MediciNova (MNOV) 10-K 16 Feb 23 2022 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2022	Feb. 13, 2023	Jun. 30, 2022
Cover [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2022
Document Fiscal Year Focus	2022
Document Fiscal Period Focus	FY
Trading Symbol	MNOV
Entity Registrant Name	MEDICINOVA, INC.
Entity Central Index Key	0001226616
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	No
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		49,046,246
Entity Public Float			$ 117,554,962
Entity File Number	001-33185
Entity Tax Identification Number	33-0927979
Entity Address, Address Line One	4275 Executive Square
Entity Address, Address Line Two	Suite 300
Entity Address, City or Town	La Jolla
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	92037
City Area Code	858
Local Phone Number	373-1500
Document Annual Report	true
Document Transition Report	false
Entity Incorporation, State or Country Code	DE
Entity Interactive Data Current	Yes
Title of 12(b) Security	Common Stock, par value $0.001 per share
Security Exchange Name	NASDAQ
ICFR Auditor Attestation Flag	false
Auditor Name	BDO USA, LLP
Auditor Firm ID	243
Auditor Location	San Diego, California
Documents Incorporated by Reference	Portions of the registrant’s Proxy Statement to be filed with the Securities and Exchange Commission pursuant to Regulation 14A in connection with the registrant’s 2023 Annual Meeting of Stockholders, which will be filed subsequent to the date hereof, are incorporated by reference into Part III of this Form 10-K.

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($)	Dec. 31, 2022	Dec. 31, 2021
Current assets:
Cash and cash equivalents	$ 18,505,493	$ 71,430,954
Prepaid expenses and other current assets	499,403	577,992
Investments	39,982,213
Total current assets	58,987,109	72,008,946
Goodwill	9,600,240	9,600,240
In-process research and development	4,800,000	4,800,000
Property and equipment, net	45,269	57,565
Right-of-use asset	629,495	824,215
Other non-current assets	92,792	115,492
Total assets	74,154,905	87,406,458
Current liabilities:
Accounts payable	424,646	402,740
Accrued liabilities and other current liabilities	2,605,308	2,298,203
Operating lease liability	157,505	131,965
Total current liabilities	3,187,459	2,832,908
Deferred tax liability	201,792	201,792
Other non-current liabilities	523,619	694,674
Total liabilities	3,912,870	3,729,374
Commitments and contingencies (Note 5)
Stockholders’ equity:
Common stock, $0.001 par value; 100,000,000 shares authorized at December 31, 2022 and December 31, 2021; 49,046,246 and 49,043,246 shares issued and outstanding at December 31, 2022 and December 31,2021, respectively	49,046	49,043
Additional paid-in capital	477,438,451	476,788,012
Accumulated other comprehensive loss	(115,285)	(98,877)
Accumulated deficit	(407,130,177)	(393,061,094)
Total stockholders’ equity	70,242,035	83,677,084
Total liabilities and stockholders’ equity	$ 74,154,905	$ 87,406,458

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2022	Dec. 31, 2021
Statement of Financial Position [Abstract]
Common stock, par value	$ 0.001	$ 0.001
Common stock, shares authorized	100,000,000	100,000,000
Common stock, shares issued	49,046,246	49,043,246
Common stock, shares outstanding	49,046,246	49,043,246

Consolidated Statements of Oper

Consolidated Statements of Operations and Comprehensive Loss - USD ($)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Income Statement [Abstract]
Revenues		$ 4,037,500
Operating expenses:
Research, development and patents	$ 9,143,792	8,538,027
General and administrative	5,484,857	5,715,285
Total operating expenses	14,628,649	14,253,312
Operating loss	(14,628,649)	(10,215,812)
Interest income	809,673	143,626
Other expense, net	(247,285)	(59,498)
Loss before income taxes	(14,066,261)	(10,131,684)
Income tax expense	(2,822)	(2,568)
Net loss applicable to common stockholders	$ (14,069,083)	$ (10,134,252)
Basic net loss per common share	$ (0.29)	$ (0.21)
Diluted net loss per common share	$ (0.29)	$ (0.21)
Shares used to compute basic net loss per common share	49,045,342	48,596,255
Shares used to compute diluted net loss per common share	49,045,342	48,596,255
Net loss applicable to common stockholders	$ (14,069,083)	$ (10,134,252)
Other comprehensive loss, net of tax:
Foreign currency translation adjustments	(16,408)	(10,658)
Comprehensive loss	$ (14,085,491)	$ (10,144,910)

Consolidated Statements of Stoc

Consolidated Statements of Stockholders' Equity - USD ($)	Total	Common stock	Additional paid-in capital	Accumulated other comprehensive loss	Accumulated deficit
Balance at Dec. 31, 2020	$ 71,326,500	$ 45,025	$ 454,296,536	$ (88,219)	$ (382,926,842)
Balance, shares at Dec. 31, 2020		45,024,560
Share-based compensation	1,717,513		1,717,513
Issuance of shares under an employee stock purchase plan (ESPP)	$ 6,110	$ 2	6,108
Issuance of shares under an employee stock purchase plan (ESPP), shares	1,424	1,424
Issuance of common stock in a private placement transaction, net of issuance costs	$ 19,881,632	$ 3,656	19,877,976
Issuance of common stock in a private placement transaction, net of issuance costs, shares		3,656,307
Issuance of common stock for option exercises	$ 890,239	$ 360	889,879
Issuance of common stock for option exercises, shares	360,955	360,955
Net loss	$ (10,134,252)				(10,134,252)
Foreign currency translation adjustments	(10,658)			(10,658)
Balance at Dec. 31, 2021	83,677,084	$ 49,043	476,788,012	(98,877)	(393,061,094)
Balance, shares at Dec. 31, 2021		49,043,246
Share-based compensation	642,522		642,522
Issuance of common stock for option exercises	$ 7,920	$ 3	7,917
Issuance of common stock for option exercises, shares	3,000	3,000
Net loss	$ (14,069,083)				(14,069,083)
Foreign currency translation adjustments	(16,408)			(16,408)
Balance at Dec. 31, 2022	$ 70,242,035	$ 49,046	$ 477,438,451	$ (115,285)	$ (407,130,177)
Balance, shares at Dec. 31, 2022		49,046,246

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Operating activities:
Net loss	$ (14,069,083)	$ (10,134,252)
Adjustments to reconcile net loss to net cash used in operating activities:
Non-cash stock-based compensation	642,522	1,717,513
Depreciation and amortization	17,707	26,149
Non-cash interest on investments	(154,003)
Loss on disposal of investments	122,475
Loss on disposal of property and equipment		286
Change in carrying amount of right-of-use asset	194,719	216,640
Changes in assets and liabilities:
Prepaid expenses and other assets	150,605	50,319
Accounts payable, accrued liabilities and other liabilities	329,010	(1,026,525)
Operating lease liabilities	(145,515)	(231,735)
Net cash used in operating activities	(12,911,563)	(9,381,605)
Investing activities:
Purchases of investments	(59,877,526)
Proceeds from disposal of investments	19,877,526
Acquisitions of property and equipment	(5,010)	(28,732)
Net cash used in investing activities	(40,005,010)	(28,732)
Financing activities:
Proceeds from issuance of common stock and exercise of common stock options	7,920	20,890,239
Common stock issuance costs		(118,368)
Proceeds from issuance of equity under ESPP		6,110
Net cash provided by financing activities	7,920	20,777,981
Effect of exchange rate changes on cash and cash equivalents	(16,808)	26,547
Net change in cash and cash equivalents	(52,925,461)	11,394,191
Cash and cash equivalents, beginning of year	71,430,954	60,036,763
Cash and cash equivalents, end of year	$ 18,505,493	71,430,954
Supplemental disclosure of cash flow information:
Right-of-use asset obtained in exchange for operating lease liability		$ 870,373

