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Document and Entity Information - USD ($)	12 Months Ended
Document and Entity Information - USD ($)	Dec. 31, 2018	Feb. 27, 2019	Jun. 30, 2018
Document and Entity Information [Abstract]
Entity Registrant Name	NEWLINK GENETICS CORP
Entity Central Index Key	0001126234
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Document Type	10-K
Document Period End Date	Dec. 31, 2018
Document Fiscal Year Focus	2018
Document Fiscal Period Focus	FY
Amendment Flag	false
Entity Common Stock, Shares Outstanding		37,276,102
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Public Float			$ 137,519,199
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Shell Company	false

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 120,738	$ 158,708
Prepaid expenses and other current assets	5,536	6,226
Current income tax receivable	339	356
Other receivables	459	10,176
Total current assets	127,072	175,466
Non-current assets:
Property and equipment, net	3,727	5,091
Income tax receivable	140	140
Total non-current assets	3,867	5,231
Total assets	130,939	180,697
Current liabilities:
Accounts payable	555	9,256
Accrued expenses	8,139	12,467
Current portion of unearned revenue	0	56
Current portion of deferred rent	92	92
Current portion of notes payable and obligations under capital leases	61	160
Total current liabilities	8,847	22,031
Long term liabilities:
Royalty obligation payable to Iowa Economic Development Authority	6,000	6,000
Notes payable and obligations under capital leases	43	111
Deferred rent	906	998
Total long-term liabilities	6,949	7,109
Total liabilities	15,796	29,140
Stockholders' Equity:
Blank check preferred stock, $0.01 par value: Authorized shares — 5,000,000 at December 31, 2018 and 2017; issued and outstanding shares — 0 at December 31, 2018 and 2017	0	0
Common stock, $0.01 par value: Authorized shares — 75,000,000 at December 31, 2018 and 2017; issued 37,343,547 and 37,168,122 at December 31, 2018 and 2017, respectively and outstanding 37,251,220 and 37,109,556 at December 31, 2018 and 2017, respectively	373	372
Additional paid-in capital	407,199	389,786
Treasury stock, at cost: 92,327 and 58,566 shares at December 31, 2018 and 2017	(1,417)	(1,142)
Accumulated deficit	(291,012)	(237,459)
Total stockholders' equity	115,143	151,557
Total liabilities and stockholders' equity	$ 130,939	$ 180,697

Consolidated Balance Sheets (Parentheticals) - $ / shares	Dec. 31, 2018	Dec. 31, 2017
Stockholders' Equity:
Blank check preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Blank check preferred stock, authorized shares	5,000,000	5,000,000
Blank check preferred stock, issued shares	0	0
Blank check preferred stock, outstanding shares	0	0
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, authorized shares	75,000,000	75,000,000
Common stock, issued shares	37,343,547	37,168,122
Common stock, outstanding shares	37,251,220	37,109,556
Treasury stock, shares	92,327	58,566

Consolidated Statements of Operations - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Licensing and collaboration revenue	$ 1,206	$ 390	$ 3,526
Total operating revenues	12,474	28,711	35,768
Operating expenses:
Research and development	45,694	69,866	93,300
General and administrative	29,218	31,726	33,226
Total operating expenses	74,912	101,592	126,526
Loss from operations	(62,438)	(72,881)	(90,758)
Other income and expense:
Miscellaneous (expense) income	(102)	(126)	32
Interest income	2,029	616	237
Interest expense	(52)	(119)	(22)
Other income, net	1,875	371	247
Loss before taxes	(60,563)	(72,510)	(90,511)
Income tax benefit	6,968	559	5,356
Net loss	$ (53,595)	$ (71,951)	$ (85,155)
Basic and diluted loss per share (in dollars per share)	$ (1.44)	$ (2.30)	$ (2.94)
Basic and diluted average shares outstanding (in shares)	37,191,262	31,304,309	28,979,327
Grant [Member]
Total operating revenues	$ 11,268	$ 28,321	$ 32,242

Consolidated Statements of Equity - USD ($) $ in Thousands	Total	IPO	Common Stock	Common Stock IPO	Additional Paid-in Capital	Additional Paid-in Capital IPO	Treasury Stock	Accumulated Deficit
Balance at beginning of period at Dec. 31, 2015	$ 195,774		$ 288		$ 276,610		$ (771)	$ (80,353)
Balance (shares) at Dec. 31, 2015			28,814,142
Increase (Decrease) in Stockholders' Equity
Share-based compensation	16,707				16,707
Exercise of stock options and vesting of restricted stock awards (in shares)			296,933
Exercise of stock options and vesting of restricted stock awards	1,679		$ 4		1,675
Sales of shares under stock purchase plan (shares)			58,609
Sales of shares under stock purchase plan	543				543
Shares withheld for statutory tax withholding (in shares)			(6,011)
Shares withheld for statutory tax withholding	(82)						(82)
Net loss	(85,155)							(85,155)
Balance at end of period at Dec. 31, 2016	129,466		$ 292		295,535		(853)	(165,508)
Balance (shares) at Dec. 31, 2016			29,163,673
Increase (Decrease) in Stockholders' Equity
Share-based compensation	18,508				18,508
Exercise of stock options and vesting of restricted stock awards (in shares)			212,961
Exercise of stock options and vesting of restricted stock awards	962		$ 2		960
Sales of shares under stock purchase plan (shares)			70,787
Sales of shares under stock purchase plan	445		$ 1		444
Issuance of common stock (net of offering costs) (in shares)			1,940,656	5,750,000
Issuance of common stock (net of offering costs)	19,333	$ 55,083	$ 19	$ 58	19,314	$ 55,025
Shares withheld for statutory tax withholding (in shares)			(28,521)
Shares withheld for statutory tax withholding	(289)						(289)
Net loss	(71,951)							(71,951)
Balance at end of period at Dec. 31, 2017	$ 151,557		$ 372		389,786		(1,142)	(237,459)
Balance (shares) at Dec. 31, 2017	37,109,556		37,109,556
Increase (Decrease) in Stockholders' Equity
Share-based compensation	$ 17,120				17,120
Exercise of stock options and vesting of restricted stock awards (in shares)			126,938
Exercise of stock options and vesting of restricted stock awards	143		$ 1		142
Sales of shares under stock purchase plan (shares)			48,487
Sales of shares under stock purchase plan	151				151
Shares withheld for statutory tax withholding (in shares)			(33,761)
Shares withheld for statutory tax withholding	(275)						(275)
Cumulative effect of accounting change	42							42
Net loss	(53,595)							(53,595)
Balance at end of period at Dec. 31, 2018	$ 115,143		$ 373		$ 407,199		$ (1,417)	$ (291,012)
Balance (shares) at Dec. 31, 2018	37,251,220		37,251,220

Consolidated Statements of Equity (Parentheticals) $ in Thousands	12 Months Ended
	Dec. 31, 2017 USD ($)
Issuance costs of common stock under the ATM Offering	$ 561
IPO
Issuance costs of common stock under the ATM Offering	$ 3,700

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Cash Flows From Operating Activities
Net loss	$ (53,595)	$ (71,951)	$ (85,155)
Adjustments to reconcile net loss to net cash used in operating activities:
Share-based compensation	17,120	18,508	16,707
Depreciation and amortization	1,145	1,407	2,084
Forgiveness of debt	0	0	(397)
Impairment of fixed assets	0	0	3,958
Loss on sale of fixed assets	102	126	0
Changes in operating assets and liabilities:
Prepaid expenses and other assets	226	(305)	(965)
Other receivables	10,223	14,350	(19,139)
Accounts payable and accrued expenses	(13,029)	(15,469)	24,770
Income taxes payable (receivable)	17	5,479	(6,834)
Unearned revenue	(56)	(335)	(68)
Deferred rent	(92)	(91)	(908)
Net cash used in operating activities	(37,939)	(48,281)	(65,947)
Cash Flows From Investing Activities
Maturity of certificates of deposit	0	0	2,180
Purchase of equipment	(7)	(43)	(2,246)
Proceeds on sale of fixed assets	124	254	0
Net cash provided by (used in) investing activities	117	211	(66)
Cash Flows From Financing Activities
Issuance of common stock, net of offering costs	0	74,416	0
Issuance of common stock under share-based compensation plans	294	1,407	2,222
Repurchase of common stock	(275)	(289)	(82)
Payments under capital lease obligations and principal payments on notes payable	(167)	(246)	(257)
Net cash (used) provided by financing activities	(148)	75,288	1,883
Net (decrease) increase in cash and cash equivalents	(37,970)	27,218	(64,130)
Cash and cash equivalents at beginning of year	158,708	131,490	195,620
Cash and cash equivalents at end of year	120,738	158,708	131,490
Supplemental disclosure of cash flows information:
Cash paid for interest	8	15	22
Cash paid for taxes	25	643	1,022
Proceeds from income tax refunds	7,057	6,651	197
Noncash financing and investing activities:
Assets acquired under capital lease	$ 0	$ 0	$ 231

Description of Business Activities	12 Months Ended
Description of Business Activities	Dec. 31, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Description of Business Activities	Description of Business Activities NewLink Genetics Corporation (NewLink) was incorporated as a Delaware corporation on June 4, 1999 and initiated operations in April of 2000. NewLink and its subsidiaries (the Company) are devoting substantially all of their efforts toward research and development. The Company has incurred significant losses in all years since being incorporated, except for the year ended December 31, 2014, and has never generated revenue from commercial sales of its drugs. The accompanying financial statements as of and for the year ended December 31, 2018 have been prepared assuming the Company will continue as a going concern. The Company raised net proceeds of $37.6 million from its IPO, completed a follow-on offering of its common stock raising net proceeds of $49.0 million, and raised an additional $58.7 million in net proceeds from an at the market offering prior to March 31, 2015. During 2017, the Company sold 1,940,656 shares of its common stock under an ATM offering, with aggregate net proceeds of $19.3 million after commissions of $398,000 paid to Cantor Fitzgerald & Co. (Cantor) as the placement agent, and other costs of $163,000. In October 2017, the Company sold 5,750,000 of its shares of common stock in a public offering for aggregate net proceeds of $55.2 million after underwriters' discounts, commissions and other expenses of $3.7 million. The Company's cash and cash equivalents are expected to be adequate to satisfy the Company's liquidity requirements through 2021. If available liquidity becomes insufficient to meet the Company’s operating obligations as they come due, the Company's plans include pursuing alternative funding arrangements and/or reducing expenditures as necessary to meet the Company’s cash requirements. However, there is no assurance that, if required, the Company will be able to raise additional capital or reduce discretionary spending to provide the required liquidity. Failure by the Company to successfully execute its plans or otherwise address its liquidity needs may have a material adverse effect on its business and financial position, and may materially affect the Company’s ability to continue as a going concern.

