Cassava Sciences (SAVA) 10-Q 1 May 23 2023 Q1 Quarterly report Financial data

Document And Entity Information

Document And Entity Information - shares	3 Months Ended
	Mar. 31, 2023	Apr. 27, 2023
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Quarterly Report	true
Document Fiscal Period Focus	Q1
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2023
Document Period End Date	Mar. 31, 2023
Document Transition Report	false
Entity File Number	000-29959
Entity Registrant Name	Cassava Sciences, Inc.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	91-1911336
Entity Address, Address Line One	6801 N. Capital of Texas Highway
Entity Address, Address Line Two	Building 1; Suite 300
Entity Address, City or Town	Austin
Entity Address, State or Province	TX
Entity Address, Postal Zip Code	78731
City Area Code	512
Local Phone Number	501-2444
Title of 12(b) Security	Common Stock, $0.001 par value
Trading Symbol	SAVA
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		41,749,435
Entity Central Index Key	0001069530

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Current assets:
Cash and cash equivalents	$ 187,467	$ 201,015
Prepaid expenses and other current assets	7,532	10,211
Total current assets	194,999	211,226
Operating lease right-of-use assets		122
Property and equipment, net	22,609	22,864
Intangible assets, net	503	622
Total assets	218,111	234,834
Current liabilities:
Accounts payable and accrued expenses	8,242	4,017
Accrued development expense	5,276	2,280
Accrued compensation and benefits	212	170
Operating lease liabilities, current		104
Other current liabilities	179	492
Total current liabilities	13,909	7,063
Operating lease liabilities, non-current		35
Other non-current liabilities	197	197
Total liabilities	14,106	7,295
Commitments and contingencies (Notes 10, 11 and 12)
Stockholders' equity:
Preferred stock, $0.001 par value; 10,000,000 shares authorized, none issued and outstanding
Common stock, $0.001 par value; 120,000,000 shares authorized; 41,749,435 and 41,735,557 shares issued and outstanding at March 31, 2023 and December 31, 2022, respectively	42	42
Additional paid-in capital	511,786	511,049
Accumulated deficit	(307,823)	(283,552)
Total stockholders' equity	204,005	227,539
Total liabilities and stockholders' equity	$ 218,111	$ 234,834

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Mar. 31, 2023	Dec. 31, 2022
Condensed Consolidated Balance Sheets [Abstract]
Preferred stock, par value	$ 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	$ 0.001	$ 0.001
Common stock, shares authorized	120,000,000	120,000,000
Common stock, shares issued	41,749,435	41,735,557
Common stock, shares outstanding	41,749,435	41,735,557

Condensed Consolidated Statemen

Condensed Consolidated Statements Of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Operating expenses:
Research and development, net of grant reimbursement	$ 22,120	$ 14,906
General and administrative	4,392	2,915
Total operating expenses	26,512	17,821
Operating loss	(26,512)	(17,821)
Interest income	2,051	31
Other income, net	190	263
Net loss	$ (24,271)	$ (17,527)
Net income (loss) per share
Net loss per share, Diluted	$ (0.58)	$ (0.44)
Weighted-average shares used in computing net income (loss) per share
Shares used in computing net loss per share, diluted	41,739	39,962

Condensed Consolidated Statem_2

Condensed Consolidated Statements Of Stockholders' Equity - USD ($)	Common Stock [Member]	Additional Paid-In Capital [Member]	Accumulated Deficit [Member]	Total
Balance at Dec. 31, 2021	$ 40,000	$ 461,181,000	$ (207,306,000)	$ 253,915,000
Balance, Shares at Dec. 31, 2021	40,016,792
Stock options for employees		471,000		471,000
Stock options for non-employees		24,000		24,000
Issuance of common stock pursuant to exercise of stock options		211,000		211,000
Issuance of common stock pursuant to exercise of stock options, shares	14,488
Net loss			(17,527,000)	(17,527,000)
Balance at Mar. 31, 2022	$ 40,000	461,887,000	(224,833,000)	237,094,000
Balance, Shares at Mar. 31, 2022	40,031,280
Balance at Dec. 31, 2022	$ 42,000	511,049,000	(283,552,000)	227,539,000
Balance, Shares at Dec. 31, 2022	41,735,557
Stock options for employees		650,000		650,000
Stock options for non-employees		23,000		23,000
Issuance of common stock pursuant to exercise of stock options	$ 13,878	64,000		64,000
Net loss			(24,271,000)	(24,271,000)
Balance at Mar. 31, 2023	$ 42,000	$ 511,786,000	$ (307,823,000)	$ 204,005,000
Balance, Shares at Mar. 31, 2023	41,749,435

Condensed Consolidated Statem_3

Condensed Consolidated Statements Of Cash Flows - USD ($)	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Cash flows from operating activities:
Net loss	$ (24,271,000)	$ (17,527,000)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation	673,000	495,000
Depreciation	272,000	178,000
Amortization of intangible assets	119,000	135,000
Changes in operating assets and liabilities:
Prepaid and other current assets	2,679,000	(1,063,000)
Operating lease right-of-use assets and liabilities	(17,000)	(1,000)
Accounts payable and accrued expenses	4,565,000	(3,794,000)
Accrued development expense	2,996,000	122,000
Accrued compensation and benefits	42,000	(1,705,000)
Other liabilities	(313,000)	(370,000)
Net cash used in operating activities	(13,255,000)	(23,530,000)
Cash flows from investing activities:
Purchases of property and equipment	(357,000)	(425,000)
Net cash used in investing activities	(357,000)	(425,000)
Cash flows from financing activities:
Proceeds from issuance of common stock upon exercise of stock options	64,000	211,000
Net cash provided by financing activities	64,000	211,000
Net decrease in cash and cash equivalents	(13,548,000)	(23,744,000)
Cash and cash equivalents at beginning of period	201,015,000	233,437,000
Cash and cash equivalents at end of period	$ 187,467,000	$ 209,693,000

General And Liquidity

General And Liquidity	3 Months Ended
	Mar. 31, 2023
General And Liquidity [Abstract]
General And Liquidity	Note 1. General and Liquidity Cassava Sciences, Inc. and its wholly-owned subsidiary (collectively referred to as the “Company”) discover and develop proprietary pharmaceutical product candidates that may offer significant improvements to patients and healthcare professionals. The Company generally focuses its discovery and product development efforts on disorders of the nervous system. The accompanying unaudited condensed consolidated financial statements of the Company have been prepared in accordance with accounting principles generally accepted in the United States (“GAAP”) for interim financial information and pursuant to the instructions to the Quarterly Report on Form 10-Q and Article 10 of Regulation S-X. All intercompany transactions and balances have been eliminated in consolidation. Accordingly, the condensed consolidated financial statements do not include all of the information and footnotes required by GAAP for complete consolidated financial statements. In the opinion of management of the Company, all adjustments, consisting of normal recurring adjustments, considered necessary for a fair presentation have been included. Operating results for the three months ended March 31, 2023 are not necessarily indicative of the results that may be expected for any other interim period or for the year 2023 . For further information, refer to the consolidated financial statements and footnotes thereto included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2022. Liquidity The Company has incurred significant net losses and negative cash flows since inception, and as a result has an accumulated deficit of $ 307.8 million at March 31, 2023. The Company expects its cash requirements to be significant in the future. The amount and timing of the Company’s future cash requirements will depend on regulatory and market acceptance of its product candidates and the resources it devotes to researching and developing, formulating, manufacturing, commercializing and supporting its products. The Company may seek additional funding through public or private financing in the future, if such funding is available and on terms acceptable to the Company. There are no assurances that additional financing will be available on favorable terms, or at all. However, management believes that the current working capital position will be sufficient to meet the Company’s working capital needs for at least the next 12 months.

