Exicure (XCUR) 10-Q 12 Aug 20 2020 Q2 Quarterly report Financial data

Cover Page

Cover Page - shares	6 Months Ended
	Jun. 30, 2020	Aug. 10, 2020
Entity Addresses [Line Items]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Jun. 30, 2020
Document Transition Report	false
Entity File Number	001-39011
Entity Registrant Name	EXICURE, INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	81-5333008
Entity Address, Address Line One	2430 N. Halsted St.
Entity Address, City or Town	Chicago
Entity Address, State or Province	IL
Entity Address, Postal Zip Code	60614
City Area Code	(847)
Local Phone Number	673-1700
Title of 12(b) Security	Common Stock, par value $0.0001 per share
Trading Symbol	XCUR
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	true
Entity Ex Transition Period	true
Entity Shell Company	false
Entity Common Stock, Shares Outstanding (in shares)		87,228,586
Entity Central Index Key	0001698530
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q2
Amendment Flag	false
Former Address
Entity Addresses [Line Items]
Entity Address, Address Line One	8045 Lamon Avenue
Entity Address, Address Line Two	Suite 410
Entity Address, City or Town	Skokie
Entity Address, State or Province	IL
Entity Address, Postal Zip Code	60077

UNAUDITED CONDENSED CONSOLIDATE

UNAUDITED CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Current assets:
Cash and cash equivalents	$ 17,198	$ 48,460
Short-term investments	68,579	62,326
Accounts receivable	21	16
Unbilled revenue receivable	3	19
Prepaid expenses and other assets	3,588	1,955
Total current assets	89,389	112,776
Property and equipment, net	4,464	2,099
Other noncurrent assets	2,266	388
Total assets	96,119	115,263
Current liabilities:
Current portion of long-term debt	0	4,965
Accounts payable	1,540	1,814
Accrued expenses and other current liabilities	1,947	2,435
Current portion of deferred revenue		21,873
Total current liabilities	14,367	31,087
Common stock warrant liability	0	414
Deferred revenue, noncurrent	0	2,956
Other noncurrent liabilities	0	59
Total liabilities	14,367	34,516
Stockholders’ equity:
Common stock, $0.0001 par value per share; 200,000,000 shares authorized, 87,206,346 issued and outstanding, June 30, 2020; 86,069,263 issued and outstanding, December 31, 2019	9	9
Additional paid-in capital	165,863	162,062
Accumulated other comprehensive income (loss)	338	(27)
Accumulated deficit	(84,458)	(81,297)
Total stockholders' equity	81,752	80,747
Total liabilities and stockholders’ equity	$ 96,119	$ 115,263

UNAUDITED CONDENSED CONSOLIDA_2

UNAUDITED CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Jun. 30, 2020	Dec. 31, 2019
Statement of Financial Position [Abstract]
Common stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Common stock, shares authorized (in shares)	200,000,000	200,000,000
Common stock, shares issued (in shares)	87,206,346	86,069,263
Common stock, shares outstanding (in shares)	87,206,346	86,069,263

UNAUDITED CONDENSED CONSOLIDA_3

UNAUDITED CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Revenue:
Collaboration revenue	$ 4,847	$ 434	$ 14,030	$ 459
Total revenue	4,847	434	14,030	459
Operating expenses:
Research and development expense	7,008	3,433	13,083	6,828
General and administrative expense	2,229	1,985	4,803	4,193
Total operating expenses	9,237	5,418	17,886	11,021
Operating loss	(4,390)	(4,984)	(3,856)	(10,562)
Other income (expense), net:
Dividend income	4	82	43	187
Interest income	267	1	627	2
Interest expense	0	(203)	(128)	(386)
Other income (expense), net	(192)	(116)	153	253
Total other income (expense), net	79	(236)	695	56
Net loss	$ (4,311)	$ (5,220)	$ (3,161)	$ (10,506)
Basic and diluted loss per common share (in usd per share)	$ (0.05)	$ (0.12)	$ (0.04)	$ (0.24)
Weighted average basic and diluted common shares outstanding (in shares)	87,174,533	44,368,174	87,126,847	44,363,115

UNAUDITED CONDENSED CONSOLIDA_4

UNAUDITED CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) Statement - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Statement of Comprehensive Income [Abstract]
Net loss	$ (4,311)	$ (5,220)	$ (3,161)	$ (10,506)
Unrealized gains on available for sale securities, net of tax	355	0	365	0
Other comprehensive income	355	0	365	0
Comprehensive loss	$ (3,956)	$ (5,220)	$ (2,796)	$ (10,506)

UNAUDITED CONDENSED CONSOLIDA_5

UNAUDITED CONDENSED CONSOLIDATED STATEMENT OF CHANGES IN STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in- Capital	Accumulated Deficit	Accumulated Other Comprehensive Income (Loss)
Beginning balance (in shares) at Dec. 31, 2018		44,358,000
Beginning balance at Dec. 31, 2018	$ 20,952	$ 4	$ 75,942	$ (54,994)	$ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Equity-based compensation	489		489
Net Income (loss)	(5,286)			(5,286)
Ending balance (in shares) at Mar. 31, 2019		44,358,000
Ending balance at Mar. 31, 2019	16,155	$ 4	76,431	(60,280)	0
Beginning balance (in shares) at Dec. 31, 2018		44,358,000
Beginning balance at Dec. 31, 2018	20,952	$ 4	75,942	(54,994)	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Other comprehensive income, net	0
Net Income (loss)	(10,506)
Ending balance (in shares) at Jun. 30, 2019		44,369,790
Ending balance at Jun. 30, 2019	11,391	$ 4	76,887	(65,500)	0
Beginning balance (in shares) at Mar. 31, 2019		44,358,000
Beginning balance at Mar. 31, 2019	16,155	$ 4	76,431	(60,280)	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of options (in shares)		11,790
Exercise of options	17		17
Equity-based compensation	439		439
Other comprehensive income, net	0
Net Income (loss)	(5,220)			(5,220)
Ending balance (in shares) at Jun. 30, 2019		44,369,790
Ending balance at Jun. 30, 2019	11,391	$ 4	76,887	(65,500)	0
Beginning balance (in shares) at Dec. 31, 2019		86,069,263
Beginning balance at Dec. 31, 2019	80,747	$ 9	162,062	(81,297)	(27)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Equity-based compensation	441		441
Issuance of common stock (in shares)		1,081,184
Issuance of common stock	2,766		2,766
Other comprehensive income, net	10				10
Net Income (loss)	1,150			1,150
Ending balance (in shares) at Mar. 31, 2020		87,150,447
Ending balance at Mar. 31, 2020	85,114	$ 9	165,269	(80,147)	(17)
Beginning balance (in shares) at Dec. 31, 2019		86,069,263
Beginning balance at Dec. 31, 2019	$ 80,747	$ 9	162,062	(81,297)	(27)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of options (in shares)	55,899
Other comprehensive income, net	$ 365
Net Income (loss)	(3,161)
Ending balance (in shares) at Jun. 30, 2020		87,206,346
Ending balance at Jun. 30, 2020	81,752	$ 9	165,863	(84,458)	338
Beginning balance (in shares) at Mar. 31, 2020		87,150,447
Beginning balance at Mar. 31, 2020	85,114	$ 9	165,269	(80,147)	(17)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of options (in shares)		55,899
Exercise of options	50		50
Equity-based compensation	544		544
Other comprehensive income, net	355				355
Net Income (loss)	(4,311)			(4,311)
Ending balance (in shares) at Jun. 30, 2020		87,206,346
Ending balance at Jun. 30, 2020	$ 81,752	$ 9	$ 165,863	$ (84,458)	$ 338

UNAUDITED CONDENSED CONSOLIDA_6

UNAUDITED CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($)	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
Cash flows from operating activities:
Net loss	$ (3,161,000)	$ (10,506,000)
Adjustments to reconcile net loss to cash used in operating activities:
Depreciation and amortization	335,000	174,000
Equity-based compensation	985,000	928,000
Amortization of long-term debt issuance costs and fees	35,000	86,000
Other	356,000	36,000
Change in fair value of warrant liabilities	(157,000)	(256,000)
Changes in operating assets and liabilities:
Unbilled revenue receivable and accounts receivable	11,000	3,000
Prepaid expenses and other current assets	(1,551,000)	(257,000)
Other noncurrent assets	(1,034,000)	112,000
Accounts payable	22,000	403,000
Accrued expenses and other current liabilities	(647,000)	(66,000)
Deferred revenue	(13,949,000)	541,000
Other noncurrent liabilities	(59,000)	(194,000)
Net cash used in operating activities	(18,814,000)	(8,996,000)
Cash flows from investing activities:
Purchase of available for sale securities	(38,072,000)	0
Proceeds from sale or maturity of available for sale securities	32,103,000	0
Capital expenditures	(2,996,000)	(62,000)
Net cash used in investing activities	(8,965,000)	(62,000)
Cash flows from financing activities:
Proceeds from common stock offering	2,973,000	0
Proceeds from exercise of common stock options	50,000	17,000
Repayment of long-term debt	4,999,000	0
Payment of long-term debt fees and issuance costs	(100,000)	(52,000)
Payment of common stock financing costs	(207,000)	0
Net cash used in financing activities	(2,283,000)	(35,000)
Net decrease in cash, cash equivalents, and restricted cash	(30,062,000)	(9,093,000)
Cash, cash equivalents, and restricted cash - beginning of period	48,460,000	26,268,000
Cash, cash equivalents, and restricted cash - end of period	18,398,000	17,175,000
Non-cash financing activities:
Debt fees (accrued expenses)	0	100,000
Non-cash investing activities:
Capital expenditures (accounts payable and accrued expenses)	60,000	14,000
Total cash, cash equivalents, and restricted cash shown in the unaudited condensed consolidated statements of cash flows	$ 18,398,000	$ 17,175,000

