Note 10 - Fair Value Measurements - Assets and Liabilities Measured on Recurring Basis (Details) - Fair Value, Recurring [Member] - USD ($)	Mar. 31, 2021	Dec. 31, 2020
Total assets measured and recorded at fair value	$ 1,643,358	$ 1,257,437
Fair Value, Inputs, Level 1 [Member]
Total assets measured and recorded at fair value	1,643,358	1,257,437
Fair Value, Inputs, Level 2 [Member]
Total assets measured and recorded at fair value
Fair Value, Inputs, Level 3 [Member]
Total assets measured and recorded at fair value
Cash [Member]
Cash and cash equivalents	1,611,592	1,226,045
Cash [Member] | Fair Value, Inputs, Level 1 [Member]
Cash and cash equivalents	1,611,592	1,226,045
Cash [Member] | Fair Value, Inputs, Level 2 [Member]
Cash and cash equivalents
Cash [Member] | Fair Value, Inputs, Level 3 [Member]
Cash and cash equivalents
Long-term Cash [Member]
Cash and cash equivalents	31,766	31,392
Long-term Cash [Member] | Fair Value, Inputs, Level 1 [Member]
Cash and cash equivalents	31,766	31,392
Long-term Cash [Member] | Fair Value, Inputs, Level 2 [Member]
Cash and cash equivalents
Long-term Cash [Member] | Fair Value, Inputs, Level 3 [Member]
Cash and cash equivalents