Document And Entity Information - USD ($)	12 Months Ended
Document And Entity Information - USD ($)	Dec. 31, 2018	Feb. 08, 2019	Jun. 30, 2018
Document and Entity Information [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2018
Document Fiscal Year Focus	2018
Document Fiscal Period Focus	FY
Entity Registrant Name	AVENUE THERAPEUTICS, INC.
Entity Central Index Key	0001644963
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 Public Float			$ 22,950,453
Trading Symbol	ATXI
Entity Common Stock, Shares Outstanding		16,502,310
Entity Shell Company	false
Entity Emerging Growth Company	true
Entity Ex Transition Period	true
Entity Small Business	true

BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Current Assets:
Cash and cash equivalents	$ 2,671	$ 11,782
Short-term investments	0	10,000
Deferred financing costs	1,702	0
Prepaid expenses and other current assets	152	388
Total Assets	4,525	22,170
Current Liabilities:
Accounts payable and accrued expenses	4,669	2,737
Accounts payable and accrued expenses - related party	487	53
Total current liabilities	5,156	2,790
Total Liabilities	5,156	2,790
Commitments and Contingencies
Stockholders' Equity (Deficit)
Common Stock ($0.0001 par value), 50,000,000 shares authorized Common shares; 10,667,714 and 10,265,083 shares issued and outstanding as of December 31, 2018 and 2017, respectively	1	1
Common stock issuable, 0 and 273,837 shares as of December 31, 2018 and 2017, respectively	0	1,103
Additional paid-in capital	41,577	38,937
Accumulated deficit	(42,209)	(20,661)
Total Stockholders' Equity (Deficit)	(631)	19,380
Total Liabilities and Stockholders' Equity (Deficit)	4,525	22,170
Series A Preferred Stock [Member]
Stockholders' Equity (Deficit)
Preferred Stock ($0.0001 par value), 2,000,000 shares authorized Class A Preferred Stock, 250,000 shares issued and outstanding as of December 31, 2018 and 2017, respectively	$ 0	$ 0

BALANCE SHEETS (Parenthetical) - $ / shares	Dec. 31, 2018	Dec. 31, 2017
Preferred Stock, Par or Stated Value Per Share	$ 0.0001	$ 0.0001
Preferred Stock, Shares Authorized	2,000,000	2,000,000
Common Stock, Par or Stated Value Per Share	$ 0.0001	$ 0.0001
Common Stock, Shares Authorized	50,000,000	50,000,000
Common Stock, Shares, Issued	10,667,714	10,265,083
Common Stock, Shares, Outstanding	10,667,714	10,265,083
Common Stock Shares issuable	0	273,837
Series A Preferred Stock [Member]
Preferred Stock, Shares Issued	250,000	250,000
Preferred Stock, Shares Outstanding	250,000	250,000

STATEMENTS OF OPERATIONS - USD ($) $ in Thousands	12 Months Ended
STATEMENTS OF OPERATIONS - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Operating expenses:
Research and development	$ 17,696	$ 6,698
Research and development - licenses acquired	0	1,103
General and administrative	4,120	3,620
Loss from operations	(21,816)	(11,421)
Interest income	(93)	(88)
Interest expense	0	294
Interest expense - related party	0	81
Change in fair value of convertible notes payable	0	99
Change in fair value of warrant liabilities	0	451
Other income	(175)	0
Net Loss	$ (21,548)	$ (12,258)
Net loss per common share outstanding, basic and diluted	$ (2.10)	$ (1.85)
Weighted average number of common shares outstanding, basic and diluted	10,239,169	6,634,937

STATEMENTS OF STOCKHOLDERS' EQUITY (DEFICIT) - USD ($) $ in Thousands	Total	Class A Preferred Shares	Common Shares	Common Shares Issuable	Additional paid-in capital	Accumulated deficit
Balance at Dec. 31, 2016	$ (8,248)	$ 0	$ 1	$ 49	$ 105	$ (8,403)
Balance (Shares) at Dec. 31, 2016		250,000	3,257,937	83,532
Issuance of common shares - Founders Agreement	948	$ 0	$ 0	$ (49)	997	0
Issuance of common shares - Founders Agreement (in shares)		0	241,657	(83,532)
Common shares issuable to Fortress - Founders	1,103	$ 0	$ 0	$ 1,103	0	0
Common shares issuable to Fortress - Founders (in shares)		0	0	273,837
Issuance of common shares, net of costs	34,235	$ 0	$ 0	$ 0	34,235	0
Issuance of common shares, net of costs (in shares)		0	6,325,000	0
Conversion of MSA fees into common shares	1,000	$ 0	$ 0	$ 0	1,000	0
Conversion of MSA fees into common shares (in shares)		0	166,666	0
Issuance of warrants under the NSC Note	750	$ 0	$ 0	$ 0	750
Exercise of warrants under the NSC Note	0	$ 0	$ 0	$ 0	0	0
Exercise of warrants under the NSC Note (in shares)		0	4,075	0
Conversion of notes payable	299	$ 0	$ 0	$ 0	299	0
Conversion of notes payable (in shares)		0	49,748	0
Change in fair value of convertible notes warrants	15	$ 0	$ 0	$ 0	15	0
Modification to interest on fortress note	300	0	0	0	300	0
Contribution of capital - extinguishment of Fortress compensation accrual	632	0	0	0	632	0
Share based compensation	604	$ 0	$ 0	$ 0	604	0
Share based compensation (in shares)		0	220,000	0
Net loss	(12,258)	$ 0	$ 0	$ 0	0	(12,258)
Balance at Dec. 31, 2017	19,380	$ 0	$ 1	$ 1,103	38,937	(20,661)
Balance (Shares) at Dec. 31, 2017		250,000	10,265,083	273,837
Issuance of common shares - Founders Agreement	0	$ 0	$ 0	$ (1,103)	1,103	0
Issuance of common shares - Founders Agreement (in shares)		0	273,837	(273,837)
Exercise of warrants under the NSC Note	0	$ 0	$ 0	$ 0	0	0
Exercise of warrants under the NSC Note (in shares)		0	20,816	0
Share based compensation	1,537	$ 0	$ 0	$ 0	1,537	0
Share based compensation (in shares)		0	107,978	0
Net loss	(21,548)	$ 0	$ 0	$ 0	0	(21,548)
Balance at Dec. 31, 2018	$ (631)	$ 0	$ 1	$ 0	$ 41,577	$ (42,209)
Balance (Shares) at Dec. 31, 2018		250,000	10,667,714	0

STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Cash flows from operating activities:
Net loss	$ (21,548)	$ (12,258)
Adjustments to reconcile net loss to net cash used in operating activities:
Share based compensation	1,537	604
Change in fair value of convertible notes payable	0	99
Change in fair value of warrant liabilities	0	451
Debt discount amortization	0	174
Issuance of common shares - Founders Agreement	0	948
Common shares issuable - Founders Agreement	0	1,103
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	236	(388)
Accounts payable and accrued expenses	1,125	2,231
Accounts payable and accrued expenses - related party	434	337
Interest payable	0	(57)
Accrued interest - related party	0	(46)
Net cash used in operating activities	(18,216)	(6,802)
Cash flows from investing activities:
Maturity (purchase) of Short-term investments (certificates of deposits)	10,000	(10,000)
Net cash provided by (used in) investing activities	10,000	(10,000)
Cash flows from financing activities:
Issuance of common shares	0	37,950
Offering costs	(895)	(3,715)
Repayment of NSC Note	0	(3,000)
Proceeds from notes payable - related party	0	637
Repayments of notes payable - related party	0	(3,485)
Net cash (used in) provided by financing activities	(895)	28,387
Net change in cash	(9,111)	11,585
Cash and cash equivalents, beginning of period	11,782	197
Cash and cash equivalents, end of period	2,671	11,782
Supplemental disclosure of cash flow information:
Cash paid for interest	0	303
Non-cash financing activities:
Unpaid deferred financing costs	807	0
Conversion of MSA fees into common shares	0	1,000
Issuance of warrants	0	750
Extinguishment of Fortress compensation accrual	0	632
Modification to interest on fortress note	0	300
Conversion of notes payable	0	200
Change in fair value of convertible notes warrants	$ 0	$ 15

Organization, Plan of Business Operations

12 Months Ended

Dec. 31, 2018

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block]

Note 1 — Organization, Plan of Business Operations

Avenue Therapeutics, Inc. (the “Company” or “Avenue”) was incorporated in Delaware on February 9, 2015, as a wholly owned subsidiary of Fortress Biotech, Inc. (“Fortress”), to develop and market pharmaceutical products for the acute care setting in the United States. The Company will focus on developing its product candidate, an intravenous (“IV”) formulation of tramadol HCI (“IV Tramadol”), for moderate to moderately severe post-operative pain.

Stock Purchase and Merger Agreement (the “SPMA”)

On November 12, 2018, the Company and InvaGen Pharmaceuticals Inc. (“InvaGen”), entered into definitive agreements with two closing stages for a proposed acquisition of the Company for a total aggregate consideration of $215.0 million. The SPMA was approved by a majority of the Company’s stockholders, including a majority of its non-affiliated

stockholders,

at its special shareholder meeting on February 6, 2019. On February 8, 2019, InvaGen acquired 5,833,333 shares of the Company’s common stock at $6.00

(“the Stock Purchase Transaction”)

per share for net proceeds of $31.5 million

after deducting commission fees and other offering costs

, representing a 33.3% stake in the Company’s capital stock on a fully diluted basis.

At the second stage closing, InvaGen will acquire the remaining shares of Avenue’s common stock, pursuant to a reverse triangular merger with Avenue remaining as the surviving entity, for up to $180.0

million in the aggregate (“the Merger Transaction”). The second stage closing is subject to the satisfaction of certain closing conditions, including conditions pertaining to U.S. Food and Drug Administration approval, labeling, scheduling and the absence of any Risk Evaluation and Mitigation Strategy (“REMS”) or similar restrictions in effect with respect to IV Tramadol, as well as the expiration of any waiting period applicable to the acquisition under the Hart-Scott-Rodino Antitrust Improvements Act of 1976, as amended.

Concurrently with the execution and delivery of the SPMA, the Company and InvaGen entered into a credit agreement (the “Credit Agreement”), pursuant to which InvaGen will provide initial financing to the Company in an amount of up to $3.0 million in the form of a line of credit, up to the closing of the Stock Purchase Transaction which occurred on February 8, 2019. Any amounts drawn on the line of credit will be deducted from the aggregate consideration payable to the Company pursuant to the Stock Purchase Transaction. As of December 31, 2018, no amounts were drawn on this line of credit. Subject to the terms and conditions described in the SPMA, the Buyer may also provide interim financing to the Company in an amount of up to $7.0 million during the time period between the Stock Purchase Transaction (which occurred on February 8, 2019) and the Merger Transaction. Any amounts drawn on the interim financing will be deducted from the aggregate consideration payable to Company stockholders by virtue of the Merger Transaction.

Concurrently with the execution and delivery of the Credit Agreement, Fortress and InvaGen entered into a guaranty (the “Guaranty”), pursuant to which Fortress guaranteed the full payment to InvaGen, when due, of all amounts of (x) all obligations of the Company to InvaGen under the Credit Agreement, whether for principal interest, fees, charges, expenses or otherwise, and (y) any and all costs and expenses incurred by InvaGen in enforcing any of its rights under the Guaranty.

Liquidity and Capital Resources

The Company has incurred substantial operating losses since its inception and expects to continue to incur significant operating losses for the foreseeable future as it executes on its product development plan and may never become profitable. As of December 31, 2018, the Company had an accumulated deficit of $42.2 million.

Significant Accounting Policies

12 Months Ended

Dec. 31, 2018

Accounting Policies [Abstract]

Significant Accounting Policies [Text Block]

Note 2 — Significant Accounting Policies

Basis of Presentation

The Company’s financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America (“U.S. GAAP”) and are stated in U.S. dollars. The Company has no subsidiaries.

The financial statements may not be indicative of future performance and may not reflect what their results of operations, financial position, and cash flows would have been had Avenue operated as an independent entity. Certain estimates, including allocations from Fortress, have been made to provide financial statements for stand-alone reporting purposes. Avenue became a stand-alone entity following the

Initial Public Offering (“IPO”)

on June 26, 2017. All inter-company transactions between Fortress and Avenue are classified as Accounts Payable and Accrued Expenses — Related Party in the financial statements. The Company believes that the assumptions underlying the financial statements are reasonable. The cost allocation methods used prior to the IPO in June 2017 applied to certain common costs include the following:

	•	Specific identification. Where the amounts were specifically identified to Avenue, they were classified accordingly.

	•	Reasonable allocation. Where the amounts were not clearly or specifically identified, management determined if a reasonable allocation method could be applied.

Reverse stock split

On June 26, 2017, the Company effected a 3.0-to-1.0 reverse stock split of Company's common stock. No fractional shares were issued in connection with the stock split. The par value and other terms of these classes of stock were not affected by the reverse stock split.

All share and per share amounts, including stock options, have been retroactively adjusted in these financial statements for all periods presented to reflect the 3.0-to-1.0 reverse stock split. Further, the fair value of stock issuances has been retroactively adjusted in these financial statements for all periods presented to reflect the 3.0-to-1.0 reverse stock split.

Use of Estimates

The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of expenses during the reporting period. Actual results could differ from those estimates.

