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Document And Entity Information - shares	6 Months Ended
Document And Entity Information - shares	Jun. 30, 2020	Aug. 06, 2020
Document And Entity Information [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Jun. 30, 2020
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		24,919,333
Amendment Flag	false
Entity Central Index Key	0001069530
Document Fiscal Period Focus	Q2
Document Fiscal Year Focus	2020
Current Fiscal Year End Date	--12-31

Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Current assets:
Cash and cash equivalents	$ 25,254	$ 23,081
Other current assets	186	268
Total current assets	25,440	23,349
Operating lease right-of-use assets	45	90
Property and equipment, net	13	47
Total assets	25,498	23,486
Current liabilities:
Accounts payable	416	453
Accrued development expense	755	777
Accrued compensation and benefits	84	58
Operating lease liabilities, current	45	90
Other current liabilities	14	9
Total current liabilities	1,314	1,387
Total liabilities	1,314	1,387
Commitments and contingencies
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; 24,919,333 and 21,841,810 shares issued and outstanding at June 30, 2020 and December 31, 2019, respectively	25	22
Additional paid-in capital	195,032	190,664
Accumulated deficit	(170,873)	(168,587)
Total stockholders' equity	24,184	22,099
Total liabilities and stockholders' equity	$ 25,498	$ 23,486

Balance Sheets (Parenthetical) - $ / shares	Jun. 30, 2020	Dec. 31, 2019
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	24,919,333	21,841,810
Common stock, shares outstanding	24,919,333	21,841,810

Statements Of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Operating expenses:
Research and development, net of grant reimbursement	$ 591	$ 308	$ 1,135	$ 882
General and administrative	818	845	1,596	1,722
Gain on sale of property and equipment	(246)		(346)
Total operating expenses	1,163	1,153	2,385	2,604
Operating loss	(1,163)	(1,153)	(2,385)	(2,604)
Interest income	27	94	99	186
Net loss	$ (1,136)	$ (1,059)	$ (2,286)	$ (2,418)
Net loss per share, basic and diluted	$ (0.05)	$ (0.06)	$ (0.09)	$ (0.14)
Shares used in computing net loss per share, basic and diluted	24,779	17,162	24,630	17,162

Statements Of Cash Flows - USD ($)	6 Months Ended
Statements Of Cash Flows - USD ($)	Jun. 30, 2020	Jun. 30, 2019
Cash flows from operating activities:
Net loss	$ (2,286,000)	$ (2,418,000)
Adjustments to reconcile net loss to net cash used in operating activities:
Non-cash stock-based compensation	522,000	673,000
Depreciation and amortization	20,000	30,000
Gain on sale of property and equipment	(346,000)
Changes in operating assets and liabilities:
Other current assets	82,000	184,000
Accounts payable	(37,000)	300,000
Accrued development expense	(22,000)	23,000
Accrued compensation and benefits	26,000	(1,000)
Other current liabilities	5,000	14,000
Net cash used in operating activities	(2,036,000)	(1,195,000)
Cash flows from investing activities:
Purchases of property and equipment		(18,000)
Proceeds from sale of property and equipment	360,000	0
Net cash provided by / (used in) investing activities	360,000	(18,000)
Cash flows from financing activities:
Issuance costs from 2018 sale of common stock and warrants		(60,000)
Proceeds from exercise of common stock warrants, net	3,849,000
Net cash provided by / (used in) financing activities	3,849,000	(60,000)
Net increase / (decrease) in cash and cash equivalents	2,173,000	(1,273,000)
Cash and cash equivalents at beginning of period	23,081,000	19,807,000
Cash and cash equivalents at end of period	$ 25,254,000	$ 18,534,000

Significant Accounting Policies

6 Months Ended

Jun. 30, 2020

Significant Accounting Policies [Abstract]

Significant Accounting Policies

Note 2. Significant Accounting Policies

Use of Estimates

The Company makes estimates and assumptions in preparing its 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 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 agreements, research collaborations and investments. 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 funds, certificates of deposits, and treasury bills. The Company maintains its investments 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 investments, 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 investments 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 and Level 2 inputs at December 31, 2019. A certificate of deposit totaling $13.0 million at December 31, 2019 was included within cash equivalents as a Level 2 input. The fair value of cash and cash equivalents was based on Level 1 inputs at June 30, 2020.

