0001437749-25-009932 | 10-K | XBRL Viewer

Supplemental Balance Sheet Disclosures [Text Block]

4. Balance Sheet Components

Property and Equipment, net

Property and equipment, net consisted of the following (in thousands):

	*December 31,*
	*2024*			*2023*
Leasehold improvements	$	2,519		$	2,519
Laboratory equipment		1,342			1,247
Furniture, fixtures and equipment		966			966
Software		272			272
Construction in progress		29			—
		5,128			5,004
Less: Accumulated depreciation and amortization		(3,968	)		(3,476	)
	$	1,160		$	1,528

Depreciation expense for each of the years ended December 31, 2024 and 2023, was $0.5 million, respectively.

Intangible Assets, net

Intangible assets primarily consist of a license to utilize certain patents, know-how and technology relating to the Company’s NPS for biomedical applications acquired from Old Dominion University Research Foundation (ODURF), Eastern Virginia Medical School (EVMS), and the University of Southern California. In addition, the Company entered into a sponsored research agreement (“SRA”) with Old Dominion University’s Frank Reidy Research Center for Bioelectrics, a leading research organization in the field, which includes certain intellectual property rights arising from the research. The Company is amortizing the intangible assets over an estimated useful life of 12 years.

Intangible assets, net consisted of the following (in thousands):

	*December 31,*
	*2024*			*2023*
Acquired patents and licenses	$	7,985		$	7,985
Less: Accumulated amortization		(6,765	)		(6,099	)
	$	1,220		$	1,886

A schedule of the amortization of intangible assets is as follows (in thousands):

Years ending December 31:
2025	$	665
2026		555
	$	1,220

Accrued Expenses

Accrued expenses consisted of the following (in thousands):

	*December 31,*
	*2024*		*2023*
Compensation expense	$	4,097	$	3,199
Legal settlement		1,196		—
Severance		698		—
Professional fees		564		343
Clinical trial fees and costs		284		84
Other		188		188
	$	7,027	$	3,814

Note 13 - Subsequent Events

12 Months Ended

Dec. 31, 2024

Subsequent Events [Text Block]

13. Subsequent Events

2024 Rights Offering Warrants

Half of the warrants issued in the Company’s 2024 Rights Offering were redeemable for $0.01 per underlying share of common stock, on not less than thirty days’ written notice, if the VWAP of the Company’s common stock equaled or exceeded 150% of the exercise price for the warrants, or $16.50, for twenty consecutive trading days. In December 2024, the Company delivered an irrevocable notice of redemption to redeem the 2024 Rights Offering Warrants which were subject to this 150% redemption feature, because the VWAP of the Company’s common stock over the twenty consecutive trading days before the notice was $18.85. Pursuant to the 150% redemption feature, the Company redeemed 18,221 warrants on the redemption date, February 5, 2025, and at the date of this filing, there are no 2024 Rights Offering Warrants subject to the 150% redemption feature outstanding. Subsequent to December 31, 2024, but prior to the redemption date of February 5, 2025, the Company received approximately $2.6 million in gross proceeds from exercises of the 150% redemption feature 2024 Rights Offering Warrants.

The other half of the warrants issued in the 2024 Rights Offering remain redeemable by the Company for $0.01 per underlying share of common stock, on not less than thirty days’ written notice, if the VWAP of the Company’s common stock equals or exceeds 200% of the exercise price for the warrants, or $22.00, for twenty consecutive trading days. Although the 200% redemption feature of the 2024 Rights Offering Warrants has not yet been triggered, since December 31, 2024, the Company has received approximately $11.4 million in gross proceeds from exercises of warrants subject to the 200% redemption feature. If exercised, an additional $2.3 million of gross proceeds may be received if the remaining outstanding 2024 Rights Offering Warrants subject to the 200% redemption feature are exercised.

As of January 2, 2025, Robert W. Duggan, the Company’s majority stockholder and Co-Chairman, has exercised all of his outstanding 2024 Rights Offering Warrants. He has zero 150% redemption feature and zero 200% redemption feature warrants outstanding as of the date of this filing.

Executive Appointments

In January 2025, the Company appointed Paul A. LaViolette, the Company's Co-Chairman, as Chief Executive Officer and President of the Company. In connection with his appointment, the Company awarded Mr. LaViolette stock options to purchase up to 1,500,000 shares of the Company’s common stock, with an exercise price of $18.43 per share, the closing price of the Company’s common stock on January 8, 2025, the last trading day preceding Mr. LaViolette’s employment start date and date of grant. Subject to certain accelerated vesting provisions, 450,000 option shares will vest over four years, subject to a time-based vesting schedule, and 1,050,000 option shares will vest subject to both market and performance conditions related to achievement of certain market capitalization and revenue and gross margin targets. The options will vest and become exercisable once the specific targets are fulfilled.

In February 2025, the Company appointed Jon Skinner as Chief Financial Officer of the Company. In connection with his appointment, the Company awarded Mr. Skinner stock options to purchase up to 300,000 shares of the Company’s common stock, with an exercise price of $20.93 per share, the closing price of the Company’s common stock on January 31, 2025, the last trading day preceding Mr. Skinner’s employment start date and date of grant. Subject to certain accelerated vesting provisions, 150,000 option shares will vest over four years, subject to a time-based vesting schedule, and 150,000 option shares will vest subject to both market and performance conditions related to achievement of certain market capitalization and revenue targets. The options will vest and become exercisable once the specific targets are fulfilled.

Note 6 - Stockholders' Equity and Stock-based Compensation - Summary of Warrants Activity (Details)	12 Months Ended
	Dec. 31, 2024 $ / shares shares
Warrants outstanding, number of shares (in shares) \| shares	0
Warrants outstanding, weighted average exercise price (in dollars per share) \| $ / shares	$ 0
Warrants issued, number of shares (in shares) \| shares	5,999,999
Warrants issued, weighted average exercise price (in dollars per share) \| $ / shares	$ 11
Warrants exercised, number of shares (in shares) \| shares	(4,501,516)
Warrants exercised (in dollars per share) \| $ / shares	$ 11
Warrants Expired/Redeemed, number of shares (in shares) \| shares	0
Warrants Expired/Redeemed, weighted average exercise price (in dollars per share) \| $ / shares	$ 0
Warrants outstanding, number of shares (in shares) \| shares	1,498,483
Warrants outstanding, weighted average exercise price (in dollars per share) \| $ / shares	$ 11
Warrants outstanding, weighted average remaining contractual life (Year)	1 year 1 month 13 days

Note 11 - Restructuring Charges

12 Months Ended

Dec. 31, 2024

Restructuring and Related Activities Disclosure [Text Block]

11. Restructuring Charges

In February 2023, the Company eliminated seven positions and incurred a discrete restructuring related charge of $0.1 million which was fully recorded in February 2023 and the related expenses are included within total cost and expenses on the condensed consolidated statement of operations for the year ended December 31, 2023. This charge represents the total amount incurred in connection with the activity. The Company did not incur any restructuring related charges in the year ended December 31, 2024.

Note 5 - Goodwill (Details Textual) $ in Thousands	12 Months Ended
Note 5 - Goodwill (Details Textual) $ in Thousands	Dec. 31, 2024 USD ($)	Dec. 31, 2014 USD ($)	Dec. 31, 2023 USD ($)
Goodwill, Ending Balance	$ 2,791		$ 2,791
Goodwill, Impairment Loss	$ 0
Series of Individually Immaterial Business Acquisitions [Member]
Number of Businesses Acquired		3
Business Combination, Consideration Transferred, Total		$ 5,500
Goodwill, Ending Balance		$ 2,800

Amount, after accumulated impairment loss, of asset representing future economic benefit arising from other asset acquired in business combination or from joint venture formation or both, that is not individually identified and separately recognized.

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Note 3 - Fair Value of Financial Instruments - Financial Assets Measured on a Recurring Basis (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Total assets measured at fair value	$ 113,776	$ 41,184
Fair Value, Inputs, Level 1 [Member]
Total assets measured at fair value	113,776	41,184
Fair Value, Inputs, Level 2 [Member]
Total assets measured at fair value	0	0
Fair Value, Inputs, Level 3 [Member]
Total assets measured at fair value	0	0
Money Market Funds [Member]
Cash and Cash equivalents	113,776	41,184
Money Market Funds [Member] \| Fair Value, Inputs, Level 1 [Member]
Cash and Cash equivalents	113,776	41,184
Money Market Funds [Member] \| Fair Value, Inputs, Level 2 [Member]
Cash and Cash equivalents	0	0
Money Market Funds [Member] \| Fair Value, Inputs, Level 3 [Member]
Cash and Cash equivalents	$ 0	$ 0

Note 4 - Balance Sheet Components - Intangible Assets, Net (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Less: Accumulated amortization	$ (6,765)	$ (6,099)
Finite-Lived Intangible Assets, Net	1,220	1,886
Acquired Patents and Licenses [Member]
Acquired patents and licenses	$ 7,985	$ 7,985

Note 7 - Commitments and Contingencies (Tables)

12 Months Ended

Dec. 31, 2024

Schedule of Information Related to Right-of-use Assets and Lease Liabilities [Table Text Block]

	*Year Ended December 31,*
Assets:	*2024*		*2023*
Operating right-of-use assets	$	7,163	$	7,256

	*Year Ended December 31,*
Liabilities:	*2024*		*2023*
Lease liability, current	$	1,355	$	1,058
Lease liability, less current portion		7,543		8,086
Total lease liabilities	$	8,898	$	9,144

	*Year Ended December 31,*
	*2024*		*2023*
Cash paid for operating lease liabilities	$	1,938	$	1,845

Year ending December 31:
2025	$	2,151
2026		2,225
2027		2,302
2028		2,381
2029		2,080
Thereafter		73
Total lease payments		11,212
Less imputed interest		(2,314	)
Total lease liabilities	$	8,898

Weighted-average remaining lease term			4.88
Weighted-average discount rate			9.8	%

Note 4 - Balance Sheet Components - Property and Equipment, Net (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Property and equipment, gross	$ 5,128	$ 5,004
Less: Accumulated depreciation and amortization	(3,968)	(3,476)
Property and equipment, net	1,160	1,528
Leasehold Improvements [Member]
Property and equipment, gross	2,519	2,519
Laboratory Equipment [Member]
Property and equipment, gross	1,342	1,247
Furniture and Fixtures [Member]
Property and equipment, gross	966	966
Software and Software Development Costs [Member]
Property and equipment, gross	272	272
Construction in Progress [Member]
Property and equipment, gross	$ 29	$ 0

Note 7 - Commitments and Contingencies (Details Textual) $ / shares in Units, $ in Thousands		12 Months Ended
	Apr. 30, 2023 USD ($) $ / shares shares	Dec. 31, 2024 USD ($) $ / shares	Dec. 31, 2023 USD ($) $ / shares	Nov. 08, 2024 USD ($) ft²	Sep. 20, 2022 USD ($)	May 31, 2019 ft²	Jul. 31, 2017 ft²
Common Stock, Par or Stated Value Per Share (in dollars per share) \| $ / shares		$ 0.001	$ 0.001
Operating Lease, Right-of-Use Asset		$ 7,163	$ 7,256
Operating Lease, Liability		8,898	9,144
Corporate Headquarters in Hayward, California [Member]
Lessee, Operating Lease, Term of Contract (Year)							5 years
Area of Real Estate Property (Square Foot) \| ft²							15,700
Corporate Headquarters in Hayward, California [Member] \| Expansion Premises 1 [Member]
Area of Real Estate Property (Square Foot) \| ft²						13,300
Corporate Headquarters in Hayward, California [Member] \| Expansion Premises 2 [Member]
Area of Real Estate Property (Square Foot) \| ft²						21,300
Miami Lease [Member]
Lessee, Operating Lease, Term of Contract (Year)				65 months
Area of Real Estate Property (Square Foot) \| ft²				2,000
Lessee, Operating Lease, Renewal Term (Year)				5 years
Lessee, Operating Lease, Monthly Rent				$ 20
Lessee, Operating Lease, Rent, Annual Increase Percentage				3.00%
Lessee, Operating Lease, Discount Rate				8.00%
Operating Lease, Right-of-Use Asset				$ 800
Operating Lease, Expense		$ 2,500	2,300
Operating Lease, Liability				$ 800
Robert W. Duggan [Member] \| Private Placement [Member]
Stock Issued During Period, Shares, New Issues (in shares) \| shares	10,022,937
Common Stock, Par or Stated Value Per Share (in dollars per share) \| $ / shares	$ 0.001
Shares Issued, Price Per Share (in dollars per share) \| $ / shares	$ 6.51
Two Thousand Twenty Two Loan Agreement [Member] \| Robert W. Duggan [Member]
Debt Instrument, Face Amount					$ 65,000
Debt Instrument Quarterly Interest Rate					5
Debt Instrument, Increase, Accrued Interest			1,700
Interest Expense			$ 1,100
Loan Agreement [Member]
Debt Instrument, Decrease, Forgiveness	$ 65,000
Interest Payable	$ 200

Note 8 - Income Taxes - Deferred Tax Asset (Liability) (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Accruals	$ 1,218	$ 1,502
Net operating loss carryforwards	66,952	61,072
Tax credit carryforwards	10,838	9,815
Stock-based compensation	9,588	7,704
R&D capitalization	10,358	7,384
Lease liability	1,869	1,920
Property and equipment	35	7
Intangible assets	279	99
Gross deferred tax assets	101,137	89,503
Valuation allowance	(99,542)	(87,853)
Total deferred tax assets	1,595	1,650
Right-of-use assets	(1,595)	(1,650)
Total deferred tax liabilities	(1,595)	(1,650)
Net deferred tax assets/(liabilities)	$ 0	$ 0

Note 9 - Segment Reporting (Tables)

12 Months Ended

Dec. 31, 2024

Schedule of Segment Reporting Information, by Segment [Table Text Block]

	*Year Ended December 31,*
	*2024*			*2023*
Total revenues	$	—		$	—
Cross platform research and engineering¹		13,487			15,742
Manufacturing²		4,939			2,278
Clinical and regulatory³		4,052			2,737
Adjusted general and administrative⁴		15,909			13,317
Sales and marketing⁵		3,106			1,113
Other segment items⁶		14,764			8,387
Total other income, net		(2,672	)		(1,364	)
Net loss	$	(53,585	)	$	(42,210	)

Note 3 - Fair Value of Financial Instruments (Tables)

12 Months Ended

Dec. 31, 2024

Fair Value, Assets Measured on Recurring Basis [Table Text Block]

		*December 31, 2024*
Assets	*Classification*	*Level 1*		*Level 2*		*Level 3*		*Total*
Money market funds	Cash and cash equivalents	$	113,776	$	—	$	—	$	113,776
Total assets measured at fair value		$	113,776	$	—	$	—	$	113,776

		*December 31, 2023*
Assets	*Classification*	*Level 1*		*Level 2*		*Level 3*		*Total*
Money market funds	Cash and cash equivalents	$	41,184	$	—	$	—	$	41,184
Total assets measured at fair value		$	41,184	$	—	$	—	$	41,184

Consolidated Balance Sheets (Parentheticals) - $ / shares	Dec. 31, 2024	Dec. 31, 2023
Preferred stock, par value (in dollars per share)	$ 0.001	$ 0.001
Preferred stock, shares authorized (in shares)	50,000,000	50,000,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	500,000,000	500,000,000
Common stock, shares issued (in shares)	65,926,000	55,144,000
Common stock, shares outstanding (in shares)	65,926,000	55,144,000

Note 6 - Stockholders' Equity and Stock-based Compensation

12 Months Ended

Dec. 31, 2024

Share-Based Payment Arrangement [Text Block]

6. Stockholders’ Equity and Stock-Based Compensation

Preferred Stock

The Company has authorized a total of 50,000,000 shares of preferred stock, par value $0.001 per share, none of which were outstanding at December 31, 2024 and 2023. The Company’s Board of Directors (the “Board”) has the authority to issue preferred stock and to determine the rights, preferences, privileges, and restrictions, including voting rights, without any further vote or action by the Company’s stockholders.

