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Document and Entity Information - USD ($) $ in Millions	12 Months Ended
Document and Entity Information - USD ($) $ in Millions	Dec. 31, 2018	Mar. 26, 2019	Jun. 29, 2018
Document and Entity Information
Entity Registrant Name	LEAP THERAPEUTICS, INC.
Entity Central Index Key	0001509745
Document Type	10-K
Document Period End Date	Dec. 31, 2018
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	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 Public Float			$ 73.4
Entity Common Stock, Shares Outstanding		22,260,301
Document Fiscal Year Focus	2018
Document Fiscal Period Focus	FY

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 16,284	$ 25,737
Research and development incentive receivable	836	1,744
Prepaid expenses and other current assets	202	177
Total current assets	17,322	27,658
Property and equipment, net	86	135
Deferred tax assets	124	158
Other assets	1,542	1,111
Total assets	19,074	29,062
Current liabilities:
Accounts payable	3,579	2,622
Accrued expenses	2,872	3,461
Total current liabilities	6,451	6,083
Non current liabilities:
Warrant liability	3,448	11,862
Total liabilities	9,899	17,945
Commitments and contingencies (Note 13)
Stockholders' equity:
Common stock, $0.001 par value; 100,000,000 shares authorized as of December 31, 2018 and 2017, 14,703,159 and 12,354,014 shares issued and outstanding as of December 31, 2018 and 2017, respectively	15	12
Additional paid-in capital	162,393	141,770
Accumulated other comprehensive income (loss)	302	(268)
Accumulated deficit	(153,535)	(130,397)
Total stockholders' equity	9,175	11,117
Total liabilities and stockholders' equity	$ 19,074	$ 29,062

CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Dec. 31, 2018	Dec. 31, 2017
CONSOLIDATED BALANCE SHEETS
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, authorized shares	100,000,000	100,000,000
Common stock, issued shares	14,703,159	12,354,014
Common stock, outstanding shares	14,703,159	12,354,014

CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Operating expenses:
Research and development	$ 21,830	$ 22,503
General and administrative	8,921	9,849
Total operating expenses	30,751	32,352
Loss from operations	(30,751)	(32,352)
Interest income	447	170
Interest expense	(19)	(528)
Interest expense - related party		(121)
Australian research and development incentives	756	1,715
Foreign currency gains (loss)	(835)	759
Change in fair value of warrant liability	7,284	473
Loss before income taxes	(23,118)	(29,884)
Income taxes	(20)	157
Net loss	(23,138)	(29,727)
Accretion of preferred stock to redemption value		(244)
Net loss attributable to common stockholders	$ (23,138)	$ (29,971)
Net loss per share
Basic (in dollars per share)	$ (1.64)	$ (3.27)
Diluted (in dollars per share)	$ (2.11)	$ (3.31)
Weighted average common shares outstanding
Basic (in shares)	14,144,287	9,161,844
Diluted (in shares)	14,412,695	9,188,587

CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS
Net loss	$ (23,138)	$ (29,727)
Other comprehensive loss:
Foreign currency translation adjustments	570	(562)
Comprehensive loss	$ (22,568)	$ (30,289)

- Definition

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

+ References + Details

CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (DEFICIENCY) - USD ($) $ in Thousands	Common Stock Subscription Agreement	Common Stock Private Placement	Common Stock Public Offering	Common Stock	Additional Paid-in Capital Subscription Agreement	Additional Paid-in Capital Private Placement	Additional Paid-in Capital Public Offering	Additional Paid-in Capital	Other Comprehensive Loss	Accumulated Deficit	Subscription Agreement	Private Placement	Public Offering	Total
Balance at the beginning of the period at Dec. 31, 2016								$ 145	$ 294	$ (100,670)				$ (100,231)
Increase (Decrease) in Stockholders' Equity
Accretion of redeemable preferred stock to redemption value								(244)						(244)
Conversion of notes payable-related party and accrued interest into common stock				$ 2				31,143						31,145
Conversion of notes payable-related party and accrued interest into stock (in shares)				1,950,768
Conversion of convertible preferred stock to common stock				$ 3				70,772						70,775
Conversion of convertible preferred stock to common stock (in shares)				3,174,523
Issuance of common stock, net of issuance costs	$ 1	$ 3			$ 8,981	$ 5,426					$ 8,982	$ 5,429
Issuance of stock (in shares)	1,010,225	2,958,094
Issuance of common stock in connection with merger with Macrocoure, net of offering costs of $1,331				$ 3				19,927						19,930
Issuance of common stock in connection with merger with Macrocoure, net of offering costs of $1,331 (in shares)				3,256,898
Issuance of common stock upon exercise of stock options								20						$ 20
Issuance of common stock upon exercise of stock options (in shares)				3,506										3,506
Foreign currency translation adjustment									(562)					$ (562)
Stock-based compensation								5,600						5,600
Net loss										(29,727)				(29,727)
Balance at the end of the period at Dec. 31, 2017				$ 12				141,770	(268)	(130,397)				11,117
Balance at the end of the period (in shares) at Dec. 31, 2017				12,354,014
Increase (Decrease) in Stockholders' Equity
Issuance of common stock, net of issuance costs			$ 3				$ 14,793						$ 14,796
Issuance of stock (in shares)			2,146,667
Issuance of common stock upon exercise of warrants								2,347						2,347
Issuance of common stock upon exercise of warrants (in shares)				200,000
Issuance of common stock upon exercise of stock options								14						$ 14
Issuance of common stock upon exercise of stock options (in shares)				2,478										2,478
Foreign currency translation adjustment									570					$ 570
Stock-based compensation								3,469						3,469
Net loss										(23,138)				(23,138)
Balance at the end of the period at Dec. 31, 2018				$ 15				$ 162,393	$ 302	$ (153,535)				$ 9,175
Balance at the end of the period (in shares) at Dec. 31, 2018				14,703,159

CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (DEFICIENCY) (Parenthetical) $ in Thousands	12 Months Ended
	Dec. 31, 2017 USD ($)
CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (DEFICIENCY)
Reclassification of deferred offering costs to additional paid-in capital	$ 1,331
Subscription Agreement
CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (DEFICIENCY)
Issuance of common stock, issuance costs	1,018
Private Placement
CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (DEFICIENCY)
Issuance of common stock, issuance costs	$ 236

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Cash flows from operating activities:
Net loss	$ (23,138)	$ (29,727)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation expense	49	48
Stock-based compensation expense	3,469	5,600
Non-cash interest expense - related party		121
Change in fair value of warrant liability	(7,284)	(473)
Changes in operating assets and liabilities, net of impact of assumed net assets of Macrocure:
Prepaid expenses and other assets	(297)	(99)
Deferred tax assets	20	(158)
Research and development incentive receivable	780	1,458
Accounts payable and accrued expenses	368	1,093
Net cash used in operating activities	(26,033)	(22,137)
Cash flows from investing activities:
Purchases of property and equipment		(64)
Net cash used in investing activities		(64)
Cash flows from financing activities:
Proceeds from issuance of common stock in connection with merger with Macrocure		21,165
Proceeds from issuance of common stock in connection with Subscription Agreement		10,000
Proceeds from issuance of common stock in connection with Private Placement		18,000
Proceeds from issuance of common stock, net of underwriter commissions and discounts	15,034
Proceeds from notes payable - related party		750
Proceeds from exercise of common stock warrants	1,217
Proceeds from the exercise of stock options	14	20
Payment of offering costs	(359)	(2,172)
Net cash provided by financing activities	15,906	47,763
Effect of exchange rate changes on cash and cash equivalents	674	(618)
Net increase (decrease) in cash and cash equivalents	(9,453)	24,944
Cash and cash equivalents at beginning of period	25,737	793
Cash and cash equivalents at end of period	16,284	25,737
Supplemental disclosure of non-cash financing activities:
Accretion of preferred stock to redemption value		244
Reduction in fair value of warrant liability as a result of exercise of common stock warrants	1,130
Deferred offering costs included in accounts payable and accrued expenses	$ 41	131
Conversion of notes payable-related party and accrued interest convertible preferred stock into common stock		31,145
Conversion of convertible preferred stock into common stock		70,775
Value of net assets acquired in connection with merger with Macrocure, excluding cash		$ 96

Nature of Business, Basis of Presentation and Liquidity	12 Months Ended
Nature of Business, Basis of Presentation and Liquidity	Dec. 31, 2018
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 as Dekkun Corporation on January 3, 2011 and changed its name to HealthCare Pharmaceuticals, Inc. effective May 29, 2014, and then to Leap Therapeutics, Inc. effective November 16, 2015 (the “Company”). During 2015, HealthCare Pharmaceuticals Pty Ltd (“HCP Australia”) was formed and is a wholly owned subsidiary of the Company. During 2017, the Company merged with Macrocure Ltd. (now “Leap Therapeutics Ltd.”) and its wholly owned subsidiary Macrocure, Inc. 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 consolidated financial statements of the Company include the accounts of its wholly owned subsidiaries and have been prepared in conformity with accounting principles generally accepted in the United States of America. All inter-company accounts and transactions are eliminated upon consolidation. Merger with Macrocure Ltd. The Company entered into a definitive merger agreement (the “Merger Agreement”), dated as of August 29, 2016, with Macrocure Ltd. (“Macrocure”), a publicly held, clinical-stage biotechnology company based in Petach Tikva, Israel, and M-Co Merger Sub Ltd. (“Merger Sub”), a wholly owned subsidiary of the Company which provided for the merger of Macrocure with and into Merger Sub, with Macrocure continuing after the merger as a wholly owned subsidiary of the Company. Following the merger, the Company changed Macrocure’s name to Leap Therapeutics Ltd. Pursuant to the Merger Agreement, the existing equity holders of the Company invested an additional $10,000 at the closing of the transaction. On January 23, 2017, the Company issued 3,256,898 shares of its common stock in exchange for 100% of the outstanding ordinary shares of Macrocure Ltd. upon consummation of the merger (see Note 3). Reverse Stock Split On January 20, 2017, the Company effected a 1-for-19.86754 reverse stock split of its issued and outstanding shares of common stock and a proportional adjustment to the existing conversion ratios for each series of the Company’s Preferred Stock. Accordingly, all share and per share amounts for all periods presented in the accompanying consolidated financial statements and notes thereto have been adjusted retroactively, where applicable, to reflect this reverse stock split and adjustment of the preferred stock conversion ratios. 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 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 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 within one year after the date that the consolidated financial statements are issued. As of December 31, 2018, the Company had an accumulated deficit of $153,535. During the year ended December 31, 2018, the Company incurred a loss of $23,138 and used $26,033 of cash in operations. The Company expects to continue to generate operating losses in the foreseeable future. On February 5, 2019, the Company completed a public offering whereby it issued 7,557,142 shares of its common stock and warrants to acquire 7,557,142 shares of its common stock at a price of $1.75 per unit, which included 985,714 shares and warrants to acquire 985,714 shares issued pursuant to the underwriters’ exercise of their option to purchase additional securities. The aggregate net proceeds received by the Company from the offering were approximately $12,081, net of underwriting discounts and commissions and estimated offering expenses. The Company believes that its cash and cash equivalents of $16,284 as of December 31, 2018, together with the net proceeds from the February 2019 Public Offering and the receipt of $836 of research and development tax incentive payments from the Commonwealth of Australia as a result of the 2018 research and development activities of the Company’s Australian subsidiary, HealthCare Pharmaceuticals Pty Ltd, net of the current Australia tax liability, will be sufficient to fund its operating expenses for at least the next 12 months from issuance of the 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 cost-sharing, or exceeds its current spending forecasts or fails to receive the research and development tax incentive payment, the Company has the ability and 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, any of 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 Accounting Policies

12 Months Ended

Dec. 31, 2018

Summary of Significant Accounting Policies

Summary of Significant Accounting Policies

2. Summary of Significant Accounting Policies

Principles of Consolidation

The accompanying 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 consolidated financial statements in conformity with accounting principles generally accepted in the United States of America (“GAAP”) requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the consolidated financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates.

Cash and Cash Equivalents

The Company considers all highly liquid investments with maturities of three months or less when purchased to be cash equivalents.

Research and Development Expense

Research and development costs are expensed as incurred. Research and development expenses include personnel costs associated with research and development activities, including noncash share-based compensation and costs for third-party contractors to perform research, conduct clinical trials and manufacture drug supplies and materials. The Company accrues for costs incurred by external service providers, including contract research organizations and clinical investigators, based on its estimates of service performed and costs incurred. These estimates include the level of services performed by the third parties, patient enrollment in clinical trials, administrative costs incurred by the third parties, and other indicators of the services completed. Based on the timing of amounts invoiced by service providers, the Company may also record payments made to those providers as prepaid expenses that will be recognized as expense in future periods as the related services are rendered.

