0001437749-24-007853 | 10-K | XBRL Viewer

Share-Based Payment Arrangement [Text Block]

Note 8 — Share-Based Payment Awards

The Company’s board of directors and stockholders approved the Eton Pharmaceuticals, Inc. 2017 Equity Incentive Plan in May 2017 (the “2017 Plan”), which authorized the issuance of up to 5,000,000 shares of the Company’s common stock. In conjunction with the Company’s IPO in November 2018, the Company’s stockholders and board of directors approved the 2018 Equity Incentive Plan, as amended (the “2018 Plan”) which succeeded the 2017 Plan. The Company has granted RSAs, stock options and RSUs for its common stock under the 2017 Plan and 2018 Plan as detailed in the tables below. There were 663,598 shares available for future issuance under the 2018 Plan as of December 31, 2023.

Note 8 — Share-Based Payment Awards (continued)

Shares that are expired, terminated, surrendered or canceled without having been fully exercised will be available for future awards under the 2018 Plan. In addition, the 2018 Plan provides that commencing January 1, 2019 and through January 1, 2028, the share reserve will be increased by 4% of the total number of shares outstanding as of the preceding December 31, subject to a reduction at the discretion of the Company’s board of directors. On January 1, 2021, the share reserve was increased by 972,512 shares based on the 24,312,808 shares of common stock outstanding at December 31, 2020. On January 1, 2022, the share reserve was increased by 985,040 shares based on the 24,626,004 shares of common stock outstanding at December 31, 2021. On January 1, 2023, the share reserve was increased by 1,014,124 shares based on the 25,353,119 shares of common stock outstanding at December 31, 2022. The exercise price for stock options granted is not less than the fair value of common stock as determined by the board of directors as of the date of grant. The Company uses the closing stock price on the date of grant as the exercise price.

To date, all stock options issued have been non-qualified stock options, and the exercise prices were set at the fair value for the shares at the dates of grant. Options typically have a ten-year life, except for options to purchase 50,000 shares of the Company’s common stock granted to product consultants in July 2017 that expired, unexercised, in July 2022 as the Company was not able to file certain product submissions to the FDA prior to the five-year expiration date. Furthermore, these option awards to the Company’s product consultants would not vest unless certain product submissions are made to the FDA, and accordingly, the Company has not recorded any expense for these contingently vesting option awards to its product consultants.

In July 2022 and September 2022, the Company’s board of directors approved modifications of certain outstanding awards of two senior executives, one of whom retired in May 2022 and the other whose employment was terminated in July 2022. The combined awards had an exercise price range of $1.37 to $8.61 which were set to expire 90 days after retirement or termination as the case may be, and the Company extended the expiration dates to April 2023. No other terms were modified. Due to these modifications, the Company incurred a modification expense of approximately $104 that is included in general and administration expense on the Statement of Operations for the year ended December 31, 2022.

For the years ended December 31, 2023, 2022 and 2021, the Company’s total stock-based compensation expense was $3,137, $4,218 and $3,381, respectively. Of these amounts, $2,864, $3,954, and $2,838 was recorded in general and administrative expenses, respectively, and $273, $264, and $543 was recorded in R&D expenses, respectively.

Stock Options

The following table summarizes stock option activity during the year ended December 31, 2023:

						*Weighted Average*
				*Weighted Average*		*Remaining*
				*Exercise*		*Contractual*		*Aggregate Intrinsic*
	*Shares*			*Price*		*Term*		*Value*
Options outstanding as of January 1, 2023		4,402,292		$	4.71
Issued		1,108,291			3.51
Exercised		(407,808	)		2.23
Forfeited/Cancelled		(263,549	)		5.94
Options outstanding as of December 31, 2023		4,839,226		$	4.57		7.3	$	3,467
Options exercisable at December 31, 2023		3,399,896		$	4.78		6.7	$	2,432
Options vested and expected to vest at December 31, 2023		4,839,226		$	4.57		7.3	$	3,467

The aggregate intrinsic value of stock options is calculated as the difference between the exercise price of the stock options and the fair value of the Company’s common stock for those stock options that had strike prices lower than the fair value of the Company’s common stock at December 31. The intrinsic value of the options exercised during 2023 was $612.

Note 8 — Share-Based Payment Awards (continued)

There were 207,626 and 25,000 shares issued for exercise of stock options during the years ended December 31, 2023 and 2022, respectively, for proceeds of $149 and $35.

The assumptions used to calculate the estimated fair value of options granted during the years ended December 31, 2023, 2022 and 2021 under the BSM were as follows:

	*December 31, 2023*			*December 31, 2022*			*December 31, 2021*
Expected dividends		—	%		—	%		—	%
Expected volatility		70	%		70	%		70 - 80	%
Risk-free interest rate		3.5 - 4.7	%		1.5 - 3.9	%		0.9 - 1.4	%
Expected term (in years)		6.3			5.9			6.0
Weighted average grant date fair value	$	2.32		$	2.32		$	5.64

Expected Term — The Company has opted to use the “simplified method” for estimating the expected term of options granted to employees and directors, whereby the expected term equals the arithmetic average of the vesting term and the original contractual term of the option (generally 10 years). The expected term of options granted to non-employees equals the contractual life of the options.

Expected Volatility — Expected volatilities are based on the Company's historical volatility subsequent to our IPO, which we believe represents the most accurate basis for estimating expected future volatility under the current conditions.

Risk-Free Interest Rate — The risk-free rate assumption is based on the U.S. Treasury instruments with maturities similar to the expected term of the Company’s stock options.

Expected Dividend — The Company has not issued any dividends in its history and does not expect to issue dividends over the life of the options and therefore has estimated the dividend yield to be zero.

Fair value of Common Stock —The Company uses the closing stock price on the date of grant for the fair value of the common stock.

As of December 31, 2023, there was a total of $3,601 of unrecognized compensation costs related to non-vested stock option awards which will be recognized over a weighted average period of 2 years.

Restricted Stock Units (RSUs)

The following table summarizes restricted stock unit activity during the year ended December 31, 2023:

				*Weighted Average Grant-Date*
	*Number of Units*			*Fair Value Per Unit*
Outstanding and unvested as of January 1, 2023		369,606		$	2.63
Granted		—			—
Vested		(91,402	)	$	2.63
Forfeited		(4,000	)	$	2.63
Outstanding and unvested as of December 31, 2023		274,204		$	2.63

Stock-based compensation related to RSUs was $239 and $114 for the years ended December 31, 2023 and 2022, respectively. As of December 31, 2023, there was $608 of unrecognized stock-based compensation expense related to unvested RSUs which will be recognized over a weighted average period of 2.5 years.

Note 8 — Share-Based Payment Awards (continued)

Employee Stock Purchase Plan

In December 2018, the Company’s board of directors adopted an initial offering of the Company’s common stock under the Company’s ESPP. The Company’s ESPP provides for an initial reserve of 150,000 shares and this reserve is automatically increased on January 1 of each year by the lesser of 1% of the outstanding common shares at December 31 of the preceding year or 150,000 shares, subject to reduction at the discretion of the Company’s board of directors.

The terms of the ESPP permit employees of the Company to use payroll deductions to purchase stock at a price per share that is at least the lesser of (1) 85% of the fair market value of a share of common stock on the first date of an offering or (2) 85% of the fair market value of a share of common stock on the date of purchase. After the initial offering period, subsequent twelve-month offering periods automatically commence over the term of the ESPP on the day that immediately follows the conclusion of the preceding offering, each consisting of two purchase periods approximately six months in duration ending on or around June 10 and December 10 each year, subject to a restart feature if the Company’s stock price drops at the end of a six-month period within the twelve-month offering period.

The Company recorded an expense of $135, $128, and $73 in 2023, 2022 and 2021, respectively, related to the ESPP. For the years ended December 31, 2023 and 2022, there were 86,782 and 69,884 share issuances, respectively, under the ESPP. The weighted average grant date fair value of share awards in 2023, 2022 and 2021 was $1.27, $1.17, and $2.50 per share, respectively. Employees contributed $230 and $174 to the ESPP during 2023 and 2022, respectively. Of these amounts, $24 and $23 at December 31, 2023 and 2022, respectively, are included in accrued liabilities in the accompanying balance sheets. As of December 31, 2023, there were 623,514 shares available for issuance under the ESPP.

Note 3 - Summary of Significant Accounting Policies (Details Textual) - USD ($) $ in Thousands	1 Months Ended			3 Months Ended	12 Months Ended
	Oct. 31, 2023	Sep. 30, 2022	Nov. 30, 2021	Mar. 31, 2022	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2019	Jun. 30, 2022
Accounts Receivable, Allowance for Credit Loss					$ 129	$ 262
Inventory Valuation Reserves					76	62
Payments to Acquire Intangible Assets					775	2,750	$ 3,250
Finite-Lived Intangible Assets, Accumulated Amortization					1,286
Amortization of Intangible Assets					790	1,617	204
Impairment, Long-Lived Asset, Held-for-Use					0	0	$ 0
Finance Lease, Liability					$ 0	$ 0
Percentage for Valuation Reserve Against Deferred Tax Assets					100.00%	100.00%
Unrecognized Tax Benefits					$ 0	$ 0
Revenue Benchmark [Member] \| Customer Concentration Risk [Member] \| AnovoRx [Member]
Concentration Risk, Percentage					78.20%	45.50%
Accounts Receivable [Member] \| Customer Concentration Risk [Member] \| AnovoRx [Member]
Concentration Risk, Percentage					97.40%	79.80%
Carglumic Acid Product Rights [Member]
Payments to Acquire Intangible Assets			$ 3,250
Finite-Lived Intangible Asset, Useful Life (Year)			10 years
Biorphen [Member]
Payments to Acquire Intangible Assets								$ 750
Finite-Lived Intangible Asset, Useful Life (Year)								5 years
Finite-Lived Intangible Assets, Accumulated Amortization									$ 275
Finite-Lived Intangible Asset, Expected Amortization, Remainder of Fiscal Year						$ 75
Rezipres Product [Member]
Payments to Acquire Intangible Assets				$ 750
Finite-Lived Intangible Asset, Useful Life (Year)				5 years
Finite-Lived Intangible Assets, Accumulated Amortization									$ 738
Betaine Anhydrous Product Rights [Member]
Payments to Acquire Intangible Assets		$ 2,125
Finite-Lived Intangible Asset, Useful Life (Year)		5 years
Nitisinone Product Rights [Member]
Payments to Acquire Intangible Assets	$ 650
Finite-Lived Intangible Asset, Useful Life (Year)	5 years
Furniture and Fixtures [Member]
Property, Plant and Equipment, Useful Life (Year)					5 years

Note 8 - Share-based Payment Awards -Schedule of Restricted Stock Unit Activity (Details) - Restricted Stock Units (RSUs) [Member]	12 Months Ended
	Dec. 31, 2023 $ / shares shares
Outstanding and unvested, balance (in shares) \| shares	369,606
Outstanding and unvested, Weighted Average Grant-Date Fair Value Per Unit (in dollars per share) \| $ / shares	$ 2.63
Granted (in shares) \| shares	0
Granted, Weighted Average Grant-Date Fair Value Per Unit (in dollars per share) \| $ / shares	$ 0
Vested (in shares) \| shares	(91,402)
Vested, Weighted Average Grant-Date Fair Value Per Unit (in dollars per share) \| $ / shares	$ 2.63
Forfeited (in shares) \| shares	(4,000)
Forfeited, Weighted Average Grant-Date Fair Value Per Unit (in dollars per share) \| $ / shares	$ 2.63
Outstanding and unvested, balance (in shares) \| shares	274,204
Outstanding and unvested, Weighted Average Grant-Date Fair Value Per Unit (in dollars per share) \| $ / shares	$ 2.63

Note 11 - Leases - Schedule of Future Lease Payments (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Nov. 30, 2022	Oct. 31, 2020
Total	$ 81
2023	58
2024	23
2025	0
Less: Imputed interest	(6)
Total lease liabilities	$ 75	$ 188	$ 195

Note 13 - Employee Savings Plan (Details Textual) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Defined Contribution Plan, Maximum Annual Contributions Per Employee, Percent	100.00%
Defined Contribution Plan, Employer Matching Contribution, Percent of Employees' Gross Pay	4.00%
Defined Contribution Plan, Employer Discretionary Contribution Amount	$ 242	$ 172	$ 154

Note 5 - Debt - Schedule of Future Payments (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
2024	$ 6,483
Total payments	6,483
Less: amount representing interest	(1,023)
Long-Term Debt, Gross	5,460
Less: unamortized discount	(80)
Current portion of long-term debt, net of discount	$ 5,380	$ 1,033

Note 12 - Income Taxes - Components of Deferred Tax Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Net operating losses	$ 15,447	$ 17,183
Stock-based expenses	3,372	3,090
Accruals and other	2,697	1,359
Total deferred tax assets	21,516	21,632
Valuation allowance	(21,516)	(21,632)
Net deferred tax assets	$ 0	$ 0

Note 9 - Basic and Diluted Net Loss per Common Share

12 Months Ended

Dec. 31, 2023

Earnings Per Share [Text Block]

Note 9 — Basic and Diluted Net Loss per Common Share

Basic and diluted net loss per share is computed using the weighted average number of shares of common stock outstanding during the period. Common stock equivalents (using the treasury stock and “if converted” method) from stock options, unvested RSAs and RSUs, and warrants at December 31, 2023, 2022 and 2021 were 5,418,251, 5,494,153, and 4,286,687, respectively, and are excluded from the calculation of diluted net loss per share because the effect is anti-dilutive. Included in the basic and diluted net loss per share calculation were RSUs awarded to directors that had vested, but the issuance and delivery of the shares are deferred until the director retires from service as a director.

