Leap Therapeutics (LPTX) 10-Q 13 Aug 21 2021 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2021	Aug. 10, 2021
Document and Entity Information
Document Type	10-Q
Document Quarterly Report	true
Document Transition Report	false
Document Period End Date	Jun. 30, 2021
Entity File Number	001-37990
Entity Address, Address Line One	47 Thorndike St, Suite B1-1
Entity Address, City or Town	Cambridge
Entity Address, Postal Zip Code	02141
Entity Address, State or Province	MA
Entity Incorporation, State or Country Code	DE
City Area Code	(617)
Local Phone Number	714-0360
Entity Tax Identification Number	27-4412575
Entity Registrant Name	LEAP THERAPEUTICS, INC.
Title of 12(b) Security	Common Stock, par value $0.001 per share
Trading Symbol	LPTX
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	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		59,672,014
Entity Central Index Key	0001509745
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q2
Amendment Flag	false

CONDENSED CONSOLIDATED BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 35,734	$ 52,071
Research and development incentive receivable	22	73
Prepaid expenses and other current assets	264	130
Total current assets	36,020	52,274
Property and equipment, net	50	65
Right of use assets, net	337	528
Research and development incentive receivable, net of current portion	309
Deferred tax assets	176	179
Deferred costs	68	345
Deposits	980	980
Total assets	37,940	54,371
Current liabilities:
Accounts payable	4,343	2,717
Accrued expenses	2,609	2,747
Deferred revenue	750	1,500
Lease liability - current portion	354	408
Total current liabilities	8,056	7,372
Non current liabilities:
Restricted stock liability		204
Lease liability, net of current portion		144
Total liabilities	8,056	7,720
Stockholders' equity:
Common stock, $0.001 par value; 240,000,000 shares authorized; 59,672,014 and 59,657,742 shares issued and outstanding as of June 30,2021 and December 31, 2020, respectively	60	60
Additional paid-in capital	271,918	270,155
Accumulated other comprehensive loss	(449)	(579)
Accumulated deficit	(241,645)	(222,985)
Total stockholders' equity	29,884	46,651
Total liabilities and stockholders' equity	$ 37,940	$ 54,371

CONDENSED CONSOLIDATED BALANC_2

CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Jun. 30, 2021	Dec. 31, 2020
CONDENSED CONSOLIDATED BALANCE SHEETS
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, authorized shares	240,000,000	240,000,000
Common stock, issued shares	59,672,014	59,657,742
Common stock, outstanding shares	59,672,014	59,657,742

CONDENSED CONSOLIDATED STATEMEN

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS
License revenue	$ 375	$ 375	$ 750	$ 750
Operating expenses:
Research and development	7,206	5,350	14,013	9,953
General and administrative	2,795	2,521	5,535	4,674
Total operating expenses	10,001	7,871	19,548	14,627
Loss from operations	(9,626)	(7,496)	(18,798)	(13,877)
Interest income	1	20	3	88
Interest expense	(16)	(13)	(30)	(25)
Australian research and development incentives	244	30	315	115
Foreign currency gain (loss)	(129)	943	(150)	(48)
Loss before income taxes	(9,526)	(6,516)	(18,660)	(13,747)
Dividend attributable to down round feature of warrants				(303)
Dividend attributable to Series A & B convertible preferred stock				(372)
Series A & B convertible preferred stock - beneficial conversion feature				(9,399)
Net loss attributable to common stockholders	$ (9,526)	$ (6,516)	$ (18,660)	$ (23,821)
Net loss per share
Basic and diluted	$ (0.12)	$ (0.12)	$ (0.24)	$ (0.57)
Weighted average common shares outstanding
Basic & diluted	76,389,525	52,442,597	76,384,077	42,037,405

CONDENSED CONSOLIDATED STATEM_2

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS
Net loss	$ (9,526)	$ (6,516)	$ (18,660)	$ (13,747)
Other comprehensive income:
Foreign currency translation adjustments	115	(867)	130	45
Comprehensive loss	$ (9,411)	$ (7,383)	$ (18,530)	$ (13,702)

CONDENSED CONSOLIDATED STATEM_3

CONDENSED CONSOLIDATED STATEMENTS OF CONVERTIBLE PREFERRED STOCK AND STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Series A Convertible Preferred Stock	Series B Convertible Preferred Stock	Series A Convertible Preferred Stock	Series B Convertible Preferred Stock	2020 Public OfferingCommon Stock	2020 Public OfferingAdditional Paid In Capital	2020 Public Offering	Common Stock	Additional Paid In Capital	Accumulated Other Comprehensive Income	Accumulated Deficit	Total
Balance at the beginning of the period (in shares) at Dec. 31, 2019	0	0						24,194,877
Increase (Decrease) in Shares Outstanding
Issuance of Series A & B Convertible Preferred Stock, net of underwriting discounts (in shares)	1,421,801	1,137,442			23,625,000
Issuance of common stock upon exercise of stock options (in shares)								32,778
Issuance of common stock upon exercise of warrant (in shares)								273,954
Conversion of Series A Convertible Preferred Stock to prefunded warrants (in shares)	(1,421,801)
Conversion of Series B Convertible Preferred Stock to common stock (in shares)		(1,137,442)						11,531,133
Balance at the end of the period (in shares) at Jun. 30, 2020	0	0						59,657,742
Balance at the beginning of the period at Dec. 31, 2019	$ 0	$ 0						$ 24	$ 193,319	$ 76	$ (195,168)	$ (1,749)
Increase (Decrease) in Stockholders' Equity
Issuance of Series A & B Convertible Preferred Stock, net of underwriting discounts	14,062	11,260			$ 24	$ 48,252	$ 48,276
Issuance of common stock upon exercise of stock options									50			50
Issuance of common stock upon exercise of warrants									348			348
Series A & B Convertible Preferred Stock discount - beneficial conversion feature	(5,226)	(4,173)	$ 5,226	$ 4,173					9,399			9,399
Series A & B Convertible Preferred Stock accrued dividends	207	165							(372)			(372)
Conversion of Series A & B Convertible Preferred Stock dividends to prefunded warrants and common stock	(207)	(165)							372			372
Conversion of Series A Convertible Preferred Stock to prefunded warrants	(8,836)		$ (8,836)						8,836			8,836
Conversion of Series B Convertible Preferred Stock to common stock		(7,087)						12	7,076			7,088
Dividend attributable to down round feature of 2017 warrants									303		(303)	303
Foreign currency translation adjustment										45		45
Stock-based compensation									1,187			1,187
Net loss											(13,747)	(13,747)
Balance at the end of the period at Jun. 30, 2020	$ 0	$ 0						$ 60	268,770	121	(209,218)	59,733
Balance at the beginning of the period (in shares) at Mar. 31, 2020	0	0						35,799,488
Increase (Decrease) in Shares Outstanding
Issuance of Series A & B Convertible Preferred Stock, net of underwriting discounts (in shares)					23,625,000
Issuance of common stock upon exercise of stock options (in shares)								25,000
Issuance of common stock upon exercise of warrant (in shares)								208,254
Balance at the end of the period (in shares) at Jun. 30, 2020	0	0						59,657,742
Balance at the beginning of the period at Mar. 31, 2020	$ 0	$ 0						$ 36	219,642	988	(202,702)	17,964
Increase (Decrease) in Stockholders' Equity
Issuance of Series A & B Convertible Preferred Stock, net of underwriting discounts					$ 24	$ 48,252	$ 48,276
Issuance of common stock upon exercise of stock options									39			39
Issuance of common stock upon exercise of warrants									220			220
Foreign currency translation adjustment										(867)		(867)
Stock-based compensation									617			617
Net loss											(6,516)	(6,516)
Balance at the end of the period at Jun. 30, 2020	$ 0	$ 0						$ 60	268,770	121	(209,218)	$ 59,733
Balance at the beginning of the period (in shares) at Dec. 31, 2020								59,657,742
Increase (Decrease) in Shares Outstanding
Issuance of common stock upon exercise of stock options (in shares)								2,292				2,292
Issuance of common stock upon exercise of warrant (in shares)								11,980
Balance at the end of the period (in shares) at Jun. 30, 2021								59,672,014
Balance at the beginning of the period at Dec. 31, 2020								$ 60	270,155	(579)	(222,985)	$ 46,651
Increase (Decrease) in Stockholders' Equity
Issuance of common stock upon exercise of stock options									4			4
Issuance of common stock upon exercise of warrants									14			14
Foreign currency translation adjustment										130		130
Stock-based compensation									1,745			1,745
Net loss											(18,660)	(18,660)
Balance at the end of the period at Jun. 30, 2021								$ 60	271,918	(449)	(241,645)	29,884
Balance at the beginning of the period (in shares) at Mar. 31, 2021								59,669,722
Increase (Decrease) in Shares Outstanding
Issuance of common stock upon exercise of stock options (in shares)								2,292
Balance at the end of the period (in shares) at Jun. 30, 2021								59,672,014
Balance at the beginning of the period at Mar. 31, 2021								$ 60	271,002	(564)	(232,119)	38,379
Increase (Decrease) in Stockholders' Equity
Issuance of common stock upon exercise of stock options									4			4
Foreign currency translation adjustment										115		115
Stock-based compensation									912			912
Net loss											(9,526)	(9,526)
Balance at the end of the period at Jun. 30, 2021								$ 60	$ 271,918	$ (449)	$ (241,645)	$ 29,884

CONDENSED CONSOLIDATED STATEM_4

CONDENSED CONSOLIDATED STATEMENTS OF CONVERTIBLE PREFERRED STOCK AND STOCKHOLDERS' EQUITY (Parenthetical) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2020
2020 Public Offering
CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (Parenthetical)
Issuance of common stock, issuance costs	$ 3,472	$ 3,472

CONDENSED CONSOLIDATED STATEM_5

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Cash flows from operating activities:
Net loss			$ (18,660)	$ (13,747)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation expense			14	18
Amortization of contract asset			68	68
Change in right-of-use asset			191	315
Stock-based compensation expense			1,745	1,187
Foreign currency loss	$ 129	$ (943)	150	48
Change in fair value of restricted stock liability			(204)	(159)	$ 204
Changes in operating assets and liabilities:
Prepaid expenses and other assets			(134)	734
Research and development incentive receivable			(258)	(119)
Contract acquisition costs				(270)
Deferred offering costs			209
Accounts payable and accrued expenses			1,488	(3,418)
Deferred revenue			(750)	2,250
Lease liability			(198)	(284)
Net cash used in operating activities			(16,339)	(13,377)
Cash flows from investing activities:
Proceeds from the sale of property and equipment				25
Net cash provided by investing activities				25
Cash flows from financing activities:
Proceeds from issuance of common stock - June 2020 Public Offering				48,518
Proceeds from the exercise of common stock warrants			14	348
Proceeds from the exercise of stock options			4	50
Payment of deferred costs				(1,520)
Net cash provided by financing activities			18	74,382
Effect of exchange rate changes on cash and cash equivalents			(16)	(34)
Net increase (decrease) in cash and cash equivalents			(16,337)	60,996
Cash and cash equivalents at beginning of period			52,071	3,891	3,891
Cash and cash equivalents at end of period	$ 35,734	$ 64,887	$ 35,734	64,887	$ 52,071
Supplemental disclosure of non-cash financing activities:
Dividend attributable to down round feature of warrants				303
Offering costs included in accounts payable and accrued expenses - January 2020 Private Placement				144
Offering costs included in accounts payable and accrued expenses - June 2020 Public Offering				242
Conversion of Series A convertible preferred stock to prefunded warrants				(8,836)
Beneficial conversion feature from Series convertible preferred stock				9,399
Series A Convertible Preferred Stock
Cash flows from financing activities:
Proceeds from the issuance of Series convertible preferred stock				14,986
Supplemental disclosure of non-cash financing activities:
Conversion of Series A convertible preferred stock to prefunded warrants				8,836
Beneficial conversion feature from Series convertible preferred stock				5,226
Series B Convertible Preferred Stock
Cash flows from financing activities:
Proceeds from the issuance of Series convertible preferred stock				12,000
Supplemental disclosure of non-cash financing activities:
Conversion of Series B convertible preferred stock to common stock				7,087
Beneficial conversion feature from Series convertible preferred stock				$ 4,173