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. This estimate is also reviewed by external tax advisors on an annual basis.

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 years ended December 31, 2018 and 2017.

The research and development incentive receivable represents an amount due in connection with the above program. The Company has recorded a research and development incentive receivable of $836 and $1,744 as of December 31, 2018 and 2017, respectively, in the consolidated balance sheets and other income from Australian research and development incentives of $756 and $1,715, in the consolidated statements of operations for the years ended December 31, 2018 and 2017, respectively, 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, 2017 to December 31, 2018:


Balance at January 1, 2017	$	3,053
Australian research and development incentive income		1,715	(1)
Cash received for 2016 eligible expenses		(3,245)
Foreign currency translation		221
Balance at December 31, 2017		1,744
Australian research and development incentive income		756
Cash received for 2016 eligible overseas research and development expenses		(740)
Cash received for 2017 eligible expenses		(793)
Foreign currency translation		(131)
Balance at December 31, 2018	$	836

(1)

Certain supporting research and development activity is performed outside of Australia when there are no Australian facilities that support the activity (“Overseas research and development activities”). In October 2017, the Commonwealth of Australia issued the Company a favorable ruling on its Overseas research and development activities, considering such activities to be eligible research and development activities under the Australian Incentive Program. As such, the Company recorded Australian research and development incentives during the year ended December 31, 2017 for its Overseas research and development activities performed during the year ended December 31, 2016 of $717.

Concentration of Credit Risk

Financial instruments which potentially subject the Company to credit risk consist principally of cash and cash equivalents. All cash and cash equivalents are held in United States financial institutions and money market funds. At times, the Company may maintain cash balances in excess of the federally insured amount.

Income Taxes

The Company accounts for income taxes using the asset and liability method. Under the asset and liability method, deferred income taxes are recognized for differences between the financial reporting and tax bases of assets and liabilities at enacted statutory tax rates in effect for the years in which the differences are expected to reverse. The effect on deferred taxes of a change in tax rates is recognized in income in the period that includes the enactment date. Valuation allowances are established when necessary to reduce deferred tax assets to the amount expected to be realized.

The Company follows accounting guidance concerning provisions for uncertainty in income tax positions. This guidance clarifies the accounting for income taxes by prescribing a minimum probability threshold that an uncertain tax position must meet before a financial statement benefit is recognized. The minimum threshold is defined as a tax position that is more likely than not to be sustained upon examination by the applicable taxing authority, of any related appeals or litigation processes, based on the technical merits of the position. The tax benefit to be recognized is measured as the largest amount of benefit that is greater than 50% likely of being realized upon ultimate settlement.

The Company recognizes accrued interest and penalties associated with uncertain tax position as part of the income tax provision. There were no uncertain tax positions or income tax related interest and penalties recorded for the years ended December 31, 2018 and 2017. The income tax returns of the Company for the year ended December 31, 2015 and subsequent years are subject to examination by the Internal Revenue Service and other taxing authorities, generally for three years after the returns were filed.

Foreign Currency Translation

The financial statements of the Company’s foreign subsidiary are measured using the local currency as the functional currency. Assets and liabilities of this subsidiary are translated into U.S. dollars at exchange rates 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 year. The resulting cumulative translation adjustments have been recorded as a separate component of stockholders’ deficiency. Foreign currency transaction gains and losses are included in the results of operations.

Property and Equipment

Property and equipment are stated at cost less accumulated depreciation. Depreciation expense is recognized using the straight-line method over the estimated useful life of each asset. Computer equipment is depreciated over three years. Laboratory equipment, office equipment and furniture and fixtures are depreciated over five years. Leasehold improvements are amortized over the shorter of the lease term or the estimated useful life of the asset. Upon retirement or sale, the cost of assets disposed of and the related accumulated depreciation are removed from the accounts and any resulting gain or loss is included in loss from operations. Expenditures for repairs and maintenance are charged to expense as incurred.

Impairment of Long-Lived Assets

Long-lived assets consist of property and equipment. Long-lived assets to be held and used are tested for recoverability whenever events or changes in business circumstances indicate that the carrying amount of the assets may not be fully recoverable. Factors that the Company considers in deciding when to perform an impairment review include significant underperformance of the business in relation to expectations, significant negative industry or economic trends and significant changes or planned changes in the use of the assets. If an impairment review is performed to evaluate a long-lived asset group for recoverability, the Company compares forecasts of undiscounted cash flows expected to result from the use and eventual disposition of the long-lived asset group to its carrying value. An impairment loss would be recognized when estimated undiscounted future cash flows expected to result from the use of an asset group are less than its carrying amount. The impairment loss would be based on the excess of the carrying value of the impaired asset group over its fair value, determined based on discounted cash flows. To date, the Company has not recorded any impairment losses on long-lived assets.

Deferred Offering Costs

The Company capitalizes certain legal, professional accounting and other third-party fees that are directly associated with in-process equity financings as deferred offering costs until such financings are consummated. After consummation of the equity financing, these costs are recorded in stockholders’ equity (deficiency) as a reduction of additional paid-in capital generated as a result of the offering. As of December 31, 2018, there was $162 of deferred offering costs included in other assets in the consolidated balance sheets.

Other Assets

Other assets as of December 31, 2018 and 2017, consist of $1,380 and $1,111, respectively, 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.

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 years presented, the Company has not changed the manner in which it values assets and liabilities that are measured at fair value using Level 3 inputs. The Company recognizes transfers between levels of the fair value hierarchy as of the end of the reporting period. There were no transfers within the hierarchy during the years ended December 31, 2018 and 2017.

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
December 31, 2018
Assets:
Cash equivalents	$	16,284	$	16,284	$	—	$	—
Total assets	$	16,284	$	16,284	$	—	$	—

Liabilities:
Warrant liability	$	3,448	$	—	$	—	$	3,448
Total liabilities	$	3,448	$	—	$	—	$	3,448

December 31, 2017
Assets:
Cash equivalents	$	25,737	$	25,737	$	—	$	—
Total assets	$	25,737	$	25,737	$	—	$	—

Liabilities:
Warrant liability	$	11,862	$	—	$	—	$	11,862
Total liabilities	$	11,862	$	—	$	—	$	11,862

Cash equivalents of $16,284 and $25,737 as of December 31, 2018 and 2017, 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 value of the research and development incentive receivable, accounts payable and accrued expenses approximate their fair value due to the short-term nature of these assets and liabilities.

A roll-forward of the recurring fair value measurements of the warrant liability categorized with Level 3 inputs are as follows (in thousands):


	Warrant
	Liability
Balance-January 1, 2017	$	—
Initial fair value		12,335
Change in fair value		(473)
Balance-December 31, 2017		11,862
Exercise of warrants		(1,130)
Change in Fair value		(7,284)
Balance-December 31, 2018	$	3,448

The warrant liability in the table above is composed of the fair value of warrants to purchase common shares that the Company issued in connection with the Private Placement (see Notes 7 and 9). The fair value of the warrant liability was determined based on significant inputs not observable in the market, which represents a Level 3 measurement within the fair value hierarchy. The Company utilized a Monte Carlo simulation, which is a statistical method used to generate a defined number of share price paths to develop a reasonable estimate of the range of the future expected share prices, to value the warrant liability. The Monte Carlo simulation incorporated assumptions and estimates to value the warrant liability. Estimates and assumptions impacting the fair value measurement included the estimated probability of adjusting the exercise price of the warrants, the number of shares for which the warrants will be exercisable, the remaining contractual term of the warrants, the risk-free interest rate, the expected dividend yield, and the expected volatility of the price of the underlying common shares.

The Company historically had been a private company and lacks company-specific historical and implied volatility information of its shares. Therefore, it estimated its expected share volatility based on the historical volatility of publicly traded peer companies for a term equal to the remaining contractual term of the warrants. The risk-free interest rate was determined by reference to the U.S. Treasury yield curve for time periods approximately equal to the remaining contractual term of the warrants. The Company estimated a 0% expected dividend yield based on the fact that the Company has never paid or declared dividends and does not intend to do so in the foreseeable future.

Segment Information

The Company manages its operations as a single segment for the purposes of assessing performance and making operating decisions. The Company’s singular focus is developing novel, targeted drugs for the treatment of cancer. Substantially all of the Company’s tangible assets are held in the United States.

Patent Costs

All patent related costs incurred in connection with filing and prosecuting patent applications are expensed as incurred due to the uncertainty about the recovery of the expenditure. Amounts incurred are classified as general and administrative expenses.

Stock-Based Compensation

The Company measures all stock options and other stock-based awards granted to employees based on the fair value on the date of the grant and recognizes compensation expense of those awards, net of estimated forfeitures, over the requisite service period, which is generally the vesting period of the respective award. Generally, the Company issues stock options to employees with only service-based vesting conditions and records the expense for these awards using the straight-line method.

The Company measures stock-based awards granted to consultants and nonemployees based on the fair value of the award on the date on which the related service is complete. Compensation expense is recognized over the period during which services are rendered by such consultants and nonemployees until completed. At the end of each financial reporting period prior to completion of the service, the fair value of these awards is remeasured using the then current fair value of the Company’s common stock and updated assumption inputs in the Black-Scholes option-pricing model.

Stock-based compensation is classified in the accompanying consolidated statements of operations based on the function to which the related services are provided. The Company recognizes compensation expense for only the portion of awards that are expected to vest. In developing a forfeiture rate estimate, the Company has considered its historical experience to estimate pre-vesting forfeitures for service-based awards. The impact of a forfeiture rate adjustment will be recognized in full in the period of adjustment, and if the actual forfeiture rate is materially different from the Company’s estimate, the Company may be required to record adjustments to stock-based compensation expense in future periods.

The fair value of each stock option grant is estimated on the date of grant using the Black-Scholes option-pricing model. The Company historically has been a private company and lacks company-specific historical and implied volatility information. Therefore, it estimates its expected stock volatility based on the historical volatility of a publicly traded set of peer companies and expects to continue to do so until such time as it has adequate historical data regarding the volatility of its own traded stock price. The expected term of the Company’s stock options has been determined utilizing the “simplified” method for awards that qualify as “plain-vanilla” options. The expected term of stock options granted to nonemployees is equal to the contractual term of the option award. The risk-free interest rate is determined by reference to the U.S. Treasury yield curve in effect at the time of grant of the award for time periods approximately equal to the expected term of the award. Expected dividend yield is based on the fact that the Company has never paid cash dividends on common stock and does not expect to pay any cash dividends in the foreseeable future.

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.

Reclassification

Certain prior period amounts have been reclassified for consistency with the current period presentation. These reclassifications had no effect on previously reported results of operations.

During the three months ended March 31, 2018, the Company made a policy election to present the change in fair value of its warrant liability separate from interest expense within its consolidated statements of operations on a prospective basis. The reclassification had no impact on the Company’s previously reported financial position or cash flows.

Redeemable Convertible Preferred Stock

On January 20, 2017, in connection with and prior to the completion of the merger with Macrocure, all of the Company’s outstanding shares of convertible preferred stock were converted into 3,174,523 shares of common stock.

Warrant Liability

In connection with entering into the Private Placement (Note 9), the Company issued a warrant to purchase common stock with each share of common stock sold in the Private Placement. The Company classified the warrants as a liability on its consolidated balance sheet because each warrant represents a freestanding financial instrument that is not indexed to the Company’s own shares. The warrant liability was initially recorded at fair value upon entering into the Private Placement agreement and is subsequently remeasured to fair value at each reporting date. Changes in the fair value of the warrant liability are recognized in the consolidated statements of operations. Changes in the fair value of the warrant liability will continue to be recognized until the warrants are exercised, expire or qualify for equity classification.

If the Company issues shares to discharge the liability, the derivative financial liability is derecognized and common stock and additional paid-in capital are recognized on the issuance of those shares. Warrants are valued using the Monte Carlo simulation model. If the terms of warrants that initially require the warrant to be classified as a liability lapse, the liability is reclassified out of financial liabilities into equity at its fair value on that date. The cash proceeds received from exercises of warrants are recorded in common stock and additional paid-in capital.

Recent Accounting Pronouncements

From time to time, new accounting pronouncements are issued by the Financial Accounting Standards Board, or FASB, and are early adopted by the Company or adopted as of the specified effective date.

In March 2016, the FASB issued ASU 2016‑09, Compensation—Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting. The new standard involves several aspects of the accounting for share-based payment transactions, including the income tax consequences, classification of awards as either equity or liabilities and classification on the statement of cash flows. The Company adopted this standard effective January 1, 2018, which had no impact on the Company’s consolidated financial statements.