The following table shows the computation of basic and diluted net loss per common share:

	*Year ended*			*Year ended*			*Year ended*
	*December 31,*			*December 31,*			*December 31,*
	*2023*			*2022*			*2021*

Net loss	$	(936	)	$	(9,021	)	$	(1,955	)
Weighted average common shares outstanding (basic and diluted)		25,645,366			25,145,657			25,207,299
Net loss per common share (basic and diluted)	$	(0.04	)	$	(0.36	)	$	(0.08	)

Note 8 - Share-Based Payment Awards - Schedule of Assumptions Used to Calculate Fair Value of Options Granted (Details) - $ / shares	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Expected volatility	70.00%	70.00%
Expected volatility			70.00%
Expected volatility			80.00%
Risk-free interest rate	3.50%	1.50%	0.90%
Risk-free interest rate	4.70%	3.90%	1.40%
Expected term (in years) (Year)	6 years 3 months 18 days	5 years 10 months 24 days	6 years
Weighted average fair value (in dollars per share)	$ 2.32	$ 2.32	$ 5.64

Significant Accounting Policies (Policies)

12 Months Ended

Dec. 31, 2023

Accounting Policies [Abstract]

Basis of Accounting, Policy [Policy Text Block]

Basis of Presentation

The Company has prepared the accompanying financial statements in accordance with GAAP.

Use of Estimates, Policy [Policy Text Block]

Use of Estimates

The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenue and expenses during the reporting periods. Significant estimates and assumptions reflected in these financial statements include, but are not limited to, provisions for uncollectible receivables, chargebacks and sales returns, Medicaid program rebates, valuation of inventories, useful lives of assets and the recoverability of long-lived assets, valuation of deferred tax assets, the accrual of research and development expenses, and the valuation of common stock, stock options, warrants, and restricted stock units (“RSUs”). Estimates are periodically reviewed in light of changes in circumstances, facts and experience. Changes in estimates are recorded in the period in which they become known. Actual results could differ from those estimates or assumptions.

Segment Reporting, Policy [Policy Text Block]

Segment Information

The Company operates the business on the basis of a single reportable segment, which is the business of developing and commercializing prescription drug products. The Company’s chief operating decision-maker is the CEO, who evaluates the Company as a single operating segment.

Cash and Cash Equivalents, Policy [Policy Text Block]

Cash and Cash Equivalents

The Company considers all highly liquid investments with an original maturity of three months or less to be cash equivalents. All cash and cash equivalents are held in U.S. financial institutions or invested in short-term U.S. treasury bills or high-grade money market funds. From time to time, amounts deposited with its bank exceed federally insured limits. The Company believes the associated credit risk to be minimal.

Accounts Receivable [Policy Text Block]

Accounts Receivable

Accounts receivable are recorded at the invoiced amount and are non-interest bearing. Accounts receivable are recorded net of allowances for doubtful accounts, cash discounts for prompt payment, distribution fees, chargebacks and returns and allowances. The Company considers historical collection rates and the current financial status of its customers, as well as macroeconomic and industry-specific factors when evaluating potential credit losses. Historically, the Company's accounts receivable balances have been highly concentrated with a select number of customers, consisting primarily of specialty pharmacies and large wholesale pharmaceutical distributors. Given the size and creditworthiness of these customers, we have not experienced and do not expect to experience material credit losses. The total for these reserves amounted to $129 and $262 as of December 31, 2023 and 2022, respectively.

Inventory, Policy [Policy Text Block]

Inventories

The Company values its inventories at the lower of cost or net realizable value using the first-in, first-out method of valuation. The Company reviews its inventories for potential excess or obsolete issues on an ongoing basis and records a write-down if an impairment is identified. Inventories at December 31, 2023 and 2022 consist primarily of purchased finished goods. At December 31, 2023 and 2022, inventories are shown net of a reserve for ALKINDI SPRINKLE® inventory due to the risk of expiry prior to being sold. There was an inventory reserve of $76 and $62 at December 31, 2023 and 2022, respectively.

Property, Plant and Equipment, Policy [Policy Text Block]

Property and Equipment

Property and equipment are stated at cost. Depreciation of property and equipment is computed utilizing the straight-line method based on the following estimated useful lives. Computer hardware and software is depreciated over three years. Equipment, furniture and fixtures is depreciated over five years. Leasehold improvements are amortized over their estimated useful lives or the remaining lease term, whichever is shorter. Construction in progress is capitalized but not depreciated until it is placed into service.

Maintenance and repairs are charged to expense as incurred, while renewals and improvements are capitalized.

Intangible Assets, Finite-Lived, Policy [Policy Text Block]

Intangible Assets

The Company capitalizes payments it makes for licensed products when the payment is based on FDA approval for the product and the cost is recoverable based on expected future cash flows from the product. The cost is amortized on a straight-line basis over the estimated useful life of the product commencing on the approval date in accordance with Accounting Standards Codification (“ASC”) 350 — Intangibles - Goodwill and Other. In November 2021, the Company purchased the rights for its Carglumic Acid product for $3,250 and that cost is being amortized over ten years. A $750 payment related to the approval of Biorphen had been capitalized in 2019 and that cost was being amortized over five years. As a result of the Biorphen sale to Dr. Reddy’s (see Note 14), amortization of that asset was accelerated to record $275 of expense in June 2022 and the remaining $75 of expense in the last six months of the year ended December 31, 2022. A $750 payment related to the approval of Rezipres® had been capitalized in Q1 2022 and that cost was being amortized over five years. As a result of the sale to Dr. Reddy’s, amortization of the Rezipres® asset was accelerated to record the remaining $738 in the three-month period ended June 30, 2022. In September 2022, the Company purchased the rights for its Betaine Anhydrous product for $2,125 and that cost is being amortized over five years. In October 2023, the Company purchased the rights for its Nitisinone product for $650 and that cost is being amortized over five years. The intangible assets, net on the Company’s balance sheet reflected $1,286 of accumulated amortization as of December 31, 2023. The Company recorded $790, $1,617, and $204 of amortization expense for the years ended December 31, 2023, 2022 and 2021 respectively. The table below shows the estimated remaining amortization for these products for each of the five years from 2024 to 2028 and thereafter.

Year	*Amortization Expense*
2024	$	880
2025		880
2026		880
2027		756
2028		423
Thereafter		920
Total estimated amortization expense	$	4,739

Impairment or Disposal of Long-Lived Assets, Policy [Policy Text Block]

Impairment of Long-Lived Assets

Long-lived assets are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. Recoverability of assets to be held and used is measured by a comparison of the carrying amount of an asset to estimated undiscounted future cash flows expected to be generated by the asset. If the carrying amount of an asset exceeds its estimated future cash flows, an impairment charge is recognized in the Company’s statements of operations for the amount by which the carrying amount of the asset exceeds the fair value of the asset. No impairment was recognized during the years ended December 31, 2023, 2022 and 2021.

Debt, Policy [Policy Text Block]

Debt Issuance Costs and Debt Discount and Detachable Debt-Related Warrants

Costs incurred to issue debt are deferred and recorded as a reduction to the debt balance in the accompanying balance sheets. The Company amortizes debt issuance costs over the expected term of the related debt using the effective interest method. Debt discounts relate to the relative fair value of warrants issued in conjunction with the debt and are also recorded as a reduction to the debt balance and accreted over the expected term of the debt to interest expense using the effective interest method.

Lessee, Leases [Policy Text Block]

Leases

The Company accounts for leases in accordance with ASC Topic 842 — Leases. The Company reviews all relevant facts and circumstances of a contract to determine if it is a lease whereby the terms of the agreement convey the right to control the direct use and receive substantially all the economic benefits of an identified asset for a period of time in exchange for consideration. The associated right-of-use assets and lease liabilities are recognized at lease commencement. The Company measures lease liabilities based on the present value of the lease payments over the lease term discounted using the rate it would pay on a loan with the equivalent payments and term for the lease. The Company does not include the impact for lease term options that would extend or terminate the lease unless it is reasonably certain that it will exercise any such options. The Company accounts for the lease components separately from non-lease components for its operating leases.

The Company measures right-of-use assets based on the corresponding lease liabilities adjusted for (i) any prepayments made to the lessor at or before the commencement date, (ii) initial direct costs it incurs, and (iii) any incentives under the lease. In addition, the Company evaluates the recoverability of its right-of-use assets for possible impairment in accordance with its long-lived assets policy.

Operating leases are reflected on the balance sheets as operating lease right-of-use assets, current accrued liabilities and long-term operating lease liabilities. The Company does not have any finance leases as of December 31, 2023 and 2022.

The Company commences recognizing operating lease expense when the lessor makes the underlying asset available for use by the Company and the operating lease expense is recognized on a straight-line basis over the term of the lease. Variable lease payments are expensed as incurred.

The Company does not recognize right-of-use assets or lease liabilities for leases with a term of twelve months or less; such lease costs are recorded in the statements of operations on a straight-line basis over the lease term.

Patent Costs [Policy Text Block]

Patent Costs

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

Concentration Risk, Credit Risk, Policy [Policy Text Block]

Concentrations of Credit Risk, Sources of Supply and Significant Customers

The Company is subject to credit risk for its cash and cash equivalents which are invested in money market funds and U.S. treasury bills from time to time. The Company maintains its cash and cash equivalent balances with one major commercial bank and the deposits held with the financial institution exceed the amount of insurance provided on such deposits and is exposed to credit risk in the event of a default by the financial institutions holding its cash and cash equivalents to the extent recorded on the balance sheets. The Company believes the associated credit risk to be minimal.

The Company is dependent on third-party suppliers for its products and product candidates. In particular, the Company relies, and expects to continue to rely, on a small number of suppliers to manufacture key chemicals, approved products and process its product candidates as part of its development programs. These programs could be adversely affected by a significant interruption in the manufacturing process.

The Company is also subject to credit risk from its accounts receivable related to product sales as it extends credit based on an evaluation of the customer’s financial condition, and collateral is not required. Management monitors its exposure to accounts receivable by periodically evaluating the collectability of the account receivable based on a variety of factors including the length of time the receivables are past due, the financial health of the customer and historical experience. Based upon the review of these factors, the Company recorded no allowance for doubtful accounts at December 31, 2023 or 2022. The accounts receivable balance at December 31, 2023 and 2022 and product sales revenue recognized during the year ended December 31, 2023 and 2022 consist of sales to and amounts due from AnovoRX and Optime Cares for the Company's ALKINDI SPRINKLE®, Carglumic Acid, and Betaine Anhydrous products, as well as from AmerisourceBergen Corporation, Cardinal Health Services and McKesson Corporation for sales of the Company’s Biorphen product. AnovoRx sales made up 78.2% of 2023 total net revenues and 97.4% of net accounts receivable as of December 31, 2023, and 45.5% of 2022 total net revenues and 79.8% of net accounts receivable as of December 31, 2022.

Revenue from Contract with Customer [Policy Text Block]

Revenue Recognition for Contracts with Customers

The Company accounts for contracts with its customers in accordance with ASC 606 — Revenue from Contracts with Customers. ASC 606 applies to all contracts with customers, except for contracts that are within the scope of other standards. Under ASC 606, an entity recognizes revenue when its customer obtains control of promised goods or services, in an amount that reflects the consideration which the entity expects to receive in exchange for those goods or services. To determine revenue recognition for arrangements that an entity determines are within the scope of ASC 606, the entity performs the following five steps: (i) identify the contract(s) with a customer; (ii) identify the performance obligations in the contract; (iii) determine the transaction price; (iv) allocate the transaction price to the performance obligations in the contract; and (v) recognize revenue when (or as) the entity satisfies a performance obligation.

At contract inception, once the contract is determined to be within the scope of ASC 606, the Company assesses the goods or services promised within each contract and determines those that are performance obligations and assesses whether each promised good or service is distinct. The Company then recognizes as revenue the amount of the transaction price that is allocated to the respective performance obligation when (or as) the performance obligation is satisfied. Arrangements that include rights to additional goods or services that are exercisable at a customer’s discretion are generally considered options. The Company assesses whether these options provide a material right to the customer and, if so, they are considered performance obligations. The exercise of a material right is accounted for as a contract modification for accounting purposes.

