Note 3 - Fair Value Measurements - Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) - USD ($)	Mar. 31, 2020	Dec. 31, 2019
Cash and cash equivalents
Short-term investments	360,210	452,301
Total assets	360,210	452,301
Accrued warrant liability	44,412	6,414
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Cash and cash equivalents
Short-term investments
Total assets
Accrued warrant liability
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Cash and cash equivalents
Short-term investments	360,210	452,301
Total assets	360,210	452,301
Accrued warrant liability
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Cash and cash equivalents
Short-term investments
Total assets
Accrued warrant liability	$ 44,412	$ 6,414