In August 2016, the FASB issued ASU No. 2016‑15, Statement of Cash Flows: Classification of Certain Cash Receipts and Cash Payments (“ASU 2016‑15”), to address diversity in practice in how certain cash receipts and cash payments are presented and classified in the statement of cash flows. The standard is effective for the Company for annual periods beginning after December 15, 2018, including interim periods within those fiscal years. The Company adopted this standard effective January 1, 2018, which had no impact on the Company’s consolidated financial statements.

In May 2017, the FASB issued ASU No. 2017-09, Compensation—Stock Compensation (Topic 718): Scope of Modification Accounting (“ASU 2017-09”), which clarifies when to account for a change to the terms or conditions of a share-based payment award as a modification. Under the new guidance, modification accounting is required only if the fair value, the vesting conditions, or the classification of the award (as equity or liability) changes as a result of the change in terms or conditions. The Company adopted this standard effective January 1, 2018, which had no impact on the Company’s condensed consolidated financial statements.

The Company also considered the following recent accounting pronouncements which were not yet adopted as of December 31, 2018:

In June 2018, the FASB issued ASU No. 2018-07, Compensation—Stock Compensation (Topic 718): Improvements to Nonemployee Share-Based Payment Accounting, which is intended to simplify the accounting for share-based payments to nonemployees by aligning it with the accounting for share-based payments to employees, with certain exceptions. The new guidance is effective for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years. Early adoption is permitted. The Company has evaluated the accounting, transition and disclosure requirements of this standard and does not expect it to have a material impact on the Company’s consolidated financial statements.

In July 2017, the FASB issued ASU No. 2017-11, Earnings Per Share (Topic 260), Distinguishing Liabilities from Equity (Topic 480), and Derivatives and Hedging (Topic 815) (“ASU 2017-11”), which changes the classification analysis of certain equity-linked financial instruments (or embedded features) with down round features. The amendments require entities that present earnings per share (“EPS”) in accordance with Topic 260 to recognize the effect of the down round feature when triggered with the effect treated as a dividend and as a reduction of income available to common shareholders in basic EPS. The new standard is effective for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years. The Company is evaluating the accounting, transition, and disclosure requirements of this standard and believes that it will have a material impact on the Company’s consolidated financial statements. The Company believes that the new standard will change the accounting treatment of the 2017 Warrants from liability to equity classification and that the effect of the adjustment to the exercise price as a result of the “down round” 2019 public offering will be to record a dividend and reduction of income available to common shareholders in basic EPS.

In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842). The new guidance will require lessees to recognize a right-of-use asset and a lease liability for virtually all of their leases (other than leases that meet the definition of a short-term lease). The liability will be equal to the present value of lease payments. The asset will be based on the liability, subject to adjustment, such as for initial direct costs. Under the new guidance, lessor accounting is largely unchanged but certain targeted improvements were made to align, where necessary, lessor accounting with the lessee accounting model and Topic 606, Revenue from Contracts with Customers. The new lease guidance also simplified the accounting for sale and leaseback transactions primarily because lessees must recognize lease assets and lease liabilities and therefore, will no longer be provided with a source of off-balance sheet financing. The new guidance is effective for the Company January 1, 2019. The standard is expected to have a material impact on the Consolidated Balance Sheets, but not have an impact on the Consolidated Statements of Operations. The most significant impact will be the recognition of right-of-use assets and lease liabilities for operating leases, which the Company is currently estimating to be approximately $1,500 to $2,000.

The Company believes that the impact of other recently issued but not yet adopted accounting pronouncements will not have a material impact on the Company’s consolidated financial position, results of operations, and cash flows, or do not apply to the Company’s operations.

Merger with Macrocure and Related Transactions	12 Months Ended
Merger with Macrocure and Related Transactions	Dec. 31, 2018
Merger with Macrocure and Related Transactions
Merger with Macrocure and Related Transactions	3. Merger with Macrocure and Related Transactions Merger with Macrocure Ltd. The Company entered into a definitive merger agreement (the “Merger Agreement”), dated as of August 29, 2016, with Macrocure Ltd. (“Macrocure”), a publicly held, clinical-stage biotechnology company based in Petach Tikva, Israel, and M-Co Merger Sub Ltd. (“Merger Sub”), a wholly owned subsidiary of the Company which provided for the merger of Macrocure with and into Merger Sub, with Macrocure continuing after the merger as a wholly owned subsidiary of the Company. On January 23, 2017, the Company issued 3,256,898 shares of its common stock, net of fractional shares paid in cash, in exchange for 100% of the outstanding ordinary shares of Macrocure Ltd. upon consummation of the merger. Pursuant to the terms of the Merger Agreement, each holder of Macrocure’s ordinary shares received approximately 0.1815 shares of the Company’s common stock, plus cash in lieu of fractional shares based on a value of the Company’s common stock of $9.90 per share. The exchange ratio was based on a final net cash calculation, as of the closing, of $21,875. The merger was accounted for as an in-substance recapitalization of the Company, as the transaction was, in essence, an exchange of shares of the Company’s common stock (and options and warrants exercisable therefor) for cash. Apart from cash, the net assets acquired were $96, and all Macrocure employees were terminated as of the effective time of the merger. Macrocure’s cash and nominal assets and liabilities were measured and recognized at their fair values as of the date of the merger, and combined with the assets, liabilities and results of operations of the Company. All Macrocure stock options granted under the Macrocure stock option plans (whether or not then exercisable) and all warrants to purchase Macrocure ordinary shares that were outstanding prior to the effective time of the merger became options and warrants, respectively, to purchase the Company’s common stock equal to the number of ordinary shares of Macrocure issuable upon exercise of such stock options and warrants multiplied by the exchange ratio, with a corresponding exercise price equal to the exercise price of such stock options or warrants divided by the exchange ratio. All outstanding and unexercised Macrocure stock options and warrants assumed by the Company may be exercised solely for shares of the Company’s common stock. Vesting of all unvested Macrocure equity awards issued and outstanding was accelerated at the effective time of the merger, and all such equity awards issued and outstanding at the time of the merger remained issued and outstanding. For accounting purposes, since the acceleration of vesting was negotiated in contemplation of the merger, the remaining unrecognized compensation expense associated with the original grant date fair value of the awards of $280 was recognized as a charge in the Company’s consolidated statement of operations for the year ended December 31, 2017. In addition, the exercise period for all Macrocure options outstanding at the effective time of the merger was extended beyond the respective periods provided in the original awards. The Company recorded a charge of $504 in connection with the extension of the exercise periods in the consolidated statement of operations for the year ended December 31, 2017 equal to the difference in the fair value of the options immediately prior to and immediately following the modification of the exercise period. In connection with the merger, the Company applied to be listed on the NASDAQ Global Market. NASDAQ approved the listing, and trading in the Company’s common stock commenced on January 24, 2017, under the trading symbol “LPTX”. Recapitalization and Amendments to Certificate of Incorporation On January 20, 2017, in connection with and prior to the completion of the merger with Macrocure, (a) all of the Company’s outstanding shares of convertible preferred stock were converted into 3,174,523 shares of common stock, (b) the outstanding note payable and accrued interest was converted into 1,950,768 shares of common stock, and (c) the Company amended and restated its certificate of incorporation and bylaws to, among other things: (i) authorize 100,000,000 shares of common stock; (ii) eliminate all references to the previously existing series of the Company’s preferred stock; (iii) authorize 10,000,000 shares of undesignated preferred stock that may be issued from time to time by the Company’s board of directors and (iv) effect a one for 19.86754 reverse stock split of the Company’s common stock outstanding immediately prior to the filing of the amended and restated certificate of incorporation. Subscription Agreement On January 20, 2017, prior and subject to the consummation of the merger, the Company and HealthCare Ventures IX, L.P. (“HCV IX”) entered into a subscription agreement pursuant to which HCV IX purchased 1,010,225 shares of the Company’s common stock for $10,000, at a purchase price per share of $9.90. Stock Option Grants On January 20, 2017, in connection with the consummation of the merger with Macrocure, the Company made an option grant to each of three executives to purchase 330,303 of shares of common stock, for a total of 990,909 shares of common stock, pursuant to its Amended and Restated 2012 Equity Incentive Plan. The options were granted at an exercise price of $9.90 per share. The options will vest 33% on the first anniversary of the date of grant, and thereafter in equal monthly installments over a period of two years, generally subject to the executive’s continued employment. Royalty Agreement and Letter Agreement On January 23, 2017, immediately prior to the merger, the Company entered into a royalty agreement with Leap Shareholder Royalty Vehicle, LLC, a Delaware limited liability company (the “Royalty Vehicle”), a special purpose vehicle formed for the specific purpose of entering into the royalty agreement. In connection with the transactions contemplated by the Merger Agreement, the Company declared a special distribution of certain royalty rights to each of its holders of common stock outstanding immediately prior to the effective time of the merger. These holders collectively beneficially owned or controlled 100% of the Company’s outstanding common stock at the time of the merger. Pursuant to the royalty agreement, the Company will pay to the special purpose vehicle (i) 5% of the Company’s net sales of products incorporating its TRX518 compound and (ii) 2% of the Company’s net sales of products incorporating its DKN-01 compound. The royalty agreement has an indefinite term, and neither the Company nor the special purpose vehicle has the right to terminate. The Company accounted for the royalty rights as a contingent liability.

Property and Equipment, Net

12 Months Ended

Dec. 31, 2018

Property and Equipment, Net

Property and Equipment, Net

4. Property and Equipment, Net

Property and equipment, net consisted of the following:


	December 31,
	2018		2017
Computer office equipment	$	51	$	51
Leasehold improvements		69		69
Lab equipment		58		58
Furnitures and fixtures		30		30
		208		208
Less: accumulated depreciation		(122)		(73)
Property and equipment, net	$	86	$	135

Depreciation expense was $49 and $48 for the years ended December 31, 2018 and 2017, respectively.

Accrued Expenses

12 Months Ended

Dec. 31, 2018

Accrued Expenses

Accrued Expenses

5. Accrued Expenses

Accrued expenses consist of the following:


	December 31,
	2018		2017
Clinical trials	$	1,745	$	2,116
Professional fees		219		390
Payroll and related expenses		908		955
Accrued expenses	$	2,872	$	3,461

Notes Payable-Related Party	12 Months Ended
Notes Payable-Related Party	Dec. 31, 2018
Notes Payable-Related Party
Notes Payable-Related Party	6. Notes Payable—Related Party During 2014, the Company entered into a convertible promissory note with a stockholder, and made multiple drawdowns under the note throughout 2014, 2015 and 2016. The note accrued interest at a rate of 8% per year. As of December 31, 2016, the Company owed $29,000 aggregate principal and $1,274 of accrued interest in connection with the promissory note. Interest expense from the related-party note was $121 for the year ended December 31, 2017. On January 13, 2017, the Company received aggregate proceeds of $750 from an amendment and restatement of the promissory note. On January 20, 2017, in accordance with its terms and in connection with and prior and subject to the consummation of the merger with Macrocure, the outstanding note payable, including principal and accrued interest totaling $31,145, was converted into 1,950,768 shares of common stock.

Warrants

12 Months Ended

Dec. 31, 2018

Warrants

Warrants

7. Warrants

As of December 31, 2018, outstanding warrants to purchase common stock consisted of the following:


December 31, 2018
	Number of Shares
Date Exercisable	Issuable	Exercise Price		Exercisable for	Classification
1/23/2017	54,516	$	0.01	Common Stock	Equity
11/14/2017	2,758,094		6.085	Common Stock	Liability
	2,812,610

2017 Warrants

On November 14, 2017, in connection with the Private Placement (see Note 9), the Company issued immediately exercisable warrants to purchase 2,958,094 shares of common stock to investors. The warrants had an initial exercise price of $6.085 per share, and expire on November 14, 2024. During the year ended December 31, 2018, 200,000 warrants were exercised resulting in gross proceeds to the Company of $1,217.

The warrants contain full ratchet anti-dilution protection provisions. The Company classifies the warrants as a liability on its consolidated balance sheet because each warrant represents a freestanding financial instrument that, due to the potential variable nature of the exercise price, is not considered to be indexed to the Company’s own shares. The warrant liability was initially recorded at fair value upon entering into the Private Placement and is subsequently remeasured to fair value at each reporting date. Changes in the fair value of the warrant liability are recognized as a component of other income (expense), net in the Company’s consolidated statement of operations. Changes in the fair value of the warrant liability will continue to be recognized until the warrants are exercised, expire or qualify for equity classification.

