Immune Design 10-Q 1 Aug 18 2018 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2018	Jul. 30, 2018
Document and Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2018
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	Q2
Trading Symbol	IMDZ
Entity Registrant Name	Immune Design Corp.
Entity Central Index Key	1,437,786
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Entity Common Stock, Shares Outstanding		48,164,828

CONDENSED CONSOLIDATED BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 73,430	$ 72,454
Short-term investments	46,795	68,653
Accounts receivable	660	647
Inventory	900	684
Prepaid expenses	2,111	1,571
Restricted cash	0	6,000
Other receivables	88	3,134
Total current assets	123,984	153,143
Property and equipment, net	548	491
Security deposit	200	200
Total assets	124,732	153,834
Current liabilities:
Accounts payable	3,156	2,334
Accrued liabilities	4,745	6,186
Accrued litigation-related settlement	0	6,000
Total current liabilities	7,901	14,520
Other non-current liabilities	107	102
Commitments and contingencies	0	0
Stockholders’ equity:
Common stock, $0.001 par value; 100,000,000 shares authorized at June 30, 2018 (unaudited) and December 31, 2017; 48,164,828 and 48,068,650 shares issued and outstanding at June 30, 2018 (unaudited) and December 31, 2017, respectively	48	48
Preferred stock, $0.001 par value; 10,000,000 shares authorized; no shares issued or outstanding	0	0
Additional paid-in capital	379,576	374,970
Accumulated deficit	(262,865)	(235,757)
Accumulated other comprehensive loss	(35)	(49)
Total stockholders’ equity	116,724	139,212
Total liabilities and stockholders’ equity	$ 124,732	$ 153,834

CONDENSED CONSOLIDATED BALANCE3

CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Jun. 30, 2018	Dec. 31, 2017
Common stock, $0.001 par value; 100,000,000 shares authorized at March 31, 2018 (unaudited) and December 31, 2017; 48,125,008 and 48,068,650 shares issued and outstanding at March 31, 2018 (unaudited) and December 31, 2017, respectively
Par value per share (in dollars per share)	$ 0.001	$ 0.001
Shares authorized (in shares)	100,000,000	100,000,000
Shares issued (in shares)	48,164,828	48,068,650
Shares outstanding (in shares)	48,164,828	48,068,650
Preferred stock, $0.001 par value; 10,000,000 shares authorized; no shares issued or outstanding
Par value per share (in dollars per share)	$ 0.001	$ 0.001
Shares authorized (in shares)	10,000,000	10,000,000
Shares issued (in shares)	0	0
Shares outstanding (in shares)	0	0

CONDENSED CONSOLIDATED STATEMEN

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Revenues:
Total revenues	$ 755	$ 729	$ 1,258	$ 6,194
Operating expenses:
Cost of product sales	140	18	147	55
Research and development	11,000	10,863	21,311	24,901
General and administrative	4,006	3,888	8,001	8,023
Total operating expenses	15,146	14,769	29,459	32,979
Loss from operations	(14,391)	(14,040)	(28,201)	(26,785)
Interest and other income	583	194	1,093	319
Net loss	(13,808)	(13,846)	(27,108)	(26,466)
Unrealized gain (loss) on investments	32	4	14	(19)
Comprehensive loss	$ (13,776)	$ (13,842)	$ (27,094)	$ (26,485)
Basic and diluted net loss per share (in dollars per share)	$ (0.29)	$ (0.54)	$ (0.56)	$ (1.04)
Weighted-average shares used to compute basic and diluted net loss per share (in shares)	48,125,652	25,567,482	48,124,033	25,515,630
Collaborative revenue
Revenues:
Total revenues	$ 334	$ 681	$ 830	$ 5,885
Product sales
Revenues:
Total revenues	$ 421	$ 48	$ 428	$ 309

CONDENSED CONSOLIDATED STATEME5

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Operating activities
Net loss	$ (27,108)	$ (26,466)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	186	169
Amortization of premium/discount on investments	(292)	56
Stock-based compensation expense	4,249	4,452
Changes in operating assets and liabilities:
Accounts receivable	(13)	22
Inventory	(216)	(17)
Prepaid expenses	(540)	1,223
Other receivables	3,046	3,033
Other assets	0	(325)
Accounts payable	822	(313)
Accrued liabilities	(1,441)	786
Accrued litigation-related settlement	(6,000)	0
Deferred rent and other liabilities	5	(2,461)
Net cash used in operating activities	(27,302)	(19,841)
Investing activities
Purchases of property and equipment	(243)	(261)
Maturities of short-term investments	42,000	28,000
Purchases of short-term investments	(19,836)	(11,998)
Net cash provided by investing activities	21,921	15,741
Financing activities
Proceeds from issuances of common stock under equity incentive plans	357	397
Net cash provided by financing activities	357	397
Net decrease in cash, cash equivalents and restricted cash	(5,024)	(3,703)
Cash, cash equivalents and restricted cash, beginning of period	78,654	45,214
Cash, cash equivalents and restricted cash, end of period	$ 73,630	$ 41,511

CONDENSED CONSOLIDATED STATEME6

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - RECONCILIATION OF CASH, CASH EQUIVALENTS AND RESTRICTED CASH - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017	Jun. 30, 2017	Dec. 31, 2016
Statement of Cash Flows [Abstract]
Cash and cash equivalents	$ 73,430	$ 72,454	$ 35,311
Restricted cash	0	6,000	6,000
Security deposit	200	200	200
Total cash, cash equivalents and restricted cash	$ 73,630	$ 78,654	$ 41,511	$ 45,214

Description of the Business

Description of the Business	6 Months Ended
	Jun. 30, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Description of the Business	Description of the Business Immune Design Corp. (we, us or our) is a clinical-stage immunotherapy company focused on cancer with next-generation in vivo approaches designed to enable the body’s immune system to fight disease. We have engineered our technologies to activate the immune system’s natural ability to create tumor-specific cytotoxic T cells (CTLs) to fight cancer. We are developing multiple product candidates from our two discovery platforms, ZVex ® and GLAAS ® . Our primary product candidates, CMB305 and G100, utilize different immuno-oncology approaches and are being evaluated in multiple Phase 1 and Phase 2 trials. We plan to commence a Phase 3 clinical trial of CMB305 in patients with synovial sarcoma this year. In addition, we have licensed to third parties the right to use the GLAAS platform in select infectious disease and allergy indications. We were incorporated in February 2008 in the State of Delaware. Our operations are headquartered in Seattle, Washington, and we have an additional facility in South San Francisco, California.

