Note 8 - Restricted Stock - Non-vested Restricted Stock (Details)	12 Months Ended
	Mar. 31, 2018 shares
Non-vested restricted stock outstanding at March 31, 2017 (in shares)	232
Restricted stock granted (in shares)	79
Restricted stock vested (in shares)	(114)
Restricted stock forfeited or expired (in shares)	(4)
Non-vested restricted stock outstanding at March 31, 2018 (in shares)	193
Employee Plan [Member]
Non-vested restricted stock outstanding at March 31, 2017 (in shares)	172
Restricted stock granted (in shares)	49
Restricted stock vested (in shares)	(84)
Restricted stock forfeited or expired (in shares)	(4)
Non-vested restricted stock outstanding at March 31, 2018 (in shares)	133
Director Plan [Member]
Non-vested restricted stock outstanding at March 31, 2017 (in shares)	60
Restricted stock granted (in shares)	30
Restricted stock vested (in shares)	(30)
Restricted stock forfeited or expired (in shares)
Non-vested restricted stock outstanding at March 31, 2018 (in shares)	60