Note 13 - Employee Benefits - Non-vested Option Awards Activity (Details) - $ / shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Granted, shares (in shares)	41,500
Granted, weighted average grant date fair value (in dollars per share)	$ 3.85	$ 3.93	$ 4.13
Forfeited, shares (in shares)	(12,300)
Service Based Options [Member]
Nonvested, shares (in shares)	477,980
Nonvested, weighted average grant date fair value (in dollars per share)	$ 3.45
Nonvested, weighted average remaining contractual life (Year)	4 years 9 months 18 days	5 years 1 month 6 days
Granted, shares (in shares)	41,500
Granted, weighted average grant date fair value (in dollars per share)	$ 3.85
Granted, weighted average remaining contractual life (Year)	6 years 4 months 24 days
Vested, shares (in shares)	(175,818)
Vested, weighted average grant date fair value (in dollars per share)	$ 3.07
Vested, weighted average remaining contractual life (Year)	3 years 2 months 12 days
Forfeited, shares (in shares)	(11,100)
Forfeited, weighted average grant date fair value (in dollars per share)	$ 3.43
Forfeited, weighted average remaining contractual life (Year)	4 years 3 months 18 days
Nonvested, shares (in shares)	332,562	477,980
Nonvested, weighted average grant date fair value (in dollars per share)	$ 3.71	$ 3.45