Document and Entity Information (USD $)	12 Months Ended
Document and Entity Information (USD $)	May 31, 2015	Jul. 31, 2015	Nov. 28, 2014
Document And Entity Information [Abstract]
Entity Registrant Name	ANGIODYNAMICS INC
Entity Central Index Key	0001275187
Document Type	10-K
Document Period End Date	May 31, 2015
Amendment Flag	false
Document Fiscal Year Focus	2015
Document Fiscal Period Focus	FY
Current Fiscal Year End Date	--05-31
Entity Well Known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Accelerated Filer
Entity Public Float			$ 625,782,868
Entity Common Stock, Shares Outstanding		36,069,112

Consolidated Statements of Operations (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	May 31, 2015	May 31, 2014	May 31, 2013
Income Statement [Abstract]
Net sales	$ 356,974	$ 354,425	$ 341,916
Cost of sales	180,085	174,757	173,402
Gross profit	176,889	179,668	168,514
Operating expenses
Research and development	26,931	27,486	26,319
Sales and marketing	80,623	83,200	76,121
General and administrative	29,871	26,639	26,186
Amortization of intangibles	17,912	16,622	16,617
Change in fair value of contingent consideration	(8,196)	(1,808)	1,583
Acquisition, restructuring and other items, net	26,600	10,760	13,800
Medical device excise tax	4,142	3,829	1,600
Total operating expenses	177,883	166,728	162,226
Operating income (loss)	(994)	12,940	6,288
Other (expenses) income
Interest income	4	0	103
Interest expense	(3,197)	(3,656)	(5,271)
Other expense	(3,812)	(3,544)	(2,707)
Total other expenses, net	(7,005)	(7,200)	(7,875)
Income (loss) before income tax expense (benefit)	(7,999)	5,740	(1,587)
Income tax expense (benefit)	(4,731)	3,074	(376)
Net income (loss)	$ (3,268)	$ 2,666	$ (1,211)
Earnings per share
Basic (usd per share)	$ (0.09)	$ 0.08	$ (0.03)
Diluted (usd per share)	$ (0.09)	$ 0.08	$ (0.03)
Basic weighted average shares outstanding (in shares)	35,683,139	35,135,689	34,817,279
Diluted weighted average shares outstanding (in shares)	35,683,139	35,439,850	34,817,279

Consolidated Statements Comprehensive Income (Loss) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	May 31, 2015	May 31, 2014	May 31, 2013
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ (3,268)	$ 2,666	$ (1,211)
Other comprehensive (loss) income, before tax:
Unrealized gain (loss) on marketable securities	(120)	(16)	184
Unrealized gain (loss) on interest rate swap	296	(32)	(522)
Foreign currency translation gain (loss)	(411)	295	(47)
Other comprehensive income (loss), before tax	(235)	247	(385)
Income tax benefit (expense) related to items of other comprehensive income (loss)	(64)	18	125
Other comprehensive income (loss), net of tax	(299)	265	(260)
Total comprehensive income (loss), net of tax	$ (3,567)	$ 2,931	$ (1,471)

Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	May 31, 2015	May 31, 2014
CURRENT ASSETS
Cash and cash equivalents	$ 18,391	$ 16,105
Marketable securities, at fair value	1,689	1,809
Accounts receivable, net of allowances of $3,043 and $1,736, respectively	58,428	61,968
Inventories	67,388	61,234
Deferred income taxes, current	4,364	4,625
Prepaid income taxes	770	510
Prepaid expenses and other	4,783	5,471
Total current assets	155,813	151,722
Property, Plant and Equipment, net	54,560	66,590
Other Assets	5,288	4,447
Intangible Assets, net	181,806	205,256
Goodwill	361,252	360,473
Deferred Income Taxes, long term	14,904	10,403
Total Assets	773,623	798,891
Current Liabilities
Accounts payable	23,668	32,895
Accrued liabilities	18,331	17,251
Income taxes payable	439	689
Current portion of long-term debt	8,750	5,000
Current portion of contingent consideration	9,969	10,918
Total current liabilities	61,157	66,753
Long-term Debt, net of current portion	128,910	137,660
Deferred Income Taxes, long term	1,119	1,146
Contingent Consideration, net of current portion	37,415	56,413
Other Long Term Liabilities	0	84
Total Liabilities	228,601	262,056
Commitments and Contingencies (Note O)
Stockholders’ Equity
Preferred stock, par value $.01 per share, 5,000,000 shares authorized; no shares issued and outstanding	0	0
Common stock, par value $.01 per share, 75,000,000 and 45,000,000 shares authorized; 36,043,725 and 35,442,004 shares issued and outstanding at May 31, 2015 and 2014, respectively	360	353
Additional paid-in capital	520,101	508,354
Retained earnings	28,233	31,501
Treasury stock, 142,305 shares, at cost	(2,104)	(2,104)
Accumulated other comprehensive loss	(1,568)	(1,269)
Total Stockholders' Equity	545,022	536,835
Total Liabilities and Stockholders' Equity	$ 773,623	$ 798,891

Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	May 31, 2015	May 31, 2014
Statement of Financial Position [Abstract]
Accounts receivable, allowances	$ 3,043	$ 1,736
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, shares authorized	5,000,000	5,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.01	$ 0.01
Shares of common stock	75,000,000	45,000,000
Common stock, shares issued	36,043,725	35,442,004
Common stock, shares outstanding	36,043,725	35,442,004
Treasury stock, shares	142,305	142,305

Consolidated Statements of Stockholders' Equity (USD $) In Thousands, except Share data	Total	Common Stock	Additional paid in capital	Retained earnings	Accumulated other comprehensive loss	Treasury Stock
Beginning Balance at May. 31, 2012	$ 523,391	$ 348	$ 496,375	$ 30,046	$ (1,274)	$ (2,104)
Beginning Balance, Shares at May. 31, 2012		(34,826,531)				(142,305)
Net income	(1,211)			(1,211)
Exercise of stock options	5		5
Exercise of stock options, Shares		16,835
Tax effect of exercise of stock options	(1,644)		(1,644)
Issuance of performance shares, net	1	1
Issuance of performance shares, net, Shares		93,429
Purchase of common stock under Employee Stock Purchase Plan	1,211	2	1,209
Purchase of common stock under Employee Stock Purchase Plan, Shares		123,556
Purchase of common stock for treasury	(2,104)
Purchase of common stock for treasury, shares	(142,305)
Stock-based compensation	4,609		4,609
Other comprehensive loss, net of tax	(260)				(260)
Ending Balance at May. 31, 2013	526,102	351	500,554	28,835	(1,534)	(2,104)
Ending Balance, Shares at May. 31, 2013		(35,060,351)				(142,305)
Net income	2,666			2,666
Exercise of stock options	1,085		1,085
Exercise of stock options, Shares		105,676
Tax effect of exercise of stock options	(146)		(146)
Issuance of performance shares, net	(1,357)	1	(1,358)
Issuance of performance shares, net, Shares		129,702
Purchase of common stock under Employee Stock Purchase Plan	2,718	1	2,717
Purchase of common stock under Employee Stock Purchase Plan, Shares		146,275
Purchase of common stock for treasury, shares	0
Stock-based compensation	5,502		5,502
Other comprehensive loss, net of tax	265				265
Ending Balance at May. 31, 2014	536,835	353	508,354	31,501	(1,269)	(2,104)
Ending Balance, Shares at May. 31, 2014		(35,442,004)				(142,305)
Net income	(3,268)			(3,268)
Exercise of stock options	4,338		4,335
Exercise of stock options, Shares	423,804	341,446
Tax effect of exercise of stock options	0
Issuance of performance shares, net	2	2
Issuance of performance shares, net, Shares		141,274
Purchase of common stock under Employee Stock Purchase Plan	1,416	2	1,414
Purchase of common stock under Employee Stock Purchase Plan, Shares		119,001
Purchase of common stock for treasury, shares	0
Stock-based compensation	5,998		5,998
Other comprehensive loss, net of tax	(299)				(299)
Ending Balance at May. 31, 2015	$ 545,022	$ 360	$ 520,101	$ 28,233	$ (1,568)	$ (2,104)
Ending Balance, Shares at May. 31, 2015		(36,043,725)				(142,305)

Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	12 Months Ended
	May 31, 2015	May 31, 2014	May 31, 2013
Cash flows from operating activities:
Net income (loss)	$ (3,268)	$ 2,666	$ (1,211)
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation and amortization	30,492	28,157	27,227
Amortization of acquired inventory basis step-up	0	150	3,845
Tax effect of exercise of stock options and issuance of performance shares	0	(146)	(1,644)
Deferred income tax provision	(5,111)	2,951	666
Stock based compensation	5,998	5,502	4,609
Changes in accounts receivable allowances	1,448	465	338
Gain on sales of assets	0	0	(711)
Change in fair value of contingent consideration	(8,196)	(1,808)	1,583
Impairment of Long-Lived Assets Held-for-use	9,381	0	1,416
Loss on impairment of intangible assets	6,400	0	0
Other	34	(17)	157
Changes in operating assets and liabilities, net of effects of acquisitions:
Accounts receivable	2,095	(14,786)	1,020
Inventories	(6,154)	(5,608)	(1,909)
Prepaid expenses and other	(1,000)	497	977
Accounts payable and accrued liabilities	(5,877)	6,658	(9,711)
Net cash provided by operating activities	26,242	24,681	26,652
Cash flows from investing activities:
Additions to property, plant and equipment	(11,940)	(11,172)	(12,120)
Acquisition of businesses, net of cash acquired	0	(4,169)	(24,474)
Acquisition of intangible assets	(1,353)	(1,435)	(800)
Other cash flows from investing activities	0	0	801
Change in escrow receivable	0	0	2,500
Purchases of marketable securities	0	(25)	(5,134)
Proceeds from sale or maturity of marketable securities	0	353	16,989
Net cash used in investing activities	(13,293)	(16,448)	(22,238)
Cash flows from financing activities:
Repayment of long-term debt	(20,000)	(146,250)	(7,500)
Proceeds from issuance of and borrowings on long-term debt	15,000	146,410	0
Proceeds from exercise of stock options and ESPP	5,757	2,444	1,214
Payment of acquisition related contingent consideration	(11,222)	(15,943)	0
Deferred financing costs on long-term debt	0	(677)	0
Net cash used in financing activities	(10,465)	(14,016)	(6,286)
Effect of exchange rate changes on cash and cash equivalents	(198)	86	(65)
Increase (decrease) in cash and cash equivalents	2,286	(5,697)	(1,937)
Cash and cash equivalents
Beginning of year	16,105	21,802	23,739
End of year	18,391	16,105	21,802
Supplemental disclosure of non-cash operating, investing and financing activities:
Contractual obligations for acquisition of fixed assets	140	4,970	1,549
Contractual obligations for acquisition of intangibles and business	0	2,249	78,286
Cash paid during the period for:
Interest	3,151	3,591	4,936
Income taxes	699	182	200
Retained Earnings [Member]
Cash flows from operating activities:
Net income (loss)	$ (3,268)	$ 2,666	$ (1,211)

