Note 3 - Related Party Transactions (Details Textual) | Mar. 22, 2019USD ($) | Feb. 08, 2019USD ($) | Dec. 21, 2018USD ($) | Jul. 19, 2018USD ($)$ / sharesshares | Jul. 02, 2018USD ($)$ / sharesshares | Jun. 29, 2018USD ($)$ / sharesshares | May 02, 2018USD ($)$ / sharesshares | Mar. 08, 2018USD ($) | Jan. 17, 2018USD ($) | Mar. 31, 2019USD ($)$ / shares | Jan. 31, 2019USD ($)$ / shares | Oct. 31, 2017USD ($)$ / sharesshares | Sep. 30, 2017USD ($)$ / sharesshares | Aug. 31, 2017USD ($)$ / sharesshares | Jul. 31, 2016$ / shares | Jul. 31, 2015USD ($)$ / sharesshares | Mar. 31, 2015USD ($) | Mar. 31, 2019USD ($)$ / shares | Mar. 31, 2018USD ($) | Sep. 30, 2018USD ($) | Dec. 31, 2018USD ($)$ / shares | Dec. 31, 2017USD ($) | Dec. 31, 2015USD ($) | May 01, 2019 | Dec. 11, 2018USD ($)shares | Mar. 09, 2018$ / sharesshares | Jan. 18, 2018$ / sharesshares | Dec. 14, 2017USD ($) |
Proceeds from Related Party Debt | | | | | | | | | | | | | | | | | | $ 100,000 | $ 1,000,000 | | | | | | | | | |
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) | $ / shares | | | | | | | | | | $ 1.93 | | | | | | | | $ 1.93 | | | $ 1.86 | | | | | | | |
Debt Instrument, Unamortized Discount, Total | | | | | | | | | | $ 666,638 | | | | | | | | $ 666,638 | | | | | | | | | | |
Amortization of Debt Discount (Premium) | | | | | | | | | | | | | | | | | | 197,335 | 23,642 | | | | | | | | | |
Debt Instrument, Face Amount | | | | | | | | | | 2,525,000 | | | | | | | | 2,525,000 | | | | | | | | | | |
General and Administrative Expense, Total | | | | | | | | | | | | | | | | | | 886,712 | 1,409,696 | | | | | | | | | |
Accounts Payable, Related Parties, Current | | | | | | | | | | 96,826 | | | | | | | | 96,826 | | | $ 127,480 | | | | | | | |
First Note [Member] | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Debt Instrument, Unamortized Discount, Total | | | | | | | | | | | | | | | | | | | | | | | | | $ 11,000 | | | |
Debt Instrument, Face Amount | | | | | | | | | | | | | | | | | | | | | | | | | $ 136,000 | | | |
Third Note [Member] | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Proceeds from Related Party Debt | | | | | | | | | | 50,000 | | | | | | | | | | | | | | | | | | |
Amortization of Debt Discount (Premium) | | | | | | | | | | 3,608 | | | | | | | | | | | | | | | | | | |
Unsecured Promissory Note [Member] | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Debt Instrument, Interest Rate, Stated Percentage | | | | | | | | | | | | | | | | | | | | | | | | | | | | 10.00% |
Debt Instrument, Unamortized Discount, Total | | | | | | | | | | | | | | | | | | | | | | $ 18,652 | | | | | | |
Amortization of Debt Discount (Premium) | | | | | | | | | | | | | | | | | | 2,300 | 2,300 | | | | | | | | | |
Debt Instrument, Face Amount | | | | | | | | | | | | | | | | | | | | | | | | | | | | $ 200,000 |
Warrants Issued with Convertible Promissory Note [Member] | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) | $ / shares | | | | | $ 3 | | | | | | | | | | | | | | | | | | | | | | | |
First Warrant [Member] | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) | $ / shares | | | | | | | | | | | | | | | | | | | | | | | | | | | $ 3 | |
Warrants and Rights Outstanding, Term (Year) | | | | | | | | | | | | | | | | | | | | | | | | | | | 5 years | |
First Warrant [Member] | Maximum [Member] | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares) | shares | | | | | | | | | | | | | | | | | | | | | | | | | 100,000 | | | |
Director [Member] | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares) | shares | | | | | | | | | | | | | 50,000 | | | | | | | | | | | | | | | |
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) | $ / shares | | | | | | | | | | | | | $ 3 | | | | | | | | | | | | | | | |
Warrants and Rights Outstanding, Term (Year) | | | | | | | | | | | | | 5 years | | | | | | | | | | | | | | | |
Director [Member] | Unsecured Promissory Note [Member] | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Proceeds from Related Party Debt | | | | | | $ 1,000,000 | | | | | | | | | | | | | | | | | | | | | | |
Director [Member] | Unsecured Promissory Note [Member] | Third Note [Member] | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Proceeds from Related Party Debt | | | | | | | | $ 200,000 | | | | | | | | | | | | | | | | | | | | |
Debt Instrument, Interest Rate, Stated Percentage | | | | | | | | 10.00% | | | | | | | | | | | | | | | | | | | | |