Nature of Business, Basis of Pr

Nature of Business, Basis of Presentation and Liquidity	6 Months Ended
	Jun. 30, 2021
Nature of Business, Basis of Presentation and Liquidity
Nature of Business, Basis of Presentation and Liquidity	1. Nature of Business, Basis of Presentation and Liquidity Nature of Business Leap Therapeutics, Inc. was incorporated in the state of Delaware on January 3, 2011. During 2015, HealthCare Pharmaceuticals Pty Ltd. (“HCP Australia”) was formed and is a wholly owned subsidiary of the Company. The Company is a biopharmaceutical company acquiring and developing novel therapeutics at the leading edge of cancer biology. The Company’s approach is designed to target compelling tumor-promoting and immuno-oncology pathways to generate durable clinical benefit and enhanced outcomes for patients. The Company’s programs are monoclonal antibodies that target key cellular pathways that enable cancer to grow and spread and specific mechanisms that activate the body’s immune system to identify and attack cancer. Basis of Presentation The accompanying condensed consolidated financial statements as of June 30, 2021 and for the three and six months ended June 30, 2021 and 2020 have been prepared by the Company, pursuant to the rules and regulations of the Securities and Exchange Commission (the “SEC”) for interim financial statements. Certain information and footnote disclosures normally included in financial statements prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”) have been condensed or omitted pursuant to such rules and regulations. However, the Company believes that the disclosures are adequate to make the information presented not misleading. These condensed consolidated financial statements should be read in conjunction with the Company’s audited consolidated financial statements and the notes thereto for the year ended December 31, 2020 included in the Company’s Annual Report on Form 10-K filed with the SEC on March 12, 2021. The condensed consolidated financial statements have been prepared on the same basis as the audited consolidated financial statements. In the opinion of management, the accompanying condensed consolidated financial statements contain all adjustments which are necessary for the fair presentation of the Company’s financial position as of June 30, 2021, statements of operations and statements of comprehensive loss for the three and six months ended June 30, 2021 and 2020 and statements of cash flows for the six months ended June 30, 2021 and 2020. Such adjustments are of a normal and recurring nature. The results of operations for the three and six months ended June 30, 2021 are not necessarily indicative of the results of operations that may be expected for the year ending December 31, 2021. Liquidity Since inception, the Company has been engaged in organizational activities, including raising capital, and research and development activities. The Company does not yet have a product that has been approved by the Food and Drug Administration (the “FDA”), has not generated any product sales revenues and has not yet achieved profitable operations, nor has it ever generated positive cash flows from operations. There is no assurance that profitable operations, if achieved, could be sustained on a continuing basis. Further, the Company’s future operations are dependent on the success of the Company’s efforts to raise additional capital, its research and commercialization efforts, regulatory approval, and, ultimately, the market acceptance of the Company’s products. ​ In accordance with Accounting Standards Codification (“ASC”) 205-40, Going Concern, the Company has evaluated whether there are conditions and events, considered in the aggregate, that raise substantial doubt about the Company’s ability to continue as a going concern for a period of at least one year after the date that the condensed consolidated financial statements are issued. As of June 30, 2021, the Company had cash and cash equivalents of $35,734. Additionally, the Company had an accumulated deficit of $241,645 at June 30, 2021, and during the six months ended June 30, 2021, the Company incurred a net loss of $18,660. The Company expects to continue to generate operating losses for the foreseeable future. The Company believes that its cash and cash equivalents of $35,734 as of June 30, 2021 will be sufficient to fund its operating expenses for at least the next 12 months from issuance of these financial statements. In addition, the Company will seek additional funding through public or private equity financings or government programs and will seek funding or development program cost-sharing through collaboration agreements or licenses with larger pharmaceutical or biotechnology companies. If the Company does not obtain additional funding or development program costsharing, the Company would be forced to delay, reduce or eliminate certain clinical trials or research and development programs, reduce or eliminate discretionary operating expenses, and delay company and pipeline expansion, which would adversely affect its business prospects. The inability to obtain funding, as and when needed, would have a negative impact on the Company’s financial condition and ability to pursue its business strategies.

