock upon equity financings, net of issuance cost, shares		29,571
Issuance of common stock upon ESPP purchases	27		27
Issuance of common stock upon ESPP purchases, shares		57
Stock-based compensation expense from stock options and ESPP shares	420		420
Net loss	(7,227)				(7,227)
Change in unrealized loss on available-for-sale securities, net of tax	(3)			(3)
Ending balance at Jun. 30, 2019	22,894	$ 19	505,863	(7)	(482,981)
Ending balance, shares at Jun. 30, 2019		191,931
Issuance of common stock upon ESPP purchases	241		241
Issuance of common stock upon ESPP purchases, shares		312
Stock-based compensation expense from stock options and ESPP shares	852		852
Net loss	(1,990)				(1,990)
Change in unrealized loss on available-for-sale securities, net of tax	9			9
Ending balance at Sep. 30, 2019	$ 22,006	$ 19	$ 506,956	$ 2	$ (484,971)
Ending balance, shares at Sep. 30, 2019		192,243

Condensed Statements of Stock_2

Condensed Statements of Stockholders' Equity (Parenthetical) - USD ($) $ in Thousands	3 Months Ended
	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2018	Mar. 31, 2018
Statement Of Stockholders Equity [Abstract]
Stock issuance costs	$ 127	$ 129	$ 97	$ 469

Condensed Statements of Cash Fl

Condensed Statements of Cash Flows - USD ($) $ in Thousands		9 Months Ended
		Sep. 30, 2019	Sep. 30, 2018
Cash flows from operating activities
Net loss		$ (16,347)	$ (18,023)
Adjustments to reconcile net loss to net cash used in by operating activities:
Depreciation and amortization		224	162
Stock-based compensation		1,709	1,839
Amortization of debt issuance cost		271	228
Net amortization on investments		42	80
Changes in operating lease liabilities		105	70
Changes in assets and liabilities:
Accounts receivable		(10,436)	770
Inventories		(198)	(547)
Prepaid expenses and other assets		1,275	101
Accounts payable		(88)	(368)
Accrued and other liabilities		1,080	1,975
Contract research liabilities		684	541
Deferred revenue		28,803	(479)
Total adjustments		23,471	4,372
Net cash provided by (used in) operating activities		7,124	(13,651)
Cash flows from investing activities
Purchases of property and equipment		(81)	(73)
Purchases of available-for-sale securities		(17,306)	(6,893)
Proceeds from maturities of available-for-sale securities		2,702	11,118
Net cash (used in) provided by investing activities		(14,685)	4,152
Cash flows from financing activities
Payments on equipment financing obligations		(6)	(10)
Payment of additional issuance cost for term loan			(105)
Net proceeds from issuances of common stock		15,649	18,456
Net cash provided by financing activities		15,643	18,341
Net decrease in Cash, cash equivalents, and restricted cash		8,082	8,842
Cash, cash equivalents, and restricted cash, beginning of the period		31,794	29,525
Cash, cash equivalents, and restricted cash, end of the period	[1]	39,876	38,367
Supplementary disclosure of non-cash financing information
Fully vested options issued to settle accrued liabilities		994	$ 1,860
Operating lease right-of-use assets obtained in exchange for operating lease obligations	[2]	$ 7,329
[1]	Includes restricted cash of $150,000 (in long term restricted investments) included in the condensed balance sheets at both September 30, 2019 and 2018.
[2]	Amounts for the nine months ended September 30, 2019 include the transition adjustment for the adoption of Accounting Standards Update (“ASU”) No. 2016-02, Leases (Topic 842) (“Topic 842”).

Condensed Statement of Cash Flo

Condensed Statement of Cash Flows (Parenthetical) - USD ($)	Sep. 30, 2019	Sep. 30, 2018
Long Term Restricted Investments [Member]
Restricted cash	$ 150,000	$ 150,000