The Company recognizes as revenue the amount of the transaction price that is allocated to the respective performance obligation when (or as) each performance obligation is satisfied at a point in time or over time, and if over time this is based on the use of an output or input method. Any amounts received prior to revenue recognition will be recorded as deferred revenue. Amounts expected to be recognized as revenue within the twelve months following the balance sheet date will be classified as current portion of deferred revenue in the Company’s balance sheets. Amounts not expected to be recognized as revenue within the twelve months following the balance sheet date are classified as long-term deferred revenue, net of current portion.

Milestone Payments – If a commercial contract arrangement includes development and regulatory milestone payments, the Company will evaluate whether the milestone conditions have been achieved and if it is probable that a significant revenue reversal would not occur before recognizing the associated revenue. Milestone payments that are not within the Company’s control or the licensee’s control, such as regulatory approvals, are generally not considered probable of being achieved until those approvals are received.

Royalties – For arrangements that include sales-based royalties, including milestone payments based on a level of sales, which are the result of a customer-vendor relationship and for which the license is deemed to be the predominant item to which the royalties relate, the Company will recognize revenue at the later of (i) when the related sales occur, or (ii) when the performance obligation to which some or all of the royalty has been allocated has been satisfied or partially satisfied.

Significant Financing Component – In determining the transaction price, the Company will adjust consideration for the effects of the time value of money if the expected period between payment by the licensees and the transfer of the promised goods or services to the licensees will be more than one year.

The Company sells its ALKINDI SPRINKLE®, Carglumic Acid, Betaine Anhydrous, and Nisitinone products to pharmacy distributor customers which provide order fulfilment and inventory storage/distribution services. The Company may sell products in the U.S. to wholesale pharmaceutical distributors, who then sell the product to hospitals and other end-user customers. Sales to wholesalers are made pursuant to purchase orders subject to the terms of a master agreement, and delivery of individual shipments represent performance obligations under each purchase order. The Company uses a third-party logistics (“3PL”) vendor to process and fulfill orders and has concluded it is the principal in the sales to wholesalers because it controls access to the 3PL vendor services rendered and directs the 3PL vendor activities. The Company has no significant obligations to wholesalers to generate pull-through sales.

For its ALKINDI SPRINKLE®, Carglumic Acid, Betaine Anhydrous, and Nitisinone products, the Company bills at the initial product list price which are subject to offsets for patient co-pay assistance and potential state Medicaid reimbursements which are estimated and recorded as a reduction of net revenues at the date of sale/shipment. Selling prices initially billed to wholesalers are subject to discounts for prompt payment and subsequent chargebacks when the wholesalers sell products at negotiated discounted prices to members of certain group purchasing organizations (“GPOs”) and government programs. Because of the shelf life of the product and the Company’s lengthy return period, there may be a significant period of time between when the product is shipped and when it issues credits on returned product.

The Company estimates the transaction price when it receives each purchase order taking into account the expected reductions of the selling price initially billed to the wholesaler/distributor arising from all of the above factors. The Company has developed estimates for future returns and chargebacks and the impact of other discounts and fees it pays. When estimating these adjustments to the transaction price, the Company reduces it sufficiently to be able to assert that it is probable that there will be no significant reversal of revenue when the ultimate adjustment amounts are known.

The Company stores its ALKINDI SPRINKLE®, Carglumic Acid, Betaine Anhydrous, and Nitisinone inventory at its pharmacy distributor customer locations, and sales are recorded when stock is pulled and shipped to fulfill specific patient orders. The Company may recognize revenue and cost of sales from products sold to wholesalers upon delivery to the wholesaler location. At that time, the wholesalers take control of the product as they take title, bear the risk of loss of ownership and have an enforceable obligation to pay the Company. They also have the ability to direct sales of product to their customers on terms and at prices they negotiate. Although wholesalers have product return rights, the Company does not believe they have a significant incentive to return the product.

Upon recognition of revenue from product sales, the estimated amounts of credit for product returns, chargebacks, distribution fees, prompt payment discounts, state Medicaid and GPO fees are included in sales reserves, accrued liabilities and net accounts receivable. The Company monitors actual product returns, chargebacks, discounts and fees subsequent to the sale. If these amounts end up differing from its estimates, it will make adjustments to these allowances, which are applied to increase or reduce product sales revenue and earnings in the period of adjustment.

Cost of Goods and Service [Policy Text Block]

Cost of Product Sales

Cost of product sales consists of the profit-sharing and royalty fees with the Company’s product licensing and development partners, the purchase costs for finished products from third-party manufacturers, the amortization of certain intangible assets, and freight and handling/storage costs from the Company’s 3PL logistics service providers. The cost of sales for profit-sharing and royalty fees and costs for purchased finished products and the associated inbound freight expense is recorded when the associated product sale revenue is recognized in accordance with the terms of shipment to customers while outbound freight and handling/storage fees charged by the 3PL service provider are expensed as they are incurred. Cost of sales also reflects any write-downs or reserve adjustments for the Company’s inventories.

Research and Development Expense, Policy [Policy Text Block]

Research and Development Expenses

Research and development (“R&D”) expenses include both internal R&D activities and external contracted services. Internal R&D activity expenses include salaries, benefits and stock-based compensation and other costs to support the Company’s R&D operations. External contracted services include product development efforts such as certain product licensor milestone payments, clinical trial activities, manufacturing and control-related activities and regulatory costs. R&D expenses are charged to operations as incurred. The Company reviews and accrues R&D expenses based on services performed and relies upon estimates of those costs applicable to the stage of completion of each project. Significant judgments and estimates are made in determining the accrued balances at the end of any reporting period. Actual results could differ from the Company’s estimates.

Upfront payments and milestone payments made for the licensing of technology for products that are not yet approved by the FDA are expensed as R&D in the period in which they are incurred. Nonrefundable advance payments for goods or services to be received in the future for use in R&D activities are recorded as prepaid expenses and are expensed as the related goods are delivered or the services are performed.

Earnings Per Share, Policy [Policy Text Block]

Income (Loss) Per Share

Basic net income (loss) per common share is computed by dividing net income (loss) attributable to common stockholders for the period by the weighted average number of common shares outstanding during the period. Diluted net income (loss) per share is computed by dividing the net income (loss) attributable to common stockholders for the period by the weighted average number of common and common equivalent shares, such as Series A Preferred, unvested restricted stock, stock options and warrants that are outstanding during the period. Common stock equivalents are excluded from the computation when their inclusion would be anti-dilutive. No such adjustments were made for 2023, 2022 or 2021 as the Company reported a net loss for the years ended December 31, 2023, 2022 and 2021 and including the effects of common stock equivalents in the diluted earnings per share calculation would have been anti-dilutive (see Note 9).

Share-Based Payment Arrangement [Policy Text Block]

Stock-Based Compensation

The Company accounts for stock-based compensation under the provisions of ASC 718 Compensation – Stock Compensation. The guidance under ASC 718 requires companies to estimate the fair value of the stock-based compensation awards on the date of grant and record expense over the related service periods, which are generally the vesting period of the equity awards. Compensation expense is recognized over the period during which services are rendered by consultants and non-employees until completed. At the end of each financial reporting period prior to completion of the service, the fair value of these awards is remeasured using the then-current fair value of our common stock and updated assumption inputs in the Black-Scholes option-pricing model (“BSM”).

The Company estimates the fair value of stock-based option awards using the BSM. The BSM requires the input of subjective assumptions, including the expected stock price volatility, the calculation of expected term, forfeitures and the fair value of the underlying common stock on the date of grant, among other inputs. The risk-free interest rate was determined from the implied yields for zero-coupon U.S. government issues with a remaining term approximating the expected life of the options or warrants. Dividends on common stock are assumed to be zero for the BSM valuation of the stock options. The expected term of stock options granted is based on vesting periods and the contractual life of the options. Expected volatilities are based on the Company's historical volatility subsequent to our IPO, which we believe represents the most accurate basis for estimating expected future volatility under the current conditions. The Company accounts for forfeitures as they occur.

Income Tax, Policy [Policy Text Block]

Income Taxes

As part of the process of preparing the Company’s financial statements, the Company must estimate the actual current tax liabilities and assess temporary differences resulting from differing treatment of items for tax and accounting purposes. These differences result in deferred tax assets and liabilities, which are included within the balance sheets. The Company must assess the likelihood that the deferred tax assets will be recovered from future taxable income and, to the extent the Company believes that recovery is not likely, a valuation allowance must be established. To the extent the Company establishes a valuation allowance or increase or decrease to this allowance in a period, the impact will be included in income tax expense in the statements of operations. As of December 31, 2023 and 2022, the Company has established a 100% valuation reserve against its deferred tax assets.

The Company accounts for income taxes under the provisions of ASC 740 - Income Taxes. As of December 31, 2023 and 2022, there were no unrecognized tax benefits included in the balance sheets that would, if recognized, affect the effective tax rate. The Company’s practice is to recognize interest and penalties related to income tax matters in income tax expense. The Company had no accrual for interest or penalties in its balance sheets at December 31, 2023 or 2022, and has not recognized interest and penalties in the statements of operations for the years ended December 31, 2023, 2022 and 2021. As of December 31, 2023, the Company is subject to taxation in the United States and certain individual states – primarily Illinois and Tennessee. The Company’s tax losses from 2017 through 2023 are subject to examination by the federal and state tax authorities due to the carryforward of unutilized net operating losses (“NOLs”).

Current accounting standards include guidance on the accounting for uncertainty in income taxes recognized in the financial statements. Such standards also prescribe a recognition threshold and measurement model for the financial statement recognition of a tax position taken, or expected to be taken, and provides guidance on derecognition, classification, interest and penalties, accounting in interim periods, disclosure and transition. The Company believes that the ultimate deductibility of all tax positions is highly certain, although there is uncertainty about the timing of such deductibility. As a result, no liability for uncertain tax positions was recorded as of December 31, 2023 or 2022.

Fair Value Measurement, Policy [Policy Text Block]

Fair Value Measurements

We measure certain of our assets and liabilities at fair value. Fair value represents the price 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. Fair value accounting requires characterization of the inputs used to measure fair value into a three-level fair value hierarchy as follows:

Level 1 – Inputs based on quoted prices in active markets for identical assets or liabilities. An active market is a market in which transactions occur with sufficient frequency and volume to provide pricing information on an ongoing basis.

Level 2 – Observable inputs that reflect the assumptions market participants would use in pricing the asset or liability developed based on market data obtained from sources independent from the entity.

Level 3 – Unobservable inputs that reflect the entity’s own assumptions about the assumptions market participants would use in pricing the asset or liability developed based on the best information available.

Fair value measurements are classified based on the lowest level of input that is significant to the measurement. The Company’s assessment of the significance of a particular input to the fair value measurement requires judgment, which may affect the valuation of the assets and liabilities and their placement within the fair value hierarchy levels. The determination of the fair values stated below takes into account the market for the Company’s financials, assets and liabilities, the associated credit risk and other factors as required. The Company considers active markets as those in which transactions for the assets or liabilities occur in sufficient frequency and volume to provide pricing information on an ongoing basis.

The Company’s financial instruments included cash and cash equivalents, accounts receivable, accounts payable, accrued liabilities and long-term debt obligation. The carrying amounts of these financial instruments, except for the long-term debt obligation, approximate their fair values due to the short-term maturities of these instruments. Based on borrowing rates currently available to the Company, the carrying value of the long-term debt obligation approximate its fair value.

New Accounting Pronouncements, Policy [Policy Text Block]

Impact of Recent Accounting Pronouncements

In March 2020, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update ("ASU") No. 2020-04, Reference Rate Reform (Topic 848): Facilitation of the Effects of Reference Rate Reform on Financial Reporting and in January 2021, the FASB issued ASU No. 2021-01, Reference Rate Reform (Topic 848): Scope ("ASU 2021-01"). Both ASU No. 2020-04 and ASU No. 2021-01 provide optional expedients and exceptions for applying GAAP to contracts, hedging relationships, and other transactions that reference the London Interbank Offered Rate ("LIBOR") or another reference rate expected to be discontinued because of reference rate reform. ASU No. 2020-04 and ASU No. 2021-01 are effective upon issuance for contract modifications and hedging relationships, and the Company is allowed to elect to apply the amendments prospectively through December 31, 2022. In December 2022, the FASB issued ASU No. 2022-06, Reference Rate Reform (Topic 848): Deferral of the Sunset Date of Topic 848, which extends the temporary accounting rules under Topic 848 to December 31, 2024. The Company transitioned to the secured overnight financing rate ("Term SOFR") from LIBOR on August 22, 2023. There are no material impacts to the consolidated financial statements.

