CervoMed (CRVO) 10-Q 7 May 21 2021 Q1 Quarterly report Financial data

Document And Entity Information

Document And Entity Information - shares	3 Months Ended
	Mar. 31, 2021	May 07, 2021
Document Information [Line Items]
Entity Registrant Name	Diffusion Pharmaceuticals Inc.
Entity Central Index Key	0001053691
Trading Symbol	dffn
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Current Reporting Status	Yes
Entity Emerging Growth Company	false
Entity Small Business	true
Entity Interactive Data Current	Yes
Entity Common Stock, Shares Outstanding (in shares)		101,903,979
Entity Shell Company	false
Document Type	10-Q
Document Period End Date	Mar. 31, 2021
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q1
Amendment Flag	false
Title of 12(b) Security	Common Stock, par value $0.001 per share

Consolidated Balance Sheets (Cu

Consolidated Balance Sheets (Current Period Unaudited) - USD ($)	Mar. 31, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 46,634,977	$ 18,515,595
Prepaid expenses, deposits and other current assets	678,693	260,825
Total current assets	47,313,670	18,776,420
Property and equipment, net	124,751	149,198
Intangible asset	8,639,000	8,639,000
Right of use asset	120,110	149,162
Other assets	15,580	15,771
Total assets	56,213,111	27,729,551
Current liabilities:
Accounts payable	952,909	545,844
Accrued expenses and other current liabilities	1,048,904	1,776,470
Current operating lease liability	111,291	113,469
Total current liabilities	2,113,104	2,435,783
Deferred income taxes	443,893	443,893
Noncurrent operating lease liability	8,819	35,693
Total liabilities	2,565,816	2,915,369
Commitments and Contingencies (Note 7)
Stockholders’ Equity:
Common stock, $0.001 par value: 1,000,000,000 shares authorized: 101,903,979 and 64,015,441 shares issued and outstanding at March 31, 2021 and December 31, 2020, respectively	101,904	64,016
Additional paid-in capital	164,098,694	130,659,550
Accumulated deficit	(110,553,303)	(105,909,384)
Total stockholders' equity	53,647,295	24,814,182
Total liabilities and stockholders' equity	$ 56,213,111	$ 27,729,551

Consolidated Balance Sheets (_2

Consolidated Balance Sheets (Current Period Unaudited) (Parentheticals) - $ / shares	Mar. 31, 2021	Dec. 31, 2020
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	1,000,000,000	1,000,000,000
Common stock, shares issued (in shares)	101,903,979	64,015,441
Common stock, shares outstanding (in shares)	101,903,979	64,015,441

Consolidated Statements of Oper

Consolidated Statements of Operations (Unaudited) - USD ($)	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Operating expenses:
Research and development	$ 2,916,378	$ 1,534,467
General and administrative	1,743,510	1,393,808
Depreciation	24,447	27,020
Loss from operations	4,684,335	2,955,295
Other income:
Interest income	(40,416)	(34,100)
Loss from operations before income tax benefit	(4,643,919)	(2,921,195)
Income tax benefit		362,380
Net loss	$ (4,643,919)	$ (2,558,815)
Per share information:
Net loss per share of common stock, basic and diluted (in dollars per share)	$ (0.06)	$ (0.07)
Weighted average shares outstanding, basic and diluted (in dollars per share)	$ 83,420,184	$ 34,507,496