Summary of Significant Accounti

Summary of Significant Accounting Policies	9 Months Ended
	Sep. 30, 2019
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Note 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 the Company’s 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) proprietary pharmaceutical 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 These financial statements have been prepared in accordance with the rules and regulations of the Securities and Exchange Commission (SEC), and therefore do not include all the information and footnotes necessary for a complete presentation of the Company’s results of operations, financial position and cash flows in conformity with U.S. generally accepted accounting principles (U.S. GAAP). The unaudited financial statements reflect all adjustments (consisting only of normal recurring adjustments) which are, in the opinion of management, necessary for a fair presentation of the financial position at September 30, 2019, the operating results and comprehensive loss for the three and nine months ended September 30, 2019 and 2018, stockholders’ equity for the three and nine months ended September 30, 2019 and 2018, and cash flows for the nine months ended September 30, 2019 and 2018. The balance sheet as of December 31, 2018 has been derived from audited financial statements at that date but does not include all of the information and footnotes required by U.S. GAAP for complete financial statements. These financial statements and notes should be read in conjunction with the Company’s audited financial statements and notes thereto, included in the Company’s annual report on Form 10-K for the fiscal year ended December 31, 2018 filed with the SEC. The results of operations for the interim periods presented are not necessarily indicative of results that may be expected for any other interim period or for the full fiscal year. Liquidity and Need to Raise Additional Capital As of September 30, 2019, the Company had an accumulated deficit of $485.0 million as well as negative cash flows from operating activities for the nine months ended September 30, 2019. 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. Inventories Inventories are stated at the lower of cost or net realizable value, with cost determined on a first-in, first-out basis. The Company may be required to expense previously capitalized inventory costs upon a change in management’s judgment due to, among other potential factors, a denial or delay of approval of a customer’s product by the necessary regulatory bodies, or new information that suggests that the inventory will not be saleable. 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 consist of the following (in thousands): September 30, 2019 December 31, 2018 (unaudited) Raw materials $ 276 $ 223 Work in process 1,362 1,486 Finished goods 1,980 1,712 Total inventories $ 3,618 $ 3,421 Leases Effective January 1, 2019, the Company adopted Topic 842 using the modified retrospective transition method approach with a cumulative-effect adjustment as of January 1, 2019 in accordance with ASU No. 2018-11, Leases (Topic 842) - Targeted Improvements. Results for the nine months ended September 30, 2019 are presented under Topic 842. Other prior period amounts are not adjusted and continue to be reported in accordance with our historic accounting under previous lease guidance, ASC Topic 840: Leases (Topic 840). The Company elected the package of practical expedients permitted under the transition guidance within the new standard, which among other things, allowed the Company to carry forward the historical lease classification of those leases in place as of January 1, 2019. The adjustments due to the adoption of Topic 842 primarily related to the recognition of an operating lease right-of-use asset and operating lease liability for our leased properties. The impact of the adoption of Topic 842 on the accompanying Condensed Balance Sheet as of January 1, 2019 was as follows (in thousands): As of January 1, 2019 December 31, 2018 Adjustments Due to the Adoption of Topic 842 January 1, 2019 Condensed Balance Sheets Operating lease right-of-use assets $ — $ 7,329 $ 7,329 Operating lease liabilities: Accrued liabilities (1) $ (92 ) $ 92 $ — Other long-term liabilities (1) (270 ) 270 — Lease liabilities, current portion — (1,972 ) (1,972 ) Lease liabilities, non-current portion — (5,719 ) (5,719 ) $ (362 ) $ (7,329 ) $ (7,691 ) (1) Includes deferred rent, current and long-term portions of operating lease liabilities which were recorded against the operating lease right-of-use asset upon adoption of Topic 842 There was no effect from the adoption of Topic 842 on the Company’s condensed statement of cash flows. Revenue Recognition The Company enters into license and collaboration agreements under which the Company may receive upfront license fees, research funding and contingent milestone payments and royalties. Effective January 1, 2018, the Company adopted FASB ASC Topic 606, Revenue from Contracts with Customers, or ASC 606. In accordance with ASC 606, the Company changed certain characteristics of its revenue recognition accounting policy as described below. ASC 606 was applied using the modified retrospective method, where the cumulative effect of the initial application was recognized as an adjustment to opening retained earnings at January 1, 2018. The Company recorded a net increase to opening retained earnings of $470,000 with an offset entry to a contra liability account as of January 1, 2018 due to the cumulative impact of adopting Topic 606, with the impact relating to the Company’s deferred collaborative research and development revenues. There was no impact to reported total assets, revenues and operating expenses for the three and nine months ended September 30, 2019 as a result of applying Topic 606. Product Revenue, Net The Company 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. Revenues from product sales are recognized when the customer obtains control of the Company’s product, which occurs at a point in time, typically upon shipment to the customer. The Company expenses incremental costs of obtaining a contract as and when incurred if the expected amortization period of the asset that the Company would have recognized is one year or less. Trade Discounts and Allowances: The Company provides certain customers with discounts that are explicitly stated in the Company’s contracts and are recorded as a reduction of revenue in the period the related product revenue is recognized. Product Returns: Consistent with industry practice, the Company generally offers customers a limited right of return for products that have been purchased from the Company. The Company estimates the amount of its product sales that may be returned by its customers and records this estimate as a reduction of revenue in the period the related product revenue is recognized. The Company currently estimates product return liabilities using its historical sales information. The Company expects product returns to be minimal. Collaborative Research and Development and Other Revenue The Company enters into license agreements which are within the scope of Topic 606, under which it licenses certain rights to its product candidates to third parties. The terms of these arrangements typically include payment to the Company of one or more of the following: non-refundable, up-front license fees; reimbursement of development costs incurred by the Company under approved work plans; development, regulatory and commercial milestone payments; payments for manufacturing supply services the Company provides through its contract manufacturers; and royalties on net sales of licensed products. Each of these payments results in collaborative research and development revenues, except for revenues from royalties on net sales of licensed products, which are classified as royalty revenues. In determining the appropriate amount of revenue to be recognized as it fulfills its obligations under each of its agreements, the Company performs the following steps: (i) identification of the promised goods or services in the contract; (ii) determination of whether the promised goods or services are performance obligations including whether they are distinct in the context of the contract; (iii) measurement of the transaction price, including the constraint on variable consideration; (iv) allocation of the transaction price to the performance obligations; and (v) recognition of revenue when (or as) the Company satisfies each performance obligation. As part of the accounting for these arrangements, the Company must develop assumptions that require judgment to determine the stand-alone selling price for each performance obligation identified in the contract. The Company uses key assumptions to determine the standalone selling price, which may include forecasted revenues, development timelines, reimbursement rates for personnel costs, discount rates and probabilities of technical and regulatory success. The Company expects to recognize revenue for the variable consideration currently being constrained when it is probable that a significant revenue reversal will not occur. Licenses of intellectual property: If the license to the Company’s intellectual property is determined to be distinct from the other performance obligations identified in the arrangement, the Company recognizes revenues from non-refundable, up-front fees allocated to the license when the license is transferred to the customer and the customer is able to use and benefit from the license. For licenses that are bundled with other promises, the Company utilizes judgment to assess the nature of the combined performance obligation to determine whether the combined performance obligation is satisfied over time or at a point in time and, if over time, the appropriate method of measuring progress for purposes of recognizing revenue from non-refundable, up-front fees. The Company evaluates the measure of progress each reporting period and, if necessary, adjusts the measure of performance and related revenue recognition. Milestone Payments: At the inception of each arrangement that includes development milestone payments, the Company evaluates whether the milestones are considered probable of being reached and estimates the amount to be included in the transaction price using the most likely amount method. If it is probable that a significant revenue reversal would not occur, the associated milestone value is included in the transaction price. Milestone payments that are not within the control of the Company or the licensee, such as regulatory approvals, are not considered probable of being achieved until those approvals are received. The transaction price is then allocated to each performance obligation on a relative stand-alone selling price basis, for which the Company recognizes revenue as or when the performance obligations under the contract are satisfied. At the end of each subsequent reporting period, the Company re-evaluates the probability of achievement of such development milestones and any related constraint, and if necessary, adjusts its estimate of the overall transaction price. Any such adjustments are recorded on a cumulative catch-up basis, which would affect collaborative research and development revenues and net income (loss) in the period of adjustment. Manufacturing Supply Services: Arrangements that include a promise for future supply of drug product for either clinical development or commercial supply at the customer’s discretion are generally considered as options. The Company assesses if these options provide a material right to the customer and if so, they are accounted for as separate performance obligations. If the Company is entitled to additional payments when the customer exercises these options, any additional payments are recorded in collaborative research and development revenue when the customer obtains control of the goods, which is upon delivery. Royalties and Earn-outs: For arrangements that include sales-based royalties or earn-outs, including milestone payments based on the level of sales, and the license is deemed to be the predominant item to which the royalties relate, the Company recognizes revenue at the later of (i) when the related sales occur, or (ii) when the performance obligation to which some or all of the royalty has been allocated has been satisfied (or partially satisfied). To date, the Company has not recognized any material royalty revenue resulting from the Company’s collaborative arrangements or material earn-out revenue from the Company’s patent purchase agreement with Indivior. The Company receives payments from its customers based on development cost schedules established in each contract. Up-front payments are recorded as deferred revenue upon receipt or when due, and may require deferral of revenue recognition to a future period until the Company performs its obligations under these arrangements. Amounts are recorded as accounts receivable when the Company’s right to consideration is unconditional. The Company does not assess whether a contract has a significant financing component if the expectation at contract inception is such that the period between payment by the customer and the transfer of the promised goods or services to the customer will be one year or less. Total revenue by geographic region for the three and nine months ended September 30, 2019 and 2018 are as follows (in thousands): Three months ended September 30, Nine months ended September 30, 2019 2018 2019 2018 United States $ 8,977 $ 1,931 $ 14,331 $ 6,129 Europe 721 5,585 2,104 7,088 Japan 425 149 1,161 722 Other 640 371 1,283 998 Total $ 10,763 $ 8,036 $ 18,879 $ 14,937 Comprehensive Loss Components of other comprehensive 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. 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): Nine months ended September 30, 2019 2018 Numerators: Net loss $ (16,347 ) $ (18,023 ) Denominator: Weighted average shares used to compute basic net loss per share 172,939 159,091 Dilutive common shares from stock options and ESPP — — Weighted average shares used to compute diluted net loss per share 172,939 159,091 Net loss per share: Basic $ (0.09 ) $ (0.11 ) Diluted $ (0.09 ) $ (0.11 ) Options to purchase approximately 12.2 million and 26.2 million shares of common stock were excluded from the denominator in the calculation of diluted net loss per share for the three and nine months ended September 30, 2019, respectively, as the effect would be anti-dilutive. Options to purchase approximately 17.2 million and 15.6 million shares of common stock were excluded from the denominator in the calculation of diluted net loss per share for the three and nine months ended September 30, 2018, respectively, as the effect would be anti-dilutive. Recently Adopted Accounting Standards In February 2016, the FASB issued ASU 2016-02, Leases (Topic 842) In June 2018, the FASB issued Accounting Standards Update (“ASU”) No. 2018-07, Compensation – Stock Compensation (Topic 718) In February 2018, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2018-02, “Income Statement – Reporting Comprehensive Income (Topic 220): Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income.” Recently Issued Accounting Standards In November 2018, the Financial Accounting Standards Board (the FASB) issued ASU No. 2018-18, Collaborative Arrangements (Topic 808): Clarifying the Interaction between Topic 808 and Topic 606 (ASU 2018-18) In August 2018, the FASB issued Accounting Standards Update (“ASU”) 2018-13 , Fair Value Measurement (Topic 820): Disclosure Framework – Changes to the Disclosure Requirements for Fair Value Measurement which eliminates certain disclosure requirements for fair value measurements for all entities, requires public entities to disclose certain new information and modifies some disclosure requirements. fiscal years In January 2017, the FASB issued ASU No. 2017-04, Intangibles—Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment, (ASU 2017-04) In June 2016, the FASB issued Accounting Standards Update No. 2016-13 (ASU 2016-13) “Financial Instruments - Credit Losses: Measurement of Credit Losses on Financial Instruments.” ASU 2016-13 requires measurement and recognition of expected credit losses for financial assets. This standard is effective for fiscal years beginning after December 15, 2019, including interim reporting periods within those years and must be adopted using a modified retrospective approach, with certain exceptions. Early adoption is permitted. The Company does not expect the adoption of this standard to have a material effect on its financial statements.