Summary of Significant Accounti

Summary of Significant Accounting Policies	6 Months Ended
	Jun. 30, 2021
Summary of Significant Accounting Policies
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies Principles of Consolidation The accompanying condensed consolidated financial statements include the accounts of the Company and its wholly owned subsidiaries. All intercompany accounts and transactions are eliminated upon consolidation. Use of Estimates The presentation of condensed consolidated 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 condensed consolidated financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. Research and development incentive income and receivable The Company recognizes other income from Australian research and development incentives when there is reasonable assurance that the income will be received, the relevant expenditure has been incurred, and the consideration can be reliably measured. The research and development incentive is one of the key elements of the Australian Government’s support for Australia’s innovation system and is supported by legislative law primarily in the form of the Australian Income Tax Assessment Act 1997, as long as eligibility criteria are met. Management has assessed the Company’s research and development activities and expenditures to determine which activities and expenditures are likely to be eligible under the research and development incentive regime described above. At each period end, management estimates the refundable tax offset available to the Company based on available information at the time. Under the program, a percentage of eligible research and development expenses incurred by the Company through its subsidiary in Australia are reimbursed. The percentage was 43.5% for the year ended December 31, 2020 and for the six months ended June 30, 2021. The research and development incentive receivable represents an amount due in connection with the above program. The Company recorded a research and development incentive receivable of $331 and $73 as of June 30, 2021 and December 31, 2020, respectively, in the condensed consolidated balance sheets and other income from Australian research and development incentives of $244 and $30, respectively, for the three months ended June 30, 2021 and 2020, and $315 and $115 for the six months ended June 30, 2021 and 2020, respectively, in the condensed consolidated statements of operations related to refundable research and development incentive program payments in Australia. The following table shows the change in the research and development incentive receivable from January 1, 2020 to June 30, 2021 (in thousands): ​ ​ ​ ​ ​ Balance at January 1, 2020 ​ 185 Australian research and development incentive income, net ​ 231 Cash received for 2019 eligible expenses ​ (331) Foreign currency translation ​ (12) Balance at December 31, 2020 ​ $ 73 Australian research and development incentive income, net ​ ​ 315 Cash received for eligible expenses ​ ​ (66) Foreign currency translation ​ ​ 9 Balance at June 30, 2021 ​ $ 331 ​ Foreign Currency Translation The financial statements of the Company’s Australian subsidiary are measured using the local currency as the functional currency. Assets and liabilities of this subsidiary are translated into U.S. dollars at an exchange rate as of the consolidated balance sheet date. Equity is translated at historical exchange rates. Revenues and expenses are translated into U.S. dollars at average rates of exchange in effect during the period. The resulting cumulative translation adjustments have been recorded as a separate component of stockholders’ equity. Realized and unrealized foreign currency transaction gains and losses are included in the results of operations. Deferred Costs The Company capitalizes certain legal, professional, accounting and other third-party fees that are directly associated with in-process equity financings as deferred costs until such financings are consummated. After consummation of the equity financing, these costs are recorded in stockholders’ equity as a reduction of additional paid-in capital generated as a result of the offering. The Company also capitalizes certain contract acquisition costs. During the six months ended June 30, 2020, the Company incurred contract acquisition costs which were capitalized under ASC 340-40 as incremental costs of obtaining the contract with BeiGene. This cost is amortized on a straight-line basis over the performance period of the research and development services. As of June 30, 2021 and December 31, 2020 there was $68 and $345, respectively, of deferred costs. Deposits As of June 30, 2021 and December 31, 2020, $980 of deposits made by the Company with certain service providers that are to be applied to future payments due under the service agreements or returned to the Company if not utilized were recorded in the condensed consolidated balance sheets. Warrants The Company will recognize on a prospective basis the value of the effect of the down round feature in the 2017 Warrants when it is triggered (i.e., when the exercise price is adjusted downward). This value is measured as the difference between (1) the financial instrument’s fair value (without the down round feature) using the pre-trigger exercise price and (2) the financial instrument’s fair value (with the down round feature) using the reduced exercise price. The value of the effect of the down round feature will be treated as a dividend and a reduction to income available to common stockholders in the basic EPS calculation. In connection with the private placement of common stock completed in January 2020 (the “January 2020 Private Placement”), when the 2017 Warrants were repriced from $1.75 to $1.055 as a result of a down round, the Company recorded a dividend of $303 during the six months ended June 30, 2020. Fair Value of Financial Instruments Certain assets and liabilities are carried at fair value under GAAP. Fair value is defined as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. Valuation techniques used to measure fair value must maximize the use of observable inputs and minimize the use of unobservable inputs. Financial assets and liabilities carried at fair value are to be classified and disclosed in one of the following three levels of the fair value hierarchy, of which the first two are considered observable and the last is considered unobservable: ● Level 1—Quoted prices in active markets for identical assets or liabilities. ● Level 2—Observable inputs (other than Level 1 quoted prices), such as quoted prices in active markets for similar assets or liabilities, quoted prices in markets that are not active for identical or similar assets or liabilities, or other inputs that are observable or can be corroborated by observable market data. ● Level 3—Unobservable inputs that are supported by little or no market activity and that are significant to determining the fair value of the assets or liabilities, including pricing models, discounted cash flow methodologies and similar techniques. During the periods presented, the Company did not change the manner in which it values assets and liabilities that are measured at fair value using Level 3 inputs. There were no transfers within the hierarchy during the six months ended June 30, 2021 or the year ended December 31, 2020. A summary of the assets and liabilities carried at fair value in accordance with the hierarchy defined above is as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total Level 1 Level 2 Level 3 June 30, 2021 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Assets: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Cash equivalents ​ $ 34,758 ​ $ 34,758 ​ $ — ​ $ — Total assets ​ $ 34,758 ​ $ 34,758 ​ $ — ​ $ — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2020 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Assets: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Cash equivalents ​ $ 51,116 ​ $ 51,116 ​ $ — ​ $ — Total assets ​ $ 51,116 ​ $ 51,116 ​ $ — ​ $ — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Liabilities: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Restricted stock liability ​ $ 204 ​ $ — ​ $ 204 ​ $ — Total liabilities ​ $ 204 ​ $ — ​ $ 204 ​ $ — ​ Cash equivalents of $34,758 and $51,116 as of June 30, 2021 and December 31, 2020, respectively, consisted of overnight investments and money market funds and are classified within Level 1 of the fair value hierarchy because they are valued using quoted market prices in active markets. The carrying values of the research and development incentive receivable, accounts payable and accrued liabilities approximate their fair value due to the short-term nature of these assets and liabilities. Leases The Company accounts for leases in accordance with Accounting Standards Codification, or ASC, Topic 842, Leases At the inception of an arrangement, the Company determines whether the arrangement is or contains a lease based on the unique facts and circumstances present. Most leases with a term greater than one year are recognized on the balance sheet as right-of-use assets, lease liabilities and, if applicable, long-term lease liabilities. The Company has elected not to recognize on the balance sheet leases with terms of one year or less. Operating lease liabilities and their corresponding right-of-use assets are recorded based on the present value of lease payments over the expected remaining lease term. The Company has determined that the rate implicit in the lease is not determinable and the Company does not have borrowings with similar terms and collateral. Therefore, the Company considered a variety of factors, including observable debt yields from comparable companies and the volatility in the debt market for securities with similar terms, in determining that 8% was reasonable to use as the incremental borrowing rate for purposes of the calculation of lease liabilities. In accordance with the guidance in Topic 842, components of a lease should be split into three categories: lease components (e.g. land, building, etc.), non-lease components (e.g. common area maintenance, maintenance, consumables, etc.), and non-components (e.g. property taxes, insurance, etc.). Then the fixed and in-substance fixed contract consideration (including any related to non-components) must be allocated based on fair values to the lease components and non-lease components. Although separation of lease and non-lease components is required, certain practical expedients are available. Entities may elect the practical expedient to not separate lease and non-lease components. Rather, they would account for each lease component and the related non-lease component together as a single component. The Company has elected to account for the lease and non-lease components of each of its operating leases as a single lease component and allocate all of the contract consideration to the lease component only. The lease component results in an operating right-of-use asset being recorded on the consolidated balance sheets and amortized such that lease expense is recorded on a straight line basis over the term of the lease. Revenue Recognition The Company records revenue in accordance with ASC Topic 606, Revenue From Contracts with Customers. This standard applies to all contracts with customers, except for contracts that are within the scope of other standards, such as leases, insurance, collaboration arrangements and financial instruments. Under Topic 606, an entity recognizes revenue when its customer obtains control of promised goods or services, in an amount that reflects the consideration that the entity expects to receive in exchange for those goods or services. To determine revenue recognition for arrangements that an entity determines are within the scope of Topic 606, the entity performs the following five steps: (i) identify the contract(s) with a customer; (ii) identify the performance obligations in the contract; (iii) determine the transaction price; (iv) allocate the transaction price to the performance obligations in the contract; and (v) recognize revenue when (or as) the entity satisfies a performance obligation. The Company only applies the five step model to contracts when it is probable that the entity will collect the consideration it is entitled to in exchange for the goods or services it transfers to the customer. At contract inception, once the contract is determined to be within the scope of Topic 606, the Company assesses the goods or services promised within each contract and determines those that are performance obligations, and assesses whether each promised good or service is distinct. The Company then recognizes as revenue the amount of the transaction price that is allocated to the respective performance obligation when (or as) the performance obligation is satisfied. License revenue. Research and Development Services. Customer Options. Milestone Payments. Royalties Collaborative Arrangements The Company analyzes its collaboration arrangements to assess whether such arrangements involve joint operating activities performed by parties that are both active participants in the activities and exposed to significant risks and rewards dependent on the commercial success of such activities and therefore within the scope of ASC Topic 808, Collaborative Arrangements (ASC 808). This assessment is performed throughout the life of the arrangement based on changes in the responsibilities of all parties in the arrangement. For collaboration arrangements within the scope of ASC 808 that contain multiple elements, the Company first determines which elements of the collaboration are deemed to be within the scope of ASC 808 and which elements of the collaboration are more reflective of a vendor-customer relationship and therefore within the scope of ASC 606. For elements of collaboration arrangements that are accounted for pursuant to ASC 808, an appropriate recognition method is determined and applied consistently, generally by analogy to ASC 606. Amounts that are owed to collaboration partners are recognized as an offset to collaboration revenues as such amounts are incurred by the collaboration partner. Where amounts owed to a collaboration partner exceed the Company’s collaboration revenues in each quarterly period, such amounts are classified as research and development expense. Reimbursements from and payments to the customer that are the result of a collaborative relationship with a partner, instead of a customer relationship, such as co-development activities, are recorded as a reduction to research and development expense. For those elements of the arrangement that are accounted for pursuant to ASC 606, the Company applies the five-step model described above under ASC 606. See Note 3 for a complete discussion of the revenue recognition for the Company’s license agreement. Net Loss per Share Basic net loss per share is computed using the weighted average number of common shares outstanding during the period. Diluted net loss per share is computed using the weighted average number of common shares outstanding during the period and, if dilutive, the weighted average number of potential shares of common stock, including the assumed exercise of stock options and warrants. Subsequent Events The Company considers events or transactions that occur after the balance sheet date but prior to the issuance of the financial statements to provide additional evidence for certain estimates or to identify matters that require additional disclosure. Subsequent events have been evaluated as required. Recent Accounting Pronouncements The Company’s significant accounting policies are described in Note 2, “Summary of Significant Accounting Policies”, in the Company’s previously filed Annual Report on Form 10-K for the year ended December 31, 2020.

BeiGene Exclusive Option and Li

BeiGene Exclusive Option and License Agreement	6 Months Ended
	Jun. 30, 2021
BeiGene Exclusive Option and License Agreement
BeiGene Exclusive Option and License Agreement	3. BeiGene Exclusive Option and License Agreement Terms of Agreement On January 3, 2020, the Company entered into an exclusive option and license agreement (the “ BeiGene Agreement”) with BeiGene, Ltd. ( “ BeiGene”) for the clinical development and commercialization of DKN-01, in Asia (excluding Japan), Australia, and New Zealand. The Company retains exclusive rights for the development, manufacturing, and commercialization of DKN-01 for the rest of the world. Pursuant to the BeiGene Agreement, the Company received an upfront cash payment of $3,000 from BeiGene in exchange for granting BeiGene an option to an exclusive license to develop and commercialize DKN-01 in Asia (excluding Japan), Australia, and New Zealand. The Company is eligible to receive up to $132,000 in future option exercise and milestone payments, based upon the achievement of certain development, regulatory, and sales milestones, as well as tiered royalties on any product sales of DKN-01 in the licensed territory. The Company is responsible for conducting development activities prior to the exercise of the option. After the option is exercised, BeiGene is solely responsible for the development and commercialization of DKN-01 in the territory. The BeiGene Agreement continues in effect until the earlier of: (i) 120 days after the end of the option period, if BeiGene has not exercised the option by such date; and (ii) on a country-by country and Licensed Product-by-Licensed Product (as defined in the BeiGene Agreement) basis, the expiration of the Royalty Term (as defined in the BeiGene Agreement) applicable to such licensed product in such country. At any time, BeiGene may terminate the BeiGene Agreement by providing at least 60 days written notice of termination to the Company. Upon termination of the License Agreement, all rights granted by the Company to BeiGene terminate. Revenue Recognition The Company evaluated the BeiGene Agreement to determine whether it is a collaborative arrangement for purposes of ASC 808. The Company concluded that because both parties were active participants and were exposed to the risks and rewards of the BeiGene Agreement, that such activities are under the scope of ASC 808. The Company concluded that BeiGene was a customer with regard to the combined license and research and development activities and as such the contract should be evaluated under ASC 606. In determining the appropriate amount of revenue to be recognized under ASC 606 as the Company fulfills its obligations under the BeiGene Agreement, the Company performs the following steps: (i) identifies the promised goods or services in the contract; (ii) determines whether the promised goods or services are performance obligations including whether they are distinct in the context of the contract; (iii) measures the transaction price, including any constraints on variable consideration; (iv) allocates the transaction price to the performance obligations; and (v) recognizes revenue when (or as) the Company satisfies each performance obligation. ​ The Company identified the following material promises under the BeiGene Agreement: (1) option to an exclusive license to develop and commercialize DKN-01 in Asia (excluding Japan), Australia, and New Zealand, (2) participation in a joint development committee, (3) technology transfer services and (4) pre-option research and development services. The Company determined that the option to an exclusive license in the territory does not represent a material right. Additionally, the Company determined that the participation in the joint development committee, research and development services and technology transfer services are not distinct from each other, as each has limited value without the other. As such, for the purposes of ASC 606, the Company determined that these four material promises, described above, should be combined into a single performance obligation. The Company determined the transaction price is equal to the up-front fee of $3,000 . The transaction price was fully allocated to the single performance obligation and is recognized as revenue on a straight-line basis over the performance period of the research and development services . During each of the three months ended June 30, 2021 and 2020, the Company recognized $375 of license revenue related to the up-front fee received from BeiGene and during each of the six months ended June 30, 2021 and 2020 , the Company recognized $750 of license revenue related to the up-front fee received from BeiGene. Cost of contract acquisition The Company incurred contract acquisition costs of $270 which were capitalized under ASC 340-40 as incremental costs of obtaining the contract with BeiGene. This cost is amortized on a straight-line basis over the performance period of the research and development services. The total amount of amortization expense during the three months ended June 30, 2021 and 2020 was $34 and the total amount of amortization expense during the six months ended June 30, 2021 and 2020 was $68. The closing balance recorded in deferred costs as of June 30, 2021 was $68. Royalties As the license is deemed to be the predominant item to which sales-based royalties relate, the Company will recognize revenue when the related sales occur. No royalty revenue was recognized during the six months ended June 30, 2021 and 2020. The following table presents a summary of the activity in the Company’s contract liabilities, related to the upfront cash payment received of $3,000 , from January 1, 2020 through June 30, 2021 (in thousands): ​ ​ ​ ​ ​ Contract Liabilities: ​ ​ Balance at January 1, 2020 $ — Additions ​ ​ 3,000 Deductions ​ ​ (1,500) Balance at December 31, 2020 ​ $ 1,500 Deductions ​ ​ (750) Balance at June 30, 2021 ​ $ 750 ​

Accrued Expenses

Accrued Expenses	6 Months Ended
	Jun. 30, 2021
Accrued Expenses
Accrued Expenses	4. Accrued Expenses Accrued expenses consist of the following: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ June 30, December 31, ​ 2021 2020 Clinical trials ​ $ 1,370 ​ $ 795 Professional fees ​ 166 ​ 255 Payroll and related expenses ​ 1,073 ​ 1,697 Accrued expenses ​ $ 2,609 ​ $ 2,747 ​

