Palvella Therapeutics (PVLA) 10-Q17 May 212021 Q1 Quarterly reportFinancial data

Company Profile

Cover Page

Cover Page - shares	3 Months Ended
Cover Page - shares	Mar. 31, 2021	May 12, 2021
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Mar. 31, 2021
Document Transition Report	false
Entity File Number	001-37471
Entity Registrant Name	PIERIS PHARMACEUTICALS, INC.
Entity Incorporation, State or Country Code	NV
Entity Tax Identification Number	30-0784346
Entity Address, Address Line One	255 State Street
Entity Address, Address Line Two	9th Floor
Entity Address, City or Town	Boston,
Entity Address, State or Province	MA
Entity Address, Country	US
Entity Address, Postal Zip Code	02109
City Area Code	857
Local Phone Number	246-8998
Title of 12(b) Security	Common Stock, $0.001 par value per share
Trading Symbol	PIRS
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		63,303,219
Amendment Flag	false
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q1
Entity Central Index Key	0001583648
Current Fiscal Year End Date	--12-31

CONDENSED CONSOLIDATED BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 66,835	$ 70,436
Accounts receivable	15,810	1,706
Prepaid expenses and other current assets	5,627	3,579
Total current assets	88,272	75,721
Property and equipment, net	20,512	22,046
Operating lease right-of-use assets	3,789	3,934
Other non-current assets	3,213	3,309
Total assets	115,786	105,010
Current liabilities:
Accounts payable	3,467	1,787
Accrued expenses and other current liabilities	9,562	7,731
Deferred revenues, current portion	17,236	12,627
Total current liabilities	30,265	22,145
Deferred revenue, net of current portion	32,315	35,900
Operating lease liabilities	14,970	15,932
Other long-term liabilities	0	6
Total liabilities	77,550	73,983
Stockholders’ equity:
Preferred stock	0	0
Common stock	60	56
Additional paid-in capital	253,560	242,672
Accumulated other comprehensive loss	194	(295)
Accumulated deficit	(215,578)	(211,406)
Total stockholders’ equity	38,236	31,027
Total liabilities and stockholders’ equity	$ 115,786	$ 105,010

CONDENSED CONSOLIDATED STATEMEN

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Revenue
Customer revenue	$ 14,866	$ 8,885
Collaboration revenue	767	4,376
Total revenue	15,633	13,261
Operating expenses
Research and development	16,562	12,758
General and administrative	4,130	4,359
Total operating expenses	20,692	17,117
Loss from operations	(5,059)	(3,856)
Other income (expense)
Interest income	3	319
Other income (expense)	884	(60)
Net loss	(4,172)	(3,597)
Other comprehensive income:
Foreign currency translation	489	652
Unrealized gain on available-for-sale securities	0	116
Comprehensive loss	$ (3,683)	$ (2,829)
Net loss per share
Basic and diluted (USD per share)	$ (0.07)	$ (0.07)
Weighted average number of common shares outstanding
Basic and diluted (shares)	56,297	55,212

CONDENSED CONSOLIDATED STATEM_2

CONDENSED CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY - USD ($) shares in Thousands, $ in Thousands	Total	Preferred shares	Common shares	Additional paid-in capital	Accumulated other comprehensive loss	Accumulated deficit
Balance at beginning of period (shares) at Dec. 31, 2019		11	55,212
Balance at beginning of period at Dec. 31, 2019	$ 51,352		$ 55	$ 227,468	$ (1,995)	$ (174,176)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(3,597)					(3,597)
Foreign currency translation adjustment	652				652
Unrealized gain on investments	116				116
Stock based compensation expense	1,283			1,283
Balance at end of period (shares) at Mar. 31, 2020		11	55,212
Balance at end of period at Mar. 31, 2020	49,806		$ 55	228,751	(1,227)	(177,773)
Balance at beginning of period (shares) at Dec. 31, 2020		14	56,003
Balance at beginning of period at Dec. 31, 2020	31,027		$ 56	242,672	(295)	(211,406)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(4,172)					(4,172)
Foreign currency translation adjustment	489				489
Stock based compensation expense	1,199			1,199
Issuance of common stock resulting from exercise of stock options	20			20
Issuance of common stock resulting from exercise of stock options (in shares)			10
Issuance of common stock pursuant to private placement offering	9,673		$ 4	9,669
Issuance of common stock pursuant to private placement offering (in shares)			3,706
Balance at end of period (shares) at Mar. 31, 2021		14	59,719
Balance at end of period at Mar. 31, 2021	$ 38,236		$ 60	$ 253,560	$ 194	$ (215,578)

CONDENSED CONSOLIDATED STATEM_3

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Operating activities:
Net loss	$ (4,172)	$ (3,597)
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation and amortization	625	339
Right-of-use asset amortization	(25)	199
Stock-based compensation	1,199	1,283
Other non-cash transactions	(41)	100
Changes in operating assets and liabilities	(9,724)	(13,455)
Net cash used in operating activities	(12,138)	(15,131)
Investing activities:
Purchases of property and equipment	(28)	(1,927)
Proceeds from maturity of investments	0	28,373
Purchases of investments	0	(26,032)
Net cash (used in)/provided by investing activities	(28)	414
Financing activities:
Proceeds from exercise of stock options	20	0
Issuance of common stock, net of issuance costs	9,673	0
Net cash provided by financing activities	9,693	0
Effect of exchange rate change on cash and cash equivalents	(1,128)	(112)
Net decrease in cash and cash equivalents	(3,601)	(14,829)
Cash and cash equivalents at beginning of period	70,436	62,260
Cash and cash equivalents at end of period	66,835	47,431
Supplemental cash flow disclosures:
Net unrealized gain on investments	0	46
Property and equipment included in accounts payable	$ 36	$ 590

Corporate Information

Corporate Information	3 Months Ended
Corporate Information	Mar. 31, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Corporate Information	Corporate Information Pieris Pharmaceuticals, Inc. was founded in May 2013, and acquired 100% interest in Pieris Pharmaceuticals GmbH (formerly Pieris AG, a German company that was founded in 2001) in December 2014. Pieris Pharmaceuticals, Inc. and its wholly-owned subsidiaries, hereinafter collectively Pieris, or the Company, is a clinical-stage biopharmaceutical company that discovers and develops Anticalin-based drugs to target validated disease pathways in unique and transformative ways. Pieris’ corporate headquarters is located in Boston, Massachusetts and its research facility is located in Hallbergmoos, Germany. Pieris’ clinical pipeline includes an inhaled IL-4Rα antagonist Anticalin protein to treat moderate-to-severe asthma and an immuno-oncology, or IO, bispecific targeting 4-1BB and HER2. The Company’s core Anticalin technology and platform was developed in Germany, and the Company has partnership arrangements with several major multi-national pharmaceutical companies. The Company is subject to risks common to companies in the biotechnology industry, including but not limited to, the need for additional capital, risks of failure of preclinical studies and clinical trials, the need to obtain marketing approval and reimbursement for any drug product candidate that it may identify and develop, the need to successfully commercialize and gain market acceptance of its product candidates, dependence on key personnel, protection of proprietary technology, compliance with government regulations, development of technological innovations by competitors, reliance on third-party manufacturers and the ability to transition from pilot-scale production to large-scale manufacturing of products. As of March 31, 2021, cash and cash equivalents were $66.8 million, which does not include the $13.0 million milestone payment earned from AstraZeneca AB, or AstraZeneca, related to the initiation of the phase 2a study for PRS-060/AZD1402, $10.0 million in gross proceeds from the Company’s private placement of common stock to AstraZeneca, which closed on April 1, 2021 (see Note 3), and the $10.0 million upfront payment due from Boston Pharmaceuticals for the Exclusive Product License Agreement entered into on April 24, 2021 (see Note 3). The Company’s net loss was $4.2 million and $3.6 million for the quarters ended March 31, 2021 and 2020, respectively. The Company has incurred net losses since inception and had an accumulated deficit of $215.6 million as of March 31, 2021. Net losses and negative cash flows from operations have had, and will continue to have, an adverse effect on the Company’s stockholders’ equity and working capital. The Company expects to continue to incur operating losses for at least the next several years. The future success of the Company is dependent on its ability to identify and develop its product candidates, expand its corporate infrastructure and ultimately upon its ability to attain profitable operations. The Company has devoted substantially all of its financial resources and efforts to research and development and general and administrative expenses to support such research and development. The Company has several research and development programs underway in varying stages of development and it expects that these programs will continue to require increasing amounts of cash for development, conducting clinical trials, and testing and manufacturing of product material. Cash necessary to fund operations will increase significantly over the next several years as the Company continues to conduct these activities necessary to pursue governmental regulatory approval of clinical-stage programs and other product candidates. The Company plans to raise additional capital to fulfill its operating and capital requirements through public or private equity financings, utilization of its current "at the market offering" program, or ATM Program, strategic collaborations, licensing arrangements and/or the achievement of milestones under its collaborative agreements. The funding requirements of the Company’s operating plans, however, are based on estimates that are subject to risks and uncertainties and may change as a result of many factors currently unknown. Although management continues to pursue these funding plans, there is no assurance that the Company will be successful in obtaining sufficient funding on terms acceptable to the Company to fund continuing operations, if at all. Until such time that the Company can generate substantial product revenues, if ever, the Company expects to finance its cash needs through a combination of equity offerings, debt financings, strategic partnerships and licensing arrangements. The terms of any future financing may adversely affect the holdings or the rights of the Company’s existing stockholders. The Company believes that its currently available funds will be sufficient to fund the Company’s operations through at least the next twelve months from the issuance of this Quarterly Report on Form 10-Q. The Company's belief with respect to its ability