Cash and Cash Equivalents

The Company considers all short-term investments with an original maturity of three months or less when purchased to be cash equivalents. Cash and cash equivalents at December 31, 2018 and at December 31, 2017 consisted of cash, money market funds and certificates of deposit in institutions in the United States. Balances at certain institutions have exceeded Federal Deposit Insurance Corporation (“FDIC”) insured limits and U.S. government agency securities.

Short-term Investments

The Company classifies its certificates of deposit as short-term investments in accordance with the Financial Accounting Standards Board ("FASB") ASC 320,

Investments - Debt and Equity Securities

. The Company considers all short-term investments with an original maturity in excess of three months

but less than a year

when

purchased to be short-term investments. There were no investments as of December 31, 2018. In July 2017 and in September 2017, the Company purchased $5.0 million of certificates of deposit with an original maturity of six months. At December 31, 2017, the Company had approximately $10.0 million in certificates of deposit with an original maturity of greater than three months. The Company reassesses the appropriateness of the classification of its investments at the end of each reporting period. The Company has determined that its certificates of deposits with an original maturity of six months should be classified as short-term investments as of December 31, 2017. This classification was based upon management’s determination that it has the positive intent and ability to hold the securities until their maturity dates, as its investments mature within one year and the underlying cash invested in these securities is not required for current operations.

Investments consist of short-term FDIC insured certificates of deposit carried at amortized cost using the effective interest method. The cost of the Company’s certificates of deposit approximated fair value.

Research and Development

Research and development costs are expensed as incurred. Advance payments for goods and services that will be used in future research and development activities are expensed when the activity has been performed or when the goods have been received rather than when the payment is made. Upfront and milestone payments due to third parties that perform research and development services on the Company’s behalf will be expensed as services are rendered or when the milestone is achieved.

Research and development costs primarily consist of personnel related expenses, including salaries, benefits, travel, and other related expenses, stock-based compensation, payments made to third parties for license and milestone costs related to in-licensed products and technology, payments made to third party contract research organizations for preclinical and clinical studies, investigative sites for clinical trials, consultants, the cost of acquiring and manufacturing clinical trial materials, costs associated with regulatory filings and patents, laboratory costs and other supplies.

Costs incurred in obtaining technology licenses are charged to research and development expense if the technology licensed has not reached commercial feasibility and has no alternative future use. The licenses purchased by the Company require substantial completion of research and development, regulatory and marketing approval efforts in order to reach commercial feasibility and have no alternative future use. Accordingly, the total purchase price for the licenses acquired are reflected as research and development — licenses acquired on the Company’s Statements of Operations.

Annual Stock Dividend

In September 2016, in connection with the Amended and Restated Articles of Incorporation, the Company issued 250,000 Class A preferred shares to Fortress. The Class A preferred shares entitled the holder to a stock dividend equal to 2.5% of the fully diluted outstanding equity of the Company (“The Annual Stock Dividend”) to be paid on February 17 of each year. On June 13, 2018, the Company’s Stockholders adopted an amendment to the Company’s Third Amended and Restated Certificate of Incorporation amending the payment date going forward to January 1 of each year. Concurrently with the execution and delivery of the SPMA, the Company, InvaGen and Fortress entered into a waiver agreement (“the Waiver Agreement”), pursuant to which, among other things, Fortress irrevocably waived its right to receive dividends of the Company’s common shares under the terms of the Class A Preferred Stock and any fees, payments, reimbursements or other distributions under a certain management services agreement between the Company and Fortress and the Founders Agreement (as defined in the SPMA), for the period November 12, 2018 to the termination of InvaGen’s rights under Section 4 of the Stockholders Agreement that was signed between the Company, certain stockholders of the Company, and InvaGen.

The Company recorded the Annual Stock Dividend due to Fortress as contingent consideration. Contingent consideration is recorded when probable and reasonably estimable. The Company’s future share prices cannot be estimated due to the nature of its assets and the Company’s stage of development. Due to these uncertainties, the Company concluded that it could not reasonably estimate the contingent consideration until shares were actually issued on February 17, 2018. Because the issuance of shares on February 17, 2018 occurred prior to the issuance of the December 31, 2017 financial statements, the Company recorded approximately $1.1 million in research and development - licenses acquired for the year ended December 31, 2017. Due to the Waiver Agreement, the Company recorded $0 in research and development - licenses acquired for the year ended December 31, 2018.

Fair Value Measurement

The Company follows accounting guidance on fair value measurements for financial assets and liabilities measured at fair value on a recurring basis. Under the accounting guidance, fair value is defined as an exit price, representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. As such, fair value is a market-based measurement that should be determined based on assumptions that market participants would use in pricing an asset or a liability.

The accounting guidance requires fair value measurements be classified and disclosed in one of the following three categories:

Level 1:

Quoted prices in active markets for identical assets or liabilities.

Level 2

: Observable inputs other than Level 1 prices, for similar assets or liabilities that are directly or indirectly observable in the marketplace.

Level 3

: Unobservable inputs which are supported by little or no market activity and that are financial instruments whose values are determined using pricing models, discounted cash flow methodologies, or similar techniques, as well as instruments for which the determination of fair value requires significant judgment or estimation.

The fair value hierarchy also requires an entity to maximize the use of observable inputs and minimize the use of unobservable inputs when measuring fair value. Assets and liabilities measured at fair value are classified in their entirety based on the lowest level of input that is significant to the fair value measurement. The Company’s assessment of the significance of a particular input to the fair value measurement in its entirety requires management to make judgments and consider factors specific to the asset or liability.

Stock-Based Compensation

The Company expenses stock-based compensation to employees and board members over the requisite service period based on the estimated grant-date fair value of the awards. Stock-based awards with graded-vesting schedules are recognized on a straight-line basis over the requisite service period for each separately vesting portion of the award. For stock-based compensation awards to non-employees, the Company measures the fair value of the non-employee awards at each reporting period prior to vesting and finally at the vesting date of the award. Changes in the estimated fair value of these non-employee awards are recognized as compensation expense in the period of change.

The assumptions used in calculating the fair value of stock-based awards represent management’s best estimates and involve inherent uncertainties and the application of management’s judgment.

Fair Value Option

As permitted under ASC 825,

Financial Instruments

, (“ASC 825”), the Company has elected the fair value option to account for its convertible notes that were issued during 2016. In accordance with ASC 825, the Company records these convertible notes at fair value with changes in fair value recorded in the Statement of Operations. As a result of applying the fair value option, direct costs and fees related to the convertible notes were recognized in earnings as incurred and were not deferred.

Valuation of Warrant Related to NSC Note

In accordance with ASC 815

Derivatives and Hedging

, the Company classified the fair value of the warrant (“Contingently Issuable Warrants”) that it may be obligated to issue to National Securities, Inc. (“NSC”), in connection with the transfer on October 31, 2015 of $3.0 million of indebtedness to NSC, as a derivative liability as there was a potential that the Company would not have a sufficient number of authorized common shares available to settle this instrument. The Company valued these Contingently Issuable Warrants using a Black-Scholes model and used estimates for an expected dividend yield, a risk-free interest rate, and expected volatility together with management’s estimate of the probability of issuance of the Contingently Issuable Warrants. At each reporting period, as long as the Contingently Issuable Warrants were potentially issuable and there was a potential for an insufficient number of authorized shares available to settle the Contingently Issuable Warrants, the Contingently Issuable Warrants had to be revalued and any difference from the previous valuation date would be recognized as a change in fair value in the Company’s statement of operations. On June 26, 2017, the warrants were issued (See Note 9).

Income Taxes

The Company accounts for income taxes under ASC 740,

Income Taxes

(“ASC 740”). ASC 740 requires the recognition of deferred tax assets and liabilities for both the expected impact of differences between the financial statement and tax basis of assets and liabilities and for the expected future tax benefit to be derived from tax loss and tax credit carry forwards. ASC 740 additionally requires a valuation allowance to be established when it is more likely than not that all or a portion of deferred tax assets will not be realized.

ASC 740 also clarifies the accounting for uncertainty in income taxes recognized in an enterprise’s financial statements and prescribes a recognition threshold and measurement process for financial statement recognition and measurement of a tax position taken or expected to be taken in a tax return. For those benefits to be recognized, a tax position must be more-likely-than-not to be sustained upon examination by taxing authorities. ASC 740 also provides guidance on de-recognition, classification, interest and penalties, accounting in interim period, disclosure and transition. Based on the Company’s evaluation, it has been concluded that there are no significant uncertain tax positions requiring recognition in the Company’s financial statements. Since the Company was incorporated on February 9, 2015, the 2015 through 2018 tax years are the only periods subject to examination upon filing of appropriate tax returns. The Company believes that its income tax positions and deductions would be sustained on audit and does not anticipate any adjustments that would result in a material change to its financial position.

The Company’s policy for recording interest and penalties associated with audits is to record such expense as a component of income tax expense. There were no amounts accrued for penalties or interest as of or during the years ended December 31, 2018 and 2017. Management is currently unaware of any issues under review that could result in significant payments, accruals or material deviations from its position.

Net loss per Share

Loss per share is computed by dividing net loss by the weighted-average number of common shares outstanding, excluding unvested restricted stock and stock options, during the period. Since dividends are declared paid and set aside among the holders of shares of common stock and Class A common stock pro-rata on an as-if-converted basis, the two-class method of computing net loss per share is not required.

The following table sets forth the potential common shares that could potentially dilute basic income per share in the future that were not included in the computation of diluted income (loss) per share because to do so would have been anti-dilutive for the periods presented:

	For the Years Ended
	December 31,		December 31,
	2018		2017
Restricted stock units/awards		1,104,643		714,999
Preferred shares		250,000		250,000
Options		20,000		20,000
Total potential dilutive effect		1,374,643		984,999

Comprehensive Loss

The Company has no components of other comprehensive loss, and therefore, comprehensive loss equals net loss.

Recently Adopted Accounting Standards

In January 2017, the FASB issued ASU No. 2017-01,

Business Combinations (Topic 805) Clarifying the Definition of a Business

(“ASU 2017-01”). The amendments in this ASU clarify the definition of a business with the objective of adding guidance to assist entities with evaluating whether transactions should be accounted for as acquisitions (or disposals) of assets or businesses. The definition of a business affects many areas of accounting including acquisitions, disposals, goodwill, and consolidation. The guidance is effective for annual periods beginning after December 15, 2017, including interim periods within those periods. The Company adopted ASU 2017-01 in the first quarter of 2018 and its adoption did not have a material impact on the Company’s 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. It is effective prospectively for the annual period ending December 31, 2018 and interim periods within that annual period. Early adoption is permitted. The Company early adopted ASU 2017-09 in the first quarter of 2018 and its adoption did not have a material impact on the Company’s financial statements.

In June 2018, the FASB issued ASU No. 2018-07,

Improvements to Nonemployee Share-Based Payment Accounting

, (“ASU 2018-07”) which simplifies the accounting for share-based payments granted to nonemployees for goods and services. Under the ASU, most of the guidance on such payments to nonemployees would be aligned with the requirements for share-based payments granted to employees. The changes take effect for public companies for fiscal years starting after December 15, 2018, including interim periods within that fiscal year. For all other entities, the amendments are effective for fiscal years beginning after December 15, 2019, and interim periods within fiscal years beginning after December 15, 2020. Early adoption is permitted, but no earlier than an entity’s adoption date of Topic 606. The Company adopted ASU 2018-07 in the first quarter of 2019 and its adoption did not have a material impact on the Company’s financial statements and related disclosures.

Allocation

12 Months Ended

Dec. 31, 2018

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

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

Note 3 — Allocation

The expense allocations to Avenue, which represent Lucy Lu’s executive compensation, have been paid by Fortress and allocated by the Company between Avenue and Fortress based on time spent on Avenue projects versus time spent on Fortress projects. The allocations were based on assumptions that management believes are reasonable; however, these allocations are not necessarily indicative of the costs and expenses that would have resulted if Avenue had been operating as a stand-alone entity. Since Lucy Lu became a full-time employee for Avenue in June 2017, the allocations ceased as her time spent was 100% devoted to Avenue. For the years ended December 31, 2018 and 2017, the allocated expenses related to Lucy Lu were approximately $0 and $0.2 million, respectively, and were recorded 50% to research and development and 50% to general and administration expenses. Upon the IPO, Fortress and Avenue agreed to extinguish the total amount accrued under these expense allocations. Therefore, the Company recorded the $0.6 million related to the allocation of Lucy Lu’s compensation as a contribution of capital on June 26, 2017.

License Agreement

12 Months Ended

Dec. 31, 2018

License Agreement [Abstract]

License Agreement Disclosure [Text Block]

Note 4 — License/Supplier Agreements

Effective as of February 17, 2015, Fortress transferred the Revogenex license and all other rights and obligations under the License Agreement to Avenue, pursuant to the terms of the Founders Agreement. In connection with the terms of the License Agreement, Fortress purchased an exclusive license to IV Tramadol for the U.S. market from Revogenex, a privately held company in Dublin, Ireland. Tramadol is a centrally acting synthetic opioid analgesic for moderate to moderately severe pain and is available as immediate release or extended-release tablets in the United States. Fortress made an upfront payment of $2.0 million to Revogenex upon execution of the exclusive license, and on June 17, 2015, Fortress paid an additional $1.0 million to Revogenex after receiving all the assets specified in the agreement. The $3.0 million cumulative payment was included in research and development-licenses acquired in the statements of operations. In addition, under the terms of the agreement, Revogenex is eligible to receive additional milestone payments totaling $4.0 million upon the achievement of certain development milestones, as well as royalty payments for sales of the product.