Consolidated Statements of Chan

Consolidated Statements of Changes in Stockholders' Equity (Unaudited) - USD ($)	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Total
Balance (in shares) at Dec. 31, 2019	33,480,365
Balance at Dec. 31, 2019	$ 33,481	$ 111,824,859	$ (91,724,078)	$ 20,134,262
Issuance of common stock upon exercise of warrants, net of issuance costs (in shares)	1,124,071
Issuance of common stock upon exercise of warrants, net of issuance costs	$ 1,124	133,674		134,798
Stock-based compensation expense		191,380		191,380
Net loss			(2,747,809)	(2,558,815)
Balance (in shares) at Mar. 31, 2020	34,604,436
Balance at Mar. 31, 2020	$ 34,605	112,149,913	(94,471,887)	17,901,625
Balance (in shares) at Dec. 31, 2020	64,015,441
Balance at Dec. 31, 2020	$ 64,016	130,659,550	(105,909,384)	24,814,182
Stock-based compensation expense		181,280		181,280
Net loss			(4,643,919)	(4,643,919)
Sale of common stock, net of issuance costs (in shares)	33,658,538
Sale of common stock, net of issuance costs	$ 33,658	31,060,644		31,094,302
Issuance of common stock upon exercise of warrants (in shares)	4,230,000
Issuance of common stock upon exercise of warrants	$ 4,230	2,197,220		2,201,450
Balance (in shares) at Mar. 31, 2021	101,903,979
Balance at Mar. 31, 2021	$ 101,904	$ 164,098,694	$ (110,553,303)	$ 53,647,295

Consolidated Statements of Cash

Consolidated Statements of Cash Flows (Unaudited) - USD ($)	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Operating activities:
Net loss	$ (4,643,919)	$ (2,558,815)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation	24,447	27,020
Stock-based compensation expense	181,280	191,380
Change in deferred income taxes		(362,380)
Changes in operating assets and liabilities:
Prepaid expenses, deposits and other assets	(417,677)	(346,030)
Accounts payable, accrued expenses and other liabilities	(320,501)	(455,489)
Net cash used in operating activities	(5,176,370)	(3,504,314)
Cash flows provided by financing activities:
Proceeds from the sale of common stock, net of issuance costs	31,094,302
Proceeds received from the exercise of common stock warrants	2,201,450	393,425
Payment of financing costs that were previously classified in accounts payable		(238,232)
Net cash provided by financing activities	33,295,752	155,193
Net increase (decrease) in cash and cash equivalents	28,119,382	(3,349,121)
Cash and cash equivalents at beginning of period	18,515,595	14,177,349
Cash and cash equivalents at end of period	46,634,977	10,828,228
Supplemental disclosure of non-cash financing activities:
Offering costs in accounts payable and accrued expenses		$ 258,627

Note 1 - Organization and Descr

Note 1 - Organization and Description of Business	3 Months Ended
	Mar. 31, 2021
Notes to Financial Statements
Nature of Operations [Text Block]	1. Organization and Description of Business Diffusion Pharmaceuticals Inc., a Delaware corporation, is an innovative biopharmaceutical company developing novel therapies that enhance the body's ability to deliver oxygen to the areas where it is needed most. The Company's lead product candidate, TSC, is being developed to enhance the diffusion of oxygen to tissues with low oxygen levels, also known as hypoxia, a serious complication of many of medicine's most intractable and difficult-to-treat conditions. In addition to TSC, the Company's product candidate DFN- 529, PI3K/Akt/mTOR two 1 529 529

Note 2 - Liquidity

Note 2 - Liquidity	3 Months Ended
	Mar. 31, 2021
Notes to Financial Statements
Liquidity Disclosure [Text Block]	2. Liquidity The Company has not No The Company regularly explores alternative means of financing its operations and seeks funding through various sources, including public and private securities offerings, collaborative arrangements with third not may third may not Operations of the Company are subject to certain risks and uncertainties including various internal and external factors that will affect whether and when the Company's product candidates become approved drugs and how significant their market share will be, some of which are outside of the Company's control. The length of time and cost of developing and commercializing these product candidates and/or failure of them at any stage of the drug approval process will materially affect the Company's financial condition and future operations. The Company expects that its existing cash and cash equivalents as of March 31, 2021 2023.