Significant Accounting Policies

Significant Accounting Policies	3 Months Ended
	Mar. 31, 2023
Significant Accounting Policies [Abstract]
Significant Accounting Policies	Note 2. Significant Accounting Policies Use of Estimates The Company makes estimates and assumptions in preparing its condensed consolidated financial statements in conformity with GAAP. These estimates and assumptions affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the condensed consolidated financial statements and the reported amount of revenue earned and expenses incurred during the reporting period. The Company evaluates its estimates on an ongoing basis, including those estimates related to manufacturing agreements and research collaborations. Actual results could differ from these estimates and assumptions. Cash and Cash Equivalents and Concentration of Credit Risk The Company invests in cash and cash equivalents. The Company considers highly liquid financial instruments with original maturities of three months or less to be cash equivalents. Highly liquid investments that are considered cash equivalents include money market accounts and funds, certificates of deposit, and U.S. Treasury securities. The Company maintains its cash and cash equivalents at one financial institution. Fair Value Measurements The Company recognizes financial instruments in accordance with the authoritative guidance on fair value measurements and disclosures for financial assets and liabilities. This guidance defines fair value, establishes a framework for measuring fair value in accordance with GAAP, and expands disclosures about fair value measurements. The guidance also establishes a three-tier fair value hierarchy, which prioritizes the inputs used in measuring fair value. These tiers include:  Level 1 includes quoted prices in active markets.  Level 2 includes significant observable inputs, such as quoted prices for identical or similar securities, or other inputs that are observable and can be corroborated by observable market data for similar securities. The Company uses market pricing and other observable market inputs obtained from third-party providers. It uses the bid price to establish fair value where a bid price is available. The Company does not have any financial instruments where the fair value is based on Level 2 inputs.  Level 3 includes unobservable inputs that are supported by little or no market activity. The Company does not have any financial instruments where the fair value is based on Level 3 inputs. If a financial instrument uses inputs that fall in different levels of the hierarchy, the instrument will be categorized based upon the lowest level of input that is significant to the fair value calculation. The fair value of cash and cash equivalents was based on Level 1 inputs at March 31, 2023 and December 31, 2022.  Business Segments The Company reports segment information based on how it internally evaluates the operating performance of its business units, or segments. The Company’s operations are confined to one business segment: the development of novel drugs and diagnostics. Proceeds from Grants  During the three months ended March 31, 2023, there were no reimbursements received pursuant to National Institutes of Health (“NIH”) research grants. During the three months ended March 31, 2022 , the Company received reimbursements totaling $ 0.1 million pursuant to NIH research grants. The Company records the proceeds from these grants as reductions to its research and development expenses. Stock-based Compensation  The Company recognizes non-cash expense for the fair value of all stock options and other share-based awards. The Company uses the Black-Scholes option valuation model (“Black-Scholes”) to calculate the fair value of stock options, using the single-option award approach and straight-line attribution method. This model requires the input of subjective assumptions including expected stock price volatility, expected life and estimated forfeitures of each award. These assumptions consist of estimates of future market conditions, which are inherently uncertain, and therefore, are subject to management's judgment. For all options granted, it recognizes the resulting fair value as expense on a straight-line basis over the vesting period of each respective stock option, generally four years .  The Company has granted share-based awards that vest upon achievement of certain performance criteria (“Performance Awards”). The Company multiplies the number of Performance Awards by the fair value of its common stock on the date of grant to calculate the fair value of each award. It estimates an implicit service period for achieving performance criteria for each award. The Company recognizes the resulting fair value as expense over the implicit service period when it concludes that achieving the performance criteria is probable. It periodically reviews and updates as appropriate its estimates of implicit service periods and conclusions on achieving the performance criteria. Performance Awards vest and common stock is issued upon achievement of the performance criteria.  Net Loss per Share  The Company computes basic net loss per share on the basis of the weighted-average number of common shares outstanding for the reporting period. Diluted net loss per share is computed on the basis of the weighted-average number of common shares outstanding plus potential dilutive common shares outstanding using the treasury-stock method. Potential dilutive common shares consist of outstanding common stock options. There is no difference between the Company’s net loss and comprehensive loss. The numerators and denominators in the calculation of basic and diluted net loss per share were as follows (in thousands, except net loss per share data): Three months ended March 31, 2023 2022 Numerator: Net loss $ ( 24,271 ) $ ( 17,527 ) Denominator: Shares used in computing net loss per share, basic and diluted 41,739 39,962 Net loss per share, basic and diluted $ ( 0.58 ) $ ( 0.44 ) Dilutive common stock options excluded from net loss per share, diluted 2,034 2,086 The Company excluded common stock options outstanding from the calculation of net loss per share, diluted, because the effect of including outstanding options would have been anti - dilutive. The Company also excluded 57,143 restricted stock awards from the calculation of net loss per share, diluted, until their expiration in June 2022 because the effect of including restricted stock awards would have been anti - dilutive. Fair Value of Financial Instruments Financial instruments include accounts payable and accrued liabilities. The estimated fair value of certain financial instruments may be determined using available market information or other appropriate valuation methodologies. However, considerable judgment is required in interpreting market data to develop estimates of fair value; therefore, the estimates are not necessarily indicative of the amounts that could be realized or would be paid in a current market exchange. The effect of using different market assumptions and/or estimation methodologies may be material to the estimated fair value amounts. The carrying amounts of accounts payable and accrued liabilities are at cost, which approximates fair value due to the short maturity of those instruments. Research Contract Costs and Accruals The Company has entered into various research and development contracts with research institutions and other third-party vendors. These agreements are generally cancelable. Related payments are recorded as research and development expenses as incurred. The Company records prepaids and accruals for estimated ongoing research costs. When evaluating the adequacy of prepaid expenses and accrued liabilities, the Company analyzes progress of the studies including the phase or completion of events, invoices received and contracted costs. Significant judgments and estimates are made in determining the prepaid and accrued balances at the end of any reporting period. Actual results could differ from the Company’s estimates. The Company’s historical prepaid and accrual estimates have not been materially different from actual costs. Incentive Bonus Plan In 2020, the Company established the 2020 Cash Incentive Bonus Plan (the “Plan”) to incentivize Plan participants. Awards under the Plan are accounted for as liability awards under Accounting Standards Codification (ASC) 718 “ Stock-based Compensation ”. The fair value of each potential Plan award will be determined once a grant date occurs and will be remeasured each reporting period. Compensation expense associated with the Plan will be recognized over the expected achievement period for each Plan award, when a Performance Condition (as defined below) is considered probable of being met. See Note 10 for further discussion of the Plan. Leases The Company recognizes assets and liabilities that arise from leases. For operating leases, the Company is required to recognize a right-of-use asset and a lease liability, initially measured at the present value of the lease payments during the lease term, in the condensed consolidated balance sheets. The Company elected the short-term lease recognition exemption for all leases that qualify. This means, for those leases that qualify, the Company does not recognize right-of-use assets or lease liabilities. As the Company`s leases do not provide an implicit rate, it uses its incremental borrowing rate based on the information available at the commencement date in determining the present value of lease payments. Lease expense for lease payments is recognized on a straight-line basis over the lease term. Property and equipment Property and equipment is recorded at cost, net of accumulated depreciation. Depreciation is recorded using the straight-line method over the estimated useful lives of the assets. Owned buildings and related improvements have estimated useful lives of 39 years and approximately 10 years, respectively. Tenant improvements related to leased space are amortized using the straight-line method over the useful lives of the improvements or the remaining term of the corresponding leases, whichever is shorter. The remaining term of the corresponding leases is approximately 1.1 years. Property and equipment are reviewed for impairment when events or changes in circumstances indicate the carrying amount of an asset may not be recoverable. If property and equipment are considered to be impaired, an impairment loss is recognized. Intangible assets Acquired intangible assets are recorded at fair value at the date of acquisition and primarily consist of lease-in-place agreements and leasing commissions. Intangible assets are amortized over the estimated life of the lease-in-place agreements, which is approximately 1.0 years at March 31, 2023. Intangible assets are reviewed for impairment on an annual basis, and when there is reason to believe that their values have been diminished or impaired. If intangible assets are considered to be impaired, an impairment loss is recognized. Income Taxes The Company accounts for income taxes under the asset and liability method. Deferred tax assets and liabilities are recognized for the estimated future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases. Deferred tax balances are adjusted to reflect tax rates based on currently enacted tax laws, which will be in effect in the years in which the temporary differences are expected to reverse. The Company has accumulated significant deferred tax assets that reflect the tax effects of net operating loss and tax credit carryovers and temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes. Realization of certain deferred tax assets is dependent upon future earnings. The Company is uncertain about the timing and amount of any future earnings. Accordingly, the Company offsets these deferred tax assets with a valuation allowance. The Company accounts for uncertain tax positions in accordance with ASC 740, “Income Taxes”, which clarifies the accounting for uncertainty in tax positions. These provisions require recognition of the impact of a tax position in the Company’s condensed consolidated financial statements only if that position is more likely than not of being sustained upon examination by taxing authorities, based on the technical merits of the position. Any interest and penalties related to uncertain tax positions will be reflected as a component of income tax expense.

