TRACON Pharmaceuticals (TCON) 10-Q 10 Aug 22 2022 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2022	Aug. 05, 2022
Cover [Abstract]
Entity Registrant Name	TRACON Pharmaceuticals, Inc.
Entity Central Index Key	0001394319
Document Type	10-Q
Document Period End Date	Jun. 30, 2022
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Emerging Growth Company	false
Entity Small Business	true
Entity Common Stock, Shares Outstanding		21,421,798
Document Fiscal Year Focus	2022
Document Fiscal Period Focus	Q2
Trading Symbol	TCON
Entity Shell Company	false
Entity File Number	001-36818
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	34-2037594
Title of 12(b) Security	Common Stock, par value $0.001 per share
Security Exchange Name	NASDAQ
Entity Address, Address Line One	4350 La Jolla Village Drive
Entity Address, Address Line Two	Suite 800
Entity Address, City or Town	San Diego
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	92122
City Area Code	858
Local Phone Number	550-0780
Document Quarterly Report	true
Document Transition Report	false

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Current assets:
Cash and cash equivalents	$ 13,580	$ 24,072
Prepaid and other assets	576	864
Total current assets	14,156	24,936
Property and equipment, net	50	50
Other assets	1,471	1,571
Total assets	15,677	26,557
Current liabilities:
Accounts payable and accrued expenses	11,002	10,753
Accrued compensation and related expenses	1,061	1,532
Long-term debt, current portion		1,391
Total current liabilities	12,063	13,676
Other long-term liabilities	1,072	1,167
Commitments and contingencies (Note 4)
Stockholders’ equity:
Preferred stock, $0.001 par value, authorized shares — 10,000,000 at June 30, 2022 and December 31, 2021; issued and outstanding shares — none
Common stock, $0.001 par value; authorized shares — 40,000,000 at June 30, 2022 and December 31, 2021; issued and outstanding shares — 21,421,798 and 19,445,903 at June 30, 2022 and December 31, 2021, respectively	21	19
Additional paid-in capital	226,000	219,471
Accumulated deficit	(223,479)	(207,776)
Total stockholders’ equity	2,542	11,714
Total liabilities and stockholders’ equity	$ 15,677	$ 26,557

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Jun. 30, 2022	Dec. 31, 2021
Statement Of Financial Position [Abstract]
Preferred Stock, Par or Stated Value Per Share	$ 0.001	$ 0.001
Preferred Stock, Shares Authorized	10,000,000	10,000,000
Preferred Stock, Shares Issued	0	0
Preferred Stock, Shares Outstanding	0	0
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized	40,000,000	40,000,000
Common stock, shares issued	21,421,798	19,445,903
Common stock, shares outstanding	21,421,798	19,445,903

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Income Statement [Abstract]
Collaboration revenue	$ 0	$ 346	$ 0	$ 346
Operating expenses:
Research and development	2,923	3,068	5,916	5,352
General and administrative	3,316	6,126	9,769	8,797
Total operating expenses	6,239	9,194	15,685	14,149
Loss from operations	(6,239)	(8,848)	(15,685)	(13,803)
Other income (expense):
Interest income (expense), net	8	(91)	(18)	(200)
Other income, net	1	0	0	0
Total other income (expense)	9	(91)	(18)	(200)
Net loss	$ (6,230)	$ (8,939)	$ (15,703)	$ (14,003)
Net loss per share, basic	$ (0.31)	$ (0.58)	$ (0.79)	$ (0.90)
Net loss per share, diluted	$ (0.31)	$ (0.58)	$ (0.79)	$ (0.90)
Weighted-average shares outstanding, basic	20,268,220	15,497,315	19,940,424	15,488,359
Weighted-average shares outstanding, diluted	20,268,220	15,497,315	19,940,424	15,488,359

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Deficit
Balance at Dec. 31, 2020	$ 25,072	$ 15	$ 204,166	$ (179,109)
Balance (in Shares) at Dec. 31, 2020		15,478,787
Increase (Decrease) in Shareholders' Equity
Stock-based compensation expense	343		343
Issuance of common stock under equity plans	14		14
Issuance of common stock under equity plans (in shares)		2,024
Issuance of common stock, net of offering costs	(8)		(8)
Net loss	(5,064)			(5,064)
Balance at Mar. 31, 2021	20,357	$ 15	204,515	(184,173)
Balance (in Shares) at Mar. 31, 2021		15,480,811
Balance at Dec. 31, 2020	25,072	$ 15	204,166	(179,109)
Balance (in Shares) at Dec. 31, 2020		15,478,787
Increase (Decrease) in Shareholders' Equity
Net loss	(14,003)
Balance at Jun. 30, 2021	11,915	$ 16	205,011	(193,112)
Balance (in Shares) at Jun. 30, 2021		15,501,964
Balance at Mar. 31, 2021	20,357	$ 15	204,515	(184,173)
Balance (in Shares) at Mar. 31, 2021		15,480,811
Increase (Decrease) in Shareholders' Equity
Stock-based compensation expense	417		417
Issuance of common stock under equity plans	80	$ 1	79
Issuance of common stock under equity plans (in shares)		21,153
Net loss	(8,939)			(8,939)
Balance at Jun. 30, 2021	11,915	$ 16	205,011	(193,112)
Balance (in Shares) at Jun. 30, 2021		15,501,964
Balance at Dec. 31, 2021	11,714	$ 19	219,471	(207,776)
Balance (in Shares) at Dec. 31, 2021		19,445,903
Increase (Decrease) in Shareholders' Equity
Stock-based compensation expense	548		548
Issuances of common stock, net of offering costs (in shares)		10,389
Issuance of common stock upon cashless exercise of pre-funded warrants	1	$ 1
Issuances of common stock upon cashless exercise of pre-funded warrants (in shares)		170,668
Net loss	(9,473)			(9,473)
Balance at Mar. 31, 2022	2,790	$ 20	220,019	(217,249)
Balance (in Shares) at Mar. 31, 2022		19,626,960
Balance at Dec. 31, 2021	11,714	$ 19	219,471	(207,776)
Balance (in Shares) at Dec. 31, 2021		19,445,903
Increase (Decrease) in Shareholders' Equity
Issuances of common stock upon cashless exercise of pre-funded warrants (in shares)		170,668
Net loss	(15,703)
Balance at Jun. 30, 2022	2,542	$ 21	226,000	(223,479)
Balance (in Shares) at Jun. 30, 2022		21,421,798
Balance at Mar. 31, 2022	2,790	$ 20	220,019	(217,249)
Balance (in Shares) at Mar. 31, 2022		19,626,960
Increase (Decrease) in Shareholders' Equity
Stock-based compensation expense	535		535
Issuance of common stock under equity plans	49		49
Issuance of common stock under equity plans (in shares)		23,461
Issuances of common stock upon cashless exercise of pre-funded warrants (in shares)		0
Issuance of common stock and warrants, net of offering costs	5,398	$ 1	5,397
Issuances of common stock and warrants, net of offering costs (in shares)		1,771,377
Net loss	(6,230)			(6,230)
Balance at Jun. 30, 2022	$ 2,542	$ 21	$ 226,000	$ (223,479)
Balance (in Shares) at Jun. 30, 2022		21,421,798

