Fresh Tracks Therapeutics (FRTX) 10-Q 7 Aug 18 2018 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2018	Jul. 31, 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	VICL
Entity Registrant Name	VICAL INC
Entity Central Index Key	819,050
Current Fiscal Year End Date	--12-31
Entity Filer Category	Smaller Reporting Company
Entity Common Stock, Shares Outstanding		21,815,979

Balance Sheets

Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 10,071	$ 24,841
Marketable securities, available-for-sale	41,832	35,658
Restricted cash	192	192
Deferred contract costs		10,502
Receivables and other assets	1,610	5,124
Total current assets	53,705	76,317
Long-term investments	2,237	2,209
Property and equipment, net	165	606
Intangible assets, net		703
Other assets	659	659
Total assets	56,766	80,494
Current liabilities:
Accounts payable and accrued expenses	3,161	5,217
Deferred revenue	20	11,700
Total current liabilities	3,181	16,917
Stockholders' equity:
Preferred stock, $0.01 par value, 5,000 shares authorized, none issued and outstanding	0	0
Common stock, $0.01 par value, 50,000 shares authorized, 21,815 and 21,802 shares issued and outstanding at June 30, 2018 and December 31, 2017, respectively	218	218
Additional paid-in capital	490,185	489,975
Accumulated deficit	(436,948)	(426,738)
Accumulated other comprehensive income	130	122
Total stockholders' equity	53,585	63,577
Total liabilities and stockholders' equity	$ 56,766	$ 80,494

Balance Sheets (Parenthetical)

Balance Sheets (Parenthetical) - $ / shares	Jun. 30, 2018	Dec. 31, 2017
Statement Of Financial Position [Abstract]
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, shares authorized	5,000,000	5,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	50,000,000	50,000,000
Common stock, shares issued	21,815,000	21,802,000
Common stock, shares outstanding	21,815,000	21,802,000

Statements of Operations

Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Revenues:
Contract revenue	$ 725	$ 3,369	$ 1,431	$ 6,270
License and royalty revenue	10	52	20	356
Total revenues	735	3,421	1,451	6,626
Operating expenses:
Research and development	3,602	3,639	7,266	6,939
Manufacturing and production		1,602	1,436	2,911
General and administrative	2,261	1,591	4,378	3,100
Total operating expenses	5,863	6,832	13,080	12,950
Loss from operations	(5,128)	(3,411)	(11,629)	(6,324)
Other income:
Investment and other income, net	260	91	491	180
Net loss	$ (4,868)	$ (3,320)	$ (11,138)	$ (6,144)
Basic and diluted net loss per share	$ (0.22)	$ (0.30)	$ (0.51)	$ (0.55)
Weighted average shares used in computing basic and diluted net loss per share	21,837	11,139	21,834	11,121

Statements of Comprehensive Los

Statements of Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Statement Of Income And Comprehensive Income [Abstract]
Net loss	$ (4,868)	$ (3,320)	$ (11,138)	$ (6,144)
Unrealized gain on available-for-sale and long-term marketable securities:
Unrealized gain arising during holding period, net of tax benefit of $6 and $17 for three months ended June 30, 2018 and 2017, respectively, and $6 and $38 for six months ended June 30, 2018 and 2017, respectively	73	32	8	68
Other comprehensive gain	73	32	8	68
Total comprehensive loss	$ (4,795)	$ (3,288)	$ (11,130)	$ (6,076)

Statements of Comprehensive Lo6

Statements of Comprehensive Loss (Parenthetical) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Jun. 30, 2018	Jun. 30, 2017
Statement Of Income And Comprehensive Income [Abstract]
Unrealized (loss) gain arising during holding period, tax benefit	$ 6	$ 17	$ 6	$ 38

Statements of Cash Flows

Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Cash flows from operating activities:
Net loss	$ (11,138)	$ (6,144)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	49	526
Write-off of abandoned patents	673	0
Compensation expense related to stock options and awards	209	428
Changes in operating assets and liabilities:
Deferred contract costs	0	(2,934)
Receivables and other assets	3,882	313
Accounts payable and accrued expenses	(2,056)	(124)
Deferred revenue	(249)	4,185
Deferred rent	0	(223)
Net cash used in operating activities	(8,630)	(3,973)
Cash flows from investing activities:
Maturities of marketable securities	14,719	12,407
Purchases of marketable securities	(20,843)	(9,180)
Purchases of property and equipment	(16)	(19)
Net cash (used in) provided by investing activities	(6,140)	3,208
Cash flows from financing activities:
Net proceeds from issuance of common stock	1	312
Payment of withholding taxes for net settlement of restricted stock units	(1)	(2)
Net cash provided by financing activities	0	310
Net decrease in cash, cash equivalents and restricted cash	(14,770)	(455)
Cash, cash equivalents and restricted cash at beginning of period	25,033	8,380
Cash, cash equivalents and restricted cash at end of period	$ 10,263	$ 7,925