On October 29, 2018, the Company and Zaklady Farmaceutyczne Polpharma (“Polpharma”) extended the term of the supply agreement to eight years from the date of the launch of the product. In addition, under the terms of the amended agreement, Polpharma is eligible to receive a milestone payment totaling $2.0 million upon the achievement of a certain development milestone, as well as royalty payments for sales of the product.

Related Party Agreements

12 Months Ended

Dec. 31, 2018

Note 5 — Related Party Agreements

Founders Agreement and Management Services Agreement with Fortress

Fortress entered into a Founders Agreement with Avenue in February 2015, pursuant to which Fortress assigned to Avenue all of its rights and interest under Fortress’s license agreement with Revogenex for IV Tramadol (the “License Agreement”). As consideration for the Founders Agreement, Avenue assumed $3.0 million in debt (see Note 7) that Fortress accumulated to NSC for expenses and costs of forming Avenue and obtaining the IV Tramadol license, of which $3.0 million represents the acquisition of the License Agreement. As additional consideration for the transfer of rights under the Founders Agreement, Avenue shall also: (i) issue annually to Fortress, on the anniversary date of the Founders Agreement, shares of common stock equal to two and one half percent (2.5%) of the fully-diluted outstanding equity of Avenue at the time of issuance; (ii) pay an equity fee in shares of Avenue common stock, payable within five (5) business days of the closing of any equity or debt financing for Avenue or any of its respective subsidiaries that occurs after the effective date of the Founders Agreement and ending on the date when Fortress no longer has majority voting control in Avenue’s voting equity, equal to two and one half percent (2.5%) of the gross amount of any such equity or debt financing; and (iii) pay a cash fee equal to four and one half percent (4.5%) of Avenue’s annual net sales, payable on an annual basis, within ninety (90) days of the end of each calendar year. In the event of a change in control (as it is defined in the Founders Agreement), Fortress will be paid a one-time change in control fee equal to five (5x) times the product of (i) net sales for the twelve (12) months immediately preceding the change in control and (ii) four and one-half percent (4.5%). This additional consideration was waived on November 12, 2018 with the Waiver Agreement signed between Avenue, Fortress and InvaGen.

On September 13, 2016, the Company entered into an Amended and Restated the Founders Agreement (“A&R Founders Agreement”) with Fortress. The A&R Founders Agreement eliminated the Annual Equity Fee in connection with the original agreement and added a term of 15 years, which upon expiration automatically renews for successive one-year periods unless terminated by Fortress or a Change in Control occurs. Concurrently with the A&R Founders Agreement the Company entered into an Exchange Agreement whereby the Company exchanged Fortress’ 2.3 million Class A common shares for approximately 2.5 million common shares and 250,000 Class A Preferred shares (see Note 9).

On June 26, 2017, the Company issued 158,125 common shares to Fortress representing 2.5% of common shares issued in connection with the IPO (see Note 9). The Company recorded expense of approximately $0.9 million related to the financing fee in general and administrative expenses in the Statement of Operations for the year ended December 31, 2017.

Effective as of February 17, 2015, Fortress entered into a Management Services Agreement (the “MSA”) with Avenue and each of Avenue’s current directors and officers who are directors or officers of Fortress, excluding services provided by Dr. Lucy Lu, the Company’s current Chief Executive Officer as of June 26, 2017 and the former Chief Financial Officer of Fortress (resigned as of June 26, 2017), to provide services to Avenue pursuant to the terms of the MSA. Pursuant to the terms of the MSA, for a period of five (5) years, Fortress will render advisory and consulting services to Avenue. Services provided under the MSA may include, without limitation, (i) advice and assistance concerning any and all aspects of Avenue’s operations, clinical trials, financial planning and strategic transactions and financings and (ii) conducting relations on behalf of Avenue with accountants, attorneys, financial advisors and other professionals (collectively, the “Services”). Avenue is obligated to utilize clinical research services, medical education, communication and marketing services and investor relations/public relation services of companies or individuals designated by Fortress, provided those services are offered at market prices. However, Avenue is not obligated to take or act upon any advice rendered from Fortress and Fortress shall not be liable for any of Avenue’s actions or inactions based upon their advice. Fortress and its affiliates, including all members of Avenue’s Board of Directors, have been contractually exempt from fiduciary duties to Avenue relating to corporate opportunities. In consideration for the Services, Avenue will pay Fortress an annual consulting fee of $0.5 million (the “Annual Consulting Fee”), payable in advance in equal quarterly installments on the first business day of each calendar quarter in each year, provided, however, that such Annual Consulting Fee shall be increased to $1.0 million for each calendar year in which Avenue has net assets in excess of $100.0 million at the beginning of the calendar year.

On May 15, 2017, the Company and Fortress amended the MSA to allow for payment of the Annual Consulting Fee in the Company’s common stock in increments of $0.5 million, prior to the launch of the Company’s IPO (see Note 9). On June 26, 2017, the Company repaid $1.0 million of the outstanding 2015 and 2016 Annual Consulting fees by issuing 166,666 shares of the Company’s common stock at the offering price of $6.00 per share.

For the years ended December 31, 2018 and 2017, the Company had expenses related to the MSA of approximately $0.4 million and $0.5 million, respectively. Effective November 12, 2018, the MSA fee was waived with the Waiver Agreement signed between Avenue, Fortress and InvaGen.

Fortress Note

Effective March 15, 2015, the Company and Fortress entered into a future advance promissory note (the “Fortress Note”), in which Fortress agreed to provide a working capital line of credit until the Company has a third-party financing. Interest on the Fortress Note accrued at 8% per annum and shall be payable to Fortress on the day after the end of each calendar quarter following the first third-party financing. All principal and accrued interest under the Fortress Note is payable on demand following the first third-party financing. This Fortress Note can be pre-paid at any time in cash or through the assumption of Fortress’ indebtedness NSC or other similar indebtedness.

In May 2017, in anticipation of the Company’s IPO, the Company and Fortress amended the FBIO Note (the “FBIO Note Amendment”), to reduce interest on the FBIO Note from 8% to 2% from inception, effective the closing date of the Company’s IPO. Accordingly, on June 26, 2017, the interest rate was reduced and resulted in a reduction of interest of approximately $0.3 million ($0.4 million at 8% versus $0.1 million at 2%). In accordance with ASC 470-50,

Debt, Modifications and Extinguishments

, the Company determined that since the change in interest rate did not materially change the nature of the note, it was accounted for as a modification and recorded as a reduction in interest expense of $0.3 million in additional paid in capital on the Statement of Stockholders’ Equity (Deficit).

On July 25, 2017, the Company repaid the outstanding principal and interest balance of the Fortress Note of approximately $3.5 million and $0.1 million, respectively. For the years ended December 31, 2018 and 2017, the Company had interest expense related to the Fortress Note of approximately $0 and $74,000, respectively.

NSC Note and Financings

In September 2016, Fortress acquired through a tender offer 56.6% of National Holdings, Inc. (“National” or “NHLD”). The Company held an approximate $3.0 million NSC Note (“NSC Note”) (see Note 7) for which NSC, a subsidiary of National, received a 10% placement fee upon issuance of the Note to Fortress.

As of February 11, 2019, Fortress completed a two stage sale of its entire ownership in National and as such, National is no longer a related party.

On June 26, 2017, the Company completed an IPO and NSC acted as co-manager in this offering and earned commissions and fees of approximately $2.3 million. On July 5, 2017, the Company repaid the outstanding NSC Note of approximately $3.0 million and accrued interest of approximately $2,000.

On June 26, 2017, pursuant to the terms of the Company’s $3.0 million NSC Note, upon the closing of the Company’s IPO, the Company issued to National the Contingently Issuable Warrants for 125,000 common shares at par, relating to its aggregate gross proceeds from its third-party offerings exceeding five times the value of the debt. Upon the issuance of the Contingently Issuable Warrants, Fortress was removed as the guarantor on the note (see Note 7).

Accounts Payable and Accrued Expenses

12 Months Ended

Dec. 31, 2018

Payables and Accruals [Abstract]

Accounts Payable and Accrued Liabilities Disclosure [Text Block]

Note 6 — Accounts Payable and Accrued Expenses

Accounts payable, accrued expenses and other liabilities consisted of the following (in thousands):

	As of December 31,
	2018		2017
Accounts payable	$	3,089	$	1,545
Accrued employee compensation		463		215
Accrued contracted services and other		1,117		977
Accounts payable and accrued expenses	$	4,669	$	2,737

Notes Payable

12 Months Ended

Dec. 31, 2018

Debt Disclosure [Abstract]

Debt Disclosure [Text Block]

Note 7 — Notes Payable

NSC Note

In February 2015, Fortress closed a private placement of a promissory note for $10.0 million in favor of NSC Biotech Venture Fund I, LLC. Fortress used the proceeds from this promissory note to acquire medical technologies and products. The note matures in 36 months, provided that during the first 24 months Fortress can extend the maturity date by six months. No principal amount will be due for the first 24 months (or the first 30 months if the maturity date is extended). Thereafter, the note will be repaid at the rate of 1/12 of the principal amount per month for a period of 12 months. Interest on the note is 8% payable quarterly during the first 24 months (or the first 30 months if the note is extended) and monthly during the last 12 months. NSC acted as the sole placement agent for the this note. The NSC Note, was amended and restated on July 29, 2015, to provide that any time a Fortress Company receives from Fortress any proceeds from this note, Fortress may, in its sole discretion, cause the Fortress Company to issue to NSC Biotech Venture Fund I, LLC a new promissory note (the NSC Note) on identical terms as the original note (giving effect to the passage of time with respect to maturity). The NSC Note will equal the dollar amount of the Fortress Company’s share of the original note and reduce the Fortress’ obligations under the original note by such amount.

Fortress will guarantee the NSC Note until the Company either completes an initial public offering of its securities or raises sufficient equity capital so that it has cash equal to five times the NSC Note. If the Company has an initial public offering and raises sufficient equity capital so that it has cash equal to five times the amount of the portion of the proceeds of the NSC Note transferred to it, then NSC will receive a Contingently Issuable Warrant to purchase the Company’s stock equal to 25% of the outstanding note divided by the lowest price the Company sells its equity in its first third party financing. The warrants were issued on June 26, 2017 and have a term of 10 years and an exercise price equal to the par value of the Company’s common stock.

In January 2017, the Company notified NSC Biotech Venture Fund I, LLC, of its election to extend the maturity date to September 30, 2018.

As of December 31, 2016, the Company’s NSC Note totaled $3.0 million, with a debt discount related to the Company’s pro rata share of Fortress’ debt issuance costs of approximately $0.2 million. The effective interest rate of the NSC Note approximates 13.1%. The original fair value of the Contingently Issuable Warrants in connection with the NSC Note in the amount of approximately $0.1 million was recorded as a debt discount based on its fair value (see Note 9). The Contingently Issuable Warrants were recorded at fair value at each reporting period (see Note 10).

On June 26, 2017, pursuant to the terms of the Company’s $3.0 million NSC Note, upon the closing of the Company’s IPO, the Company issued to National warrants for 125,000 common shares at par with a fair value of $0.8 million, relating to its aggregate gross proceeds from its third-party offerings exceeding five times the value of the debt. Upon the issuance of the warrant, Fortress was removed as the guarantor on the note.

On July 5, 2017, the Company repaid the outstanding NSC Note of approximately $3.0 million and accrued interest of approximately $2,000. At December 31, 2017, the Company had $0 outstanding under its NSC Note.

For the years ended December 31, 2018 and 2017, the Company recorded interest expense of approximately $0 and $0.3 million, respectively.

The following table summarizes NSC Note activities as of December 31, 2018 (in thousands):

	Note Payable			Discount			Note Payable, Net
December 31, 2016 balance	$	3,000		$	(174	)	$	2,826
Repayments		(3,000	)		-			(3,000	)
Amortization of debt discount		-			174			174
December 31, 2017 balance	$	-		$	-		$	-
December 31, 2018 balance	$	-		$	-		$	-

Westpark Convertible Note

On December 30, 2016, Avenue held a closing of the sale of convertible promissory notes. Avenue sold three convertible promissory notes to investors for an aggregate of $0.2 million. The notes have an initial term of 18 months, which can be extended at the option of the holder, on one or more occasions, for up to 180 days and accrue simple interest at the rate of 5% per annum for the first 12 months and 8% per annum simple interest thereafter. The notes are guaranteed by Fortress. The outstanding principal and interest of the notes automatically converts into the type of equity securities sold by Avenue in the next sale of equity securities in which Avenue realizes aggregate gross cash proceeds of at least $10.0 million (before commissions or other expenses and excluding conversion of the notes) at a conversion price equal to the lesser of (a) the lowest price per share at which equity securities of Avenue are sold in such sale less a 33% discount and (b) a per share price based on a pre-offering valuation of $30.0 million divided by the number of common shares outstanding on a fully-diluted basis. The outstanding principal and interest of the notes may be converted at the option of the holder in any sale of equity securities that does not meet the $10.0 million threshold for automatic conversion using the same methodology. The notes also automatically convert upon a “Sale” of Avenue, defined as (a) a transaction or series of related transactions where one or more non-affiliates acquires (i) capital stock of Avenue or any surviving successor entity possessing the voting power to elect a majority of the board of directors or (ii) a majority of the outstanding capital stock of Avenue or the surviving successor entity (b) the sale, lease or other disposition of all or substantially all of Avenue’s assets or any other transaction resulting in substantially all of Avenue’s assets being converted into securities of another entity or cash. Upon a Sale of Avenue, the outstanding principal and interest of the notes automatically converts into common shares at a price equal to the lesser of (a) a discount to the price per share being paid in the Sale of Avenue equal to 33% or (b) the quotient resulting from dividing (x) $30.0 million by (y) the fully-diluted common stock of Avenue outstanding immediately prior to the Sale of Avenue (excluding the notes).