Common Stock

The Company has authorized a total of 500,000,000 shares of common stock, par value $0.001 per share.

2024 Rights Offering and Subscription Rights

On March 28, 2024, the Company announced that its Board unanimously approved plans to initiate a rights offering, whereby the Company would distribute non-transferable subscription rights at no charge to all holders of the Company's common stock, par value $0.001 per share (the "Common Stock"), as of the close of business on a record date to be determined. On May 20, 2024, the Company announced that the Board had set May 31, 2024 as the record date (the "Record Date"). All holders of Common Stock as of the Record Date received non-transferable subscription rights to purchase up to an aggregate of six million units (the "2024 Units") with an aggregate offering value of up to $60 million (the "2024 Rights Offering") at a price per 2024 Unit equal to the lesser of: (i) $10 (the "Initial Price") and (ii) the volume weighted average price of the Common Stock for the ten trading day period through and including the expiration date, June 26, 2024 (the "Expiration Date"), of the Rights Offering (the "Alternate Price"). Each subscription right entitled the holder to purchase 0.10864186 2024 Units for each share of Common Stock owned as of the Record Date. Each 2024 Unit consisted of one share of Common Stock and two warrants, each being a warrant to purchase one-half of one share of Common Stock. The subscription rights were to expire and have no value if they were not exercised prior to the Expiration Date. The Company determined that the equity-classified subscription rights represent a pro-rata distribution issued to existing stockholders as of the Record Date, which is based on a purchase price of $10 per 2024 Unit as compared to (1) the price of $11.55 per one share of Common Stock on the Record Date, plus (2) the value of the warrants on the Record Date. The Company determined the fair value of the equity-classified subscription rights as of the Record Date, which involved the use of a Monte Carlo simulation model to value the underlying warrants. The Monte Carlo simulation model was based on certain significant unobservable inputs, such as a risk-free interest rate, stock price volatility, dividend yield, and expected term of the rights offering. The fair value of the equity-classified subscription rights was $47.7 million and was recorded in equity on the balance sheet as part of additional paid-in capital. The deemed pro-rata distribution to shareholders of $47.7 million was reflected as an offsetting reduction in additional paid-in capital. The Company is in an accumulated deficit position and has elected a policy of recognizing the deemed pro-rata distribution to shareholders as a reduction to additional paid-in capital rather than a further increase to its accumulated deficit.

On July 3, 2024, the Company announced the closing of its 2024 Rights Offering. The 2024 Rights Offering resulted in the sale of six million 2024 Units, at a price of $10.00 per 2024 Unit. Each 2024 Unit consisted of one share of the Company’s common stock, par value $0.001 per share, and two warrants, each being a warrant to purchase one-half of one share of common stock. The common stock and warrants comprising the 2024 Units separated upon the closing of the 2024 Rights Offering and were issued individually. A total of 5,999,998 shares of common stock and warrants to acquire up to approximately an additional six million shares of common stock were issued in the offering. The Company received aggregate gross proceeds from the 2024 Rights Offering of $60 million. See 2024 Rights Offering Warrants below for additional details of the warrants. Robert W. Duggan, the Company’s majority stockholder and Co-Chairman, purchased approximately 88% of the units offered through the 2024 Rights Offering.

Private Placement Securities Purchase Agreement

On April 30, 2023, the Company entered into a Securities Purchase Agreement with Robert W. Duggan, the Company’s majority stockholder and Co-Chairman, pursuant to which the Company agreed to issue and sell to Mr. Duggan 10,022,937 shares of the Company’s common stock, par value $0.001 per share, in a Private Placement, at a price per share of $6.51. The parties completed the Private Placement on May 9, 2023, after satisfying all pre-closing conditions, and the Company issued the full number of shares to Mr. Duggan. The shares were paid for through the cancellation of the principal sum of $65.0 million borrowed by the Company pursuant to the 2022 Loan Agreement (See Note 7), together with all accrued and unpaid interest outstanding owed at the time of closing.

2022 Rights Offering

On June 9, 2022, the Company completed a rights offering (the "2022 Rights Offering") resulting in the sale of 7,317,072 units (the "Units"), at a price of $2.05 per Unit, with each Unit consisting of one share of the Company’s common stock, par value $0.001 per share, and one warrant (the "2022 Rights Offering Warrants") to purchase one share of common stock at a price of $2.05 per share. The common stock and warrants comprising the Units separated upon the closing of the 2022 Rights Offering and were issued individually. 7,317,072 shares of common stock and warrants to acquire up to an additional 7,317,072 shares of common stock were issued in the 2022 Rights Offering. The Company received aggregate gross proceeds from the 2022 Rights Offering of $15 million. In May 2023, the Company delivered an irrevocable notice of redemption to warrant holders and, on June 16, 2023, it redeemed the last of the outstanding 2022 Rights Offering Warrants at a price of $0.01 per warrant share. See the 2022 Rights Offering Warrants section below for further details. Robert W. Duggan, the Company’s majority stockholder and Co-Chairman, purchased approximately 56% of the shares offered through the 2022 Rights Offering.

Common Stock Warrants

2024 Rights Offering Warrants

In connection with the 2024 Rights Offering, the Company issued 2024 Rights Offering Warrants to purchase a total of 5,999,999 shares of its common stock at an exercise price of $11.00 per whole share, which equaled 110% of the subscription price for the Units. The aggregate number of shares of our common stock issuable upon the exercise of each set of warrants included in a given subscription for Units was rounded up to the nearest whole share. Warrants are exercisable immediately and will expire on the fifth anniversary of the closing of the 2024 Rights Offering. Half of the warrants issued in the rights offering were redeemable for $0.01 per underlying share of common stock, on not less than thirty days’ written notice, if the VWAP of the Company’s common stock equaled or exceeded 150% of the exercise price for the warrants, or $16.50, for twenty consecutive trading days. In December 2024, the Company delivered an irrevocable notice of redemption to redeem this first tranche of common stock warrants because the VWAP of the Company's common stock over the twenty consecutive trading days before the notice was $18.85. Accordingly, pursuant to the 150% redemption feature, we redeemed 18,221 warrants on the redemption date, February 5, 2025, and none of these warrants are still outstanding. The other half of the warrants issued in the rights offering remain redeemable for $0.01 per underlying share of common stock, on not less than thirty days’ written notice, but only if the VWAP of the Company’s common stock equals or exceeds 200% of the exercise price for the warrants, or $22.00, for twenty consecutive trading days. As of December 31, 2024, there were 253,246 2024 Rights Offering Warrants outstanding which were subject to the 150% redemption feature and there were 1,245,237 2024 Rights Offering Warrants outstanding which were subject to the 200% redemption feature. As of December 31, 2024, we have received $49.4 million in gross proceeds from exercises of the 2024 Rights Offering Warrants. Refer to Note 13 for disclosure of gross proceeds received subsequent to December 31, 2024.

2022 Rights Offering Warrants

In connection with the 2022 Rights Offering, the Company issued 2022 Rights Offering Warrants to purchase a total of 7,317,072 shares of its common stock at an exercise price of $2.05. The 2022 Rights Offering Warrants were subject to redemption by the Company for $0.01 per underlying share of common stock, on not less than 30 days written notice, if the volume weighted average price of the Company’s common stock equals or exceeds 200% of the exercise price for the warrants, subject to adjustment, per share, for 20 consecutive trading days, provided that the Company may not redeem the warrants prior to the date that is three months after the issuance date. On May 10, 2023, the Company issued a press release announcing that on May 9, 2023 the terms for warrant redemption had been met. Pursuant to the redemption, the Company redeemed 66,175 warrants on the redemption date, June 16, 2023. Prior to the redemption date, warrants to purchase 7,250,897 shares were exercised, generating approximately $14.9 million of total gross proceeds to the Company. As of December 31, 2024, there were no 2022 Rights Offering Warrants outstanding.

A summary of total warrants activity for the year ended December 31, 2024 is presented below:

						*Weighted*
						*Average*
				*Weighted*		*Remaining*
	*Number of*			*Average*		*Contractual*
	*Shares*			*Exercise Price*		*Life (in Years)*
Warrants outstanding at December 31, 2023		—		$	—		—
Issued		5,999,999			11.00
Exercised		(4,501,516	)		11.00
Expired/Redeemed		—			—
Warrants outstanding at December 31, 2024		1,498,483		$	11.00		1.12

Equity Plans

2017 Equity Incentive Plan and 2017 Inducement Equity Incentive Plan

The Board of Directors of the Company (the "Board") previously adopted, and the Company’s stockholders approved, the Company’s 2017 Equity Incentive Plan (the "2017 Plan").

The 2017 Plan has a 10-year term, and provides for the grant of stock options, stock appreciation rights, restricted stock, RSUs, performance units, and performance shares to employees, directors and consultants of the Company and any parent or subsidiary of the Company, as the Compensation Committee of the Board may determine. Subject to an annual evergreen increase and adjustment in the case of certain capitalization events, the Company initially reserved 1,500,000 shares of the Company’s common stock for issuance pursuant to awards under the 2017 Plan. In addition, shares remaining available under the Company’s 2015 Equity Incentive Plan, as amended (the “2015 Plan”), and shares reserved but not issued pursuant to outstanding equity awards that expire or terminate without being exercised or that are forfeited or repurchased by the Company will be added to the shares of common stock available for issuance under the 2017 Plan. The 2017 Plan is administered by the Board’s Compensation Committee. Effective at both January 1, 2024 and 2023, the number of shares of common stock available under the 2017 Plan increased by 1,200,000, respectively, pursuant to the evergreen provision of the 2017 Plan. Under the evergreen provision of the 2017 Plan, the share increase is determined based on the least of (i) 1,200,000 shares, (ii) 4% of the Company’s common stock outstanding at December 31 of the immediately preceding year, or (iii) such number of shares as determined by the Board. Additionally, in December 2023, the number of shares of common stock available under the 2017 Plan increased by 1,375,000 shares as a result of a stockholder vote held at a special meeting of stockholders. As of December 31, 2024, 77,490 shares of common stock remained available for issuance under the 2017 Plan.

During November 2017, the Board of the Company adopted the 2017 Inducement Equity Incentive Plan (the “Inducement Plan”) and reserved 1,000,000 shares of the Company’s common stock for issuance pursuant to equity awards granted under the Inducement Plan. The Inducement Plan was adopted without stockholder approval.

The Inducement Plan has a 10-year term and provides for the grant of equity-based awards, including non-statutory stock options, RSUs, restricted stock, stock appreciation rights, performance shares and performance units, and its terms are substantially similar to the 2017 Plan, including with respect to treatment of equity awards in the event of a “merger” or “change in control” as defined under the Inducement Plan. Options issued under the Inducement Plan may have a term up to ten years and have variable vesting provisions. New hire grants generally vest 25% per year starting upon the first anniversary of the grant. Equity-based awards issued under the Inducement Plan are only issuable to individuals not previously engaged as employees or non-employee directors of the Company prior to the Inducement Plan’s adoption date. In May 2021, the Board approved an amendment to the Inducement Plan to reserve an additional 1,000,000 shares of the Company’s common stock for issuance pursuant to the Inducement Plan. And, in March 2024, the Board approved a second amendment to the Inducement Plan to reserve an additional 2,000,000 shares of the Company’s common stock for issuance pursuant to the Inducement Plan. As of December 31, 2024, 2,941,626 shares of common stock were available for issuance under the Inducement Plan.

A summary of stock option activity under the 2015 Plan, 2017 Plan and Inducement Plan for the year ended December 31, 2024 is presented below:

	*Stock Options Outstanding*
	*Number of shares*			*Weighted average exercise price*		*Weighted average remaining life (in years)*
Balances — December 31, 2023		9,466,036		$	9.01		7.78
Options granted		3,018,643			10.38
Options exercised		(160,847	)		5.41
Options canceled		(1,308,542	)		7.51
Options expired		(35,958	)		19.82
Balances — December 31, 2024		10,979,332		$	9.59		7.11
Exercisable — December 31, 2024		4,525,945		$	12.74		4.98

Time-based Options

The Company awards time-based options which vest and become exercisable, subject to the individual’s continued employment or service through the applicable vesting date. Time-based options can have various vesting schedules, most commonly new hire grants which generally vest 25% per year starting upon the first anniversary of the grant.

A summary of the time-based stock option activity under the 2015 Plan, 2017 Plan and Inducement Plan for the year ended December 31, 2024 is presented below:

	*Stock Options Outstanding*
	*Number of shares*			*Weighted average exercise price*		*Weighted average remaining life (in years)*
Balances — December 31, 2023		6,141,906		$	10.48		7.07
Options granted		2,124,643			11.31
Options exercised		(150,897	)		5.57
Options canceled		(605,542	)		7.59
Options expired		(34,958	)		20.30
Options modified from performance-based to time-based		600,113			4.18
Balances — December 31, 2024		8,075,265		$	10.49		6.72
Exercisable — December 31, 2024		4,093,267		$	13.27		4.80

The intrinsic value of time-based options exercised during the years ended December 31, 2024 and 2023 was $1.9 million and $0.9 million, respectively.

The fair value of the time-based options granted to employees and directors during the years ended December 31, 2024 and 2023 was $18.7 million and $9.0 million, respectively.

Time-based Modifications

In October 2024, the Board approved changes to the performance-based vesting conditions of certain unvested outstanding common stock option awards that were improbable of vesting. Specifically, 600,113 performance-based stock option awards were modified to time-based vesting criteria. The modified time-based awards will vest and become exercisable, subject to the individual’s continued employment or service through the applicable vesting date, based upon individually specific vesting schedules with annual vesting milestones. The vesting schedules have a range from two to four years. The fair value of the time-based modification awards at the modification date was $8.8 million. As a result of this modification, the Company recognized an additional $2.9 million of stock-based compensation expense during the year ended December 31, 2024.

Performance Options

Certain stock options awarded to the Company’s executives and other employees contain performance conditions related to certain financial measures and achievements of strategic and operational milestones. The options will vest and become exercisable once the specific performance condition is fulfilled. In October 2024, the Board approved changes to the performance-based vesting conditions of certain unvested outstanding common stock option awards that were improbable of vesting. Specifically, certain performance-based stock option awards were changed to time-based vesting criteria and certain performance-based stock option awards were changed to market-based vesting criteria.

