0000950170-24-127014 | 10-Q | XBRL Viewer

Line of Credit Facility	9 Months Ended
Sep. 30, 2024
Line of Credit Facility [Abstract]
Line of Credit Facility	6. Line of Credit Facility On May 31, 2024, the Company drew down $3.3 million on a new margin loan facility under a line of credit (the “Pershing Credit Facility”) with Pershing LLC (“Pershing”), an affiliate of The Bank of New York Mellon Corporation. The available credit line limit under the Pershing Credit Facility fluctuates based on the Company’s request for extensions from time to time, subject to the value of the collateralized marketable securities the Company holds with Pershing, provided that the amount available to draw under the Pershing Credit Facility cannot exceed 91.5% of the value of the collateralized marketable securities deposited with Pershing. Depending on the value of the marketable securities the Company holds with Pershing, Pershing may require the Company from time-to-time to deposit additional funds or marketable securities in order to restore the level of collateral to an acceptable level. The amounts borrowed under the Pershing Credit Facility are due on demand. As of September 30, 2024, the Company held collateralized marketable securities with Pershing with a total value of $3.6 million. Borrowings under the Pershing Credit Facility bear interest at the target interest rate set by the Federal Open Market Committee, subject to a floor of 5.5%, plus a spread of 1.75% and applicable fees of 0.5%, subject to a maximum interest rate of the then applicable Prime Rate as published in The Wall Street Journal plus 3.0%. Interest payments thereunder are calculated on a monthly basis and, unless paid, are added to the outstanding balance under the Pershing Credit Facility. The proceeds under the Pershing Credit Facility are available for working capital needs and other general corporate purposes. Volatility in the global markets could cause the interest rate to fluctuate from time to time increasing the Company’s costs, or could cause Pershing to terminate the Company’s ability to borrow funds. In addition, borrowings under the Pershing Credit Facility have the effect of limiting the Company’s use of cash and marketable securities.

Line of Credit Facility

9 Months Ended

Sep. 30, 2024

6. Line of Credit Facility

On May 31, 2024, the Company drew down $3.3 million on a new margin loan facility under a line of credit (the “Pershing Credit Facility”) with Pershing LLC (“Pershing”), an affiliate of The Bank of New York Mellon Corporation. The available credit line limit under the Pershing Credit Facility fluctuates based on the Company’s request for extensions from time to time, subject to the value of the collateralized marketable securities the Company holds with Pershing, provided that the amount available to draw under the Pershing Credit Facility cannot exceed 91.5% of the value of the collateralized marketable securities deposited with Pershing. Depending on the value of the marketable securities the Company holds with Pershing, Pershing may require the

Company from time-to-time to deposit additional funds or marketable securities in order to restore the level of collateral to an acceptable level. The amounts borrowed under the Pershing Credit Facility are due on demand. As of September 30, 2024, the Company held collateralized marketable securities with Pershing with a total value of $3.6 million.

Borrowings under the Pershing Credit Facility bear interest at the target interest rate set by the Federal Open Market Committee, subject to a floor of 5.5%, plus a spread of 1.75% and applicable fees of 0.5%, subject to a maximum interest rate of the then applicable Prime Rate as published in The Wall Street Journal plus 3.0%. Interest payments thereunder are calculated on a monthly basis and, unless paid, are added to the outstanding balance under the Pershing Credit Facility. The proceeds under the Pershing Credit Facility are available for working capital needs and other general corporate purposes. Volatility in the global markets could cause the interest rate to fluctuate from time to time increasing the Company’s costs, or could cause Pershing to terminate the Company’s ability to borrow funds. In addition, borrowings under the Pershing Credit Facility have the effect of limiting the Company’s use of cash and marketable securities.

Fair Value Measurements (Tables)

9 Months Ended

Sep. 30, 2024

Fair Value Disclosures [Abstract]

Summary of Financial Assets Measured at Fair Value on Recurring Basis

The following table summarizes the Company’s fair value hierarchy for its financial assets measured at fair value on a recurring basis as of September 30, 2024 and December 31, 2023, respectively (in thousands).


	Fair Value Measurements Using
September 30, 2024	Fair Value		Level 1		Level 2		Level 3
Money market	$	1,196	$	1,196	$	—	$	—
Treasury bills and government agency bonds		3,565		—		3,565		—
	$	4,761	$	1,196	$	3,565	$	—

	Fair Value Measurements Using
December 31, 2023	Fair Value		Level 1		Level 2		Level 3
Money market	$	5,449	$	5,449	$	—	$	—

Summary of Key Inputs Used in Valuation of Liability Classified Warrants

The table below summarizes key inputs used in the valuation of the liability classified warrants as of the issuance date and as of the date of amendment:


	As of issuance date	As of date of amendment
Expected term	1.1 - 5.0 years	0.9 - 4.7 years
Common stock market price	$2.01 - $2.27	$	1.45
Risk-free interest rate	4.5% - 5.1%	3.81% - 4.63%
Expected volatility	117.0% - 127.2%	92.2% - 99.79%

Schedule of Changes in Fair Value of Warrant Liabilities

The table below provides a summary of the fair value of the Company’s warrant liability during the nine months ended September 30, 2024 (in thousands). As of September 30, 2023, the fair value of liability classified warrants was immaterial, and the change in the fair value of liability classified warrants during the three and nine months ended September 30, 2023 was immaterial.


	Three Months Ended September 30, 2024			Nine Months Ended September 30, 2024
Warrant liability
Beginning balance	$	6,160		$	—
Issuance of warrants		—			10,854
Change in fair value of warrants		(960	)		(5,654	)
Reclassification to equity		(5,200	)		(5,200	)
Ending balance	$	—		$	—

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023
Cash flows used in operating activities:
Net loss	$ (9,075)	$ (9,506)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	524	477
Amortization of deferred financing costs and debt discount	20	160
Share-based compensation expense	422	428
Accretion of discount on short-term investments	(70)
Non-cash financing expense	3,545
Change in fair value of warrants	(5,654)
Loss on disposal of property and equipment		2
Amortization of operating lease right-of-use assets	96	86
Stock issued for research and development		75
Increases (decreases) in cash caused by changes in operating assets and liabilities:
Grant receivable		(91)
Other current assets	704	3,190
Accounts payable and accrued expenses	1,326	(4,061)
Change in operating lease liabilities	(97)	(87)
Deferred grant liability	(1,084)	(1,643)
Net cash used in operating activities	(9,343)	(10,970)
Cash flows used in investing activities:
Purchases of property and equipment	(135)	(118)
Redemption of short-term investments	3,650
Purchase of short-term investments	(7,145)
Purchase of intangible assets	(545)
Net cash used in investing activities	(4,175)	(118)
Cash flows provided by financing activities:
Principal payments of term loan obligation	(3,996)	(1,206)
Proceeds from credit facility	3,292
Purchase of treasury stock	(374)
Proceeds from sale of common stock, net of offering costs of $0.2 million		5,180
Proceeds from sale of common stock, warrants and pre-funded warrants, net	7,265	0
Net cash provided by financing activities	6,187	3,974
Net decrease in cash and cash equivalents	(7,331)	(7,114)
Cash and cash equivalents at beginning of period	8,554	18,120
Cash and cash equivalents at end of period	1,223	11,006
Cash paid during period for:
Interest	32	186
Supplemental schedule of non-cash investing and financing activities:
Unpaid offering cost	$ 0	1
Right-of-use assets obtained in exchange for operating lease liability		71
Common stock issued in payment for in process research and development		$ 75

Stockholders' Deficit

9 Months Ended

Sep. 30, 2024

Stockholders Equity Note [Abstract]

Stockholders' Deficit

12. Stockholders’ Deficit

Preferred Stock

The Company has authorized 5,000,000 shares of preferred stock, par value $0.001 per share. The Company’s Board is authorized to designate the terms and conditions of any preferred stock the Company issues without further action by the common stockholders.