Basis of Presentation, Business Description and Summary of Significant Accounting Policies

12 Months Ended

May 31, 2015

Accounting Policies [Abstract]

BASIS OF PRESENTATION, BUSINESS DESCRIPTION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

1. Basis of Presentation and Description of Business

The consolidated financial statements include the accounts of AngioDynamics, Inc. and its wholly owned subsidiaries, (collectively, the “Company”). We design, manufacture and sell a wide range of medical, surgical and diagnostic devices used by professional healthcare providers for vascular access, for the treatment of peripheral vascular disease and in oncology and surgical settings. Our devices are generally used in minimally invasive, image-guided procedures. Most of our products are intended to be used once and then discarded, or they may be temporarily implanted for short- or long-term use.

The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the consolidated financial statements. Estimates also affect reported amounts of sales and expenses during the reporting period. Actual results could differ from those estimates.

Assets and liabilities of non-U.S. dollar functional currency entities are translated to U.S. dollars at period-end exchange rates, and the resulting gains and losses arising from the translation of those net assets are recorded as a cumulative translation adjustment, a component of accumulated other comprehensive loss on the consolidated balance sheets.

All intercompany balances and transactions have been eliminated.

Cash and Cash Equivalents

We consider all unrestricted highly liquid investments purchased with an initial maturity of less than three months to be cash equivalents. We maintain cash and cash equivalent balances with financial institutions in the United States in excess of amounts insured by the Federal Deposit Insurance Corporation.

Marketable Securities

Marketable securities, which include auction rate investments, are classified as “available-for-sale securities” and are reported at fair value, with unrealized gains and losses excluded from operations and reported as a component of accumulated other comprehensive income (loss), net of the related tax effects, in stockholders’ equity. Cost is determined using the specific identification method. We hold investments in auction rate securities in order to generate higher than typical money market rate investment returns. Auction rate securities typically are high credit quality, generally achieved with municipal bond insurance. Credit risks are eased by the historical track record of bond insurers, which back a majority of this market. Sell orders for any security traded through an auction process could exceed bids and, in such cases, the auction fails and we may be unable to liquidate our position in the securities in the near term. During fiscal years 2015 and 2014, we had $1.7 million and $1.8 million, respectively, in investments in two auction rate securities issued by New York state and local government authorities that failed auctions. The authorities are current in their interest payments on the securities.

Accounts Receivable

Accounts receivable, principally trade, are generally due within 30 to 90 days and are stated at amounts due from customers, net of an allowance for sales returns and doubtful accounts. We perform ongoing credit evaluations of our customers and adjust credit limits based upon payment history and the customer’s current creditworthiness, as determined by a review of their current credit information. We continuously monitor aging reports, collections and payments from customers, and a provision for estimated credit losses is maintained based upon our historical experience and any specific customer collection issues that have been identified. While such credit losses have historically been within our expectations and the provisions established, we cannot guarantee that the same credit loss rates will be experienced in the future. We write off accounts receivable when they are determined to be uncollectible.

Inventories

Inventories are stated at the lower of cost (using the first-in, first-out method) or market. Appropriate consideration is given to deterioration, obsolescence, expiring and other factors in evaluating net realizable value.

Property, Plant and Equipment

Property, plant and equipment are stated at cost, less accumulated depreciation. Depreciation is computed using the straight-line method over the estimated useful lives of the assets. Refer below for useful lives by category:



		Estimated useful lives
Building and building improvements		39 years
Machinery and equipment		3 to 8 years
Computer software and equipment		3 to 10 years

We evaluate these assets for impairment periodically or as changes in circumstances or the occurrence of events suggest the remaining value is not recoverable. Expenditures for repairs and maintenance are charged to expense as incurred. Renewals and betterments are capitalized.