A summary of the performance option activity under the 2017 Plan and Inducement Plan for the year ended December 31, 2024 is presented below:

	*Stock Options Outstanding*
	*Number of shares*			*Weighted average exercise price*		*Weighted average remaining life (in years)*
Balances — December 31, 2023		1,224,130		$	5.51		8.53
Options granted		39,000			8.44
Options exercised		(9,950	)		2.92
Options canceled		(3,000	)		2.92
Options expired		(1,000	)		2.92
Options modified from performance-based to time-based and market-based		(806,502	)		4.49
Balances — December 31, 2024		442,678		$	7.71		6.79
Exercisable — December 31, 2024		432,678		$	7.69		6.73

The fair value of the performance options granted to employees during the years ended December 31, 2024 and 2023 was $0.3 million and $2.0 million, respectively.

The Company estimates the fair value of time-based and performance-based stock options on the grant date and modification date using the Black-Scholes option pricing model. The estimated fair value of these employee stock options is amortized on a straight-line basis over the requisite service period of the awards. The Company reviews, and when deemed appropriate, updates the assumptions used on a periodic basis. The fair value of time-based and performance-based stock options was estimated using the following weighted-average assumptions:

	*Year Ended December 31,*
	*2024*		*2023*
Expected term in years		2.9 - 6.3		5.0 - 8.0
Expected volatility		91% - 99%		89% - 95%
Risk-free interest rate		3.8% - 4.5%		3.7% - 4.4%
Dividend yield		—		—

Market-based Options

Certain stock options awarded by the Company contain market conditions related to achievement of certain market capitalization targets. The options will vest and become exercisable once the specific market capitalization target is fulfilled.

A summary of the market-based option activity under the 2017 Plan for the year ended December 31, 2024 is presented below:

	*Stock Options Outstanding*
	*Number of shares*			*Weighted average exercise price*		*Weighted average remaining life (in years)*
Balances — December 31, 2023		2,100,000		$	6.78		9.44
Options granted		855,000			8.16
Options exercised		—			—
Options canceled		(700,000	)		7.45
Options expired		—			—
Options modified from performance-based to market-based		206,389			5.39
Balances — December 31, 2024		2,461,389		$	6.95		8.43
Exercisable — December 31, 2024		—			—		—

The fair value of the market-based options granted to employees during the years ended December 31, 2024 and 2023 was $5.3 million and $10.5 million, respectively.

Market-based Modifications

In October 2024, the Board approved changes to the performance-based vesting conditions of certain unvested outstanding common stock option awards that were improbable of vesting. Specifically, 206,389 performance-based stock option awards were modified to market-based vesting criteria. The modified market-based awards will vest and become exercisable, subject to the individual’s continued employment and service through the applicable vesting date, based upon the achievement of certain market capitalization targets. The fair value of these market-based modification awards at the modification date was $2.8 million. Additionally, in October 2024, the Board approved a modification to certain market-based awards to adopt a uniform methodology for calculating its market capitalization whereas they aligned all awards to use consecutive calendar days and not consecutive trading days in the calculation. As a result of this modification, incremental value of $0.4 million will be recognized over the remaining derived service period.

The Company estimates the fair value of market-based stock options on the grant date and modification date using a Monte Carlo simulation model. The estimated fair value of these employee stock options is amortized over the requisite service period for each tranche of the awards. The requisite service period is the service period derived from the Monte Carlo simulation model. If the market capitalization targets are met sooner than the derived service period, the Company will accelerate the recognition of stock-based compensation expense to reflect the cumulative expense associated with the vested shares. The fair value of market-based stock options was estimated using the following weighted-average assumptions:

	*Year Ended December 31,*
	*2024*		*2023*
Expected term in years		1.4 - 4.3		4.0 - 6.3
Expected volatility		90%		90%
Risk-free interest rate		3.5% - 3.7%		3.4% - 3.8%
Dividend yield		—		—

2017 Employee Stock Purchase Plan

The Board previously adopted and the stockholders approved the Company’s 2017 Employee Stock Purchase Plan (the "2017 ESPP").

The 2017 ESPP is a broad-based plan that provides employees of the Company and its designated affiliates with the opportunity to become stockholders through periodic payroll deductions that are applied towards the purchase of Company common shares at a discount from the then-current market price. Subject to adjustment in the case of certain capitalization events, a total of 250,000 common shares of the Company were available for purchase at adoption of the 2017 ESPP. Pursuant to the 2017 ESPP, the annual share increase pursuant to the evergreen provision is determined based on the least of (i) 450,000 shares, (ii) 1.5% of the Company’s common stock outstanding at December 31 of the immediately preceding year, or (iii) such number of shares as determined by the Board. In 2024, the Company reserved an additional 450,000 shares under the 2017 ESPP pursuant to the evergreen provision. In 2023, the Board waived the evergreen provision and no additional shares were reserved under the 2017 ESPP. During the years ended December 31, 2024 and 2023, the Company issued 117,539 and 347,681 shares of common stock under the 2017 ESPP, respectively. As of December 31, 2024, 445,779 shares of common stock remained available for issuance under the 2017 ESPP.

The Company estimates the fair value of ESPP grants on their grant date using the Black-Scholes option pricing model. The estimated fair value of ESPP grants is amortized on a straight-line basis over the requisite service period of the grants. The Company reviews, and when deemed appropriate, updates the assumptions used on a periodic basis. The Company utilizes its estimated volatility in the Black-Scholes option pricing model to determine the fair value of ESPP grants. The fair value of ESPP grants was estimated using the following weighted-average assumptions:

	*Year Ended December 31,*
	*2024*		*2023*
Expected term in years		0.5 - 1.0		0.5 - 1.0
Expected volatility		98%		83%
Risk-free interest rate		4.4% - 5.3%		5.1% - 5.5%
Dividend yield		—		—

Stock-based Compensation

Total stock-based compensation expense recorded in the consolidated statements of operations and comprehensive loss was as follows (in thousands):

	*Year Ended December 31,*
	*2024*		*2023*
Research and development		6,293		3,491
General and administrative		7,293		3,690
Total stock-based compensation expense	$	13,586	$	7,181

As of December 31, 2024, not all of the performance conditions of the performance options are probable to be achieved. Compensation expense has only been recognized for those conditions that are assumed to be probable.

Total stock-based compensation expense by award type was as follows (in thousands):

	*Year Ended December 31,*
	*2024*		*2023*
Time-based options	$	10,343	$	3,827
Performance-based options		38		1,977
Market-based options		2,926		1,130
ESPP		279		247
Total stock-based compensation expense	$	13,586	$	7,181

Total time-based stock-based compensation expense for the year ended December 31, 2024, includes $2.9 million of additional expense due to the modification of certain performance-based stock option awards to time-based stock option awards, and $0.7 million of additional expense, net of forfeiture of unvested options that were previously expensed for $0.6 million, due to the modification of a certain award whereby there was a partial acceleration of vesting upon the departure of the Company's former Chief Executive Officer.

At December 31, 2024, there was $34.8 million of unrecognized compensation cost related to unvested stock-based compensation arrangements, which is expected to be recognized over a weighted average period of 2.85 years.

Note 4 - Balance Sheet Components (Tables)

12 Months Ended

Dec. 31, 2024

Property, Plant and Equipment [Table Text Block]

	*December 31,*
	*2024*			*2023*
Leasehold improvements	$	2,519		$	2,519
Laboratory equipment		1,342			1,247
Furniture, fixtures and equipment		966			966
Software		272			272
Construction in progress		29			—
		5,128			5,004
Less: Accumulated depreciation and amortization		(3,968	)		(3,476	)
	$	1,160		$	1,528

Schedule of Finite-Lived Intangible Assets [Table Text Block]

	*December 31,*
	*2024*			*2023*
Acquired patents and licenses	$	7,985		$	7,985
Less: Accumulated amortization		(6,765	)		(6,099	)
	$	1,220		$	1,886

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

Years ending December 31:
2025	$	665
2026		555
	$	1,220

Schedule of Accrued Liabilities [Table Text Block]

	*December 31,*
	*2024*		*2023*
Compensation expense	$	4,097	$	3,199
Legal settlement		1,196		—
Severance		698		—
Professional fees		564		343
Clinical trial fees and costs		284		84
Other		188		188
	$	7,027	$	3,814

Note 6 - Stockholders' Equity and Stock-based Compensation - Summary of Market-based Option Activity (Details) - Market-based Options [Member]	12 Months Ended
	Dec. 31, 2024 $ / shares shares
Options balances, number of shares (in shares) \| shares	2,100,000
Options balances, weighted average exercise price (in dollars per share) \| $ / shares	$ 6.78
Options granted, number of shares (in shares) \| shares	855,000
Options granted, weighted average exercise price (in dollars per share) \| $ / shares	$ 8.16
Options exercised, number of shares (in shares) \| shares	0
Options exercised, weighted average exercise price (in dollars per share) \| $ / shares	$ 0
Options canceled, number of shares (in shares) \| shares	(700,000)
Options canceled, weighted average exercise price (in dollars per share) \| $ / shares	$ 7.45
Options expired, number of shares (in shares) \| shares	0
Options expired, weighted average exercise price (in dollars per share) \| $ / shares	$ 0
Options modified, number of shares (in shares) \| shares	206,389
Options modified, weighted average exercise price (in dollars per share) \| $ / shares	$ 5.39
Options balances, number of shares (in shares) \| shares	2,461,389
Options balances, weighted average exercise price (in dollars per share) \| $ / shares	$ 6.95
Options balances, weighted average remaining life (Year)	8 years 5 months 4 days
Options exercisable, number of shares (in shares) \| shares	0
Options exercisable, weighted average exercise price (in dollars per share) \| $ / shares	$ 0

Consolidated Statements of Stockholders' Equity (Deficit) (Parentheticals) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Conversion of Loan Agreement into Common Stock [Member]
Issuance cost		$ 6
Rights Offering Warrants [Member]
Issuance cost		$ 9
Rights Offering [Member]
Issuance cost	$ 364
ATM Offering [Member]
Issuance cost	24
Issuance cost	$ 1

Note 7 - Commitments and Contingencies

12 Months Ended

Dec. 31, 2024

Commitments and Contingencies Disclosure [Text Block]

7. Commitments and Contingencies

2022 Loan Agreement

On September 20, 2022, the Company and Robert W. Duggan, the Company's majority stockholder and Co-Chairman, entered into a Loan Agreement ("2022 Loan Agreement") in connection with Mr. Duggan lending the principal sum of $65.0 million to the Company. The 2022 Loan Agreement bore interest at a rate per annum equal to 5.0%, payable quarterly commencing on January 1, 2023, with the principal sum payable on March 20, 2024. On March 17, 2023, the Company and Mr. Duggan amended certain terms of the 2022 Loan Agreement. There were no changes to the interest rate, but the principal sum repayment date was changed to September 30, 2024. During the year ended December 31, 2023, the Company made cash payments of $1.7 million for accrued interest on the loan, and recorded an additional $1.1 million of interest expense in relation to the 2022 Loan Agreement. On April 30, 2023, the Company entered into a Securities Purchase Agreement with Mr. Duggan, pursuant to which the Company agreed to issue and sell to Mr. Duggan 10,022,937 shares of the Company’s common stock, par value $0.001 per share, in a Private Placement, at a price per share of $6.51. These shares were paid for through the cancellation of the amounts then owed by the Company under the 2022 Loan Agreement, the principal sum of $65.0 million and all accrued and unpaid interest outstanding, which totaled approximately $0.2 million as of April 30, 2023. The parties completed the Private Placement on May 9, 2023 and, upon closing and satisfaction of the outstanding debt, the 2022 Loan Agreement terminated, without early termination fees or penalties being owed by the Company. There were no additional amounts are owed to Mr. Duggan under the 2022 Loan Agreement at December 31, 2024 and 2023.

Operating Leases

Hayward Lease

In January 2017, the Company entered into a five-year lease (the "Existing Lease") for approximately 15,700 square feet for its principal operating facility located in Hayward, California. The lease commenced during July 2017. In May 2019, the Company entered into Lease Amendment 1 (the "Lease Amendment") in relation to the Existing Lease and added the lease of new premises of approximately 13,300 square feet and 21,300 square feet, (“Expansion Premises 1” and “Expansion Premises 2,” respectively). Additionally, the term of the Existing Lease was extended to October 2029 to be coterminous with Expansion Premises 1 and Expansion Premises 2. The Company evaluated the lease amendment under the provisions of ASC 842. It concluded that the Lease Amendment would be accounted for as a single contract with the Existing Lease because the additional lease payments due to the Lease Amendment was not commensurate with the right-of-use ("ROU") asset granted to the Company. Though the Lease Amendment was accounted for as a single contract, the Existing Premises, Expansion Premises 1 (occupied in November 2019) and Expansion Premises 2 (occupied in May 2020) are accounted for as separate lease components. Accordingly, the Company measured and allocated consideration to each lease component as of the modification date.

Miami Lease

In November 2024, the Company entered into a 65-month lease for approximately 2,000 square feet for its corporate headquarters located in Miami, Florida, which commenced on November 8, 2024. The lease contains one five-year extension option, however, as of the lease commencement date, the Company has determined that it is not reasonably certain to exercise the option to extend the lease and has not included the extension period in the lease term. The monthly lease payment is approximately $0.02 million with annual escalation of approximately 3%. Variable lease costs are comprised primarily of the Company's proportionate share of operating expenses, property taxes, and insurance. Operating lease ROU assets and liabilities on our balance sheet are based on the net present value of the remaining lease payments over the remaining lease term. As the lease did not provide an implicit rate, the Company used its incremental borrowing rate based on the information available in determining the present value of lease payments. The Company’s incremental borrowing rate of 8% was based on the term of the lease, the economic environment of the lease, and reflects the rate the Company would have had to pay to borrow on a secured basis. The Company recorded a ROU asset and lease liability upon lease commencement in the amount of $0.8 million.

During the years ended December 31, 2024 and 2023, total rent expense, including common area maintenance charges, was $2.5 million and $2.3 million, respectively. The variable portion of the lease costs included in the totals were immaterial for the years ended December 31, 2024 and 2023.

Supplemental balance sheet information related to leases (in thousands):

	*Year Ended December 31,*
Assets:	*2024*		*2023*
Operating right-of-use assets	$	7,163	$	7,256

	*Year Ended December 31,*
Liabilities:	*2024*		*2023*
Lease liability, current	$	1,355	$	1,058
Lease liability, less current portion		7,543		8,086
Total lease liabilities	$	8,898	$	9,144

Total cash paid for operating lease liabilities (in thousands):

	*Year Ended December 31,*
	*2024*		*2023*
Cash paid for operating lease liabilities	$	1,938	$	1,845

Maturities of total operating lease liabilities were as follows (in thousands):

Year ending December 31:
2025	$	2,151
2026		2,225
2027		2,302
2028		2,381
2029		2,080
Thereafter		73
Total lease payments		11,212
Less imputed interest		(2,314	)
Total lease liabilities	$	8,898

Weighted-average remaining lease term and discount rate for both the Hayward Lease and Miami Lease, as of December 31, 2024, were as follows:

Weighted-average remaining lease term			4.88
Weighted-average discount rate			9.8	%

Legal Proceedings

From time to time, we may be involved in various legal proceedings arising in the ordinary course of business. Having resolved our earlier dispute with our former Chief Financial Officer, we are not presently a party to any legal proceedings that, in the opinion of management, could have a material adverse effect on our results of operations or financial condition. Regardless of outcome, however, any litigation could have an adverse impact on us because of defense and settlement costs, diversion of management resources, negative publicity, reputational harm, and other factors.

