Note 10 - Stockholders' Equity (Details Textual)							1 Months Ended	3 Months Ended		9 Months Ended
	Sep. 29, 2020 USD ($) $ / shares shares	Sep. 25, 2020	Sep. 24, 2020 USD ($) $ / shares shares	Jan. 24, 2020 USD ($) shares	Jan. 21, 2020	Apr. 30, 2019	Jul. 31, 2020 shares	Sep. 30, 2020 USD ($) $ / shares shares	Mar. 31, 2020 shares	Sep. 30, 2020 USD ($) $ / shares shares	Sep. 30, 2019 shares	Jun. 26, 2020 $ / shares shares	Dec. 31, 2019 $ / shares shares
Preferred Stock, Shares Authorized (in shares)								10,000,000		10,000,000			10,000,000
Preferred Stock, Par or Stated Value Per Share (in dollars per share) | $ / shares								$ 0.01		$ 0.01			$ 0.01
Preferred Stock, Shares Outstanding, Ending Balance (in shares)								100		100			2,486
Proceeds from Issuance or Sale of Equity, Gross | $			$ 12,800,000
Proceeds from Issuance or Sale of Equity, Total | $			$ 11,200,000
Number of Common Stock Securities Called by Each Unit (in shares)	1
Deferred Compensation Liability Conversion to Equity, Amount | $	$ 1,500,000									$ 1,500,000
Deferred Compensation Liability Conversion to Equity, Conversion Price (in dollars per share) | $ / shares	$ 5
Stock Issued During Period, Shares, Cancellation of Accrued Compensation (in shares)	300,001									300,001
Stock Issued During Period, Shares, Conversion of Convertible Securities (in shares)	177,625
Stock Issued During Period, Shares, Issued for Services (in shares)										3,162
Class of Warrant or Right, Outstanding (in shares)								3,850,337		3,850,337
Stock Issued During Period, Shares, Warrants Exercised (in shares)										36,902
Share-based Payment Arrangement, Nonvested Award, Option, Cost Not yet Recognized, Amount | $								$ 0		$ 0
Stock Issued During Period, Value Expensed During the Period, Issued for Services | $								6,000		24,000
Share-based Payment Arrangement, Option [Member]
Share-based Payment Arrangement, Expense | $								$ 0		$ 0
Stock Incentive Plan 2020 [Member]
Common Stock, Capital Shares Reserved for Future Issuance (in shares)								250,000		250,000
Conversion from Convertible Debentures to Conversion Units [Member]
Debt Conversion, Converted Instrument, Principal and Interest, Amount | $	$ 1,214,667
Representative [Member]
Over-Allotment Option, Term (Day)			45 days
Number of Units Granted for Over-Allotment (in shares)			384,000
Capital Units [Member]
Stock Issued During Period, Shares, New Issues (in shares)			2,560,000
Shares Issued, Price Per Share (in dollars per share) | $ / shares			$ 5
Conversion Warrants [Member]
Class Of Warrant Or Right, Issued During Period (in shares)			2,560,000
Conversion Warrants [Member] | Conversion from Convertible Debentures to Conversion Units [Member]
Debt Conversion, Converted Instrument, Warrants or Options Issued (in shares)	303,667
Unit Warrant [Member]
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right (in shares)			1
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) | $ / shares			$ 5
Warrants and Rights Outstanding, Term (Year)			5 years
Pre-Funded Warrants [Member]
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right (in shares)	1		1
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) | $ / shares	$ 0.01		$ 0.01					$ 0.01		$ 0.01
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares)	250,000
Class of Warrant or Right, Outstanding (in shares)								376,042		376,042
Pre-Funded Warrants [Member] | Conversion from Convertible Debentures to Conversion Units [Member]
Debt Conversion, Converted Instrument, Warrants or Options Issued (in shares)	126,042									126,042
Representative Warrants [Member]
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) | $ / shares			$ 5.50					$ 5.5		$ 5.5
Warrants and Rights Outstanding, Term (Year)			3 years
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares)	128,000		128,000
Class of Warrant or Right, Period for Warrants or Rights Exercisable (Day)			180 days
Class of Warrant or Right, Outstanding (in shares)								128,000		128,000