Description of Business and Bas

Description of Business and Basis of Presentation	6 Months Ended
	Jun. 30, 2020
Accounting Policies [Abstract]
Description of Business and Basis of Presentation	Description of Business and Basis of Presentation Description of Business Exicure, Inc. (the “Company”) is a clinical-stage biotechnology company developing therapeutics for immuno-oncology, genetic disorders and other indications based on our proprietary Spherical Nucleic Acid (“SNA”) technology. SNAs are nanoscale constructs consisting of densely packed synthetic nucleic acid sequences that are radially arranged in three dimensions. The Company believes that the design of its SNAs gives rise to distinct chemical and biological properties that may provide advantages over other nucleic acid therapeutics and enable therapeutic activity outside of the liver. The Company is working to advance its SNA therapeutic candidates through multiple clinical trials, including the ongoing Phase 1b/2 clinical trial of cavrotolimod (AST-008) in cancer patients. The Company believes that one of the key strengths of its proprietary SNAs is that they have the potential to enter a number of different cells and organs. The Company has shown in clinical and preclinical studies that SNAs may have therapeutic potential in immunoncology and dermatology. In addition, the Company has shown in preclinical studies that SNAs may have therapeutic potential in neurology, ophthalmology, pulmonology, and gastroenterology. As a consequence, the Company has expanded its pipeline into neurology, and has conducted early stage research activities in ophthalmology, pulmonology, and gastroenterology. Throughout these unaudited condensed consolidated financial statements, the terms the “Company” and “Exicure” refer to Exicure, Inc. and its wholly owned subsidiary, Exicure Operating Company. Exicure Operating Company holds all material assets and conducts all business activities and operations of Exicure, Inc. Basis of Presentation The accompanying unaudited condensed consolidated financial statements as of June 30, 2020 and December 31, 2019, and for the three and six months ended June 30, 2020 and 2019, have been presented in conformity with generally accepted accounting principles in the United States (“GAAP”). Principles of Consolidation The accompanying unaudited condensed consolidated financial statements include the accounts of Exicure, Inc. and its wholly owned subsidiary, Exicure Operating Company. All intercompany transactions and accounts are eliminated in consolidation. Significant Risks and Uncertainties In response to the ongoing COVID-19 pandemic, the Company has taken and continues to take active measures designed to address and mitigate the impact of the COVID-19 pandemic on its business, such as remote working policies, facilitating management’s routine communication to address employee and business concerns and providing frequent updates to the Company’s board of directors (the “Board”). As of July 1, 2020, the Company took occupancy of approximately 30,000 square feet of laboratory and office space in its new headquarters in Chicago, Illinois. Since then, the Company has operated under COVID-19 social distancing guidelines and has generally operated with 100% of its R&D staff on-site. The Company’s office and general and administrative team continues to work predominantly from home. The Company’s preclinical development program in Friedreich’s ataxia (“FA”) is ongoing and it continues to expect that IND-enabling studies for the Company’s FA therapeutic candidate, XCUR-FXN, will begin in late 2020. The Company also continues to progress its collaborations with Allergan Pharmaceuticals International Limited (“Allergan”) and DERMELIX, LLC, d/b/a Dermelix Biotherapeutics (“Dermelix”). However, if the COVID-19 pandemic continues to persist for an extended period of time, the Company could experience significant disruptions to its preclinical development timelines, which would adversely affect its business, financial condition, results of operations and growth prospects. The Company anticipates that the COVID-19 pandemic may have an impact on the clinical development timelines for its cavrotolimod (AST-008) clinical program. The extent to which the COVID-19 pandemic will impact the Company’s business, its clinical development and regulatory efforts, its corporate development objectives and the value of and market for its common stock, will depend on future developments that are highly uncertain and cannot be predicted with confidence at this time, such as the ultimate duration or spread of the pandemic, the possibility of additional periods of increases or spikes in the number of COVID-19 cases, travel restrictions, quarantines, social distancing, phased re-openings and business closure requirements in the United States and other countries, and the effectiveness of actions taken globally to contain and treat the disease. The global economic slowdown, the overall disruption of global healthcare systems and the other risks and uncertainties associated with the pandemic could have a material adverse effect on the Company’s business, financial condition, results of operations and growth prospects. In addition, the Company is subject to other challenges and risks specific to its business and its ability to execute on its business plan and strategy, as well as risks and uncertainties common to companies in the biotechnology industry with research and development operations, including, without limitation, risks and uncertainties associated with: obtaining regulatory approval of its product candidates; delays or problems in obtaining clinical supply, loss of single source suppliers or failure to comply with manufacturing regulations; identifying, acquiring or in-licensing additional products or product candidates; product development and the inherent uncertainty of clinical success; and the challenges of protecting and enhancing its intellectual property rights; and the challenges of complying with applicable regulatory requirements. In addition, to the extent the ongoing COVID-19 pandemic adversely affects the Company’s business and results of operations, it may also have the effect of heightening many of the other risks and uncertainties. Liquidity Risk As of June 30, 2020, the Company has generated an accumulated deficit of $103,295 since inception and expects to incur significant expenses and negative cash flows for the foreseeable future. Based on the Company’s current operating plans, it believes that existing working capital at June 30, 2020 is sufficient to fund the Company for at least the next 12 months. Management believes that it will be able to obtain additional working capital through equity financings, partnerships and licensing, or other arrangements, to fund operations. However, there can be no assurance that such additional financing will be available and, if available, can be obtained on terms acceptable to the Company. The Company has historically principally raised capital through the sale of its securities. However, the COVID-19 pandemic continues to rapidly evolve and has already resulted in a significant disruption of global financial markets. The Company believes raising capital in the current market could be very difficult for early stage biotech companies like Exicure. If the disruption continues to persist and deepens, the Company could experience an inability to access additional capital, which could in the future negatively affect its operations. Unaudited Interim Financial Information The accompanying interim condensed consolidated balance sheet as of June 30, 2020, the interim condensed consolidated statements of operations for the three and six months ended June 30, 2020 and 2019, the interim condensed consolidated statements of comprehensive loss for the three and six months ended June 30, 2020 and 2019, the interim condensed consolidated statements of changes in stockholders’ equity for the three and six months ended June 30, 2020 and 2019, and the interim condensed consolidated statements of cash flows for the six months ended June, 2020 and 2019, are unaudited. The interim unaudited condensed consolidated financial statements have been prepared on the same basis as the annual audited financial statements; and in the opinion of management, reflect all adjustments, which include only normal recurring adjustments necessary for the fair statement of the Company’s financial position as of June 30, 2020, the results of its operations for the three and six months ended June 30, 2020 and 2019, and the results of its cash flows for the six months ended June 30, 2020 and 2019. The financial data and other information disclosed in these notes related to the three and six months ended June 30, 2020 and 2019 are unaudited. The results for the three and six months ended June 30, 2020 are not necessarily indicative of results to be expected for the year ending December 31, 2020, or any other interim periods, or any future year or period. Use of Estimates The preparation of the financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Management bases its estimates on certain assumptions which it believes are reasonable in the circumstances and while actual results could differ from those estimates, management does not believe that any change in those assumptions in the near term would have a significant effect on the Company’s financial position, results of operations or cash flows. Actual results in future periods could differ from those estimates.

Significant Accounting Policies

Significant Accounting Policies	6 Months Ended
	Jun. 30, 2020
Accounting Policies [Abstract]
Significant Accounting Policies	Significant Accounting Policies The Company’s significant accounting policies are disclosed in the audited consolidated financial statements and the notes thereto, which are included in the in the Company’s Annual Report on Form 10-K for the year ended December 31, 2019 filed with the U.S. Securities and Exchange Commission (“SEC”) on March 10, 2020. Since the date of those audited consolidated financial statements, there have been no material changes to the Company’s significant accounting policies. Recently Adopted Accounting Pronouncements None. Recent Accounting Pronouncements Not Yet Adopted Financial Instruments - Credit Losses In June 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) ASU 2016-13, Measurement of Credit Losses on Financial Instruments (“ASU 2016-13) . ASU 2016-13 is a new standard intended to improve reporting requirements specific to loans, receivables and other financial instruments. ASU 2016-13 requires that credit losses on financial assets measured at amortized cost be determined using an expected loss model, instead of the current incurred loss model, and requires that credit losses related to available-for-sale debt securities be recorded through an allowance for credit losses and limited to the amount by which carrying value exceeds fair value. ASU 2016-13 also requires enhanced disclosure of credit risk associated with financial assets. The effective date of ASU 2016-13 was deferred by ASU 2019-10, Financial Instruments—Credit Losses (Topic 326), Derivatives and Hedging (Topic 815), and Leases (Topic 842)—Effective Dates to the annual period beginning after December 15, 2022 for companies that (i) meet the definition of an SEC filer and (ii) are eligible as “smaller reporting companies” as such term is defined by the SEC, with early adoption permitted. The Company is currently assessing the impact of adoption of ASU 2016-13 to its consolidated financial statements.