Note 4 - Balance Sheet Components - Schedule of Amortization of Intangible Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
2025	$ 665
2026	555
Finite-Lived Intangible Assets, Net	$ 1,220	$ 1,886

Note 8 - Income Taxes (Tables)

12 Months Ended

Dec. 31, 2024

Schedule of Income before Income Tax, Domestic and Foreign [Table Text Block]

	*Year Ended December 31,*
	*2024*			*2023*
Domestic	$	(53,585	)	$	(42,210	)
Foreign		—			—
	$	(53,585	)	$	(42,210	)

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

	*Year Ended December 31,*
	*2024*			*2023*
Federal tax at statutory rate		21.0	%		21.0	%
Research and development credits		2.2			3.7
Return to provision		(0.3	)		2.6
Change in valuation allowance		(21.8	)		(19.1	)
Deferred adjustment		—			(1.6	)
Change in tax rate		—			(5.8	)
Other		(1.1	)		(0.8	)
Provision for income taxes		—	%		—	%

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

	*December 31,*
	*2024*			*2023*
Deferred tax assets
Accruals	$	1,218		$	1,502
Net operating loss carryforwards		66,952			61,072
Tax credit carryforwards		10,838			9,815
Stock-based compensation		9,588			7,704
R&D capitalization		10,358			7,384
Lease liability		1,869			1,920
Property and equipment		35			7
Intangible assets		279			99
Gross deferred tax assets		101,137			89,503
Valuation allowance		(99,542	)		(87,853	)
Total deferred tax assets		1,595			1,650

Deferred tax liabilities
Right-of-use assets		(1,595	)		(1,650	)
Total deferred tax liabilities		(1,595	)		(1,650	)

Net deferred tax assets/(liabilities)	$	—		$	—

Schedule of Unrecognized Tax Benefits Roll Forward [Table Text Block]

	*December 31,*
	*2024*			*2023*
Unrecognized tax benefits at beginning of year	$	10,170		$	8,925
Increases related to current year tax positions		4,366			1,575
Increases related to prior year tax positions		2,993			1,129
Decreases related to prior year tax positions		(153	)		(1,459	)
Unrecognized tax benefits at end of year	$	17,376		$	10,170

Note 9 - Segment Reporting - Reconciliation of Net Loss (Details) - USD ($)
$ in Thousands

12 Months Ended

Dec. 31, 2024

Dec. 31, 2023

Total revenues

$ 0

Adjusted general and administrative4

23,921

15,777

Total other income, net

2,672

1,364

Net loss

(53,585)

(42,210)

Operating Segments [Member]

Total revenues

Cross platform research and engineering1

^[1]

13,487

15,742

Manufacturing2

^[2]

4,939

2,278

Clinical and regulatory3

^[3]

4,052

2,737

Adjusted general and administrative4

^[4]

15,909

13,317

Sales and marketing5

^[5]

3,106

1,113

Other segment items6

^[6]

14,764

8,387

Total other income, net

(2,672)

(1,364)

Net loss

$ (53,585)

$ (42,210)

[1]	Cross platform research and engineering includes compensation costs, fees paid to consultants and outside service providers and organizations, prototype spending and other expenses relating to the acquisition, design and development of the Company’s clinical stage devices.
[2]	Manufacturing includes compensation costs, fees paid to consultants and outside service providers and organizations, and costs associated with the procurement of materials and the manufacturing of the Company’s clinical stage devices.
[3]	Clinical and regulatory includes compensation costs, fees paid to consultants and outside service providers and organizations, and costs associated with clinical trials and regulatory approvals required for the development of the Company’s clinical stage devices.
[4]	Adjusted general and administrative includes compensation costs and fees paid to consultants and outside service providers and organizations in support of the administrative functions of the Company, including finance, legal and human resources.
[5]	Sales and marketing includes compensation costs, fees paid to consultants and outside service providers and organizations, costs associated with marketing and sales strategy as well as execution of marketing and sales initiatives for the Company's products.
[6]	Other segment items includes stock-based compensation, depreciation and amortization, and facilities and IT costs allocations.

Note 6 - Stockholders' Equity and Stock-based Compensation - Stock-based Compensation Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Total stock-based compensation expense	$ 13,586	$ 7,181
Time-based Options [Member]
Total stock-based compensation expense	10,343	3,827
Performance-based Options [Member]
Total stock-based compensation expense	38	1,977
Market-based Options [Member]
Total stock-based compensation expense	2,926	1,130
Employee Stock Purchase Plan Award [Member]
Total stock-based compensation expense	279	247
Research and Development Expense [Member]
Total stock-based compensation expense	6,293	3,491
General and Administrative Expense [Member]
Total stock-based compensation expense	$ 7,293	$ 3,690

Note 6 - Stockholders' Equity and Stock-based Compensation - Summary of Time-based Option Activity (Details) - Time-based Options [Member] - $ / shares	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Options balances, number of shares (in shares)	6,141,906
Options balances, weighted average exercise price (in dollars per share)	$ 10.48
Options balances, weighted average remaining life (Year)	6 years 8 months 19 days	7 years 25 days
Options granted, number of shares (in shares)	2,124,643
Options granted, weighted average exercise price (in dollars per share)	$ 11.31
Options exercised, number of shares (in shares)	(150,897)
Options exercised, weighted average exercise price (in dollars per share)	$ 5.57
Options canceled, number of shares (in shares)	(605,542)
Options canceled, weighted average exercise price (in dollars per share)	$ 7.59
Options expired, number of shares (in shares)	(34,958)
Options expired, weighted average exercise price (in dollars per share)	$ 20.3
Options modified, number of shares (in shares)	600,113
Options modified, weighted average exercise price (in dollars per share)	$ 4.18
Options balances, number of shares (in shares)	8,075,265	6,141,906
Options balances, weighted average exercise price (in dollars per share)	$ 10.49	$ 10.48
Options exercisable, number of shares (in shares)	4,093,267
Options exercisable, weighted average exercise price (in dollars per share)	$ 13.27
Options exercisable, weighted average remaining life (Year)	4 years 9 months 18 days

Note 6 - Stockholders' Equity and Stock-based Compensation - Option Assumptions (Details)	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Time-based and Performance Options [Member]
Dividend yield	0.00%
Market-based Options [Member]
Expected volatility	90.00%	90.00%
Dividend yield	0.00%
Minimum [Member] \| Time-based and Performance Options [Member]
Expected term in years (Year)	2 years 10 months 24 days	5 years
Expected volatility	91.00%	89.00%
Risk-free interest rate	3.80%	3.70%
Minimum [Member] \| Market-based Options [Member]
Expected term in years (Year)	1 year 4 months 24 days
Risk-free interest rate	3.50%	3.40%
Maximum [Member] \| Time-based and Performance Options [Member]
Expected term in years (Year)	6 years 3 months 18 days	8 years
Expected volatility	99.00%	95.00%
Risk-free interest rate	4.50%	4.40%
Maximum [Member] \| Market-based Options [Member]
Expected term in years (Year)	4 years 3 months 18 days
Risk-free interest rate	3.70%	3.80%

Note 2 - Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2024

Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table Text Block]

	*Year Ended December 31,*
	*2024*		*2023*
Common stock warrants		1,498,483		—
Common stock options		10,979,332		9,466,036
Total		12,477,815		9,466,036

Note 6 - Stockholders' Equity and Stock-based Compensation (Tables)

12 Months Ended

Dec. 31, 2024

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

						*Weighted*
						*Average*
				*Weighted*		*Remaining*
	*Number of*			*Average*		*Contractual*
	*Shares*			*Exercise Price*		*Life (in Years)*
Warrants outstanding at December 31, 2023		—		$	—		—
Issued		5,999,999			11.00
Exercised		(4,501,516	)		11.00
Expired/Redeemed		—			—
Warrants outstanding at December 31, 2024		1,498,483		$	11.00		1.12

Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Table Text Block]

	*Year Ended December 31,*
	*2024*		*2023*
Research and development		6,293		3,491
General and administrative		7,293		3,690
Total stock-based compensation expense	$	13,586	$	7,181

	*Year Ended December 31,*
	*2024*		*2023*
Time-based options	$	10,343	$	3,827
Performance-based options		38		1,977
Market-based options		2,926		1,130
ESPP		279		247
Total stock-based compensation expense	$	13,586	$	7,181

Market-based Options [Member]

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

	*Stock Options Outstanding*
	*Number of shares*			*Weighted average exercise price*		*Weighted average remaining life (in years)*
Balances — December 31, 2023		2,100,000		$	6.78		9.44
Options granted		855,000			8.16
Options exercised		—			—
Options canceled		(700,000	)		7.45
Options expired		—			—
Options modified from performance-based to market-based		206,389			5.39
Balances — December 31, 2024		2,461,389		$	6.95		8.43
Exercisable — December 31, 2024		—			—		—

Share-Based Payment Arrangement, Option [Member]

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

	*Year Ended December 31,*
	*2024*		*2023*
Expected term in years		2.9 - 6.3		5.0 - 8.0
Expected volatility		91% - 99%		89% - 95%
Risk-free interest rate		3.8% - 4.5%		3.7% - 4.4%
Dividend yield		—		—

	*Year Ended December 31,*
	*2024*		*2023*
Expected term in years		1.4 - 4.3		4.0 - 6.3
Expected volatility		90%		90%
Risk-free interest rate		3.5% - 3.7%		3.4% - 3.8%
Dividend yield		—		—

Performance Options [Member]

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

	*Stock Options Outstanding*
	*Number of shares*			*Weighted average exercise price*		*Weighted average remaining life (in years)*
Balances — December 31, 2023		1,224,130		$	5.51		8.53
Options granted		39,000			8.44
Options exercised		(9,950	)		2.92
Options canceled		(3,000	)		2.92
Options expired		(1,000	)		2.92
Options modified from performance-based to time-based and market-based		(806,502	)		4.49
Balances — December 31, 2024		442,678		$	7.71		6.79
Exercisable — December 31, 2024		432,678		$	7.69		6.73

Time-based Options [Member]

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

	*Stock Options Outstanding*
	*Number of shares*			*Weighted average exercise price*		*Weighted average remaining life (in years)*
Balances — December 31, 2023		6,141,906		$	10.48		7.07
Options granted		2,124,643			11.31
Options exercised		(150,897	)		5.57
Options canceled		(605,542	)		7.59
Options expired		(34,958	)		20.30
Options modified from performance-based to time-based		600,113			4.18
Balances — December 31, 2024		8,075,265		$	10.49		6.72
Exercisable — December 31, 2024		4,093,267		$	13.27		4.80

The 2017 Employee Stock Purchase Plan [Member]

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

	*Year Ended December 31,*
	*2024*		*2023*
Expected term in years		0.5 - 1.0		0.5 - 1.0
Expected volatility		98%		83%
Risk-free interest rate		4.4% - 5.3%		5.1% - 5.5%
Dividend yield		—		—

The 2015 Plan, 2017 Plan and Inducement Plan [Member]

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

	*Stock Options Outstanding*
	*Number of shares*			*Weighted average exercise price*		*Weighted average remaining life (in years)*
Balances — December 31, 2023		9,466,036		$	9.01		7.78
Options granted		3,018,643			10.38
Options exercised		(160,847	)		5.41
Options canceled		(1,308,542	)		7.51
Options expired		(35,958	)		19.82
Balances — December 31, 2024		10,979,332		$	9.59		7.11
Exercisable — December 31, 2024		4,525,945		$	12.74		4.98

Note 8 - Income Taxes - Income (Loss) Before Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Domestic	$ (53,585)	$ (42,210)
Foreign	0	0
Loss from operations, before income taxes	$ (53,585)	$ (42,210)

Amount of income (loss) from continuing operations, including income (loss) from equity method investments, before deduction of income tax expense (benefit), and income (loss) attributable to noncontrolling interest.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 22
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482810/280-10-50-22

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 48
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482785/280-10-55-48

Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 32
-Subparagraph (f)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482810/280-10-50-32

Reference 4: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 30
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482810/280-10-50-30

Reference 5: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 270
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (i)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482964/270-10-50-1

Reference 6: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 32
-Subparagraph (ee)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482810/280-10-50-32

Reference 7: http://fasb.org/us-gaap/role/ref/otherTransitionRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 32
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482810/280-10-50-32

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 944
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-04(11))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477250/944-220-S99-1

Reference 9: http://www.xbrl.org/2003/role/exampleRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 31
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482810/280-10-50-31

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Topic 942
-SubTopic 235
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-05(b)(2))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477314/942-235-S99-1

Reference 11: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 220
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03(10))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483621/220-10-S99-2

Reference 12: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 942
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04(15))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478524/942-220-S99-1

Note 11 - Restructuring Charges (Details Textual) $ in Thousands	1 Months Ended	12 Months Ended
	Feb. 28, 2023 USD ($)	Dec. 31, 2024 USD ($)
Restructuring Charges, Statement of Income or Comprehensive Income [Extensible Enumeration]	Costs and Expenses
Employee Severance [Member]
Restructuring and Related Cost, Number of Positions Eliminated	7
Restructuring Charges	$ 100	$ 0

Note 6 - Stockholders' Equity and Stock-based Compensation - Summary of Stock Option Activity (Details) - The 2015 Plan, 2017 Plan and Inducement Plan [Member] - $ / shares	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Options balances, number of shares (in shares)	9,466,036
Options balances, weighted average exercise price (in dollars per share)	$ 9.01
Options balances, weighted average remaining life (Year)	7 years 1 month 9 days	7 years 9 months 10 days
Options granted, number of shares (in shares)	3,018,643
Options granted, weighted average exercise price (in dollars per share)	$ 10.38
Options exercised, number of shares (in shares)	(160,847)
Options exercised, weighted average exercise price (in dollars per share)	$ 5.41
Options canceled, number of shares (in shares)	(1,308,542)
Options canceled, weighted average exercise price (in dollars per share)	$ 7.51
Options expired, number of shares (in shares)	(35,958)
Options expired, weighted average exercise price (in dollars per share)	$ 19.82
Options balances, number of shares (in shares)	10,979,332	9,466,036
Options balances, weighted average exercise price (in dollars per share)	$ 9.59	$ 9.01
Options exercisable, number of shares (in shares)	4,525,945
Options exercisable, weighted average exercise price (in dollars per share)	$ 12.74
Options exercisable, weighted average remaining life (Year)	4 years 11 months 23 days

Note 8 - Income Taxes (Details Textual) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Unrecognized Tax Benefits	$ 17,376	$ 10,170	$ 8,925
Unrecognized Tax Benefits that Would Impact Effective Tax Rate	0
Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount	11,700	$ 8,100
Domestic Tax Jurisdiction [Member]
Operating Loss Carryforwards	250,000
Operating Loss Carryforwards, Not Subject to Expiration	224,400
Tax Credit Carryforward, Amount	9,500
State and Local Jurisdiction [Member]
Operating Loss Carryforwards	274,300
Tax Credit Carryforward, Amount	$ 9,300

Note 5 - Goodwill

12 Months Ended

Dec. 31, 2024

Goodwill Disclosure [Text Block]

5. Goodwill

In 2014, the Company acquired three companies (the acquisitions) for aggregate consideration of $5.5 million. In accordance with ASC Topic 805, Business Combinations, the Company recorded goodwill of $2.8 million in connection with the acquisitions, which represents the excess of consideration paid over the fair value of net tangible and intangible assets acquired.