Leases

Leases	6 Months Ended
	Jun. 30, 2021
Leases
Leases	5. Leases The Company has operating leases for real estate in the United States and does not have any finance leases. The Company’s leases may contain options to renew and extend lease terms and options to terminate leases early. Reflected in the right-of-use asset and lease liability on the Company’s consolidated balance sheets are the periods provided by renewal and extension options that the Company is reasonably certain to exercise, as well as the periods provided by termination options that the Company is reasonably certain to not exercise. The Company’s existing lease includes variable lease and non-lease components that are not included in the right-of-use asset and lease liability and are reflected as an expense in the period incurred. Such payments primarily include common area maintenance charges and increases in rent payments that are driven by factors such as future changes in an index (e.g., the Consumer Price Index). In calculating the present value of future lease payments, the Company utilized its incremental borrowing rate based on the remaining lease term at the date of adoption. The Company has elected to account for each lease component and its associated non-lease components as a single lease component and has allocated all of the contract consideration across lease components only. This will potentially result in the initial and subsequent measurement of the balances of the right-of-use asset and lease liability for leases being greater than if the policy election was not applied. The Company has existing net leases in which the non-lease components (e.g. common area maintenance, maintenance, consumables, etc.) are paid separately from rent based on actual costs incurred and therefore are not included in the right-of-use asset and lease liability and are reflected as an expense in the period incurred. As of June 30, 2021, a right-of-use asset of $ 337 and lease liability of $354 are reflected on the condensed consolidated balance sheets. The Company recorded rent expense of $105 and $142 , respectively, during the three months ended June 30, 2021 and 2020, and $210 and $340 , respectively, during the six months ended June 30, 2021 and 2020. Future lease payments under non-cancelable operating leases as of June 30, 2021 are detailed as follows: ​ ​ ​ ​ ​ Future Operating Lease Payments 2021 ​ 219 2022 ​ 146 Total Lease Payments ​ 365 Less: imputed interest ​ (11) Total operating lease liabilities ​ $ 354 ​

Warrants

Warrants	6 Months Ended
	Jun. 30, 2021
Warrants
Warrants	6. Warrants As of June 30, 2021, outstanding warrants to purchase common stock, all of which are classified as equity warrants, consisted of the following: ​ ​ ​ ​ ​ ​ ​ ​ ​ June 30, 2021 ​ ​ Date ​ Number of Shares ​ ​ ​ ​ ​ Exercisable Issuable Exercise Price Expiration Date 1/23/2017 ​ 54,516 ​ $ 0.01 ​ Upon M&A Event 2017 Warrants ​ 2,539,409 ​ $ 1.055 ​ November 2024 2019 Warrants ​ 7,489,893 ​ $ 1.95 ​ February 2026 March 2020 ​ 14,413,902 ​ $ 0.001 ​ March 2027 March 2020 ​ 25,945,035 ​ $ 2.11 ​ March 2027 June 2020 ​ 2,250,000 ​ $ 0.001 ​ June 2027 ​ ​ 52,692,755 ​ ​ ​ ​ ​ ​ 2017 Warrants The 2017 Warrants contain full ratchet anti-dilution protection provisions. The Company will recognize on a prospective basis the value of the effect of the down round feature in the 2017 Warrants when it is triggered (i.e., when the exercise price is adjusted downward). This value is measured as the difference between (1) the financial instrument’s fair value (without the down round feature) using the pre-trigger exercise price and (2) the financial instrument’s fair value (with the down round feature) using the reduced exercise price. The value of the effect of the down round feature will be treated as a dividend and a reduction to income available to common stockholders in the basic EPS calculation. In connection with the January 2020 Private Placement, when the 2017 Warrants were repriced from $1.75 to $1.055, the Company recorded a dividend of $303 during the six months ended June 30, 2020. 2019 Warrants On February 5, 2019, in connection with the 2019 Public Offering, the Company issued immediately exercisable warrants (the “2019 Warrants”) to purchase 7,557,142 shares of common stock to investors. The 2019 Warrants have an exercise price of $1.95 per share and expire on February 5, 2026. The 2019 Warrants qualify for equity classification. March 2020 Warrants On January 3, 2020, the Company entered into a Securities Purchase Agreement with investors, providing for a private placement transaction exempt from the Securities Act of 1933, as amended, pursuant to which the Company issued and sold 1,421,801 shares of its Series A Preferred Stock, at a purchase price of $10.54 per share, and 1,137,442 shares of its Series B Preferred Stock at a purchase price of $10.55 per share, and one (1) share of the Company’s Special Voting Stock entitling the purchaser of Series A Preferred Stock to elect one member of the Company’s board of directors. On March 5, 2020, the Company’s stockholders approved the conversion of the Series A Preferred Stock into a pre-funded warrant to purchase 14,413,902 shares of common stock at an exercise price of $0.001 (the “March 2020 Pre-funded Warrants”) and the conversion of the Series B Preferred Stock into 11,531,133 shares of common stock. Each investor also received a warrant to purchase an equal number of shares of common stock at an exercise price of $2.11 per share (the “Coverage Warrants”). The March 2020 Pre-funded Warrants and the Coverage Warrants expire on March 5, 2027 and qualify for equity classification. June 2020 Warrants On June 22, 2020, the Company completed a public offering (“the 2020 Public Offering”) whereby the Company issued 20,250,000 shares of its common stock, at $2.00 per share and, in lieu of common stock, offered pre-funded warrants (the “June 2020 Pre-funded Warrants”) to purchase up to 2,250,000 shares of its common stock to certain investors. The June 2020 Pre-funded Warrants have an exercise price of $0.001 per share, expire on June 22, 2027 and qualify for equity classification.

Common Stock

Common Stock	6 Months Ended
	Jun. 30, 2021
Common Stock
Common Stock	7. Common Stock Each share of common stock entitles the holder to one vote on all matters submitted to a vote of the Company’s stockholders. Common stockholders are entitled to receive dividends, as may be declared by the board of directors, if any, subject to the preferential dividend rights of the preferred stockholders. Through June 30, 2021, no dividends have been declared for shares of common stock. January 2020 Private Placement On January 3, 2020, the Company issued and sold 1,421,801 shares of its Series A Preferred Stock at a purchase price of $10.54 per share, and 1,137,442 shares of its Series B Preferred Stock at a purchase price of $10.55 per share, and one (1) share of its Special Voting Stock, entitling the purchaser of Series A Preferred Stock to elect one member of the Company’s board of directors, for aggregate net proceeds to the Company of approximately $25,322. On March 5, 2020, the Company’s stockholders approved the conversion of the Series A Preferred Stock into a pre-funded warrant to purchase 14,413,902 shares of common stock at an exercise price of $0.001 per share and the conversion of the Series B Preferred Stock into 11,531,133 shares of its common stock, par value $0.001 per share. Each investor also received the Coverage Warrants to purchase an equal number of shares at an exercise price of $2.11 per share. In connection with the January 2020 Private Placement, Series A Preferred Stock holders and Series B Preferred Stock holders were entitled to cash dividends at a fixed cumulative percentage of 8% per annum plus any dividends declared on outstanding common stock on an as-converted basis, effective on the issuance date of the Series A Preferred Stock and Series B Preferred Stock. The cash dividends were converted to shares of common stock upon the conversion of the Series A Preferred Stock to pre-funded warrants and Series B Preferred Stock to common stock. During the six months ended June 30, 2020, the Company recorded $372 of Series A Preferred Stock and Series B Preferred Stock dividends, which qualify as cumulative dividends, and in the calculation of EPS are subtracted from net income in arriving at income attributable to common stockholders. The Company determined that the embedded conversion features of the Series A Preferred Stock and Series B Preferred Stock to receive the Coverage Warrants each met the definition of a contingent beneficial conversion feature and should be accounted for separately as a derivative. The recognition of the beneficial conversion feature occurred upon the conversion of the Series A Preferred Stock into pre-funded warrants and Series B Preferred Stock into common stock and the issuance of the Coverage Warrants. The Company measured the contingent beneficial conversion features’ intrinsic values on January 3, 2020 and determined that the beneficial conversion features were valued at $5,226 for Series A and $4,173 for Series B, respectively. Upon conversion, the discount originated by the contingent beneficial conversion feature, at its intrinsic value for Series A Preferred Stock and Series B Preferred Stock, was immediately recognized as a dividend. The dividend is reflected as an adjustment to basic and diluted net loss per share attributable to common stockholders. Public Offering of Common Stock – June 2020 On June 22, 2020, the Company completed the 2020 Public Offering, whereby the Company issued 20,250,000 shares of its common stock at $2.00 per share and, in lieu of common stock, issued certain investors 2,250,000 of its June 2020 Pre-funded Warrants. The June 2020 Pre-funded Warrants have an exercise price of $0.001 per share, expire on June 22, 2027 and qualify for equity classification. On June 25, 2020, the underwriters exercised their right to purchase 3,375,000 additional shares of the Company’s common stock at the public offering price per share of common stock, less underwriting discounts and commissions. The aggregate net proceeds received by the Company from the 2020 Public Offering were approximately $48,276, net of underwriting discounts and commissions and estimated offering expenses payable by the Company.

