Income Taxes - Components of current and deferred federal and state income tax (benefits) provisions (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2015
Current income tax provision :
Federal	$ 71	$ 170	$ 3
State	62	50	49
Deferred income tax provision (benefits):
Federal	(166)	8,289	(655)
State	(11)	570	(213)
Net income tax (benefit) provision	$ (44)	$ 9,079	$ (816)