Note 12 - Employee Benefits - Non-vested Option Awards Activity (Details) - $ / shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Granted (in shares)	136,501
Granted (in dollars per share)	$ 4.34	$ 3.17	$ 3.58
Forfeited (in shares)	(16,836)
Service Based Options [Member]
Balance at beginning of period, nonvested (in shares)	444,476
Weighted average grant date fair value, beginning of period, nonvested (in dollars per share)	$ 3.46
Nonvested Contractual Life (Year)	5 years 36 days	5 years
Granted (in shares)	136,501
Granted (in dollars per share)	$ 4.34
Granted (Year)	6 years 255 days
Vested (in shares)	(151,912)
Vested (in dollars per share)	$ 3.39
Vested (Year)	3 years 146 days
Forfeited (in shares)	(15,837)
Forfeited (in dollars per share)	$ 3.19
Forfeited (Year)	4 years 109 days
Balance at end of period, nonvested (in shares)	413,228	444,476
Weighted average grant date fair value, end of period, nonvested (in dollars per share)	$ 3.79	$ 3.46