Summary of Significant Accounti

Summary of Significant Accounting Policies	3 Months Ended
Summary of Significant Accounting Policies	Mar. 31, 2021
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies The Company’s significant accounting policies are described in Note 2—Summary of Significant Accounting Policies, in the Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2020. There has been no material change to the significant accounting policies during the three months ended March 31, 2021. Unaudited Interim Financial Information The accompanying unaudited condensed consolidated financial statements included herein have been prepared by the Company in accordance with accounting principles generally accepted in the United States, or U.S. GAAP, for interim financial information and pursuant to the rules and regulations of the SEC. Accordingly, certain information and footnote disclosures normally included in financial statements prepared in accordance with U.S. GAAP have been condensed or omitted pursuant to such rules and regulations. In the opinion of management, all adjustments, consisting of normal recurring adjustments, and disclosures considered necessary for a fair presentation of interim period results have been included. Interim results for the three months ended March 31, 2021 are not necessarily indicative of results that may be expected for the year ending December 31, 2021. For further information, refer to the financial statements and footnotes thereto included in the Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2020, which was filed with the SEC on March 31, 2021. Basis of Presentation and Use of Estimates The accompanying condensed consolidated financial statements of Pieris Pharmaceuticals, Inc. and its wholly-owned subsidiaries were prepared in accordance with U.S. GAAP. The condensed consolidated financial statements include the accounts of all subsidiaries. All intercompany balances and transactions have been eliminated. The preparation of the financial statements in accordance with U.S. GAAP requires management to make estimates, judgments and assumptions that affect the reported amounts of assets, liabilities, revenues, expenses and the related disclosures at the date of the financial statements and during the reporting period. Significant estimates are used for, but are not limited to, revenue recognition; deferred tax assets, deferred tax liabilities and valuation allowances; determination of the incremental borrowing rate to calculate right-of-use assets and lease liabilities; beneficial conversion features; fair value of stock options, preferred stock, and warrants; and various accruals. Management evaluates its estimates on an ongoing basis. Actual results and outcomes could differ materially from management’s estimates, judgments and assumptions. Cash, Cash Equivalents and Investments The Company determines the appropriate classification of its investments at the time of purchase. All liquid investments with original maturities of 90 days or less from the purchase date and for which there is an active market are considered to be cash equivalents. The Company’s investments are comprised of money market, asset backed securities, government treasuries and corporate bonds that are classified as available-for-sale in accordance with FASB Accounting Standards Codification, or ASC, 320, Investments—Debt and Equity Securities . The Company classifies investments available to fund current operations as current assets on its balance sheets. Available-for-sale investments are recorded at fair value, with unrealized gains or losses included in accumulated other comprehensive loss on the Company’s balance sheets. Realized gains and losses are determined using the specific identification method and are included as a component of other income. The Company reviews investments for other-than-temporary impairment whenever the fair value of an investment is less than the amortized cost and evidence indicates that an investment’s carrying amount is not recoverable within a reasonable period of time. To determine whether an impairment is other-than temporary, the Company considers its intent to sell or whether it is more likely than not that the Company will be required to sell the investment before recovery of the investment’s amortized cost basis. Evidence considered in this assessment includes reasons for the impairment, the severity and the duration of the impairment and changes in value subsequent to period end. Concentration of Credit Risk and Off-Balance Sheet Risk The Company has no financial instruments with off-balance sheet risk such as foreign exchange contracts, option contracts or other foreign hedging arrangements. Financial instruments that subject Pieris to concentrations of credit risk include cash and cash equivalents, investments, and accounts receivable. The Company’s cash, cash equivalents, and investments are held in accounts with financial institutions that management believes are creditworthy. The Company’s investment policy includes guidelines on the quality of the institutions and financial instruments and defines allowable investments that the Company believes minimizes the exposure to concentration of credit risk. The Company has not experienced any credit losses in such accounts and does not believe it is exposed to any significant credit risk on these funds. Accounts receivable primarily consist of amounts due under strategic partnership and other license agreements with major multi-national pharmaceutical companies for which the Company does not obtain collateral. Fair Value Measurement The Company is required to disclose information on all assets and liabilities reported at fair value that enables an assessment of the inputs used in determining the reported fair values. FASB ASC Topic 820, Fair Value Measurement and Disclosures , established a hierarchy of inputs used in measuring fair value that maximizes the use of observable inputs and minimizes the use of unobservable inputs by requiring that the observable inputs be used when available. Observable inputs are inputs that market participants would use in pricing the financial instrument based on market data obtained from sources independent of the Company. Unobservable inputs are inputs that reflect the Company’s assumptions about the inputs that market participants would use in pricing the financial instrument and are developed based on the best information available in the circumstances. The fair value hierarchy applies only to the valuation inputs used in determining the reported or disclosed fair value of the financial instruments and is not a measure of the investment credit quality. Fair value measurements are classified and disclosed in one of the following three categories: • Level 1 inputs are quoted prices in active markets for identical assets or liabilities that the reporting entity has the ability to access at the measurement date. • Level 2 utilizes quoted market prices in markets that are not active, broker or dealer quotations or alternative pricing sources with reasonable levels of price transparency. • Level 3 inputs are unobservable inputs for the asset or liability in which there is little, if any, market activity for the asset or liability at the measurement date. To the extent that valuation is based on models or inputs that are less observable or unobservable in the market, the determination of fair value requires more judgment. Accordingly, the degree of judgment exercised by the Company in determining fair value is greatest for instruments categorized in Level 3. A financial instrument’s level within the fair value hierarchy is based on the lowest level of any input that is significant to the fair value measurement. Financial instruments measured at fair value on a recurring basis include cash equivalents (see Note 4). An entity may elect to measure many financial instruments and certain other items at fair value at specified election dates. Subsequent unrealized gains and losses on items for which the fair value option has been elected will be reported in net loss. The Company did not elect to measure any additional financial instruments or other items at fair value. Property and Equipment Property and equipment are recorded at acquisition cost, less accumulated depreciation and impairment. Depreciation on property and equipment is calculated using the straight-line method over the remaining estimated useful lives of the assets. Maintenance and repairs to these assets are charged to expenses as occurred. The estimated useful life of the different groups of property and equipment is as follows: Asset Classification Estimated useful life (in years) Leasehold improvements shorter of useful life or remaining life of the lease Laboratory furniture and equipment 8 - 14 Office furniture and equipment 5 - 13 Computer and equipment 3 - 7 Revenue Recognition The Company has entered into several licensing agreements with collaboration partners for the development of Anticalin therapeutics against a variety of targets. The terms of these agreements provide for the transfer of multiple goods or services which may include: (i) licenses, or options to obtain licenses, to the Company’s Anticalin technology and/or specific programs and (ii) research and development activities to be performed on behalf of or with a collaborative partner. Payments to Pieris under these agreements may include upfront fees (which include license and option fees), payments for research and development activities, payments based upon the achievement of certain milestones and royalties on product sales. There are no performance, cancellation, termination or refund provisions in any of the arrangements that could result in material financial consequences to Pieris. Collaborative Arrangements The Company considers the nature and contractual terms of an arrangement and assesses whether the arrangement involves a joint operating activity pursuant to which it is an active participant and exposed to significant risks and rewards with respect to the arrangement. If the Company is an active participant and exposed to the significant risks and rewards with respect to the arrangement, it accounts for these arrangements pursuant to ASC 808, Collaborative Arrangements , or ASC 808, and applies a systematic and rational approach to recognize revenue. The Company classifies payments received as revenue and payments made as a reduction of revenue in the period in which they are earned. Revenue recognized under a collaborative arrangement involving a participant that is not a customer is presented as Collaboration Revenue in the Statement of Operations. Revenue from Contracts with Customers In accordance with ASC 606, revenue is recognized when a customer obtains control of promised goods or services. The amount of revenue recognized reflects the consideration to which the Company expects to be entitled in exchange for these goods and services. To achieve this core principle, the Company applies the following five steps: 1) identify the customer contract; 2) identify the contract’s performance obligations; 3) determine the transaction price; 4) allocate the transaction price to the performance obligations; and 5) recognize revenue when or as a performance obligation is satisfied. The Company evaluates all promised goods and services within a customer contract and determines which of such goods and services are separate performance obligations. This evaluation includes an assessment of whether the good or service is capable of being distinct and whether the good or service is separable from other promises in the contract. In assessing whether promised goods or services are distinct, the Company considers factors such as the stage of development of the underlying intellectual property and the capabilities of the customer to develop the intellectual property on their own or whether the required expertise is readily available. Licensing arrangements are analyzed to determine whether the promised goods or services, which often include licenses, research and development services and governance committee services, are distinct or whether they must be accounted for as part of a combined performance obligation. If the license is considered not to be distinct, the license would then be combined with other promised goods or services as a combined performance obligation. If the Company is involved in a governance committee, it assesses whether its involvement constitutes a separate performance obligation. When governance committee services are determined to be separate performance obligations, the Company determines the fair value to be allocated to this promised service. Certain contracts contain optional and additional items, which are considered marketing offers and are accounted for as separate contracts with the customer if such option is elected by the customer, unless the option provides a material right which would not be provided without entering into the contract. An option that is considered a material right is accounted for as a separate performance obligation. The transaction price is determined based on the consideration to which the Company will be entitled in exchange for transferring goods and services to the customer. A contract may contain variable consideration, including potential payments for both milestone and research and development services. For certain potential milestone payments, the Company estimates the amount of variable consideration by using the most likely amount method. In making this assessment, the Company evaluates factors such as the clinical, regulatory, commercial and other risks that must be overcome to achieve the milestone. Each reporting period the Company re-evaluates the probability of achievement of such variable consideration and any related constraints. Pieris will include variable consideration, without constraint, in the transaction price to the extent it is probable that a significant reversal in the amount of cumulative revenue recognized will not occur when the uncertainty associated with the variable consideration is subsequently resolved. For potential research and development service payments, the Company estimates the amount of variable consideration by using the expected value method, including any approved budget updates arising from additional research or development services. If the contract contains a single performance obligation, the entire transaction price is allocated to the single performance obligation. Contracts that contain multiple performance obligations require an allocation of the transaction price among the performance obligations on a relative standalone selling price basis unless a portion of the transaction price is variable and meets the criteria to be allocated entirely to a performance obligation or to a distinct good or service that forms part of a single performance obligation. The Company allocates the transaction price based on the estimated standalone selling price of the underlying performance obligations or in the case of certain variable consideration to one or more performance obligations. The Company must develop assumptions that require judgment to determine the stand-alone selling price for each performance obligation identified in the contract. The Company utilizes key assumptions to determine the stand-alone selling price, which may include other comparable transactions, pricing considered in negotiating the transaction and the estimated costs to complete the respective performance obligation. Certain variable consideration is allocated specifically to one or more performance obligations in a contract when the terms of the variable consideration relate to the satisfaction of the performance obligation and the resulting amounts allocated to each performance obligation are consistent with the amount the Company would expect to receive for each performance obligation. When a performance obligation is satisfied, revenue is recognized for the amount of the transaction price, excluding estimates of variable consideration that are constrained, that is allocated to that performance obligation on a relative standalone selling price basis. Significant management judgment is required in determining the level of effort required under an arrangement and the period over which the Company is expected to complete its performance obligations under an arrangement. For performance obligations consisting of licenses and other promises, the Company utilizes judgment to assess the nature of the combined performance obligation to determine whether the combined performance obligation is satisfied over time or at a point in time and, if over time, the appropriate method of measuring progress for purposes of recognizing revenue from non- refundable, up-front fees. The Company evaluates the measure of progress each reporting period and, if necessary, adjusts the measure of performance and related revenue recognition. If the license to the Company’s intellectual property is determined to be distinct from the other performance obligations identified in the arrangement, the Company will recognize revenue from non-refundable, up-front fees allocated to the license when the license is transferred to the customer and the customer is able to use and benefit from the license. Revenue recognized under an arrangement involving a participant that is a customer is presented as Customer Revenue. Milestones and Royalties The Company aggregates milestones into four categories: (i) research milestones, (ii) development milestones, (iii) commercial milestones, and (iv) sales milestones. Research milestones are typically achieved upon reaching certain success criteria as defined in each agreement related to developing an Anticalin protein against the specified target. Development milestones are typically reached when a compound reaches a defined phase of clinical research or passes such phase or upon gaining regulatory approvals. Commercial milestones are typically achieved when an approved pharmaceutical product reaches the status for commercial sale, including regulatory approval. Sales milestones are certain defined levels of net sales by the licensee, such as when a product first achieves global sales or annual sales of a specified amount. There is uncertainty that the events to obtain the research and development milestones will be achieved given the nature of clinical development and the stage of the Company’s technology. The Company has thus determined that all research and development milestones will be constrained until it is deemed probable that a significant revenue reversal will not occur. For revenues from research and development milestones, payments will be recognized consistent with the recognition pattern of the performance obligation to which they relate. For arrangements that include sales-based royalties, including milestone payments based on the level of sales, and for which the license is deemed to be the predominant item to which the royalties relate, the Company recognizes revenue at the later of (i) when the related sales occur, or (ii) when the performance obligation to which some or all of the royalty has been allocated has been satisfied (or partially satisfied). Commercial milestones and sales royalties are determined by sales or usage-based thresholds and will be accounted for under the royalty recognition constraint as constrained variable consideration. Contract Balances The Company recognizes a contract asset when the Company transfers goods or services to a customer before the customer pays consideration or before payment is due, excluding any amounts presented as a receivable (i.e., accounts receivable). A contract asset is an entity’s right to consideration in exchange for goods or services that the entity has transferred to a customer. The contract liabilities (i.e., deferred revenue) primarily relate to contracts where the Company has received payment but has not yet satisfied the related performance obligations. In the event of an early termination of a collaboration agreement, any contract liabilities would be recognized in the period in which all Company obligations under the agreement have been fulfilled. Costs to Obtain and Fulfill a Contract with a Customer Certain costs to obtain customer contracts, including success-based fees paid to third-party service providers, and costs to fulfill customer contracts are capitalized in accordance with FASB ASC 340, Other Assets and Deferred Costs , or ASC 340. These costs are amortized to expense on a systemic basis that is consistent with the transfer to the customer of the goods or services to which the asset relates. The Company will expense the amortization of costs to obtain customer contracts to general and administrative expense and costs to fulfill customer contracts to research and development expense. Leases In accordance with ASU No. 2016-2, Leases (Topic 842) , or ASC 842, and for each of the Company’s leases, the following is recognized: (i) a lease liability, which is a lessees obligation to make lease payments arising from a lease, measured on a discounted basis and (ii) a right-of-use asset, which is an asset that represents the lessee’s right to use, or control the use of, a specified asset for the lease term for all leases (with the exception of short-term leases) at the commencement date. The Company determines if an arrangement is a lease at inception. The Company’s contracts are determined to contain a lease within the scope of ASC 842 when all of the following criteria based on the specific circumstances of the arrangement are met: (1) there is an identified asset for which there are no substantive substitution rights; (2) the Company has the right to obtain substantially all of the economic benefits from the identified asset; and (3) the Company has the right to direct the use of the identified asset. At the commencement date, operating lease liabilities and their corresponding right-of-use assets are recorded based on the present value of future lease payments over the expected lease term. The Company’s lease agreements do not provide an implicit rate. As a result, the Company utilizes an estimated incremental borrowing rate to discount lease payments, which is based on the rate of interest the Company would have to pay to borrow a similar amount on a collateralized basis over a similar term and based on observable market data points. Certain adjustments to the right-of-use asset may be required for items such as initial direct costs paid or lease incentives received. Operating lease cost is recognized over the expected term on a straight-line basis. The Company typically only includes an initial lease term in its assessment of a lease agreement. Options to renew a lease are not included in the Company’s assessment unless there is reasonable certainty that the Company will renew. The expected lease term includes noncancelable lease periods and, when applicable, periods covered by an option to extend the lease if the Company is reasonably certain to exercise that option, as well as periods covered by an option to terminate the lease if the Company is reasonably certain not to exercise that option. Assumptions made by the Company at the commencement date are re-evaluated upon occurrence of certain events, including a lease modification. A lease modification results in a separate contract when the modification grants the lessee an additional right of use not included in the original lease and when lease payments increase commensurate with the standalone price for the additional right of use. When a lease modification results in a separate contract, it is accounted for in the same manner as a new lease. Recent Accounting Pronouncement Adopted In December 2019, the FASB issued ASU No. 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes which amends and aims to simplify accounting disclosure requirements regarding a number of topics including intraperiod tax allocation, accounting for deferred taxes when there are changes in consolidation of certain investments, tax basis step up in an acquisition and the application of effective rate changes during interim periods, among other improvements. This standard is effective for fiscal years beginning after December 15, 2020 and was adopted by the Company on January 1, 2021. Adoption of this new standard did not have a material impact on the Company. Recent Accounting Pronouncements Not Yet Adopted In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Statements, or ASU 2016-13. ASU 2016-13 significantly changes the impairment model for most financial assets and certain other instruments. The new standard requires that expected credit losses relating to financial assets measured on an amortized cost basis and available-for-sale debt securities be recorded through an allowance for credit losses. It also limits the amount of credit losses to be recognized for available-for-sale debt securities to the amount by which carrying value exceeds fair value, and requires the reversal of previously recognized credit losses if fair value increases. The allowance for credit losses is a valuation account that is deducted from the amortized cost basis of the financial asset(s) to present the net carrying value at the amount expected to be collected on the financial asset. Subsequently, in November 2018, the FASB issued ASU No. 2018-19, Codification Improvements to Topic 326, Financial Instruments-Credit Losses , which clarifies codification and corrects unintended application of the guidance. In November 2019, the FASB issued ASU No. 2019-11, Codification Improvements to Topic 326, Financial Instruments-Credit Losses , which clarifies or addresses specific issues about certain aspects of ASU 2016-13. In November 2019 the FASB also issued ASU No. 2019-10, Financial Instruments-Credit Losses (Topic 326), Derivatives and Hedging (Topic 815), and Leases (Topic 842): Effective Dates , which delays the effective date of ASU 2016-13 by three years for certain smaller reporting companies such as the Company. The guidance in ASU 2016-13 is effective for the Company for financial statements issued for fiscal years beginning after December 15, 2022 and interim periods within those fiscal years, with early adoption permitted. The Company is still evaluating the impact of the adoption of this standard. The Company has considered other recent accounting pronouncements and concluded that they are either not applicable to the business or that the effect is not expected to be material to the unaudited condensed consolidated financial statements as a result of future adoption.