The Company reviews goodwill for impairment annually or whenever changes in circumstances indicate that the carrying amount of goodwill may not be recoverable. Based on the Company’s annual assessment as of December 31, 2024, the Company determined that its goodwill was not impaired.

Note 8 - Income Taxes - Reconciliation of Unrecognized Tax Benefit (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Unrecognized tax benefits at beginning of year	$ 10,170	$ 8,925
Increases related to current year tax positions	4,366	1,575
Increases related to prior year tax positions	2,993	1,129
Decreases related to prior year tax positions	(153)	(1,459)
Unrecognized tax benefits at beginning of year	$ 17,376	$ 10,170

Consolidated Statements of Stockholders' Equity (Deficit) - USD ($) $ in Thousands	Conversion of Loan Agreement into Common Stock [Member] Common Stock [Member]	Conversion of Loan Agreement into Common Stock [Member] Additional Paid-in Capital [Member]	Conversion of Loan Agreement into Common Stock [Member] AOCI Attributable to Parent [Member]	Conversion of Loan Agreement into Common Stock [Member] Retained Earnings [Member]	Conversion of Loan Agreement into Common Stock [Member]	Rights Offering Warrants [Member] Common Stock [Member]	Rights Offering Warrants [Member] Additional Paid-in Capital [Member]	Rights Offering Warrants [Member] AOCI Attributable to Parent [Member]	Rights Offering Warrants [Member] Retained Earnings [Member]	Rights Offering Warrants [Member]	Rights Offering [Member] Common Stock [Member]	Rights Offering [Member] Additional Paid-in Capital [Member]	Rights Offering [Member] AOCI Attributable to Parent [Member]	Rights Offering [Member] Retained Earnings [Member]	Rights Offering [Member]	ATM Offering [Member] Common Stock [Member]	ATM Offering [Member] Additional Paid-in Capital [Member]	ATM Offering [Member] AOCI Attributable to Parent [Member]	ATM Offering [Member] Retained Earnings [Member]	ATM Offering [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	AOCI Attributable to Parent [Member]	Retained Earnings [Member]	Total
Balance (in shares) at Dec. 31, 2022																					37,235,000
Balance at Dec. 31, 2022																					$ 37	$ 292,420	$ 0	$ (294,705)	$ (2,248)
Issuance of common stock as part of debt extinguishment (in shares)	10,023,000
Issuance of common stock as part of debt extinguishment	$ 10	$ 65,233	$ 0	$ 0	$ 65,243
Issuance of common stock pursuant to warrant exercise (in shares)						7,238,000
Issuance of common stock pursuant to warrant exercise						$ 7	$ 14,821	$ 0	$ 0	$ 14,828
Issuance of shares under employee stock purchase plan (in shares)																					347,000
Issuance of shares under employee stock purchase plan																					$ 1	394	0	0	395
Issuance of common stock upon exercise of stock options (in shares)																					301,000
Issuance of common stock upon exercise of stock options																					$ 0	1,171	0	0	1,171
Stock-based compensation expense																					0	7,181	0	0	7,181
Net loss																					$ 0	0	0	(42,210)	(42,210)
Rights offering deemed pro-rata distribution to shareholders (Note 6)																									0
Balance (in shares) at Dec. 31, 2023																					55,144,000
Balance at Dec. 31, 2023																					$ 55	381,220	0	(336,915)	44,360
Issuance of common stock pursuant to warrant exercise (in shares)																					4,502
Issuance of common stock pursuant to warrant exercise																					$ 5	49,511	0	0	49,516
Issuance of shares under employee stock purchase plan (in shares)																					118,000
Issuance of shares under employee stock purchase plan																					$ 0	478	0	0	478
Issuance of common stock upon exercise of stock options (in shares)																					161,000
Issuance of common stock upon exercise of stock options																					$ 0	871	0	0	871
Stock-based compensation expense																					0	13,586	0	0	13,586
Net loss																					0		0	(53,585)	(53,585)
Issuance of shares (in shares)											6,000,000					1,000
Issuance of shares											$ 6	$ 59,630	$ 0	$ 0	$ 59,636	$ 0	$ 0	$ 0	$ 0	$ 0
Issuance of equity-classified subscription rights as part of rights offering (Note 6)																					0	47,700	0	0	47,700
Rights offering deemed pro-rata distribution to shareholders (Note 6)																					$ 0	(47,700)	0	0	(47,700)
Balance (in shares) at Dec. 31, 2024																					65,926,000
Balance at Dec. 31, 2024																					$ 66	$ 505,296	$ 0	$ (390,500)	$ 114,862

Note 7 - Commitments and Contingencies - Information Related to Right-of-use Assets and Lease Liabilities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Operating Lease, Right-of-Use Asset	$ 7,163	$ 7,256
Lease liability, current	1,355	1,058
Lease liability, less current portion	7,543	8,086
Total lease liabilities	8,898	9,144
Cash paid for operating lease liabilities	1,938	$ 1,845
2025	2,151
2026	2,225
2027	2,302
2028	2,381
2029	2,080
Thereafter	73
Total lease payments	11,212
Less imputed interest	$ (2,314)
Weighted-average remaining lease term (Year)	4 years 10 months 17 days
Weighted-average discount rate	9.80%

Note 6 - Stockholders' Equity and Stock-based Compensation (Details Textual) $ / shares in Units, $ in Thousands								1 Months Ended						3 Months Ended	6 Months Ended	9 Months Ended	12 Months Ended
	Feb. 05, 2025 shares	Jul. 03, 2024 USD ($) $ / shares shares	Mar. 28, 2024 USD ($) $ / shares shares	Jan. 01, 2024 USD ($) shares	Apr. 30, 2023 USD ($) $ / shares shares	Jan. 01, 2023 shares	Jun. 09, 2022 USD ($) $ / shares shares	Feb. 04, 2025 USD ($)	Oct. 31, 2024 USD ($) shares	Mar. 31, 2024 shares	Dec. 31, 2023 $ / shares shares	May 31, 2021 shares	Nov. 30, 2017 shares	Mar. 27, 2025 USD ($)	Jun. 15, 2023 USD ($) shares	Sep. 30, 2024 USD ($)	Dec. 31, 2024 USD ($) $ / shares shares	Dec. 31, 2023 USD ($) $ / shares shares	Dec. 31, 2017 shares	Jan. 02, 2025 shares	Sep. 30, 2023 shares
Preferred Stock, Shares Authorized (in shares)											50,000,000						50,000,000	50,000,000
Preferred Stock, Par or Stated Value Per Share (in dollars per share) \| $ / shares											$ 0.001						$ 0.001	$ 0.001
Preferred Stock, Shares Outstanding, Ending Balance (in shares)											0						0	0
Common Stock, Shares Authorized (in shares)											500,000,000						500,000,000	500,000,000
Common Stock, Par or Stated Value Per Share (in dollars per share) \| $ / shares											$ 0.001						$ 0.001	$ 0.001
Equity Classified Subscription, Value \| $																	$ 47,700
Right Offering Deemed Dividend \| $																	$ 47,700	$ 0
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) \| $ / shares											$ 0						$ 11	$ 0
Class of Warrant or Right, Expired/Redeemed During Period (in shares)																	(0)
Class of Warrant or Right, Outstanding (in shares)											0						1,498,483	0
Proceeds from Warrant Exercises \| $																	$ 49,424	$ 14,828
Class of Warrant or Right, Exercised During Period (in shares)																	4,501,516
Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount \| $				$ 34,800
Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition (Year)				2 years 10 months 6 days
Time-based Options [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Exercises in Period, Intrinsic Value \| $																	$ 1,900	900
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Intrinsic Value \| $																	18,700	9,000
Share-Based Payment Arrangement, Plan Modification, Incremental Cost \| $																	2,900
Modified Time Based Awards [Member]
Share Based Compensation Arrangement By Share Based Payment Award, Shares Modified (in shares)									600,113
Share Based Compensation Arrangement By Share Based Payment Award, Fair Value of Shares Modified \| $									$ 8,800
Share-Based Payment Arrangement, Plan Modification, Incremental Cost \| $																	2,900
Performance-based Options [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Intrinsic Value \| $																$ 300		2,000
Share-Based Payment Arrangement, Plan Modification, Incremental Cost \| $									$ 3,200
Market-based Options [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Intrinsic Value \| $																	5,300	$ 10,500
Modified Market Based Awards [Member]
Share Based Compensation Arrangement By Share Based Payment Award, Shares Modified (in shares)									206,389
Share Based Compensation Arrangement By Share Based Payment Award, Fair Value of Shares Modified \| $																	2,800
Share-Based Payment Arrangement, Plan Modification, Incremental Cost \| $																	$ 400
The 2017 Plan [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Expiration Period (Year)																			10 years
Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Shares Authorized (in shares)																			1,500,000
Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Additional Shares Authorized (in shares)				1,200,000		1,200,000					1,375,000
Increase in Shares Available for Issuance, Threshold of Common Stock Outstanding, Number of Shares (in shares)																			1,200,000
Increase in Shares Available for Issuance, Threshold of Common Stock Outstanding, Percent																			4.00%
Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Shares Available for Grant (in shares)																	77,490
The 2017 Inducement Equity Incentive Plan [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Expiration Period (Year)													10 years
Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Shares Authorized (in shares)													1,000,000
Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Additional Shares Authorized (in shares)										2,000,000		1,000,000
Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Shares Available for Grant (in shares)																	2,941,626
The 2017 Employee Stock Purchase Plan [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Shares Authorized (in shares)																			250,000
Increase in Shares Available for Issuance, Threshold of Common Stock Outstanding, Number of Shares (in shares)																			450,000
Increase in Shares Available for Issuance, Threshold of Common Stock Outstanding, Percent																			1.50%
Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Shares Available for Grant (in shares)																	445,779
Common Stock, Capital Shares Reserved for Future Issuance (in shares)																	450,000
Stock Issued During Period, Shares, Employee Stock Purchase Plans (in shares)																	117,539	347,681
Share-Based Payment Arrangement, Tranche One [Member] \| Time-based Options [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Rights, Percentage																	25.00%
Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Period (Year)																	1 year
Share-Based Payment Arrangement, Tranche One [Member] \| The 2017 Inducement Equity Incentive Plan [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Rights, Percentage													25.00%
Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Period (Year)													1 year
Chief Executive Officer [Member] \| Time-based Options [Member]
Share-Based Payment Arrangement, Accelerated Cost \| $																	$ 700	$ 600
Loan Agreement [Member]
Debt Instrument, Decrease, Forgiveness \| $					$ 65,000
Maximum [Member] \| Modified Time Based Awards [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Period (Year)									4 years
Maximum [Member] \| The 2017 Inducement Equity Incentive Plan [Member] \| Share-Based Payment Arrangement, Option [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Expiration Period (Year)													10 years
Minimum [Member] \| Modified Time Based Awards [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Period (Year)									2 years
Warrants Issued in 2024 Rights Offering [Member]
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right (in shares)		0.5	0.5
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares)		5,999,999
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) \| $ / shares		$ 11
Class of Warrans or Right, Exercise Price, Percentage of Subscription Price for Units		110.00%
Warrants and Rights Outstanding, Term (Year)		5 years
Proceeds from Warrant Exercises \| $																	$ 49,400
Warrants Issued in 2024 Rights Offering [Member] \| Vesting of First Half [Member]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares)																	253,246
Class of Warrants or Rights, Redemption Price Per Share (in dollars per share) \| $ / shares		$ 0.01
Class of Warrant or Right, Percentage Required for Redemption		150.00%															150.00%
Class of Warrant or Right, Vesting, Stock Price Trigger (in dollars per share) \| $ / shares		$ 16.5															$ 18.85
Class of Warrant or Right, Period of Written Notice for Exercise (Day)		30 days
Warrants Issued in 2024 Rights Offering [Member] \| Vesting of First Half [Member] \| Subsequent Event [Member]
Class of Warrant or Right, Percentage Required for Redemption	150.00%
Class of Warrant or Right, Expired/Redeemed During Period (in shares)	18,221
Class of Warrant or Right, Outstanding (in shares)	0
Proceeds from Warrant Exercises \| $								$ 2,600
Warrants Issued in 2024 Rights Offering [Member] \| Vesting of Second Half [Member]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares)																	1,245,237
Class of Warrants or Rights, Redemption Price Per Share (in dollars per share) \| $ / shares		$ 0.01
Class of Warrant or Right, Percentage Required for Redemption		200.00%															200.00%
Class of Warrant or Right, Vesting, Stock Price Trigger (in dollars per share) \| $ / shares		$ 22
Class of Warrant or Right, Period of Written Notice for Exercise (Day)		30 days
Warrants Issued in 2024 Rights Offering [Member] \| Vesting of Second Half [Member] \| Subsequent Event [Member]
Class of Warrant or Right, Percentage Required for Redemption														200.00%
Proceeds from Warrant Exercises \| $														$ 11,400
Warrants Issued in 2024 Rights Offering [Member] \| Maximum [Member]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares)		6,000,000
Rights Offering Warrants [Member]
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right (in shares)							1
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares)							7,317,072				7,317,072							7,317,072
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) \| $ / shares							$ 2.05				$ 2.05							$ 2.05
Class of Warrants or Rights, Redemption Price Per Share (in dollars per share) \| $ / shares							0.01				$ 0.01							$ 0.01
Class of Warrant or Right, Percentage Required for Redemption											200.00%							200.00%
Class of Warrant or Right, Outstanding (in shares)																					0
Proceeds from Warrant Exercises \| $															$ 14,900
Class of Warrant or Right, Period of Written Notice for Exercise (Day)																		30 days
Class of Warrant or Right, Exercise, Consecutive Trading Days (Day)																		20 days
Class of Warrant or Right, Exercised During Period (in shares)															7,250,897			66,175
Rights Offering Warrants [Member] \| Majority Stockholder and Co-chairman [Member] \| Vesting of First Half [Member] \| Subsequent Event [Member]
Class of Warrant or Right, Percentage Required for Redemption																				150.00%
Class of Warrant or Right, Outstanding (in shares)																				0
Rights Offering Warrants [Member] \| Majority Stockholder and Co-chairman [Member] \| Vesting of Second Half [Member] \| Subsequent Event [Member]
Class of Warrant or Right, Percentage Required for Redemption																				200.00%
Class of Warrant or Right, Outstanding (in shares)																				0
The 2024 Right Offering [Member]
Common Stock, Par or Stated Value Per Share (in dollars per share) \| $ / shares		$ 0.001	$ 0.001
Equity Offering, Units, Maximum Amount Authorized (in shares)		6,000,000	6,000,000
Equity Offering Units, Offering Value \| $			$ 60,000
Shares Issued, Price Per Share (in dollars per share) \| $ / shares		$ 10	$ 10
Subscription Right, Number of Units			0.10864186
Number of Shares Per Unit Issued (in shares)		1	1
Number of Warrants in Each Unit (in shares)		2	2
Share Price (in dollars per share) \| $ / shares			$ 11.55
Equity Classified Subscription, Value \| $			$ 47,700
Right Offering Deemed Dividend \| $			$ 47,700
Stock Issued During Period, Shares, New Issues (in shares)		5,999,998
Proceeds from Issuance or Sale of Equity \| $		$ 60,000
The 2024 Right Offering [Member] \| Majority Stockholder and Co-chairman [Member]
Percent of Offering Purchased		88.00%
Private Placement [Member] \| Majority Stockholder and Co-chairman [Member]
Common Stock, Par or Stated Value Per Share (in dollars per share) \| $ / shares					$ 0.001
Shares Issued, Price Per Share (in dollars per share) \| $ / shares					$ 6.51
Stock Issued During Period, Shares, New Issues (in shares)					10,022,937
Rights Offering [Member]
Common Stock, Par or Stated Value Per Share (in dollars per share) \| $ / shares							0.001
Shares Issued, Price Per Share (in dollars per share) \| $ / shares							$ 2.05
Number of Shares Per Unit Issued (in shares)							1
Stock Issued During Period, Shares, New Issues (in shares)							7,317,072
Proceeds from Issuance or Sale of Equity \| $							$ 15,000
Equity Offering, Units, Sale of Units (in shares)							7,317,072
Number of Warrants Per Unit (in shares)							1
Rights Offering [Member] \| Majority Stockholder and Co-chairman [Member]
Percent of Offering Purchased							56.00%