Collaborative Research and Lice

Collaborative Research and License Agreements	6 Months Ended
	Jun. 30, 2020
Research and Development [Abstract]
Collaborative Research and License Agreements	Collaborative Research and License Agreements Allergan Collaboration Agreement Summary of Agreement On November 13, 2019 (the “Effective Date”), the Company entered into a Collaboration, Option and License Agreement (the “Allergan Collaboration Agreement”), with a wholly-owned subsidiary of Allergan plc, Allergan. On May 8, 2020, Allergan plc, including Allergan, was acquired by AbbVie Inc. (“AbbVie”). Accordingly, all references to “Allergan” in the defined terms including, but not limited to, “Allergan,” “Allergan Collaboration Agreement,” “Allergan R&D Services” and “Allergan JDC Services,” should be read and construed as references to AbbVie. Pursuant to the Allergan Collaboration Agreement, the Company granted to Allergan exclusive access and options to license SNA based therapeutics arising from two collaboration programs related to the treatment of hair loss disorders (each, a “Collaboration Program”). Under each such license (obtained in connection with the exercise of an Option, as defined and discussed further below), the Company would grant to Allergan exclusive, royalty-bearing, sublicenseable, nontransferable, worldwide rights to develop, manufacture, use and commercialize such SNA therapeutics. Under the Allergan Collaboration Agreement, the Company will use commercially reasonable efforts to conduct two Collaboration Programs, each focused on one or more hair loss disorders to discover one or more SNA products that are directed to, bind to or inhibit one or more specific Collaboration Program targets (each, a “Program Target”). As of the Effective Date, the Company and Allergan have agreed upon a development plan for each Collaboration Program that describes the development activities and timelines required to advance such Collaboration Program through first IND filing (each, a “Development Plan”). The activities described in the Development Plan are conducted under the supervision of the Joint Development Committee (the “JDC”) consisting of three members from each of the Company and Allergan. The Company is primarily responsible for performing early stage discovery and preclinical activities (the “Initial Development Activities”) set forth in the Development Plan for each Collaboration Program and will be solely responsible for all costs and expenses related to the Initial Development Activities. Allergan may elect, in its sole discretion and at its sole cost and expense, to conduct formulation assessment and in vivo testing as set forth in a Development Plan. Following the completion of all Initial Development Activities, the Company is required to deliver to Allergan a report that describes the results of the Initial Development Activities and identifies at least one SNA-based compound that satisfies certain criteria for such Collaboration Program as determined by the JDC (the “Initial Development Report”). Following the delivery of the Initial Development Report for a Collaboration Program, Allergan will have the ability for a defined period of time (the “Initial Option Exercise Period”) to exercise an option (each an “Option”) to obtain worldwide rights and license to the Company’s SNA technology and the Company’s interest in joint collaboration technology to make, have made, import, use, sell or offer for sale any product (each a “Licensed Product”) that results from such Collaboration Program during the term of the Allergan Collaboration Agreement. At Allergan’s sole option, Allergan may extend the Initial Option Exercise Period (the “Option Extension”) and require the Company to perform IND-enabling activities described in the Development Plan (the “IND-Enabling Activities”), subject to the payment of additional consideration (“Extension Exercise”). If Allergan exercises the Option Extension, the Company would be responsible for conducting the IND-Enabling Activities and would be solely responsible for all costs and expenses associated with such activities. Upon completion of the IND-Enabling Activities, the Company is required to deliver a report that describes the results of the IND-Enabling Activities (the “IND-Enabling Activities Data Package”) to Allergan. Following the delivery of IND-Enabling Activities Data Package, Allergan will have the ability for a defined period of time (the “Extended Option Exercise Period”) to exercise an Option with respect to such Collaboration Program. After the exercise of an Option with respect to a Collaboration Program, Allergan will be responsible for all development, manufacturing, and commercialization activities, and costs and expense associated with such activities in connection with Licensed Products arising from such Collaboration Program. The Company’s obligation to conduct the activities defined in the Development Plan under the Allergan Collaboration Agreement commenced on November 13, 2019 and continues until the earlier of (i) the date Allergan exercises an Option, (ii) the date Allergan abandons a Collaboration Program and foregoes its Option to that Collaboration Program, or (iii) the fifth anniversary of the Effective Date (the “Research Term”). If the Initial Option Exercise Period or Extended Option Exercise Period is still in effect for a Collaboration Program or if the Company has not delivered a complete Initial Development Report or, if Allergan made an Extension Exercise for a Collaboration Program, a complete IND-Enabling Activities Data Package for such Collaboration Program, as determined by the JDC, then the Research Term will automatically extend by one-year increments until such obligation is satisfied, but in no event past the seventh anniversary of the Effective Date. Under the terms of the Allergan Collaboration Agreement, the Company received a $25,000 upfront, non-refundable, non-creditable cash payment (the “Allergan Upfront Payment”) related to the Company’s research and development costs for conducting the Development Plan for two Collaboration Programs, each focused on one or more targets, and certain options to obtain exclusive, worldwide licenses under certain intellectual property rights owned or controlled by the Company to develop, manufacture and commercialize certain products resulting from each such Collaboration Programs. The option exercise fee during the Initial Option Exercise Period is $10,000 per Collaboration Program. If Allergan elects to extend the Initial Option Exercise Period, Allergan is required to pay an additional fee of $10,000. If Allergan elects to exercise its option during the Extended Option Exercise Period, Allergan must pay the Company the option exercise fee of $15,000. Following the exercise by Allergan of an Option with respect to a Collaboration Program, Allergan would be required to make certain milestone payments to the Company upon the achievement of specified development, product approval and launch, and commercial events, on a Licensed Product by Licensed Product basis. On a Licensed Product by Licensed Product basis, for the first Licensed Product to achieve the associated milestone event, the Company is eligible to receive up to an aggregate of $55,000 for development milestone payments and $132,500 for product approval and launch milestone payments. The Company is also eligible for up to $175,000 in sales milestone payments on a Collaboration Program by Collaboration Program basis, associated with aggregate worldwide sales. Certain product approval milestones are subject to certain reductions under specified circumstances, including for payments required to be made by Allergan to obtain certain third party intellectual property rights. In addition, to the extent there is any Licensed Product, the Company would be entitled to receive tiered royalty payments of mid-single digits to the mid-teens percentage on future net worldwide product sales of such Licensed Products, subject to certain reductions under specified circumstances. Royalties are due on a Licensed Product by Licensed Product and country by country basis from the date of the first commercial sale of each Licensed Product in a country until the latest to occur of: (i) the expiration date in such country of the last to expire valid claim within the licensed intellectual property covering the manufacture, use or sale of such Licensed Product in such country, (ii) the tenth anniversary of the first commercial sale of such Licensed Product in such country, and (iii) the expiration of regulatory exclusivity for such Licensed Product in such country. Allergan may terminate the Allergan Collaboration Agreement for any reason or no reason, either in its entirety or on a Collaboration Program by Collaboration Program basis, at any time on 90 days’ prior written notice to the Company. Unless earlier terminated, the term of the Allergan Collaboration Agreement shall continue until (i) if both Option Exercise Periods expire without Allergan exercising either Option, the expiration of the later to expire Option Exercise Period, and (ii) if either or both Options are exercised on a Licensed Product-by-Licensed Product and country-by-country basis, the expiration of the royalty term for such Licensed Product in such country. Either party may terminate the Allergan Collaboration Agreement if the other party has materially breached or defaulted in the performance of any of its material obligations and such breach or default continues after the specified cure period. Termination of the Allergan Collaboration Agreement for any reason will not release either party from any liability which, at the time of such termination, has already accrued to the other party or which is attributable to a period prior to such termination. In addition, termination of the Allergan Collaboration Agreement will not preclude either party from pursuing any rights and remedies it may have under the agreement or at law or in equity with respect to any breach of the Allergan Collaboration Agreement. If either party terminates the Allergan Collaboration Agreement, the license and rights granted to Allergan with respect to the terminated Collaboration Program or License Product shall terminate. Accounting Analysis The Company concluded that Allergan is a customer in this arrangement, and as such the arrangement falls within the scope of the revenue recognition guidance. Under the Allergan Collaboration Agreement, the Company has identified a single performance obligation that includes (i) the research and development activities during the Research Term (the “Allergan R&D Services”), and (ii) Joint Development Committee services during the Research Term (the “Allergan JDC Services”). The Company has concluded that the Allergan R&D Services is not distinct from the Allergan JDC Services during the Research Term. The JDC provides oversight and management of the overall Allergan Collaboration Agreement, and the members of the JDC from the Company have specialized industry knowledge, particularly as it relates to SNA technology. The JDC is meant to facilitate the early stage research being performed and coordinate the activities of both the Company and Allergan. Further, the JDC services are critical to the ongoing evaluation of a Collaboration Program and the drafting and evaluation of the Initial Development Report and the IND-Enabling Data Package. Accordingly, the Company’s participation on the JDC is essential to Allergan receiving value from the Allergan R&D Services and as such, the Allergan JDC Services along with the Allergan R&D Services are considered one performance obligation (the “Collaboration Program Services”). In addition, the Company has concluded that the option to purchase two development and commercialization licenses is considered a marketing offer as the options did not provide any discounts or other rights that would be considered a material right in the arrangement, and thus, not a performance obligation at the onset of the agreement. The consideration for these options will be accounted for when they are exercised. As of the Effective Date of the Allergan Collaboration Agreement, the total transaction price was determined to be $25,000, consisting solely of the Allergan Upfront Payment. The Company also utilized the most likely amount method to estimate any development and regulatory milestone payments to be received. As of the Effective Date of the Allergan Collaboration Agreement, there were no milestones included in the transaction price. The milestones were fully constrained due to the significant uncertainties surrounding such payments. The Company considered the stage of development and the risks associated with the remaining development required to achieve the milestone, as well as whether the achievement of the milestone is outside the control of the Company or Allergan. The Company has determined that any commercial milestones and sales-based royalties will be recognized when the related sales occur and therefore have also been excluded from the transaction price. The Company will re-evaluate the transaction price at the end of each reporting period and as uncertain events are resolved or other changes in circumstances occur. As of June 30, 2020, the Company determined that any development, regulatory, or commercial milestones continue to be constrained and therefore the related milestone payments continue to be excluded from the transaction price at June 30, 2020. The Company will recognize revenue related to the Collaboration Program Services as the performance obligation is satisfied using an input method to measure progress. The Company believes the input method that most accurately depicts the measure of progress is the actual hours incurred to date relative to projected hours to complete the research service. During the three and six months ended June 30, 2020, the Company recognized revenue under the Allergan Collaboration Agreement of approximately $4,833 and $13,949, respectively. As of June 30, 2020, there was $10,880 of deferred revenue related to the Allergan Collaboration Agreement, which is classified as current on the unaudited condensed consolidated balance sheet. Dermelix Collaboration Agreement Summary of Agreement On February 17, 2019, Exicure entered into a License and Development Agreement with Dermelix (the “Dermelix Collaboration Agreement.”) Pursuant to the Dermelix Collaboration Agreement, the Company granted to Dermelix exclusive, worldwide royalty-bearing license rights to, develop, manufacture, have manufactured, use and commercialize the Company’s SNA technology for the treatment of Netherton Syndrome (“NS”) and, at Dermelix’s option, up to five additional specified orphan diseases that are within the dermatology field. Upon written notice to the Company, Dermelix may exercise its option at any time following the effective date of the Dermelix Collaboration Agreement until the date that is six Dermelix will initially seek to develop a targeted therapy for the treatment of NS. Under the terms of the Dermelix Collaboration Agreement, the Company will be responsible for conducting the early stage development for each indication up to IND enabling toxicology studies. Dermelix will assume subsequent development, commercial activities and financial responsibility for such indications. Dermelix will pay the costs and expenses of development and commercialization of any licensed products under the Dermelix Collaboration Agreement, including the Company’s expenses incurred in connection with development activities and in accordance with the development budget. Under the terms of the Dermelix Collaboration Agreement, Exicure received an upfront payment of $1,000, to be applied against the initial $1,000 of the Company’s development expenses. If Dermelix exercises any of its option rights for additional indications, Dermelix will pay an option exercise fee equal to $1,000 for each exercised option (each, an “Option Exercise Fee”). Any Option Exercise Fee will be applied against the Company’s development expenses with respect to the particular indication for which the option was exercised. Pursuant to the Dermelix Collaboration Agreement, the Company shall have the right to pursue the development and commercialization of SNA technology for the treatment of orphan diseases which are neither NS nor one of the additional specified orphan diseases selected by Dermelix pursuant to its option rights. If the Company commences development activities of SNA technology for the treatment of such an orphan disease, the Company will notify Dermelix in writing of such development and Dermelix will have thirty For each of NS as well as any additional licensed product for which Dermelix exercises one of its options, the Company shall be eligible to receive additional cash payments totaling up to $13,500 upon achievement of certain development and regulatory milestones and up to $152,500 upon achievement of certain sales milestones. The regulatory milestones are payable upon the initiation or completion of clinical trials, and regulatory approval in the United States and outside the United States, per program. The commercial sales milestones are payable upon achievement of specified aggregate annual product sales thresholds. In the event a therapeutic candidate subject to the collaboration results in commercial sales, the Company will receive low double-digit royalties on annual net sales for such licensed products. Accounting Analysis The Company concluded that Dermelix is a customer in this arrangement, and as such the arrangement falls within the scope of the revenue recognition guidance. The Company identified performance obligations under the Dermelix Collaboration Agreement for the license of intellectual property for the NS therapeutic candidate and associated research and development services for the NS therapeutic candidate. The Company determined that the performance obligations were not separately identifiable and were not distinct or distinct within the context of the contract due to the specialized nature of the services to be provided by Exicure, specifically with respect to the Company’s expertise related to SNA technology, and the interdependent relationship between the performance obligations. As such, the Company concluded that there is a single identified performance obligation. The Company used the most likely amount method to estimate variable consideration and estimated that the most likely amount for each potential development and regulatory milestone, which is considered variable consideration, was zero, as the achievement of those milestones is uncertain and highly susceptible to factors outside of the Company’s control. Accordingly, all such milestones were excluded from the transaction price. Management will re-evaluate the transaction price at the end of each reporting period and as uncertain events are resolved or other changes in circumstances occur and adjust the transaction price as necessary. Sales-based royalties, including commercial sales milestone payments based on the level of sales, were also excluded from the transaction price, as the license is deemed to be the predominant item to which the royalties relate. The Company will recognize such 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). Revenue associated with the performance obligation will be recognized as services are provided using a cost-to-cost measure of progress method. The transfer of control occurs over time and, in management’s judgment, this input method is the best measure of progress towards satisfying the performance obligation under the Dermelix Collaboration Agreement and reflects a faithful depiction of the transfer of goods and services. The Company initially recorded the upfront payment of $1,000 as deferred revenue related to its wholly unsatisfied performance obligation and reduced this balance to zero during 2019 by recognizing revenue as services were provided. The Company recognized $14 and $81 of revenue under the Dermelix Collaboration Agreement during the three and six months ended June 30, 2020, respectively, which reflects reimbursement by Dermelix for additional costs incurred by Exicure for early stage development costs beyond the initial $1,000 upfront payment. The Company expects to incur additional early stage development costs and expects to be reimbursed by Dermelix for such costs under the terms of the Dermelix Collaboration Agreement. The Company will recognize both revenue and research and development expense for such costs on a gross basis during the period in which those costs are incurred. The Company recognized $434 and $459 of revenue under the Dermelix Collaboration Agreement during the three and six months ended June 30, 2019, respectively, which related to amortization of the above-mentioned deferred revenue related to the upfront payment for services provided during that period.

