4. BALANCE SHEET DETAIL - Intangible assets (Details) - USD ($)	12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2018
Gross Carrying Amount	$ 4,890,000	$ 4,890,000
Accumulated Amortization	(2,401,000)	(2,168,000)
Total	2,489,000	2,722,000
Amortization of intangible assets	233,000	267,000	$ 313,000
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	(1,731,000)	(1,498,000)
Total	2,489,000	2,722,000
Software.
Gross Carrying Amount	80,000	80,000
Accumulated Amortization	$ (80,000)	$ (80,000)