Note 3 - Basis of Presentation

Note 3 - Basis of Presentation and Summary of Significant Accounting Policies	3 Months Ended
	Mar. 31, 2021
Notes to Financial Statements
Significant Accounting Policies [Text Block]	3. Basis of Presentation and Summary of Significant Accounting Policies The Summary of Significant Accounting Policies included in the Company's Annual Report for the year ended December 31, 2020 not Basis of Presentation The accompanying unaudited interim consolidated financial statements of the Company have been prepared in accordance with GAAP for interim financial information as found in the ASC and ASUs of the FASB, and with the instructions to Form 10 10 X March 31, 2021, three March 31, 2021 2020. three March 31, 2021 not may December 31, 2021. not December 31, 2020 10 March 16, 2021. Use of Estimate The preparation of unaudited interim consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of assets and liabilities at the date the financial statements and reported amounts of expense during the reporting period. The COVID- 19 no March 31, 2021. 19 may 19, 19, may 19, Fair Value of Financial Instruments The carrying amounts of the Company's financial instruments, including cash equivalents and accounts payable, approximate fair value due to the short-term nature of those instruments. Intangible Asset The Company's DFN- 529 529 October 1 no 529 three March 31, 2021 2020. Net Loss Per Common Share Basic net loss per share is computed by dividing net loss attributable to common stockholders by the weighted average number of shares of common stock outstanding during each period. Diluted net loss per share includes the effect, if any, from the potential exercise or conversion of securities, such as convertible debt, convertible preferred stock, common stock warrants, stock options and unvested restricted stock that would result in the issuance of incremental shares of common stock. In computing the basic and diluted net loss per share applicable to common stockholders, the weighted average number of shares remains the same for both calculations due to the fact that when a net loss exists, dilutive shares are not The following potentially dilutive securities outstanding as of March 31, 2021 2020 March 31, 2021 2020 Common stock warrants 6,553,039 21,261,070 Stock options 3,116,819 1,182,629 Unvested restricted stock awards 153,000 98,100 9,822,858 22,541,799 Recently Adopted Accounting Pronouncements In December 2019, No. 2019 12, 740 Simplifying the Accounting for Income Taxes December 15, 2020 No. 2019 12 first 2021 not

Note 4 - Accrued Expenses and O

Note 4 - Accrued Expenses and Other Current Liabilities	3 Months Ended
	Mar. 31, 2021
Notes to Financial Statements
Accounts Payable, Accrued Liabilities, and Other Liabilities Disclosure, Current [Text Block]	4. Accrued Expenses and Other Current Liabilities Accrued expenses and other current liabilities consisted of the following: March 31, 2021 December 31, 2020 Accrued payroll and payroll related expenses $ 510,002 $ 653,899 Accrued professional fees 77,258 31,809 Accrued clinical studies expenses 406,439 1,055,398 Other accrued expenses 55,205 35,364 Total $ 1,048,904 $ 1,776,470

Note 5 - Stockholders' Equity a

Note 5 - Stockholders' Equity and Common Stock Warrants	3 Months Ended
	Mar. 31, 2021
Notes to Financial Statements
Stockholders' Equity Note Disclosure [Text Block]	5. Stockholders' Equity and Common Stock Warrants February 2021 In February 2021, February 2021 33,658,538 $1.025 30 February 2021 $31.1 February 2021 1,682,927 $1.28125 five Common Stock Warrants As of March 31, 2021, Outstanding Range of exercise price per share Expiration dates Common stock warrants issued in 2017 related to Series A convertible preferred stock offering 903,870 $33.30 March 2022 Common stock warrants issued in 2018 related to January 2018 Offering 1,181,421 $12.00 - $15.00 January 2023 Common stock warrants issued related to the May 2019 Offering 1,382,913 $5.00 - $6.11875 May and December 2024 Common stock warrants issued related to the November 2019 Offering 267,140 $0.35 May 2021 and November 2024 Common stock warrants issued related to the December 2019 Offering 313,339 $0.4335 - $0.6981 December 2024 and June 2025 Common stock warrants issued related to the May 2020 Offering 571,429 $1.31 March 2025 Common stock warrants issued related to the May 2020 Investor Warrant Exercise 250,000 $0.5938 November 2025 Common stock warrants issued related to the February 2021 Offering 1,682,927 $1.28 February 2026 6,553,039 During the three March 31, 2021, no 4,230,000 $2.2