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021
Cash flows from operating activities
Net loss	$ (15,703)	$ (14,003)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation	1,083	760
Depreciation and amortization	9	6
Noncash interest	7	39
Amortization of debt discount	2	13
Amortization of premium/discount on short-term investments		(1)
Lease asset amortization and liability accretion, net	(12)	(19)
Equity ownership license revenue		(246)
Changes in assets and liabilities:
Prepaid expenses and other assets	288	232
Accounts payable and accrued expenses	38	4,831
Accrued compensation and related expenses	(471)	(645)
Net cash used in operating activities	(14,759)	(9,033)
Cash flows from investing activities
Purchase of property and equipment	(6)	(30)
Proceeds from the maturity of available-for-sale short-term investments		4,000
Net cash (used in) provided by investing activities	(6)	3,970
Cash flows from financing activities
Repayment of long-term debt	(1,680)	(1,400)
Proceeds from sale of common stock and pre-funded warrants, net of offering costs	5,904	(182)
Proceeds from issuance of common stock under equity plans	49	94
Net cash provided by (used in) financing activities	4,273	(1,488)
Change in cash and cash equivalents	(10,492)	(6,551)
Cash and cash equivalents at beginning of period	24,072	32,131
Cash and cash equivalents at end of period	$ 13,580	$ 25,580