Equity Incentive Plans

Equity Incentive Plans	6 Months Ended
	Jun. 30, 2021
Equity Incentive Plans
Equity Incentive Plans	8. Equity Incentive Plans Equity Incentive Plans In September 2012, the Company adopted the 2012 Equity Incentive Plan, as amended, which provides designated employees of the Company and its affiliates, certain consultants and advisors who perform services for the Company and its affiliates, and nonemployee members of the board of directors of the Company and its affiliates with the opportunity to receive grants of incentive stock options, nonqualified stock options and stock awards. On January 20, 2017, the Company’s stockholders approved the 2016 Equity Incentive Plan (the “2016 Plan”). Beginning on January 1, 2018, the number of shares of common stock authorized for issuance pursuant to the 2016 Plan was increased each January 1 by an amount equal to four percent (4%) of the Company’s outstanding common stock as of the end of the immediately preceding calendar year or such other amount as determined by the compensation committee of the Company’s board of directors. As of June 30, 2021, there were 456,879 shares available for grant under the Company’s equity incentive plans. A summary of stock option activity under the Equity Plans is as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted ​ ​ ​ ​ ​ ​ Average Weighted ​ Aggregate ​ ​ ​ Exercise Price Average Remaining ​ Intrinsic ​ Options Per Share Life in Years ​ Value Outstanding at December 31, 2020 6,393,853 ​ $ 5.29 7.96 $ 1,961 Granted ​ 2,336,500 ​ $ 2.21 ​ ​ ​ ​ ​ Exercised ​ (2,292) ​ $ 1.55 ​ ​ ​ ​ ​ Forfeited (341,926) ​ $ 3.19 ​ ​ ​ ​ Outstanding at June 30, 2021 8,386,135 ​ $ 4.52 8.04 ​ $ 402 Options exercisable at June 30, 2021 4,305,584 ​ $ 6.74 6.99 ​ $ 231 Options vested and expected to vest at June 30, 2021 8,386,135 ​ $ 4.52 8.04 ​ $ 402 ​ The grant date fair value of the options granted during the six months ended June 30, 2021 and 2020 was estimated at the date of grant using the Black-Scholes option valuation model. The expected life was estimated using the “simplified” method as defined by the SEC’s Staff Accounting Bulletin 107, Share-Based Payment. The expected volatility was based on the historical volatility of comparable public companies from a representative peer group selected based on industry and market capitalization data. The risk-free interest rate was based on the continuous rates provided by the U.S. Treasury with a term approximating the expected life of the option. The expected dividend yield was 0% because the Company does not expect to pay any dividends for the foreseeable future. The Company elected the straight-line attribution method in recognizing the grant date fair value of options issued over the requisite service periods of the awards, which are generally the vesting periods. The weighted average grant date fair value for the stock options granted during the six months ended June 30, 2021 and 2020 was $2.21 and $2.18 per share, respectively. ​ The assumptions that the Company used to determine the grant-date fair value of stock options granted to employees and directors during the six months ended June 30, 2021 and 2020 were as follows, presented on a weighted average basis: ​ ​ ​ ​ ​ ​ ​ ​ ​ Six Months ​ Six Months ​ ​ ​ Ended June 30, ​ Ended June 30, ​ ​ 2021 2020 ​ ​ ​ ​ ​ ​ ​ Expected volatility ​ 66.94 % 66.94 % Weighted average risk-free interest rate ​ 0.80 % 0.79 % Expected dividend yield ​ 0.00 % 0.00 % Expected term (in years) ​ 6.86 ​ 6.84 ​ ​ Stock options generally vest over a three The Company recognized stock-based compensation expense related to the issuance of stock option awards to employees and non-employees in the condensed consolidated statements of operations as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended June 30, ​ Six Months Ended June 30, ​ 2021 2020 2021 2020 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Research and development $ 377 ​ $ 249 ​ $ 707 ​ $ 438 General and administrative ​ 399 ​ 290 ​ ​ 783 ​ 658 Total ​ $ 776 ​ $ 539 ​ $ 1,490 ​ $ 1,096 ​ Restricted Stock Units During the year ended December 31, 2020, the Company issued 92,500 restricted stock units (“RSUs”) to employees under the 2016 Plan. Upon vesting of the RSUs, the Company has the option to settle the award by either issuing shares of the Company’s common stock or paying an amount of cash equal to the fair value of the Company’s common stock on the settlement date. In January 2021, the Company cash settled 92,500 RSUs. As of December 31, 2020, these RSUs are classified as restricted stock liability in the condensed consolidated balance sheets of $204, as they contain a cash settlement option. During the six months ended June 30, 2021 and 2020, the Company granted 275,000 and 660,606, respectively, RSUs to executive officers that will cliff vest and will be settled after three years of continuous service, or upon a change of control of the Company, whichever is earlier, pursuant to the 2016 Plan. During the three months ended June 30, 2021 and 2020, the Company recognized $136 and $78, respectively, and during the six months ended June 30, 2021 and 2020, the Company recognized $255 and $91, respectively, of stock based compensation expense related to equity classified RSUs, as they do not contain a cash settlement option. The following table presents a summary of outstanding RSUs under the 2016 Plan as of June 30, 2021: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted ​ ​ ​ ​ Average Grant ​ Number of Shares Date Fair Value Outstanding at December 31, 2020 753,106 ​ $ 1.52 Awarded 275,000 ​ $ 2.57 Settled in cash (92,500) ​ $ 1.97 Outstanding at June 30, 2021 935,606 ​ $ 1.76 ​ As of June 30, 2021, there were 935,606 shares outstanding covered by RSUs that are expected to vest and the weighted average grant date fair value of these shares of restricted stock was $1.76 per share and the aggregate grant date fair value of these shares of restricted stock was approximately $1,645. As of June 30, 2021, there was approximately $1,141 of unrecognized compensation costs related to RSUs granted to employees, which are expected to be recognized as expense over a remaining weighted average period of 2.17 years.

Net Loss Per Share

Net Loss Per Share	6 Months Ended
	Jun. 30, 2021
Net Loss Per Share
Net Loss Per Share	9. Net Loss Per Share Basic and diluted net loss per share for the three and six months ended June 30, 2021 and 2020 was calculated as follows (in thousands except share and per share amounts). ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended June 30, ​ Six Months Ended June 30, ​ 2021 2020 2021 2020 Numerator: ​ ​ ​ ​ ​ ​ ​ Net loss ​ $ (9,526) ​ $ (6,516) ​ $ (18,660) ​ $ (13,747) Dividend attributable to down round feature of warrants ​ — ​ — ​ — ​ (303) Dividend attributable to Series A & B convertible preferred stock ​ ​ — ​ ​ — ​ ​ — ​ ​ (372) Series A & B convertible preferred stock - beneficial conversion feature ​ ​ — ​ ​ — ​ ​ — ​ ​ (9,399) Net loss attributable to common stockholders for basic and diluted loss per share ​ $ (9,526) ​ $ (6,516) ​ $ (18,660) ​ $ (23,821) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Denominator: ​ ​ ​ ​ ​ ​ ​ ​ Weighted average number of common shares outstanding – basic and diluted ​ 76,389,525 ​ 52,442,597 ​ 76,384,077 ​ 42,037,405 Net loss per share attributable to common stockholders – basic and diluted ​ $ (0.12) ​ $ (0.12) ​ $ (0.24) ​ $ (0.57) ​ Included within weighted average common shares outstanding are 16,718,418 common shares issuable upon the exercise of the pre-funded warrants as the warrants are exercisable at any time for nominal consideration, and as such, the shares are considered outstanding for the purpose of calculating basic and diluted net loss per share attributable to common stockholders. The Company’s potentially dilutive securities include RSUs, stock options and warrants. These securities were excluded from the computations of diluted net loss per share for the three and six months ended June 30, 2021 and 2020, as the effect would be to reduce the net loss per share. The following table includes the potential shares of common stock, presented based on amounts outstanding at each period end, that were excluded from the computation of diluted net loss per share attributable to common stockholders for the periods indicated because including them would have had an anti-dilutive effect: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended June 30, ​ Six Months Ended June 30, ​ 2021 2020 2021 2020 Restricted stock units to purchase common stock ​ 935,606 ​ 660,606 ​ 935,606 ​ 660,606 Options to purchase common stock 8,386,135 5,481,631 ​ 8,386,135 5,481,631 Warrants to purchase common stock ​ 35,974,337 ​ 36,040,833 ​ 35,974,337 ​ 36,040,833 ​ 45,296,078 42,183,070 ​ 45,296,078 42,183,070 ​

Commitments and Contingencies

Commitments and Contingencies	6 Months Ended
	Jun. 30, 2021
Commitments and Contingencies
Commitments and Contingencies	10. Commitments and Contingencies Manufacturing Agreements License and Service Agreement License Agreement Legal Proceedings In 2016, a patent covering the use of the TRX518 antibody in combination with a chemotherapeutic agent for treating cancer was granted to the Company by the EPO. In March 2017, notices of opposition to this patent were filed at the European Patent Office (EPO) by ten different entities, including several major pharmaceutical companies. Oral proceedings at the EPO took place on December 4 and 5, 2018. At the conclusion of the oral proceedings, the Opposition Division decided that the patent should be revoked in its entirety on the ground that the claims as granted contained added matter. Subsequently, the Opposition Division issued an interlocutory decision restating its conclusion that the claims as granted contained added matter and revoking the patent. The Company has filed an appeal of the decision of the Opposition Division seeking to obtain a reversal of the Opposition Division’s decision on added matter. The EPO Board of Appeal has not yet scheduled the appeal hearing. In December of 2019, a patent covering the use of the TRX518 antibody in combination with the chemotherapeutic agent, gemcitabine, for treating a colon tumor or adenocarcinoma of the colon, was granted to the Company by the EPO. A Notice of Opposition was filed against the patent by a single opponent, Sanofi, on September 25, 2020. The EPO issued a Communication on October 9, 2020 setting a deadline of February 9, 2021 for the Patentee to file a response to the Notice of Opposition. The Company filed a timely reply to the opponent’s Notice of Opposition on February 9, 2021. Oral Indemnification Agreements