Prepaid Expenses And Other Curr

Prepaid Expenses And Other Current Assets	3 Months Ended
	Mar. 31, 2023
Prepaid Expenses And Other Current Assets [Abstract]
Prepaid Expenses and Other Current Assets	Note 3. Prepaid Expenses and Other Current Assets Prepaid expenses and other current assets at March 31, 2023 and December 31, 2022 consisted of the following (in thousands): March 31, 2023 December 31, 2022 Prepaid insurance $ 439 $ 874 Contract research organization and other deposits 6,816 9,177 Other 277 160 Total prepaid expenses and other current assets $ 7,532 $ 10,211 Contract research organization and other deposits represent cash payments made to vendors in excess of expenses incurred.

Real Property

Real Property	3 Months Ended
	Mar. 31, 2023
Real Property [Abstract]
Real Property	Note 4. Real Property The Company owns a two-building office complex in Austin, Texas, a portion of which serves as its corporate headquarters. This property is intended to accommodate the Company’s anticipated growth and expansion of its operations in the coming years. Maintenance, physical facilities, leasing, property management and other key responsibilities related to property ownership are being outsourced to professional real-estate managers. The office complex measures approximately 90,000 rentable square feet. At March 31, 2023, the property was over 60 % leased. The Company also occupies approximately 25 % of the property. The Company records the net income from building operations and leases as other income, net, as leasing is not core to the Company’s operations. Building depreciation and amortization for space not occupied by the Company is included in general and administrative expense. Building depreciation and amortization for space occupied by the Company is allocated between general and administrative expense and research and development expense. Components of other income, net, for the periods presented were as follows (in thousands): Three months ended March 31, 2023 2022 Lease revenue $ 557 $ 573 Property operating expenses ( 367 ) ( 310 ) Other income, net $ 190 $ 263

Property And Equipment

Property And Equipment	3 Months Ended
	Mar. 31, 2023
Property And Equipment [Abstract]
Property And Equipment	Note 5. Property and equipment The components of property and equipment, net, as of March 31, 2023 and December 31, 2022 were as follows (in thousands): March 31, 2023 December 31, 2022 Land $ 3,734 $ 3,734 Buildings 15,980 15,980 Site improvements 470 470 Tenant improvements 3,016 3,016 Furniture and equipment 868 851 Construction in progress 13 13 Gross property and equipment $ 24,081 $ 24,064 Accumulated depreciation ( 1,472 ) ( 1,200 ) Property and equipment, net $ 22,609 $ 22,864 Depreciation expense for property and equipment was $ 272,000 and $ 178,000 for the three months ended March 31, 2023 and 2022, respectively.

Intangible Assets

Intangible Assets	3 Months Ended
	Mar. 31, 2023
Intangible Assets [Abstract]
Intangible Assets	Note 6. Intangible assets The components of intangible assets, net, as of March 31, 2023 and December 31, 2022 were as follows (in thousands): March 31, 2023 December 31, 2022 Lease-in-place agreements $ 1,053 $ 1,053 Leasing commissions and other 290 290 Gross intangible assets $ 1,343 $ 1,343 Accumulated amortization ( 840 ) ( 721 ) Intangible assets, net $ 503 $ 622 Amortization expense for intangible assets was $ 119,000 and $ 135,000 for the three months ended March 31, 2023 and 2022, respectively. Amortization expense for finite-lived intangible assets as of March 31, 2023 is expected to be as follows (in thousands): For the year ending December 31, 2023 $ 332 2024 167 2025 4 Total amortization $ 503

