Cassava Sciences (SAVA) 10-Q 29 Apr 21 2021 Q1 Quarterly report Financial data

Document And Entity Information

Document And Entity Information - shares	3 Months Ended
	Mar. 31, 2021	Apr. 23, 2021
Document And Entity Information [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Fiscal Period Focus	Q1
Document Period End Date	Mar. 31, 2021
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	7801 N. Capital of Texas Highway
Entity Address, Address Line Two	Suite 260
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	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		40,008,654
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2021
Entity Central Index Key	0001069530

Condensed Balance Sheets

Condensed Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 282,192	$ 93,506
Other current assets	1,574	488
Total current assets	283,766	93,994
Operating lease right-of-use assets	274	295
Property and equipment, net	10	11
Total assets	284,050	94,300
Current liabilities:
Accounts payable	864	911
Accrued development expense	1,553	719
Accrued compensation and benefits	99	83
Operating lease liabilities, current	84	58
Other current liabilities	50	94
Total current liabilities	2,650	1,865
Operating lease liabilities, non-current	213	235
Total liabilities	2,863	2,100
Commitments and contingencies (Notes 5 and 7)
Stockholders' equity:
Preferred stock, $.001 par value; 10,000,000 shares authorized, none issued and outstanding
Common stock, $.001 par value; 120,000,000 shares authorized; 40,008,654 and 35,237,987 shares issued and outstanding at March 31, 2021 and December 31, 2020, respectively	40	35
Additional paid-in capital	459,594	267,086
Accumulated deficit	(178,447)	(174,921)
Total stockholders' equity	281,187	92,200
Total liabilities and stockholders' equity	$ 284,050	$ 94,300

Condensed Balance Sheets (Paren

Condensed Balance Sheets (Parenthetical) - $ / shares	Mar. 31, 2021	Dec. 31, 2020
Condensed 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	40,008,654	35,237,987
Common stock, shares outstanding	40,008,654	35,237,987

Condensed Statements Of Operati

Condensed Statements Of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Operating expenses:
Research and development, net of grant reimbursement	$ 2,529	$ 544
General and administrative	1,004	778
Gain on sale of property and equipment		(100)
Total operating expenses	3,533	1,222
Operating loss	(3,533)	(1,222)
Interest income	7	72
Net loss	$ (3,526)	$ (1,150)
Net loss per share, basic and diluted	$ (0.09)	$ (0.05)
Shares used in computing net loss per share, basic and diluted	37,721	24,481

Condensed Statements Of Cash Fl

Condensed Statements Of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Cash flows from operating activities:
Net loss	$ (3,526)	$ (1,150)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation	250	270
Depreciation and amortization	1	14
Gain on sale of property and equipment		(100)
Changes in operating assets and liabilities:
Other current assets	185	(9)
Operating lease right-of-use assets and liabilities	25
Accounts payable	(47)	155
Accrued development expense	834	(390)
Accrued compensation and benefits	16	14
Other current liabilities	(44)	2
Net cash used in operating activities	(2,306)	(1,194)
Cash flows from investing activities:
Proceeds from sale of property and equipment		100
Net cash provided by investing activities		100
Cash flows from financing activities:
Proceeds from exercise of stock options	475
Proceeds from exercise of common stock warrants	692	3,613
Proceeds from registered direct offering, net of issuance costs	189,825
Net cash provided by financing activities	190,992	3,613
Net increase in cash and cash equivalents	188,686	2,519
Cash and cash equivalents at beginning of period	93,506	23,081
Cash and cash equivalents at end of period	282,192	$ 25,600
Supplemental cash flow information:
Receivable from exercise of stock options	$ 1,271