In the closing, Avenue realized net proceeds of $0.1 million after paying WestPark Capital, Inc., the placement agent, placement agent fees of $30,000 and escrow fees of $4,000 and paying approximately $14,000 in legal fees. Additionally, WestPark received a warrant (“Avenue Warrant”) to purchase the number of shares of Avenue’s common stock equal to $10,000 divided by the price per share at which any note sold to investors first converts into Avenue’s common stock. The Avenue Warrant has a ten-year term and has a per share exercise price equal to the price per share at which any note sold to investors first converts into Avenue’s common stock.

The fair value of these convertible notes amounted to $0.2 million.

Due to the complexity and number of embedded features within each convertible note, and as permitted under accounting guidance, the Company elected to account for the convertible notes and all the embedded features (collectively, the “hybrid instrument”) under the fair value option.

On June 26, 2017, in connection with the closing of the Company’s IPO, these convertible notes were converted into 49,748 shares of Avenue’s common stock.

Commitments and Contingencies

12 Months Ended

Dec. 31, 2018

Commitments and Contingencies Disclosure [Abstract]

Commitments and Contingencies Disclosure [Text Block]

Note 8 — Commitments and Contingencies

Leases

The Company is not a party to any leases for office space or equipment.

Litigation

The Company recognizes a liability for a contingency when it is probable that liability has been incurred and when the amount of loss can be reasonably estimated. When a range of probable loss can be estimated, the Company accrues the most likely amount of such loss, and if such amount is not determinable, then the Company accrues the minimum of the range of probable loss.

In connection with the SPMA, two putative class action lawsuits were filed in the United States District Court for the District of Delaware. The two lawsuits are captioned Bushansky v. Avenue Therapeutics, Inc. et al, Docket No. 1:19-cv-00085 (D. Del. Jan 15, 2019) and Krause v. Avenue Therapeutics, Inc. et al, Docket No. 1:19-cv-00107 (D. Del. Jan 17, 2019) (collectively, the “Merger Litigation”). The complaints, which were filed by purported Company stockholders, generally allege that the preliminary and definitive proxy statements that the Company filed with the SEC on December 11, 2018 and December 21, 2018, respectively, omitted certain material information in connection with the Stock Purchase Transaction and the Merger Transaction in violation of Sections 14(a) and 20(a) of the Securities Exchange Act of 1934, and SEC Rule 14a-9 thereunder. These complaints include demands for, among other things, an order enjoining defendants from closing the Stock Purchase Transaction and the Merger Transaction absent certain disclosures of information identified in the complaints.

The Company believes that the claims asserted in the Merger Litigation are without merit and that no supplemental disclosure was required under applicable law. However, in order to avoid the risk of the Merger Litigation delaying or adversely affecting the SPMA and to minimize the costs, risks and uncertainties inherent in litigation, and without admitting any liability or wrongdoing, the Company determined to voluntarily supplement the Proxy Statement it filed with the SEC on December 21, 2018. Nothing in the supplement to the proxy was deemed an admission of the legal necessity or materiality under applicable laws of any of the disclosures set forth within the supplement to the Proxy Statement. To the contrary, the Company specifically denied all allegations in the Merger Litigation that any additional disclosure was required.

Stockholders' Equity (Deficit)

12 Months Ended

Dec. 31, 2018

Equity [Abstract]

Stockholders' Equity Note Disclosure [Text Block]

Note 9 — Stockholders’ Equity (Deficit)

Class A Preferred Shares

Pursuant to the Company’s Third Amended and Restated Certificate of Incorporation, filed September 13, 2016, Class A Common Stock was eliminated and 2,000,000 shares of Preferred Stock were authorized, of which 250,000 have been designated as Class A Preferred Stock and the remainder are undesignated preferred stock. The Class A Preferred Stock, with a par value of $0.0001 per share, is identical to undesignated Common Stock other than as to voting rights, conversion rights, and the PIK Dividend right (as described below). The undesignated Preferred Stock may be issued from time to time in one or more series. The Company’s Board of Directors is authorized to determine or alter the dividend rights, dividend rate, conversion rights, voting rights, rights and terms of redemption (including sinking fund provisions, if any), the redemption price or prices, the liquidation preferences and other designations, powers, preferences and relative, participating, optional or other special rights, if any, and the qualifications, limitations and restrictions granted to or imposed upon any wholly unissued series of Preferred Stock, and to fix the number of shares of any series of Preferred Stock (but not below the number of shares of any such series then outstanding).

Pursuant to the Company’s Second Amended and Restated Certificate of Incorporation, the holders of the outstanding shares of Class A Preferred Stock shall receive on each February 17 (each a “PIK Dividend Payment Date”) after the original issuance date of the Class A Preferred Stock until the date all outstanding Class A Preferred Stock is converted into Common Stock or redeemed (and the purchase price is paid in full), pro rata per share dividends paid in additional fully paid and nonassessable shares of Common Stock (such dividend being herein called “PIK Dividends”) such that the aggregate number of shares of Common Stock issued pursuant to such PIK Dividend is equal to two and one-half percent (2.5%) of the Corporation’s fully-diluted outstanding capitalization on the date that is one (1) business day prior to any PIK Dividend Payment Date (“PIK Record Date”). In the event the Class A Preferred Stock converts into Common Stock, the holders shall receive all PIK Dividends accrued through the date of such conversion. No dividend or other distribution shall be paid, or declared and set apart for payment (other than dividends payable solely in capital stock on the capital stock of the Company) on the shares of Common Stock until all PIK Dividends on the Class A Preferred Stock shall have been paid or declared and set apart for payment. All dividends are non-cumulative. On June 13, 2018, the Company’s Stockholders adopted an amendment to the Company’s Third Amended and Restated Certificate of Incorporation amending the PIK Dividend Payment Date going forward to January 1 of each year. This PIK Dividend was waived in connection with the Waiver Agreement signed on November 12, 2018. (see Note 5).

On any matter presented to the stockholders of the Company for their action or consideration at any meeting of stockholders of the Company (or by written consent of stockholders in lieu of meeting), each holder of outstanding shares of Class A Preferred Stock shall be entitled to cast for each share of Class A Preferred Stock held by such holder as of the record date for determining stockholders entitled to vote on such matter, the number of votes that is equal to one and one-tenth (1.1) times a fraction, the numerator of which is the sum of (A) the number of shares of outstanding Common Stock and (B) the whole shares of Common Stock in to which the shares of outstanding Class A Common Stock and the Class A Preferred Stock are convertible, and the denominator of which is number of shares of outstanding Class A Preferred Stock (the “Class A Preferred Stock Ratio”). Thus, the Class A Preferred Stock will at all times constitute a voting majority.

Each share of Class A Preferred Stock is convertible, at the option of the holder, into one fully paid and nonassessable share of Common Stock (the “Conversion Ratio”), subject to certain adjustments. If the Company, at any time effects a subdivision or combination of the outstanding Common Stock (by any stock split, stock dividend, recapitalization, reverse stock split or otherwise), the applicable Conversion Ratio in effect immediately before that subdivision is proportionately decreased or increased, as applicable, so that the number of shares of Common Stock issuable on conversion of each share of Class A Preferred Stock shall be increased or decreased, a applicable, in proportion to such increase or decrease in the aggregate number of shares of Common Stock outstanding. Additionally, if any reorganization, recapitalization, reclassification, consolidation or merger involving the Company occurs in which the Common Stock (but not the Class A Preferred Stock) is converted into or exchanged for securities, cash or other property, then each share of Class A Preferred Stock becomes convertible into the kind and amount of securities, cash or other property which a holder of the number of shares of Common Stock of the Company issuable upon conversion of one share of the Class A Preferred Stock immediately prior to such reorganization, recapitalization, reclassification, consolidation or merger would have been entitled to receive pursuant to such transaction.

Common Stock

As of December 31, 2018, the Company’s authorized capital stock consists of 50,000,000 shares of common stock, with $0.0001 par value, and 2,000,000 shares of Preferred Stock, with $0.0001 par value, of which 250,000 have been designated as Class A Preferred Stock and the remainder are undesignated Preferred Stock.

Holders of our common stock are entitled to one vote for each share held on all matters submitted to a vote of stockholders and do not have cumulative voting rights. An election of directors by our stockholders shall be determined by a plurality of the votes cast by the stockholders entitled to vote on the election. Holders of common stock are entitled to receive proportionately any dividends as may be declared by our Board of Directors, subject to any preferential dividend rights of outstanding preferred stock.

In the event of our liquidation or dissolution, the holders of common stock are entitled to receive proportionately all assets available for distribution to stockholders after the payment of all debts and other liabilities and subject to the prior rights of any outstanding preferred stock. Holders of common stock have no preemptive, subscription, redemption or conversion rights. The rights, preferences and privileges of holders of common stock are subject to, and may be adversely affected by, the rights of the holders of shares of any series of preferred stock that we may designate and issue in the future.

On September 13, 2016, the Company entered into the A&R Founders Agreement with Fortress. The A&R Founders Agreement eliminated the Annual Equity Fee in connection with the original agreement and added a term of 15 years, which upon expiration automatically renews for successive one-year periods unless terminated by Fortress or a Change in Control occurs. Concurrently with the A&R Founders Agreement the Company entered into an Exchange Agreement whereby the Company exchanged Fortress’ 2.3 million Class A common shares for approximately 2.5 million common shares and 250,000 Class A Preferred shares.

Initial Public Offering

On June 26, 2017, the Company completed an IPO of its common stock, which resulted in the issuance of 6,325,000 shares of its common stock, inclusive of 825,000 shares which were subject to an underwriter over-allotment. The shares were issued at $6.00 per share, resulting in net proceeds of approximately $34.2 million after deducting underwriting discounts, and other offering costs.

In conjunction with the closing of the IPO, the Company issued warrants in connection with its NSC Debt and its Convertible Notes.

Awards to Fortress

Pursuant to the Company’s Third and Second Amended and Restated Certificates of Incorporation, on February 17, 2018 and 2017, the Company issued 273,837 and 83,532, respectively, shares of common stock to Fortress, which equaled to 2.5% of the fully diluted outstanding equity of Avenue at the time of issuance for the annual stock dividend. The Company recorded an expense of approximately $1.1 million and $49,000, in research and development licenses-acquired related to these stock grants during the years ended December 31, 2017 and 2016, respectively.

On June 26, 2017, pursuant to the terms of the Founders Agreement with Fortress, the Company issued to Fortress 158,125 shares of common stock at $6.00 per share, representing the 2.5% financing fee Fortress receives on third-party financings. The Company recorded expense of approximately $0.9 million related to the financing fee in general and administrative expenses in the Statement of Operations for the year ended December 31, 2017.

On June 26, 2017, the Company repaid $1.0 million of the outstanding 2015 and 2016 Annual Consulting fees by issuing 166,666 shares of the Company’s common stock at the offering price of $6.00 per share. The 2017 Annual Consulting fee of $0.5 million was paid in cash in the year ended December 31, 2017.

Equity Incentive Plan

The Company has in effect the 2015 Incentive Plan (“2015 Incentive Plan’). The 2015 Incentive Plan was adopted in January 2015 by our stockholders. Under the 2015 Incentive Plan, the compensation committee of the Company’s board of directors is authorized to grant stock-based awards to directors, officers, employees and consultants. The plan authorizes grants to issue up to 2,000,000 shares of authorized but unissued common stock and expires 10 years from adoption and limits the term of each option to no more than 10 years from the date of grant.

Total shares available for the issuance of stock-based awards under the Company’s 2015 Incentive Plan was 647,022 shares at December 31, 2018.

Restricted Stock Units and Restricted Stock Awards

The following table summarizes restricted stock unit and award activity for the year ended December 31, 2018:

	Number of Units and Awards			Weighted Average Grant Date Fair Value
Unvested balance at December 31, 2017		714,999		$	5.00
Granted		467,978		$	3.48
Vested		(78,334	)	$	2.05
Unvested balance at December 31, 2018		1,104,643		$	4.45

For the years ended December 31, 2018 and 2017 stock-based compensation expenses associated with the amortization of restricted stock units and restricted stock awards for employees and non-employees were approximately $1.5 million and $0.6 million, respectively.

For the years ended December 31, 2018, and 2017, the weighted average grant date fair value of restricted stock units and awards granted was $3.48 and $6.77, respectively. The total fair value of restricted stock units and awards that vested during the years ended December 31, 2018 and 2017 was $0.1 million and $33,000, respectively.

At December 31, 2018, the Company had unrecognized stock-based compensation expense related to restricted stock units and restricted stock awards of $3.3 million, which is expected to be recognized over the remaining weighted-average vesting period of 2.0 years.