Significant Accounting Policies	12 Months Ended
Significant Accounting Policies	Dec. 31, 2018
Accounting Policies [Abstract]
Significant Accounting Policies	Significant Accounting Policies Use of Estimates The preparation of consolidated financial statements in conformity with U.S. generally accepted accounting principles, or U.S. GAAP, requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the consolidated financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. Principles of Consolidation The consolidated financial statements include the financial statements of NewLink and its wholly owned subsidiaries. All intercompany balances and transactions have been eliminated in consolidation. Cash and Cash Equivalents For the purposes of the consolidated statements of cash flows, the Company considers all highly liquid debt instruments with an original maturity of three months or less to be cash equivalents. Cash and cash equivalents of $120.7 million and $158.7 million at December 31, 2018 and 2017, respectively, consist of checking accounts, money market accounts and treasury bills. Leasehold Improvements and Equipment, and Deferred Rent Leasehold improvements and equipment are capitalized as the Company believes they have alternative future uses and are stated at cost. Equipment under capital leases is stated at the present value of future minimum lease payments. Depreciation on all leasehold improvements and equipment is calculated on the straight-line method over the shorter of the lease term or estimated useful life of the asset. Computer equipment has useful lives of three to five years, lab equipment has a useful life of five years and contract manufacturing organization equipment has a useful life of five years. Deferred rent reflects improvement allowances from the Company's lessors deferred to be recognized as part of lease expense over the remaining term of the lease, which is recognized on a straight-line basis. Total deferred rents were $998,000 and $1.1 million as of December 31, 2018 and 2017, respectively. Impairment of Long-Lived Assets Long-lived assets are reviewed for impairment whenever changes in circumstances indicate that the carrying amount of an asset may not be recoverable. Recoverability of assets to be held and used is measured by a comparison of the carrying amount of an asset group to future net undiscounted cash flows expected to be generated by the asset group, primarily relating to proceeds for selling the assets. If such assets are considered to be impaired, the impairment to be recognized is measured at the amount by which the carrying amount of the assets exceeds the fair value of the assets. Assets to be disposed of are reported at the lower of the carrying amount or fair value less costs to sell. Revenue Recognition Revenues are recognized under Topic 606 when control of the promised goods or services is transferred to the Company's customers, in an amount that reflects the consideration the Company expects to be entitled to in exchange for those goods or services. The Company receives payments from government entities under its grants and contracts with the Department of Defense and the United States Department of Health and Human Services, or HHS. These agreements provide the Company cost reimbursement plus a percentage for certain types of expenditures in return for research and development activities over a contractually defined period. Grant revenues are recognized over time and measured using the input method. The Company uses labor costs and subcontractor fees as inputs to measure progress towards satisfying its performance obligations under these agreements. This is the most faithful depiction of the transfer of goods and services to the government entities due to the government entities’ control over the research and development activities. Under this method, the Company recognizes revenue generally in the period during which the related costs are incurred, in an amount that reflects the consideration the Company expects to be entitled to in exchange for those goods or services. During the years ended December 31, 2018, 2017, and 2016, the Company has earned $11.3 million, $28.3 million, and $32.2 million in grant revenue, respectively. The Company had $309,000 and $9.3 million of receivables from the government contracts recorded in other receivables and $0 and $465,000 of unbilled expenses relating to the government contracts recorded in prepaid expenses and other assets on the balance sheet as of December 31, 2018 and 2017, respectively. The Company had $54,000 and $1.8 million of accrued expenses for subcontractor fees and $161,000 and $4.9 million of subcontractor fees in accounts payable for amounts incurred under the government contracts as of December 31, 2018 and 2017, respectively. Expenses Accrued Under Contractual Arrangements with Third Parties; Accrued Clinical Expenses The Company estimates its accrued expenses through a process of reviewing open contracts and purchase orders, communicating with personnel to identify services that have been performed and estimating the level of service performed and the associated cost incurred for the service that may not be invoiced from the provider. The estimates of accrued expenses as of each balance sheet date are based on facts and circumstances known at that time. Such estimates are periodically confirmed with the service providers to verify accuracy. The Company bases its expenses related to clinical trials on estimates of the services received and efforts expended pursuant to contracts with multiple research institutions and contract research organizations that conduct and manage clinical trials on behalf of the Company. Invoicing from third-party contractors for services performed can lag several months. The Company accrues the costs of services rendered in connection with third-party contractor activities based on its estimate of management fees, site management and monitoring costs and data management costs as contracted. Differences between actual clinical trial costs and estimated clinical trial costs are adjusted for in the period in which they become known through operations. Research and Development Research and development costs are expensed as incurred. Research and development expenses consist primarily of employee-related expenses, which include salaries, bonuses, benefits and share-based compensation; manufacturing-related costs; clinical trial expenses which include expenses incurred under agreements with contract research organizations, investigative sites and consultants that conduct our clinical trials; facilities, depreciation of fixed assets and other allocated expenses, which include direct and allocated expenses for rent and maintenance of research facilities and equipment; license fees for and milestone payments related to in-licensed products and technology; and costs associated with non-clinical activities and regulatory approvals. Patents The Company generally applies for patent protection on processes and products. Patent application costs are expensed as incurred as a component of general and administrative expense, as recoverability of such expenditures is uncertain. Income Taxes Income taxes are accounted for under the asset and liability method. Deferred tax assets and liabilities are recognized for the estimated future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases and operating loss and tax credit carryforwards. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in operating results in the period that includes the enactment date. Management assesses the realizability of deferred tax assets and records a valuation allowance if it is more likely than not that all or a portion of the deferred tax assets will not be realized. The Company accounts for the effect of any uncertain tax positions based on a more likely than not threshold to the recognition of the tax positions being sustained based on the technical merits of the position under scrutiny by the applicable taxing authority. If a tax position or positions are deemed to result in uncertainties of those positions, the unrecognized tax position is estimated based on a cumulative probability assessment that aggregates the estimated tax liability for all uncertain tax positions. Interest and penalties assessed, if any, are recorded in its consolidated statement of operations in interest expense and other expenses. As of December 31, 2018 and 2017, the Company had a recognized uncertain tax position of $653,000. Share-Based Compensation The Company is required to estimate the grant-date fair value of share-based payment transactions with employees which include stock options, restricted stock units (RSUs) and performance shares (PSUs) and recognizes the compensation cost over the requisite service period based on the estimated fair values as well as expected forfeiture rates. The Company estimates the fair value of each award granted using the Black-Scholes option pricing model. The Black-Scholes model requires the input of assumptions, including the expected stock price volatility, the calculation of expected term and the fair value of the underlying common stock on the date of grant, among other inputs. The Company calculates the fair value of the award on the grant date, which is the date the award is authorized by the Board of Directors or Chief Executive Officer and the employee has an understanding of the terms of the award. Generally, the Company has issued employee awards that vest either monthly or 25% vest on the first anniversary date of issuance with the remaining options vesting ratably over the next 36 months. The Company records compensation cost on a straight-line basis over the vesting period. The fair value of RSUs that are subject to cliff vesting are recognized as compensation expense over the requisite service period using the straight line attribution method, and the fair value of RSUs that are subject to graded vesting are recognized as compensation expense over the requisite service period using the accelerated attribution method. The fair value of PSUs are recognized as compensation expense beginning at the time in which the performance conditions are deemed probable of achievement, over the remaining requisite service period. The Company has issued awards to nonemployee consultants and advisers. All grants to nonemployees are valued using the same fair value method that we use for grants to employees. The compensation cost on these awards is measured each period until vesting, and is recognized through the earlier of the vesting of the award or completion of services by the nonemployee. Following is a description of the inputs for the Black-Scholes model: Exercise Price The Company uses the quoted market price as listed on the public exchange on the date of grant. If Incentive Stock Options are granted to a 10% stockholder in the Company, the exercise price shall not be less than 110% of the common stock’s fair market value on the date of grant. Expected Term (in Years) The expected term of a stock option is the period of time for which the option is expected to be outstanding. The Company uses historical exercise and option expiration data to estimate the expected term for the Black-Scholes grant-date valuation. Risk-Free Interest Rate The Company uses the average yield on current U.S. Treasury instruments with terms that approximate the expected term of the stock options being valued. Expected Dividend Yield The expected dividend yield for all of the Company’s stock option grants is 0%, as the Company has not declared a cash dividend since inception and has no plans to declare a dividend. Expected Volatility The Company uses its historical stock price volatility. The volatility is calculated over a period of time commensurate with the expected term for the options granted. Forfeitures The share-based compensation expense has been reduced for estimated forfeitures. The estimated forfeiture rate is based on historical experience of the Company’s option plan, which the Company expects to continue at the current level, and any adjustments in the forfeiture rate in the future will result in a cumulative adjustment in the period that this estimate is changed. Ultimately, the total compensation expense recognized for any given stock-based award over its vesting period will only be for those shares that actually vest. Segments The Company operates in one segment. The Company conducts research and development activities based from facilities located in Ames, Iowa and has corporate headquarters in Ames, Iowa and Austin, Texas. The Company conducts preclinical and clinical research in the biopharmaceutical industry. The chief operating decision maker uses cash flow as the primary measure to manage the business and management does not segment its business for internal reporting or decision-making. Financial Instruments and Concentrations of Credit Risk The fair values of cash and cash equivalents, receivables and accounts payable, which are recorded at cost, approximate fair value based on the short-term nature of these financial instruments. The fair value of notes payable and capital lease obligations was $104,000 and $271,000 as of December 31, 2018 and 2017, respectively, and was determined using Level 2 inputs (computed in accordance with ASC 820). The Company is unable to estimate the fair value of the royalty obligation based on future product sales as the timing of payments, if any, is uncertain. Financial instruments that potentially subject the Company to concentrations of credit risk consist primarily of cash and cash equivalents. Cash and cash equivalents are held by financial institutions and are federally insured up to certain limits. At times, the Company’s cash and cash equivalents balance exceeds the federally insured limits. To limit the credit risk, the Company invests its excess cash primarily in high quality securities such as money market funds. Earnings per share (EPS) The Company computes basic EPS attributable to the Company's common stockholders by dividing net income (loss) attributable to the Company by our weighted-average common shares outstanding during the period. Diluted EPS reflects the potential dilution beyond shares for basic EPS that could occur if securities or other contracts to issue common stock were exercised, converted into common stock, or resulted in the issuance of common stock that would have shared in our earnings. The Company computes basic and diluted EPS using net income (loss) attributable to the Company's common stockholders, and its actual weighted-average shares. Concentration of Revenue Genentech, a member of the Roche Group, and Merck Sharpe and Dohme Corp., or Merck, accounted for 0.4% and 9.2%, respectively, of the $12.5 million of revenue for the year ended December 31, 2018, with the remainder obtained from government grants. Genentech and Merck accounted for 1.2% and 0.2%, respectively, of the $28.7 million of revenue earned for the year ended December 31, 2017, with the remainder obtained from government grants. Genentech and Merck accounted for 7.6% and 2.3%, respectively, of the $35.8 million of revenue earned for the year ended December 31, 2016, with the remainder obtained from government grants. Recently Adopted Accounting Pronouncements On May 28, 2014, the FASB issued ASU No. 2014-09 (Topic 606), Revenue from Contracts with Customers. Topic 606 supersedes the revenue recognition requirements in Topic 605 “Revenue Recognition” (Topic 605), and requires entities to recognize revenue when control of the promised goods or services is transferred to customers at an amount that reflects the consideration to which the entity expects to be entitled to in exchange for those goods or services. The Company adopted Topic 606 as of January 1, 2018, and as a result, changed its accounting policy for revenue recognition, as discussed in Note 3. Recent Accounting Pronouncements In February 2016, the FASB issued ASU No. 2016-02 (Topic 842), Leases, to improve financial reporting for leasing transactions. The Company will adopt the standard on January 1, 2019 using the modified retrospective method, as required, applying the new standard to all leases existing as of the date of initial application. The Company has elected that the date of initial application will be the effective date, or January 1, 2019. Consequently, financial information will not be updated and the disclosures required under the new standard will not be provided for dates and periods before January 1, 2019. The new standard provides a number of optional practical expedients in transition. The Company expects to elect the ‘package of practical expedients’, which permits the Company not to reassess under the new standard its prior conclusions about lease identification, lease classification and initial direct costs. The Company does not expect to elect the use-of-hindsight or the practical expedient pertaining to land easements; the latter not being applicable to the Company. The Company expects that this standard will have a material effect on its consolidated balance sheet due to the recognition of right-of-use assets and lease liabilities. While the Company continues to assess all of the effects of adoption, the Company expects it to primarily relate to the operating leases for office and laboratory space noted in "Part I. Item 2. Properties" of this Annual Report on Form 10-K, for which the Company will record a lease liability and corresponding right-of-use asset upon adoption. The lease liability will equal the present value of unpaid minimum lease payments for operating leases that exist as of the date of initial application of the new standard. Future undiscounted obligations related to facility leases in effect as of the date of initial application of the new standard are included in the table of future minimum lease payments disclosed in Note 4, and aggregate to $11.4 million.

Revenues

12 Months Ended

Dec. 31, 2018

Revenue from Contract with Customer [Abstract]

Revenues

Adoption of ASC Topic 606, "Revenue from Contracts with Customers"

On January 1, 2018, we adopted Topic 606 using the modified retrospective method by recognizing the cumulative effect of initially applying Topic 606 as an adjustment to the opening balance of equity as of January 1, 2018. Therefore results for reporting periods beginning after January 1, 2018 are presented under Topic 606, while prior period amounts are not adjusted and continue to be reported in accordance with our historic accounting policy under Topic 605. The change in accounting policy from Topic 605 to Topic 606 impacted how the Company recognizes revenue from government grants and collaboration revenues, however, it did not impact the accounting for our historical license and collaboration agreements, due to the nature of those services in the period leading up to the adoption of Topic 606.

The Company recorded an immaterial net reduction to the opening accumulated deficit within equity as of January 1, 2018 due to the cumulative impact of adopting Topic 606 with respect to grants from government entities which were not completed as of the date of adoption. As a result of applying the modified retrospective method to adopt the new revenue guidance, the following adjustments were made to accounts on the Consolidated Balance Sheet as of January 1, 2018 (in thousands):


	As Reported				Adjusted
	December 31, 2017		Adjustments		January 1, 2018
Balance Sheet
Assets:
Prepaid expenses and other current assets	$	6,226	$	(464)	$	5,762
Other receivables	$	10,176	$	506	$	10,682
Total Assets	$	180,697	$	42	$	180,739
Equity:
Accumulated deficit	$	(237,459)	$	42	$	(237,417)
Total liabilities and stockholders' equity	$	180,697	$	42	$	180,739

The impact of adoption on the Company’s Consolidated Statement of Operations for the year ending December 31, 2018 was as follows (in thousands):


	Year Ended December 31, 2018
	As Reported		Adjustments		Balance without Adoption of Topic 606
Statement of Operations
Grant Revenues	$	11,268	$	346	$	11,614
Licensing and collaboration revenue	$	1,206	$	116	$	1,322
Research and Development	$	45,694	$	420	$	46,114
Net Loss	$	(53,595)	$	42	$	(53,553)

The impact of adoption on the Company’s Consolidated Statement of Cash Flows for the year ending December 31, 2018 was as follows (in thousands):


	Year Ended December 31, 2018
			Balance without
	As Reported	Adjustments	Adoption of Topic 606
Statement of Cash Flows
Net Loss	(53,595)	42	(53,553)
Changes in operating assets and liabilities
Other receivables	10,223	(492)	9,731
Accounts payable and accrued expenses	(13,029)	450	(12,579)
Net cash used in operating activities	(37,939)	—	(37,939)

Leases

12 Months Ended

Dec. 31, 2018

Leases [Abstract]

Leases

(a) Capital Leases

The following is an analysis of the leased property under capital leases by major class (in thousands):


	Asset Balances at December 31,
Class of property	2018		2017
Lab equipment	$	720	$	720
Leasehold improvements	27		27
Computer equipment	54		54
Total property under capital leases	801		801
Less accumulated depreciation and amortization	(703)		(652)
Capital leased assets, net	$	98	$	149

The depreciation and amortization reflected above has been recorded in both research and development and general administrative expense in the consolidated statements of operations.

We have no future minimum lease payments under capital leases as of December 31, 2018.

(b) Operating Leases

The Company has certain facility leases with non-cancellable terms ranging between one and three years, with certain renewal options. Lease expense is recognized on a straight-line basis. Rental expense for operating leases during the years ended December 31, 2018, 2017 and 2016, was $1.1 million, $1.2 million, and $1.7 million, respectively, including those with terms less than one year, and has been included in both research and development and general and administration in the consolidated statements of operations.