Basis of Presentation

Basis of Presentation	6 Months Ended
	Jun. 30, 2018
Accounting Policies [Abstract]
Basis of Presentation	1. BASIS OF PRESENTATION Vical Incorporated, or the Company, a Delaware corporation, was incorporated in April 1987 and has devoted substantially all of its resources since that time to its research and development programs. The Company develops biopharmaceutical products for the prevention and treatment of chronic or life-threatening infectious diseases, including a candidate for treating chronic hepatitis B in preclinical development and an antifungal candidate in clinical development. All of the Company’s potential products are in research and development phases. No revenues have been generated from the sale of any such products, nor are any such revenues expected for at least the next several years. The Company earns revenue from research and development agreements with pharmaceutical collaborators and from contract manufacturing agreements. The Company’s product candidates will require significant additional research and development efforts, including extensive preclinical and clinical testing. All product candidates that advance to clinical testing will require regulatory approval prior to commercial use, and will require significant costs for commercialization. There can be no assurance that the Company’s research and development efforts, or those of its collaborators, will be successful. The Company expects to continue to incur substantial losses and not generate positive cash flows from operations for at least the next several years. No assurance can be given that the Company can generate sufficient product revenue to become profitable or generate positive cash flows from operations. The unaudited financial statements at June 30, 2018, and for the three and six months ended June 30, 2018 and 2017, have been prepared in accordance with the rules and regulations of the Securities and Exchange Commission, or SEC, and with accounting principles generally accepted in the United States applicable to interim financial statements. These unaudited financial statements have been prepared on the same basis as the audited financial statements included in the Company’s Annual Report on Form 10-K and include all adjustments, consisting of only normal recurring accruals, which in the opinion of management are necessary to present fairly the Company’s financial position as of the interim date and results of operations for the interim periods presented. Interim results are not necessarily indicative of results expected for a full year or future periods. The preparation of financial statements requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosures of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ materially from those estimates. These unaudited financial statements should be read in conjunction with the Company’s audited financial statements for the year ended December 31, 2017, included in its Annual Report on Form 10-K filed with the SEC. Cash, Cash Equivalents and Marketable Securities Cash and cash equivalents consist of cash and highly liquid securities with original maturities at the date of acquisition of ninety days or less and can be liquidated without prior notice or penalty. Investments with an original maturity of more than ninety days are considered marketable securities and have been classified by management as available-for-sale. These investments are classified as current assets, even though the stated maturity date may be one year or more beyond the current balance sheet date which reflects management’s intention to use the proceeds from sales of these securities to fund its operations, as necessary. Such investments are carried at fair value, with unrealized gains and losses included as a separate component of stockholders’ equity. Realized gains and losses from the sale of available-for-sale securities or the amounts, net of tax, reclassified out of accumulated other comprehensive income (loss), if any, are determined on a specific identification basis. Restricted Cash The Company was required to maintain a letter of credit securing an amount equal to twelve months of the then current monthly installment of base rent for the original term of the lease for its facilities, which ended on August 31, 2017. In July 2016, the term of the lease was extended for 16 months through December 2018. During the extended term, the Company is required to maintain a letter of credit securing an amount equal to $0.2 million. Revenue Recognition We recognize revenue when control of our products and services is transferred to our customers in an amount that reflects the consideration we expect to receive from our customers in exchange for those products and services. This process involves identifying the contract with a customer, determining the performance obligations in the contract, determining the contract price, allocating the contract price to the distinct performance obligations in the contract, and recognizing revenue when the performance obligations have been satisfied. A performance obligation is considered distinct from other obligations in a contract when it provides a benefit to the customer either on its own or together with other resources that are readily available to the customer and is separately identified in the contract. We consider a performance obligation satisfied once we have transferred control of a good or service to the customer, meaning the customer has the ability to use and obtain the benefit of the good or service. We recognize revenue for satisfied performance obligations only when we determine there are no uncertainties regarding payment terms or transfer of control. Research and Development Costs Research and development costs are expensed as incurred. Research and development costs include salaries and personnel-related costs, supplies and materials, outside services, costs of conducting preclinical and clinical trials, facilities costs and amortization of intangible assets. The Company accounts for its clinical trial costs by estimating the total cost to treat a patient in each clinical trial, and accruing this total cost for the patient over the estimated treatment period, which corresponds with the period over which the services are performed, beginning when the patient enrolls in the clinical trial. This estimated cost includes payments to the site conducting the trial, and patient-related lab and other costs related to the conduct of the trial. Cost per patient varies based on the type of clinical trial, the site of the clinical trial, the method of administration of the treatment, and the number of treatments that a patient receives. Treatment periods vary depending on the clinical trial. The Company makes revisions to the clinical trial cost estimates in the current period, as clinical trials progress. Manufacturing and Production Costs Manufacturing and production costs include expenses related to manufacturing contracts and expenses for the production of plasmid DNA for use in the Company’s research and development efforts. Production expenses related to the Company’s research and development efforts are expensed as incurred. Net Loss Per Share Basic and diluted net loss per share has been computed using the weighted-average number of shares of common stock outstanding during the period. The weighted average number of shares used to compute diluted loss per share excludes any assumed exercise of stock options and warrants and any assumed issuance of common stock under restricted stock units (RSUs) as the effect would be antidilutive. Common stock equivalents of 7.2 million for the three and six months ended June 30, 2018 were excluded from the calculation because of their antidilutive effect. There were no common stock equivalents for the three and six months ended June 30, 2017. Stock-Based Compensation The Company records its compensation expense associated with stock options and other forms of equity compensation based on their fair value at the date of grant using the Black-Scholes-Merton option pricing model. Stock-based compensation includes amortization related to stock option awards based on the estimated grant date fair value. Stock-based compensation expense related to stock options is recognized ratably over the vesting period of the option. In addition, the Company records expense related to RSUs granted based on the fair value of those awards on the grant date. The fair value related to the RSUs is amortized to expense over the vesting term of those awards. Forfeitures of stock options and RSUs are recognized as they occur. Stock-based compensation expense for a stock-based award with a performance condition is recognized when the achievement of such performance condition is determined to be probable. If the outcome of such performance condition is not determined to be probable or is not met, no compensation expense is recognized and any previously recognized compensation expense is reversed. Recent Accounting Pronouncements In May 2014, the Financial Accounting Standards Board (the “FASB”) issued ASU No. 2014-09, “Revenue from Contracts with Customers” which outlines a single comprehensive model for entities to use in accounting for revenue arising from contracts with customers. The Company adopted the new standard effective January 1, 2018 using the modified retrospective method applied to contracts not completed as of December 31, 2017. As it relates to process validation lots and stock piling lots completed but not delivered as of December 31, 2017 at the request of a customer, the Company concluded that, under ASC 606, the criteria for transfer of control were met prior to January 1, 2018 and as a result, Income Statement As Reported Balances Without Adoption of ASC 606 Effect of Change Increase/(Decrease) Revenues Contract revenue $ 1,431 $ 1,431 $ - Operating expenses Manufacturing and production 1,436 1,436 - Net loss (11,138 ) (11,138 ) - Balance Sheet As Reported Balances Without Adoption of ASC 606 Effect of Change Increase/(Decrease) Assets Deferred contract costs $ — $ 10,502 $ (10,502 ) Liabilities Deferred revenue 20 11,450 (11,430 ) Equity Accumulated deficit (436,948 ) (437,876 ) 928 In February 2016, the FASB issued ASU No. 2016-02, “Leases (Topic 842).” The new standard requires a lessee to record on the balance sheet the assets and liabilities for the rights and obligations created by leases with lease terms of more than 12 months and will require both lessees and lessors to disclose certain key information about lease transactions. The standard will be effective for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years. The Company is evaluating the effect that the adoption of the new guidance will have on its financial statements and related disclosures.