Strategic Agreements

Strategic Agreements	9 Months Ended
	Sep. 30, 2019
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Strategic Agreements	Note 2. Strategic Agreements The collaborative research and development and other revenues associated with the Company’s collaborators or counterparties are as follows (in thousands): Three months ended September 30, Nine months ended September 30, 2019 2018 2019 2018 Collaborator/Counterparty Gilead (1) $ 7,416 $ 585 $ 10,120 $ 1,892 Others (2) 325 5,106 760 5,540 Total collaborative research and development and other revenue $ 7,741 $ 5,691 $ 10,880 $ 7,432 (1) Non-feasibility related amounts were from the partial recognition of the upfront license fee and milestone payment which was $6.2 million for each of the three and nine months ended September 30, 2019, compared to zero for the corresponding periods in 2018. The Company signed a license agreement with Gilead on July 19, 2019. (2) Includes: (a) amounts related to earn-out revenue from Indivior UK Limited (Indivior) with respect to PERSERIS net sales as well as a $5.0 million milestone payment earned in from Indivior in 2018; (b) other feasibility program(s); and (c) research and development activities funded by Santen pharmaceutical Co. Ltd. (Santen). Note that in January 2018, we were notified by Santen that due to a shift in near term priorities, Santen has elected to reallocate research and development resources and put our program on pause until further notice. While the main program is on pause, the parties are working together on a limited set of research and development activities funded by Santen. Agreement with Gilead Sciences, Inc. On July 19, 2019, the Company entered into a license agreement (the “Gilead Agreement”) with Gilead Sciences, Inc. (“Gilead”). Pursuant to the Gilead Agreement, the Company has granted Gilead the exclusive worldwide rights to develop and commercialize a long-acting injectable HIV product utilizing DURECT’s SABER ® Under the terms of the Gilead Agreement, Gilead made an upfront payment to DURECT of $25 million, with the potential for up to an additional $75 million in development and regulatory milestones, up to an additional $70 million in sales-based milestones, as well as tiered single-digit royalties on product sales for a defined period. Gilead has the exclusive option to license additional SABER-based products directed to HIV and HBV for up to an additional $150 million per product in upfront, development, regulatory and sales-based milestones as well as tiered single-digit royalties on sales. In September 2019, the Company also earned the right to receive a $10 million milestone payment from Gilead for further development of the product candidate; this payment was received in October 2019. The parties will collaborate on specified development activities with Gilead controlling and funding the development programs. The Gilead Agreement contains customary representations, warranties and indemnification provisions. The term of the Gilead Agreement is for the duration of Gilead’s obligation to pay royalties for product sales under the Gilead Agreement. The Gilead Agreement provides each party with specified termination rights, including the right of Gilead to terminate at will with advance notice to DURECT and each party to terminate the Gilead Agreement upon material breach of the Gilead Agreement by the other party. The Company assessed the Gilead Agreement and concluded that Gilead is a customer. The Company evaluated the promised goods and services in the contract and concluded that it had two performance obligations. The first performance obligation, expected to be completed and delivered by December 31, 2020, consists of a bundle of the exclusive licenses to the HIV product candidate and exclusive access to the SABER platform for use in the fields of HIV and HBV, the research, development and manufacturing services through completion of technology transfer ( the primary services ), participation in the joint development committee and initial supply of the related materials. None of these goods and services were distinct as they are highly interdependent and each represents an input into the process through which Gilead will be able to derive the full benefits from the licensed intellectual property. The additional research and development services after technology transfer is complete are distinct, as these services are not essential for Gilead, and will be accounted for as the second performance obligation. The Company also evaluated Gilead’s rights to license additional SABER-based products and concluded that these are option rights, are at market rates, and do not constitute a material right performance obligation. As such, these options have been excluded from the initial allocation of transaction price and the Company will account for them as separate contracts when and if Gilead elects to exercise each option right. As the reimbursement amounts for research and development costs approximate the value of the Company’s involvement in research and development, the Company allocated these amounts to the related performance obligations. The remaining amounts of the transaction price are associated primarily with the value of the licenses to intellectual property, and were allocated to the bundled performance obligation that includes the licenses. The Company recognizes revenue from the first performance obligation and will recognize revenue from the second performance obligation over the respective performance periods using the cost-to-cost input method, which it believes best depicts the transfer of control to the customer. Under the cost-to-cost input method, the extent of progress towards completion is measured based on the ratio of actual costs incurred to the total estimated costs. Revenue is recorded as a percentage of the transaction price based on the extent of progress towards completion. The estimate of the Company ’ During the three and nine months ended September 30, 2019, the Company received a $25.0 million non-refundable upfront fee from Gilead and allocated this amount plus the $10.0 million of milestone payment earned in September 2019 and received from Gilead in October 2019, to the first identified performance obligation through the primary services using the cost-to-cost input method allowable under ASC 606. The Company applies the practical expedient in Topic 606 and does not include disclosures regarding amounts for variable consideration allocated to wholly-unsatisfied performance obligations or wholly-unsatisfied distinct goods that form part of a single performance obligation, if any. This variable consideration includes expected reimbursement of research and development costs. During the three month and nine month periods ended September 30, 2019, the Company recognized $6.2 million of the deferred revenue within collaborative research and development and other revenues. The Company also recognized $1.2 million and $3.9 million, respectively, from Gilead during the three month and nine-month periods ended September 30, 2019 from feasibility related collaborative research and development services. As of September 30, 2019, the Company expects to recognize the remaining $28.8 million in deferred revenue associated with the $25.0 million non-refundable upfront fee and the $10.0 million milestone payment over the estimated research and development period using the cost-to-cost input method over an estimated period of approximately 1.25 years. The following table presents changes in the Company’s contract assets and liabilities for the nine months ended September 30, 2019 (in thousands): Balance at July 1, 2019 Additions Deletions Balance at September 30, 2019 Condensed Balance Sheets Assets Accounts receivable $ — $ 35,901 $ (25,231 ) $ 10,670 Total contract asset $ — $ 35,901 $ (25,231 ) $ 10,670 Liabilities Deferred revenue, current portion $ — $ 33,779 $ (6,198 ) $ 27,581 Deferred revenue, non-current portion $ — $ 1,221 $ — $ 1,221 Total contract liabilities $ — $ 35,000 $ (6,198 ) $ 28,802 Patent Purchase Agreement with Indivior On September 26, 2017, the Company entered into a Patent Purchase Agreement (the “Indivior Agreement”) with Indivior. Pursuant to the Indivior Agreement, the Company assigned to Indivior certain patents that may provide further intellectual property protection for PERSERIS™ (risperidone), Indivior’s extended-release injectable suspension for the treatment of schizophrenia in adults. In consideration for such assignment, Indivior made an upfront non-refundable payment to the Company of $12.5 million. Indivior also agreed to make an additional $5.0 million payment to the Company contingent upon NDA approval of PERSERIS, 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 PERSERIS. The assigned patent rights include granted patents extending through at least 2026. The Company 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 Indivior 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 did not have any continuing obligations under the purchase agreement. On July 27, 2018, Indivior announced that the FDA had approved the NDA for PERSERIS thereby triggering the $5.0 million payment to the Company; this payment was received by the Company in August 2018. The Company recognized the $5.0 million as milestone revenue during the twelve months ended December 31, 2018 as there is no further performance obligation associated with this milestone payment. Amounts recognized to date related to earn-out revenues from PERSERIS have been immaterial. 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 September 30, 2019). 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. In January 2018, the Company was notified by Santen that due to a shift in near term priorities, Santen elected to reallocate research and development resources and put the Company’s program on pause until further notice. While the main program is on pause, the parties are working together on a limited set of research and development activities funded by Santen. As of September 30, 2019, the cumulative aggregate payments received by the Company under this agreement were $3.3 million. Agreement with Sandoz AG In May 2017, the Company and Sandoz AG (“Sandoz”) entered into a license agreement to develop and market POSIMIR (bupivacaine extended release solution) 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. On January 2, 2019, the Company received written notice from Sandoz that Sandoz terminated this agreement effective January 27, 2019. As a result of this termination, Sandoz returned its exclusive commercialization rights to develop and market POSIMIR in the United States. The parties are in dispute with regard to Sandoz’s obligation to pay a termination fee to the Company. The Company has initiated a formal dispute resolution process related to the termination fee. The cumulative aggregate payments received by the Company from Sandoz as of September 30, 2019 were $20.0 million under this agreement.

Financial Instruments

Financial Instruments	9 Months Ended
	Sep. 30, 2019
Fair Value Disclosures [Abstract]
Financial Instruments	Note 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. 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 September 30, 2019 is less than twelve months and these investments are rated by S&P and Moody’s at AAA or AA- for securities and A1, A2, P1 or P2 for commercial paper. The following is a summary of available-for-sale securities as of September 30, 2019 and December 31, 2018 (in thousands): September 30, 2019 Amortized Cost Unrealized Gain Unrealized Loss Estimated Fair Value Money market funds $ 543 $ — $ — $ 543 Certificates of deposit 150 — — 150 Commercial paper 44,528 1 (4 ) 44,525 U.S. Government agencies 5,000 — (1 ) 4,999 Corporate debt 5,182 6 5,188 $ 55,403 $ 7 $ (5 ) $ 55,405 Reported as: Cash and cash equivalents $ 38,024 $ — $ (4 ) $ 38,020 Short-term investments 17,229 7 (1 ) 17,235 Long-term restricted investments 150 — — 150 $ 55,403 $ 7 $ (5 ) $ 55,405 December 31, 2018 Amortized Cost Unrealized Gain Unrealized Loss Estimated Fair Value Money market funds $ 502 $ — $ — $ 502 Certificates of deposit 150 — — 150 Commercial paper 32,224 — — 32,224 $ 32,876 $ — $ — $ 32,876 Reported as: Cash and cash equivalents $ 30,055 $ — $ — $ 30,055 Short-term investments 2,671 — — 2,671 Long-term restricted investments 150 — — 150 $ 32,876 $ — $ — $ 32,876 The following is a summary of the cost and estimated fair value of available-for-sale securities at September 30, 2019, by contractual maturity (in thousands): September 30, 2019 Amortized Cost Estimated Fair Value Mature in one year or less $ 54,860 $ 54,862 $ 54,860 $ 54,862 There were no securities that have had an unrealized loss for more than 12 months as of September 30, 2019. As of September 30, 2019, 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.

