Note 13 - Fair Value of Financial Instruments - Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) - USD ($)	Sep. 30, 2021	Dec. 31, 2020
Assets:
Cash and cash equivalents	$ 0
Short-term investments	233,642
Total assets	233,642
Liabilities:
Accrued warrant liability	(945,736)
Fair Value, Recurring [Member]
Assets:
Total assets		$ 0
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Assets:
Cash and cash equivalents	0
Short-term investments
Total assets	0
Liabilities:
Accrued warrant liability	0
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Assets:
Cash and cash equivalents	0
Short-term investments	233,642
Total assets	233,642
Liabilities:
Accrued warrant liability	0
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Assets:
Cash and cash equivalents	0
Short-term investments
Total assets	0
Liabilities:
Accrued warrant liability	$ (945,736)