In June 2016, the FASB issued ASU 2016-13, Financial Instruments-Credit Losses (Topic 316): Measurement of Credit Losses on Financial Instruments, which modifies the measurement and recognition of credit losses for most financial assets and certain other instruments. The new standard requires the use of forward-looking expected credit loss models based on historical experience, current conditions, and reasonable and supportable forecasts that affect the collectability of the reported amount, which may result in earlier recognition of credit losses under the new standard. The new guidance also modifies the impairment models for available-for-sale debt securities and for purchased financial assets with credit deterioration since their origination. Subsequent to the issuance of ASU No. 2016-13, the FASB issued ASU No. 2018-19, Codification Improvements to Topic 326, Financial Instruments-Credit Losses. This ASU does not change the core principle of the guidance in ASU No. 2016-13, instead these amendments are intended to clarify and improve operability of certain topics included within the credit losses standard. The FASB also subsequently issued ASU No. 2019-04 which did not change the core principle of the guidance in ASU No. 2016-13 but clarified that expected recoveries of amounts previously written off and expected to be written off should be included in the valuation account and should not exceed amounts previously written off and expected to be written off. The Company prospectively adopted this guidance on the effective date of January 1, 2023 and the adoption did not have a material impact to the consolidated financial statements and resulted in no adjustment to the Company’s prior year earnings.

Note 2 - Liquidity Considerations

12 Months Ended

Dec. 31, 2023

Liquidation Basis of Accounting [Text Block]

Note 2 — Liquidity Considerations

As of December 31, 2023, the Company had an accumulated deficit of $104,070 and for the year ended December 31, 2023 the Company had a net loss of $936.

To date, the Company has generated revenues from multiple products and expects further growth in 2024 and beyond in accordance with additional market penetration from these products plus revenues from additional products where it anticipates FDA approval. The Company currently believes its existing cash and cash equivalents of $21,388 as of December 31, 2023 will be sufficient to fund its operating expenses and capital expenditure requirements for at least the next twelve months from the date of issuance of these financial statements. This estimate is based on the Company’s current assumptions, including assumptions relating to estimated sales and its ability to manage its spending. The Company could use its available capital resources sooner than currently expected. Accordingly, the Company could seek to obtain additional capital through equity financings, the issuance of debt or other arrangements. However, there can be no assurance that the Company will be able to raise additional capital if needed or under acceptable terms, if at all. The sale of additional equity may dilute existing stockholders and newly issued shares may contain senior rights and preferences compared to currently outstanding common shares. The Company’s existing long-term debt obligation contains covenants and limits the Company’s ability to pay dividends or make other distributions to stockholders. If the Company experiences delays in product sales growth and completing its product development and obtaining regulatory approval for its other product candidates and is unable to obtain such additional financing, operations would need to be scaled back or discontinued.

Note 12 - Income Taxes (Details Textual) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Percentage for Valuation Reserve Against Deferred Tax Assets	100.00%	100.00%
Deferred Tax Assets, Gross	$ 21,516	$ 21,632
Operating Loss Carryforwards	54,190
Deferred Tax Assets, Operating Loss Carryforwards, Not Subject to Expiration	$ 54,190

Note 4 - Property and Equipment (Details Textual) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Depreciation	$ 44	$ 66	$ 155

Note 3 - Summary of Significant Accounting Policies

12 Months Ended

Dec. 31, 2023

Significant Accounting Policies [Text Block]

Note 3 — Summary of Significant Accounting Policies

Basis of Presentation

The Company has prepared the accompanying financial statements in accordance with GAAP.

Use of Estimates

Segment Information

Cash and Cash Equivalents

Accounts Receivable

Inventories

Property and Equipment

Maintenance and repairs are charged to expense as incurred, while renewals and improvements are capitalized.

Intangible Assets

Year	*Amortization Expense*
2024	$	880
2025		880
2026		880
2027		756
2028		423
Thereafter		920
Total estimated amortization expense	$	4,739

Impairment of Long-Lived Assets

Debt Issuance Costs and Debt Discount and Detachable Debt-Related Warrants

Leases

Patent Costs

Concentrations of Credit Risk, Sources of Supply and Significant Customers

Revenue Recognition for Contracts with Customers

Cost of Product Sales

Research and Development Expenses

Income (Loss) Per Share

Stock-Based Compensation

Income Taxes

Fair Value Measurements

Impact of Recent Accounting Pronouncements

Note 5 - Debt

12 Months Ended

Dec. 31, 2023

Long-Term Debt [Text Block]

Note 5 – Debt

SWK Loan

In November 2019, the Company entered into a credit agreement (the “SWK Credit Agreement”) with SWK Holdings Corporation (“SWK”) which provided for up to $10,000 in debt financing. The Company received proceeds of $5,000 at closing and was able to borrow an additional $5,000 upon the FDA approval of a second product developed by the Company, excluding EM-100. In March 2020, in conjunction with the Company’s ALKINDI SPRINKLE® product licensing agreement (see Note 14) and the Company’s March 2020 sale of shares of its common stock (see Note 6), the Company and SWK amended the SWK Credit Agreement. The amendment provided the Company with the option to immediately draw an additional $2,000 and the ability to borrow up to another $3,000 based upon the FDA approval of EM-100 and ALKINDI SPRINKLE® which subsequently occurred in September 2020. Accordingly, the Company borrowed an additional $2,000 in August 2020. Under the terms of the SWK Credit Agreement, the Company was required to maintain a minimum cash balance of $3,000, and pay 5.5% of the loan principal balance commencing in February 2022 and then every three months thereafter until November 2024 at which time the remaining principal balance is due. Borrowings under the SWK Credit Agreement are secured by the Company’s assets. The SWK Credit Agreement contains customary default provisions and covenants which include limits on additional indebtedness. In February 2021, the Company notified SWK that it will not require additional borrowing capacity under the SWK Credit Agreement and terminated the additional borrowing capacity with SWK.

In connection with the initial $5,000 borrowed in November 2019, the Company issued warrants to SWK to purchase 51,239 shares of the Company’s common stock with an exercise price of $5.86 per share. The relative fair value of these 51,239 warrants was $226 and was estimated using the Black-Scholes-Merton option pricing model with the following assumptions: fair value of the Company’s common stock at issuance of $5.75 per share; seven-year contractual term; 95% volatility; 0% dividend rate; and a risk-free interest rate of 1.8%.

In connection with the additional $2,000 borrowed in August 2020, the Company issued warrants for 18,141 shares of its common stock at an exercise price of $6.62 per share. The relative fair value of the 18,141 warrants was $94 and was estimated using the Black-Scholes-Merton option pricing model with the following assumptions: fair value of the Company’s common stock at issuance of $6.85 per share; seven-year contractual term; 95% volatility; 0% dividend rate; and a risk-free interest rate of 0.4%.

These warrants (the “SWK Warrants”) are exercisable immediately and have a term of seven years from the date of issuance. The SWK Warrants are subject to a cashless exercise feature, with the exercise price and number of shares issuable upon exercise subject to adjustment in connection with stock splits, dividends, reclassifications and other conditions.

In April 2022, the Company and SWK entered into an amendment to the SWK Credit Agreement which allowed for a deferral of loan principal payments until May 2023 and reduced the interest rate to LIBOR 3-month plus 8.0%, subject to a stated LIBOR floor rate of 2.0%. In accordance with the change, the Company has classified $1,033 as principal due in the next 12 months and the remainder classified as long-term debt in its balance sheet at December 31, 2022. Because LIBOR was phased out as of June 2023, the Company amended the Credit Agreement in August 2023 to refer to Term SOFR, with an interest rate of Term SOFR plus 8.26%, subject to a stated Term SOFR floor rate of 5.0%.

The Company recorded interest expense of $1,060, $955 and $1,042 in 2023, 2022 and 2021, respectively, which included $117, $127 and $148, respectively, of debt discount amortization. The Company had accrued interest of $332 and $231 as of December 31, 2023 and 2022, respectively, which is included in accrued liabilities in the accompanying balance sheets.

Note 5 – Debt (continued)

The table below reflects the future annual payments for the SWK loan principal and interest as of December 31, 2023.

	*Amount*
2024		6,483
Total payments		6,483
Less: amount representing interest		(1,023	)
Loan payable, gross		5,460
Less: unamortized discount		(80	)
Debt, net of unamortized discount	$	5,380

PPP loan

On May 4, 2020, the Company received $361 in loan proceeds under the Paycheck Protection Program (“PPP”) from the Small Business Administration (“SBA”) through its banking relationship with Bank of America. On May 20, 2021, the Company received notice that the loan principal and cumulative interest of $4 was forgiven in full as permitted under the applicable SBA guidelines for PPP loans. The $365 gain on debt extinguishment is reflected in non-operating income for the year ended December 31, 2021.

EIDL loan

On July 21, 2020, the Company received $150 in loan proceeds under the Economic Injury Disaster Loan program (“EIDL”) from the SBA. The Company paid off the full EIDL loan principal and its cumulative interest of $6 in July 2021.

Note 7 - Common Stock Warrants (Tables)

12 Months Ended

Dec. 31, 2023

Schedule of Stockholders' Equity Note, Warrants or Rights [Table Text Block]

Description of Warrants	*No. of Shares*		*Exercise Price*
SWK Warrants – Debt (Tranche #1)		51,239	$	5.86
SWK Warrants – Debt (Tranche #2)		18,141	$	6.62
Total		69,380	6.05 (Avg)

Schedule of Rollforward of Warrants Outstanding [Table Text Block]

	*No. of Shares*
Balance as of the beginning of the year		483,380
Expiration of National Securities Corp – November 2018 issuance		(414,000	)
Balance as of the end of the year		69,380

Note 3 - Summary of Significant Accounting Policies - Schedule of Intangible Assets Amortization Expense (Details) $ in Thousands	Dec. 31, 2023 USD ($)
2024	$ 880
2025	880
2026	880
2027	756
2028	423
Thereafter	920
Total estimated amortization expense	$ 4,739

Note 8 - Share-based Payment Awards - Schedule of Stock Option Activity (Details) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2023 USD ($) $ / shares shares
Balance, Options (in shares) \| shares	4,402,292
Outstanding, Weighted Average Exercise Price (in dollars per share) \| $ / shares	$ 4.71
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Gross (in shares) \| shares	1,108,291
Issued, Weighted Average Exercise Price (in dollars per share) \| $ / shares	$ 3.51
Exercised, Options (in shares) \| shares	(407,808)
Exercised, Weighted Average Exercise Price (in dollars per share) \| $ / shares	$ 2.23
Forfeited/Cancelled, Options (in shares) \| shares	(263,549)
Forfeited/Cancelled, Weighted Average Exercise Price (in dollars per share) \| $ / shares	$ 5.94
Balance, Options (in shares) \| shares	4,839,226
Outstanding, Weighted Average Exercise Price (in dollars per share) \| $ / shares	$ 4.57
Outstanding, Weighted Average Remaining Contractual Term (Year)	7 years 3 months 18 days
Outstanding, Aggregate Intrinsic Value \| $	$ 3,467
Exercisable, Options (in shares) \| shares	3,399,896
Exercisable, Weighted Average Exercise Price (in dollars per share) \| $ / shares	$ 4.78
Exercisable, Weighted Average Remaining Contractual Term (Year)	6 years 8 months 12 days
Options exercisable at December 31, 2023 \| $	$ 2,432
Vested and expected to vest, Options (in shares) \| shares	4,839,226
Vested and expected to vest, Weighted Average Exercise Price (in dollars per share) \| $ / shares	$ 4.57
Vested and expected to vest, Weighted Average Remaining Contractual Term (Year)	7 years 3 months 18 days
Vested and expected to vest, Aggregate Intrinsic Value \| $	$ 3,467

Note 11 - Leases

12 Months Ended

Dec. 31, 2023

Lessee, Operating Leases [Text Block]

Note 11 — Leases

The Company recognizes a right-of-use (“ROU”) asset and a lease liability on the balance sheet for substantially all leases, including operating leases, and separates lease components from non-lease components related to its office space lease.

In January 2018, the Company signed an amended lease agreement to lease additional office space adjacent to its current corporate office space in Deer Park, Illinois. In October 2020, the Company renewed its office lease for a two-year period through March 2023 and recorded $195 in ROU assets and $195 in operating lease liabilities in association with the lease extension. In November 2022, the Company renewed its office lease for a two-year period through March 2025 and recorded $188 in ROU assets and $188 in operating lease liabilities in association with the lease extension.

In March 2018, the Company entered into a lease for laboratory space at a complex in Lake Zurich, Illinois. The lease commenced in March 2018. In November 2020, this laboratory lease was extended to June 2021 and was not extended after that date as the Company completed an evaluation its laboratory operations requirements and determined it would discontinue the laboratory activities and outsource its requirements.