Organization and Summary of Sig

Organization and Summary of Significant Accounting Policies	6 Months Ended
	Jun. 30, 2022
Organization And Accounting Policies [Abstract]
Organization and Summary of Significant Accounting Policies	1. Organization and Summary of Significant Accounting Policies Organization and Business TRACON Pharmaceuticals, Inc. (TRACON or the Company) was incorporated in the state of Delaware on October 28, 2004. TRACON is a biopharmaceutical company focused on the development and commercialization of novel targeted therapeutics for cancer, and utilizes its cost efficient, contract research organization (CRO) independent product development platform to partner with other life science companies to develop and commercialize innovative products in the United States. The unaudited condensed consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries, TRACON Pharma Limited and TRACON Pharma International Limited, which were formed in September 2015 and January 2019, respectively, and are currently inactive. All significant intercompany accounts and transactions have been eliminated. Basis of Presentation As of June 30, 2022, the Company has devoted substantially all its efforts to product development, raising capital, and building infrastructure and has not realized revenues from its planned principal operations. The Company has incurred operating losses since inception. As of June 30, 2022, the Company had an accumulated deficit of $223.5 million. The Company anticipates that it will continue to incur net losses into the foreseeable future as it continues the development and commercialization of its product candidates and works to develop additional product candidates through research and development programs. At June 30, 2022, the Company had cash and cash equivalents of $13.6 million. Based on the Company’s current business plan, management believes that there is substantial doubt as to whether existing cash and cash equivalents will be sufficient to meet its obligations as they become due within 12 months from the date the unaudited condensed consolidated financial statements are issued. The Company’s ability to execute its operating plan through 2023 and beyond depends on its ability to obtain additional funding through equity offerings, debt financings, or potential licensing and collaboration arrangements. The accompanying unaudited condensed consolidated financial statements have been prepared assuming the Company will continue as a going concern, which contemplates the realization of assets and settlement of liabilities in the normal course of business. However, the Company’s current working capital, anticipated operating expenses and net losses, and the uncertainties surrounding its ability to raise additional capital as needed, as discussed below, raise substantial doubt about its ability to continue as a going concern for a period of 12 months following the date that these unaudited condensed consolidated financial statements are issued. The unaudited condensed consolidated financial statements do not include any adjustments for the recovery and classification of assets or the amounts and classification of liabilities that might be necessary should the Company be unable to continue as a going concern. The Company plans to continue to fund its losses from operations through its existing cash and cash equivalents, as well as through future equity offerings, debt financings, other third-party funding, and potential licensing or collaboration arrangements. In addition, the Company may fund its losses from operations through the Capital on Demand TM Unaudited Interim Financial Information The unaudited condensed consolidated financial statements as of June 30, 2022, and for the three and six months ended June 30, 2022 and 2021, have been prepared in accordance with the rules and regulations of the Securities and Exchange Commission (SEC), and with accounting principles generally accepted in the United States (GAAP) applicable to interim financial statements. These unaudited condensed consolidated financial statements have been prepared on the same basis as the audited financial statements and include all adjustments, consisting of only normal recurring accruals, which in the opinion of management are necessary to present fairly the Company’s financial position as of the interim date and results of operations for the interim periods presented. Interim results are not necessarily indicative of results for a full year or future periods. These unaudited condensed consolidated financial statements should be read in conjunction with the Company’s audited financial statements for the year ended December 31, 20 2 1 , included in its Annual Report on Form 10-K filed with the SEC on March 1 5 , 202 2 . Risks and Uncertainties COVID-19, a novel strain of coronavirus (together with its variants, COVID-19), has become a global pandemic. The impact of this pandemic has been and will likely continue to be extensive in many aspects of society, which has resulted in and will likely continue to result in significant disruptions to the global economy, as well as businesses and capital markets around the world. While vaccines have become widely available in certain countries, and businesses and economies have reopened, the status of global economic recovery remains uncertain and unpredictable, and will continue to be impacted by developments in the pandemic including any subsequent waves of outbreak or new variant strains of the COVID-19 virus which may require re-closures or other preventative measures. The COVID-19 pandemic may also have long-term effects on the nature of the office environment and remote working, which may present risks for our strategy, operational, talent recruiting and retention, and workplace culture. The Company has experienced temporary closures of its offices in light of state and local orders and most of its employees continue to work remotely. In addition, the Company’s employees have not been able to conduct normal business travel, in particular as part of business development activities or in-person monitoring of clinical trial sites. Potential further impacts to the Company’s business include, but are not limited to, additional closures of its facilities or those of its vendors, continued disruptions or restrictions on its employees’ ability to travel, disruptions to or delays in ongoing clinical trials, third-party manufacturing supply and other operations, the potential diversion of healthcare resources away from the conduct of clinical trials to focus on pandemic concerns, interruptions or delays in the operations of the U.S. Food and Drug Administration or other regulatory authorities, and the Company’s ability to raise capital and conduct business development activities. Use of Estimates The Company’s unaudited condensed consolidated financial statements are prepared in accordance with accounting principles generally accepted in the United States (GAAP). The preparation of the Company’s unaudited condensed consolidated financial statements requires it to make estimates and assumptions that impact the reported amounts of assets, liabilities, revenue, and expenses. The most significant estimates in the Company’s unaudited condensed consolidated financial statements relate to expenses incurred for clinical trials. Although these estimates are based on the Company’s knowledge of current events and actions it may undertake in the future, actual results may ultimately materially differ from these estimates and assumptions. The Company is not aware of any specific event or circumstance that would require an update to its estimates, judgments and assumptions or a revision of the carrying value of the Company’s assets or liabilities as of the date of this filing. Cash and Cash Equivalents Cash and cash equivalents consist of cash and highly liquid investments with original maturities of three months or less at the date of purchase. The carrying amounts approximate fair value due to the short maturities of these investments. Cash and cash equivalents include cash in readily available checking and money market funds. Concentration of Credit Risk Financial instruments that potentially subject the Company to significant concentration of credit risk consist primarily of cash and cash equivalents. The Company maintains deposits in federally insured financial institutions in excess of federally insured limits. The Company has not experienced any losses in such accounts and management believes that the Company is not exposed to significant credit risk due to the financial position of the depository institutions in which those deposits are held. Property and Equipment Property and equipment is stated at cost and depreciated using the straight-line method over the estimated useful life of the related assets, which is generally five years. Leasehold improvements are amortized over the shorter of the lease term or estimated useful life of the related assets. Repairs and maintenance costs are charged to expense as incurred. Leases The Company determines if an arrangement contains a lease at inception. For arrangements where the Company is the lessee, operating leases are recorded as other assets, accounts payable and accrued expenses, and other long-term liabilities within the consolidated balance sheet. The Company currently does not have any finance leases. Operating lease right-of-use (ROU) assets and operating lease liabilities are recognized based on the present value of the future minimum lease payments over the lease term at commencement date. ROU assets also include any initial direct costs incurred and any lease payments made at or before the lease commencement date, less lease incentives received. The Company uses its incremental borrowing rate based on the information available at the commencement date in determining the lease liabilities as the Company’s leases generally do not provide an implicit rate. Lease terms may include options to extend or terminate when the Company is reasonably certain that the option will be exercised. Lease expense is recognized on a straight-line basis over the lease term. Revenue Recognition To date, substantially all the Company’s revenue has been derived from license agreements. The terms of these arrangements included payments to the Company for the following: non-refundable, up-front license fees; development, regulatory and commercial milestone payments; payments for manufacturing supply services the Company provides through its contract manufacturers; and royalties on net sales of licensed products. In accordance with Accounting Standards Update (ASU) No. 2014-09, Revenue from Contracts with Customers, the Company performs the following five steps in determining the appropriate amount of revenue to be recognized as it fulfills its obligations under each of these agreements: (i) identification of the contract(s) with a customer; (ii) determination of whether the promised goods or services are performance obligations including whether they are distinct in the context of the contract; (iii) measurement of the transaction price, including any constraint on variable consideration; (iv) allocation of the transaction price to the performance obligations; and (v) recognition of revenue when, or as, the Company satisfies each performance obligation. The Company only applies the five-step model to contracts when it is probable that the Company will collect the consideration it is entitled to in exchange for the goods or services transferred to the customer. Once a contract is determined to be within the scope of Accounting Standards Codification 606, Revenue from Contracts with Customers, at contract inception, the Company assesses the goods or services promised within the contract to determine those that are performance obligations and assesses whether each promised good is distinct. The Company then recognizes as revenue the amount of the transaction price that is allocated to the respective performance obligation when, or as, the performance obligation is satisfied. As part of the accounting for these arrangements, the Company develops assumptions that require judgment to determine the stand-alone selling price for each performance obligation identified in the contract. The Company uses key assumptions to determine the stand-alone selling price, which may include development timelines, reimbursement rates for personnel costs, discount rates, and probabilities of technical and regulatory success . Licenses of intellectual property: If the license to the Company’s intellectual property is determined to be distinct from the other performance obligations identified in the arrangement, the Company recognizes revenues allocated to the license when the license is transferred to the customer and the customer is able to use and benefit from the license. For licenses that are bundled with other promised goods or services, the Company utilizes judgment to assess the nature of the combined performance obligation to determine whether the combined performance obligation is satisfied over time or at a point in time and, if over time, the appropriate method of measuring progress for purposes of recognizing revenue. The Company evaluates the measure of progress each reporting period and, if necessary, adjusts the measure of performance and related revenue recognition. Milestone Payments: At the inception of each arrangement that includes development, commercialization, and regulatory milestone payments, the Company evaluates whether the achievement of the milestones is considered probable and estimates the amount to be included in the transaction price using the most likely amount method. Performance milestone payments represent a form of variable consideration. If it is probable that a significant revenue reversal would not occur, the associated milestone value is included in the transaction price. Achievement of milestones that are not within the control of the Company or the licensee, such as regulatory approvals, are not considered probable until the approvals are achieved. The transaction price is then allocated to each performance obligation on a relative stand-alone selling price basis and the Company recognizes revenue as or when the performance obligations under the contract are satisfied. At the end of each subsequent reporting period, the Company re-evaluates the probability of achieving such milestones and any related constraint, and if necessary, adjusts its estimate of the overall transaction price. Any such adjustments are recorded on a cumulative catch-up basis, which would affect revenues and earnings in the period of adjustment. Manufacturing Supply Services: Arrangements that include a promise for future supply of drug substance or drug product for either clinical development or commercial supply at the customer’s discretion are generally considered options. The Company assesses if these options provide a material right to the licensee and if so, they are accounted for as separate performance obligations at the outset of the arrangement. Royalties: For arrangements that include sales-based royalties, including milestone payments based on the level of sales, and the license is deemed to be the predominant item to which the royalties relate, the Company recognizes revenue at the later of (i) when the related sales occur or (ii) when the performance obligation to which some or all of the royalty has been allocated has been satisfied (or partially satisfied). To date, the Company has not recognized any royalty revenue resulting from any of its out-licensing arrangements. The Company receives payments from its collaborators based on billing schedules established in each contract. Up-front and other payments may require deferral of revenue recognition to a future period until the Company performs its obligations under its collaboration arrangements. Amounts are recorded as accounts receivable when the Company’s right to consideration is unconditional. The Company does not assess whether a contract has a significant financing component if the expectation at contract inception is such that the period between payment by the customer and the transfer of the promised goods or services to the customer will be one year or less. Clinical Trial Expense Accruals As part of the process of preparing the Company’s unaudited condensed consolidated financial statements, the Company is required to estimate expenses resulting from its obligations under contracts with vendors, clinical sites, and consultants in connection with conducting clinical trials. The financial terms of these contracts vary and may result in payment flows that do not match the periods over which materials or services are provided under such contracts. The Company’s objective is to reflect the appropriate trial expenses in its unaudited condensed consolidated financial statements by recording those expenses in the period in which services are performed and efforts are expended. The Company accounts for these expenses according to the progress of the clinical trial as measured by patient progression and the timing of various aspects of the trial. The Company determines accrual estimates through discussion with the clinical sites and applicable personnel and outside service providers as to the progress or state of consummation of trials. During a clinical trial, the Company adjusts the clinical expense recognition if actual results differ from its estimates. The Company makes estimates of accrued expenses as of each balance sheet date based on the facts and circumstances known at that time. The Company’s clinical trial accruals are dependent upon accurate reporting by clinical sites and other third-party vendors. Although the Company does not expect its estimates to differ materially from amounts actually incurred, its understanding of the status and timing of services performed relative to the actual status and timing of services performed may vary and may result in reporting amounts that are too high or too low for any particular period. For the three and six months ended June 30, 2022 and 2021, there were no material adjustments to the Company’s prior period estimates of accrued expenses for clinical trials. Research and Development Costs Research and development costs, including license fees, are expensed as incurred. Comprehensive Loss Comprehensive loss is defined as a change in equity during a period from transactions and other events and circumstances from non-owner sources. Net loss and comprehensive loss were the same for all periods presented. Net Loss Per Share Basic net loss per share is calculated by dividing the net loss by the weighted-average shares of common stock outstanding for the period, without consideration for common stock equivalents and adjusted for the weighted average number of shares of common stock outstanding that are subject to repurchase. Diluted net loss per share is calculated by dividing the net loss by the weighted-average number of common stock equivalents outstanding for the period determined using the treasury-stock method. For all periods presented, there is no difference in the number of shares used to calculate basic and diluted shares outstanding due to the Company’s net loss position. Potentially dilutive securities not included in the calculation of diluted net loss per share because to do so would be anti-dilutive are as follows (in common stock equivalent shares): June 30, 2022 2021 Warrants to purchase common stock 6,837,032 4,810,409 Common stock options 2,246,310 1,260,367 ESPP shares 1,040 1,244 9,084,382 6,072,020

