Stockholders' Equity (Preferred Stock, Common Stock, Treasury Stock and Warrants Narrative) (Details) - USD ($)		6 Months Ended
	Sep. 06, 2018	Oct. 31, 2018	Oct. 31, 2017	Jul. 19, 2018	Apr. 30, 2018
Stockholders Equity [Line Items]
Preferred stock, shares authorized		10,000,000			10,000,000
Preferred stock, shares issued		0			0
Preferred stock, shares outstanding		0			0
Share issued in exercise of stock options		26,807
Proceeds from stock options exercised		$ 60,102	$ 53,045
Per share price		$ 0.001			$ 0.001
Stock issuance costs paid by third parties		$ 30,000
Compensation cost of unvested shares yet to be recognized, period of recognition		3 years
Chief Financial Officer [Member]
Stockholders Equity [Line Items]
Compensation cost of unvested shares yet to be recognized, period of recognition	5 years
Restricted Stock [Member] | Chief Financial Officer [Member]
Stockholders Equity [Line Items]
Restricted shares granted	25,000
Award vesting period	36 months
Compensation cost of unvested shares yet to be recognized	$ 180,000
Compensation cost of unvested shares yet to be recognized, period of recognition	36 months
Market price of company stock	$ 7.17
Cashless Exercise of Stock Options [Member]
Stockholders Equity [Line Items]
Share issued in exercise of stock options		30,764
Preferred Stock [Member]
Stockholders Equity [Line Items]
Preferred stock, shares authorized		10,000,000			10,000,000
Preferred stock, shares issued		0			0
Preferred stock, shares outstanding		0			0
Common Stock [Member]
Stockholders Equity [Line Items]
Share issued in exercise of stock options		26,807
Proceeds from stock options exercised		$ 60,102
Treasury stock repurchased				1,000,000
Per share price				$ 7.40
Sale of common stock per share price				$ 7.40
Common Stock [Member] | Cashless Exercise of Stock Options [Member]
Stockholders Equity [Line Items]
Share issued in exercise of stock options		30,764