Summary of Significant Accounti

Summary of Significant Accounting Policies	6 Months Ended
	Jun. 30, 2018
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies Basis of Presentation and Use of Estimates The accompanying condensed consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles (GAAP). To conform with GAAP, the preparation of our financial statements requires management to make judgments, assumptions, and estimates that affect the amounts reported in our condensed consolidated financial statements and accompanying notes. Estimates are used for, but not limited to, accruals for clinical trial activity, other accrued liabilities, and assumptions used in determining stock-based compensation expenses. We base our estimates on historical experience and on various other assumptions that we believe to be reasonable. Actual results could differ materially from those estimates. Principles of Consolidation Our condensed consolidated financial statements include the financial position and results of operations of Immune Design Corp. and Immune Design Ltd., our wholly owned subsidiary. Immune Design Ltd. was incorporated in the United Kingdom in February 2016, and to date, there have been no financial transactions or balances related to this entity. Unaudited Interim Financial Information The accompanying unaudited condensed consolidated financial statements as of June 30, 2018 and for the three and six months ended June 30, 2018 and 2017 and the related interim information contained within the notes to the condensed consolidated financial statements are unaudited. The unaudited interim consolidated financial statements have been prepared on the same basis as the audited consolidated financial statements and in the opinion of management, reflect all normal recurring adjustments necessary for a fair statement of our financial position for the interim periods presented. The results of operations for the three and six months ended June 30, 2018 are not necessarily indicative of the results to be expected for the year ended December 31, 2018 or for other future interim periods or years. The accompanying unaudited condensed consolidated financial statements should be read in conjunction with the audited consolidated financial statements for the year ended December 31, 2017 included in our Annual Report on Form 10-K for the year ended December 31, 2017 , filed with the Securities and Exchange Commission (SEC) on March 14, 2018 (Annual Report). Short-Term Investments Our short-term investments include funds invested in U.S. Treasury securities with a final maturity of each security of less than one year. All investments are classified as available-for-sale securities and are recorded at fair value based on quoted prices in active markets, with unrealized gains and losses excluded from earnings and reported in other comprehensive income (loss). Purchase premiums and discounts are recognized in interest income using the interest method over the terms of the securities. Realized gains and losses and declines in fair value that are deemed to be other than temporary are reflected in the condensed consolidated statements of operations and comprehensive income (loss) using the specific-identification method. Restricted Cash Restricted cash includes funds used to secure our obligations associated with the settlement of all claims and disputes under our Settlement Agreement with TheraVectys SA (TVS). A deposit of zero and $6.0 million was held in escrow restricted from withdrawal as of June 30, 2018 and December 31, 2017 , respectively. See Note 12 for additional information. In addition, we held a security deposit under a standby letter of credit associated with our laboratory and office space lease in Seattle, Washington, to be drawn down by our landlord if the lease is breached. The security deposit is classified as a non-current asset on our Condensed Consolidated Balance Sheets. Comprehensive Loss Comprehensive loss is composed of net loss and other comprehensive income or loss that are excluded from net loss. For the periods presented, other comprehensive income consists of unrealized gains on our available-for-sale securities. Revenue Recognition Effective January 1, 2018, we adopted Accounting Standards Codification (ASC) Topic 606, Revenue from Contracts with Customers , using the modified retrospective method and there was no impact to our financial position and results of operations as a result of the adoption. This standard applies to all contracts with customers, except for contracts that are within the scope of other standards, such as leases, insurance, collaboration arrangements and financial instruments. Under Topic 606, an entity recognizes revenue when its customer obtains control of promised goods or services, in an amount that reflects the consideration which the entity expects to receive in exchange for those goods or services. To determine revenue recognition for arrangements that an entity determines are within the scope of Topic 606, the entity performs the following five steps: (i) identify the contract(s) with a customer; (ii) identify the performance obligations in the contract; (iii) determine the transaction price; (iv) allocate the transaction price to the performance obligations in the contract; and (v) recognize revenue when (or as) the entity satisfies a performance obligation. We only apply the five-step model to contracts when it is probable that the entity will collect the consideration it is entitled to in exchange for the goods or services it transfers to the customer. At contract inception, once the contract is determined to be within the scope of Topic 606, we assess the goods or services promised within each contract and determine those that are performance obligations, and assess whether each promised good or service is distinct. We then recognize as revenue the amount of the transaction price that is allocated to the respective performance obligation when (or as) the performance obligation is satisfied. We derive our revenue from collaboration and licensing agreements and the sale of products associated with material transfer, collaboration and supply agreements. License, Collaboration and Other Revenues We enter into collaboration and out-licensing agreements which are within the scope of Topic 606, under which we perform research and development activities and license certain rights to our intellectual property to third parties. The terms of these arrangements typically include payment to us of one or more of the following: non-refundable, up-front license fees; development, regulatory and commercial milestone payments; payments for manufacturing supply services we provide through our contract manufacturers; and royalties on net sales of licensed products. Each of these payments results in license, collaboration and other 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 we fulfill our obligations under each of these agreements, we perform the following steps: (1) 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) we satisfy each performance obligation. As part of the accounting for these arrangements, we must develop assumptions that require judgment to determine the stand-alone selling price for each performance obligation identified in the contract. We use key assumptions to determine the stand-alone selling price, which may include forecasted revenues, development timelines, reimbursement rates for personnel costs, discount rates and probabilities of technical and regulatory success. Licensing of intellectual property. If the license to our intellectual property is determined to be distinct from the other performance obligations identified in the arrangement, we recognize revenue 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, we utilize 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. We evaluate the measure of progress each reporting period and, if necessary, adjust the measure of performance and related revenue recognition. Milestone payments . At the inception of each arrangement that includes development milestone payments, we evaluate whether the milestones are considered probable of being reached and estimate 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 our control 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 we recognize revenue as or when the performance obligations under the contract are satisfied. At the end of each subsequent reporting period, we re-evaluate the probability of achievement of such development milestones and any related constraint, and if necessary, adjust our estimate of the overall transaction price. Any such adjustments are recorded on a cumulative catch-up basis, which would affect license, collaboration and other revenues and earnings in the period of adjustment. Manufacturing supply services. Arrangements that include a promise for future supply of drug substance or drug product for either clinical development or commercial supply at the customer’s discretion are generally considered as options. We assess if these options provide material rights to the licensee and if so, they are accounted for as separate performance obligations. If we are entitled to additional payments when the customer exercises these options, any additional payments are recorded when the customer obtains control of the goods, which is upon shipment. Royalties. Arrangements that include sales-based royalties, including milestone payments based on the level of sales, and the license is deemed to be the predominant item to which the royalties relate, we recognize 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, we have not recognized any royalty revenue resulting from any of our collaboration or out-licensing agreements. Product Sales Revenue from product sales of glucopyranosyl lipid A (GLA), a product from our GLAAS platforms, is recognized when the Customer obtains control of the Company’s product, which occurs at a point in time, typically upon shipment to the Customer. All revenues associated from the sale of GLA products supplied by us are reported under product sales with the applicable costs reported under cost of product sales. Product sales consist of the direct costs associated with the manufacture and formulation of GLA, including costs to purchase raw materials, third-party contract manufacturing costs, assay testing and ongoing product stability testing. Accrued Liabilities and Research and Development Related Accruals Accrued liabilities and research and development related accruals represent accrued compensation including vacation accruals and accrued expenses. As part of the process of preparing our consolidated financial statements, we are required to estimate our accrued professional services and research and development expenses. This process involves reviewing contracts and vendor agreements, communicating with appropriate internal personnel to identify services that have been performed on our behalf and estimating the associated cost incurred for the service when we have not yet been invoiced or otherwise notified of actual cost. We make estimates of our accrued expenses as of each balance sheet date in our consolidated financial statements based on facts and circumstances known to us and periodically confirming the accuracy of our estimates with service providers and making adjustments, if necessary. We base our expenses related to contract manufacturing and clinical studies on our estimates of the services received and efforts expended pursuant to contracts with multiple contract manufacturing organizations and clinical research organizations that conduct and manage supply and clinical studies on our behalf. The financial terms of these agreements vary from contract to contract and may result in uneven payment flows. In accruing service fees, we estimate the time period over which services will be performed and the level of effort to be expended in each period. If the actual timing of the performance of services or the level of effort varies from our estimate, we adjust the accrual accordingly. Although we do not expect our estimates to be materially different from amounts actually incurred, if our estimates of the status and timing of services performed differ from the actual status and timing of services performed, we may report amounts that are too high or too low in any particular period. Accounting estimates and judgments related to contract manufacturing activities and clinical trials are inherently uncertain. We base our estimates on the best information available at the time. As appropriate, estimates are assessed periodically and updated to reflect current information and any changes will generally be reflected in the period first identified. To date, we have not experienced any significant adjustments to our estimates. Recently Adopted Accounting Pronouncements In August 2016, the Financial Accounting Standards Board (FASB) issued ASU No. 2016-15 which provides new guidance on the classification of certain cash receipts and payments in the statement of cash flows. The new guidance is intended to reduce diversity in practice in how certain transactions are classified in the statement of cash flows. We adopted the new standard in the first quarter of 2018. Adoption of this standard did not have a material impact on our consolidated financial statements. In November 2016, the FASB issued ASU No. 2016-18 that relates to restricted cash. The new guidance requires amounts generally described as restricted cash and restricted cash equivalents should be included with cash and cash equivalents when reconciling the beginning-of-period and end-of-period total amounts shown on the statement of cash flows. We adopted the new standard in the first quarter of 2018. Adoption of this standard did not have a material impact on our consolidated financial statements. In May 2017, the FASB issued ASU No. 2017-09 to provide clarity and reduce both diversity in practice and cost and complexity when applying the guidance in Topic 718 about a change to the terms and conditions of a share-based payment award. The amendments in this update provide guidance about which changes to the terms or conditions of a share-based payment award require an entity to apply modification accounting in Topic 718. We adopted the new standard in the first quarter of 2018. Adoption of this standard did not have a material impact on our consolidated financial statements. Recent Accounting Pronouncements In February 2016, the FASB issued ASU 2016-02 related to lease accounting. This standard will require organizations that lease assets to recognize on the balance sheet the assets and liabilities for the rights and obligations created by those leases that are greater than 12 months in duration. The recognition, measurement, and presentation of expenses and cash flows arising from a lease by a lessee have not significantly changed from previous GAAP. There continues to be a differentiation between finance leases and operating leases, however, the principal difference from previous guidance is that the lease assets and lease liabilities arising from operating leases will be recognized on the balance sheets. For capital or finance leases, lessees will recognize amortization of the right-of-use asset separately from interest on the lease liability. For operating leases, lessees will recognize a single total lease expense. The standard is effective for public companies for the fiscal years and interim reporting periods beginning after December 15, 2018. We plan to adopt this new standard prospectively on January 1, 2019. We are evaluating the impact of the adoption of this standard, and expect that it will increase our lease assets and correspondingly increase our lease liabilities. In February 2018, the FASB issued ASU 2018-02, which allows companies to reclass stranded tax effects resulting from the Tax Cuts and Jobs Act of 2017 (2017 Act), from accumulated other comprehensive income to retained earnings. These stranded tax effects refer to the tax amounts included in accumulated other comprehensive income at the previous 35% U.S. statutory tax rate, for which the related deferred tax asset or liability was remeasured to the new 21% U.S. corporate statutory federal tax rate in the period of the 2017 Act enactment. The new standard is effective for fiscal years beginning after December 15, 2018, with early adoption permitted, and can be applied either in the period of adoption or retrospectively to each period impacted by the 2017 Act. We plan to adopt this standard prospectively on January 1, 2019. We are evaluating the impact of the adoption of this standard on the consolidated financial statements. In June 2018, the FASB issued ASU 2018-07 to reduce complexity and to improve financial reporting for share-based payments issued to non-employees. ASU 2018-07 expands the scope of Topic 718, Compensation-Stock Compensation (which currently only includes share-based payments to employees) to include share-based payments issued to non-employees for goods or services. Consequently, the accounting for share-based payments to non-employees and employees will be substantially aligned. ASU 2018-07 supersedes Subtopic 505-50, Equity-Based Payments to Non-Employees. ASU 2018-07 is effective for the Company for fiscal years beginning after December 15, 2018, including interim periods within that fiscal year and early adoption is permitted. We plan to adopt this standard prospectively on January 1, 2019. We are evaluating the impact of the adoption of this standard on the consolidated financial statements.

Net Loss Per Share

Net Loss Per Share	6 Months Ended
	Jun. 30, 2018
Earnings Per Share [Abstract]
Net Loss Per Share	Net Loss Per Share Basic net loss per share is computed by dividing net loss by the weighted-average number of shares of common stock outstanding during the period. Because of net losses recognized in each period, potential shares of common stock issuable upon the exercise of outstanding stock options have not been reflected in the calculation of diluted net loss per share due to the anti-dilutive effect. Diluted net loss per share, therefore, does not differ from basic net loss per share. The common stock equivalents issuable upon the exercise of the following dilutive securities have been excluded from the computation of diluted net loss per share attributable to common stockholders calculation because their effect would have been anti-dilutive for the periods presented: June 30, 2018 2017 (unaudited) (unaudited) Outstanding options to purchase common stock 4,976,842 4,142,900 Unvested restricted stock units 490,398 297,025 Total outstanding shares of common stock equivalents 5,467,240 4,439,925

Cash Equivalents and Short-Term

Cash Equivalents and Short-Term Investments	6 Months Ended
	Jun. 30, 2018
Investments, Debt and Equity Securities [Abstract]
Cash Equivalents and Short-Term Investments	Cash Equivalents and Short-Term Investments The amortized cost and fair value of our cash equivalents and short-term investments are as follows (in thousands): June 30, 2018 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value (unaudited) (unaudited) (unaudited) (unaudited) Money market funds $ 71,321 $ — $ — $ 71,321 U.S. Treasury securities 46,830 — (35 ) 46,795 Total $ 118,151 $ — $ (35 ) $ 118,116 Classified as: Cash equivalents $ 71,321 Short-term investments 46,795 Total $ 118,116 December 31, 2017 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Money market funds $ 70,502 $ — $ — $ 70,502 U.S. Treasury securities 68,702 — (49 ) 68,653 Total $ 139,204 $ — $ (49 ) $ 139,155 Classified as: Cash equivalents $ 70,502 Short-term investments 68,653 Total $ 139,155 All U.S. Treasury securities held as of June 30, 2018 and December 31, 2017 were classified as available-for-sale securities and had contractual maturities of less than one year. There were no realized gains or losses on these securities for the periods presented.