Series F Preferred Stock

On March 3, 2023, the Company filed a certificate of designation (the “Certificate of Designation”) with the Secretary of State of the State of Delaware, effective as of the time of filing, designating the rights, preferences, privileges and restrictions of the Series F Preferred Stock, with the total authorization of one (1) share of Series F Preferred Stock. The Certificate of Designation provided that the share of Series F Preferred Stock would have 50,000,000 votes per share of Series F Preferred Stock and would vote together with the Company’s common stock, as a single class exclusively with respect to any proposal to amend the Company’s certificate of incorporation to effect the reverse stock split. On March 3, 2023, the Company entered into a subscription and investment representation agreement with Richard J. Hawkins, chairman of the board of the Company, who is an accredited investor (the “Series F Preferred Stock Purchaser”), pursuant to which the Company agreed to issue and sell one (1) share of the Company’s Series F Preferred Stock, par value $0.001 per share, to the Series F Preferred Stock Purchaser for $1,000 in cash. The sale closed on March 3, 2023.

The outstanding share of Series F Preferred Stock was redeemed in whole, automatically effective upon the approval by the Company’s stockholders of the reverse stock split in April 2023. Upon such redemption, the Series F Preferred Stock Purchaser received consideration of $1,000 in cash.

On November 12, 2024, the Company filed a Certificate of Elimination (“Certificate of Elimination”) with the Secretary of State of the State of Delaware effecting the elimination of the Certificate of Designation relating to the Series F Preferred Stock. Following the filing of the Certificate of Elimination the previously-authorized share of the Series F Preferred Stock resumed the status of an undesignated share of the Company’s preferred stock.

Series B and C Preferred Stock

As of September 30, 2024, there were 938 outstanding shares of Series C Preferred Stock that can be converted into an aggregate of 27,792 shares of common stock, and 1,014 shares of Series B Convertible Preferred Stock that can be converted into an aggregate of 398 shares of common stock.

Common Stock

May 2024 Private Placement

On May 5, 2024, the Company entered into a securities purchase agreement (the “Securities Purchase Agreement”) with certain investors, including certain of the Company’s directors and executive officers (“Company Insiders”) (collectively, the “Purchasers”), for the sale and issuance by the Company of its securities (the “Initial Subscription”). On May 8, 2024, the Company entered into a first amendment to the Securities Purchase Agreement (together with the Securities Purchase Agreement, the “Purchase Agreement”), for the sale and issuance by the Company of additional securities to two of the Purchasers (the “Additional Subscription”, and together with the Initial Subscription, the “May 2024 Private Placement”). The Purchase Agreement provides for the sale and issuance by the Company of an aggregate of 3,591,532 shares (the “Private Placement Shares”) of the Company’s common stock or, at the election of each Purchaser, pre-funded warrants (the “Pre-Funded Warrants”), exercisable immediately at an exercise price of $0.001 per share, with each Private Placement Share or Pre-Funded Warrant accompanied by (i) a Series A common warrant (“Series A Warrants”) to purchase one share of common stock, for an aggregate of 3,591,532 Series A Warrants, and (ii) one Series B common warrant (“Series B Warrants”) to purchase one share of common stock, for an aggregate of 3,591,532 Series B Warrants.

The combined purchase price for each Private Placement Share and Pre-Funded Warrant from the Initial Subscription was $2.022, and $2.158 from the Additional Subscription, in each case together with one accompanying Series A Warrant and one accompanying Series B Warrant, provided, that the Company Insiders participated in the Initial Subscription at an offering price of $2.04 per Private Placement Share and accompanying Series A Warrant and Series B Warrant.

The exercise price of Series A Warrants and Series B Warrants from the Initial Subscription is $1.772 per share and $1.908 per share in the Additional Subscription, provided that the exercise price for the Series A Warrants and Series B Warrants issued to the Company Insiders is $1.79 per share. Subject to certain ownership limitations, the Series A Warrants will be exercisable until May 9, 2029, which is the five-year anniversary of issuance. Subject to certain ownership limitations, the Series B Warrants will be exercisable until June 24, 2025. The Pre-Funded Warrant will not expire until exercised in full.

Prior to the Amendment and Restatements (as defined below), if a holder of a Series A Warrant or a Series B Warrant was unable to exercise the warrant due to the limitation contained in the warrant that restricts the holder from owning above a specified beneficial ownership level (generally 4.99% or 9.99%) as the result of exercise of the warrant, then the holder had the right to elect upon exercise of the warrant to receive a Pre-Funded Warrant for the same number of shares of common stock that would otherwise have been received upon exercise of the warrant. In addition, prior to the Amendment and Restatements, the Series A Warrants and Series B Warrants provided for a call right starting June 24, 2025, in favor of the Company, if the volume-weighted average price of the shares of common stock exceeds specified prices.

The May 2024 Private Offering closed on May 9, 2024. The Company issued 2,151,544 Pre-Funded Warrants, 3,591,532 Series A Warrants and 3,591,532 Series B Warrants to purchase shares of its common stock in connection with the May 2024 Private Placement. The aggregate gross proceeds from the May 2024 Private Placement were approximately $7.3 million, before deducting $0.4 million of offering expenses.

The Company reviewed the terms of the Pre-Funded Warrants, Series A Warrants and Series B Warrants under the authoritative accounting guidance as of the issuance date.

As described above, the Series A Warrants and Series B Warrants were initially classified as liabilities for the reason that they could have been exercised into either shares of common stock or Pre-Funded Warrants at the holder’s option and thus failed the indexation guidance under ASC 815, Derivatives and Hedging. The Series A Warrant and Series B Warrant liability were initially recorded at fair value as of the issuance date, and under the terms of the Series A Warrants and Series B Warrants when issued that liability was subject to adjustment to estimated fair value at each balance sheet date until the warrants were settled. Refer below for additional information regarding the amendment of the Series A Warrants and Series B Warrants that eliminated the ability of the Series A Warrants and Series B Warrants to be exercised into Pre-Funded Warrants, and as a result, the reclassification of the Series A and B Warrants from liability to equity section of the condensed consolidated balance sheet.