Stock-Based Compensation

Stock-Based Compensation	9 Months Ended
	Sep. 30, 2019
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock-Based Compensation	Note 4. Stock-Based Compensation As of September 30, 2019, the Company has three stock-based compensation plans. The stock-based compensation cost that has been included in the statements of comprehensive loss is shown as below (in thousands): Three months ended September 30, Nine months ended September 30, 2019 2018 2019 2018 Cost of product revenues $ 21 $ 24 $ 64 $ 72 Research and development 197 238 543 929 Selling, general and administrative 632 277 1,102 838 Total stock-based compensation $ 850 $ 539 $ 1,709 $ 1,839 As of September 30, 2019 and 2018, $11,000 and $14,000 of stock-based compensation cost was capitalized in inventory on the Company’s balance sheets, respectively. The Company uses the Black-Scholes option pricing model to value its stock options. The expected life computation is based on historical exercise patterns and post-vesting termination behavior. The Company considered its historical volatility in developing its estimate of expected volatility. The Company used the following assumptions to estimate the fair value of stock options granted and shares purchased under its employee stock purchase plan for the three and nine months ended September 30, 2019 and 2018: Three months ended September 30, Nine months ended September 30, 2019 2018 2019 2018 Stock Options Risk-free rate 1.5-2.0% 2.8-3.1% 1.5-2.7% 2.7-3.1% Expected dividend yield — — — — Expected life of option (in years) 7.5-10.0 9.0-10.0 7.5-10.0 7.0-10.0 Volatility 80-83% 79-85% 79-83% 79-86% Three months ended September 30, Nine months ended September 30, 2019 2018 2019 2018 Employee Stock Purchase Plan Risk-free rate 2.4% 2.1% 2.4-2.5% 1.3-2.1% Expected dividend yield — — — — Expected life of option (in years) 0.5 0.5 0.5 0.5 Volatility 78% 66% 60-78% 66-146%

Term Loan

Term Loan	9 Months Ended
	Sep. 30, 2019
Debt Disclosure [Abstract]
Term Loan	Note 5. Term Loan In July 2016, the Company entered into a $20.0 million secured single-draw term loan with Oxford Finance LLC (Oxford Finance). The Company and Oxford Finance entered into two subsequent amendments to the Loan Agreement in February and November of 2018, for which the Company paid Oxford Finance loan modification fees of $100,000 and $900,000 respectively. As amended, the 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 June 1, 2020 and continuing through the maturity date of the term loan of November 1, 2022. The Loan Agreement provides for a floating interest rate (7.95% initially and 9.33% as of September 30, 2019) based on an index rate plus a spread. In addition, a payment equal to 10% of the principal amount of the term loan 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 of between 0.75% and 2.5% of the principal amount of the term loan depending on the timing of prepayment. The $150,000 facility fee that was paid at the original closing, the loan modification fees and other debt offering/issuance costs have been recorded as debt discount on the Company’s balance sheet and together with the final $2.0 million payment are being amortized to interest expense using the effective interest method over the revised term of the loan. 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 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 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 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 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 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. The fair value of the term loan approximates the carrying value. Future maturities and interest payments due under the term loan as of September 30, 2019, are as follows (in thousands): Three months ended December 31, 2019 $ 406 2020 6,824 2021 8,885 2022 8,912 Total minimum payments 25,027 Less amount representing interest (3,397 ) Gross balance of term loan 21,630 Less unamortized debt discount (679 ) Carrying value of term loan, net 20,951 Less term loan, current portion, net (2,981 ) Term loan, non-current portion, net $ 17,970 As of September 30, 2019, the Company was in compliance with all material covenants under the Loan Agreement and there had been no material adverse change.

Commitments

Commitments	9 Months Ended
	Sep. 30, 2019
Commitments And Contingencies Disclosure [Abstract]
Commitments	Note 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 30,149 sq. ft. Office, Laboratory and Manufacturing Lease expires 2024 (with an option to renew for an additional five years) Cupertino, CA 20,100 sq. ft. Office and Laboratory Lease expires 2024 (with an option to renew for an additional five years) Vacaville, CA 24,634 sq. ft. Manufacturing Lease expires 2023 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 $564,000 and $1.7 million for the three and nine months ended September 30, 2019, respectively, compared to $475,000 and $1.4 million for the corresponding periods in 2018. Future minimum payments under these noncancelable leases are as follows (in thousands): Operating Leases Nine months ended December 31, 2019 $ 538 2020 2,200 2021 2,126 2022 1,991 Thereafter 2,245 $ 9,100

Stockholders' Equity

Stockholders' Equity	9 Months Ended
	Sep. 30, 2019
Equity [Abstract]
Stockholders' Equity	Note 7. Stockholders’ Equity In August 2018, the Company filed a new shelf registration statement on Form S-3 with the SEC, which upon being declared effective in October 2018, terminated the November 2015 registration statement and allowed the Company to offer up to $175.0 million of securities from time to time in one or more public offerings, inclusive of up to $75.0 million of additional shares of common stock which the Company may sell, subject to certain limitations, under the 2015 Sales Agreement through Cantor Fitzgerald, acting as agent. During the three months ended September 30, 2019, the Company did not raise any net proceeds through its Controlled Equity Offering sales agreement with Cantor Fitzgerald. During the nine months ended September 30, 2019, the Company raised net proceeds (net of commissions) of approximately $538,900 from the sale of 814,450 shares of the Company’s common stock in the open market at a weighted average price of $0.68 per share, through its Controlled Equity Offering sales agreement with Cantor Fitzgerald. During the nine months ended September 30, 2018, the Company raised net proceeds (net of commissions) of approximately $16.8 million from the sale of 9,629,426 shares of the Company’s common stock in the open market at a weighted average price of $1.80 per share, through its Controlled Equity Offering sales agreement with Cantor Fitzgerald. On June 20, 2019, the Company entered into a privately negotiated transaction to sell 29,000,000 shares of our common stock to certain investors in a registered offering at a price of $0.52 per share, raising total gross proceeds to DURECT of approximately $15.1 million. This transaction closed on June 24, 2019. Total stock issuance costs related to this financing were approximately $124,000.