As a result of the consummation of the February 2019 Public Offering, the exercise price of the 2017 Warrants automatically was adjusted pursuant to, and in accordance with, their terms, to $1.75 per share.

The fair value of the warrant liability was determined to be $12,335 on the date of issuance. The Company remeasured the liability as of December 31, 2017 and determined that the fair value of the warrant liability was $11,862, resulting in income of $473 recorded in the consolidated statements of operations for the year ended December 31, 2017. As of December 31, 2018, the fair value of the warrant liability was $3,448, resulting in income of $7,284 recorded in the consolidated statements of operations for the year ended December 31, 2018.

Preferred Stock	12 Months Ended
Preferred Stock	Dec. 31, 2018
Preferred Stock
Preferred Stock	8. Preferred Stock On January 1, 2017, the Company had convertible preferred shares which were redeemable outstanding. On January 20, 2017, prior and subject to the consummation of the merger with Macrocure, all outstanding shares of the Company's convertible preferred stock were converted into 3,174,523 shares of common stock. Accretion of the preferred stock to redemption value during 2017 prior to conversion was $244.

Common Stock	12 Months Ended
Common Stock	Dec. 31, 2018
Common Stock
Common Stock	9. 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 December 31, 2018, no dividends have been declared. As of December 31, 2018, the Company had reserved shares of common stock for the exercise of outstanding stock options and warrants, and for the number of shares remaining for grant under the Company’s 2012 and 2016 Equity Incentive Plans (see Note 10). Merger with Macrocure Ltd. On January 20, 2017, in connection with and prior to the completion of the merger with Macrocure, (a) all of the Company’s outstanding shares of convertible preferred stock were converted into 3,174,523 shares of common stock, (b) the outstanding note payable and accrued interest was converted into 1,950,768 shares of common stock, and (c) the Company amended and restated its certificate of incorporation and bylaws to, among other things: (i) authorize 100,000,000 shares of common stock; (ii) eliminate all references to the previously existing series of the Company’s preferred stock; (iii) authorize 10,000,000 shares of undesignated preferred stock that may be issued from time to time by the Company’s board of directors and (iv) effect a one for 19.86754 reverse stock split of the Company’s common stock outstanding immediately prior to the filing of the amended and restated certificate of incorporation. Private Placement of Common Stock On November 14, 2017, the Company entered into purchase agreements (collectively, the “Purchase Agreements”) with certain accredited institutional investors (collectively, the “Purchasers”), each with substantially similar terms and conditions. Pursuant to the Purchase Agreements, the Company agreed to issue and sell to the Purchasers an aggregate of 2,958,094 shares of unregistered common stock at a price per share of $6.085, for gross proceeds of $18,000 (the “Private Placement”). Each common share was issued with a detachable warrant to purchase one share of common stock at an exercise price of $6.085 per share, expiring seven years after the closing of the Purchase Agreements. The common shares issued in the Private Placement have the same rights and privileges as all other issued and outstanding common shares. As a result of the consummation of the February 2019 Public Offering, the exercise price of the 2017 Warrants automatically was adjusted pursuant to, and in accordance with, their terms, to $1.75 per share. The gross proceeds of $18,000 were first allocated to the fair value of the warrants of $12,335 with the remaining proceeds of $5,665 being allocated to the common stock. After giving effect to issuance costs related to the Private Placement, net proceeds were $17,250. If all of the Warrants are exercised in cash at the stated exercise price during the term, the Company will receive additional proceeds of approximately $18,000 and will issue an aggregate of 2,958,094 shares of common stock (the “Warrant Shares”). During the year ended December 31, 2018, there were 200,000 warrants exercised, resulting in gross proceeds to the Company of $1,217. The Company incurred $750 of issuance costs associated with the Private Placement which consisted of legal, consulting and regulatory fees. The costs were allocated between the issuance of the common stock and warrants on a pro rata basis with the allocation of the proceeds, with approximately 68% of the costs allocated to the warrants and approximately 32% allocated to the common stock. The issuance costs associated with the common stock totaled $236 and were recorded as a reduction to additional paid-in capital on the consolidated balance sheet. The issuance costs associated with the warrants totaled $514 and were recorded within interest expense on the consolidated statement of operations. HealthCare Ventures IX, L.P. and Eli Lilly and Company, each a holder of more than 5% of the Company’s outstanding common stock, also purchased common stock and warrants in the Private Placement. Each of HealthCare Ventures IX, L.P. and Eli Lilly and Company agreed to purchase the common stock and warrants on the same terms and conditions as the other Purchasers in the Private Placement. Three of the Company’s directors and executive officers are affiliated with HealthCare Ventures IX, L.P. and its affiliates. Pursuant to the terms of the Purchase Agreements, the Company was obligated to prepare and file with the SEC a registration statement on Form S-3 (the “Registration Statement”) to register for resale the shares and the Warrant Shares on or prior to the date 30 days following the closing of the Private Placement, and use its best commercially reasonable efforts, subject to receipt of necessary information from the Purchasers, to cause the SEC to declare the Registration Statement effective within 60 days following the closing of the Private Placement or, if the Registration Statement is selected for review by the SEC, within 90 days following the closing of the Private Placement. In order to comply with such obligation, the Company initially filed a registration statement for the resale of up to 3,734,914 shares of the shares and Warrant Shares issued in the Private Placement on December 8, 2017. Two of the Purchasers opted not to register their shares or Warrant Shares and therefore, such shares and Warrant Shares were excluded from the Registration Statement. The SEC declared this Registration Statement, as amended, effective on December 15, 2017. Public Offering of Common Stock On March 27, 2018, the Company completed a public offering whereby the Company issued 2,146,667 shares of its common stock at a price of $7.50 per share, which included 280,000 shares issued pursuant to the underwriters’ exercise of their option to purchase additional shares of common stock. The aggregate net proceeds received by the Company from the offering were approximately $14,796, net of underwriting discounts and commissions and estimated offering expenses payable by the Company.

Stock-Based Compensation

12 Months Ended

Dec. 31, 2018

Stock-Based Compensation

Stock-Based Compensation

10. Stock-Based Compensation

Equity Incentive Plans

In September 2012, the Company adopted the 2012 Equity Incentive Plan, as amended (the “Plan”), 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 amended and restated 2012 Equity Incentive Plan (the “2012 Plan”), which amended and restated the Plan and was effective in connection with the completion of the Company’s merger with Macrocure. As of December 31, 2018, there were 1,353,152 outstanding options issued under the 2012 Plan.

On January 20, 2017, the Company’s stockholders approved the 2016 Equity Incentive Plan (the “2016 Plan”), which was effective in connection with the completion of the Company’s merger with Macrocure. The number of shares of common stock issuable pursuant to outstanding awards granted under the 2016 Plan may not exceed the number that is equal to the sum of (i) 854,321 shares of common stock plus (ii) the number of shares of common stock (not to exceed 103,023 shares) subject to out-of-the-money options issued by Macrocure prior to the closing of the merger and assumed by the Company pursuant to the merger agreement upon consummation of the merger that expire unexercised. 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 December 31, 2018, there were 1,130,871 outstanding options issued under the 2016 Plan.

In connection with the merger with Macrocure in January 2017, the Company assumed the Macrocure 2013 Share Incentive Plan (the “2013 Plan”), the Macrocure 2008 Stock Option Plan (the “2008 Plan”) and all stock options outstanding under each of the 2013 Plan and the 2008 Plan immediately prior to the consummation of the merger. By virtue of the terms of the Merger Agreement and the 2013 Plan or the 2008 Plan, as applicable, each stock option outstanding immediately prior to the consummation of the merger was automatically converted into a stock option exercisable for a number of shares of the Company’s common stock calculated based on the exchange ratio and the exercise price per share of such outstanding stock option.

The Company could also make awards of restricted stock under the 2016 Plan. Restricted stock may be issued under the Equity Plan for such consideration, in cash, other property or services, or any combination thereof, as is determined by the Board of Directors. During the restriction period applicable to the shares of restricted stock, such shares shall be subject to limitations on transferability, subject to forfeiture or repurchase by the Company and/or subject to other terms and conditions. Upon lapse of such restrictions, the stock certificates representing shares of common stock shall be delivered to the grantee. As of December 31, 2018, there were 245,678 shares available for grant under the Company’s Equity Incentive Plans.

A summary of activity under the Company’s Equity Incentive Plans is as follows:


		Weighted
		Average		Weighted	Aggregate
		Exercise Price		Average Remaining	Intrinsic
	Options	Per Share		Life in Years	Value
Outstanding at December 31, 2016	53,228	$	4.93	7.00	$	213
Granted	2,220,858	$	12.51
Exercised	(3,506)	$	5.55
Forfeited	(12,959)	$	5.78
Outstanding at December 31, 2017	2,257,621	$	12.38	8.66	$	68
Granted	599,050	$	6.68
Exercised	(2,478)	$	5.56
Forfeited	(92,281)	$	7.89
Outstanding at December 31, 2018	2,761,912	$	11.30	8.01	$	—
Options exercisable at December 31, 2018	1,599,633	$	13.90	7.40	$	—
Options vested and expected to vest at December 31, 2018	2,761,912	$	11.30	8.01	$	—

During the years ended December 31, 2018 and 2017 the Company recognized $3,469 and $5,600 respectively, of stock-based compensation expense.

The assumptions that the Company used to determine the grant-date fair value of stock options granted to employees and directors were as follows, presented on a weighted average basis:


	Year Ended		Year Ended
	December 31,		December 31,
	2018		2017
Expected volatility	66.94	%	68.70	%
Weighted average risk-free interest rate	2.80	%	2.10	%
Expected dividend yield	0.00	%	0.00	%
Expected term (in years)	6.95		6.6

Stock options generally vest over a three or four year period, as determined by the Compensation Committee of the Board of Directors at the time of grant. The options expire ten years from the grant date. As of December 31, 2018, there was approximately $5,676 of unrecognized compensation cost related to non-vested stock options, which is expected to be recognized over a remaining weighted-average period of approximately 2.2 years.

Stock-based compensation expense was classified in the consolidated statements of operations as follows:


	Year Ended
	December 31,
	2018		2017
Research and development	$	625	$	1,834
General and administrative		2,844		3,766
Total	$	3,469	$	5,600

Income Taxes

12 Months Ended

Dec. 31, 2018

Income Taxes

Income Taxes

11. Income Taxes

The Company had federal, state and foreign net operating loss carryforwards of approximately $106,878, $87,868 and $69,941, respectively, as of December 31, 2018. The U.S. tax losses begin to expire in 2030. The foreign losses are primarily from Israel and have an indefinite carryforward. The Company’s federal net operating losses include $25,569 which can also be carried forward indefinitely.

The Company may be able to utilize its net operating loss carryforwards to reduce future federal and State income tax liabilities. However, these net operating losses are subject to various limitations under Internal Revenue Code section 382, which limit the use of net operating loss carryforwards to the extent there has been in ownership change of more than 50 percentage points. In addition, the net operating loss carryforwards are subject to examination by the taxing authorities and could be adjusted or disallowed due to such exams. Although the Company has not undergone an IRC section 382 analysis, it is possible that the utilization of the Company’s net operating loss carryforwards may be limited.

In addition, the Company has federal and state research and development tax credits of approximately $2,811 and $382, respectively, that begin expiring in 2030 for federal and state tax purposes.

There is no provision for income taxes in the United States or Israel, because the Company has historically incurred operating losses and maintains a full valuation allowance against its deferred tax assets in these jurisdictions. The deferred tax asset recorded in the consolidated balance sheets relates to the Company’s Australian operations.

