1. THE COMPANY AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - PP&E (Details)	12 Months Ended
	Mar. 31, 2022 USD ($) segment	Mar. 31, 2021 USD ($)	Mar. 31, 2020 USD ($)
Property and equipment, net:
Useful life, property and equipment	7 years
Impairment losses on long-lived equipment	$ 0	$ 0	$ 0
Inventories
Minimum months to determine excess inventory	12 months
Inventory write-downs	$ 402,000	$ 466,000	$ 343,000
Segments
Number of operating segments | segment	1
Accounting for stock-based compensation
Expected term	5 years	5 years	5 years
Dividend yield (as a percent)	0.00%
Comprehensive income (loss)	$ (16,502,000)	$ (21,596,000)	$ (10,229,000)
Income taxes
Net deferred tax assets	16,200,000	13,000,000.0
Valuation allowance	$ 16,183,000	$ 13,017,000
Minimum
Property and equipment, net:
Useful life, intangible assets	5 years
Maximum
Property and equipment, net:
Useful life, intangible assets	15 years
Software | Minimum
Property and equipment, net:
Useful life, property and equipment	3 years
Software | Maximum
Property and equipment, net:
Useful life, property and equipment	5 years
Computer and other equipment | Minimum
Property and equipment, net:
Useful life, property and equipment	5 years
Computer and other equipment | Maximum
Property and equipment, net:
Useful life, property and equipment	10 years
Building and building improvements | Minimum
Property and equipment, net:
Useful life, property and equipment	10 years
Building and building improvements | Maximum
Property and equipment, net:
Useful life, property and equipment	25 years