Debt Instrument, Unamortized Discount, Total | | | | | | | | $ 14,281 | | | | | | | | | | | | | | | | | | | | |
Lender Fees | | | | | | | | | | | | | | | | | | | | $ 6,000 | | | | | | | | |
Director [Member] | Unsecured Promissory Note [Member] | Fifth Note [Member] | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Proceeds from Related Party Debt | | | | | | | $ 300,001 | | | | | | | | | | | | | | | | | | | | | |
Debt Instrument, Interest Rate, Stated Percentage | | | | | | | 10.00% | | | | | | | | | | | | | | | | | | | | | |
Debt Instrument, Unamortized Discount, Total | | | | | | | $ 21,452 | | | | | | | | | | | | | | | | | | | | | |
Lender Fees | | | | | | | $ 9,000 | | | | | | | | | | | | | | | | | | | | | |
Director [Member] | Unsecured Promissory Note [Member] | Fifth Note [Member] | Maximum [Member] | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Debt Instrument, Convertible, Conversion Price (in dollars per share) | $ / shares | | | | | | | $ 3 | | | | | | | | | | | | | | | | | | | | | |
Director [Member] | Unsecured Promissory Note [Member] | Other Expense [Member] | Third Note [Member] | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Amortization of Debt Discount (Premium) | | | | | | | | | | | | | | | | | | 2,500 | | | | | | | | | | |
Director [Member] | Unsecured Promissory Note [Member] | Other Expense [Member] | Fifth Note [Member] | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Amortization of Debt Discount (Premium) | | | | | | | | | | | | | | | | | | 3,754 | | | | | | | | | | |
Director [Member] | Unsecured Convertible Promissory Note [Member] | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Debt Instrument, Interest Rate, Stated Percentage | | | | | | 10.00% | | | | | | | | | | | | | | | | | | | | | | |
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares) | shares | | | | | | 1,000,000 | | | | | | | | | | | | | | | | | | | | | | |
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) | $ / shares | | | | | | $ 1 | | | | | | | | | | | | | | | | | | | | | | |
Debt Instrument, Unamortized Discount, Total | | | | | | $ 414,416 | | | | | | | | | | | | | | | | | | | | | | |
Warrants and Rights Outstanding, Term (Year) | | | | | | 2 years | | | | | | | | | | | | | | | | | | | | | | |
Lender Fees | | | | | | | | | | | | | | | | | | | | $ 30,000 | | | | | | | | |
Amortization of Debt Discount (Premium) | | | | | | | | | | | | | | | | | | 54,791 | | | | | | | | | | |
Director [Member] | Convertible Related Party Note Issued On July 2, 2018 [Member] | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Proceeds from Related Party Debt | | | | | $ 250,000 | | | | | | | | | | | | | | | | | | | | | | | |
Debt Instrument, Interest Rate, Stated Percentage | | | | | 10.00% | | | | | | | | | | | | | | | | | | | | | | | |
Debt Instrument, Unamortized Discount, Total | | | | | $ 103,613 | | | | | | | | | | | | | | | | | | | | | | | |
Lender Fees | | | | | $ 7,500 | | | | | | | | | | | | | | | | | | | | | | | |
Amortization of Debt Discount (Premium) | | | | | | | | | | | | | | | | | | 13,699 | | | | | | | | | | |
Director [Member] | Convertible Related Party Note Issued On July 19, 2018 [Member] | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Proceeds from Related Party Debt | | | | $ 250,000 | | | | | | | | | | | | | | | | | | | | | | | | |
Debt Instrument, Interest Rate, Stated Percentage | | | | 10.00% | | | | | | | | | | | | | | | | | | | | | | | | |
Debt Instrument, Unamortized Discount, Total | | | | $ 103,609 | | | | | | | | | | | | | | | | | | | | | | | | |
Debt Instrument, Convertible, Conversion Price (in dollars per share) | $ / shares | | | | $ 3 | | | | | | | | | | | | | | | | | | | | | | | | |
Lender Fees | | | | $ 7,500 | | | | | | | | | | | | | | | | | | | | | | | | |
Amortization of Debt Discount (Premium) | | | | | | | | | | | | | | | | | | 14,003 | | | | | | | | | | |
Director [Member] | Unsecured Convertible Related Party Note Issued On December 21, 2018 [Member] | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Proceeds from Related Party Debt | | | $ 100,000 | | | | | | | | | | | | | | | | | | | | | | | | | |
Debt Instrument, Interest Rate, Stated Percentage | | | 10.00% | | | | | | | | | | | | | | | | | | | | | | | | | |
Director [Member] | Promissory Note [Member] | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Proceeds from Related Party Debt | | | | | | | | | | | | | $ 500,000 | | | | | | | | | | | | | | | |