Future minimum lease payments under the noncancelable operating leases (with initial or remaining lease terms in excess of one year), with certain renewal options, as of December 31, 2018 are as follows (in thousands):


Year Ending December 31:
2019	$	1,105
2020	1,004
2021	923
2022	906
2023	909
Thereafter	6,570
Total	$	11,417

Leasehold improvements and equipment

12 Months Ended

Dec. 31, 2018

Property, Plant and Equipment [Abstract]

Leasehold improvements and equipment

Leasehold Improvements and EquipmentLeasehold improvements and equipment at December 31, 2018 and 2017 consisted of the following:


	Year Ended December 31,
	2018		2017
Leasehold improvements	$	5,300	$	5,310
Computer and office equipment	1,984		2,326
Lab and leased equipment	3,398		3,979
Contract manufacturing organization equipment	30		114
Assets not placed in service	—		—
Total leasehold improvements and equipment	10,712		11,729
Less accumulated depreciation and amortization	(6,985)		(6,638)
Total leasehold improvements and equipment, net	$	3,727	$	5,091

Long-Term Debt Conversion to Royalty Obligation	12 Months Ended
Long-Term Debt Conversion to Royalty Obligation	Dec. 31, 2018
Debt Disclosure [Abstract]
Long-Term Debt and Conversion to Royalty Obligation	Long-Term Debt and Conversion to Royalty Obligation March 2005 Iowa Department of Economic Development Loan In March 2005, the Company entered into a $6.0 million forgivable loan agreement with the Iowa Department of Economic Development, or the IDED. Under the agreement, in the absence of default, there were no principal or interest payments due until the completion date for the project. The balance outstanding under the loan agreement was $6.0 million as of December 31, 2011. This loan was converted into a royalty obligation under the terms of a settlement agreement entered into on March 26, 2012, or the IEDA Agreement, with the Iowa Economic Development Authority (the IEDA), as successor in interest to the IDED. March 2012 IEDA Royalty Obligation Under the terms of the IEDA Agreement the Company agreed to pay a 0.5% royalty on future product sales up to a cap of $6.8 million in exchange for IDED’s release of the Company's job creation and project expenditure obligations and their release of the security interest in substantially all of the Company's assets. As no payments are expected in the next 12 months, the entire accrued royalty obligation of $6.0 million is considered long-term as of December 31, 2018. 2009 and 2012 Iowa State University Research Park Notes In 2009, the Company executed a promissory note in favor of Iowa State University Research Park, or ISURP, in an original principal amount of $800,000, which is due in monthly installments through March, 2018. The note represents amounts owed by the Company to ISURP for certain improvements that were made to facilities the Company leases from ISURP. The principal and interest owed under the note is amortized over an eight-year period. Interest is payable monthly under this promissory note, initially at a rate of 3.0% per annum and increasing to 5.0% per annum after five years from the date the improvements were completed. ISURP may accelerate all amounts owed under the note upon an event of default, including the Company’s uncured material breach of the terms of the note or the lease or upon early termination of the lease. In the event of a default under the note, amounts owed under the note will bear interest at 8.0% per annum. The balance outstanding under the 2009 note was $0 and $29,000 at December 31, 2018 and December 31, 2017, respectively. In 2012, the Company executed a promissory note in favor of ISURP in an original principal amount of $456,000, which is due in monthly installments through September 2020. The note represents amounts owed by the Company to ISURP for certain additional improvements that were made to facilities the Company leases from ISURP. The principal and interest owed under the note is amortized over an eight-year period. Interest is payable monthly under this promissory note, initially at a rate of 3.0% per annum and increasing to 5.0% per annum after five years from the date the improvements were completed. ISURP may accelerate all amounts owed under the note upon an event of default, including the Company’s uncured material breach of the terms of the note or the lease or upon early termination of the lease. In the event of a default under the note, amounts owed under the note will bear interest at 8.0% per annum. The balance outstanding under the 2012 note was $111,000 and $169,000 at December 31, 2018 and December 31, 2017, respectively. March 2010 City of Ames Forgivable Loan In March 2010, the Company entered into a $400,000 forgivable loan agreement with the City of Ames, Iowa and the Ames Chamber of Commerce, jointly, as lenders. The project provided the Company with financial assistance to construct new facilities within the Ames city limits. In the absence of a default, there were no principal or interest payments due until March 10, 2016. The project called for the Company to create or retain at least 150 full-time positions located in Ames, Iowa by March 10, 2016. The agreement required the Company to enter into a five-year building lease with the option for extension for an additional five years of not less than 20,000 square feet within the corporate limits of the City of Ames by March 10, 2015, which requirement the Company met by the March 10, 2015 deadline. As of March 10, 2016, the Company had satisfactorily fulfilled all of the above terms of the loan agreement and the loan was forgiven. Accordingly, the entire amount of $397,000 was derecognized with a corresponding amount recorded in grant revenue for the year ended December 31, 2016.

License and Research Collaboration Agreements	12 Months Ended
License and Research Collaboration Agreements	Dec. 31, 2018
Revenue Recognition [Abstract]
License and Research Collaboration Agreements	License and Research Collaboration Agreements Genentech, a Member of the Roche Group In October 2014, the Company entered into a worldwide exclusive collaboration and license agreements with Genentech for the development and commercialization of NLG919, one of NewLink's clinical stage IDO pathway inhibitors and for a research collaboration for the discovery of next generation IDO/TDO compounds to be developed and commercialized under this agreement. Under the terms of the agreement, the Company received a nonrefundable upfront cash payment of $150.0 million from Genentech in 2014. On June 6, 2017, we received a formal notice of Genentech’s intent to terminate the Genentech Agreement with respect to NLG919. As part of the partial termination, worldwide rights to NLG919 reverted to us, and Genentech granted to us an exclusive, royalty-bearing license under certain Genentech intellectual property to develop and commercialize NLG919. If NLG919 is commercialized, we will be obligated to pay to Genentech royalties as a low single-digit percentage of net sales of NLG919. Additionally, on May 9, 2018 the Company received formal notice that Genentech would not continue the collaboration with respect to next generation IDO/TDO inhibitors identified through the research program. The Genentech Agreement terminated in its entirety on November 6, 2018. The Company was obligated to deliver multiple non-contingent deliverables related to the NLG919 upfront cash payment. These deliverables include the NLG919 development and commercialization license, research license, program materials and technology, clinical supply of NLG919 product, manufacturing technology, participation in a joint research committee, or JRC, and providing an alliance manager. The Company's obligations under the JRC ended November 2016. The NLG919 development and commercialization license and research license are separate deliverables, but without the ability to develop NLG919, the ability to perform research on the compound would not benefit Genentech. Therefore, the Company believes that the value of the development and commercialization license cannot be separated from the research license value and the two are valued together. The other deliverables qualify as separate units of accounting. The respective standalone value from each of these deliverables was determined by applying the best estimated selling price method and the revenue was allocated based on the relative selling price method with revenue recognition timing to be determined either by delivery or the provision of service. The estimated selling price determination required the use of significant estimates. To determine the stand-alone value of the license, we considered the negotiation discussions that led to the final terms of the agreement. The Company utilized historical cost plus an estimated gross margin to estimate the selling price for program materials and technology, manufacturing technology, clinical supply, participation in a JRC, and participation of an alliance manager. The program materials and technology, clinical supply of NLG919, participation in a JRC and participation of an alliance manager were delivered throughout the duration of the agreement. The license and manufacturing technology was delivered shortly after the effective date of the agreement. The Company recognized revenue under this agreement of $56,000 for the year ended December 31, 2018. This amount includes the recognition of $56,000 for providing an alliance manager to the collaboration. All deliverables identified within the collaboration and license agreement have been completed in their entirety and there is no deferred revenue as of December 31, 2018. The Company recognized revenue under this agreement of $335,000 for the year ended December 31, 2017. This amount includes the recognition of $335,000 for providing an alliance manager to the collaboration. Revenue of $56,000 was deferred as of December 31, 2017 for deliverables identified within the collaboration and license agreement that had not yet been completed in their entirety. The Company recognized revenue under this agreement of $2.7 million for the year ended December 31, 2016. This amount includes the recognition of $180,000 for participation in the JRC, and $670,000 for providing an alliance manager to the collaboration. Additionally, $1.9 million was recognized for amounts received as reimbursement for the Company's employees working on the project. Revenues of $391,000 remain deferred as of December 31, 2016 for deliverables identified within the collaboration and license agreement that have not yet been completed in their entirety. Merck Sharpe & Dohme Corp. In November 2014, the Company entered into a licensing and collaboration agreement with Merck to develop, manufacture and commercialize rVSV∆G-ZEBOV GP, an Ebola vaccine the Company licensed from the Public Health Agency of Canada, or PHAC. Under the terms of the agreement, the Company granted Merck an exclusive, royalty-bearing license to the rVSV∆G-ZEBOV GP and related technology. NewLink received a $30.0 million non-refundable, upfront payment in December 2014, and was also eligible for a one-time $20.0 million non-refundable milestone payment upon the initiation of the pivotal clinical trial using the current rVSV∆G-ZEBOV GP vaccine product as one arm of the trial. In February 2015, this milestone was achieved and the Company received the milestone payment. On December 5, 2017, the Merck Agreement was amended in connection with our entry into an Amended and Restated PHAC license on December 5, 2017 NewLink can receive escalating royalties on potential commercial sales by Merck of the current product candidate ranging from single-digit to double-digits on the rVSV∆G-ZEBOV GP license agreement product sales on increasing levels of annual net sales worldwide. Merck will lead the development of rVSV∆G-ZEBOV GP in order to create a marketable product safe for human use. The Company completed all deliverables under the Merck Agreement in their entirety during the year ended December 31, 2016. The Company recognized revenue under this agreement of $815,300 for the year ended December 31, 2016. This amount includes the recognition of $53,800 relating to the remaining deliverables and $761,500 for the reimbursement of costs associated with the Ebola clinical trials not reimbursed under the Company's government contracts. The Company is eligible to receive from Merck tiered royalty payments based on product sales, with royalty rates varying based on Merck sales of the current rVSV∆G-ZEBOV GP vaccine product and Merck sales of other products included within the Company’s patent rights. Royalties will be recognized when Merck results are reported and will be computed in accordance with contract terms.

Stockholders' Equity	12 Months Ended
Stockholders' Equity	Dec. 31, 2018
Stockholders' Equity Note [Abstract]
Stockholders' Equity	Stockholders' Equity Common Stock The holders of common stock are entitled to one vote per share on all matters to be voted upon by the Company stockholders. Subject to preferences applicable to outstanding preferred stock, the holders of common stock are entitled to receive ratably such dividends, if any, as may be declared from time to time by the Company's Board of Directors. In the event of liquidation, dissolution, or winding up of the Company, the holders of common stock are entitled to share ratably in all assets remaining after payment of liabilities subject to prior distribution rights of the preferred stock. Preferred Stock As of December 31, 2018 and 2017, the Company had no outstanding preferred stock. The Company's Board of Directors has the authority to issue up to 5,000,000 shares of preferred stock in one or more series and to fix the voting power and such designations, preferences, and rights of such series, subject to approval of outstanding preferred series shareholders.

Common Stock Equity Incentive Plans

12 Months Ended

Dec. 31, 2018

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Common Stock Equity Incentive Plan

Common Stock Equity Incentive PlansIn April 2000, the stockholders approved NewLink’s 2000 Equity Incentive Plan. as amended, or the 2000 Plan, and in July 2009, the stockholders approved NewLink’s 2009 Equity Incentive Plan, as amended, or the 2009 Plan. Following the

approval of the 2009 Plan, all options outstanding under the 2000 Plan were effectively included under the 2009 Plan. Under the provisions of the 2009 Plan, NewLink may grant the following types of common stock awards:

•Incentive Stock Options

•Nonstatutory Stock Options

•Restricted Stock Awards

•Stock Appreciation Rights

Awards under the 2009 Plan, as amended, may be made to officers, employees, members of the NewLink Board of Directors, advisors, and consultants to NewLink. As of December 31, 2018 there were 11,722,602 shares of common stock authorized for the 2009 Plan and 1,879,686 shares remained available for issuance. As of December 31, 2017 there were 10,238,220 shares of common stock authorized for issuance pursuant to the 2009 Plan and 1,195,358 shares remained available for issuance.

The following table summarizes the authorized increases of common stock under the 2009 Plan:


Date Authorized						Authorized Shares Added
May 15, 2010						1,238,095
January 7, 2011						714,286
January 1, 2013						838,375
January 1, 2014						1,066,340
January 1, 2015						1,119,255
January 1, 2016						1,152,565
January 1, 2017						1,166,546
January 1, 2018						1,484,382

Subsequent to year end, on January 1, 2019, an additional 1,490,048 shares of common stock were added to the shares reserved for future issuance under the 2009 plan. The increases in the authorized shares of common stock under the 2009 Plan in 2010 and 2011 were approved by the Company’s stockholders. The increases in the authorized shares of common stock under the 2009 Plan in 2012 through 2018 were made pursuant to an “evergreen provision,” in accordance with which, on January 1 of each year, from 2012 to (and including) 2019, a number of shares of common stock in an amount equal to 4% of the total number of shares of common stock outstanding on December 31 of the preceding calendar year, or such lesser amount of shares (or no shares) approved by the Company's Board of Directors, was added or will be added to the shares reserved under the 2009 Plan.

Under the terms of the Company's 2010 Non-Employee Directors’ Stock Option Plan, as amended, or the Directors’ Plan, which became effective on November 10, 2011, 238,095 shares of common stock were reserved for future issuance. On May 9, 2013, an additional 161,905 shares of common stock were added to the reserve. As of December 31, 2018, no shares are available for issuance under the Directors' Plan.

Under the terms of the Company's 2010 Employee Stock Purchase Plan, as amended, or the 2010 Purchase Plan, which became effective on November 10, 2011, 214,285 shares of common stock were reserved for future issuance. On May 9, 2013, an additional 185,715 shares of common stock were added to the reserve. As of December 31, 2018, 53,509 shares remained available for issuance under the plan. During the years ended December 31, 2018 and 2017, 48,487 and 70,787 shares of common stock, respectively, were purchased under the terms of the 2010 Purchase Plan.

Share-based Compensation

Share-based employee compensation expense for the years ended December 31, 2018, 2017 and 2016, was $17.1 million, $18.5 million, and $16.7 million, respectively, and is allocated between research and development and general and administrative expenses within the consolidated statements of operations. As of December 31, 2018, the total compensation cost related to unvested option awards not yet recognized was $8.3 million and the weighted average period over which it is expected to be recognized was 2.1 years. The Company recognized no income tax benefit in the consolidated statements of operations for stock-based compensation arrangements for the years ended December 31, 2018, 2017 and 2016, respectively.