Stockholders' Equity And Stock-

Stockholders' Equity And Stock-Based Compensation Expense	3 Months Ended
	Mar. 31, 2023
Stockholders’ Equity And Stock-Based Compensation Expense [Abstract]
Stockholders' Equity And Stock-Based Compensation Expense	Note 7. Stockholders’ Equity and Stock-Based Compensation Expense 2022 Registered Direct Offering On November 22, 2022, the Company completed a common stock offering pursuant to which certain investors purchased 1,666,667 shares of common stock at a price of $ 30.00 per share. Net proceeds of the offering were approximately $ 47.3 million after deducting offering expenses. At-the-Market Common Stock Offering In March 2020, the Company established an at-the-market offering program (“2020 Program”) to sell, from time to time, shares of Company common stock having an aggregate offering price of up to $ 100 million in transactions pursuant to a shelf registration statement that was declared effective by the U.S. Securities and Exchange Commission (the “SEC”) on May 5, 2020 . The Company gave notice of termination for the 2020 Program on April 26, 2023, which is effective May 1, 2023. There were no common stock sales under the 2020 Program through its termination. Stock Option and Performance Award Activity in 2023 During the three months ended March 31 , 2023, stock options and unvested Performance Awards outstanding under the Company’s stock option plans changed as follows: Stock Options Performance Awards Outstanding as of December 31, 2022 2,529,448 7,142 Options granted — — Options exercised ( 19,017 ) — Options forfeited/canceled — — Outstanding as of March 31, 2023 2,510,431 7,142 The weighted average exercise price of options outstanding at March 31 , 2023 was $ 12.15 . As outstanding options vest over the current remaining vesting period of 2.3 years, the Company expects to recognize stock-based compensation expense of $ 7.0 million. If and when outstanding Performance Awards vest, the Company will recognize stock-based compensation expense of $ 0.1 million over the implicit service period. During the three months ended March 31 , 2023, there were 19,017 stock options exercised. Of the stock options exercised, 5,139 stock options were net settled in satisfaction of the exercise price, with no cash proceeds received. Cash proceeds to the Company for options not net settled totaled $ 64,000 during the three months ended March 31 , 2023. During the three months ended March 31, 2022, there were 19,609 stock options exercised. Of the stock options exercised, 5,121 stock options were net settled in satisfaction of the exercise price, with no cash proceeds received. Cash proceeds to the Company for options not net settled totaled $ 211,000 during the three months ended March 31, 2022. Stock-based Compensation Expense in 2023 During the three and nine months ended March 31 , 2023 and 2022, the Company’s stock-based compensation expense was as follows (in thousands): Three months ended March 31, 2023 2022 Research and development $ 389 $ 422 General and administrative 284 73 Total stock-based compensation expense $ 673 $ 495 2018 Equity Incentive Plan The Company’s Board of Directors (the “Board”) or a designated committee of the Board is responsible for administration of the Company’s 2018 Omnibus Incentive Plan, as amended (the “2018 Plan”) and determines the terms and conditions of each option granted, consistent with the terms of the 2018 Plan. The Company’s employees, directors, and consultants are eligible to receive awards under the 2018 Plan, including grants of stock options and Performance Awards. Share-based awards generally expire 10 years from the date of grant. The 2018 Plan, as amended on May 5, 2022, provides for issuance of up to 5,000,000 shares of common stock, par value $ 0.001 per share, subject to adjustment as provided in the 2018 Plan.  When stock options or Performance Awards are exercised net of the exercise price and taxes, the number of shares of stock issued is reduced by the number of shares equal to the amount of taxes owed by the award recipient and that number of shares are cancelled. The Company then uses its cash to pay tax authorities the amount of statutory taxes owed by and on behalf of the award recipient.

Income Taxes

Income Taxes	3 Months Ended
	Mar. 31, 2023
Income Taxes [Abstract]
Income Taxes	Note 8. Income Taxes The Company did no t provide for income taxes during the three months ended March 31 , 2023 , because it has projected a net loss for the full year 2023 for which any benefit will be offset by an increase in the valuation allowance . There was also no provision for income taxes for the three months ended March 31 , 2022.

Commitments

Commitments	3 Months Ended
	Mar. 31, 2023
Commitments [Abstract]
Commitments	Note 9. Commitments Right-of-use Asset and Liability The Company had an operating lease for approximately 6,000 square feet of office space in Austin, Texas with an expiration of April 30, 2024 . The Company and the landlord consented to early terminate this lease on February 22, 2023 with no continuing obligations. Rent expense for the three months ended March 31 , 2023 and 2022 totaled $ 24,000 and $ 41,000 , respectively. Cash paid for operating lease liabilities during the three months ended March 31 , 2023 and 2022 totaled $ 24,000 and $ 41,000 , respectively. Other Commitments The Company conducts its product research and development programs through a combination of internal and collaborative programs that include, among others, arrangements with universities, contract research organizations and clinical research sites. The Company has contractual arrangements with these organizations that are cancelable. The Company’s obligations under these contracts are largely based on services performed.

2020 Cash Incentive Bonus Plan

2020 Cash Incentive Bonus Plan	3 Months Ended
	Mar. 31, 2023
2020 Cash Incentive Bonus Plan [Abstract]
2020 Cash Incentive Bonus Plan	Note 10. 2020 Cash Incentive Bonus Plan In August 2020, the Board approved the Plan. The Plan was established to promote the long-term success of the Company by creating an “at-risk” cash bonus program that rewards Plan participants with additional cash compensation in lockstep with significant increases in the Company’s market capitalization. The Plan is considered “at-risk” because Plan participants will not receive a cash bonus unless the Company’s market capitalization increases significantly and certain other conditions specified in the Plan are met. Specifically, Plan participants will not be paid any cash bonuses unless (1) the Company completes a merger or acquisition transaction that constitutes a sale of ownership of the Company or its assets (a Merger Transaction) or (2) the Compensation Committee of the Board (the Compensation Committee) determines the Company has sufficient cash on hand, as defined in the Plan. Because of the inherent discretion and uncertainty regarding these requirements, the Company has concluded that a Plan grant date has not occurred as of March 31 , 2023. Plan participants will be paid all earned cash bonuses in the event of a Merger Transaction. As of December 31, 2022, the Company’s independent directors were participants in the Plan. However, effective March 16, 2023, the Board of Directors amended the Plan to remove all independent directors as participants in the Plan and the independent directors consented to such removal. The independent directors’ share of potential benefits under the Plan were completely forfeited to the Company and will not be allocated to any other participant under the Plan. The Company’s independent directors have no t received, and as a result of such amendment will never receive, any payments under the Plan. The Company’s market capitalization for purposes of the Plan is determined based on either (1) the closing price of one share of the Company’s common stock on the Nasdaq Capital Market multiplied by the total issued and outstanding shares and options to purchase shares of the Company, or (2) the aggregate consideration payable to security holders of the Company in a Merger Transaction. This constitutes a market condition under applicable accounting guidance. The Plan triggers a potential cash bonus each time the Company’s market capitalization increases significantly, up to a maximum $ 5 billion in market capitalization. The Plan specifies 14 incremental amounts between $ 200 million and $ 5 billion (each increment, a “Valuation Milestone”). Each Valuation Milestone triggers a potential cash bonus award in a pre-set amount defined in the Plan. Each Valuation Milestone must be achieved and maintained for no less than 20 consecutive trading days for Plan participants to be eligible for a potential cash bonus award. Approximately 67 % of each cash bonus award associated with a Valuation Milestone is subject to adjustment and approval by the Compensation Committee. Any amounts not awarded by the Compensation Committee are no longer available for distribution. If the Company were to exceed a $ 5 billion market capitalization for no less than 20 consecutive trading days, all Valuation Milestones would be deemed achieved, in which case cash bonus awards would range from a minimum of $ 111.4 million up to a hypothetical maximum of $ 289.7 million. Payment of cash bonuses is deferred until such time as (1) the Company completes a Merger Transaction, or (2) the Compensation Committee determines the Company has sufficient cash on hand to render payment (each, a “Performance Condition”), neither of which may ever occur. Accordingly, there can be no assurance that Plan participants will ever be paid a cash bonus that is awarded under the Plan, even if the Company’s market capitalization increases significantly. The Plan is accounted for as a liability award. The fair value of each Valuation Milestone award will be determined once a grant date occurs and will be remeasured each reporting period. Compensation expense associated with the Plan will be recognized over the expected achievement period for each of the 14 Valuation Milestones, when a Performance Condition is considered probable of being met. In October 2020, the Company achieved the first Valuation Milestone. Subsequently, the Compensation Committee approved a potential cash bonus award of $ 6.5 million in total for all Plan participants (after the March 2023 Plan amendment), subject to future satisfaction of a Performance Condition. During the year ended December 31, 2021, the Company achieved 11 additional Valuation Milestones triggering potential Company obligations to all Plan participants from a minimum of $ 74.9 million up to a hypothetical maximum of $ 202.3 million (after the March 2023 Plan amendment), to be determined by the Compensation Committee and contingent upon future satisfaction of a Performance Condition. However, no compensation expense was recorded since no grant date has occurred and no Performance Conditions are considered probable of being met. There is no continuing service requirement for Plan participants once the Compensation Committee approves a cash bonus award. No Valuation Milestones were achieved during 2022 or the three months ended March 31, 2023. No actual cash payments were authorized or made to participants under the Plan through May 1, 2023.