Note 8 - Income Taxes - Reconciliation of Provision for Income Taxes (Details)	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Federal tax at statutory rate	21.00%	21.00%
Research and development credits	2.20%	3.70%
Return to provision	(0.30%)	2.60%
Change in valuation allowance	(21.80%)	(19.10%)
Deferred adjustment	0.00%	(1.60%)
Change in tax rate	0.00%	(5.80%)
Other	(1.10%)	(0.80%)
Provision for income taxes	0.00%	0.00%

Note 13 - Subsequent Events (Details Textual) - USD ($) $ / shares in Units, $ in Thousands			1 Months Ended			3 Months Ended	6 Months Ended	12 Months Ended
	Feb. 05, 2025	Jul. 03, 2024	Feb. 28, 2025	Feb. 04, 2025	Jan. 31, 2025	Mar. 27, 2025	Jun. 15, 2023	Dec. 31, 2024	Dec. 31, 2023	Jan. 02, 2025	Sep. 30, 2023	Jun. 09, 2022
Class of Warrant or Right, Expired/Redeemed During Period (in shares)								(0)
Class of Warrant or Right, Outstanding (in shares)								1,498,483	0
Proceeds from Warrant Exercises								$ 49,424	$ 14,828
Time-based Options [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Gross (in shares)								2,124,643
Share-Based Compensation Arrangements by Share-Based Payment Award, Options, Grants in Period, Weighted Average Exercise Price (in dollars per share)								$ 11.31
Subsequent Event [Member] \| Chief Executive Officer [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Gross (in shares)					1,500,000
Share-Based Compensation Arrangements by Share-Based Payment Award, Options, Grants in Period, Weighted Average Exercise Price (in dollars per share)					$ 18.43
Subsequent Event [Member] \| Chief Executive Officer [Member] \| Time-based Options [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Gross (in shares)					450,000
Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Period (Year)					4 years
Subsequent Event [Member] \| Chief Executive Officer [Member] \| Performance-based and Market-based Options [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Gross (in shares)					1,050,000
Subsequent Event [Member] \| Chief Financial Officer [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Gross (in shares)			300,000
Share-Based Compensation Arrangements by Share-Based Payment Award, Options, Grants in Period, Weighted Average Exercise Price (in dollars per share)			$ 20.93
Subsequent Event [Member] \| Chief Financial Officer [Member] \| Time-based Options [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Gross (in shares)			150,000
Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Period (Year)			4 years
Subsequent Event [Member] \| Chief Financial Officer [Member] \| Performance-based and Market-based Options [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Gross (in shares)			150,000
Warrants Issued in 2024 Rights Offering [Member]
Proceeds from Warrant Exercises								$ 49,400
Warrants Issued in 2024 Rights Offering [Member] \| Vesting of First Half [Member]
Class of Warrants or Rights, Redemption Price Per Share (in dollars per share)		$ 0.01
Class of Warrant or Right, Period of Written Notice for Exercise (Day)		30 days
Class of Warrant or Right, Percentage Required for Redemption		150.00%						150.00%
Class of Warrant or Right, Vesting, Stock Price Trigger (in dollars per share)		$ 16.5						$ 18.85
Warrants Issued in 2024 Rights Offering [Member] \| Vesting of First Half [Member] \| Subsequent Event [Member]
Class of Warrant or Right, Percentage Required for Redemption	150.00%
Class of Warrant or Right, Expired/Redeemed During Period (in shares)	18,221
Class of Warrant or Right, Outstanding (in shares)	0
Proceeds from Warrant Exercises				$ 2,600
Warrants Issued in 2024 Rights Offering [Member] \| Vesting of Second Half [Member]
Class of Warrants or Rights, Redemption Price Per Share (in dollars per share)		$ 0.01
Class of Warrant or Right, Period of Written Notice for Exercise (Day)		30 days
Class of Warrant or Right, Percentage Required for Redemption		200.00%						200.00%
Class of Warrant or Right, Vesting, Stock Price Trigger (in dollars per share)		$ 22
Warrants Issued in 2024 Rights Offering [Member] \| Vesting of Second Half [Member] \| Subsequent Event [Member]
Class of Warrant or Right, Percentage Required for Redemption						200.00%
Proceeds from Warrant Exercises						$ 11,400
Warrants and Rights Outstanding						$ 2,300
Rights Offering Warrants [Member]
Class of Warrants or Rights, Redemption Price Per Share (in dollars per share)									$ 0.01			$ 0.01
Class of Warrant or Right, Period of Written Notice for Exercise (Day)									30 days
Class of Warrant or Right, Percentage Required for Redemption									200.00%
Class of Warrant or Right, Outstanding (in shares)											0
Proceeds from Warrant Exercises							$ 14,900
Rights Offering Warrants [Member] \| Vesting of First Half [Member] \| Subsequent Event [Member] \| Majority Stockholder and Co-chairman [Member]
Class of Warrant or Right, Percentage Required for Redemption										150.00%
Class of Warrant or Right, Outstanding (in shares)										0
Rights Offering Warrants [Member] \| Vesting of Second Half [Member] \| Subsequent Event [Member] \| Majority Stockholder and Co-chairman [Member]
Class of Warrant or Right, Percentage Required for Redemption										200.00%
Class of Warrant or Right, Outstanding (in shares)										0

Note 4 - Balance Sheet Components - Accrued Expenses (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Compensation expense	$ 4,097	$ 3,199
Legal settlement	1,196	0
Severance	698	0
Professional fees	564	343
Clinical trial fees and costs	284	84
Other	188	188
Accrued Liabilities, Current	$ 7,027	$ 3,814

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Current assets:
Cash and cash equivalents	$ 118,038	$ 44,365
Prepaid expenses and other current assets	1,411	963
Total current assets	119,449	45,328
Property and equipment, net	1,160	1,528
Intangible assets, net	1,220	1,886
Goodwill	2,791	2,791
Right-of-use assets	7,163	7,256
Other assets	677	365
Total assets	132,460	59,154
Current liabilities:
Accounts payable	1,673	1,836
Accrued expenses	7,027	3,814
Lease liability, current	1,355	1,058
Total current liabilities	10,055	6,708
Lease liability, less current portion	7,543	8,086
Total liabilities	17,598	14,794
Commitments and contingencies (Note 7)
Stockholders’ equity:
Preferred stock, $0.001 par value; authorized – 50,000 shares; no shares issued and outstanding	0	0
Common stock, $0.001 par value; authorized – 500,000 shares; issued and outstanding – 65,926 shares and 55,144 shares at December 31, 2024 and 2023, respectively	66	55
Additional paid-in capital	505,296	381,220
Accumulated other comprehensive income (loss)	0	0
Accumulated deficit	(390,500)	(336,915)
Total stockholders’ equity	114,862	44,360
Total liabilities and stockholders’ equity	$ 132,460	$ 59,154

Consolidated Statements of Operations and Comprehensive Loss - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Revenues:
Total revenues	$ 0	$ 0
Cost and expenses:
Research and development	32,336	27,797
General and administrative	23,921	15,777
Total cost and expenses	56,257	43,574
Loss from operations	(56,257)	(43,574)
Other income:
Interest income, net	2,672	1,364
Total other income	2,672	1,364
Loss from operations, before income taxes	(53,585)	(42,210)
Income tax provision	0	0
Net loss	(53,585)	(42,210)
Comprehensive loss	$ (53,585)	$ (42,210)
Net loss per share:
Basic and diluted net loss per share (in dollars per share)	$ (0.92)	$ (0.85)
Weighted average shares used to compute net loss per common share — basic and diluted (in shares)	58,398	49,737

Note 6 - Stockholders' Equity and Stock-based Compensation - Summary of Performance Option Activity (Details) - Performance Options [Member] - $ / shares	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Options balances, number of shares (in shares)	1,224,130
Options balances, weighted average exercise price (in dollars per share)	$ 5.51
Options balances, weighted average remaining life (Year)	6 years 9 months 14 days	8 years 6 months 10 days
Options granted, number of shares (in shares)	39,000
Options granted, weighted average exercise price (in dollars per share)	$ 8.44
Options exercised, number of shares (in shares)	(9,950)
Options exercised, weighted average exercise price (in dollars per share)	$ 2.92
Options canceled, number of shares (in shares)	(3,000)
Options canceled, weighted average exercise price (in dollars per share)	$ 2.92
Options expired, number of shares (in shares)	(1,000)
Options expired, weighted average exercise price (in dollars per share)	$ 2.92
Options modified from performance-based to time-based and market-based, number of shares (in shares)	(806,502)
Options modified, weighted average exercise price (in dollars per share)	$ 4.49
Options balances, number of shares (in shares)	442,678	1,224,130
Options balances, weighted average exercise price (in dollars per share)	$ 7.71	$ 5.51
Options exercisable, number of shares (in shares)	432,678
Options exercisable, weighted average exercise price (in dollars per share)	$ 7.69
Options exercisable, weighted average remaining life (Year)	6 years 8 months 23 days

Note 4 - Balance Sheet Components (Details Textual) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Depreciation	$ 512	$ 542
Finite-Lived Intangible Asset, Useful Life (Year)	12 years

Note 3 - Fair Value of Financial Instruments

12 Months Ended

Dec. 31, 2024

Fair Value Disclosures [Text Block]

3. Fair Value of Financial Instruments

Fair Value of Financial Instruments

The Company determines the fair value of its financial instruments based on a fair value hierarchy that prioritizes the inputs to valuation techniques used to measure fair value into three levels:

Level 1 – Observable inputs such as quoted prices in active markets for an identical asset or liability that the Company has the ability to access as of the measurement date. Financial assets and liabilities utilizing Level 1 inputs include money market funds.

Level 2 – Inputs, other than quoted prices included within Level 1, which are directly observable for the asset or liability or indirectly observable through corroboration with observable market data. The Company did not classify any of its investments within Level 2 of the fair value hierarchy.

Level 3 – Unobservable inputs for which there is little or no market data for the asset or liability which requires the reporting entity to develop its own assumptions. The Company did not classify any of its investments within Level 3 of the fair value hierarchy.

The following table sets forth the fair value of the Company’s financial assets measured on a recurring basis (in thousands):

		*December 31, 2024*
Assets	*Classification*	*Level 1*		*Level 2*		*Level 3*		*Total*
Money market funds	Cash and cash equivalents	$	113,776	$	—	$	—	$	113,776
Total assets measured at fair value		$	113,776	$	—	$	—	$	113,776

		*December 31, 2023*
Assets	*Classification*	*Level 1*		*Level 2*		*Level 3*		*Total*
Money market funds	Cash and cash equivalents	$	41,184	$	—	$	—	$	41,184
Total assets measured at fair value		$	41,184	$	—	$	—	$	41,184

During the years ended December 31, 2024 and 2023, the Company did not record impairment charges related to its cash equivalents. During the years ended December 31, 2024 and 2023, the Company did not have any transfers between Level 1, Level 2 or Level 3 of the fair value hierarchy. Additionally, the Company did not have any financial liabilities measured on a recurring basis as of December 31, 2024 or 2023.

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

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Note 2 - Summary of Significant Accounting Policies

12 Months Ended

Dec. 31, 2024

Significant Accounting Policies [Text Block]

2. Summary of Significant Accounting Policies

Principles of Consolidation

The accompanying consolidated financial statements are prepared in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”) and pursuant to the rules and regulations of the United States Securities Exchange Commission (the “SEC”). The consolidated financial statements include the financial statements of the Company and its wholly-owned subsidiaries and intercompany balances and transactions have been eliminated in consolidation.

Use of Estimates

The preparation of financial statements in conformity with U.S. GAAP requires the Company to make estimates that affect the amounts reported in the financial statements and accompanying notes to the financial statements. Estimates include, but are not limited to, the valuation and recognition of stock-based compensation, the valuation of equity-classified subscription rights, income taxes, and the useful lives assigned to long-lived assets. The Company evaluates its estimates and assumptions based on historical experience and other factors and adjusts those estimates and assumptions when facts and circumstances dictate. Actual results could differ materially from these estimates.

Concentration of Credit Risk

Financial instruments that potentially subject the Company to a concentration of credit risk consist of cash and cash equivalents. The Company places its cash equivalents with high credit quality financial institutions and, by policy, limits the amounts invested with any one financial institution or issuer. Deposits held with banks may exceed the amount of insurance provided on such deposits. The Company has not experienced any losses since inception.

Fair Value of Financial Instruments

The Company believes the carrying amounts of its financial instruments, including cash equivalents, prepaid expenses and other current assets, accounts payable and accrued expenses, approximate fair value due to the short-term nature of such instruments.

Cash and Cash Equivalents

The Company invests its cash primarily in money market funds. The Company considers all highly liquid investments purchased with an original maturity of three months or less to be cash equivalents.

Property and Equipment

Property and Equipment is recorded at cost and depreciated using the straight-line method over their estimated useful lives, ranging from three to five years. Leasehold improvements are amortized using the straight-line method over the shorter of the lease term or estimated useful life. Upon the sale or retirement of property and equipment, the costs and related accumulated depreciation and amortization are removed from the balance sheet and the resulting gain or loss is reflected in operating expenses. Maintenance and repairs are charged to operations as incurred.

Intangible Assets

The Company’s intangible assets consist of acquired patents and licenses, which are amortized over their estimated useful lives of twelve years.

Long-Lived Assets

The Company reviews long-lived assets, consisting of property and equipment and intangible assets, for impairment during each fiscal year or when events or changes in circumstances indicate the carrying value of these assets may exceed their current fair values. Recoverability of assets to be held and used is measured by a comparison of the carrying amount of an asset to the estimated undiscounted future cash flows expected to be generated by the asset. No impairment losses were incurred during the periods presented.

Goodwill

The Company records goodwill when the consideration paid in a business acquisition exceeds the fair value of the net tangible assets and the identified intangible assets acquired. The Company reviews goodwill for impairment at the reporting unit level, of which there is one reportable unit, at least annually or whenever changes in circumstances indicate that the carrying value of the goodwill may not be recoverable. To date, there has been no impairment of goodwill.

Stock-Based Compensation

The Company's stock-based compensation programs include stock options and an employee stock purchase program.