On November 12, 2018, the Company and Dr. Lucy Lu entered into an amendment to the Executive Employment Agreement, dated June 10, 2015 (“the Employment Agreement”), pursuant to which the Dr. Lu. shall be vested in one hundred percent (100%) of all unvested equity rewards in the event of the termination of the Executive Employment Agreement upon her death, complete disability, termination without cause or resignation for good reason not in connection with a change of control (other than certain equity awards which may be granted following the SPMA). Pursuant to the amendment, the Executive’s separation benefits following her termination without cause or resignation for good reason in connection with a change of control (100% vesting) is subject to an additional condition that Dr. Lu has not entered into a new employment agreement with the Company’s acquirer or an affiliate thereof. Dr. Lu’s original Employment Agreement provided for accelerated vesting of only those unvested shares that would have vested in the upcoming year upon death or disability, termination without cause outside of a change in control, or resignation for good reason outside of a change in control. As this modification does not affect the fair value of the award, no adjustment to compensation cost is necessary. Any acceleration of vesting upon the events described above will result in a recognition of the remaining compensation cost associated with the award.

Stock Options

On August 15, 2017, 20,000 stock options were granted to a consultant under the 2015 Incentive Plan with a $6.29 exercise price and a five-year life. The stock options vest upon achievement of certain milestones based on the price of the Company’s stock in relation to the exercise price of $6.29. The stock options were valued using a Black-Scholes model with the following assumptions; volatility of 80%, risk free rate of 1.83% and effective life of 5 years. The fair value of each stock option was $1.85. The entire value of the stock option grant of $37,000 was expensed on the grant date in accordance with ASC 505

Equity-based Payments to Non-employees

as “no specific performance is required by the grantee to retain those equity instruments, then, because of the elimination of any obligation on the part of the counterparty to earn the equity instruments, a measurement date has been reached.”

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

	Stock Options		Weighted Average Exercise Price		Weighted Average Remaining Contractual Life (in years)
Outstanding, December 31, 2017		20,000	$	6.29		4.63
Granted		-		-		-
Outstanding, December 31, 2018		20,000	$	6.29		3.63

Stock Warrants

On June 26, 2017, sufficient equity capital was raised so that the Company had cash equal to five times the amount of the portion of the proceeds of the NSC Note transferred to it. As a result, the Company issued warrants for 125,000 common shares with an exercise price of par value and a ten-year term. As a result of this transaction, the Company recorded the fair value of the Contingently Issuable Warrants of approximately $0.8 million as an increase to additional paid in capital on the Statement of Stockholders’ Equity (Deficit).

On June 26, 2017, in connection with the automatic conversion of the WestPark Convertible Notes, which automatically converted upon the closing of the IPO, the Company issued 2,488 warrants at an exercise price of $4.02 and a ten-year term. Pursuant to the terms of the note agreement, the exercise price represents the price at which the notes converted, which is equal to a 33% discount to the IPO price of $6.00 per share.

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

	Warrants			Weighted Average Exercise Price		Aggregate Intrinsic Value (in thousands)
Outstanding, December 31, 2017		123,413		$	0.0811	$	438
Exercised		(20,816	)	$	0.0001		-
Outstanding, December 31, 2018		102,597		$	0.0976	$	544

Fair Value Measurement

12 Months Ended

Dec. 31, 2018

Fair Value Disclosures [Abstract]

Fair Value Disclosures [Text Block]

Note 10 — Fair Value Measurement

Financial instruments measured at fair value are classified in their entirety based on the lowest level of input that is significant to the fair value measurement. At December 31, 2018 and 2017, the warrant balance of $0 was classified as Level 3 instruments.

The following table sets forth the changes in the estimated fair value for the Company’s Level 3 classified derivative warrant liability (in thousands):

	NSC Contingently Issuable Warrants			Westpark Contingently Issuable Warrants			Total
Fair value, December 31, 2016	$	302		$	12		$	314
Change in fair value		448			3			451
Conversion into common shares		(750	)		-			(750	)
Change in fair value of convertible notes warrants		-			(15	)		(15	)
Fair value, December 31, 2017		-			-			-
Change in fair value		-			-			-
Fair value, December 31, 2018	$	-		$	-		$	-

On June 26, 2017, pursuant to the terms of the Company’s $3.0 million NSC Note, upon the closing of the Company’s IPO, the Company issued to National warrants for 125,000 common shares at par with a fair value of $0.8 million, relating to its aggregate gross proceeds from its third-party offerings exceeding five times the value of the debt. Upon the issuance of the warrant, Fortress was removed as the guarantor on the note (see Note 7).

Additionally, on June 26, 2017, the Company issued 2,488 warrants to purchase common shares of the Company at $4.02, to Westpark, in connection with their role as placement agent.

The following table sets forth the changes in the estimated fair value for our Level 3 classified convertible notes payable (in thousands):

	Westpark Convertible Notes
Fair value, December 31, 2016	$	200
Change in fair value		99
Conversion into common shares		(299	)
Fair value, December 31, 2017	$	-
Change in fair value		-
Fair value, December 31, 2018	$	-

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References + Details

Income Taxes

12 Months Ended

Dec. 31, 2018

Income Tax Disclosure [Abstract]

Income Tax Disclosure [Text Block]

Note 11 — Income Taxes

For financial reporting purposes, the Company calculated income tax provision and deferred income tax balances as if it was a separate entity and had filed its own separate tax return under Sub-Chapter C of the Internal Revenue Code.

A reconciliation of the statutory U.S. federal rate to the Company’s effective tax rate is as follows:

	For the years ended December 31,
	2018			2017
Statutory federal income tax rate		21	%		35	%
State taxes, net of federal tax benefit		9	%		8	%
Federal tax rate change		0	%		(20	)%
State tax rate change		0	%		1	%
Non-deductible items		0	%		(3	)%
Other		0	%		(1	)%
Credits		5	%		1	%
Change in valuation allowance		(35	)%		(21	)%
Income taxes provision (benefit)		0	%		0	%

The components of the net deferred tax asset as of December 31, 2018 and 2017 are the following (in thousands):

	As of December 31,
	2018			2017
Deferred tax assets:
Net operating loss carryovers	$	10,160		$	4,220
Stock compensation and other		658			70
Change in warrant liabilities		-			226
Amortization of license		1,006			1,064
Accruals and reserves		221			8
Tax credits		1,294			154
Total deferred tax assets		13,339			5,742
Less valuation allowance		(13,339	)		(5,742	)
Deferred tax assets, net of valuation allowance	$	-		$	-

The Company has determined, based upon available evidence, that it is more likely than not that the net deferred tax asset will not be realized and, accordingly, has provided a full valuation allowance against it. A valuation allowance of approximately $13.3 million and $5.7 million was recorded for the years ended December 31, 2018 and 2017, respectively.

On December 22, 2017, “H.R.1”, formerly known as the “Tax Cuts and Jobs Act,” was signed into law. Among other items, H.R.1 reduced the federal corporate tax rate to 21% from the existing maximum rate of 35%, effective January 1, 2018. As a result, the Company recorded a decrease related to its deferred tax assets and valuation allowance of $2.5 million, with a corresponding net adjustment to deferred income tax expense of zero for the year ended December 31, 2017.

As of December 31, 2018, the Company had federal and state net operating loss carryforwards of approximately $34.5 million and $43.1 million, respectively. The federal and state net operating loss carryforwards will begin to expire, if not utilized, by 2035 and 2035, respectively. The Company has $1.3 million of research and development credit carryforwards, which will begin to expire, if not utilized, in 2035. Utilization of the net operating loss and credit carryforwards may be subject to an annual limitation due to the ownership change limitations provided by Section 382 of the Internal Revenue Code of 1986 (“IRC”), as amended and similar state provisions. Certain tax attributes are subject to an annual limitation as a result of the Company’s June 2017 initial public offering, which constitutes an ownership change under Section 382. Certain tax attributes may be subject to an annual limitation as a result of the SPMA with InvaGen, which could constitute an ownership change under Section 382.

There are no significant matters determined to be unrecognized tax benefits taken or expected to be taken in a tax return, in accordance with ASC 740 “Income Taxes” (“ASC 740”), which clarifies the accounting for uncertainty in income taxes recognized in the financial statements, that have been recorded on the Company’s financial statements for the periods ended December 31, 2018 and 2017. The Company does not anticipate a material change to unrecognized tax benefits in the next twelve months.

Additionally, ASC 740 provides guidance on the recognition of interest and penalties related to income taxes. There were no interest or penalties related to income taxes that have been accrued or recognized as of and for the periods ended December 31, 2018 and 2017.

The federal and state tax returns for the period ended December 31, 2015 and the years ended December 31, 2016, 2017, and 2018 are currently open for examination under the applicable federal and state income tax statues of limitations.

Subsequent Events

12 Months Ended

Dec. 31, 2018

Subsequent Events [Abstract]

Subsequent Events [Text Block]

Note 12 – Subsequent Events

Litigation

In connection with the SPMA, two putative class action lawsuits were filed in the United States District Court for the District of Delaware. The two lawsuits are captioned

Bushansky v. Avenue Therapeutics, Inc. et al, Docket No. 1:19-cv-00085 (D. Del. Jan 15, 2019)

and

Krause v. Avenue Therapeutics, Inc. et al, Docket No. 1:19-cv-00107 (D. Del. Jan 17, 2019)

(collectively, the “

Merger Litigation

”). The complaints, which were filed by purported Company stockholders, generally allege that the preliminary and definitive proxy statements that the Company filed with the SEC on December 11, 2018 and December 21, 2018, respectively, omitted certain material information in connection with the Stock Purchase Transaction and the Merger Transaction in violation of Sections 14(a) and 20(a) of the Securities Exchange Act of 1934, and SEC Rule 14a-9 thereunder. These complaints include demands for, among other things, an order enjoining defendants from closing the Stock Purchase Transaction and the Merger Transaction absent certain disclosures of information identified in the complaints.

The Company believes that the claims asserted in the Merger Litigation are without merit and that no supplemental disclosure was required under applicable law. However, in order to avoid the risk of the Merger Litigation delaying or adversely affecting the SPMA and to minimize the costs, risks and uncertainties inherent in litigation, and without admitting any liability or wrongdoing, the Company determined to voluntarily supplement the Proxy Statement it filed with the SEC on December 21, 2018. Nothing in the supplement to the proxy was deemed an admission of the legal necessity or materiality under applicable laws of any of the disclosures set forth within the supplement to the Proxy Statement. To the contrary, the Company specifically denied all allegations in the Merger Litigation that any additional disclosure was required.

SPMA

The SPMA was approved by a majority of the Company’s stockholders, including a majority of its non-affiliated stockholders, at its special shareholder meeting on February 6, 2019. On February 8, 2019, InvaGen acquired 5,833,333 shares of the Company’s common stock at $6.00 per share for net proceeds of $31.5 million

after deducting commission fees and other offering costs

, representing a 33.3% stake in the Company’s capital stock on a fully diluted basis.

Significant Accounting Policies (Policies)

12 Months Ended

Dec. 31, 2018

Accounting Policies [Abstract]

Basis of Accounting, Policy [Policy Text Block]

Basis of Presentation

The Company’s financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America (“U.S. GAAP”) and are stated in U.S. dollars. The Company has no subsidiaries.

The financial statements may not be indicative of future performance and may not reflect what their results of operations, financial position, and cash flows would have been had Avenue operated as an independent entity. Certain estimates, including allocations from Fortress, have been made to provide financial statements for stand-alone reporting purposes. Avenue became a stand-alone entity following the

Initial Public Offering (“IPO”)

on June 26, 2017. All inter-company transactions between Fortress and Avenue are classified as Accounts Payable and Accrued Expenses — Related Party in the financial statements. The Company believes that the assumptions underlying the financial statements are reasonable. The cost allocation methods used prior to the IPO in June 2017 applied to certain common costs include the following:

	•	Specific identification. Where the amounts were specifically identified to Avenue, they were classified accordingly.

	•	Reasonable allocation. Where the amounts were not clearly or specifically identified, management determined if a reasonable allocation method could be applied.

Reverse stock split

On June 26, 2017, the Company effected a 3.0-to-1.0 reverse stock split of Company's common stock. No fractional shares were issued in connection with the stock split. The par value and other terms of these classes of stock were not affected by the reverse stock split.

All share and per share amounts, including stock options, have been retroactively adjusted in these financial statements for all periods presented to reflect the 3.0-to-1.0 reverse stock split. Further, the fair value of stock issuances has been retroactively adjusted in these financial statements for all periods presented to reflect the 3.0-to-1.0 reverse stock split.

Use of Estimates, Policy [Policy Text Block]

Use of Estimates

The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of expenses during the reporting period. Actual results could differ from those estimates.

Cash and Cash Equivalents, Policy [Policy Text Block]

Cash and Cash Equivalents

The Company considers all short-term investments with an original maturity of three months or less when purchased to be cash equivalents. Cash and cash equivalents at December 31, 2018 and at December 31, 2017 consisted of cash, money market funds and certificates of deposit in institutions in the United States. Balances at certain institutions have exceeded Federal Deposit Insurance Corporation (“FDIC”) insured limits and U.S. government agency securities.

Investment, Policy [Policy Text Block]

Short-term Investments

The Company classifies its certificates of deposit as short-term investments in accordance with the Financial Accounting Standards Board ("FASB") ASC 320,

Investments - Debt and Equity Securities

. The Company considers all short-term investments with an original maturity in excess of three months

but less than a year

when

purchased to be short-term investments. There were no investments as of December 31, 2018. In July 2017 and in September 2017, the Company purchased $5.0 million of certificates of deposit with an original maturity of six months. At December 31, 2017, the Company had approximately $10.0 million in certificates of deposit with an original maturity of greater than three months. The Company reassesses the appropriateness of the classification of its investments at the end of each reporting period. The Company has determined that its certificates of deposits with an original maturity of six months should be classified as short-term investments as of December 31, 2017. This classification was based upon management’s determination that it has the positive intent and ability to hold the securities until their maturity dates, as its investments mature within one year and the underlying cash invested in these securities is not required for current operations.