The Company does not have any lease contracts that contain: (1) an option to extend that the Company is reasonably certain to exercise, (2) an option to terminate that the Company is reasonably certain to exercise, or (3) an option to extend (or not to terminate) in which exercise of the option is controlled by the lessor. Additionally, the Company does not have any leases with residual value guarantees or material restrictive covenants. Lease liabilities and their corresponding right-of-use assets have been recorded based on the present value of the future lease payments over the expected lease term. One of the Company’s lease agreements contains provisions for escalating rent payments over the term of the lease.

The Company’s leases do not contain readily determinable implicit discount rates, and therefore, the Company was required to use its incremental borrowing rate of 7.8% to discount the future lease payments based on information available at lease commencement. In October 2020, the new discount rate for the office lease extension was estimated at 5.4%. In November 2022, the new discount rate for an additional office lease extension was estimated at 8.6%. The incremental borrowing rate was estimated by determining the rate of interest that the Company would have to pay to borrow on a collateralized basis over a similar term an amount equal to the lease payments in a similar economic environment.

Note 11 — Leases (continued)

The Company’s operating lease cost as presented in the “Research and Development” and “General and Administrative” captions in the statements of operations was $0, $0, and $9 and $67, $82, and $86 for the years ended December 31, 2023, 2022 and 2021, respectively. For the years ended December 31, 2023, 2022 and 2021, the Company recorded $77, $86, and $113, respectively, in rent expense. Cash paid for amounts included in the measurement of operating lease liabilities was $88, $88, and $83 for the years ended December 31, 2023, 2022, and 2021, respectively. The ROU asset amortization for years ended December 31, 2023, 2022 and 2021 was $67, $62, and $88, respectively, and is reflected in depreciation and amortization in the Company’s statements of cash flows. As of December 31, 2023, the weighted-average remaining lease term was 1.25 years, and the weighted-average discount rate was 8.6%.

The table below presents the lease-related assets and liabilities recorded on the balance sheet as of December 31, 2023:

Assets	*Classification*
Operating lease right-of-use assets	Operating lease right-of-use assets, net	$	92
Total leased assets		$	92
Liabilities
Operating lease liabilities, current	Accrued liabilities	$	53
Operating lease liabilities, noncurrent	Operating lease liabilities, net of current portion		22
Total operating lease liabilities		$	75

The Company’s future annual lease commitments as of December 31, 2023 are as indicated below:

	*Total*			*2024*		*2025*		*2026*
Undiscounted lease payments	$	81		$	58	$	23	$	—
Less: Imputed interest		(6	)
Total lease liabilities	$	75

Note 8 - Share-based Payment Awards (Details Textual) - USD ($) $ / shares in Units, $ in Thousands		1 Months Ended		12 Months Ended
	Dec. 31, 2018	Apr. 30, 2021	Jul. 31, 2017	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Jan. 01, 2023	Jan. 01, 2022	Jan. 01, 2021	Dec. 31, 2020	May 30, 2017
Common Stock, Capital Shares Reserved for Future Issuance, Increase (in shares)							1,014,124	985,040	972,512
Common Stock, Shares, Outstanding (in shares)				25,688,062	25,353,119	24,626,004	25,353,119			24,312,808
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Gross (in shares)				1,108,291
Share-Based Payment Arrangement, Expense				$ 3,137	$ 4,218	$ 3,381
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Exercises in Period, Intrinsic Value				$ 612
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Exercises in Period (in shares)				407,808
Proceeds from Stock Options Exercised				$ 149	$ 35
Share-Based Payment Arrangement, Nonvested Award, Option, Cost Not yet Recognized, Amount				$ 3,601
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value (in dollars per share)					$ 2
Stock Issued During Period, Shares, Employee Stock Purchase Plans (in shares)		25,000		86,782	69,884
General and Administrative Expense [Member]
Class of Warrant or Right, Modification Expense					$ 244
Share-Based Payment Arrangement, Expense				$ 2,864	3,954	2,838
Research and Development Expense [Member]
Share-Based Payment Arrangement, Expense				$ 273	264	543
Consultant [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Expiration Period (Year)				5 years
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Gross (in shares)			50,000
Executive Officer [Member]
Share-Based Payment Arrangement, Option, Exercise Price Range, Lower Range Limit (in dollars per share)				$ 1.37
Share-Based Payment Arrangement, Option, Exercise Price Range, Upper Range Limit (in dollars per share)				$ 8.61
Executive Officer [Member] \| General and Administrative Expense [Member]
Class of Warrant or Right, Modification Expense				$ 104
Share-Based Payment Arrangement, Option [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Expiration Period (Year)				10 years
Restricted Stock Units (RSUs) [Member]
Share-Based Payment Arrangement, Expense				$ 239	$ 114
Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount				$ 608
Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition (Year)				2 years 6 months
The 2017 Plan [Member] \| Common Stock [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Shares Authorized (in shares)											5,000,000
The 2018 Plan [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Shares Available for Grant (in shares)				663,598
Share-based Compensation Arrangement by Share-based Payment Award, Annual Increase in Share Reserve as a Percent of Outstanding Common Stock				4.00%
The Two Thousand Eighteen Equity Incentive Plan Member
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Exercises in Period (in shares)				207,626	25,000
The 2018 Employee Stock Purchase Plan [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Shares Available for Grant (in shares)				623,514
Common Stock, Capital Shares Reserved for Future Issuance, Increase (in shares)	150,000
Share-Based Payment Arrangement, Expense				$ 135	$ 128	$ 73
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value (in dollars per share)				$ 1.27	$ 1.17	$ 2.5
Common Stock, Capital Shares Reserved for Future Issuance (in shares)	150,000
Common Stock, Capital Shares Reserved for Future Issuance, Percentage Increase	1.00%
Employee Stock Purchase Plans, Fair Value of Common Stock Price Per Share on Offering Date, Percentage	85.00%
Employee Stock Purchase Plans, Fair Value of Common Stock Price Per Share on Purchase Date, Percentage	85.00%
Stock Issued During Period, Shares, Employee Stock Purchase Plans (in shares)				86,782	69,884
Employee Stock Purchase Plan (ESPP), Cash Contributions to ESPP				$ 230	$ 174
The 2018 Employee Stock Purchase Plan [Member] \| Accrued Liabilities [Member]
Employee-related Liabilities, Current				$ 24	$ 23

Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Current assets:
Cash and cash equivalents	$ 21,388	$ 16,305
Accounts receivable, net	3,411	1,852
Inventories	911	557
Prepaid expenses and other current assets	1,129	1,290
Total current assets	26,839	20,004
Property and equipment, net	58	72
Intangible assets, net	4,739	4,754
Operating lease right-of-use assets, net	92	188
Other long-term assets, net	12	12
Total assets	31,740	25,030
Current liabilities:
Accounts payable	1,848	1,766
Current portion of long-term debt, net of discount	5,380	1,033
Accrued liabilities	9,013	3,662
Total current liabilities	16,241	6,461
Long-term debt, net of discount and including accrued fees	0	5,384
Operating lease liabilities, net of current portion	22	107
Total liabilities	16,263	11,952
Commitments and contingencies (Note 14)
Stockholders’ equity
Common stock, $0.001 par value; 50,000,000 shares authorized; 25,688,062 and 25,353,119 shares issued and outstanding at December 31, 2023 and 2022, respectively	26	25
Additional paid-in capital	119,521	116,187
Accumulated deficit	(104,070)	(103,134)
Total stockholders’ equity	15,477	13,078
Total liabilities and stockholders’ equity	$ 31,740	$ 25,030

Note 12 - Income Taxes

12 Months Ended

Dec. 31, 2023

Income Tax Disclosure [Text Block]

Note 12 – Income Taxes

The provision for income taxes for the Company consists of the following for the years ended December 31, 2023, 2022 and 2021:

	*Year ended*			*Year ended*			*Year ended*
	*December 31,*			*December 31,*			*December 31,*
	*2023*			*2022*			*2021*
Current:
Federal	$	61		$	—		$	—
State		186			—			—
Total current expense		247			—			—

Deferred:
Federal		(85	)		2,272			460
State		(31	)		812			185
Change in valuation allowance		116			(3,084	)		(645	)
Total deferred expense		—			—			—
Total provision	$	247		$	—		$	—

Deferred income taxes reflect the net tax effects of temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes.

Note 12 – Income Taxes (continued)

The significant components of the Company’s deferred tax assets as of December 31, 2023 and 2022 are as follows:

	*December 31,*			*December 31,*
	*2023*			*2022*
Net operating losses	$	15,447		$	17,183
Stock-based expenses		3,372			3,090
Accruals and other		2,697			1,359
Total deferred tax assets		21,516			21,632
Valuation allowance		(21,516	)		(21,632	)
Net deferred tax assets	$	—		$	—

Based on the uncertainty of future taxable income at this time management believes a 100% valuation reserve for the $21,516 and $21,632 deferred tax assets at December 31, 2023 and 2022, respectively, is appropriate.

A reconciliation of the statutory federal tax rate to effective tax rate is shown below:

	*Year ended*			*Year ended*			*Year ended*
	*December 31,*			*December 31,*			*December 31,*
	*2023*			*2022*			*2021*
Provision (benefit) at statutory rate		21.0	%		(21.0	)%		(21.0	)%
Permanent items (primarily warrants and stock compensation)		39.1			(3.3	)		(2.5	)
State tax benefit		6.5			(8.7	)		(9.5	)
Federal rate change		—			—			—
Other items		—			—			—
Increase (decrease) in valuation allowance		(30.7	)		33.0			33.0
Income tax expense		35.9	%		—	%		—	%

The Company has a federal and state NOL carryforward of $54,190 as of December 31, 2023. Under the Tax Act, federal NOLs incurred in taxable years ending after December 31, 2017 in the amount of $54,190 may be carried forward indefinitely and are subject to an 80% usage limitation. The state NOL carry forward will begin to expire in 2029.

In addition, under Sections 382 and 383 of the Internal Revenue Code of 1986, as amended, and corresponding provisions of state law, if a corporation undergoes an “ownership change,” which is generally defined as a greater than 50% change (by value) in its equity ownership over a three-year period, the corporation’s ability to use its pre-change NOL carryforwards and other pre-change tax attributes (such as research tax credits) to offset its post-change income may be limited.

The entire disclosure for income taxes. Disclosures may include net deferred tax liability or asset recognized in an enterprise's statement of financial position, net change during the year in the total valuation allowance, approximate tax effect of each type of temporary difference and carryforward that gives rise to a significant portion of deferred tax liabilities and deferred tax assets, utilization of a tax carryback, and tax uncertainties information.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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Reference 4: http://www.xbrl.org/2003/role/disclosureRef
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Reference 10: http://www.xbrl.org/2003/role/disclosureRef
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SWK Credit Agreement [Member]

Note 5 - Debt (Tables)

12 Months Ended

Dec. 31, 2023

Schedule of Maturities of Long-Term Debt [Table Text Block]

	*Amount*
2024		6,483
Total payments		6,483
Less: amount representing interest		(1,023	)
Loan payable, gross		5,460
Less: unamortized discount		(80	)
Debt, net of unamortized discount	$	5,380

Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
Statements of Cash Flows - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Cash flows from operating activities
Net income (loss)	$ (936)	$ (9,021)	$ (1,955)
Adjustments to reconcile net loss to net cash provided by (used in) operating activities:
Stock-based compensation	3,137	4,218	3,381
Depreciation and amortization	901	1,774	462
Debt discount amortization	117	127	148
Gain on forgiveness of PPP loan	0	0	(365)
Gain on sale of equipment	0	0	(181)
Changes in operating assets and liabilities:
Accounts receivable	(1,559)	3,619	(5,423)
Inventories	(354)	(7)	692
Prepaid expenses and other assets	161	1,902	(1,026)
Accounts payable	53	(8)	(570)
Accrued liabilities	5,295	2,217	116
Net cash provided by (used in) operating activities	6,815	4,821	(4,721)
Cash used in investing activities
Proceeds from sale of equipment	0	0	700
Purchases of property and equipment	0	(38)	(9)
Purchase of product licensing rights	(775)	(2,750)	(3,250)
Net cash used in investing activities	(775)	(2,788)	(2,559)
Cash flows from financing activities
Debt paydown	(1,155)	(385)	(150)
Net proceeds from employee stock purchase plan and stock option and stock warrant exercises	198	251	541
Net cash (used in) provided by financing activities	(957)	(134)	391
Change in cash and cash equivalents	5,083	1,899	(6,889)
Cash and cash equivalents at beginning of year	16,305	14,406	21,295
Cash and cash equivalents at end of year	21,388	16,305	14,406
Supplemental disclosures of cash flow information
Cash paid for interest	842	730	815
Cash paid for income taxes	247	0	0
Supplemental disclosures of non-cash investing and financing activities:
Adjustment of operating lease right-of-use assets and liabilities due to tenant allowance	29	0	0
Right-of-use assets obtained in exchange for lease liabilities	$ 0	$ 188	$ 0