Contingencies

Contingencies	3 Months Ended
	Mar. 31, 2023
Contingencies [Abstract]
Contingencies	Note 11. Contingencies From time to time, the Company may become involved in litigation or other legal proceedings and claims, including U.S. government inquiries, investigations and Citizen Petitions submitted to FDA, and may receive inquiries from government authorities relating to matters arising from the ordinary course of business . The outcome of these proceedings is inherently uncertain. Regardless of outcome, legal proceedings can have an adverse impact on the Company because of defense and settlement costs, diversion of management resources, and other factors. At this time, no assessment can be made as to their likely outcome or whether the outcome will be material to the Company. No information is available to indicate that it is probable that a loss has been incurred or can be reasonably estimated as of the date of the condensed consolidated financial statements and, as such, no accrual for these matters has been recorded within the condensed consolidated financial statements. Government Investigations On November 15, 2021, the Company disclosed that certain government agencies had asked it to provide them with corporate information and documents. These were confidential requests. The Company has been voluntarily cooperating and will continue to cooperate with government authorities. No government agency has informed the Company that it has found evidence of research misconduct. No government agency has informed the Company that any wrongdoing has occurred by any party. No government agency has filed any charges against the Company, or anyone associated with it. We cannot predict the outcome or impact of these ongoing matters, including whether a government agency may pursue an enforcement action against the Company or others. Securities Class Actions and Shareholder Derivative Actions Between August 27, 2021 and October 26, 2021, four putative class action lawsuits were filed alleging violations of the federal securities laws by the Company and certain named officers. The complaints rely on allegations contained in Citizen Petitions submitted to FDA and allege that various statements made by the defendants regarding simufilam were rendered materially false and misleading. The Citizen Petitions were all subsequently denied by FDA. These actions were filed in the U.S. District Court for the Western District of Texas. The complaints seek unspecified compensatory damages and other relief on behalf of a purported class of purchasers. On June 30, 2022, a federal judge consolidated the four class action lawsuits into one case and appointed a lead plaintiff and a lead counsel. Lead plaintiff filed a consolidated amended complaint on August 18, 2022 on behalf of a putative class of purchasers of the Company’s securities between September 14, 2020 and July 26, 2022. Briefing on defendants’ motion to dismiss was completed on January 23, 2023 and an argument on defendants’ motion was held on April 26, 2023 . The Company believes the claims are without merit and intends to defend against these lawsuits vigorously. The Company is unable to estimate the possible loss or range of loss, if any, associated with these lawsuits. On November 4, 2021, a related shareholder derivative action was filed, purportedly on behalf of the Company, in the U.S. District Court for the Western District of Texas, asserting claims under the U.S. securities laws and state fiduciary duty laws against certain named officers and the members of the Company’s board of directors. This complaint relies on the allegations made in Citizen Petitions that were submitted to (and subsequently denied by) FDA. The complaint alleges, among other things, that the individual defendants exposed the Company to unspecified damages and securities law liability by causing it to make materially false and misleading statements, in violation of the U.S. securities laws and in breach of their fiduciary duties to the Company. The derivative case seeks, among other things, to recover unspecified compensatory damages on behalf of the Company arising out of the individual defendant’s alleged wrongful conduct. Although the plaintiff in this derivative case does not seek relief against the Company, the Company has certain indemnification obligations to the individual defendants. Since November 4, 2021, three additional shareholder derivative actions were filed alleging substantially similar claims, two in the U.S. District Court for the Western District of Texas, and one in Texas state court (Travis County District Court). All four actions have been stayed pending the resolution of the motions to dismiss in the securities class actions. On July 5, 2022, the three federal court actions were consolidated into a single action. On August 19, 2022, a shareholder derivative action was filed, purportedly on behalf of the Company, in the Delaware Court of Chancery, asserting claims under state fiduciary duty laws against certain named officers and members of the Company’s board of directors. The complaint alleges, among other things, that the individual defendants breached their fiduciary duties by approving the 2020 Cash Incentive Bonus Plan in August 2020. The complaints seek unspecified compensatory damages and other relief. On January 6, 2023, the plaintiffs filed an amended complaint. Defendants filed a partial answer to the amended complaint on March 10, 2023, and moved to partially dismiss the amended complaint on March 14, 2023. Defendants’ motion to dismiss remains pending. Although the plaintiffs in this derivative case do not seek relief against the Company, the Company has certain indemnification obligations to the individual defendants. The Company is unable to estimate the possible loss or range of loss, if any, associated with these lawsuits.