Note 6 - Stock-based Compensati

Note 6 - Stock-based Compensation	3 Months Ended
	Mar. 31, 2021
Notes to Financial Statements
Share-based Payment Arrangement [Text Block]	6. Stock-Based Compensation 2015 The 2015 January 1 4.0% December 31, 2,560,618 January 1, 2021, may 2015 March 31, 2021, 1,229,005 2015 The Company recorded stock-based compensation expense in the following expense categories of its unaudited interim consolidated statements of operations for the periods indicated: Three Months Ended March 31, 2021 2020 Research and development $ 33,000 $ 96,530 General and administrative 148,280 94,850 Total stock-based compensation expense $ 181,280 $ 191,380 The following table summarizes the activity related to all stock option grants for the three March 31, 2021: Number of Options Weighted average exercise price per share Weighted average remaining contractual life (in years) Aggregate intrinsic value Balance at January 1, 2021 2,240,204 $ 8.28 Granted 876,615 1.11 Outstanding at March 31, 2021 3,116,819 $ 6.26 9.01 $ 475,258 Exercisable at March 31, 2021 1,363,373 $ 13.10 8.25 $ 331,618 Vested and expected to vest at March 31, 2021 3,116,819 $ 6.26 9.01 $ 475,258 The weighted average grant date fair value of stock option awards granted was $1.06 three March 31, 2021. three March 31, 2021 2020 $0.2 $0.2 No March 31, 2021, $1.4 2.29 three March 31, 2021, 385,267 $1.11 $27,000 three March 31, 2021, not March 31, 2021, no Options granted were valued using the Black-Scholes-Merton derivative investment instrument pricing model and assumptions used to value the options granted during the three March 31, 2021 Expected term (in years) 10 Risk-free interest rate 1.4 % Expected volatility 124.6 % Dividend yield — Restricted Stock Unit Awards During the year ended December 31, 2020, 153,000 18 none March 31, 2021. $5,000 three March 31, 2021. March 31, 2021, $77,000 2.19

Note 7 - Commitments and Contin

Note 7 - Commitments and Contingencies	3 Months Ended
	Mar. 31, 2021
Notes to Financial Statements
Commitments and Contingencies Disclosure [Text Block]	7. Commitments and Contingencies Office Space Lease Commitment The Company has a non-cancelable operating lease for office and laboratory space in Charlottesville, Virginia, which began in April 2017 March 31, 2021, 1.1 10.0%. second 2022 5 not March 31, 2021. Rent expense related to the Company's operating lease was approximately $31,000 $30,000 three March 31, 2021 2020, March 31, 2021: Rental Commitments 2021 (remaining) 89,232 2022 39,735 Total 128,967 Less: imputed interest (8,857 ) Current and noncurrent operating lease liability $ 120,110 Research and Development Arrangements In the course of normal business operations, the Company enters into agreements with universities and CROs to assist in the performance of research and development activities and contract manufacturers to assist with chemistry, manufacturing, and controls related expenses. Expenditures to CROs represent a significant cost in clinical development for the Company. The Company could also enter into additional collaborative research, contract research, manufacturing, and supplier agreements in the future, which may Defined Contribution Retirement Plan The Company has established its 401 may 401 90.00% 4.0% 401 $16,000 $17,000 three March 31, 2021 2020, Legal Proceedings On August 7, 2014, No. BC553996 December 30, 2014, April 1, 2015, April 14, 2015, January 8, 2016, November 19, 2018 not November 2020. August 2020, 19 August 16, 2021. may