Fair Value of Financial Instrum

Fair Value of Financial Instruments	6 Months Ended
	Jun. 30, 2018
Fair Value Disclosures [Abstract]
Fair Value of Financial Instruments	Fair Value of Financial Instruments We measure and record cash and cash equivalents and short-term investments at fair value in the accompanying condensed consolidated financial statements. Fair value is defined as the exchange price that would be received for an asset or paid to transfer a liability, or 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. Valuation techniques used to measure fair value must maximize the use of observable inputs and minimize the use of unobservable inputs. The three-tier fair value hierarchy, which prioritizes the inputs used in measuring fair value, is as follows: Level 1 : Quoted prices in active markets for identical assets or liabilities. Level 2 : Observable inputs other than Level 1 prices, 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. Level 1 securities consist of highly liquid money market funds and U.S. Treasury securities. The fair value of Level 1 assets has been determined using quoted prices in active markets for identical assets. The following table summarizes our financial assets measured at fair value on a recurring basis (in thousands): June 30, 2018 LEVEL 1 LEVEL 2 LEVEL 3 TOTAL (unaudited) (unaudited) (unaudited) (unaudited) Assets: Money market funds $ 71,321 $ — $ — $ 71,321 U.S. Treasury securities 46,795 — — 46,795 Total $ 118,116 $ — $ — $ 118,116 December 31, 2017 LEVEL 1 LEVEL 2 LEVEL 3 TOTAL Assets: Money market funds $ 70,502 $ — $ — $ 70,502 U.S. Treasury securities 68,653 — — 68,653 Total $ 139,155 $ — $ — $ 139,155

Inventory

Inventory	6 Months Ended
	Jun. 30, 2018
Inventory Disclosure [Abstract]
Inventory	Inventory Inventory consists of the following (in thousands): June 30, 2018 December 31, 2017 (unaudited) Raw materials $ 16 $ — Work in process 757 541 Finished goods 127 143 Total inventory $ 900 $ 684

Accrued Liabilities

Accrued Liabilities	6 Months Ended
	Jun. 30, 2018
Payables and Accruals [Abstract]
Accrued Liabilities	Accrued Liabilities Accrued liabilities consist of the following (in thousands): June 30, 2018 December 31, 2017 (unaudited) Research and development services $ 2,888 $ 3,352 Employee compensation 1,794 2,777 Other 63 57 Total accrued liabilities $ 4,745 $ 6,186

Commitments and Contingencies

Commitments and Contingencies	6 Months Ended
	Jun. 30, 2018
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Operating Leases We lease laboratory and office space under an operating lease in Seattle, Washington. In January 2016, we entered into a new lease agreement for approximately 20,133 square feet of office and laboratory space, which includes and expands on the space we previously subleased. The lease commenced on January 1, 2017 with a term of five years and an option to extend the term for an additional three years. The annual base rent is $1.1 million for the first year and increases by 2.5% each year thereafter. Under the terms of this lease agreement, we provided a $200,000 security deposit in January 2017. In May 2017 , we entered into a sublease agreement with a third party subtenant. As sublandlord under this agreement, we are subleasing 5,048 square feet of the Seattle laboratory and office space for a period of three years. The annual base rent payable under this sublease is $273,000 for the first year and will increase by 2.5% each year thereafter. Rent under this sublease agreement is reflected in other income. We also lease 9,640 square feet of office space under an operating lease in South San Francisco, California. The lease commenced in January 2015 and continues through January 2020, with an option to extend for an additional five years . Under this lease, we were required to provide a $121,000 letter of credit as a security deposit. As of June 30, 2018 , no funds had been drawn on the letter of credit. Contingencies In June 2015, we entered into a clinical supply agreement with NanoPass Technologies LTD (NanoPass) for the use of its intradermal delivery device in certain of our clinical trials. In July 2015, in connection with the execution of the agreement, we paid an upfront fee of $600,000 for access and rights to use this device. In December 2015, we initiated a Phase 2 clinical trial using the device which triggered a milestone payment of $500,000 . Both the upfront fee and milestone payments were capitalized to prepaid expenses, and fully amortized to research and development expense as of December 31, 2017. In October 2016, we entered into a letter agreement with NanoPass, which amended our clinical supply agreement to expand the field of use to include all oncology immunotherapy applications, which provided for additional milestone payments to NanoPass upon achievement of future clinical milestones. Per the terms of the letter agreement, we paid NanoPass an additional upfront, one-time, non-refundable payment of $150,000 . In addition, we agreed to pay certain future milestone fees up to an aggregate of $8.8 million upon the achievement of certain clinical milestones. However, pursuant to our current clinical protocol, we do not plan to use the NanoPass intradermal delivery device in our Phase 3 clinical trial studying CMB305 in patients with synovial sarcoma. Under our license agreements with the Infectious Disease Research Institute (IDRI), we are contingently obligated to pay potential future milestone payments, which could total up to $2.3 million and $1.3 million , respectively, for the first and each subsequent exclusive licensed product we develop, and $1.3 million and $625,000 , respectively, for the first and each subsequent non-exclusive licensed product we develop. We are contingently obligated to pay potential future milestone payments to third parties as part of certain collaboration and licensing agreements, which could total up to $7.7 million in aggregate payments for the ZVex products we develop. We also have potential future royalty payments we may be required to make under our licensing agreements as described in Note 9.

License and Collaboration Agree

License and Collaboration Agreements	6 Months Ended
	Jun. 30, 2018
Research and Development [Abstract]
License and Collaboration Agreements	License and Collaboration Agreements Licenses Granted In August 2014, we entered into an agreement with Sanofi under which we granted Sanofi an exclusive license for the use of our GLAAS platform to discover, develop and commercialize products to treat peanut allergy. In 2014, Sanofi paid us an upfront payment under the license agreement of $3.5 million . We recognized no milestone revenue under this agreement for the three and six months ended June 30, 2018 and 2017 . The agreement provides for additional payments of up to $160.0 million based upon the attainment of certain development and commercialization milestones and tiered royalties on sales of approved products. Sanofi may terminate the agreement at any time upon six months’ written notice. We currently have two separate license agreements with MedImmune, LLC (MedImmune), entered into in October 2010, pursuant to which we granted MedImmune a worldwide, sublicensable, exclusive license to use GLA to develop and sell vaccines in two different infectious disease indications. Under the license agreements, MedImmune is obligated to use commercially reasonable efforts to develop and obtain regulatory approval for a licensed product in certain markets and to market and sell licensed products in any country where it obtains regulatory approval. In 2010, MedImmune paid us upfront payments under the license agreements of $4.5 million . Under each license agreement, MedImmune is obligated to make additional payments based on achievement of certain development, regulatory, and commercial milestones for the licensed indication. MedImmune is also obligated to pay us a low double-digit percentage share of non-royalty payments that it receives from sublicensees and a mid single-digit percentage royalty payment on net sales of licensed products, which royalty is subject to reduction under certain circumstances. Under each license agreement, MedImmune is obligated to make additional aggregate payments of $62.9 million to $72.5 million , depending on the infectious disease indication and the achievement of certain development, regulatory and commercial milestones for the licensed indication. We recognized no revenue for the achievement of development milestones under these license agreements for the three and six months ended June 30, 2018 and 2017 . We assessed these arrangements in accordance with Topic 606 and concluded that the contract counterparty, Sanofi and MedImmune are customers. Based on our assessment, we determined that the license was the only performance obligation at the inception of the agreements and the upfront fees were recognized in the period the arrangements were executed. Licenses Acquired In July 2008, we licensed certain patent rights, know-how and technology related to our GLAAS platform from the Infectious Disease Research Institute (IDRI), specifically products and formulations containing GLA and another synthetic TLR4 agonist referred to as SLA. This license was first amended and restated in 2010. In November 2015, we entered into a separate agreement with IDRI to license a patent related to our GLAAS technology in the field of cancer. Under this agreement, we paid IDRI an upfront license fee in the amount of $250,000 , which was recognized as research and development expense. Upon the achievement of certain developmental and regulatory milestones, we will be obligated to pay IDRI up to $250,000 and $125,000 , respectively, for the first and each subsequent licensed product we develop. In December 2015, we entered into a Second Amended and Restated License Agreement with IDRI, in which we obtained additional rights under the licensed technology, which rights vary by disease indication, and we returned to IDRI certain previously licensed GLA rights in select, primarily developing-world infectious disease indications. We received an exclusive license for SLA products in oncology, human allergy and addiction, as well as an option to obtain additional exclusive licenses in select infectious disease indications. In December 2015, in connection with the execution of the second restated agreement, we paid an upfront fee of $2.3 million , which was recorded as research and development expense. We are obligated to pay IDRI up to $2.3 million and $1.3 million , respectively, in additional payments for the first and each subsequent exclusive licensed product we develop, and $1.3 million and $625,000 , respectively, for the first and each subsequent non-exclusive licensed product we develop, based on the achievement of certain developmental and regulatory milestones. In addition, we will be obligated to pay certain commercialization milestones and royalty payments of single-digit percentage of net sales, if and when a licensed product is commercialized. We are also obligated to share with IDRI a percentage of payments received from any third-party sublicensees. Additionally, if we exercise our option for additional infectious disease indications, we will be required to make upfront, milestone and royalty payments for such additional indications, which payments are subject to similar terms and conditions as are applicable to other milestone and royalty payments. We recognized no IDRI license-related milestone fees for the three and six months ended June 30, 2018 and 2017 . In 2009, we licensed certain patent rights directed to the production of dendritic cell-targeted therapeutic and prophylactic immunization strategies from the California Institute of Technology (Caltech) in exchange for shares of our common stock valued at $25,000 . We made annual minimum royalty payments of $25,000 under the license until we recognized $100,000 in license-related milestone fees, expensed in research and development expenses for the year ended December 31, 2017. In addition, we agreed to pay certain fees in the future, including milestone payments upon achievement of certain development and commercialization milestones and royalty payments on net sales in the low single-digit percentage. We are required to pay Caltech up to an aggregate of $1.5 million in additional payments upon the achievement of certain regulatory and sales milestones. We recognized no Caltech milestone fees for the three and six months ended June 30, 2018 , and $100,000 for the three and six months ended June 30, 2017 . In June 2015, we entered into a clinical supply agreement with NanoPass for the use of their intradermal delivery device in certain of our clinical trials. See Note 8 for additional information. In October 2016, we entered into a license agreement with TheraVectys SA (TVS), pursuant to which we received a field limited, non-exclusive, sublicensable license for oncology uses to certain current and future intellectual property rights owned, controlled and licensed by TVS relating to lentiviral vector technologies. We will owe TVS milestone payments based on the achievement of certain development and regulatory milestones for each licensed product, in the aggregate amount of up to $5.8 million , except that the first two milestones payments are waived for CMB305/LV305. In addition, we will be obligated to pay a single commercial milestone payment for each product that achieves a specified net sales amount. We will owe royalties to TVS on product sales that are made directly by us or our affiliates, subject to certain royalty-offset provisions. For the first four products, including LV305/CMB305, royalties will be based on a low-single digit percentage of net sales, and for subsequent products, tiered royalties will be based on low-to-mid-single digit percentages of net sales. TVS will also receive a mid-single digit percentage of revenues that we receive for sublicensing the licensed intellectual property. We recognized no TVS milestone fees for the three and six months ended June 30, 2018 and 2017 . Collaborations In October 2014, we entered into a collaboration with Sanofi Pasteur for the development of a Herpes Simplex Virus (HSV) immune therapy. Sanofi Pasteur and Immune Design are each contributing product candidates to the collaboration: Sanofi Pasteur is contributing HSV-529, a clinical-stage replication-defective HSV vaccine product candidate, and we contribute G103, our preclinical trivalent vaccine product candidate. The collaboration will explore the potential of various combinations of agents, including leveraging our GLAAS platform, with the goal to select the best potential immune therapy for patients. Each company will develop the products jointly through Phase 2 clinical trials, at which point Sanofi Pasteur intends to continue development of the most promising candidate and be responsible for commercialization. Sanofi Pasteur will bear the costs of all preclinical and clinical development, with Immune Design providing a specific formulation of GLA from the GLAAS platform at its cost through Phase 2 studies. Immune Design will be eligible to receive future milestone and royalty payments on any licensed product developed from the collaboration. We recognize funding from collaborative research and development efforts as revenue as we perform or deliver the related services in accordance with contract terms as long as we will receive payment for such services upon standard payment terms. The costs of the related services performed are recorded as research and development expenses on the condensed consolidated statements of operations and comprehensive loss. Under this collaboration arrangement, we recognized revenue of $311,000 and $681,000 for the three months ended June 30, 2018 and 2017 , respectively, and $807,000 and $5.9 million for the six months ended June 30, 2018 and 2017 , respectively. As of June 30, 2018 and December 31, 2017 , we had an outstanding net unbilled receivable of $406,000 and $605,000 , respectively, due from Sanofi Pasteur on our accompanying condensed consolidated balance sheets related to this agreement. The net unbilled receivable represents collaboration research services earned, but not yet billed to Sanofi Pasteur as of June 30, 2018 and December 31, 2017 . We assessed the arrangement in accordance with Topic 606 and concluded that the counterparty Sanofi Pasteur is a customer. Based on our assessment, we determined that the research and development services are the only performance obligation at the inception of the agreement. There was no day one license fee paid by Sanofi Pasteur and Sanofi Pasteur pays fair value for the research and development services provided.

