Annual report pursuant to Section 13 and 15(d)

Summary of Significant Accounting Policies - General Information (Details)

Summary of Significant Accounting Policies - General Information (Details)			12 Months Ended
	Jun. 05, 2018 USD ($) payment	Oct. 13, 2017 USD ($) payment	Mar. 31, 2019 USD ($) shares	Mar. 31, 2018 USD ($) shares
Changes in the accounts receivable allowances
Accounts receivable allowance, beginning balance			$ 5,744,000	$ 6,845,000
Additions charged to costs and expenses			(345,000)	(1,099,000)
Bad debt write-off			(101,000)	(2,000)
Accounts receivable allowance, ending balance			5,298,000	5,744,000
Inventories
Inventory allowance			3,887,000	5,494,000
Long-Lived Assets
Impairment			$ 0
Revenue
Practical expedient to disclose only the value of unsatisfied performance obligations for contracts with an original expected length greater than one year			true
Practical expedient to expense costs as incurred for costs to obtain a contract when the amortization period would have been one year or less			true
Research and Development ("R&D")
Total offsets to R&D expenses			$ 0
Risk Concentrations
Aggregate balances that exceed insurance coverage			29,100,000
Recovery of bad debt			345,000	$ 1,099,000
Accounts Receivable Assignment Agreement \| Turbine International, LLC. and MTE Service
Changes in the accounts receivable allowances
Additions charged to costs and expenses			(1,000,000)
Risk Concentrations
Recovery of bad debt			1,000,000
Total collections on accounts receivable allowance			1,500,000
Total consideration receivable		$ 2,500,000
Number of payments to be received \| payment		3
Payment not yet received			$ 400,000
Promissory Note Agreement \| Turbine International, LLC. and MTE Service
Risk Concentrations
Total consideration receivable		$ 3,800,000
Term of payments		3 years
Number of payments to be received \| payment		35
Amended Note Agreement \| Turbine International, LLC. and MTE Service
Risk Concentrations
Total consideration receivable	$ 3,800,000
Term of payments	3 years
Number of payments to be received \| payment	13
Stock options
Net Loss Per Common Share
Options outstanding (in shares) \| shares			174,944	212,392
Restricted stock units
Net Loss Per Common Share
Options outstanding (in shares) \| shares			2,400,000	2,000,000
Warrants
Net Loss Per Common Share
Antidilutive securities excluded from diluted net loss per common share computations \| shares			6,800,000	8,500,000
BPC
Risk Concentrations
Total collections on accounts receivable allowance			$ 1,800,000
Number of payments to be received \| payment	5
Accounts receivable	$ 1,500,000		$ 4,800,000
Revenue \| Customer concentrations \| E-Finity
Risk Concentrations
Concentration percentage			13.00%	16.00%
Revenue \| Customer concentrations \| Horizon
Risk Concentrations
Concentration percentage			12.00%
Net accounts receivable \| Customer concentrations \| E-Finity
Risk Concentrations
Concentration percentage			10.00%	18.00%
Net accounts receivable \| Customer concentrations \| Serba
Risk Concentrations
Concentration percentage				20.00%
Net accounts receivable \| Customer concentrations \| Supernova
Risk Concentrations
Concentration percentage				10.00%
Net accounts receivable \| Customer concentrations \| Reliable Secure Power Systems
Risk Concentrations
Concentration percentage			14.00%
Minimum
Depreciation and Amortization
Estimated useful lives			2 years
Maximum
Depreciation and Amortization
Estimated useful lives			10 years
Warranty
Warranty period			24 months