Proceeds from Grants

During the three months ended June 30, 2020 and 2019, the Company received reimbursements totaling $1.1 million and $1.4 million pursuant to National Institutes of Health (“NIH”) research grants, respectively. During the six months ended June 30, 2020 and 2019, the Company received reimbursements totaling $2.4 million and $2.2 million pursuant to NIH research grants, respectively. The Company records the proceeds from these grants as reductions to its research and development expenses.

Non-cash 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				Six months ended
	June 30,				June 30,
	2020		2019		2020		2019
Numerator:
Net loss	$	(1,136)	$	(1,059)	$	(2,286)	$	(2,418)
Denominator:
Shares used in computing net loss per share, basic and diluted		24,779		17,162		24,630		17,162
Net loss per share, basic and diluted	$	(0.05)	$	(0.06)	$	(0.09)	$	(0.14)

Dilutive common stock options excluded from net loss per share, diluted		2,294		2,960		2,177		2,962
Common stock warrants excluded from net loss per share, diluted		1,427		9,127		1,427		9,127

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.

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 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.

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.

Right-of-use Asset and Liability

The Company has a single non-cancelable operating lease for approximately 6,000 square feet of office space in Austin, Texas that expires on December 31, 2020, which is used for the development of novel drugs.

The Company recognize 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, in the statements of financial position. The Company utilized a discount rate of 5.5% to determine the present value of the future lease payments which represents the Company’s incremental borrowing rate.

The Company recorded a reduction of the lease liability and an offsetting reduction in the right-of-use assets of $22,500 during the three months ended June 30, 2020 and 2019. The Company recorded a reduction of the lease liability and an offsetting reduction in the right-of-use assets of $45,000 during the six months ended June 30, 2020 and 2019. See additional information regarding leases in Note 5 – Commitments.

Stockholders' Equity And Stock-Based Compensation Expense

6 Months Ended

Jun. 30, 2020

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 Six Months Ended June 30, 2020 and 2019

During the six months ended June 30, 2020 and 2019, the Company’s common stock outstanding and stockholders’ equity changed as follows:



	Common Stock	Stockholders' equity (in thousands)
Balance at December 31, 2018	17,219,300	$	19,628
Non-cash stock-based compensation for:
Stock options for employees	—		342
Stock options for non-employees	—		2
Issuance costs from sale 2018 sale of common stock and warrants	—		(60)
Net loss	—		(1,359)
Balance at March 30, 2019	17,219,300	$	18,553

Non-cash stock-based compensation for:
Stock options for employees	—		328
Stock options for non-employees	—		1
Net loss	—		(1,059)
Balance at June 30, 2019	17,219,300	$	17,823


Balance at December 31, 2019	21,841,810	$	22,099
Non-cash 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 30, 2020	24,729,902	$	24,832

Non-cash stock-based compensation for:
Stock options for employees	—		249
Stock options for non-employees	—		3
Proceeds from exercise of common stock warrants	189,431		236
Net loss	—		(1,136)
Balance at June 30, 2020	24,919,333	$	24,184

Subsequent to June 30, 2020, a total of 10,312 stock options were exercised for gross proceeds to the Company totaling $13,000.

At-the-Market (ATM) 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 six months ended June 30, 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. As of June 30, 2020, 1.4 million warrants remain outstanding, each with a strike price of $1.25 per share. Subject to certain ownership limitations described in the warrants, the warrants will remain exercisable until expiration on February 17, 2021. The warrants will be exercisable on a “cashless” basis in certain circumstances, including while there is no effective registration statement registering the shares of common stock issuable upon exercise of the warrants at any time until the expiry of the warrants. Such registration statement was declared effective by the SEC on January 30, 2019. The warrants provide that holders will have the right to participate in any rights offering or distribution of assets together with the holders of common stock on an as-exercised basis.