Stock-Based Compensation

Stock-Based Compensation	6 Months Ended
	Jun. 30, 2018
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock-Based Compensation	2. STOCK-BASED COMPENSATION Total stock-based compensation expense was allocated to research and development, manufacturing and production and general and administrative expense as follows (in thousands): Three Months Ended Six Months Ended June 30, June 30, 2018 2017 2018 2017 Research and development $ 48 $ 56 $ 76 $ 123 Manufacturing and production — 37 (68 ) 65 General and administrative 114 104 201 240 Total stock-based compensation expense $ 162 $ 197 $ 209 $ 428 During the six months ended June 30, 2018 and June 30, 2017, the Company granted stock-based awards with a total estimated value of $0.4 million and $0.7 million, respectively. At June 30, 2018, total unrecognized estimated compensation expense related to unvested stock-based awards granted prior to that date was $0.5 million, which is expected to be recognized over a weighted-average period of 1.4 years. Stock-based awards granted during the six months ended June 30, 2018 and 2017, were equal to 2.5% and 5.1%, respectively, of the outstanding shares of common stock at the end of the applicable period.

Marketable Securities, Availabl

Marketable Securities, Available for Sale	6 Months Ended
	Jun. 30, 2018
Investments Debt And Equity Securities [Abstract]
Marketable Securities, Available for Sale	3. MARKETABLE SECURITIES, AVAILABLE FOR SALE The following is a summary of available-for-sale marketable securities (in thousands): June 30, 2018 Amortized Cost Unrealized Gain Unrealized Loss Market Value U.S. treasuries $ 41,875 $ — $ 43 $ 41,832 $ 41,875 $ — $ 43 $ 41,832 December 31, 2017 Amortized Cost Unrealized Gain Unrealized Loss Market Value U.S. treasuries $ 34,462 $ — $ 29 $ 34,433 Certificates of deposit 1,225 — — 1,225 $ 35,687 $ — $ 29 $ 35,658 At June 30, 2018, none of these securities were scheduled to mature outside of one year. The Company did not realize any gains or losses on sales of available-for-sale securities for the six months ended June 30, 2018. As of June 30, 2018, none of the securities had been in a continuous material unrealized loss position longer than one year.

Other Balance Sheet Accounts

Other Balance Sheet Accounts	6 Months Ended
	Jun. 30, 2018
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Other Balance Sheet Accounts	4. OTHER BALANCE SHEET ACCOUNTS Accounts payable and accrued expenses consisted of the following (in thousands): June 30, December 31, 2018 2017 Employee compensation $ 1,315 $ 2,654 Clinical trial accruals 1,315 1,017 Accounts payable 357 1,213 Employee termination benefits accrual 2 — Other accrued liabilities 172 333 Total accounts payable and accrued expenses $ 3,161 $ 5,217

Long-Term Investments

Long-Term Investments	6 Months Ended
	Jun. 30, 2018
Investments All Other Investments [Abstract]
Long-Term Investments	5. LONG-TERM INVESTMENTS As of June 30, 2018, the Company held an auction rate security with a par value of $2.5 million. This auction rate security has not experienced a successful auction since the liquidity issues experienced in the global credit and capital markets in 2008. As a result, the security is classified as a long-term investment as it is scheduled to mature in 2038. The security was rated BBB by Standard and Poor’s as of June 30, 2018. The security continues to pay interest according to its stated terms. The valuation of the Company’s auction rate security is subject to uncertainties that are difficult to predict. The fair value of the security is estimated utilizing a discounted cash flow analysis. The key drivers of the valuation model include the expected term, collateral underlying the security investment, the creditworthiness of the counterparty, the timing of expected future cash flows, discount rates, liquidity and the expected holding period. The security was also compared, when possible, to other observable market data for securities with similar characteristics. As of June 30, 2018, the inputs used in the Company’s discounted cash flow analysis assumed an interest rate of 5.73%, an estimated redemption period of five years and a discount rate of 1.00%. Based on the valuation of the security, the Company has recognized cumulative losses of $0.4 million as of June 30, 2018, none of which were realized during the six months ended June 30, 2018. The losses when recognized are included in investment and other income. The market value of the security has partially recovered. Included in other comprehensive income are unrealized gains of $22,000 and $74,000 for the six months ended June 30, 2018 and 2017, respectively. As of June 30, 2018, the Company had recorded cumulative unrealized gains of $0.4 million. The resulting carrying value of the auction rate security at June 30, 2018, was $2.2 million. Any future decline in market value may result in additional losses being recognized.

Fair Value Measurements

Fair Value Measurements	6 Months Ended
	Jun. 30, 2018
Fair Value Disclosures [Abstract]
Fair Value Measurements	6. FAIR VALUE MEASUREMENTS The Company measures fair value as an exit price, representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. As such, fair value is a market-based measurement that should be determined based on assumptions that market participants would use in pricing an asset or liability. Fair value measurements are based on a three-tier fair value hierarchy, which prioritizes the inputs used in measuring fair value as follows: • Level 1: Observable inputs such as quoted prices in active markets; • Level 2: Inputs, other than the quoted prices in active markets, that are observable either directly or indirectly; and • Level 3: Unobservable inputs in which there is little or no market data, which require the reporting entity to develop its own assumptions. Cash equivalents, marketable securities and long-term investments measured at fair value are classified in the table below in one of the three categories described above (in thousands): Fair Value Measurements June 30, 2018 Level 1 Level 2 Level 3 Total Money market funds 6,733 — — 6,733 U.S. treasuries 41,832 — — 41,832 Auction rate securities — — 2,237 2,237 $ 48,565 $ — $ 2,237 $ 50,802 Fair Value Measurements December 31, 2017 Level 1 Level 2 Level 3 Total Certificates of deposit $ 1,225 $ — $ — $ 1,225 Money market funds 21,760 — — 21,760 U.S. treasuries 34,433 — — 34,433 Auction rate securities — — 2,209 2,209 $ 57,418 $ — $ 2,209 $ 59,627 The Company’s investments in U.S. treasury securities, certificates of deposit and money market funds are valued based on publicly available quoted market prices for identical securities as of June 30, 2018. The Company determines the fair value of corporate bonds and other government-sponsored enterprise related securities with the aid of valuations provided by third parties using proprietary valuation models and analytical tools. These valuation models and analytical tools use market pricing or similar instruments that are both objective and publicly available, including matrix pricing or reported trades, benchmark yields, broker/dealer quotes, issuer spreads, two-sided markets, benchmark securities, bids and/or offers. The Company validates the valuations received from its primary pricing vendors for its Level 2 securities by examining the inputs used in that vendor’s pricing process and determines whether they are reasonable and observable. The Company also compares those valuations to recent reported trades for those securities. As of June 30, 2018 and December 31, 2017, the Company had no investments in Level 2 securities. The Company did not transfer any investments between level categories during the six months ended June 30, 2018. The valuation of the Company’s investments in auction rate securities, which includes significant unobservable inputs, is more fully described in Note 5. Activity for assets measured at fair value using significant unobservable inputs (Level 3) is presented in the table below (in thousands): Balance at December 31, 2017 $ 2,209 Total unrealized gains, excluding tax impact, included in other comprehensive loss 28 Balance at June 30, 2018 $ 2,237 Total gains or losses for the period included in net loss attributable to the change in unrealized gains or losses relating to assets still held at the reporting date $ —