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	6 Months Ended
	Jun. 30, 2021
Summary of Significant Accounting Policies
Principles of Consolidation	Principles of Consolidation The accompanying condensed consolidated financial statements include the accounts of the Company and its wholly owned subsidiaries. All intercompany accounts and transactions are eliminated upon consolidation.
Use of Estimates	Use of Estimates The presentation of condensed consolidated 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 condensed consolidated financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates.
Research and development incentive income and receivable	Research and development incentive income and receivable The Company recognizes other income from Australian research and development incentives when there is reasonable assurance that the income will be received, the relevant expenditure has been incurred, and the consideration can be reliably measured. The research and development incentive is one of the key elements of the Australian Government’s support for Australia’s innovation system and is supported by legislative law primarily in the form of the Australian Income Tax Assessment Act 1997, as long as eligibility criteria are met. Management has assessed the Company’s research and development activities and expenditures to determine which activities and expenditures are likely to be eligible under the research and development incentive regime described above. At each period end, management estimates the refundable tax offset available to the Company based on available information at the time. Under the program, a percentage of eligible research and development expenses incurred by the Company through its subsidiary in Australia are reimbursed. The percentage was 43.5% for the year ended December 31, 2020 and for the six months ended June 30, 2021. The research and development incentive receivable represents an amount due in connection with the above program. The Company recorded a research and development incentive receivable of $331 and $73 as of June 30, 2021 and December 31, 2020, respectively, in the condensed consolidated balance sheets and other income from Australian research and development incentives of $244 and $30, respectively, for the three months ended June 30, 2021 and 2020, and $315 and $115 for the six months ended June 30, 2021 and 2020, respectively, in the condensed consolidated statements of operations related to refundable research and development incentive program payments in Australia. The following table shows the change in the research and development incentive receivable from January 1, 2020 to June 30, 2021 (in thousands): ​ ​ ​ ​ ​ Balance at January 1, 2020 ​ 185 Australian research and development incentive income, net ​ 231 Cash received for 2019 eligible expenses ​ (331) Foreign currency translation ​ (12) Balance at December 31, 2020 ​ $ 73 Australian research and development incentive income, net ​ ​ 315 Cash received for eligible expenses ​ ​ (66) Foreign currency translation ​ ​ 9 Balance at June 30, 2021 ​ $ 331
Foreign Currency Translation	Foreign Currency Translation The financial statements of the Company’s Australian subsidiary are measured using the local currency as the functional currency. Assets and liabilities of this subsidiary are translated into U.S. dollars at an exchange rate as of the consolidated balance sheet date. Equity is translated at historical exchange rates. Revenues and expenses are translated into U.S. dollars at average rates of exchange in effect during the period. The resulting cumulative translation adjustments have been recorded as a separate component of stockholders’ equity. Realized and unrealized foreign currency transaction gains and losses are included in the results of operations.
Deferred Costs	Deferred Costs The Company capitalizes certain legal, professional, accounting and other third-party fees that are directly associated with in-process equity financings as deferred costs until such financings are consummated. After consummation of the equity financing, these costs are recorded in stockholders’ equity as a reduction of additional paid-in capital generated as a result of the offering. The Company also capitalizes certain contract acquisition costs. During the six months ended June 30, 2020, the Company incurred contract acquisition costs which were capitalized under ASC 340-40 as incremental costs of obtaining the contract with BeiGene. This cost is amortized on a straight-line basis over the performance period of the research and development services. As of June 30, 2021 and December 31, 2020 there was $68 and $345, respectively, of deferred costs.
Deposits	Deposits As of June 30, 2021 and December 31, 2020, $980 of deposits made by the Company with certain service providers that are to be applied to future payments due under the service agreements or returned to the Company if not utilized were recorded in the condensed consolidated balance sheets.
Warrants	Warrants The Company will recognize on a prospective basis the value of the effect of the down round feature in the 2017 Warrants when it is triggered (i.e., when the exercise price is adjusted downward). This value is measured as the difference between (1) the financial instrument’s fair value (without the down round feature) using the pre-trigger exercise price and (2) the financial instrument’s fair value (with the down round feature) using the reduced exercise price. The value of the effect of the down round feature will be treated as a dividend and a reduction to income available to common stockholders in the basic EPS calculation. In connection with the private placement of common stock completed in January 2020 (the “January 2020 Private Placement”), when the 2017 Warrants were repriced from $1.75 to $1.055 as a result of a down round, the Company recorded a dividend of $303 during the six months ended June 30, 2020.
Fair Value of Financial Instruments	Fair Value of Financial Instruments Certain assets and liabilities are carried at fair value under GAAP. Fair value is defined as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. Valuation techniques used to measure fair value must maximize the use of observable inputs and minimize the use of unobservable inputs. Financial assets and liabilities carried at fair value are to be classified and disclosed in one of the following three levels of the fair value hierarchy, of which the first two are considered observable and the last is considered unobservable: ● Level 1—Quoted prices in active markets for identical assets or liabilities. ● Level 2—Observable inputs (other than Level 1 quoted prices), such as quoted prices in active markets for similar assets or liabilities, quoted prices in markets that are not active for identical or similar assets or liabilities, or other inputs that are observable or can be corroborated by observable market data. ● Level 3—Unobservable inputs that are supported by little or no market activity and that are significant to determining the fair value of the assets or liabilities, including pricing models, discounted cash flow methodologies and similar techniques. During the periods presented, the Company did not change the manner in which it values assets and liabilities that are measured at fair value using Level 3 inputs. There were no transfers within the hierarchy during the six months ended June 30, 2021 or the year ended December 31, 2020. A summary of the assets and liabilities carried at fair value in accordance with the hierarchy defined above is as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total Level 1 Level 2 Level 3 June 30, 2021 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Assets: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Cash equivalents ​ $ 34,758 ​ $ 34,758 ​ $ — ​ $ — Total assets ​ $ 34,758 ​ $ 34,758 ​ $ — ​ $ — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2020 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Assets: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Cash equivalents ​ $ 51,116 ​ $ 51,116 ​ $ — ​ $ — Total assets ​ $ 51,116 ​ $ 51,116 ​ $ — ​ $ — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Liabilities: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Restricted stock liability ​ $ 204 ​ $ — ​ $ 204 ​ $ — Total liabilities ​ $ 204 ​ $ — ​ $ 204 ​ $ — ​ Cash equivalents of $34,758 and $51,116 as of June 30, 2021 and December 31, 2020, respectively, consisted of overnight investments and money market funds and are classified within Level 1 of the fair value hierarchy because they are valued using quoted market prices in active markets. The carrying values of the research and development incentive receivable, accounts payable and accrued liabilities approximate their fair value due to the short-term nature of these assets and liabilities.
Leases	Leases The Company accounts for leases in accordance with Accounting Standards Codification, or ASC, Topic 842, Leases At the inception of an arrangement, the Company determines whether the arrangement is or contains a lease based on the unique facts and circumstances present. Most leases with a term greater than one year are recognized on the balance sheet as right-of-use assets, lease liabilities and, if applicable, long-term lease liabilities. The Company has elected not to recognize on the balance sheet leases with terms of one year or less. Operating lease liabilities and their corresponding right-of-use assets are recorded based on the present value of lease payments over the expected remaining lease term. The Company has determined that the rate implicit in the lease is not determinable and the Company does not have borrowings with similar terms and collateral. Therefore, the Company considered a variety of factors, including observable debt yields from comparable companies and the volatility in the debt market for securities with similar terms, in determining that 8% was reasonable to use as the incremental borrowing rate for purposes of the calculation of lease liabilities. In accordance with the guidance in Topic 842, components of a lease should be split into three categories: lease components (e.g. land, building, etc.), non-lease components (e.g. common area maintenance, maintenance, consumables, etc.), and non-components (e.g. property taxes, insurance, etc.). Then the fixed and in-substance fixed contract consideration (including any related to non-components) must be allocated based on fair values to the lease components and non-lease components. Although separation of lease and non-lease components is required, certain practical expedients are available. Entities may elect the practical expedient to not separate lease and non-lease components. Rather, they would account for each lease component and the related non-lease component together as a single component. The Company has elected to account for the lease and non-lease components of each of its operating leases as a single lease component and allocate all of the contract consideration to the lease component only. The lease component results in an operating right-of-use asset being recorded on the consolidated balance sheets and amortized such that lease expense is recorded on a straight line basis over the term of the lease.
Revenue Recognition	Revenue Recognition The Company records revenue in accordance with ASC Topic 606, Revenue From Contracts with Customers. This standard applies to all contracts with customers, except for contracts that are within the scope of other standards, such as leases, insurance, collaboration arrangements and financial instruments. Under Topic 606, an entity recognizes revenue when its customer obtains control of promised goods or services, in an amount that reflects the consideration that the entity expects to receive in exchange for those goods or services. To determine revenue recognition for arrangements that an entity determines are within the scope of Topic 606, the entity performs the following five steps: (i) identify the contract(s) with a customer; (ii) identify the performance obligations in the contract; (iii) determine the transaction price; (iv) allocate the transaction price to the performance obligations in the contract; and (v) recognize revenue when (or as) the entity satisfies a performance obligation. The Company only applies the five step model to contracts when it is probable that the entity will collect the consideration it is entitled to in exchange for the goods or services it transfers to the customer. At contract inception, once the contract is determined to be within the scope of Topic 606, the Company assesses the goods or services promised within each contract and determines those that are performance obligations, and assesses whether each promised good or service is distinct. The Company then recognizes as revenue the amount of the transaction price that is allocated to the respective performance obligation when (or as) the performance obligation is satisfied.
License revenue	License revenue.
Research and Development Services	Research and Development Services.
Customer Options	Customer Options.
Milestone Payments	Milestone Payments.
Royalties	Royalties
Collaborative Arrangements	Collaborative Arrangements The Company analyzes its collaboration arrangements to assess whether such arrangements involve joint operating activities performed by parties that are both active participants in the activities and exposed to significant risks and rewards dependent on the commercial success of such activities and therefore within the scope of ASC Topic 808, Collaborative Arrangements (ASC 808). This assessment is performed throughout the life of the arrangement based on changes in the responsibilities of all parties in the arrangement. For collaboration arrangements within the scope of ASC 808 that contain multiple elements, the Company first determines which elements of the collaboration are deemed to be within the scope of ASC 808 and which elements of the collaboration are more reflective of a vendor-customer relationship and therefore within the scope of ASC 606. For elements of collaboration arrangements that are accounted for pursuant to ASC 808, an appropriate recognition method is determined and applied consistently, generally by analogy to ASC 606. Amounts that are owed to collaboration partners are recognized as an offset to collaboration revenues as such amounts are incurred by the collaboration partner. Where amounts owed to a collaboration partner exceed the Company’s collaboration revenues in each quarterly period, such amounts are classified as research and development expense. Reimbursements from and payments to the customer that are the result of a collaborative relationship with a partner, instead of a customer relationship, such as co-development activities, are recorded as a reduction to research and development expense. For those elements of the arrangement that are accounted for pursuant to ASC 606, the Company applies the five-step model described above under ASC 606. See Note 3 for a complete discussion of the revenue recognition for the Company’s license agreement.
Net Loss per Share	Net Loss per Share Basic net loss per share is computed using the weighted average number of common shares outstanding during the period. Diluted net loss per share is computed using the weighted average number of common shares outstanding during the period and, if dilutive, the weighted average number of potential shares of common stock, including the assumed exercise of stock options and warrants.
Subsequent Events	Subsequent Events The Company considers events or transactions that occur after the balance sheet date but prior to the issuance of the financial statements to provide additional evidence for certain estimates or to identify matters that require additional disclosure. Subsequent events have been evaluated as required.
Recent Accounting Pronouncements	Recent Accounting Pronouncements The Company’s significant accounting policies are described in Note 2, “Summary of Significant Accounting Policies”, in the Company’s previously filed Annual Report on Form 10-K for the year ended December 31, 2020.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	6 Months Ended
	Jun. 30, 2021
Summary of Significant Accounting Policies
Schedule of change in the research and development incentive receivable	The following table shows the change in the research and development incentive receivable from January 1, 2020 to June 30, 2021 (in thousands): ​ ​ ​ ​ ​ Balance at January 1, 2020 ​ 185 Australian research and development incentive income, net ​ 231 Cash received for 2019 eligible expenses ​ (331) Foreign currency translation ​ (12) Balance at December 31, 2020 ​ $ 73 Australian research and development incentive income, net ​ ​ 315 Cash received for eligible expenses ​ ​ (66) Foreign currency translation ​ ​ 9 Balance at June 30, 2021 ​ $ 331
Summary of assets and liabilities carried at fair value in accordance with the hierarchy	A summary of the assets and liabilities carried at fair value in accordance with the hierarchy defined above is as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total Level 1 Level 2 Level 3 June 30, 2021 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Assets: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Cash equivalents ​ $ 34,758 ​ $ 34,758 ​ $ — ​ $ — Total assets ​ $ 34,758 ​ $ 34,758 ​ $ — ​ $ — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2020 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Assets: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Cash equivalents ​ $ 51,116 ​ $ 51,116 ​ $ — ​ $ — Total assets ​ $ 51,116 ​ $ 51,116 ​ $ — ​ $ — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Liabilities: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Restricted stock liability ​ $ 204 ​ $ — ​ $ 204 ​ $ — Total liabilities ​ $ 204 ​ $ — ​ $ 204 ​ $ —