The Pre-Funded Warrants are equity classified because they (1) are freestanding financial instruments that are legally detachable and separately exercisable from the common stock, (2) are immediately exercisable, (3) do not embody an obligation for the Company to repurchase its shares, (4) permit the holder to receive a fixed number of shares of common stock upon exercise, (5) are indexed to the Company’s common stock and (6) meet the equity classification criteria.

The proceeds from the May 2024 Private Placement were first allocated to the full fair value of the Series A Warrants and Series B Warrants due to the initial liability classification. As disclosed in Note 4, Fair Value Measurements, the fair value of the Series A Warrants and Series B Warrants at issuance was $10.9 million. Under authoritative guidance, if the fair value of a warrant liability exceeds the proceeds received in an arm’s length transaction with no rights or privileges that require separate accounting recognition as an asset identified, then the warrant liability is recorded at fair value with the excess of fair value over proceeds recognized as a loss in earnings. The Company recognized approximately $3.5 million in financing expense in the condensed consolidated statement of operations during the nine months ended September 30, 2024, which represents the excess of the fair value of the Series A Warrants and Series B Warrants at issuance over the proceeds. During the three and nine months ended September 30, 2024, the Company recognized a fair value gain on warrant liability of $1.0 and $5.7 million, respectively. Proceeds from the May 2024 Private Placement are shown as cash from financing transactions and the gain on warrant liability is included as an adjustment to reconcile the net loss to net cash used in operating activities in the statements of cash flows for the nine months ended September 30, 2024.

In addition, total offering expenses related to the May 2024 Private Placement of $0.4 million were recorded as a component of other expenses as the entire proceeds were allocated to the warrant liability, which, prior to the amendment described below, could be settled with either the Company’s shares of common stock or Pre-Funded Warrants, which are exercisable into the Company’s shares of common stock at any time at the holders’ option, but not in cash payment to the holders.

As of September 30, 2024, all of the Series A Warrants, and Series B Warrants issued in connection with the May 2024 Private Placement remained outstanding, and Pre-Funded Warrants to purchase 1,959,430 shares of the Company’s common stock remained outstanding.

Amendment and Restatement of Series A Warrants and Series B Warrants

On August 9, 2024, the Company amended and restated the Series A Warrants and Series B Warrants (the “Amendment and Restatements”) issued in the May 2024 Private Placement. The Amendment and Restatements eliminated the ability of the holders of the Series A Warrants and Series B Warrants to elect to purchase Pre-Funded Warrants upon exercise of the Series A Warrants and Series B Warrants in lieu of shares of common stock if the holder would have been restricted because of the specified beneficial ownership level in the Series A Warrants and Series B Warrants.

In addition, the Amendment and Restatements eliminated the Company’s call right under the terms of the Series A Warrants to call the Series A Warrants after June 24, 2025, if the volume-weighted average price of shares of common stock exceeded specified prices. There were no other changes in the terms of the Series A Warrants and Series B Warrants.

As a result of the Amendment and Restatements, the Series A Warrants and Series B Warrants, as amended, no longer fail the indexation guidance under ASC 815, Derivatives and Hedging, and the fair value of the warrant liability at the amendment date, in the amount of $5.2 million, was reclassified to equity.

Lincoln Park Purchase Agreement

On August 2, 2022, the Company entered into a purchase agreement (the “2022 Purchase Agreement”) and registration rights agreement pursuant to which Lincoln Park Capital Fund (“Lincoln Park”) committed to purchase up to $50.0 million of the Company’s common stock. Under the terms and subject to the conditions of the 2022 Purchase Agreement, the Company has the right, but not the obligation, to sell to Lincoln Park, and Lincoln Park is obligated to purchase up to $50.0 million of the Company’s common stock. Such sales of common stock by the Company are subject to certain limitations, and can occur from time to time, at the Company’s sole discretion, over the 36-month period commencing on August 17, 2022, subject to the satisfaction of certain conditions.

On May 16, 2022, the Company received stockholder approval for purposes of the Nasdaq listing rules to permit issuances of up to 57.5 million shares of the Company’s common stock (including the issuance of more than 19.99% of the Company’s common stock) to Lincoln Park, and it was pursuant to that approval that the Company entered into the 2022 Purchase Agreement.

Upon execution of the 2022 Purchase Agreement, the Company paid $0.1 million in cash as the initial commitment fee, and issued 32,846 shares as the initial commitment shares, to Lincoln Park as consideration for its irrevocable commitment to purchase shares of the Company’s common stock at its direction under the 2022 Purchase Agreement. The Company has agreed to pay an additional commitment fee, which it may elect to pay in cash or shares of its common stock, or a combination of cash and shares of its common stock, upon receipt of $25.0 million aggregate gross proceeds from sales of common stock to Lincoln Park under the 2022 Purchase Agreement.

On August 17, 2022, a registration statement (the “First Registration Statement”) was declared effective to cover the resale of up to 633,333 shares of the Company’s common stock comprised of (i) the 32,846 initial commitment shares, and (ii) up to 600,486 that the Company has reserved for issuance and sale to Lincoln Park under the 2022 Purchase Agreement from time to time from and after the date of the prospectus. The Company sold 527,166 shares of common stock to Lincoln Park in connection with the First Registration Statement.

On August 18, 2023, a second registration statement (the “Second Registration Statement”) was declared effective to cover the resale of up to an additional 1,500,000 shares of the Company’s common stock that the Company reserved for issuance and sale to Lincoln Park under the 2022 Purchase Agreement from time to time. The Company sold 150,000 shares of common stock to Lincoln Park in connection with the Second Registration Statement. The Company cannot sell more shares than registered under the Second Registration Statement under the 2022 Purchase Agreement without registering additional shares.

Actual sales of shares of common stock to Lincoln Park under the 2022 Purchase Agreement depend on a variety of factors to be determined by the Company from time to time, including, among others, market conditions, the trading price of the common stock and determinations by the Company as to the appropriate sources of funding for the Company and its operations. The net proceeds under the 2022 Purchase Agreement to the Company depend on the frequency and prices at which the Company sells shares of its common stock to Lincoln Park.

During the period from August 17, 2022 to December 31, 2022, the Company issued 266,666 shares of common stock under the 2022 Purchase Agreement for net proceeds of approximately $3.2 million. The Company issued 410,500 shares of common stock under the 2022 Purchase Agreement for net proceeds of approximately $1.0 million from January 1, 2023 to December 31, 2023. The Company did not issue any shares of common stock under the 2022 Purchase Agreement during the nine months ended September 30, 2024.

Share Repurchase Program and Treasury Stock

On October 31, 2023, the Company announced that its Board has approved a share repurchase program (the “Share Repurchase Program”), with authorization to repurchase up to $500,000 of the outstanding shares of the Company’s common stock. The Company funded repurchases under the Share Repurchase Program with available cash.