Commitments and Contingencies

Commitments and Contingencies	6 Months Ended
	Jun. 30, 2018
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	7. COMMITMENTS AND CONTINGENCIES In the ordinary course of business, the Company may become a party to additional lawsuits involving various matters. The Company is unaware of any such lawsuits presently pending against it which, individually or in the aggregate, are deemed to be material to the Company’s financial condition or results of operations. The Company prosecutes its intellectual property vigorously to obtain the broadest valid scope for its patents. Due to uncertainty of the ultimate outcome of these matters, the impact on future operating results or the Company’s financial condition is not subject to reasonable estimates.

Astellas Out-License Agreements

Astellas Out-License Agreements	6 Months Ended
	Jun. 30, 2018
Astellas Out-License Agreements [Member]
Astellas License Agreements	8. ASTELLAS OUT-LICENSE AGREEMENTS In July 2011, the Company entered into license agreements with Astellas Pharma Inc., or Astellas, granting Astellas exclusive, worldwide, royalty-bearing licenses under certain of the Company's know-how and intellectual property to develop and commercialize certain products containing plasmids encoding certain forms of cytomegalovirus, glycoprotein B and/or phosphoprotein 65, including ASP0113 (TransVax™) but excluding CyMVectin™. In January 2018, Astellas announced the results from a Phase 3 trial of ASP0113 in approximately 515 CMV seropositive subjects undergoing HCT procedures. Top-line results from the Phase 3 study demonstrated that the trial did not meet its primary endpoint in CMV end organ disease. Based on these results, Astellas determined to cease further clinical development of ASP0113 and terminated the license agreement. Under the terms of the agreements, the Company was performing research and development services and manufacturing services which were being paid for by Astellas. During the three months ended June 30, 2018 and 2017, the Company recognized $0.7 million and $3.1 million, respectively, of revenue related to these contract services. During the six months ended June 30, 2018 and 2017, the Company recognized $1.2 million and $6.0 million, respectively, of revenue related to these contract services. The Company also recognized $0.2 million in license revenue under the Astellas agreements during the six months ended June 30, 2017.

Facility Lease

Facility Lease	6 Months Ended
	Jun. 30, 2018
Leases [Abstract]
Facility Lease	9. FACILITY LEASE The Company leases approximately 68,400 square feet of manufacturing, research laboratory and office space at a single site in San Diego, California. In July 2016, the term of the lease was extended for 16 months through December 2018.

Stockholders' Equity

Stockholders' Equity	6 Months Ended
	Jun. 30, 2018
Equity [Abstract]
Stockholders' Equity	1 0 . STOCKHOLDERS’ EQUITY As of the date of this filing, the Company has on file a shelf registration statement that allows it to raise up to an additional $40.0 million from the sale of common stock, preferred stock, debt securities and/or warrants. Specific terms of any offering under a shelf registration statement and the securities involved would be established at the time of sale. In November 2017, the Company sold 9,194,286 shares of its common stock in a public offering at a price of $1.75 per share, including an overallotment of 2,142,857 shares issued at a price of $1.75 per share, and pre-funded warrants to purchase 7,234,285 shares of common stock at a purchase price of $1.74 per share. Net proceeds from the offering, after deducting underwriting discounts and commissions and other offering expenses payable by the Company, totaled $26.4 million. The pre-funded warrants have an exercise price of $0.01 per share and are immediately exercisable and may be exercised at any time.

Related Party Transaction

Related Party Transaction	6 Months Ended
	Jun. 30, 2018
Related Party Transactions [Abstract]
Related Party Transaction	1 1 . RELATED PARTY TRANSACTION On April 4, 2017, the Company entered into a research collaboration agreement with AnGes. As of the date of the transaction, AnGes held 18.6% of the outstanding stock of the Company. Pursuant to the collaboration agreement, AnGes agreed to make a non-refundable payment to the Company of $750,000 and the Company agreed to conduct certain research activities related to a development program targeting chronic hepatitis B. In exchange for the payment, AnGes received an option to negotiate exclusive rights in Japan related to the program. The parties also agreed to share the costs of prosecuting and maintaining intellectual property rights arising from the research program after such costs reach a specified limit. The decision to sell, license or sublicense rights is a contingent event within the Company’s control. There are no guarantees for any outcomes of the research activities, no purchase obligations required by the Company and no debt or equity arrangements connected with the research activities. There are no other written or oral side agreements between the Company and AnGes that indicate that the funding of the research activities will be repaid. The Company is responsible for the conduct of the research activities. The upfront payment received was deferred and recognized as contract revenue as the related research costs are incurred. As of June 30, 2018, the Company had recognized the full $750,000 payment as contract revenue, with $0.1 million recognized in the three months ended June 30, 2018.