Debt Instrument, Interest Rate, Stated Percentage | | | | | | | | | | | | | 10.00% | | | | | | | | | | | | | | | |
Debt Instrument, Unamortized Discount, Total | | | | | | | | | | | | | $ 52,166 | | | | | | | | | | | | | | | |
Director [Member] | Promissory Note [Member] | Other Expense [Member] | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Amortization of Debt Discount (Premium) | | | | | | | | | | | | | | | | | | 6,431 | | | | | | | | | | |
Director [Member] | Warrants Issued with Debt [Member] | Measurement Input, Expected Dividend Rate [Member] | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Warrants and Rights Outstanding, Measurement Input | | | | | | | | | | | | | | | | 0 | | | | | | | | | | | | |
Director [Member] | Warrants Issued with Debt [Member] | Measurement Input, Price Volatility [Member] | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Warrants and Rights Outstanding, Measurement Input | | | | | | | | | | | | | | | | 1.842 | | | | | | | | | | | | |
Director [Member] | Warrants Issued with Debt [Member] | Measurement Input, Risk Free Interest Rate [Member] | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Warrants and Rights Outstanding, Measurement Input | | | | | | | | | | | | | | | | 0.0166 | | | | | | | | | | | | |
Director [Member] | Warrants Issued with Debt [Member] | Measurement Input, Expected Term [Member] | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Warrants and Rights Outstanding, Measurement Input | | | | | | | | | | | | | | | | 5 | | | | | | | | | | | | |
Director [Member] | Warrants Issued with Convertible Promissory Note [Member] | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares) | shares | | | | 250,000 | 250,000 | | | | | | | | | | | | | | | | | | | | | | | |
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) | $ / shares | | | | $ 1 | $ 1 | | | | | | | | | | | | | | | | | | | | | | | |
Warrants and Rights Outstanding, Term (Year) | | | | 2 years | 2 years | | | | | | | | | | | | | | | | | | | | | | | |
Director [Member] | Third Warrant [Member] | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares) | shares | | | | | | | | | | | | | | | | | | | | | | | | | | 20,000 | | |
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) | $ / shares | | | | | | | | | | | | | | | | | | | | | | | | | | $ 3 | | |
Warrants and Rights Outstanding, Term (Year) | | | | | | | | | | | | | | | | | | | | | | | | | | 5 years | | |
Director [Member] | Fifth Warrant [Member] | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares) | shares | | | | | | | 30,000 | | | | | | | | | | | | | | | | | | | | | |
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) | $ / shares | | | | | | | $ 3 | | | | | | | | | | | | | | | | | | | | | |
Warrants and Rights Outstanding, Term (Year) | | | | | | | 5 years | | | | | | | | | | | | | | | | | | | | | |
Director [Member] | Notes Payable [Member] | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Proceeds from Related Party Debt | | | | | | | | | | | $ 100,000 | | | | | $ 500,000 | | | | | | | | | | | | |
Debt Instrument, Interest Rate, Stated Percentage | | | | | | | | | | | 10.00% | | | | | 8.50% | | | | | | | | | | | | |
Debt Instrument, Unamortized Discount, Total | | | | | | | | | | | | | | | | $ 227,258 | | | | | | | | | | | | |
Debt Instrument, Convertible, Conversion Price (in dollars per share) | $ / shares | | | | | | | | | | | $ 3 | | | | $ 1.25 | | | | | | | | | | | | | |
Debt Instrument, Convertible, Number of Equity Instruments | | | | | | | | | | | | | | | 400,000 | | | | | | | | | | | | | |
Director [Member] | Notes Payable [Member] | Warrants Issued with Debt [Member] | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares) | shares | | | | | | | | | | | | | | | | 350,000 | | | | | | | | | | | | |
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) | $ / shares | | | | | | | | | | | | | | | | $ 3 | | | | | | | | | | | | |
Warrants and Rights Outstanding | | | | | | | | | | | | | | | | $ 416,618 | | | | | | | | | | | | |
Director [Member] | Consulting Agreement [Member] | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Related Party Transaction, Amounts of Transaction | | | | | | | | | | | | | | | | | $ 200,000 | | | | | | | | | | | |
General and Administrative Expense, Total | | | | | | | | | | | | | | | | | | | | | | | $ 200,000 | | | | | |