Stock Options

The Company's Board of Directors determines the vesting period for each stock option award. Generally, stock options awarded to date under the 2009 Plan vest monthly or vest 25% on the first anniversary date of issuance with the remaining options vesting ratably over the next 36 months. The stock options may include provisions for early exercise of options. If any shares acquired are unvested, they are subject to repurchase at the Company’s discretion until they become vested.

The following table summarizes the stock option activity for the year ended December 31, 2018:


	Number of options	Weighted average exercise price		Weighted average remaining contractual term (years)
Outstanding at beginning of period	7,206,884	$	13.73
Options granted	1,657,523	6.85
Options exercised	(38,074)	3.78
Options forfeited	(459,062)	12.39
Options expired	(387,627)	25.30
Outstanding at end of period	7,979,644	11.86		4.5
Options exercisable at end of period	6,262,449	$	12.56	3.3

Based on the December 31, 2018 price of $1.52 per share, the intrinsic value of stock options outstanding at December 31, 2018, was $2,357, all of which related to stock options that were vested at that date.

The following table summarizes options that were granted during the years ended December 31, 2018, 2017 and 2016, and the range of assumptions used to estimate the fair value of those stock options using a Black-Scholes valuation model:


	Years Ended December 31,
	2018	2017	2016
Number of options granted	1,657,523	1,526,787	1,346,758
Risk-free interest rate	2.61%-3.02%	1.91%-2.22%	1.19%-1.97%
Expected dividend yield	—	—	—
Expected volatility	76.2%-79.3%	68.9%-76.9%	67.1%-69.8%
Expected term (in years)	4.0-7.9	1.2-7.8	5.9-7.4
Weighted average grant-date fair value per share	$4.84	$7.72	$11.91

The following table summarizes the intrinsic value of options exercised and the fair value of awards vested during the years ended December 31, 2018, 2017 and 2016:

Years Ended December 31,

2018

2017

2016

Intrinsic value of options exercised

$83,000

$1.0 million

$1.1 million

Fair value of awards vested

$13.0 million

$15.0 million

$15.1 million

Restricted Stock

Restricted stock is common stock that is subject to restrictions, including risks of forfeiture, determined by the plan committee of the Board of Directors in its sole discretion, for so long as such common stock remains subject to any such restrictions. A holder of restricted stock has all rights of a stockholder with respect to such stock, including the right to vote and to receive dividends thereon, except as otherwise provided in the award agreement relating to such award. Restricted stock awards are equity classified within the consolidated balance sheets. The fair value of each restricted stock grant is estimated on the date of grant using the closing price of the Company's Common Stock on The NASDAQ Global Market on the date of grant.

During the year ended December 31, 2018 and 2017, there were no shares of restricted stock granted. Compensation expense is determined for the issuance of restricted stock by amortizing using either a straight-line basis or the accelerated attribution method over the requisite service period, or the vesting period, the aggregate fair value of the restricted stock awarded based on the closing price of the Company's common stock on the date of grant.

A summary of the Company's unvested restricted stock at December 31, 2018 and changes during the year ended December 31, 2018 is as follows:


	Restricted Stock	Weighted Average Grant Date Fair Value
Unvested at beginning of period	168,221	$	35.82
Granted	—	—
Vested	(88,864)	33.98
Forfeited/cancelled	(10,772)	38.63
Unvested at end of period	68,585	$	37.75

As of December 31, 2018, the total remaining unrecognized compensation cost related to issuances of restricted stock was approximately $1.0 million and is expected to be recognized over a weighted-average period of 0.9 years. The fair value of restricted stock awards vested during the year ended December 31, 2018 was $673,508.

The Company does not have a formal policy regarding the source of shares issued upon exercise of stock options or issuance of restricted stock. The Company expects shares issued to be issued from treasury shares or new shares.

Income Taxes

12 Months Ended

Dec. 31, 2018

Income Tax Disclosure [Abstract]

Income Taxes

U.S. Tax Reform

On December 22, 2017, the U.S. government enacted comprehensive tax legislation commonly referred to as the Tax Cuts and Jobs Act (the "Tax Act"). The Tax Act makes broad and complex changes to the U.S. tax code that affect fiscal 2017 and 2018. The Tax Act also makes a number of changes to U.S. federal income tax laws that affect 2018 and later years, including, but not limited to, a reduction of the U.S. federal corporate income tax rate from 35% to 21%, the repeal of the corporate alternative minimum tax ("AMT"), the limitation on net operating loss deductions to 80 percent of taxable income for losses beginning after December 31, 2017 and the repeal of the current two-year carryback provision for net operating losses arising after 2017.

In connection with its analysis of the impact of the Tax Act, the Company recorded a net tax benefit of $140,000 in 2017 which is for the release of the valuation allowance that had previously been recorded to offset the AMT deferred income tax benefit and classified this amount as a noncurrent income tax receivable. The Tax Act provides that AMT credit carryovers are partially refundable beginning in 2018 as an offset to a tax liability. The Company expects the amount to be fully refunded by 2021. The Tax Act had no other material impacts to the consolidated financial statements upon enactment.

Income tax benefit (expense) consists of (in thousands):


	Current		Deferred		Total
Year Ended December 31, 2018:
U.S. federal	$	—	$	—	$	—
State and local	6,968		—		6,968
	$	6,968	$	—	$	6,968

Year Ended December 31, 2017:
U.S. federal	$	332	$	140	$	472
State and local	87		—		87
	$	419	$	140	$	559

Year Ended December 31, 2016:
U.S. federal	$	6,469	$	—	$	6,469
State and local	(1,113)		—		(1,113)
	$	5,356	$	—	$	5,356

The tax effects of temporary differences that give rise to significant portions of deferred tax assets and the deferred tax liability at December 31, 2018 and 2017 are presented below (in thousands):


	Year Ended December 31,
	2018		2017
Deferred tax assets:
Net operating loss carryforwards	$	18,165	$	10,622
Federal research and development tax credits	28,283		26,327
Share-based compensation	14,150		11,780
Deferred rent	300		327
Accrued compensation	680		789
Unearned revenue	—		17
Charitable contributions	15		39
Leasehold improvements and equipment	417		297
Gross deferred tax assets	62,010		50,198
Less valuation allowance	(62,010)		(50,198)
Total deferred tax assets	—		—

The valuation allowance for deferred tax assets as of December 31, 2018 and 2017 was $62.0 million and $50.2 million, respectively. The net change in the total valuation allowance for the years ended December 31, 2018 and 2017 was an increase of $11.8 million and of $15.1 million, respectively. In assessing the realizability of deferred tax assets, management considers whether it is more likely than not that some portion or all of the deferred tax assets will not be realized. The ultimate realization of deferred tax assets is dependent upon the generation of future taxable income during the periods in which those temporary differences become deductible. Management considers the scheduled reversal of deferred tax liabilities, projected taxable income, and tax planning strategies in making this assessment. Valuation allowances have been established for the entire amount of the net deferred tax assets as of December 31, 2018 and 2017, due to the uncertainty of future recoverability.

Federal operating loss carryforwards as of December 31, 2018 of approximately $74.5 million and federal research credit carryforwards of approximately $28.3 million expire at various dates from 2026 through 2035. Sections 382 and 383 of the Internal Revenue Code limit a corporation’s ability to utilize its net operating loss carryforwards and certain other tax attributes (including research credits) to offset any future taxable income or tax if the corporation experiences a cumulative ownership change of more than 50% over any rolling three-year period. State net operating loss carryforwards (and certain other tax attributes) may be similarly limited. An ownership change can therefore result in significantly greater tax liabilities than a corporation would incur in the absence of such a change and any increased liabilities could adversely affect the corporation’s business, results of operations, financial condition and cash flow.

Based on analysis from its inception through December 31, 2017, the Company experienced Section 382 ownership changes in September 2001 and March 2003 and one of its subsidiaries experienced Section 382 ownership changes in January 2006 and January 2011 and the reported deferred tax assets reflect these expected limitations. These ownership changes limited the Company's ability to utilize federal net operating loss carryforwards (and certain other tax attributes) that accrued prior to the respective ownership changes of the Company and one of its subsidiaries. Additional ownership changes may occur in the future as a result of events over which the Company will have little or no control, including purchases and sales of the Company’s equity by our 5% stockholders, the emergence of new 5% stockholders, additional equity offerings or redemptions of the Company’s stock or certain changes in the ownership of any of the Company’s 5% stockholders.

A reconciliation of income taxes at the statutory federal income tax rate to net income tax benefit included in the accompanying statements of operations is set forth in the following table:


	Year ended December 31,
	2018		2017		2016
U.S. federal income tax benefit at the statutory rate	(21.00)	%	(35.00)	%	(35.00)	%
State income taxes, net of federal taxes	(10.07)		(.03)		.88
Loss in foreign subsidiary	1.20		7.36		15.88
Valuation allowance, including impact of tax reform	18.20		24.10		12.07
Other	.16		2.80		.25
Total	(11.51)	%	(.77)	%	(5.92)	%

The loss in foreign subsidiary reconciling item in the above table is the tax effect of intercompany research and development expenses which are not deductible on the Company's consolidated federal income tax return. The state income tax benefit item in the above table is the result of the Company filing amendments in 2018 for certain states for 2014 and 2015 and receiving a refund in 2018.

The Company accounts for the effect of any uncertain tax positions based on a more likely than not threshold to the recognition of the tax positions being sustained based on the technical merits of the position under scrutiny by the applicable taxing authority. If a tax position or positions are deemed to result in uncertainties of those positions, the unrecognized tax position is estimated based on a cumulative probability assessment that aggregates the estimated tax liability for all uncertain tax positions. Interest and penalties assessed, if any, are accrued and recorded in either interest expense or miscellaneous expense, respectively in the consolidated statement of operations. During the year ended December 31, 2018, the Company recorded interest and penalties relating to its uncertain tax position of $82,000 in its consolidated statement of operations in interest expense and other expenses. $335,000 and no interest or penalties were recorded for the years ended December 31, 2017 and 2016, respectively. The liability for uncertain tax benefits consists of estimated federal and state income tax liabilities in years for which the statute of limitations is open. Open years range from 2014 through 2017.

The changes in the Company's uncertain income tax positions for the year ended December 31, 2018 consisted of the following (in thousands):



	December 31, 2018
Beginning Balance - uncertain tax positions	$	653
Increases for tax positions related to current year	—
Decreases due to settlements with taxing authorities	—
Reductions due to lapsed statute of limitations	—
Ending Balance - uncertain tax positions	$	653

The Company does not anticipate the liability for uncertain tax positions as of December 31, 2018 to significantly change in the next 12 months.

Loss Per Share

12 Months Ended

Dec. 31, 2018

Earnings Per Share [Abstract]

Loss Per Share

The following table presents the calculations of loss per share:


	Years Ended December 31,
	2018		2017		2016
Historical net loss per share
Numerator
Net loss attributable to common stockholders	$	(53,595)	$	(71,951)	$	(85,155)

Denominator
Basic and diluted weighted-average shares outstanding	37,191,262		31,304,309		28,979,327



Basic and diluted loss per share	$	(1.44)	$	(2.30)	$	(2.94)

All common stock equivalents are excluded from the computation of diluted loss per share during periods in which losses are reported since the result would be anti-dilutive. For December 31, 2018, anti-dilutive stock options and restricted stock awards excluded from our calculation totaled 7,979,644 and 68,585, respectively. For December 31, 2017, anti-dilutive stock options and restricted stock awards excluded from our calculation totaled 7,206,884 and 168,221.

Licensing Agreements

12 Months Ended

Dec. 31, 2018

Licensing Agreements [Abstract]

Licensing Agreements

The Company is a party to a number of licensing agreements with respect to certain of the technologies that underlie its intellectual property. These agreements typically provide that the Company has exclusive rights to the use and sublicensing of the technologies in question for the duration of the intellectual property patent protection in question, subject to the Company meeting its financial and other contractual obligations under the agreements. The Company recognizes expense under its licensing agreements in the period the obligation is incurred. These agreements typically provide for a license fee based on a percent of sales and annual minimum royalties. For additional information regarding how the Company records payments under these agreements, see Note 2 above. The Company has incurred expense of approximately $32,000, $1.4 million, and $2.0 million, under all of the in-licensing agreements for the years ended December 31, 2018, 2017, and 2016, respectively, which is recorded as a component of general and administrative expenses.

Under certain license agreements the Company is obligated to make potential milestone payments as listed in the following table. In addition to the milestone payments, each license is paid as a low single-digit percentage of net sales of the licensed product, subject to annual minimum royalties. These obligations are contingent upon achieving the applicable milestone event, the timing of which cannot presently be determined. The milestone payments and royalty payments are in place through at least the expiration of certain of the Company's patents, which is currently 2029 and beyond.


Licensor						Aggregate potential milestone payments






Augusta University Research Institute under AURI IDO						$2.8 million per licensed product

Public Health Agency of Canada						$250,000

Employee Benefit Plans	12 Months Ended
Employee Benefit Plans	Dec. 31, 2018
Retirement Benefits [Abstract]
Employee Benefit Plans	Employee Benefit Plans The Company sponsors a 401(k) plan, which includes a defined contribution feature. The Company's defined contribution was $261,000, $361,000, $482,000 for the years ended December 31, 2018, 2017 and 2016, respectively. The Company made discretionary contributions to the plan of $303,000, $401,000, and $446,000 for the years ended December 31, 2018, 2017 and 2016, respectively. The Company has approved employment agreements for certain executives, dated October 29, 2010, as amended January 4, 2016, that provide for the payment of 6 to 24 months of base salary, bonus, and group health insurance premiums plus accrued obligations upon termination of the executive in certain circumstances. The agreements include provisions to accelerate the vesting of stock options subject to certain events including those related to a change in control. The Company entered into the January 2016 amendments to the foregoing agreements, upon recommendation by the Compensation Committee of the Board of Directors, to align the terms of certain termination benefits with termination terms for executive officers at similarly situated companies to the Company.