Restructuring Costs

Restructuring Costs	6 Months Ended
	Jun. 30, 2018
Restructuring And Related Activities [Abstract]
Restructuring Costs	12. RESTRUCTURING COSTS In January 2018, the Company and Astellas announced that ASP0113 did not meet its primary endpoint in a Phase 3 clinical study in CMV end organ disease, after which Astellas informed the Company that it was terminating further development. As a result, the Company restructured its operations to conserve capital, which included a staff reduction of 40 employees and the write-off of certain intangible assets. The Company recorded charges for one-time employee termination benefits of $1.1 million and for intangible asset impairments of $0.3 million during the six months ended June 30, 2018. Overhead costs associated with the former manufacturing facility of $0.6 million and $1.0 million have been recognized as general and administrative expense during the three and six months ended June 30, 2018, respectively. The following table summarizes the components of the restructuring charges (in thousands): Employee Termination Asset Benefits Impairments Total Research and development $ 272 $ 267 $ 539 Manufacturing and production 735 — 735 General and administrative 117 — 117 $ 1,124 $ 267 $ 1,391 The following table sets forth the accrual activity for employee termination benefits for the six months ended June 30, 2018 (in thousands). No additional charges are expected to be incurred. Balance at December 31, 2017 $ — Accruals 1,124 Payments (1,122 ) Balance at June 30, 2018 $ 2

Subsequent Event

Subsequent Event	6 Months Ended
	Jun. 30, 2018
Subsequent Events [Abstract]
Subsequent Event	13. SUBSEQUENT EVENT In January 2018, after the Company announced that ASP0113 did not meet its primary endpoint the Company decided to shut down its manufacturing operations. In July 2018, the Company entered into an agreement with Genopis, Inc., or Genopis, to sell the Company’s idle manufacturing assets for $1.7 million. As part of the agreement, Genopis agreed to sublease 51,400 square feet of the Company’s facility through the remaining term of the Company’s lease, which expires on December 31, 2018. Vical will continue to occupy approximately 17,000 square feet of lab and office space at no cost. Genopis was also required to sign a long-term lease with the facility’s landlord beginning on January 1, 2019. Genopis agreed to sublease 17,000 square feet of the facility to the Company at no cost for the one-year period ending on December 31, 2019. We will complete the accounting for the agreements with Genopis during the third quarter of our current fiscal year ending December 31, 2018.

Basis of Presentation (Policies

Basis of Presentation (Policies)	6 Months Ended
	Jun. 30, 2018
Accounting Policies [Abstract]
Cash, Cash Equivalents and Marketable Securities	Cash, Cash Equivalents and Marketable Securities Cash and cash equivalents consist of cash and highly liquid securities with original maturities at the date of acquisition of ninety days or less and can be liquidated without prior notice or penalty. Investments with an original maturity of more than ninety days are considered marketable securities and have been classified by management as available-for-sale. These investments are classified as current assets, even though the stated maturity date may be one year or more beyond the current balance sheet date which reflects management’s intention to use the proceeds from sales of these securities to fund its operations, as necessary. Such investments are carried at fair value, with unrealized gains and losses included as a separate component of stockholders’ equity. Realized gains and losses from the sale of available-for-sale securities or the amounts, net of tax, reclassified out of accumulated other comprehensive income (loss), if any, are determined on a specific identification basis.
Restricted Cash	Restricted Cash The Company was required to maintain a letter of credit securing an amount equal to twelve months of the then current monthly installment of base rent for the original term of the lease for its facilities, which ended on August 31, 2017. In July 2016, the term of the lease was extended for 16 months through December 2018. During the extended term, the Company is required to maintain a letter of credit securing an amount equal to $0.2 million.
Revenue Recognition	Revenue Recognition We recognize revenue when control of our products and services is transferred to our customers in an amount that reflects the consideration we expect to receive from our customers in exchange for those products and services. This process involves identifying the contract with a customer, determining the performance obligations in the contract, determining the contract price, allocating the contract price to the distinct performance obligations in the contract, and recognizing revenue when the performance obligations have been satisfied. A performance obligation is considered distinct from other obligations in a contract when it provides a benefit to the customer either on its own or together with other resources that are readily available to the customer and is separately identified in the contract. We consider a performance obligation satisfied once we have transferred control of a good or service to the customer, meaning the customer has the ability to use and obtain the benefit of the good or service. We recognize revenue for satisfied performance obligations only when we determine there are no uncertainties regarding payment terms or transfer of control.
Research and Development Costs	Research and Development Costs Research and development costs are expensed as incurred. Research and development costs include salaries and personnel-related costs, supplies and materials, outside services, costs of conducting preclinical and clinical trials, facilities costs and amortization of intangible assets. The Company accounts for its clinical trial costs by estimating the total cost to treat a patient in each clinical trial, and accruing this total cost for the patient over the estimated treatment period, which corresponds with the period over which the services are performed, beginning when the patient enrolls in the clinical trial. This estimated cost includes payments to the site conducting the trial, and patient-related lab and other costs related to the conduct of the trial. Cost per patient varies based on the type of clinical trial, the site of the clinical trial, the method of administration of the treatment, and the number of treatments that a patient receives. Treatment periods vary depending on the clinical trial. The Company makes revisions to the clinical trial cost estimates in the current period, as clinical trials progress.
Manufacturing and Production Costs	Manufacturing and Production Costs Manufacturing and production costs include expenses related to manufacturing contracts and expenses for the production of plasmid DNA for use in the Company’s research and development efforts. Production expenses related to the Company’s research and development efforts are expensed as incurred.
Net Loss Per Share	Net Loss Per Share Basic and diluted net loss per share has been computed using the weighted-average number of shares of common stock outstanding during the period. The weighted average number of shares used to compute diluted loss per share excludes any assumed exercise of stock options and warrants and any assumed issuance of common stock under restricted stock units (RSUs) as the effect would be antidilutive. Common stock equivalents of 7.2 million for the three and six months ended June 30, 2018 were excluded from the calculation because of their antidilutive effect. There were no common stock equivalents for the three and six months ended June 30, 2017.
Stock-Based Compensation	Stock-Based Compensation The Company records its compensation expense associated with stock options and other forms of equity compensation based on their fair value at the date of grant using the Black-Scholes-Merton option pricing model. Stock-based compensation includes amortization related to stock option awards based on the estimated grant date fair value. Stock-based compensation expense related to stock options is recognized ratably over the vesting period of the option. In addition, the Company records expense related to RSUs granted based on the fair value of those awards on the grant date. The fair value related to the RSUs is amortized to expense over the vesting term of those awards. Forfeitures of stock options and RSUs are recognized as they occur. Stock-based compensation expense for a stock-based award with a performance condition is recognized when the achievement of such performance condition is determined to be probable. If the outcome of such performance condition is not determined to be probable or is not met, no compensation expense is recognized and any previously recognized compensation expense is reversed.
Recent Accounting Pronouncements	Recent Accounting Pronouncements In May 2014, the Financial Accounting Standards Board (the “FASB”) issued ASU No. 2014-09, “Revenue from Contracts with Customers” which outlines a single comprehensive model for entities to use in accounting for revenue arising from contracts with customers. The Company adopted the new standard effective January 1, 2018 using the modified retrospective method applied to contracts not completed as of December 31, 2017. As it relates to process validation lots and stock piling lots completed but not delivered as of December 31, 2017 at the request of a customer, the Company concluded that, under ASC 606, the criteria for transfer of control were met prior to January 1, 2018 and as a result, Income Statement As Reported Balances Without Adoption of ASC 606 Effect of Change Increase/(Decrease) Revenues Contract revenue $ 1,431 $ 1,431 $ - Operating expenses Manufacturing and production 1,436 1,436 - Net loss (11,138 ) (11,138 ) - Balance Sheet As Reported Balances Without Adoption of ASC 606 Effect of Change Increase/(Decrease) Assets Deferred contract costs $ — $ 10,502 $ (10,502 ) Liabilities Deferred revenue 20 11,450 (11,430 ) Equity Accumulated deficit (436,948 ) (437,876 ) 928 In February 2016, the FASB issued ASU No. 2016-02, “Leases (Topic 842).” The new standard requires a lessee to record on the balance sheet the assets and liabilities for the rights and obligations created by leases with lease terms of more than 12 months and will require both lessees and lessors to disclose certain key information about lease transactions. The standard will be effective for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years. The Company is evaluating the effect that the adoption of the new guidance will have on its financial statements and related disclosures.

