Note 11 - Fair Value Measurements - Assets and Liabilities Measured on Recurring Basis (Details) - Fair Value, Recurring [Member] - USD ($)	Jun. 30, 2020	Dec. 31, 2019
Total assets measured and recorded at fair value	$ 1,152,538	$ 1,005,624
Fair Value, Inputs, Level 1 [Member]
Total assets measured and recorded at fair value	1,152,538	1,005,624
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	1,115,332	967,212
Cash [Member] | Fair Value, Inputs, Level 1 [Member]
Cash and cash equivalents	1,115,332	967,212
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	37,206	38,412
Long-term Cash [Member] | Fair Value, Inputs, Level 1 [Member]
Cash and cash equivalents	37,206	38,412
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