Stockholders' Equity

Stockholders' Equity	6 Months Ended
	Jun. 30, 2018
Equity [Abstract]
Stockholders' Equity	Stockholders’ Equity Preferred Stock Our board of directors has the authority to fix and determine and to amend the number of shares of any series of preferred stock that is wholly unissued or to be established and to fix and determine and to amend the designation, preferences, voting powers and limitations, and the relative, participating, optional or other rights, of any series of shares of preferred stock that is wholly unissued or to be established. There was no preferred stock issued and outstanding as of June 30, 2018 or December 31, 2017 . Common Stock We had 48,164,828 and 48,068,650 shares of common stock outstanding as of June 30, 2018 and December 31, 2017 , respectively. Shares of common stock reserved for future issuance were as follows: June 30, December 31, (unaudited) Shares available for issuance under the employee stock purchase plan 435,565 475,010 Options granted and outstanding 4,976,842 4,094,532 Unvested restricted stock awards 490,398 195,172 Shares available for future stock option grants and restricted stock awards 1,635,676 947,199 Shares reserved for future issuance under equity incentive plans 7,538,481 5,711,913 In July 2017, we entered into a Sales Agreement (ATM Agreement) with Cowen and Company, LLC (Cowen) under which we may offer and sell, from time to time at our sole discretion through Cowen, as our sales agent, shares of our common stock having an aggregate offering price of up to $50.0 million . Cowen may sell the common stock by any method permitted by law deemed to be an “at the market offering” as defined in Rule 415(a)(4) of the Securities Act of 1933, as amended, including sales made directly on or through the Nasdaq Global Market (Nasdaq) or on any other existing trading market for our common stock. Any common stock sold will be issued pursuant to our shelf registration statement on Form S-3 (File No. 333-206324). We will pay Cowen a commission equal to 3.0% of the gross sales proceeds of any common stock sold under the ATM Agreement and also have provided Cowen with indemnification and contribution rights. To date, we have not sold any common stock under the ATM Agreement. Equity Incentive Plans Under our 2014 Omnibus Incentive Plan (2014 Plan), the total number of shares of common stock available for issuance increases annually on January 1 of each year in an amount equal to 4% of the total number of shares of our common stock issued and outstanding as of December 31 of the immediately preceding year, or such lesser amount as deemed appropriate by our Board of Directors. On January 1, 2018 , the authorized shares available under the 2014 Plan were increased by 1,922,746 shares. There were a total of 5,837,813 shares of common stock authorized under the 2014 Plan as of June 30, 2018 . Under our 2014 Employee Stock Purchase Plan (2014 ESPP), the total number of shares of common stock available for issuance increases annually on January 1 of each year in an amount equal to the lesser of (i) 1% of the total number of shares issued and outstanding as of December 31 of the immediately preceding year, (ii) 200,000 shares, or such lesser amount as deemed appropriate by our Board of Directors. For 2018 , the Board of Directors determined the current shares available for issuance under the 2014 ESPP were sufficient and did not increase the amount of authorized shares. There were a total of 435,565 shares of common stock authorized under the 2014 ESPP as of June 30, 2018 . Restricted Stock Units In January 2018, the Compensation Committee of our Board of Directors granted 198,835 time-based restricted stock units (RSUs) and 367,500 performance-based restricted stock units (PSUs) to our employees. Restricted stock units are awards that entitle the holder to receive shares of our common stock upon vesting. The RSUs and PSUs cannot be transferred and are subject to forfeiture if the holder’s employment terminates prior to vesting. One-third of the RSUs granted in January 2018 will vest on each anniversary of the grant date over three ( 3 ) years, subject to the employee’s continued service with us on each vesting date. The fair value of each RSU is equal to the closing price of our common stock on the applicable grant date. Fifty percent of the PSUs would vest on each of June 30, 2018 and December 31, 2018 upon the achievement of certain performance criteria by such date, subject to the employee’s continued service with us on each vesting date. If the performance criteria are not met by the specified dates, the corresponding PSUs will expire. Stock-based compensation for these PSUs is recognized over the service period beginning in the period management determines it is probable that the performance criteria will be achieved. During the period ending March 31, 2018, we began recognizing stock compensation expense on the PSUs as the outcome of the performance criteria being achieved was deemed probable. As of June 30, 2018, 183,750 PSUs of the PSUs that were granted in January 2018 have expired unvested as the performance criteria was not met by the specified date. In addition, management has determined that the performance criteria associated with the remaining PSUs that were granted in January 2018 will not be achieved by the specified date due to a change in program strategy, and we have reversed the related stock-based compensation expense of $508,000 recorded in prior quarter. Summary of RSUs and PSUs information is as follows: SHARES WEIGHTED AVERAGE GRANT DATE FAIR VALUE (per share) Outstanding at December 31, 2017 195,172 $ 10.99 Granted (unaudited) 566,335 4.04 Vested (unaudited) (55,135 ) 11.96 Forfeited (unaudited) (215,974 ) 4.33 Outstanding at June 30, 2018 (unaudited) 490,398 5.78 Stock Option Activity Summary of stock option information is as follows: OPTIONS OUTSTANDING WEIGHTED- AVERAGE EXERCISE PRICE WEIGHTED- AVERAGE REMAINING CONTRACT TERM (in years) AGGREGATE INTRINSIC VALUE (in thousands) Outstanding at December 31, 2017 4,094,532 $ 10.96 7.21 $ 2,771 Granted (unaudited) 1,198,020 $ 3.98 Exercised (unaudited) (1,598 ) $ 1.15 Expired (unaudited) (188,493 ) $ 13.76 Forfeited (unaudited) (125,619 ) $ 8.68 Outstanding at June 30, 2018 (unaudited) 4,976,842 $ 9.23 7.42 $ 3,940 Exercisable as of June 30, 2018 (unaudited) 2,774,538 $ 10.74 6.25 $ 3,281 As of June 30, 2018 , there was $9.5 million of total unrecognized stock-based compensation expense related to nonvested stock options that is expected to be recognized over a weighted-average period of 2.0 years . The total intrinsic value of options exercised during the six months ended June 30, 2018 and 2017 was $4,000 and $544,000 , respectively. Stock-Based Compensation Expense Prior to the adoption of ASU No. 2016-09 on January 1, 2017, employee stock-based compensation expense recognized was calculated based on awards ultimately expected to vest and was reduced for estimated forfeitures. Effective January 1, 2017, upon our adoption of ASU No. 2016-09, we have elected to account for forfeitures as they occur. Total stock-based compensation expense recognized in our condensed consolidated statements of operations and comprehensive income (loss) is as follows (in thousands): Three Months Ended June 30, Six Months Ended June 30, 2018 2017 2018 2017 (unaudited) (unaudited) (unaudited) (unaudited) Employee: Research and development $ 688 $ 904 $ 1,888 $ 1,837 General and administrative 808 1,242 2,333 2,522 Non-Employee: Research and development 14 34 23 57 General and administrative 1 25 5 36 Total stock-based compensation expense $ 1,511 $ 2,205 $ 4,249 $ 4,452 We use the Black-Scholes option pricing model to estimate the fair value of stock options at the grant date. The fair values of stock options granted to employees were calculated using the following assumptions: Three Months Ended June 30, Six Months Ended June 30, 2018 2017 2018 2017 (unaudited) (unaudited) (unaudited) (unaudited) Weighted-average estimated fair value $2.75 $4.86 $2.69 $3.93 Risk-free interest rate 2.8% - 2.9% 1.9% - 2.0% 2.3% - 2.9% 1.9% - 2.1% Expected term of options (in years) 6.08 6.08 5.50 - 6.08 5.50 - 6.08 Expected stock price volatility 78% 80% 78% 80% - 82% Expected dividend yield — — — — Stock Option Exchange Program Pursuant to the Offer to Exchange Eligible Options for New Options, dated June 18, 2018 (Exchange Offer), we commenced a tender offer for our employees, including executive officers, to exchange eligible stock options for replacement stock options with modified terms. Employees who held outstanding stock options granted on or before December 31, 2017 with an exercise price equal to or greater than $5.00 per share (Eligible Options) were given an opportunity to tender each Eligible Option in exchange for a new stock option with modified terms (New Options). Pursuant to the Exchange Offer, each New Option would: • have an exercise price equal to the greater of $4.10 per share or the closing price of our common stock as reported on Nasdaq on the date the New Option was granted (Grant Date); • vest in equal monthly amounts over either two or three years, depending on whether the tendered Eligible Option was granted on or before or after December 31, 2016, respectively; • have a maximum term of seven years; • be an incentive stock option (ISO) to the greatest extent permitted by applicable law; and • be exercisable for a reduced number of shares based on the following exchange ratios: Eligible Option Exercise Price Ranges Exchange Ratio (Surrendered Eligible Options: New Options)* $5.00-$14.99 1.50 to 1 $15.00-$29.99 1.75 to 1 $30.00-And Up 2.00 to 1 * Rounded up to the nearest share The Exchange Offer expired at 6:00 p.m., Pacific time, on July 17, 2018. Pursuant to the Exchange Offer, 31 employees elected to exchange outstanding stock options, and we accepted for cancellation, stock options to purchase an aggregate of 1,590,083 shares of common stock, representing approximately 65% of the total shares of common stock underlying the Eligible Options. On July 17, 2018, immediately following the expiration of the Exchange Offer, we granted New Options to purchase 962,099 shares of common stock, each with an exercise price of $4.40 per share, which was the closing price per share of our common stock on Nasdaq on the Grant Date. As a result, 627,984 shares of common stock returned to the 2014 Plan and became available for future issuance. The exchange of stock options was treated as a modification for accounting purposes. The incremental expense for vested stock options calculated using the Black-Scholes option pricing model will be recorded in our financial statements for the quarter ending September 30, 2018. The incremental expense together with the unamortized expense remaining on the unvested options will be amortized over the vesting period of the New Options beginning on July 17, 2018.