Goodwill and Intangible Assets

Intangible assets other than goodwill and acquired IPR&D are amortized over their estimated useful lives, which range between three and fifteen years, on either a straight-line basis over the expected period of benefit or as revenues are earned from the sales of the related products. We periodically review the estimated useful lives of our intangible assets and review such assets for impairment whenever events or changes in circumstances indicate that the carrying value of the assets is not recoverable. Our determination of impairment is based on estimates of future cash flows. If an intangible asset is considered to be impaired, the amount of the impairment will equal the excess of the carrying value over the fair value of the asset.

Acquired IPR&D has an indefinite life and is not amortized until completion of the development of the project, at which time the IPR&D becomes an amortizable asset. If the related project is not completed in a timely manner or the project is terminated or abandoned, we may have an impairment related to the IPR&D, calculated as the excess of the asset’s carrying value over its fair value.

Our policy defines IPR&D as the value assigned to those projects for which the related products have not received regulatory approval and have no alternative future use. Determining the portion of the purchase price allocated to IPR&D requires us to make significant estimates. The amount of the purchase price allocated to IPR&D is determined by estimating the future cash flows of each project or technology and discounting the net cash flows back to their present values. The discount rate used is determined at the time of measurement in accordance with accepted valuation methods. These methodologies include consideration of the risk of the project not achieving commercial feasibility.

Goodwill and other intangible assets that have indefinite useful lives are not amortized, but rather, are tested for impairment annually or more frequently if impairment indicators arise. Goodwill represents the excess of the purchase price over the fair value of the net tangible and identifiable intangible assets acquired in each business combination. Goodwill and intangible assets have been recorded at either incurred or allocated cost. Allocated costs were based on respective fair market values at the date of acquisition.

For goodwill, the impairment test requires a comparison of the estimated fair value of the reporting unit to which the goodwill is assigned to the sum of the carrying value of the assets and liabilities of that unit. If the sum of the carrying value of the assets and liabilities of a reporting unit exceeds the fair value of the reporting unit, the carrying value of the reporting unit’s goodwill is reduced to its implied fair value through an adjustment to the goodwill balance, resulting in an impairment charge. Our determination of impairment is based on estimates of future cash flows.

Revenue Recognition

We recognize revenue when the following four criteria has been met: (i) persuasive evidence that an arrangement exists; (ii) the price is fixed or determinable; (iii) collectability is reasonably assured; and (iv) product delivery has occurred or services have been rendered. We recognize revenue, net of sales taxes assessed by any governmental authority, as products are shipped, based on shipping terms, and when title and risk of loss passes to customers. We negotiate shipping and credit terms on a customer-by-customer basis and products are shipped at an agreed upon price. All product returns must be pre-approved by us and customers may be subject to a 20% restocking charge. To be accepted, a returned product must be unadulterated, undamaged and have at least twelve months remaining prior to its expiration date. Charges for discounts, returns, rebates and other allowances are recognized as a deduction from revenue on an accrual basis in the period in which the revenue is recorded. The accrual for product returns, discounts and other allowances is based on the company’s history. Sales rebates are accrued by the company in the period in which the sale is recorded.

Shipping and handling costs, associated with the distribution of finished products to customers, are recorded in costs of goods sold and are recognized when the related finished product is shipped to the customer. Amounts charged to customers for shipping are recorded in net sales.

Research and Development

Research and development costs, including salaries, consulting fees, building costs, utilities and administrative expenses that are related to developing new products, enhancing existing products, validating new and enhanced products, managing clinical, regulatory and medical affairs are expensed as incurred.

Income Taxes

In preparing our financial statements, we calculate income tax expense for each jurisdiction in which we operate. This involves estimating actual current taxes due plus assessing temporary differences arising from differing treatment for tax and accounting purposes that are recorded as deferred tax assets and liabilities. We periodically evaluate deferred tax assets, capital loss carryforwards and tax credit carryforwards to determine their recoverability based primarily on our ability to generate future taxable income and capital gains. Where their recovery is not likely, we estimate a valuation allowance and record a corresponding additional tax expense in our statement of operations.

We file income tax returns in the U.S. federal jurisdiction and various state and foreign jurisdictions. In the normal course of business we are subject to examination by taxing authorities throughout the world. Fiscal years 2011 through 2015 remain open to examination by the various tax authorities. New York State is currently auditing AngioDynamic’s franchise tax filings for 2011 through 2014, and we do not anticipate any material adjustments will result. We analyzed filing positions in all of the Federal and state jurisdictions where we are required to file income taxes, as well as all open tax years in these jurisdictions and believe that our income tax filing positions and deductions will be sustained on audit and we do not anticipate any adjustments will result in a material adverse effect on our financial condition, results of operations or cash flows.

We do not anticipate that the amount of unrecognized tax benefits will significantly change in the next twelve months.

Derivative Financial Instruments

We are exposed to market risks, including changes in interest rates. We periodically enter into certain derivative financial instruments to hedge the underlying economic exposure. The derivative instruments used are floating-to-fixed rate interest rate swaps, which are subject to hedge accounting treatment.