Income (loss) before income taxes consisted of the following:


	Year Ended
	December 31,
	2018		2017
U.S.	$	(21,378)	$	(30,168)
Foreign		(1,740)		284
Loss before income taxes	$	(23,118)	$	(29,884)

A summary of the Company’s current and deferred expense for income tax is as follows:


	Year Ended
	December 31,
	2018		2017
Current expense (benefit):
Federal	$	—	$	—
State		—		—
Foreign		—		—
Total current expense (benefit):	$	—	$	—
Deferred expense (benefit):
Federal	$	—	$	—
State		—		—
Foreign		20		(157)
Total deferred expense (benefit):	$	20	$	(157)
Total income tax expense (benefit):	$	20	$	(157)

A reconciliation of the Company’s statutory income tax rate to the Company’s effective income tax rate is as follows:


	Year Ended
	December 31,
	2018		2017
Federal statutory income tax rate	21.00	%	34.00	%
State taxes, net of federal benefit	7.76	%	4.42	%
Permanent differences	2.38	%	(2.27)	%
Tax credits	6.94	%	3.45	%
Tax law change	0.00	%	(37.65)	%
Foreign rate differential	0.68	%	(0.02)	%
Valuation allowance	(38.26)	%	(3.11)	%
Other	(0.59)	%	1.68	%
	(0.09)	%	0.50	%

The significant components of the Company’s deferred tax assets as of December 31, 2018 and 2017 were as follows:


	Year Ended
	December 30,
	2018		2017
Federal net operating loss carryforwards	$	38,531	$	33,232
State net operating loss carryforwards		5,553		4,014
Stock Options		1,632		1,348
Federal research tax credits		2,811		1,799
State research tax credits		382		231
License fees		1,495		1,659
Accrued expenses		88		29
Other		149		182
Total deferred tax assets	$	50,641	$	42,494
Valuation allowance		(50,517)		(42,336)
Net deferred tax asset (liability)	$	124	$	158

As of December 31, 2018 and 2017, the Company had provided a full valuation allowance against its net deferred tax assets, except for its Australian deferred tax assets, because realization of any future tax benefit cannot be reasonably assured. The valuation allowance increased during the years ended December 31, 2018 and 2017, by $8,181 and $17,504, respectively.

During 2017, the Company recorded tax charges for the impact of the Tax Act effects using the current available information and technical guidance on the interpretations of the Tax Act. As permitted by SEC Staff Accounting Bulletin 118, Income Tax Accounting Implications of the Tax Cuts and Jobs Act, the Company recorded provisional estimates and have subsequently finalized the accounting analysis based on the guidance, interpretations, and data available as of December 31, 2018. Adjustments made in the fourth quarter of 2018 upon finalization of the accounting analysis were not material to the consolidated financial statements.

The Company follows the authoritative guidance on accounting for and disclosure of uncertainty in tax positions, which requires the Company to determine whether a tax position of the Company is more likely than not to be sustained upon examination, including resolution of any related appeals of litigation processes, based on the technical merits of the position. For tax positions meeting the more likely than not threshold, the tax amount recognized in the financial statements is reduced by the largest benefit that has a greater than 50% likelihood of being realized upon the ultimate settlement with the relevant taxing authority.

The Company files tax returns as prescribed by the tax laws of the jurisdictions in which it operates. In the normal course of business the Company is subject to examination by federal and state jurisdictions, where applicable. There are currently no pending tax examinations. The earliest tax years that may be subject to examination by jurisdiction are 2015 for both federal and state purposes. In addition, the NOL carryforwards are subject to examination by the taxing authority and could be adjusted or disallowed due to such exams. The Company’s policy is to record interest and penalties related to income taxes as part of the tax provision. There were no interest and penalties pertaining to uncertain tax positions for the years ended December 31, 2018 or 2017.

Net Loss Per Share

12 Months Ended

Dec. 31, 2018

Net Loss Per Share

Net Loss Per Share

12. Net Loss Per Share

Basic and diluted net loss per share for the years ended December 31, 2018 and 2017 was calculated as follows:


	Year Ended		Year Ended
	December 31,		December 31,
	2018		2017
Numerator:
Net loss	$	(23,138)	$	(29,727)
Accretion of preferred stock to redemption value		—		(244)
Net loss attributable to common stockholders for basic loss per share	$	(23,138)	$	(29,971)
Less change in fair value of warrant liability		7,284		473
Net loss attributable to common stockholders for diluted loss per share	$	(30,422)	$	(30,444)
Denominator:
Weighted average number of common shares outstanding-basic		14,144,287		9,161,844
Assumed conversion of dilutive securities:
Private Placement Warrants		268,408		26,743
Denominator for diluted loss per share-adjusted weighted average shares		14,412,695		9,188,587
Net loss per share attributable to common stockholders-basic	$	(1.64)	$	(3.27)
Net loss per share attributable to common stockholders-diluted	$	(2.11)	$	(3.31)

The Company’s potentially dilutive securities include stock options and warrants. These securities were excluded from the computations of diluted net loss per share for the years ended December 31, 2018 and 2017, as the effect would be to reduce the net loss per share. During the years ended December 31, 2018 and 2017, the outstanding warrants issued with the Private Placement is reflected in the diluted net loss per share computation by applying the treasury stock method. The following table includes the potential common shares, 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:


	Year Ended December 31,
	2018	2017
Options to purchase common stock	2,761,912	2,257,621
Warrants assumed from Macrocure	54,516	54,516
	2,816,428	2,312,137

Commitments and Contingencies

12 Months Ended

Dec. 31, 2018

Commitments and Contingencies

Commitments and Contingencies

13. Commitments and Contingencies

Lease Agreements—Effective January 1, 2017, the Company entered into an assignment agreement to assume an operating lease for its office space in Cambridge, Massachusetts. Annual rent under the lease, exclusive of operating expenses and real estate taxes, was $289 for the 12-month period ending July 31, 2017, $297 for the 12-month period ending July 31, 2018 and $305 for the 12-month period ending April 30, 2019. During the year ended December 31, 2018, the Company extended the term through April 30, 2022. Annual rent, exclusive of operating expenses and real estate taxes, for the 12-month periods ending April 30, 2020, April 30, 2021 and April 30, 2022, is $422, $429 and $437, respectively.

Effective July 15, 2018, the Company entered into an agreement to assume an operating lease for its research laboratory in Cambridge, Massachusetts. Annual rent under the lease, exclusive of operating expenses and real estate taxes, is $420. The lease expires on April 30, 2020.

Future minimum lease payments under these leases as of December 31, 2018 are as follows:


	Operating
Year Ending December 31,	Leases
2019	$	803
2020		532
2021		434
2022		146
	$	1,915

Manufacturing Agreements—The Company is party to manufacturing agreements with vendors to manufacture TRX518 and DKN‑01, our lead product candidates, for use in clinical trials. As of December 31, 2018, noncancelable commitments under these agreements totaled $154.

License and Service Agreements—On January 3, 2011, the Company entered into a license agreement with Eli Lilly and Company (“Lilly”) to grant a license to the Company for certain intellectual property rights relating to pharmaceutically active compounds that may be useful in the treatment of bone healing, cancer and, potentially, other medical conditions. The Company issued 9,000,000 shares of Series A Stock to Lilly in consideration for the grant of the license. As defined in the license agreement, the Company would be required to pay royalties to Lilly based upon a percentage in the low single digits of net sales of developed products, if and when achieved. However, there can be no assurance that clinical or commercialization success of developed products will occur, and no royalties have been paid or accrued through December 31, 2018.

License Agreement—On May 28, 2015, the Company entered into a license agreement with Lonza Sales AG (“Lonza”), pursuant to which Lonza granted the Company a world-wide, non-exclusive license for certain intellectual property relating to a gene expression system for manufacturing DKN‑01. As defined in the license agreement, the Company would be required to pay royalties to Lonza based on a percentage in the low single digits of net sales of DKN‑01, if and when achieved. However, there can be no assurance that clinical or commercialization success will occur, and no royalties have been paid or accrued through December 31, 2018.

Legal Proceedings—At each reporting date, the Company evaluates whether or not a potential loss amount or a potential range of loss is probable and reasonably estimable under the provisions of the authoritative guidance that addresses accounting for contingencies. The Company expenses as incurred the costs related to its legal proceedings.

A patent covering the TRX518 antibody and its uses in methods of inducing or enhancing an immune response in a subject was granted in 2013 to the Company by the European Patent Office (EPO). Three notices of opposition to this patent were filed: two by major pharmaceutical companies and a third by an individual, possibly on behalf of a major pharmaceutical company. At the conclusion of the opposition proceedings before the Opposition Division of the EPO, the Opposition Division issued a decision indicating that the Company’s patent was maintained with modified claims that differ from the claims as originally granted. These narrowed claims cover the TRX518 antibody and uses of the TRX518 antibody in methods of inducing or enhancing an immune response in a subject. The Company has filed an appeal of the decision of the Opposition Division seeking to obtain broader claims that more closely reflect the claims as granted in the patent. The EPO Board of Appeal has not yet scheduled a date for the appeal hearing.

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 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. A statement of our grounds of appeal is due on May 23, 2019. The EPO Board of Appeal has not yet scheduled a date for the appeal hearing.

Indemnification Agreements—In the ordinary course of business, the Company may provide indemnification of varying scope and terms to vendors, lessors, business partners and other parties with respect to certain matters including, but not limited to, losses arising out of breach of such agreements or from intellectual property infringement claims made by third parties. In addition, the Company has entered into indemnification agreements with members of its board of directors that will require the Company, among other things, to indemnify them against certain liabilities that may arise by reason of their status or service as directors or officers. The maximum potential amount of future payments the Company could be required to make under these indemnification agreements is, in many cases, unlimited. To date, the Company has not incurred any material costs as a result of such indemnifications. The Company is not aware of any claims under indemnification arrangements, and it has not accrued any liabilities related to such obligations in its consolidated financial statements as of December 31, 2018 and 2017.

Defined Contribution Plan	12 Months Ended
Defined Contribution Plan	Dec. 31, 2018
Defined Contribution Plan
Defined Contribution Plan	14. Defined Contribution Plan The Company has a 401(k) defined contribution plan (the “401(k) Plan”) for substantially all of its employees. Eligible employees may make pretax contributions to the 401(k) Plan up to statutory limits. The Company makes matching employee contributions in cash to the 401(k) Plan at a rate of 100% of the first 3% of earnings contributed and 50% of the next 2% of earnings contributed. Employees participating in the 401(k) Plan are fully vested in the Company matching contributions, and investments are directed by participants. The Company made matching contributions of $148 and $137 for the years ended December 31, 2018 and 2017, respectively.

Related Party Transactions	12 Months Ended
Related Party Transactions	Dec. 31, 2018
Related Party Transactions
Related Party Transactions	15. Related Party Transactions During the year ended December 31, 2017, the Company executed promissory notes with stockholders (See Note 6). The Company has a license agreement with a stockholder (See Note 13). On November 14, 2017, the Company entered into Purchase Agreements with certain Purchasers. Each of the Purchase Agreements was on terms and conditions substantially similar to each other Purchase Agreement and pursuant to such Purchase Agreements, the Company, in a private placement, agreed to issue and sell to the Purchasers an aggregate of 2,958,094 Shares of unregistered Common Stock, at a price per share of $6.085, each share issued with a Warrant to purchase one share of Common Stock at an exercise price of $6.085. HealthCare Ventures IX, L.P. and Eli Lilly and Company, each a more than 5% direct holder of the Company’s Common Stock, purchased Common Stock and Warrants in the Private Placement. Each of HealthCare Ventures IX, L.P. and Eli Lilly and Company agreed to purchase the Common Stock and Warrants on the same terms and conditions as the other Purchasers. Three of the Company’s directors and executive officers are affiliated with HealthCare Ventures IX, L.P. and its affiliates.

Subsequent Events	12 Months Ended
Subsequent Events	Dec. 31, 2018
Subsequent Events
Subsequent Events	16. Subsequent Events Public Offering of Common Stock On February 5, 2019, the Company completed a public offering whereby the Company issued 7,557,142 shares of its common stock at a price of $1.75 per share, which included 985,714 shares issued pursuant to the underwriters’ exercise of their option to purchase additional shares of common stock, each share issued with a warrant to purchase one share of common stock. Each warrant has an exercise price of $1.95 per share with an exercise period expiring seven years from the date of issuance. The aggregate net proceeds received by the Company from the offering were approximately $12,081, net of underwriting discounts and commissions and estimated offering expenses payable by the Company.

Summary of Significant Accounting Policies (Policies)

12 Months Ended

Dec. 31, 2018

Summary of Significant Accounting Policies

Principles of Consolidation

The accompanying 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

Cash and Cash Equivalents

The Company considers all highly liquid investments with maturities of three months or less when purchased to be cash equivalents.

Research and Development Expense

Research and development incentive income and receivable

The following table shows the change in the research and development incentive receivable from January 1, 2017 to December 31, 2018:


Balance at January 1, 2017	$	3,053
Australian research and development incentive income		1,715	(1)
Cash received for 2016 eligible expenses		(3,245)
Foreign currency translation		221
Balance at December 31, 2017		1,744
Australian research and development incentive income		756
Cash received for 2016 eligible overseas research and development expenses		(740)
Cash received for 2017 eligible expenses		(793)
Foreign currency translation		(131)
Balance at December 31, 2018	$	836

(1)

Concentration of Credit Risk

Income Taxes

Foreign Currency Translation

Property and Equipment

Impairment of Long-Lived Assets

Deferred Offering Costs

Other Assets

Fair Value of Financial Instruments

Level 1—Quoted prices in active markets for identical assets or liabilities.