Subsequent Events

Subsequent Events	9 Months Ended
	Sep. 30, 2019
Subsequent Events [Abstract]
Subsequent Events	Note 8. Subsequent Event In October 2019, the Company received $10 million from Gilead that was earned via achievement of a development milestone in September 2019.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2019
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 the Company’s 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) proprietary pharmaceutical 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	Basis of Presentation These financial statements have been prepared in accordance with the rules and regulations of the Securities and Exchange Commission (SEC), and therefore do not include all the information and footnotes necessary for a complete presentation of the Company’s results of operations, financial position and cash flows in conformity with U.S. generally accepted accounting principles (U.S. GAAP). The unaudited financial statements reflect all adjustments (consisting only of normal recurring adjustments) which are, in the opinion of management, necessary for a fair presentation of the financial position at September 30, 2019, the operating results and comprehensive loss for the three and nine months ended September 30, 2019 and 2018, stockholders’ equity for the three and nine months ended September 30, 2019 and 2018, and cash flows for the nine months ended September 30, 2019 and 2018. The balance sheet as of December 31, 2018 has been derived from audited financial statements at that date but does not include all of the information and footnotes required by U.S. GAAP for complete financial statements. These financial statements and notes should be read in conjunction with the Company’s audited financial statements and notes thereto, included in the Company’s annual report on Form 10-K for the fiscal year ended December 31, 2018 filed with the SEC. The results of operations for the interim periods presented are not necessarily indicative of results that may be expected for any other interim period or for the full fiscal year.
Liquidity and Need to Raise Additional Capital	Liquidity and Need to Raise Additional Capital As of September 30, 2019, the Company had an accumulated deficit of $485.0 million as well as negative cash flows from operating activities for the nine months ended September 30, 2019. 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.
Inventories	Inventories Inventories are stated at the lower of cost or net realizable value, with cost determined on a first-in, first-out basis. The Company may be required to expense previously capitalized inventory costs upon a change in management’s judgment due to, among other potential factors, a denial or delay of approval of a customer’s product by the necessary regulatory bodies, or new information that suggests that the inventory will not be saleable. 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 consist of the following (in thousands): September 30, 2019 December 31, 2018 (unaudited) Raw materials $ 276 $ 223 Work in process 1,362 1,486 Finished goods 1,980 1,712 Total inventories $ 3,618 $ 3,421
Leases	Leases Effective January 1, 2019, the Company adopted Topic 842 using the modified retrospective transition method approach with a cumulative-effect adjustment as of January 1, 2019 in accordance with ASU No. 2018-11, Leases (Topic 842) - Targeted Improvements. Results for the nine months ended September 30, 2019 are presented under Topic 842. Other prior period amounts are not adjusted and continue to be reported in accordance with our historic accounting under previous lease guidance, ASC Topic 840: Leases (Topic 840). The Company elected the package of practical expedients permitted under the transition guidance within the new standard, which among other things, allowed the Company to carry forward the historical lease classification of those leases in place as of January 1, 2019. The adjustments due to the adoption of Topic 842 primarily related to the recognition of an operating lease right-of-use asset and operating lease liability for our leased properties. The impact of the adoption of Topic 842 on the accompanying Condensed Balance Sheet as of January 1, 2019 was as follows (in thousands): As of January 1, 2019 December 31, 2018 Adjustments Due to the Adoption of Topic 842 January 1, 2019 Condensed Balance Sheets Operating lease right-of-use assets $ — $ 7,329 $ 7,329 Operating lease liabilities: Accrued liabilities (1) $ (92 ) $ 92 $ — Other long-term liabilities (1) (270 ) 270 — Lease liabilities, current portion — (1,972 ) (1,972 ) Lease liabilities, non-current portion — (5,719 ) (5,719 ) $ (362 ) $ (7,329 ) $ (7,691 ) (1) Includes deferred rent, current and long-term portions of operating lease liabilities which were recorded against the operating lease right-of-use asset upon adoption of Topic 842 There was no effect from the adoption of Topic 842 on the Company’s condensed statement of cash flows.
Revenue Recognition	Revenue Recognition The Company enters into license and collaboration agreements under which the Company may receive upfront license fees, research funding and contingent milestone payments and royalties. Effective January 1, 2018, the Company adopted FASB ASC Topic 606, Revenue from Contracts with Customers, or ASC 606. In accordance with ASC 606, the Company changed certain characteristics of its revenue recognition accounting policy as described below. ASC 606 was applied using the modified retrospective method, where the cumulative effect of the initial application was recognized as an adjustment to opening retained earnings at January 1, 2018. The Company recorded a net increase to opening retained earnings of $470,000 with an offset entry to a contra liability account as of January 1, 2018 due to the cumulative impact of adopting Topic 606, with the impact relating to the Company’s deferred collaborative research and development revenues. There was no impact to reported total assets, revenues and operating expenses for the three and nine months ended September 30, 2019 as a result of applying Topic 606. Product Revenue, Net The Company 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. Revenues from product sales are recognized when the customer obtains control of the Company’s product, which occurs at a point in time, typically upon shipment to the customer. The Company expenses incremental costs of obtaining a contract as and when incurred if the expected amortization period of the asset that the Company would have recognized is one year or less. Trade Discounts and Allowances: The Company provides certain customers with discounts that are explicitly stated in the Company’s contracts and are recorded as a reduction of revenue in the period the related product revenue is recognized. Product Returns: Consistent with industry practice, the Company generally offers customers a limited right of return for products that have been purchased from the Company. The Company estimates the amount of its product sales that may be returned by its customers and records this estimate as a reduction of revenue in the period the related product revenue is recognized. The Company currently estimates product return liabilities using its historical sales information. The Company expects product returns to be minimal. Collaborative Research and Development and Other Revenue The Company enters into license agreements which are within the scope of Topic 606, under which it licenses certain rights to its product candidates to third parties. The terms of these arrangements typically include payment to the Company of one or more of the following: non-refundable, up-front license fees; reimbursement of development costs incurred by the Company under approved work plans; development, regulatory and commercial milestone payments; payments for manufacturing supply services the Company provides through its contract manufacturers; and royalties on net sales of licensed products. Each of these payments results in collaborative research and development revenues, except for revenues from royalties on net sales of licensed products, which are classified as royalty revenues. In determining the appropriate amount of revenue to be recognized as it fulfills its obligations under each of its agreements, the Company performs the following steps: (i) identification of the promised goods or services in the contract; (ii) determination of whether the promised goods or services are performance obligations including whether they are distinct in the context of the contract; (iii) measurement of the transaction price, including the constraint on variable consideration; (iv) allocation of the transaction price to the performance obligations; and (v) recognition of revenue when (or as) the Company satisfies each performance obligation. As part of the accounting for these arrangements, the Company must develop assumptions that require judgment to determine the stand-alone selling price for each performance obligation identified in the contract. The Company uses key assumptions to determine the standalone selling price, which may include forecasted revenues, development timelines, reimbursement rates for personnel costs, discount rates and probabilities of technical and regulatory success. The Company expects to recognize revenue for the variable consideration currently being constrained when it is probable that a significant revenue reversal will not occur. Licenses of intellectual property: If the license to the Company’s intellectual property is determined to be distinct from the other performance obligations identified in the arrangement, the Company recognizes revenues from non-refundable, up-front fees allocated to the license when the license is transferred to the customer and the customer is able to use and benefit from the license. For licenses that are bundled with other promises, the Company utilizes judgment to assess the nature of the combined performance obligation to determine whether the combined performance obligation is satisfied over time or at a point in time and, if over time, the appropriate method of measuring progress for purposes of recognizing revenue from non-refundable, up-front fees. The Company evaluates the measure of progress each reporting period and, if necessary, adjusts the measure of performance and related revenue recognition. Milestone Payments: At the inception of each arrangement that includes development milestone payments, the Company evaluates whether the milestones are considered probable of being reached and estimates the amount to be included in the transaction price using the most likely amount method. If it is probable that a significant revenue reversal would not occur, the associated milestone value is included in the transaction price. Milestone payments that are not within the control of the Company or the licensee, such as regulatory approvals, are not considered probable of being achieved until those approvals are received. The transaction price is then allocated to each performance obligation on a relative stand-alone selling price basis, for which the Company recognizes revenue as or when the performance obligations under the contract are satisfied. At the end of each subsequent reporting period, the Company re-evaluates the probability of achievement of such development milestones and any related constraint, and if necessary, adjusts its estimate of the overall transaction price. Any such adjustments are recorded on a cumulative catch-up basis, which would affect collaborative research and development revenues and net income (loss) in the period of adjustment. Manufacturing Supply Services: Arrangements that include a promise for future supply of drug product for either clinical development or commercial supply at the customer’s discretion are generally considered as options. The Company assesses if these options provide a material right to the customer and if so, they are accounted for as separate performance obligations. If the Company is entitled to additional payments when the customer exercises these options, any additional payments are recorded in collaborative research and development revenue when the customer obtains control of the goods, which is upon delivery. Royalties and Earn-outs: For arrangements that include sales-based royalties or earn-outs, including milestone payments based on the level of sales, and the license is deemed to be the predominant item to which the royalties relate, the Company recognizes revenue at the later of (i) when the related sales occur, or (ii) when the performance obligation to which some or all of the royalty has been allocated has been satisfied (or partially satisfied). To date, the Company has not recognized any material royalty revenue resulting from the Company’s collaborative arrangements or material earn-out revenue from the Company’s patent purchase agreement with Indivior. The Company receives payments from its customers based on development cost schedules established in each contract. Up-front payments are recorded as deferred revenue upon receipt or when due, and may require deferral of revenue recognition to a future period until the Company performs its obligations under these arrangements. Amounts are recorded as accounts receivable when the Company’s right to consideration is unconditional. The Company does not assess whether a contract has a significant financing component if the expectation at contract inception is such that the period between payment by the customer and the transfer of the promised goods or services to the customer will be one year or less. Total revenue by geographic region for the three and nine months ended September 30, 2019 and 2018 are as follows (in thousands): Three months ended September 30, Nine months ended September 30, 2019 2018 2019 2018 United States $ 8,977 $ 1,931 $ 14,331 $ 6,129 Europe 721 5,585 2,104 7,088 Japan 425 149 1,161 722 Other 640 371 1,283 998 Total $ 10,763 $ 8,036 $ 18,879 $ 14,937
Comprehensive Loss	Comprehensive Loss Components of other comprehensive 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.
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): Nine months ended September 30, 2019 2018 Numerators: Net loss $ (16,347 ) $ (18,023 ) Denominator: Weighted average shares used to compute basic net loss per share 172,939 159,091 Dilutive common shares from stock options and ESPP — — Weighted average shares used to compute diluted net loss per share 172,939 159,091 Net loss per share: Basic $ (0.09 ) $ (0.11 ) Diluted $ (0.09 ) $ (0.11 ) Options to purchase approximately 12.2 million and 26.2 million shares of common stock were excluded from the denominator in the calculation of diluted net loss per share for the three and nine months ended September 30, 2019, respectively, as the effect would be anti-dilutive. Options to purchase approximately 17.2 million and 15.6 million shares of common stock were excluded from the denominator in the calculation of diluted net loss per share for the three and nine months ended September 30, 2018, respectively, as the effect would be anti-dilutive.
Recently Adopted Accounting Standards	Recently Adopted Accounting Standards In February 2016, the FASB issued ASU 2016-02, Leases (Topic 842) In June 2018, the FASB issued Accounting Standards Update (“ASU”) No. 2018-07, Compensation – Stock Compensation (Topic 718) In February 2018, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2018-02, “Income Statement – Reporting Comprehensive Income (Topic 220): Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income.” Recently Issued Accounting Standards In November 2018, the Financial Accounting Standards Board (the FASB) issued ASU No. 2018-18, Collaborative Arrangements (Topic 808): Clarifying the Interaction between Topic 808 and Topic 606 (ASU 2018-18) In August 2018, the FASB issued Accounting Standards Update (“ASU”) 2018-13 , Fair Value Measurement (Topic 820): Disclosure Framework – Changes to the Disclosure Requirements for Fair Value Measurement which eliminates certain disclosure requirements for fair value measurements for all entities, requires public entities to disclose certain new information and modifies some disclosure requirements. fiscal years In January 2017, the FASB issued ASU No. 2017-04, Intangibles—Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment, (ASU 2017-04) In June 2016, the FASB issued Accounting Standards Update No. 2016-13 (ASU 2016-13) “Financial Instruments - Credit Losses: Measurement of Credit Losses on Financial Instruments.” ASU 2016-13 requires measurement and recognition of expected credit losses for financial assets. This standard is effective for fiscal years beginning after December 15, 2019, including interim reporting periods within those years and must be adopted using a modified retrospective approach, with certain exceptions. Early adoption is permitted. The Company does not expect the adoption of this standard to have a material effect on its financial statements.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	9 Months Ended
	Sep. 30, 2019
Accounting Policies [Abstract]
Summary of Components of Inventories	The Company’s inventories consist of the following (in thousands): September 30, 2019 December 31, 2018 (unaudited) Raw materials $ 276 $ 223 Work in process 1,362 1,486 Finished goods 1,980 1,712 Total inventories $ 3,618 $ 3,421
Summary of Impact of Adoption Topic 842 on Accompanying Condensed Balance Sheet	The impact of the adoption of Topic 842 on the accompanying Condensed Balance Sheet as of January 1, 2019 was as follows (in thousands): As of January 1, 2019 December 31, 2018 Adjustments Due to the Adoption of Topic 842 January 1, 2019 Condensed Balance Sheets Operating lease right-of-use assets $ — $ 7,329 $ 7,329 Operating lease liabilities: Accrued liabilities (1) $ (92 ) $ 92 $ — Other long-term liabilities (1) (270 ) 270 — Lease liabilities, current portion — (1,972 ) (1,972 ) Lease liabilities, non-current portion — (5,719 ) (5,719 ) $ (362 ) $ (7,329 ) $ (7,691 )
Summary of Total Revenue by Geographic Region	Total revenue by geographic region for the three and nine months ended September 30, 2019 and 2018 are as follows (in thousands): Three months ended September 30, Nine months ended September 30, 2019 2018 2019 2018 United States $ 8,977 $ 1,931 $ 14,331 $ 6,129 Europe 721 5,585 2,104 7,088 Japan 425 149 1,161 722 Other 640 371 1,283 998 Total $ 10,763 $ 8,036 $ 18,879 $ 14,937
Summary of Numerators and Denominators in Calculation of Basic and Diluted Net 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): Nine months ended September 30, 2019 2018 Numerators: Net loss $ (16,347 ) $ (18,023 ) Denominator: Weighted average shares used to compute basic net loss per share 172,939 159,091 Dilutive common shares from stock options and ESPP — — Weighted average shares used to compute diluted net loss per share 172,939 159,091 Net loss per share: Basic $ (0.09 ) $ (0.11 ) Diluted $ (0.09 ) $ (0.11 )