Revenue

Revenue	3 Months Ended
Revenue	Mar. 31, 2021
Revenue from Contract with Customer [Abstract]
Revenue	Revenue General The Company has not generated revenue from product sales. The Company has generated revenue from contracts with customers and revenue from collaboration agreements, which include upfront payments for licenses or options to obtain licenses, payments for research and development services and milestone payments. The Company recognized revenue from the following strategic partnerships and other license agreements (in thousands): Three Months Ended March 31, 2021 2020 Seagen $ 366 $ 448 AstraZeneca 14,500 2,711 Servier 767 10,102 Total Revenue $ 15,633 $ 13,261 Under the Company’s existing strategic partnerships and other license agreements, the Company could receive the following potential milestone payments (in millions): Research, Development, Regulatory & Commercial Milestones Sales Milestones AstraZeneca $ 1,096 $ 4,275 Servier 236 211 Seagen 754 450 Total potential milestone payments $ 2,086 $ 4,936 Strategic Partnerships Seagen On February 8, 2018, the Company entered into a license and collaboration agreement, or the Seagen Collaboration Agreement, and a non-exclusive Anticalin platform technology license agreement, or the Seagen Platform License, and together with the Seagen Collaboration Agreement, the Seagen Agreements, with Seagen Inc. (formerly Seattle Genetics, Inc.), or Seagen, pursuant to which the parties will develop multiple targeted bispecific IO treatments for solid tumors and blood cancers. Under the terms of the Seagen Agreements, the companies will pursue multiple antibody-Anticalin fusion proteins during the research phase. The Seagen Agreements provide Seagen a base option to select up to three programs for further development. Prior to the initiation of a pivotal trial, the Company may opt into global co-development and U.S. commercialization of the second program and share in global costs and profits on an equal basis. Seagen will solely develop, fund and commercialize the other two programs. Seagen may also decide to select additional candidates from the initial research phase for further development in return for the payment to the Company of additional fees, milestone payments and royalties. The Seagen Platform License grants Seagen a non-exclusive license to certain intellectual property related to the Anticalin platform technology. Upon signing the Seagen Agreements, Seagen paid the Company a $30.0 million upfront fee and an additional $4.9 million was estimated to be paid for research and development services as reimbursement to the Company through the end of the research term. In addition, the Company may receive tiered royalties on net sales up to the low double-digits and up to $1.2 billion in total success-based research, development, commercial and sales milestones payments across the product candidates, depending on the successful development and commercialization of those candidates. If Seagen exercises its option to select additional candidates from the initial research phase for further development, payment to Pieris of additional fees, milestone payments and royalties would result. The term of each of the Seagen Agreements ends upon the expiration of all of Seagen’s payment obligations under each such agreement. The Seagen Collaboration Agreement may be terminated by Seagen on a product-by-product basis for convenience beginning 12 months after its effective date upon 90 days’ notice or, for any program where a pivotal study has been initiated, upon 180 days’ notice. Any program may be terminated at Seagen’s option. If any program is terminated by Seagen after a pre-defined preclinical stage, the Company will have full rights to continue such program. If any program is terminated by Seagen prior to such pre-defined preclinical stage, the Company will have the right to continue to develop such program, but will be obligated to offer a co-development option to Seagen for such program. The Seagen Collaboration Agreement may also be terminated by Seagen or the Company for an uncured material breach by the other party upon 90 days’ notice, subject to extension for an additional 90 days if the material breach relates to diligence obligations and subject, in all cases, to dispute resolution procedures. The Seagen Collaboration Agreement may also be terminated due to the other party’s insolvency and may in certain instances, including for reasons of safety, be terminated on a product-by-product basis. Each party may also terminate the Seagen Agreements if the other party challenges the validity of any patents licensed under the Seagen Agreements, subject to certain exceptions. The Seagen Platform License will terminate upon termination of the Seagen Collaboration Agreement, whether in its entirety or on a product-by-product basis. The Company determined that the Seagen Agreements should be combined and evaluated as a single arrangement under ASC 606 as they were executed on the same date. The arrangement with Seagen provides for the transfer of the following goods or services: (i) three candidate research licenses that each consist of a non-exclusive platform technology license, a co-exclusive candidate research license, and research and development services, (ii) research, development and manufacturing services associated with each candidate research license, (iii) participation on various governance committees, and (iv) two antibody target swap options which were assessed as material rights. Management evaluated all of the promised goods or services within the contract and determined which such goods and services were separate performance obligations. The Company determined that the licenses granted, at arrangement inception, should be combined with the research and development services to be provided for the related antibody target programs as they are not capable of being distinct. A third party would not be able to provide the research and development services due to the specific nature of the intellectual property and knowledge required to perform the services, and Seagen could not benefit from the licenses without the corresponding services. The Company determined that the participation on the various governance committees was distinct as the services could be performed by an outside party. As a result, management concluded there were six separate performance obligations at the inception of the Seagen Agreements: (i) three combined performance obligations, each comprised of a non-exclusive platform technology license, a co-exclusive candidate research license, and research and development services for the first three approved Seagen antibody target programs, (ii) two performance obligations each comprised of a material right for an antibody target swap option for the first and the second approved Seagen antibody target for no additional consideration, and (iii) one performance obligation comprised of the participation on the various governance committees. The Company allocated consideration to the performance obligations based on the relative proportion of their standalone selling prices. The Company developed standalone selling prices for licenses by applying a risk adjusted, net present value, estimate of future potential cash flows approach, which included the cost of obtaining research and development services at arm’s length from a third-party provider, as well as internal full-time equivalent costs to support these services. The Company developed the standalone selling price for committee participation by using management’s estimate of the anticipated participation hours multiplied by a market rate for comparable participants. The transaction price at inception is comprised of fixed consideration of $30.0 million in upfront fees and variable consideration of $4.9 million of estimated research and development services to be reimbursed as research and development occurs through the research term. The $30.0 million upfront fee, which represents the fixed consideration in the transaction price, was allocated to each of the performance obligations based on the relative proportion of their standalone selling prices. The $4.9 million in variable consideration related to the research and development services is allocated specifically to the three target program performance obligations based upon the budgeted services for each program. The amounts allocated to the performance obligations for the three research programs will be recognized on a proportional performance basis through the completion of each respective estimated research term of the individual research programs. The amounts allocated to the material right for the antibody target swap option will be recognized either at the time the material right expires or, if exercised, on a proportional performance basis over the estimated research term for that program. The amounts allocated to the participation on each of the committees will be recognized on a straight-line basis over the anticipated research term for all research programs. As of March 31, 2021, there was $22.8 million of aggregate transaction price allocated to remaining performance obligations. In June 2020, Seagen and the Company entered into amendments to the Seagen Agreements, or together, the Amendment. The Amendment extended the deadline for Seagen to nominate a second and third antibody target. As a result of the Amendment, which completed the obligations under the research term for the first antibody target, the Company recorded as revenue $4.2 million, which was previously recorded as deferred revenue, for the year ended December 31, 2020. The Company also recorded $5.0 million of milestone revenue due from Seagen during the quarter ended June 30, 2020, as it was no longer deemed probable that a significant reversal of revenue would occur, and the remaining performance obligations on first antibody target were completed. On March 24, 2021, the Company announced that Seagen made a strategic equity investment in Pieris, and that the companies had entered into a combination study agreement, or the Combination Study Agreement, to evaluate the safety and efficacy of combining Pieris’ cinrebafusp alfa with Seagen’s tucatinib, a small-molecule tyrosine kinase HER2 inhibitor, for the treatment of gastric cancer patients expressing lower HER2 levels (IHC2+/ISH- & IHC1+) as part of the upcoming phase 2 study to be conducted by Pieris. The companies have also entered into an Amended and Restated License and Collaboration Agreement, or the Second Seagen Amendment, in which their existing IO collaboration agreement has been amended relating to joint development and commercial rights for the second program in the alliance. In connection with the agreements described above, the Company and Seagen also entered into a subscription agreement, or the Seagen Subscription Agreement. Under the Second Seagen Amendment, Pieris’ option to co-develop and co-commercialize the second of three programs in the collaboration has been converted to a co-promotion option in the United States, with Seagen solely responsible for the development and overall commercialization of that program. Pieris will also be entitled to increased royalties from that program in the event that it chooses to exercise the co-promotion option. In connection with the Seagen Subscription Agreement, the Company agreed to issue to Seagen, and Seagen agreed to acquire from the Company, 3,706,174 shares of the Company’s common stock for a total purchase price of $13.0 million, or $3.51 per share, in a private placement transaction pursuant to Section 4(a)(2) of the Securities Act of 1933, as amended. The Seagen Subscription Agreement includes a provision to the effect that Seagen may ask the Company to file a registration statement to register the resale of the shares issued to Seagen, at any time beginning on the date that is 60 calendar days from the date of issuance of the shares. The Company assessed the ASC 606 implications of the Seagen Subscription Agreement and concluded that the fair value of the shares on a per share basis was $2.61 per share as of the transaction date. This resulted in a premium paid for the shares of $3.3 million, all of which was recorded in deferred revenue upon contract execution and allocated to the remaining performance obligations. The Company has concluded that the Combination Study Agreement is within the scope of ASC 808, which defines collaborative arrangements and addresses the presentation of the transactions between the two parties in the income statement and related disclosures. However, ASC 808 does not provide guidance on the recognition of consideration exchanged or accounting for the obligations that may arise between the parties. The Company has concluded that ASC 730, Research and Development , should be applied by analogy. There is no financial statement impact for the Combination Study Agreement as the value of the drug supply received from Seagen is offset against the drug supply cost. Under the Seagen Agreements, the Company is eligible to receive other various research, development, commercial and sales milestones. There is uncertainty that the events to obtain the research and development milestones will be achieved given the nature of clinical development and the stage of the Company’s technology. With the exception of the previously discussed achieved milestone, the Company has determined that all other research and development milestones will be constrained until it is deemed probable that a significant revenue reversal will not occur. As of March 31, 2021, there were $10.2 million and $9.4 million of current and non-current deferred revenue, respectively, related to the Seagen Agreements. AstraZeneca On May 2, 2017, the Company entered into a license and collaboration agreement, or the AstraZeneca Collaboration Agreement, and a non-exclusive Anticalin platform technology license agreement, or AstraZeneca Platform License, and together with the AstraZeneca Collaboration Agreement, the AstraZeneca Agreements, with AstraZeneca, which became effective on June 10, 2017, following expiration of the waiting period under the Hart-Scott-Rodino Antitrust Improvements Act of 1976. Under the AstraZeneca Agreements, the parties will advance several novel inhaled Anticalin proteins. In addition to the Company’s lead inhaled drug candidate, PRS-060/AZD1402, or the AstraZeneca Lead Product, the Company and AstraZeneca will also collaborate to progress four additional novel Anticalin proteins against undisclosed targets for respiratory diseases, or the AstraZeneca Collaboration Products, and together with the AstraZeneca Lead Product, the AstraZeneca Products. The Company is responsible for advancing the AstraZeneca Lead Product through its phase 1 study, with the associated costs funded by AstraZeneca. The parties will collaborate thereafter to conduct a phase 2a study in asthma patients, with AstraZeneca continuing to fund development costs. After completion of a phase 2a study, Pieris has the option to co-develop the AstraZeneca Lead Product and also has a separate option to co-commercialize the AstraZeneca Lead Product in the United States. For the AstraZeneca Collaboration Products, the Company will be responsible for the initial discovery of the novel Anticalin proteins, after which AstraZeneca will take the lead on continued development of the AstraZeneca Collaboration Products. The Company has the option to co-develop two of the four AstraZeneca Collaboration Products beginning at a pre-defined preclinical stage and would also have the option to co-commercialize these two programs in the United States, while AstraZeneca will be responsible for development and commercialization of the other programs worldwide. The term of each of the AstraZeneca Agreements ends upon the expiration of all of AstraZeneca’s payment obligations under such agreement. The AstraZeneca Collaboration Agreement may be terminated by AstraZeneca in its entirety for convenience beginning 12 months after its effective date upon 90 days’ notice or, if the Company has obtained marketing approval for the marketing and sale of a product, upon 180 days’ notice. Each program may be terminated at AstraZeneca’s option; if any program is terminated by AstraZeneca, the Company will have full rights to such program. The AstraZeneca Collaboration Agreement may also be terminated by AstraZeneca or the Company for material breach upon 180 days’ notice of a material breach (or 30 days with respect to payment breach), provided that the applicable party has not cured such breach by the permitted cure period (including an additional 180 days if the breach is not susceptible to cure during the initial 180-day period) and dispute resolution procedures