Note 12 - Earnings (Loss) Per Share - Summary of Reconciliations Between the Numerator and the Denominator of the Basic and Diluted Earnings Per Share Computations (Details) - USD ($) $ / shares in Units, shares in Thousands	3 Months Ended		9 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2018	Dec. 31, 2017
Net income (loss)	$ 288,000	$ 1,107,000	$ (2,123,000)	$ 2,083,000
Shares outstanding - basic (in shares)	5,836	5,749	5,809	5,714
Earnings per share - basic (in dollars per share)	$ 0.05	$ 0.19	$ (0.37)	$ 0.36
Effect of dilutive securities on net income
Shares - dilutive securities (in shares)	26	82		60
Net income - diluted	$ 288,000	$ 1,107,000
Shares outstanding - diluted (in shares)	5,862	5,831	5,809	5,774
Earnings per share - diluted (in dollars per share)	$ 0.05	$ 0.19	$ (0.37)	$ 0.36
Shares outstanding - basic and diluted (in shares)			5,809	5,774
Earnings per share - basic and diluted (in dollars per share)			$ (0.37)	$ 0.36