Goodwill And Other Intangible Assets (Narrative) (Details)	3 Months Ended			6 Months Ended		12 Months Ended
	Oct. 31, 2017 USD ($) item	Jul. 31, 2017 USD ($) item	Oct. 31, 2016 USD ($)	Oct. 31, 2017 USD ($)	Oct. 31, 2016 USD ($)	Apr. 30, 2017 USD ($)	Apr. 30, 2016 USD ($)	May 31, 2012 USD ($)
Goodwill [Line Items]
Changes in goodwill carrying amount	$ 0		$ 0	$ 0	$ 0
Goodwill	3,222,899		3,222,899	3,222,899	3,222,899	$ 3,222,899
Amortization expense	$ 107,484		$ 122,865	$ 220,075	244,280
Fully amortized year				2032
Adjustment on contingent consideration liability				$ 32,201	$ (96,627)
Spitfire [Member]
Goodwill [Line Items]
Estimated fair value of contingent consideration								$ 2,320,000
Total payment for business acquisition						273,672	$ 342,162
Adjustment on contingent consideration liability						(353,591)
Number of quarterly payments for consideration with the Spitfire aquisition | item	1	1
Quarterly payment for business acquisition	$ 66,276	$ 45,875		66,276
Contingent consideration liability	$ 443,868			$ 443,868		$ 523,818