During the three months ended June 30, 2020, the Company received proceeds of $0.2 million from the exercise of 0.2 million warrants. During the six months ended June 30, 2020, the Company received proceeds of $3.8 million from the exercise of 3.1 million warrants. There were no warrants exercised during the three and six months ended June 30, 2019.

Stock Option and Performance Award Activity in 2020

During the six months ended June 30, 2020, 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, 2019	3,210,965	138,055
Options granted	25,000	—
Options exercised	—	—
Options forfeited/canceled	(70,093)	—
Outstanding as of June 30, 2020	3,165,872	138,055

The weighted average exercise price of options outstanding at June 30, 2020 was $12.29. As outstanding options vest over the current remaining vesting period of 2.3 years, the Company expects to recognize non-cash expense of $1.7 million. If and when outstanding Performance Awards vest, the Company will recognize non-cash expense of $2.3 million over the implicit service period.

Stock-based Compensation Expense in 2020

During the three and six months ended June 30, 2020 and 2019, the Company’s non-cash stock-based compensation expenses were as follows (in thousands):



	Three months ended				Six months ended
	June 30,				June 30,
	2020		2019		2020		2019
Research and development	$	111	$	135	$	226	$	272

General and administrative		141		194		296		401

Total non-cash stock-based compensation expense	$	252	$	329	$	522	$	673

2018 Equity Incentive Plan

In January 2018, the Company’s Board of Directors approved the Company’s 2018 Omnibus Incentive Plan (the “2018 Plan”). The Company’s Board of Directors or a designated committee of the Board of Directors 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.

Recently Issued Accounting Pronouncements	6 Months Ended
Recently Issued Accounting Pronouncements	Jun. 30, 2020
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, and is applicable for the Company in fiscal 2021. Early adoption is permitted. The Company does not anticipate that this guidance will have a material impact on its financial statements. In November 2018, the FASB issued ASU No. 2018-18, Collaborative Arrangements (Topic 808): Clarifying the Interaction Between Topic 808 and Topic 606. The amendments in this update provide guidance on how to assess whether certain transactions between collaborative arrangement participants should be accounted for within the revenue recognition standard. The amendments in this update are effective for interim and annual periods for the Company beginning on January 1, 2020. The adoption of this guidance did not have a material impact on its financial statements. In August 2018, the FASB issued ASU No. 2018-13, Fair Value Measurement (Topic 820) - Disclosure Framework - Changes to the Disclosure Requirements for Fair Value Measurement, which is designed to improve the effectiveness of disclosures by removing, modifying and adding disclosures related to fair value measurements. ASU 2018-13 is effective for fiscal years beginning after December 15, 2019, including interim periods within those fiscal years. The adoption of ASU 2018-13 did not have a material impact on its financial statements.

- Definition

The entire disclosure for change in accounting principle. Includes, but is not limited to, nature, reason, and method of adopting amendment to accounting standards or other change in accounting principle.

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-Subparagraph (e)(2)

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 65
-Paragraph 8
-Subparagraph (e)(3)

+ Details

Significant Accounting Policies (Policy)

6 Months Ended

Jun. 30, 2020

Significant Accounting Policies [Abstract]

Use Of Estimates

Use of Estimates

Cash And Cash Equivalents And Concentration Of Credit Risk

Cash and Cash Equivalents and Concentration of Credit Risk

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 3 includes unobservable inputs that are supported by little or no market activity. The Company does not have any investments where the fair value is based on Level 3 inputs.