Derivative instruments are presented in the consolidated financial statements at their fair value. Changes in the fair value of derivative financial instruments are either recognized periodically in income or in stockholders’ equity as a component of accumulated other comprehensive income (loss) depending on whether the derivative financial instrument qualifies for hedge accounting and, if so, whether it qualifies as a fair value or cash flow hedge. Generally, the changes in the fair value of derivatives accounted for as fair value hedges are recorded in income along with the portions of the changes in the fair value of hedged items that relate to the hedged risks. Changes in the fair value of derivatives accounted for as cash flow hedges, to the extent they are effective as hedges, are recorded in accumulated other comprehensive income (loss).

Supplier Concentrations

We are dependent upon the ability of our suppliers to provide products on a timely basis and on favorable pricing terms. The loss of our principal suppliers or a significant reduction in product availability from these suppliers could have a material adverse effect on us. We believe that our relationships with these suppliers are satisfactory.

Reclassification

Certain prior period disclosures have been reclassified to conform to current year presentation. These reclassifications are considered immaterial.

Recent Events

Operational Excellence Program - On December 5, 2013, we announced a company-wide operational excellence program designed to save between $15.0 and $18.0 million during the course of the next three years and expected to create greater efficiencies and drive business performance improvements. (See Note Q of Notes to Consolidated Financial Statements for more information related to the restructuring.)

Morpheus PICC recall and product line discontinuance - during the quarter ended February 28, 2015 we made a decision to voluntarily recall our Morpheus PICC product line and concurrently discontinue the product. The recall decision was made following an internal evaluation commenced as a result of communications from two international regulatory bodies which noted product complaints. Based on the evaluation performed and the lack of clear root cause, we determined the best course of action was to recall the product. Further, consistent with our strategy to transition toward our transformational BioFlo product offerings, we decided to discontinue the Morpheus line. The result was $6.1 million in charges during the year, including $4.8 million of inventory write-offs included in “Cost of sales”, as well as $1.0 million of costs associated with product returns, storage costs and other expenses which are included in “Acquisition, Restructuring and Other Items, net”.

Automated Power Injector - over the last several years we have invested in the development of a new technology which was intended to create a transformational shift in our fluid management product line. As a result of recent concerns related to an extended and difficult path to regulatory approval for the differentiating technology, we evaluated the long-term opportunity, as well as the expected risk and costs associated with bringing this technology to market. Based on that evaluation, in the quarter ended February 28, 2015 we made a decision to shift away from this technology toward other strategies and opportunities within the fluid management market. As a result we no longer expect cash flows to be generated by certain fixed assets and recorded a full impairment charge of $8.2 million in the third quarter. In addition, the sales projected on this product were a significant portion of the long-term sales projections under the NAMIC brand. The NAMIC trademark was acquired in the Navilyst Medical acquisition and was accounted for as an indefinite lived intangible asset with a value of $28.6 million at that time. Primarily as a result of the reduction in expected NAMIC product sales driven by the discontinuance of this project, we recorded an impairment charge of $6.4 in the third quarter.

EmboMedics, Inc. - on March 2, 2015, the Company filed an 8-K stating that it executed a non-binding letter of intent to enter into a strategic relationship with privately-held EmboMedics Inc., which develops injectable and resorbable embolic microspheres. On April 9, 2015 the Company entered into a License, Distribution, Manufacturing and Purchase Option Agreement with EmboMedics Inc, subject to certain approvals by EmboMedics shareholders.

Under the terms of the agreement, which has not been finalized, AngioDynamics receives an exclusive worldwide license to market and sell, upon regulatory clearances, EmboMedics’ microsphere technology. AngioDynamics will also control manufacturing of the products. AngioDynamics will make an initial $2.0 million equity investment in EmboMedics through the purchase of preferred stock. The Company may make an additional $9.0 million in equity, as well as milestone driven investments, and can execute an exclusive option to acquire EmboMedics, based on the achievement of certain milestones.

Regulatory Matters

On May 27, 2011, we received a Warning Letter from the U.S. Food and Drug Administration ("FDA") in connection with its inspection of our Queensbury, NY manufacturing facility. In the Warning Letter, FDA cited deficiencies in the response letter we provided FDA pertaining to the inspection that occurred from January 4 to January 13, 2011. The deficiencies related to our internal procedures for medical device reporting, corrections and removals and complaint handling. We responded to the Warning Letter and completed corrective and preventive actions to address the observations noted.

In December 2011, we initiated a comprehensive Quality Call to Action Program to review and augment our Quality Management Systems at our Queensbury facility. To accelerate implementation of the program, we engaged a team of external regulatory and quality experts and reallocated a significant number of engineering and product development resources to support this corporate initiative. From inception of the Quality Call to Action Program through fiscal 2014, we have incurred $3.2 million in direct costs associated with the program.

On February 10, 2012, we received from FDA a Form 483, List of Investigational Observations, in connection with its inspection of our Queensbury facility from November 14, 2011 to February 10, 2012. The Form 483 contained 12 observations related to, among other things, our CAPA (Corrective and Preventive Action) system, MDR (Medical Device Reporting), complaint investigation, corrections and removals, acceptance criteria and training. Some of the observations contained in the Form 483 were repeat observations from the May 27, 2011 Warning Letter described above.