Significant Accounting Policies

Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2021
Accounting Policies [Abstract]
Basis of Accounting, Policy [Policy Text Block]	Basis of Presentation The accompanying unaudited interim consolidated financial statements of the Company have been prepared in accordance with GAAP for interim financial information as found in the ASC and ASUs of the FASB, and with the instructions to Form 10 10 X March 31, 2021, three March 31, 2021 2020. three March 31, 2021 not may December 31, 2021. not December 31, 2020 10 March 16, 2021.
Use of Estimates, Policy [Policy Text Block]	Use of Estimate The preparation of unaudited interim consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of assets and liabilities at the date the financial statements and reported amounts of expense during the reporting period. The COVID- 19 no March 31, 2021. 19 may 19, 19, may 19,
Fair Value of Financial Instruments, Policy [Policy Text Block]	Fair Value of Financial Instruments The carrying amounts of the Company's financial instruments, including cash equivalents and accounts payable, approximate fair value due to the short-term nature of those instruments.
Goodwill and Intangible Assets, Policy [Policy Text Block]	Intangible Asset The Company's DFN- 529 529 October 1 no 529 three March 31, 2021 2020.
Earnings Per Share, Policy [Policy Text Block]	Net Loss Per Common Share Basic net loss per share is computed by dividing net loss attributable to common stockholders by the weighted average number of shares of common stock outstanding during each period. Diluted net loss per share includes the effect, if any, from the potential exercise or conversion of securities, such as convertible debt, convertible preferred stock, common stock warrants, stock options and unvested restricted stock that would result in the issuance of incremental shares of common stock. In computing the basic and diluted net loss per share applicable to common stockholders, the weighted average number of shares remains the same for both calculations due to the fact that when a net loss exists, dilutive shares are not The following potentially dilutive securities outstanding as of March 31, 2021 2020 March 31, 2021 2020 Common stock warrants 6,553,039 21,261,070 Stock options 3,116,819 1,182,629 Unvested restricted stock awards 153,000 98,100 9,822,858 22,541,799
New Accounting Pronouncements, Policy [Policy Text Block]	Recently Adopted Accounting Pronouncements In December 2019, No. 2019 12, 740 Simplifying the Accounting for Income Taxes December 15, 2020 No. 2019 12 first 2021 not

Note 3 - Basis of Presentatio_2

Note 3 - Basis of Presentation and Summary of Significant Accounting Policies (Tables)	3 Months Ended
	Mar. 31, 2021
Notes Tables
Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table Text Block]	March 31, 2021 2020 Common stock warrants 6,553,039 21,261,070 Stock options 3,116,819 1,182,629 Unvested restricted stock awards 153,000 98,100 9,822,858 22,541,799

Note 4 - Accrued Expenses and_2

Note 4 - Accrued Expenses and Other Current Liabilities (Tables)	3 Months Ended
	Mar. 31, 2021
Notes Tables
Other Current Liabilities [Table Text Block]	March 31, 2021 December 31, 2020 Accrued payroll and payroll related expenses $ 510,002 $ 653,899 Accrued professional fees 77,258 31,809 Accrued clinical studies expenses 406,439 1,055,398 Other accrued expenses 55,205 35,364 Total $ 1,048,904 $ 1,776,470