Organization and Summary of Sig

Organization and Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2022
Accounting Policies [Abstract]
Organization and Summary of Significant Accounting Policies	1. Organization and Summary of Significant Accounting Policies Organization and Business MediciNova, Inc. (the “Company” or “MediciNova”) was incorporated in the state of Delaware in September 2000 and is a public company. The Company’s common stock is listed in both the United States and Japan and trades on the NASDAQ Global Market and the Standard Market of the Tokyo Stock Exchange. The Company is a biopharmaceutical company focused on developing novel therapeutics for the treatment of serious diseases with unmet medical needs with a commercial focus on the United States market. The Company’s current strategy is to focus its development activities on MN-166 (ibudilast) for neurological and other disorders such as progressive multiple sclerosis (MS), amyotrophic lateral sclerosis (ALS), chemotherapy-induced peripheral neuropathy, degenerative cervical myelopathy, glioblastoma, substance dependence and addiction (e.g., methamphetamine dependence, opioid dependence, and alcohol dependence), and prevention of acute respiratory distress syndrome, and MN-001 (tipelukast) for fibrotic and other diseases such as nonalcoholic fatty liver disease (NAFLD) and idiopathic pulmonary fibrosis (IPF). The Company’s pipeline also includes MN-221 (bedoradrine) for the treatment of acute exacerbation of asthma, and MN-029 (denibulin) for solid tumor cancers. Principles of Consolidation The consolidated financial statements include the accounts of MediciNova, Inc. and its wholly owned subsidiaries MediciNova Japan, Inc., MediciNova (Europe) Limited, MediciNova Europe GmbH and Avigen Inc. The financial statements of the Company’s foreign subsidiaries are measured using their local currency as the functional currency. The resulting translation adjustments are recorded as a component of other comprehensive income or loss. Intercompany transaction gains or losses at each period end are included as translation adjustments and recorded within other comprehensive income or loss. All intercompany transactions and balances are eliminated in consolidation. Segment Reporting Operating segments are identified as components of an enterprise about which separate discrete financial information is available for evaluation by the chief operating decision-maker in making decisions regarding resource allocation and assessing performance. The Company operates in a single operating segment – the acquisition and development of small molecule therapeutics for the treatment of serious diseases with unmet medical needs. Impact of COVID-19 on the Company’s Business The pandemic caused by an outbreak of a new strain of coronavirus (“COVID-19” or “the pandemic”) has resulted, and is likely to continue to result, in significant national and global economic disruption and may adversely affect the Company’s business. So far, the Company has experienced certain adverse effects on its business as well as been provided certain opportunities as a result of the pandemic. The pandemic caused a decrease in the number of patient visits at some clinical trial sites which the Company believes resulted in slower enrollment in the Company's clinical trials than would have occurred without the pandemic. However, the Company has seen an increase in the number of patient visits compared to earlier in the pandemic and the Company continues to enroll patients in clinical trials. Throughout the pandemic, the Company has continued with routine clinical trial activities including executing new clinical trial agreements, negotiating budgets, institutional review board (IRB) approvals, site training, and other activities related to the initiation of new clinical trials and the opening of new clinical trial sites, although some of these activities took longer to complete than what the Company experienced prior to the pandemic. The pandemic created certain new opportunities for the Company's clinical development and the Company has pursued those opportunities. Following the outbreak of the pandemic, the Company designed a clinical trial to evaluate MN-166 (ibudilast) for prevention of acute respiratory distress syndrome (ARDS) caused by COVID-19. The Company continues to actively monitor the pandemic situation and the possible effects on its financial condition, liquidity, operations, suppliers, industry, and workforce. Use of Estimates The preparation of the consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. Cash and Cash Equivalents Cash and cash equivalents consist of cash and other highly liquid investments, including money market accounts, with original maturities of three months or less from the date of purchase. Investments Investments purchased with an original maturity of greater than three months are classified as investments. Investments are stated at fair value and are classified as current or non-current based on the nature of the securities as well as their stated maturities. As of December 31, 2022 , investments consisted of bank certificates of deposit with original purchased maturity dates between seven and 13 months . Concentrations and Credit Risk The Company maintains cash balances and has purchased certificates of deposit at various financial institutions and such balances and certificates of deposit commonly exceed the $ 250,000 amount insured by the Federal Deposit Insurance Corporation. The Company also maintains money market funds at various financial institutions which are not federally insured although are invested primarily in U.S. government securities. The Company has not experienced any losses in such accounts and management believes that the Company does not have significant credit risk with respect to such cash and cash equivalents. Fair Value of Financial Instruments Financial instruments, including cash equivalents and accounts payable, are carried at cost, which management believes approximates fair value because of the short-term nature of these instruments. IPR&D, Long-Lived Assets and Goodwill Amounts incurred related to in-process research and development (“IPR&D”) or asset purchases of IPR&D are expensed as incurred. Amounts allocated to IPR&D in connection with a business combination are recorded at fair value and are considered indefinite-lived intangible assets until completion or abandonment of the associated research and development efforts. If and when development is complete, which generally occurs when regulatory approval to market a product is obtained, the associated assets are deemed finite-lived and amortized over a period that best reflects the economic benefits provided by these assets. During the period the assets are considered indefinite-lived, they will not be amortized but will be tested annually for impairment or more frequently if indicators of impairment exist. The Company first assesses qualitative factors to determine whether it is more likely than not that the fair value of the IPR&D is less than its carrying amount as a basis for determining whether it is necessary to perform a quantitative assessment. If, after assessing qualitative factors, the Company determines it is not more likely than not that the fair value is less than its carrying amount, then a quantitative assessment is unnecessary. If the quantitative assessment is deemed necessary, the excess of the carrying value over fair value will be recorded as an impairment. The qualitative assessment focuses on the key inputs, assumptions and rationale utilized in the establishment of the carrying value and related changes since the last quantitative assessment. Based on the results of the Company’s annual qualitative assessment, the Company concluded that it is not more likely than not that IPR&D was impaired for any of the periods presented. The Company’s long-lived assets are reviewed for impairment whenever events or changes in circumstances indicate that the carrying value of an asset (or asset group) may not be recoverable, and the Company will perform an impairment analysis. Long-lived assets are deemed to be impaired when the undiscounted cash flows expected to be generated by the asset (or asset group) are less than the asset’s carrying amount. Any required impairment loss would be measured as the amount by which the asset’s (or asset group’s) carrying value exceeds its fair value and would be recorded as a reduction in the carrying value of the related asset and a charge to operating expense. There were no events or changes in circumstances to indicate that the carrying value of an asset (or asset group) may not be recoverable for any of the periods presented. Goodwill is reviewed for impairment annually (as of December 31st) or more frequently if indicators of impairment exist. As the Company operates in a single operating segment and reporting unit, goodwill is assessed at a consolidated level. The Company first assesses qualitative factors to determine whether it is more likely than not that the fair value of the reporting unit is less than its carrying amount, including goodwill. If so, the Company will proceed with a quantitative assessment that compares the fair value of the reporting unit with its carrying amount. If the fair value exceeds the carrying value as a result of either the qualitative or quantitative test, goodwill is not considered impaired. The qualitative factors include economic environment, business climate, market capitalization, operating performance, competition, and other factors. The Company placed the highest weight in excess cushion of the market capitalization to the equity carrying value in the analysis. Based on the results of the Company’s annual qualitative assessment, the Company concluded that it is not more likely than not that goodwill was impaired for any of the periods presented. Research, Development and Patents Research and development costs are expensed in the period incurred. Research and development costs primarily consist of salaries and related expenses for personnel, facilities and depreciation, research and development supplies, licenses and outside services. Such research and development costs totaled $ 8.7 million and $ 8.1 million for the years ended December 31, 2022 and 2021, respectively. Costs related to filing and pursuing patent applications are expensed as incurred, as recoverability of such expenditures is uncertain. The Company includes all external costs related to the filing of patents in Research, Development and Patents expenses. Such patent-related expenses totaled $ 0.4 million and $ 0.4 million for the years ended December 31, 2022 and 2021 , respectively. Leases The Company determines if an arrangement is a lease at inception and if so, determines whether the lease qualifies as an operating or finance lease. The Company does not recognize right-of-use assets and lease liabilities for leases with a term of 12 months or less and does not separate non-lease components from lease. Operating lease right-of-use assets and liabilities are recognized at commencement date based on the present value of lease payments over the lease term. Operating lease expense is recognized on a straight-line basis over the lease term and is included in general and administrative expense. As the Company’s operating leases do not provide an implicit rate, the Company uses its incremental borrowing rate based on the information available at commencement date in determining the present value of lease payments. The incremental borrowing rate is the rate that the Company would expect to pay to borrow on a collateralized and fully amortizing basis over a similar term an amount equal to the lease payments in a similar economic environment. Clinical Trial Accruals and Prepaid Expenses Costs for preclinical studies, clinical studies and manufacturing activities are recognized as research and development expenses based on an evaluation of the progress by Company vendors towards completion of specific tasks, using data such as patient enrollment, clinical site activations or information provided to the Company by such vendors regarding their actual costs incurred. Payments for these activities are based on the terms of individual contracts and payment timing may differ significantly from the period in which the services are performed. The Company determines accrual estimates through reports from and discussions with applicable personnel and outside service providers as to the progress or state of completion of studies, or the services completed. The Company’s estimates of accrued expenses as of each balance sheet date are based on the facts and circumstances known at the time. Costs that are paid in advance of performance are deferred as a prepaid expense and amortized over the service period as the services are provided. As of December 31, 2022, the Company recorded $ 1.5 million and $ 0.3 million in clinical trial accruals and prepaid expenses, respectively. As of December 31, 2021, the Company recorded $ 1.1 million and $ 0.4 million in clinical trial accruals and prepaid expenses, respectively. Share-Based Compensation The Company estimates the fair value of stock options using the Black-Scholes option pricing model on the date of grant. The fair value of equity instruments expected to vest are recognized and amortized on a straight-line basis over the requisite service period of the award, which is generally three to four years ; however, the Company’s equity compensation plans provide for any vesting schedule as the board may deem appropriate. Forfeitures are recognized as they occur. The Company issues employee performance-based stock options, the vesting of which is based on a determination made by the board of directors as to the achievement of certain corporate objectives at the end of the performance period. The grant date of such awards is the date on which the board of directors makes its determination. For periods preceding the grant date, the expense related to these awards is measured based on their fair value at each reporting date and the expected number of options based upon the expected performance compared to the performance objectives. Net Loss Per Share The Company computes basic net loss per share using the weighted average number of common shares outstanding during the period. Diluted net loss per share is based upon the weighted average number of common shares and potentially dilutive securities (common share equivalents) outstanding during the period. Common share equivalents outstanding, determined using the treasury stock method, are comprised of shares that may be issued under the Company’s outstanding stock option agreements. Common share equivalents are excluded from the diluted net loss per share calculation if their effect is anti-dilutive. Potentially dilutive outstanding securities of 7,985,250 and 7,974,250 for the years ended December 31, 2022 and 2021 , respectively, were excluded from diluted net loss per common share because of their anti-dilutive effect. Recently Issued Accounting Pronouncements In June 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2016-13, Financial Instruments— Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments (“ASU 2016-13”). The ASU introduced a new credit loss methodology, the Current Expected Credit Losses (“CECL”) methodology, which requires earlier recognition of credit losses, while also providing additional transparency about credit risk. The CECL methodology utilizes a lifetime “expected credit loss” measurement objective for the recognition of credit losses for loans, held-to maturity debt securities, trade receivables and other receivables measured at amortized cost at the time the financial asset is originated or acquired. Subsequent to the issuance of ASU 2016-13, the FASB issued several additional ASUs to clarify implementation guidance, provide narrow-scope improvements and provide additional disclosure guidance. In November 2019, the FASB issued an amendment making this ASU effective for fiscal years beginning after December 15, 2022 for smaller reporting companies. The new standard was effective for the Company on January 1, 2023. There was no impact on the consolidated financial statements upon adoption of this standard on January 1, 2023. In August 2020, the FASB issued ASU No. 2020-06, Debt – Debt with Conversion and Other Options (Subtopic 470-20) and Derivatives and Hedging – Contracts in Entity’s Own Equity (Subtopic 815-40) (“ASU 2020-06”). ASU 2020-06 simplifies the accounting for convertible debt instruments by reducing the number of accounting models and the number of embedded features that could be recognized separately from the host contract. Consequently, more convertible debt instruments will be accounted for as a single liability measured at its amortized cost, as long as no other features require bifurcation and recognition as derivatives. ASU 2020-06 also requires use of the if-converted method in the diluted earnings per share calculation for convertible instruments. ASU 2020-06 is effective for fiscal years beginning after December 15, 2023, and interim periods within those fiscal years for smaller reporting companies, with early adoption permitted. The new standard will be effective for the Company on January 1, 2024 or at such earlier time where it is no longer a smaller reporting company. The Company is currently evaluating the potential impact that this standard may have on its consolidated financial statements and related disclosures.