Restructuring Charges

12 Months Ended

Dec. 31, 2018

Restructuring and Related Activities [Abstract]

Restructuring Charges

The Company records liabilities for costs associated with exit or disposal activities in the period in which the liability is incurred. Employee severance costs are accrued when the restructuring actions are probable and estimable. Costs for one-time termination benefits in which the employee is required to render service until termination in order to receive the benefits are recognized ratably over the future service period. The Company also records costs incurred with contract terminations associated with restructuring activities.

In July 2018, the Company completed an organizational review of its clinical programs and reduce its headcount by approximately 30% as compared to June 30, 2018 and made several changes to senior leadership effective July 26, 2018 in order to conserve resources to further advance its clinical development programs. Restructuring expenses of $1.3 million were recorded during 2018, of which $800,000 is included within general and administrative expenses and $500,000 is included within the research and development expenses in the condensed consolidated statement of operations.

In July 2017, the Company undertook an organizational realignment to refocus its clinical development efforts and align the Company's resources to focus on the Company's highest value opportunities. The Company's restructuring activities included a reduction of its workforce by approximately 50%, which consisted primarily of clinical and research and development staff, as well as stopping additional research on the Zika virus. Restructuring charges recorded during 2017 included $1.7 million, of which $1.1 million is included within general and administrative expenses and $600,000 is included within research and development expenses in the consolidated statement of operations. The charges include employee severance costs of one-time employee termination benefits and certain expenses related to contractual termination benefits for employees with pre-existing severance arrangements.

The following table shows the amount accrued for restructuring activities which is recorded within Accrued Expenses in the consolidated balance sheet (in thousands):


	Employee Severance Cost		Total
Balance as of December 31, 2017	$	207	$	207
Expensed	1,323		1,323
Cash Payments	881		881
Adjustments	—		—
Balance as of December 31, 2018	$	649	$	649

Commitments and Contingencies	12 Months Ended
Commitments and Contingencies	Dec. 31, 2018
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies From time to time, claims are asserted against the Company arising in the ordinary course of business. In the opinion of management, liabilities, if any, arising from existing claims are not expected to have a material effect on the Company's earnings, financial position, or liquidity. On or about May 12, 2016, Trevor Abramson filed a putative securities class action lawsuit in the United States District Court for the Southern District of New York, or the Court, captioned Abramson v. NewLink Genetics Corp., et al., Case 1:16-cv-3545, or the Securities Action. Subsequently, the Court appointed Michael and Kelly Nguyen as lead plaintiffs and approved their selection of Kahn, Swick & Foti, LLC as lead counsel in the Securities Action. On October 31, 2016, the lead plaintiffs filed an amended complaint asserting claims under the federal securities laws against the Company, the Company’s Chief Executive Officer Charles J. Link, Jr., and the Company’s Chief Medical Officer and President Nicholas Vahanian, or collectively, the Defendants. The amended complaint alleges the Defendants made material false and/or misleading statements that caused losses to the Company’s investors. In particular, the lead plaintiffs allege that the Defendants made material misstatements or omissions related to the Phase 2 and 3 trials and efficacy of the product candidate algenpantucel-L. The lead plaintiffs do not quantify any alleged damages in the amended complaint but, in addition to attorneys’ fees and costs, they sought to recover damages on behalf of themselves and other persons who purchased or otherwise acquired the Company’s stock during the putative class period of September 17, 2013 through May 9, 2016, inclusive, at allegedly inflated prices and purportedly suffered financial harm as a result. The Defendants filed a motion to dismiss the amended complaint on July 14, 2017. The lead plaintiffs filed an opposition to the motion to dismiss on September 12, 2017. The Defendants filed a reply in support of the motion to dismiss on September 26, 2017. Oral argument was held on October 19, 2017, after which the Court reserved decision.On March 29, 2018, the Court dismissed the amended complaint for failure to state a claim, without prejudice, and gave the lead plaintiffs until May 4, 2018 to file any amended complaint attempting to remedy the defects in their claims. On May 4, 2018, the lead plaintiffs filed a second amended complaint asserting claims under the federal securities laws against the Defendants. Like the first amended complaint, the second amended complaint alleges that the Defendants made material false and/or misleading statements or omissions relating to the Phase 2 and 3 trials and efficacy of the product candidate algenpantucel-L that caused losses to the Company’s investors. The lead plaintiffs do not quantify any alleged damages in the second amended complaint but, in addition to attorneys’ fees and costs, they sought to recover damages on behalf of themselves and other persons who purchased or otherwise acquired the Company’s stock during the putative class period of September 17, 2013 through May 9, 2016, inclusive, at allegedly inflated prices and purportedly suffered financial harm as a result. The Defendants filed a motion to dismiss the second amended complaint on July 31, 2018. The lead plaintiffs filed an opposition to the motion to dismiss the second amended complaint on September 14, 2018. The Defendants filed a reply in support of the motion to dismiss the second amended complaint on October 9, 2018. Oral argument was held on October 19, 2018, after which the Court reserved decision. On February 13, 2019, the Court dismissed the second amended complaint for failure to state a claim, with prejudice, and closed the case, In the event that the plaintiffs in the Securities Action attempt to continue to pursue their claims, the Company intends to continue defending the Securities Action vigorously. On or about April 26, 2017, Ronald Morrow filed a shareholder derivative lawsuit on behalf of the Company in the United States District Court for the Southern District of New York, or the Court, against the Company’s Chief Executive Officer Charles J. Link, Jr., the Company’s Chief Medical Officer and President Nicholas Vahanian, and Company directors Thomas A. Raffin, Joseph Saluri, Ernest J. Talarico, III, Paul R. Edick, Paolo Pucci, and Lota S. Zoth, or collectively, the Morrow Defendants, captioned Morrow v. Link., et al., Case 1:17-cv-03039, or the Morrow Action. The complaint alleges that the Morrow Defendants caused the Company to issue false statements in its 2016 proxy statement regarding risk management and compensation matters in violation of federal securities law. The complaint also asserts state law claims against the Morrow Defendants for breaches of fiduciary duties, unjust enrichment, abuse of control, insider trading, gross mismanagement, and corporate waste, alleging that the Morrow Defendants made material misstatements or omissions related to the Phase 2 and 3 trials and efficacy of the product candidate algenpantucel-L, awarded themselves excessive compensation, engaged in illegal insider trading, and grossly mismanaged the Company. The plaintiff does not quantify any alleged damages in the complaint but seeks restitution for damages to the Company, attorneys’ fees, costs, and expenses, as well as an order directing that proposals for strengthening board oversight be put to a vote of the Company’s shareholders. The language for such proposals is not specified in the complaint. The plaintiff also contemporaneously filed a statement of relatedness, informing the Court that the Morrow Action is related to Abramson v. NewLink Genetics Corp., et al., Case 1:16-cv-3545. On May 19, 2017, the plaintiff dismissed the Morrow Action without prejudice. Also on May 19, 2017, plaintiffs’ counsel in the Morrow Action filed a new shareholder derivative complaint that is substantively identical to the Morrow Action, except that the plaintiff is Rickey Ely. The latter action is captioned Ely v. Link, et al., Case 17-cv-3799, or the Ely Action. By agreement of the parties and order dated June 26, 2017, the Court temporarily stayed the Ely Action until the Securities Action is dismissed or otherwise finally resolved. Under the terms of the stay, the plaintiff in the Ely Action has until March 15, 2019 (30 days after dismissal of the Securities Action to file an amended derivative complaint or rest upon the current derivative complaint. The Company disputes the claims in the Ely Action and intends to defend against them vigorously.

Quarterly Financial Information (Unaudited)

12 Months Ended

Dec. 31, 2018

Quarterly Financial Information Disclosure [Abstract]

Quarterly Financial Information (Unaudited)


	First		Second		Third		Fourth
	(In thousands, except per share data)
Year Ended December 31, 2018
Grant and licensing revenue	$	9,900	$	2,252	$	120	$	202
Loss from operations	(18,706)		(17,748)		(15,038)		(10,946)
Net loss	(18,310)		(17,313)		(7,403)		(10,569)
Basic and diluted loss per share	$	(.49)	$	(.47)	$	(.20)	$	(.28)

Year Ended December 31, 2017
Grant and licensing revenue	$	2,761	$	10,370	$	5,482	$	10,098
Loss from operations	(21,198)		(16,727)		(20,905)		(14,051)
Net loss	(20,913)		(16,726)		(20,626)		(13,686)
Basic and diluted loss per share	$	(.72)	$	(.57)	$	(.69)	$	(.37)