The Company periodically issues stock options to officers, directors, employees, and consultants for services rendered. Such issuances vest and expire according to terms established at the issuance date. Stock-based payments to officers, directors and employees, including grants of employee stock options, are recognized in the financial statements based on their grant date fair values, which are estimated using the Black-Scholes option-pricing model. Stock-based compensation expense is charged to operations on a straight-line basis over the vesting period. The Company has granted stock options with both time-based as well as performance-based vesting conditions. For stock awards with performance-based vesting conditions, the Company does not recognize compensation expense until it is probable that the performance-based vesting condition will be achieved. The analysis to determine such probability involves estimates and judgements from management and the estimate of expense may be revised periodically. In October 2024, the Board approved changes to the vesting conditions of certain outstanding common stock option awards so that the performance-based vesting criteria of those particular awards were modified to either time-based or market-based vesting criteria.

During 2024, the Company issued certain stock options with market-based vesting conditions and modified certain performance-based stock option awards to market-based options. These vesting conditions relate to the achievement of certain market capitalization targets of the Company. Using a Monte Carlo simulation model, the Company estimated the fair value of the market-based options on the grant date or modification date, with the associated stock-based compensation expense recognized over the requisite service period. The requisite service period is the service period derived from the Monte Carlo simulation model. If the market capitalization targets are met sooner than the derived service period, the Company will accelerate the recognition of stock-based compensation expense to reflect the cumulative expense associated with the vested shares. The Monte Carlo simulation model requires the Company to make assumptions and judgements about the variables used in the calculation including the expected volatility, the risk-free interest rate, cost of equity, and the expected term. The assumptions used in the option-pricing model represent management’s best estimates. If factors change and different assumptions are used, the Company's stock-based compensation expense could be materially different in the future.

See Note 6 for a detailed discussion of the Company’s stock plans and stock-based compensation expense.

Research and Development Costs

Research and development costs consist primarily of compensation costs, fees paid to consultants and outside service providers and organizations (including university research institutes), costs associated with clinical trials, development prototypes and other expenses relating to the acquisition, design, development and testing of the Company’s product candidates, and certain facilities related costs. Research and development costs incurred by the Company are expensed as incurred.

Patent Costs

The Company is the owner of numerous domestic and foreign patents. Due to the significant uncertainty associated with the successful development of one or more commercially viable products based on the Company’s research efforts and any related patent applications, patent costs not related to acquired patents, including patent-related legal fees, filing fees and other costs, including internally generated costs, are expensed as incurred. During both of the years ended December 31, 2024 and 2023, patent costs totaled $0.5 million, respectively. Patent costs are included in general and administrative costs in the consolidated statements of operations and comprehensive loss.

Income Taxes

The Company accounts for income taxes under an asset and liability approach for financial accounting and reporting for income taxes. Accordingly, the Company recognizes deferred tax assets and liabilities for the expected impact of differences between the financial statements and the tax basis of assets and liabilities.

The Company records a valuation allowance to reduce its deferred tax assets to the amount that is more-likely-than-not to be realized. In the event the Company determines that it would be able to realize its deferred tax assets in the future in excess of its recorded amount, an adjustment to the deferred tax assets would be credited to operations in the period such determination was made. Likewise, should the Company determine that it would not be able to realize all or part of its deferred tax assets in the future, an adjustment to the deferred tax assets would be charged to operations in the period such determination was made.

The Company is subject to U.S. federal income taxes and state income taxes in various states. As the Company’s net operating losses have yet to be utilized, previous tax years remain open to examination by federal authorities and other jurisdictions in which the Company currently operates or has operated in the past. The Company is not currently under examination by any tax authority.

The Company accounts for uncertainties in income tax law under a comprehensive model for the financial statement recognition, measurement, presentation and disclosure of uncertain tax positions taken or expected to be taken in income tax returns as prescribed by U.S. GAAP. The tax effects of a position are recognized only if it is more-likely-than-not to be sustained by the taxing authority as of the reporting date. If the tax position is not considered more-likely-than-not to be sustained, then no benefits of the position are recognized. At December 31, 2024 and 2023, the Company had not recorded any liability for uncertain tax positions. The Company includes interest and penalties related to uncertain tax positions as a component of income tax expense.

Comprehensive Loss

The Company displays comprehensive loss, and if applicable its components, as part of the consolidated statements of operations and comprehensive loss. There were no adjustments to comprehensive loss during both of the years ended December 31, 2024 and 2023.

Net Loss per Share

The Company calculates basic net loss per share by dividing net loss by the weighted-average number of shares of common stock outstanding during the period. Diluted net loss per share is computed by giving effect to all potential dilutive common stock equivalents outstanding during the period. For purposes of this calculation, options to purchase common stock and common stock warrants are considered common stock equivalents. Potential common shares that have an anti-dilutive effect (i.e., those that increase income per share or decrease loss per share) are excluded from the calculation of diluted net loss per share.

Based on the Accounting Standards Codification ("ASC") 260-10-55, Earnings Per Share - Implementation Guidance and Illustrations, the Company determined that the 2024 Rights Offering (Note 6), contained a bonus element. A rights offering is deemed to have a bonus element when the exercise price at issuance is less than fair value of the Company's stock. The Company has retroactively adjusted earnings per share and weighted average number of shares outstanding for the bonus element for prior periods presented.

Basic and diluted net loss per common share is the same for all periods presented because all warrants and stock options outstanding are anti-dilutive.

The following outstanding stock options and warrants were excluded from the computation of diluted net loss per share for the periods presented because including them would have had an anti-dilutive effect:

	*Year Ended December 31,*
	*2024*		*2023*
Common stock warrants		1,498,483		—
Common stock options		10,979,332		9,466,036
Total		12,477,815		9,466,036

Segment and Geographical Information

The Company has one operating and reporting segment and reports segment information in accordance with ASC 280, Segment Reporting. The Company’s Chief Executive Officer, who is the chief operating decision maker ("CODM"), reviews financial information on an aggregate basis for allocating and evaluating financial performance; however, the CODM is regularly provided with more detailed expense information than what is included in the Statement of Operations and Comprehensive Loss. See Note 9 for further details of the Company's segment disclosures.

Recent Accounting Pronouncements

Recently Adopted Accounting Pronouncements

In November 2023, the FASB issued ASU 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures. The amendments in this ASU require disclosures, on an annual and interim basis, of significant segment expenses that are regularly provided to the CODM, as well as the aggregate amount of other segment items included in the reported measure of segment profit or loss. This ASU requires that a public entity disclose the title and position of the CODM and an explanation of how the CODM uses the reported measure(s) of segment profit or loss in assessing segment performance and deciding how to allocate resources. Public entities will be required to provide all annual disclosures currently required by Topic 280 in interim periods, and entities with a single reportable segment are required to provide all the disclosures required by the amendments in this ASU and existing segment disclosures in Topic 280. This ASU is effective for fiscal years beginning after December 15, 2023, and interim periods within fiscal years beginning after December 15, 2024, with early adoption permitted. The amendments in this ASU should be applied retrospectively to all prior periods presented in the financial statements. See Note 9 for details of the Company's segment reporting.

Recent Accounting Pronouncements Not Yet Adopted

In December 2023, the FASB issued ASU No. 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures. This ASU requires greater disaggregation of information about a reporting entity's effective tax rate reconciliation as well as information on income taxes paid. This ASU applies to all entities subject to income taxes and is intended to help investors better understand an entity’s exposure to potential changes in jurisdictional tax legislation and assess income tax information that affects cash flow forecasts and capital allocation decisions. This ASU is effective for annual periods beginning after December 15, 2024, with early adoption permitted. This ASU should be applied on a prospective basis although retrospective application is permitted. The Company is currently evaluating the impact the adoption of this ASU will have on its consolidated financial statements and related disclosures.

In March 2024, the FASB issued ASU No. 2024-02, Codification Improvements - Amendments to Remove References to the Concepts Statements, an amendment of the FASB Accounting Standards Codification. The amendments in this ASU are related to the removal of various references to FASB Concept Statements from the codification to make clear distinctions between authoritative and non-authoritative literature in the codification. This ASU is effective for fiscal years beginning after December 15, 2024, with early adoption permitted. The Company does not believe this standard will have an impact on its consolidated financial statements and related disclosures.

In November 2024, the FASB issued ASU 2024-03, Disaggregation of Income Statement Expenses, which aims to improve the disclosures about a public business entity’s expenses and address requests from investors for more detailed information about the types of expenses in commonly presented expense captions. The guidance is effective for the Company's annual periods beginning in 2027 and interim periods beginning in the first quarter of fiscal year 2028. The Company is currently evaluating the impact of the new guidance.

Note 10 - Related Party Transactions

12 Months Ended

Dec. 31, 2024

10. Related Party Transactions

In May 2022, the Company determined not to renew its annual director and officer liability insurance policy due to disproportionately high premiums quoted by insurance companies. Instead, on May 31, 2022, the Company and Robert W. Duggan, majority stockholder and Co-Chairman, entered into a letter agreement (the "Letter Agreement") pursuant to which Mr. Duggan agreed with the Company to personally provide indemnity coverage for a one-year period, and he agreed to deposit cash and/or marketable securities into a third-party escrow, as security for these obligations, if requested by the Company. On May 31, 2023, the last day of the one-year period, the Company paid Mr. Duggan a fee of $1.0 million in consideration of the obligations set forth in the Letter Agreement. As of December 31, 2024, there were no additional amounts owed to Mr. Duggan under the Letter Agreement.

On June 9, 2022, the Company completed the 2022 Rights Offering resulting in the sale of 7,317,072 Units, at a price of $2.05 per Unit, with each Unit consisting of one share of the Company’s common stock, par value $0.001 per share, and one 2022 Rights Offering Warrant to purchase one share of common stock at a price of $2.05 per share. Robert W. Duggan, the Company’s majority stockholder and Co-Chairman, purchased approximately 56% of the shares offered through the 2022 Rights Offering. See Note 6 for further details.

On September 20, 2022, the Company and Robert W. Duggan, the Company's majority stockholder and Co-Chairman, entered into the 2022 Loan Agreement in connection with Mr. Duggan lending the principal sum of $65.0 million to the Company. On April 30, 2023, the Company entered into a Securities Purchase Agreement with Mr. Duggan, pursuant to which the Company agreed to issue and sell to Mr. Duggan 10,022,937 shares of the Company’s common stock, par value $0.001 per share, in a Private Placement, at a price per share of $6.51. These shares were paid for through the cancellation of the amounts then owed by the Company under the 2022 Loan Agreement, the principal sum of $65.0 million and all accrued and unpaid interest outstanding, which totaled approximately $0.2 million as of April 30, 2023. Upon closing of the Private Placement and satisfaction of the outstanding debt, the 2022 Loan Agreement terminated, without early termination fees or penalties being owed by the Company. No additional amounts are owed to Mr. Duggan under the 2022 Loan Agreement. See Note 7 for further details.

On July 3, 2024, the Company announced the closing of its 2024 Rights Offering. The 2024 Rights Offering resulted in the sale of six million 2024 Units, at a price of $10.00 per 2024 Unit. Each 2024 Unit consisted of one share of the Company’s common stock, par value $0.001 per share, and two warrants, each being a warrant to purchase one-half of one share of common stock. The common stock and warrants comprising the 2024 Units separated upon the closing of the 2024 Rights Offering and were issued individually. A total of 5,999,998 shares of common stock and warrants to acquire up to approximately an additional six million shares of common stock were issued in the offering. The Company received aggregate gross proceeds from the 2024 Rights Offering of $60 million. Robert W. Duggan, the Company’s majority stockholder and Co-Chairman, purchased approximately 88% of the units offered through the 2024 Rights Offering. See Note 6 for further details.

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
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Note 12 - Employee Benefit Plans

12 Months Ended

Dec. 31, 2024

Retirement Benefits [Text Block]

12. Employee Benefit Plans

The Company sponsors a defined contribution plan under which it may make discretionary contributions. The Company did not make any employer matching contributions to this plan during the years ended December 31, 2024 and 2023

The entire disclosure for retirement benefits.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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Reference 14: http://www.xbrl.org/2003/role/disclosureRef
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Insider Trading Arrangements	12 Months Ended
Insider Trading Arrangements	Dec. 31, 2024
Trading Arrangements, by Individual [Table]
Material Terms of Trading Arrangement [Text Block]	Item *9B.* Other Information None.
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 12 - Employee Benefit Plans (Details Textual) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Defined Contribution Plan, Employer Discretionary Contribution Amount	$ 0	$ 0

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Cash flows from operating activities:
Net loss	$ (53,585)	$ (42,210)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation	512	542
Amortization of intangible assets	666	665
Stock-based compensation	13,586	7,181
Loss on disposal of fixed assets	6	13
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	(403)	(65)
Other receivables	48	109
Right-of-use assets	923	806
Other long-term assets	(31)	0
Accounts payable	(201)	263
Accrued expenses	3,212	1,219
Lease liabilities	(1,076)	(896)
Accrued interest on related party note payable	0	(668)
Net cash used in operating activities	(36,343)	(33,041)
Cash flows from investing activities:
Purchases of property and equipment	(125)	(121)
Net cash used in investing activities	(125)	(121)
Cash flows from financing activities:
Proceeds from issuance of common stock under employee stock purchase plan	478	395
Proceeds from exercises of warrants	49,424	14,828
Proceeds from exercises of stock options	871	1,171
Proceeds from issuance of common stock and warrants in relation to rights offering, net of issuance costs	59,649	0
Issuance cost in relation to related party note extinguishment	0	(6)
Deferred issuance costs in relation to future at-the-market equity offering	(281)	0
Net cash provided by financing activities	110,141	16,388
Net increase (decrease) in cash and cash equivalents	73,673	(16,774)
Cash and cash equivalents at beginning of period	44,365	61,139
Cash and cash equivalents at end of period	118,038	44,365
Supplemental disclosure of noncash investing and financing activities:
Rights offering deemed pro-rata distribution to shareholders	47,700	0
Principal and accrued interest of related party note settled via issuance of common stock	0	(65,249)
Right-of-use asset obtained in exchange for lease liability	830	0
Other receivable from exercise of warrants	92	0
Equipment purchases included in accounts payable and accrued expenses	26	0
Rights offering and warrant issuance costs in accounts payable and accrued expenses	$ 13	$ 0

Note 3 - Fair Value of Financial Instruments (Details Textual) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Impairment of Marketable Securities	$ 0	$ 0
Fair Value, Level 1, 2 and 3 Transfers, Amount	0	0
Fair Value, Recurring [Member]
Liabilities, Fair Value Disclosure	$ 0	$ 0

Note 2 - Summary of Significant Accounting Policies - Antidilutive Securities (Details) - shares	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Antidilutive securities (in shares)	12,477,815	9,466,036
Warrant [Member]
Antidilutive securities (in shares)	1,498,483	0
Share-Based Payment Arrangement, Option [Member]
Antidilutive securities (in shares)	10,979,332	9,466,036

Note 9 - Segment Reporting

12 Months Ended

Dec. 31, 2024

Segment Reporting Disclosure [Text Block]

9. Segment Reporting

Operating segments are defined as components of an enterprise about which separate discrete information is available for evaluation by the chief operating decision-maker (the "CODM"), in deciding how to allocate resources and assess performance. The Company has one operating and reportable segment relating to the research and development of the Company’s NPS technology. The CODM views the Company’s operations and manages its business in one operating segment. The CODM uses the Company’s consolidated net loss to monitor actual results as compared to the budget in assessing segment performance and allocation of resources. Managing and allocating resources on an entity-wide basis enables the CODM to assess the overall level of resources available and how to best deploy these resources across functions and research and development projects that are in line with the Company’s long-term company-wide strategic goals. Consistent with this decision-making process, the CODM uses financial information for purposes of evaluating performance, forecasting future period financial results, allocating resources, and setting incentive targets. Operating expenses are used to monitor budget versus actual results. The CODM is regularly provided with more detailed expense information than what is included in our Consolidated Statement of Operations and Comprehensive Loss. Throughout 2024, the CODM of the Company changed multiple times, however the financial information that was reviewed by each of the CODMs did not change throughout the year. The table below shows a reconciliation of the Company’s net loss, including the significant expense categories regularly provided to and reviewed by the CODM, as computed under U.S. GAAP to the Company’s total net loss in the statements of operations (in thousands).