Investments, Cash Equivalents a

Investments, Cash Equivalents and Fair Value Measurements	6 Months Ended
	Jun. 30, 2022
Fair Value Disclosures [Abstract]
Investments, Cash Equivalents and Fair Value Measurements	2. Investments, Cash Equivalents and Fair Value Measurements At June 30, 2022 and December 31, 2021, the Company had no short-term investments. The Company classifies all investments as available-for-sale securities, as the sale of such investments may be required prior to maturity to implement management strategies. These investments are carried at amortized cost which approximates fair value. A decline in the market value of any short-term investment below cost that is determined to be other-than-temporary will result in a revaluation of its carrying amount to fair value. The impairment is charged to earnings and a new cost basis for the security is established. No such impairment charges were recorded for any period presented. Realized gains and losses from the sale of short-term investments, if any, are determined on a specific identification basis. Realized gains and losses and declines in value judged to be other-than-temporary, if any, on available-for-sale securities are included in other income or expense on the consolidated statements of operations. Realized and unrealized gains and losses during the periods presented were immaterial. Premiums and discounts are amortized or accreted over the life of the related security as an adjustment to yield using the straight-line method and are included in interest income on the consolidated statements of operations. Interest and dividends on securities classified as available-for-sale are included in interest income on the consolidated statements of operations. The carrying amounts of cash and cash equivalents, prepaid and other assets, accounts payable and accrued liabilities are considered to be representative of their respective fair values because of the short-term nature of those instruments. Based on the borrowing rates currently available to the Company for loans with similar terms, which is considered a Level 2 input, the Company believes that the fair value of long-term debt approximates its carrying value. The accounting guidance defines fair value, establishes a consistent framework for measuring fair value and expands disclosure for each major asset and liability category measured at fair value on either a recurring or nonrecurring basis. Fair value is defined as an exit price, representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. 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, the accounting guidance establishes a three-tier fair value hierarchy, 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, other than the quoted prices in active markets that are observable either directly or indirectly. Level 3: Unobservable inputs in which there is little or no market data, which require the reporting entity to develop its own assumptions. Assets and liabilities are classified based on the lowest level of input that is significant to the fair value measurements. None of the Company’s non-financial assets or liabilities are recorded at fair value on a non-recurring basis. No transfers between levels have occurred during the periods presented. Cash equivalents, which are classified as equity securities, and equity securities consisted of the following (in thousands): June 30, 2022 December 31, 2021 Cost Unrealized Gain Unrealized (Loss) Estimated Fair Value Cost Unrealized Gain Unrealized (Loss) Estimated Fair Value Money market funds included in cash equivalents $ — $ — $ — $ — $ 5,003 $ — $ — $ 5,003 Equity securities included in other assets (1) 246 — — 246 246 — — 246 $ 246 $ — $ — $ 246 $ 5,249 $ — $ — $ 5,249 (1) The fair values of the Company’s assets and liabilities, which are measured at fair value on a recurring basis, were determined using the following inputs (in thousands): Fair Value Measurements at Reporting Date Using Quoted Prices in Significant Active Markets Other Significant for Identical Observable Unobservable Assets Inputs Inputs Total (Level 1) (Level 2) (Level 3) At December 31, 2021 Money market funds $ 5,003 $ — $ 5,003 $ —

Long-Term Debt

Long-Term Debt	6 Months Ended
	Jun. 30, 2022
Debt Disclosure [Abstract]
Long-Term Debt	3 . Long-Term Debt In May 2018, the Company entered into a third amendment to its Amended and Restated Loan and Security Agreement with Silicon Valley Bank (the 2018 Amended SVB Loan) under which the Company borrowed $7.0 million, all of which was immediately used to repay the Company’s then existing loan with SVB (the 2017 Amended SVB Loan). The 2018 Amended SVB Loan matured in June 2022 At June 30, 2022, the Company had the following exercisable outstanding warrants for the purchase of common stock issued in connection with the Company’s loan agreements with SVB: Expiration Number of shares Exercise price November 14, 2023 through June 4, 2024 3,874 $ 77.40 January 25, 2024 4,669 $ 51.40 May 3, 2025 5,363 $ 26.10 13,906

Commitments and Contingencies

Commitments and Contingencies	6 Months Ended
	Jun. 30, 2022
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	4 . Commitments and Contingencies License Agreements The Company has entered into various license agreements pursuant to which the Company acquired licenses to certain intellectual property. The agreements generally required an upfront license fee and, in some cases, reimbursement of patent costs. Additionally, under each agreement, the Company may be required to pay annual maintenance fees, royalties, milestone payments and sublicensing fees. Each license agreement is generally cancelable by the Company, given appropriate prior written notice. At June 30, 2022, potential future milestone payments under these agreements totaled an aggregate of $9.6 million.

Stockholders' Equity

Stockholders' Equity	6 Months Ended
	Jun. 30, 2022
Stockholders Equity Note [Abstract]
Stockholders' Equity	5. Stockholders’ Equity Sale of Common Stock and Pre-Funded Warrants In June 2022, the Company issued and sold 841,989 shares of its common stock at a purchase price of $1.32 per share and pre-funded warrants to purchase 2,205,018 shares of its common stock at a purchase price of $1.31 per share of underlying common stock with an exercise price of $0.01 per share of underlying common stock (the 2022 Pre-Funded Warrants) for net proceeds of approximately $3.9 million in a registered direct offering (the Offering) with an accredited institutional healthcare-focused fund. In accordance with their terms, the 2022 Pre-Funded Warrants may not be exercised if the holder’s ownership of the Company’s common stock would exceed 19.99% of the shares of the Company’s common stock outstanding immediately after giving effect to such exercise. The 2022 Pre-Funded Warrants were recorded as a component of stockholders’ equity within additional paid-in capital on the consolidated balance sheets. In connection with the Offering, the Company amended two existing pre-funded warrants to purchase shares of the Company’s common stock held by the same institutional healthcare-focused fund to extend the exercise periods and to permit exercise in excess of a similar 19.99% limit following approval of the Company’s stockholders of such exercise. At-The-Market Issuance Sales Agreement In December 2020, as amended in March 2022, the Company entered into a Capital on Demand TM Equity Plan Activity During the t hree and six months ended June 30, 2022, the Company issued shares of common stock upon the exercise of outstanding stock options, 0 shares of common stock upon the vesting of restricted stock units, and 23,461 shares of common stock in connection with the employee stock purchase plan (the ESPP). During the year ended December 31, 2021, the Company issued 3,727 shares of common stock upon the exercise of outstanding stock options, 0 shares of common stock upon the vesting of restricted stock units, and 36,687 shares of common stock in connection with the ESPP. Common Stock Warrants As of June 30, 2022 , the Company had the following outstanding warrants for the purchase of common stock: Expiration Number of shares Exercise price November 14, 2023 through June 4, 2024 3,874 $ 77.40 January 25, 2024 4,669 $ 51.40 March 27, 2024 1,369,602 $ 27.00 May 3, 2025 5,363 $ 26.10 August 27, 2030 1,889,513 $ 0.01 August 31, 2030 1,358,993 $ 0.01 June 21, 2032 2,205,018 $ 0.01 6,837,032 During the three and six months ended June 30, 2022, the Company issued 0 and 170,668 shares of its common stock upon the cashless exercise of pre-funded warrants to purchase 176,554 shares of common stock, respectively. During the year ended December 31, 2021, no warrants were exercised. Stock-Based Compensation Expense The weighted-average assumptions used in the Black-Scholes option pricing model to determine the fair value of the employee stock option grants were as follows: Three Months Ended Six Months Ended June 30, June 30, 2022 2021 2022 2021 Risk-free interest rate 3.6% 1.0% 1.9% 0.8% Expected volatility 93% 90% 90% 90% Expected term (in years) 5.5 6.0 6.2 6.2 Expected dividend yield —% —% —% —% Stock compensation expense for the ESPP was immaterial for the three and six months ended June 30, 2022 and 2021. The allocation of stock-based compensation expense was as follows (in thousands): Three Months Ended Six Months Ended June 30, June 30, 2022 2021 2022 2021 Research and development $ 209 $ 145 $ 409 $ 271 General and administrative 326 272 674 489 $ 535 $ 417 $ 1,083 $ 760

