Significant Accounting Policies - Additional Information (Detail)	12 Months Ended
	Mar. 31, 2021 USD ($) Derivative	Mar. 31, 2020 USD ($) Derivative
Significant Of Accounting Policies [Line Items]
Reclassified Cost And Expenses Amount		$ 1,611,500
Property, plant, and equipment, net		4,000
Allowance for doubtful accounts receivable, period increase (decrease)	$ (2,400)	2,300
Sales return reserve, period increase (decrease)	$ (17,000)	$ (21,000)
Foreign exchange forward contracts held | Derivative	0	0
Advertising expenses	$ 23,000	$ 165,000
Income taxes penalties
Income taxes interest
Lease liabilities	234,000
Right-of-use assets	213,000	$ 442,000
Office Space
Significant Of Accounting Policies [Line Items]
Lease liabilities	695,000
Right-of-use assets	$ 650,000
Minimum
Significant Of Accounting Policies [Line Items]
Credit extended periods	10 days
Maximum
Significant Of Accounting Policies [Line Items]
Credit extended periods	90 days
Microwaves
Significant Of Accounting Policies [Line Items]
Warranty period	one year period
Audio Products
Significant Of Accounting Policies [Line Items]
Warranty period	90 day period