On February 13, 2012, we received from FDA a Form 483 in connection with its inspection of our Fremont facility from January 12, 2012 to February 13, 2012. The Form 483 contained six observations related to, among other things, our CAPA system, design controls, risk management and training. We provided responses to FDA within 15 business days of our receipt of the Form 483s.

On September 24, 2012, we received from FDA a Form 483 in connection with its subsequent inspection of our Queensbury, NY facility from September 6 to September 14, and September 19 to September 24. This re-inspection followed our response to the original Form 483 issued by FDA on February 13, 2012. The Form 483 contained 5 observations related to 510(k) decisions, complaint investigations, acceptance criteria, corrective and preventive actions and training. All but one of the observations in the Form 483 related to events that occurred before the date that we had indicated to FDA in our previous responses that our corrective and remediation activities related to our Quality Call to Action would be completed. We provided responses to FDA within 15 business days of our receipt of the Form 483.

On February 4, 2014, FDA completed a comprehensive follow-up inspection of our Queensbury facility. The inspection began on January 14, 2014 and resulted in FDA issuing a Form 483 containing one observation. The observation related to the inconsistency of certain complaint investigation elements in certain devices that have hardware and disposable components. The Form 483 observation was annotated to reflect that during the inspection we had corrected the issue, and this correction was verified by the inspector. In addition, we provided a response to FDA within 15 business days of our receipt of the Form 483. We believe that the results of this inspection validate that all of the Quality System and current Good Manufacturing Practice issues raised in the 483s described above have been fully addressed.

On March 31, 2014, FDA completed an inspection of our Glens Falls, NY facility. The inspection began on March 17, 2014 and resulted in FDA issuing a form 483 containing 3 observations. The observations were related to 1) inconsistency of a manufacturing product test process used among similar products, 2) a particular verification test of a product, and 3) non-conforming product control procedure. We responded to the FDA within 15 business days of the receipt of the Form 483.

During the fourth quarter of our fiscal year ended May 31, 2014, we received Certificate to Foreign Governments ("CFGs") from the FDA covering all Vascular Access and Peripheral Vascular products manufactured in our Queensbury facility. During the first quarter of our fiscal year ending May 31, 2016, we received CFGs for our NanoKnife product.

On November 5, 2014, we received a Warning Letter from the FDA relating to observations noted during FDA’s inspection of our Navilyst Medical facilities located in Marlborough, Massachusetts and Glens Falls, New York in 2014. The matters raised in the Warning Letter and observations focused on design control processes related to packaging validations and accelerated and real time aging testing in connection with our fluid management and PICC families of products, inconsistency of a manufacturing product test process used among similar valved PICC products, a particular verification test of valved PICC products and non-conforming product control procedures. We take these matters seriously and are committed to complying with all applicable laws, regulations and rules in connection with the manufacturing, sale and marketing of our products. We made a comprehensive response to the issues raised in the letter and are committed to working with FDA to resolve all outstanding issues.

We will continue to work closely with FDA to resolve any outstanding issues. Unless the items raised in the previously disclosed Warning Letters and Form 483s are corrected to FDA’s satisfaction or we come to some other arrangement with FDA finally resolving such matters, we may be subject to additional regulatory or legal action, including the issuance of warning letters, injunction, seizure or recall of products, imposition of fines or penalties or operating restrictions on our facilities. Such actions could significantly disrupt our ongoing business and operations and have a material adverse impact on our financial position and operating results.

Recently Issued Accounting Pronouncements

In February 2013, the FASB expanded the disclosure requirements related to changes in accumulated other comprehensive income (AOCI). The new guidance requires disclosure of the amount of income (or loss) reclassified out of AOCI to each respective line item on the statement of operations where net income is presented. The guidance allows disclosure of the reclassification either in the notes to the financial statements or parenthetically on the face of the financial statements. This requirement was effective for reporting periods beginning after December 15, 2012 (fourth quarter of our fiscal year 2013). Since the guidance only impacts disclosure requirements, its adoption did not have a material impact on our consolidated financial statements.

In July 2013, the FASB issued guidance related to the presentation of certain tax information. This new pronouncement provides explicit guidance on the financial statement presentation of an unrecognized tax benefit when a net operating loss carryforward, or similar tax loss, or a tax credit carryforward exists. This pronouncement was effective for fiscal years and interim periods within those fiscal years beginning after December 15, 2013 (our fiscal year 2015). The adoption did not have a material impact on our consolidated financial statements.

In May 2014, the Financial Accounting Standards Board ("FASB") issued ASU No. 2014-09, "Revenue from Contracts with Customers" ("ASU 2014-09"). ASU 2014-09 provides a single, comprehensive accounting model for revenues arising from contracts with customers that supersedes most of the existing revenue recognition guidance, including industry-specific guidance. Under this model, revenue is recognized at an amount that an entity expects to be entitled to upon transferring control of goods or services to a customer, as opposed to when risks and rewards transfer to a customer under existing revenue recognition guidance. ASU 2014-09 is effective for the Company beginning in its fiscal year 2018, and may be applied retrospectively to all prior periods presented or through a cumulative adjustment to the opening retained earnings balance in the year of adoption. The Company is currently in the process of evaluation the impact of ASU 2014-09 on its consolidated financial statements.

