Significant Accounting Policies - Additional Information (Detail)	12 Months Ended
	Mar. 31, 2020 USD ($) Derivative	Mar. 31, 2019 USD ($) Derivative
Significant Of Accounting Policies [Line Items]
Property, plant, and equipment, net	$ 4,000	$ 6,000
Allowance for doubtful accounts receivable, period increase (decrease)	2,300	(4,200)
Sales return reserve, period increase (decrease)	$ (21,000)	$ (159,000)
Foreign exchange forward contracts held | Derivative	0	0
Advertising expenses	$ 165,000	$ 121,000
Income taxes penalties		$ 3,000
Income taxes interest	0
Lease liabilities	475,000
Right-of-use assets	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