General And Liquidity

General And Liquidity	3 Months Ended
	Mar. 31, 2021
General And Liquidity [Abstract]
General And Liquidity	Note 1. General and Liquidity  Cassava Sciences, Inc. (the “Company”) discovers and develops 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 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. Accordingly, the condensed financial statements do not include all of the information and footnotes required by GAAP for complete 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, 2021 are not necessarily indicative of the results that may be expected for any other interim period or for the year 2021 . For further information, refer to the financial statements and footnotes thereto included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2020.  Coronavirus Disease 2019 (COVID-19)  The widespread outbreak of a novel infectious disease called Coronavirus Disease 2019, or COVID-19, has not significantly impacted the Company’s operations or financial condition as of April 2 9 , 2021 . However, this pandemic has created a dynamic and uncertain situation in the national economy. The Company continues to closely monitor the latest information to make timely, informed business decisions and public disclosures regarding the potential impact of pandemic on its operations and financial condition. The scope of pandemic is unprecedented and its long-term impact on the Company’s operations and financial condition cannot be reasonably estimated at this time.  Liquidity  The Company has incurred significant net losses and negative cash flows since inception, and as a result has an accumulated deficit of $178.4 million at March 31, 2021. 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, 2021
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 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 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, certificates of deposits, and treasury bills. The Company maintains its cash and cash equivalents at one financial institution.  Fair Value Measurements  The Company reports its cash and cash equivalents at fair value as Level 1, Level 2 or Level 3 using the following inputs:  · Level 1 includes quoted prices in active markets. The Company bases the fair value of its money market funds on Level 1 inputs. · 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 bases the fair value of its certificates of deposit 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, 2021 and December 31, 2020.  Proceeds from Grants  During the three months ended March 31, 2021 and 2020, the Company received reimbursements totaling $0.6 million and $1.3 million pursuant to National Institutes of Health (“NIH”) research grants, respectively. 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. 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 and warrants. There is no difference between the Company’s net loss and comprehensive loss.  The Company included the following in the calculation of basic and diluted net loss per share (in thousands, except per share data):        Three months ended March 31,  2021 2020  Numerator:  Net loss $ (3,526) $ (1,150)  Denominator:  Shares used in computing net loss per share, basic and diluted 37,721 24,481  Net loss per share, basic and diluted $ (0.09) $ (0.05)   Dilutive common stock options excluded from net loss per share, diluted 2,121 1,561  Common stock warrants excluded from net loss per share, diluted — 1,616   The Company excluded common stock options and warrants outstanding from the calculation of net loss per share, diluted, because the effect of including options and warrants outstanding 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, and related payments are recorded as research and development expenses as incurred. The Company records accruals for estimated ongoing research costs. When evaluating the adequacy of the 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 accrued balances at the end of any reporting period. Actual results could differ from the Company’s estimates. The Company’s historical 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 is considered probable of being met. See Note 7 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 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.  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 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.