	*Year Ended December 31,*
	*2024*			*2023*
Total revenues	$	—		$	—
Cross platform research and engineering¹		13,487			15,742
Manufacturing²		4,939			2,278
Clinical and regulatory³		4,052			2,737
Adjusted general and administrative⁴		15,909			13,317
Sales and marketing⁵		3,106			1,113
Other segment items⁶		14,764			8,387
Total other income, net		(2,672	)		(1,364	)
Net loss	$	(53,585	)	$	(42,210	)

___________________

¹Cross platform research and engineering includes compensation costs, fees paid to consultants and outside service providers and organizations, prototype spending and other expenses relating to the acquisition, design and development of the Company’s clinical stage devices.

²Manufacturing includes compensation costs, fees paid to consultants and outside service providers and organizations, and costs associated with the procurement of materials and the manufacturing of the Company’s clinical stage devices.

³Clinical and regulatory includes compensation costs, fees paid to consultants and outside service providers and organizations, and costs associated with clinical trials and regulatory approvals required for the development of the Company’s clinical stage devices.

⁴Adjusted general and administrative includes compensation costs and fees paid to consultants and outside service providers and organizations in support of the administrative functions of the Company, including finance, legal and human resources.

⁵Sales and marketing includes compensation costs, fees paid to consultants and outside service providers and organizations, costs associated with marketing and sales strategy as well as execution of marketing and sales initiatives for the Company's products.

⁶Other segment items includes stock-based compensation, depreciation and amortization, and facilities and IT costs allocations.

As of December 31, 2024 and 2023, all of the Company’s long-lived assets are located in the United States.

The entire disclosure for reporting segments including data and tables. Reportable segments include those that meet any of the following quantitative thresholds a) it's reported revenue, including sales to external customers and intersegment sales or transfers is 10 percent or more of the combined revenue, internal and external, of all operating segments b) the absolute amount of its reported profit or loss is 10 percent or more of the greater, in absolute amount of 1) the combined reported profit of all operating segments that did not report a loss or 2) the combined reported loss of all operating segments that did report a loss c) its assets are 10 percent or more of the combined assets of all operating segments.

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Consolidation, Policy [Policy Text Block]

Note 10 - Related Party Transactions (Details Textual) - USD ($) $ / shares in Units, $ in Thousands	Jul. 03, 2024	May 31, 2023	Apr. 30, 2023	Jun. 09, 2022	May 31, 2022	Dec. 31, 2024	Sep. 30, 2024	Mar. 28, 2024	Dec. 31, 2023	Sep. 20, 2022
Accrued Liabilities, Current						$ 7,027			$ 3,814
Common Stock, Par or Stated Value Per Share (in dollars per share)						$ 0.001			$ 0.001
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)						$ 11			0
Loan Agreement [Member]
Debt Instrument, Decrease, Forgiveness			$ 65,000
Interest Payable			$ 200
Rights Offering Warrants [Member]
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right (in shares)				1
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)				$ 2.05					$ 2.05
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares)				7,317,072					7,317,072
Warrants Issued in 2024 Rights Offering [Member]
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right (in shares)	0.5							0.5
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)	$ 11
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares)	5,999,999
Warrants Issued in 2024 Rights Offering [Member] \| Maximum [Member]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares)	6,000,000
Rights Offering [Member]
Equity Offering, Units, Sale of Units (in shares)				7,317,072
Shares Issued, Price Per Share (in dollars per share)				$ 2.05
Number of Shares Per Unit Issued (in shares)				1
Common Stock, Par or Stated Value Per Share (in dollars per share)				$ 0.001
Number of Warrants Per Unit (in shares)				1
Stock Issued During Period, Shares, New Issues (in shares)				7,317,072
Proceeds from Issuance or Sale of Equity				$ 15,000
The 2024 Right Offering [Member]
Shares Issued, Price Per Share (in dollars per share)	$ 10							$ 10
Number of Shares Per Unit Issued (in shares)	1							1
Common Stock, Par or Stated Value Per Share (in dollars per share)	$ 0.001							$ 0.001
Stock Issued During Period, Shares, New Issues (in shares)	5,999,998
Equity Offering, Units, Maximum Amount Authorized (in shares)	6,000,000							6,000,000
Number of Warrants in Each Unit (in shares)	2							2
Proceeds from Issuance or Sale of Equity	$ 60,000
Majority Stockholder and Co-chairman [Member] \| Loan Agreement [Member]
Debt Instrument, Face Amount										$ 65,000
Majority Stockholder and Co-chairman [Member] \| Rights Offering [Member]
Investment Owned, Net Assets, Percentage				56.00%
Majority Stockholder and Co-chairman [Member] \| Private Placement [Member]
Shares Issued, Price Per Share (in dollars per share)			$ 6.51
Common Stock, Par or Stated Value Per Share (in dollars per share)			$ 0.001
Stock Issued During Period, Shares, New Issues (in shares)			10,022,937
Majority Stockholder and Co-chairman [Member] \| The 2024 Right Offering [Member]
Percent of Offering Purchased	88.00%
Letter Agreement [Member] \| Majority Stockholder and Co-chairman [Member]
Directors and Officers Liability Insurance, Period (Year)					1 year
Related Party Transaction, Amounts of Transaction		$ 1,000
Accrued Liabilities, Current							$ 0

Note 9 - Segment Reporting (Details Textual)	12 Months Ended
Note 9 - Segment Reporting (Details Textual)	Dec. 31, 2024
Number of Reportable Segments	1
Number of Operating Segments	1

Significant Accounting Policies (Policies)

12 Months Ended

Dec. 31, 2024

Accounting Policies [Abstract]

Principles of Consolidation

Use of Estimates, Policy [Policy Text Block]

Use of Estimates

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

Concentration of Credit Risk

Fair Value of Financial Instruments, Policy [Policy Text Block]

Fair Value of Financial Instruments

Cash and Cash Equivalents, Policy [Policy Text Block]

Cash and Cash Equivalents

The Company invests its cash primarily in money market funds. The Company considers all highly liquid investments purchased with an original maturity of three months or less to be cash equivalents.

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

Property and Equipment

Goodwill and Intangible Assets, Intangible Assets, Policy [Policy Text Block]

Intangible Assets

The Company’s intangible assets consist of acquired patents and licenses, which are amortized over their estimated useful lives of twelve years.

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

Long-Lived Assets

Goodwill and Intangible Assets, Goodwill, Policy [Policy Text Block]

Goodwill

Share-Based Payment Arrangement [Policy Text Block]

Stock-Based Compensation

The Company's stock-based compensation programs include stock options and an employee stock purchase program.

See Note 6 for a detailed discussion of the Company’s stock plans and stock-based compensation expense.

Research and Development Expense, Policy [Policy Text Block]

Research and Development Costs

Patent Costs [Policy Text Block]

Patent Costs

Income Tax, Policy [Policy Text Block]

Income Taxes

Comprehensive Income, Policy [Policy Text Block]

Comprehensive Loss

Earnings Per Share, Policy [Policy Text Block]

Net Loss per Share

Basic and diluted net loss per common share is the same for all periods presented because all warrants and stock options outstanding are anti-dilutive.

	*Year Ended December 31,*
	*2024*		*2023*
Common stock warrants		1,498,483		—
Common stock options		10,979,332		9,466,036
Total		12,477,815		9,466,036

Segment Reporting, Policy [Policy Text Block]

Segment and Geographical Information

New Accounting Pronouncements, Policy [Policy Text Block]

Recent Accounting Pronouncements

Recently Adopted Accounting Pronouncements

Recent Accounting Pronouncements Not Yet Adopted

Note 6 - Stockholders' Equity and Stock-based Compensation - ESPP Assumptions (Details) - The 2017 Employee Stock Purchase Plan [Member]	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Expected volatility	98.00%	83.00%
Dividend yield	0.00%	0.00%
Minimum [Member]
Expected term in years (Year)	6 months	6 months
Risk-free interest rate	4.40%	5.10%
Maximum [Member]
Expected term in years (Year)	1 year	1 year
Risk-free interest rate	5.30%	5.50%

Note 1 - Description of the Business

12 Months Ended

Dec. 31, 2024

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

1. Description of the Business

Pulse Biosciences, Inc. is a novel bioelectric medicine company committed to health innovation using its patented Nano-pulse Stimulation (“NPS”) technology, a revolutionary energy modality that delivers nanosecond-duration pulses of electrical energy, each less than a millionth of a second long, to non-thermally clear targeted cells while sparing adjacent noncellular tissue. NPS technology, also referred to as a Nanosecond Pulsed-Field Ablation (“nsPFA”) technology when used to ablate cellular tissue, can be used to treat a variety of medical conditions for which an optimal solution remains unfulfilled. The Company developed its proprietary CellFX System, a novel nsPFA delivery platform, and commercialized the initial application of its nsPFA technology to treat benign lesions of the skin. In parallel, the Company has designed a variety of applicators to explore the potential use of the CellFX platform to treat disorders in other medical specialties, such as cardiology, gastroenterology, gynecology, and ear nose and throat. These applicators include devices for open surgical procedures, endoscopic or minimally invasive procedures, and endoluminal catheters, and each has been used in preclinical studies. Based on our preclinical experience and the potential to significantly improve outcomes for patients in a large and growing market, the Company decided in 2022 to focus its efforts on the use of nsPFA and the CellFX platform in the treatment of atrial fibrillation (“AF”), and in a select few other markets where nsPFA could have a profound positive impact on healthcare for both patients and providers, such as surgical soft tissue ablation.

The Company was incorporated in Nevada on May 19, 2014. On June 18, 2018, the Company reincorporated from the State of Nevada to the State of Delaware. The Company is headquartered in Miami, Florida, with its principal operating facility located in Hayward, California.

The Company’s activities are subject to significant risks and uncertainties, including the need for additional capital. The Company does not currently have any material cash flows from operations. It has had minimal revenue since inception and will need to raise additional capital to finance its operations. However, there can be no assurances that the Company will be able to obtain additional financing on acceptable terms and in the amounts necessary to fully fund its operating requirements.

Note 8 - Income Taxes

12 Months Ended

Dec. 31, 2024

Income Tax Disclosure [Text Block]

8. Income Taxes

Income (loss) before income taxes (in thousands):

	*Year Ended December 31,*
	*2024*			*2023*
Domestic	$	(53,585	)	$	(42,210	)
Foreign		—			—
	$	(53,585	)	$	(42,210	)

The Company has not recorded any income tax expenses in the Consolidated Statements of Operations and Comprehensive Loss for the years ended December 31, 2024 and 2023.

The provision for income taxes differs from the amount estimated by applying the statutory federal income tax rate to income (loss) before taxes as follows:

	*Year Ended December 31,*
	*2024*			*2023*
Federal tax at statutory rate		21.0	%		21.0	%
Research and development credits		2.2			3.7
Return to provision		(0.3	)		2.6
Change in valuation allowance		(21.8	)		(19.1	)
Deferred adjustment		—			(1.6	)
Change in tax rate		—			(5.8	)
Other		(1.1	)		(0.8	)
Provision for income taxes		—	%		—	%

Deferred income taxes reflect the impact of carryforwards and temporary differences between the amounts of assets and liabilities for financial reporting purposes and such amounts as measured by tax laws. The carryforwards and temporary differences, which give rise to a significant portion of the Company’s deferred tax asset (liability) as of December 31, 2024 and 2023, are as follows (in thousands):

	*December 31,*
	*2024*			*2023*
Deferred tax assets
Accruals	$	1,218		$	1,502
Net operating loss carryforwards		66,952			61,072
Tax credit carryforwards		10,838			9,815
Stock-based compensation		9,588			7,704
R&D capitalization		10,358			7,384
Lease liability		1,869			1,920
Property and equipment		35			7
Intangible assets		279			99
Gross deferred tax assets		101,137			89,503
Valuation allowance		(99,542	)		(87,853	)
Total deferred tax assets		1,595			1,650

Deferred tax liabilities
Right-of-use assets		(1,595	)		(1,650	)
Total deferred tax liabilities		(1,595	)		(1,650	)

Net deferred tax assets/(liabilities)	$	—		$	—

The Company’s unrecognized tax benefits as of December 31, 2024 and 2023 were $17.4 million and $10.2 million, respectively. If recognized, none of the unrecognized tax benefits would impact income tax expense to the extent that the Company continues to maintain a full valuation allowance against its deferred tax assets.

A reconciliation of the beginning and ending amounts of unrecognized tax benefit is as follows (in thousands):

	*December 31,*
	*2024*			*2023*
Unrecognized tax benefits at beginning of year	$	10,170		$	8,925
Increases related to current year tax positions		4,366			1,575
Increases related to prior year tax positions		2,993			1,129
Decreases related to prior year tax positions		(153	)		(1,459	)
Unrecognized tax benefits at end of year	$	17,376		$	10,170

The Company’s policy is to recognize interest and penalties related to income taxes as components of interest expense and other expense, respectively. The Company did not accrue interest and penalties related to unrecognized tax benefits as of December 31, 2024 and does not anticipate any significant change within twelve months of this reporting date.

The Company’s valuation allowance increased by $11.7 million in the year ended December 31, 2024 and increased by $8.1 million in the year ended December 31, 2023.

As of December 31, 2024, the Company had federal and state net operating loss (“NOL”) carryforwards of $250.0 million and $274.3 million, respectively, which begin to expire in 2034. Of the total federal NOL carryforward of $250.0 million, approximately $224.4 million is carried forward indefinitely but is limited to 80% of the taxable income.

As of December 31, 2024, the Company had approximately $9.5 million and $9.3 million of U.S. federal and California research and development (“R&D”) credits, respectively. The federal R&D credits begin to expire in 2035 and the California R&D credits have an indefinite carryforward period.

The Company is subject to taxation in the United States for Federal and for State, within various states in which the Company operates. All jurisdictions and tax years currently remain open for IRS and state taxing authorities’ examination. As of December 31, 2024, the Company was not under examination by the Internal Revenue Service or any state tax jurisdiction.

Internal Revenue Code Section 382 ownership change generally occurs if one or more stockholders or groups of stockholders who own at least 5% of our stock increase their ownership by more than 50 percentage points over their lowest ownership percentage within a rolling three-year period. Similar rules may apply under state tax laws. We believe that we have had one or more ownership changes prior to 2018, but recently performed a Section 382 study to analyze fiscal years 2018 through 2024, and we do not believe that we have had any additional ownership changes over that period. Possible future changes in our stock ownership could result in limitations.

The entire disclosure for income tax.

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