specified in the agreement have been followed. The AstraZeneca Collaboration Agreement may also be terminated due to the other party’s insolvency and may in certain instances be terminated on a product-by-product and/or country-by-country basis. Each party may also terminate an AstraZeneca Agreement if the other party challenges the validity of patents related to certain intellectual property licensed under such AstraZeneca Agreement, subject to certain exceptions for infringement suits, acquisitions and newly-acquired licenses. The AstraZeneca Platform License will terminate upon termination of the AstraZeneca Collaboration Agreement, on a product-by-product and/or country-by-country basis. At inception, AstraZeneca is granted the following licenses: (i) research and development license for the AstraZeneca Lead Product, (ii) commercial license for the AstraZeneca Lead Product, (iii) individual research licenses for each of the four AstraZeneca Collaboration Products, (iv) individual commercial licenses for each of the four AstraZeneca Collaboration Products, and (v) individual non-exclusive platform technology licenses for the AstraZeneca Lead Product and the four AstraZeneca Collaboration Products. AstraZeneca will be granted individual development licenses for each of the four AstraZeneca Collaboration Products upon completion of the initial discovery of Anticalin proteins. The collaboration will be managed on an overall basis by a Joint Steering Committee, or JSC, formed by an equal number of representatives from the Company and AstraZeneca. In addition to the JSC, the AstraZeneca Collaboration Agreement also requires each party to designate an alliance manager to facilitate communication and coordination of the parties’ activities under the agreement, and further requires participation of both parties on a joint development committee, or JDC, and a commercialization committee. The responsibilities of these committees vary, depending on the stage of development and commercialization of each product. Under the AstraZeneca Agreements, the Company received an upfront, non-refundable payment of $45.0 million. In addition, the Company will receive payments to conduct a phase 1 clinical study for the AstraZeneca Lead Product. The Company is also eligible to receive research, development, commercial, sales milestone payments and royalty payments. The Company may receive tiered royalties on sales of potential products commercialized by AstraZeneca and for co-developed products, gross margin share on worldwide sales equal to the Company’s level of committed investment. The Company determined that the AstraZeneca Agreements should be combined and evaluated as a single arrangement under ASC 606 as they were executed on the same date. The arrangement with AstraZeneca, including the impact of any modifications, provides for the transfer of the following goods and services: (i) five non-exclusive platform technology licenses, (ii) research and development license for the AstraZeneca Lead Product, (iii) commercial license for the AstraZeneca Lead Product, (iv) development and manufacturing services for the AstraZeneca Lead Product (or the phase 1 services), (v) technology transfer services for the AstraZeneca Lead Product, (vi) research services related to the AstraZeneca Lead Product, (vii) participation on each of the committees, (viii) four research licenses for the AstraZeneca Collaboration Products, (ix) four commercial licenses for the AstraZeneca Collaboration Products, (x) research services for the AstraZeneca Collaboration Products and (xi) certain phase 2a services for the AstraZeneca Lead Product. Additionally, as the development licenses on the four AstraZeneca Collaboration Products may be granted at a discount in the future, the Company determined such discounts should be assessed as material rights at inception. Management evaluated all of the promised goods or services within the contract and determined which such goods and services were separate performance obligations. The Company determined that the licenses granted for the AstraZeneca Lead Product at the inception of the arrangement should be combined with the research services related to the AstraZeneca Lead Product and that the licenses granted for the AstraZeneca Collaboration Products should be combined with the research services for the AstraZeneca Collaboration Products, as the licenses are not capable of being distinct. A third party would not be able to provide the research and development services, due to the specific nature of the intellectual property and knowledge required to perform the services, and AstraZeneca could not benefit from the licenses without the corresponding services. The Company also determined that each of the phase 1 services and the phase 2a services for the AstraZeneca Lead Product were distinct and that the participation on the various committees was also distinct, as all of the phase 1 services, phase 2a services and the committee services could be performed by an outside party. The Company determined that the commercial licenses for the AstraZeneca Collaboration Products granted at the inception of the arrangement should be combined with the development licenses for the AstraZeneca Collaboration Products as the company would not benefit from the commercial license without the ability to develop each product. As a result, management concluded that there were 16 performance obligations: (i) combined performance obligation comprised of a non-exclusive platform technology license, research and development license, and commercial licenses for the AstraZeneca Lead Product and research services for the AstraZeneca Lead Product, (ii) combined performance obligation comprised of development and manufacturing services, and technology transfer services for the AstraZeneca Lead Product, (iii) committee participation, (iv-vii) four combined performance obligations each comprised of a non-exclusive platform technology license, research licenses, and research services for each AstraZeneca Collaboration Product, (viii-xi) four performance obligations comprised of a material right to acquire the development licenses granted for the AstraZeneca Collaboration Products, (xii-xv) four performance obligations comprised of the commercial licenses granted for the AstraZeneca Collaboration Products and (xvi) phase 2a services. The Company allocated consideration to the performance obligations based on the relative proportion of their standalone selling prices. The Company developed standalone selling prices for licenses and corresponding research services by applying a risk adjusted, net present value, estimate of future potential cash flow approach, which included the cost of obtaining research services at arm’s length from a third-party provider, as well as internal full-time equivalent costs to support these services. The Company developed its standalone selling price for development and manufacturing services and technology transfer services for the AstraZeneca Lead Product using estimated internal and external costs to be incurred. The Company developed its standalone selling price for committee participation by using management’s estimate of the anticipated participation hours multiplied by a market rate for comparable participants. The Company developed its standalone selling price for the commercial licenses and material rights granted on the development licenses by probability weighting multiple cash flow scenarios using the income approach. The transaction price was comprised of fixed consideration of $45.0 million in upfront fees and variable consideration of (i) $14.2 million in estimated phase 1 services, (ii) $12.5 million in milestone payments achieved upon the initiation of a phase 1 study in December 2017, and (iii) $4.7 million in estimated phase 2a services. The $45.0 million upfront fee, which represents the fixed consideration in the transaction price, was allocated to each of the performance obligations based on the relative proportion of their standalone selling prices. Variable consideration of $14.2 million is related to the phase 1 services and will be allocated entirely to the performance obligation to which they relate. Variable consideration of $12.5 million related to the phase 1 trial milestone was allocated by relative selling price to the combined performance obligation comprised of a non-exclusive platform technology license, research and development license and commercial licenses for the AstraZeneca Lead Product and research services for the AstraZeneca Lead Product, and the combined performance obligation comprised of development and manufacturing services and technology transfer services for the AstraZeneca Lead Product performance obligations. Variable consideration of $4.7 million for phase 2a services was allocated specifically to the related performance obligation. The amounts allocated to the license performance obligation for the AstraZeneca Lead Product and the four performance obligations for the four research licenses for AstraZeneca Collaboration Products will be recognized on a proportional performance basis as the activities are conducted over the life of the arrangement. The amounts allocated to the performance obligation for phase 1 services, technology transfer services for the AstraZeneca Lead Product will be recognized on a proportional performance basis over the estimated term of development through phase 2a study. The amounts allocated to the performance obligation for phase 2a services for the AstraZeneca Lead Product will be recognized on a proportionate performance basis over an estimated term of 12 months. The amounts allocated to the performance obligation for participation on each of the committees will be recognized on a straight-line basis over the expected term of development of the AstraZeneca Lead Product and the AstraZeneca Collaboration Products. The term of performance is approximately five years. The amounts allocated to the four performance obligations for the material rights to acquire a development license and the four performance obligations for commercial licenses for the AstraZeneca Collaboration Products will be recognized upon exercise of the specific material right and delivery of each of the development licenses. As of March 31, 2021, there was $23.8 million of aggregate transaction price allocated to remaining performance obligations. Additionally, the Company evaluated payments required to be made between both parties as a result of the shared development costs of the AstraZeneca Lead Product and the two AstraZeneca Collaboration Products for which the Company has a co-development option. The Company will classify payments made as a reduction of revenue and will classify payments received as revenue in the period they are earned. Under the AstraZeneca Agreements, the Company is eligible to receive various research, development, commercial and sales milestones. There is uncertainty that the events to obtain the research and development milestones will be achieved given the nature of clinical development and the stage of the Company’s technology. The Company has thus determined that all research and development milestones, other than the phase 1 initiation milestone achieved in December 2017 and included in the impact of adoption of ASC 606, will be constrained until it is deemed probable that a significant revenue reversal will not occur. On March 29, 2021, the Company and AstraZeneca entered into (1) Amendment No. 1 to the Non-exclusive Anticalin ® Platform License Agreement dated May 2, 2017 and (2) Amendment No. 2 to the License and Collaboration Agreement dated May 2, 2017, as previously amended by Amendment No. 1 dated September 14, 2020, collectively, the Amended Collaboration Agreement. Under the Amended Collaboration Agreement, the parties agreed to restructure certain commercial economics for the AZD1402/PRS-060 program by increasing potential sales milestones and reducing potential sales royalties, while fundamentally maintaining the overall value split between AstraZeneca and the Company. In connection with the Amended Collaboration Agreement, the Company and AstraZeneca entered into a Subscription Agreement pursuant to which the Company agreed to issue to AstraZeneca, and AstraZeneca agreed to acquire from the Company, 3,584,230 shares of the Company’s common stock for a total purchase price of $10.0 million, or $2.79 per share, in a private placement transaction pursuant to Section 4(a)(2) of the Securities Act. The Subscription Agreement closed on April 1, 2021 and includes a requirement that the Company file a registration statement to register the resale of the shares issued to AstraZeneca within 60 calendar days of the issuance of the shares. The Company assessed the payment under ASC 606 and concluded that the fair value of the shares on a per share basis was $2.60 per share as of the transaction date. This resulted in a premium paid for the shares of $0.7 million, of which $0.1 million was recognized as revenue as of March 31, 2021. Also in March 2021, the Company earned a $13.0 million milestone from AstraZeneca related to the initiation of the phase 2a study for PRS-060/AZD1402. The Company assessed the milestone payment under ASC 606 and determined that there no longer existed a constraint on the milestone as the performance obligation related to the phase 2a study was fully satisfied. Therefore, the Company realized the full $13.0 million as milestone revenue for the three months ended March 31, 2021. As of March 31, 2021, there were $0.9 million and $18.1 million of current and non-current deferred revenue, respectively, related to the AstraZeneca Agreements. The Company incurred $1.6 million of third-party success fees to obtain the contract with AstraZeneca. Upon adoption of ASC 606, the Company capitalized $1.1 million in accordance with ASC 340. As of March 31, 2021, the remaining balance of the asset recognized from transaction costs to obtain the AstraZeneca contract was $0.7 million. Amortization during the three months ended March 31, 2021 and 2020 was de minimis. Servier On January 4, 2017, the Company entered into a license and collaboration agreement, or Servier Collaboration Agreement, and a non-exclusive Anticalin platform license agreement, or Servier Platform License, and together with the Servier Collaboration Agreement, the Servier Agreements, with Les Laboratoires Servier and Institut de Recherches Internationales Servier, or Servier, pursuant to which the Company and Servier agreed to initially pursue five bispecific therapeutic programs. Five committed programs were initially defined, which may combine antibodies from the Servier portfolio with one or more Anticalin proteins based on the Company’s proprietary platform to generate innovative IO bispecific drug candidates, or the Collaboration Products. The collaboration may be expanded by up to three additional therapeutic programs. The Company had the option to co-develop and retain commercial rights in the United States for PRS-332, the initial lead program under the collaboration, or the Initial Lead, and has a similar option on up to three additional programs, or the Co-Development Collaboration Products, while Servier will be responsible for development and commercialization of the other programs worldwide, or the Servier Worldwide Collaboration Products. Each party is responsible for an agreed upon percentage of shared costs, as set forth in the budget for the collaboration plan, and as further discussed below. The Co-Development Collaboration Products may be jointly developed, according to a collaboration plan, through marketing approval from the U.S. Food and Drug Administration or the European Medicines Agency. Servier Worldwide Collaboration Products may be jointly developed, according to a collaboration plan, throu

Cash, cash equivalents and inve

Cash, cash equivalents and investments	3 Months Ended
Cash, cash equivalents and investments	Mar. 31, 2021
Cash and Cash Equivalents [Abstract]
Cash, cash equivalents and investments	Cash, cash equivalents and investments As of March 31, 2021 and December 31, 2020, cash equivalents were $49.7 million and $64.0 million, respectively, and are comprised of money market accounts, all of which are Level 1 investments. The Company did not hold any Level 2 or 3 investments as of March 31, 2021 and did not have any transfers of investment between level for the three months ended March 31, 2021. The Company did not record any realized gains or losses from the maturity of available-for-sale securities during the three months ended March 31, 2021. The Company recorded realized gains of $0.2 million from the maturity of available-for-sale securities for the three months ended March 31, 2020.