Revenue Recognition

Revenue Recognition	12 Months Ended
	Dec. 31, 2022
Revenue from Contract with Customer [Abstract]
Revenue Recognition	2. Revenue Recognition Revenue Recognition Policy Revenues historically have consisted mainly of research and development services performed under a contract with a customer. The Company evaluates the separate performance obligation(s) under each contract, allocates the transaction price to each performance obligation considering the estimated stand-alone selling prices of the services and recognizes revenue upon the satisfaction of such obligations at a point in time or over time dependent on the satisfaction of one of the following criteria: (1) the customer simultaneously receives and consumes the economic benefits provided by the vendor’s performance (2) the vendor creates or enhances an asset controlled by the customer (3) the vendor’s performance does not create an asset for which the vendor has an alternative use, and (4) the vendor has an enforceable right to payment for performance completed to date. Kissei Pharmaceutical Co., Ltd In October 2011, the Company entered into a collaboration agreement with Kissei Pharmaceutical Co., Ltd., (“Kissei”), to perform research and development services relating to MN-221 (bedoradrine) in exchange for a non-refundable upfront payment of $ 2.5 million. The Company assessed the services in accordance with the authoritative guidance and concluded that its met the definition of a collaborative arrangement per Accounting Standards Codification (ASC) 808, Collaborative Arrangements (“ASC 808”) which is outside of the scope of ASC 606, Revenue from Contracts with Customers (“ASC 606”). Since ASC 808 did not provide recognition and measurement guidance for collaborative arrangements, the Company analogized to ASC 606 and concluded that the two studies to be performed under the agreement represented two separate performance obligations. No services have been provided and no revenue has been recognized under the collaboration agreement subsequent to completion of the first study in 2013. In October 2021, the Company refunded $ 1.3 million of the prepayment. As of December 31, 2021, the Company and Kissei were working to mutually terminate the collaboration agreement and on October 24, 2022, the Company and Kissei finalized the termination of the collaboration agreement and canceled the second study contemplated thereunder. The Company has no further financial obligations to Kissei. Genzyme Corporation In December 2005, Avigen, Inc. and Genzyme Corporation (“Genzyme”) entered into an Assignment Agreement (the “Genzyme Agreement”) in which Genzyme acquired certain gene therapy intellectual property, programs and other related assets from Avigen, Inc. in exchange for an initial $ 12 million payment. Avigen could also receive additional development milestone payments, sublicensing fees, and royalty payments based on the successful development of products by Genzyme utilizing technologies previously developed by Avigen. The Company subsequently acquired Avigen in December 2009 along with Avigen’s rights and obligations under the Genzyme Agreement. If Genzyme fails to diligently pursue the commercialization or marketing of products using the assigned technology, as specified in the Genzyme Agreement, some of the rights assigned could revert back to the Company at a future date. The development milestones outlined in the Genzyme Agreement did not meet the definition of a substantive milestone obligation under authoritative guidance on revenue recognition for milestone payments, as Genzyme was responsible for the development of the product and there is no further substantive service effort required by the Company. In March 2021, the Company received notice that a gene therapy product based on AAV (adeno-associated virus) vector technology, which was covered under the Genzyme Agreement, achieved two clinical development milestones, triggering two milestone payments. Accordingly, the Company recognized revenue of $ 4.0 million for the year ended December 31, 2021.

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2022
Fair Value Disclosures [Abstract]
Fair Value Measurements	3. Fair Value Measurements Fair value is an exit price, representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. As such, fair value is a market-based measurement that should be determined based on assumptions that market participants would use in pricing an asset or liability. As a basis for considering such assumptions, a three-tier fair value hierarchy has been established, which prioritizes the inputs used in measuring fair value as follows: Level 1: Observable inputs such as quoted prices in active markets; Level 2: Inputs are quoted prices for similar items in active markets or inputs are quoted prices for identical or similar items in markets that are not active near the measurement date; and Level 3: Unobservable inputs due to little or no market data, which require the reporting entity to develop its own assumptions The carrying amount and approximate fair value of financial instruments as of December 31, 2022 and 2021, were as follows: December 31, 2022 December 31, 2021 Carrying Amount Fair Value Carrying Amount Fair Value Valuation Inputs Cash equivalents: Money market funds $ 704,882 $ 704,882 $ 694,293 $ 694,293 Level 1 Investments: Bank certificates of deposit $ 39,982,213 $ 39,982,213 — — Level 2 Short-term investments consisting of bank certificates of deposit with an original purchased maturity greater than three months are classified as held-to-maturity and are stated at amortized cost, which approximates fair value due to the short-term maturities and market rates of interest of these instruments.

Balance Sheet Details

Balance Sheet Details	12 Months Ended
	Dec. 31, 2022
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Balance Sheet Details	4. Balance Sheet Details Property and Equipment Property and equipment, net, consist of the following: December 31, 2022 2021 Leasehold improvements $ 13,532 $ 15,409 Furniture and equipment 121,909 124,731 Software 342,628 342,628 478,069 482,768 Less accumulated depreciation and amortization ( 432,800 ) ( 425,203 ) Property and equipment, net $ 45,269 $ 57,565 The Company uses the straight-line method to record depreciation expense with useful lives of three to five years . Leasehold improvements are amortized over a useful life of five years . Depreciation and amortization of property and equipment of $ 17,707 and $ 26,149 was recorded for the years ended December 31, 2022 and 2021, respectively. Accrued Liabilities and Other Current Liabilities Accrued liabilities and other current liabilities consist of the following: December 31, 2022 2021 Accrued compensation $ 920,166 $ 636,481 Clinical trial accruals 1,462,354 1,076,411 Professional services fees 38,688 38,041 Other 184,100 547,270 Total accrued liabilities and other current liabilities $ 2,605,308 $ 2,298,203

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2022
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	5. Commitments and Contingencies Lease Commitments The Company has operating leases primarily for real estate in the United States and Japan. The United States lease is for the Company’s headquarters in San Diego and has a term of five years ending January 31, 2027 , with annual escalations. The Company’s lease in Tokyo, Japan has a term of two years ending May 2023 with an auto-renewal , two-ye ar extension. The real estate operating leases are included in "Right-of-use asset" on the Company's balance sheet and represents the Company’s right to use the underlying assets for the lease term. The Company’s obligation to make lease payments are included in "Operating lease liability" and "Other non-current liabilities" on the Company's consolidated balance sheet. Information related to the Company’s right-of-use assets and related lease liabilities are as follows: Year Ended 2022 2021 Cash paid for operating lease liabilities $ 198,035 $ 242,676 Operating lease costs 248,610 228,779 Right-of-use assets obtained in exchange for new operating lease obligations — 870,373 Current operating lease liabilities $ 157,505 $ 131,965 Non-current operating lease liabilities 523,619 694,674 Total operating lease liabilities $ 681,124 $ 826,639 Weighted-average remaining lease term 3.90 4.54 Weighted-average discount rate 9.8 % 9.8 % Maturities of operating lease liabilities as of December 31, 2022 were as follows: 2023 $ 216,154 2024 189,170 2025 197,585 2026 206,483 2027 17,269 Thereafter - Total minimum payments $ 826,661 Less imputed interest ( 145,537 ) Total lease liabilities $ 681,124 Product Liability The Company’s business exposes it to liability risks from its potential drug products. A successful product liability claim or series of claims brought against the Company could result in the payment of significant amounts of money and divert management’s attention from running the business. The Company may not be able to maintain insurance on acceptable terms, or the insurance may not provide adequate protection in the case of a product liability claim. To the extent that product liability insurance, if available, does not cover potential claims, the Company would be required to self-insure the risks associated with such claims. The Company believes it carries reasonably adequate insurance for product liability. License and Research Agreements The Company has entered into in-licensing agreements with various pharmaceutical companies. Under the terms of these agreements, the Company has received licenses to research, know-how and technology claimed, in certain patents or patent applications. Under these license agreements, the Company is generally required to make upfront payments and additional payments upon the achievement of milestones and/or royalties on future sales of products until the later of the expiration of the applicable patent or the applicable last date of market exclusivity after the first commercial sale, on a country-by-country basis. No milestone payments have been made under these agreements during the years ended December 31, 2022 and 2021 . For products currently in development, future potential milestone payments based on product development of MN-166 (ibudilast) and MN-001 (tipelukast) are $ 10 million as of December 31, 2022. For all other products, future potential milestone payments related to development milestones and commercialization milestones totale d $ 16.5 million as of December 31, 2022. There are no minimum royalties required under any of the license agreements. The Company is unable to estimate with certainty the timing on when these milestone payments will occur as these payments are dependent upon the progress of the Company’s product development programs. Legal Proceedings From time to time, the Company may be subject to legal proceedings and claims in the ordinary course of business. The Company is not aware of any such proceedings or claims that it believes will have, individually or in aggregate, a material adverse effect on its business, financial condition or results of operations.