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
December 31, 2018
Assets:
Cash equivalents	$	16,284	$	16,284	$	—	$	—
Total assets	$	16,284	$	16,284	$	—	$	—

Liabilities:
Warrant liability	$	3,448	$	—	$	—	$	3,448
Total liabilities	$	3,448	$	—	$	—	$	3,448

December 31, 2017
Assets:
Cash equivalents	$	25,737	$	25,737	$	—	$	—
Total assets	$	25,737	$	25,737	$	—	$	—

Liabilities:
Warrant liability	$	11,862	$	—	$	—	$	11,862
Total liabilities	$	11,862	$	—	$	—	$	11,862

A roll-forward of the recurring fair value measurements of the warrant liability categorized with Level 3 inputs are as follows (in thousands):


	Warrant
	Liability
Balance-January 1, 2017	$	—
Initial fair value		12,335
Change in fair value		(473)
Balance-December 31, 2017		11,862
Exercise of warrants		(1,130)
Change in Fair value		(7,284)
Balance-December 31, 2018	$	3,448

Segment Information

Patent Costs

Stock-Based Compensation

Net Loss per Share

Reclassification

Certain prior period amounts have been reclassified for consistency with the current period presentation. These reclassifications had no effect on previously reported results of operations.

Redeemable Convertible Preferred Stock

Warrant Liability

Recent Accounting Pronouncements

From time to time, new accounting pronouncements are issued by the Financial Accounting Standards Board, or FASB, and are early adopted by the Company or adopted as of the specified effective date.

The Company also considered the following recent accounting pronouncements which were not yet adopted as of December 31, 2018:

Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2018

Summary of Significant Accounting Policies

Schedule of change in the research and development incentive receivable


Balance at January 1, 2017	$	3,053
Australian research and development incentive income		1,715	(1)
Cash received for 2016 eligible expenses		(3,245)
Foreign currency translation		221
Balance at December 31, 2017		1,744
Australian research and development incentive income		756
Cash received for 2016 eligible overseas research and development expenses		(740)
Cash received for 2017 eligible expenses		(793)
Foreign currency translation		(131)
Balance at December 31, 2018	$	836

(1)

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
December 31, 2018
Assets:
Cash equivalents	$	16,284	$	16,284	$	—	$	—
Total assets	$	16,284	$	16,284	$	—	$	—

Liabilities:
Warrant liability	$	3,448	$	—	$	—	$	3,448
Total liabilities	$	3,448	$	—	$	—	$	3,448

December 31, 2017
Assets:
Cash equivalents	$	25,737	$	25,737	$	—	$	—
Total assets	$	25,737	$	25,737	$	—	$	—

Liabilities:
Warrant liability	$	11,862	$	—	$	—	$	11,862
Total liabilities	$	11,862	$	—	$	—	$	11,862

Schedule of the recurring fair value measurements of the warrant derivative liability categorized with Level 3 inputs

A roll-forward of the recurring fair value measurements of the warrant liability categorized with Level 3 inputs are as follows (in thousands):


	Warrant
	Liability
Balance-January 1, 2017	$	—
Initial fair value		12,335
Change in fair value		(473)
Balance-December 31, 2017		11,862
Exercise of warrants		(1,130)
Change in Fair value		(7,284)
Balance-December 31, 2018	$	3,448

Property and Equipment, Net (Tables)

12 Months Ended

Dec. 31, 2018

Property and Equipment, Net

Schedule of property and equipment, net


	December 31,
	2018		2017
Computer office equipment	$	51	$	51
Leasehold improvements		69		69
Lab equipment		58		58
Furnitures and fixtures		30		30
		208		208
Less: accumulated depreciation		(122)		(73)
Property and equipment, net	$	86	$	135

Accrued Expenses (Tables)

12 Months Ended

Dec. 31, 2018

Accrued Expenses

Schedule of accrued expenses


	December 31,
	2018		2017
Clinical trials	$	1,745	$	2,116
Professional fees		219		390
Payroll and related expenses		908		955
Accrued expenses	$	2,872	$	3,461

Warrants (Tables)

12 Months Ended

Dec. 31, 2018

Warrants

Schedule of warrants


December 31, 2018
	Number of Shares
Date Exercisable	Issuable	Exercise Price		Exercisable for	Classification
1/23/2017	54,516	$	0.01	Common Stock	Equity
11/14/2017	2,758,094		6.085	Common Stock	Liability
	2,812,610

- Definition

Tabular disclosure of warrants or rights issued. Warrants and rights outstanding are derivative securities that give the holder the right to purchase securities (usually equity) from the issuer at a specific price within a certain time frame. Warrants are often included in a new debt issue to entice investors by a higher return potential. The main difference between warrants and call options is that warrants are issued and guaranteed by the company, whereas options are exchange instruments and are not issued by the company. Also, the lifetime of a warrant is often measured in years, while the lifetime of a typical option is measured in months. Disclose the title of issue of securities called for by warrants and rights outstanding, the aggregate amount of securities called for by warrants and rights outstanding, the date from which the warrants or rights are exercisable, and the price at which the warrant or right is exercisable.

+ References + Details

Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2018

Stock-Based Compensation

Summary of stock option activity under the Company's Equity Incentive Plans


		Weighted
		Average		Weighted	Aggregate
		Exercise Price		Average Remaining	Intrinsic
	Options	Per Share		Life in Years	Value
Outstanding at December 31, 2016	53,228	$	4.93	7.00	$	213
Granted	2,220,858	$	12.51
Exercised	(3,506)	$	5.55
Forfeited	(12,959)	$	5.78
Outstanding at December 31, 2017	2,257,621	$	12.38	8.66	$	68
Granted	599,050	$	6.68
Exercised	(2,478)	$	5.56
Forfeited	(92,281)	$	7.89
Outstanding at December 31, 2018	2,761,912	$	11.30	8.01	$	—
Options exercisable at December 31, 2018	1,599,633	$	13.90	7.40	$	—
Options vested and expected to vest at December 31, 2018	2,761,912	$	11.30	8.01	$	—

Schedule of assumptions used to determine grant-date fair value of stock options


	Year Ended		Year Ended
	December 31,		December 31,
	2018		2017
Expected volatility	66.94	%	68.70	%
Weighted average risk-free interest rate	2.80	%	2.10	%
Expected dividend yield	0.00	%	0.00	%
Expected term (in years)	6.95		6.6

Schedule of stock-based compensation expense classified in the consolidated statements of operations


	Year Ended
	December 31,
	2018		2017
Research and development	$	625	$	1,834
General and administrative		2,844		3,766
Total	$	3,469	$	5,600

Income Taxes (Tables)

12 Months Ended

Dec. 31, 2018

Income Taxes

Schedule of income (loss) before income taxes


	Year Ended
	December 31,
	2018		2017
U.S.	$	(21,378)	$	(30,168)
Foreign		(1,740)		284
Loss before income taxes	$	(23,118)	$	(29,884)

Schedule of Company's current and deferred expense for income tax


	Year Ended
	December 31,
	2018		2017
Current expense (benefit):
Federal	$	—	$	—
State		—		—
Foreign		—		—
Total current expense (benefit):	$	—	$	—
Deferred expense (benefit):
Federal	$	—	$	—
State		—		—
Foreign		20		(157)
Total deferred expense (benefit):	$	20	$	(157)
Total income tax expense (benefit):	$	20	$	(157)

Schedule of reconciliation of the Company's statutory income tax rate to the Company's effective income tax rate


	Year Ended
	December 31,
	2018		2017
Federal statutory income tax rate	21.00	%	34.00	%
State taxes, net of federal benefit	7.76	%	4.42	%
Permanent differences	2.38	%	(2.27)	%
Tax credits	6.94	%	3.45	%
Tax law change	0.00	%	(37.65)	%
Foreign rate differential	0.68	%	(0.02)	%
Valuation allowance	(38.26)	%	(3.11)	%
Other	(0.59)	%	1.68	%
	(0.09)	%	0.50	%

Schedule of significant components of the Company's deferred tax assets


	Year Ended
	December 30,
	2018		2017
Federal net operating loss carryforwards	$	38,531	$	33,232
State net operating loss carryforwards		5,553		4,014
Stock Options		1,632		1,348
Federal research tax credits		2,811		1,799
State research tax credits		382		231
License fees		1,495		1,659
Accrued expenses		88		29
Other		149		182
Total deferred tax assets	$	50,641	$	42,494
Valuation allowance		(50,517)		(42,336)
Net deferred tax asset (liability)	$	124	$	158

Net Loss Per Share (Tables)

12 Months Ended

Dec. 31, 2018

Net Loss Per Share

Schedule of basic and diluted net loss per share


	Year Ended		Year Ended
	December 31,		December 31,
	2018		2017
Numerator:
Net loss	$	(23,138)	$	(29,727)
Accretion of preferred stock to redemption value		—		(244)
Net loss attributable to common stockholders for basic loss per share	$	(23,138)	$	(29,971)
Less change in fair value of warrant liability		7,284		473
Net loss attributable to common stockholders for diluted loss per share	$	(30,422)	$	(30,444)
Denominator:
Weighted average number of common shares outstanding-basic		14,144,287		9,161,844
Assumed conversion of dilutive securities:
Private Placement Warrants		268,408		26,743
Denominator for diluted loss per share-adjusted weighted average shares		14,412,695		9,188,587
Net loss per share attributable to common stockholders-basic	$	(1.64)	$	(3.27)
Net loss per share attributable to common stockholders-diluted	$	(2.11)	$	(3.31)

Schedule of potentially anti-dilutive securities excluded from calculation of diluted net loss per share


	Year Ended December 31,
	2018	2017
Options to purchase common stock	2,761,912	2,257,621
Warrants assumed from Macrocure	54,516	54,516
	2,816,428	2,312,137

Commitments and Contingencies - (Tables)

12 Months Ended

Dec. 31, 2018

Commitments and Contingencies

Schedule of future minimum lease payments under leases


	Operating
Year Ending December 31,	Leases
2019	$	803
2020		532
2021		434
2022		146
	$	1,915

Nature of Business, Basis of Presentation and Liquidity - Merger with Macrocure Ltd (Details) - Macrocure - USD ($) $ in Thousands	Jan. 23, 2017	Aug. 29, 2016
Merger with Macrocure Ltd
Purchase price		$ 10,000
Common Stock
Merger with Macrocure Ltd
Common stock shares issued	3,256,898
Percentage of outstanding ordinary shares acquired	100.00%

Nature of Business, Basis of Presentation and Liquidity - Reverse Stock Split (Details)	Jan. 20, 2017
Common Stock
Reverse Stock Split
Stock split ratio	0.05033

Nature of Business, Basis of Presentation and Liquidity - Liquidity (Details) - USD ($)			12 Months Ended
	Feb. 05, 2019	Mar. 27, 2018	Dec. 31, 2018	Dec. 31, 2017
Liquidity and going concern
Accumulated deficit			$ 153,535,000	$ 130,397,000
Net loss			23,138,000	29,727,000
Net cash used in operating activities			$ (26,033,000)	(22,137,000)
Number of Shares Issuable			2,812,610
Proceeds from issuance of common stock in connection with Subscription Agreement				10,000,000
Cash and cash equivalents			$ 16,284,000	25,737,000
Research and development incentive receivable			$ 836,000	$ 1,744,000
Minimum period to fund operating expense			12 months
Public Offering
Liquidity and going concern
Expected research and development tax incentive payments			$ 836,000
Common Stock \| Public Offering
Liquidity and going concern
Issuance of stock (in shares)		2,146,667	2,146,667
Price per common stock (in dollars per share)		$ 7.50
Proceeds from issuance of common stock in connection with Subscription Agreement		$ 14,796,000.000
Common Stock \| Public Offering \| Subsequent Events
Liquidity and going concern
Issuance of stock (in shares)	7,557,142
Number of Shares Issuable	7,557,142
Price per common stock (in dollars per share)	$ 1.75
Proceeds from issuance of common stock in connection with Subscription Agreement	$ 12,081,000
Common Stock \| Over-Allotment Option
Liquidity and going concern
Issuance of stock (in shares)	985,714	280,000
Number of Shares Issuable	985,714
Common Stock \| Over-Allotment Option \| Subsequent Events
Liquidity and going concern
Issuance of stock (in shares)	985,714