Significant Accounting Polici_2

Significant Accounting Policies (Policy)	3 Months Ended
	Mar. 31, 2023
Significant Accounting Policies [Abstract]
Use Of Estimates	Use of Estimates The Company makes estimates and assumptions in preparing its condensed consolidated financial statements in conformity with GAAP. These estimates and assumptions affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the condensed consolidated financial statements and the reported amount of revenue earned and expenses incurred during the reporting period. The Company evaluates its estimates on an ongoing basis, including those estimates related to manufacturing agreements and research collaborations. Actual results could differ from these estimates and assumptions.
Cash And Cash Equivalents And Concentration Of Credit Risk	Cash and Cash Equivalents and Concentration of Credit Risk The Company invests in cash and cash equivalents. The Company considers highly liquid financial instruments with original maturities of three months or less to be cash equivalents. Highly liquid investments that are considered cash equivalents include money market accounts and funds, certificates of deposit, and U.S. Treasury securities. The Company maintains its cash and cash equivalents at one financial institution.
Fair Value Measurements	Fair Value Measurements The Company recognizes financial instruments in accordance with the authoritative guidance on fair value measurements and disclosures for financial assets and liabilities. This guidance defines fair value, establishes a framework for measuring fair value in accordance with GAAP, and expands disclosures about fair value measurements. The guidance also establishes a three-tier fair value hierarchy, which prioritizes the inputs used in measuring fair value. These tiers include:  Level 1 includes quoted prices in active markets.  Level 2 includes significant observable inputs, such as quoted prices for identical or similar securities, or other inputs that are observable and can be corroborated by observable market data for similar securities. The Company uses market pricing and other observable market inputs obtained from third-party providers. It uses the bid price to establish fair value where a bid price is available. The Company does not have any financial instruments where the fair value is based on Level 2 inputs.  Level 3 includes unobservable inputs that are supported by little or no market activity. The Company does not have any financial instruments where the fair value is based on Level 3 inputs. If a financial instrument uses inputs that fall in different levels of the hierarchy, the instrument will be categorized based upon the lowest level of input that is significant to the fair value calculation. The fair value of cash and cash equivalents was based on Level 1 inputs at March 31, 2023 and December 31, 2022.
Business Segments	Business Segments The Company reports segment information based on how it internally evaluates the operating performance of its business units, or segments. The Company’s operations are confined to one business segment: the development of novel drugs and diagnostics.
Proceeds From Grants	Proceeds from Grants  During the three months ended March 31, 2023, there were no reimbursements received pursuant to National Institutes of Health (“NIH”) research grants. During the three months ended March 31, 2022 , the Company received reimbursements totaling $ 0.1 million pursuant to NIH research grants. The Company records the proceeds from these grants as reductions to its research and development expenses.
Stock-Based Compensation	Stock-based Compensation  The Company recognizes non-cash expense for the fair value of all stock options and other share-based awards. The Company uses the Black-Scholes option valuation model (“Black-Scholes”) to calculate the fair value of stock options, using the single-option award approach and straight-line attribution method. This model requires the input of subjective assumptions including expected stock price volatility, expected life and estimated forfeitures of each award. These assumptions consist of estimates of future market conditions, which are inherently uncertain, and therefore, are subject to management's judgment. For all options granted, it recognizes the resulting fair value as expense on a straight-line basis over the vesting period of each respective stock option, generally four years .  The Company has granted share-based awards that vest upon achievement of certain performance criteria (“Performance Awards”). The Company multiplies the number of Performance Awards by the fair value of its common stock on the date of grant to calculate the fair value of each award. It estimates an implicit service period for achieving performance criteria for each award. The Company recognizes the resulting fair value as expense over the implicit service period when it concludes that achieving the performance criteria is probable. It periodically reviews and updates as appropriate its estimates of implicit service periods and conclusions on achieving the performance criteria. Performance Awards vest and common stock is issued upon achievement of the performance criteria.
Net Loss Per Share	Net Loss per Share  The Company computes basic net loss per share on the basis of the weighted-average number of common shares outstanding for the reporting period. Diluted net loss per share is computed on the basis of the weighted-average number of common shares outstanding plus potential dilutive common shares outstanding using the treasury-stock method. Potential dilutive common shares consist of outstanding common stock options. There is no difference between the Company’s net loss and comprehensive loss. The numerators and denominators in the calculation of basic and diluted net loss per share were as follows (in thousands, except net loss per share data): Three months ended March 31, 2023 2022 Numerator: Net loss $ ( 24,271 ) $ ( 17,527 ) Denominator: Shares used in computing net loss per share, basic and diluted 41,739 39,962 Net loss per share, basic and diluted $ ( 0.58 ) $ ( 0.44 ) Dilutive common stock options excluded from net loss per share, diluted 2,034 2,086 The Company excluded common stock options outstanding from the calculation of net loss per share, diluted, because the effect of including outstanding options would have been anti - dilutive. The Company also excluded 57,143 restricted stock awards from the calculation of net loss per share, diluted, until their expiration in June 2022 because the effect of including restricted stock awards would have been anti - dilutive.
Fair Value Of Financial Instruments	Fair Value of Financial Instruments Financial instruments include accounts payable and accrued liabilities. The estimated fair value of certain financial instruments may be determined using available market information or other appropriate valuation methodologies. However, considerable judgment is required in interpreting market data to develop estimates of fair value; therefore, the estimates are not necessarily indicative of the amounts that could be realized or would be paid in a current market exchange. The effect of using different market assumptions and/or estimation methodologies may be material to the estimated fair value amounts. The carrying amounts of accounts payable and accrued liabilities are at cost, which approximates fair value due to the short maturity of those instruments.
Research Contract Costs And Accruals	Research Contract Costs and Accruals The Company has entered into various research and development contracts with research institutions and other third-party vendors. These agreements are generally cancelable. Related payments are recorded as research and development expenses as incurred. The Company records prepaids and accruals for estimated ongoing research costs. When evaluating the adequacy of prepaid expenses and accrued liabilities, the Company analyzes progress of the studies including the phase or completion of events, invoices received and contracted costs. Significant judgments and estimates are made in determining the prepaid and accrued balances at the end of any reporting period. Actual results could differ from the Company’s estimates. The Company’s historical prepaid and accrual estimates have not been materially different from actual costs.
Incentive Bonus Plan	Incentive Bonus Plan In 2020, the Company established the 2020 Cash Incentive Bonus Plan (the “Plan”) to incentivize Plan participants. Awards under the Plan are accounted for as liability awards under Accounting Standards Codification (ASC) 718 “ Stock-based Compensation ”. The fair value of each potential Plan award will be determined once a grant date occurs and will be remeasured each reporting period. Compensation expense associated with the Plan will be recognized over the expected achievement period for each Plan award, when a Performance Condition (as defined below) is considered probable of being met. See Note 10 for further discussion of the Plan.
Leases	Leases The Company recognizes assets and liabilities that arise from leases. For operating leases, the Company is required to recognize a right-of-use asset and a lease liability, initially measured at the present value of the lease payments during the lease term, in the condensed consolidated balance sheets. The Company elected the short-term lease recognition exemption for all leases that qualify. This means, for those leases that qualify, the Company does not recognize right-of-use assets or lease liabilities. As the Company`s leases do not provide an implicit rate, it uses its incremental borrowing rate based on the information available at the commencement date in determining the present value of lease payments. Lease expense for lease payments is recognized on a straight-line basis over the lease term.
Property And Equipment	Property and equipment Property and equipment is recorded at cost, net of accumulated depreciation. Depreciation is recorded using the straight-line method over the estimated useful lives of the assets. Owned buildings and related improvements have estimated useful lives of 39 years and approximately 10 years, respectively. Tenant improvements related to leased space are amortized using the straight-line method over the useful lives of the improvements or the remaining term of the corresponding leases, whichever is shorter. The remaining term of the corresponding leases is approximately 1.1 years. Property and equipment are reviewed for impairment when events or changes in circumstances indicate the carrying amount of an asset may not be recoverable. If property and equipment are considered to be impaired, an impairment loss is recognized.
Intangible Assets	Intangible assets Acquired intangible assets are recorded at fair value at the date of acquisition and primarily consist of lease-in-place agreements and leasing commissions. Intangible assets are amortized over the estimated life of the lease-in-place agreements, which is approximately 1.0 years at March 31, 2023. Intangible assets are reviewed for impairment on an annual basis, and when there is reason to believe that their values have been diminished or impaired. If intangible assets are considered to be impaired, an impairment loss is recognized.
Income Taxes	Income Taxes The Company accounts for income taxes under the asset and liability method. Deferred tax assets and liabilities are recognized for the estimated future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases. Deferred tax balances are adjusted to reflect tax rates based on currently enacted tax laws, which will be in effect in the years in which the temporary differences are expected to reverse. The Company has accumulated significant deferred tax assets that reflect the tax effects of net operating loss and tax credit carryovers and temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes. Realization of certain deferred tax assets is dependent upon future earnings. The Company is uncertain about the timing and amount of any future earnings. Accordingly, the Company offsets these deferred tax assets with a valuation allowance. The Company accounts for uncertain tax positions in accordance with ASC 740, “Income Taxes”, which clarifies the accounting for uncertainty in tax positions. These provisions require recognition of the impact of a tax position in the Company’s condensed consolidated financial statements only if that position is more likely than not of being sustained upon examination by taxing authorities, based on the technical merits of the position. Any interest and penalties related to uncertain tax positions will be reflected as a component of income tax expense.

