Critical Accounting Policies (Details)	6 Months Ended
	Oct. 31, 2015 USD ($)
Summary Of Critical Accounting Policies [Line Items]
Product warranty period	90 days
Goodwill impairment	$ 0
Patents [Member]
Summary Of Critical Accounting Policies [Line Items]
Estimated useful life	5 years
Trade Names [Member]
Summary Of Critical Accounting Policies [Line Items]
Estimated useful life	20 years
Backlog [Member]
Summary Of Critical Accounting Policies [Line Items]
Estimated useful life	1 year
Non-Compete Agreements [Member]
Summary Of Critical Accounting Policies [Line Items]
Estimated useful life	7 years
Customer Relationships [Member]
Summary Of Critical Accounting Policies [Line Items]
Estimated useful life	15 years