Supplemental Balance Sheet Info

Supplemental Balance Sheet Information	6 Months Ended
	Jun. 30, 2020
Supplemental Balance Sheet Information [Abstract]
Supplemental Balance Sheet Information	Supplemental Balance Sheet Information Prepaid expenses and other current assets June 30, December 31, Prepaid clinical, contract research and manufacturing costs $ 2,203 $ 481 Interest receivable 221 236 Prepaid insurance 212 533 Other 952 705 Prepaid expenses and other current assets $ 3,588 $ 1,955 Property and equipment, net June 30, December 31, Scientific equipment $ 3,315 $ 2,795 Leasehold improvements 192 192 Computers and software 48 32 Furniture and fixtures 41 41 Construction in process 2,512 356 Property and equipment, gross 6,108 3,416 Less: accumulated depreciation (1,644) (1,317) Property and equipment, net $ 4,464 $ 2,099 Depreciation and amortization expense was $187 and $87 for the three months ended June 30, 2020 and 2019, respectively, and $335 and $174 for the six months ended June 30, 2020 and 2019, respectively. Other noncurrent assets June 30, December 31, Restricted cash $ 1,200 $ — Prepaid lease costs 823 — Prepaid services 233 — Operating lease asset — 356 Other 10 32 Total other noncurrent assets $ 2,266 $ 388 Accrued expenses and other current liabilities June 30, December 31, Accrued payroll-related expenses $ 706 $ 920 Accrued legal expenses 362 254 Accrued clinical, contract research and manufacturing costs 303 515 Common stock warrant liability 257 — Operating lease liability 196 292 Accrued other expenses 123 454 Accrued expenses and other current liabilities $ 1,947 $ 2,435 Other noncurrent liabilities June 30, December 31, Operating lease liability $ — $ 59 Total other noncurrent liabilities $ — $ 59

Investments

Investments	6 Months Ended
	Jun. 30, 2020
Investments [Abstract]
Investments	Investments As of June 30, 2020 and December 31, 2019, the Company primarily invested its excess cash in debt instruments of corporations, the U.S. Treasury, financial institutions, and U.S. government agencies with strong credit ratings and an investment grade rating at or above a long-term rating of Aa3/AA- and a short-term rating of P1/A1. The Company has established guidelines relative to diversification and maturities that maintain safety and liquidity. The Company periodically reviews and modifies these guidelines to maximize trends in yields and interest rates without compromising safety and liquidity. The following table summarizes the contract maturity of the available-for-sale securities the Company held as of June 30, 2020: One year or less 92 % After one year but within two years 8 % Total 100 % All of the Company’s available-for-sale securities are available to the Company for use in its current operations. As a result, the Company categorizes all of these securities as current assets even though the stated maturity of some individual securities may be one year or more beyond the balance sheet date. The amortized cost, gross unrealized holding gains, gross unrealized holding losses and fair value of cash equivalents and available-for-sale securities by type of security at June 30, 2020 and December 31, 2019 were as follows: June 30, 2020 Amortized Costs Gross Unrealized Holding Gains Gross Unrealized Holding Losses Fair Value Commercial paper $ 15,166 $ 22 $ — $ 15,188 Corporate notes/bonds 44,798 271 (4) 45,065 U.S. Treasuries 2,257 18 — 2,275 U.S. Government agency securities 6,020 31 — 6,051 $ 68,241 $ 342 $ (4) $ 68,579 December 31, 2019 Amortized Costs Gross Unrealized Holding Gains Gross Unrealized Holding Losses Fair Value Commercial paper $ 13,932 $ 1 $ (2) $ 13,931 Corporate notes/bonds 36,620 1 (24) 36,597 U.S. Treasuries 4,513 — (1) 4,512 U.S. Government agency securities 9,786 — (2) 9,784 $ 64,851 $ 2 $ (29) $ 64,824

Debt

Debt	6 Months Ended
	Jun. 30, 2020
Debt Disclosure [Abstract]
Debt	DebtOn March 2, 2020, pursuant to the terms of the loan agreement with Hercules Technology Growth Capital (“Hercules”) and subsequent amendments thereto (the “Hercules Loan Agreement”), the Company repaid all remaining outstanding obligations under the Hercules Loan Agreement as of the maturity date, including the outstanding principal balance of $4,999 and the end of term fee of $100.The Company paid interest on the Hercules Loan Agreement of $0 and $152 during the three months ended June 30, 2020 and 2019, respectively, and $142 and $301 during the six months ended June 30, 2020 and 2019, respectively.

Leases

Leases	6 Months Ended
	Jun. 30, 2020
Leases [Abstract]
Leases	Leases Chicago Lease The Company has approximately thirty thousand square feet of office and laboratory space in Chicago, Illinois (the “Chicago Lease”). The original term (the “Original Term”) of the Chicago Lease is 10 years, commencing on July 1, 2020 (the “Commencement Date”), which is the date the premises were ready for occupancy under the terms of the Chicago Lease. The Company has options to extend the term of the Chicago Lease for two additional successive periods of five years each (the “Extension Periods”) at the then prevailing effective market rental rate. The initial annual base rent during the Original Term is $37.00 per square foot per year, or approximately $1,113 for the first 12-month period of the Original Term, payable in monthly installments beginning on the Commencement Date. Base rent thereafter is subject to annual increases of 3%, for an aggregate amount of $12,761 over the Original Term. The Company must also pay its proportionate share of certain operating expenses and taxes for each calendar year during the term. During the first 12-month period of the Original Term, the base rent and the Company's proportionate share of operating expenses and taxes are subject to certain abatements. The Landlord will contribute a maximum of $3,159 toward tenant improvements. In connection with the Chicago Lease, the Company will maintain a letter of credit for the benefit of the Landlord in an initial amount of $1,200, which amount is subject to reduction over time. Upon execution of the Chicago Lease, the Company paid to the Landlord the first installment of base rent and the estimated monthly amount of its pro rata share of taxes and its pro rata share of operating expenses in the aggregate amount of $87 which amount had been adjusted for the abatement as set forth in the lease agreement. Prior to the Commencement Date, the Company also paid the landlord approximately $736 toward tenant improvements. As part of the agreement for the Chicago Lease, the Company is required to maintain a standby letter of credit during the term of the lease, currently in the amount of $1,200, which is secured by a restricted certificate of deposit account and presented within other noncurrent assets on the Company’s unaudited condensed consolidated balance sheet at June 30, 2020. The Chicago Lease has not yet commenced for accounting purposes as of June 30, 2020. As a result, the Company has not yet recognized an operating lease asset or operating lease liability on the unaudited condensed consolidated balance sheet for the Chicago Lease. Skokie Lease The Company’s lease agreement for office and laboratory space in Skokie, Illinois commenced in March 2012 and expires in February 2021 (the “Skokie Lease”). In connection with the Company’s relocation of its headquarters from Skokie, Illinois to its new facility in Chicago, Illinois on July 1, 2020, the Company determined that the remaining useful life of the operating lease asset underlying the Skokie Lease at June 30, 2020 was zero Maturities of the Company’s lease liability as of June 30, 2020 were as follows: Years Ending December 31, Operating Leases (1) 2020 (remaining six months) $ 147 2021 59 Total $ 206 Less: imputed interest (10) Total lease liability $ 196 Current operating lease liability $ 196 (1) Excluded from the table above are the lease payments associated with the Chicago Lease that has not commenced as of the end of the period, which is July 1, 2020 (the date the asset was made available to the Company by the lessor).

Stockholders' Equity

Stockholders' Equity	6 Months Ended
	Jun. 30, 2020
Equity [Abstract]
Stockholders' Equity	Stockholders’ Equity Preferred Stock As of June 30, 2020 and December 31, 2019, the Company had 10,000,000 shares of preferred stock, par value $0.0001 authorized and no shares issued and outstanding. Common Stock As of June 30, 2020 and December 31, 2019, the Company had authorized 200,000,000 shares of common stock, par value $0.0001. As of June 30, 2020 and December 31, 2019, the Company had 87,206,346 shares and 86,069,263 shares issued and outstanding, respectively. The holders of shares of the Company’s common stock are entitled to one vote per share on all matters to be voted upon by the Company’s stockholders and there are no cumulative rights. Subject to preferences that may be applicable to any outstanding preferred stock, the holders of shares of the Company’s common stock are entitled to receive ratably any dividends that may be declared from time to time by the Company’s Board out of funds legally available for that purpose. In the event of the Company’s liquidation, dissolution or winding up, the holders of shares of the Company’s common stock are entitled to share ratably in all assets remaining after payment of liabilities, subject to prior distribution rights of preferred stock then outstanding. The Company’s common stock has no preemptive or conversion rights or other subscription rights. There are no redemption or sinking fund provisions applicable to the Company’s common stock. The outstanding shares of the Company’s common stock are fully paid and non-assessable. December 2019 Offering On December 23, 2019, the Company sold 10,000,000 shares of its common stock at the public offering price of $2.75 per share in an underwritten public offering, for gross proceeds of $27,500 and estimated net proceeds of $25,344 after deducting underwriting discounts and commission and other offering expenses payable by the Company (the “December 2019 Offering”). In addition, the Company granted the underwriters a 30-day option to purchase an additional 1,500,000 shares of common stock offered in the common stock offering. On January 6, 2020, the underwriters partially exercised the option to purchase an additional 1,081,184 shares of common stock at the public offering price of $2.75 per share for additional gross proceeds of $2,973 and net proceeds of $2,766 after deducting underwriting discounts and commission and other offering expenses. The shares sold in the December 2019 Offering were sold pursuant to a registration statement on Form S-3 that was declared effective by the SEC on July 24, 2019. Common Stock Warrants As of June 30 2020, warrants to purchase 413,320 shares of common stock at a price of $3.00 per share remain outstanding. The Warrants expire as follows: 163,174 warrants expire on March 27, 2021; 132,884 expire on April 28, 2021; and 117,262 expire on May 3, 2021. The Warrants are classified as a liability which is remeasured each period at fair value. See Note 12, Fair Value Measurements for more information on the fair value of the common stock warrant liability. Accumulated Other Comprehensive Income (Loss) The following table summarizes the changes in each component of accumulated other comprehensive income (loss), net of tax, for 2020: Unrealized gains (losses) on short-term investments Total Balance at December 31, 2019 $ (27) $ (27) Other comprehensive income (loss) before reclassifications 10 10 Net current period other comprehensive income 10 10 Balance at March 31, 2020 $ (17) $ (17) Other comprehensive income (loss) before reclassifications 352 352 Net losses (gains) reclassified from accumulated other comprehensive loss 3 3 Net current period other comprehensive income 355 355 Balance at June 30, 2020 $ 338 $ 338 The net loss reclassified from accumulated other comprehensive loss resulted from sales of available-for-sale securities prior to maturity. The gross realized gains and gross realized losses of these sales were $23 and $6, respectively, for the three months ended June 30, 2020. The basis on which the cost of the securities was determined was specific identification. Proceeds related to these sales were $9,404.