Note 5 - Stockholders' Equity_2

Note 5 - Stockholders' Equity and Common Stock Warrants (Tables)	3 Months Ended
	Mar. 31, 2021
Notes Tables
Schedule of Stockholders' Equity Note, Warrants or Rights [Table Text Block]	Outstanding Range of exercise price per share Expiration dates Common stock warrants issued in 2017 related to Series A convertible preferred stock offering 903,870 $33.30 March 2022 Common stock warrants issued in 2018 related to January 2018 Offering 1,181,421 $12.00 - $15.00 January 2023 Common stock warrants issued related to the May 2019 Offering 1,382,913 $5.00 - $6.11875 May and December 2024 Common stock warrants issued related to the November 2019 Offering 267,140 $0.35 May 2021 and November 2024 Common stock warrants issued related to the December 2019 Offering 313,339 $0.4335 - $0.6981 December 2024 and June 2025 Common stock warrants issued related to the May 2020 Offering 571,429 $1.31 March 2025 Common stock warrants issued related to the May 2020 Investor Warrant Exercise 250,000 $0.5938 November 2025 Common stock warrants issued related to the February 2021 Offering 1,682,927 $1.28 February 2026 6,553,039

Note 6 - Stock-based Compensa_2

Note 6 - Stock-based Compensation (Tables)	3 Months Ended
	Mar. 31, 2021
Notes Tables
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Table Text Block]	Three Months Ended March 31, 2021 2020 Research and development $ 33,000 $ 96,530 General and administrative 148,280 94,850 Total stock-based compensation expense $ 181,280 $ 191,380
Share-based Payment Arrangement, Option, Activity [Table Text Block]	Number of Options Weighted average exercise price per share Weighted average remaining contractual life (in years) Aggregate intrinsic value Balance at January 1, 2021 2,240,204 $ 8.28 Granted 876,615 1.11 Outstanding at March 31, 2021 3,116,819 $ 6.26 9.01 $ 475,258 Exercisable at March 31, 2021 1,363,373 $ 13.10 8.25 $ 331,618 Vested and expected to vest at March 31, 2021 3,116,819 $ 6.26 9.01 $ 475,258
Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Table Text Block]	Expected term (in years) 10 Risk-free interest rate 1.4 % Expected volatility 124.6 % Dividend yield —

Note 7 - Commitments and Cont_2

Note 7 - Commitments and Contingencies (Tables)	3 Months Ended
	Mar. 31, 2021
Notes Tables
Lessee, Operating Lease, Liability, Maturity [Table Text Block]	Rental Commitments 2021 (remaining) 89,232 2022 39,735 Total 128,967 Less: imputed interest (8,857 ) Current and noncurrent operating lease liability $ 120,110

Note 3 - Basis of Presentatio_3

Note 3 - Basis of Presentation and Summary of Significant Accounting Policies (Details Textual) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
In-Process Research and Development Asset [Member]
Impairment of Intangible Assets, Indefinite-lived (Excluding Goodwill)	$ 0	$ 0

Note 3 - Basis of Presentatio_4

Note 3 - Basis of Presentation and Summary of Significant Accounting Policies - Outstanding Dilutive Securities (Details) - shares	3 Months Ended
	Mar. 31, 2021	Mar. 30, 2020
Anti-dilutive securities (in shares)	9,822,858	22,541,799
Warrant [Member]
Anti-dilutive securities (in shares)	6,553,039	21,261,070
Share-based Payment Arrangement, Option [Member]
Anti-dilutive securities (in shares)	3,116,819	1,182,629
Restricted Stock [Member]
Anti-dilutive securities (in shares)	153,000	98,100

Note 4 - Accrued Expenses and_3

Note 4 - Accrued Expenses and Other Current Liabilities - Summary of Accrued Expenses (Details) - USD ($)	Mar. 31, 2021	Dec. 31, 2020
Accrued payroll and payroll related expenses	$ 510,002	$ 653,899
Accrued professional fees	77,258	31,809
Accrued clinical studies expenses	406,439	1,055,398
Other accrued expenses	55,205	35,364
Total	$ 1,048,904	$ 1,776,470