Significant Accounting Polici_3

Significant Accounting Policies (Tables)	3 Months Ended
	Mar. 31, 2023
Significant Accounting Policies [Abstract]
Numerators And Denominators In The Calculation Of Basic And Diluted Net Loss Per Share	Three months ended March 31, 2023 2022 Numerator: Net loss $ ( 24,271 ) $ ( 17,527 ) Denominator: Shares used in computing net loss per share, basic and diluted 41,739 39,962 Net loss per share, basic and diluted $ ( 0.58 ) $ ( 0.44 ) Dilutive common stock options excluded from net loss per share, diluted 2,034 2,086

Prepaid Expenses And Other Cu_2

Prepaid Expenses And Other Current Assets (Tables)	3 Months Ended
	Mar. 31, 2023
Prepaid Expenses And Other Current Assets [Abstract]
Schedule Of Prepaid Expenses And Other Current Assets	March 31, 2023 December 31, 2022 Prepaid insurance $ 439 $ 874 Contract research organization and other deposits 6,816 9,177 Other 277 160 Total prepaid expenses and other current assets $ 7,532 $ 10,211

Real Property (Tables)

Real Property (Tables)	3 Months Ended
	Mar. 31, 2023
Real Property [Abstract]
Components Of Other Income, Net	Three months ended March 31, 2023 2022 Lease revenue $ 557 $ 573 Property operating expenses ( 367 ) ( 310 ) Other income, net $ 190 $ 263

Property And Equipment (Tables)

Property And Equipment (Tables)	3 Months Ended
	Mar. 31, 2023
Property And Equipment [Abstract]
Components Of Property And Equipment, Net	March 31, 2023 December 31, 2022 Land $ 3,734 $ 3,734 Buildings 15,980 15,980 Site improvements 470 470 Tenant improvements 3,016 3,016 Furniture and equipment 868 851 Construction in progress 13 13 Gross property and equipment $ 24,081 $ 24,064 Accumulated depreciation ( 1,472 ) ( 1,200 ) Property and equipment, net $ 22,609 $ 22,864

Intangible Assets (Tables)

Intangible Assets (Tables)	3 Months Ended
	Mar. 31, 2023
Intangible Assets [Abstract]
Components Of Intangible Assets, Net	March 31, 2023 December 31, 2022 Lease-in-place agreements $ 1,053 $ 1,053 Leasing commissions and other 290 290 Gross intangible assets $ 1,343 $ 1,343 Accumulated amortization ( 840 ) ( 721 ) Intangible assets, net $ 503 $ 622
Amortization Expense For Finite-Lived Intangible Assets	For the year ending December 31, 2023 $ 332 2024 167 2025 4 Total amortization $ 503

Stockholders' Equity And Stoc_2

Stockholders' Equity And Stock-Based Compensation Expense (Tables)	3 Months Ended
	Mar. 31, 2023
Stockholders’ Equity And Stock-Based Compensation Expense [Abstract]
Stock Options And Unvested Performance Award Outstanding Activity	Stock Options Performance Awards Outstanding as of December 31, 2022 2,529,448 7,142 Options granted — — Options exercised ( 19,017 ) — Options forfeited/canceled — — Outstanding as of March 31, 2023 2,510,431 7,142
Stock-Based Compensation Expense	Three months ended March 31, 2023 2022 Research and development $ 389 $ 422 General and administrative 284 73 Total stock-based compensation expense $ 673 $ 495

General And Liquidity (Narrativ

General And Liquidity (Narrative) (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
General And Liquidity [Abstract]
Accumulated deficit	$ 307,823	$ 283,552

Significant Accounting Polici_4

Significant Accounting Policies (Narrative) (Details) $ in Millions	3 Months Ended
	Mar. 31, 2023 USD ($) segment shares	Mar. 31, 2022 USD ($)
Summary Of Significant Accounting Policies [Line Items]
Reimbursement from National Institutes of Health research grants | $	$ 0	$ 0.1
Number of business segments | segment	1
Vesting period of stock options	4 years
Lease-In-Place Agreements [Member]
Summary Of Significant Accounting Policies [Line Items]
Intangible assets, Estimated useful lives	1 year
Buildings [Member]
Summary Of Significant Accounting Policies [Line Items]
Property and equipment, Estimated useful lives	39 years
Site Improvements [Member]
Summary Of Significant Accounting Policies [Line Items]
Property and equipment, Estimated useful lives	10 years
Tenant Improvements [Member]
Summary Of Significant Accounting Policies [Line Items]
Property and equipment, Estimated useful lives	1 year 1 month 6 days
Restricted Stock [Member]
Summary Of Significant Accounting Policies [Line Items]
Dilutive common stock options excluded from net loss per share, diluted | shares	57,143

Significant Accounting Polici_5

Significant Accounting Policies (Numerators And Denominators In The Calculation Of Basic And Diluted Net Loss Per Share) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Numerator:
Net loss	$ (24,271)	$ (17,527)
Denominator:
Shares used in computing net loss per share, diluted	41,739	39,962
Net loss per share, Diluted	$ (0.58)	$ (0.44)
Stock Option [Member]
Denominator:
Dilutive common stock options excluded from net loss per share, diluted	2,034	2,086

Prepaid Expenses And Other Cu_3

Prepaid Expenses And Other Current Assets (Schedule Of Prepaid Expenses And Other Current Assets) (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Prepaid Expenses And Other Current Assets [Abstract]
Prepaid insurance	$ 439	$ 874
Contract research organization and other deposits	6,816	9,177
Other	277	160
Total prepaid expenses and other current assets	$ 7,532	$ 10,211

Real Property (Narrative) (Deta

Real Property (Narrative) (Details) - Austin, Texas [Member] - Two-building office complex [Member] - ft²	3 Months Ended
	Mar. 31, 2023	Aug. 04, 2021
Asset Acquisition [Line Items]
Percentage Of Occupancy	25%
Percentage Of Currently Leased	60%
Net Rentable Area		90,000

Real Property (Components Of Ot

Real Property (Components Of Other Income, Net) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Business Acquisition [Line Items]
Other income, net	$ 190	$ 263
Buildings [Member] | Austin, Texas [Member]
Business Acquisition [Line Items]
Lease revenue	557	573
Property operating expenses	(367)	(310)
Other income, net	$ 190	$ 263

Property And Equipment (Narrati

Property And Equipment (Narrative) (Details) - USD ($)	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Property And Equipment [Abstract]
Depreciation expense	$ 272,000	$ 178,000

Property And Equipment (Compone

Property And Equipment (Components Of Property And Equipment, Net) (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Property, Plant and Equipment [Line Items]
Gross property and equipment	$ 24,081	$ 24,064
Accumulated depreciation	(1,472)	(1,200)
Property and equipment, net	22,609	22,864
Land [Member]
Property, Plant and Equipment [Line Items]
Gross property and equipment	3,734	3,734
Buildings [Member]
Property, Plant and Equipment [Line Items]
Gross property and equipment	15,980	15,980
Site Improvements [Member]
Property, Plant and Equipment [Line Items]
Gross property and equipment	470	470
Tenant Improvements [Member]
Property, Plant and Equipment [Line Items]
Gross property and equipment	3,016	3,016
Furniture And Equipment [Member]
Property, Plant and Equipment [Line Items]
Gross property and equipment	868	851
Construction In Progress [Member]
Property, Plant and Equipment [Line Items]
Gross property and equipment	$ 13	$ 13

Intangible Assets (Narrative) (

Intangible Assets (Narrative) (Details) - USD ($)	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Intangible Assets [Abstract]
Amortization expense for intangible assets	$ 119,000	$ 135,000