Equity-Based Compensation

Equity-Based Compensation	6 Months Ended
	Jun. 30, 2020
Share-based Payment Arrangement [Abstract]
Equity-Based Compensation	Equity-Based Compensation The number of shares of common stock reserved for issuance under the 2017 Equity Incentive Plan automatically increases on January 1 of each year, beginning on January 1, 2020, by the lesser of (i) 4,600,000 shares, (ii) 5% of the total number of shares of our capital stock outstanding on December 31 of the preceding calendar year, or (iii) a lesser number of shares determined by the Compensation Committee of the Company’s Board. The Compensation Committee made the determination to increase the share reserve for the 2017 Equity Incentive Plan by 4,303,463 shares, effective January 1, 2020. As of June 30, 2020, the aggregate number of common stock options available for grant under the 2017 Equity Incentive Plan was 2,283,019. Equity-based compensation expense is classified in the statements of operations as follows: Three Months Ended Six Months Ended 2020 2019 2020 2019 Research and development expense $ 203 $ 103 $ 360 $ 224 General and administrative expense 341 336 625 704 $ 544 $ 439 $ 985 $ 928 Unamortized equity-based compensation expense at June 30, 2020 was $4,893, which is expected to be amortized over a weighted-average period of 2.9 years. The Company utilizes the Black-Scholes option-pricing model to determine the fair value of common stock option grants. The Black-Scholes option-pricing model was developed for use in estimating the fair value of traded options that have no vesting restrictions and are fully transferable. The model also requires the input of highly subjective assumptions. In addition to an assumption on the expected term of the option grants as discussed below, application of the Black-Scholes model requires additional inputs for which we have assumed the values described in the table below: Six Months Ended 2020 2019 Expected term 5.2 to 6.1 years 5.3 to 6.1 years Risk-free interest rate 0.41% to 1.68%; weighted avg. 0.67% 1.86% to 2.56%; weighted avg. 2.34% Expected volatility 81.0% to 85.8%; weighted avg. 83.8% 83.2% to 86.7%; weighted avg. 84.4% Forfeiture rate 5 % 5 % Expected dividend yield — % — % The expected term is based upon the “simplified method” as described in Staff Accounting Bulletin Topic 14.D.2. Currently, the Company does not have sufficient experience to provide a reasonable estimate of an expected term of its common stock options. The Company will continue to use the “simplified method” until there is sufficient experience to provide a more reasonable estimate in conformance with ASC 718-10-30-25 through 30-26. The risk-free interest rate assumptions were based on the U.S. Treasury bond rate appropriate for the expected term in effect at the time of grant. The expected volatility is based on calculated enterprise value volatilities for publicly traded companies in the same industry and general stage of development. The estimated forfeiture rates were based on historical experience for similar classes of employees. The dividend yield was based on expected dividends at the time of grant. The fair value of the underlying common stock and the exercise price for the common stock options granted during the six months ended June 30, 2020 and 2019 are summarized in the table below: Common Stock Options Granted During Period Ended: Fair Value of Underlying Common Stock Exercise Price of Common Stock Option Six months ended June 30, 2020 $1.19 to $2.80; weighted avg. $1.85 $1.19 to $2.80; weighted avg. $1.85 Six months ended June 30, 2019 $2.78 to $2.80: weighted avg. $2.79 $2.78 to $2.80: weighted avg. $2.79 The weighted-average grant date fair value of common stock options granted in the six months ended June 30, 2020 and 2019 was $1.29 and $1.99 per common stock option, respectively. A summary of common stock option activity as of the periods indicated is as follows: Options Weighted-Average Exercise Price Weighted-Average Remaining Contractual Term (years) Aggregate Intrinsic Value (thousands) Outstanding - December 31, 2019 5,697,714 $ 2.34 6.7 $ 4,625 Granted 2,075,248 1.85 Exercised (55,899) 0.89 Forfeited (18,750) 2.78 Outstanding - June 30, 2020 7,698,313 $ 2.22 7.2 $ 4,738 Exercisable - June 30, 2020 4,372,185 $ 2.12 5.5 $ 3,351 Vested and Expected to Vest - 7,442,992 $ 2.22 7.1 $ 4,613

Income Taxes

Income Taxes	6 Months Ended
	Jun. 30, 2020
Income Tax Disclosure [Abstract]
Income Taxes	Income TaxesThe Company incurred a pretax loss in each of the three and six months ended June 30, 2020 and 2019, which consists entirely of loss in the United States and resulted in no provision for income tax expense during the periods then ended. The effective tax rate is 0% in each of the three and six months ended June 30, 2020 and 2019 because the Company has generated tax losses and has provided a full valuation allowance against its deferred tax assets.On March 27, 2020, the President of the United States signed into law the Coronavirus Aid, Relief, and Economic Security Act (the “CARES Act”). The CARES Act, among other things, allows for a five-year carry back of federal net operating losses generated in 2018 through 2020 and removes the 80% taxable income limitation for net operating loss deductions for tax years ending before 2021.

Loss Per Common Share

Loss Per Common Share	6 Months Ended
	Jun. 30, 2020
Earnings Per Share [Abstract]
Loss Per Common Share	Loss Per Common ShareBasic loss per common share is calculated by dividing net loss by the weighted-average number of shares of common stock outstanding during the period. Diluted loss per common share is calculated using the treasury share method by giving effect to all potentially dilutive securities that were outstanding. Potentially dilutive options and warrants to purchase common stock that were outstanding during the periods presented were excluded from the diluted loss per share calculation for the periods presented because such shares had an anti-dilutive effect due to the net loss reported in those periods. Therefore, basic and diluted loss per common share is the same for each of the three and six months ended June 30, 2020 and 2019. The following is the computation of loss per common share for the three and six months ended June 30, 2020 and 2019: Three Months Ended Six Months Ended 2020 2019 2020 2019 Net loss $ (4,311) $ (5,220) $ (3,161) $ (10,506) Weighted-average basic and diluted common shares outstanding 87,174,533 44,368,174 87,126,847 44,363,115 Basic and diluted loss per common share $ (0.05) $ (0.12) $ (0.04) $ (0.24) The outstanding securities presented below were excluded from the calculation of loss per common share for the periods presented, because such securities would have been anti-dilutive due to the Company’s loss per share during that period: As of June 30, 2020 2019 Options to purchase common stock 7,698,313 5,078,873 Warrants to purchase common stock 413,320 413,320

Fair Value Measurements

Fair Value Measurements	6 Months Ended
	Jun. 30, 2020
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements ASC Topic 820, Fair Value Measurement , establishes a three-tier fair value hierarchy, which prioritizes the inputs used in measuring fair value, as follows: Level 1 Inputs - unadjusted quoted prices in active markets for identical assets or liabilities accessible to the reporting entity at the measurement date; Level 2 Inputs - other than quoted prices included in Level 1 inputs that are observable for the asset or liability, either directly or indirectly, for substantially the full term of the asset or liability; and Level 3 Inputs - unobservable inputs for the asset or liability used to measure fair value to the extent that observable inputs are not available, thereby allowing for situations in which there is little, if any, market activity for the asset or liability at measurement date. Assets and liabilities measured at fair value on a recurring basis as of June 30, 2020 are as follows: Total Level 1 Level 2 Level 3 Assets Cash equivalents: Money market funds $ 7,602 $ 7,602 $ — $ — Short-term investments: Commercial paper 15,188 — 15,188 — Corporate notes/bonds 45,065 — 45,065 — U.S. Treasuries 2,275 — 2,275 — U.S. government agency securities 6,051 — 6,051 — Total financial assets $ 76,181 $ 7,602 $ 68,579 $ — Liabilities Common stock warrant liability $ 257 $ — $ — $ 257 Total financial liabilities $ 257 $ — $ — $ 257 Assets and liabilities measured at fair value on a recurring basis as of December 31, 2019 are as follows: Total Level 1 Level 2 Level 3 Assets Cash equivalents: Money market funds $ 31,078 $ 31,078 $ — $ — Commercial paper 2,498 — 2,498 — Short-term investments: Commercial paper 11,433 — 11,433 — Corporate notes/bonds 36,597 — 36,597 — U.S. Treasuries 4,512 — 4,512 — U.S. government agency securities 9,784 — 9,784 — Total financial assets $ 95,902 $ 31,078 $ 64,824 $ — Liabilities Common stock warrant liability $ 414 $ — $ — $ 414 Total financial liabilities $ 414 $ — $ — $ 414 The Company uses the market approach and Level 1 and Level 2 inputs to value its cash equivalents and Level 2 inputs to value its short-term investments. The Company’s common stock warrant liability (refer to Note 8, Stockholders’ Equity , for more information) is classified within Level 3 of the fair value hierarchy. The fair value of the common stock warrant liability was determined using the Black-Scholes option-pricing model. The fair value of the common stock warrant liability is based significantly on the fair value of the Company’s common stock. At the date of issuance, the common stock warrant liability was determined using the following weighted-average assumptions: expected term of 2.0 years, risk-free interest rate of 1.53%, expected volatility of 78.97%, and no expected dividends. The following weighted-average assumptions were used to estimate the fair value of the common stock warrant liability at June 30, 2020: June 30, Expected term 0.8 years Risk-free interest rate 0.2 % Expected volatility 93.09 % Expected dividend yield — % A 10% change in the estimate of expected volatility at June 30, 2020 would increase or decrease the fair value of the common stock warrant liability in the amount of $33. A 10% change in the estimate of fair value of the common stock at June 30, 2020 would increase or decrease the fair value of the common stock warrant liability in the amount of $59. The following is a reconciliation of the Company’s liabilities measured at fair value on a recurring basis using unobservable inputs (Level 3) for the three months ended June 30, 2020: Fair Value Measurements Using Significant Unobservable Inputs (Level 3) Common Stock Warrant Liability Balance at December 31, 2019 $ 414 Additions Gain included in other income (expense), net (157) Balance at June 30, 2020 $ 257

Commitment and Contingencies

Commitment and Contingencies	6 Months Ended
	Jun. 30, 2020
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Leases Refer to Note 7, Leases , for a discussion of the commitments associated with the Company’s lease agreements. Northwestern University License Agreements

Related-Party Transactions

Related-Party Transactions	6 Months Ended
	Jun. 30, 2020
Related Party Transactions [Abstract]
Related-Party Transactions	Related-Party TransactionsThe Company received consulting services from, and paid fees to, one of its co-founders who is not an employee but serves as a member of the Board. The Company paid $50 in each of the six months ended June 30, 2020 and 2019 in connection with these consulting services and these amounts are recognized as an expense in the accompanying unaudited condensed consolidated statement of operations.