Stockholders' Equity And Stock-

Stockholders' Equity And Stock-Based Compensation Expense	3 Months Ended
	Mar. 31, 2021
Stockholders' Equity And Stock-Based Compensation Expense [Abstract]
Stockholders' Equity And Stock-Based Compensation Expense	Note 3. Stockholders’ Equity and Stock-Based Compensation Expense  Stockholders’ Equity Activity during the Three Months Ended March 31, 2021 and 2020  During the three months ended March 31, 2021 and 2020, the Company’s common stock outstanding and stockholders’ equity changed as follows:    Common Stock Stockholders' equity (in thousands)  Balance at December 31, 2019 21,841,810 $ 22,099  Stock-based compensation for:  Stock options for employees — 261  Stock options for non-employees — 9  Proceeds from exercise of common stock warrants 2,888,092 3,613  Net loss — (1,150)  Balance at March 31, 2020 24,729,902 $ 24,832    Balance at December 31, 2020 35,237,987 $ 92,200  Stock-based compensation for:  Stock options for employees — 249  Stock options for non-employees — 1  Proceeds from exercise of common stock warrants 554,019 692  Exercise of stock options 135,015 1,746  Proceeds from registered direct offering of common stock 4,081,633 189,825  Net loss — (3,526)  Balance at March 31, 2021 40,008,654 $ 281,187  2021 Registered Direct Offering  On February 12, 2021, the Company completed a common stock offering pursuant to which certain investors purchased 4,081,633 shares of common stock at a price of $49.00 per share. Net proceeds of the offering were approximately $189.8 million after deducting offering expenses.  At-the-Market Common Stock Offering  On March 27, 2020, the Company established an at-the-market offering program (“ATM”) 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 is obligated to pay a commission of 3.0% of the gross proceeds from the sale of shares of common stock in the offering. The Company is not obligated to sell any shares in the offering.  There were no common stock sales under the ATM during the three months ended March 31, 2021 and 2020.  Common Stock Warrants  In August 2018, the Company issued warrants to purchase up to an aggregate of 9.1 million shares of its common stock in conjunction with an offering of its common stock.  During the three months ended March 31, 2021, the Company received proceeds of $0.7 million from the exercise of 0.6 million shares pursuant to warrants. During the three months ended March 31, 2020, the Company received proceeds of $3.6 million from the exercise of 2.9 million shares pursuant to warrants.  There were no remaining common stock warrants outstanding as of March 31, 2021.  Stock Option and Performance Award Activity in 2021  During the three months ended March 31, 2021, 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, 2020 2,817,504 138,055  Options granted 10,000 —  Options exercised (163,398) —  Options forfeited/canceled — —  Outstanding as of March 31, 2021 2,664,106 138,055   The weighted average exercise price of options outstanding at March 31, 2021 was $10.80 . As outstanding options vest over the current remaining vesting period of 2.0 years, the Company expects to recognize non-cash expense of $1.6 million. If and when outstanding Performance Awards vest, the Company will recognize non-cash expense of $2.3 million over the implicit service period.  During the three months ended March 31, 2021, there were 163,398 stock options exercised. Of the stock options exercised, 28,383 stock options were net settled in satisfaction of the exercise price, with no cash proceeds received. Proceeds to the Company totaled $1,746,000 , including $475,000 in cash paid and $1,271,000 recorded as receivables in other current assets at March 31, 2021 due to timing differences. All such receivables related to stock option exercises were received by the Company in April 2021.  There were no stock options exercised during the three months ended March 31, 2020.  Stock-based Compensation Expense in 2021  During the three months ended March 31, 2021 and 2020, the Company’s stock-based compensation expenses were as follows (in thousands):    Three months ended  March 31,  2021 2020  Research and development $ 120 $ 115   General and administrative 130 155   Total stock-based compensation expense $ 250 $ 270  2018 Equity Incentive Plan  In January 2018, the Company’s Board of Directors (the “Board”) approved the Company’s 2018 Omnibus Incentive Plan (the “2018 Plan”). The Board or a designated committee of the Board is responsible for administration of 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 provides for issuance of up to 1,000,000 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, 2021
Income Taxes [Abstract]
Income Taxes	Note 4. Income Taxes  The Company did not provide for income taxes during the three months ended March 31, 2021, because it has projected a net loss for the full year 2021 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, 2020. 

Commitments

Commitments	3 Months Ended
	Mar. 31, 2021
Commitments [Abstract]
Commitments	Note 5. Commitments  Right-of-use Asset and Liability  The Company has a non-cancelable operating lease for approximately 6,000 square feet of office space in Austin, Texas that expires on April 30, 2024 . Future lease payments as of March 31, 2021 are as follows (in thousands):      For the year ending December 31,  2021 $ 66  2022 102  2023 107  2024 36  Total future lease payments 311  Less: imputed interest (14)  Total $ 297  Subsequent to March 31, 2021, the Company entered into a lease agreement for an additional 3,600 square feet of office space in Austin, Texas that expires on April 30, 2022 . Future lease payments under this lease total $64,000 .  Rent expense for the three months ended March 31, 2021 and 2020 totaled $23,000 and $25,000 , respectively.  There was no cash paid for operating lease liabilities during the three months ended March 31, 2021. Cash paid for operating lease liabilities during the three months ended March 31, 2020 totaled $25,000 .  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. The Company also had non-cancellable commitments for the manufacture of simufilam totaling $817,000 at March 31, 2021.