Proceeds From Grants

Proceeds from Grants

Non-Cash Stock-Based Compensation

Non-cash Stock-based Compensation

Net Loss Per Share

Net Loss per Share

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				Six months ended
	June 30,				June 30,
	2020		2019		2020		2019
Numerator:
Net loss	$	(1,136)	$	(1,059)	$	(2,286)	$	(2,418)
Denominator:
Shares used in computing net loss per share, basic and diluted		24,779		17,162		24,630		17,162
Net loss per share, basic and diluted	$	(0.05)	$	(0.06)	$	(0.09)	$	(0.14)

Dilutive common stock options excluded from net loss per share, diluted		2,294		2,960		2,177		2,962
Common stock warrants excluded from net loss per share, diluted		1,427		9,127		1,427		9,127

Fair Value Of Financial Instruments

Fair Value of Financial Instruments

Income Taxes

Research Contract Costs And Accruals

Research Contract Costs and Accruals

Right-Of-Use Asset And Liability

Right-of-use Asset and Liability

Significant Accounting Policies (Tables)

6 Months Ended

Jun. 30, 2020

Significant Accounting Policies [Abstract]

Numerators And Denominators In The Calculation Of Basic And Diluted Net Loss Per Share



	Three months ended				Six months ended
	June 30,				June 30,
	2020		2019		2020		2019
Numerator:
Net loss	$	(1,136)	$	(1,059)	$	(2,286)	$	(2,418)
Denominator:
Shares used in computing net loss per share, basic and diluted		24,779		17,162		24,630		17,162
Net loss per share, basic and diluted	$	(0.05)	$	(0.06)	$	(0.09)	$	(0.14)

Dilutive common stock options excluded from net loss per share, diluted		2,294		2,960		2,177		2,962
Common stock warrants excluded from net loss per share, diluted		1,427		9,127		1,427		9,127

Stockholders' Equity And Stock-Based Compensation Expense (Tables)

6 Months Ended

Jun. 30, 2020

Stockholders' Equity And Stock-Based Compensation Expense [Abstract]

Common Stock Outstanding and Stockholders' Equity



	Common Stock	Stockholders' equity (in thousands)
Balance at December 31, 2018	17,219,300	$	19,628
Non-cash stock-based compensation for:
Stock options for employees	—		342
Stock options for non-employees	—		2
Issuance costs from sale 2018 sale of common stock and warrants	—		(60)
Net loss	—		(1,359)
Balance at March 30, 2019	17,219,300	$	18,553

Non-cash stock-based compensation for:
Stock options for employees	—		328
Stock options for non-employees	—		1
Net loss	—		(1,059)
Balance at June 30, 2019	17,219,300	$	17,823


Balance at December 31, 2019	21,841,810	$	22,099
Non-cash 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 30, 2020	24,729,902	$	24,832

Non-cash stock-based compensation for:
Stock options for employees	—		249
Stock options for non-employees	—		3
Proceeds from exercise of common stock warrants	189,431		236
Net loss	—		(1,136)
Balance at June 30, 2020	24,919,333	$	24,184

Stock Options And Unvested Performance Award Outstanding Activity



	Stock Options	Performance Awards
Outstanding as of December 31, 2019	3,210,965	138,055
Options granted	25,000	—
Options exercised	—	—
Options forfeited/canceled	(70,093)	—
Outstanding as of June 30, 2020	3,165,872	138,055

Non-Cash Stock-Based Compensation Expenses



	Three months ended				Six months ended
	June 30,				June 30,
	2020		2019		2020		2019
Research and development	$	111	$	135	$	226	$	272

General and administrative		141		194		296		401

Total non-cash stock-based compensation expense	$	252	$	329	$	522	$	673

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				6 Months Ended
	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2020	Jun. 30, 2019
Numerator:
Net loss	$ (1,136)	$ (1,150)	$ (1,059)	$ (1,359)	$ (2,286)	$ (2,418)
Denominator:
Shares used in computing net loss per share, basic and diluted	24,779		17,162		24,630	17,162
Net loss per share, basic and diluted	$ (0.05)		$ (0.06)		$ (0.09)	$ (0.14)
Employee Stock Option [Member]
Denominator:
Common stock shares excluded from net loss per share, diluted	2,294		2,960		2,177	2,962
Stock Warrants [Member]
Denominator:
Common stock shares excluded from net loss per share, diluted	1,427		9,127		1,427	9,127