Basis of Presentation (Tables)

Basis of Presentation (Tables)	6 Months Ended
	Jun. 30, 2018
Accounting Policies [Abstract]
Summary of Impact of Adoption of New Accounting Standard on Income Statement and Balance Sheet	The impact of adoption on the Company’s income statement and balance sheet as of June 30, 2018 and for the six months then ended was as follows (in thousands): Income Statement As Reported Balances Without Adoption of ASC 606 Effect of Change Increase/(Decrease) Revenues Contract revenue $ 1,431 $ 1,431 $ - Operating expenses Manufacturing and production 1,436 1,436 - Net loss (11,138 ) (11,138 ) - Balance Sheet As Reported Balances Without Adoption of ASC 606 Effect of Change Increase/(Decrease) Assets Deferred contract costs $ — $ 10,502 $ (10,502 ) Liabilities Deferred revenue 20 11,450 (11,430 ) Equity Accumulated deficit (436,948 ) (437,876 ) 928

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	6 Months Ended
	Jun. 30, 2018
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Summary of Total Stock-Based Compensation Expense	Total stock-based compensation expense was allocated to research and development, manufacturing and production and general and administrative expense as follows (in thousands): Three Months Ended Six Months Ended June 30, June 30, 2018 2017 2018 2017 Research and development $ 48 $ 56 $ 76 $ 123 Manufacturing and production — 37 (68 ) 65 General and administrative 114 104 201 240 Total stock-based compensation expense $ 162 $ 197 $ 209 $ 428

Marketable Securities, Availa24

Marketable Securities, Available for Sale (Tables)	6 Months Ended
	Jun. 30, 2018
Investments Debt And Equity Securities [Abstract]
Summary of Available-for-Sale Marketable Securities	The following is a summary of available-for-sale marketable securities (in thousands): June 30, 2018 Amortized Cost Unrealized Gain Unrealized Loss Market Value U.S. treasuries $ 41,875 $ — $ 43 $ 41,832 $ 41,875 $ — $ 43 $ 41,832 December 31, 2017 Amortized Cost Unrealized Gain Unrealized Loss Market Value U.S. treasuries $ 34,462 $ — $ 29 $ 34,433 Certificates of deposit 1,225 — — 1,225 $ 35,687 $ — $ 29 $ 35,658

Other Balance Sheet Accounts (T

Other Balance Sheet Accounts (Tables)	6 Months Ended
	Jun. 30, 2018
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Summary of Accounts Payable and Accrued Expenses	Accounts payable and accrued expenses consisted of the following (in thousands): June 30, December 31, 2018 2017 Employee compensation $ 1,315 $ 2,654 Clinical trial accruals 1,315 1,017 Accounts payable 357 1,213 Employee termination benefits accrual 2 — Other accrued liabilities 172 333 Total accounts payable and accrued expenses $ 3,161 $ 5,217

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	6 Months Ended
	Jun. 30, 2018
Fair Value Disclosures [Abstract]
Summary of Cash Equivalents, Marketable Securities and Long-Term Investments Measured at Fair Value	Cash equivalents, marketable securities and long-term investments measured at fair value are classified in the table below in one of the three categories described above (in thousands): Fair Value Measurements June 30, 2018 Level 1 Level 2 Level 3 Total Money market funds 6,733 — — 6,733 U.S. treasuries 41,832 — — 41,832 Auction rate securities — — 2,237 2,237 $ 48,565 $ — $ 2,237 $ 50,802 Fair Value Measurements December 31, 2017 Level 1 Level 2 Level 3 Total Certificates of deposit $ 1,225 $ — $ — $ 1,225 Money market funds 21,760 — — 21,760 U.S. treasuries 34,433 — — 34,433 Auction rate securities — — 2,209 2,209 $ 57,418 $ — $ 2,209 $ 59,627
Summary of Activity for Assets Measured at Fair Value Using Significant Unobservable Inputs	Activity for assets measured at fair value using significant unobservable inputs (Level 3) is presented in the table below (in thousands): Balance at December 31, 2017 $ 2,209 Total unrealized gains, excluding tax impact, included in other comprehensive loss 28 Balance at June 30, 2018 $ 2,237 Total gains or losses for the period included in net loss attributable to the change in unrealized gains or losses relating to assets still held at the reporting date $ —

Restructuring Costs (Tables)

Restructuring Costs (Tables)	6 Months Ended
	Jun. 30, 2018
Restructuring And Related Activities [Abstract]
Summary of Components of Restructuring Charges	The following table summarizes the components of the restructuring charges (in thousands): Employee Termination Asset Benefits Impairments Total Research and development $ 272 $ 267 $ 539 Manufacturing and production 735 — 735 General and administrative 117 — 117 $ 1,124 $ 267 $ 1,391
Schedule of Accrual Activity for Employee Termination Benefits	The following table sets forth the accrual activity for employee termination benefits for the six months ended June 30, 2018 (in thousands). No additional charges are expected to be incurred. Balance at December 31, 2017 $ — Accruals 1,124 Payments (1,122 ) Balance at June 30, 2018 $ 2