During the year ended December 31, 2023, the Company purchased 78,559 shares of its common stock for approximately $0.1 million as treasury stock. The Company purchased 179,866 shares of its common stock for approximately $0.4 million as treasury stock during the nine months ended September 30, 2024. As of September 30, 2024, no amount remained authorized for repurchase.

Loss per Share - Additional Information (Details)	Sep. 30, 2024 shares
May 2024 Private Placement [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Number of securities called by warrant or right	979,715

Stockholders' Deficit - Preferred Stock (Details)		9 Months Ended
Stockholders' Deficit - Preferred Stock (Details)	Mar. 03, 2023 USD ($) Votes $ / shares shares	Sep. 30, 2024 $ / shares shares	Dec. 31, 2023 $ / shares shares
Class of Stock [Line Items]
Preferred stock, shares authorized (in shares)		5,000,000	5,000,000
Preferred stock, par value (in dollars per share) \| $ / shares		$ 0.001	$ 0.001
Preferred stock, shares outstanding (in shares)		1,952	1,952
Common stock, par value (in dollars per share) \| $ / shares		$ 0.001	$ 0.001
Series B Convertible Preferred Stock [Member] \| 2018 Rights Offering [Member]
Class of Stock [Line Items]
Preferred stock, shares outstanding (in shares)		1,014
Number of preferred stock, shares converted		398
Series C Convertible Preferred Stock [Member] \| 2018 Rights Offering [Member]
Class of Stock [Line Items]
Preferred stock, shares outstanding (in shares)		938
Number of preferred stock, shares converted		27,792
Series F Convertible Preferred Stock [Member]
Class of Stock [Line Items]
Preferred stock, shares authorized (in shares)	1
Number Of Votes Per Share \| Votes	50,000,000
Consideration paid to preferred stock holders \| $	$ 1,000
Series F Convertible Preferred Stock [Member] \| Subscription Agreement [Member]
Class of Stock [Line Items]
Common stock, par value (in dollars per share) \| $ / shares	$ 0.001
Consideration to purchaser in cash \| $	$ 1,000
Issue and sale of share	1
Sale closed date	Mar. 03, 2023

Fair Value Measurements - Summary of Key Inputs Used in Valuation of Liability Classified Warrants (Details) - Warrant Liability [Member]	Sep. 30, 2024	May 05, 2024
Expected Term [Member] \| Minimum [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Warrant liability, Expected term	10 months 24 days	1 year 1 month 6 days
Expected Term [Member] \| Maximum [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Warrant liability, Expected term	4 years 8 months 12 days	5 years
Common Stock Market Price [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Warrant liability, Measurement input	1.45
Common Stock Market Price [Member] \| Minimum [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Warrant liability, Measurement input		2.01
Common Stock Market Price [Member] \| Maximum [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Warrant liability, Measurement input		2.27
Risk-free Interest Rate [Member] \| Minimum [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Warrant liability, Measurement input	3.81	4.5
Risk-free Interest Rate [Member] \| Maximum [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Warrant liability, Measurement input	4.63	5.1
Expected Volatility [Member] \| Minimum [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Warrant liability, Measurement input	92.2	117
Expected Volatility [Member] \| Maximum [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Warrant liability, Measurement input	99.79	127.2

Basis of Presentation and New Accounting Standards - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2024	Dec. 31, 2023
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001	$ 0.001
Common stock, shares issued (in shares)	6,154,758	6,154,758	4,522,656
Common stock, shares outstanding (in shares)	5,896,333	5,896,333	4,444,097
Preferred stock, shares authorized (in shares)	5,000,000	5,000,000	5,000,000
Maximum [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Unrealized gain on available-for-sale securities	$ 1,000	$ 1,000

Insider Trading Arrangements	3 Months Ended
Insider Trading Arrangements	Sep. 30, 2024
Trading Arrangements, by Individual
Rule 10b5-1 Arrangement Adopted	false
Non-Rule 10b5-1 Arrangement Adopted	false
Rule 10b5-1 Arrangement Terminated	false
Non-Rule 10b5-1 Arrangement Terminated	false

Stock-based Compensation - Stock Option Activity (Details)	9 Months Ended	12 Months Ended
	Sep. 30, 2024 USD ($) $ / shares shares	Dec. 31, 2023 $ / shares shares
Options [Roll Forward]
Balance as of December 31, 2023 (in shares) \| shares	140,109
Granted (in shares) \| shares	506,127
Cancelled/expired (in shares) \| shares	(47,696)
Balance as of September 30, 2024 (in shares) \| shares	598,540	140,109
Vested and expected to vest at September 30, 2024 (in shares) \| shares	540,286
Exercisable at September 30, 2024 (in shares) \| shares	110,674
Weighted Average Exercise Price [Roll Forward]
Balance as of December 31, 2023 (in dollars per share) \| $ / shares	$ 37.48
Granted (in dollars per share) \| $ / shares	1.58
Cancelled/expired (in dollars per share) \| $ / shares	38.02
Balance as of September 30, 2024 (in dollars per share) \| $ / shares	7.08	$ 37.48
Vested and expected to vest at September 30, 2024 (in dollars per share) \| $ / shares	28.73
Exercisable at September 30, 2024 (in dollars per share) \| $ / shares	$ 7.6
Weighted Average Remaining Contractual Life (years) [Roll Forward]
Balance as of September 30, 2024	9 years 3 months	8 years 25 days
Vested and expected to vest at September 30, 2024	7 years 4 months 13 days
Exercisable at September 30, 2024	9 years 2 months 12 days
Aggregated Intrinsic Value [Roll Forward]
Balance as of December 31, 2023 \| $	$ 64,000
Exercisable at September 30, 2024 \| $	$ 56,000

Loss per Share - Schedule of Computation of Basic and Diluted Net Loss Per Share of Common Stock (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2024	Jun. 30, 2024	Mar. 31, 2024	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Sep. 30, 2024	Sep. 30, 2023
Basic and diluted net loss per share of common stock calculation:
Net loss	$ (2,874)	$ (2,940)	$ (3,261)	$ (3,219)	$ (1,482)	$ (4,805)	$ (9,075)	$ (9,506)
Change in fair value of warrants							(5,047)
Net loss attributable to common stockholders - diluted	$ (2,874)			$ (3,219)			$ (14,122)	$ (9,506)
Weighted average shares of common stock outstanding - basic	7,855,763			3,225,351			6,232,123	2,688,232
Net loss per share of common stock - basic	$ (0.37)			$ (1)			$ (1.46)	$ (3.54)
Weighted average shares of common stock - diluted	7,855,763			3,225,351			8,452,338	2,688,232
Net loss per share of common stock - diluted	$ (0.37)			$ (1)			$ (1.67)	$ (3.54)

