Basis of Presentation, Business Description and Summary of Significant Accounting Policies (Details Textual) $ in Thousands	12 Months Ended
May 31, 2018 USD ($) segment unit	May 31, 2017 USD ($)
Business Acquisition [Line Items]
Maturity period	less than three months
Marketable securities, at fair value \| $	$ 1,317	$ 1,215
Number of operating segments \| segment	1
Number of reporting units \| unit	1
Restocking charge percentage	20.00%
Employee Stock Option
Business Acquisition [Line Items]
Period of recognition for costs not yet recognized	4 years
Restricted Stock
Business Acquisition [Line Items]
Period of recognition for costs not yet recognized	3 years
Minimum
Business Acquisition [Line Items]
Accounts receivables period due	30 days
Estimates useful life of intangible assets other than goodwill	2 years
Undamaged product expiration date	12 months
Maximum
Business Acquisition [Line Items]
Accounts receivables period due	90 days
Estimates useful life of intangible assets other than goodwill	18 years
Building and building improvements
Business Acquisition [Line Items]
Useful life	39 years
Machinery and equipment \| Minimum
Business Acquisition [Line Items]
Useful life	5 years
Machinery and equipment \| Maximum
Business Acquisition [Line Items]
Useful life	8 years
Computer software and equipment \| Minimum
Business Acquisition [Line Items]
Useful life	3 years
Computer software and equipment \| Maximum
Business Acquisition [Line Items]
Useful life	5 years

Accounts receivable due period.

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- Definition

Number of months remaining for product to be accepted prior to expiration date of product

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Percentage of restocking charge.

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- Definition

Short term investments maturity period.

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- Definition

Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), classified as current.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=109979856&loc=d3e26626-111562

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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No definition available.

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Weighted average period over which unrecognized compensation is expected to be recognized for equity-based compensation plans, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (i)
-URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901

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Useful life of finite-lived intangible assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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- Definition

Number of operating segments. An operating segment is a component of an enterprise: (a) that engages in business activities from which it may earn revenues and incur expenses (including revenues and expenses relating to transactions with other components of the same enterprise), (b) whose operating results are regularly reviewed by the enterprise's chief operating decision maker to make decisions about resources to be allocated to the segment and assess its performance, and (c) for which discrete financial information is available. An operating segment may engage in business activities for which it has yet to earn revenues, for example, start-up operations may be operating segments before earning revenues.

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- Definition

Number of reporting units tested for impairment of goodwill. A reporting unit is an operating segment or one level below an operating segment.

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Useful life of long lived, physical assets used in the normal conduct of business and not intended for resale, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Examples include, but not limited to, land, buildings, machinery and equipment, office equipment, furniture and fixtures, and computer equipment.

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