Sale Of Property And Equipment

Sale Of Property And Equipment	3 Months Ended
	Mar. 31, 2021
Sale Of Property And Equipment [Abstract]
Sale Of Property And Equipment	Note 6. Sale of Property and Equipment  There were no sales of property and equipment during the three months ended March 31, 2021. During the three months ended March 31, 2020, the Company sold surplus manufacturing equipment to a third party and received proceeds totaling $100,000 . 

2020 Cash Incentive Bonus Plan

2020 Cash Incentive Bonus Plan	3 Months Ended
	Mar. 31, 2021
Cash Incentive Bonus Plan [Abstract]
2020 Cash Incentive Bonus Plan	 Note 7. 2020 Cash Incentive Bonus Plan  On August 26, 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, 2021.  Plan participants will be paid all earned cash bonuses in the event of a Merger Transaction.  The Company’s market capitalization for purposes of the Plan is determined based on either (1) the Company’s closing price of one share 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 59% 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 $137.4 million up to a hypothetical maximum of $322.3 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.  On October 13, 2020, the Company achieved the first Valuation Milestone. Subsequently, the Compensation Committee approved a potential cash bonus award of $7.3 million in total for all Plan participants, subject to future satisfaction of a Performance Condition.  During the three months ended March 31, 2021, the Company achieved eight Valuation Milestones triggering potential Company obligations to all Plan participants from a minimum of $59.9 million up to a hypothetical maximum of $145.0 million, to be determined by the Compensation Committee. However, no compensation expense has been 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 actual cash payments were authorized or made to participants under the Plan during the three months ended March 31, 2021. 

Recently Issued Accounting Pron

Recently Issued Accounting Pronouncements	3 Months Ended
	Mar. 31, 2021
Recently Issued Accounting Pronouncements [Abstract]
Recently Issued Accounting Pronouncements	Note 8. Recently Issued Accounting Pronouncements  In December 2019, the FASB issued Accounting Standards Update (“ASU”) No. 2019-12, Income Taxes (Topic 740) Simplifying Accounting for Income Taxes , as part of its initiative to reduce complexity in the accounting standards. The guidance amended certain disclosure requirements that had become redundant, outdated or superseded. Additionally, this guidance amends accounting for the interim period effects of changes in tax laws or rates, and simplifies aspects of the accounting for franchise taxes. The guidance is effective for annual periods beginning after December 15, 2020, including interim periods therein . The adoption of ASU 2019-12 in the first quarter of 2021 did not have a material impact on the Company’s condensed financial statements.  

