v3.26.1
4. BALANCE SHEET DETAIL - Intangible assets (Details) - USD ($)
 3 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Mar. 31, 2026
Finite-Lived Intangible Assets [Line Items]      
Gross Carrying Amount $ 4,890,000   $ 4,890,000
Accumulated Amortization (3,859,000)   (3,801,000)
Total 1,031,000   1,089,000
Amortization of intangible assets 58,000 $ 59,000  
Product Designs      
Finite-Lived Intangible Assets [Line Items]      
Gross Carrying Amount 590,000   590,000
Accumulated Amortization (590,000)   (590,000)
Patents      
Finite-Lived Intangible Assets [Line Items]      
Gross Carrying Amount 4,220,000   4,220,000
Accumulated Amortization (3,189,000)   (3,131,000)
Total 1,031,000   1,089,000
Software.      
Finite-Lived Intangible Assets [Line Items]      
Gross Carrying Amount 80,000   80,000
Accumulated Amortization $ (80,000)   $ (80,000)