Earnings Per Share And Stockholders' Equity (Computation Of Basic And Diluted Earnings Per Share) (Details) - USD ($)	3 Months Ended		6 Months Ended
	Oct. 31, 2017	Oct. 31, 2016	Oct. 31, 2017	Oct. 31, 2016
Earnings Per Share And Stockholders' Equity [Abstract]
Net income	$ 736,115	$ 33,295	$ 1,118,997	$ 179,892
Weighted average shares, Basic	4,201,442	4,185,752	4,198,714	4,184,854
Weighted-average shares, Effect of dilutive stock options	125,412	40,122	104,263	40,990
Weighted-average shares, Diluted	4,326,854	4,225,874	4,302,977	4,225,844
Basic earnings per share	$ 0.18	$ 0.01	$ 0.27	$ 0.04
Diluted earnings per share	$ 0.17	$ 0.01	$ 0.26	$ 0.04