Investments consist of short-term FDIC insured certificates of deposit carried at amortized cost using the effective interest method. The cost of the Company’s certificates of deposit approximated fair value.

Research and Development Expense, Policy [Policy Text Block]

Research and Development

Research and development costs are expensed as incurred. Advance payments for goods and services that will be used in future research and development activities are expensed when the activity has been performed or when the goods have been received rather than when the payment is made. Upfront and milestone payments due to third parties that perform research and development services on the Company’s behalf will be expensed as services are rendered or when the milestone is achieved.

Research and development costs primarily consist of personnel related expenses, including salaries, benefits, travel, and other related expenses, stock-based compensation, payments made to third parties for license and milestone costs related to in-licensed products and technology, payments made to third party contract research organizations for preclinical and clinical studies, investigative sites for clinical trials, consultants, the cost of acquiring and manufacturing clinical trial materials, costs associated with regulatory filings and patents, laboratory costs and other supplies.

Costs incurred in obtaining technology licenses are charged to research and development expense if the technology licensed has not reached commercial feasibility and has no alternative future use. The licenses purchased by the Company require substantial completion of research and development, regulatory and marketing approval efforts in order to reach commercial feasibility and have no alternative future use. Accordingly, the total purchase price for the licenses acquired are reflected as research and development — licenses acquired on the Company’s Statements of Operations.

Stockholders' Equity, Policy [Policy Text Block]

Annual Stock Dividend

In September 2016, in connection with the Amended and Restated Articles of Incorporation, the Company issued 250,000 Class A preferred shares to Fortress. The Class A preferred shares entitled the holder to a stock dividend equal to 2.5% of the fully diluted outstanding equity of the Company (“The Annual Stock Dividend”) to be paid on February 17 of each year. On June 13, 2018, the Company’s Stockholders adopted an amendment to the Company’s Third Amended and Restated Certificate of Incorporation amending the payment date going forward to January 1 of each year. Concurrently with the execution and delivery of the SPMA, the Company, InvaGen and Fortress entered into a waiver agreement (“the Waiver Agreement”), pursuant to which, among other things, Fortress irrevocably waived its right to receive dividends of the Company’s common shares under the terms of the Class A Preferred Stock and any fees, payments, reimbursements or other distributions under a certain management services agreement between the Company and Fortress and the Founders Agreement (as defined in the SPMA), for the period November 12, 2018 to the termination of InvaGen’s rights under Section 4 of the Stockholders Agreement that was signed between the Company, certain stockholders of the Company, and InvaGen.

The Company recorded the Annual Stock Dividend due to Fortress as contingent consideration. Contingent consideration is recorded when probable and reasonably estimable. The Company’s future share prices cannot be estimated due to the nature of its assets and the Company’s stage of development. Due to these uncertainties, the Company concluded that it could not reasonably estimate the contingent consideration until shares were actually issued on February 17, 2018. Because the issuance of shares on February 17, 2018 occurred prior to the issuance of the December 31, 2017 financial statements, the Company recorded approximately $1.1 million in research and development - licenses acquired for the year ended December 31, 2017. Due to the Waiver Agreement, the Company recorded $0 in research and development - licenses acquired for the year ended December 31, 2018.

Fair Value Measurement, Policy [Policy Text Block]

Fair Value Measurement

The Company follows accounting guidance on fair value measurements for financial assets and liabilities measured at fair value on a recurring basis. Under the accounting guidance, fair value is defined as an exit price, representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. As such, fair value is a market-based measurement that should be determined based on assumptions that market participants would use in pricing an asset or a liability.

The accounting guidance requires fair value measurements be classified and disclosed in one of the following three categories:

Level 1:

Quoted prices in active markets for identical assets or liabilities.

Level 2

: Observable inputs other than Level 1 prices, for similar assets or liabilities that are directly or indirectly observable in the marketplace.

Level 3

: Unobservable inputs which are supported by little or no market activity and that are financial instruments whose values are determined using pricing models, discounted cash flow methodologies, or similar techniques, as well as instruments for which the determination of fair value requires significant judgment or estimation.

The fair value hierarchy also requires an entity to maximize the use of observable inputs and minimize the use of unobservable inputs when measuring fair value. Assets and liabilities measured at fair value are classified in their entirety based on the lowest level of input that is significant to the fair value measurement. The Company’s assessment of the significance of a particular input to the fair value measurement in its entirety requires management to make judgments and consider factors specific to the asset or liability.

Share-based Compensation, Option and Incentive Plans Policy [Policy Text Block]

Stock-Based Compensation

The Company expenses stock-based compensation to employees and board members over the requisite service period based on the estimated grant-date fair value of the awards. Stock-based awards with graded-vesting schedules are recognized on a straight-line basis over the requisite service period for each separately vesting portion of the award. For stock-based compensation awards to non-employees, the Company measures the fair value of the non-employee awards at each reporting period prior to vesting and finally at the vesting date of the award. Changes in the estimated fair value of these non-employee awards are recognized as compensation expense in the period of change.

The assumptions used in calculating the fair value of stock-based awards represent management’s best estimates and involve inherent uncertainties and the application of management’s judgment.

Fair Value Option [Policy Text Block]

Fair Value Option

As permitted under ASC 825,

Financial Instruments

, (“ASC 825”), the Company has elected the fair value option to account for its convertible notes that were issued during 2016. In accordance with ASC 825, the Company records these convertible notes at fair value with changes in fair value recorded in the Statement of Operations. As a result of applying the fair value option, direct costs and fees related to the convertible notes were recognized in earnings as incurred and were not deferred.

Derivatives, Reporting of Derivative Activity [Policy Text Block]

Valuation of Warrant Related to NSC Note

In accordance with ASC 815

Derivatives and Hedging

, the Company classified the fair value of the warrant (“Contingently Issuable Warrants”) that it may be obligated to issue to National Securities, Inc. (“NSC”), in connection with the transfer on October 31, 2015 of $3.0 million of indebtedness to NSC, as a derivative liability as there was a potential that the Company would not have a sufficient number of authorized common shares available to settle this instrument. The Company valued these Contingently Issuable Warrants using a Black-Scholes model and used estimates for an expected dividend yield, a risk-free interest rate, and expected volatility together with management’s estimate of the probability of issuance of the Contingently Issuable Warrants. At each reporting period, as long as the Contingently Issuable Warrants were potentially issuable and there was a potential for an insufficient number of authorized shares available to settle the Contingently Issuable Warrants, the Contingently Issuable Warrants had to be revalued and any difference from the previous valuation date would be recognized as a change in fair value in the Company’s statement of operations. On June 26, 2017, the warrants were issued (See Note 9).

Income Tax, Policy [Policy Text Block]

Income Taxes

The Company accounts for income taxes under ASC 740,

Income Taxes

(“ASC 740”). ASC 740 requires the recognition of deferred tax assets and liabilities for both the expected impact of differences between the financial statement and tax basis of assets and liabilities and for the expected future tax benefit to be derived from tax loss and tax credit carry forwards. ASC 740 additionally requires a valuation allowance to be established when it is more likely than not that all or a portion of deferred tax assets will not be realized.

ASC 740 also clarifies the accounting for uncertainty in income taxes recognized in an enterprise’s financial statements and prescribes a recognition threshold and measurement process for financial statement recognition and measurement of a tax position taken or expected to be taken in a tax return. For those benefits to be recognized, a tax position must be more-likely-than-not to be sustained upon examination by taxing authorities. ASC 740 also provides guidance on de-recognition, classification, interest and penalties, accounting in interim period, disclosure and transition. Based on the Company’s evaluation, it has been concluded that there are no significant uncertain tax positions requiring recognition in the Company’s financial statements. Since the Company was incorporated on February 9, 2015, the 2015 through 2018 tax years are the only periods subject to examination upon filing of appropriate tax returns. The Company believes that its income tax positions and deductions would be sustained on audit and does not anticipate any adjustments that would result in a material change to its financial position.

The Company’s policy for recording interest and penalties associated with audits is to record such expense as a component of income tax expense. There were no amounts accrued for penalties or interest as of or during the years ended December 31, 2018 and 2017. Management is currently unaware of any issues under review that could result in significant payments, accruals or material deviations from its position.

Earnings Per Share, Policy [Policy Text Block]

Net loss per Share

Loss per share is computed by dividing net loss by the weighted-average number of common shares outstanding, excluding unvested restricted stock and stock options, during the period. Since dividends are declared paid and set aside among the holders of shares of common stock and Class A common stock pro-rata on an as-if-converted basis, the two-class method of computing net loss per share is not required.

The following table sets forth the potential common shares that could potentially dilute basic income per share in the future that were not included in the computation of diluted income (loss) per share because to do so would have been anti-dilutive for the periods presented:

	For the Years Ended
	December 31,		December 31,
	2018		2017
Restricted stock units/awards		1,104,643		714,999
Preferred shares		250,000		250,000
Options		20,000		20,000
Total potential dilutive effect		1,374,643		984,999

Comprehensive Income, Policy [Policy Text Block]

Comprehensive Loss

The Company has no components of other comprehensive loss, and therefore, comprehensive loss equals net loss.

New Accounting Pronouncements, Policy [Policy Text Block]

Recently Adopted Accounting Standards

In January 2017, the FASB issued ASU No. 2017-01,

Business Combinations (Topic 805) Clarifying the Definition of a Business

(“ASU 2017-01”). The amendments in this ASU clarify the definition of a business with the objective of adding guidance to assist entities with evaluating whether transactions should be accounted for as acquisitions (or disposals) of assets or businesses. The definition of a business affects many areas of accounting including acquisitions, disposals, goodwill, and consolidation. The guidance is effective for annual periods beginning after December 15, 2017, including interim periods within those periods. The Company adopted ASU 2017-01 in the first quarter of 2018 and its adoption did not have a material impact on the Company’s 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. It is effective prospectively for the annual period ending December 31, 2018 and interim periods within that annual period. Early adoption is permitted. The Company early adopted ASU 2017-09 in the first quarter of 2018 and its adoption did not have a material impact on the Company’s financial statements.

In June 2018, the FASB issued ASU No. 2018-07,

Improvements to Nonemployee Share-Based Payment Accounting

, (“ASU 2018-07”) which simplifies the accounting for share-based payments granted to nonemployees for goods and services. Under the ASU, most of the guidance on such payments to nonemployees would be aligned with the requirements for share-based payments granted to employees. The changes take effect for public companies for fiscal years starting after December 15, 2018, including interim periods within that fiscal year. For all other entities, the amendments are effective for fiscal years beginning after December 15, 2019, and interim periods within fiscal years beginning after December 15, 2020. Early adoption is permitted, but no earlier than an entity’s adoption date of Topic 606. The Company adopted ASU 2018-07 in the first quarter of 2019 and its adoption did not have a material impact on the Company’s financial statements and related disclosures.

Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2018

Accounting Policies [Abstract]

Schedule of Earnings Per Share, Basic, by Common Class, Including Two Class Method [Table Text Block]

The following table sets forth the potential common shares that could potentially dilute basic income per share in the future that were not included in the computation of diluted income (loss) per share because to do so would have been anti-dilutive for the periods presented:

	For the Years Ended
	December 31,		December 31,
	2018		2017
Restricted stock units/awards		1,104,643		714,999
Preferred shares		250,000		250,000
Options		20,000		20,000
Total potential dilutive effect		1,374,643		984,999

Accounts Payable and Accrued Expenses (Tables)

12 Months Ended

Dec. 31, 2018

Payables and Accruals [Abstract]

Schedule of Accounts Payable and Accrued Liabilities [Table Text Block]

Accounts payable, accrued expenses and other liabilities consisted of the following (in thousands):

	As of December 31,
	2018		2017
Accounts payable	$	3,089	$	1,545
Accrued employee compensation		463		215
Accrued contracted services and other		1,117		977
Accounts payable and accrued expenses	$	4,669	$	2,737

Notes Payable (Tables)

12 Months Ended

Dec. 31, 2018

Debt Disclosure [Abstract]

Schedule of Long-term Debt Instruments [Table Text Block]

The following table summarizes NSC Note activities as of December 31, 2018 (in thousands):

	Note Payable			Discount			Note Payable, Net
December 31, 2016 balance	$	3,000		$	(174	)	$	2,826
Repayments		(3,000	)		-			(3,000	)
Amortization of debt discount		-			174			174
December 31, 2017 balance	$	-		$	-		$	-
December 31, 2018 balance	$	-		$	-		$	-

- Definition

Tabular disclosure of long-debt instruments or arrangements, including identification, terms, features, collateral requirements and other information necessary to a fair presentation. These are debt arrangements that originally required repayment more than twelve months after issuance or greater than the normal operating cycle of the entity, if longer.