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References

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+ Details

Stockholders' Equity And Stock-Based Compensation Expense (Narrative) (Details) - USD ($) $ / shares in Units, $ in Thousands				3 Months Ended		6 Months Ended
	Jul. 01, 2020	Mar. 27, 2020	Jan. 31, 2018	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019	Aug. 31, 2018
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Proceeds from exercise of warrants						$ 3,849
Non-cash stock-based compensation expense				$ 252	$ 329	$ 522	$ 673
Par value per share				$ 0.001		$ 0.001		$ 0.001
Warrants [Member]
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Remaining outstanding				1,400,000		1,400,000
Strike price						$ 1.25
Expiration date						Feb. 17, 2021
Proceeds from exercise of warrants				$ 200		$ 3,800
Number of warrants exercised				200,000	0	3,100,000	0
Warrants [Member] \| Maximum [Member]
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Aggregate shares to be purchased									9,100,000
ATM [Member]
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Percentage of commission in ATM offering		3.00%
Number of common stock sold shares						0
ATM [Member] \| Maximum [Member]
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Aggregate offering price		$ 100,000
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			1,000,000
Subsequent Event [Member]
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Number of Options, Exercised	10,312
Proceeds from stock options exercised	$ 13,000
Employee Stock Option [Member]
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Number of Options, Exercised
Employee Stock Option [Member] \| Stock Option And Performance Award Activity In 2019 Plan [Member]
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Weighted average exercise price or options				$ 12.29		$ 12.29
Vesting period of stock options						2 years 3 months 18 days
Non-cash stock-based compensation expense						$ 1,700
Performance Awards [Member]
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Number of Options, Exercised
Performance Awards [Member] \| Stock Option And Performance Award Activity In 2019 Plan [Member]
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Non-cash stock-based compensation expense						$ 2,300

Stockholders' Equity And Stock-Based Compensation Expense (Common Stock Outstanding and Stockholders' Equity) (Details) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2020	Jun. 30, 2019
Common Stock, Beginning balance	24,729,902	21,841,810	17,219,300	17,219,300	21,841,810	17,219,300
Common Stock, Proceeds from exercise of common stock warrants	189,431	2,888,092
Common Stock, Issuance costs from sale 2018 sale of common stock and warrants
Common Stock, Net loss
Common Stock, Ending balance	24,919,333	24,729,902	17,219,300	17,219,300	24,919,333	17,219,300
Stockholders' equity, Beginning balance	$ 24,832	$ 22,099	$ 18,553	$ 19,628	$ 22,099	$ 19,628
Stockholders' equity, Non-cash stock-based compensation for:					522	673
Stockholders' equity, Proceeds from exercise of common stock warrants	236	3,613
Stockholders' Equity, Issuance of common stock and warrants, net of issuance costs				(60)
Net loss	(1,136)	(1,150)	(1,059)	(1,359)	(2,286)	(2,418)
Stockholders' equity, Ending balance	$ 24,184	$ 24,832	$ 17,823	$ 18,553	$ 24,184	$ 17,823
Employee Stock Option [Member]
Common Stock, Non-cash stock-based compensation for:
Stockholders' equity, Non-cash stock-based compensation for:	$ 249	$ 261	$ 328	$ 342
Non-Employee Stock Options [Member]
Common Stock, Non-cash stock-based compensation for:
Stockholders' equity, Non-cash stock-based compensation for:	$ 3	$ 9	$ 1	$ 2

General And Liquidity	6 Months Ended
General And Liquidity	Jun. 30, 2020
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 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 and six months ended June 30, 2020 are not necessarily indicative of the results that may be expected for any other interim period or for the year 2020. 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, 2019. Liquidity The Company has incurred significant net losses and negative cash flows since inception, and as a result has an accumulated deficit of $170.9 million at June 30, 2020. 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. The recent, 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 August 12, 2020. 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.