Significant Accounting Polici_2

Significant Accounting Policies (Policy)	3 Months Ended
	Mar. 31, 2021
Significant Accounting Policies [Abstract]
Use Of Estimates	Use of Estimates  The Company makes estimates and assumptions in preparing its condensed 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 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, certificates of deposits, and treasury bills. The Company maintains its cash and cash equivalents at one financial institution.
Fair Value Measurements	Fair Value Measurements  The Company reports its cash and cash equivalents at fair value as Level 1, Level 2 or Level 3 using the following inputs:  · Level 1 includes quoted prices in active markets. The Company bases the fair value of its money market funds on Level 1 inputs. · 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 bases the fair value of its certificates of deposit 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, 2021 and December 31, 2020.
Proceeds From Grants	Proceeds from Grants  During the three months ended March 31, 2021 and 2020, the Company received reimbursements totaling $0.6 million and $1.3 million pursuant to National Institutes of Health (“NIH”) research grants, respectively. 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. 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 and warrants. There is no difference between the Company’s net loss and comprehensive loss.  The Company included the following in the calculation of basic and diluted net loss per share (in thousands, except per share data):        Three months ended March 31,  2021 2020  Numerator:  Net loss $ (3,526) $ (1,150)  Denominator:  Shares used in computing net loss per share, basic and diluted 37,721 24,481  Net loss per share, basic and diluted $ (0.09) $ (0.05)   Dilutive common stock options excluded from net loss per share, diluted 2,121 1,561  Common stock warrants excluded from net loss per share, diluted — 1,616   The Company excluded common stock options and warrants outstanding from the calculation of net loss per share, diluted, because the effect of including options and warrants outstanding 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, and related payments are recorded as research and development expenses as incurred. The Company records accruals for estimated ongoing research costs. When evaluating the adequacy of the 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 accrued balances at the end of any reporting period. Actual results could differ from the Company’s estimates. The Company’s historical 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 is considered probable of being met. See Note 7 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 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.
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 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, 2021
Significant Accounting Policies [Abstract]
Numerators And Denominators In The Calculation Of Basic And Diluted Net Loss Per Share	    Three months ended March 31,  2021 2020  Numerator:  Net loss $ (3,526) $ (1,150)  Denominator:  Shares used in computing net loss per share, basic and diluted 37,721 24,481  Net loss per share, basic and diluted $ (0.09) $ (0.05)   Dilutive common stock options excluded from net loss per share, diluted 2,121 1,561  Common stock warrants excluded from net loss per share, diluted — 1,616  

Stockholders' Equity And Stoc_2

Stockholders' Equity And Stock-Based Compensation Expense (Tables)	3 Months Ended
	Mar. 31, 2021
Stockholders' Equity And Stock-Based Compensation Expense [Abstract]
Common Stock Outstanding And Stockholders' Equity	  Common Stock Stockholders' equity (in thousands)  Balance at December 31, 2019 21,841,810 $ 22,099  Stock-based compensation for:  Stock options for employees — 261  Stock options for non-employees — 9  Proceeds from exercise of common stock warrants 2,888,092 3,613  Net loss — (1,150)  Balance at March 31, 2020 24,729,902 $ 24,832    Balance at December 31, 2020 35,237,987 $ 92,200  Stock-based compensation for:  Stock options for employees — 249  Stock options for non-employees — 1  Proceeds from exercise of common stock warrants 554,019 692  Exercise of stock options 135,015 1,746  Proceeds from registered direct offering of common stock 4,081,633 189,825  Net loss — (3,526)  Balance at March 31, 2021 40,008,654 $ 281,187 
Stock Options And Unvested Performance Award Outstanding Activity	  Stock Options Performance Awards  Outstanding as of December 31, 2020 2,817,504 138,055  Options granted 10,000 —  Options exercised (163,398) —  Options forfeited/canceled — —  Outstanding as of March 31, 2021 2,664,106 138,055  
Stock-Based Compensation Expense	   Three months ended  March 31,  2021 2020  Research and development $ 120 $ 115   General and administrative 130 155   Total stock-based compensation expense $ 250 $ 270  

Commitments (Tables)

Commitments (Tables)	3 Months Ended
	Mar. 31, 2021
Commitments [Abstract]
Future Minimum Lease Payments	   For the year ending December 31,  2021 $ 66  2022 102  2023 107  2024 36  Total future lease payments 311  Less: imputed interest (14)  Total $ 297  

General And Liquidity (Narrativ

General And Liquidity (Narrative) (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
General And Liquidity [Abstract]
Accumulated deficit	$ 178,447	$ 174,921

Significant Accounting Polici_4

Significant Accounting Policies (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Summary Of Significant Accounting Policies [Line Items]
Reimbursement from National Institutes of Health research grants	$ 0.6	$ 1.3
Vesting period of stock options	4 years