In April 2015, the FASB issued ASC Update No. 2015-03, Interest-Imputation of Interest (Subtopic 835-30): Simplifying the Presentation of Debt Issuance Costs. Update No. 2015-03 requires debt issuance costs related to a recognized debt liability to be presented in the balance sheet as a direct deduction from the carrying amount of that debt liability, consistent with debt discounts. Update No. 2015-03 is effective for annual reporting periods beginning after December 15, 2015 and interim periods within those reporting periods. Early adoption is permitted for financial statements that have not been previously issued. The adoption of Update No. 2015-03 will require us to reclassify our debt issuance costs from deferred charges to direct deductions of our debt liabilities. This update is not expected to impact the results of our operations.

Our financial instruments include cash and cash equivalents, accounts receivable, marketable securities, accounts payable, interest rate swap agreement and contingent earn outs. The carrying amount of cash and cash equivalents, accounts receivable, and accounts payable approximates fair value due to the immediate or short-term maturities. The marketable securities and interest rate swap agreement has been recorded at its fair value based on a valuation received from an independent third party. The contingent earn out has been recorded at fair value using the income approach.

Fair value is the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. This policy establishes a fair value hierarchy which requires an entity to maximize the use of observable inputs and minimize the use of unobservable inputs when measuring fair value. The policy describes three levels of inputs that may be used to measure fair value which are provided in the table below.



Level 1	Quoted prices in active markets for identical assets or liabilities. Level 1 assets include money market funds that are traded in an active exchange market.



Level 2	Observable inputs other than Level 1 prices such as quoted prices for similar assets or liabilities; quoted prices in markets that are not active; or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities. When quoted market prices are unobservable, we obtain pricing information from an independent pricing vendor. The pricing vendor uses various pricing models for each asset class that are consistent with what other market participants would use. The inputs and assumptions to the model of the pricing vendor are derived from market observable sources including: benchmark yields, reported trades, broker/dealer quotes, issuer spreads, benchmark securities, bids, offers, and other market-related data. The pricing vendor considers all available market observable inputs in determining the evaluation for a security. Thus, certain securities may not be priced using quoted prices, but rather determined from market observable information. Included in Level 2 assets is our interest rate swap agreement which is valued using a mid-market valuation model.



Level 3	Unobservable inputs that are supported by little or no market activity and are significant to the fair value of the assets or liabilities. Level 3 assets and liabilities include financial instruments whose value is determined using pricing models, discounted cash flow methodologies, or similar techniques, as well as instruments for which the determination of fair value requires significant management judgment or estimation. This category includes the auction rate securities where independent pricing information was not able to be obtained and the contingent considerations related to the acquisition of Vortex, Microsulis and Clinical Devices. Our investments in auction-rate securities were classified as Level 3 as quoted prices were unavailable since these auction rate securities issued by New York state and local government authorities failed auction. Due to limited market information, we utilized a discounted cash flow (“DCF”) model to derive an estimate of fair value for contingent considerations for all periods presented. The assumptions used in preparing the DCF model included estimates with respect to the amount and timing of future interest and principal payments, forward projections of the interest rate benchmarks, the probability of full repayment of the principal considering the credit quality and guarantees in place, and the rate of return required by investors to own such securities given the current liquidity risk associated with auction-rate securities.

The following tables provide information by level for assets and liabilities that are measured at fair value (in thousands):



	Fair Value Measurements using inputs considered as:
	Level 1		Level 2		Level 3		Fair Value at May 31, 2015
Financial Assets
Marketable securities
New York State government agency obligations	$	—	$	—	$	1,689	$	1,689
Total	—		—		1,689		1,689
Total Financial Assets	$	—	$	—	$	1,689	$	1,689
Financial Liabilities
Interest rate swap agreements	$	—	$	257	$	—	$	257
Contingent liability for acquisition earn out	—		—		47,384		47,384
Total Financial Liabilities	$	—	$	257	$	47,384	$	47,641



	Fair Value Measurements using inputs considered as:
	Level 1		Level 2		Level 3		Fair Value at May 31, 2014
Financial Assets
Cash equivalents
Money market funds	$	445	$	—	$	—	$	445
Total	445		—		—		445
Marketable securities
New York State government agency obligations	—		—		1,809		1,809
Total	—		—		1,809		1,809
Total Financial Assets	$	445	$	—	$	1,809	$	2,254
Financial Liabilities
Interest rate swap agreements	$	—	$	555	$	—	$	555
Contingent liability for acquisition earn out	—		—		67,331		67,331
Total Financial Liabilities	$	—	$	555	$	67,331	$	67,886

There were no transfers in and out of Level 1, 2 and 3 measurements for the years ended May 31, 2015 and 2014.

