12. SEGMENT AND GEOGRAPHIC INFORMATION - Revenue (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2022 USD ($)	Sep. 30, 2021 USD ($)	Sep. 30, 2022 USD ($) segment	Sep. 30, 2021 USD ($)
Net revenues by geographic area
Net revenues	$ 8,953	$ 7,797	$ 17,862	$ 16,588
Number of reporting units | segment			1
UNITED STATES
Net revenues by geographic area
Net revenues	5,034	3,908	$ 8,601	8,442
CHINA
Net revenues by geographic area
Net revenues	310	309	1,198	630
SINGAPORE
Net revenues by geographic area
Net revenues	1,561	1,446	3,510	3,031
NETHERLANDS
Net revenues by geographic area
Net revenues	785	1,080	1,457	2,448
GERMANY
Net revenues by geographic area
Net revenues	1,015	813	2,452	1,389
Rest of the world
Net revenues by geographic area
Net revenues	$ 248	$ 241	$ 644	$ 648