Stockholders' Deficit - Common stock (Details) - USD ($)						3 Months Ended					4 Months Ended	9 Months Ended		12 Months Ended	13 Months Ended	25 Months Ended
	Aug. 09, 2024	May 09, 2024	May 05, 2024	Aug. 02, 2022	May 16, 2022	Sep. 30, 2024	Jun. 30, 2024	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Dec. 31, 2022	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023	Sep. 30, 2024	Sep. 30, 2024	Oct. 31, 2023	Aug. 18, 2023	Aug. 17, 2022	Jul. 14, 2022
Class of Stock [Line Items]
Financing expense												$ 3,545,000
Common stock, shares authorized (in shares)						100,000,000						100,000,000		100,000,000	100,000,000	100,000,000
Proceeds from private placement		$ 7,300,000
Offering expenses													$ 200,000
Fair value loss on warrant liability						$ (960,000)						$ (5,654,000)
Remained authorized amount for repurchase						0						$ 0			$ 0	$ 0
Amendment and Restatements May 2024 Private Placement [Member] \| Series A Warrant and Series B Warrant [Member]
Class of Stock [Line Items]
Fair value of warrant liability reclassified to equity	$ 5,200,000
Common Stock [Member]
Class of Stock [Line Items]
Issue and sale of share							1,439,988	1,589,655	472,674	168,164
Number of stock repurchased												179,866		78,559
Treasury stock						400,000						$ 400,000		$ 100,000	$ 400,000	$ 400,000
Common Stock [Member] \| Amendment and Restatements May 2024 Private Placement [Member] \| Series A Warrant [Member]
Class of Stock [Line Items]
Restricted beneficial ownership level result of exercise of warrant to receive pre-funded warrant			4.99%
Common Stock [Member] \| Amendment and Restatements May 2024 Private Placement [Member] \| Series B Warrant [Member]
Class of Stock [Line Items]
Restricted beneficial ownership level result of exercise of warrant to receive pre-funded warrant			9.99%
Common Stock [Member] \| Maximum [Member]
Class of Stock [Line Items]
Authorized amount of repurchase of stock																	$ 500,000
2022 Purchase Agreement [Member] \| Lincoln Park Capital Fund, LLC [Member] \| Maximum [Member]
Class of Stock [Line Items]
Common stock, shares authorized (in shares)					57,500,000
2022 Purchase Agreement [Member] \| Lincoln Park Capital Fund, LLC [Member] \| Common Stock [Member]
Class of Stock [Line Items]
Maximum value of shares to be issued under agreement				$ 50,000,000
Issue and sale of share											266,666	0		410,500	150,000
Period exercisable from the date of issuance												36 months
Number of maximum common shares can be resale																			633,333
Initial commitment shares				32,846																32,846
Initial commitment fee paid in cash				$ 100,000
Aggregate gross proceeds from sales of common stock				$ 25,000,000
Proceeds from sale of common stock, net											$ 3,200,000			$ 1,000,000
2022 Purchase Agreement [Member] \| Lincoln Park Capital Fund, LLC [Member] \| Common Stock [Member] \| Minimum [Member]
Class of Stock [Line Items]
Percentage issuance of common stock					19.99%
2022 Purchase Agreement [Member] \| Lincoln Park Capital Fund, LLC [Member] \| Common Stock [Member] \| Maximum [Member]
Class of Stock [Line Items]
Number of maximum common shares can be resale																		1,500,000
Number of shares reserved for issuance and sale																			600,486
2020 Purchase Agreement [Member] \| Lincoln Park Capital Fund, LLC [Member] \| Common Stock [Member]
Class of Stock [Line Items]
Issue and sale of share																527,166
May 2024 Private Placement [Member]
Class of Stock [Line Items]
Financing expense			$ 3,500,000
Fair value loss on warrant liability						$ 1,000,000						$ 5,700,000
May 2024 Private Placement [Member] \| Common Stock [Member]
Class of Stock [Line Items]
Proceeds from issuance of warrants			$ 10,900,000
Proceeds from private placement		7,300,000
Offering expenses		$ 400,000
May 2024 Private Placement [Member] \| Common Stock [Member] \| Series A Warrant [Member]
Class of Stock [Line Items]
Number of shares issued		3,591,532	3,591,532
May 2024 Private Placement [Member] \| Common Stock [Member] \| Series A Warrant [Member] \| Initial Subscription [Member]
Class of Stock [Line Items]
Warrant exercise price (in dollars per share)			$ 1.772
May 2024 Private Placement [Member] \| Common Stock [Member] \| Series B Warrant [Member]
Class of Stock [Line Items]
Number of shares issued		3,591,532	3,591,532
May 2024 Private Placement [Member] \| Common Stock [Member] \| Series B Warrant [Member] \| Additional Subscription [Member]
Class of Stock [Line Items]
Warrant exercise price (in dollars per share)			$ 1.908
May 2024 Private Placement [Member] \| Common Stock [Member] \| Series A Warrant and Series B Warrant [Member]
Class of Stock [Line Items]
Warrant exercise price (in dollars per share)			1.79
May 2024 Private Placement [Member] \| Common Stock [Member] \| Series A Warrant and Series B Warrant [Member] \| Initial Subscription [Member]
Class of Stock [Line Items]
Offering price			2.04
May 2024 Private Placement [Member] \| Common Stock [Member] \| Pre-Funded Warrants [Member]
Class of Stock [Line Items]
Number of shares issued		2,151,544
Number of securities called by warrant or right						1,959,430						1,959,430			1,959,430	1,959,430
May 2024 Private Placement [Member] \| Common Stock [Member] \| Securities Purchase Agreement [Member]
Class of Stock [Line Items]
Warrant exercise price (in dollars per share)			$ 0.001
Issue and sale of share			3,591,532
May 2024 Private Placement [Member] \| Common Stock [Member] \| Private Placement and Pre-Funded Warrant [Member] \| Initial Subscription [Member]
Class of Stock [Line Items]
Purchase price of share			$ 2.022
May 2024 Private Placement [Member] \| Common Stock [Member] \| Private Placement and Pre-Funded Warrant [Member] \| Additional Subscription [Member]
Class of Stock [Line Items]
Purchase price of share			$ 2.158

Fair Value Measurements - Schedule of Changes in Fair Value of Warrant Liabilities (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2024
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning balance	$ 6,160	$ 0
Issuance of warrants	0	10,854
Change in fair value of warrants	(960)	(5,654)
Reclassification to equity	(5,200)	(5,200)
Ending Balance	$ 0	$ 0

CONDENSED CONSOLIDATED BALANCE SHEETS (UNAUDITED) (Parenthetical) - $ / shares	Sep. 30, 2024	Dec. 31, 2023
Stockholders' deficit:
Preferred stock, par value (in dollars per share)	$ 0.001	$ 0.001
Preferred stock, shares authorized (in shares)	5,000,000	5,000,000
Preferred stock, shares issued (in shares)	1,952	1,952
Preferred stock, shares outstanding (in shares)	1,952	1,952
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	100,000,000	100,000,000
Common stock, shares issued (in shares)	6,154,758	4,522,656
Common stock, shares outstanding (in shares)	5,896,333	4,444,097
Treasury stock, shares	258,425	78,559

