Annual report pursuant to Section 13 and 15(d)

Summary of Significant Accounting Policies (Details)

Summary of Significant Accounting Policies (Details) $ in Thousands			3 Months Ended	12 Months Ended
	Jun. 05, 2018 USD ($) payment	Oct. 13, 2017 USD ($) payment	Mar. 31, 2018 USD ($) shares	Mar. 31, 2018 USD ($) kW shares	Mar. 31, 2017 USD ($) shares	Mar. 31, 2015 USD ($)
Changes in the accounts receivable allowances
Accounts receivable allowance, beginning balance				$ 6,845	$ 8,909
Recovery of bad debt				(1,099)	(1,525)
Bad debt write-off				(2)	(539)
Accounts receivable allowance, ending balance			$ 5,744	5,744	6,845
Inventories
Inventory allowance			5,494	5,494	6,040
Long-Lived Assets
Impairment				$ 0
Revenue
Term for advance payment from shipment of sales				90 days
Research and Development ("R&D")
Total offsets to R&D expenses				$ 0	0
Risk Concentrations
Aggregate balances that exceed insurance coverage			19,200	19,200
Bad debt recovery				1,099	$ 1,525
Bridge Bank
Summary of Significant Accounting Policies
Restricted cash equivalents for credit facility			5,000	5,000
Accounts Receivable Agreement \| Turbine International, LLC. and MTE Service
Changes in the accounts receivable allowances
Recovery of bad debt			(300)	(1,000)
Risk Concentrations
Bad debt recovery			300	1,000
Total collections on accounts receivable allowance			$ 1,000	$ 1,000
Total consideration receivable		$ 2,500
Number of payments to be received \| payment		3
Promissory Note Agreement \| Turbine International, LLC. and MTE Service
Risk Concentrations
Total consideration receivable		$ 3,800
Term of payments		3 years
Number of payments to be received \| payment		35
Amended Promissory Note Agreement \| Turbine International, LLC. and MTE Service \| Subsequent event
Risk Concentrations
Total consideration receivable	$ 3,800
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			212,392	212,392	314,537
Warrants
Net Loss Per Common Share
Antidilutive securities excluded from diluted net loss per common share computations \| shares				8,500,000	10,400,000
BPC
Risk Concentrations
Total collections on accounts receivable allowance			$ 1,800	$ 1,800
Accounts receivable			$ 5,300	$ 5,300		$ 8,100
BPC \| Subsequent event
Risk Concentrations
Number of payments to be received \| payment	5
Accounts receivable	$ 1,500
Sales \| Customer concentrations \| E-Finity
Risk Concentrations
Concentration percentage				16.00%	14.00%
Sales \| Customer concentrations \| Horizon Power Systems
Risk Concentrations
Concentration percentage					11.00%
Net accounts receivable \| Customer concentrations \| E-Finity
Risk Concentrations
Concentration percentage				18.00%	29.00%
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 \| DTC
Risk Concentrations
Concentration percentage					12.00%
Net accounts receivable \| Customer concentrations \| Reliable Secure Power Systems
Risk Concentrations
Concentration percentage					10.00%
TA100
Inventories
Inventory allowance					$ 500
Capacity of microturbine (in kW) \| kW				100
Minimum
Depreciation and Amortization
Estimated useful lives				2 years
Maximum
Depreciation and Amortization
Estimated useful lives				10 years
Warranty
Warranty period				24 months