Management Warrant [Member]
Number of Warrants Called by Each Unit (in shares)	1
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares)	300,001
Series G Warrants [Member]
Class of Warrant or Right, Outstanding (in shares)								0		0
Series H Warrants [Member]
Class of Warrant or Right, Outstanding (in shares)								0		0
Stock Issued During Period, Shares, Warrants Exercised (in shares)							7,147
Series I Warrants [Member]
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) | $ / shares								$ 5		$ 5
Class of Warrant or Right, Outstanding (in shares)								62,626		62,626
Stock Issued During Period, Shares, Warrants Exercised (in shares)							29,755
June 2020 Warrants [Member]
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) | $ / shares	$ 5							$ 5		$ 5		$ 10
Warrants and Rights Outstanding, Term (Year)												5 years
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares)												120,000
Class of Warrant or Right, Outstanding (in shares)								120,000		120,000
Unit Warrants [Member]
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right (in shares)	1
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) | $ / shares	$ 5
Warrants and Rights Outstanding, Term (Year)	5 years
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares)	2,560,000
Unit Warrants [Member] | Conversion from Convertible Debentures to Conversion Units [Member]
Debt Conversion, Converted Instrument, Warrants or Options Issued (in shares)										303,668
Reverse Stock Split [Member]
Stockholders' Equity Note, Stock Split, Conversion Ratio		20			2,000	500
Conversion of Series H Preferred Stock Into Common Stock [Member]
Conversion of Stock, Shares Converted (in shares)									1,686
Conversion of Stock, Shares Issued (in shares)									469,696
Conversion of Series I Preferred Stock Into Common Stock [Member]
Conversion of Stock, Shares Converted (in shares)									700
Conversion of Stock, Shares Issued (in shares)									204,371
Conversion of Series J Preferred Stock into Common Stock [Member]
Conversion of Stock, Shares Converted (in shares)							300
Conversion of Stock, Shares Issued (in shares)							42,723
Conversion of Series H, Series I, and Series J Preferred Stock into Common Stock [Member]
Conversion of Stock, Shares Issued (in shares)										716,790	2,378
Series B Convertible Preferred Stock [Member]
Preferred Stock, Par or Stated Value Per Share (in dollars per share) | $ / shares								$ 1,000		$ 1,000			$ 1,000
Preferred Stock, Shares Outstanding, Ending Balance (in shares)								100		100			100
Series H Convertible Preferred Stock [Member]
Preferred Stock, Shares Outstanding, Ending Balance (in shares)								0		0			1,686
Series I Convertible Preferred Stock [Member]
Preferred Stock, Shares Outstanding, Ending Balance (in shares)								0		0			700
Series J Convertible Preferred Stock [Member]
Preferred Stock, Shares Outstanding, Ending Balance (in shares)								0		0
Stock Issued During Period, Shares, New Issues (in shares)				300
Proceeds from Issuance of Preferred Stock and Preference Stock | $				$ 300,000
Capital Units Tranche One [Member] | Capital Units [Member]
Stock Issued During Period, Shares, New Issues (in shares)			2,310,000
Number of Common Stock Securities Called by Each Unit (in shares)			1
Capital Units Tranche One [Member] | Unit Warrant [Member] | Capital Units [Member]
Number of Warrants Called by Each Unit (in shares)			1
Capital Units Tranche Two [Member] | Capital Units [Member]
Stock Issued During Period, Shares, New Issues (in shares)			250,000
Capital Units Tranche Two [Member] | Unit Warrant [Member] | Capital Units [Member]
Number of Warrants Called by Each Unit (in shares)			1
Capital Units Tranche Two [Member] | Pre-Funded Warrants [Member] | Capital Units [Member]
Number of Warrants Called by Each Unit (in shares)			1
Units Including Pre-Funded Warrants [Member] | Capital Units [Member]
Shares Issued, Price Per Share (in dollars per share) | $ / shares			$ 4.99