Statements of Operations - USD ($) $ in Thousands	12 Months Ended
Statements of Operations - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Revenues:
Total net revenues	$ 31,642	$ 21,251	$ 21,832
Cost of Sales:
Total cost of sales	10,581	6,933	2,827
Gross profit	21,061	14,318	19,005
Operating expenses:
Research and development	3,322	3,996	6,235
General and administrative	18,931	18,582	14,265
Total operating expenses	22,253	22,578	20,500
Loss from operations	(1,192)	(8,260)	(1,495)
Other income (expense):
Interest and other income (expense), net	503	(761)	(1,006)
Gain on PPP loan forgiveness	0	0	365
Gain on equipment sale	0	0	181
Loss before income tax expense	(689)	(9,021)	(1,955)
Income tax expense	247	0	0
Net loss	$ (936)	$ (9,021)	$ (1,955)
Net loss per share, basic and diluted (in dollars per share)	$ (0.04)	$ (0.36)	$ (0.08)
Weighted average number of common shares outstanding, basic and diluted (in shares)	25,645,366	25,145,657	25,207,299
License [Member]
Revenues:
Total net revenues	$ 5,500	$ 10,000	$ 19,000
Cost of Sales:
Total cost of sales	1,000	1,640	1,500
Product Sales and Royalties [Member]
Revenues:
Total net revenues	26,142	11,251	2,832
Cost of Sales:
Total cost of sales	$ 9,581	$ 5,293	$ 1,327

Note 4 - Property and Equipment - Schedule of Property and Equipment (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Computer hardware and software	$ 187	$ 177
Furniture and fixtures	111	112
Equipment	52	52
Leasehold improvements	103	71
Construction in progress	0	12
Property, Plant and Equipment, Gross	453	424
Less: accumulated depreciation and amortization	(395)	(352)
Property and equipment, net	$ 58	$ 72

Insider Trading Arrangements	12 Months Ended
Insider Trading Arrangements	Dec. 31, 2023
Insider Trading Arr Line Items
Material Terms of Trading Arrangement [Text Block]	*Item 9B.* Other Information** Insider Trading Arrangements and Related Disclosure During the three months ended December 31, 2023, none of our directors or officers adopted or terminated a “Rule 10b5-1 trading arrangement” or “non-Rule 10b5-1 trading arrangement,” as each term is defined in Item 408(a) of Regulation S-K. We are committed to promoting high standards of ethical business conduct and compliance with applicable laws, rules and regulations. As part of this commitment, we have adopted our Insider Trading Policy governing the purchase, sale, and/or other dispositions of our securities by our directors, officers, employees and designated contractors. We believe our Insider Trading Policy is reasonably designed to promote compliance with insider trading laws, rules and regulations, and the exchange listing standards applicable to us. A copy of our Insider Trading Policy, including any amendments thereto, is filed as Exhibit 19.1 to this Annual Report on Form 10-K. *Item 9C.* Disclosure Regarding Foreign Jurisdictions that Prevent Inspections** Not applicable.
Rule 10b5-1 Arrangement Adopted [Flag]	false
Non-Rule 10b5-1 Arrangement Adopted [Flag]	false
Rule 10b5-1 Arrangement Terminated [Flag]	false
Non-Rule 10b5-1 Arrangement Terminated [Flag]	false

Note 4 - Property and Equipment

12 Months Ended

Dec. 31, 2023

Property, Plant and Equipment Disclosure [Text Block]

Note 4 – Property and Equipment

Property and equipment consist of the following:

	*December 31,*			*December 31,*
	*2023*			*2022*
Computer hardware and software	$	187		$	177
Furniture and fixtures		111			112
Equipment		52			52
Leasehold improvements		103			71
Construction in progress		—			12
		453			424
Less: accumulated depreciation and amortization		(395	)		(352	)
Property and equipment, net	$	58		$	72

Depreciation expense for the years ended December 31, 2023, 2022 and 2021 was $44, $66 and $155, respectively.

Note 13 - Employee Savings Plan

12 Months Ended

Dec. 31, 2023

Compensation and Employee Benefit Plans [Text Block]

Note 13 - Employee Savings Plan

The Company established an employee savings plan pursuant to Section 401(k) of the Internal Revenue Code, effective January 1, 2018. The plan allows participating employees to deposit into tax deferred investment accounts up to 100% of their salary, subject to annual limits. The Company makes certain matching contributions to the plan in amounts up to 4% of the participants’ annual cash compensation, subject to annual limits. For the years ended December 31, 2023, 2022 and 2021, the Company made $242, $172, and $154, respectively, in matching contributions.

Note 4 - Property and Equipment (Tables)

12 Months Ended

Dec. 31, 2023

Property, Plant and Equipment [Table Text Block]

	*December 31,*			*December 31,*
	*2023*			*2022*
Computer hardware and software	$	187		$	177
Furniture and fixtures		111			112
Equipment		52			52
Leasehold improvements		103			71
Construction in progress		—			12
		453			424
Less: accumulated depreciation and amortization		(395	)		(352	)
Property and equipment, net	$	58		$	72

Note 9 - Basic and Diluted Net Loss per Common Share (Details Textual) - shares	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount (in shares)	5,418,251	5,494,153	4,286,687

Note 10 - Related-party Transactions

12 Months Ended

Dec. 31, 2023

Note 10 — Related-Party Transactions

Harrow

The Chief Executive Officer of Harrow Health, Inc. (“Harrow”) was a member of the Company’s board of directors until March 17, 2021 when he retired from service with the board. The Company issued 25,000 shares to the Harrow CEO in April 2021 after his retirement from the Company’s board associated with RSUs that were previously fully vested. As of December 31, 2023, Harrow owned 1,982,000 shares of Eton’s common shares which represents approximately 7.7% of the Company’s common shares outstanding.

In March 2021, the Company closed its laboratory operation in Lake Zurich, Illinois and in May 2021 it reached an agreement for Imprimis Pharmaceuticals, a subsidiary of Harrow, to purchase its lab equipment for $700 which was $181 above the Company’s net book value of the equipment.

Chief Executive Officer

The CEO has a partial interest in a company that the Company has partnered with for its EM-100/Alaway Preservative Free eye allergy product as described below.

The Company acquired the exclusive rights to sell the EM-100 product in the United States pursuant to a sales and marketing agreement (the “Eyemax Agreement”) dated August 11, 2017 between the Company and Eyemax LLC (“Eyemax”), an entity affiliated with the Company’s CEO. Under the terms of the original agreement, the Company would pay Eyemax $250 upon FDA approval and $500 upon the first commercial sale of the product and pay Eyemax a royalty of 10% on the net sales of all products. The Eyemax Agreement was for an initial term of 10 years, subject to successive two-year renewals unless the Company elected to terminate the Eyemax Agreement.

On February 18, 2019, the Company entered into an Amended and Restated Agreement with Eyemax amending the Sales Agreement (the “Amended Agreement”). Pursuant to the Amended Agreement, Eyemax sold the Company all of its right, title and interest in EM-100, including any such product that incorporates or utilizes Eyemax’s intellectual property rights. Pursuant to the Amended Agreement, the Company paid Eyemax two milestone payments: (i) one milestone payment for $250 upon regulatory approval in the territory by the FDA of the first single agent product and (ii) one milestone payment for $500 following the first commercial sale of the first single agent product in the territory. The Company has realized $1,840 of the non-royalty and royalty revenue as of December 31, 2023. The EM-100 asset and its associated product rights were sold to Bausch Health on February 18, 2019 and future potential royalties of twelve percent on Bausch Health sales of the product, named Alaway® Preservative Free by Bausch, which was approved by the FDA in September 2020, will be split between Eyemax and the Company. There were no amounts due to Eyemax under the terms of the Amended Agreement as of December 31, 2023 or December 31, 2022, and Bausch Health discontinued sales of Alaway® Preservative Free effective March 24, 2023.

The entire disclosure for related party transactions. Examples of related party transactions include transactions between (a) a parent company and its subsidiary; (b) subsidiaries of a common parent; (c) and entity and its principal owners; and (d) affiliates.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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Note 14 - Commitments and Contingencies (Details Textual) - USD ($) $ / shares in Units, $ in Thousands					1 Months Ended				12 Months Ended
	Sep. 13, 2022	Oct. 28, 2021	Jun. 15, 2021	Mar. 26, 2020	Nov. 30, 2023	Oct. 31, 2023	Jul. 31, 2023	Jun. 30, 2022	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Mar. 14, 2023	Mar. 27, 2020	Jan. 23, 2019
Share Price (in dollars per share)									$ 2.32	$ 2.32	$ 5.64
Research and Development Expense, Total									$ 3,322	$ 3,996	$ 6,235
Cost of Goods and Services Sold									10,581	6,933	2,827
Common Stock [Member]
Share Price (in dollars per share)				$ 3.33
Indemnification Rights and Agreements [Member]
Other Commitment, Total									0	0
License [Member]
Cost of Goods and Services Sold									1,000	1,640	1,500
Carglumic Acid Tablets [Member]
Payments to Acquire Marketing Rights		$ 3,250
Commitment, Allocation of Profits, Percentage		50.00%
Betaine Anhydrous [Member]
Payments to Acquire Marketing Rights	$ 2,000				$ 125
Commitment, Allocation of Profits, Percentage	65.00%
Betaine Anhydrous [Member] \| Obligation Based on Commercial Success [Member]
Other Commitment, Total	$ 1,000
FDA-Approved ANDA For Nitisinone [Member]
Payments to Acquire Marketing Rights						$ 150
Commitment, Allocation of Profits, Percentage						80.00%
FDA-Approved ANDA For Nitisinone [Member] \| Obligation Based on Acceptance of FDA of NDA for product [Member]
Payments to Acquire Marketing Rights						$ 500
Azurity Pharmaceuticals, Inc. (“Azurity”) [Member]
Revenue, Additional Based on Event and Sales-based Milestones Achievements							$ 5,500
Azurity Pharmaceuticals, Inc. (“Azurity”) [Member] \| Milestone Method [Member]
Revenues									27,500
Tulex Pharmaceuticals, Inc. (“Tulex”) [Member] \| Obligation Based on Successful Manufacturing of Registration Batches [Member]
Other Commitment, Total												$ 450
Tulex Pharmaceuticals, Inc. (“Tulex”) [Member] \| Obligation Based on Acceptance of FDA of NDA for product [Member]
Other Commitment, Total												$ 200
Royalties, Percentage of Net Sales,												12.50%
Tulex Pharmaceuticals, Inc. (“Tulex”) [Member] \| Obligation Based on First Commercial Sale of Product [Member]
Other Commitment, Total												$ 250
Royalties, Percentage of Net Sales,												17.00%
Tulex Pharmaceuticals, Inc. (“Tulex”) [Member] \| Topiramate (fka ET-101) [Member]
Accounts Receivable, after Allowance for Credit Loss, Total											$ 5,000
Liqmeds Worldwide Limited (“LMW”) [Member] \| Licensing and Supply Agreement (the “Agreement”) [Member] \| Obligation Based on Issuance of Orange-book Listed Patent [Member]
Other Commitment, Total														$ 650
Diurnal Limited [Member] \| Exclusive Licensing and Supply Agreement (the “Alkindi License Agreement”) [Member]
Aggregate Value of Licensing Milestone Included in Research and Development Expense									$ 1,000
Diurnal Limited [Member] \| Exclusive Licensing and Supply Agreement (the “Alkindi License Agreement”) [Member] \| Common Stock [Member]
Stock Issued During Period, Shares, New Issues (in shares)				379,474
Stock Issued During Period, Value, New Issues				$ 1,264
Diurnal Limited [Member] \| Exclusive Licensing and Supply Agreement (the “Alkindi License Agreement”) [Member] \| Obligation Based on Exclusivity Status from FDA [Member]
Other Commitment, Total													$ 2,500
Diurnal Limited [Member] \| License [Member] \| Exclusive Licensing and Supply Agreement (the “Alkindi License Agreement”) [Member]
Commitment, Milestone Fee				$ 3,500
Crossject [Member] \| U.S. and Canadian rights to Crossject S.A.’s [Member]
Research and Development Expense, Total			$ 500
Royalty on Net Sales of Products, Percent			10.00%
Crossject [Member] \| U.S. and Canadian rights to Crossject S.A.’s [Member] \| Obligation Based on Development Milestones [Member]
Other Commitment, Total			$ 3,500
Crossject [Member] \| U.S. and Canadian rights to Crossject S.A.’s [Member] \| Obligation Based on Commercial Success [Member]
Other Commitment, Total			$ 6,000
Dr. Reddy’s [Member] \| License [Member]
Revenues								$ 5,000
Sintetica [Member]
Cost of Goods and Services Sold										$ 812