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, 2021	Mar. 31, 2020
Numerator:
Net loss	$ (3,526)	$ (1,150)
Denominator:
Shares used in computing net loss per share, basic and diluted	37,721	24,481
Net loss per share, basic and diluted	$ (0.09)	$ (0.05)
Stock Option [Member]
Denominator:
Common stock excluded from net loss per share, diluted	2,121	1,561
Warrants [Member]
Denominator:
Common stock excluded from net loss per share, diluted		1,616

Stockholders' Equity And Stoc_3

Stockholders' Equity And Stock-Based Compensation Expense (Narrative) (Details) - USD ($)	Feb. 12, 2021	Mar. 27, 2020	Jan. 31, 2018	Aug. 31, 2018	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020	May 05, 2020
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock options exercised					135,015
Proceeds from exercise of stock options					$ 475,000
Cash receivable recorded as other current assets					1,574,000		$ 488,000
Net proceeds from offering					189,825,000
Proceeds from exercise of warrants					$ 692,000	$ 3,613,000
Vesting period of stock options					4 years
Non-cash stock-based compensation expense					$ 250,000	270,000
Par value per share					$ 0.001		$ 0.001
2021 Registered Direct Offering [Member]
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Number of shares issued	4,081,633
Price per share	$ 49
Net proceeds from offering	$ 189,800,000
ATM [Member]
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Percentage of commission in ATM offering								3.00%
Number of shares issued					0		0
ATM [Member] | Maximum [Member]
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Aggregate offering price		$ 100,000,000
Common Stock Warrants [Member] | Warrants [Member]
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Number of shares issued				9,100,000
Proceeds from exercise of warrants					$ 700,000	$ 3,600,000
Number of warrants exercised					600,000	2,900,000
Number of warrants outstanding					0
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			1,000,000
Stock Option [Member]
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock options exercised					163,398
Stock options exercised, net settled in satisfaction of the exercise price					28,383
Proceeds from stock options exercised net settled in satisfaction of the exercise price					$ 0
Stock Option [Member] | Stock Option And Performance Award [Member]
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Proceeds from exercise of stock options					1,746,000	$ 0
Cash					475,000
Cash receivable recorded as other current assets					$ 1,271,000
Weighted average exercise price or options					$ 10.80
Vesting period of stock options					2 years
Non-cash stock-based compensation expense					$ 1,600,000
Performance Award [Member] | Stock Option And Performance Award [Member]
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Non-cash stock-based compensation expense					$ 2,300,000

Stockholders' Equity And Stoc_4

Stockholders' Equity And Stock-Based Compensation Expense (Common Stock Outstanding And Stockholders' Equity) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Common Stock, Beginning balance	35,237,987	21,841,810
Common Stock, Proceeds from exercise of common stock warrants	554,019	2,888,092
Common Stock, Exercise of stock options	135,015
Common Stock, Proceeds from registered direct offering of common stock	4,081,633
Net loss
Common Stock, Ending balance	40,008,654	24,729,902
Stockholders' equity, Beginning balance	$ 92,200	$ 22,099
Stockholders' equity, Stock-based compensation for:	250	270
Stockholders' equity, Proceeds from exercise of common stock warrants	692	3,613
Stockholders' equity, Exercise of stock options	1,746
Stockholders' equity, Proceeds from registered direct offering of common stock	189,825
Net loss	(3,526)	(1,150)
Stockholders' equity, Ending balance	$ 281,187	$ 24,832
Stock Option [Member]
Common Stock, Stock-based compensation for:
Common Stock, Exercise of stock options	163,398
Stockholders' equity, Stock-based compensation for:	$ 249	$ 261
Non-Employee Stock Options [Member]
Common Stock, Stock-based compensation for:
Stockholders' equity, Stock-based compensation for:	$ 1	$ 9