Property and equipment, net

Property and equipment, net	3 Months Ended
Property and equipment, net	Mar. 31, 2021
Property, Plant and Equipment [Abstract]
Property and equipment, net	Property and equipment, net Property and equipment are summarized as follows (in thousands): March 31, December 31, 2021 2020 Laboratory furniture and equipment $ 10,729 $ 11,188 Office furniture and equipment 2,030 2,120 Computer equipment 384 394 Leasehold improvements 13,542 14,159 Property and equipment, cost 26,685 27,861 Accumulated depreciation (6,173) (5,815) Property and equipment, net $ 20,512 $ 22,046

Accrued Expenses

Accrued Expenses	3 Months Ended
Accrued Expenses	Mar. 31, 2021
Payables and Accruals [Abstract]
Accrued Expenses	Accrued Expenses Accrued expenses and other current liabilities consisted of the following (in thousands): March 31, December 31, 2021 2020 Accrued accounts payable $ 3,466 $ 1,220 Research and development fees 2,066 2,001 Compensation expense 1,479 2,759 Lease liabilities 987 1,030 Accrued license obligations 799 358 Audit and tax fees 429 128 Other current liabilities 336 235 Total $ 9,562 $ 7,731

Net Loss per Share

Net Loss per Share	3 Months Ended
Net Loss per Share	Mar. 31, 2021
Earnings Per Share [Abstract]
Net Loss per Share	Net Loss per Share Basic net loss per share is calculated by dividing net income loss by the weighted average shares outstanding during the period, without consideration for common stock equivalents. Diluted net loss per share is calculated by adjusting weighted average shares outstanding for the dilutive effect of common stock equivalents outstanding for the period, determined using the treasury-stock and if-converted methods. For purposes of the diluted net loss per share calculation, preferred stock, stock options and warrants are considered to be common stock equivalents but have been excluded from the calculation of diluted net loss per share, as their effect would be anti-dilutive for all periods presented. Therefore, basic and diluted net loss per share were the same for all periods presented. For the three months ended March 31, 2021 and 2020, and as calculated using the treasury stock method, approximately 38.6 million and 34.9 million of weighted average shares, respectively, were excluded from the calculation of diluted weighted average shares outstanding as their effect was antidilutive.

Stockholders' Equity

Stockholders' Equity	3 Months Ended
Stockholders' Equity	Mar. 31, 2021
Equity [Abstract]
Stockholders' Equity	Stockholders’ Equity The Company had 300,000,000 shares authorized and 59,718,989 and 56,002,815 shares of common stock issued and outstanding as of March 31, 2021 and December 31, 2020, respectively, with a par value of $0.001 per share. The Company had 10,000,000 shares authorized and 14,429 shares of preferred stock issued and outstanding as of March 31, 2021. The Company had 10,000,000 shares authorized and 14,429 shares of preferred stock issued and outstanding as of December 31, 2020. Preferred stock has a par value of $0.001 per share, and consists of the following: • Series A Convertible, 2,907 shares issued and outstanding at March 31, 2021 and December 31, 2020, respectively. • Series B Convertible, 5,000 shares issued and outstanding at March 31, 2021 and December 31, 2020, respectively. • Series C Convertible, 3,522 shares issued and outstanding at March 31, 2021 and December 31, 2020, respectively. • Series D Convertible, 3,000 shares issued and outstanding at March 31, 2021 and December 31, 2020, respectively. 2020 Employee, Director and Consultant Equity Incentive Plan At the Annual Shareholder Meeting, held on June 23, 2020, the shareholders approved the 2020 Employee, Director and Consultant Equity Incentive Plan, or the 2020 Plan. The 2020 Plan permits the Company to issue up to 3,500,000 shares of common stock pursuant to awards granted under the 2020 Plan. Upon approval of the 2020 Plan, the 2019 Employee, Director and Consultant Equity Incentive Plan, or the 2019 Plan, was terminated; all unissued options were canceled and no additional awards will be made thereunder. All outstanding awards under the 2019 Plan will remain in effect and any awards forfeited from the outstanding awards will be allocated back into the 2020 Plan. There were approximately 1,579,678 shares remaining and available for grant under the 2019 Plan that terminated upon approval of the 2020 Plan. Series D Preferred Stock Conversion On March 31, 2020, the Company and certain entities affiliated with Biotechnology Value Fund, L.P., or BVF, entered into an exchange agreement pursuant to which, on April 1, 2020, BVF exchanged an aggregate of 3,000,000 shares of the Company’s common stock owned by BVF for an aggregate of 3,000 shares of Series D Preferred Stock. The Company designated 3,000 shares of its authorized and unissued preferred stock as Series D Preferred Stock and filed a Certificate of Designation of Series D Convertible Preferred Stock of Pieris Pharmaceuticals, Inc., or the Series D Certificate of Designation, with the Nevada Secretary of State. Each share of Series D Preferred Stock is convertible into 1,000 shares of Common Stock (subject to adjustment as provided in the Series D Certificate of Designation) at any time at the option of the holder, provided that the holder is prohibited from converting the Series D Preferred Stock into shares of Common Stock if, as a result of such conversion, the holder, together with its affiliates, would own more than 9.99% of the total number of shares of Common Stock then issued and outstanding, or the Beneficial Ownership Limitation. The holder may reset the Beneficial Ownership Limitation to a higher or lower number (not to exceed 19.99% of the total number of Common Shares issued and outstanding immediately after giving effect to a conversion) upon providing written notice to the Company. Any such notice providing for an increase to the Beneficial Ownership Limitation will be effective 61 days after delivery to the Company. In the event of the Company’s liquidation, dissolution, or winding up, subject to the rights of holders of Senior Securities (defined below), holders of Series D Preferred Stock are entitled to receive a payment equal to $0.001 per share of Series D Preferred Stock before any proceeds are distributed to the holders of Common Stock and Junior Securities (defined below) and pari passu with any distributions to the holders of the Series A Preferred Stock, Series B Preferred Stock and Series C Preferred Stock, plus an additional amount equal to any dividends declared but unpaid on such shares. However, if the assets of the Company are insufficient to comply with the preceding sentence, then all remaining assets of the Company shall be distributed ratably to holders of the shares of the Series D Preferred Stock and Parity Securities (defined below). Shares of Series D Preferred Stock generally have no voting rights, except as required by law and except that the consent of holders of a majority of the then outstanding Series D Preferred Stock is required to amend the terms of the Series D Certificate of Designation. Holders of Series D Preferred Stock are entitled to receive any dividends payable to holders of Common Stock, and rank: • senior to all of the Common Stock; • senior to any class or series of capital stock of the Company created after the designation of the Series D Preferred Stock specifically ranking by its terms junior to the Series D Preferred Stock, or the “Junior Securities; • on parity with all shares of Series A Preferred Stock, Series B Preferred Stock, Series C Preferred Stock and any class or series of capital stock of the Company created after the designation of the Series D Preferred Stock specifically ranking by its terms on parity with the Series D Preferred Stock, or the Parity Securities; and • junior to any class or series of capital stock of the Company created after the designation of the Series D Preferred Stock specifically ranking by its terms senior to the Series D Preferred Stock, or the Senior Securities, in each case, as to distributions of assets upon the Company’s liquidation, dissolution or winding up whether voluntarily or involuntarily and/or the right to receive dividends. Open Market Sales Agreement

Leases

Leases	3 Months Ended
Leases	Mar. 31, 2021
Leases [Abstract]
Leases	Leases The Company currently leases office space in Boston, Massachusetts. In August 2015, the Company entered into a sublease to lease approximately 3,950 square feet. The sublease expires on February 27, 2022 or such earlier date pursuant to the termination provisions of the sublease. The Company also leased approximately 19,000 square feet of office and laboratory space in Freising, Germany under four agreements, or the Freising Leases, including three leases for space on three floors of the same building and a letter agreement for additional conference room space within the building. The Freising Leases expired on March 31, 2020. In October 2018, Pieris GmbH entered into a new lease for office and laboratory space located in Hallbergmoos, Germany, or the Hallbergmoos Lease. Pieris GmbH moved its operations, formerly conducted in Freising, Germany, to the Hallbergmoos facility in February 2020. Under the Hallbergmoos Lease, Pieris GmbH will rent approximately 105,000 square feet, of which approximately 98,400 square feet were delivered by the lessor in February 2020 and approximately 5,100 square feet were delivered by the lessor in May 2020. An additional approximately 22,300 square feet is expected to be delivered by the lessor by October 2024. Pieris GmbH has a first right of refusal to lease an additional approximate 13,400 square feet. The Hallbergmoos Lease provides for an initial rental term of 12.5 years which commenced in February 2020 when the leased property was delivered to Pieris GmbH. Pieris GmbH also has an option to extend the Hallbergmoos Lease for two additional 60-month periods. The Company is not reasonably certain to exercise the option to extend the lease expiration beyond its current expiration date. Pieris GmbH may sublease space within the leased property with lessor’s consent, which may not be unreasonably withheld. Monthly base rent for the initial 105,000 square feet of the leased property, including parking spaces, will total approximately $0.2 million per month, which amount shall be adjusted starting on the second anniversary of the commencement date by an amount equal to the German consumer price index. In addition to the base rent, Pieris GmbH is also responsible for certain administrative and operational costs in accordance with the Hallbergmoos Lease. Pieris GmbH provided a security deposit of $0.8 million as required by the Hallbergmoos Lease. The Company will serve as a guarantor for the Hallbergmoos Lease. The Hallbergmoos Lease included $11.5 million of tenant improvements allowance for normal tenant improvements, for which construction began in March 2019. The Company capitalized the leasehold incentives which are included in Property and equipment, net on the Condensed Consolidated Balance Sheet and are amortized on a straight-line basis over the shorter of the useful life or the remaining lease term. The lease incentive allowance was also factored in as a reduction to the right-of-use asset upon the adoption of ASC 842. The following table summarizes operating lease costs included in operating expenses (in thousands): Three Months Ended March 31, 2021 2020 Operating lease costs $ 377 $ 404 Variable lease costs (1) 182 188 Total lease cost $ 559 $ 592 (1) Variable lease costs include certain additional charges for operating costs, including insurance, maintenance, taxes, utilities, and other costs incurred, which are billed based on both usage and as a percentage of the Company’s share of total square footage. The following table summarizes the weighted-average remaining lease term and discount rate: As of March 31, 2021 Weighted-average remaining lease term (years) 11.2 Weighted-average discount rate 10.5 % Cash paid for amounts included in the measurement of the lease liabilities was $0.7 million and $0.3 million for the three months ended March 31, 2021 and 2020. As of March 31, 2021, the maturities of the Company’s operating lease liabilities and future minimum lease payments were as follows (in thousands): Total 2021 $ 1,910 2022 2,349 2023 2,314 2024 2,314 2025 2,314 Thereafter 15,236 Total undiscounted lease payments 26,437 Less: present value adjustment (26,437) Present value of lease liabilities $ —

