Note 14 - Stock Based Compensation - Additional Shares Authorized (Details) - shares	12 Months Ended									108 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2020
The 2010 Stock Option and Incentive Plan [Member]
Total additional shares (in shares)	365,239	233,862	106,076	12,623	7,257	5,463	4,128	2,871	2,502	740,021