Income Taxes

Income Taxes	6 Months Ended
	Jun. 30, 2018
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes On December 22, 2017, the Tax Cuts and Jobs Act of 2017 (Tax Act) was signed into law. Although the Tax Act is generally effective January 1, 2018, GAAP requires recognition of the tax effects of new legislation during the reporting period that includes the enactment date, which was December 22, 2017. The Company has adjusted its deferred tax assets and liabilities based on the reduction of the U.S. federal corporate tax rate from 35% to 21% and assessed the realizability of our deferred tax assets based on our current understanding of the provisions of the Tax Act. The primary impact of the Tax Act resulted from the re-measurement of deferred tax assets and liabilities due to the change in the corporate tax rate, reducing our deferred tax assets by $30.5 million with a corresponding reduction in our valuation allowance. Overall, this had a net zero effect on our effective tax rate for the year as the Company has a full valuation allowance against its deferred tax assets and is currently in a taxable loss. We consider our accounting for the impacts of the Tax Act to be incomplete and the Company will continue to assess the impact of the Tax Act (and expected further guidance from federal and state tax authorities as well as further guidance for the associated income tax accounting) on our business and consolidated financial statements over the next 12 months. Additional work will be necessary for a more detailed analysis of our deferred tax assets and liabilities as well as potential correlative adjustments. We do not expect any material subsequent adjustments to these amounts. Adjustments, if any, are not expected to have any impact to our results of operations due to our loss position and valuation allowance. As of June 30, 2018 , we have not yet completed our accounting for all the tax effects of the Tax Act, however, as noted above we have made a reasonable estimate of the effects on our existing deferred tax balances. In all cases, we will continue to make and refine our calculations as additional analysis is completed. In addition, our provisional estimates may also be adjusted as we gain a more thorough understanding of the tax law.

Legal Proceedings

Legal Proceedings	6 Months Ended
	Jun. 30, 2018
Loss Contingency [Abstract]
Legal Proceedings	Legal Proceedings Settlement and License Agreements with TheraVectys SA On October 17, 2016, we entered into a Settlement Agreement and a License Agreement with TheraVectys SA (TVS) obtaining certain present and future intellectual property rights and resolving the litigation that TVS initiated against us in the Chancery Court of the State of Delaware in July 2014, as well as related claims and counterclaims. In the proceeding, TVS had alleged that it had entered into a contractual relationship with Henogen SA (Henogen) in 2010 with respect to the production of lentiviral vector vaccines for TVS. Henogen is a contract manufacturing organization with which we contracted for the manufacture of our LV305 product candidate. TVS alleged that its contractual relationship with Henogen contained an exclusivity provision limiting Henogen’s ability to participate in the manufacturing process of a vaccine based on lentiviral DNA vectors for third parties. TVS alleged that we entered into a contractual relationship with Henogen to manufacture lentiviral vectors, which TVS contends interfered with its contract with Henogen and resulted in the use of certain TVS confidential information and trade secrets. The complaint asserted four counts for relief: tortious interference with contractual relationship, unfair competition, misappropriation of trade secrets, and unjust enrichment. Claimed damages were not specified. Under the Settlement Agreement, TVS agreed to dismiss all pending litigation against us and to withdraw its patent opposition proceedings (EPO Proceeding) against our European Patent No EP 2 456 786 (EU Patent). Also under the Settlement Agreement, both parties agreed to a broad release of claims against one another based on acts or omissions arising out of the litigation, or the facts and circumstances giving rise to the litigation. Neither party made any admission of liability or wrongdoing under the Settlement Agreement. In addition, the License Agreement provides us with a field limited, non-exclusive, sublicensable license for oncology uses to certain current and future intellectual property rights owned, controlled and licensed by TVS. As a non-contingent fee for a license to certain present and future intellectual property of TVS, and in consideration for the settlement of all claims and disputes between the parties, we paid $6.0 million into an escrow account (Escrowed Payment), and we also agreed to pay $1.25 million to TVS when we next raised $25.0 million , in the aggregate, through equity sales, debt or licensing revenue. The Escrowed Payment was to be disbursed to TVS as follows: (a) fifty percent ( 50% ) when (i) Institut Pasteur consented to the granting by TVS to us of a sublicense to certain patents licensed by TVS and (ii) the litigation in the United States and Belgium had been dismissed; and (b) fifty percent ( 50% ) upon the final resolution of the EPO Proceeding if the scope of the EU Patent remained unchanged (Escrow Conditions); provided, that delays in satisfying the Escrow Conditions would potentially result in a reduction of the amount of the Escrowed Payment that would be disbursed to TVS. After entering into the Settlement Agreement, we determined that the aggregate payment amount expected to be paid to TVS was $7.25 million and as such, the aggregate payment amount should be allocated between (1) dismissal of the litigation; and (2) license to current and future TVS intellectual property (IP). As we were not able to reliably estimate the fair value of the litigation dismissal, we assigned a fair value to the aggregate amount of the license to current and future TVS IP through the use of a benchmarking approach and determined the fair value of the license to current and future IP obtained from TVS by benchmarking this deal against similar recent (within the last 5 years) deals within our industry. The metrics we used in our benchmarking approach included similarities in industry, product type, therapeutic area, stage of product development and exclusivity. Based upon the results of our benchmark approach, we determined that the fair value assigned to the license to current and future TVS IP to be $1.4 million with the remaining residual amount of $5.85 million allocated to the dismissal of the litigation. For the year ended December 31, 2016, the $5.85 million allocated to the dismissal of litigation was recorded as a general and administrative expense, and the $1.4 million allocated to the license was recorded as a research and development expense on the condensed consolidated statements of operations and comprehensive income (loss). In November 2017, we paid $1.25 million to TVS upon completion of an underwritten public offering in which we raised net proceeds of $86.6 million , after deducting underwriting discounts, commissions and offering expenses. In February 2018, the parties came to an agreement on the timing and satisfaction of the Escrow Conditions, and the escrow agent disbursed $5.25 million of the Escrowed Payment to TVS and $750,000 of the Escrowed Payment to Immune Design. The $750,000 recoupment of the Escrow Payment by the Company was recognized during the period ended March 31, 2018 as a reduction to general and administrative expenses. No additional payments are expected to be made under the terms of the Settlement Agreement.

Subsequent Event

Subsequent Event	6 Months Ended
	Jun. 30, 2018
Subsequent Events [Abstract]
Subsequent Event	Subsequent Event The Exchange Offer commenced on June 18, 2018 and expired on July 17, 2018. See Note 10 for additional information on the Exchange Offer.

