Note 17 - Segment and Related Information - Geographical Information (Details) - USD ($)	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019
Sales	$ 19,933,941	$ 21,277,797	$ 18,576,588	$ 25,281,574	$ 21,103,124	$ 22,244,681	$ 24,514,636	$ 21,836,087	$ 85,069,900	$ 89,698,527
Total sales	$ 19,933,941	$ 21,277,797	$ 18,576,588	$ 25,281,574	$ 21,103,124	$ 22,244,681	$ 24,514,636	$ 21,836,087	85,069,900	89,698,527
UNITED STATES
Sales									83,992,635	89,370,005
Total sales									83,992,635	89,370,005
PUERTO RICO
Sales									601,232
Total sales									601,232
CANADA
Sales									388,531	283,011
Total sales									388,531	283,011
Other Foreign Countries [Member]
Sales									87,502	45,511
Total sales									$ 87,502	$ 45,511