+ References

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+ Details

Stockholders' Equity (Deficit) (Tables)

12 Months Ended

Dec. 31, 2018

Equity [Abstract]

Schedule of Unvested Restricted Stock Units Roll Forward [Table Text Block]

The following table summarizes restricted stock unit and award activity for the year ended December 31, 2018:

	Number of Units and Awards			Weighted Average Grant Date Fair Value
Unvested balance at December 31, 2017		714,999		$	5.00
Granted		467,978		$	3.48
Vested		(78,334	)	$	2.05
Unvested balance at December 31, 2018		1,104,643		$	4.45

Share-based Compensation, Stock Options, Activity [Table Text Block]

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

	Stock Options		Weighted Average Exercise Price		Weighted Average Remaining Contractual Life (in years)
Outstanding, December 31, 2017		20,000	$	6.29		4.63
Granted		-		-		-
Outstanding, December 31, 2018		20,000	$	6.29		3.63

Share-based Compensation, Activity [Table Text Block]

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

	Warrants			Weighted Average Exercise Price		Aggregate Intrinsic Value (in thousands)
Outstanding, December 31, 2017		123,413		$	0.0811	$	438
Exercised		(20,816	)	$	0.0001		-
Outstanding, December 31, 2018		102,597		$	0.0976	$	544

Fair Value Measurement (Tables)

12 Months Ended

Dec. 31, 2018

Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block]

The following table sets forth the changes in the estimated fair value for the Company’s Level 3 classified derivative warrant liability (in thousands):

	NSC Contingently Issuable Warrants			Westpark Contingently Issuable Warrants			Total
Fair value, December 31, 2016	$	302		$	12		$	314
Change in fair value		448			3			451
Conversion into common shares		(750	)		-			(750	)
Change in fair value of convertible notes warrants		-			(15	)		(15	)
Fair value, December 31, 2017		-			-			-
Change in fair value		-			-			-
Fair value, December 31, 2018	$	-		$	-		$	-

Westpark Contingently Issuable Warrants [Member]

Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block]

The following table sets forth the changes in the estimated fair value for our Level 3 classified convertible notes payable (in thousands):

	Westpark Convertible Notes
Fair value, December 31, 2016	$	200
Change in fair value		99
Conversion into common shares		(299	)
Fair value, December 31, 2017	$	-
Change in fair value		-
Fair value, December 31, 2018	$	-

Income Taxes (Tables)

12 Months Ended

Dec. 31, 2018

Income Tax Disclosure [Abstract]

Schedule of Effective Income Tax Rate Reconciliation [Table Text Block]

A reconciliation of the statutory U.S. federal rate to the Company’s effective tax rate is as follows:

	For the years ended December 31,
	2018			2017
Statutory federal income tax rate		21	%		35	%
State taxes, net of federal tax benefit		9	%		8	%
Federal tax rate change		0	%		(20	)%
State tax rate change		0	%		1	%
Non-deductible items		0	%		(3	)%
Other		0	%		(1	)%
Credits		5	%		1	%
Change in valuation allowance		(35	)%		(21	)%
Income taxes provision (benefit)		0	%		0	%

Schedule of Deferred Tax Assets and Liabilities [Table Text Block]

The components of the net deferred tax asset as of December 31, 2018 and 2017 are the following (in thousands):

	As of December 31,
	2018			2017
Deferred tax assets:
Net operating loss carryovers	$	10,160		$	4,220
Stock compensation and other		658			70
Change in warrant liabilities		-			226
Amortization of license		1,006			1,064
Accruals and reserves		221			8
Tax credits		1,294			154
Total deferred tax assets		13,339			5,742
Less valuation allowance		(13,339	)		(5,742	)
Deferred tax assets, net of valuation allowance	$	-		$	-

Organization, Plan of Business Operations (Details Textual) - USD ($) $ / shares in Units, $ in Thousands	Feb. 08, 2019	Dec. 31, 2018	Nov. 12, 2018	Dec. 31, 2017
Retained Earnings (Accumulated Deficit)		$ (42,209)		$ (20,661)
Invagen Pharmaceuticals Inc [Member]
Business Acquisition, Equity Interest Issued or Issuable, Value Assigned			$ 215,000
Invagen Pharmaceuticals Inc [Member] \| Common Stock [Member]
Stock Issued During Period, Value, Acquisitions	$ 180,000
Subsequent Event [Member] \| Line of Credit [Member]
Initial Financing Amount	3,000
Interim Financing Amount	$ 7,000
Subsequent Event [Member] \| Invagen Pharmaceuticals Inc [Member]
Business Acquisition, Equity Interest Issued or Issuable, Number of Shares	5,833,333
Business Acquisition, Equity Interest Issued or Issuable, Value Assigned	$ 31,500
Business Acquisition, Share Price	$ 6.00
Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners	33.30%

Significant Accounting Policies (Details) - shares	12 Months Ended
Significant Accounting Policies (Details) - shares	Dec. 31, 2018	Dec. 31, 2017
Total potential dilutive effect shares outstanding	1,374,643	984,999
Restricted stock units/awards
Total potential dilutive effect shares outstanding	1,104,643	714,999
Preferred shares
Total potential dilutive effect shares outstanding	250,000	250,000
Options
Total potential dilutive effect shares outstanding	20,000	20,000

Significant Accounting Policies (Details Textual) - USD ($)	1 Months Ended					12 Months Ended
	Sep. 30, 2017	Jul. 31, 2017	Jun. 26, 2017	Sep. 30, 2016	Oct. 31, 2015	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Stock Issued During Period, Shares, New Issues				250,000
Preferred Stock, Dividend Rate, Percentage				2.50%
Debt Instrument, Decrease, Forgiveness					$ 3,000,000
Payments to Acquire Investments	$ 5,000,000	$ 5,000,000				$ 0
Short-term Investments						0	$ 10,000,000
Research and Development in Process						0	1,103,000
Stockholders' Equity, Reverse Stock Split			presented to reflect the 3.0-to-1.0 reverse stock split.
Fortress Biotech, Inc [Member]
Research and Development in Process						$ 0	$ 1,100,000	$ 49,000

Allocation (Details Textual) - USD ($)	1 Months Ended		12 Months Ended
Allocation (Details Textual) - USD ($)	Jun. 30, 2017	Jun. 26, 2017	Dec. 31, 2018	Dec. 31, 2017
Allocated Compensation Expense			$ 0	$ 200,000
Compensation Allocation Percentage	100.00%
IPO [Member]
Allocated Compensation Expense		$ 600,000
Research and Development Expense [Member]
Compensation Allocation Percentage			50.00%
General and Administrative Expense [Member]
Compensation Allocation Percentage			50.00%

License Agreement (Details Textual) - USD ($) $ in Millions	1 Months Ended
License Agreement (Details Textual) - USD ($) $ in Millions	Oct. 29, 2018	Jun. 17, 2015
Revogenex License [Member]
Contractual Obligation, Maximum Future Payments		$ 4.0
IV Tramadol [Member] \| Fortress Biotech, Inc [Member]
Payments to Acquire in Process Research and Development		3.0
IV Tramadol [Member] \| Fortress Biotech, Inc [Member] \| Upfront Payment [Member]
Payments to Acquire in Process Research and Development		2.0
IV Tramadol [Member] \| Fortress Biotech, Inc [Member] \| Additional Payment [Member]
Payments to Acquire in Process Research and Development		$ 1.0
Polharma [Member]
Payments to Acquire in Process Research and Development	$ 2.0

Related Party Agreements (Details Textual) - USD ($)				1 Months Ended				12 Months Ended
Related Party Agreements (Details Textual) - USD ($)	Jul. 05, 2017	May 15, 2017	Sep. 13, 2016	Jun. 26, 2017	Jun. 25, 2017	Sep. 30, 2016	Feb. 17, 2015	Dec. 31, 2018	Dec. 31, 2017	May 17, 2017	Dec. 31, 2016	Mar. 15, 2015
Agreement Description Terms								(i) issue annually to Fortress, on the anniversary date of the Founders Agreement, shares of common stock equal to two and one half percent (2.5%) of the fully-diluted outstanding equity of Avenue at the time of issuance; (ii) pay an equity fee in shares of Avenue common stock, payable within five (5) business days of the closing of any equity or debt financing for Avenue or any of its respective subsidiaries that occurs after the effective date of the Founders Agreement and ending on the date when Fortress no longer has majority voting control in Avenue’s voting equity, equal to two and one half percent (2.5%) of the gross amount of any such equity or debt financing; and (iii) pay a cash fee equal to four and one half percent (4.5%) of Avenue’s annual net sales, payable on an annual basis, within ninety (90) days of the end of each calendar year. In the event of a change in control (as it is defined in the Founders Agreement), Fortress will be paid a one-time change in control fee equal to five (5x) times the product of (i) net sales for the twelve (12) months immediately preceding the change in control and (ii) four and one-half percent (4.5%).
Stock Issued During Period, Value, New Issues								$ 0	$ 948,000
Stockholders' Equity, Period Increase (Decrease)									632,000
Deferred Offering Costs								1,702,000	0
Debt Instrument, Periodic Payment, Principal					$ 3,500,000
Debt Instrument, Periodic Payment, Interest					$ 100,000
Service Agreement Expenses								400,000	500,000
Extend Loan Modification, Reduction to interest Expense								300,000
IPO [Member]
Number of shares Exchanged				158,125
Financing Fee				$ 0.9
Common Stock [Member]
Stock Issued During Period, Value, New Issues								0	0
Stockholders' Equity, Period Increase (Decrease)									0
Fortress Note [Member]
Debt Instrument, Interest Rate, Stated Percentage												8.00%
Interest Expense, Debt				$ 300,000				0	74,000
Fortress Note [Member] \| Maximum [Member]
Annual Consulting Fee								$ 400,000
Debt Instrument, Interest Rate, Stated Percentage								8.00%		8.00%
Fortress Note [Member] \| Minimum [Member]
Annual Consulting Fee								$ 100,000
Debt Instrument, Interest Rate, Stated Percentage								2.00%		2.00%
Fortress Note [Member] \| IPO [Member]
Stockholders' Equity, Period Increase (Decrease)		$ 500,000
Percentage Of Conversion Shares				2.50%
NSC Notes Memebers [Member]
Long-term Debt, Gross							$ 3,000,000	$ 0	$ 0		$ 3,000,000
Debt Instrument, Periodic Payment, Interest	$ 2,000
NSC Notes Memebers [Member] \| IPO [Member]
Stock Issued During Period, Value, New Issues				$ 125,000
Deferred Offering Costs				3,000,000
National Holdings, Inc. [Member]
Long-term Debt						$ 3,000,000
Business Acquisition, Percentage of Voting Interests Acquired						56.60%
Placement Fee, Percentage						10.00%
Debt Instrument, Periodic Payment, Principal						$ 3,000,000
Debt Instrument, Periodic Payment, Interest						$ 2,000
National Holdings, Inc. [Member] \| IPO [Member]
Earnings of commission and fees				2,300,000
Asset Management Income [Member]
Annual Consulting Fee				500,000
Increase In Annual Consulting Fee							1,000,000
Excess In Net Assets Value							100,000,000
Asset Management Income [Member] \| IPO [Member]
Stock Issued During Period, Value, New Issues				166,666
Due to Related Parties, Current				$ 1,000,000
Shares Issued, Price Per Share				$ 6.00
AR Founders Agreement [Member]
Amended Founders Agreements Terms			15 years
AR Founders Agreement [Member] \| Common Stock [Member]
Number of shares Exchanged			2,500,000
Fortress Biotech, Inc [Member]
Long-term Debt, Gross							$ 3,000,000
Preferred Class A [Member] \| AR Founders Agreement [Member]
Number of shares Exchanged			250,000
Common Class A [Member] \| AR Founders Agreement [Member]
Number of shares Exchanged			2,300,000

Accounts Payable and Accrued Expenses (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Accounts payable	$ 3,089	$ 1,545
Accrued employee compensation	463	215
Accrued contracted services and other	1,117	977
Accounts payable and accrued expenses	$ 4,669	$ 2,737

Notes Payable (Details) - USD ($)		12 Months Ended
Notes Payable (Details) - USD ($)	Jul. 05, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Note Payable Repayments		$ 0	$ (3,000,000)
Note Payable Amortization of debt discount		0	174,000
Discount Amortization Of debt discount			174,000
Notes Payable, Net Beginning		0	2,826,000
Notes Payable, Net Ending		0	0	$ 2,826,000
NSC Notes Memebers [Member]
Note Payable balance Beginning		0	3,000,000
Note Payable Repayments	$ (3,000,000)		(3,000,000)	(3,000,000)
Note Payable Amortization of debt discount			0
Note Payable balance Ending		0	0	3,000,000
Discount Beginning		0	(174,000)
Discount Amortization Of debt discount			174,000
Discount Ending		0	0	$ (174,000)
Notes Payable, Net Beginning		$ 0
Notes Payable, Net Ending			$ 0