Income Taxes	6 Months Ended
Income Taxes	Jun. 30, 2020
Income Taxes [Abstract]
Income Taxes	Note 4. Income Taxes The Company did not provide for income taxes during the three and six months ended June 30, 2020, because it has projected a net loss for the full year 2020 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 and six months ended June 30, 2019.

Collaboration Agreement	6 Months Ended
Collaboration Agreement	Jun. 30, 2020
Collaboration Agreement [Abstract]
Collaboration Agreement	Note 6. Collaboration Agreement The Company had formerly entered into a Development and License Agreement (the “License Agreement”) with Durect Corporation around certain controlled-release technology. In March 2019, the Company gave notice of termination for such License Agreement. This and other actions effectively ended the Company’s development of any product candidates related to such technology.

Sale Of Property And Equipment	6 Months Ended
Sale Of Property And Equipment	Jun. 30, 2020
Sale Of Property And Equipment [Abstract]
Sale Of Property And Equipment	Note 7. Sale of Property and Equipment During the three months ended June 30, 2020, the Company sold surplus manufacturing equipment to an independent third party and received proceeds totaling $260,000. During the six months ended June 30, 2020, the Company sold surplus manufacturing equipment to an independent third party and received proceeds totaling $360,000. The original cost of the property and equipment was $892,000 and accumulated depreciation was $878,000, resulting a gain on sale of property and equipment of $246,000 and $346,000, respectively, during the three and six months ended June 30, 2020. There were no sales of property and equipment during the three and six months ended June 30, 2019.

General And Liquidity (Narrative) (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
General And Liquidity [Abstract]
Accumulated deficit	$ 170,873	$ 168,587

Significant Accounting Policies (Narrative) (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020 USD ($) ft²	Jun. 30, 2019 USD ($)	Jun. 30, 2020 USD ($) ft²	Jun. 30, 2019 USD ($)	Dec. 31, 2019 USD ($)
Summary Of Significant Accounting Policies [Line Items]
Certificates of deposit					$ 13,000
Reimbursement from National Institutes of Health research grants	$ 1,100	$ 1,400	$ 2,400	$ 2,200
Leases, discount rate	5.50%		5.50%
Reduction of non-current lease liability and offsetting reduction in right-of-use assets	$ 22,500	$ 22,500	$ 45,000	$ 45,000
Austin [Member]
Summary Of Significant Accounting Policies [Line Items]
Office space \| ft²	6,000		6,000
Lease expiration date			Dec. 31, 2020

Stockholders' Equity And Stock-Based Compensation Expense (Stock Option And Unvested Performance Award Outstanding Activity) (Details)	6 Months Ended
	Jun. 30, 2020 shares
Employee Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Outstanding as of, beginning	3,210,965
Options granted	25,000
Options exercised
Options forfeited/canceled	(70,093)
Outstanding as of, ending	3,165,872
Performance Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Outstanding as of, beginning	138,055
Options granted
Options exercised
Options forfeited/canceled
Outstanding as of, ending	138,055

Income Taxes (Narrative) (Details) - USD ($)	3 Months Ended		6 Months Ended
Income Taxes (Narrative) (Details) - USD ($)	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Income Taxes [Abstract]
Provision for income taxes	$ 0	$ 0	$ 0	$ 0

Commitments (Narrative) (Details) $ in Thousands	3 Months Ended		6 Months Ended
Commitments (Narrative) (Details) $ in Thousands	Jun. 30, 2020 USD ($) ft²	Jun. 30, 2019 USD ($)	Jun. 30, 2020 USD ($) ft²	Jun. 30, 2019 USD ($)
Building [Member]
Operating Leased Assets [Line Items]
Rent \| $	$ 25	$ 24	$ 50	$ 48
Austin [Member]
Operating Leased Assets [Line Items]
Office space \| ft²	6,000		6,000
Lease expiration date			Dec. 31, 2020

Commitments (Minimum Lease Payments) (Details) $ in Thousands	Jun. 30, 2020 USD ($)
Commitments [Abstract]
For the year ending December 31, 2020	$ 50
Total future minimum lease payments	50
Lease: imputed interest	(5)
Total	$ 45