Basis of Presentation - Additio

Basis of Presentation - Additional Information (Detail) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended		6 Months Ended
	Jul. 31, 2016	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Jan. 01, 2018	Dec. 31, 2017
Basis Of Presentation [Line Items]
Maximum period for cash and highly liquid securities with original maturities				90 days or less
Minimum period for marketable securities classified as available-for-sale with original maturities				More than 90 days
Amount of letter of credit, description				The Company was required to maintain a letter of credit securing an amount equal to twelve months of the then current monthly installment of base rent for the original term of the lease for its facilities, which ended on August 31, 2017.
Renewal period for lease for lease beyond its expiration	16 months
Renewal lease agreement expiry date	Dec. 31, 2018
Secured letter of credit for the extended lease term		$ 200		$ 200
Common stock equivalents excluded from the calculation of diluted net income per share		7,200,000	0	7,200,000	0
Deferred contract costs							$ 10,502
ASU No. 2014-09 [Member]
Basis Of Presentation [Line Items]
Deferred revenue						$ 11,400
Deferred contract costs						10,500
Adjustment to beginning retained earnings due to adoption of new accounting standard						$ 900

Basis of Presentation - Summary

Basis of Presentation - Summary of Impact of Adoption of New Accounting Standard on Income Statement and Balance Sheet (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Jan. 01, 2018	Dec. 31, 2017
Revenues:
Contract revenue	$ 725	$ 3,369	$ 1,431	$ 6,270
Operating expenses:
Manufacturing and production		1,602	1,436	2,911
Net loss	(4,868)	$ (3,320)	(11,138)	$ (6,144)
Assets
Deferred contract costs						$ 10,502
Equity
Accumulated deficit	(436,948)		(436,948)			$ (426,738)
Balances Without Adoption of ASC 606 [Member]
Revenues:
Contract revenue			1,431
Operating expenses:
Manufacturing and production			1,436
Net loss			(11,138)
Assets
Deferred contract costs	10,502		10,502
Liabilities
Deferred revenue	11,450		11,450
Equity
Accumulated deficit	(437,876)		(437,876)
ASU No. 2014-09 [Member]
Assets
Deferred contract costs					$ 10,500
Liabilities
Deferred revenue					$ 11,400
As Reported [Member]
Revenues:
Contract revenue			1,431
Operating expenses:
Manufacturing and production			1,436
Net loss			(11,138)
Assets
Deferred contract costs	0		0
Liabilities
Deferred revenue	20		20
Equity
Accumulated deficit	(436,948)		(436,948)
Restatement Adjustment [Member] | ASU No. 2014-09 [Member] | Effect of Change Increase/(Decrease) [Member]
Revenues:
Contract revenue			0
Operating expenses:
Manufacturing and production			0
Net loss			0
Assets
Deferred contract costs	(10,502)		(10,502)
Liabilities
Deferred revenue	(11,430)		(11,430)
Equity
Accumulated deficit	$ 928		$ 928

Stock-Based Compensation - Summ

Stock-Based Compensation - Summary of Total Stock-Based Compensation Expense (Detail) - 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]
Total stock-based compensation expense	$ 162	$ 197	$ 209	$ 428
Research and development [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	48	56	76	123
Manufacturing and production [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	0	37	(68)	65
General and administrative [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	$ 114	$ 104	$ 201	$ 240

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional Information (Detail) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Estimated value of stock-based awards, granted	$ 0.4	$ 0.7
Unrecognized compensation cost related to unvested options	$ 0.5
Unvested stock-based awards expected to be recognized, weighted-average period	1 year 4 months 24 days
Portion of stock-based awards granted from outstanding common shares	2.50%	5.10%

Marketable Securities, Availa32

Marketable Securities, Available for Sale - Summary of Available-for-Sale Marketable Securities (Detail) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 41,875	$ 35,687
Unrealized Gain	0	0
Unrealized Loss	43	29
Market Value	41,832	35,658
U.S. treasuries [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	41,875	34,462
Unrealized Gain	0	0
Unrealized Loss	43	29
Market Value	$ 41,832	34,433
Certificates of deposit [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost		1,225
Unrealized Gain		0
Unrealized Loss		0
Market Value		$ 1,225

Marketable Securities, Availa33

Marketable Securities, Available for Sale - Additional Information (Detail)	6 Months Ended
	Jun. 30, 2018USD ($)
Investments Debt And Equity Securities [Abstract]
Available-for-sale securities maturing outside of one year	$ 0
Realized gains or losses on sales of available-for-sale securities	0
Available-for-sale securities in a continuous material unrealized loss position longer than one year	$ 0

Other Balance Sheet Accounts -

Other Balance Sheet Accounts - Summary of Accounts Payable and Accrued Expenses (Detail) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Payables And Accruals [Abstract]
Employee compensation	$ 1,315	$ 2,654
Clinical trial accruals	1,315	1,017
Accounts payable	357	1,213
Employee termination benefits accrual	2	0
Other accrued liabilities	172	333
Total accounts payable and accrued expenses	$ 3,161	$ 5,217

Other Balance Sheet Accounts 35

Other Balance Sheet Accounts - Additional Information (Detail) $ in Millions	Jun. 30, 2018USD ($)
Receivables and Other Assets [Member] | Idle Manufacturing Equipment [Member]
Property Plant And Equipment [Line Items]
Net book value of asset classified as held for sale	$ 0.3

Long-Term Investments - Additio

Long-Term Investments - Additional Information (Detail) - USD ($)	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Investment [Line Items]
Auction rate securities held, at par value	$ 2,500,000
Maturity of long-term investment	2,038
Recognized cumulative losses	$ 400,000
Unrealized gains on auction rate securities	22,000	$ 74,000
Cumulative unrealized gains	400,000
Carrying value of auction rate security	$ 2,237,000		$ 2,209,000
Assumed interest rate	5.73%
Estimated redemption period	5 years
Recognized cumulative losses realized	$ 0
Discount Rate [Member]
Investment [Line Items]
Fair value input discount rate	1

Fair Value Measurements - Summa

Fair Value Measurements - Summary of Cash Equivalents, Marketable Securities and Long-Term Investments Measured at Fair Value (Detail) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	$ 50,802	$ 59,627
Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	48,565	57,418
Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	0	0
Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	2,237	2,209
Money market funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	6,733	21,760
Money market funds [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	6,733	21,760
Money market funds [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	0	0
Money market funds [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	0	0
U.S. treasuries [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	41,832	34,433
U.S. treasuries [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	41,832	34,433
U.S. treasuries [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	0	0
U.S. treasuries [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	0	0
Auction rate securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	2,237	2,209
Auction rate securities [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	0	0
Auction rate securities [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	0	0
Auction rate securities [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	$ 2,237	2,209
Certificates of deposit [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value		1,225
Certificates of deposit [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value		1,225
Certificates of deposit [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value		0
Certificates of deposit [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value		$ 0

