Note 14 - Income taxes - Components of Income Tax Benefit (Expense) (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2016
Current:
Federal	$ 112	$ (2)	$ (1)
State	(2)	(3)	23
Total current benefit (expense)	110	(5)	22
Deferred:
Federal			(3,027)
State			(323)
Total deferred expense			(3,350)
Income tax benefit (expense)	$ 110	$ (5)	$ (3,328)