Strategic Agreements (Tables)

Strategic Agreements (Tables)	9 Months Ended
	Sep. 30, 2019
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Summary of Collaborative Research and Development and Other Revenues Associated with Company's Collaborators or Counterparties	The collaborative research and development and other revenues associated with the Company’s collaborators or counterparties are as follows (in thousands): Three months ended September 30, Nine months ended September 30, 2019 2018 2019 2018 Collaborator/Counterparty Gilead (1) $ 7,416 $ 585 $ 10,120 $ 1,892 Others (2) 325 5,106 760 5,540 Total collaborative research and development and other revenue $ 7,741 $ 5,691 $ 10,880 $ 7,432 (1) Non-feasibility related amounts were from the partial recognition of the upfront license fee and milestone payment which was $6.2 million for each of the three and nine months ended September 30, 2019, compared to zero for the corresponding periods in 2018. The Company signed a license agreement with Gilead on July 19, 2019. (2) Includes: (a) amounts related to earn-out revenue from Indivior UK Limited (Indivior) with respect to PERSERIS net sales as well as a $5.0 million milestone payment earned in from Indivior in 2018; (b) other feasibility program(s); and (c) research and development activities funded by Santen pharmaceutical Co. Ltd. (Santen). Note that in January 2018, we were notified by Santen that due to a shift in near term priorities, Santen has elected to reallocate research and development resources and put our program on pause until further notice. While the main program is on pause, the parties are working together on a limited set of research and development activities funded by Santen.
Summary of Changes in the Company's Contract Asset and Liabilities	The following table presents changes in the Company’s contract assets and liabilities for the nine months ended September 30, 2019 (in thousands): Balance at July 1, 2019 Additions Deletions Balance at September 30, 2019 Condensed Balance Sheets Assets Accounts receivable $ — $ 35,901 $ (25,231 ) $ 10,670 Total contract asset $ — $ 35,901 $ (25,231 ) $ 10,670 Liabilities Deferred revenue, current portion $ — $ 33,779 $ (6,198 ) $ 27,581 Deferred revenue, non-current portion $ — $ 1,221 $ — $ 1,221 Total contract liabilities $ — $ 35,000 $ (6,198 ) $ 28,802

Financial Instruments (Tables)

Financial Instruments (Tables)	9 Months Ended
	Sep. 30, 2019
Fair Value Disclosures [Abstract]
Summary of Money Market Funds and Available-for-Sale Securities	The following is a summary of available-for-sale securities as of September 30, 2019 and December 31, 2018 (in thousands): September 30, 2019 Amortized Cost Unrealized Gain Unrealized Loss Estimated Fair Value Money market funds $ 543 $ — $ — $ 543 Certificates of deposit 150 — — 150 Commercial paper 44,528 1 (4 ) 44,525 U.S. Government agencies 5,000 — (1 ) 4,999 Corporate debt 5,182 6 5,188 $ 55,403 $ 7 $ (5 ) $ 55,405 Reported as: Cash and cash equivalents $ 38,024 $ — $ (4 ) $ 38,020 Short-term investments 17,229 7 (1 ) 17,235 Long-term restricted investments 150 — — 150 $ 55,403 $ 7 $ (5 ) $ 55,405 December 31, 2018 Amortized Cost Unrealized Gain Unrealized Loss Estimated Fair Value Money market funds $ 502 $ — $ — $ 502 Certificates of deposit 150 — — 150 Commercial paper 32,224 — — 32,224 $ 32,876 $ — $ — $ 32,876 Reported as: Cash and cash equivalents $ 30,055 $ — $ — $ 30,055 Short-term investments 2,671 — — 2,671 Long-term restricted investments 150 — — 150 $ 32,876 $ — $ — $ 32,876
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 September 30, 2019, by contractual maturity (in thousands): September 30, 2019 Amortized Cost Estimated Fair Value Mature in one year or less $ 54,860 $ 54,862 $ 54,860 $ 54,862

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	9 Months Ended
	Sep. 30, 2019
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Summary of Stock-Based Compensation Cost that has been Included in Statements of Comprehensive Loss	The stock-based compensation cost that has been included in the statements of comprehensive loss is shown as below (in thousands): Three months ended September 30, Nine months ended September 30, 2019 2018 2019 2018 Cost of product revenues $ 21 $ 24 $ 64 $ 72 Research and development 197 238 543 929 Selling, general and administrative 632 277 1,102 838 Total stock-based compensation $ 850 $ 539 $ 1,709 $ 1,839
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 stock options granted and shares purchased under its employee stock purchase plan for the three and nine months ended September 30, 2019 and 2018: Three months ended September 30, Nine months ended September 30, 2019 2018 2019 2018 Stock Options Risk-free rate 1.5-2.0% 2.8-3.1% 1.5-2.7% 2.7-3.1% Expected dividend yield — — — — Expected life of option (in years) 7.5-10.0 9.0-10.0 7.5-10.0 7.0-10.0 Volatility 80-83% 79-85% 79-83% 79-86% Three months ended September 30, Nine months ended September 30, 2019 2018 2019 2018 Employee Stock Purchase Plan Risk-free rate 2.4% 2.1% 2.4-2.5% 1.3-2.1% Expected dividend yield — — — — Expected life of option (in years) 0.5 0.5 0.5 0.5 Volatility 78% 66% 60-78% 66-146%

Term Loan (Tables)

Term Loan (Tables)	9 Months Ended
	Sep. 30, 2019
Debt Disclosure [Abstract]
Schedule of Future Maturities and Interest Payments due under Term Loan	The fair value of the term loan approximates the carrying value. Future maturities and interest payments due under the term loan as of September 30, 2019, are as follows (in thousands): Three months ended December 31, 2019 $ 406 2020 6,824 2021 8,885 2022 8,912 Total minimum payments 25,027 Less amount representing interest (3,397 ) Gross balance of term loan 21,630 Less unamortized debt discount (679 ) Carrying value of term loan, net 20,951 Less term loan, current portion, net (2,981 ) Term loan, non-current portion, net $ 17,970

Commitments (Tables)

Commitments (Tables)	9 Months Ended
	Sep. 30, 2019
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 30,149 sq. ft. Office, Laboratory and Manufacturing Lease expires 2024 (with an option to renew for an additional five years) Cupertino, CA 20,100 sq. ft. Office and Laboratory Lease expires 2024 (with an option to renew for an additional five years) Vacaville, CA 24,634 sq. ft. Manufacturing Lease expires 2023 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): Operating Leases Nine months ended December 31, 2019 $ 538 2020 2,200 2021 2,126 2022 1,991 Thereafter 2,245 $ 9,100