Summary of Significant Accoun20

Summary of Significant Accounting Policies (Policies)	6 Months Ended
	Jun. 30, 2018
Accounting Policies [Abstract]
Basis of Presentation and Use of Estimates	Basis of Presentation and Use of Estimates The accompanying condensed consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles (GAAP). To conform with GAAP, the preparation of our financial statements requires management to make judgments, assumptions, and estimates that affect the amounts reported in our condensed consolidated financial statements and accompanying notes. Estimates are used for, but not limited to, accruals for clinical trial activity, other accrued liabilities, and assumptions used in determining stock-based compensation expenses. We base our estimates on historical experience and on various other assumptions that we believe to be reasonable. Actual results could differ materially from those estimates.
Principles of Consolidation	Principles of Consolidation Our condensed consolidated financial statements include the financial position and results of operations of Immune Design Corp. and Immune Design Ltd., our wholly owned subsidiary. Immune Design Ltd. was incorporated in the United Kingdom in February 2016, and to date, there have been no financial transactions or balances related to this entity.
Short-Term Investments	Short-Term Investments Our short-term investments include funds invested in U.S. Treasury securities with a final maturity of each security of less than one year. All investments are classified as available-for-sale securities and are recorded at fair value based on quoted prices in active markets, with unrealized gains and losses excluded from earnings and reported in other comprehensive income (loss). Purchase premiums and discounts are recognized in interest income using the interest method over the terms of the securities. Realized gains and losses and declines in fair value that are deemed to be other than temporary are reflected in the condensed consolidated statements of operations and comprehensive income (loss) using the specific-identification method.
Restricted Cash	Restricted Cash Restricted cash includes funds used to secure our obligations associated with the settlement of all claims and disputes under our Settlement Agreement with TheraVectys SA (TVS). A deposit of zero and $6.0 million was held in escrow restricted from withdrawal as of June 30, 2018 and December 31, 2017 , respectively. See Note 12 for additional information. In addition, we held a security deposit under a standby letter of credit associated with our laboratory and office space lease in Seattle, Washington, to be drawn down by our landlord if the lease is breached. The security deposit is classified as a non-current asset on our Condensed Consolidated Balance Sheets.
Comprehensive Loss	Comprehensive Loss Comprehensive loss is composed of net loss and other comprehensive income or loss that are excluded from net loss. For the periods presented, other comprehensive income consists of unrealized gains on our available-for-sale securities.
Revenue Recognition	Revenue Recognition Effective January 1, 2018, we adopted Accounting Standards Codification (ASC) Topic 606, Revenue from Contracts with Customers , using the modified retrospective method and there was no impact to our financial position and results of operations as a result of the adoption. This standard applies to all contracts with customers, except for contracts that are within the scope of other standards, such as leases, insurance, collaboration arrangements and financial instruments. Under Topic 606, an entity recognizes revenue when its customer obtains control of promised goods or services, in an amount that reflects the consideration which the entity expects to receive in exchange for those goods or services. To determine revenue recognition for arrangements that an entity determines are within the scope of Topic 606, the entity performs the following five steps: (i) identify the contract(s) with a customer; (ii) identify the performance obligations in the contract; (iii) determine the transaction price; (iv) allocate the transaction price to the performance obligations in the contract; and (v) recognize revenue when (or as) the entity satisfies a performance obligation. We only apply the five-step model to contracts when it is probable that the entity will collect the consideration it is entitled to in exchange for the goods or services it transfers to the customer. At contract inception, once the contract is determined to be within the scope of Topic 606, we assess the goods or services promised within each contract and determine those that are performance obligations, and assess whether each promised good or service is distinct. We then recognize as revenue the amount of the transaction price that is allocated to the respective performance obligation when (or as) the performance obligation is satisfied. We derive our revenue from collaboration and licensing agreements and the sale of products associated with material transfer, collaboration and supply agreements. License, Collaboration and Other Revenues We enter into collaboration and out-licensing agreements which are within the scope of Topic 606, under which we perform research and development activities and license certain rights to our intellectual property to third parties. The terms of these arrangements typically include payment to us of one or more of the following: non-refundable, up-front license fees; development, regulatory and commercial milestone payments; payments for manufacturing supply services we provide through our contract manufacturers; and royalties on net sales of licensed products. Each of these payments results in license, collaboration and other 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 we fulfill our obligations under each of these agreements, we perform the following steps: (1) 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) we satisfy each performance obligation. As part of the accounting for these arrangements, we must develop assumptions that require judgment to determine the stand-alone selling price for each performance obligation identified in the contract. We use key assumptions to determine the stand-alone selling price, which may include forecasted revenues, development timelines, reimbursement rates for personnel costs, discount rates and probabilities of technical and regulatory success. Licensing of intellectual property. If the license to our intellectual property is determined to be distinct from the other performance obligations identified in the arrangement, we recognize revenue 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, we utilize 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. We evaluate the measure of progress each reporting period and, if necessary, adjust the measure of performance and related revenue recognition. Milestone payments . At the inception of each arrangement that includes development milestone payments, we evaluate whether the milestones are considered probable of being reached and estimate 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 our control 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 we recognize revenue as or when the performance obligations under the contract are satisfied. At the end of each subsequent reporting period, we re-evaluate the probability of achievement of such development milestones and any related constraint, and if necessary, adjust our estimate of the overall transaction price. Any such adjustments are recorded on a cumulative catch-up basis, which would affect license, collaboration and other revenues and earnings in the period of adjustment. Manufacturing supply services. Arrangements that include a promise for future supply of drug substance or drug product for either clinical development or commercial supply at the customer’s discretion are generally considered as options. We assess if these options provide material rights to the licensee and if so, they are accounted for as separate performance obligations. If we are entitled to additional payments when the customer exercises these options, any additional payments are recorded when the customer obtains control of the goods, which is upon shipment. Royalties. Arrangements that include sales-based royalties, including milestone payments based on the level of sales, and the license is deemed to be the predominant item to which the royalties relate, we recognize 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, we have not recognized any royalty revenue resulting from any of our collaboration or out-licensing agreements. Product Sales Revenue from product sales of glucopyranosyl lipid A (GLA), a product from our GLAAS platforms, is recognized when the Customer obtains control of the Company’s product, which occurs at a point in time, typically upon shipment to the Customer. All revenues associated from the sale of GLA products supplied by us are reported under product sales with the applicable costs reported under cost of product sales. Product sales consist of the direct costs associated with the manufacture and formulation of GLA, including costs to purchase raw materials, third-party contract manufacturing costs, assay testing and ongoing product stability testing.
Accrued Liabilities and Research and Development Related Accruals	Accrued Liabilities and Research and Development Related Accruals Accrued liabilities and research and development related accruals represent accrued compensation including vacation accruals and accrued expenses. As part of the process of preparing our consolidated financial statements, we are required to estimate our accrued professional services and research and development expenses. This process involves reviewing contracts and vendor agreements, communicating with appropriate internal personnel to identify services that have been performed on our behalf and estimating the associated cost incurred for the service when we have not yet been invoiced or otherwise notified of actual cost. We make estimates of our accrued expenses as of each balance sheet date in our consolidated financial statements based on facts and circumstances known to us and periodically confirming the accuracy of our estimates with service providers and making adjustments, if necessary. We base our expenses related to contract manufacturing and clinical studies on our estimates of the services received and efforts expended pursuant to contracts with multiple contract manufacturing organizations and clinical research organizations that conduct and manage supply and clinical studies on our behalf. The financial terms of these agreements vary from contract to contract and may result in uneven payment flows. In accruing service fees, we estimate the time period over which services will be performed and the level of effort to be expended in each period. If the actual timing of the performance of services or the level of effort varies from our estimate, we adjust the accrual accordingly. Although we do not expect our estimates to be materially different from amounts actually incurred, if our estimates of the status and timing of services performed differ from the actual status and timing of services performed, we may report amounts that are too high or too low in any particular period. Accounting estimates and judgments related to contract manufacturing activities and clinical trials are inherently uncertain. We base our estimates on the best information available at the time. As appropriate, estimates are assessed periodically and updated to reflect current information and any changes will generally be reflected in the period first identified. To date, we have not experienced any significant adjustments to our estimates.
Recent Accounting Pronouncements	Recently Adopted Accounting Pronouncements In August 2016, the Financial Accounting Standards Board (FASB) issued ASU No. 2016-15 which provides new guidance on the classification of certain cash receipts and payments in the statement of cash flows. The new guidance is intended to reduce diversity in practice in how certain transactions are classified in the statement of cash flows. We adopted the new standard in the first quarter of 2018. Adoption of this standard did not have a material impact on our consolidated financial statements. In November 2016, the FASB issued ASU No. 2016-18 that relates to restricted cash. The new guidance requires amounts generally described as restricted cash and restricted cash equivalents should be included with cash and cash equivalents when reconciling the beginning-of-period and end-of-period total amounts shown on the statement of cash flows. We adopted the new standard in the first quarter of 2018. Adoption of this standard did not have a material impact on our consolidated financial statements. In May 2017, the FASB issued ASU No. 2017-09 to provide clarity and reduce both diversity in practice and cost and complexity when applying the guidance in Topic 718 about a change to the terms and conditions of a share-based payment award. The amendments in this update provide guidance about which changes to the terms or conditions of a share-based payment award require an entity to apply modification accounting in Topic 718. We adopted the new standard in the first quarter of 2018. Adoption of this standard did not have a material impact on our consolidated financial statements. Recent Accounting Pronouncements In February 2016, the FASB issued ASU 2016-02 related to lease accounting. This standard will require organizations that lease assets to recognize on the balance sheet the assets and liabilities for the rights and obligations created by those leases that are greater than 12 months in duration. The recognition, measurement, and presentation of expenses and cash flows arising from a lease by a lessee have not significantly changed from previous GAAP. There continues to be a differentiation between finance leases and operating leases, however, the principal difference from previous guidance is that the lease assets and lease liabilities arising from operating leases will be recognized on the balance sheets. For capital or finance leases, lessees will recognize amortization of the right-of-use asset separately from interest on the lease liability. For operating leases, lessees will recognize a single total lease expense. The standard is effective for public companies for the fiscal years and interim reporting periods beginning after December 15, 2018. We plan to adopt this new standard prospectively on January 1, 2019. We are evaluating the impact of the adoption of this standard, and expect that it will increase our lease assets and correspondingly increase our lease liabilities. In February 2018, the FASB issued ASU 2018-02, which allows companies to reclass stranded tax effects resulting from the Tax Cuts and Jobs Act of 2017 (2017 Act), from accumulated other comprehensive income to retained earnings. These stranded tax effects refer to the tax amounts included in accumulated other comprehensive income at the previous 35% U.S. statutory tax rate, for which the related deferred tax asset or liability was remeasured to the new 21% U.S. corporate statutory federal tax rate in the period of the 2017 Act enactment. The new standard is effective for fiscal years beginning after December 15, 2018, with early adoption permitted, and can be applied either in the period of adoption or retrospectively to each period impacted by the 2017 Act. We plan to adopt this standard prospectively on January 1, 2019. We are evaluating the impact of the adoption of this standard on the consolidated financial statements. In June 2018, the FASB issued ASU 2018-07 to reduce complexity and to improve financial reporting for share-based payments issued to non-employees. ASU 2018-07 expands the scope of Topic 718, Compensation-Stock Compensation (which currently only includes share-based payments to employees) to include share-based payments issued to non-employees for goods or services. Consequently, the accounting for share-based payments to non-employees and employees will be substantially aligned. ASU 2018-07 supersedes Subtopic 505-50, Equity-Based Payments to Non-Employees. ASU 2018-07 is effective for the Company for fiscal years beginning after December 15, 2018, including interim periods within that fiscal year and early adoption is permitted. We plan to adopt this standard prospectively on January 1, 2019. We are evaluating the impact of the adoption of this standard
Net Loss Per Share	Basic net loss per share is computed by dividing net loss by the weighted-average number of shares of common stock outstanding during the period. Because of net losses recognized in each period, potential shares of common stock issuable upon the exercise of outstanding stock options have not been reflected in the calculation of diluted net loss per share due to the anti-dilutive effect. Diluted net loss per share, therefore, does not differ from basic net loss per share.
Fair Value Measurement	We measure and record cash and cash equivalents and short-term investments at fair value in the accompanying condensed consolidated financial statements. Fair value is defined as the exchange price that would be received for an asset or paid to transfer a liability, or 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. Valuation techniques used to measure fair value must maximize the use of observable inputs and minimize the use of unobservable inputs. The three-tier fair value hierarchy, which prioritizes the inputs used in measuring fair value, is as follows: Level 1 : Quoted prices in active markets for identical assets or liabilities. Level 2 : Observable inputs other than Level 1 prices, 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. Level 1 securities consist of highly liquid money market funds and U.S. Treasury securities. The fair value of Level 1 assets has been determined using quoted prices in active markets for identical assets.

Net Loss Per Share (Tables)

Net Loss Per Share (Tables)	6 Months Ended
	Jun. 30, 2018
Earnings Per Share [Abstract]
Common Stock Issuable Upon the Conversion or Exercise of Dilutive Securities Excluded from Diluted Net Loss Per Share Attributable to Common Stockholders	The common stock equivalents issuable upon the exercise of the following dilutive securities have been excluded from the computation of diluted net loss per share attributable to common stockholders calculation because their effect would have been anti-dilutive for the periods presented: June 30, 2018 2017 (unaudited) (unaudited) Outstanding options to purchase common stock 4,976,842 4,142,900 Unvested restricted stock units 490,398 297,025 Total outstanding shares of common stock equivalents 5,467,240 4,439,925

Cash Equivalents and Short-Te22

Cash Equivalents and Short-Term Investments (Tables)	6 Months Ended
	Jun. 30, 2018
Investments, Debt and Equity Securities [Abstract]
Cash and Cash Equivalents and Short-term Investments	The amortized cost and fair value of our cash equivalents and short-term investments are as follows (in thousands): June 30, 2018 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value (unaudited) (unaudited) (unaudited) (unaudited) Money market funds $ 71,321 $ — $ — $ 71,321 U.S. Treasury securities 46,830 — (35 ) 46,795 Total $ 118,151 $ — $ (35 ) $ 118,116 Classified as: Cash equivalents $ 71,321 Short-term investments 46,795 Total $ 118,116 December 31, 2017 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Money market funds $ 70,502 $ — $ — $ 70,502 U.S. Treasury securities 68,702 — (49 ) 68,653 Total $ 139,204 $ — $ (49 ) $ 139,155 Classified as: Cash equivalents $ 70,502 Short-term investments 68,653 Total $ 139,155

Fair Value of Financial Instr23

Fair Value of Financial Instruments (Tables)	6 Months Ended
	Jun. 30, 2018
Fair Value Disclosures [Abstract]
Financial Assets Measured at Fair Value on a Recurring Basis	The following table summarizes our financial assets measured at fair value on a recurring basis (in thousands): June 30, 2018 LEVEL 1 LEVEL 2 LEVEL 3 TOTAL (unaudited) (unaudited) (unaudited) (unaudited) Assets: Money market funds $ 71,321 $ — $ — $ 71,321 U.S. Treasury securities 46,795 — — 46,795 Total $ 118,116 $ — $ — $ 118,116 December 31, 2017 LEVEL 1 LEVEL 2 LEVEL 3 TOTAL Assets: Money market funds $ 70,502 $ — $ — $ 70,502 U.S. Treasury securities 68,653 — — 68,653 Total $ 139,155 $ — $ — $ 139,155

Inventory (Tables)

Inventory (Tables)	6 Months Ended
	Jun. 30, 2018
Inventory Disclosure [Abstract]
Inventory	Inventory consists of the following (in thousands): June 30, 2018 December 31, 2017 (unaudited) Raw materials $ 16 $ — Work in process 757 541 Finished goods 127 143 Total inventory $ 900 $ 684

Accrued Liabilities (Tables)

Accrued Liabilities (Tables)	6 Months Ended
	Jun. 30, 2018
Payables and Accruals [Abstract]
Schedule of Accrued Liabilities	Accrued liabilities consist of the following (in thousands): June 30, 2018 December 31, 2017 (unaudited) Research and development services $ 2,888 $ 3,352 Employee compensation 1,794 2,777 Other 63 57 Total accrued liabilities $ 4,745 $ 6,186