Term Loan Obligations - Additional Information (Details) - Term Loan [Member] - USD ($) $ in Millions		9 Months Ended
	May 29, 2015	Sep. 30, 2024	Jun. 03, 2024
Debt Instrument [Line Items]
Origination date		May 29, 2015
Original loan amount	$ 17.7
Maturity date	May 01, 2021
Fees amount associated with loan			$ 3.3

Biocept Asset Acquisitions - Additional Information (Details) - Biocept Asset Acquisitions [Member]	Apr. 26, 2024 USD ($)
Asset Acquisition [Line Items]
Total cash payment	$ 400,000
Costs of acquisitions	$ 45,000

Document and Entity Information - shares	9 Months Ended
Document and Entity Information - shares	Sep. 30, 2024	Nov. 07, 2024
Cover [Abstract]
Entity Registrant Name	PLUS THERAPEUTICS, INC.
Entity Central Index Key	0001095981
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Emerging Growth Company	false
Entity Small Business	true
Entity Common Stock, Shares Outstanding		5,896,333
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	Q3
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2024
Document Quarterly Report	true
Document Transition Report	false
Entity Interactive Data Current	Yes
Entity Current Reporting Status	Yes
Entity Shell Company	false
Trading Symbol	PSTV
Title of 12(b) Security	Common Stock, par value $0.001
Security Exchange Name	NASDAQ
Entity File Number	001-34375
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	33-0827593
Entity Address, Address Line One	4200 Marathon Blvd
Entity Address, Address Line Two	Suite 200
Entity Address, City or Town	Austin
Entity Address, State or Province	TX
Entity Address, Postal Zip Code	78756
City Area Code	737
Local Phone Number	255-7194

Basis of Presentation and New Accounting Standards (Policies)	9 Months Ended
	Sep. 30, 2024
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Basis of Presentation and New Accounting Standards	The accompanying unaudited condensed consolidated financial statements for the three and nine months ended September 30, 2024 and 2023 have been prepared in accordance with accounting principles generally accepted in the United States of America for interim financial information. Accordingly, they do not include all of the information and footnotes required by accounting principles generally accepted in the United States of America for annual financial statements. The condensed balance sheet at December 31, 2023 has been derived from the audited financial statements at December 31, 2023, but does not include all of the information and footnotes required by accounting principles generally accepted in the United States of America for complete financial statements. On May 17, 2024, Plus Therapeutics, Inc. (the “Company”) established a wholly owned subsidiary, CNSide Diagnostics, LLC (“CNSide LLC”), a Delaware limited liability company. CNSide LLC was set up to operate the CNSide diagnostic portfolio, consisting of the intellectual property acquired by the Company from Biocept, Inc. (“Biocept”) in April 2024 (See Note 8, Biocept Asset Acquisitions, for further details). In the opinion of management, all adjustments (consisting of normal recurring adjustments) considered necessary for a fair presentation of the financial position and results of operations of the Company and its wholly owned subsidiary, CNSide LLC, have been included. Operating results for the three and nine months ended September 30, 2024 are not necessarily indicative of the results that may be expected for the remainder of the year ending December 31, 2024. These condensed consolidated financial statements should be read in conjunction with the financial statements and notes therein included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2023, filed with the Securities and Exchange Commission on March 5, 2024.
Grant Revenue Recognition	Grant Revenue Recognition In applying the provisions of Accounting Standards Codification (“ASC”) Topic 606, Revenue from Contracts with Customers (“ASC 606”), the Company has determined that government grants are out of the scope of ASC 606 because the funding entities do not meet the definition of a “customer”, as defined by ASC 606, as the Company does not consider there to be a transfer of control of goods or services. With respect to each grant, the Company determines if it has a collaboration in accordance with ASC Topic 808, Collaborative Arrangements (“ASC 808”). For grants outside the scope of ASC 808, the Company applies International Accounting Standards No. 20, Accounting for Government Grants and Disclosure of Government Assistance, by analogy, and revenue is recognized when the Company incurs expenses related to the grant for the amount the Company is entitled to under the provisions of the contract. The Company also considers the guidance in ASC Topic 730, Research and Development, which requires an assessment, at the inception of each grant, of whether each grant agreement is a liability. If the Company is obligated to repay funds received regardless of the outcome of the related research and development activities, then the Company is required to estimate and recognize that liability. Alternatively, if the Company is not required to repay the funds, then payments received are recorded as revenue or contra-expense as the expenses are incurred. Deferred grant liability represents grant funds received or receivable for which the allowable expenses have not yet been incurred as of the balance sheet date.
Warrants	Warrants Warrants are accounted for as either derivative liabilities or as equity instruments depending on the specific terms of the agreement in accordance with applicable accounting guidance provided in ASC Topic 815 - Derivatives and Hedging. Equity-classified instruments are recorded in additional paid-in capital at issuance and are not subject to remeasurement. Liability-classified warrants are recorded at fair value at each reporting period with any change in fair value recognized as a component of change in fair value of warrants in the condensed consolidated statements of operations. The Company periodically evaluates changes in facts and circumstances that could impact the classification of warrants.
Available-for-Sale Securities	Available-for-Sale Securities The Company’s available-for-sale securities consist of U.S. government and agency securities. Securities with maturities from the date of purchase of less than three months are included in cash equivalents. The Company classifies its marketable securities as available-for-sale and records such assets at estimated fair value in the condensed consolidated balance sheets, with unrealized gains and losses, if any, reported as a component of other comprehensive income (loss) within the condensed consolidated statements of operations and comprehensive income/loss and as a separate component of stockholders’ equity. Realized gains and losses are calculated on the specific identification method and recorded as interest income (loss). At each balance sheet date, the Company assesses available-for-sale securities in an unrealized loss position to determine whether the decline in fair value below amortized cost is a result of credit losses or other factors, whether the Company expects to recover the amortized cost of the security, the Company’s intent to sell and if it is more likely than not that the Company will be required to sell the securities before the recovery of amortized cost. The Company records changes in allowance for expected credit loss in other income (expense). There has been no allowance for expected credit losses recorded during any of the periods presented. Any premium arising at purchase is amortized to the earliest call date and any discount arising at purchase is accreted to maturity. Accretion of discounts are recorded in interest income in the condensed consolidated statements of operations and comprehensive income/loss. During the three and nine months ended September 30, 2024, the unrealized gain on the Company’s available-for-sale securities was less than $1,000, and not presented separately in the condensed consolidated statement of operations.
Recently Issued Accounting Pronouncements	Recently Issued Accounting Pronouncements In December 2023, the Financial Accounting Standards Board (the “FASB”) issued Accounting Standards Update (ASU) No. 2023-09 Income Taxes (Topic 740): Improvements to Income Tax Disclosure. This ASU includes amendments that further enhance income tax disclosures, primarily through standardization and disaggregation of rate reconciliation categories and income taxes paid by jurisdiction. The ASU is effective for years beginning after December 15, 2024, but early adoption is permitted. This ASU should be applied on a prospective basis, although retrospective application is permitted. Management is currently evaluating the impact of the changes required by the new standard on the Company’s consolidated financial statements and related disclosures. In November 2023, the FASB issued Accounting Standard Update (ASU) No. 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures. The new standard is intended to improve annual and interim reportable segment disclosure requirements regardless of number of reporting units, primarily through enhanced disclosures of significant expenses. The amendment requires public entities to disclose significant segment expenses that are regularly provided to the CODM and included within each reported measure of segment profit and loss. This update is effective for fiscal years beginning after December 15, 2023, and interim periods within those fiscal years starting after December 15, 2024. This ASU must be applied retrospectively to all prior periods presented. Management is currently evaluating the impact of the changes required by the new standard on the Company’s consolidated financial statements and related disclosures.
Use of Estimates	Use of EstimatesThe preparation of consolidated financial statements in conformity with U.S. generally accepted accounting principles requires management to make estimates and assumptions affecting the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the consolidated financial statements, and the reported amounts of revenue and expenses during the reporting period. The Company’s most significant estimates and critical accounting policies involve reviewing assets for impairment and determining the assumptions used in measuring stock-based compensation expense and warrant liability.