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($) shares in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Jan. 01, 2019	Dec. 31, 2018	Jan. 01, 2018
Summary Of Significant Accounting Policies [Line Items]
Date of incorporation			Feb. 6, 1998
Accumulated deficit	$ 484,971,000		$ 484,971,000			$ 468,624,000
Options to purchase common stock excluded from computation of diluted net loss per share	12.2	17.2	26.2	15.6
Recognize additional lease liabilities					$ 7,700,000	$ 362,000
Right-of-use assets	$ 6,397,000		$ 6,397,000		$ 7,300,000
Minimum [Member]
Summary Of Significant Accounting Policies [Line Items]
Operating lease assets and liabilities recognition period			12 months
Accounting Standards Update 2014-09 [Member]
Summary Of Significant Accounting Policies [Line Items]
Increase in retained earnings due to cumulative impact of adopting Topic 606							$ 470,000

Summary of Significant Accoun_5

Summary of Significant Accounting Policies - Summary of Components of Inventories (Detail) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Inventory Net [Abstract]
Raw materials	$ 276	$ 223
Work in process	1,362	1,486
Finished goods	1,980	1,712
Total inventories	$ 3,618	$ 3,421

Summary of Significant Accoun_6

Summary of Significant Accounting Policies - Summary of Impact of Adoption Topic 842 on Accompanying Condensed Balance Sheet (Detail) - USD ($) $ in Thousands		Sep. 30, 2019	Jan. 01, 2019	Dec. 31, 2018
Operating lease right-of-use assets		$ 6,397	$ 7,300
Lease liabilities, current portion		(2,028)
Lease liabilities, non-current portion		$ (4,836)
Operating lease, liability			(7,700)	$ (362)
Accrued liabilities [Member]
Lease liabilities, current portion	[1]			(92)
Other long-term liabilities [Member]
Lease liabilities, non-current portion	[1]			$ (270)
Accounting Standards Update 2016-02 [Member]
Operating lease right-of-use assets			7,329
Lease liabilities, current portion			(1,972)
Lease liabilities, non-current portion			(5,719)
Operating lease, liability			(7,691)
Accounting Standards Update 2016-02 [Member] | Adjustments Due to the Adoption of Topic 842 [Member]
Operating lease right-of-use assets			7,329
Lease liabilities, current portion			(1,972)
Lease liabilities, non-current portion			(5,719)
Operating lease, liability			(7,329)
Accounting Standards Update 2016-02 [Member] | Accrued liabilities [Member] | Adjustments Due to the Adoption of Topic 842 [Member]
Lease liabilities, current portion	[1]		92
Accounting Standards Update 2016-02 [Member] | Other long-term liabilities [Member] | Adjustments Due to the Adoption of Topic 842 [Member]
Lease liabilities, non-current portion	[1]		$ 270
[1]	Includes deferred rent, current and long-term portions of operating lease liabilities which were recorded against the operating lease right-of-use asset upon adoption of Topic 842

Summary of Significant Accoun_7

Summary of Significant Accounting Policies - Summary of Total Revenue by Geographic Region (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	$ 10,763	$ 8,036	$ 18,879	$ 14,937
United States [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	8,977	1,931	14,331	6,129
Europe [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	721	5,585	2,104	7,088
Japan [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	425	149	1,161	722
Other [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	$ 640	$ 371	$ 1,283	$ 998

Summary of Significant Accoun_8

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						9 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Sep. 30, 2019	Sep. 30, 2018
Numerators:
Net loss	$ (1,990)	$ (7,227)	$ (7,130)	$ (2,715)	$ (7,011)	$ (8,297)	$ (16,347)	$ (18,023)
Denominator:
Weighted average shares used to compute basic net loss per share	192,039			162,002			172,939	159,091
Dilutive common shares from stock options and ESPP							0	0
Weighted average shares used to compute diluted net loss per share	192,039			162,002			172,939	159,091
Net loss per share:
Basic	$ (0.01)			$ (0.02)			$ (0.09)	$ (0.11)
Diluted	$ (0.01)			$ (0.02)			$ (0.09)	$ (0.11)

Strategic Agreements - Summary

Strategic Agreements - Summary of Collaborative Research and Development and Other Revenues Associated with Company's Collaborators or Counterparties (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Revenue	$ 10,763	$ 8,036	$ 18,879	$ 14,937
Collaborative Research and Development and Other Revenue [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Revenue	7,741	5,691	10,880	7,432
Agreement with Gilead Sciences, Inc [Member] | Collaborative Research and Development and Other Revenue [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Revenue	7,416	585	10,120	1,892
Agreements With Other Collaborators or Counterparties [Member] | Collaborative Research and Development and Other Revenue [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Revenue	$ 325	$ 5,106	$ 760	$ 5,540

Strategic Agreements - Summar_2

Strategic Agreements - Summary of Collaborative Research and Development and Other Revenues Associated with Company's Collaborators or Counterparties (Parenthetical) (Detail) - USD ($)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Total revenues	$ 10,763,000	$ 8,036,000	$ 18,879,000	$ 14,937,000
Agreement with Gilead Sciences, Inc [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Amount related to the milestone payment earned	6,200,000	0	6,200,000	0
Agreement with Gilead Sciences, Inc [Member] | License Fees [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Total revenues	$ 6,200,000	$ 0	$ 6,200,000	$ 0
Patent Purchase Agreement with Indivior [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Amount related to the milestone payment earned					$ 5,000,000

Strategic Agreements - Agreemen

Strategic Agreements - Agreement with Gilead Sciences, Inc - Additional Information (Detail) - USD ($)	Jul. 19, 2019	Oct. 31, 2019	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Total revenues			$ 10,763,000	$ 8,036,000	$ 18,879,000	$ 14,937,000
Agreement with Gilead [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Total revenues	$ 25,000,000
Performance milestone payments based on successful development			10,000,000		10,000,000
Upfront non-refundable payment received			25,000,000		25,000,000
Deferred revenue recognized			6,200,000		6,200,000
Deferred revenue			28,800,000		28,800,000
Agreement with Gilead [Member] | Subsequent Event [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Performance milestone payments based on successful development		$ 10,000,000
Amount related to the milestone payment earned		$ 10,000,000
Agreement with Gilead [Member] | Maximum [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Performance milestone payments based on successful development	75,000,000
Agreement with Gilead [Member] | Sales-Based Milestones [Member] | Maximum [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Performance milestone payments based on successful development	70,000,000
Agreement with Gilead [Member] | Upfront, Development, Regulatory and Sales-Based Milestones [Member] | Maximum [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Performance milestone payments based on successful development	$ 150,000,000
Agreement with Gilead [Member] | Collaborative Research and Development and Other Revenue [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Deferred revenue recognized			$ 1,200,000		$ 3,900,000

Strategic Agreements - Agreem_2

Strategic Agreements - Agreement with Gilead Sciences, Inc - Additional Information (Details)	Sep. 30, 2019
Agreement with Gilead [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2019-09-30
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Estimated period for performance obligation	1 year 3 months

Strategic Agreements - Changes

Strategic Agreements - Changes in Company's of Contract Assets and Liabilities (Detail) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Liabilities
Deferred revenue, current portion	$ 27,582
Deferred revenue, non-current portion	2,033	$ 812
Agreement with Gilead [Member]
Assets
Accounts receivable	10,670
Liabilities
Deferred revenue, current portion	27,581
Deferred revenue, non-current portion	1,221
Total contract liabilities	28,802
Agreement with Gilead [Member] | Additions [Member]
Assets
Accounts receivable	35,901
Liabilities
Deferred revenue, current portion	33,779
Deferred revenue, non-current portion	1,221
Total contract liabilities	35,000
Agreement with Gilead [Member] | Deletions [Member]
Assets
Accounts receivable	25,231
Liabilities
Deferred revenue, current portion	6,198
Total contract liabilities	$ 6,198

Strategic Agreements - Patent P

Strategic Agreements - Patent Purchase Agreement with Indivior - Additional Information (Detail) - USD ($) $ in Thousands	Sep. 26, 2017	Sep. 30, 2017	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018	Dec. 31, 2017	Jul. 27, 2018
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Total revenues			$ 10,763	$ 8,036	$ 18,879	$ 14,937
Patent Purchase Agreement with Indivior [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Upfront non-refundable payment received	$ 12,500
Granted patents extending year, minimum	2026
Patent Purchase Agreement with Indivior [Member] | Intellectual Property Rights [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Total revenues		$ 12,500						$ 12,500
Patent Purchase Agreement with Indivior [Member] | Regulatory Based Milestone [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Performance milestone payments based on successful development	$ 5,000								$ 5,000
Revenue recognition milestone achieved							$ 5,000