Organization and Summary of S_2

Organization and Summary of Significant Accounting Policies (Policies)	6 Months Ended
	Jun. 30, 2022
Organization And Accounting Policies [Abstract]
Organization and Business	Organization and Business TRACON Pharmaceuticals, Inc. (TRACON or the Company) was incorporated in the state of Delaware on October 28, 2004. TRACON is a biopharmaceutical company focused on the development and commercialization of novel targeted therapeutics for cancer, and utilizes its cost efficient, contract research organization (CRO) independent product development platform to partner with other life science companies to develop and commercialize innovative products in the United States. The unaudited condensed consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries, TRACON Pharma Limited and TRACON Pharma International Limited, which were formed in September 2015 and January 2019, respectively, and are currently inactive. All significant intercompany accounts and transactions have been eliminated.
Basis of Presentation	Basis of Presentation As of June 30, 2022, the Company has devoted substantially all its efforts to product development, raising capital, and building infrastructure and has not realized revenues from its planned principal operations. The Company has incurred operating losses since inception. As of June 30, 2022, the Company had an accumulated deficit of $223.5 million. The Company anticipates that it will continue to incur net losses into the foreseeable future as it continues the development and commercialization of its product candidates and works to develop additional product candidates through research and development programs. At June 30, 2022, the Company had cash and cash equivalents of $13.6 million. Based on the Company’s current business plan, management believes that there is substantial doubt as to whether existing cash and cash equivalents will be sufficient to meet its obligations as they become due within 12 months from the date the unaudited condensed consolidated financial statements are issued. The Company’s ability to execute its operating plan through 2023 and beyond depends on its ability to obtain additional funding through equity offerings, debt financings, or potential licensing and collaboration arrangements. The accompanying unaudited condensed consolidated financial statements have been prepared assuming the Company will continue as a going concern, which contemplates the realization of assets and settlement of liabilities in the normal course of business. However, the Company’s current working capital, anticipated operating expenses and net losses, and the uncertainties surrounding its ability to raise additional capital as needed, as discussed below, raise substantial doubt about its ability to continue as a going concern for a period of 12 months following the date that these unaudited condensed consolidated financial statements are issued. The unaudited condensed consolidated financial statements do not include any adjustments for the recovery and classification of assets or the amounts and classification of liabilities that might be necessary should the Company be unable to continue as a going concern. The Company plans to continue to fund its losses from operations through its existing cash and cash equivalents, as well as through future equity offerings, debt financings, other third-party funding, and potential licensing or collaboration arrangements. In addition, the Company may fund its losses from operations through the Capital on Demand TM Unaudited Interim Financial Information The unaudited condensed consolidated financial statements as of June 30, 2022, and for the three and six months ended June 30, 2022 and 2021, have been prepared in accordance with the rules and regulations of the Securities and Exchange Commission (SEC), and with accounting principles generally accepted in the United States (GAAP) applicable to interim financial statements. These unaudited condensed consolidated financial statements have been prepared on the same basis as the audited financial statements and include all adjustments, consisting of only normal recurring accruals, which in the opinion of management are necessary to present fairly the Company’s financial position as of the interim date and results of operations for the interim periods presented. Interim results are not necessarily indicative of results for a full year or future periods. These unaudited condensed consolidated financial statements should be read in conjunction with the Company’s audited financial statements for the year ended December 31, 20 2 1 , included in its Annual Report on Form 10-K filed with the SEC on March 1 5 , 202 2 .
Risks And Uncertainties	Risks and Uncertainties COVID-19, a novel strain of coronavirus (together with its variants, COVID-19), has become a global pandemic. The impact of this pandemic has been and will likely continue to be extensive in many aspects of society, which has resulted in and will likely continue to result in significant disruptions to the global economy, as well as businesses and capital markets around the world. While vaccines have become widely available in certain countries, and businesses and economies have reopened, the status of global economic recovery remains uncertain and unpredictable, and will continue to be impacted by developments in the pandemic including any subsequent waves of outbreak or new variant strains of the COVID-19 virus which may require re-closures or other preventative measures. The COVID-19 pandemic may also have long-term effects on the nature of the office environment and remote working, which may present risks for our strategy, operational, talent recruiting and retention, and workplace culture. The Company has experienced temporary closures of its offices in light of state and local orders and most of its employees continue to work remotely. In addition, the Company’s employees have not been able to conduct normal business travel, in particular as part of business development activities or in-person monitoring of clinical trial sites. Potential further impacts to the Company’s business include, but are not limited to, additional closures of its facilities or those of its vendors, continued disruptions or restrictions on its employees’ ability to travel, disruptions to or delays in ongoing clinical trials, third-party manufacturing supply and other operations, the potential diversion of healthcare resources away from the conduct of clinical trials to focus on pandemic concerns, interruptions or delays in the operations of the U.S. Food and Drug Administration or other regulatory authorities, and the Company’s ability to raise capital and conduct business development activities.
Use of Estimates	Use of Estimates The Company’s unaudited condensed consolidated financial statements are prepared in accordance with accounting principles generally accepted in the United States (GAAP). The preparation of the Company’s unaudited condensed consolidated financial statements requires it to make estimates and assumptions that impact the reported amounts of assets, liabilities, revenue, and expenses. The most significant estimates in the Company’s unaudited condensed consolidated financial statements relate to expenses incurred for clinical trials. Although these estimates are based on the Company’s knowledge of current events and actions it may undertake in the future, actual results may ultimately materially differ from these estimates and assumptions. The Company is not aware of any specific event or circumstance that would require an update to its estimates, judgments and assumptions or a revision of the carrying value of the Company’s assets or liabilities as of the date of this filing.
Cash and Cash Equivalents	Cash and Cash Equivalents Cash and cash equivalents consist of cash and highly liquid investments with original maturities of three months or less at the date of purchase. The carrying amounts approximate fair value due to the short maturities of these investments. Cash and cash equivalents include cash in readily available checking and money market funds.
Concentration of Credit Risk	Concentration of Credit Risk Financial instruments that potentially subject the Company to significant concentration of credit risk consist primarily of cash and cash equivalents. The Company maintains deposits in federally insured financial institutions in excess of federally insured limits. The Company has not experienced any losses in such accounts and management believes that the Company is not exposed to significant credit risk due to the financial position of the depository institutions in which those deposits are held.
Property and Equipment	Property and Equipment Property and equipment is stated at cost and depreciated using the straight-line method over the estimated useful life of the related assets, which is generally five years. Leasehold improvements are amortized over the shorter of the lease term or estimated useful life of the related assets. Repairs and maintenance costs are charged to expense as incurred.
Leases	Leases The Company determines if an arrangement contains a lease at inception. For arrangements where the Company is the lessee, operating leases are recorded as other assets, accounts payable and accrued expenses, and other long-term liabilities within the consolidated balance sheet. The Company currently does not have any finance leases. Operating lease right-of-use (ROU) assets and operating lease liabilities are recognized based on the present value of the future minimum lease payments over the lease term at commencement date. ROU assets also include any initial direct costs incurred and any lease payments made at or before the lease commencement date, less lease incentives received. The Company uses its incremental borrowing rate based on the information available at the commencement date in determining the lease liabilities as the Company’s leases generally do not provide an implicit rate. Lease terms may include options to extend or terminate when the Company is reasonably certain that the option will be exercised. Lease expense is recognized on a straight-line basis over the lease term.
