Note 4 - Stockholders' Equity, Stock Options and Warrants (Details Textual) - USD ($)				2 Months Ended	9 Months Ended		12 Months Ended
	Dec. 01, 2022	May 16, 2022	Oct. 24, 2019	Feb. 28, 2021	Sep. 30, 2022	Sep. 30, 2021	Dec. 31, 2022	Dec. 31, 2021	May 15, 2022	Aug. 17, 2021	Jun. 30, 2021	Dec. 31, 2020
Common Stock, Shares Authorized (in shares)							200,000,000	200,000,000		200,000,000
Common Stock, Par or Stated Value Per Share (in dollars per share)							$ 0.01	$ 0.01		$ 0.01
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)							$ 1.13	$ 1.66				$ 1.99
Sale of Stock, Agent Placement Fee, Percent of Gross Proceeds				7.50%
Sale of Stock, Management Fee, Percent of Gross Proceeds				1.00%
Proceeds from Warrant Exercises							$ 0	$ 4,513,871
Stock Issued During Period, Value, New Issues							$ 6,507,050
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Vested and Expected to Vest, Exercisable, Number (in shares)							953,635	949,615
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Vested and Expected to Vest, Outstanding, Weighted Average Exercise Price (in dollars per share)							$ 4.69	$ 5.27
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Vested and Expected to Vest, Outstanding, Weighted Average Remaining Contractual Term (Year)							6 years 6 months 14 days	8 years 1 month 20 days
Class of Warrant or Right Number of Warrants Vested and Exercisable (in shares)							36,328,731	31,699,885
Share-Based Payment Arrangement, Expense							$ 108,596	$ 146,714
Share-Based Payment Arrangement, Nonvested Award, Option, Cost Not yet Recognized, Amount							$ 16,045
Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition (Month)							23 months
Restricted Stock Units (RSUs) [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Grants in Period (in shares)							450,000
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Vested in Period (in shares)							333,333	33,333
Share-Based Compensation Arrangement by Share-Based Payment Award, Non-Option Equity Instruments, Outstanding, Number, Ending Balance (in shares)							83,334
Stock Incentive Plan 2012 [Member]
Common Stock, Capital Shares Reserved for Future Issuance (in shares)	5,750,000									3,250,000	1,500,000
Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Additional Shares Authorized (in shares)	3,250,000
Minimum [Member]
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)							$ 0.70
Maximum [Member]
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)							$ 13.13
Maximum [Member] | Share-Based Payment Arrangement, Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period (Year)								3 years
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period (Year)								10 years
Maximum [Member] | Equity Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period (Year)						3 years
Warrants Issued with First May 2022 Offering [Member]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares)		3,837,280
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)		$ 0.70
Warrants and Rights Outstanding, Term (Year)		5 years 6 months
Existing Warrants [Member]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares)		16,325,433
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)		$ 0.70
Warrants and Rights Outstanding, Term (Year)		5 years 6 months
Existing Warrants [Member] | Minimum [Member]
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)									$ 1.00
Existing Warrants [Member] | Maximum [Member]
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)									$ 2.00
Placement Agent Warrants [Member]
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)		$ 0.75
Sale of Stock, Placement Agent, Warrants Assigned, Number of Securities Called by Warrants, Percent of Shares Sold		7.50%		7.50%
Class of Warrant or Right, Exercise Price of Warrants or Rights, Percent of Stock Price		125.00%		125.00%
Investor Warrants [Member]
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)								$ 0.86
Stock Issued During Period, Shares, Warrant Exercises (in shares)								5,269,059
Proceeds from Warrant Exercises								$ 4,513,871
Warrant [Member]
Share-Based Payment Arrangement, Expense							$ 108,596	146,714
May 2022 First Offering [Member]
Stock Issued During Period, Shares, New Issues (in shares)		3,837,280
Shares Issued, Price Per Share (in dollars per share)		$ 0.60
May 2022 Second Offering [Member]
Stock Issued During Period, Shares, New Issues (in shares)		8,162,720
Shares Issued, Price Per Share (in dollars per share)		$ 0.60
May 2022 Offerings [Member]
Sale of Stock, Agent Placement Fee, Percent of Gross Proceeds		7.50%
Sale of Stock, Management Fee, Percent of Gross Proceeds		1.00%
Maximum Expenses Reimbursable to Placement Agent		$ 65,000
Registered Direct Offerings [Member]
Number of Warrants Issued to Each Investor, Per Two Shares of Stock Purchased (in shares)				1
Stock Issued During Period, Value, New Issues								15,012,492
Registered Direct Offerings [Member] | Placement Agent Warrants [Member]
Warrants and Rights Outstanding, Term (Year)				5 years
Registered Direct Offerings [Member] | Investor Warrants [Member]
Warrants and Rights Outstanding, Term (Year)				5 years 6 months
Private Placement [Member]
Number of Warrants Issued to Each Investor, Per Two Shares of Stock Purchased (in shares)				1
Stock Issued During Period, Value, New Issues								16,064,739
Private Placement [Member] | Placement Agent Warrants [Member]
Warrants and Rights Outstanding, Term (Year)				5 years 6 months
June 2021 Offering [Member] | Placement Agent Warrants [Member]
Warrants and Rights Outstanding, Term (Year)				3 years
Equity Line Purchase Agreement [Member]
Stock Issued During Period, Shares, New Issues (in shares)			104,651		315,000
Issuance or Sale of Equity, Can Be Raised			$ 15,000,000
Stock Issued During Period, Value, New Issues			$ 450,000		$ 236,009
Sale of Stock, Remaining Available Balance								$ 9,113,829