Note 3 - Fair Value Measurements - Financial Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) - Fair Value, Recurring [Member] - USD ($)	Dec. 31, 2020	Dec. 31, 2019
Fair value of liabilities	$ 75,298	$ 84,596
Stock Purchase Warrants [Member]
Liability classified stock purchase warrants	75,298	84,596
Fair Value, Inputs, Level 1 [Member]
Fair value of liabilities
Fair Value, Inputs, Level 1 [Member] | Stock Purchase Warrants [Member]
Liability classified stock purchase warrants
Fair Value, Inputs, Level 2 [Member]
Fair value of liabilities
Fair Value, Inputs, Level 2 [Member] | Stock Purchase Warrants [Member]
Liability classified stock purchase warrants
Fair Value, Inputs, Level 3 [Member]
Fair value of liabilities	75,298	84,596
Fair Value, Inputs, Level 3 [Member] | Stock Purchase Warrants [Member]
Liability classified stock purchase warrants	$ 75,298	$ 84,596