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	3 Months Ended
Summary of Significant Accounting Policies (Policies)	Mar. 31, 2021
Accounting Policies [Abstract]
Basis of Presentation	The accompanying condensed consolidated financial statements of Pieris Pharmaceuticals, Inc. and its wholly-owned subsidiaries were prepared in accordance with U.S. GAAP. The condensed consolidated financial statements include the accounts of all subsidiaries. All intercompany balances and transactions have been eliminated.
Use of Estimates	The preparation of the financial statements in accordance with U.S. GAAP requires management to make estimates, judgments and assumptions that affect the reported amounts of assets, liabilities, revenues, expenses and the related disclosures at the date of the financial statements and during the reporting period. Significant estimates are used for, but are not limited to, revenue recognition; deferred tax assets, deferred tax liabilities and valuation allowances; determination of the incremental borrowing rate to calculate right-of-use assets and lease liabilities; beneficial conversion features; fair value of stock options, preferred stock, and warrants; and various accruals. Management evaluates its estimates on an ongoing basis. Actual results and outcomes could differ materially from management’s estimates, judgments and assumptions.
Cash, Cash Equivalents and Investments	The Company determines the appropriate classification of its investments at the time of purchase. All liquid investments with original maturities of 90 days or less from the purchase date and for which there is an active market are considered to be cash equivalents. The Company’s investments are comprised of money market, asset backed securities, government treasuries and corporate bonds that are classified as available-for-sale in accordance with FASB Accounting Standards Codification, or ASC, 320, Investments—Debt and Equity Securities . The Company classifies investments available to fund current operations as current assets on its balance sheets. Available-for-sale investments are recorded at fair value, with unrealized gains or losses included in accumulated other comprehensive loss on the Company’s balance sheets. Realized gains and losses are determined using the specific identification method and are included as a component of other income.
Concentration of Credit Risk and Off-Balance Sheet Risk	The Company has no financial instruments with off-balance sheet risk such as foreign exchange contracts, option contracts or other foreign hedging arrangements. Financial instruments that subject Pieris to concentrations of credit risk include cash and cash equivalents, investments, and accounts receivable. The Company’s cash, cash equivalents, and investments are held in accounts with financial institutions that management believes are creditworthy. The Company’s investment policy includes guidelines on the quality of the institutions and financial instruments and defines allowable investments that the Company believes minimizes the exposure to concentration of credit risk. The Company has not experienced any credit losses in such accounts and does not believe it is exposed to any significant credit risk on these funds. Accounts receivable primarily consist of amounts due under strategic partnership and other license agreements with major multi-national pharmaceutical companies for which the Company does not obtain collateral.
Fair Value Measurement	The Company is required to disclose information on all assets and liabilities reported at fair value that enables an assessment of the inputs used in determining the reported fair values. FASB ASC Topic 820, Fair Value Measurement and Disclosures , established a hierarchy of inputs used in measuring fair value that maximizes the use of observable inputs and minimizes the use of unobservable inputs by requiring that the observable inputs be used when available. Observable inputs are inputs that market participants would use in pricing the financial instrument based on market data obtained from sources independent of the Company. Unobservable inputs are inputs that reflect the Company’s assumptions about the inputs that market participants would use in pricing the financial instrument and are developed based on the best information available in the circumstances. The fair value hierarchy applies only to the valuation inputs used in determining the reported or disclosed fair value of the financial instruments and is not a measure of the investment credit quality. Fair value measurements are classified and disclosed in one of the following three categories: • Level 1 inputs are quoted prices in active markets for identical assets or liabilities that the reporting entity has the ability to access at the measurement date. • Level 2 utilizes quoted market prices in markets that are not active, broker or dealer quotations or alternative pricing sources with reasonable levels of price transparency. • Level 3 inputs are unobservable inputs for the asset or liability in which there is little, if any, market activity for the asset or liability at the measurement date. To the extent that valuation is based on models or inputs that are less observable or unobservable in the market, the determination of fair value requires more judgment. Accordingly, the degree of judgment exercised by the Company in determining fair value is greatest for instruments categorized in Level 3. A financial instrument’s level within the fair value hierarchy is based on the lowest level of any input that is significant to the fair value measurement. Financial instruments measured at fair value on a recurring basis include cash equivalents (see Note 4).
Revenue Recognition	The Company has entered into several licensing agreements with collaboration partners for the development of Anticalin therapeutics against a variety of targets. The terms of these agreements provide for the transfer of multiple goods or services which may include: (i) licenses, or options to obtain licenses, to the Company’s Anticalin technology and/or specific programs and (ii) research and development activities to be performed on behalf of or with a collaborative partner. Payments to Pieris under these agreements may include upfront fees (which include license and option fees), payments for research and development activities, payments based upon the achievement of certain milestones and royalties on product sales. There are no performance, cancellation, termination or refund provisions in any of the arrangements that could result in material financial consequences to Pieris. Collaborative Arrangements The Company considers the nature and contractual terms of an arrangement and assesses whether the arrangement involves a joint operating activity pursuant to which it is an active participant and exposed to significant risks and rewards with respect to the arrangement. If the Company is an active participant and exposed to the significant risks and rewards with respect to the arrangement, it accounts for these arrangements pursuant to ASC 808, Collaborative Arrangements , or ASC 808, and applies a systematic and rational approach to recognize revenue. The Company classifies payments received as revenue and payments made as a reduction of revenue in the period in which they are earned. Revenue recognized under a collaborative arrangement involving a participant that is not a customer is presented as Collaboration Revenue in the Statement of Operations. Revenue from Contracts with Customers In accordance with ASC 606, revenue is recognized when a customer obtains control of promised goods or services. The amount of revenue recognized reflects the consideration to which the Company expects to be entitled in exchange for these goods and services. To achieve this core principle, the Company applies the following five steps: 1) identify the customer contract; 2) identify the contract’s performance obligations; 3) determine the transaction price; 4) allocate the transaction price to the performance obligations; and 5) recognize revenue when or as a performance obligation is satisfied. The Company evaluates all promised goods and services within a customer contract and determines which of such goods and services are separate performance obligations. This evaluation includes an assessment of whether the good or service is capable of being distinct and whether the good or service is separable from other promises in the contract. In assessing whether promised goods or services are distinct, the Company considers factors such as the stage of development of the underlying intellectual property and the capabilities of the customer to develop the intellectual property on their own or whether the required expertise is readily available. Licensing arrangements are analyzed to determine whether the promised goods or services, which often include licenses, research and development services and governance committee services, are distinct or whether they must be accounted for as part of a combined performance obligation. If the license is considered not to be distinct, the license would then be combined with other promised goods or services as a combined performance obligation. If the Company is involved in a governance committee, it assesses whether its involvement constitutes a separate performance obligation. When governance committee services are determined to be separate performance obligations, the Company determines the fair value to be allocated to this promised service. Certain contracts contain optional and additional items, which are considered marketing offers and are accounted for as separate contracts with the customer if such option is elected by the customer, unless the option provides a material right which would not be provided without entering into the contract. An option that is considered a material right is accounted for as a separate performance obligation. The transaction price is determined based on the consideration to which the Company will be entitled in exchange for transferring goods and services to the customer. A contract may contain variable consideration, including potential payments for both milestone and research and development services. For certain potential milestone payments, the Company estimates the amount of variable consideration by using the most likely amount method. In making this assessment, the Company evaluates factors such as the clinical, regulatory, commercial and other risks that must be overcome to achieve the milestone. Each reporting period the Company re-evaluates the probability of achievement of such variable consideration and any related constraints. Pieris will include variable consideration, without constraint, in the transaction price to the extent it is probable that a significant reversal in the amount of cumulative revenue recognized will not occur when the uncertainty associated with the variable consideration is subsequently resolved. For potential research and development service payments, the Company estimates the amount of variable consideration by using the expected value method, including any approved budget updates arising from additional research or development services. If the contract contains a single performance obligation, the entire transaction price is allocated to the single performance obligation. Contracts that contain multiple performance obligations require an allocation of the transaction price among the performance obligations on a relative standalone selling price basis unless a portion of the transaction price is variable and meets the criteria to be allocated entirely to a performance obligation or to a distinct good or service that forms part of a single performance obligation. The Company allocates the transaction price based on the estimated standalone selling price of the underlying performance obligations or in the case of certain variable consideration to one or more performance obligations. The Company must develop assumptions that require judgment to determine the stand-alone selling price for each performance obligation identified in the contract. The Company utilizes key assumptions to determine the stand-alone selling price, which may include other comparable transactions, pricing considered in negotiating the transaction and the estimated costs to complete the respective performance obligation. Certain variable consideration is allocated specifically to one or more performance obligations in a contract when the terms of the variable consideration relate to the satisfaction of the performance obligation and the resulting amounts allocated to each performance obligation are consistent with the amount the Company would expect to receive for each performance obligation. When a performance obligation is satisfied, revenue is recognized for the amount of the transaction price, excluding estimates of variable consideration that are constrained, that is allocated to that performance obligation on a relative standalone selling price basis. Significant management judgment is required in determining the level of effort required under an arrangement and the period over which the Company is expected to complete its performance obligations under an arrangement. For performance obligations consisting of licenses and other promises, the Company utilizes judgment to assess the nature of the combined performance obligation to determine whether the combined performance obligation is satisfied over time or at a point in time and, if over time, the appropriate method of measuring progress for purposes of recognizing revenue from non- refundable, up-front fees. The Company evaluates the measure of progress each reporting period and, if necessary, adjusts the measure of performance and related revenue recognition. If the license to the Company’s intellectual property is determined to be distinct from the other performance obligations identified in the arrangement, the Company will recognize revenue from non-refundable, up-front fees allocated to the license when the license is transferred to the customer and the customer is able to use and benefit from the license. Revenue recognized under an arrangement involving a participant that is a customer is presented as Customer Revenue. Milestones and Royalties The Company aggregates milestones into four categories: (i) research milestones, (ii) development milestones, (iii) commercial milestones, and (iv) sales milestones. Research milestones are typically achieved upon reaching certain success criteria as defined in each agreement related to developing an Anticalin protein against the specified target. Development milestones are typically reached when a compound reaches a defined phase of clinical research or passes such phase or upon gaining regulatory approvals. Commercial milestones are typically achieved when an approved pharmaceutical product reaches the status for commercial sale, including regulatory approval. Sales milestones are certain defined levels of net sales by the licensee, such as when a product first achieves global sales or annual sales of a specified amount. There is uncertainty that the events to obtain the research and development milestones will be achieved given the nature of clinical development and the stage of the Company’s technology. The Company has thus determined that all research and development milestones will be constrained until it is deemed probable that a significant revenue reversal will not occur. For revenues from research and development milestones, payments will be recognized consistent with the recognition pattern of the performance obligation to which they relate. For arrangements that include sales-based royalties, including milestone payments based on the level of sales, and for which the license is deemed to be the predominant item to which the royalties relate, the Company recognizes revenue at the later of (i) when the related sales occur, or (ii) when the performance obligation to which some or all of the royalty has been allocated has been satisfied (or partially satisfied). Commercial milestones and sales royalties are determined by sales or usage-based thresholds and will be accounted for under the royalty recognition constraint as constrained variable consideration. Contract Balances The Company recognizes a contract asset when the Company transfers goods or services to a customer before the customer pays consideration or before payment is due, excluding any amounts presented as a receivable (i.e., accounts receivable). A contract asset is an entity’s right to consideration in exchange for goods or services that the entity has transferred to a customer. The contract liabilities (i.e., deferred revenue) primarily relate to contracts where the Company has received payment but has not yet satisfied the related performance obligations. In the event of an early termination of a collaboration agreement, any contract liabilities would be recognized in the period in which all Company obligations under the agreement have been fulfilled. Costs to Obtain and Fulfill a Contract with a Customer Certain costs to obtain customer contracts, including success-based fees paid to third-party service providers, and costs to fulfill customer contracts are capitalized in accordance with FASB ASC 340, Other Assets and Deferred Costs , or ASC 340. These costs are amortized to expense on a systemic basis that is consistent with the transfer to the customer of the goods or services to which the asset relates. The Company will expense the amortization of costs to obtain customer contracts to general and administrative expense and costs to fulfill customer contracts to research and development expense.
Property and Equipment	Property and equipment are recorded at acquisition cost, less accumulated depreciation and impairment. Depreciation on property and equipment is calculated using the straight-line method over the remaining estimated useful lives of the assets. Maintenance and repairs to these assets are charged to expenses as occurred.
Leases	In accordance with ASU No. 2016-2, Leases (Topic 842) , or ASC 842, and for each of the Company’s leases, the following is recognized: (i) a lease liability, which is a lessees obligation to make lease payments arising from a lease, measured on a discounted basis and (ii) a right-of-use asset, which is an asset that represents the lessee’s right to use, or control the use of, a specified asset for the lease term for all leases (with the exception of short-term leases) at the commencement date. The Company determines if an arrangement is a lease at inception. The Company’s contracts are determined to contain a lease within the scope of ASC 842 when all of the following criteria based on the specific circumstances of the arrangement are met: (1) there is an identified asset for which there are no substantive substitution rights; (2) the Company has the right to obtain substantially all of the economic benefits from the identified asset; and (3) the Company has the right to direct the use of the identified asset. At the commencement date, operating lease liabilities and their corresponding right-of-use assets are recorded based on the present value of future lease payments over the expected lease term. The Company’s lease agreements do not provide an implicit rate. As a result, the Company utilizes an estimated incremental borrowing rate to discount lease payments, which is based on the rate of interest the Company would have to pay to borrow a similar amount on a collateralized basis over a similar term and based on observable market data points. Certain adjustments to the right-of-use asset may be required for items such as initial direct costs paid or lease incentives received. Operating lease cost is recognized over the expected term on a straight-line basis. The Company typically only includes an initial lease term in its assessment of a lease agreement. Options to renew a lease are not included in the Company’s assessment unless there is reasonable certainty that the Company will renew. The expected lease term includes noncancelable lease periods and, when applicable, periods covered by an option to extend the lease if the Company is reasonably certain to exercise that option, as well as periods covered by an option to terminate the lease if the Company is reasonably certain not to exercise that option. Assumptions made by the Company at the commencement date are re-evaluated upon occurrence of certain events, including a lease modification. A lease modification results in a separate contract when the modification grants the lessee an additional right of use not included in the original lease and when lease payments increase commensurate with the standalone price for the additional right of use. When a lease modification results in a separate contract, it is accounted for in the same manner as a new lease.
Recent Accounting Pronouncements Adopted and Not Yet Adopted	In December 2019, the FASB issued ASU No. 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes which amends and aims to simplify accounting disclosure requirements regarding a number of topics including intraperiod tax allocation, accounting for deferred taxes when there are changes in consolidation of certain investments, tax basis step up in an acquisition and the application of effective rate changes during interim periods, among other improvements. In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Statements, or ASU 2016-13. ASU 2016-13 significantly changes the impairment model for most financial assets and certain other instruments. The new standard requires that expected credit losses relating to financial assets measured on an amortized cost basis and available-for-sale debt securities be recorded through an allowance for credit losses. It also limits the amount of credit losses to be recognized for available-for-sale debt securities to the amount by which carrying value exceeds fair value, and requires the reversal of previously recognized credit losses if fair value increases. The allowance for credit losses is a valuation account that is deducted from the amortized cost basis of the financial asset(s) to present the net carrying value at the amount expected to be collected on the financial asset. Subsequently, in November 2018, the FASB issued ASU No. 2018-19, Codification Improvements to Topic 326, Financial Instruments-Credit Losses , which clarifies codification and corrects unintended application of the guidance. In November 2019, the FASB issued ASU No. 2019-11, Codification Improvements to Topic 326, Financial Instruments-Credit Losses , which clarifies or addresses specific issues about certain aspects of ASU 2016-13. In November 2019 the FASB also issued ASU No. 2019-10, Financial Instruments-Credit Losses (Topic 326), Derivatives and Hedging (Topic 815), and Leases (Topic 842): Effective Dates , which delays the effective date of ASU 2016-13 by three years for certain smaller reporting companies such as the Company. The guidance in ASU 2016-13 is effective for the Company for financial statements issued for fiscal years beginning after December 15, 2022 and interim periods within those fiscal years, with early adoption permitted. The Company is still evaluating the impact of the adoption of this standard. The Company has considered other recent accounting pronouncements and concluded that they are either not applicable to the business or that the effect is not expected to be material to the unaudited condensed consolidated financial statements as a result of future adoption.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	3 Months Ended
Summary of Significant Accounting Policies (Tables)	Mar. 31, 2021
Accounting Policies [Abstract]
Schedule of Property and Equipment, Useful Lives	The estimated useful life of the different groups of property and equipment is as follows: Asset Classification Estimated useful life (in years) Leasehold improvements shorter of useful life or remaining life of the lease Laboratory furniture and equipment 8 - 14 Office furniture and equipment 5 - 13 Computer and equipment 3 - 7 Property and equipment are summarized as follows (in thousands): March 31, December 31, 2021 2020 Laboratory furniture and equipment $ 10,729 $ 11,188 Office furniture and equipment 2,030 2,120 Computer equipment 384 394 Leasehold improvements 13,542 14,159 Property and equipment, cost 26,685 27,861 Accumulated depreciation (6,173) (5,815) Property and equipment, net $ 20,512 $ 22,046