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Detail) - USD ($)	Jun. 30, 2018	Dec. 31, 2017
Level 2 [Member]
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Investments	$ 0	$ 0

Fair Value Measurements - Sum39

Fair Value Measurements - Summary of Activity for Assets Measured at Fair Value Using Significant Unobservable Inputs (Detail) $ in Thousands	6 Months Ended
	Jun. 30, 2018USD ($)
Fair Value Disclosures [Abstract]
Balance at December 31, 2017	$ 2,209
Total unrealized gains, excluding tax impact, included in other comprehensive loss	28
Balance at June 30, 2018	2,237
Total gains or losses for the period included in net loss attributable to the change in unrealized gains or losses relating to assets still held at the reporting date	$ 0

Astellas Out-License Agreemen40

Astellas Out-License Agreements - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Revenue recognized	$ 725	$ 3,369	$ 1,431	$ 6,270
Collaborative Arrangement [Member] | Astellas Out-License Agreements [Member] | Contract Services [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Revenue recognized	$ 700	$ 3,100	$ 1,200	6,000
Collaborative Arrangement [Member] | Astellas Out-License Agreements [Member] | License Revenue [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Revenue recognized				$ 200

Facility Lease - Additional Inf

Facility Lease - Additional Information (Detail) - ft²	1 Months Ended
	Jul. 31, 2016	Nov. 30, 2013
Facility Lease [Line Items]
Renewal period for lease for lease beyond its expiration	16 months
Renewal lease agreement expiry date	Dec. 31, 2018
California [Member]
Facility Lease [Line Items]
Area for leasing facility of manufacturing, research laboratory and office space		68,400
Renewal period for lease for lease beyond its expiration	16 months
Renewal lease agreement expiry date	Dec. 31, 2018

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Detail) - USD ($)	1 Months Ended	6 Months Ended
	Nov. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Stockholders Equity [Line Items]
Sale of common stock, preferred stock, debt securities and warrants		$ 40,000,000
Net proceeds from offering		$ 1,000	$ 312,000
Common Stock [Member]
Stockholders Equity [Line Items]
Pre-funded warrants to purchase common stock	7,234,285
Pre-funded warrants to purchase common stock, price per share	$ 1.74
Net proceeds from offering	$ 26,400,000
Pre-funded warrants exercise price per share	$ 0.01
Public Offering [Member] | Common Stock [Member]
Stockholders Equity [Line Items]
Shares issued	9,194,286
Public offering, price per share	$ 1.75
Overallotment [Member] | Common Stock [Member]
Stockholders Equity [Line Items]
Shares issued	2,142,857
Public offering, price per share	$ 1.75

Related Party Transaction - Add

Related Party Transaction - Additional Information (Detail) - USD ($)	Apr. 04, 2017	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Related Party Transaction [Line Items]
Contract revenue		$ 725,000	$ 3,369,000	$ 1,431,000	$ 6,270,000
Research Collaboration Agreement [Member] | AnGes MG, Inc [Member]
Related Party Transaction [Line Items]
Percentage of common stock outstanding	18.60%
Non- refundable amount receivable under research collaboration agreement	$ 750,000
Contract revenue		$ 100,000		$ 750,000

Restructuring Costs - Additiona

Restructuring Costs - Additional Information (Detail) $ in Thousands	1 Months Ended	3 Months Ended		6 Months Ended
	Jan. 31, 2018Employee	Jun. 30, 2018USD ($)	Jun. 30, 2017USD ($)	Jun. 30, 2018USD ($)	Jun. 30, 2017USD ($)
Restructuring Cost And Reserve [Line Items]
Number of staff reduced | Employee	40
One-time employee termination benefits				$ 1,100
Overhead costs associated with manufacturing facility			$ 1,602	1,436	$ 2,911
Intangible asset impairment charges				267
General and administrative [Member]
Restructuring Cost And Reserve [Line Items]
Overhead costs associated with manufacturing facility		$ 600		1,000
Intangible asset impairment charges				$ 0

Restructuring Costs - Summary o

Restructuring Costs - Summary of Components of Restructuring Charges (Detail) $ in Thousands	6 Months Ended
	Jun. 30, 2018USD ($)
Restructuring Cost And Reserve [Line Items]
Employee Termination Benefits	$ 1,124
Asset Impairments	267
Total	1,391
Research and development [Member]
Restructuring Cost And Reserve [Line Items]
Employee Termination Benefits	272
Asset Impairments	267
Total	539
Manufacturing and production [Member]
Restructuring Cost And Reserve [Line Items]
Employee Termination Benefits	735
Asset Impairments	0
Total	735
General and administrative [Member]
Restructuring Cost And Reserve [Line Items]
Employee Termination Benefits	117
Asset Impairments	0
Total	$ 117

Restructuring Costs - Schedule

Restructuring Costs - Schedule of Accrual Activity for Employee Termination Benefits (Detail) - Employee Termination Benefits [Member] $ in Thousands	6 Months Ended
	Jun. 30, 2018USD ($)
Restructuring Cost And Reserve [Line Items]
Balance at December 31, 2017	$ 0
Accruals	1,124
Payments	(1,122)
Balance at June 30, 2018	$ 2

Subsequent Event - Additional I

Subsequent Event - Additional Information (Detail) - Subsequent Event [Member]	Jul. 31, 2018USD ($)ft²
Subsequent Event [Line Items]
Area of square feet to be occupied | ft²	17,000
Facility lease cost | $	$ 0
Genopis, Inc [Member]
Subsequent Event [Line Items]
Sale of idle manufacturing assets | $	$ 1,700,000
Genopis, Inc [Member] | Period Through December 31, 2018 [Member]
Subsequent Event [Line Items]
Area of square feet agreed to sublease of facility | ft²	51,400
Sublease expiration date	Dec. 31, 2018
Genopis, Inc [Member] | Period Ending December 31, 2019 [Member]
Subsequent Event [Line Items]
Area of square feet agreed to sublease of facility | ft²	17,000
Sublease expiration date	Dec. 31, 2019
Facility lease cost | $	$ 0
Long-term lease beginning date	Jan. 1, 2019
Facilty sublease expiration period	1 year