Note 5 - Stockholders' Equity_3

Note 5 - Stockholders' Equity and Common Stock Warrants (Details Textual) - USD ($)	1 Months Ended	3 Months Ended
	Feb. 28, 2021	Mar. 31, 2021	Mar. 31, 2020
Proceeds from Issuance of Common Stock		$ 31,094,302
Class of Warrant or Rights, Expired (in shares)		0
Class of Warrant or Right, Exercised During Period (in shares)		4,230,000
Proceeds from Warrant Exercises		$ 2,201,450	$ 393,425
Underwriter Warrants in Connection with the February 2021 Common Stock Offering [Member]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares)	1,682,927
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)	$ 1.28125	$ 1.28
Warrants and Rights Outstanding, Term (Year)	5 years
Public Offering, Inclusive of Underwriter Shares [Member]
Stock Issued During Period, Shares, New Issues (in shares)	33,658,538
Shares Issued, Price Per Share (in dollars per share)	$ 1.025
Underwriter Option to Purchase Additional Shares, Term (Day)	30 days
Proceeds from Issuance of Common Stock	$ 31,100,000

Note 5 - Stockholders' Equity_4

Note 5 - Stockholders' Equity and Common Stock Warrants - Warrants Outstanding to Acquire Shares of Its Common Stock (Details) - $ / shares	Mar. 31, 2021	Feb. 28, 2021
Common stock warrants, outstanding (in shares)	6,553,039
Warrants Attached to Series A Convertible Preferred Stock [Member]
Common stock warrants, outstanding (in shares)	903,870
Range of exercise price (in dollars per share)	$ 33.30
Warrants Issued in Connection with the January 2018 Offering [Member]
Common stock warrants, outstanding (in shares)	1,181,421
Warrants Issued in Connection with the January 2018 Offering [Member] | Minimum [Member]
Range of exercise price (in dollars per share)	$ 12
Warrants Issued in Connection with the January 2018 Offering [Member] | Maximum [Member]
Range of exercise price (in dollars per share)	$ 15
Warrants Issued in Connection with May 2019 Public Offering [Member]
Common stock warrants, outstanding (in shares)	1,382,913
Warrants Issued in Connection with May 2019 Public Offering [Member] | Minimum [Member]
Range of exercise price (in dollars per share)	$ 5
Warrants Issued in Connection with May 2019 Public Offering [Member] | Maximum [Member]
Range of exercise price (in dollars per share)	$ 6.11875
Warrants Issued in Connection with the November 2019 Offering [Member]
Common stock warrants, outstanding (in shares)	267,140
Range of exercise price (in dollars per share)	$ 0.35
Warrants Issued in Connection with the December 2019 Offering [Member]
Common stock warrants, outstanding (in shares)	313,339
Warrants Issued in Connection with the December 2019 Offering [Member] | Minimum [Member]
Range of exercise price (in dollars per share)	$ 0.4335
Warrants Issued in Connection with the December 2019 Offering [Member] | Maximum [Member]
Range of exercise price (in dollars per share)	$ 0.6981
The May 2020 Offering Warrants [Member]
Common stock warrants, outstanding (in shares)	571,429
Range of exercise price (in dollars per share)	$ 1.31
The May 2020 Investor Warrant Exercise [Member]
Common stock warrants, outstanding (in shares)	250,000
Range of exercise price (in dollars per share)	$ 0.5938
Underwriter Warrants in Connection with the February 2021 Common Stock Offering [Member]
Common stock warrants, outstanding (in shares)	1,682,927
Range of exercise price (in dollars per share)	$ 1.28	$ 1.28125