Significant Accounting Policies (Policies)	12 Months Ended
Significant Accounting Policies (Policies)	Dec. 31, 2018
Accounting Policies [Abstract]
Use of Estimates	Use of Estimates The preparation of consolidated financial statements in conformity with U.S. generally accepted accounting principles, or U.S. GAAP, requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the consolidated financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates.
Principles of Consolidation	Principles of Consolidation The consolidated financial statements include the financial statements of NewLink and its wholly owned subsidiaries. All intercompany balances and transactions have been eliminated in consolidation.
Cash and Cash Equivalents	Cash and Cash EquivalentsFor the purposes of the consolidated statements of cash flows, the Company considers all highly liquid debt instruments with an original maturity of three months or less to be cash equivalents.
Leasehold Improvements and Equipment, and Deferred Rent	Leasehold Improvements and Equipment, and Deferred Rent Leasehold improvements and equipment are capitalized as the Company believes they have alternative future uses and are stated at cost. Equipment under capital leases is stated at the present value of future minimum lease payments. Depreciation on all leasehold improvements and equipment is calculated on the straight-line method over the shorter of the lease term or estimated useful life of the asset. Computer equipment has useful lives of three to five years, lab equipment has a useful life of five years and contract manufacturing organization equipment has a useful life of five years. Deferred rent reflects improvement allowances from the Company's lessors deferred to be recognized as part of lease expense over the remaining term of the lease, which is recognized on a straight-line basis.
Impairment of Long-Lived Assets	Impairment of Long-Lived Assets Long-lived assets are reviewed for impairment whenever changes in circumstances indicate that the carrying amount of an asset may not be recoverable. Recoverability of assets to be held and used is measured by a comparison of the carrying amount of an asset group to future net undiscounted cash flows expected to be generated by the asset group, primarily relating to proceeds for selling the assets. If such assets are considered to be impaired, the impairment to be recognized is measured at the amount by which the carrying amount of the assets exceeds the fair value of the assets. Assets to be disposed of are reported at the lower of the carrying amount or fair value less costs to sell.
Revenue Recognition	Revenue Recognition Revenues are recognized under Topic 606 when control of the promised goods or services is transferred to the Company's customers, in an amount that reflects the consideration the Company expects to be entitled to in exchange for those goods or services. The Company receives payments from government entities under its grants and contracts with the Department of Defense and the United States Department of Health and Human Services, or HHS. These agreements provide the Company cost reimbursement plus a percentage for certain types of expenditures in return for research and development activities over a contractually defined period. Grant revenues are recognized over time and measured using the input method. The Company uses labor costs and subcontractor fees as inputs to measure progress towards satisfying its performance obligations under these agreements. This is the most faithful depiction of the transfer of goods and services to the government entities due to the government entities’ control over the research and development activities. Under this method, the Company recognizes revenue generally in the period during which the related costs are incurred, in an amount that reflects the consideration the Company expects to be entitled to in exchange for those goods or services. During the years ended December 31, 2018, 2017, and 2016, the Company has earned $11.3 million, $28.3 million, and $32.2 million in grant revenue, respectively. The Company had $309,000 and $9.3 million of receivables from the government contracts recorded in other receivables and $0 and $465,000 of unbilled expenses relating to the government contracts recorded in prepaid expenses and other assets on the balance sheet as of December 31, 2018 and 2017, respectively. The Company had $54,000 and $1.8 million of accrued expenses for subcontractor fees and $161,000 and $4.9 million of subcontractor fees in accounts payable for amounts incurred under the government contracts as of December 31, 2018 and 2017, respectively.
Expenses Accrued Under Contractual Arrangements with Third Parties; Accrued Clinical Expenses	Expenses Accrued Under Contractual Arrangements with Third Parties; Accrued Clinical Expenses The Company estimates its accrued expenses through a process of reviewing open contracts and purchase orders, communicating with personnel to identify services that have been performed and estimating the level of service performed and the associated cost incurred for the service that may not be invoiced from the provider. The estimates of accrued expenses as of each balance sheet date are based on facts and circumstances known at that time. Such estimates are periodically confirmed with the service providers to verify accuracy. The Company bases its expenses related to clinical trials on estimates of the services received and efforts expended pursuant to contracts with multiple research institutions and contract research organizations that conduct and manage clinical trials on behalf of the Company. Invoicing from third-party contractors for services performed can lag several months. The Company accrues the costs of services rendered in connection with third-party contractor activities based on its estimate of management fees, site management and monitoring costs and data management costs as contracted. Differences between actual clinical trial costs and estimated clinical trial costs are adjusted for in the period in which they become known through operations.
Research and Development	Research and Development Research and development costs are expensed as incurred. Research and development expenses consist primarily of employee-related expenses, which include salaries, bonuses, benefits and share-based compensation; manufacturing-related costs; clinical trial expenses which include expenses incurred under agreements with contract research organizations, investigative sites and consultants that conduct our clinical trials; facilities, depreciation of fixed assets and other allocated expenses, which include direct and allocated expenses for rent and maintenance of research facilities and equipment; license fees for and milestone payments related to in-licensed products and technology; and costs associated with non-clinical activities and regulatory approvals.
Patents	Patents The Company generally applies for patent protection on processes and products. Patent application costs are expensed as incurred as a component of general and administrative expense, as recoverability of such expenditures is uncertain.
Income Taxes	Income Taxes Income taxes are accounted for under the asset and liability method. Deferred tax assets and liabilities are recognized for the estimated future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases and operating loss and tax credit carryforwards. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in operating results in the period that includes the enactment date. Management assesses the realizability of deferred tax assets and records a valuation allowance if it is more likely than not that all or a portion of the deferred tax assets will not be realized. The Company accounts for the effect of any uncertain tax positions based on a more likely than not threshold to the recognition of the tax positions being sustained based on the technical merits of the position under scrutiny by the applicable taxing authority. If a tax position or positions are deemed to result in uncertainties of those positions, the unrecognized tax position is estimated based on a cumulative probability assessment that aggregates the estimated tax liability for all uncertain tax positions. Interest and penalties assessed, if any, are recorded in its consolidated statement of operations in interest expense and other expenses.
Share-Based Compensation	Share-Based Compensation The Company is required to estimate the grant-date fair value of share-based payment transactions with employees which include stock options, restricted stock units (RSUs) and performance shares (PSUs) and recognizes the compensation cost over the requisite service period based on the estimated fair values as well as expected forfeiture rates. The Company estimates the fair value of each award granted using the Black-Scholes option pricing model. The Black-Scholes model requires the input of assumptions, including the expected stock price volatility, the calculation of expected term and the fair value of the underlying common stock on the date of grant, among other inputs. The Company calculates the fair value of the award on the grant date, which is the date the award is authorized by the Board of Directors or Chief Executive Officer and the employee has an understanding of the terms of the award. Generally, the Company has issued employee awards that vest either monthly or 25% vest on the first anniversary date of issuance with the remaining options vesting ratably over the next 36 months. The Company records compensation cost on a straight-line basis over the vesting period. The fair value of RSUs that are subject to cliff vesting are recognized as compensation expense over the requisite service period using the straight line attribution method, and the fair value of RSUs that are subject to graded vesting are recognized as compensation expense over the requisite service period using the accelerated attribution method. The fair value of PSUs are recognized as compensation expense beginning at the time in which the performance conditions are deemed probable of achievement, over the remaining requisite service period. The Company has issued awards to nonemployee consultants and advisers. All grants to nonemployees are valued using the same fair value method that we use for grants to employees. The compensation cost on these awards is measured each period until vesting, and is recognized through the earlier of the vesting of the award or completion of services by the nonemployee. Following is a description of the inputs for the Black-Scholes model: Exercise Price The Company uses the quoted market price as listed on the public exchange on the date of grant. If Incentive Stock Options are granted to a 10% stockholder in the Company, the exercise price shall not be less than 110% of the common stock’s fair market value on the date of grant. Expected Term (in Years) The expected term of a stock option is the period of time for which the option is expected to be outstanding. The Company uses historical exercise and option expiration data to estimate the expected term for the Black-Scholes grant-date valuation. Risk-Free Interest Rate The Company uses the average yield on current U.S. Treasury instruments with terms that approximate the expected term of the stock options being valued. Expected Dividend Yield The expected dividend yield for all of the Company’s stock option grants is 0%, as the Company has not declared a cash dividend since inception and has no plans to declare a dividend. Expected Volatility The Company uses its historical stock price volatility. The volatility is calculated over a period of time commensurate with the expected term for the options granted. Forfeitures The share-based compensation expense has been reduced for estimated forfeitures. The estimated forfeiture rate is based on historical experience of the Company’s option plan, which the Company expects to continue at the current level, and any adjustments in the forfeiture rate in the future will result in a cumulative adjustment in the period that this estimate is changed. Ultimately, the total compensation expense recognized for any given stock-based award over its vesting period will only be for those shares that actually vest.
Segments	Segments The Company operates in one segment. The Company conducts research and development activities based from facilities located in Ames, Iowa and has corporate headquarters in Ames, Iowa and Austin, Texas. The Company conducts preclinical and clinical research in the biopharmaceutical industry. The chief operating decision maker uses cash flow as the primary measure to manage the business and management does not segment its business for internal reporting or decision-making.
Financial Instruments	Financial Instruments and Concentrations of Credit Risk The fair values of cash and cash equivalents, receivables and accounts payable, which are recorded at cost, approximate fair value based on the short-term nature of these financial instruments. The fair value of notes payable and capital lease obligations was $104,000 and $271,000 as of December 31, 2018 and 2017, respectively, and was determined using Level 2 inputs (computed in accordance with ASC 820). The Company is unable to estimate the fair value of the royalty obligation based on future product sales as the timing of payments, if any, is uncertain.
Concentrations of Credit Risk	Financial instruments that potentially subject the Company to concentrations of credit risk consist primarily of cash and cash equivalents. Cash and cash equivalents are held by financial institutions and are federally insured up to certain limits. At times, the Company’s cash and cash equivalents balance exceeds the federally insured limits. To limit the credit risk, the Company invests its excess cash primarily in high quality securities such as money market funds.
Earnings Per Share	Earnings per share (EPS)The Company computes basic EPS attributable to the Company's common stockholders by dividing net income (loss) attributable to the Company by our weighted-average common shares outstanding during the period. Diluted EPS reflects the potential dilution beyond shares for basic EPS that could occur if securities or other contracts to issue common stock were exercised, converted into common stock, or resulted in the issuance of common stock that would have shared in our earnings. The Company computes basic and diluted EPS using net income (loss) attributable to the Company's common stockholders, and its actual weighted-average shares.
Recently Adopted Accounting Pronouncements and Recent Accounting Pronouncements	Recently Adopted Accounting Pronouncements On May 28, 2014, the FASB issued ASU No. 2014-09 (Topic 606), Revenue from Contracts with Customers. Topic 606 supersedes the revenue recognition requirements in Topic 605 “Revenue Recognition” (Topic 605), and requires entities to recognize revenue when control of the promised goods or services is transferred to customers at an amount that reflects the consideration to which the entity expects to be entitled to in exchange for those goods or services. The Company adopted Topic 606 as of January 1, 2018, and as a result, changed its accounting policy for revenue recognition, as discussed in Note 3. Recent Accounting Pronouncements In February 2016, the FASB issued ASU No. 2016-02 (Topic 842), Leases, to improve financial reporting for leasing transactions. The Company will adopt the standard on January 1, 2019 using the modified retrospective method, as required, applying the new standard to all leases existing as of the date of initial application. The Company has elected that the date of initial application will be the effective date, or January 1, 2019. Consequently, financial information will not be updated and the disclosures required under the new standard will not be provided for dates and periods before January 1, 2019. The new standard provides a number of optional practical expedients in transition. The Company expects to elect the ‘package of practical expedients’, which permits the Company not to reassess under the new standard its prior conclusions about lease identification, lease classification and initial direct costs. The Company does not expect to elect the use-of-hindsight or the practical expedient pertaining to land easements; the latter not being applicable to the Company. The Company expects that this standard will have a material effect on its consolidated balance sheet due to the recognition of right-of-use assets and lease liabilities. While the Company continues to assess all of the effects of adoption, the Company expects it to primarily relate to the operating leases for office and laboratory space noted in "Part I. Item 2. Properties" of this Annual Report on Form 10-K, for which the Company will record a lease liability and corresponding right-of-use asset upon adoption. The lease liability will equal the present value of unpaid minimum lease payments for operating leases that exist as of the date of initial application of the new standard. Future undiscounted obligations related to facility leases in effect as of the date of initial application of the new standard are included in the table of future minimum lease payments disclosed in Note 4, and aggregate to $11.4 million.

Revenues (Tables)

12 Months Ended

Dec. 31, 2018

Revenue from Contract with Customer [Abstract]

New Accounting Pronouncements and Changes in Accounting Principles

As a result of applying the modified retrospective method to adopt the new revenue guidance, the following adjustments were made to accounts on the Consolidated Balance Sheet as of January 1, 2018 (in thousands):


	As Reported				Adjusted
	December 31, 2017		Adjustments		January 1, 2018
Balance Sheet
Assets:
Prepaid expenses and other current assets	$	6,226	$	(464)	$	5,762
Other receivables	$	10,176	$	506	$	10,682
Total Assets	$	180,697	$	42	$	180,739
Equity:
Accumulated deficit	$	(237,459)	$	42	$	(237,417)
Total liabilities and stockholders' equity	$	180,697	$	42	$	180,739

The impact of adoption on the Company’s Consolidated Statement of Operations for the year ending December 31, 2018 was as follows (in thousands):


	Year Ended December 31, 2018
	As Reported		Adjustments		Balance without Adoption of Topic 606
Statement of Operations
Grant Revenues	$	11,268	$	346	$	11,614
Licensing and collaboration revenue	$	1,206	$	116	$	1,322
Research and Development	$	45,694	$	420	$	46,114
Net Loss	$	(53,595)	$	42	$	(53,553)

The impact of adoption on the Company’s Consolidated Statement of Cash Flows for the year ending December 31, 2018 was as follows (in thousands):


	Year Ended December 31, 2018
			Balance without
	As Reported	Adjustments	Adoption of Topic 606
Statement of Cash Flows
Net Loss	(53,595)	42	(53,553)
Changes in operating assets and liabilities
Other receivables	10,223	(492)	9,731
Accounts payable and accrued expenses	(13,029)	450	(12,579)
Net cash used in operating activities	(37,939)	—	(37,939)

Leases (Tables)

12 Months Ended

Dec. 31, 2018

Leases [Abstract]

Capital Leased Assets

The following is an analysis of the leased property under capital leases by major class (in thousands):


	Asset Balances at December 31,
Class of property	2018		2017
Lab equipment	$	720	$	720
Leasehold improvements	27		27
Computer equipment	54		54
Total property under capital leases	801		801
Less accumulated depreciation and amortization	(703)		(652)
Capital leased assets, net	$	98	$	149

Minimum Rental Payments for Operating Leases


Year Ending December 31:
2019	$	1,105
2020	1,004
2021	923
2022	906
2023	909
Thereafter	6,570
Total	$	11,417

Leasehold improvements and equipment (Tables)

12 Months Ended

Dec. 31, 2018

Property, Plant and Equipment [Abstract]

Schedule of Leasehold Improvements and Equipment

Leasehold improvements and equipment at December 31, 2018 and 2017 consisted of the following:


	Year Ended December 31,
	2018		2017
Leasehold improvements	$	5,300	$	5,310
Computer and office equipment	1,984		2,326
Lab and leased equipment	3,398		3,979
Contract manufacturing organization equipment	30		114
Assets not placed in service	—		—
Total leasehold improvements and equipment	10,712		11,729
Less accumulated depreciation and amortization	(6,985)		(6,638)
Total leasehold improvements and equipment, net	$	3,727	$	5,091

Common Stock Equity Incentive Plans (Tables)

12 Months Ended

Dec. 31, 2018

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Authorized Increases under 2009 Stock Plan

The following table summarizes the authorized increases of common stock under the 2009 Plan:


Date Authorized						Authorized Shares Added
May 15, 2010						1,238,095
January 7, 2011						714,286
January 1, 2013						838,375
January 1, 2014						1,066,340
January 1, 2015						1,119,255
January 1, 2016						1,152,565
January 1, 2017						1,166,546
January 1, 2018						1,484,382

Stock Option Activity

The following table summarizes the stock option activity for the year ended December 31, 2018:


	Number of options	Weighted average exercise price		Weighted average remaining contractual term (years)
Outstanding at beginning of period	7,206,884	$	13.73
Options granted	1,657,523	6.85
Options exercised	(38,074)	3.78
Options forfeited	(459,062)	12.39
Options expired	(387,627)	25.30
Outstanding at end of period	7,979,644	11.86		4.5
Options exercisable at end of period	6,262,449	$	12.56	3.3

Assumptions Used in Black-Scholes Pricing Model for New Grants


	Years Ended December 31,
	2018	2017	2016
Number of options granted	1,657,523	1,526,787	1,346,758
Risk-free interest rate	2.61%-3.02%	1.91%-2.22%	1.19%-1.97%
Expected dividend yield	—	—	—
Expected volatility	76.2%-79.3%	68.9%-76.9%	67.1%-69.8%
Expected term (in years)	4.0-7.9	1.2-7.8	5.9-7.4
Weighted average grant-date fair value per share	$4.84	$7.72	$11.91

Intrinsic Value of options exercised and Fair Value of awards vested

The following table summarizes the intrinsic value of options exercised and the fair value of awards vested during the years ended December 31, 2018, 2017 and 2016:

Years Ended December 31,

2018

2017

2016

Intrinsic value of options exercised

$83,000

$1.0 million

$1.1 million

Fair value of awards vested

$13.0 million

$15.0 million

$15.1 million

Restricted Stock Activity

A summary of the Company's unvested restricted stock at December 31, 2018 and changes during the year ended December 31, 2018 is as follows:


	Restricted Stock	Weighted Average Grant Date Fair Value
Unvested at beginning of period	168,221	$	35.82
Granted	—	—
Vested	(88,864)	33.98
Forfeited/cancelled	(10,772)	38.63
Unvested at end of period	68,585	$	37.75

Income Taxes (Tables)

12 Months Ended

Dec. 31, 2018

Income Tax Disclosure [Abstract]

Income tax expense

Income tax benefit (expense) consists of (in thousands):


	Current		Deferred		Total
Year Ended December 31, 2018:
U.S. federal	$	—	$	—	$	—
State and local	6,968		—		6,968
	$	6,968	$	—	$	6,968

Year Ended December 31, 2017:
U.S. federal	$	332	$	140	$	472
State and local	87		—		87
	$	419	$	140	$	559

Year Ended December 31, 2016:
U.S. federal	$	6,469	$	—	$	6,469
State and local	(1,113)		—		(1,113)
	$	5,356	$	—	$	5,356

Schedule of deferred tax assets and liabilities

The tax effects of temporary differences that give rise to significant portions of deferred tax assets and the deferred tax liability at December 31, 2018 and 2017 are presented below (in thousands):


	Year Ended December 31,
	2018		2017
Deferred tax assets:
Net operating loss carryforwards	$	18,165	$	10,622
Federal research and development tax credits	28,283		26,327
Share-based compensation	14,150		11,780
Deferred rent	300		327
Accrued compensation	680		789
Unearned revenue	—		17
Charitable contributions	15		39
Leasehold improvements and equipment	417		297
Gross deferred tax assets	62,010		50,198
Less valuation allowance	(62,010)		(50,198)
Total deferred tax assets	—		—

Income tax rate reconciliation

A reconciliation of income taxes at the statutory federal income tax rate to net income tax benefit included in the accompanying statements of operations is set forth in the following table:


	Year ended December 31,
	2018		2017		2016
U.S. federal income tax benefit at the statutory rate	(21.00)	%	(35.00)	%	(35.00)	%
State income taxes, net of federal taxes	(10.07)		(.03)		.88
Loss in foreign subsidiary	1.20		7.36		15.88
Valuation allowance, including impact of tax reform	18.20		24.10		12.07
Other	.16		2.80		.25
Total	(11.51)	%	(.77)	%	(5.92)	%

Uncertain income tax positions

The changes in the Company's uncertain income tax positions for the year ended December 31, 2018 consisted of the following (in thousands):



	December 31, 2018
Beginning Balance - uncertain tax positions	$	653
Increases for tax positions related to current year	—
Decreases due to settlements with taxing authorities	—
Reductions due to lapsed statute of limitations	—
Ending Balance - uncertain tax positions	$	653

Loss Per Share (Tables)

12 Months Ended

Dec. 31, 2018

Earnings Per Share [Abstract]

Basic and Diluted Net Loss per Common Share

The following table presents the calculations of loss per share:


	Years Ended December 31,
	2018		2017		2016
Historical net loss per share
Numerator
Net loss attributable to common stockholders	$	(53,595)	$	(71,951)	$	(85,155)

Denominator
Basic and diluted weighted-average shares outstanding	37,191,262		31,304,309		28,979,327



Basic and diluted loss per share	$	(1.44)	$	(2.30)	$	(2.94)

Licensing Agreements (Tables)

12 Months Ended

Dec. 31, 2018

Licensing Agreements [Abstract]

Licensing Agreements

These obligations are contingent upon achieving the applicable milestone event, the timing of which cannot presently be determined. The milestone payments and royalty payments are in place through at least the expiration of certain of the Company's patents, which is currently 2029 and beyond.