Subsequent Events

Subsequent Events	6 Months Ended
	Jun. 30, 2020
Subsequent Events [Abstract]
Subsequent Events	Subsequent EventsThe Company has evaluated subsequent events which may require adjustment to or disclosure in the accompanying unaudited condensed consolidated financial statements and has concluded that there are no subsequent events or transactions that occurred subsequent to the balance sheet date that would require recognition or disclosure in the accompanying unaudited condensed consolidated financial statements.

Significant Accounting Polici_2

Significant Accounting Policies (Policies)	6 Months Ended
	Jun. 30, 2020
Accounting Policies [Abstract]
Basis of presentation	Basis of Presentation The accompanying unaudited condensed consolidated financial statements as of June 30, 2020 and December 31, 2019, and for the three and six months ended June 30, 2020 and 2019, have been presented in conformity with generally accepted accounting principles in the United States (“GAAP”).
Principles of consolidation	Principles of Consolidation The accompanying unaudited condensed consolidated financial statements include the accounts of Exicure, Inc. and its wholly owned subsidiary, Exicure Operating Company. All intercompany transactions and accounts are eliminated in consolidation.
Use of estimates	Use of Estimates The preparation of the financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Management bases its estimates on certain assumptions which it believes are reasonable in the circumstances and while actual results could differ from those estimates, management does not believe that any change in those assumptions in the near term would have a significant effect on the Company’s financial position, results of operations or cash flows. Actual results in future periods could differ from those estimates.
Recent accounting pronouncements	The Company’s significant accounting policies are disclosed in the audited consolidated financial statements and the notes thereto, which are included in the in the Company’s Annual Report on Form 10-K for the year ended December 31, 2019 filed with the U.S. Securities and Exchange Commission (“SEC”) on March 10, 2020. Since the date of those audited consolidated financial statements, there have been no material changes to the Company’s significant accounting policies. Recently Adopted Accounting Pronouncements None. Recent Accounting Pronouncements Not Yet Adopted Financial Instruments - Credit Losses In June 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) ASU 2016-13, Measurement of Credit Losses on Financial Instruments (“ASU 2016-13) . ASU 2016-13 is a new standard intended to improve reporting requirements specific to loans, receivables and other financial instruments. ASU 2016-13 requires that credit losses on financial assets measured at amortized cost be determined using an expected loss model, instead of the current incurred loss model, and requires that credit losses related to available-for-sale debt securities be recorded through an allowance for credit losses and limited to the amount by which carrying value exceeds fair value. ASU 2016-13 also requires enhanced disclosure of credit risk associated with financial assets. The effective date of ASU 2016-13 was deferred by ASU 2019-10, Financial Instruments—Credit Losses (Topic 326), Derivatives and Hedging (Topic 815), and Leases (Topic 842)—Effective Dates to the annual period beginning after December 15, 2022 for companies that (i) meet the definition of an SEC filer and (ii) are eligible as “smaller reporting companies” as such term is defined by the SEC, with early adoption permitted. The Company is currently assessing the impact of adoption of ASU 2016-13 to its consolidated financial statements.
Loss per common share	Basic loss per common share is calculated by dividing net loss by the weighted-average number of shares of common stock outstanding during the period. Diluted loss per common share is calculated using the treasury share method by giving effect to all potentially dilutive securities that were outstanding. Potentially dilutive options and warrants to purchase common stock that were outstanding during the periods presented were excluded from the diluted loss per share calculation for the periods presented because such shares had an anti-dilutive effect due to the net loss reported in those periods.

Supplemental Balance Sheet In_2

Supplemental Balance Sheet Information (Tables)	6 Months Ended
	Jun. 30, 2020
Supplemental Balance Sheet Information [Abstract]
Prepaid Expense and Other Current Assets	Prepaid expenses and other current assets June 30, December 31, Prepaid clinical, contract research and manufacturing costs $ 2,203 $ 481 Interest receivable 221 236 Prepaid insurance 212 533 Other 952 705 Prepaid expenses and other current assets $ 3,588 $ 1,955
Property and Equipment, Net	Property and equipment, net June 30, December 31, Scientific equipment $ 3,315 $ 2,795 Leasehold improvements 192 192 Computers and software 48 32 Furniture and fixtures 41 41 Construction in process 2,512 356 Property and equipment, gross 6,108 3,416 Less: accumulated depreciation (1,644) (1,317) Property and equipment, net $ 4,464 $ 2,099
Other Noncurrent Assets	Other noncurrent assets June 30, December 31, Restricted cash $ 1,200 $ — Prepaid lease costs 823 — Prepaid services 233 — Operating lease asset — 356 Other 10 32 Total other noncurrent assets $ 2,266 $ 388
Accrued Expenses and Other Current Liabilities	Accrued expenses and other current liabilities June 30, December 31, Accrued payroll-related expenses $ 706 $ 920 Accrued legal expenses 362 254 Accrued clinical, contract research and manufacturing costs 303 515 Common stock warrant liability 257 — Operating lease liability 196 292 Accrued other expenses 123 454 Accrued expenses and other current liabilities $ 1,947 $ 2,435
Other Noncurrent Liabilities	Other noncurrent liabilities June 30, December 31, Operating lease liability $ — $ 59 Total other noncurrent liabilities $ — $ 59

Investments (Tables)

Investments (Tables)	6 Months Ended
	Jun. 30, 2020
Investments [Abstract]
Investments	The following table summarizes the contract maturity of the available-for-sale securities the Company held as of June 30, 2020: One year or less 92 % After one year but within two years 8 % Total 100 %
Debt Securities, Available-for-sale	The amortized cost, gross unrealized holding gains, gross unrealized holding losses and fair value of cash equivalents and available-for-sale securities by type of security at June 30, 2020 and December 31, 2019 were as follows: June 30, 2020 Amortized Costs Gross Unrealized Holding Gains Gross Unrealized Holding Losses Fair Value Commercial paper $ 15,166 $ 22 $ — $ 15,188 Corporate notes/bonds 44,798 271 (4) 45,065 U.S. Treasuries 2,257 18 — 2,275 U.S. Government agency securities 6,020 31 — 6,051 $ 68,241 $ 342 $ (4) $ 68,579 December 31, 2019 Amortized Costs Gross Unrealized Holding Gains Gross Unrealized Holding Losses Fair Value Commercial paper $ 13,932 $ 1 $ (2) $ 13,931 Corporate notes/bonds 36,620 1 (24) 36,597 U.S. Treasuries 4,513 — (1) 4,512 U.S. Government agency securities 9,786 — (2) 9,784 $ 64,851 $ 2 $ (29) $ 64,824

Leases (Tables)

Leases (Tables)	6 Months Ended
	Jun. 30, 2020
Leases [Abstract]
Schedule of Future Minimum Rental Payments	Maturities of the Company’s lease liability as of June 30, 2020 were as follows: Years Ending December 31, Operating Leases (1) 2020 (remaining six months) $ 147 2021 59 Total $ 206 Less: imputed interest (10) Total lease liability $ 196 Current operating lease liability $ 196 (1) Excluded from the table above are the lease payments associated with the Chicago Lease that has not commenced as of the end of the period, which is July 1, 2020 (the date the asset was made available to the Company by the lessor).

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	6 Months Ended
	Jun. 30, 2020
Equity [Abstract]
Schedule of Accumulated Other Comprehensive Income (Loss)	The following table summarizes the changes in each component of accumulated other comprehensive income (loss), net of tax, for 2020: Unrealized gains (losses) on short-term investments Total Balance at December 31, 2019 $ (27) $ (27) Other comprehensive income (loss) before reclassifications 10 10 Net current period other comprehensive income 10 10 Balance at March 31, 2020 $ (17) $ (17) Other comprehensive income (loss) before reclassifications 352 352 Net losses (gains) reclassified from accumulated other comprehensive loss 3 3 Net current period other comprehensive income 355 355 Balance at June 30, 2020 $ 338 $ 338

Equity-Based Compensation (Tabl

Equity-Based Compensation (Tables)	6 Months Ended
	Jun. 30, 2020
Share-based Payment Arrangement [Abstract]
Equity-Based Compensation Expense Classification in Statement of Operations	Equity-based compensation expense is classified in the statements of operations as follows: Three Months Ended Six Months Ended 2020 2019 2020 2019 Research and development expense $ 203 $ 103 $ 360 $ 224 General and administrative expense 341 336 625 704 $ 544 $ 439 $ 985 $ 928
Assumptions Used to Determine Fair Value of Common Stock Option Grants	In addition to an assumption on the expected term of the option grants as discussed below, application of the Black-Scholes model requires additional inputs for which we have assumed the values described in the table below: Six Months Ended 2020 2019 Expected term 5.2 to 6.1 years 5.3 to 6.1 years Risk-free interest rate 0.41% to 1.68%; weighted avg. 0.67% 1.86% to 2.56%; weighted avg. 2.34% Expected volatility 81.0% to 85.8%; weighted avg. 83.8% 83.2% to 86.7%; weighted avg. 84.4% Forfeiture rate 5 % 5 % Expected dividend yield — % — % The fair value of the underlying common stock and the exercise price for the common stock options granted during the six months ended June 30, 2020 and 2019 are summarized in the table below: Common Stock Options Granted During Period Ended: Fair Value of Underlying Common Stock Exercise Price of Common Stock Option Six months ended June 30, 2020 $1.19 to $2.80; weighted avg. $1.85 $1.19 to $2.80; weighted avg. $1.85 Six months ended June 30, 2019 $2.78 to $2.80: weighted avg. $2.79 $2.78 to $2.80: weighted avg. $2.79
Common Stock Option Activity	A summary of common stock option activity as of the periods indicated is as follows: Options Weighted-Average Exercise Price Weighted-Average Remaining Contractual Term (years) Aggregate Intrinsic Value (thousands) Outstanding - December 31, 2019 5,697,714 $ 2.34 6.7 $ 4,625 Granted 2,075,248 1.85 Exercised (55,899) 0.89 Forfeited (18,750) 2.78 Outstanding - June 30, 2020 7,698,313 $ 2.22 7.2 $ 4,738 Exercisable - June 30, 2020 4,372,185 $ 2.12 5.5 $ 3,351 Vested and Expected to Vest - 7,442,992 $ 2.22 7.1 $ 4,613

Loss Per Common Share (Tables)

Loss Per Common Share (Tables)	6 Months Ended
	Jun. 30, 2020
Earnings Per Share [Abstract]
Computation of earnings (loss) per common share	The following is the computation of loss per common share for the three and six months ended June 30, 2020 and 2019: Three Months Ended Six Months Ended 2020 2019 2020 2019 Net loss $ (4,311) $ (5,220) $ (3,161) $ (10,506) Weighted-average basic and diluted common shares outstanding 87,174,533 44,368,174 87,126,847 44,363,115 Basic and diluted loss per common share $ (0.05) $ (0.12) $ (0.04) $ (0.24)
Antidilutive Securities	The outstanding securities presented below were excluded from the calculation of loss per common share for the periods presented, because such securities would have been anti-dilutive due to the Company’s loss per share during that period: As of June 30, 2020 2019 Options to purchase common stock 7,698,313 5,078,873 Warrants to purchase common stock 413,320 413,320