Stock-based Compensation

Stock-based Compensation	12 Months Ended
	Dec. 31, 2022
Share-Based Payment Arrangement [Abstract]
Stock-based Compensation	6. Stock-based Compensation Stock Incentive Plans In June 2013, the Company adopted the 2013 Equity Incentive Plan ("2013 Plan"), under which the Company may grant stock options, stock appreciation rights, restricted stock, restricted stock units and other awards to individuals who are then employees, officers, non-employee directors or consultants of the Company or its subsidiaries. The 2013 Plan is the successor to the Company’s Amended and Restated 2004 Stock Incentive Plan, or 2004 Plan. A total of 8,700,000 shares of common stock are reserved for issuance under the 2013 Plan. In addition, “returning shares” that may become available from time to time are added back to the plan. Returning shares are shares that are subject to outstanding awards granted under the 2004 Plan that expire or terminate prior to exercise or settlement, are forfeited because of the failure to vest, are repurchased, or are withheld to satisfy tax withholding or purchase price obligations in connection with such awards. Although the Company no longer grants equity awards under the 2004 Plan, all outstanding stock awards granted under the 2004 Plan will continue to be subject to the terms and conditions as set forth in the agreements evidencing such stock awards and the terms of the 2004 Plan. As of December 31, 2022, 1,949,317 shares remain available for future grant under the 2013 Plan. Certain of the employee stock options granted contain performance conditions, the vesting of which is based on a determination made by the board of directors or its compensation committee as to the achievement of certain corporate objectives at the end of the performance period. The grant date of such awards is the date on which the board of directors or its compensation committee makes its determination. For periods preceding the grant date, the expense related to these awards is measured based on their fair value at each reporting date. The estimated fair value of the performance awards granted and the resulting expense is based upon a certain level of achievement of the corporate objectives and other assumptions in determining fair value. The amount of expense ultimately recognized upon the grant date at completion of the performance period could change from the estimate as a result of various factors, including the level of achievement of the corporate objectives, changes in the assumptions used in the Black-Scholes model in determining fair value or fluctuations in the Company’s stock price during the performance period. As of December 31, 2022 , there were a total of 533,700 shares u nderlying performance options that were subject to vesting based on achievement of corporate objectives for 2022. In January 2023, the compensation committee and the board of directors determined that the performance milestones were achieved at the 95 % level and accordingly 507,015 of these options vested and the remaining shares were forfeited. Stock Options Options granted under the 2013 Plan and 2004 Plan have terms of ten years from the date of grant unless earlier terminated and generally vest over a one to four-year period. The exercise price of all options granted during the years ended December 31, 2022 and 2021 was equal to the market value of the Company’s common stock on the date of grant. A summary of stock option activity and related information for the years ended December 31, 2022 and 2021 is as follows: Number of Shares Weighted Average Outstanding at December 31, 2020 7,401,387 $ 5.70 Granted 1,315,000 $ 5.82 Exercised ( 360,955 ) $ 2.47 Cancelled ( 381,182 ) $ 6.77 Outstanding at December 31, 2021 7,974,250 $ 5.81 Granted 591,700 $ 2.28 Exercised ( 3,000 ) $ 2.64 Cancelled ( 577,700 ) $ 5.85 Outstanding at December 31, 2022 7,985,250 $ 5.55 Exercisable at December 31, 2022 7,394,381 $ 5.80 Number of Shares Weighted Average Grant-Date Fair Value Non-vested at December 31, 2021 1,286,333 $ 3.54 Granted 591,700 $ 1.47 Vested ( 738,134 ) $ 3.47 Forfeitures ( 549,030 ) $ 3.58 Non-vested at December 31, 2022 590,869 $ 1.52 The aggregate intrinsic value of options exercised was $ 1,410 an d $ 0.7 million for the years ended December 31, 2022 and 2021, respectively. Options outstanding and exercisable at December 31, 2022 had a weighted average contractual life o f 4.89 years an d 4. 56 years, respectively. As of December 31, 2022 and 2021 , the total intrinsic value of options outstanding was $ 0 and $ 32,840 , respectively. Total intrinsic value of options exercisable was $ 0 and $ 32,840 as of December 31, 2022 and 2021, respectively. Total fair value of options vested was $ 2.6 million a nd $ 4.2 million for the years ended December 31, 2022 and 2021, respectively. Employee Stock Purchase Plan Under the Company’s 2007 Employee Stock Purchase Plan (ESPP), 300,000 shares of common stock were originally reserved for issuance. In addition, the shares reserved automatically increase each year by a number equal to the lesser of: (i) 15,000 shares; (ii) 1 % of the outstanding shares of common stock on the last day of the immediately preceding fiscal year; or (iii) such amount as determined by the Board . The ESPP permits full-time employees to purchase common stock through payroll deductions (which cannot exceed 15 % of each employee’s compensation) at the lower of 85 % of fair market value at the beginning of the offering period or the end of each six-month offering period. The ESPP is considered a compensatory plan and the Company records compensation expense. For the year ended December 31, 2021 an aggregate of 1,424 shares were issued under the ESPP. No further shares will be issued under the ESPP. Compensation Expense The estimated fair value of each stock option award was determined on the date of grant using the Black-Scholes option valuation model with the following weighted-average assumptions for stock option grants: Year Ended 2022 2021 Stock Options Risk-free interest rate 3.88 % 0.58 % Expected volatility of common stock 78.81 % 72.41 % Dividend yield 0.00 % 0.00 % Expected option term (in years) 4.70 5.48 The estimated fair value of employee stock purchase rights under the Company’s ESPP was determined on the date of grant using the Black-Scholes option valuation model with the following weighted-average assumptions: Year Ended 2022 2021 Employee Stock Purchase Plan Risk-free interest rate — 0.05 % Expected volatility of common stock — 83.40 % Dividend yield — 0.00 % Expected option term (in years) — 0.5 The risk-free interest rate assumption is based upon observed interest rates appropriate for the expected term of employee stock options. The expected volatility is based on the historical volatility of the Company’s common stock. The Company has not paid nor does the Company anticipate paying dividends on its common stock in the foreseeable future. The expected term of employee stock options is based on the simplified method as provided by the authoritative guidance on stock compensation, as the historical stock option exercise experience does not provide a reasonable basis to estimate the expected term. The weighted-average fair value of each stock option granted during the years ended December 31, 2022 and 2021, estimated as of the grant date using the Black-Scholes option valuation model, was $ 1.47 per option and $ 3.51 per option, respectively. Stock-based compensation expense for stock option awards and ESPP shares are reflected in total operating expenses for each respective year. The following table summarizes stock-based compensation expense for the years ended December 31, 2022 and 2021: December 31, 2022 2021 Research, development and patents $ 237,071 $ 640,340 General and administrative 405,451 1,077,173 Total stock-based compensation expense $ 642,522 $ 1,717,513 As of December 31, 2022, there was $ 0.2 million of unamortized compensation cost related to unvested stock option awards which is expected to be recognized over a remaining weighted-average vesting period of 0.20 years, on a straight-line basis.

Stockholders' Equity

Stockholders' Equity	12 Months Ended
	Dec. 31, 2022
Equity [Abstract]
Stockholders' Equity	7. Stockholders’ Equity At-The-Market Issuance Sales Agreement On August 23, 2019, the Company entered into an at the market issuance sales agreement, which was amended on August 26, 2022 (as amended, the “ATM Agreement”) with B. Riley FBR, Inc. (B. Riley FBR) pursuant to which the Company may sell common stock through B. Riley FBR from time to time up to an aggregate offering price of $ 75.0 million. Sales of the Company’s common stock through B. Riley FBR, if any, will be made by any method that is deemed to be an “at-the-market” equity offering as defined in Rule 415 promulgated under the Securities Act of 1933, as amended, including sales made directly on NASDAQ, on any other existing trading market for the common stock or through a market maker. B. Riley FBR may also sell the common stock in privately negotiated transactions, subject to the Company’s prior approval. The Company agreed to pay B. Riley FBR an aggregate commission rate of up to 3.5 % of the gross proceeds of any common stock sold under this agreement. Proceeds from sales of common stock will depend on the number of shares of common stock sold to B. Riley FBR and the per share purchase price of each transaction. No shares of common stock were sold under the ATM Agreement in the years ended December 31, 2022 and 2021, respectively. Private Placement Transactions On January 29, 2021, the Company sold and issued to an investor 3,656,307 shares of the Company’s common stock at a price of $ 5.47 per share for approximately $ 20 million in cash proceeds, net of approximately $ 0.1 million in issuance costs, in a private placement pursuant to the terms and conditions of a Securities Purchase Agreement dated as of January 11, 2021 by and between the Company and such investor. Common Stock Reserved for Future Issuance The following table summarizes common stock reserved for future issuance at December 31, 2022: Common stock reserved for issuance upon exercise of 7,985,250 Common stock reserved for future equity awards (under 1,949,317 9,934,567

