4. BALANCE SHEET DETAIL - Intangible assets (Details) - USD ($)	3 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Mar. 31, 2020
Gross Carrying Amount	$ 4,890,000		$ 4,890,000
Accumulated Amortization	(2,459,000)		(2,401,000)
Total	2,431,000		2,489,000
Amortization of intangible assets	58,000	$ 58,000
Product designs
Gross Carrying Amount	590,000		590,000
Accumulated Amortization	(590,000)		(590,000)
Patents
Gross Carrying Amount	4,220,000		4,220,000
Accumulated Amortization	(1,789,000)		(1,731,000)
Total	2,431,000		2,489,000
Software.
Gross Carrying Amount	80,000		80,000
Accumulated Amortization	$ (80,000)		$ (80,000)