Strategic Agreements - Agreem_3

Strategic Agreements - Agreement with Santen Pharmaceutical Co., Ltd. - Additional Information (Detail) - USD ($)	Dec. 11, 2014	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Total revenues		$ 10,763,000	$ 8,036,000	$ 18,879,000	$ 14,937,000
Agreement with Santen Pharmaceutical Co., Ltd. [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Cumulative aggregate payments received by the Company				3,300,000
Agreement with Santen Pharmaceutical Co., Ltd. [Member] | License Fees [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Total revenues	$ 2,000,000
Agreement with Santen Pharmaceutical Co., Ltd. [Member] | Maximum [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Future milestone payments	76,000,000
Agreement with Santen Pharmaceutical Co., Ltd. [Member] | Development-Based Milestones [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Future milestone payments	13,000,000
Agreement with Santen Pharmaceutical Co., Ltd. [Member] | Commercialization-Based Milestones [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Future milestone payments	$ 63,000,000
Revenue recognition milestone achieved				$ 0

Strategic Agreements - Agreem_4

Strategic Agreements - Agreement with Sandoz AG - Additional Information (Detail) $ in Millions	9 Months Ended
	Sep. 30, 2019USD ($)
Agreement with Sandoz AG [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Cumulative aggregate payments received by the Company	$ 20

Financial Instruments - Summary

Financial Instruments - Summary of Money Market Funds and Available-for-Sale Securities (Detail) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 55,403	$ 32,876
Unrealized Gain	7
Unrealized Loss	(5)
Estimated Fair Value	55,405	32,876
Money market funds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	543	502
Estimated Fair Value	543	502
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	44,528	32,224
Unrealized Gain	1
Unrealized Loss	(4)
Estimated Fair Value	44,525	32,224
U.S. Government agencies [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	5,000
Unrealized Loss	(1)
Estimated Fair Value	4,999
Corporate debt [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	5,182
Unrealized Gain	6
Estimated Fair Value	5,188
Cash and cash equivalents [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	38,024	30,055
Unrealized Loss	(4)
Estimated Fair Value	38,020	30,055
Short-term investments [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	17,229	2,671
Unrealized Gain	7
Unrealized Loss	(1)
Estimated Fair Value	17,235	2,671
Long-term restricted investments [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	150	150
Estimated Fair Value	$ 150	$ 150

Financial Instruments - Summa_2

Financial Instruments - Summary of Cost and Estimated Fair Value of Available-for-Sale Securities by Contractual Maturity (Detail) $ in Thousands	Sep. 30, 2019USD ($)
Investments Debt And Equity Securities [Abstract]
Mature in one year or less, Amortized Cost	$ 54,860
Amortized Cost	54,860
Mature in one year or less, Estimated Fair Value	54,862
Estimated Fair Value	$ 54,862

Financial Instruments - Additio

Financial Instruments - Additional Information (Detail)	Sep. 30, 2019USD ($)
Investments Debt And Equity Securities [Abstract]
Unrealized loss of securities	$ 0

Stock-Based Compensation - Summ

Stock-Based Compensation - Summary of Stock-Based Compensation Cost that has been Included in Statements of Comprehensive Loss (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock-based compensation	$ 850	$ 539	$ 1,709	$ 1,839
Cost of product revenues [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock-based compensation	21	24	64	72
Research and development [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock-based compensation	197	238	543	929
Selling, general and administrative [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock-based compensation	$ 632	$ 277	$ 1,102	$ 838

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional Information (Detail) - USD ($)	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock-based compensation cost capitalized in inventory	$ 11,000	$ 14,000

Stock-Based Compensation - Su_2

Stock-Based Compensation - Summary of Assumptions Used to Estimate Fair Value of Options Granted and Shares Purchased (Detail)	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Employees Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free rate	2.40%	2.10%
Risk-free rate, minimum			2.40%	1.30%
Risk-free rate, maximum			2.50%	2.10%
Expected dividend yield	0.00%	0.00%	0.00%	0.00%
Expected life of option (in years)	6 months	6 months	6 months	6 months
Volatility	78.00%	66.00%
Volatility, minimum			60.00%	66.00%
Volatility, maximum			78.00%	146.00%
Stock Option Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free rate, minimum	1.50%	2.80%	1.50%	2.70%
Risk-free rate, maximum	2.00%	3.10%	2.70%	3.10%
Expected dividend yield	0.00%	0.00%	0.00%	0.00%
Volatility, minimum	80.00%	79.00%	79.00%	79.00%
Volatility, maximum	83.00%	85.00%	83.00%	86.00%
Stock Option Plan [Member] | Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected life of option (in years)	7 years 6 months	9 years	7 years 6 months	7 years
Stock Option Plan [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected life of option (in years)	10 years	10 years	10 years	10 years

Term Loan - Additional Informat

Term Loan - Additional Information (Detail) - Oxford Finance LLC Term Loan [Member] - USD ($)	1 Months Ended			9 Months Ended
	Nov. 30, 2018	Feb. 28, 2018	Jul. 31, 2016	Sep. 30, 2019
Debt Instrument [Line Items]
Secured term loan			$ 20,000,000
Term loan repayment description				As amended, the 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 June 1, 2020 and continuing through the maturity date of the term loan of November 1, 2022.
First principal payment date			Jun. 1, 2020
Term loan, maturity date			Nov. 1, 2022
Interest rate on term loan			7.95%	9.33%
Term loan, floating interest rate basis				index rate plus a spread
Facility fee paid at final payment			$ 150,000
Percentage of an additional payment equal to principal amount			10.00%
Debt offering/issuance costs			$ 2,000,000
Loan modification fee	$ 900,000	$ 100,000
Minimum [Member]
Debt Instrument [Line Items]
Percentage of prepayment fee			0.75%
Maximum [Member]
Debt Instrument [Line Items]
Percentage of prepayment fee			2.50%

Term Loan - Schedule of Future

Term Loan - Schedule of Future Maturities and Interest Payments due under Term Loan (Detail) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Future maturities and interest payments under the term loan:
Three months ended December 31, 2019	$ 406
2020	6,824
2021	8,885
2022	8,912
Total minimum payments	25,027
Less amount representing interest	(3,397)
Gross balance of term loan	21,630
Less unamortized debt discount	(679)
Carrying value of term loan, net	20,951
Less term loan, current portion, net	(2,981)
Term loan, non-current portion, net	$ 17,970	$ 20,533

Commitments - Summary of Lease

Commitments - Summary of Lease Arrangements of Company Facilities (Detail)	9 Months Ended
	Sep. 30, 2019ft²Option
Vacaville, CA [Member] | Manufacturing [Member]
Property Subject To Or Available For Operating Lease [Line Items]
Approximate Square Feet	24,634
Expiration	Lease expires 2023
Lease expiration year	2023
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	2021
Lease renewal term	5 years
Number of renewal option for lease | Option	2
Cupertino, CA [Member] | Office, Laboratory and Manufacturing [Member]
Property Subject To Or Available For Operating Lease [Line Items]
Lease expiration year	2024
Lease renewal term	5 years
Cupertino, CA [Member] | Office, Laboratory and Manufacturing [Member] | Lease Amendment [Member]
Property Subject To Or Available For Operating Lease [Line Items]
Approximate Square Feet	30,149
Expiration	Lease expires 2024 (with an option to renew for an additional five years)
Cupertino, CA [Member] | Office and Laboratory [Member]
Property Subject To Or Available For Operating Lease [Line Items]
Lease expiration year	2024
Lease renewal term	5 years
Cupertino, CA [Member] | Office and Laboratory [Member] | Lease Amendment [Member]
Property Subject To Or Available For Operating Lease [Line Items]
Approximate Square Feet	20,100
Expiration	Lease expires 2024 (with an option to renew for an additional five years)

Commitments - Additional Inform

Commitments - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Commitments And Contingencies Disclosure [Abstract]
Rent expenses of operating leases	$ 564,000	$ 475,000	$ 1,700	$ 1,400

Commitments - Schedule of Futur

Commitments - Schedule of Future Operating Lease Minimum Payments (Detail) $ in Thousands	Sep. 30, 2019USD ($)
Leases [Abstract]
Nine months ended December 31, 2019	$ 538
2020	2,200
2021	2,126
2022	1,991
Thereafter	2,245
Total operating leases future minimum payments	$ 9,100

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Detail) - USD ($)	Jun. 20, 2019	Sep. 30, 2019	Sep. 30, 2018	Oct. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Proceeds from sale of common stock, net of commission		$ 15,649,000	$ 18,456,000
Sale of stock number of shares issued in transaction	29,000,000
Sale of stock price per share	$ 0.52
Gross proceeds from sale of common stock	$ 15,100,000
Payments of stock issuance costs	$ 124,000
Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Securities offered				$ 175,000,000
Controlled Equity Offering Program [Member] | Cantor Fitzgerald Co [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Proceeds from sale of common stock, net of commission		$ 538,900,000	$ 16,800,000
Sale of common stock during period		814,450,000	9,629,426,000
Common stock weighted average price		$ 0.68	$ 1.80
Controlled Equity Offering Program [Member] | Cantor Fitzgerald Co [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Securities offered				$ 75,000,000

Subsequent Events - Additional

Subsequent Events - Additional Information (Detail) - Agreement with Gilead [Member] - USD ($) $ in Millions	Oct. 31, 2019	Sep. 30, 2019
Subsequent Event [Line Items]
Performance milestone payments based on successful development		$ 10
Subsequent Event [Member]
Subsequent Event [Line Items]
Performance milestone payments based on successful development	$ 10