Accounts Payable, Related Parties, Current | | | | | | | | | | | | | | | | | | | | | $ 65,000 | | | | | | | |
Employee [Member] | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares) | shares | | | | | | | | | | | | | | 10,000 | | | | | | | | | | | | | | |
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) | $ / shares | | | | | | | | | | | | | | $ 3 | | | | | | | | | | | | | | |
Warrants and Rights Outstanding, Term (Year) | | | | | | | | | | | | | | 5 years | | | | | | | | | | | | | | |
Employee [Member] | Promissory Note [Member] | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Proceeds from Related Party Debt | $ 100,000 | $ 325,000 | | | | | | | | | | | | $ 100,000 | | | | | | | | | | | | | | |
Debt Instrument, Interest Rate, Stated Percentage | | | | | | | | | | | | | | 10.00% | | | | | | | | | | 12.00% | | | | |
Debt Instrument, Unamortized Discount, Total | | | | | | | | | | | | | | $ 10,435 | | | | | | | | | | | | | | |
Employee [Member] | Promissory Note [Member] | Other Expense [Member] | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Amortization of Debt Discount (Premium) | | | | | | | | | | | | | | | | | | 1,287 | | | | | | | | | | |
Rio Vista [Member] | Unsecured Promissory Note [Member] | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Proceeds from Related Party Debt | | | | | | | | | | | | $ 500,000 | | | | | | | | | | | | | | | | |
Debt Instrument, Interest Rate, Stated Percentage | | | | | | | | | | | | 10.00% | | | | | | | | | | | | | | | | |
Debt Instrument, Unamortized Discount, Total | | | | | | | | | | | | $ 50,229 | | | | | | | | | | | | | | | | |
Rio Vista [Member] | Unsecured Promissory Note [Member] | Other Expense [Member] | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Amortization of Debt Discount (Premium) | | | | | | | | | | | | | | | | | | 6,193 | | | | | | | | | | |
Rio Vista [Member] | Warrants Issued to Rio Vista [Member] | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares) | shares | | | | | | | | | | | | 50,000 | | | | | | | | | | | | | | | | |
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) | $ / shares | | | | | | | | | | | | $ 3 | | | | | | | | | | | | | | | | |
Warrants and Rights Outstanding, Term (Year) | | | | | | | | | | | | 5 years | | | | | | | | | | | | | | | | |
Investor [Member] | Unsecured Promissory Note [Member] | First Note [Member] | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Proceeds from Related Party Debt | | | | | | | | | $ 500,000 | | | | | | | | | | | | | | | | | | | |
Debt Instrument, Interest Rate, Stated Percentage | | | | | | | | | | | | | | | | | | | | | | | | | | | 10.00% | |
Debt Instrument, Unamortized Discount, Total | | | | | | | | | 35,590 | | | | | | | | | | | | | | | | | | | |
Lender Fees | | | | | | | | | 15,000 | | | | | | | | | | | | | | | | | | | |
Debt Instrument, Face Amount | | | | | | | | | $ 500,000 | | | | | | | | | | | | | | | | | | | |
Investor [Member] | Unsecured Promissory Note [Member] | Other Expense [Member] | First Note [Member] | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Amortization of Debt Discount (Premium) | | | | | | | | | | | | | | | | | | 7,016 | | | | | | | | | | |
Investor [Member] | First Warrant [Member] | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares) | shares | | | | | | | | | | | | | | | | | | | | | | | | | | | 50,000 | |
Key Employee and Principal Stockholder and Current Director [Member] | Royalty Agreement [Member] | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Deferred Compensation Arrangement with Individual, Maximum Contractual Term (Year) | | | | | | | | | | | | | | | | | | | | | 25 years | | | | | | | |
Payment of Royalties Equal to Percent of Gross Sales | | | | | | | | | | | | | | | | | | | | | 5.00% | | | | | | | |
Minimum Monthly Payment Amount to Offset Future Royalty Obligations | | | | | | | | | | | | | | | | | | | | | $ 2,500 | | | | | | | |
Prepaid Royalties, Related Party, Noncurrent | | | | | | | | | | $ 3,470 | | | | | | | | $ 3,470 | $ 0 | | | | | | | | | |
Key Employee and Principal Stockholder and Current Director [Member] | Royalty Agreement Patent Defense [Member] | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Legal Fees | | | | | | | | | | | | | | | | | | | | | $ 203,208 | | | | | | | |
Chief Operating Officer [Member] | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Lease, Cost, Total | | | | | | | | | | | | | | | | | | | | | | $ 10,000 | | | | | | |