BeiGene Exclusive Option and _2

BeiGene Exclusive Option and License Agreement (Tables)	6 Months Ended
	Jun. 30, 2021
BeiGene Exclusive Option and License Agreement
Summary of activity in Company's contract liabilities	The following table presents a summary of the activity in the Company’s contract liabilities, related to the upfront cash payment received of $3,000 , from January 1, 2020 through June 30, 2021 (in thousands): ​ ​ ​ ​ ​ Contract Liabilities: ​ ​ Balance at January 1, 2020 $ — Additions ​ ​ 3,000 Deductions ​ ​ (1,500) Balance at December 31, 2020 ​ $ 1,500 Deductions ​ ​ (750) Balance at June 30, 2021 ​ $ 750

Accrued Expenses (Tables)

Accrued Expenses (Tables)	6 Months Ended
	Jun. 30, 2021
Accrued Expenses
Schedule of accrued expenses	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ June 30, December 31, ​ 2021 2020 Clinical trials ​ $ 1,370 ​ $ 795 Professional fees ​ 166 ​ 255 Payroll and related expenses ​ 1,073 ​ 1,697 Accrued expenses ​ $ 2,609 ​ $ 2,747

Leases (Tables)

Leases (Tables)	6 Months Ended
	Jun. 30, 2021
Leases
Schedule of future lease payments	​ ​ ​ ​ ​ Future Operating Lease Payments 2021 ​ 219 2022 ​ 146 Total Lease Payments ​ 365 Less: imputed interest ​ (11) Total operating lease liabilities ​ $ 354

Warrants (Tables)

Warrants (Tables)	6 Months Ended
	Jun. 30, 2021
Warrants
Schedule of warrants	​ ​ ​ ​ ​ ​ ​ ​ ​ June 30, 2021 ​ ​ Date ​ Number of Shares ​ ​ ​ ​ ​ Exercisable Issuable Exercise Price Expiration Date 1/23/2017 ​ 54,516 ​ $ 0.01 ​ Upon M&A Event 2017 Warrants ​ 2,539,409 ​ $ 1.055 ​ November 2024 2019 Warrants ​ 7,489,893 ​ $ 1.95 ​ February 2026 March 2020 ​ 14,413,902 ​ $ 0.001 ​ March 2027 March 2020 ​ 25,945,035 ​ $ 2.11 ​ March 2027 June 2020 ​ 2,250,000 ​ $ 0.001 ​ June 2027 ​ ​ 52,692,755 ​ ​ ​ ​ ​

Equity Incentive Plans (Tables)

Equity Incentive Plans (Tables)	6 Months Ended
	Jun. 30, 2021
Equity Incentive Plans
Summary of stock option activity under the Equity Plans	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted ​ ​ ​ ​ ​ ​ Average Weighted ​ Aggregate ​ ​ ​ Exercise Price Average Remaining ​ Intrinsic ​ Options Per Share Life in Years ​ Value Outstanding at December 31, 2020 6,393,853 ​ $ 5.29 7.96 $ 1,961 Granted ​ 2,336,500 ​ $ 2.21 ​ ​ ​ ​ ​ Exercised ​ (2,292) ​ $ 1.55 ​ ​ ​ ​ ​ Forfeited (341,926) ​ $ 3.19 ​ ​ ​ ​ Outstanding at June 30, 2021 8,386,135 ​ $ 4.52 8.04 ​ $ 402 Options exercisable at June 30, 2021 4,305,584 ​ $ 6.74 6.99 ​ $ 231 Options vested and expected to vest at June 30, 2021 8,386,135 ​ $ 4.52 8.04 ​ $ 402
Schedule of assumptions used to determine grant-date fair value of stock options	​ ​ ​ ​ ​ ​ ​ ​ ​ Six Months ​ Six Months ​ ​ ​ Ended June 30, ​ Ended June 30, ​ ​ 2021 2020 ​ ​ ​ ​ ​ ​ ​ Expected volatility ​ 66.94 % 66.94 % Weighted average risk-free interest rate ​ 0.80 % 0.79 % Expected dividend yield ​ 0.00 % 0.00 % Expected term (in years) ​ 6.86 ​ 6.84 ​
Schedule of stock-based compensation expense related to issuance of stock option awards recognized in condensed consolidated statements of operations	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended June 30, ​ Six Months Ended June 30, ​ 2021 2020 2021 2020 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Research and development $ 377 ​ $ 249 ​ $ 707 ​ $ 438 General and administrative ​ 399 ​ 290 ​ ​ 783 ​ 658 Total ​ $ 776 ​ $ 539 ​ $ 1,490 ​ $ 1,096
Summary of outstanding RSU under the 2016 Plan	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted ​ ​ ​ ​ Average Grant ​ Number of Shares Date Fair Value Outstanding at December 31, 2020 753,106 ​ $ 1.52 Awarded 275,000 ​ $ 2.57 Settled in cash (92,500) ​ $ 1.97 Outstanding at June 30, 2021 935,606 ​ $ 1.76

Net Loss Per Share (Tables)

Net Loss Per Share (Tables)	6 Months Ended
	Jun. 30, 2021
Net Loss Per Share
Schedule of basic and diluted net loss per share	Basic and diluted net loss per share for the three and six months ended June 30, 2021 and 2020 was calculated as follows (in thousands except share and per share amounts). ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended June 30, ​ Six Months Ended June 30, ​ 2021 2020 2021 2020 Numerator: ​ ​ ​ ​ ​ ​ ​ Net loss ​ $ (9,526) ​ $ (6,516) ​ $ (18,660) ​ $ (13,747) Dividend attributable to down round feature of warrants ​ — ​ — ​ — ​ (303) Dividend attributable to Series A & B convertible preferred stock ​ ​ — ​ ​ — ​ ​ — ​ ​ (372) Series A & B convertible preferred stock - beneficial conversion feature ​ ​ — ​ ​ — ​ ​ — ​ ​ (9,399) Net loss attributable to common stockholders for basic and diluted loss per share ​ $ (9,526) ​ $ (6,516) ​ $ (18,660) ​ $ (23,821) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Denominator: ​ ​ ​ ​ ​ ​ ​ ​ Weighted average number of common shares outstanding – basic and diluted ​ 76,389,525 ​ 52,442,597 ​ 76,384,077 ​ 42,037,405 Net loss per share attributable to common stockholders – basic and diluted ​ $ (0.12) ​ $ (0.12) ​ $ (0.24) ​ $ (0.57) ​
Schedule of potentially anti-dilutive securities excluded from calculation of diluted net loss per share	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended June 30, ​ Six Months Ended June 30, ​ 2021 2020 2021 2020 Restricted stock units to purchase common stock ​ 935,606 ​ 660,606 ​ 935,606 ​ 660,606 Options to purchase common stock 8,386,135 5,481,631 ​ 8,386,135 5,481,631 Warrants to purchase common stock ​ 35,974,337 ​ 36,040,833 ​ 35,974,337 ​ 36,040,833 ​ 45,296,078 42,183,070 ​ 45,296,078 42,183,070

Nature of Business, Basis of _2

Nature of Business, Basis of Presentation and Liquidity - Liquidity (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Liquidity
Cash and cash equivalents	$ 35,734		$ 35,734		$ 52,071
Accumulated deficit	241,645		241,645		$ 222,985
Net loss	$ 9,526	$ 6,516	$ 18,660	$ 13,747

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Significant Accounting Policies (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020	Mar. 05, 2020	Jan. 31, 2020
Research and development incentive income and receivable
Research and development expenses reimbursed (as a percent)			43.50%		43.50%
Research and development incentive income and receivable
Balance at the beginning of the period			$ 73	$ 185	$ 185
Australian research and development incentive income, net	$ 244	$ 30	315	115	231
Cash received for eligible expenses			(66)		(331)
Foreign currency translation			9		(12)
Balance at the end of the period	331		331		73
Deferred Offering Costs
Deferred Offering Costs Noncurrent	68		68		345
Other Assets
Deposits with service providers that are to be applied to future payments	$ 980		$ 980		$ 980
Dividend attributable to down round feature of warrants				303
Incremental borrowing rate	8.00%		8.00%
January 2020 Private Placement
Other Assets
Exercise price of warrant	$ 1.055		$ 1.055			$ 2.11	$ 1.75
Dividend attributable to down round feature of warrants				$ 303

Summary of Significant Accoun_5

Summary of Significant Accounting Policies - Fair Value of Financial Instruments (Details) - USD ($) $ in Thousands	6 Months Ended		12 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Assets:
Cash equivalents	$ 34,758		$ 51,116
Total assets	34,758		51,116
Liabilities:
Restricted stock liability	(204)	$ (159)	204
Total liabilities			204
Level 1
Assets:
Cash equivalents	34,758		51,116
Total assets	$ 34,758		51,116
Level 2
Liabilities:
Restricted stock liability			204
Total liabilities			$ 204

BeiGene Exclusive Option and _3

BeiGene Exclusive Option and License Agreement - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Jan. 03, 2020
BeiGene Exclusive Option and License Agreement
Up-front fee			$ 3,000
Contract acquisition costs	$ 270		270
Amortization expense	34	$ 34	68	$ 68
Deferred Costs	68		68
Exclusive Option and License Agreement
BeiGene Exclusive Option and License Agreement
Future option exercise and milestone payments, maximum					$ 132,000
License
BeiGene Exclusive Option and License Agreement
Revenue recognized	375	$ 375	750	750
Royalty
BeiGene Exclusive Option and License Agreement
Revenue recognized			0	$ 0
Exclusive Option and License Agreement
BeiGene Exclusive Option and License Agreement
Upfront cash payment	$ 3,000		$ 3,000		$ 3,000

BeiGene Exclusive Option and _4

BeiGene Exclusive Option and License Agreement - Contract Liabilities (Details) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2021	Dec. 31, 2020
Contract liabilities
Balance	$ 1,500
Additions		$ 3,000
Deductions	(750)	(1,500)
Balance	$ 750	$ 1,500

Accrued Expenses (Details)

Accrued Expenses (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Accrued Expenses
Clinical trials	$ 1,370	$ 795
Professional fees	166	255
Payroll and related expenses	1,073	1,697
Accrued expenses	$ 2,609	$ 2,747

Leases (Details)

Leases (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Right of use assets, net	$ 337		$ 337		$ 528
Lease liability	354		354
Rent expense	105	$ 142	210	$ 340
Restatement Adjustment | Accounting Standards Update 2016-02 [Member]
Lease liability	$ 354		$ 354

Leases - Future minimum lease p

Leases - Future minimum lease payments (Details) $ in Thousands	Jun. 30, 2021USD ($)
Leases
2021	$ 219
2022	146
Total Lease Payments	365
Less: Imputed Interest	(11)
Total operating lease liabilities	$ 354

Warrants - (Details)