Stockholders' Equity And Stoc_5

Stockholders' Equity And Stock-Based Compensation Expense (Stock Options And Unvested Performance Award Outstanding Activity) (Details)	3 Months Ended
	Mar. 31, 2021shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options exercised	(135,015)
Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Outstanding as of, Beginning	2,817,504
Options granted	10,000
Options exercised	(163,398)
Options forfeited/canceled
Outstanding as of, Ending	2,664,106
Performance Award [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Outstanding as of, Beginning	138,055
Options granted
Options exercised
Options forfeited/cancelled
Outstanding as of, Ending	138,055

Stockholders' Equity And Stoc_6

Stockholders' Equity And Stock-Based Compensation Expense (Stock-Based Compensation Expenses) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock-based compensation expense	$ 250	$ 270
Research and development [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock-based compensation expense	120	115
General and administrative [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock-based compensation expense	$ 130	$ 155

Income Taxes (Narrative) (Detai

Income Taxes (Narrative) (Details)	3 Months Ended
	Mar. 31, 2020USD ($)
Income Taxes [Abstract]
Provision for income taxes	$ 0

Commitments (Narrative) (Detail

Commitments (Narrative) (Details) $ in Thousands	Apr. 01, 2021USD ($)ft²	Sep. 04, 2020	Mar. 31, 2021USD ($)ft²	Mar. 31, 2020USD ($)
Operating Leased Assets [Line Items]
Future lease payments			$ 311
Cash paid for operating lease liabilities				$ 25
Non-cancellable commitments			817
Building [Member]
Operating Leased Assets [Line Items]
Rent expense			$ 23	$ 25
Austin [Member]
Operating Leased Assets [Line Items]
Office space | ft²			6,000
Lease expiration date		Apr. 30, 2024
Austin [Member] | Subsequent Event [Member]
Operating Leased Assets [Line Items]
Office space | ft²	3,600
Lease expiration date	Apr. 30, 2022
Future lease payments	$ 64

Commitments (Future Minimum Lea

Commitments (Future Minimum Lease Payments) (Details) $ in Thousands	Mar. 31, 2021USD ($)
For the year ending December 31,
2021	$ 66
2022	102
2023	107
2024	36
Total future lease payments	311
Less: imputed interest	(14)
Total	$ 297

Sale Of Property And Equipment

Sale Of Property And Equipment (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Sale Of Property And Equipment [Abstract]
Proceeds from sale of property and equipment		$ 100

2020 Cash Incentive Bonus Plan

2020 Cash Incentive Bonus Plan (Narrative) (Details) - Cash Incentive Bonus Plan [Member] - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Oct. 13, 2020
Cash Incentive Bonus Plan [Line Items]
Percentage of each cash bonus award associated with Valuation Milestone subject to adjustment and approval	59.00%
Cash bonus award		$ 7.3
Payments authorized or made to participants under the Plan	$ 0
Eighth Valuation Milestones [Member]
Cash Incentive Bonus Plan [Line Items]
Compensation expense	0
Minimum [Member]
Cash Incentive Bonus Plan [Line Items]
Valuation milestone amount in market capitalization	200
Minimum [Member] | Exceeds $5 Billion Market Capitalization For No Less Than 20 Consecutive Trading Days [Member]
Cash Incentive Bonus Plan [Line Items]
Cash bonus award	137.4
Minimum [Member] | Eighth Valuation Milestones [Member]
Cash Incentive Bonus Plan [Line Items]
Cash bonus award	59.9
Maximum [Member]
Cash Incentive Bonus Plan [Line Items]
Valuation milestone amount in market capitalization	5,000
Maximum [Member] | Exceeds $5 Billion Market Capitalization For No Less Than 20 Consecutive Trading Days [Member]
Cash Incentive Bonus Plan [Line Items]
Cash bonus award	322.3
Maximum [Member] | Eighth Valuation Milestones [Member]
Cash Incentive Bonus Plan [Line Items]
Cash bonus award	$ 145