Annual report pursuant to Section 13 and 15(d)

Note 1 - Summary of Significant Accounting Policies (Details Textual)

v3.8.0.1
Note 1 - Summary of Significant Accounting Policies (Details Textual)
12 Months Ended
Mar. 26, 2018
USD ($)
shares
Mar. 31, 2018
USD ($)
$ / shares
shares
Mar. 25, 2017
USD ($)
$ / shares
shares
Mar. 28, 2015
USD ($)
Number of Major Customers   2    
Unbilled Receivables, Not Billable, Amount Expected to be Collected in Remainder of Fiscal Year       $ 6,500,000
Revenue Recognition, Milestone Method, Revenue Recognized   $ 0 $ 478,000  
Research and Development Expense, Total   1,794,000 2,254,000  
Asset Impairment Charges, Total   $ 0 $ 0  
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross | shares   856,000 148,000  
Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price | $ / shares   $ 0.34 $ 0.97  
Accounts Receivable [Member] | Customer Concentration Risk [Member]        
Number of Major Customers   1 3  
Concentration Risk, Percentage   79.00% 67.00%  
Equity Incentive Plan 2005 [Member]        
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross | shares   400,000    
Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price | $ / shares   $ 0.33    
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized | shares   36    
Equity Incentive Plan 2005 [Member] | Employee Stock Option [Member] | Vesting on the First Anniversary of the Grant Date [Member]        
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage   25.00%    
Equity Incentive Plan 2005 [Member] | Employee Stock Option [Member] | Vesting Monthly On Each of the 36 Months Following the First Anniversary of the Grant Date [Member]        
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage   2.083%    
PFG Warrants [Member]        
Class of Warrant or Right, Cash Put Provision Eliminated $ 217,000      
Stock Issued During Period, Shares, Revaluation of Warrants | shares 150,000      
Stock Issued During Period, Value, Revaluation of Warrants $ 50,000      
Minimum [Member]        
Warranty Term   1 year    
Minimum [Member] | Machinery and Equipment [Member]        
Property, Plant and Equipment, Useful Life   3 years    
Maximum [Member]        
Warranty Term   3 years    
Maximum [Member] | Machinery and Equipment [Member]        
Property, Plant and Equipment, Useful Life   10 years