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	6 Months Ended
	Jun. 30, 2020
Fair Value Disclosures [Abstract]
Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis	Assets and liabilities measured at fair value on a recurring basis as of June 30, 2020 are as follows: Total Level 1 Level 2 Level 3 Assets Cash equivalents: Money market funds $ 7,602 $ 7,602 $ — $ — Short-term investments: Commercial paper 15,188 — 15,188 — Corporate notes/bonds 45,065 — 45,065 — U.S. Treasuries 2,275 — 2,275 — U.S. government agency securities 6,051 — 6,051 — Total financial assets $ 76,181 $ 7,602 $ 68,579 $ — Liabilities Common stock warrant liability $ 257 $ — $ — $ 257 Total financial liabilities $ 257 $ — $ — $ 257 Assets and liabilities measured at fair value on a recurring basis as of December 31, 2019 are as follows: Total Level 1 Level 2 Level 3 Assets Cash equivalents: Money market funds $ 31,078 $ 31,078 $ — $ — Commercial paper 2,498 — 2,498 — Short-term investments: Commercial paper 11,433 — 11,433 — Corporate notes/bonds 36,597 — 36,597 — U.S. Treasuries 4,512 — 4,512 — U.S. government agency securities 9,784 — 9,784 — Total financial assets $ 95,902 $ 31,078 $ 64,824 $ — Liabilities Common stock warrant liability $ 414 $ — $ — $ 414 Total financial liabilities $ 414 $ — $ — $ 414
Schedule of Assumptions Used to Estimate Fair Value of Warrant Liability	The following weighted-average assumptions were used to estimate the fair value of the common stock warrant liability at June 30, 2020: June 30, Expected term 0.8 years Risk-free interest rate 0.2 % Expected volatility 93.09 % Expected dividend yield — %
Reconciliation of Liabilities Measured at Fair Value on a Recurring Basis	The following is a reconciliation of the Company’s liabilities measured at fair value on a recurring basis using unobservable inputs (Level 3) for the three months ended June 30, 2020: Fair Value Measurements Using Significant Unobservable Inputs (Level 3) Common Stock Warrant Liability Balance at December 31, 2019 $ 414 Additions Gain included in other income (expense), net (157) Balance at June 30, 2020 $ 257

Description of Business and B_2

Description of Business and Basis of Presentation (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2020USD ($)ft²
Accounting Policies [Abstract]
Lease area | ft²	30,000
Accumulated deficit generated, since inception | $	$ (103,295)

Collaborative Research and Li_2

Collaborative Research and License Agreements (Details) $ in Thousands	Nov. 13, 2019USD ($)agreements	Feb. 17, 2019USD ($)target	Jun. 30, 2020USD ($)	Jun. 30, 2019USD ($)	Jun. 30, 2020USD ($)	Jun. 30, 2019USD ($)	Dec. 31, 2019USD ($)
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Collaboration revenue			$ 4,847	$ 434	$ 14,030	$ 459
Current portion of deferred revenue							$ 21,873
Allergan Collaboration | Collaboration Arrangement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Number of collaboration programs | agreements	2
Non-refundable upfront payment received for research agreement	$ 25,000
Collaboration option exercise fee	10,000
Collaboration option exercise fee	$ 10,000
Termination period upon written notice	90 days
Collaboration revenue			4,833		13,949
Current portion of deferred revenue			10,880		10,880
Dermelix License Agreement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Aggregate regulatory milestone revenue		$ 13,500
Potential milestone revenue		152,500
Dermelix License Agreement | Collaboration Arrangement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Non-refundable upfront payment received for research agreement		1,000
Collaboration option exercise fee		$ 1,000
Collaboration revenue			$ 14	$ 434	$ 81	$ 459
Number of additional collaboration targets | target		5
Collaboration agreement term		6 years
Collaboration development expenses		$ 1,000
Collaboration option rights usage term		30 days
Development and Commercialization License | Allergan Collaboration | Collaboration Arrangement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Collaboration option exercise fee	$ 15,000
Maximum | Allergan Collaboration | Collaboration Arrangement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Development milestone payment	55,000
Product approval and launch milestone payment	132,500
Sales milestone payment	$ 175,000

Supplemental Balance Sheet In_3

Supplemental Balance Sheet Information - Prepaid expenses and other current assets (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Supplemental Balance Sheet Information [Abstract]
Prepaid clinical, contract research and manufacturing costs	$ 2,203	$ 481
Interest receivable	221	236
Prepaid insurance	212	533
Other	952	705
Prepaid expenses and other current assets	$ 3,588	$ 1,955

Supplemental Balance Sheet In_4

Supplemental Balance Sheet Information - Property and Equipment, Net (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 6,108		$ 6,108		$ 3,416
Less: accumulated depreciation	(1,644)		(1,644)		(1,317)
Property and equipment, net	4,464		4,464		2,099
Depreciation and amortization	187	$ 87	335	$ 174
Scientific equipment
Property, Plant and Equipment [Line Items]
Property and equipment, gross	3,315		3,315		2,795
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property and equipment, gross	192		192		192
Computers and software
Property, Plant and Equipment [Line Items]
Property and equipment, gross	48		48		32
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Property and equipment, gross	41		41		41
Construction in process
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 2,512		$ 2,512		$ 356

Supplemental Balance Sheet In_5

Supplemental Balance Sheet Information - Other noncurrent assets (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Supplemental Balance Sheet Information [Abstract]
Restricted cash	$ 1,200	$ 0
Prepaid lease costs	823	0
Prepaid services	233	0
Operating lease asset	0	356
Other	10	32
Total other noncurrent assets	$ 2,266	$ 388

Supplemental Balance Sheet In_6

Supplemental Balance Sheet Information - Accrued Expense and Other Current Liabilities (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Supplemental Balance Sheet Information [Abstract]
Accrued payroll-related expenses	$ 706	$ 920
Accrued legal expenses	362	254
Operating lease liability	196	292
Common stock warrant liability	257	0
Accrued clinical, contract research and manufacturing costs	303	515
Accrued other expenses	123	454
Accrued expenses and other current liabilities	$ 1,947	$ 2,435

Supplemental Balance Sheet In_7

Supplemental Balance Sheet Information - Other noncurrent liabilities (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Supplemental Balance Sheet Information [Abstract]
Operating lease liability	$ 0	$ 59
Other noncurrent liabilities	$ 0	$ 59

Investments (Details)

Investments (Details)	6 Months Ended
	Jun. 30, 2020
Investments [Abstract]
One year or less	92.00%
After one year but within two years	8.00%
Total	100.00%

Investments Available-for-sale

Investments Available-for-sale Securities (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Debt Securities, Available-for-sale [Line Items]
Amortized costs	$ 68,241	$ 64,851
Gross unrealized holding gains	342	2
Gross unrealized holding losses	(4)	(29)
Fair value	68,579	64,824
Commercial paper
Debt Securities, Available-for-sale [Line Items]
Amortized costs	15,166	13,932
Gross unrealized holding gains	22	1
Gross unrealized holding losses	0	(2)
Fair value	15,188	13,931
Corporate notes/bonds
Debt Securities, Available-for-sale [Line Items]
Amortized costs	44,798	36,620
Gross unrealized holding gains	271	1
Gross unrealized holding losses	(4)	(24)
Fair value	45,065	36,597
U.S. Treasuries
Debt Securities, Available-for-sale [Line Items]
Amortized costs	2,257	4,513
Gross unrealized holding gains	18	0
Gross unrealized holding losses	0	(1)
Fair value	2,275	4,512
U.S. Government agency securities
Debt Securities, Available-for-sale [Line Items]
Amortized costs	6,020	9,786
Gross unrealized holding gains	31	0
Gross unrealized holding losses	0	(2)
Fair value	$ 6,051	$ 9,784

Debt - Narrative (Details)

Debt - Narrative (Details) - USD ($) $ in Thousands	Mar. 02, 2020	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Debt Instrument [Line Items]
Repayment of long-term debt				$ 4,999	$ 0
Interest paid on debt		$ 0	$ 152	$ 142	$ 301
Loans Payable | Secured Debt | Hercules Technology Growth Capital
Debt Instrument [Line Items]
Repayment of long-term debt	$ 4,999
Payments for debt end term fees	$ 100

Leases - Narrative (Details)

Leases - Narrative (Details) $ in Thousands	Feb. 28, 2020USD ($)numberOfPeriods$ / squarefeet	Jun. 30, 2020USD ($)	Jun. 30, 2020USD ($)ft²
Leases [Abstract]
Lease area | ft²			30,000
Contract term	10 years
Number of extensions | numberOfPeriods	2
Renewal term	5 years
Annual base rate initial twelve months | $ / squarefeet	37
Annual rent payment initial twelve months	$ 1,113
Base rent annual percentage increase	3.00%
Estimated rental payment over original term	$ 12,761
Landlord contribution towards tenant improvement	3,159		$ 736
Letters of credit outstanding	1,200
Rental payment adjusted for abatement	$ 87
Operating lease asset, remaining useful life		0 years
Amortization expense		$ 211

Leases - Schedule of Future Min

Leases - Schedule of Future Minimum Rental Payments (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Leases [Abstract]
2020 (remaining six months)	$ 147
2021	59
Total	206
Less: imputed interest	(10)
Total lease liability	196
Current operating lease liability	$ 196	$ 292

Stockholders' Equity - Current

Stockholders' Equity - Current Capitalization (Details)	Jun. 30, 2020vote_per_share$ / sharesshares	Dec. 31, 2019$ / sharesshares
Equity [Abstract]
Preferred stock, shares authorized (in shares)	10,000,000	10,000,000
Preferred stock, par value (in dollars per share) | $ / shares	$ 0.0001	$ 0.0001
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Common stock, shares authorized (in shares)	200,000,000	200,000,000
Common stock, par value (in dollars per share) | $ / shares	$ 0.0001	$ 0.0001
Common stock, shares issued (in shares)	87,206,346	86,069,263
Common stock, shares outstanding (in shares)	87,206,346	86,069,263
Common stock, voting rights for each share | vote_per_share	1

Stockholders' Equity - 2019 Sto

Stockholders' Equity - 2019 Stock Offerings (Details) - USD ($) $ / shares in Units, $ in Thousands	Jan. 06, 2020	Dec. 23, 2019	Jun. 30, 2020	Jun. 30, 2019
Class of Stock [Line Items]
Proceeds from common stock offering			$ 2,973	$ 0
Common Stock Issued December 2019
Class of Stock [Line Items]
Issuance of stock, net (in shares)		10,000,000
Price per share in sale of stock (in dollars per share)		$ 2.75
Proceeds from common stock offering		$ 27,500
Proceeds from issuance of common stock, net		$ 25,344
Over-Allotment Option
Class of Stock [Line Items]
Issuance of stock, net (in shares)	1,081,184
Proceeds from common stock offering	$ 2,973
Proceeds from issuance of common stock, net	$ 2,766
Additional shares of common stock offered in common stock offering (in shares)		1,500,000

