Segment Information - Segment Information (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended	6 Months Ended
Oct. 31, 2014	Oct. 31, 2013	Oct. 31, 2014	Oct. 31, 2013
Segment Reporting Information [Line Items]
Revenues from external customers	$ 30,258	$ 26,098	$ 60,792	$ 58,101
Earnings (loss) before income taxes	1,895	1,152	3,740	3,576
Corporate [Member]
Segment Reporting Information [Line Items]
Intersegment revenues	(1,156)	(1,294)	(1,812)	(3,184)
Earnings (loss) before income taxes	(933)	(814)	(1,995)	(2,129)
Domestic Operations [Member] \| Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenues from external customers	23,629	22,061	47,877	49,134
Intersegment revenues	782	532	906	1,936
Earnings (loss) before income taxes	2,059	1,382	4,262	4,564
International Operations [Member] \| Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenues from external customers	6,629	4,037	12,915	8,967
Intersegment revenues	374	762	906	1,248
Earnings (loss) before income taxes	$ 769	$ 584	$ 1,473	$ 1,141

This element represents the income or loss from continuing operations attributable to the economic entity which may also be defined as revenue less expenses from ongoing operations, after income or loss from equity method investments, but before income taxes, extraordinary items, and noncontrolling interest.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 940

-SubTopic 20

-Section 25

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=35710027&loc=d3e41242-110953

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 235

-SubTopic 10

-Section S99

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 10

-Article 5

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- Definition

Amount of revenue recognized from goods sold, services rendered, insurance premiums, or other activities that constitute an earning process. Includes, but is not limited to, investment and interest income before deduction of interest expense when recognized as a component of revenue, and sales and trading gain (loss).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SX 210.5-03.1)

-URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 1

-Article 5

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- Definition

Total revenue from sale of goods and services rendered during the reporting period, in the normal course of business, reduced by sales returns and allowances, and sales discounts.

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