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	6 Months Ended
	Jun. 30, 2018
Equity [Abstract]
Schedule of Shares of Common Stock Reserved for Future Issuance	Shares of common stock reserved for future issuance were as follows: June 30, December 31, (unaudited) Shares available for issuance under the employee stock purchase plan 435,565 475,010 Options granted and outstanding 4,976,842 4,094,532 Unvested restricted stock awards 490,398 195,172 Shares available for future stock option grants and restricted stock awards 1,635,676 947,199 Shares reserved for future issuance under equity incentive plans 7,538,481 5,711,913
Schedule of Restricted Stock Unit Activity	Summary of RSUs and PSUs information is as follows: SHARES WEIGHTED AVERAGE GRANT DATE FAIR VALUE (per share) Outstanding at December 31, 2017 195,172 $ 10.99 Granted (unaudited) 566,335 4.04 Vested (unaudited) (55,135 ) 11.96 Forfeited (unaudited) (215,974 ) 4.33 Outstanding at June 30, 2018 (unaudited) 490,398 5.78
Summary of Stock Options	Summary of stock option information is as follows: OPTIONS OUTSTANDING WEIGHTED- AVERAGE EXERCISE PRICE WEIGHTED- AVERAGE REMAINING CONTRACT TERM (in years) AGGREGATE INTRINSIC VALUE (in thousands) Outstanding at December 31, 2017 4,094,532 $ 10.96 7.21 $ 2,771 Granted (unaudited) 1,198,020 $ 3.98 Exercised (unaudited) (1,598 ) $ 1.15 Expired (unaudited) (188,493 ) $ 13.76 Forfeited (unaudited) (125,619 ) $ 8.68 Outstanding at June 30, 2018 (unaudited) 4,976,842 $ 9.23 7.42 $ 3,940 Exercisable as of June 30, 2018 (unaudited) 2,774,538 $ 10.74 6.25 $ 3,281
Schedule of Stock-Based Compensation Expense Recognized	Total stock-based compensation expense recognized in our condensed consolidated statements of operations and comprehensive income (loss) is as follows (in thousands): Three Months Ended June 30, Six Months Ended June 30, 2018 2017 2018 2017 (unaudited) (unaudited) (unaudited) (unaudited) Employee: Research and development $ 688 $ 904 $ 1,888 $ 1,837 General and administrative 808 1,242 2,333 2,522 Non-Employee: Research and development 14 34 23 57 General and administrative 1 25 5 36 Total stock-based compensation expense $ 1,511 $ 2,205 $ 4,249 $ 4,452
Schedule of Fair Value of Stock Options Granted to Employees	The fair values of stock options granted to employees were calculated using the following assumptions: Three Months Ended June 30, Six Months Ended June 30, 2018 2017 2018 2017 (unaudited) (unaudited) (unaudited) (unaudited) Weighted-average estimated fair value $2.75 $4.86 $2.69 $3.93 Risk-free interest rate 2.8% - 2.9% 1.9% - 2.0% 2.3% - 2.9% 1.9% - 2.1% Expected term of options (in years) 6.08 6.08 5.50 - 6.08 5.50 - 6.08 Expected stock price volatility 78% 80% 78% 80% - 82% Expected dividend yield — — — —
Schedule of Share-based Compensation, Shares Authorized under Stock Option Plans, by Exercise Price Range	Eligible Option Exercise Price Ranges Exchange Ratio (Surrendered Eligible Options: New Options)* $5.00-$14.99 1.50 to 1 $15.00-$29.99 1.75 to 1 $30.00-And Up 2.00 to 1 * Rounded up to the nearest share

Description of the Business - N

Description of the Business - Narrative (Details)	6 Months Ended
	Jun. 30, 2018platform
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of discovery platforms (in platforms)	2

Summary of Significant Accoun28

Summary of Significant Accounting Policies (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017	Jun. 30, 2017
Accounting Policies [Abstract]
Restricted cash	$ 0	$ 6,000	$ 6,000

Net Loss Per Share - Common Sto

Net Loss Per Share - Common Stock Issuable Upon the Conversion or Exercise of Dilutive Securities Excluded from Diluted Net Loss Per Share Attributable to Common Stockholders (Details) - shares	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (in shares)	5,467,240	4,439,925
Outstanding options to purchase common stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (in shares)	4,976,842	4,142,900
Unvested restricted stock units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (in shares)	490,398	297,025

Cash Equivalents and Short-Te30

Cash Equivalents and Short-Term Investments (Details) - USD ($)	6 Months Ended	12 Months Ended
	Jun. 30, 2018	Dec. 31, 2017	Jun. 30, 2017
Gain (Loss) on Investments [Line Items]
Money market funds, Amortized Cost	$ 73,430,000	$ 72,454,000	$ 35,311,000
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(35,000)	(49,000)
Amortized Cost	118,151,000	139,204,000
Fair Value	118,116,000	139,155,000
Cash equivalents	71,321,000	70,502,000
Short-term investments	46,795,000	68,653,000
Total	118,116,000	139,155,000
Money market funds
Gain (Loss) on Investments [Line Items]
Money market funds, Amortized Cost	71,321,000	70,502,000
Money market funds, Fair Value	71,321,000	70,502,000
U.S. Treasury securities
Gain (Loss) on Investments [Line Items]
Available-for-sale Debt Securities, Amortized Cost	46,830,000	68,702,000
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(35,000)	(49,000)
Fair Value	46,795,000	68,653,000
Realized gain (losses) on U.S. Treasury securities	$ 0	$ 0

Fair Value of Financial Instr31

Fair Value of Financial Instruments - Financial Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) - Fair Value, Measurements, Recurring - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total	$ 118,116	$ 139,155
Money market funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Money market funds	71,321	70,502
U.S. Treasury securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale securities, fair value	46,795	68,653
LEVEL 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total	118,116	139,155
LEVEL 1 | Money market funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Money market funds	71,321	70,502
LEVEL 1 | U.S. Treasury securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale securities, fair value	46,795	68,653
LEVEL 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total	0	0
LEVEL 2 | Money market funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Money market funds	0	0
LEVEL 2 | U.S. Treasury securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale securities, fair value	0	0
LEVEL 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total	0	0
LEVEL 3 | Money market funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Money market funds	0	0
LEVEL 3 | U.S. Treasury securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale securities, fair value	$ 0	$ 0

Inventory (Details)

Inventory (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Inventory Disclosure [Abstract]
Raw materials	$ 16	$ 0
Work in process	757	541
Finished goods	127	143
Total inventory	$ 900	$ 684

Accrued Liabilities (Details)

Accrued Liabilities (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Payables and Accruals [Abstract]
Research and development services	$ 2,888	$ 3,352
Employee compensation	1,794	2,777
Other	63	57
Total accrued liabilities	$ 4,745	$ 6,186

Commitments and Contingencies -

Commitments and Contingencies - Narrative (Details)	Jan. 01, 2017USD ($)ft²	May 31, 2017USD ($)ft²	Jan. 31, 2017USD ($)	Oct. 31, 2016USD ($)	Dec. 31, 2015USD ($)	Jul. 31, 2015USD ($)	Jan. 31, 2015USD ($)ft²	Jun. 30, 2018USD ($)
Other Commitments [Line Items]
Square feet of office and laboratory space (in square feet) | ft²	20,133						9,640
Operating lease, contract term (in years)	5 years
Operating lease, optional lease extension period (in years)	3 years						5 years
Operating lease, annual base rent	$ 1,100,000
Operating lease, annual increase in base rate (as a percent)	2.50%
Security deposit provided during the period			$ 200,000
Sublease area (in square feet) | ft²		5,048
Sub-lease term (in years)		3 years
Sublease minimum rental expense		$ 273,000
Sublease annual base rent increase (as a percent)		2.50%
Funds drawn on letter of credit								$ 0
Collaborative revenue | ZVex Product | Maximum
Other Commitments [Line Items]
Potential future milestone payments								7,700,000
Collaborative revenue | NanoPass Technologies LTD | Intradermal Delivery Device
Other Commitments [Line Items]
Collaborative arrangement, license fee					$ 500,000	$ 600,000
Collaborative arrangement, non-refundable payment				$ 150,000
Collaborative revenue | NanoPass Technologies LTD | Intradermal Delivery Device | Maximum
Other Commitments [Line Items]
Potential future milestone payments				$ 8,800,000
Collaborative revenue | Infectious Disease Research Institute | GLA/SLA First Exclusive Product | Maximum
Other Commitments [Line Items]
Potential future milestone payments								2,300,000
Collaborative revenue | Infectious Disease Research Institute | GLA/SLA Subsequent Exclusive Products | Maximum
Other Commitments [Line Items]
Potential future milestone payments								1,300,000
Collaborative revenue | Infectious Disease Research Institute | GLA/SLA First Non-Exclusive Product | Maximum
Other Commitments [Line Items]
Potential future milestone payments								1,300,000
Collaborative revenue | Infectious Disease Research Institute | GLA/SLA Subsequent Non-Exclusive Products | Maximum
Other Commitments [Line Items]
Potential future milestone payments								$ 625,000
Standby Letter of Credit
Other Commitments [Line Items]
Letter of credit provided as security deposit							$ 121,000

License and Collaboration Agr35

License and Collaboration Agreements - Narrative (Details)	1 Months Ended				3 Months Ended		6 Months Ended		12 Months Ended
	Oct. 31, 2016USD ($)payment	Dec. 31, 2015USD ($)	Nov. 30, 2015USD ($)	Aug. 31, 2014	Jun. 30, 2018USD ($)	Jun. 30, 2017USD ($)	Jun. 30, 2018USD ($)	Jun. 30, 2017USD ($)	Dec. 31, 2014USD ($)	Dec. 31, 2010USD ($)	Dec. 31, 2009USD ($)	Dec. 31, 2017USD ($)	Oct. 31, 2010license_agreement
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Research and development					$ 11,000,000	$ 10,863,000	$ 21,311,000	$ 24,901,000
Herpes Simplex Virus Immune Therapy | Sanofi Pasteur | Collaborative revenue
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Milestone revenue recognized					311,000	681,000	807,000	5,900,000
Collaborative Arrangement, Product | GLAAS Discovery Platform | Sanofi
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Upfront payment received									$ 3,500,000
Milestone revenue recognized					0	0	0	0
Milestone receivables					160,000,000		160,000,000
Milestone agreement, notice period required for agreement termination (in months)				6 months
Collaborative Arrangement, Product | GLA | MedImmune LLC
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Upfront payment received										$ 4,500,000
Milestone revenue recognized					0	0	0	0
Number of license agreements | license_agreement													2
Collaborative Arrangement, Product | GLA | MedImmune LLC | Minimum
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Milestone receivables					62,900,000		62,900,000
Collaborative Arrangement, Product | GLA | MedImmune LLC | Maximum
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Milestone receivables					72,500,000		72,500,000
Collaborative Arrangement, Product | Herpes Simplex Virus Immune Therapy | Sanofi Pasteur
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Unbilled receivable					406,000		406,000					$ 605,000
Collaborative revenue | TheraVectys SA
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Research and development					0	0	0	0
Collaborative revenue | TheraVectys SA | Maximum
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Potential future milestone payments	$ 5,800,000
Number of milestone payments waived (in payments) | payment	2
Collaborative revenue | GLAAS Discovery Platform | Infectious Disease Research Institute
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Research and development			$ 250,000
Collaborative revenue | GLA | Infectious Disease Research Institute
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Milestone revenue recognized					0	0	0	0
Collaborative revenue | First GLAAS Discovery Platform Product | Infectious Disease Research Institute
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Potential future milestone payments					250,000		250,000
Collaborative revenue | Subsequent GLAAS Discovery Platform Products | Infectious Disease Research Institute
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Potential future milestone payments					125,000		125,000
Collaborative revenue | GLA/SLA Product | Infectious Disease Research Institute
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Research and development		$ 2,300,000
Collaborative revenue | GLA/SLA First Exclusive Product | Infectious Disease Research Institute | Maximum
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Potential future milestone payments					2,300,000		2,300,000
Collaborative revenue | GLA/SLA Subsequent Exclusive Products | Infectious Disease Research Institute | Maximum
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Potential future milestone payments					1,300,000		1,300,000
Collaborative revenue | GLA/SLA First Non-Exclusive Product | Infectious Disease Research Institute | Maximum
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Potential future milestone payments					1,300,000		1,300,000
Collaborative revenue | GLA/SLA Subsequent Non-Exclusive Products | Infectious Disease Research Institute | Maximum
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Potential future milestone payments					625,000		625,000
Collaborative revenue | Dendritic Cell-targeted Theraputic and Prophylactic Immunization Strategies | CalTech
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Milestone revenue recognized					0	$ 100,000	0	$ 100,000
Annual minimum royalty payments											$ 25,000
Collaborative revenue | Dendritic Cell-targeted Theraputic and Prophylactic Immunization Strategies | CalTech | Common Stock
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Value of common stock issued for license											$ 25,000
Collaborative revenue | Dendritic Cell-targeted Theraputic and Prophylactic Immunization Strategies | CalTech | Maximum
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Potential future milestone payments					$ 1,500,000		$ 1,500,000