Revenue Recognition	Revenue Recognition To date, substantially all the Company’s revenue has been derived from license agreements. The terms of these arrangements included payments to the Company for the following: non-refundable, up-front license fees; development, regulatory and commercial milestone payments; payments for manufacturing supply services the Company provides through its contract manufacturers; and royalties on net sales of licensed products. In accordance with Accounting Standards Update (ASU) No. 2014-09, Revenue from Contracts with Customers, the Company performs the following five steps in determining the appropriate amount of revenue to be recognized as it fulfills its obligations under each of these agreements: (i) identification of the contract(s) with a customer; (ii) determination of whether the promised goods or services are performance obligations including whether they are distinct in the context of the contract; (iii) measurement of the transaction price, including any constraint on variable consideration; (iv) allocation of the transaction price to the performance obligations; and (v) recognition of revenue when, or as, the Company satisfies each performance obligation. The Company only applies the five-step model to contracts when it is probable that the Company will collect the consideration it is entitled to in exchange for the goods or services transferred to the customer. Once a contract is determined to be within the scope of Accounting Standards Codification 606, Revenue from Contracts with Customers, at contract inception, the Company assesses the goods or services promised within the contract to determine those that are performance obligations and assesses whether each promised good is distinct. The Company then recognizes as revenue the amount of the transaction price that is allocated to the respective performance obligation when, or as, the performance obligation is satisfied. As part of the accounting for these arrangements, the Company develops assumptions that require judgment to determine the stand-alone selling price for each performance obligation identified in the contract. The Company uses key assumptions to determine the stand-alone selling price, which may include development timelines, reimbursement rates for personnel costs, discount rates, and probabilities of technical and regulatory success . Licenses of intellectual property: If the license to the Company’s intellectual property is determined to be distinct from the other performance obligations identified in the arrangement, the Company recognizes revenues allocated to the license when the license is transferred to the customer and the customer is able to use and benefit from the license. For licenses that are bundled with other promised goods or services, the Company utilizes judgment to assess the nature of the combined performance obligation to determine whether the combined performance obligation is satisfied over time or at a point in time and, if over time, the appropriate method of measuring progress for purposes of recognizing revenue. The Company evaluates the measure of progress each reporting period and, if necessary, adjusts the measure of performance and related revenue recognition. Milestone Payments: At the inception of each arrangement that includes development, commercialization, and regulatory milestone payments, the Company evaluates whether the achievement of the milestones is considered probable and estimates the amount to be included in the transaction price using the most likely amount method. Performance milestone payments represent a form of variable consideration. If it is probable that a significant revenue reversal would not occur, the associated milestone value is included in the transaction price. Achievement of milestones that are not within the control of the Company or the licensee, such as regulatory approvals, are not considered probable until the approvals are achieved. The transaction price is then allocated to each performance obligation on a relative stand-alone selling price basis and the Company recognizes revenue as or when the performance obligations under the contract are satisfied. At the end of each subsequent reporting period, the Company re-evaluates the probability of achieving such milestones and any related constraint, and if necessary, adjusts its estimate of the overall transaction price. Any such adjustments are recorded on a cumulative catch-up basis, which would affect revenues and earnings in the period of adjustment. Manufacturing Supply Services: Arrangements that include a promise for future supply of drug substance or drug product for either clinical development or commercial supply at the customer’s discretion are generally considered options. The Company assesses if these options provide a material right to the licensee and if so, they are accounted for as separate performance obligations at the outset of the arrangement. Royalties: For arrangements that include sales-based royalties, including milestone payments based on the level of sales, and the license is deemed to be the predominant item to which the royalties relate, the Company recognizes revenue at the later of (i) when the related sales occur or (ii) when the performance obligation to which some or all of the royalty has been allocated has been satisfied (or partially satisfied). To date, the Company has not recognized any royalty revenue resulting from any of its out-licensing arrangements. The Company receives payments from its collaborators based on billing schedules established in each contract. Up-front and other payments may require deferral of revenue recognition to a future period until the Company performs its obligations under its collaboration arrangements. Amounts are recorded as accounts receivable when the Company’s right to consideration is unconditional. The Company does not assess whether a contract has a significant financing component if the expectation at contract inception is such that the period between payment by the customer and the transfer of the promised goods or services to the customer will be one year or less.
Clinical Trial Expense Accruals	Clinical Trial Expense Accruals As part of the process of preparing the Company’s unaudited condensed consolidated financial statements, the Company is required to estimate expenses resulting from its obligations under contracts with vendors, clinical sites, and consultants in connection with conducting clinical trials. The financial terms of these contracts vary and may result in payment flows that do not match the periods over which materials or services are provided under such contracts. The Company’s objective is to reflect the appropriate trial expenses in its unaudited condensed consolidated financial statements by recording those expenses in the period in which services are performed and efforts are expended. The Company accounts for these expenses according to the progress of the clinical trial as measured by patient progression and the timing of various aspects of the trial. The Company determines accrual estimates through discussion with the clinical sites and applicable personnel and outside service providers as to the progress or state of consummation of trials. During a clinical trial, the Company adjusts the clinical expense recognition if actual results differ from its estimates. The Company makes estimates of accrued expenses as of each balance sheet date based on the facts and circumstances known at that time. The Company’s clinical trial accruals are dependent upon accurate reporting by clinical sites and other third-party vendors. Although the Company does not expect its estimates to differ materially from amounts actually incurred, its understanding of the status and timing of services performed relative to the actual status and timing of services performed may vary and may result in reporting amounts that are too high or too low for any particular period. For the three and six months ended June 30, 2022 and 2021, there were no material adjustments to the Company’s prior period estimates of accrued expenses for clinical trials.
Research and Development Costs	Research and Development Costs Research and development costs, including license fees, are expensed as incurred.
Comprehensive Loss	Comprehensive Loss Comprehensive loss is defined as a change in equity during a period from transactions and other events and circumstances from non-owner sources. Net loss and comprehensive loss were the same for all periods presented.
Net Loss Per Share	Net Loss Per Share Basic net loss per share is calculated by dividing the net loss by the weighted-average shares of common stock outstanding for the period, without consideration for common stock equivalents and adjusted for the weighted average number of shares of common stock outstanding that are subject to repurchase. Diluted net loss per share is calculated by dividing the net loss by the weighted-average number of common stock equivalents outstanding for the period determined using the treasury-stock method. For all periods presented, there is no difference in the number of shares used to calculate basic and diluted shares outstanding due to the Company’s net loss position. Potentially dilutive securities not included in the calculation of diluted net loss per share because to do so would be anti-dilutive are as follows (in common stock equivalent shares): June 30, 2022 2021 Warrants to purchase common stock 6,837,032 4,810,409 Common stock options 2,246,310 1,260,367 ESPP shares 1,040 1,244 9,084,382 6,072,020

