Acquisitions - Additional Information (Detail) (USD $)			0 Months Ended	3 Months Ended	6 Months Ended			0 Months Ended		3 Months Ended		0 Months Ended
	Oct. 31, 2014	Apr. 30, 2014	Aug. 14, 2013 Taylor Manufacturing Systems, USA, LLC	Oct. 31, 2013 Taylor Manufacturing Systems, USA, LLC	Oct. 31, 2013 Taylor Manufacturing Systems, USA, LLC	Oct. 31, 2014 Taylor Manufacturing Systems, USA, LLC	Aug. 14, 2013 Taylor Manufacturing Systems, USA, LLC	Aug. 14, 2013 Taylor Manufacturing Systems, USA, LLC Current Technology	May 30, 2014 MID Retail, Inc.	Jul. 31, 2014 MID Retail, Inc.	May 30, 2014 MID Retail, Inc.	May 30, 2014 MID Retail, Inc. Current Technology
Business Acquisition [Line Items]
Percentage of issued and outstanding shares of capital stock											100.00%
Business acquisition, purchase price paid in cash			$ 1,191,000						$ 8,507,000
Business acquisition, working capital adjustment									678,000
Earnout period									24 months
Additional consideration payments, percentage of license fee revenues											15.00%
Additional consideration payments											1,500,000
Business acquisition costs incurred				68,500	68,500					66,800
Business acquisition, purchase price allocate to goodwill	18,749,000	13,819,000					1,218,000				4,930,000
Business acquisition, purchase price			1,841,000
Business acquisition, additional cash payments payable in each of three years following closing			200,000
Business acquisition, additional cash payments payable in first anniversary			200,000
Business acquisition, additional cash payments payable in second and third anniversaries			366,000
Business acquisition, cash payments payable in second anniversary						200,000
Business acquisition, cash payments payable in third anniversaries						$ 177,000
Remaining estimated economic life of the product								4 years				3 years