Revenue (Tables)

Revenue (Tables)	3 Months Ended
Revenue (Tables)	Mar. 31, 2021
Revenue from Contract with Customer [Abstract]
Schedule of Recognized Revenues	The Company recognized revenue from the following strategic partnerships and other license agreements (in thousands): Three Months Ended March 31, 2021 2020 Seagen $ 366 $ 448 AstraZeneca 14,500 2,711 Servier 767 10,102 Total Revenue $ 15,633 $ 13,261
Schedule of Potential Milestone Payments	Under the Company’s existing strategic partnerships and other license agreements, the Company could receive the following potential milestone payments (in millions): Research, Development, Regulatory & Commercial Milestones Sales Milestones AstraZeneca $ 1,096 $ 4,275 Servier 236 211 Seagen 754 450 Total potential milestone payments $ 2,086 $ 4,936

Property and equipment, net (Ta

Property and equipment, net (Tables)	3 Months Ended
Property and equipment, net (Tables)	Mar. 31, 2021
Property, Plant and Equipment [Abstract]
Schedule of property and equipment	The estimated useful life of the different groups of property and equipment is as follows: Asset Classification Estimated useful life (in years) Leasehold improvements shorter of useful life or remaining life of the lease Laboratory furniture and equipment 8 - 14 Office furniture and equipment 5 - 13 Computer and equipment 3 - 7 Property and equipment are summarized as follows (in thousands): March 31, December 31, 2021 2020 Laboratory furniture and equipment $ 10,729 $ 11,188 Office furniture and equipment 2,030 2,120 Computer equipment 384 394 Leasehold improvements 13,542 14,159 Property and equipment, cost 26,685 27,861 Accumulated depreciation (6,173) (5,815) Property and equipment, net $ 20,512 $ 22,046

Accrued Expenses (Tables)

Accrued Expenses (Tables)	3 Months Ended
Accrued Expenses (Tables)	Mar. 31, 2021
Payables and Accruals [Abstract]
Schedule of Accrued Expenses and Other Current Liabilities	Accrued expenses and other current liabilities consisted of the following (in thousands): March 31, December 31, 2021 2020 Accrued accounts payable $ 3,466 $ 1,220 Research and development fees 2,066 2,001 Compensation expense 1,479 2,759 Lease liabilities 987 1,030 Accrued license obligations 799 358 Audit and tax fees 429 128 Other current liabilities 336 235 Total $ 9,562 $ 7,731

Leases (Tables)

Leases (Tables)	3 Months Ended
Leases (Tables)	Mar. 31, 2021
Leases [Abstract]
Operating Lease Costs, Lease Term and Discount Rate	The following table summarizes operating lease costs included in operating expenses (in thousands): Three Months Ended March 31, 2021 2020 Operating lease costs $ 377 $ 404 Variable lease costs (1) 182 188 Total lease cost $ 559 $ 592 (1) Variable lease costs include certain additional charges for operating costs, including insurance, maintenance, taxes, utilities, and other costs incurred, which are billed based on both usage and as a percentage of the Company’s share of total square footage. The following table summarizes the weighted-average remaining lease term and discount rate: As of March 31, 2021 Weighted-average remaining lease term (years) 11.2 Weighted-average discount rate 10.5 %
Maturities of Operating Lease Liabilities	As of March 31, 2021, the maturities of the Company’s operating lease liabilities and future minimum lease payments were as follows (in thousands): Total 2021 $ 1,910 2022 2,349 2023 2,314 2024 2,314 2025 2,314 Thereafter 15,236 Total undiscounted lease payments 26,437 Less: present value adjustment (26,437) Present value of lease liabilities $ —

Corporate Information - Narrati

Corporate Information - Narrative (Details) - USD ($) $ in Thousands	Apr. 24, 2021	Apr. 01, 2021	Mar. 31, 2021	Aug. 31, 2019	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020	May 31, 2013
Business Acquisition [Line Items]
Cash, cash equivalents and investments			$ 66,800		$ 66,800
Total revenue					15,633	$ 13,261
Issuance of common stock, net of issuance costs				$ 50,000	9,673	0
Net loss					(4,172)	(3,597)
Accumulated deficit			(215,578)		(215,578)		$ (211,406)
AstraZeneca
Business Acquisition [Line Items]
Total revenue			$ 13,000		$ 14,500	$ 2,711
AstraZeneca \| Subsequent Event
Business Acquisition [Line Items]
Total revenue		$ 13,000
AstraZeneca \| Private placement \| Subsequent Event
Business Acquisition [Line Items]
Issuance of common stock, net of issuance costs		$ 10,000
Boston Pharmaceuticals \| Subsequent Event \| Exclusive Product License Agreement
Business Acquisition [Line Items]
Collaborative arrangement, upfront payment	$ 10,000
Pieris Pharmaceuticals GmbH
Business Acquisition [Line Items]
Ownership interest acquired (as a percent)								100.00%

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Schedule of Property, Plant and Equipment, Useful Lives (Details)	3 Months Ended
	Mar. 31, 2021
Laboratory furniture and equipment \| Minimum
Property, Plant and Equipment [Line Items]
Property and equipment, useful life	8 years
Laboratory furniture and equipment \| Maximum
Property, Plant and Equipment [Line Items]
Property and equipment, useful life	14 years
Office furniture and equipment \| Minimum
Property, Plant and Equipment [Line Items]
Property and equipment, useful life	5 years
Office furniture and equipment \| Maximum
Property, Plant and Equipment [Line Items]
Property and equipment, useful life	13 years
Computer equipment \| Minimum
Property, Plant and Equipment [Line Items]
Property and equipment, useful life	3 years
Computer equipment \| Maximum
Property, Plant and Equipment [Line Items]
Property and equipment, useful life	7 years

Revenue - Revenue From Licensin

Revenue - Revenue From Licensing Agreements and Strategic Partnerships (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2021	Mar. 31, 2020
Disaggregation of Revenue [Line Items]
Total revenue		$ 15,633	$ 13,261
Seagen
Disaggregation of Revenue [Line Items]
Total revenue		366	448
AstraZeneca
Disaggregation of Revenue [Line Items]
Total revenue	$ 13,000	14,500	2,711
Servier
Disaggregation of Revenue [Line Items]
Total revenue		$ 767	$ 10,102

Revenue - Potential Milestone P

Revenue - Potential Milestone Payments (Details) - Strategic Partnerships and Other License Agreements $ in Millions	Mar. 31, 2021USD ($)
Research, Development, Regulatory & Commercial Milestones
Revenue Recognition, Milestone Method [Line Items]
Total potential milestone payments	$ 2,086
Research, Development, Regulatory & Commercial Milestones \| AstraZeneca
Revenue Recognition, Milestone Method [Line Items]
Total potential milestone payments	1,096
Research, Development, Regulatory & Commercial Milestones \| Servier
Revenue Recognition, Milestone Method [Line Items]
Total potential milestone payments	236
Research, Development, Regulatory & Commercial Milestones \| Seagen
Revenue Recognition, Milestone Method [Line Items]
Total potential milestone payments	754
Sales Milestones
Revenue Recognition, Milestone Method [Line Items]
Total potential milestone payments	4,936
Sales Milestones \| AstraZeneca
Revenue Recognition, Milestone Method [Line Items]
Total potential milestone payments	4,275
Sales Milestones \| Servier
Revenue Recognition, Milestone Method [Line Items]
Total potential milestone payments	211
Sales Milestones \| Seagen
Revenue Recognition, Milestone Method [Line Items]
Total potential milestone payments	$ 450

Revenue - Narrative (Details)

Revenue - Narrative (Details) $ / shares in Units, $ in Thousands, € in Millions

Apr. 24, 2021USD ($)

Apr. 01, 2021USD ($)$ / sharesshares

Mar. 24, 2021USD ($)$ / sharesshares

Feb. 08, 2018USD ($)performanceObligationprogramswapOptionresearchProgramlicense

May 02, 2017performanceObligation

May 02, 2017USD ($)performanceObligation

May 02, 2017researchProgramperformanceObligation

May 02, 2017licenseperformanceObligation

May 02, 2017performanceObligation

May 02, 2017proteinperformanceObligation

May 02, 2017leaseAgreementperformanceObligation

Jan. 04, 2017USD ($)preclinicalMilestonecollaborationProductbispecificTherapeuticProgramperformanceObligationextensionOptionproductlicense

Jan. 04, 2017EUR (€)preclinicalMilestonecollaborationProductbispecificTherapeuticProgramperformanceObligationextensionOptionproductlicense

Mar. 31, 2021USD ($)

Feb. 28, 2021

Feb. 29, 2020collaborationProductprogram

Feb. 28, 2019USD ($)

Feb. 28, 2019EUR (€)

Dec. 31, 2018USD ($)preclinicalMilestone

Dec. 31, 2018EUR (€)preclinicalMilestone

Mar. 31, 2021USD ($)

Sep. 30, 2020USD ($)

Jun. 30, 2020USD ($)

Mar. 31, 2020USD ($)

Dec. 31, 2020USD ($)

Jan. 01, 2019USD ($)

May 02, 2017collaborationProduct

Disaggregation of Revenue [Line Items]

Revenue recognized from contract with customer

$ 800

Deferred revenues, current portion

$ 17,236

17,236

$ 12,627

Deferred revenue, net of current portion

32,315

$ 35,900

Number of technology licenses (in licenses) | leaseAgreement

Total revenue

15,633

$ 13,261

Number of separate performance obligations (in performance obligations) | performanceObligation

Additions to deferred revenue

4,000

Seagen

Disaggregation of Revenue [Line Items]

Number of performance obligations (in performance obligations) | performanceObligation

Remaining performance obligation

22,800

Resale of stock period

60 days

Deferred revenues, current portion

10,200

Deferred revenue, net of current portion

9,400

Total revenue

366

448

Seagen | Private placement

Disaggregation of Revenue [Line Items]

Deferred revenue

$ 3,300

Shares of stock sold (in shares) | shares

3,706,174

Shares of stock sold, net consideration

$ 13,000

Shares of stock sold, price per share (in dollars per share) | $ / shares

$ 3.51

Fair value of stock (in dollars per share) | $ / shares

$ 2.61

AstraZeneca

Disaggregation of Revenue [Line Items]

Deferred revenue

700

Remaining performance obligation

23,800

Revenue recognized from contract with customer

100

Deferred revenues, current portion

900

Deferred revenue, net of current portion

18,100

Research collaboration agreement term

5 years

Total revenue

13,000

14,500

2,711

AstraZeneca | Subsequent Event

Disaggregation of Revenue [Line Items]

Resale of stock period

60 days

Total revenue

$ 13,000

AstraZeneca | Private placement | Subsequent Event

Disaggregation of Revenue [Line Items]

Shares of stock sold (in shares) | shares

3,584,230

Shares of stock sold, net consideration

$ 10,000

Shares of stock sold, price per share (in dollars per share) | $ / shares

$ 2.79

Fair value of stock (in dollars per share) | $ / shares

$ 2.60

Les Laboratoires Servier and Institut de Recherches Internationales Servier

Disaggregation of Revenue [Line Items]

Number of performance obligations (in performance obligations) | performanceObligation

Remaining performance obligation

10,900

Revenue recognized from contract with customer

$ 7,100

Deferred revenues, current portion

6,100

Deferred revenue, net of current portion

4,800

Number of novel proteins (in proteins) | bispecificTherapeuticProgram

Number of research programs (in research programs) | bispecificTherapeuticProgram

Number of programs (in programs) | bispecificTherapeuticProgram

Total revenue

767

10,102

Capitalized contract cost, net

100

Number of separate performance obligations (in performance obligations) | performanceObligation

Number of combined performance obligations (in performance obligations) | performanceObligation

Research term, extension period

12 months

Number of preclinical stage programs (in programs) | program

Preclinical stage performance obligation period

60 days

Amortization of capitalized contract costs

$ 100

Les Laboratoires Servier and Institut de Recherches Internationales Servier | Research and Development Services

Disaggregation of Revenue [Line Items]

Research collaboration agreement term

3 years

Number of preclinical milestones (in preclinical milestones) | preclinicalMilestone

License and Collaboration Agreement | Seagen

Disaggregation of Revenue [Line Items]

Number of research programs (in research programs) | researchProgram

Period after effective date agreements may be terminated

12 months

Contract termination advance notice period

90 days

Agreement termination advance notice period if marketing approval obtained

180 days

Agreement termination notice period upon material breach by the Company

90 days

Contract termination due to material breach, additional notice period if the breach is not susceptible