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2022
Income Tax Disclosure [Abstract]
Income Taxes	8. Income Taxes A reconciliation of loss before income taxes for domestic and foreign locations for the years ended December 31, 2022 and 2021 is as follows: Year Ended 2022 2021 United States $ ( 14,084,240 ) $ ( 10,145,822 ) Foreign 17,979 14,138 Loss before income taxes $ ( 14,066,261 ) $ ( 10,131,684 ) A reconciliation of income tax expense for the years ended December 31, 2022 and 2021 is as follows: Year Ended Current: 2022 2021 Federal $ — $ — State — — Foreign ( 2,822 ) ( 2,568 ) Total current income tax expense ( 2,822 ) ( 2,568 ) Deferred: Federal — — State — — Foreign — — Total deferred income tax expense — — Total income tax expense $ ( 2,822 ) $ ( 2,568 ) The significant components of deferred income taxes at December 31, 2022 and 2021 are as follows: Year Ended Deferred tax assets: 2022 2021 Net operating loss carryforwards $ 70,142,367 $ 68,485,037 Capitalized licenses 934 30,784 Research tax credits 9,629,956 9,262,071 Stock options 1,526,644 1,601,862 Other, net 390,610 423,279 Right-of-use asset 180,938 196,059 Research and experimentation capitalization 1,795,580 — Total deferred tax assets 83,667,029 79,999,092 Deferred tax liabilities Right-of-use liability ( 166,786 ) ( 196,059 ) In-process research and development ( 1,343,213 ) ( 1,343,213 ) Total deferred tax liabilities ( 1,509,999 ) ( 1,539,272 ) Net deferred tax assets 82,157,030 78,459,820 Valuation allowance ( 82,358,822 ) ( 78,661,612 ) Net deferred tax liability $ ( 201,792 ) $ ( 201,792 ) The Company has established a valuation allowance against net deferred tax assets due to the uncertainty that such assets will be realized. The net change in the valuation allowance during the year ended December 31, 2022 was an increase of $ 3.7 million. The Company periodically evaluates the recoverability of the deferred tax assets. At such time as it is determined that it is more likely than not that deferred tax assets will be realizable, the valuation allowance will be reduced. At December 31, 2022 , the Company has federal and California net operating loss (NOL) carryforwards of approximately $ 276.6 million and $ 182.9 million, respectively. $ 232.3 million of federal NOL carryforwards began to expire in 2022 , $ 44.3 million of federal NOL carryforwards can be carried forward indefinitely, and the California NOL carryforwards begin to expire in 2028 . At December 31, 2022 , the Company also had federal and California research tax credit carry-forwards of approximately $ 7.8 million and $ 2.3 million, respectively. The federal research tax credit carryforwards will begin to expire in 2024 , and the California research tax credit carryforward does not expire and can be carried forward indefinitely until utilized. The above NOL carryforward and the research tax credit carryforwards are subject to an annual limitation under Section 382 and 383 of the Internal Revenue Code of 1986, and similar state provisions due to ownership change limitations that have occurred which will limit the amount of NOL and tax credit carryforwards that can be utilized to offset future taxable income and tax, respectively. In general, an ownership change, as defined by Section 382 and 383, results from transactions increasing ownership of certain stockholders or public groups in the stock of the corporation by more than 50 percentage points over a three-year period. The Company has not completed an IRC Section 382/383 analysis since 2011 regarding the limitation of net operating loss and research and development credit carryforwards. There is a risk that additional changes in ownership have occurred since the completion of the Company’s analysis, which was through December 2011. If a change in ownership were to have occurred, additional NOL and tax credit carryforwards could be eliminated or restricted. If eliminated, the related asset would be removed from the deferred tax asset schedule with a corresponding reduction in the valuation allowance. Due to the existence of the valuation allowance, limitations created by future ownership changes, if any, related to the Company’s operations in the United States will not impact the Company’s effective tax rate. A reconciliation of the federal statutory income tax rate to the Company’s effective income tax rate is as follows: Year Ended 2022 2021 Federal statutory income tax rate 21.0 % 21.0 % State income taxes, net of federal benefit 6.4 2.7 Tax credits 2.6 2.8 Change in valuation allowance ( 26.4 ) 3.5 Permanent differences ( 0.3 ) ( 0.2 ) Expiration of attributes ( 1.3 ) ( 10.4 ) Stock compensation ( 1.9 ) ( 12.4 ) Uncertain tax positions — ( 7.0 ) Other ( 0.1 ) — Provision for income taxes 0.0 % 0.0 % The Company determines its uncertain tax positions based on a determination of whether and how much of a tax benefit taken by the Company in its tax filings is more likely than not to be sustained upon examination by the relevant income tax authorities. The following table summarizes the activity related to the Company’s unrecognized tax benefits: Year Ended 2022 2021 Gross unrecognized tax benefits at January 1 $ 893,371 $ - Additions for tax positions taken in the prior year 3,610 - Additions for tax positions taken in the current year - 893,371 Gross unrecognized tax benefits at December 31 $ 896,981 $ 893,371 If recognized, none of the unrecognized tax benefits as of December 31, 2022 would reduce the annual effective tax rate, primarily due to corresponding adjustments to the valuation allowance. The Company files income tax returns in the United States, California and foreign jurisdictions. Due to the Company’s losses incurred, the Company is essentially subject to income tax examination by tax authorities from inception to date. The Company’s policy is to recognize interest expense and penalties related to income tax matters as tax expense. At December 31, 2022 , there are no significant accruals for interest related to unrecognized tax benefits or tax penalties. The Company does not expect the unrecognized tax benefits to change significantly over the next twelve months.

Employee Savings Plan

Employee Savings Plan	12 Months Ended
	Dec. 31, 2022
Retirement Benefits [Abstract]
Employee Savings Plan	9. Employee Savings Plan The Company has an employee savings plan available to substantially all employees. Under the plan, an employee may elect salary reductions which are contributed to the plan. The plan provides for discretionary contributions by the Company, which totaled $ 75,859 and $ 72,330 for the years ended December 31, 2022 and 2021 , respectively.