Organization and Summary of S_3

Organization and Summary of Significant Accounting Policies (Tables)	6 Months Ended
	Jun. 30, 2022
Organization And Accounting Policies [Abstract]
Schedule of potentially dilutive securities not included in the calculation of diluted net loss per share	Potentially dilutive securities not included in the calculation of diluted net loss per share because to do so would be anti-dilutive are as follows (in common stock equivalent shares): June 30, 2022 2021 Warrants to purchase common stock 6,837,032 4,810,409 Common stock options 2,246,310 1,260,367 ESPP shares 1,040 1,244 9,084,382 6,072,020

Investments, Cash Equivalents_2

Investments, Cash Equivalents and Fair Value Measurements (Tables)	6 Months Ended
	Jun. 30, 2022
Fair Value Disclosures [Abstract]
Schedule of Available-for-sale Securities and Equity Securities	Cash equivalents, which are classified as equity securities, and equity securities consisted of the following (in thousands): June 30, 2022 December 31, 2021 Cost Unrealized Gain Unrealized (Loss) Estimated Fair Value Cost Unrealized Gain Unrealized (Loss) Estimated Fair Value Money market funds included in cash equivalents $ — $ — $ — $ — $ 5,003 $ — $ — $ 5,003 Equity securities included in other assets (1) 246 — — 246 246 — — 246 $ 246 $ — $ — $ 246 $ 5,249 $ — $ — $ 5,249 (1)
Schedule of assets and liabilities measured at fair value on a recurring basis	The fair values of the Company’s assets and liabilities, which are measured at fair value on a recurring basis, were determined using the following inputs (in thousands): Fair Value Measurements at Reporting Date Using Quoted Prices in Significant Active Markets Other Significant for Identical Observable Unobservable Assets Inputs Inputs Total (Level 1) (Level 2) (Level 3) At December 31, 2021 Money market funds $ 5,003 $ — $ 5,003 $ —

Long-Term Debt (Tables)

Long-Term Debt (Tables)	6 Months Ended
	Jun. 30, 2022
Debt Disclosure [Abstract]
Schedule of exercisable outstanding warrants for purchase of common stock issued	At June 30, 2022, the Company had the following exercisable outstanding warrants for the purchase of common stock issued in connection with the Company’s loan agreements with SVB: Expiration Number of shares Exercise price November 14, 2023 through June 4, 2024 3,874 $ 77.40 January 25, 2024 4,669 $ 51.40 May 3, 2025 5,363 $ 26.10 13,906 As of June 30, 2022 , the Company had the following outstanding warrants for the purchase of common stock: Expiration Number of shares Exercise price November 14, 2023 through June 4, 2024 3,874 $ 77.40 January 25, 2024 4,669 $ 51.40 March 27, 2024 1,369,602 $ 27.00 May 3, 2025 5,363 $ 26.10 August 27, 2030 1,889,513 $ 0.01 August 31, 2030 1,358,993 $ 0.01 June 21, 2032 2,205,018 $ 0.01 6,837,032

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	6 Months Ended
	Jun. 30, 2022
Stockholders Equity Note [Abstract]
Schedule of exercisable outstanding warrants for purchase of common stock issued	At June 30, 2022, the Company had the following exercisable outstanding warrants for the purchase of common stock issued in connection with the Company’s loan agreements with SVB: Expiration Number of shares Exercise price November 14, 2023 through June 4, 2024 3,874 $ 77.40 January 25, 2024 4,669 $ 51.40 May 3, 2025 5,363 $ 26.10 13,906 As of June 30, 2022 , the Company had the following outstanding warrants for the purchase of common stock: Expiration Number of shares Exercise price November 14, 2023 through June 4, 2024 3,874 $ 77.40 January 25, 2024 4,669 $ 51.40 March 27, 2024 1,369,602 $ 27.00 May 3, 2025 5,363 $ 26.10 August 27, 2030 1,889,513 $ 0.01 August 31, 2030 1,358,993 $ 0.01 June 21, 2032 2,205,018 $ 0.01 6,837,032
Summary of weighted-average assumptions used Black-Scholes option pricing model to determine the fair value	The weighted-average assumptions used in the Black-Scholes option pricing model to determine the fair value of the employee stock option grants were as follows: Three Months Ended Six Months Ended June 30, June 30, 2022 2021 2022 2021 Risk-free interest rate 3.6% 1.0% 1.9% 0.8% Expected volatility 93% 90% 90% 90% Expected term (in years) 5.5 6.0 6.2 6.2 Expected dividend yield —% —% —% —%
Summary of allocation of stock-based compensation expense	The allocation of stock-based compensation expense was as follows (in thousands): Three Months Ended Six Months Ended June 30, June 30, 2022 2021 2022 2021 Research and development $ 209 $ 145 $ 409 $ 271 General and administrative 326 272 674 489 $ 535 $ 417 $ 1,083 $ 760

Organization and Summary of S_4

Organization and Summary of Significant Accounting Policies - Additional Information (Details) - USD ($)	6 Months Ended
	Jun. 30, 2022	Dec. 31, 2021
Basis of Presentation
Accumulated deficit	$ 223,479,000	$ 207,776,000
Cash, cash equivalents and short-term investments	$ 13,600,000
Property and Equipment
Estimated useful life	5 years
Jones Trading Institutional Services LLC | Capital on Demand Sales Agreement | Common Stock
Basis of Presentation
Maximum aggregate value of stock to be sold	$ 50,000,000
Remaining amount available under the Sales Agreement	$ 48,000,000

Organization and Summary of S_5

Organization and Summary of Significant Accounting Policies - Schedule of Potentially Dilutive Securities Not Included in the Calculation of Diluted Net Loss Per Share (Details) - shares	6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021
Antidilutive securities
Antidilutive securities	9,084,382	6,072,020
Warrants to Purchase Common Stock
Antidilutive securities
Antidilutive securities	6,837,032	4,810,409
Common Stock Options
Antidilutive securities
Antidilutive securities	2,246,310	1,260,367
ESPP Shares
Antidilutive securities
Antidilutive securities	1,040	1,244

Investments, Cash Equivalents_3

Investments, Cash Equivalents and Fair Value Measurements - Additional Information (Details) - USD ($)	Jun. 30, 2022	Dec. 31, 2021
Fair Value Disclosures [Abstract]
Short-term investments	$ 0	$ 0
Amount of transfers between levels	$ 0	$ 0