Notes Payable (Details Textual) - USD ($)		1 Months Ended				12 Months Ended
Notes Payable (Details Textual) - USD ($)	Jul. 05, 2017	Jun. 26, 2017	Jun. 25, 2017	Dec. 30, 2016	Sep. 30, 2016	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Feb. 28, 2015
Repayments of Notes Payable						$ 0	$ 3,000,000
Debt Instrument, Periodic Payment, Interest			$ 100,000
Stock Issued During Period, Shares, New Issues					250,000
Stock Issued During Period, Value, New Issues						0	948,000
Notes Payable						0	0	$ 2,826,000
Convertible Debt, Fair Value Disclosures				$ 200,000
Debt Conversion, Converted Instrument, Shares Issued		49,748
IPO [Member]
Stock Issued During Period, Shares, New Issues		6,325,000
Fortress Biotech, Inc [Member] \| IPO [Member]
Stock Issued During Period, Shares, New Issues		125,000
Stock Issued During Period, Value, New Issues		$ 800,000
NSC Notes Memebers [Member]
Repayments of Notes Payable	$ 3,000,000						3,000,000	3,000,000
Debt Instrument, Periodic Payment, Interest	$ 2,000
Notes Payable							0
Debt Instrument, Unamortized Discount						$ 0	$ 0	174,000
NSC Notes Memebers [Member] \| IPO [Member]
Stock Issued During Period, Value, New Issues		125,000
NSC Notes Memebers [Member] \| Fortress Biotech, Inc [Member]
Debt Instrument, Term						10 years
Debt Instrument, Interest Rate, Stated Percentage						8.00%
Debt Instrument, Maturity Date, Description						The note matures in 36 months, provided that during the first 24 months Fortress can extend the maturity date by six months. No principal amount will be due for the first 24 months (or the first 30 months if the maturity date is extended). Thereafter
Contingently Issuable Warrants Percentage						25.00%
Debt Issuance Costs, Net								$ 200,000
Debt Instrument, Interest Rate, Effective Percentage								13.10%
Debt Instrument, Unamortized Discount								$ 100,000
NSC Notes Memebers [Member] \| Avenue Therepeutics parent co [Member]
Debt Instrument, Face Amount		$ 3,000,000							$ 10,000,000
Convertible Note Payable [Member] \| Fortress Biotech, Inc [Member]
Debt Instrument, Term				18 months
Convertible Notes Payable, Current				$ 200,000
Debt Instrument Interest Rate Stated Percentage current Year				5.00%
Debt Instrument Interest Rate Stated Percentage after Twelve Month				8.00%
Proceeds from Issuance or Sale of Equity				$ 10,000,000
Net Proceeds From Issuance Of Private Placement After Paying Fees				100,000
Payments For Placement Fee				30,000
Payments for Other Fees				4,000
Professional Fees				14,000
Class Of Warrant Or Right Value Of Securities Called By Warrants Or Rights				10,000
Maximum Threshold Limit for Conversion into Equity				$ 10,000,000
Convertible Note Payable [Member] \| Fortress Biotech, Inc [Member] \| Conversion One [Member]
Debt Instrument, Convertible, Terms of Conversion Feature				(a) the lowest price per share at which equity securities of Avenue are sold in such sale less a 33% discount and (b) a per share price based on a pre-offering valuation of $30.0 million divided by the number of common shares outstanding on a fully-diluted basis.
Convertible Note Payable [Member] \| Fortress Biotech, Inc [Member] \| Conversion Two [Member]
Debt Instrument, Convertible, Terms of Conversion Feature				(a) a discount to the price per share being paid in the Sale of Avenue equal to 33% or (b) the quotient resulting from dividing (x) $30.0 million by (y) the fully-diluted common stock of Avenue outstanding immediately prior to the Sale of Avenue (excluding the notes)

Stockholders' Equity (Deficit) (Details) - Restricted Stock [Member]	12 Months Ended
	Dec. 31, 2018 $ / shares shares
Number of Units, Unvested Beginning Balance \| shares	714,999
Number of Units, Granted \| shares	467,978
Number of Units, Vested \| shares	(78,334)
Number of Units, Unvested Ending Balance \| shares	1,104,643
Weighted Average Grant Date Fair Value, Unvested Beginning Balance \| $ / shares	$ 5.00
Weighted Average Grant Date Fair Value, Granted \| $ / shares	3.48
Weighted Average Grant Date Fair Value, Vested \| $ / shares	2.05
Weighted Average Grant Date Fair Value, Unvested Ending Balance \| $ / shares	$ 4.45

Stockholders' Equity (Deficit) (Details1) - $ / shares		12 Months Ended
Stockholders' Equity (Deficit) (Details1) - $ / shares	Aug. 15, 2017	Dec. 31, 2018	Dec. 31, 2017
Stock Options, Outstanding, Begining		20,000
Stock Options, Granted	20,000	0
Stock Options, Outstanding, Ending		20,000	20,000
Weighted Average Exercise Price, Outstanding, Begining		$ 6.29
Weighted Average Exercise Price, Granted	$ 6.29	0
Weighted Average Exercise Price, Outstanding, Ending		$ 6.29	$ 6.29
Weighted Average Remaining Contractual Life		3 years 7 months 17 days	4 years 7 months 17 days

Stockholders' Equity (Deficit) (Details2) - Warrant [Member] - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Number of Units, Unvested Beginning Balance	123,413
Warrants, Exercise	(20,816)
Number of Units, Unvested Ending Balance	102,597
Weighted Average Exercise Price, Outstanding	$ 0.0811
Weighted Average Exercise Price, Exercised	0.0001
Weighted Average Exercise Price, Outstanding	$ 0.0976
Aggregate Intrinsic Value	$ 544	$ 438

Stockholders' Equity (Deficit) (Details Textual) - USD ($)				1 Months Ended				12 Months Ended
	Nov. 12, 2018	Aug. 15, 2017	Sep. 13, 2016	Feb. 17, 2018	Jun. 26, 2017	Feb. 17, 2017	Sep. 30, 2016	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Preferred Stock, Shares Authorized								2,000,000	2,000,000
Common Stock, Shares Authorized								50,000,000	50,000,000
Common Stock, Par or Stated Value Per Share								$ 0.0001	$ 0.0001
Share-based Compensation								$ 1,537,000	$ 604,000
Share Price		$ 1.85			$ 6.00
Stock Issued During Period, Value, New Issues								$ 0	948,000
Stock Issued During Period, Shares, New Issues							250,000
Stock Issued During Period, Shares, Issued for Services					166,666			250,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross		20,000						0
Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price		$ 6.29						$ 0
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate		80.00%
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate		1.83%
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Term		5 years
Research and Development in Process								$ 0	$ 1,103,000
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Exercise Price		$ 6.29
Stock or Unit Option Plan Expense		$ 37,000
Preferred Stock, Par or Stated Value Per Share								$ 0.0001	$ 0.0001
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage	(100.00%)
2015 Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized								2,000,000
Share-based Compensation Arrangement by Share-based Payment Award, Plan Modification, Description and Terms								10 years
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant								647,022
Fortress Biotech, Inc [Member]
Stock Issued During Period, Value, Issued for Services					$ 1,000,000
Stock Issuance Common Stock Issuable During Period, Shares				273,837		83,532
Percentage of Diluted outstanding Equity				2.50%		2.50%
Research and Development in Process								$ 0	$ 1,100,000	$ 49,000
Common Stock [Member]
Stock Issued During Period, Value, New Issues								$ 0	$ 0
Stock Issued During Period, Shares, New Issues								273,837	241,657
Stock Issued During Period, Shares, Issued for Services									500,000
Stock Issuance Common Stock Issuable During Period, Shares									0
AR Founders Agreement [Member]
Amended Founders Agreements Terms			15 years
AR Founders Agreement [Member] \| Common Stock [Member]
Number of shares Exchanged			2,500,000
Fortress Notes [Member]
Share Price					$ 6.00
Stock Issued During Period, Shares, New Issues					158,125
Other Fees and Commissions, Percentage					2.50%
IPO [Member]
Share Price					$ 6.00
Stock Issued During Period, Shares, New Issues					6,325,000
Proceeds from Issuance Initial Public Offering					$ 34,200,000
Number of shares Exchanged					158,125
IPO [Member] \| Fortress Biotech, Inc [Member]
Stock Issued During Period, Value, New Issues					$ 800,000
Stock Issued During Period, Shares, New Issues					125,000
Over-Allotment Option [Member]
Stock Issued During Period, Shares, New Issues					825,000
NSC Note [Member]
Conversion of Stock, Description					As a result, the Company issued warrants for 125,000 common shares with an exercise price of par value and a ten-year term. As a result of this transaction, the Company recorded the fair value of the Contingently Issuable Warrants of approximately $0.8 million as an increase to additional paid in capital on the Statement of Stockholders’ Equity (Deficit).
West Park [Member]
Common Stock, Par or Stated Value Per Share					$ 4.02
Incremental Common Shares Attributable to Dilutive Effect of Call Options and Warrants					2,488
West Park [Member] \| IPO [Member]
Common Stock, Par or Stated Value Per Share					$ 4.02
Incremental Common Shares Attributable to Dilutive Effect of Call Options and Warrants					2,488
Share Price					$ 6.00
Restricted Stock [Member]
Share-based Compensation								$ 1,500,000	$ 600,000
Employee Service Share-based Compensation, Nonvested Awards, Compensation Not yet Recognized, Share-based Awards Other than Options								$ 3,300,000
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition								2 years
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value								$ 3.48
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value								$ 3.48	$ 6.77
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Fair Value								$ 100,000	$ 33,000
Preferred Class A [Member]
Preferred Stock, Shares Outstanding								250,000
Common Stock, Par or Stated Value Per Share								$ 0.0001
Preferred Class A [Member] \| AR Founders Agreement [Member]
Number of shares Exchanged			250,000
Common Class A [Member] \| AR Founders Agreement [Member]
Number of shares Exchanged			2,300,000

Fair Value Measurement (Details) - USD ($) $ in Thousands	12 Months Ended
Fair Value Measurement (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Conversion into common shares	$ 0	$ (1,000)
Change in fair value of convertible notes warrants	0	(15)
Warrant [Member]
Fair value, Beginning Balance	0	314
Change in fair value	0	451
Conversion into common shares		(750)
Change in fair value of convertible notes warrants		(15)
Fair value, Ending Balance	0	0
Warrant [Member] \| NSC Contingently Issuable Warrants [Member]
Fair value, Beginning Balance	0	302
Change in fair value	0	448
Conversion into common shares		(750)
Change in fair value of convertible notes warrants		0
Fair value, Ending Balance	0	0
Warrant [Member] \| Westpark Contingently Issuable Warrants [Member]
Fair value, Beginning Balance	0	12
Change in fair value	0	3
Conversion into common shares		0
Change in fair value of convertible notes warrants		(15)
Fair value, Ending Balance	$ 0	$ 0

Fair Value Measurement (Details 1) - USD ($) $ in Thousands	12 Months Ended
Fair Value Measurement (Details 1) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Conversion into common shares	$ 0	$ (1,000)
Debt [Member]
Fair value, Beginning Balance	0	200
Change in fair value	0	99
Conversion into common shares		(299)
Fair value, Ending Balance	$ 0	$ 0

Fair Value Measurement (Details Textual) - USD ($)	1 Months Ended
Fair Value Measurement (Details Textual) - USD ($)	Jun. 26, 2017	Dec. 31, 2018	Dec. 31, 2017
Warrants Not Settleable in Cash, Fair Value Disclosure		$ 0	$ 0
Common Stock, Par or Stated Value Per Share		$ 0.0001	$ 0.0001
NSC Notes [Member]
Debt Instrument, Face Amount	$ 3,000,000
Debt Conversion, Converted Instrument, Warrants or Options Issued	125,000
West Park [Member]
Incremental Common Shares Attributable to Dilutive Effect of Call Options and Warrants	2,488
Common Stock, Par or Stated Value Per Share	$ 4.02
NSC Contingently Issuable Warrants [Member] \| NSC Notes [Member]
Warrants Not Settleable in Cash, Fair Value Disclosure	$ 800,000

Income Taxes (Details)	12 Months Ended
Income Taxes (Details)	Dec. 31, 2018	Dec. 31, 2017
Statutory federal income tax rate	21.00%	35.00%
State taxes, net of federal tax benefit	9.00%	8.00%
Federal tax rate change	0.00%	(20.00%)
State tax rate change	0.00%	1.00%
Non-deductible items	0.00%	(3.00%)
Other	0.00%	(1.00%)
Credits	5.00%	1.00%
Change in valuation allowance	(35.00%)	(21.00%)
Income taxes provision (benefit)	0.00%	0.00%

Income Taxes (Details 1) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Deferred tax assets:
Net operating loss carryovers	$ 10,160	$ 4,220
Stock compensation and other	658	70
Change in warrant liabilities	0	226
Amortization of license	1,006	1,064
Accruals and reserves	221	8
Tax credits	1,294	154
Total deferred tax assets	13,339	5,742
Less valuation allowance	(13,339)	(5,742)
Deferred tax assets, net of valuation allowance	$ 0	$ 0

Income Taxes (Details Textual) - USD ($) $ in Thousands	12 Months Ended
Income Taxes (Details Textual) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Deferred Tax Assets, Valuation Allowance	$ 13,339	$ 5,742
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent	21.00%	35.00%
Research and Development Expense	$ 17,696	$ 6,698
Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount		$ 2,500
Domestic Tax Authority [Member]
Operating Loss Carryforwards	$ 34,500
Operating Loss Carry forward, Expire Period	2035 years
State and Local Jurisdiction [Member]
Operating Loss Carryforwards	$ 43,100
Operating Loss Carry forward, Expire Period	2035 years

Subsequent Events (Details Textual) - Invagen Pharmaceuticals Inc [Member] - USD ($) $ / shares in Units, $ in Millions	Feb. 08, 2019	Nov. 12, 2018
Business Acquisition, Equity Interest Issued or Issuable, Value Assigned		$ 215.0
Subsequent Event [Member]
Business Acquisition, Equity Interest Issued or Issuable, Value Assigned	$ 31.5
Business Acquisition, Equity Interest Issued or Issuable, Number of Shares	5,833,333
Business Acquisition, Share Price	$ 6.00
Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners	33.30%