Note 5 - Debt (Details Textual)								1 Months Ended		12 Months Ended			33 Months Ended
Note 5 - Debt (Details Textual)	Apr. 05, 2022 USD ($)	May 20, 2021 USD ($)	Aug. 11, 2020 USD ($)	Jul. 21, 2020 USD ($)	May 04, 2020 USD ($)	Nov. 30, 2019 USD ($) $ / shares shares	Nov. 13, 2019 USD ($)	Aug. 31, 2020 USD ($) $ / shares shares	Nov. 30, 2019 USD ($) $ / shares shares	Dec. 31, 2023 USD ($) $ / shares	Dec. 31, 2022 USD ($) $ / shares	Dec. 31, 2021 USD ($)	Nov. 13, 2024	Sep. 30, 2023 $ / shares	Jun. 26, 2022 $ / shares shares	Nov. 13, 2020 USD ($)	Mar. 31, 2020 USD ($)
Long-Term Debt, Gross										$ 5,460,000
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares) \| shares															467,242
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) \| $ / shares															$ 3
Common Stock, Par or Stated Value Per Share (in dollars per share) \| $ / shares										$ 0.001	$ 0.001			$ 0.001
Long-Term Debt, Current Maturities										$ 5,380,000	$ 1,033,000
Interest Expense										1,060,000	955,000	$ 1,042,000
Amortization of Debt Discount (Premium)										117,000	127,000	148,000
Gain (Loss) on Extinguishment of Debt										0	0	365,000
SWK Warrants [Member]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares) \| shares						51,239		18,141	51,239
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) \| $ / shares						$ 5.86		$ 6.62	$ 5.86
Warrants and Rights Outstanding						$ 51,239			$ 51,239
Fair Value Adjustment of Warrants								$ 94,000	$ 226,000
Common Stock, Par or Stated Value Per Share (in dollars per share) \| $ / shares						$ 5.75		$ 6.85	$ 5.75
Warrants and Rights Outstanding, Term (Year)						7 years		7 years	7 years
SWK Warrants [Member] \| Measurement Input, Price Volatility [Member]
Warrants and Rights Outstanding, Measurement Input						95		95	95
SWK Warrants [Member] \| Measurement Input, Expected Dividend Rate [Member]
Warrants and Rights Outstanding, Measurement Input						0		0	0
SWK Warrants [Member] \| Measurement Input, Risk Free Interest Rate [Member]
Warrants and Rights Outstanding, Measurement Input						1.8		0.4	1.8
SWK Credit Agreement [Member] \| SWK Holdings Corporation [Member]
Debt Instrument, Face Amount							$ 10,000,000
Proceeds from Issuance of Debt						$ 5,000,000	5,000,000
Debt Instrument, Covenant Agreement, Additional Amount							$ 5,000,000
Debt Instrument, Covenant Requirements, Minimum Cash Balance																$ 3,000,000
SWK Credit Agreement [Member] \| SWK Holdings Corporation [Member] \| Scenario, Plan [Member]
Debt Instrument, Redemption Price, Percentage of Principal Amount Redeemed													5.50%
The Amended Agreement [Member]
Debt Instrument, Increase, Accrued Interest										$ 332,000	$ 231,000
The Amended Agreement [Member] \| SWK Holdings Corporation [Member]
Proceeds from Issuance of Debt			$ 2,000,000					$ 2,000,000
Debt Instrument, Covenant Agreement, Additional Amount																	$ 3,000,000
Long-Term Debt, Gross																	$ 2,000,000
Debt Instrument, Basis Spread on Variable Rate	8.00%
Debt Instrument, LIBOR Floor Rate	2.00%
Long-Term Debt, Current Maturities	$ 1,033,000
The Amended Agreement [Member] \| SWK Holdings Corporation [Member] \| Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]
Debt Instrument, Basis Spread on Variable Rate										8.26%
Debt Instrument SOFR Floor Rate										5.00%
Paycheck Protection Program Loan [Member]
Proceeds from Issuance of Debt					$ 361,000
Interest Expense		$ 4,000
Gain (Loss) on Extinguishment of Debt												$ 365,000
Economic Injury Disaster Loan Program [Member]
Proceeds from Issuance of Debt				$ 150,000
Interest Expense				$ 6,000

Note 12 - Income Taxes - Schedule of Reconciliation of Statutory Federal Tax Rate (Details)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Provision (benefit) at statutory rate	21.00%	21.00%	21.00%
Provision (benefit) at statutory rate	(21.00%)	(21.00%)	(21.00%)
Permanent items (primarily warrants and stock compensation)	39.10%	(3.30%)	(2.50%)
State tax benefit	6.50%	(8.70%)	(9.50%)
Federal rate change	0.00%	0.00%	0.00%
Other items	0.00%	0.00%	0.00%
Increase (decrease) in valuation allowance	(30.70%)	(33.00%)	(33.00%)
Increase (decrease) in valuation allowance	30.70%	33.00%	33.00%
Income tax expense	35.90%	0.00%	0.00%

Note 3 - Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2023

Schedule of Finite-Lived Intangible Assets, Future Amortization Expense [Table Text Block]

Year	*Amortization Expense*
2024	$	880
2025		880
2026		880
2027		756
2028		423
Thereafter		920
Total estimated amortization expense	$	4,739

Balance Sheets (Parentheticals) - $ / shares	Dec. 31, 2023	Dec. 31, 2022
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, authorized (in shares)	50,000,000	50,000,000
Common stock, issued (in shares)	25,688,062	25,353,119
Common stock, outstanding (in shares)	25,688,062	25,353,119

Document And Entity Information - USD ($)	12 Months Ended
Document And Entity Information - USD ($)	Dec. 31, 2023	Mar. 05, 2024	Jun. 30, 2023
Document Information [Line Items]
Entity Central Index Key	0001710340
Entity Registrant Name	Eton Pharmaceuticals, Inc.
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Document Fiscal Period Focus	FY
Document Fiscal Year Focus	2023
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2023
Document Transition Report	false
Entity File Number	001-38738
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	37-1858472
Entity Address, Address Line One	21925 W. Field Parkway, Suite 235
Entity Address, City or Town	Deer Park
Entity Address, State or Province	IL
Entity Address, Postal Zip Code	60010-7278
City Area Code	847
Local Phone Number	787-7361
Title of 12(b) Security	Common Stock, $0.001 par value
Trading Symbol	ETON
Security Exchange Name	NASDAQ
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	false
Document Financial Statement Error Correction [Flag]	false
Entity Shell Company	false
Entity Public Float			$ 84,700,000
Entity Common Stock, Shares Outstanding		25,688,062
Auditor Firm ID	170
Auditor Name	KMJ Corbin & Company LLP
Auditor Location	Irvine, California

Note 6 - Common Stock (Details Textual) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended	12 Months Ended
	Apr. 30, 2021	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Sep. 30, 2023	Jun. 26, 2022
Common Stock, Shares Authorized (in shares)		50,000,000	50,000,000		50,000,000
Common Stock, Par or Stated Value Per Share (in dollars per share)		$ 0.001	$ 0.001		$ 0.001
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Exercises in Period (in shares)		407,808
Share-Based Payment Arrangement, Shares Withheld for Tax Withholding Obligation (in shares)		50,867
Share-Based Payment Arrangement, Decrease for Tax Withholding Obligation		$ 180
Stock Issued During Period, Shares, Employee Stock Purchase Plans (in shares)	25,000	86,782	69,884
Stock Issued During Period, Shares, Restricted Stock Award, Net of Forfeitures (in shares)		91,402
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares)						467,242
Common Stock Warrants [Member]
Class of Warrant or Right, Exercised During Period (in shares)		0	1,067,242	135,650
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares)			632,231	94,808
The Two Thousand Eighteen Equity Incentive Plan Member
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Exercises in Period (in shares)		207,626	25,000
The Two Thousand Eighteen Equity Incentive Plan Member \| Cashless Stock Awards [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Exercises in Period (in shares)		407,808

Note 7 - Common Stock Warrants

12 Months Ended

Dec. 31, 2023

Stockholders' Equity Note, Warrants or Rights Warrants Disclosure [TextBlock]

Note 7 — Common Stock Warrants

Listed below is a summary of warrants outstanding as of December 31, 2023:

Description of Warrants	*No. of Shares*		*Exercise Price*
SWK Warrants – Debt (Tranche #1)		51,239	$	5.86
SWK Warrants – Debt (Tranche #2)		18,141	$	6.62
Total		69,380	6.05 (Avg)

The holders of these warrants or their permitted transferees, are entitled to rights with respect to the registration under the Securities Act of their shares that are converted to common stock, including demand registration rights and piggyback registration rights. These rights are provided under the terms of a registration rights agreement between the Company and the investors.

On June 26, 2022, 467,242 warrants from the 2017 preferred stock offering with an exercise price of $3.00 were set to expire. Prior to the expiration, the Company entered into an agreement with the warrant holders, whereby it modified the terms of the warrants to extend the expiration date until December 26, 2022 in exchange for the Company retaining the option of a cashless exercise provision. No other terms were modified. Due to this modification, the Company incurred a modification expense of $244 that is included in general and administration expense on the Statement of Operations for the year ended December 31, 2022.

A rollforward of the warrants outstanding is listed in the table below:

	*No. of Shares*
Balance as of the beginning of the year		483,380
Expiration of National Securities Corp – November 2018 issuance		(414,000	)
Balance as of the end of the year		69,380

There were 1,067,242 warrants exercised on a cashless basis in 2022 resulting in 632,231 shares of common stock being issued by the Company. There were 135,650 warrants exercised in 2021 (all on a cashless basis) resulting in 94,808 shares of common stock being issued by the Company. The intrinsic value of the warrants exercised was $2,367 in 2022 and $806 in 2021. There were no warrants exercised in 2023.

Note 12 - Income Taxes - Schedule of Provision for Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Federal	$ 61	$ 0	$ 0
State	186	0	0
Total current expense	247	0	0
Federal	(85)	2,272	460
State	(31)	812	185
Change in valuation allowance	116	(3,084)	(645)
Total deferred expense	0	0	0
Income tax expense	$ 247	$ 0	$ 0

Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

+ References + Details

Note 9 - Basic and Diluted Net Loss per Common Share (Tables)

12 Months Ended

Dec. 31, 2023

Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]

	*Year ended*			*Year ended*			*Year ended*
	*December 31,*			*December 31,*			*December 31,*
	*2023*			*2022*			*2021*

Net loss	$	(936	)	$	(9,021	)	$	(1,955	)
Weighted average common shares outstanding (basic and diluted)		25,645,366			25,145,657			25,207,299
Net loss per common share (basic and diluted)	$	(0.04	)	$	(0.36	)	$	(0.08	)

Note 1 - Company Overview

12 Months Ended

Dec. 31, 2023

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

Note 1 — Company Overview

Eton is an innovative pharmaceutical company focused on developing and commercializing treatments for rare diseases. The Company currently has four commercial rare disease products: ALKINDI SPRINKLE® for the treatment of adrenocortical insufficiency; Carglumic Acid for the treatment of hyperammonemia due to NAGS deficiency; Betaine Anhydrous for the treatment of homocystinuria; and Nitisinone for the treatment of hereditary tyrosinemia type 1 (HT-1). The Company has three additional product candidates in late-stage development: ET-400, ET-600, and ZENEO® hydrocortisone autoinjector.

Note 6 - Common Stock

12 Months Ended

Dec. 31, 2023

Equity [Text Block]

Note 6 — Common Stock

The Company has 50,000,000 authorized shares of $0.001 par value common stock under its Amended and Restated Certificate of Incorporation.

Note 6 — Common Stock (continued)

For the years ended December 31, 2023 and 2022, the Company issued 207,626 (net shares issued after a portion of 407,808 shares was a cashless exercise) and 25,000 shares, respectively, of its common stock resulting from stock option exercises under its 2018 Equity Incentive Plan (see Note 8). The Company withheld 50,867 shares for payroll tax obligations totaling $180 for the year ended December 31, 2023. For the years ended December 31, 2023 and 2022, the Company issued 86,782 and 69,884 shares, respectively, under the Company’s Employee Stock Purchase Plan (“ESPP”). For the year ended December 31, 2023, the Company issued 91,402 shares of its common stock due to the vesting of restricted stock units. In April 2021, the Company issued 25,000 shares of its common stock to a member of its board of directors upon his retirement from the board in connection with previously vested RSUs. During 2022, there were 1,067,242 warrants exercised, a portion of which was a cashless exercise, resulting in 632,231 shares of common stock being issued by the Company.

The entire disclosure for equity.