Stockholders' Equity - Narrativ

Stockholders' Equity - Narrative (Details)	Jul. 17, 2018employee$ / sharesshares	Jun. 18, 2018$ / shares	Jun. 17, 2018$ / shares	Jan. 01, 2018shares	Jan. 31, 2018shares	Jul. 31, 2017USD ($)	Jun. 30, 2018USD ($)shares	Jun. 30, 2017USD ($)	Jun. 30, 2018USD ($)$ / sharesshares	Jun. 30, 2017USD ($)	Dec. 31, 2017shares
Equity [Abstract]
Preferred shares issued (in shares)							0		0		0
Preferred shares outstanding (in shares)							0		0		0
Common shares outstanding (in shares)							48,164,828		48,164,828		48,068,650
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Value of shares authorized under purchase agreement | $						$ 50,000,000
Commission, percent of gross sales proceeds						3.00%
Share-based compensation expense | $							$ 1,511,000	$ 2,205,000	$ 4,249,000	$ 4,452,000
Options forfeited (in shares)									125,619
Options granted (in shares)									1,198,020
Options granted (in dollars per share) | $ / shares									$ 3.98
Subsequent Event
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of employees who elected to exchange options | employee	31
Shares repurchased during period	1,590,083
Percent of eligible shares exercised	65.00%
Options granted during period	962,099
Option exercise price (in dollars per share) | $ / shares	$ 4.40
Unvested restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted during period					198,835				566,335
Award vesting period					3 years
Number of instruments expired									183,750
Share-based compensation expense | $							508,000
Unvested restricted stock units | Tranche one
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting rate									33.33%
Unvested restricted stock units | Tranche two
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting rate									33.33%
Unvested restricted stock units | Tranche three
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting rate									33.33%
PSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted during period					367,500
Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized stock based compensation expense | $							$ 9,500,000		$ 9,500,000
Weighted average recognition period for stock-based compensation expense (in years)									2 years 10 days
Intrinsic value of stock options exercised | $									$ 4,000	$ 544,000
2014 Omnibus Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Annual additional shares authorized									4.00%
Increase in authorized shares (in shares)				1,922,746
Common stock authorized (in shares)							5,837,813		5,837,813
2014 Employee Stock Purchase Plan | Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Annual additional shares authorized									1.00%
Increase in authorized shares (in shares)									200,000
Common stock authorized (in shares)							435,565		435,565
Stock Option Exchange Program
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period		7 years
Exercise price range, lower range limit | $ / shares		$ 4.10	$ 5
Stock Option Exchange Program | Subsequent Event
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options returned and available for future issuance	627,984
Stock Option Exchange Program | Exercise Range 1
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise price range, lower range limit | $ / shares		5
Exercise price range, high range limit | $ / shares		$ 14.99
Exchange ratio		1.5
Stock Option Exchange Program | Exercise Range 2
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise price range, lower range limit | $ / shares		$ 15
Exercise price range, high range limit | $ / shares		$ 29.99
Exchange ratio		1.75
Stock Option Exchange Program | Exercise Range 3
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise price range, lower range limit | $ / shares		$ 30
Exchange ratio		2
Stock Option Exchange Program | Tranche one
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period		2 years
Stock Option Exchange Program | Tranche two
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period		3 years

Stockholders' Equity - Schedule

Stockholders' Equity - Schedule of Shares of Common Stock Reserved for Future Issuance (Details) - shares	Jun. 30, 2018	Dec. 31, 2017
Class of Stock [Line Items]
Common stock reserved for future issuance (in shares)	7,538,481	5,711,913
Employee Stock Purchase Plan
Class of Stock [Line Items]
Common stock reserved for future issuance (in shares)	435,565	475,010
Options
Class of Stock [Line Items]
Common stock reserved for future issuance (in shares)	4,976,842	4,094,532
Restricted Stock Units
Class of Stock [Line Items]
Common stock reserved for future issuance (in shares)	490,398	195,172
Future Stock Grants
Class of Stock [Line Items]
Common stock reserved for future issuance (in shares)	1,635,676	947,199

Stockholders' Equity - Schedu38

Stockholders' Equity - Schedule of Restricted Stock Units Activity (Details) - Restricted Stock Units - $ / shares	1 Months Ended	6 Months Ended
	Jan. 31, 2018	Jun. 30, 2018
SHARES
Outstanding, beginning balance (in shares)	195,172	195,172
Granted (unaudited) (in shares)	198,835	566,335
Vested (unaudited) (in shares)		(55,135)
Forfeited (unaudited) (in shares)		(215,974)
Outstanding, ending balance (unaudited) (in shares)		490,398
WEIGHTED AVERAGE GRANT DATE FAIR VALUE (per share)
Outstanding, beginning balance (in dollars per share)	$ 10.99	$ 10.99
Granted (unaudited) (in dollars per share)		4.04
Vested (unaudited) (in dollars per share)		11.96
Forfeited (unaudited) (in dollars per share)		4.33
Outstanding, ending balance (unaudited) (in dollars per share)		$ 5.78

Stockholders' Equity - Summary

Stockholders' Equity - Summary of Stock Options (Details) - USD ($) $ / shares in Units, $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2018	Dec. 31, 2017
OPTIONS OUTSTANDING
Options outstanding, beginning balance (in shares)	4,094,532
Options granted (unaudited) (in shares)	1,198,020
Options exercised (unaudited) (in shares)	(1,598)
Options expired (unaudited) (in shares)	(188,493)
Options forfeited (unaudited) (in shares)	(125,619)
Options outstanding, ending balance (unaudited) (in shares)	4,976,842	4,094,532
Exercisable options as of June 30, 2018 (unaudited) (in shares)	2,774,538
WEIGHTED- AVERAGE EXERCISE PRICE
Options outstanding, beginning balance (in dollars per share)	$ 10.96
Options granted (unaudited) (in dollars per share)	3.98
Options exercised (unaudited) (in dollars per share)	1.15
Options expired (unaudited) (in dollars per share)	13.76
Options forfeited (unaudited) (in dollars per share)	8.68
Options outstanding, ending balance (unaudited) (in dollars per share)	9.23	$ 10.96
Exercisable options as of June 30, 2018 (unaudited) (in dollars per share)	$ 10.74
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Weighted average remaining contract term for outstanding options (in years)	7 years 5 months 1 day	7 years 2 months 15 days
Weighted average remaining contract term for exercisable options as of June 30, 2018 (unaudited) (in years)	6 years 3 months
Aggregate intrinsic value	$ 3,940	$ 2,771
Aggregate intrinsic value of exercisable options as of June 30, 2018 (unaudited)	$ 3,281

Stockholders' Equity - Schedu40

Stockholders' Equity - Schedule of Stock-Based Compensation Expense Recognized (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Share-based compensation expense	$ 1,511	$ 2,205	$ 4,249	$ 4,452
Employee | Research and development
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Share-based compensation expense	688	904	1,888	1,837
Employee | General and administrative
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Share-based compensation expense	808	1,242	2,333	2,522
Non-Employee | Research and development
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Share-based compensation expense	14	34	23	57
Non-Employee | General and administrative
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Share-based compensation expense	$ 1	$ 25	$ 5	$ 36

Stockholders' Equity - Schedu41

Stockholders' Equity - Schedule of Fair Value of Stock Options Granted to Employees (Details) - Options - $ / shares	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted-average estimated fair value (in dollars per share)	$ 2.75	$ 4.86	$ 2.69	$ 3.93
Expected term of options (in years)	6 years 29 days	6 years 29 days
Expected stock price volatility		80.00%
Expected dividend yield	0.00%	0.00%	0.00%	0.00%
Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rate	2.80%	1.90%	2.30%	1.90%
Expected term of options (in years)			5 years 6 months	5 years 6 months
Expected stock price volatility				80.00%
Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rate	2.90%	2.00%	2.90%	2.10%
Expected term of options (in years)			6 years 29 days	6 years 29 days
Expected stock price volatility				82.00%

Income Taxes (Details)

Income Taxes (Details) - USD ($)	Dec. 22, 2017	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Decrease in deferred tax asset due to Tax Act	$ 30,500,000
Tax rate reconciliation, tax cuts and jobs act, amount		$ 0

Legal Proceedings (Details)

Legal Proceedings (Details)	Oct. 17, 2016USD ($)claim	Feb. 28, 2018USD ($)	Nov. 30, 2017USD ($)	Dec. 31, 2016USD ($)
Loss Contingencies [Line Items]
Proceeds from issuance of common stock			$ 86,600,000
Escrow disbursements made during the period		$ 750,000
TheraVectys SA
Loss Contingencies [Line Items]
Escrow disbursements made during the period		$ 5,250,000
Collaborative revenue | TheraVectys SA
Loss Contingencies [Line Items]
Settlement agreement allocated to license agreement	$ 1,400,000			$ 1,400,000
TheraVectys SA v. Immune Design Corp.
Loss Contingencies [Line Items]
Number of complaints | claim	4
Payments for underwriting expense			$ 1,250,000
TheraVectys SA v. Immune Design Corp. | Settled Litigation
Loss Contingencies [Line Items]
Settlement agreement, escrow deposit	$ 6,000,000
Settlement agreement, contingent escrow payment	1,250,000
Settlement agreement, contingent escrow deposit, capital funding threshold	$ 25,000,000
Release of escrow deposit due to granting of sublicense (as a percent)	50.00%
Release of escrow deposit due to final resolution of EPO proceedings (as a percent)	50.00%
Litigation settlement and license agreement fees	$ 7,250,000
Litigation settlement	$ 5,850,000
Settlement agreement for dismissal of litigation				$ 5,850,000