Intangible Assets (Components O

Intangible Assets (Components Of Intangible Assets, Net) (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Finite-Lived Intangible Assets [Line Items]
Gross intangible assets	$ 1,343	$ 1,343
Accumulated amortization	(840)	(721)
Intangible assets, net	503	622
Lease-In-Place Agreements [Member]
Finite-Lived Intangible Assets [Line Items]
Gross intangible assets	1,053	1,053
Leasing Commissions And Other [Member]
Finite-Lived Intangible Assets [Line Items]
Gross intangible assets	$ 290	$ 290

Intangible Assets (Amortization

Intangible Assets (Amortization Expense For Finite-Lived Intangible Assets) (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Intangible Assets [Abstract]
2023	$ 332
2024	167
2025	4
Intangible assets, net	$ 503	$ 622

Stockholders' Equity And Stoc_3

Stockholders' Equity And Stock-Based Compensation Expense (Narrative) (Details) - USD ($)				1 Months Ended	3 Months Ended
	Apr. 30, 2023	Nov. 22, 2022	May 05, 2022	Mar. 31, 2020	Mar. 31, 2023	Mar. 31, 2022	Dec. 31, 2022
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Proceeds from issuance of common stock upon exercise of stock options					$ 64,000	$ 211,000
Vesting period of stock options					4 years
Stock-based compensation expense					$ 673,000	$ 495,000
Par value per share					$ 0.001		$ 0.001
ATM [Member]
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Number of shares issued	0
ATM [Member] | Maximum [Member]
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Aggregate offering price				$ 100,000,000
2018 Equity Incentive Plan [Member]
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Expiration period					10 years
Par value per share			$ 0.001
2018 Equity Incentive Plan [Member] | Maximum [Member]
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Shares issued			5,000,000
Stock Option [Member]
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock options exercised					19,017	19,609
Proceeds from issuance of common stock upon exercise of stock options					$ 64,000	$ 211,000
Stock options exercised, net settled in satisfaction of the exercise price					5,139	5,121
Proceeds from stock options exercised net settled in satisfaction of the exercise price					$ 0	$ 0
Stock Option [Member] | Stock Option And Performance Award [Member]
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Weighted average exercise price or options					$ 12.15
Vesting period of stock options					2 years 3 months 18 days
Stock-based compensation expense					$ 7,000,000
Performance Award [Member]
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense					$ 100,000
Common Stock [Member] | Registered Direct Offering 2022 [Member]
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Number of shares issued		1,666,667
Price per share		$ 30
Proceeds from offering		$ 47,300,000

Stockholders' Equity And Stoc_4

Stockholders' Equity And Stock-Based Compensation Expense (Stock Options And Unvested Performance Award Outstanding Activity) (Details) - shares	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Outstanding as of, Beginning	2,529,448
Options granted
Options exercised	(19,017)	(19,609)
Options forfeited/canceled
Outstanding as of, Ending	2,510,431
Performance Award [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Outstanding as of, Beginning	7,142
Options granted
Vested
Options forfeited/cancelled
Outstanding as of, Ending	7,142

Stockholders' Equity And Stoc_5

Stockholders' Equity And Stock-Based Compensation Expense (Stock-Based Compensation Expenses) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock-based compensation expense	$ 673	$ 495
Research and development [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock-based compensation expense	389	422
General and administrative [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock-based compensation expense	$ 284	$ 73

Income Taxes (Narrative) (Detai

Income Taxes (Narrative) (Details) - USD ($)	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Income Taxes [Abstract]
Provision for income taxes	$ 0	$ 0

Commitments (Narrative) (Detail

Commitments (Narrative) (Details)	3 Months Ended
	Mar. 31, 2023 USD ($) ft²	Mar. 31, 2022 USD ($)
Operating Leased Assets [Line Items]
Cash paid for operating lease liabilities	$ 24,000	$ 41,000
Buildings [Member]
Operating Leased Assets [Line Items]
Rent expense	$ 24,000	$ 41,000
Austin, Texas [Member] | Operating Leases [Member]
Operating Leased Assets [Line Items]
Office space | ft²	6,000
Lease expiration date	Apr. 30, 2024

2020 Cash Incentive Bonus Plan

2020 Cash Incentive Bonus Plan (Narrative) (Details)		3 Months Ended	12 Months Ended
	May 01, 2023 USD ($)	Mar. 31, 2023 USD ($) item	Dec. 31, 2021 USD ($) item	Oct. 31, 2020 USD ($)
Cash Incentive Bonus Plan [Line Items]
Minimum number of valuation milestones to recognize compensation expense | item		14
Number of Valuation Milestones Achieved | item			11
Independent Directors [Member]
Cash Incentive Bonus Plan [Line Items]
Cash bonus award		$ 0
Cash Incentive Bonus Plan [Member]
Cash Incentive Bonus Plan [Line Items]
Minimum Number of Days Valuation Milestone must be achieved and maintained		20 days
Percentage of each cash bonus award associated with Valuation Milestone subject to adjustment and approval		67%
Cash Incentive Bonus Plan [Member] | Subsequent Event [Member]
Cash Incentive Bonus Plan [Line Items]
Payments authorized or made to participants under the Plan	$ 0
Cash Incentive Bonus Plan [Member] | Exceeding Performance Milestones Minimum 20 Consecutive Days [Member]
Cash Incentive Bonus Plan [Line Items]
Valuation milestone amount in market capitalization		$ 5,000,000,000
Cash Incentive Bonus Plan [Member] | First Valuation Milestone [Member]
Cash Incentive Bonus Plan [Line Items]
Cash bonus award				$ 6,500,000
Cash Incentive Bonus Plan [Member] | Second Through Eighth Valuation Milestones [Member]
Cash Incentive Bonus Plan [Line Items]
Compensation expense		0
Minimum [Member] | Cash Incentive Bonus Plan [Member]
Cash Incentive Bonus Plan [Line Items]
Valuation milestone amount in market capitalization		200,000,000
Minimum [Member] | Cash Incentive Bonus Plan [Member] | Exceeds $5 Billion Market Capitalization For No Less Than 20 Consecutive Trading Days [Member]
Cash Incentive Bonus Plan [Line Items]
Cash bonus award		111,400,000
Minimum [Member] | Cash Incentive Bonus Plan [Member] | Second Through Eighth Valuation Milestones [Member]
Cash Incentive Bonus Plan [Line Items]
Cash bonus award			$ 74,900,000
Maximum [Member] | Cash Incentive Bonus Plan [Member]
Cash Incentive Bonus Plan [Line Items]
Valuation milestone amount in market capitalization		5,000,000,000
Maximum [Member] | Cash Incentive Bonus Plan [Member] | Exceeds $5 Billion Market Capitalization For No Less Than 20 Consecutive Trading Days [Member]
Cash Incentive Bonus Plan [Line Items]
Cash bonus award		$ 289,700,000
Maximum [Member] | Cash Incentive Bonus Plan [Member] | Second Through Eighth Valuation Milestones [Member]
Cash Incentive Bonus Plan [Line Items]
Cash bonus award			$ 202,300,000

Contingencies (Narrative) (Deta

Contingencies (Narrative) (Details) - item			2 Months Ended
	Jun. 30, 2022	Nov. 04, 2021	Oct. 26, 2021
Violations of the federal securities laws [Member]
Loss Contingencies [Line Items]
Putative class action lawsuits			4
Number of class actions converted to case	1
Shareholder derivative actions [Member]
Loss Contingencies [Line Items]
Putative class action lawsuits		3