Summary of Significant Accounting Policies - Significant Accounting Policies (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
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	$ 1,744	$ 3,053
Australian research and development incentive income	756	1,715
Cash receiver for eligible expenses	(793)	(3,245)
Cash received for 2016 eligible overseas research and development expenses	(740)
Foreign currency translation	(131)	221
Balance at the end of the period	836	1,744	$ 3,053
Overseas research and development incentive income			$ 717
Uncertain Tax Positions
Uncertain tax positions	0	0
Interest and penalties pertaining to uncertain tax positions	0	0
Other Assets
Other assets	1,380	$ 1,111
Deferred issuance costs	$ 162
Computer equipment
Property and Equipment
Useful life (in years)	3 years
Lab equipment
Property and Equipment
Useful life (in years)	5 years
Office equipment
Property and Equipment
Useful life (in years)	5 years
Furnitures and fixtures
Property and Equipment
Useful life (in years)	5 years

Summary of Significant Accounting Policies - Fair Value of Financial Instruments (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Nov. 14, 2017
Assets:
Cash equivalents	$ 16,284	$ 25,737
Total assets	16,284	25,737
Liabilities:
Warrant liability	3,448	11,862	$ 12,335
Total liabilities	$ 3,448	11,862
Fair value measurements of the warrant liability
Dividend rate (as a percent)	0.00%
Level 1
Assets:
Cash equivalents	$ 16,284	25,737
Total assets	16,284	25,737
Level 1 \| Money market funds
Assets:
Cash equivalents	16,284	25,737
Level 3
Liabilities:
Warrant liability	3,448	11,862
Total liabilities	3,448	11,862
Recurring \| Warrant Liability
Fair value measurements of the warrant liability
Beginning Balance	11,862
Initial fair value		12,335
Change in fair value	(7,284)	(473)
Exercise of warrants	(1,130)
Ending Balance	$ 3,448	$ 11,862

Summary of Significant Accounting Policies - Net Loss per Share, Reclassification and Redeemable Convertible Preferred Stock (Details) - USD ($) $ in Thousands		12 Months Ended
	Jan. 20, 2017	Dec. 31, 2018
Maximum
Leases
Right-of-use assets and lease liabilities for operating leases		$ 2,000
Minimum
Leases
Right-of-use assets and lease liabilities for operating leases		$ 1,500
Conversion of preferred stock into common stock \| Common Stock
Redeemable Convertible Preferred Stock
Shares issued on conversion of preferred stock	3,174,523

Merger with Macrocure and Related Transactions - Merger with Macrocure Ltd. (Details) $ / shares in Units, $ in Thousands		12 Months Ended
	Jan. 23, 2017 USD ($) $ / shares shares	Dec. 31, 2017 USD ($)	Dec. 31, 2018 USD ($)
Merger with Macrocure
Value of net assets acquired in connection with merger with Macrocure, excluding cash		$ 96
Compensation cost related to Macrocure equity awards, not yet recognized			$ 5,676
Macrocure \| Common Stock
Merger with Macrocure
Common stock shares issued \| shares	3,256,898
Percentage of outstanding ordinary shares acquired	100.00%
Approximate number of the Company's shares issued for each share of Macrocure's ordinary shares	0.1815
Common share value (in dollars per share) \| $ / shares	$ 9.90
Final net cash calculation at closing	$ 21,875
Value of net assets acquired in connection with merger with Macrocure, excluding cash	$ 96
Compensation cost related to Macrocure equity awards, not yet recognized		280
One-time charge with the extension of the exercise periods		$ 504

Merger with Macrocure and Related Transactions - Recapitalization and Amendments to Certificate of Incorporation (Details)	Jan. 20, 2017 shares	Dec. 31, 2018 shares	Dec. 31, 2017 shares
Merger with Macrocure
Common stock, shares authorized		100,000,000	100,000,000
Common Stock
Merger with Macrocure
Common stock, shares authorized	100,000,000
Preferred stock, shares authorized	10,000,000
Stock split ratio	0.05033
Common Stock \| Conversion of preferred stock into common stock
Merger with Macrocure
Shares issued on conversion of preferred stock	3,174,523
Common Stock \| Conversion of notes payable - related party and accrued interest into common stock
Merger with Macrocure
Shares issued on conversion of notes payable and related accrued interest	1,950,768

Merger with Macrocure and Related Transactions - Subscription Agreement (Details) - Subscription Agreement - USD ($) $ / shares in Units, $ in Thousands		12 Months Ended
	Jan. 20, 2017	Dec. 31, 2017
Merger with Macrocure
Purchase price		$ 8,982
HCV IX
Merger with Macrocure
Issuance of stock (in shares)	1,010,225
Purchase price	$ 10,000
Price per common stock (in dollars per share)	$ 9.90

Merger with Macrocure and Related Transactions - Stock Option Grants (Details) - 2012 Plan - Macrocure	Jan. 20, 2017 item $ / shares shares
Merger with Macrocure
Number of executives \| item	3
Common Stock
Merger with Macrocure
Number of shares which can be purchased by each executive	330,303
Aggregate number of shares which can be purchased by executives	990,909
Exercise price \| $ / shares	$ 9.90
Vesting period subsequent to the first anniversary of the grant date	2 years
Common Stock \| Vesting on first anniversary
Merger with Macrocure
Options vesting on the first anniversary date of the grants (as a percent)	33.00%
Vesting period	1 year

Merger with Macrocure and Related Transactions - Royalty Agreement and Letter Agreement (Details)	Jan. 23, 2017
Royalty Vehicle
Merger with Macrocure
Collective beneficial ownership (as a percent)	100.00%
TRX 518 compound \| Royalty Agreement \| Royalty Vehicle
Merger with Macrocure
Royalties payable	5.00%
DKN-01 compound \| Royalty Agreement \| Royalty Vehicle
Merger with Macrocure
Royalties payable	2.00%

Property and Equipment, Net (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Property and Equipment, Net
Property and equipment, gross	$ 208	$ 208
Less: accumulated depreciation	(122)	(73)
Property and equipment, net	86	135
Depreciation expense	49	48
Computer office equipment
Property and Equipment, Net
Property and equipment, gross	51	51
Leasehold improvements
Property and Equipment, Net
Property and equipment, gross	69	69
Lab equipment
Property and Equipment, Net
Property and equipment, gross	58	58
Furnitures and fixtures
Property and Equipment, Net
Property and equipment, gross	$ 30	$ 30

Accrued Expenses (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Accrued Expenses
Clinical trials	$ 1,745	$ 2,116
Professional fees	219	390
Payroll and related expenses	908	955
Accrued expenses	$ 2,872	$ 3,461

Notes Payable-Related Party (Details) - USD ($) $ in Thousands			12 Months Ended
	Jan. 20, 2017	Jan. 13, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2014
Proceeds from promissory notes
Interest expense-related party			$ 121
Proceeds from promissory notes			750
Conversion of notes payable-related party and accrued interest into common stock			31,145
Common Stock
Proceeds from promissory notes
Conversion of notes payable-related party and accrued interest into common stock			2
Conversion of notes payable - related party and accrued interest into common stock \| Common Stock
Proceeds from promissory notes
Shares issued on conversion of notes payable and related accrued interest	1,950,768
Convertible Promissory notes \| Convertible promissory note executed with stockholder \| Stockholder
Proceeds from promissory notes
Note interest rate (as a percent)					8.00%
Promissory notes payable outstanding				$ 29,000
Accrued interest expense				$ 1,274
Interest expense-related party			$ 121
Proceeds from promissory notes		$ 750
Convertible Promissory notes \| Convertible promissory note executed with stockholder \| Stockholder \| Conversion of notes payable - related party and accrued interest into common stock
Proceeds from promissory notes
Conversion of notes payable-related party and accrued interest into common stock	$ 31,145

Warrants - (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Feb. 05, 2019	Nov. 14, 2017
Warrants
Number of Shares Issuable	2,812,610
Number of warrants exercised	200,000
Proceeds from exercise of warrants	$ 1,217
Fair value of warrant liability	3,448	$ 11,862		$ 12,335
Less change in fair value of warrant liability	7,284	473
Other income (expense)
Warrants
Less change in fair value of warrant liability	$ 7,284	$ 473
Common Stock \| Equity
Warrants
Number of Shares Issuable	54,516
Exercise price of warrant	$ 0.01
Common Stock \| Liability
Warrants
Number of Shares Issuable	2,758,094
Exercise price of warrant	$ 6.085
Common Stock \| Private Placement \| Warrants expires on 2024
Warrants
Number of Shares Issuable				2,958,094
Common Stock \| Public Offering \| Subsequent Events
Warrants
Number of Shares Issuable			7,557,142
Warrant Liability \| Subsequent Events
Warrants
Exercise price of warrant			$ 1.95
Warrant Liability \| Private Placement
Warrants
Exercise price of warrant				$ 6.085
Warrant Liability \| Private Placement \| Warrants expires on 2024
Warrants
Exercise price of warrant				$ 6.085
Warrant Liability \| Public Offering \| Subsequent Events
Warrants
Exercise price of warrant			$ 1.75

Preferred Stock - Activity (Details) - USD ($) $ in Thousands		12 Months Ended
	Jan. 20, 2017	Dec. 31, 2017
Preferred Stock
Accretion of preferred stock to redemption value		$ 244
Conversion of preferred stock into common stock \| Common Stock
Preferred Stock
Shares issued on conversion of preferred stock	3,174,523

Common Stock (Details) $ in Thousands		12 Months Ended
Common Stock (Details) $ in Thousands	Jan. 20, 2017 shares	Dec. 31, 2018 USD ($) Vote shares	Dec. 31, 2017 shares
Common stock, authorized shares		100,000,000	100,000,000
Common stock, outstanding shares		14,703,159	12,354,014
Number of votes each common share is entitled to \| Vote		1
Dividend declared \| $		$ 0
Common Stock
Common stock, authorized shares	100,000,000
Preferred stock, shares authorized	10,000,000
Stock split ratio	0.05033
Conversion of preferred stock into common stock \| Common Stock
Shares issued on conversion of preferred stock	3,174,523
Conversion of notes payable - related party and accrued interest into common stock \| Common Stock
Shares issued on conversion of notes payable and related accrued interest	1,950,768

Common Stock - Private Placement of Common Stock (Details) $ / shares in Units, $ in Thousands					12 Months Ended
	Feb. 05, 2019 $ / shares shares	Mar. 27, 2018 $ / shares shares	Dec. 08, 2017 shares	Nov. 14, 2017 USD ($) item $ / shares shares	Dec. 31, 2018 USD ($) shares	Dec. 31, 2017 USD ($) shares
Private Placement of Common Stock
Gross proceeds				$ 18,000		$ 18,000
Fair value of warrant liability				12,335	$ 3,448	11,862
Net proceeds from issuance of stock in private placement				17,250
Additional proceeds from exercise of warrants					$ 18,000
Additional shares issuable on exercise in cash of warrants \| shares					2,958,094,000
Number of warrants exercised \| shares					200,000
Proceeds from exercise of warrants					$ 1,217
Issuance costs associated with private placement					359	2,172
Common Stock
Private Placement of Common Stock
Remaining proceeds allocated to common stock				$ 5,665
Warrant Liability \| Subsequent Events
Private Placement of Common Stock
Exercise price of warrant \| $ / shares	$ 1.95
Private Placement
Private Placement of Common Stock
Number of warrants issued per common stock \| shares				1
Issuance costs associated with private placement				$ 750
Allocation of issuance cost to warrants (as a percentage)				68.00%
Allocation of issuance cost to common stock (as a percentage)				32.00%
Issuance costs associated with common stock				$ 236		$ 236
Number of days for registration				30 years
Number of days for declaration				60 years
Number of days for review				90 years
Number of purchasers not registered \| item				2
Private Placement \| HCV IX and Eli Lilly
Private Placement of Common Stock
Number of affiliated directors and executive officers \| item				3
Private Placement \| Minimum \| HCV IX and Eli Lilly
Private Placement of Common Stock
Direct Holding Common Stock Percentage				5.00%
Private Placement \| Maximum
Private Placement of Common Stock
Resale shares \| shares			3,734,914
Private Placement \| Other expense
Private Placement of Common Stock
Issuance costs associated with warrants				$ 514
Private Placement \| Common Stock
Private Placement of Common Stock
Issuance of stock (in shares) \| shares				2,958,094		2,958,094
Price per common stock (in dollars per share) \| $ / shares				$ 6.085
Private Placement \| Warrant Liability
Private Placement of Common Stock
Exercise price of warrant \| $ / shares				$ 6.085
Exercise expiring period				7 years
Public Offering
Private Placement of Common Stock
Issuance costs associated with common stock					$ 1,304
Public Offering \| Subsequent Events
Private Placement of Common Stock
Number of warrants issued per common stock \| shares	1
Public Offering \| Common Stock
Private Placement of Common Stock
Issuance of stock (in shares) \| shares		2,146,667			2,146,667
Price per common stock (in dollars per share) \| $ / shares		$ 7.50
Public Offering \| Common Stock \| Subsequent Events
Private Placement of Common Stock
Issuance of stock (in shares) \| shares	7,557,142
Price per common stock (in dollars per share) \| $ / shares	$ 1.75
Public Offering \| Warrant Liability \| Subsequent Events
Private Placement of Common Stock
Exercise price of warrant \| $ / shares	$ 1.75

