Segment Information - Segment Information (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended	9 Months Ended
Jan. 31, 2014	Jan. 31, 2013	Jan. 31, 2014	Jan. 31, 2013
Segment Reporting Information [Line Items]
Revenues from external customers	$ 26,013	$ 27,450	$ 84,114	$ 85,318
Intersegment revenues
Earnings (loss) before income taxes	917	959	4,493	3,239
Operating Segments [Member] \| Domestic Operations [Member]
Segment Reporting Information [Line Items]
Revenues from external customers	21,544	20,445	70,678	68,757
Intersegment revenues	214	2,415	2,150	3,833
Earnings (loss) before income taxes	1,227	1,009	5,791	4,331
Operating Segments [Member] \| International Operations [Member]
Segment Reporting Information [Line Items]
Revenues from external customers	4,469	7,005	13,436	16,561
Intersegment revenues	456	454	1,704	1,876
Earnings (loss) before income taxes	678	992	1,819	2,022
Corporate [Member]
Segment Reporting Information [Line Items]
Revenues from external customers
Intersegment revenues	(670)	(2,869)	(3,854)	(5,709)
Earnings (loss) before income taxes	$ (988)	$ (1,042)	$ (3,117)	$ (3,114)

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 SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 10

-Article 5

+ Details

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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.

+ References

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