Investments, Cash Equivalents_4

Investments, Cash Equivalents and Fair Value Measurements - Schedule of Available-for-sale Securities and Equity Securities (Details) - USD ($) $ in Thousands		Jun. 30, 2022	Dec. 31, 2021
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cost		$ 246	$ 5,249
Estimated Fair Value		246	5,249
Money market funds included in cash equivalents
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cost			5,003
Estimated Fair Value			5,003
Equity securities included in other assets
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cost	[1]	246	246
Estimated Fair Value	[1]	$ 246	$ 246
[1]The Company’s equity securities included in other assets consisted of its investment in a privately held company. The Company recognizes its private company equity securities at cost minus impairments, plus or minus changes resulting from observable price changes in orderly transactions for the identical or similar investment of the same issuer. No such impairments or changes were noted for any period presented

Investments, Cash Equivalents_5

Investments, Cash Equivalents and Fair Value Measurements - Schedule of Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) - Recurring - Money market funds $ in Thousands	Dec. 31, 2021 USD ($)
Assets:
Fair value, assets	$ 5,003
Level 2
Assets:
Fair value, assets	$ 5,003

Long-Term Debt - Additional Inf

Long-Term Debt - Additional Information (Details) - Silicon Valley Bank - USD ($)	1 Months Ended	6 Months Ended
	May 31, 2018	Jun. 30, 2022
2018 SVB Loan
Debt Instrument [Line Items]
Proceeds From Issuance Of Long Term Debt	$ 7,000,000
Final payment on payoff		$ 300,000
Deferral Agreement
Debt Instrument [Line Items]
Maturity date		Jun. 30, 2022

Long-Term Debt - Schedule of Ex

Long-Term Debt - Schedule of Exercisable Outstanding Warrants for Purchase of Common Stock Issued (Details)	Jun. 30, 2022 $ / shares shares
Debt Instrument [Line Items]
Warrants issued	6,837,032
Silicon Valley Bank
Debt Instrument [Line Items]
Warrants issued	13,906
Silicon Valley Bank | November 14, 2023 Through June 4, 2024
Debt Instrument [Line Items]
Warrants issued	3,874
Exercise price (per share) | $ / shares	$ 77.40
Silicon Valley Bank | January 25, 2024
Debt Instrument [Line Items]
Warrants issued	4,669
Exercise price (per share) | $ / shares	$ 51.40
Silicon Valley Bank | May 3, 2025
Debt Instrument [Line Items]
Warrants issued	5,363
Exercise price (per share) | $ / shares	$ 26.10

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Details) $ in Millions	Jun. 30, 2022 USD ($)
Research and development arrangement
Commitments and Contingencies
Potential milestone payable	$ 9.6

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Details)	1 Months Ended		3 Months Ended		6 Months Ended	12 Months Ended
	Jun. 30, 2022 USD ($) Pre-fundedWarrant $ / shares shares	Sep. 30, 2018	Jun. 30, 2022 USD ($) $ / shares shares	Mar. 31, 2022 shares	Jun. 30, 2022 USD ($) $ / shares shares	Dec. 31, 2021 shares
Class Of Stock [Line Items]
Conversion of warrants to purchase shares	6,837,032		6,837,032		6,837,032
Warrants exercised						0
Cashless exercise of pre-funded warrants to purchase common stock			176,554		176,554
2022 Pre-Funded Warrants and Common Warrants
Class Of Stock [Line Items]
Maximum percentage of holders ownership interest in common stock after exercise	19.99%
Number of amended pre-funded warrants | Pre-fundedWarrant	2
Common Stock
Class Of Stock [Line Items]
Issuance of common stock upon cashless exercise of pre-funded warrants			0	170,668	170,668
Common Stock | Equity Plan Activity
Class Of Stock [Line Items]
Shares issued upon exercise of outstanding stock options			0		0	3,727
Shares issued in connection with employee stock purchase plan			23,461		23,461	36,687
Common Stock | Equity Plan Activity | Restricted Stock Units
Class Of Stock [Line Items]
Shares withheld on vesting date to settle employees minimum statutory tax obligations						0
Shares issued upon vesting of restricted stock units			0		0	0
Common Stock | Direct Offerings
Class Of Stock [Line Items]
Net proceeds received from issuance direct offering | $	$ 3,900,000
Common Stock | Capital on Demand Sales Agreement | Jones Trading Institutional Services LLC
Class Of Stock [Line Items]
Maximum aggregate value of stock to be sold | $	50,000,000		$ 50,000,000		$ 50,000,000
Remaining amount available under the Sales Agreement | $	$ 48,000,000		$ 48,000,000		$ 48,000,000
Percentage of gross proceeds, required to pay for common stock sold through sales agreement		2.50%
Common Stock | 2022 Pre-Funded Warrants | Direct Offerings
Class Of Stock [Line Items]
Exercise price (per share) | $ / shares	$ 0.01		$ 0.01		$ 0.01
Common Stock | Purchase Price of $1.32 Per Share | Direct Offerings
Class Of Stock [Line Items]
Common stock issued and sold	841,989
Common stock purchase price per share | $ / shares	$ 1.32		1.32		1.32
Common Stock | Purchase Price of $1.31 Per Share | 2022 Pre-Funded Warrants | Direct Offerings
Class Of Stock [Line Items]
Common stock purchase price per share | $ / shares	$ 1.31		$ 1.31		$ 1.31
Conversion of warrants to purchase shares	2,205,018		2,205,018		2,205,018

Stockholders' Equity - Schedule

Stockholders' Equity - Schedule of Outstanding Warrants for Purchase of Common Stock Issued (Details)	Jun. 30, 2022 $ / shares shares
Class Of Stock [Line Items]
Warrants issued	6,837,032
January 25, 2024
Class Of Stock [Line Items]
Warrants issued	4,669
Exercise price (per share) | $ / shares	$ 51.40
November 14, 2023 Through June 4, 2024
Class Of Stock [Line Items]
Warrants issued	3,874
Exercise price (per share) | $ / shares	$ 77.40
March 27, 2024
Class Of Stock [Line Items]
Warrants issued	1,369,602
Exercise price (per share) | $ / shares	$ 27
May 3, 2025
Class Of Stock [Line Items]
Warrants issued	5,363
Exercise price (per share) | $ / shares	$ 26.10
August 27, 2030
Class Of Stock [Line Items]
Warrants issued	1,889,513
Exercise price (per share) | $ / shares	$ 0.01
August 31, 2030
Class Of Stock [Line Items]
Warrants issued	1,358,993
Exercise price (per share) | $ / shares	$ 0.01
June 21, 2032
Class Of Stock [Line Items]
Warrants issued	2,205,018
Exercise price (per share) | $ / shares	$ 0.01

Stockholders' Equity - Summary

Stockholders' Equity - Summary of Weighted-Average Assumptions Fair Value of the Employee Stock Option Grants (Details) - Stock Option	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Class Of Stock [Line Items]
Risk-free interest rate	3.60%	1%	1.90%	0.80%
Expected volatility	93%	90%	90%	90%
Expected term (in years)	5 years 6 months	6 years	6 years 2 months 12 days	6 years 2 months 12 days

Stockholders' Equity - Summar_2

Stockholders' Equity - Summary of Allocation of Stock-Based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Class Of Stock [Line Items]
Stock based compensation expense	$ 535	$ 417	$ 1,083	$ 760
Research and development
Class Of Stock [Line Items]
Stock based compensation expense	209	145	409	271
General and administrative
Class Of Stock [Line Items]
Stock based compensation expense	$ 326	$ 272	$ 674	$ 489