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED) (Parenthetical) $ in Millions	9 Months Ended
	Sep. 30, 2023 USD ($)
Statement Of Cash Flows [Abstract]
Offering cost	$ 0.2

Line of Credit Facility - Additional Information (Details) - Pershing Credit Facility [Member] - USD ($) $ in Millions	May 31, 2024	Sep. 30, 2024
Line of Credit Facility [Line Items]
Line of credit	$ 3.3
Percentage of credit facility cannot exceed collateralized marketable securities	91.50%
Collateralized marketable securities		$ 3.6
Debt instrument floor rate	5.50%
Basis variable rate	1.75%
Applicable fees	0.50%
Prime Rate [Member]
Line of Credit Facility [Line Items]
Basis variable rate	3.00%

CONDENSED CONSOLIDATED BALANCE SHEETS (UNAUDITED) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Current assets:
Cash and cash equivalents	$ 1,223	$ 8,554
Investments	3,565
Other current assets	576	1,280
Total current assets	5,364	9,834
Property and equipment, net	591	906
Operating lease right-of-use assets	106	202
Goodwill	372	372
Intangible assets, net	513	42
Other assets	32	32
Total assets	6,978	11,388
Current liabilities:
Accounts payable and accrued expenses	7,912	6,631
Operating lease liability	68	120
Deferred grant liability	840
Line of credit	3,292
Term loan obligation, current		3,976
Total current liabilities	12,112	10,727
Noncurrent operating lease liability	40	85
Deferred grant liability		1,924
Total liabilities	12,152	12,736
Commitments and contingencies (Note 10)
Stockholders' deficit:
Preferred stock, $0.001 par value; 5,000,000 shares authorized; 1,952 shares issued and outstanding at September 30, 2024 and December 31, 2023, respectively
Common stock, $0.001 par value; 100,000,000 shares authorized; 6,154,758 and 5,896,333 issued and outstanding at September 30, 2024, and 4,522,656 issued and 4,444,097 outstanding as of December 31, 2023, respectively	6	5
Treasury stock (at cost, 258,425 and 78,559 shares as of September 30, 2024 and December 31, 2023, respectively)	(500)	(126)
Additional paid-in capital	484,896	479,274
Accumulated deficit	(489,576)	(480,501)
Total stockholders' deficit	(5,174)	(1,348)
Total liabilities and stockholders' deficit	$ 6,978	$ 11,388

Stock-based Compensation - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2024	Jun. 06, 2024
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock shares to be issued (in shares)		506,127
Stock option contractual term		10 years
Stock option vesting percentage		25.00%
Total unamortized compensation cost related to outstanding unvested stock options and restricted stock awards	$ 0.8	$ 0.8
Weighted average period for recognition of cost		2 years 9 months 18 days
Minimum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock option vesting period		2 years
Maximum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock option vesting period		4 years
2015 Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Securities remaining and available for future issuances (in shares)	62,908	62,908	75,000
2020 Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Securities remaining and available for future issuances (in shares)	692,596	692,596
Common stock shares to be issued (in shares)	1,000,000	1,236,667

Grant Revenue - Additional Information (Details) - USD ($)		3 Months Ended		9 Months Ended
	Sep. 19, 2022	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Oct. 04, 2024	Sep. 01, 2024
Grant [Member]
Disaggregation of Revenue [Line Items]
Revenue recognized		$ 1,456,000	$ 1,240,000	$ 4,412,000	$ 3,600,000
CPRIT Contract [Member]
Disaggregation of Revenue [Line Items]
Grant funding term	3 years
CPRIT grant funding term, description				The CPRIT Grant is subject to customary CPRIT funding conditions, including, but not limited to, a matching fund requirement (one dollar for every two dollars awarded by CPRIT), revenue sharing obligations upon commercialization of rhenium (186Re) obisbemeda based on specific dollar thresholds and tiered low single digit royalty rates until CPRIT receives the aggregate amount of 400% of the proceeds awarded under the CPRIT Grant, and certain reporting requirements.
Contract effective date	Aug. 31, 2022
Contract termination date	Aug. 30, 2025
Percentage of aggregate amount of proceeds awarded under CPRIT grant	400.00%
Percentage of grant proceeds with interest not exceed annually	5.00%
CPRIT Contract [Member] \| Grant [Member]
Disaggregation of Revenue [Line Items]
Revenue recognized		$ 1,500,000	$ 4,400,000	$ 1,200,000	$ 3,600,000
Department of Defense Award [Member]
Disaggregation of Revenue [Line Items]
Research and development award period							3 years
Grant revenue				$ 0
Department of Defense Award [Member] \| Subsequent Event
Disaggregation of Revenue [Line Items]
First payment received						$ 900,000
Congressionally Directed Medical Research Programs [Member]
Disaggregation of Revenue [Line Items]
Amount to be received as award for research and development							$ 3,000,000