Licensor						Aggregate potential milestone payments






Augusta University Research Institute under AURI IDO						$2.8 million per licensed product

Public Health Agency of Canada						$250,000

Restructuring Charges (Tables)

12 Months Ended

Dec. 31, 2018

Restructuring and Related Activities [Abstract]

Restructuring Charges

The following table shows the amount accrued for restructuring activities which is recorded within Accrued Expenses in the consolidated balance sheet (in thousands):


	Employee Severance Cost		Total
Balance as of December 31, 2017	$	207	$	207
Expensed	1,323		1,323
Cash Payments	881		881
Adjustments	—		—
Balance as of December 31, 2018	$	649	$	649

Quarterly Financial Information (Unaudited) (Tables)

12 Months Ended

Dec. 31, 2018

Quarterly Financial Information Disclosure [Abstract]

Quarterly Financial Information (Unaudited)


	First		Second		Third		Fourth
	(In thousands, except per share data)
Year Ended December 31, 2018
Grant and licensing revenue	$	9,900	$	2,252	$	120	$	202
Loss from operations	(18,706)		(17,748)		(15,038)		(10,946)
Net loss	(18,310)		(17,313)		(7,403)		(10,569)
Basic and diluted loss per share	$	(.49)	$	(.47)	$	(.20)	$	(.28)

Year Ended December 31, 2017
Grant and licensing revenue	$	2,761	$	10,370	$	5,482	$	10,098
Loss from operations	(21,198)		(16,727)		(20,905)		(14,051)
Net loss	(20,913)		(16,726)		(20,626)		(13,686)
Basic and diluted loss per share	$	(.72)	$	(.57)	$	(.69)	$	(.37)

Description of Business Activities (Details) - USD ($) $ in Thousands			1 Months Ended	3 Months Ended	12 Months Ended
	Feb. 04, 2013	Nov. 16, 2011	Oct. 31, 2017	Mar. 30, 2015	Dec. 31, 2017
IPO
Summary of Financings
Financing proceeds		$ 37,600
Follow-on Offering
Summary of Financings
Financing proceeds	$ 49,000
ATM Offering
Summary of Financings
Financing proceeds				$ 58,700	$ 19,300
Issuance of common stock (net of offering costs) (in shares)					1,940,656
Commission costs					$ 398
Other costs					$ 163
Public Offering
Summary of Financings
Financing proceeds			$ 55,200
Number of shares issued			5,750,000
Offering costs			$ 3,700

Significant Accounting Policies (Details) - USD ($)	3 Months Ended								12 Months Ended
Significant Accounting Policies (Details) - USD ($)	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Cash and Cash Equivalents
Cash and cash equivalents	$ 120,738,000				$ 158,708,000				$ 120,738,000	$ 158,708,000	$ 131,490,000	$ 195,620,000
Leasehold Improvements and Equipment
Deferred rents	998,000				1,100,000				998,000	1,100,000
Revenue Recognition
Grant and licensing revenue	202,000	$ 120,000	$ 2,252,000	$ 9,900,000	10,098,000	$ 5,482,000	$ 10,370,000	$ 2,761,000	12,474,000	28,711,000	$ 35,768,000
Receivables from government contracts	309,000				9,300,000				309,000	9,300,000
Unbilled expenses	0				465,000				0	465,000
Effective Income Tax Rate Reconciliation, percent
Uncertain Tax Positions	653,000				653,000				$ 653,000	653,000
Stock Option Valuation
Award vesting percentage									25.00%
Award vesting period									36 months
Expected dividend yield									0.00%
Notes payable and capital lease obligations	104,000				271,000				$ 104,000	$ 271,000
Future minimum lease payments	11,417,000								$ 11,417,000
Customer Concentration Risk \| Sales Revenue, Net \| Genentech
Stock Option Valuation
Concentration risk percentage									0.40%	1.20%	7.60%
Customer Concentration Risk \| Sales Revenue, Net \| Merck
Stock Option Valuation
Concentration risk percentage									9.20%	0.20%	2.30%
Computer and office equipment \| Minimum
Property, Plant and Equipment [Line Items]
Useful life									3 years
Computer and office equipment \| Maximum
Property, Plant and Equipment [Line Items]
Useful life									5 years
Lab and leased equipment
Property, Plant and Equipment [Line Items]
Useful life									5 years
Contract manufacturing organization equipment
Property, Plant and Equipment [Line Items]
Useful life									5 years
Accrued Expenses
Revenue Recognition
Accrued expenses for subcontractor fees incurred under government contracts	54,000				1,800,000				$ 54,000	$ 1,800,000
Accounts Payable
Revenue Recognition
Subcontractor fees in accounts payable	$ 161,000				$ 4,900,000				161,000	4,900,000
Grant [Member]
Revenue Recognition
Grant and licensing revenue									$ 11,268,000	$ 28,321,000	$ 32,242,000

Revenues (Effects of New Accounting Pronouncements) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Jan. 01, 2018
Disaggregation of Revenue [Line Items]
Prepaid expenses and other current assets	$ 5,536				$ 6,226				$ 5,536	$ 6,226		$ 5,762
Other receivables	459				10,176				459	10,176		10,682
Assets	130,939				180,697				130,939	180,697		180,739
Equity:
Accumulated deficit	(291,012)				(237,459)				(291,012)	(237,459)		(237,417)
Total liabilities and stockholders' equity	130,939				180,697				130,939	180,697		180,739
Grant and licensing revenue	202	$ 120	$ 2,252	$ 9,900	10,098	$ 5,482	$ 10,370	$ 2,761	12,474	28,711	$ 35,768
Licensing and collaboration revenue									1,206	390	3,526
Research and development									45,694	69,866	93,300
Net loss	$ (10,569)	$ (7,403)	$ (17,313)	$ (18,310)	$ (13,686)	$ (20,626)	$ (16,726)	$ (20,913)	(53,595)	(71,951)	(85,155)
Other receivables									10,223	14,350	(19,139)
Accounts payable and accrued expenses									(13,029)	(15,469)	24,770
Net cash used in operating activities									(37,939)	(48,281)	(65,947)
Difference between Revenue Guidance in Effect before and after Topic 606 [Member]
Disaggregation of Revenue [Line Items]
Prepaid expenses and other current assets												(464)
Other receivables												506
Assets												42
Equity:
Accumulated deficit												42
Total liabilities and stockholders' equity												$ 42
Calculated under Revenue Guidance in Effect before Topic 606 [Member]
Equity:
Research and development									46,114
Net loss									(53,553)
Other receivables									9,731
Accounts payable and accrued expenses									(12,579)
Net cash used in operating activities									(37,939)
Grant [Member]
Equity:
Grant and licensing revenue									11,268	$ 28,321	$ 32,242
Grant [Member] \| Calculated under Revenue Guidance in Effect before Topic 606 [Member]
Equity:
Grant and licensing revenue									11,614
License and Service [Member]
Equity:
Licensing and collaboration revenue									1,206
License and Service [Member] \| Calculated under Revenue Guidance in Effect before Topic 606 [Member]
Equity:
Licensing and collaboration revenue									1,322
Accounting Standards Update 2014-09 [Member] \| Difference between Revenue Guidance in Effect before and after Topic 606 [Member]
Equity:
Research and development									420
Net loss									42
Other receivables									(492)
Accounts payable and accrued expenses									450
Net cash used in operating activities									0
Accounting Standards Update 2014-09 [Member] \| Grant [Member] \| Difference between Revenue Guidance in Effect before and after Topic 606 [Member]
Equity:
Grant and licensing revenue									346
Accounting Standards Update 2014-09 [Member] \| License and Service [Member] \| Difference between Revenue Guidance in Effect before and after Topic 606 [Member]
Equity:
Licensing and collaboration revenue									$ 116

Leases (Details) - USD ($) $ in Thousands	12 Months Ended
Leases (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Capital Leases
Total property under capital leases	$ 801	$ 801
Less accumulated depreciation and amortization	(703)	(652)
Capital leased assets, net	98	149
Capital Leases
Rent expense	1,100	1,200	$ 1,700
Operating Leases
2019	1,105
2020	1,004
2021	923
2022	906
2023	909
Thereafter	6,570
Total	$ 11,417
Minimum
Capital Leases
Term of lease contract	1 year
Maximum
Capital Leases
Term of lease contract	3 years
Lab and leased equipment
Capital Leases
Total property under capital leases	$ 720	720
Leasehold improvements
Capital Leases
Total property under capital leases	27	27
Computer equipment
Capital Leases
Total property under capital leases	$ 54	$ 54

Leasehold improvements and equipment (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Property Subject to or Available for Operating Lease [Line Items]
Total leasehold improvements and equipment	$ 10,712	$ 11,729
Less accumulated depreciation and amortization	(6,985)	(6,638)
Total leasehold improvements and equipment, net	3,727	5,091
Leasehold improvements
Property Subject to or Available for Operating Lease [Line Items]
Total leasehold improvements and equipment	5,300	5,310
Computer and office equipment
Property Subject to or Available for Operating Lease [Line Items]
Total leasehold improvements and equipment	1,984	2,326
Lab and leased equipment
Property Subject to or Available for Operating Lease [Line Items]
Total leasehold improvements and equipment	3,398	3,979
Contract manufacturing organization equipment
Property Subject to or Available for Operating Lease [Line Items]
Total leasehold improvements and equipment	30	114
Assets not placed in service
Property Subject to or Available for Operating Lease [Line Items]
Total leasehold improvements and equipment	$ 0	$ 0

Long-Term Debt Conversion to Royalty Obligation (Details) ft² in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018 USD ($)	Sep. 30, 2018 USD ($)	Jun. 30, 2018 USD ($)	Mar. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Sep. 30, 2017 USD ($)	Jun. 30, 2017 USD ($)	Mar. 31, 2017 USD ($) ft²	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2012 USD ($)	Dec. 31, 2009 USD ($)	Dec. 31, 2014	Dec. 31, 2011 USD ($)	Mar. 31, 2010 USD ($) position	Mar. 31, 2005 USD ($)
Debt Instrument
Royalty obligation payable to Iowa Economic Development Authority	$ 6,000,000				$ 6,000,000				$ 6,000,000	$ 6,000,000
Grant and licensing revenue	$ 202,000	$ 120,000	$ 2,252,000	$ 9,900,000	10,098,000	$ 5,482,000	$ 10,370,000	$ 2,761,000	$ 12,474,000	28,711,000	$ 35,768,000
Loans Payable \| Iowa Department of Economic Development Loan 2005
Debt Instrument
Original Available Balance																	$ 6,000,000.0
Outstanding balance															$ 6,000,000.0
Loans Payable \| Iowa Economic Development Authority Royalty Obligation 2012
Debt Instrument
Revised royalty rate	0.50%								0.50%
Revised royalty maximum amount	$ 6,800,000								$ 6,800,000
Royalty obligation payable to Iowa Economic Development Authority	6,000,000.0								6,000,000.0
Loans Payable \| Iowa State University Research Park Loan 2009
Debt Instrument
Original Available Balance													$ 800,000
Outstanding balance	$ 0				29,000				$ 0	29,000
Debt term													8 years
Stated interest rate													3.00%	5.00%
Increase to interest rate after completion of improvements													5 years
Debt default rate	8.00%								8.00%
Loans Payable \| Iowa State University Research Park Loan 2012
Debt Instrument
Original Available Balance												$ 456,000
Outstanding balance	$ 111,000				$ 169,000				$ 111,000	$ 169,000
Debt term												8 years
Stated interest rate					5.00%					5.00%		3.00%
Increase to interest rate after completion of improvements												5 years
Debt default rate												8.00%
Loans Payable \| City of Ames Forgivable Loan 2010
Debt Instrument
Original Available Balance																$ 400,000
Jobs by March 10, 2015 \| position																150
Term of lease contract																5 years
Lease square feet \| ft²								20
Renewal term of lease																5 years
Grant [Member]
Debt Instrument
Grant and licensing revenue									$ 11,268,000	$ 28,321,000	32,242,000
Grant [Member] \| City of Ames Forgivable Loan 2010
Debt Instrument
Grant and licensing revenue											$ 397,000