Note 6 - Stock-based Compensa_3

Note 6 - Stock-based Compensation (Details Textual) - USD ($)	Jan. 01, 2021	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value (in dollars per share)		$ 1.06
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested in Period, Fair Value		$ 200,000	$ 200,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period (in shares)		0	0
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross (in shares)		876,615
Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price (in dollars per share)		$ 1.11
Share-based Payment Arrangement, Expense		$ 181,280	$ 191,380
Share-based Payment Arrangement, Option [Member]
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount, Total		$ 1,400,000
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition (Year)		2 years 105 days
Share-based Payment Arrangement, Expense		$ 27,000
Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross (in shares)		385,267
Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price (in dollars per share)		$ 1.11
Share-based Payment Arrangement, Expense		$ 0
Restricted Stock Units (RSUs) [Member] | Director [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period (in shares)				153,000
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period (Month)				1 year 180 days
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period (in shares)		0
Restricted Stock [Member]
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount, Total		$ 77,000
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition (Year)		2 years 69 days
Share-based Payment Arrangement, Expense		$ 5,000
Equity Incentive Plan 2015 [Member]
Percentage of Total Shares Eligible for Plan Reserve, On an Annual Basis		4.00%
Share-based Compensation Arrangement by Share-based Payment Award, Number of Additional Shares Authorized (in shares)	2,560,618
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant (in shares)		1,229,005

Note 6 - Stock-based Compensa_4

Note 6 - Stock-based Compensation - Stock-based Compensation Expense (Details) - USD ($)	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Stock-based compensation expense	$ 181,280	$ 191,380
Research and Development Expense [Member]
Stock-based compensation expense	33,000	96,530
General and Administrative Expense [Member]
Stock-based compensation expense	$ 148,280	$ 94,850

Note 6 - Stock-based Compensa_5

Note 6 - Stock-based Compensation - Stock Option Activity (Details)	3 Months Ended
	Mar. 31, 2021USD ($)$ / sharesshares
Options outstanding, number (in shares) | shares	2,240,204
Options outstanding, weighted-average exercise price (in dollars per share) | $ / shares	$ 8.28
Granted (in shares) | shares	876,615
Granted, weighted-average exercise price (in dollars per share) | $ / shares	$ 1.11
Options outstanding, number (in shares) | shares	3,116,819
Options outstanding, weighted-average exercise price (in dollars per share) | $ / shares	$ 6.26
Options outstanding, weighted-average remaining contractual life (Year)	9 years 3 days
Options outstanding, aggregate intrinsic value | $	$ 475,258
Exercisable (in shares) | shares	1,363,373
Exercisable, weighted-average exercise price (in dollars per share) | $ / shares	$ 13.10
Exercisable, weighted-average remaining contractual life (Year)	8 years 91 days
Exercisable, aggregate intrinsic value | $	$ 331,618
Vested and expected to vest (in shares) | shares	3,116,819
Vested and expected to vest, weighted-average exercise price (in dollars per share) | $ / shares	$ 6.26
Vested and expected to vest, weighted-average remaining contractual life (Year)	9 years 3 days
Vested and expected to vest, aggregate intrinsic value | $	$ 475,258

Note 6 - Stock-based Compensa_6

Note 6 - Stock-based Compensation - Fair Value Assumptions (Details) - Minimum [Member]	3 Months Ended
	Mar. 31, 2021
Expected term (Year)	10 years
Risk-free interest rate	1.40%
Expected volatility	124.60%
Dividend yield

Note 7 - Commitments and Cont_3

Note 7 - Commitments and Contingencies (Details Textual) - USD ($)	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Lessee, Operating Lease, Remaining Lease Term (Year)	1 year 36 days
Lessee, Operating Lease, Discount Rate	10.00%
Lessee, Operating Lease, Renewal Term (Year)	5 years
Operating Lease, Expense	$ 31,000	$ 30,000
Defined Contribution Plan, Maximum Annual Contributions Per Employee, Percent	90.00%
Defined Contribution Plan, Employer Matching Contribution, Percent of Employees' Gross Pay	4.00%
Defined Contribution Plan, Employer Discretionary Contribution Amount	$ 16,000	$ 17,000

Note 7 - Commitments and Cont_4

Note 7 - Commitments and Contingencies - Future Minimum Rental Payments (Details)	Mar. 31, 2021USD ($)
2021 (remaining)	$ 89,232
2022	39,735
Total	128,967
Less: imputed interest	(8,857)
Current and noncurrent operating lease liability	$ 120,110