90 days

Number of licenses (in licenses) | license

Number of swap options (in swap options) | swapOption

Number of performance obligations (in performance obligations) | performanceObligation

License and Collaboration Agreement | AstraZeneca

Disaggregation of Revenue [Line Items]

Period after effective date agreements may be terminated

12 months

Contract termination advance notice period

90 days

Agreement termination advance notice period if marketing approval obtained

180 days

Agreement termination notice period upon material breach by the Company

180 days

Contract termination due to material breach, additional notice period if the breach is not susceptible

180 days

Number of performance obligations (in performance obligations) | performanceObligation

Number of novel proteins (in proteins) | protein

Agreement termination notice period upon breach of payment obligations by the Company

30 days

Period of license performance obligation

12 months

License and Collaboration Agreement | Les Laboratoires Servier and Institut de Recherches Internationales Servier

Disaggregation of Revenue [Line Items]

Number of licenses (in licenses) | license

Number of performance obligations (in performance obligations) | performanceObligation

Number of collaboration products (in collaboration products) | collaborationProduct

Number of research programs (in research programs) | bispecificTherapeuticProgram

Strategic Partnerships and Other License Agreements | Les Laboratoires Servier and Institut de Recherches Internationales Servier

Disaggregation of Revenue [Line Items]

Period after effective date agreements may be terminated

12 months

Contract termination advance notice period

180 days

Revenue recognized from contract with customer

$ 1,700

€ 1.5

$ 600

€ 0.5

Number of collaboration products (in collaboration products) | product

Other arrangement | Seagen

Disaggregation of Revenue [Line Items]

Number of research programs (in research programs) | researchProgram

Platform technology license | Seagen

Disaggregation of Revenue [Line Items]

Number of performance obligations (in performance obligations) | performanceObligation

Number of target programs (in programs) | program

Antibody target swap | Seagen

Disaggregation of Revenue [Line Items]

Number of performance obligations (in performance obligations) | performanceObligation

Governance committee participation | Seagen

Disaggregation of Revenue [Line Items]

Number of performance obligations (in performance obligations) | performanceObligation

Upfront Payment | Seagen

Disaggregation of Revenue [Line Items]

Research and development services

$ 4,900

Deferred revenue

1,200,000

Upfront Payment | Seagen | License fees

Disaggregation of Revenue [Line Items]

Revenue

$ 30,000

Upfront Payment | AstraZeneca

Disaggregation of Revenue [Line Items]

Allocable arrangement consideration

$ 45,000

Upfront Payment | Les Laboratoires Servier and Institut de Recherches Internationales Servier | License fees

Disaggregation of Revenue [Line Items]

Revenue

$ 32,000

€ 30

Additional other research services | AstraZeneca

Disaggregation of Revenue [Line Items]

Allocable arrangement consideration

4,700

Servier Developed Collaboration Product | Les Laboratoires Servier and Institut de Recherches Internationales Servier

Disaggregation of Revenue [Line Items]

Number of collaboration products (in collaboration products) | collaborationProduct

Co-Development Collaboration Product | Les Laboratoires Servier and Institut de Recherches Internationales Servier

Disaggregation of Revenue [Line Items]

Number of collaboration products (in collaboration products) | collaborationProduct

Exclusive Product License Agreement | Boston Pharmaceuticals | Subsequent Event

Disaggregation of Revenue [Line Items]

Period after effective date agreements may be terminated

9 months

Contract termination advance notice period

60 days

Agreement termination advance notice period if marketing approval obtained

120 days

Agreement termination notice period upon material breach by the Company

180 days

Contract termination due to material breach, additional notice period if the breach is not susceptible

180 days

Collaborative arrangement, upfront payment

$ 10,000

Collaborative arrangement, potential additional consideration

$ 352,500

Agreement termination notice period due to non-payment of undisputed amounts

60 days

Estimated Development and Manufacturing Services | Upfront Payment | AstraZeneca

Disaggregation of Revenue [Line Items]

Allocable arrangement consideration

14,200

Milestone Payments | Upfront Payment | Seagen

Disaggregation of Revenue [Line Items]

Revenue recognized from contract with customer

4,200

Allocable arrangement consideration

$ 5,000

Milestone Payments | Upfront Payment | AstraZeneca

Disaggregation of Revenue [Line Items]

Allocable arrangement consideration

12,500

Estimated Phase 2a Services | Upfront Payment | AstraZeneca

Disaggregation of Revenue [Line Items]

Allocable arrangement consideration

$ 4,700

Agreement extension options (in extension options) | Les Laboratoires Servier and Institut de Recherches Internationales Servier | Research and Development Services

Disaggregation of Revenue [Line Items]

Research collaboration agreement term

1 year

Number of agreement extension options (in extension options) | extensionOption

Minimum | License and Collaboration Agreement | AstraZeneca

Disaggregation of Revenue [Line Items]

Number of collaboration products (in collaboration products) | collaborationProduct

Minimum | Strategic Partnerships and Other License Agreements | Les Laboratoires Servier and Institut de Recherches Internationales Servier

Disaggregation of Revenue [Line Items]

Agreement termination notice period upon material breach by the Company

90 days

Maximum | License and Collaboration Agreement | AstraZeneca

Disaggregation of Revenue [Line Items]

Number of collaboration products (in collaboration products)

Number of research programs (in research programs) | researchProgram

Number of research licenses (in licenses)

Maximum | Strategic Partnerships and Other License Agreements | Les Laboratoires Servier and Institut de Recherches Internationales Servier

Disaggregation of Revenue [Line Items]

Agreement termination notice period upon material breach by the Company

120 days

Accounting Standards Update 2014-09 | AstraZeneca

Disaggregation of Revenue [Line Items]

Capitalized contract cost, net

$ 700

$ 1,600

Capitalized contract cost in accordance with ASC 340

1,100

Accounting Standards Update 2014-09 | Les Laboratoires Servier and Institut de Recherches Internationales Servier

Disaggregation of Revenue [Line Items]

Capitalized contract cost, net

$ 500

Cash, cash equivalents and in_2

Cash, cash equivalents and investments - Narrative (Details) - USD ($)	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Cash and Cash Equivalents [Abstract]
Cash equivalents	$ 49,700,000		$ 64,000,000
Realized gains (losses) recognized on available-for-sale investments	$ 0	$ 200,000

Property and equipment, net - S

Property and equipment, net - Summary (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Property, Plant and Equipment [Line Items]
Property and equipment, cost	$ 26,685	$ 27,861
Accumulated depreciation	(6,173)	(5,815)
Property and equipment, net	20,512	22,046
Laboratory furniture and equipment
Property, Plant and Equipment [Line Items]
Property and equipment, cost	10,729	11,188
Office furniture and equipment
Property, Plant and Equipment [Line Items]
Property and equipment, cost	2,030	2,120
Computer equipment
Property, Plant and Equipment [Line Items]
Property and equipment, cost	384	394
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property and equipment, cost	$ 13,542	$ 14,159

Accrued Expenses - Summary (Det

Accrued Expenses - Summary (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Accrued expenses
Accrued accounts payable	$ 3,466	$ 1,220
Research and development fees	2,066	2,001
Compensation expense	1,479	2,759
Lease liabilities	987	1,030
Accrued license obligations	799	358
Audit and tax fees	429	128
Other current liabilities	336	235
Total	$ 9,562	$ 7,731

Net Loss per Share - Narrative

Net Loss per Share - Narrative (Details) - shares shares in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Earnings Per Share [Abstract]
Weighted average shares excluded from the calculation of diluted weighted average shares outstanding (shares)	38.6	34.9

Stockholders' Equity - Narrativ

Stockholders' Equity - Narrative (Details) - USD ($) $ / shares in Units, $ in Thousands	Jun. 23, 2020	Apr. 01, 2020	Mar. 31, 2020	Aug. 31, 2019	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2021	Dec. 31, 2020
Class of Stock [Line Items]
Common stock, shares authorized (in shares)					300,000,000		300,000,000	300,000,000
Common stock, shares issued (in shares)					59,718,989		59,718,989	56,002,815
Common stock, shares outstanding (in shares)					59,718,989		59,718,989	56,002,815
Par value of common stock (USD per share)					$ 0.001		$ 0.001	$ 0.001
Preferred stock, shares authorized (in shares)					10,000,000		10,000,000	10,000,000
Preferred stock, shares issued (in shares)					14,429		14,429	14,429
Preferred stock, shares outstanding (in shares)					14,429		14,429	14,429
Par value of preferred stock (USD per share)					$ 0.001		$ 0.001	$ 0.001
Issuance of common stock, net of issuance costs				$ 50,000	$ 9,673	$ 0
2020 Plan
Class of Stock [Line Items]
Shares of stock authorized pursuant to the 2020 Plan (shares)	3,500,000
2019 Plan
Class of Stock [Line Items]
Shares of stock terminated under the 2019 Plan (shares)	1,579,678
At the market offering
Class of Stock [Line Items]
Shares of stock sold, net consideration							$ 10,000
Common Stock \| Stock exchange, shares from existing shareholders
Class of Stock [Line Items]
Shares of stock sold (in shares)		3,000,000
Preferred Stock \| Preferred share exchange
Class of Stock [Line Items]
Shares of stock sold (in shares)		3,000
Series A Preferred Stock
Class of Stock [Line Items]
Preferred stock, shares issued (in shares)					2,907		2,907	2,907
Preferred stock, shares outstanding (in shares)					2,907		2,907	2,907
Series B Preferred Stock
Class of Stock [Line Items]
Preferred stock, shares issued (in shares)					5,000		5,000	5,000
Preferred stock, shares outstanding (in shares)					5,000		5,000	5,000
Series C Preferred Stock
Class of Stock [Line Items]
Preferred stock, shares issued (in shares)					3,522		3,522	3,522
Preferred stock, shares outstanding (in shares)					3,522		3,522	3,522
Series D Preferred Stock
Class of Stock [Line Items]
Preferred stock, shares issued (in shares)					3,000		3,000	3,000
Preferred stock, shares outstanding (in shares)					3,000		3,000	3,000
Series D Preferred Stock \| Preferred Stock
Class of Stock [Line Items]
Preferred stock, shares authorized (in shares)		3,000
Par value of preferred stock (USD per share)			$ 0.001			$ 0.001
Stock issued upon conversion (shares)			1,000			1,000
Common stock ownership limit (as a percent)			9.99%			9.99%
Beneficial ownership limitation (as a percent)			19.99%			19.99%
Notice period before increase of Beneficial Ownership Limitation			61 days

Leases - Narrative (Details)

Leases - Narrative (Details) $ in Millions	1 Months Ended			3 Months Ended
Leases - Narrative (Details) $ in Millions	May 31, 2020ft²	Feb. 29, 2020USD ($)ft²	Aug. 31, 2015ft²	Mar. 31, 2021USD ($)ft²extensionOption	Mar. 31, 2020USD ($)ft²floorleaseAgreement	Mar. 31, 2019USD ($)	Dec. 31, 2018USD ($)
Loss Contingencies [Line Items]
Lease liabilities \| $				$ 0.7	$ 0.3
Boston, Massachusetts
Loss Contingencies [Line Items]
Area of leased property (square feet)			3,950
Freising, Germany
Loss Contingencies [Line Items]
Area of leased property (square feet)					19,000
Number of lease agreements (in lease agreements) \| leaseAgreement					4
Hallbergmoos, Germany
Loss Contingencies [Line Items]
Area of leased property (square feet)		105,000
Lease term		12 years 6 months
Number of agreement extension options (in extension options) \| extensionOption				2
Lease renewal term				60 months
Rent expense \| $		$ 0.2
Security deposit \| $							$ 0.8
Tenant improvements \| $						$ 11.5
Leases in same building \| Freising, Germany
Loss Contingencies [Line Items]
Number of lease agreements (in lease agreements) \| leaseAgreement					3
Number of floors (in floors) \| floor					3
Leases expected to be delivered by February 2020 \| Hallbergmoos, Germany
Loss Contingencies [Line Items]
Area of leased property (square feet)		98,400
Leases expected to be delivered by May 2020 \| Hallbergmoos, Germany
Loss Contingencies [Line Items]
Area of leased property (square feet)	5,100
Leases expected to be delivered by October 2024 \| Hallbergmoos, Germany
Loss Contingencies [Line Items]
Area of leased property (square feet)				22,300
Leases with first right of refusal for additional area \| Hallbergmoos, Germany
Loss Contingencies [Line Items]
Area of leased property (square feet)				13,400

Leases - Lease Cost (Details)

Leases - Lease Cost (Details) - USD ($) $ in Thousands	3 Months Ended
Leases - Lease Cost (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Mar. 31, 2020
Leases [Abstract]
Operating lease costs	$ 377	$ 404
Variable lease costs	182	188
Total lease cost	$ 559	$ 592

Leases - Summary of the Lease T

Leases - Summary of the Lease Term and Discount Rate (Details)	Mar. 31, 2021
Leases [Abstract]
Weighted-average remaining lease term (years)	11 years 2 months 12 days
Weighted-average discount rate	10.50%

Leases - Maturities of the Oper

Leases - Maturities of the Operating Lease Liabilities (Details) $ in Thousands	Mar. 31, 2021USD ($)
Leases [Abstract]
2021	$ 1,910
2022	2,349
2023	2,314
2024	2,314
2025	2,314
Thereafter	15,236
Total undiscounted lease payments	26,437
Less: present value adjustment	(26,437)
Present value of lease liabilities	$ 0