Property and Equipment (Summary of Property and Equipment) (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Mar. 31, 2016
Property and equipment
Gross property and equipment	$ 33,734	$ 35,581
Less: accumulated depreciation and amortization	(19,948)	(18,577)
Net property and equipment	13,786	17,004
Land and land improvements
Property and equipment
Gross property and equipment	424	421
Buildings and building improvements
Property and equipment
Gross property and equipment	9,245	11,849
Furniture, fixtures and office equipment
Property and equipment
Gross property and equipment	7,056	7,233
Leasehold improvements
Property and equipment
Gross property and equipment	324	148
Equipment leased to customers under Power Purchase Agreements
Property and equipment
Gross property and equipment	4,997	4,997
Plant equipment
Property and equipment
Gross property and equipment	11,627	10,805
Construction in progress
Property and equipment
Gross property and equipment	$ 61	$ 128