Note 9 - Stockholders' Equity, Stock Options and Warrants (Details Textual)						9 Months Ended		12 Months Ended
	Apr. 19, 2023 shares	Mar. 16, 2023 $ / shares shares	Dec. 01, 2022 shares	May 16, 2022 USD ($) $ / shares shares	Oct. 24, 2019 USD ($) shares	Sep. 30, 2022 USD ($) shares	Sep. 30, 2021	Dec. 31, 2023 USD ($) $ / shares shares	Dec. 31, 2022 USD ($) $ / shares shares	Dec. 31, 2021 $ / shares shares
Preferred Stock, Shares Authorized (in shares)								20,000,000	20,000,000
Common Stock, Shares Authorized (in shares)	200,000,000							200,000,000	200,000,000
Class of Warrant or Right, Exercise Price of Warrants or Rights | $ / shares								$ 21.52	$ 22.6	$ 33.2
Stock Issued During Period, Value, New Issues | $									$ 6,507,050
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding, Number (in shares)								47,664
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Vested and Expected to Vest, Exercisable, Number								46,814	47,682
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Vested and Expected to Vest, Outstanding, Weighted Average Exercise Price | $ / shares								$ 83.61	$ 93.8
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Vested and Expected to Vest, Outstanding, Weighted Average Remaining Contractual Term								5 years 6 months 21 days	6 years 6 months 14 days
Class of Warrant or Right Number of Warrants Vested and Exercisable								1,806,589	1,816,437
Share-Based Payment Arrangement, Expense | $								$ 2,038	$ 108,596
Share-Based Payment Arrangement, Nonvested Award, Option, Cost Not yet Recognized, Amount | $								$ 1,644
Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition								16 months
Share-Based Payment Arrangement, Option [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding, Number (in shares)									49,053	53,144
Restricted Stock Units (RSUs) [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Grants in Period										22,500
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Vested in Period									16,667
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding, Number (in shares)									4,167
Share-Based Compensation Arrangement by Share-Based Payment Award, Non-Option Equity Instruments, Outstanding, Number								0
Stock Incentive Plan 2012 [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Additional Shares Authorized			162,500
Common Stock, Capital Shares Reserved for Future Issuance			287,500
Warrants Issued with First May 2022 Offering [Member]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights				191,864
Class of Warrant or Right, Exercise Price of Warrants or Rights | $ / shares				$ 14
Warrants and Rights Outstanding, Term				5 years 6 months
Existing Warrants [Member]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights				816,272
Class of Warrant or Right, Exercise Price of Warrants or Rights | $ / shares				$ 14
Warrants and Rights Outstanding, Term				5 years 6 months
Placement Agent Warrants [Member]
Class of Warrant or Right, Exercise Price of Warrants or Rights | $ / shares				$ 15
Sale of Stock, Placement Agent, Warrants Assigned, Number of Securities Called by Warrants, Percent of Shares Sold				7.50%
Class of Warrant or Right, Exercise Price of Warrants or Rights, Percent of Stock Price				125.00%
May 2022 First Offering [Member]
Stock Issued During Period, Shares, New Issues (in shares)				191,864
Shares Issued, Price Per Share | $ / shares				$ 12
May 2022 Second Offering [Member]
Stock Issued During Period, Shares, New Issues (in shares)				408,136
Shares Issued, Price Per Share | $ / shares				$ 12
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
Equity Line Purchase Agreement [Member]
Stock Issued During Period, Shares, New Issues (in shares)					5,233	15,750
Issuance or Sale of Equity, Can Be Raised | $					$ 15,000,000
Stock Issued During Period, Value, New Issues | $					$ 450,000	$ 236,009
Minimum [Member]
Class of Warrant or Right, Exercise Price of Warrants or Rights | $ / shares								$ 14
Minimum [Member] | Existing Warrants [Member]
Class of Warrant or Right, Exercise Price of Warrants or Rights | $ / shares				$ 20
Maximum [Member]
Class of Warrant or Right, Exercise Price of Warrants or Rights | $ / shares								200
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
Maximum [Member] | Existing Warrants [Member]
Class of Warrant or Right, Exercise Price of Warrants or Rights | $ / shares				$ 40
Reverse Stock Split [Member]
Stockholders' Equity Note, Stock Split, Conversion Ratio	20
Reverse Stock Split [Member] | Minimum [Member]
Stockholders' Equity Note, Stock Split, Conversion Ratio	2
Reverse Stock Split [Member] | Maximum [Member]
Stockholders' Equity Note, Stock Split, Conversion Ratio	25
Series F Preferred Stock [Member]
Preferred Stock, Shares Authorized (in shares)		80,000
Preferred Stock, Par or Stated Value Per Share (in dollars per share) | $ / shares		$ 0.01						$ 0.01
Preferred Stock Dividends, Shares Per Share (in shares)		1
Stock Issued During Period, Shares, New Issues (in shares)		79,404
Preferred Stock, Voting Rights Per Share (in shares)		1,000,000
Series B Convertible Preferred Stock [Member]
Preferred Stock, Shares Authorized (in shares)								2,300,000	2,300,000
Preferred Stock, Par or Stated Value Per Share (in dollars per share) | $ / shares								$ 0.01	$ 0.01
Preferred Stock, Shares Outstanding (in shares)								79,246	79,246
Preferred Stock, Conversion Rate								16