Organization and Summary of S_2

Organization and Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2022
Accounting Policies [Abstract]
Principles of Consolidation	Principles of Consolidation The consolidated financial statements include the accounts of MediciNova, Inc. and its wholly owned subsidiaries MediciNova Japan, Inc., MediciNova (Europe) Limited, MediciNova Europe GmbH and Avigen Inc. The financial statements of the Company’s foreign subsidiaries are measured using their local currency as the functional currency. The resulting translation adjustments are recorded as a component of other comprehensive income or loss. Intercompany transaction gains or losses at each period end are included as translation adjustments and recorded within other comprehensive income or loss. All intercompany transactions and balances are eliminated in consolidation.
Segment Reporting	Segment Reporting Operating segments are identified as components of an enterprise about which separate discrete financial information is available for evaluation by the chief operating decision-maker in making decisions regarding resource allocation and assessing performance. The Company operates in a single operating segment – the acquisition and development of small molecule therapeutics for the treatment of serious diseases with unmet medical needs.
Impact of COVID-19 on the Company’s Business	Impact of COVID-19 on the Company’s Business The pandemic caused by an outbreak of a new strain of coronavirus (“COVID-19” or “the pandemic”) has resulted, and is likely to continue to result, in significant national and global economic disruption and may adversely affect the Company’s business. So far, the Company has experienced certain adverse effects on its business as well as been provided certain opportunities as a result of the pandemic. The pandemic caused a decrease in the number of patient visits at some clinical trial sites which the Company believes resulted in slower enrollment in the Company's clinical trials than would have occurred without the pandemic. However, the Company has seen an increase in the number of patient visits compared to earlier in the pandemic and the Company continues to enroll patients in clinical trials. Throughout the pandemic, the Company has continued with routine clinical trial activities including executing new clinical trial agreements, negotiating budgets, institutional review board (IRB) approvals, site training, and other activities related to the initiation of new clinical trials and the opening of new clinical trial sites, although some of these activities took longer to complete than what the Company experienced prior to the pandemic. The pandemic created certain new opportunities for the Company's clinical development and the Company has pursued those opportunities. Following the outbreak of the pandemic, the Company designed a clinical trial to evaluate MN-166 (ibudilast) for prevention of acute respiratory distress syndrome (ARDS) caused by COVID-19. The Company continues to actively monitor the pandemic situation and the possible effects on its financial condition, liquidity, operations, suppliers, industry, and workforce.
Use of Estimates	Use of Estimates The preparation of the consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates.
Cash and Cash Equivalents	Cash and Cash Equivalents Cash and cash equivalents consist of cash and other highly liquid investments, including money market accounts, with original maturities of three months or less from the date of purchase.
Investments	Investments Investments purchased with an original maturity of greater than three months are classified as investments. Investments are stated at fair value and are classified as current or non-current based on the nature of the securities as well as their stated maturities. As of December 31, 2022 , investments consisted of bank certificates of deposit with original purchased maturity dates between seven and 13 months .
Concentrations and Credit Risk	Concentrations and Credit Risk The Company maintains cash balances and has purchased certificates of deposit at various financial institutions and such balances and certificates of deposit commonly exceed the $ 250,000 amount insured by the Federal Deposit Insurance Corporation. The Company also maintains money market funds at various financial institutions which are not federally insured although are invested primarily in U.S. government securities. The Company has not experienced any losses in such accounts and management believes that the Company does not have significant credit risk with respect to such cash and cash equivalents.
Fair Value of Financial Instruments	Fair Value of Financial Instruments Financial instruments, including cash equivalents and accounts payable, are carried at cost, which management believes approximates fair value because of the short-term nature of these instruments.
IPR&D, Long-Lived Assets and Goodwill	IPR&D, Long-Lived Assets and Goodwill Amounts incurred related to in-process research and development (“IPR&D”) or asset purchases of IPR&D are expensed as incurred. Amounts allocated to IPR&D in connection with a business combination are recorded at fair value and are considered indefinite-lived intangible assets until completion or abandonment of the associated research and development efforts. If and when development is complete, which generally occurs when regulatory approval to market a product is obtained, the associated assets are deemed finite-lived and amortized over a period that best reflects the economic benefits provided by these assets. During the period the assets are considered indefinite-lived, they will not be amortized but will be tested annually for impairment or more frequently if indicators of impairment exist. The Company first assesses qualitative factors to determine whether it is more likely than not that the fair value of the IPR&D is less than its carrying amount as a basis for determining whether it is necessary to perform a quantitative assessment. If, after assessing qualitative factors, the Company determines it is not more likely than not that the fair value is less than its carrying amount, then a quantitative assessment is unnecessary. If the quantitative assessment is deemed necessary, the excess of the carrying value over fair value will be recorded as an impairment. The qualitative assessment focuses on the key inputs, assumptions and rationale utilized in the establishment of the carrying value and related changes since the last quantitative assessment. Based on the results of the Company’s annual qualitative assessment, the Company concluded that it is not more likely than not that IPR&D was impaired for any of the periods presented. The Company’s long-lived assets are reviewed for impairment whenever events or changes in circumstances indicate that the carrying value of an asset (or asset group) may not be recoverable, and the Company will perform an impairment analysis. Long-lived assets are deemed to be impaired when the undiscounted cash flows expected to be generated by the asset (or asset group) are less than the asset’s carrying amount. Any required impairment loss would be measured as the amount by which the asset’s (or asset group’s) carrying value exceeds its fair value and would be recorded as a reduction in the carrying value of the related asset and a charge to operating expense. There were no events or changes in circumstances to indicate that the carrying value of an asset (or asset group) may not be recoverable for any of the periods presented. Goodwill is reviewed for impairment annually (as of December 31st) or more frequently if indicators of impairment exist. As the Company operates in a single operating segment and reporting unit, goodwill is assessed at a consolidated level. The Company first assesses qualitative factors to determine whether it is more likely than not that the fair value of the reporting unit is less than its carrying amount, including goodwill. If so, the Company will proceed with a quantitative assessment that compares the fair value of the reporting unit with its carrying amount. If the fair value exceeds the carrying value as a result of either the qualitative or quantitative test, goodwill is not considered impaired. The qualitative factors include economic environment, business climate, market capitalization, operating performance, competition, and other factors. The Company placed the highest weight in excess cushion of the market capitalization to the equity carrying value in the analysis. Based on the results of the Company’s annual qualitative assessment, the Company concluded that it is not more likely than not that goodwill was impaired for any of the periods presented.
Research, Development and Patents	Research, Development and Patents Research and development costs are expensed in the period incurred. Research and development costs primarily consist of salaries and related expenses for personnel, facilities and depreciation, research and development supplies, licenses and outside services. Such research and development costs totaled $ 8.7 million and $ 8.1 million for the years ended December 31, 2022 and 2021, respectively. Costs related to filing and pursuing patent applications are expensed as incurred, as recoverability of such expenditures is uncertain. The Company includes all external costs related to the filing of patents in Research, Development and Patents expenses. Such patent-related expenses totaled $ 0.4 million and $ 0.4 million for the years ended December 31, 2022 and 2021 , respectively.
Leases	Leases The Company determines if an arrangement is a lease at inception and if so, determines whether the lease qualifies as an operating or finance lease. The Company does not recognize right-of-use assets and lease liabilities for leases with a term of 12 months or less and does not separate non-lease components from lease. Operating lease right-of-use assets and liabilities are recognized at commencement date based on the present value of lease payments over the lease term. Operating lease expense is recognized on a straight-line basis over the lease term and is included in general and administrative expense. As the Company’s operating leases do not provide an implicit rate, the Company uses its incremental borrowing rate based on the information available at commencement date in determining the present value of lease payments. The incremental borrowing rate is the rate that the Company would expect to pay to borrow on a collateralized and fully amortizing basis over a similar term an amount equal to the lease payments in a similar economic environment.
Clinical Trial Accruals and Prepaid Expenses	Clinical Trial Accruals and Prepaid Expenses Costs for preclinical studies, clinical studies and manufacturing activities are recognized as research and development expenses based on an evaluation of the progress by Company vendors towards completion of specific tasks, using data such as patient enrollment, clinical site activations or information provided to the Company by such vendors regarding their actual costs incurred. Payments for these activities are based on the terms of individual contracts and payment timing may differ significantly from the period in which the services are performed. The Company determines accrual estimates through reports from and discussions with applicable personnel and outside service providers as to the progress or state of completion of studies, or the services completed. The Company’s estimates of accrued expenses as of each balance sheet date are based on the facts and circumstances known at the time. Costs that are paid in advance of performance are deferred as a prepaid expense and amortized over the service period as the services are provided. As of December 31, 2022, the Company recorded $ 1.5 million and $ 0.3 million in clinical trial accruals and prepaid expenses, respectively. As of December 31, 2021, the Company recorded $ 1.1 million and $ 0.4 million in clinical trial accruals and prepaid expenses, respectively.
Share-Based Compensation	Share-Based Compensation The Company estimates the fair value of stock options using the Black-Scholes option pricing model on the date of grant. The fair value of equity instruments expected to vest are recognized and amortized on a straight-line basis over the requisite service period of the award, which is generally three to four years ; however, the Company’s equity compensation plans provide for any vesting schedule as the board may deem appropriate. Forfeitures are recognized as they occur. The Company issues employee performance-based stock options, the vesting of which is based on a determination made by the board of directors as to the achievement of certain corporate objectives at the end of the performance period. The grant date of such awards is the date on which the board of directors makes its determination. For periods preceding the grant date, the expense related to these awards is measured based on their fair value at each reporting date and the expected number of options based upon the expected performance compared to the performance objectives.
Net Loss Per Share	Net Loss Per Share The Company computes basic net loss per share using the weighted average number of common shares outstanding during the period. Diluted net loss per share is based upon the weighted average number of common shares and potentially dilutive securities (common share equivalents) outstanding during the period. Common share equivalents outstanding, determined using the treasury stock method, are comprised of shares that may be issued under the Company’s outstanding stock option agreements. Common share equivalents are excluded from the diluted net loss per share calculation if their effect is anti-dilutive. Potentially dilutive outstanding securities of 7,985,250 and 7,974,250 for the years ended December 31, 2022 and 2021 , respectively, were excluded from diluted net loss per common share because of their anti-dilutive effect.
Recently Issued Accounting Pronouncements	Recently Issued Accounting Pronouncements In June 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2016-13, Financial Instruments— Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments (“ASU 2016-13”). The ASU introduced a new credit loss methodology, the Current Expected Credit Losses (“CECL”) methodology, which requires earlier recognition of credit losses, while also providing additional transparency about credit risk. The CECL methodology utilizes a lifetime “expected credit loss” measurement objective for the recognition of credit losses for loans, held-to maturity debt securities, trade receivables and other receivables measured at amortized cost at the time the financial asset is originated or acquired. Subsequent to the issuance of ASU 2016-13, the FASB issued several additional ASUs to clarify implementation guidance, provide narrow-scope improvements and provide additional disclosure guidance. In November 2019, the FASB issued an amendment making this ASU effective for fiscal years beginning after December 15, 2022 for smaller reporting companies. The new standard was effective for the Company on January 1, 2023. There was no impact on the consolidated financial statements upon adoption of this standard on January 1, 2023. In August 2020, the FASB issued ASU No. 2020-06, Debt – Debt with Conversion and Other Options (Subtopic 470-20) and Derivatives and Hedging – Contracts in Entity’s Own Equity (Subtopic 815-40) (“ASU 2020-06”). ASU 2020-06 simplifies the accounting for convertible debt instruments by reducing the number of accounting models and the number of embedded features that could be recognized separately from the host contract. Consequently, more convertible debt instruments will be accounted for as a single liability measured at its amortized cost, as long as no other features require bifurcation and recognition as derivatives. ASU 2020-06 also requires use of the if-converted method in the diluted earnings per share calculation for convertible instruments. ASU 2020-06 is effective for fiscal years beginning after December 15, 2023, and interim periods within those fiscal years for smaller reporting companies, with early adoption permitted. The new standard will be effective for the Company on January 1, 2024 or at such earlier time where it is no longer a smaller reporting company. The Company is currently evaluating the potential impact that this standard may have on its consolidated financial statements and related disclosures.
Revenue Recognition Policy	Revenue Recognition Policy Revenues historically have consisted mainly of research and development services performed under a contract with a customer. The Company evaluates the separate performance obligation(s) under each contract, allocates the transaction price to each performance obligation considering the estimated stand-alone selling prices of the services and recognizes revenue upon the satisfaction of such obligations at a point in time or over time dependent on the satisfaction of one of the following criteria: (1) the customer simultaneously receives and consumes the economic benefits provided by the vendor’s performance (2) the vendor creates or enhances an asset controlled by the customer (3) the vendor’s performance does not create an asset for which the vendor has an alternative use, and (4) the vendor has an enforceable right to payment for performance completed to date.

Balance Sheet Details (Tables)

Balance Sheet Details (Tables)	12 Months Ended
	Dec. 31, 2022
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Property and Equipment Net	Property and equipment, net, consist of the following: December 31, 2022 2021 Leasehold improvements $ 13,532 $ 15,409 Furniture and equipment 121,909 124,731 Software 342,628 342,628 478,069 482,768 Less accumulated depreciation and amortization ( 432,800 ) ( 425,203 ) Property and equipment, net $ 45,269 $ 57,565
Accrued Liabilities and Other Current Liabilities	Accrued liabilities and other current liabilities consist of the following: December 31, 2022 2021 Accrued compensation $ 920,166 $ 636,481 Clinical trial accruals 1,462,354 1,076,411 Professional services fees 38,688 38,041 Other 184,100 547,270 Total accrued liabilities and other current liabilities $ 2,605,308 $ 2,298,203

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2022
Fair Value Disclosures [Abstract]
Schedule of Carrying Amount and Approximate Fair Value of Financial Instruments	The carrying amount and approximate fair value of financial instruments as of December 31, 2022 and 2021, were as follows: December 31, 2022 December 31, 2021 Carrying Amount Fair Value Carrying Amount Fair Value Valuation Inputs Cash equivalents: Money market funds $ 704,882 $ 704,882 $ 694,293 $ 694,293 Level 1 Investments: Bank certificates of deposit $ 39,982,213 $ 39,982,213 — — Level 2

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2022
Commitments and Contingencies Disclosure [Abstract]
Schedule of Information Related to Right-of-Use Assets and Related Lease Liabilities	Information related to the Company’s right-of-use assets and related lease liabilities are as follows: Year Ended 2022 2021 Cash paid for operating lease liabilities $ 198,035 $ 242,676 Operating lease costs 248,610 228,779 Right-of-use assets obtained in exchange for new operating lease obligations — 870,373 Current operating lease liabilities $ 157,505 $ 131,965 Non-current operating lease liabilities 523,619 694,674 Total operating lease liabilities $ 681,124 $ 826,639 Weighted-average remaining lease term 3.90 4.54 Weighted-average discount rate 9.8 % 9.8 %
Schedule of Maturities of Operating Lease Liabilities	Maturities of operating lease liabilities as of December 31, 2022 were as follows: 2023 $ 216,154 2024 189,170 2025 197,585 2026 206,483 2027 17,269 Thereafter - Total minimum payments $ 826,661 Less imputed interest ( 145,537 ) Total lease liabilities $ 681,124

