Note 9 - Earnings Per Share - Reconciliation of Basic and Diluted Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Net income used in the computation of basic and diluted net income per share (in thousands)	$ 3,367	$ 2,376	$ 2,376
Weighted average shares outstanding - basic (in shares)	15,024,851	14,927,341	14,927,341
Dilutive common stock equivalents (in shares)	176,047		335,313
Weighted average number of shares outstanding during the period, diluted (in shares)	15,200,898	15,262,654	15,262,654
Basic (in dollars per share)	$ 0.22	$ 0.16	$ 0.16
Diluted (in dollars per share)	$ 0.22	$ 0.16	$ 0.16