XML 50 R31.htm IDEA: XBRL DOCUMENT v3.22.2
Note 3 – Marketable Securities (Tables)
 12 Months Ended
Apr. 30, 2022
Investments, Debt and Equity Securities [Abstract]  
[custom:ScheduleOfAmortizedCostNetUnrealizedGainLossFairValues]
   Cost  Unrealized Gains (Losses)  Fair Value
Money market funds  $799,047   $889   $799,936 
Asset-backed securities   2,894,512    (32,953)   2,861,559 
Corporate bonds   42,571,104    (1,442,230)   41,128,874 
Total  $46,264,663   $(1,474,294)  $44,790,369 
[custom:ScheduleOfContractualMaturitiesFairValueMeasurements]
   One Year or Less  One to
Five Years		  Over Five Years  Total
Money market funds  $799,936   $—     $—     $799,936 
Asset-backed securities   —      2,861,559    —      2,861,559 
Corporate bonds   21,702,648    18,877,593    548,633    41,128,874 
Total  $22,502,584   $21,739,152   $548,633   $44,790,369 
Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block]
   Level 1  Level 2  Level 3  Total
Money market funds  $799,936   $—     $—     $799,936 
Asset-backed securities   —      2,861,559    —      2,861,559 
Corporate bonds   —      41,128,874    —      41,128,874 
Total  $799,936   $43,990,433   $—     $44,790,369