Commitments and Contingencies - Additional Information (Details) - USD ($)	9 Months Ended
	Sep. 30, 2024	Dec. 31, 2023	Jul. 01, 2023	Mar. 31, 2023
Recorded Unconditional Purchase Obligation [Line Items]
Operating leases expiry year	2025
Operating lease right-of-use assets	$ 106,000	$ 202,000
Pre-clinical Research Study Obligations [Member]
Recorded Unconditional Purchase Obligation [Line Items]
Contractual obligation	$ 0
Charlottesville [Member]
Recorded Unconditional Purchase Obligation [Line Items]
Lessee, operating lease, term of contract	12 months
Lessee, operating lease, existence of option to extend [true false]	true
Lessee, operating lease, option to extend	The Charlottesville Lease has a term of 12 months and the Company has the ability to renew for three additional one-year periods.
Lessee, operating lease, renewal term	1 year
Lease liability				$ 80,000
Operating lease discount rate			13.47%	12.76%
Operating lease right-of-use assets			$ 19,000

License Agreements - Additional Information (Details) - USD ($)		3 Months Ended		9 Months Ended
	Mar. 29, 2020	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023	Sep. 07, 2023
Research and development expense		$ 2,858,000	$ 2,493,000	$ 8,394,000	$ 6,896,000
Voting stock, value		6,000		6,000		$ 5,000
Biocept Agreement [Member] \| Common Stock [Member]
Shares issued							53,381
Research and development expense				75,000
Nano Tx Licenses Agreement [Member]
License fee payment in cash	$ 400,000
Voting stock, value	$ 300,000
Percentage of non-dilutive monetary awards required to pay	15.00%
Accrued payments due to NanoTx		$ 1,000,000		$ 1,000,000

Pay vs Performance Disclosure - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
Pay vs Performance Disclosure - USD ($) $ in Thousands	Sep. 30, 2024	Jun. 30, 2024	Mar. 31, 2024	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Sep. 30, 2024	Sep. 30, 2023
Pay vs Performance Disclosure
Net Income (Loss)	$ (2,874)	$ (2,940)	$ (3,261)	$ (3,219)	$ (1,482)	$ (4,805)	$ (9,075)	$ (9,506)

Fair Value Measurements - Summary of Financial Assets Measured at Fair Value on Recurring Basis (Details) - Recurring Basis [Member] - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	$ 4,761
Money Market [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	1,196	$ 5,449
Treasury Bills and Government Agency Bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	3,565
Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	1,196
Level 1 [Member] \| Money Market [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	1,196	$ 5,449
Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	3,565
Level 2 [Member] \| Treasury Bills and Government Agency Bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	$ 3,565

CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' DEFICIT (UNAUDITED) - USD ($) $ in Thousands	Total	Series F Preferred Stock [Member]	Convertible Preferred Stock [Member]	Preferred Stock [Member]	Preferred Stock [Member] Series F Preferred Stock [Member]	Common Stock [Member]	Treasury Stock [Member]	Additional Paid-in Capital [Member]	Additional Paid-in Capital [Member] Series F Preferred Stock [Member]	Accumulated Deficit [Member]
Balance at Dec. 31, 2022	$ 6,445					$ 2		$ 473,628		$ (467,185)
Balance (in shares) at Dec. 31, 2022			1,952			2,240,092
Stock-based compensation	140							140
Sale and issuance of common stock, net	895	$ 1						895	$ 1
Sale and issuance of common stock, net (in shares)					1	168,164
Net loss	(4,805)									(4,805)
Balance at Mar. 31, 2023	2,676					$ 2		474,664		(471,990)
Balance (in shares) at Mar. 31, 2023			1,952	1		2,408,256
Balance at Dec. 31, 2022	6,445					$ 2		473,628		(467,185)
Balance (in shares) at Dec. 31, 2022			1,952			2,240,092
Net loss	(9,506)
Balance at Sep. 30, 2023	2,622					$ 6		479,308		(476,691)
Balance (in shares) at Sep. 30, 2023			1,952			4,522,656
Balance at Dec. 31, 2022	6,445					$ 2		473,628		(467,185)
Balance (in shares) at Dec. 31, 2022			1,952			2,240,092
Balance at Dec. 31, 2023	(1,348)					$ 5	$ (126)	479,274		(480,501)
Balance (in shares) at Dec. 31, 2023			1,952			4,522,656	(78,559)
Balance at Mar. 31, 2023	2,676					$ 2		474,664		(471,990)
Balance (in shares) at Mar. 31, 2023			1,952	1		2,408,256
Redemption of Series F preferred stock (in shares)					(1)
Stock-based compensation	140							140
Sale and issuance of common stock, net	1,328					$ 1		1,327
Sale and issuance of common stock, net (in shares)						472,674
Fractional adjustment						(1,310)
Net loss	(1,482)									(1,482)
Balance at Jun. 30, 2023	2,662					$ 3		476,131		(473,472)
Balance (in shares) at Jun. 30, 2023			1,952			2,879,620
Stock-based compensation	148							148
Sale and issuance of common stock, net	2,956					$ 2		2,954
Sale and issuance of common stock, net (in shares)						1,589,655
Issuance of common stock for in process research and development (in shares)						53,381
Issuance of common stock for in process research and development	75							75
Net loss	(3,219)									(3,219)
Balance at Sep. 30, 2023	2,622					$ 6		479,308		(476,691)
Balance (in shares) at Sep. 30, 2023			1,952			4,522,656
Balance at Dec. 31, 2023	(1,348)					$ 5	$ (126)	479,274		(480,501)
Balance (in shares) at Dec. 31, 2023			1,952			4,522,656	(78,559)
Stock-based compensation	146							146
Purchase of treasury stock	(374)						$ (374)
Purchase of treasury stock (in Shares)							(179,866)
Net loss	(3,261)									(3,261)
Balance at Mar. 31, 2024	(4,837)					$ 5	$ (500)	479,420		(483,762)
Balance (in shares) at Mar. 31, 2024			1,952			4,522,656	(258,425)
Balance at Dec. 31, 2023	(1,348)					$ 5	$ (126)	479,274		(480,501)
Balance (in shares) at Dec. 31, 2023			1,952			4,522,656	(78,559)
Net loss	(9,075)
Balance at Sep. 30, 2024	(5,174)					$ 6	$ (500)	484,896		(489,576)
Balance (in shares) at Sep. 30, 2024			1,952			6,154,758	(258,425)
Balance at Mar. 31, 2024	(4,837)					$ 5	$ (500)	479,420		(483,762)
Balance (in shares) at Mar. 31, 2024			1,952			4,522,656	(258,425)
Stock-based compensation	151							151
Sale and issuance of common stock, net	1					$ 1
Sale and issuance of common stock, net (in shares)						1,439,988
Net loss	(2,940)									(2,940)
Balance at Jun. 30, 2024	(7,625)					$ 6	$ (500)	479,571		(486,702)
Balance (in shares) at Jun. 30, 2024			1,952			5,962,644	(258,425)
Stock-based compensation	125							125
Reclass of warrants to equity	5,200							5,200
Exercise of pre-funded warrants (in Shares)						192,114
Net loss	(2,874)									(2,874)
Balance at Sep. 30, 2024	$ (5,174)					$ 6	$ (500)	$ 484,896		$ (489,576)
Balance (in shares) at Sep. 30, 2024			1,952			6,154,758	(258,425)