Warrants - (Details) - USD ($) $ / shares in Units, $ in Thousands	Jun. 22, 2020	Mar. 05, 2020	Jan. 03, 2020	Jun. 30, 2020	Jun. 30, 2021	Dec. 31, 2020	Feb. 05, 2019
Warrants
Number of Shares Issuable					52,692,755
Warrant, Down Round Feature, (Increase) Decrease in Equity, Amount				$ 303
2017 Warrants
Warrants
Number of Shares Issuable					2,539,409
Exercise price of warrant					$ 1.055	$ 1.75
2019 Warrants
Warrants
Number of Shares Issuable					7,489,893		7,557,142
Exercise price of warrant					$ 1.95		$ 1.95
January 2020 Warrants | Series A Convertible Preferred Stock
Warrants
Exercise price of warrant		$ 0.001
Issuance of Series A & B Convertible Preferred Stock, net of underwriting discounts (in shares)			1,421,801
Purchase price			$ 10.54
Warrant to purchase shares of common stock		14,413,902
January 2020 Warrants | Series B Convertible Preferred Stock
Warrants
Exercise price of warrant		$ 2.11
Issuance of Series A & B Convertible Preferred Stock, net of underwriting discounts (in shares)			1,137,442
Purchase price			$ 10.55
Conversion of Stock, Shares Issued		11,531,133
March 2020
Warrants
Number of Shares Issuable					14,413,902
Exercise price of warrant					$ 0.001
March 2020
Warrants
Number of Shares Issuable					25,945,035
Exercise price of warrant					$ 2.11
June 2020
Warrants
Number of Shares Issuable					2,250,000
Exercise price of warrant	$ 0.001				$ 0.001
Warrant to purchase shares of common stock	2,250,000
June 2020 | Common Stock
Warrants
Issuance of Series A & B Convertible Preferred Stock, net of underwriting discounts (in shares)	20,250,000
Purchase price	$ 2
June 2020 | Common Stock
Warrants
Issuance of Series A & B Convertible Preferred Stock, net of underwriting discounts (in shares)	20,250,000
1/23/2017
Warrants
Number of Shares Issuable					54,516
Exercise price of warrant					$ 0.01

Common Stock - Private Placemen

Common Stock - Private Placement of Common Stock (Details) $ / shares in Units, $ in Thousands	Jan. 03, 2020USD ($)$ / sharesshares	Jun. 30, 2021USD ($)item$ / shares	Dec. 31, 2020$ / shares	Jun. 30, 2020USD ($)	Mar. 05, 2020$ / sharesshares	Jan. 31, 2020$ / shares
Private Placement of Common Stock
Number of Vote on Common Shares | item		1
Dividends, Common Stock | $		$ 0
Common Stock, Par or Stated Value Per Share		$ 0.001	$ 0.001
January 2020 Private Placement
Private Placement of Common Stock
Exercise price of warrant		$ 1.055			$ 2.11	$ 1.75
Fixed cumulative percentage per annum		8.00%
Cumulative Dividends | $				$ 372
January 2020 Private Placement | Series A Preferred
Private Placement of Common Stock
Common stock issued | shares	1,421,801
Price per share (in dollars per share)	$ 10.54
Net proceeds from issuance of stock in private placement | $	$ 25,322
Convertible Preferred Stock, Shares Issued upon Conversion | shares					14,413,902
Common Stock, Par or Stated Value Per Share					$ 0.001
Value of beneficial conversion features | $	$ 5,226
January 2020 Private Placement | Series B Preferred
Private Placement of Common Stock
Common stock issued | shares	1,137,442
Price per share (in dollars per share)	$ 10.55
Convertible Preferred Stock, Shares Issued upon Conversion | shares					11,531,133
Common Stock, Par or Stated Value Per Share					$ 0.001
Value of beneficial conversion features | $	$ 4,173

Common stock - Public Offering

Common stock - Public Offering of Common Stock (Details) - June 2020 - USD ($) $ / shares in Units, $ in Thousands	Jun. 25, 2020	Jun. 22, 2020	Jun. 30, 2021
Warrant to purchase shares of common stock		2,250,000
Exercise price of warrant		$ 0.001	$ 0.001
Common Stock
Common stock issued		20,250,000
Issue price		$ 2
Net proceeds from issuance of common stock	$ 48,276
Underwriters' exercise | Common Stock
Common stock issued	3,375,000
Common Stock
Common stock issued		20,250,000

Equity Incentive Plans - Equity

Equity Incentive Plans - Equity Incentive Plans (Details) - USD ($) $ in Thousands	Jan. 20, 2017	Jan. 31, 2021	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Stock-Based Compensation
Restricted stock liability							$ 204
Allocated Share-based Compensation Expense			$ 776	$ 539	$ 1,490	$ 1,096
Restricted Stock Units (RSUs)
Stock-Based Compensation
Restricted stock liability							$ 204
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Fair Value					1,645
Share-based Payment Arrangement, Nonvested Award, Excluding Option, Cost Not yet Recognized, Amount			1,141		$ 1,141
Restricted Stock Units (RSUs) | Executive Officer [Member]
Stock-Based Compensation
ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsSettledInCash		92,500
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period					275,000	660,606
Allocated Share-based Compensation Expense			$ 136	$ 78	$ 255	$ 91
2016 Plan
Stock-Based Compensation
Annual increase in authorized shares (as a percent)	4.00%
Number of options or stock awards available for grant under the Plan			456,879		456,879
2016 Plan | Restricted Stock Units (RSUs)
Stock-Based Compensation
Number of options issued under the plan							92,500
ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsSettledInCash					(92,500)
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period					275,000

Equity Incentive Plans - Stock

Equity Incentive Plans - Stock options (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended	3 Months Ended		6 Months Ended		12 Months Ended
	Jan. 31, 2021	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Options
Outstanding balance at the beginning of the period (in shares)	6,393,853			6,393,853
Granted (in shares)				2,336,500
Exercised (in shares)				(2,292)
Forfeited (in shares)				(341,926)
Outstanding balance at the end of the period (in shares)		8,386,135		8,386,135		6,393,853
Options exercisable at the end of the period (in shares)		4,305,584		4,305,584
Options vested and expected to vest at end of period (in shares)		8,386,135		8,386,135
Weighted Average Exercise Price Per Share
Outstanding balance at the beginning of the period (in dollars per share)	$ 5.29			$ 5.29
Granted (in dollars per share)				2.21
Exercised (in dollars per share)				1.55
Forfeited (in dollars per share)				3.19
Outstanding balance at the end of the period (in dollars per share)		$ 4.52		4.52		$ 5.29
Exercisable at the end of the period (in dollars per share)		6.74		6.74
Options vested and expected to vest at end of the period (in dollars per share)		$ 4.52		$ 4.52
Weighted Average Remaining Life in Years
Outstanding balance				8 years 14 days		7 years 11 months 15 days
Options exercisable at end of period				6 years 11 months 26 days
Options vested and expected to vest at end of the period				8 years 14 days
Aggregate Intrinsic Value
Outstanding balance		$ 402		$ 402		$ 1,961
Options exercisable at the end of the period		231		231
Options vested and expected to vest at end of the period		$ 402		$ 402
Assumptions used to determine grant-date fair value
Expected Volatility				66.94%	66.94%
Weighted average risk-free interest rate				0.80%	0.79%
Expected dividend yield				0.00%	0.00%
Expected term (in years)				6 years 10 months 9 days	6 years 10 months 2 days
Expiration period				10 years
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value		$ 2.21	$ 2.18	$ 2.21	$ 2.18
Compensation cost related to the non-vested awards not yet recognized		$ 5,319		$ 5,319
Weighted average period for recognition of compensation cost				2 years 2 months 4 days
Stock-based compensation expense		$ 776	$ 539	$ 1,490	$ 1,096
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Outstanding at end(in dollars per share)		$ 2.21	$ 2.18	$ 2.21	$ 2.18
Research and development
Assumptions used to determine grant-date fair value
Stock-based compensation expense		$ 377	$ 249	$ 707	$ 438
General and administrative
Assumptions used to determine grant-date fair value
Stock-based compensation expense		399	290	$ 783	658
Minimum
Assumptions used to determine grant-date fair value
Vesting period				3 years
Maximum
Assumptions used to determine grant-date fair value
Vesting period				4 years
Restricted Stock Units (RSUs)
Assumptions used to determine grant-date fair value
Weighted average period for recognition of compensation cost				2 years 2 months 1 day
Restricted Stock Units (RSUs) | Executive Officer [Member]
Assumptions used to determine grant-date fair value
Stock-based compensation expense		$ 136	$ 78	$ 255	$ 91
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Awarded				275,000	660,606
Settled in cash	92,500
Restricted Stock Units (RSUs) | 2016 Plan
Assumptions used to determine grant-date fair value
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value		$ 1.76		$ 1.76		$ 1.52
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Outstanding at the beginning	753,106			753,106
Awarded				275,000
Settled in cash				(92,500)
Outstanding at the end		935,606		935,606		753,106
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Outstanding at beginning( in dollars per share)	$ 1.52			$ 1.52
Awarded (in dollars per share)				2.57
Settled in cash(in dollars per share)				1.97
Outstanding at end(in dollars per share)		$ 1.76		$ 1.76		$ 1.52

Net Loss Per Share - Basic and

Net Loss Per Share - Basic and Diluted (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Numerator:
Net loss	$ (9,526)	$ (6,516)	$ (18,660)	$ (13,747)
Dividend attributable to down round feature of warrants				(303)
Dividend attributable to Series A & B convertible preferred stock				(372)
Series A & B convertible preferred stock - beneficial conversion feature				(9,399)
Net loss attributable to common stockholders for basic and diluted loss per share	$ (9,526)	$ (6,516)	$ (18,660)	$ (23,821)
Denominator:
Weighted average number of common shares outstanding - basic and diluted (in shares)	76,389,525	52,442,597	76,384,077	42,037,405
Net loss per share attributable to common stockholders - basic and diluted (in dollars per share)	$ (0.12)	$ (0.12)	$ (0.24)	$ (0.57)
Exercise of the pre-funded warrants			16,718,418

Net Loss Per Share - Antidiluti

Net Loss Per Share - Antidilutive (Details) - shares	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Securities excluded from computation of diluted net loss per share
Anti-dilutive securities excluded from calculation of diluted net loss per share	45,296,078	42,183,070	45,296,078	42,183,070
Restricted Stock Units (RSUs)
Securities excluded from computation of diluted net loss per share
Anti-dilutive securities excluded from calculation of diluted net loss per share	935,606	660,606	935,606	660,606
Options to purchase common stock
Securities excluded from computation of diluted net loss per share
Anti-dilutive securities excluded from calculation of diluted net loss per share	8,386,135	5,481,631	8,386,135	5,481,631
Warrants to purchase common stock
Securities excluded from computation of diluted net loss per share
Anti-dilutive securities excluded from calculation of diluted net loss per share	35,974,337	36,040,833	35,974,337	36,040,833

Commitments and Contingencies -

Commitments and Contingencies - Manufacturing, License and Other Agreements (Details) $ in Thousands	Jun. 30, 2021USD ($)
Commitments and Contingencies
Manufacturing commitments	$ 2,000
License and service agreements
Commitments and Contingencies
Royalties paid or accrued	0
Licensing agreements
Commitments and Contingencies
Royalties paid or accrued	$ 0

Commitments and Contingencies_2

Commitments and Contingencies - Legal Proceedings (Details)	1 Months Ended
	Mar. 31, 2017entity
Commitments and Contingencies
Number filing notice of opposition	10