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Note 8 - Share-based Payment Awards (Tables)

12 Months Ended

Dec. 31, 2023

Share-Based Payment Arrangement, Option, Activity [Table Text Block]

						*Weighted Average*
				*Weighted Average*		*Remaining*
				*Exercise*		*Contractual*		*Aggregate Intrinsic*
	*Shares*			*Price*		*Term*		*Value*
Options outstanding as of January 1, 2023		4,402,292		$	4.71
Issued		1,108,291			3.51
Exercised		(407,808	)		2.23
Forfeited/Cancelled		(263,549	)		5.94
Options outstanding as of December 31, 2023		4,839,226		$	4.57		7.3	$	3,467
Options exercisable at December 31, 2023		3,399,896		$	4.78		6.7	$	2,432
Options vested and expected to vest at December 31, 2023		4,839,226		$	4.57		7.3	$	3,467

Schedule of Share-Based Payment Award, Stock Options, Valuation Assumptions [Table Text Block]

	*December 31, 2023*			*December 31, 2022*			*December 31, 2021*
Expected dividends		—	%		—	%		—	%
Expected volatility		70	%		70	%		70 - 80	%
Risk-free interest rate		3.5 - 4.7	%		1.5 - 3.9	%		0.9 - 1.4	%
Expected term (in years)		6.3			5.9			6.0
Weighted average grant date fair value	$	2.32		$	2.32		$	5.64

Share-Based Payment Arrangement, Restricted Stock and Restricted Stock Unit, Activity [Table Text Block]

				*Weighted Average Grant-Date*
	*Number of Units*			*Fair Value Per Unit*
Outstanding and unvested as of January 1, 2023		369,606		$	2.63
Granted		—			—
Vested		(91,402	)	$	2.63
Forfeited		(4,000	)	$	2.63
Outstanding and unvested as of December 31, 2023		274,204		$	2.63

Note 9 - Basic and Diluted Net Loss per Common Share - Schedule of Earnings (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Net income (loss)	$ (936)	$ (9,021)	$ (1,955)
Weighted average number of common shares outstanding, basic and diluted (in shares)	25,645,366	25,145,657	25,207,299
Net loss per share, basic and diluted (in dollars per share)	$ (0.04)	$ (0.36)	$ (0.08)

The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period.

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

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Note 11 - Leases (Tables)

12 Months Ended

Dec. 31, 2023

Lessee, Operating Lease, Disclosure [Table Text Block]

Assets	*Classification*
Operating lease right-of-use assets	Operating lease right-of-use assets, net	$	92
Total leased assets		$	92
Liabilities
Operating lease liabilities, current	Accrued liabilities	$	53
Operating lease liabilities, noncurrent	Operating lease liabilities, net of current portion		22
Total operating lease liabilities		$	75

Lessee, Operating Lease, Liability, to be Paid, Maturity [Table Text Block]

	*Total*			*2024*		*2025*		*2026*
Undiscounted lease payments	$	81		$	58	$	23	$	—
Less: Imputed interest		(6	)
Total lease liabilities	$	75

Note 14 - Commitments and Contingencies

12 Months Ended

Dec. 31, 2023

Commitments and Contingencies Disclosure [Text Block]

Note 14 — Commitments and Contingencies

Legal

The Company is subject to legal proceedings and claims that may arise in the ordinary course of business. The Company is not aware of any pending or threatened litigation matters at this time that may have a material impact on the operations of the Company.

License and Product Development Agreements

The Company has entered into various agreements in addition to those discussed above which are described below.

The three oral solution pediatric neurology product candidates discussed below, Topiramate, Zonisamide and Lamotrigine, were developed by the Company and its various product candidate development partners and the Company subsequently sold all its rights and interests in these three products to Azurity in 2021, but retained rights to certain royalties. The Company has recognized $27,500 in milestone revenues to date from these three products, and in June 2023 the Company amended its asset purchase agreement with Azurity and sold the remaining royalty interests it received back to Azurity for $5,500. Azurity will assume royalty or profit share obligations owed to development partners as well as additional milestone payments based on sales volume targets.

Prior to January 1, 2022, the Company worked with Tulex Pharmaceuticals, Inc. (“Tulex”) as a third-party contract manufacturer to develop an oral solution for Topiramate (fka ET-101) which targets a neurological condition. In November 2021, the product received approval from the FDA and was launched by Azurity in December 2021. The Company recognized a $5,000 milestone revenue at launch which was reflected in accounts receivable on the Company’s balance sheet at December 31, 2021 and subsequently collected in January 2022.

On January 23, 2019, the Company entered into a Licensing and Supply Agreement (the “Agreement”) with Liquimeds Worldwide (“LMW”) for Zonisamide oral liquid, a development stage product candidate (“ET-104”). Pursuant to the terms of the Agreement, the Company was to be responsible for regulatory and marketing activities and LMW was responsible for development and manufacturing of ET-104. The Company paid $650 to Azurity upon issuance of patent covering ET-104 listed in the FDA’s Orange Book in November 2022.

Note 14 — Commitments and Contingencies (continued)

In March 2020, the Company entered into an Exclusive Licensing and Supply Agreement (the “Alkindi License Agreement”) with Diurnal for marketing ALKINDI SPRINKLE® in the United States. In September 2020, ALKINDI SPRINKLE®’s New Drug Application (NDA) was approved by the FDA as a replacement therapy for pediatric patients with adrenocortical insufficiency.

For the initial licensing milestone fee, the Company paid Diurnal $3,500 in cash and issued 379,474 shares of its common stock to Diurnal which were valued at $1,264 based on the Company’s closing stock price of $3.33 on March 26, 2020. The Company paid Diurnal $1,000 for a 2023 sales milestone in January 2024 that was recorded as licensing cost of sales in December 2023, and will also pay Diurnal $2,500 if the product obtains orphan drug exclusivity status from the FDA.

In June 2021, the Company acquired U.S. and Canadian rights to Crossject’s ZENEO® hydrocortisone needleless autoinjector, which is under development as a rescue treatment for adrenal crisis. The Company paid Crossject $500 upon signing, $500 in March 2022 upon a completion of a successful technical batch and could pay up to $3,500 in additional development milestones and up to $6,000 in commercial milestones, as well as a 10% royalty on net sales.

In October 2021, the Company acquired the U.S. marketing rights to Carglumic Acid Tablets. The product’s Abbreviated New Drug Application (“ANDA”), which is owned by Novitium Pharma, was approved by the FDA in October 2021. The product is an AB-rated, substitutable generic version of Carbaglu®. The Company paid $3,250 upon signing and retains 50% of the product profits with the balance being distributed to the licensor and manufacturer. The Company launched this product in December 2021.

In June 2022, the Company sold its rights in Cysteine Hydrochloride, Biorphen®, and Rezipres® to Dr. Reddy’s. Under the terms of the transaction, Dr. Reddy’s assumed immediate ownership of Eton’s rights and interest in the products. The Company received $5,000 at closing, recorded as licensing revenue in the twelve months ended December 31, 2022. In accordance with the terms of the agreement, $812 of Sintetica profit share receivables were expensed as cost of goods sold in the twelve months ended December 31, 2022.

In September 2022, the Company acquired an FDA-approved ANDA for Betaine Anhydrous for oral solution. The ANDA was approved by the FDA in January 2022. The Company paid $2,000 upon signing and an additional $125 in November 2023, and could pay up to $1,000 in commercial milestones. The Company will retain 65% of the product profits with the balance being distributed to the licensor.

In March 2023, the Company acquired rare disease endocrinology product candidate ET-600 from Tulex. The Company paid $450 to Tulex in July 2023 as a result of successful manufacturing of registration batches. The Company will pay Tulex $200 upon acceptance by the FDA of the NDA for the product, $250 upon first commercial sale of the product, and tiered royalties of 12.5% to 17.0% on net sales.

In October 2023, the Company acquired an FDA-approved ANDA for Nitisinone. The ANDA was approved by the FDA in May 2023. The Company paid $150 to the seller and an additional $500 of cure amounts owed to the manufacturer upon signing. The Company will retain 80% of the product profits with the balance being distributed to the manufacturer.

Indemnification

As permitted under Delaware law and in accordance with the Company’s Amended and Restated Bylaws, the Company is required to indemnify its officers and directors for certain events or occurrences while the officer or director is or was serving in such capacity. The Company is also party to indemnification agreements with its directors and officers. The Company believes the fair value of the indemnification rights and agreements is minimal. Accordingly, the Company has not recorded any liabilities for these indemnification rights and agreements as of December 31, 2023 or 2022.

Note 10 - Related-party Transactions (Details Textual) - USD ($) $ in Thousands			1 Months Ended		9 Months Ended	12 Months Ended
	Feb. 18, 2019	Aug. 11, 2017	May 31, 2021	Apr. 30, 2021	Sep. 30, 2023	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Proceeds from Sale of Machinery and Equipment			$ 700			$ 0	$ 0	$ 700
Gain (Loss) on Disposition of Property Plant Equipment			$ 181			$ 0	0	$ 181
Related Party, Bausch Health [Member] \| Royalty [Member]
Related Party Transaction, Rate	12.00%
Harrow Health Inc [Member]
Common Stock, Shares Owned (in shares)						1,982,000
Harrow Health Inc [Member] \| Eton Pharmaceuticals [Member]
Equity Method Investment, Ownership Percentage						7.70%
The Eyemax Agreement [Member] \| Related Party, Eyemax LLC [Member]
Related Party Transaction, Terms (Year)		10 years
Related Party Transaction, Terms, Renewal (Year)		2 years
The Eyemax Agreement [Member] \| Related Party, Eyemax LLC [Member] \| Royalty [Member]
Related Party Transaction, Rate		10.00%
The Eyemax Agreement [Member] \| Related Party, Eyemax LLC [Member] \| Research and Development Expense [Member]
Related Party Transaction, Amounts of Transaction		$ 250
Covenant Based on Sale of First Commercial Product [Member] \| Related Party, Eyemax LLC [Member]
Related Party Transaction, Amounts of Transaction		$ 500
The Amended Agreement [Member] \| Related Party, Eyemax LLC [Member]
Related Party Transaction, Amounts of Transaction						$ 0	$ 0
Revenues					$ 1,840
The Amended Agreement [Member] \| Related Party, Eyemax LLC [Member] \| Covenant Based on Approval by The FDA [Member]
Related Party Transaction, Amounts of Transaction	$ 250
The Amended Agreement [Member] \| Related Party, Eyemax LLC [Member] \| Covenant Based on Sale of First Commercial Product [Member]
Related Party Transaction, Amounts of Transaction	$ 500
Chief Executive Officer [Member] \| Harrow Health Inc [Member] \| Restricted Stock Units (RSUs) [Member]
Stock Issued During Period, Shares, Issued for Services (in shares)				25,000

Note 11 - Leases - Schedule of Lease-related Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022	Nov. 30, 2022	Oct. 31, 2020
Operating Lease, Right-of-Use Asset	$ 92	$ 188	$ 188	$ 195
Liabilities
Operating lease liabilities, net of current portion	22	$ 107
Total operating lease liabilities	75		$ 188	$ 195
Noncurrent Assets [Member]
Operating Lease, Right-of-Use Asset	92
Accrued Liabilities [Member]
Liabilities
Operating lease liabilities, current	$ 53

Note 12 - Income Taxes (Tables)

12 Months Ended

Dec. 31, 2023

Schedule of Components of Income Tax Expense (Benefit) [Table Text Block]

	*Year ended*			*Year ended*			*Year ended*
	*December 31,*			*December 31,*			*December 31,*
	*2023*			*2022*			*2021*
Current:
Federal	$	61		$	—		$	—
State		186			—			—
Total current expense		247			—			—

Deferred:
Federal		(85	)		2,272			460
State		(31	)		812			185
Change in valuation allowance		116			(3,084	)		(645	)
Total deferred expense		—			—			—
Total provision	$	247		$	—		$	—

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

	*December 31,*			*December 31,*
	*2023*			*2022*
Net operating losses	$	15,447		$	17,183
Stock-based expenses		3,372			3,090
Accruals and other		2,697			1,359
Total deferred tax assets		21,516			21,632
Valuation allowance		(21,516	)		(21,632	)
Net deferred tax assets	$	—		$	—

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

	*Year ended*			*Year ended*			*Year ended*
	*December 31,*			*December 31,*			*December 31,*
	*2023*			*2022*			*2021*
Provision (benefit) at statutory rate		21.0	%		(21.0	)%		(21.0	)%
Permanent items (primarily warrants and stock compensation)		39.1			(3.3	)		(2.5	)
State tax benefit		6.5			(8.7	)		(9.5	)
Federal rate change		—			—			—
Other items		—			—			—
Increase (decrease) in valuation allowance		(30.7	)		33.0			33.0
Income tax expense		35.9	%		—	%		—	%

Note 7 - Common Stock Warrants - Summary of Rollforward of The Warrants Outstanding (Details)	12 Months Ended
	Dec. 31, 2023 shares
Balance (in shares)	69,380
Placement Agent Warrants, 2017 Preferred Stock Offering [Member]
Balance (in shares)	483,380
Class of Warrant or Right, Exercised During Period (in shares)	(414,000)
Balance (in shares)	69,380

Note 2 - Liquidity Considerations (Details Textual) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Retained Earnings (Accumulated Deficit)	$ (104,070)	$ (103,134)
Net Income (Loss) Attributable to Parent	(936)	(9,021)	$ (1,955)
Cash and Cash Equivalents, at Carrying Value	$ 21,388	$ 16,305

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