Stockholders' Equity - Common S

Stockholders' Equity - Common Stock Warrants (Details) - $ / shares	May 03, 2021	Apr. 28, 2021	Mar. 27, 2021	Jun. 30, 2020
Class of Stock [Line Items]
Exercise price (in dollars per share)				$ 3
Private Placement
Class of Stock [Line Items]
Number of shares called by warrants (in shares)				413,320
Forecast | Private Placement
Class of Stock [Line Items]
Warrant expirations	117,262	132,884	163,174

Stockholders' Equity - Accumula

Stockholders' Equity - Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Thousands	3 Months Ended			6 Months Ended
	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	$ 85,114	$ 80,747	$ 16,155	$ 80,747	$ 20,952
Other comprehensive income, net	355	10	0	365	0
Ending balance	81,752	85,114	11,391	81,752	11,391
Gross realized gains, available for sale securities	23
Gross realized losses, available for sale securities	6
Proceeds from sale of debt securities, available-for-sale	9,404
Unrealized gains (losses) on short-term investments
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(17)	(27)		(27)
Other comprehensive income (loss) before reclassifications	352	10
Net losses (gains) reclassified from accumulated other comprehensive loss	3
Other comprehensive income, net	355	10
Ending balance	338	(17)		338
AOCI Attributable to Parent
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(17)	(27)	0	(27)	0
Other comprehensive income (loss) before reclassifications	352	10
Net losses (gains) reclassified from accumulated other comprehensive loss	3
Other comprehensive income, net	355	10
Ending balance	$ 338	$ (17)	$ 0	$ 338	$ 0

Equity-Based Compensation - Nar

Equity-Based Compensation - Narrative (Details) - USD ($) $ / shares in Units, $ in Thousands	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jan. 01, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation cost not yet recognized	$ 4,893
Compensation expense recognition period	2 years 10 months 24 days
Weighted-average grant date fair value (in dollars per share)	$ 1.29	$ 1.99
Aggregate intrinsic value, stock options, exercised	$ 89	$ 17
Exicure, Inc. 2017 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of additional shares authorized, potential maximum additional shares	4,600,000
Number of additional shares authorized, percentage of common stock outstanding			5.00%
Number of shares available for grant (in shares)	2,283,019
Options to purchase common stock | Exicure, Inc. 2017 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares available for grant (in shares)			4,303,463

Equity-Based Compensation - Sch

Equity-Based Compensation - Schedule of Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	$ 544	$ 439	$ 985	$ 928
Research and development expense
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	203	103	360	224
General and administrative expense
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	$ 341	$ 336	$ 625	$ 704

Equity-Based Compensation - Ass

Equity-Based Compensation - Assumptions Used for Fair Value Measurement (Details)	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Forfeiture rate	5.00%	5.00%
Expected dividend yield	0.00%	0.00%
Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term	5 years 2 months 12 days	5 years 3 months 18 days
Risk-free interest rate	0.41%	0.0186%
Expected volatility	81.00%	0.832%
Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term	6 years 1 month 6 days	6 years 1 month 6 days
Risk-free interest rate	1.68%	0.0256%
Expected volatility	85.80%	0.867%
Weighted Average
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rate	0.67%	0.0234%
Expected volatility	83.80%	0.844%

Equity-Based Compensation - Fai

Equity-Based Compensation - Fair Value of Underlying Common Stock and Exercise Price of Stock Options (Details) - $ / shares	Jun. 30, 2020	Jun. 30, 2019
Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fair Value of Underlying Common Stock (dollars per share)	$ 1.19	$ 2.78
Exercise Price of Common Stock Option (dollars per share)	1.19	2.78
Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fair Value of Underlying Common Stock (dollars per share)	2.80	2.80
Exercise Price of Common Stock Option (dollars per share)	2.80	2.80
Weighted Average
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fair Value of Underlying Common Stock (dollars per share)	1.85	2.79
Exercise Price of Common Stock Option (dollars per share)	$ 1.85	$ 2.79

Equity-Based Compensation - S_2

Equity-Based Compensation - Schedule of Stock Options Rollforward (Details) $ / shares in Units, $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2020USD ($)$ / sharesshares	Dec. 31, 2019USD ($)$ / sharesshares
Options
Outstanding beginning balance (in shares) | shares	5,697,714
Granted (in shares) | shares	2,075,248
Exercise of options (in shares) | shares	(55,899)
Forfeited (in shares) | shares	(18,750)
Outstanding ending balance (in shares) | shares	7,698,313	5,697,714
Weighted-Average Exercise Price
Outstanding beginning balance (in dollars per share) | $ / shares	$ 2.34
Granted (in dollars per share) | $ / shares	1.85
Exercised (in dollars per share) | $ / shares	0.89
Forfeited (in dollars per share) | $ / shares	2.78
Outstanding ending balance (in dollars per share) | $ / shares	$ 2.22	$ 2.34
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Weighted-Average Remaining Contractual Term (years)	7 years 2 months 12 days	6 years 8 months 12 days
Aggregate Intrinsic Value (thousands) | $	$ 4,738	$ 4,625
Exercisable (in shares) | shares	4,372,185
Exercisable, weighted-average exercise price (in dollars per share) | $ / shares	$ 2.12
Exercisable, weighted-average remaining contractual term	5 years 6 months
Exercisable, aggregate intrinsic value | $	$ 3,351
Vested and expected to vest (in shares) | shares	7,442,992
Vested and expected to vest, weighted-average exercise price (in dollars per share) | $ / shares	$ 2.22
Weighted-Average Remaining Contractual Term (years)	7 years 1 month 6 days
Aggregate Intrinsic Value (thousands) | $	$ 4,613

Income Taxes (Details)

Income Taxes (Details)	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
Income Tax Disclosure [Abstract]
Effective tax rate	0.00%	0.00%

Loss Per Common Share - Computa

Loss Per Common Share - Computation of Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2020	Jun. 30, 2019
Earnings Per Share [Abstract]
Net loss	$ (4,311)	$ 1,150	$ (5,220)	$ (5,286)	$ (3,161)	$ (10,506)
Weighted average basic and diluted common shares outstanding (in shares)	87,174,533		44,368,174		87,126,847	44,363,115
Basic and diluted loss per common share (in usd per share)	$ (0.05)		$ (0.12)		$ (0.04)	$ (0.24)

Loss Per Common Share - Antidil

Loss Per Common Share - Antidilutive Securities (Details) - shares	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
Options to purchase common stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive shares excluded from computation of weighted-average diluted common shares outstanding (in shares)	7,698,313	5,078,873
Warrants to purchase common stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive shares excluded from computation of weighted-average diluted common shares outstanding (in shares)	413,320	413,320

Fair Value Measurements - Asset

Fair Value Measurements - Assets and Liabilities Measured at Fair Value (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities, available-for-sale	$ 68,579	$ 64,824
Fair Value, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total financial assets	76,181	95,902
Common stock warrant liability	257	414
Total financial liabilities	257	414
Fair Value, Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total financial assets	7,602	31,078
Common stock warrant liability	0	0
Total financial liabilities	0	0
Fair Value, Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total financial assets	68,579	64,824
Common stock warrant liability	0	0
Total financial liabilities	0	0
Fair Value, Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total financial assets	0	0
Common stock warrant liability	257	414
Total financial liabilities	257	414
Money market funds | Fair Value, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	7,602	31,078
Money market funds | Fair Value, Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	7,602	31,078
Money market funds | Fair Value, Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	0	0
Money market funds | Fair Value, Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	0	0
Commercial paper | Fair Value, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents		2,498
Commercial paper | Fair Value, Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents		0
Commercial paper | Fair Value, Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents		2,498
Commercial paper | Fair Value, Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents		0
Commercial paper | Fair Value, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities, available-for-sale	15,188	11,433
Commercial paper | Fair Value, Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities, available-for-sale	0	0
Commercial paper | Fair Value, Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities, available-for-sale	15,188	11,433
Commercial paper | Fair Value, Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities, available-for-sale	0	0
Corporate notes/bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities, available-for-sale	45,065	36,597
Corporate notes/bonds | Fair Value, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities, available-for-sale	45,065	36,597
Corporate notes/bonds | Fair Value, Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities, available-for-sale	0	0
Corporate notes/bonds | Fair Value, Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities, available-for-sale	45,065	36,597
Corporate notes/bonds | Fair Value, Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities, available-for-sale	0	0
U.S. Treasuries
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities, available-for-sale	2,275	4,512
U.S. Treasuries | Fair Value, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities, available-for-sale	2,275	4,512
U.S. Treasuries | Fair Value, Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities, available-for-sale	0	0
U.S. Treasuries | Fair Value, Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities, available-for-sale	2,275	4,512
U.S. Treasuries | Fair Value, Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities, available-for-sale	0	0
U.S. Government agency securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities, available-for-sale	6,051	9,784
U.S. Government agency securities | Fair Value, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities, available-for-sale	6,051	9,784
U.S. Government agency securities | Fair Value, Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities, available-for-sale	0	0
U.S. Government agency securities | Fair Value, Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities, available-for-sale	6,051	9,784
U.S. Government agency securities | Fair Value, Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities, available-for-sale	$ 0	$ 0

Fair Value Measurements - Narra

Fair Value Measurements - Narrative (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2020USD ($)	Feb. 17, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impact of 10% change in estimate of expected volatility of the fair value of the common stock	$ 33
Impact of 10% change in the estimate of fair value of the common stock	$ 59
Warrant Liability | Preferred Stock | Expected term
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Warrant liability, measurement input, term		2 years
Warrant Liability | Preferred Stock | Risk-free interest rate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Common stock warrant liability, measurement input		0.0153
Warrant Liability | Preferred Stock | Expected volatility
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Common stock warrant liability, measurement input		0.7897
Warrant Liability | Preferred Stock | Expected dividend yield
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Common stock warrant liability, measurement input		0

Fair Value Measurements - Sched

Fair Value Measurements - Schedule of Assumptions used to Estimate Fair Value of Warrant Liability (Details) - Warrant Liability - Common Stock	Jun. 30, 2020
Expected term
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Warrant liability, measurement input, term	9 months 18 days
Risk-free interest rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Common stock warrant liability, measurement input	0.002
Expected volatility
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Common stock warrant liability, measurement input	0.9309
Expected dividend yield
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Common stock warrant liability, measurement input	0

Fair Value Measurements - Recon

Fair Value Measurements - Reconciliation of Liabilities Measured at Fair Value on a Recurring Basis (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Gain included in other income (expense), net	$ (157)	$ (256)
Fair Value Measurements Using Significant Unobservable Inputs (Level 3) | Common Stock | Warrant Liability
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at December 31, 2019	414
Balance at June 30, 2020	$ 257

Commitment and Contingencies (D

Commitment and Contingencies (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2020USD ($)
Commitments and Contingencies Disclosure [Abstract]
Aggregate consideration paid to NU for agreement obligations	$ 8,229

Related-Party Transactions - Na

Related-Party Transactions - Narrative (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
Board of Directors | Consulting services
Related Party Transaction [Line Items]
Expenses from transactions with related party	$ 50	$ 50