Common Stock - Public Offering of Common Stock (Details) - USD ($)			12 Months Ended
	Feb. 05, 2019	Mar. 27, 2018	Dec. 31, 2018	Dec. 31, 2017
Proceeds from the issuance of common stock				$ 10,000,000
Common Stock \| Public Offering
Issuance of stock (in shares)		2,146,667	2,146,667
Price per common stock (in dollars per share)		$ 7.50
Proceeds from the issuance of common stock		$ 14,796,000.000
Common Stock \| Over-Allotment Option
Issuance of stock (in shares)	985,714	280,000

Stock-Based Compensation - Equity Incentive Plans (Details) - shares			12 Months Ended
	Dec. 31, 2018	Jan. 20, 2017	Dec. 31, 2018
Stock-Based Compensation
Number of options or stock awards available for grant under the equity incentive plans	245,678		245,678
2012 Plan
Stock-Based Compensation
Number of options issued under the plan	1,353,152
2016 Plan
Stock-Based Compensation
Number of options issued under the plan			1,130,871
2016 Plan \| Common Stock
Stock-Based Compensation
Annual increase in authorized shares (as a percent)		4.00%
2016 Plan \| Maximum \| Common Stock
Stock-Based Compensation
Shares issuable		854,321
Out-of-the-money options \| 2016 Plan \| Maximum \| Common Stock
Stock-Based Compensation
Additional shares issuable		103,023

Stock-Based Compensation - Stock options (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Options
Outstanding balance at the beginning of the period (in shares)	2,257,621	53,228
Granted (in shares)	599,050	2,220,858
Exercised (in shares)	(2,478)	(3,506)
Forfeited (in shares)	(92,281)	(12,959)
Outstanding balance at the end of the period (in shares)	2,761,912	2,257,621	53,228
Options exercisable at the end of the period (in shares)	1,599,633
Options vested and expected to vest at end of period (in shares)	2,761,912
Weighted Average Exercise Price Per Share
Outstanding balance at the beginning of the period (in dollars per share)	$ 12.38	$ 4.93
Granted (in dollars per share)	6.68	12.51
Exercised (in dollars per share)	5.56	5.55
Forfeited (in dollars per share)	7.89	5.78
Outstanding balance at the end of the period (in dollars per share)	11.30	$ 12.38	$ 4.93
Exercisable at the end of the period (in dollars per share)	13.90
Options vested and expected to vest at end of the period (in dollars per share)	$ 11.30
Weighted Average Remaining Life in Years
Outstanding balance	8 years 4 days	8 years 7 months 28 days	7 years
Options exercisable at end of period	7 years 4 months 24 days
Options vested and expected to vest at end of the period	8 years 4 days
Aggregate Intrinsic Value
Outstanding balance		$ 68	$ 213
Stock-based compensation expense	$ 3,469	5,600
Assumptions used to determine grant-date fair value
Expiration period	10 years
Compensation cost related to the non-vested awards not yet recognized	$ 5,676
Weighted average period for recognition of compensation cost	2 years 2 months 12 days
Research and development
Aggregate Intrinsic Value
Stock-based compensation expense	$ 625	1,834
General and administrative
Aggregate Intrinsic Value
Stock-based compensation expense	$ 2,844	$ 3,766
Maximum
Assumptions used to determine grant-date fair value
Vesting period	4 years
Minimum
Assumptions used to determine grant-date fair value
Vesting period	3 years
Options to purchase common stock \| Weighted average
Assumptions used to determine grant-date fair value
Expected Volatility	66.94%	68.70%
Weighted average risk-free interest rate	2.80%	2.10%
Expected dividend yield (as a percentage)	0.00%	0.00%
Expected term (in years)	6 years 11 months 12 days	6 years 7 months 6 days

Income Taxes - (Details) - USD ($) $ in Thousands	12 Months Ended
Income Taxes - (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Income (Loss) before income taxes
U.S.	$ (21,378)	$ (30,168)
Foreign	(1,740)	284
Loss before income taxes	$ (23,118)	$ (29,884)

Income Taxes - Operating Loss Carryforwards (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Operating Loss Carryforwards
Minimum ownership change allowed to avoid a limitation of use of net operating loss carryforwards (as a percent)	50.00%
Provision for income taxes	$ 20	$ (157)
Federal
Operating Loss Carryforwards
Operating loss carryforward	106,878
Research tax credits	2,811	1,799
State
Operating Loss Carryforwards
Operating loss carryforward	87,868
Research tax credits	382	$ 231
Foreign
Operating Loss Carryforwards
Operating loss carryforward	69,941
Indefinite federal net operating loss carryforward	$ 25,569

Income Taxes - Current and deferred expense for income tax (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Deferred expense (benefit):
Foreign	$ 20	$ (157)
Total deferred expense (benefit):	20	(157)
Total income tax expense (benefit):	$ 20	$ (157)

Income Taxes - Reconciliation of Statutory and Effective Tax Rates (Details)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Reconciliation of the statutory tax rate to the Company's effective tax rate
Federal statutory income tax rate	21.00%	34.00%
State taxes, net of federal benefit	7.76%	4.42%
Permanent differences	2.38%	(2.27%)
Tax credits	6.94%	3.45%
Tax law change	0.00%	(37.65%)
Foreign rate differential	0.68%	(0.02%)
Valuation allowance	(38.26%)	(3.11%)
Other	(0.59%)	1.68%
Effective income tax rate	(0.09%)	0.50%

Income Taxes - Components of Deferred Tax Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Deferred Tax Assets
Federal net operating loss carryforwards	$ 38,531	$ 33,232
State net operating loss carryforwards	5,553	4,014
Stock Options	1,632	1,348
License fees	1,495	1,659
Accrued expenses	88	29
Other	149	182
Total deferred tax assets	50,641	42,494
Valuation allowance	(50,517)	(42,336)
Net deferred tax assets (liability)	124	158
Federal
Deferred Tax Assets
Research tax credits	2,811	1,799
State
Deferred Tax Assets
Research tax credits	$ 382	$ 231

Income Taxes - Valuation Allowance and Tax Reforms (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Valuation Allowance
Increase in valuation allowance	$ 8,181	$ 17,504
Tax Reforms
Federal statutory income tax rate	21.00%	34.00%
Uncertain Tax Positions
Interest and penalties pertaining to uncertain tax positions	$ 0	$ 0

Net Loss Per Share - Basic and Diluted (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Numerator:
Net loss	$ (23,138)	$ (29,727)
Accretion of preferred stock to redemption value		(244)
Net loss attributable to common stockholders	(23,138)	(29,971)
Less change in fair value of warrant liability	7,284	473
Net loss attributable to common stockholders for diluted loss per share	$ (30,422)	$ (30,444)
Denominator:
Weighted average number of common shares outstanding - basic (in shares)	14,144,287	9,161,844
Assumed conversion of dilutive securities:
Private Placement Warrants (in shares)	268,408	26,743
Denominator for diluted loss per share - adjusted weighted average shares (in shares)	14,412,695	9,188,587
Net loss per share attributable to common stockholders - basic (in dollars per share)	$ (1.64)	$ (3.27)
Net loss per share attributable to common stockholders - diluted (in dollars per share)	$ (2.11)	$ (3.31)

Net Loss Per Share - Antidilutive (Details) - shares	12 Months Ended
Net Loss Per Share - Antidilutive (Details) - shares	Dec. 31, 2018	Dec. 31, 2017
Securities excluded from computation of diluted net loss per share
Anti-dilutive securities excluded from calculation of diluted net loss per share	2,816,428	2,312,137
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	2,761,912	2,257,621
Warrants assumed from Macrocure
Securities excluded from computation of diluted net loss per share
Anti-dilutive securities excluded from calculation of diluted net loss per share	54,516	54,516

Commitments and Contingencies - Lease Agreements (Details) - USD ($) $ in Thousands	Jul. 15, 2018	Jan. 01, 2017
Commitments and Contingencies
Annual rent	$ 420
Operating lease - 12-month period ending July 31, 2017
Commitments and Contingencies
Annual rent		$ 289
Operating lease - 12-month period ending July 31, 2018
Commitments and Contingencies
Annual rent		297
Operating lease - 12-month period ending April 30, 2019
Commitments and Contingencies
Annual rent		305
Operating lease - 12-month period ending April 30, 2020
Commitments and Contingencies
Annual rent		422
Operating lease - 12-month period ending April 30, 2021
Commitments and Contingencies
Annual rent		429
Operating lease - 12-month period ending April 30, 2022
Commitments and Contingencies
Annual rent		$ 437

Commitments and Contingencies - Future minimum lease payments (Details) $ in Thousands	Dec. 31, 2018 USD ($)
Future minimum lease payments
2019	$ 803
2020	532
2021	434
2022	146
Total	$ 1,915

Commitments and Contingencies - Manufacturing, License and Other Agreements (Details) - USD ($) $ in Thousands	Dec. 30, 2016	Dec. 31, 2018	Dec. 31, 2017
TRX518 and DKN-01
Commitments and Contingencies
Noncancelable commitments			$ 154
License and service agreements
Commitments and Contingencies
Paid or accrued royalties		$ 0
License and service agreements \| Preferred Class A
Commitments and Contingencies
Issuance of stock in consideration for license (in shares)	9,000,000
Licensing agreements
Commitments and Contingencies
Paid or accrued royalties		$ 0

Commitments and Contingencies - Legal Proceedings (Details)	1 Months Ended	12 Months Ended
	Mar. 31, 2017 item	Dec. 31, 2018 company individual item
TRX518
Loss Contingencies
Number of notices of opposition filed		3
Number of major companies that filed notices of opposition \| company		2
Number of individuals that filed notices of opposition \| individual		1
TRX518 and Chemotherapeutic
Loss Contingencies
Number of notices of opposition filed	10

Defined Contribution Plan (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Defined Contribution Plan
Contributions to the 401(k) Plan	$ 148	$ 137
Layering first
Defined Contribution Plan
Eligible Employees to contribute (as a percent)	3.00%
Company's match (as a percent)	100.00%
Layering second
Defined Contribution Plan
Eligible Employees to contribute (as a percent)	2.00%
Company's match (as a percent)	50.00%

Related Party Transactions (Details) - Private Placement		12 Months Ended
	Nov. 14, 2017 item $ / shares shares	Dec. 31, 2017 shares
Related Party Transactions
Number of warrants issued per common stock \| shares	1
HCV IX and Eli Lilly
Related Party Transactions
Number of affiliated directors and executive officers \| item	3
HCV IX and Eli Lilly \| Minimum
Related Party Transactions
Direct holding percentage	5.00%
Common Stock
Related Party Transactions
Issuance of stock (in shares) \| shares	2,958,094	2,958,094
Price per common stock (in dollars per share) \| $ / shares	$ 6.085
Warrant Liability
Related Party Transactions
Exercise price of warrant \| $ / shares	$ 6.085

Subsequent Events - Public Offering of Common Stock (Details) - USD ($)			12 Months Ended
	Feb. 05, 2019	Mar. 27, 2018	Dec. 31, 2018	Dec. 31, 2017
Subsequent Events
Proceeds from the issuance of common stock				$ 10,000,000
Warrant Liability \| Subsequent Events
Subsequent Events
Exercise price of warrant	$ 1.95
Warrant expiring period	7 years
Public Offering \| Subsequent Events
Subsequent Events
Number of warrants issued per common stock	1
Public Offering \| Common Stock
Subsequent Events
Issuance of stock (in shares)		2,146,667	2,146,667
Price per common stock (in dollars per share)		$ 7.50
Proceeds from the issuance of common stock		$ 14,796,000.000
Public Offering \| Common Stock \| Subsequent Events
Subsequent Events
Issuance of stock (in shares)	7,557,142
Price per common stock (in dollars per share)	$ 1.75
Proceeds from the issuance of common stock	$ 12,081,000
Public Offering \| Warrant Liability \| Subsequent Events
Subsequent Events
Exercise price of warrant	$ 1.75
Over-Allotment Option \| Common Stock
Subsequent Events
Issuance of stock (in shares)	985,714	280,000
Over-Allotment Option \| Common Stock \| Subsequent Events
Subsequent Events
Issuance of stock (in shares)	985,714