Stock-based Compensation (Table

Stock-based Compensation (Tables)	12 Months Ended
	Dec. 31, 2022
Share-Based Payment Arrangement [Abstract]
Summary of Stock Option Activity and Related Information	A summary of stock option activity and related information for the years ended December 31, 2022 and 2021 is as follows: Number of Shares Weighted Average Outstanding at December 31, 2020 7,401,387 $ 5.70 Granted 1,315,000 $ 5.82 Exercised ( 360,955 ) $ 2.47 Cancelled ( 381,182 ) $ 6.77 Outstanding at December 31, 2021 7,974,250 $ 5.81 Granted 591,700 $ 2.28 Exercised ( 3,000 ) $ 2.64 Cancelled ( 577,700 ) $ 5.85 Outstanding at December 31, 2022 7,985,250 $ 5.55 Exercisable at December 31, 2022 7,394,381 $ 5.80 Number of Shares Weighted Average Grant-Date Fair Value Non-vested at December 31, 2021 1,286,333 $ 3.54 Granted 591,700 $ 1.47 Vested ( 738,134 ) $ 3.47 Forfeitures ( 549,030 ) $ 3.58 Non-vested at December 31, 2022 590,869 $ 1.52
Weighted-Average Assumptions for Stock Option	The estimated fair value of each stock option award was determined on the date of grant using the Black-Scholes option valuation model with the following weighted-average assumptions for stock option grants: Year Ended 2022 2021 Stock Options Risk-free interest rate 3.88 % 0.58 % Expected volatility of common stock 78.81 % 72.41 % Dividend yield 0.00 % 0.00 % Expected option term (in years) 4.70 5.48
Weighted-Average Assumptions for ESPP	The estimated fair value of employee stock purchase rights under the Company’s ESPP was determined on the date of grant using the Black-Scholes option valuation model with the following weighted-average assumptions: Year Ended 2022 2021 Employee Stock Purchase Plan Risk-free interest rate — 0.05 % Expected volatility of common stock — 83.40 % Dividend yield — 0.00 % Expected option term (in years) — 0.5
Summary of Stock-based Compensation Expense	The following table summarizes stock-based compensation expense for the years ended December 31, 2022 and 2021: December 31, 2022 2021 Research, development and patents $ 237,071 $ 640,340 General and administrative 405,451 1,077,173 Total stock-based compensation expense $ 642,522 $ 1,717,513

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	12 Months Ended
	Dec. 31, 2022
Equity [Abstract]
Common Stock Reserved for Future Issuance	The following table summarizes common stock reserved for future issuance at December 31, 2022: Common stock reserved for issuance upon exercise of 7,985,250 Common stock reserved for future equity awards (under 1,949,317 9,934,567

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2022
Income Tax Disclosure [Abstract]
Reconciliation of Loss before Income Taxes for Domestic and Foreign Locations	A reconciliation of loss before income taxes for domestic and foreign locations for the years ended December 31, 2022 and 2021 is as follows: Year Ended 2022 2021 United States $ ( 14,084,240 ) $ ( 10,145,822 ) Foreign 17,979 14,138 Loss before income taxes $ ( 14,066,261 ) $ ( 10,131,684 )
Reconciliation of Income Tax Expense	A reconciliation of income tax expense for the years ended December 31, 2022 and 2021 is as follows: Year Ended Current: 2022 2021 Federal $ — $ — State — — Foreign ( 2,822 ) ( 2,568 ) Total current income tax expense ( 2,822 ) ( 2,568 ) Deferred: Federal — — State — — Foreign — — Total deferred income tax expense — — Total income tax expense $ ( 2,822 ) $ ( 2,568 )
Components of Deferred Income Taxes	The significant components of deferred income taxes at December 31, 2022 and 2021 are as follows: Year Ended Deferred tax assets: 2022 2021 Net operating loss carryforwards $ 70,142,367 $ 68,485,037 Capitalized licenses 934 30,784 Research tax credits 9,629,956 9,262,071 Stock options 1,526,644 1,601,862 Other, net 390,610 423,279 Right-of-use asset 180,938 196,059 Research and experimentation capitalization 1,795,580 — Total deferred tax assets 83,667,029 79,999,092 Deferred tax liabilities Right-of-use liability ( 166,786 ) ( 196,059 ) In-process research and development ( 1,343,213 ) ( 1,343,213 ) Total deferred tax liabilities ( 1,509,999 ) ( 1,539,272 ) Net deferred tax assets 82,157,030 78,459,820 Valuation allowance ( 82,358,822 ) ( 78,661,612 ) Net deferred tax liability $ ( 201,792 ) $ ( 201,792 )
Reconciliation of Federal Statutory Income Tax Rate to Effective Income Tax Rate	A reconciliation of the federal statutory income tax rate to the Company’s effective income tax rate is as follows: Year Ended 2022 2021 Federal statutory income tax rate 21.0 % 21.0 % State income taxes, net of federal benefit 6.4 2.7 Tax credits 2.6 2.8 Change in valuation allowance ( 26.4 ) 3.5 Permanent differences ( 0.3 ) ( 0.2 ) Expiration of attributes ( 1.3 ) ( 10.4 ) Stock compensation ( 1.9 ) ( 12.4 ) Uncertain tax positions — ( 7.0 ) Other ( 0.1 ) — Provision for income taxes 0.0 % 0.0 %
Summary of Activity Related to Unrecognized Tax Benefits	The following table summarizes the activity related to the Company’s unrecognized tax benefits: Year Ended 2022 2021 Gross unrecognized tax benefits at January 1 $ 893,371 $ - Additions for tax positions taken in the prior year 3,610 - Additions for tax positions taken in the current year - 893,371 Gross unrecognized tax benefits at December 31 $ 896,981 $ 893,371

Organization and Summary of S_3

Organization and Summary of Significant Accounting Policies - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2022 USD ($) Reporting_unit Segment shares	Dec. 31, 2021 USD ($) shares
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Number of operating segment | Segment	1
Cash insured amount	$ 250,000
Number of reportable unit | Reporting_unit	1
Research and development costs	$ 8,700,000	$ 8,100,000
Patent-related expenses	400,000	400,000
Clinical trial accruals	1,500,000	1,100,000
Prepaid expenses	$ 300,000	$ 400,000
Potentially dilutive outstanding securities excluded from diluted net loss per common share | shares	7,985,250	7,974,250
Minimum
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Stock option, vesting period	3 years
Minimum | Bank Certificates of Deposit
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Investments purchased maturity period	7 years
Maximum
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Stock option, vesting period	4 years
Maximum | Bank Certificates of Deposit
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Investments purchased maturity period	13 months

Revenue Recognition - Additiona

Revenue Recognition - Additional Information (Detail) - USD ($)	1 Months Ended	12 Months Ended
	Oct. 31, 2021	Dec. 31, 2022	Dec. 31, 2021	Oct. 31, 2011	Dec. 31, 2005
Kissei Pharmaceutical Co., Ltd
Revenue Recognition Milestone Method [Line Items]
Deferred revenue related to research and development services				$ 2,500,000
Revenue relating to research and development services		$ 0
Performance obligations payment refunded	$ 1,300,000
Genzyme Corporation
Revenue Recognition Milestone Method [Line Items]
Business acquisition, payments					$ 12,000,000
Recognized revenue			$ 4,000,000

Fair Value Measurements - Sched

Fair Value Measurements - Schedule of Carrying Amount and Approximate Fair Value of Financial Instruments (Details) - USD ($)	Dec. 31, 2022	Dec. 31, 2021
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying Amount	$ 18,505,493	$ 71,430,954
Money Market Funds | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying Amount	704,882	694,293
Fair Value	704,882	$ 694,293
Bank Certificates of Deposit | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying Amount	39,982,213
Fair Value	$ 39,982,213

Property and Equipment Net (Det

Property and Equipment Net (Detail) - USD ($)	Dec. 31, 2022	Dec. 31, 2021
Property, Plant and Equipment [Abstract]
Leasehold improvements	$ 13,532	$ 15,409
Furniture and equipment	121,909	124,731
Software	342,628	342,628
Property and equipment, gross, total	478,069	482,768
Less accumulated depreciation and amortization	(432,800)	(425,203)
Property and equipment, net	$ 45,269	$ 57,565

Balance Sheet Details - Additio

Balance Sheet Details - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Property Plant And Equipment Disclosure [Line Items]
Depreciation and amortization	$ 17,707	$ 26,149
Leasehold Improvements
Property Plant And Equipment Disclosure [Line Items]
Property and equipment, useful lives	5 years
Minimum
Property Plant And Equipment Disclosure [Line Items]
Property and equipment, useful lives	3 years
Maximum
Property Plant And Equipment Disclosure [Line Items]
Property and equipment, useful lives	5 years

Accrued Liabilities and Other C

Accrued Liabilities and Other Current Liabilities (Detail) - USD ($)	Dec. 31, 2022	Dec. 31, 2021
Payables and Accruals [Abstract]
Accrued compensation	$ 920,166	$ 636,481
Clinical trial accruals	1,462,354	1,076,411
Professional services fees	38,688	38,041
Other	184,100	547,270
Total accrued liabilities and other current liabilities	$ 2,605,308	$ 2,298,203

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Loss Contingencies [Line Items]
Research and development expense	$ 8,700,000	$ 8,100,000
Licensing Agreements
Loss Contingencies [Line Items]
Research and development expense	0	$ 0
Product Development
Loss Contingencies [Line Items]
Future potential milestone payments	10,000,000
Development Milestone
Loss Contingencies [Line Items]
Future potential milestone payments	16,500,000
Commercialization Milestone
Loss Contingencies [Line Items]
Future potential milestone payments	$ 16,500,000
U.S
Loss Contingencies [Line Items]
Operating lease term	5 years
Operating lease expiration date	Jan. 31, 2027
Tokyo, Japan
Loss Contingencies [Line Items]
Operating lease expiration date, month and year	2023-05
Operating lease, auto-renewal term	2 years
Operating lease, extension term	2 years
Lessee, operating lease, existence of option to extend	true

Commitments and Contingencies_2

Commitments and Contingencies - Schedule of Information Related to Right-of-Use Assets and Related Lease Liabilities (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Commitments and Contingencies Disclosure [Abstract]
Cash paid for operating lease liabilities	$ 198,035	$ 242,676
Operating lease costs	248,610	228,779
Right-of-use asset obtained in exchange for operating lease liability		870,373
Current operating lease liabilities	157,505	131,965
Non-current operating lease liabilities	$ 523,619	$ 694,674
Operating Lease, Liability, Noncurrent, Statement of Financial Position [Extensible Enumeration]	Other non-current liabilities	Other non-current liabilities
Total operating lease liabilities	$ 681,124	$ 826,639
Weighted-average remaining lease term	3 years 10 months 24 days	4 years 6 months 14 days
Weighted-average discount rate	9.80%	9.80%

