Note 8 - Concentration Risk (Details Textual) | 3 Months Ended | 6 Months Ended | 12 Months Ended |
Sep. 30, 2022 USD ($) | Sep. 30, 2021 | Sep. 30, 2022 USD ($) | Sep. 30, 2021 | Mar. 31, 2022 USD ($) |
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents in Excess of FDIC Insured Limits | $ 27,500,000 | | $ 27,500,000 | | $ 25,300,000 |
Maximum [Member] | | | | | |
Cash, FDIC Insured Amount | $ 250,000 | | $ 250,000 | | |
Customer Concentration Risk [Member] | Revenue Benchmark [Member] | | | | | |
Number of Customers | 3 | 3 | 3 | 3 | |
Customer Concentration Risk [Member] | Revenue Benchmark [Member] | Three Largest Customers [Member] | | | | | |
Concentration Risk, Percentage | 90% | 90% | 83% | 86% | |
Customer Concentration Risk [Member] | Revenue Benchmark [Member] | Walmart [Member] | | | | | |
Concentration Risk, Percentage | 48% | 32% | 45% | 38% | |
Customer Concentration Risk [Member] | Revenue Benchmark [Member] | Fred Meyer [Member] | | | | | |
Concentration Risk, Percentage | 24% | 19% | 22% | 21% | |
Customer Concentration Risk [Member] | Revenue Benchmark [Member] | Amazon [Member] | | | | | |
Concentration Risk, Percentage | 18% | 39% | 16% | 27% | |
Customer Concentration Risk [Member] | Accounts Receivable [Member] | | | | | |
Number of Customers | | | 3 | | 3 |
Customer Concentration Risk [Member] | Accounts Receivable [Member] | Customer One [Member] | | | | | |
Concentration Risk, Percentage | | | 42% | | 69% |
Customer Concentration Risk [Member] | Accounts Receivable [Member] | Customer Two [Member] | | | | | |
Concentration Risk, Percentage | | | 30% | | 17% |
Customer Concentration Risk [Member] | Accounts Receivable [Member] | Customer Three [Member] | | | | | |
Concentration Risk, Percentage | | | 22% | | 11% |
Product Concentration Risk [Member] | Revenue, Product and Service Benchmark [Member] | | | | | |
Number of Product Types | 2 | 2 | 2 | 2 | |
Number of Product Categories | 2 | 2 | 2 | 2 | |
Product Concentration Risk [Member] | Revenue, Product and Service Benchmark [Member] | Microwave Ovens [Member] | | | | | |
Concentration Risk, Percentage | 29% | 26% | 34% | 33% | |
Product Concentration Risk [Member] | Revenue, Product and Service Benchmark [Member] | Audio Products [Member] | | | | | |
Concentration Risk, Percentage | 70% | 73% | 65% | 67% | |
Supplier Concentration Risk [Member] | Products for Resale [Member] | | | | | |
Number of Factory Suppliers | 2 | 2 | 2 | 2 | |
Supplier Concentration Risk [Member] | Products for Resale [Member] | Two Largest Factory Suppliers [Member] | | | | | |
Concentration Risk, Percentage | 100% | 100% | 100% | 100% | |
Supplier Concentration Risk [Member] | Products for Resale [Member] | Largest Supplier [Member] | | | | | |
Concentration Risk, Percentage | 64% | 84% | 70% | 83% | |