License and Research Collaboration Agreements (Details) - USD ($)	1 Months Ended		12 Months Ended
	Feb. 28, 2015	Dec. 31, 2014	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2014
Deferred Revenue Arrangement [Line Items]
Licensing and collaboration revenue			$ 1,206,000	$ 390,000	$ 3,526,000
Genentech Inc. \| Collaborative Arrangement
Deferred Revenue Arrangement [Line Items]
Upfront cash payments						$ 150,000,000.0
Licensing and collaboration revenue			56,000	335,000	2,700,000
Alliance manager			56,000	335,000	670,000
Deferred revenue			$ 0	$ 56,000	391,000
JRC revenue					180,000
Employee labor revenue					1,900,000
Merck, Sharpe and Dohme Corp \| Collaborative Arrangement
Deferred Revenue Arrangement [Line Items]
Upfront cash payments	$ 20,000,000.0	$ 30,000,000.0
Licensing and collaboration revenue					815,300
Revenue allocated to other deliverables					53,800
Ebola costs revenue recognition					$ 761,500

Stockholders' Equity (Details) - shares	12 Months Ended
Stockholders' Equity (Details) - shares	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Stockholders' Equity Note [Abstract]
Votes per share	1
Blank check preferred stock, outstanding shares	0	0	0
Blank check preferred stock, authorized shares	5,000,000	5,000,000

Common Stock Equity Incentive Plans (Narrative) (Details) - USD ($)											12 Months Ended
	Jan. 01, 2019	Jan. 01, 2018	Jan. 01, 2017	Jan. 01, 2016	Jan. 01, 2015	Jan. 01, 2014	May 09, 2013	Jan. 01, 2013	Jan. 07, 2011	May 15, 2010	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Nov. 10, 2011
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense											$ 17,100,000	$ 18,500,000	$ 16,700,000
Total compensation cost related to non-vested option awards											8,300,000
Tax benefit from share-based compensation											$ 0	$ 0	$ 0
Award vesting percentage											25.00%
Award vesting period											36 months
Intrinsic value of stock options (in dollars per share)											$ 1.52
Intrinsic value of stock options outstanding											$ 2,357
Employee Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted Average Vesting Period for Non-vested Option Awards, In Years											2 years 1 month 6 days
Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted Average Vesting Period for Non-vested Option Awards, In Years												10 months 24 days
Granted (in shares)											0
Total unrecognized compensation cost											$ 1,000,000.0
Fair value of vested awards											$ 673,508
2009 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized											11,722,602	10,238,220
Number of shares available for grant											1,879,686	1,195,358
Number of authorized shares added		1,484,382	1,166,546	1,152,565	1,119,255	1,066,340		838,375	714,286	1,238,095
Evergreen increase											4.00%
2009 Equity Incentive Plan \| Employee Stock Option \| First Anniversary
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting percentage											25.00%
2009 Equity Incentive Plan \| Employee Stock Option \| Thereafter
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period											36 months
2010 Non-Employee Directors' Stock Option Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized														238,095
Number of shares available for grant											0
Number of authorized shares added							161,905
2010 Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized														214,285
Number of shares available for grant											53,509
Number of authorized shares added							185,715
Shares issued											48,487	70,787
Subsequent Event \| 2009 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of authorized shares added	1,490,048

Common Stock Equity Incentive Plans (Authorized Increases of Common Stock) (Details) - shares	Jan. 01, 2018	Jan. 01, 2017	Jan. 01, 2016	Jan. 01, 2015	Jan. 01, 2014	Jan. 01, 2013	Jan. 07, 2011	May 15, 2010
2009 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Authorized Shares Added	1,484,382	1,166,546	1,152,565	1,119,255	1,066,340	838,375	714,286	1,238,095

Common Stock Equity Incentive Plans (Stock Option Activity) (Details) - Employee Stock Option - $ / shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Number of options
Outstanding at beginning of period	7,206,884
Options granted (in shares)	1,657,523	1,526,787	1,346,758
Options exercised (in shares)	(38,074)
Options forfeited (in shares)	(459,062)
Options expired (in shares)	(387,627)
Outstanding at end of period	7,979,644	7,206,884
Weighted average exercise price
Outstanding at beginning of period, weighted average exercise price (in dollars per share)	$ 13.73
Options granted, weighted average exercise price (in dollars per share)	6.85
Options exercised, weighted average exercise price (in dollars per share)	3.78
Options forfeited, weighted average exercise price (in dollars per share)	12.39
Options expired, weighted average exercise price (in dollars per share)	25.30
Outstanding at end of period, weighted average exercise price (in dollars per share)	$ 11.86	$ 13.73
Options exercisable at end of period (in shares)	6,262,449
Exercisable, weighted average exercise price (in dollars per share)	$ 12.56
Outstanding, weighted average remaining contractual term, in years	4 years 6 months
Exercisable, weighted average remaining contractual term, in years	3 years 3 months 18 days

Common Stock Equity Incentive Plans (Range of Assumptions Used) (Details) - $ / shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected dividend yield	0.00%
Employee Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of options granted (in shares)	1,657,523	1,526,787	1,346,758
Expected dividend yield	0.00%	0.00%	0.00%
Risk-free interest rate, minimum	2.61%	1.91%	1.19%
Risk-free interest rate, maximum	3.02%	2.22%	1.97%
Weighted average grant-date fair value per share (in dollars per share)	$ 4.84	$ 7.72	$ 11.91
Volatility Rate, Minimum	76.20%	68.90%	67.10%
Volatility Rate, Maximum	79.30%	76.90%	69.80%
Employee Stock Option \| Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected Term	4 years	1 year 2 months 12 days	5 years 10 months 24 days
Employee Stock Option \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected Term	7 years 10 months 24 days	7 years 9 months 18 days	7 years 4 months 24 days

Common Stock Equity Incentive Plans (Intrinsic Value of Options Exercised) (Details) - Employee Stock Option - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Intrinsic value of options exercised	$ 83	$ 1,000	$ 1,100
Fair value of awards vested	$ 13,000	$ 15,000	$ 15,100

Common Stock Equity Incentive Plans (Restricted Stock Activity) (Details) - Restricted Stock	12 Months Ended
	Dec. 31, 2018 $ / shares shares
Restricted Stock
Unvested at beginning of period (in shares) \| shares	168,221
Granted (in shares) \| shares	0
Vested (in shares) \| shares	(88,864)
Forfeited/cancelled (in shares) \| shares	(10,772)
Unvested at end of period (in shares) \| shares	68,585
Weighted Average Grant Date Fair Value
Beginning of period, weighted average grant date fair value (in dollars per share) \| $ / shares	$ 35.82
Granted, weighted average grant date fair value (in dollars per share) \| $ / shares	0
Vested, weighted average grant date fair value (in dollars per share) \| $ / shares	33.98
Forfeited/cancelled, weighted average grant date fair value (in dollars per share) \| $ / shares	38.63
End of period, weighted average grant date fair value (in dollars per share) \| $ / shares	$ 37.75

Income Taxes Narrative (Details) - USD ($)	12 Months Ended
Income Taxes Narrative (Details) - USD ($)	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Operating Loss Carryforwards [Line Items]
Income tax benefit from impact of the Tax Act		$ 140,000
Deferred Tax Valuation Allowance	$ (62,010,000)	(50,198,000)
Net change total valuation allowance	11,800,000	15,100,000
Income tax benefit	6,968,000	559,000	$ 5,356,000
Income tax interest and penalties	82,000	$ 335,000	$ 0
Domestic Tax Authority
Operating Loss Carryforwards [Line Items]
Operating loss carryforward	74,500,000
Domestic Tax Authority \| Research Tax Credit Carryforward
Operating Loss Carryforwards [Line Items]
Tax credit carryforward	$ 28,300,000

Income Taxes Income Tax Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Current
U.S. federal	$ 0	$ 332	$ 6,469
State and local	6,968	87	(1,113)
Current income tax expense	6,968	419	5,356
Deferred
U.S. federal	0	140	0
State and local	0	0	0
Deferred income tax expense	0	140	0
U.S. federal	0	472
State and local	6,968	87	(1,113)
Income tax benefit (expense)	$ 6,968	$ 559	$ 5,356

Income Taxes Deferred Tax (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Net operating loss carryforwards	$ 18,165	$ 10,622
Federal research and development tax credits	28,283	26,327
Share-based compensation	14,150	11,780
Deferred rent	300	327
Accrued compensation	680	789
Unearned revenue	0	17
Charitable contributions	15	39
Leasehold improvements and equipment	417	297
Gross deferred tax assets	62,010	50,198
Less valuation allowance	(62,010)	(50,198)
Total deferred tax assets	$ 0	$ 0

Income Taxes Income Tax Rate Reconciliation (Details)	12 Months Ended
Income Taxes Income Tax Rate Reconciliation (Details)	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
U.S. federal income tax expense (benefit) at the statutory rate	(21.00%)	(35.00%)	(35.00%)
State income taxes, net of federal taxes	(10.07%)	(0.03%)	0.88%
Loss in foreign subsidiary	1.20%	7.36%	15.88%
Valuation allowance, including impact of tax reform	18.20%	24.10%	12.07%
Other	0.16%	2.80%	0.25%
Total	(11.51%)	(0.77%)	(5.92%)

Income Taxes Uncertain Income Tax Positions (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2018 USD ($)
Reconciliation of Uncertain Income Tax Positions
Beginning Balance - uncertain tax positions	$ 653
Increases for tax positions related to current year	0
Decreases due to settlements with taxing authorities	0
Reductions due to lapsed statute of limitations	0
Ending Balance - uncertain tax positions	$ 653

Loss Per Share (Net Loss Per Share Computation) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Numerator
Net loss attributable to common stockholders	$ (10,569)	$ (7,403)	$ (17,313)	$ (18,310)	$ (13,686)	$ (20,626)	$ (16,726)	$ (20,913)	$ (53,595)	$ (71,951)	$ (85,155)
Denominator
Basic weighted-average shares outstanding (in shares)									37,191,262	31,304,309	28,979,327
Basic and diluted loss per share (in dollars per share)									$ (1.44)	$ (2.30)	$ (2.94)

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References + Details

Loss Per Share (Antidilutive Securities) (Details) - shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Employee Stock Option
Antidilutive Securities Excluded from Computation of Earnings Per Share
Potentially dilutive securities excluded from computation of diluted net loss per share	7,979,644	7,206,884
Restricted Stock
Antidilutive Securities Excluded from Computation of Earnings Per Share
Potentially dilutive securities excluded from computation of diluted net loss per share	68,585	168,221

Licensing Agreements (Details) - USD ($) $ in Thousands	12 Months Ended
Licensing Agreements (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Licensing Agreements
Licensing payments under agreements	$ 32	$ 1,400	$ 2,000
Augusta University Research Institute under AURI IDO
Licensing Agreements
Aggregate potential milestone payment per licensed product		2,800
Public Health Agency of Canada
Licensing Agreements
Aggregate potential milestone payment per licensed product		$ 250

Employee Benefit Plans (Details) - USD ($) $ in Thousands	12 Months Ended
Employee Benefit Plans (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Defined Benefit Plan Disclosure [Line Items]
Defined contributions	$ 261	$ 361	$ 482
Discretionary contributions	$ 303	$ 401	$ 446
Minimum
Defined Benefit Plan Disclosure [Line Items]
Duration of payments	6 months
Maximum
Defined Benefit Plan Disclosure [Line Items]
Duration of payments	24 months

Restructuring Charges (Details) - USD ($) $ in Thousands	1 Months Ended	12 Months Ended
Restructuring Charges (Details) - USD ($) $ in Thousands	Jul. 31, 2017	Dec. 31, 2018	Dec. 31, 2017
Restructuring Cost and Reserve [Line Items]
Percentage reduction in force	50.00%
Restructuring Reserve [Roll Forward]
Beginning balance		$ 207
Expensed		1,323	$ 1,700
Cash Payments		881
Adjustments		0
Ending balance		649	207
Employee Severance
Restructuring Reserve [Roll Forward]
Beginning balance		207
Expensed		1,323
Cash Payments		881
Adjustments		0
Ending balance		649	207
General and Administrative Expense
Restructuring Reserve [Roll Forward]
Expensed		800	1,100
Research and Development Expense
Restructuring Reserve [Roll Forward]
Expensed		$ 500	$ 600

Quarterly Financial Information (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Quarterly Financial Information Disclosure [Abstract]
Grant and licensing revenue	$ 202	$ 120	$ 2,252	$ 9,900	$ 10,098	$ 5,482	$ 10,370	$ 2,761	$ 12,474	$ 28,711	$ 35,768
Loss from operations	(10,946)	(15,038)	(17,748)	(18,706)	(14,051)	(20,905)	(16,727)	(21,198)	(62,438)	(72,881)	(90,758)
Net loss	$ (10,569)	$ (7,403)	$ (17,313)	$ (18,310)	$ (13,686)	$ (20,626)	$ (16,726)	$ (20,913)	$ (53,595)	$ (71,951)	$ (85,155)
Basic and diluted loss per share (in dollars per share)	$ (0.28)	$ (0.20)	$ (0.47)	$ (0.49)	$ (0.37)	$ (0.69)	$ (0.57)	$ (0.72)

- Definition

The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 220
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-04(19))
-URI http://asc.fasb.org/extlink&oid=114873790&loc=SL114874131-224263

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 45
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=109260490&loc=d3e1337-109256

Reference 3: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 55
-Paragraph 52
-URI http://asc.fasb.org/extlink&oid=109256448&loc=d3e4984-109258

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03(21))
-URI http://asc.fasb.org/extlink&oid=115205541&loc=SL114868664-224227

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 250
-SubTopic 10
-Section 50
-Paragraph 11
-URI http://asc.fasb.org/extlink&oid=109234566&loc=d3e22694-107794

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=6371337&loc=d3e3550-109257

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=109260490&loc=d3e1252-109256

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 220
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04(23))
-URI http://asc.fasb.org/extlink&oid=114873765&loc=SL114874048-224260

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 45
-Paragraph 60B
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=109260490&loc=SL5780133-109256

+ Details

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References + Details