Commitments and Contingencies_3

Commitments and Contingencies - Schedule of Maturities of Operating Lease Liabilities (Detail) - USD ($)	Dec. 31, 2022	Dec. 31, 2021
Leases [Abstract]
2023	$ 216,154
2024	189,170
2025	197,585
2026	206,483
2027	17,269
Total minimum payments	826,661
Less imputed interest	(145,537)
Total lease liabilities	$ 681,124	$ 826,639

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional Information (Detail) - USD ($)	1 Months Ended	12 Months Ended
	Jan. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2017	Jun. 30, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for future grant		9,934,567
Aggregate intrinsic value		$ 1,410	$ 700,000
Weighted average contractual life, options outstanding		4 years 10 months 20 days
Weighted average contractual life, options exercisable		4 years 6 months 21 days
Total intrinsic value of options outstanding		$ 0	32,840
Total intrinsic value of options exercisable		0	32,840
Fair value of options vested		$ 2,600,000	$ 4,200,000
Shares reserved, description		shares reserved automatically increase each year by a number equal to the lesser of: (i) 15,000 shares; (ii) 1% of the outstanding shares of common stock on the last day of the immediately preceding fiscal year; or (iii) such amount as determined by the Board
Employee stock purchase plan offering period		6 months
Aggregate shares issued under ESPP			1,424
Shares issued under ESPP		0
Weighted-average fair value, per option		$ 1.47	$ 3.51
2007 Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for future issuance				300,000
Percentage of employee compensation for purchase of common stock under ESPP		15%
Common stock fair market value, percentage		85%
Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock option, vesting period		3 years
Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock option, vesting period		4 years
Maximum | 2007 Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Increase in shares reserved for issuance		15,000
Increase in shares reserved for issuance as percentage of outstanding shares		1%
Performance Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of vested shares		533,700
Performance Options | Subsequent Event
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of vested shares	507,015
Number of vested shares, percentage	95%
Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unamortized compensation cost		$ 200,000
Unamortized compensation cost, vesting period		2 months 12 days
2013 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for future issuance					8,700,000
Shares available for future grant		1,949,317
2013 Plan | Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options granted expiration term		10 years
2013 Plan | Stock Option | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock option, vesting period		1 year
2013 Plan | Stock Option | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock option, vesting period		4 years
2004 Plan | Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options granted expiration term		10 years
2004 Plan | Stock Option | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock option, vesting period		1 year
2004 Plan | Stock Option | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock option, vesting period		4 years

Summary of Stock Option Activit

Summary of Stock Option Activity and Related Information (Detail) - $ / shares	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Number of Option Shares
Stock Options, Beginning Balance	7,974,250	7,401,387
Stock Options, Granted	591,700	1,315,000
Stock Options, Exercised	(3,000)	(360,955)
Stock Options, Cancelled	(577,700)	(381,182)
Stock Options, Ending Balance	7,985,250	7,974,250
Stock Options, Exercisable at December 31, 2022	7,394,381
Weighted Average Exercise Price, Beginning Balance	$ 5.81	$ 5.70
Weighted Average Exercise Price, Granted	2.28	5.82
Weighted Average Exercise Price, Exercised	2.64	2.47
Weighted Average Exercise Price, Cancelled	5.85	6.77
Weighted Average Exercise Price, Ending Balance	5.55	$ 5.81
Weighted Average Exercise Price, Exercisable at December 31, 2022	$ 5.80

Summary of Non-Vested Stock Opt

Summary of Non-Vested Stock Option Activity and Related Information (Detail) - $ / shares	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Share-Based Payment Arrangement [Abstract]
Stock Options, Non-vested, Beginning Balance	1,286,333
Stock Options, Granted	591,700	1,315,000
Stock Options, Vested	(738,134)
Stock Options, Forfeitures	(549,030)
Stock Options, Non-vested, Ending Balance	590,869	1,286,333
Weighted Average Grant-Date Fair Value, Non-vested, Beginning Balance	$ 3.54
Weighted Average Grant-Date Fair Value, Granted	1.47	$ 3.51
Weighted Average Grant-Date Fair Value, Vested	3.47
Weighted Average Grant-Date Fair Value, Forfeitures	3.58
Weighted Average Grant-Date Fair Value, Non-vested, Ending Balance	$ 1.52	$ 3.54

Weighted-Average Assumptions fo

Weighted-Average Assumptions for Stock Option and ESPP (Detail)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Employee Stock Purchase Plan
Weighted-average assumptions for stock options and ESPP
Risk-free interest rate		0.05%
Expected volatility of common stock		83.40%
Dividend yield		0%
Expected option term (in years)		6 months
Stock Option
Weighted-average assumptions for stock options and ESPP
Risk-free interest rate	3.88%	0.58%
Expected volatility of common stock	78.81%	72.41%
Dividend yield	0%	0%
Expected option term (in years)	4 years 8 months 12 days	5 years 5 months 23 days

Summary of Stock-based Compensa

Summary of Stock-based Compensation Expense (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	$ 642,522	$ 1,717,513
Research, Development and Patents
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	237,071	640,340
General and Administrative
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	$ 405,451	$ 1,077,173

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Detail) - USD ($)			12 Months Ended
	Jan. 29, 2021	Aug. 23, 2019	Dec. 31, 2022	Dec. 31, 2021
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Payments of stock issuance costs				$ 118,368
Common stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Issuance of common stock in a private transaction, net of issuance costs, shares				3,656,307
2019 at-the-market issuance sales agreement | B. Riley FBR
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Sales commission as a percentage of gross proceeds		3.50%
2019 at-the-market issuance sales agreement | Maximum | B. Riley FBR
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock purchase agreement, aggregate amount of common stock agreed to be purchased		$ 75,000,000
Private Placement
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Issuance of common stock in a private transaction, net of issuance costs, shares	3,656,307
Private Placement | Common stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share price per share	$ 5.47
Gross proceeds	$ 20,000,000
Payments of stock issuance costs	$ 100,000
ATM Agreement
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Issuance of common stock in a private transaction, net of issuance costs, shares			0	0

Common Stock Reserved for Futur

Common Stock Reserved for Future Issuance (Detail)	Dec. 31, 2022 shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for future issuance	9,934,567
2013 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for future issuance	1,949,317
Warrants | 2013 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for future issuance	1,949,317
Warrants | 2004 Plan and 2013 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for future issuance	7,985,250

Reconciliation of Loss before I

Reconciliation of Loss before Income Taxes for Domestic and Foreign Locations (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Income Tax Disclosure [Abstract]
United States	$ (14,084,240)	$ (10,145,822)
Foreign	17,979	14,138
Loss before income taxes	$ (14,066,261)	$ (10,131,684)

Reconciliation of Income Tax Ex

Reconciliation of Income Tax Expense (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Income Tax Disclosure [Abstract]
Foreign	$ (2,822)	$ (2,568)
Total current income tax expense	(2,822)	(2,568)
Total income tax expense	$ (2,822)	$ (2,568)

Components of Deferred Income T

Components of Deferred Income Taxes (Detail) - USD ($)	Dec. 31, 2022	Dec. 31, 2021
Deferred tax assets:
Net operating loss carryforwards	$ 70,142,367	$ 68,485,037
Capitalized licenses	934	30,784
Research tax credits	9,629,956	9,262,071
Stock options	1,526,644	1,601,862
Other, net	390,610	423,279
Right-of-use asset	180,938	196,059
Research and experimentation capitalization	1,795,580
Total deferred tax assets	83,667,029	79,999,092
Deferred tax liabilities
Right-of-use liability	(166,786)	(196,059)
In-process research and development	(1,343,213)	(1,343,213)
Total deferred tax liabilities	(1,509,999)	(1,539,272)
Net deferred tax assets	82,157,030	78,459,820
Valuation allowance	(82,358,822)	(78,661,612)
Net deferred tax liability	$ (201,792)	$ (201,792)

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2022 USD ($)
Income Tax [Line Items]
Net change in valuation allowance	$ 3,700,000
Unrecognized tax benefits, tax penalties and interest accrued	0
Federal
Income Tax [Line Items]
Net operating loss carryforwards	276,600,000
NOL carryforwards began to expire	$ 232,300,000
Net operating loss carryforwards, expiration year	2022
NOL carryforwards to be carried forward indefinitely	$ 44,300,000
Research tax credit carry forwards	$ 7,800,000
Research and development credits, expiration period	2024
California
Income Tax [Line Items]
Net operating loss carryforwards	$ 182,900,000
Net operating loss carryforwards, expiration year	2028
Research tax credit carry forwards	$ 2,300,000

Reconciliation of Federal Statu

Reconciliation of Federal Statutory Income Tax Rate to Effective Income Tax Rate (Detail)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Income Tax Disclosure [Abstract]
Federal statutory income tax rate	21%	21%
State income taxes, net of federal benefit	6.40%	2.70%
Tax credits	2.60%	2.80%
Change in valuation allowance	(26.40%)	3.50%
Permanent differences	(0.30%)	(0.20%)
Expiration of attributes	(1.30%)	(10.40%)
Stock compensation	(1.90%)	(12.40%)
Uncertain tax positions		(7.00%)
Other	(0.10%)
Provision for income taxes	0%	0%

Summary of Activity Related to

Summary of Activity Related to Unrecognized Tax Benefits (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Income Tax Disclosure [Abstract]
Gross unrecognized tax benefits at January 1	$ 893,371
Additions for tax positions taken in the prior year	3,610
Additions for tax positions taken in the current year		$ 893,371
Gross unrecognized tax benefits at December 31	$ 896,981	$ 893,371

Employee Savings Plan - Additio

Employee Savings Plan - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Postemployment Benefits [Abstract]
Discretionary contributions to employee savings plan	$ 75,859	$ 72,330