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Proceeds from the Issuance of Common Stock and Warrants, Net of Issuance Costs

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

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Basis of Presentation and Summary of Significant Accounting Policies - Narrative (Details) - USD ($) $ / shares in Units, $ in Thousands		1 Months Ended		3 Months Ended			12 Months Ended
	Nov. 29, 2019	Jan. 31, 2020	Oct. 31, 2019	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2016	Dec. 31, 2019
Concentration Risk [Line Items]
Class Of Warrant Or Right, Warrants Issued				3,682,729
Class of Warrant or Right, Exercise Price of Warrants or Rights				$ 0.125
Amount paid for clearing fees		$ 231
Offering Costs				$ 474
Proceeds from the Issuance of Common Stock and Warrants, Net of Issuance Costs				$ 2,300
Debt Instrument, Proceeds To Be Paid To Lender, Percent				10.00%
Proceeds from Issuance or Sale of Equity				$ 275
Payments on the Iliad Note				226	$ 0
Note Purchase Agreement [Member]
Concentration Risk [Line Items]
Debt Instrument, Proceeds To Be Paid To Lender, Percent	10.00%
Payments on the Iliad Note				$ 226
Institutional Investor [Member]
Concentration Risk [Line Items]
Class Of Warrant Or Right, Warrants Issued				3,441,803
Class of Warrant or Right, Exercise Price of Warrants or Rights				$ 0.674
Private Placement [Member]
Concentration Risk [Line Items]
Class Of Warrant Or Right, Warrants Issued				240,926
Class of Warrant or Right, Exercise Price of Warrants or Rights				$ 0.9988
Amount paid for placement agent commissions		193
Amount paid related to expenses for registered direct offering and concurrent private placement		$ 50
All Other Products
Concentration Risk [Line Items]
Warranty service periods			5 years
LEDFL Tubular LED Lamps (Excluding Red Caps)
Concentration Risk [Line Items]
Warranty service periods			10 years
Minimum
Concentration Risk [Line Items]
Warranty service periods						1 year
Maximum
Concentration Risk [Line Items]
Warranty service periods						5 years
Maximum \| Commercial LEDFL Tubular LED Lamps (Excluding Battery Backup TLED), Troffer Luminaires, And Certain Globe Lights
Concentration Risk [Line Items]
Warranty service periods						10 years
Customer concentration risk
Concentration Risk [Line Items]
Concentration risk (less than for one percent)				10.00%
Revenue \| Geographic concentration risk \| Countries outside of the United States
Concentration Risk [Line Items]
Concentration risk (less than for one percent)				1.00%
Distributor To The U.S. Navy \| Revenue \| Customer concentration risk
Concentration Risk [Line Items]
Concentration risk (less than for one percent)				38.00%	22.00%
Distributor To The U.S. Navy \| Accounts receivable \| Customer concentration risk
Concentration Risk [Line Items]
Concentration risk (less than for one percent)				44.00%			10.00%
Distributor for the U.S. Navy and a Regional Commercial Lighting Retrofit Company [Member] \| Revenue \| Customer concentration risk
Concentration Risk [Line Items]
Concentration risk (less than for one percent)				15.00%	30.00%
Distributor for the U.S. Navy and a Regional Commercial Lighting Retrofit Company [Member] \| Accounts receivable \| Customer concentration risk
Concentration Risk [Line Items]
Concentration risk (less than for one percent)				12.00%			41.00%
U.S. Navy and Shipbuilders [Member] \| Revenue \| Customer concentration risk
Concentration Risk [Line Items]
Concentration risk (less than for one percent)				46.00%	32.00%