Note 3 - Net Income Per Share - Basic and Diluted Net Income Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Jun. 30, 2022	Jun. 30, 2021
Net income (numerator):
Net income	$ 2,775	$ 4,428
Shares (denominator):
Basic (in shares)	20,208	20,109
Common shares issuable upon vesting of restricted stock (in shares)	73	81
Common shares issuable upon conversion of preferred shares (in shares)	10	10
Shares used in diluted computation (in shares)	20,291	20,200
Basic (in dollars per share)	$ 0.14	$ 0.22
Diluted (in dollars per share)	$ 0.14	$ 0.22