REVENUE (Narrative) (Details) - USD ($)	3 Months Ended		6 Months Ended		12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Mar. 31, 2020
Disaggregation Of Revenue [Line Items]
Revenues	$ 24,942,000	$ 47,696,000	$ 34,833,000	$ 89,596,000
Total revenue	26,281,000	48,322,000	$ 37,092,000	90,700,000
Percentage of contract for sale equal monthly progress payments			90.00%
Proceeds from sale of revenue earned but not billed	2,100,000	900,000	$ 2,300,000	3,700,000
Gain (loss) on sale of revenue earned but not billed	(9,000)	(23,000)	$ (9,000)	(70,000)
Revenue, Practical Expedient, Initial Application and Transition, Nondisclosure of Transaction Price Allocation to Remaining Performance Obligation [true false]			true
Revenue, Practical Expedient, Financing Component [true false]			true
Unbilled accounts receivable	21,000		$ 21,000		$ 39,000
Contract liabilities			100,000		$ 31,000
Change in contract asset reclassified to accounts receivable			0
Change in contract liability			0
Light fixture sales-type lease
Disaggregation Of Revenue [Line Items]
Total revenue	900,000	600,000	1,400,000	1,000,000
Sale of tax credits
Disaggregation Of Revenue [Line Items]
Total revenue	100,000	100,000	100,000	100,000
Legacy solar facilities
Disaggregation Of Revenue [Line Items]
Total revenue	19,000	19,000	38,000	38,000
Transferred over time
Disaggregation Of Revenue [Line Items]
Revenues	$ 0	$ 0	$ 0	$ 0