The components of Level 3 fair value instruments as of May 31, 2015 are shown below (in thousands):



	Financial Assets			Financial Liabilities
	Fair Value Measurements Using Significant Unobservable Inputs (Level 3)			Fair Value Measurements Using Significant Unobservable Inputs
Balance at May 31, 2014	$	1,809		$	67,331
Change in fair value of contingent consideration (1)	—			(8,196		)
Currency (gain) loss from remeasurement	—			(529		)
Included in other comprehensive income (loss)	(120		)	—
Contingent consideration payments	—			(11,222		)
Balance at May 31, 2015	$	1,689		$	47,384

The components of Level 3 fair value instruments as of May 31, 2014 are shown below (in thousands):



	Financial Assets			Financial Liabilities
	Fair Value Measurements Using Significant Unobservable Inputs (Level 3)			Fair Value Measurements Using Significant Unobservable Inputs
Balance at May 31, 2013	$	1,850		$	75,049
Change in fair value of contingent consideration (1)	—			(1,808		)
New contingent consideration	—			4,970
Currency (gain) loss from remeasurement	—			—
Included in other comprehensive income (loss)	(41		)	—
Contingent consideration payments	—			(10,880		)
Balance at May 31, 2014	$	1,809		$	67,331

(1) Change in the fair value of contingent consideration is included in earning and comprised of changes in estimated earn out payments based on projections of company performance and amortization of the present value discount.

Contingent Liability for Acquisition Earn Outs

Certain of our business combinations involve the potential for the payment of future contingent consideration upon the achievement of certain product development milestones and/or various other favorable operating conditions. Payment of the additional consideration is generally contingent on the acquired company reaching certain performance milestones, including attaining specified revenue levels or achieving product development targets. Contingent consideration is recorded at the estimated fair value of the contingent milestone payments on the acquisition date. The fair value of the contingent milestone consideration is remeasured at the estimated fair value at each reporting period with the change in fair value recognized as income or expense within change in fair value of contingent consideration in the consolidated statement of operations. We measure the initial liability and remeasure the liability on a recurring basis using Level 3 inputs as defined under authoritative guidance for fair value measurements.

Contingent consideration liabilities will be remeasured to fair value each reporting period using projected net sales, discount rates, probabilities of payment and projected payment dates. Projected contingent payment amounts are discounted back to the current period using a discounted cash flow model. Projected net sales are based on our internal projections and extensive analysis of the target market and the sales potential. Increases in projected net sales and probabilities of payment may result in higher fair value measurements in the future. Increases in discount rates and the projected time to payment may result in lower fair value measurements in the future. Increases or decreases in any valuation inputs in isolation may result in a significantly lower or higher fair value measurement in the future.

The recurring Level 3 fair value measurements of the contingent consideration liabilities include the following significant unobservable inputs as of May 31, 2015 (in thousands of dollars):



	Fair value at May 31, 2015		Valuation Technique	Unobservable Input	Range
Revenue based payments	$	44,716	Discounted cash flow	Discount rate Probability of payment Projected fiscal year of payment	4% 75% - 100% 2016 - 2022
Milestone based payments	2,668		Discounted cash flow	Discount rate Probability of payment Projected fiscal year of payment	16% 75% - 100% 2017
	$	47,384

At May 31, 2015, the estimated potential amount of undiscounted future contingent consideration that we expect to pay as a result of all completed acquisitions is approximately $54.0 million. The milestones associated with the contingent consideration must be reached in future periods ranging from fiscal years 2016 to 2022 in order for the consideration to be paid.

- Definition

The entire disclosure for the organization, consolidation and basis of presentation of financial statements disclosure, and significant accounting policies of the reporting entity. May be provided in more than one note to the financial statements, as long as users are provided with an understanding of (1) the significant judgments and assumptions made by an enterprise in determining whether it must consolidate a VIE and/or disclose information about its involvement with a VIE, (2) the nature of restrictions on a consolidated VIE's assets reported by an enterprise in its statement of financial position, including the carrying amounts of such assets, (3) the nature of, and changes in, the risks associated with an enterprise's involvement with the VIE, and (4) how an enterprise's involvement with the VIE affects the enterprise's financial position, financial performance, and cash flows. Describes procedure if disclosures are provided in more than one note to the financial statements.

+ References+ Details

Acquisitions	12 Months Ended
Acquisitions	May 31, 2015
Business Combinations [Abstract]
ACQUISITIONS	ACQUISITIONS Acquisition of Clinical Devices, B.V. On August 15, 2013 we acquired all the outstanding shares of capital stock of Clinical Devices, B.V., exclusive distributor of our fluid management products in the Netherlands. The stock purchase agreement provided for the payment of $3.7 million in cash at closing, which was subject to a working capital adjustment and a $0.4 million holdback, plus future earn out consideration payable in cash. Earn out consideration is based on our net sales of the fluid management products during the five quarters following the closing as well as milestone payments for achieving regulatory approvals of certain in process research and development for a next-generation tip location technology. The total purchase consideration of $8.7 million includes an upfront payment and the estimated fair value of contingent consideration of $5.0 million. Goodwill recorded as a result of the acquisition was approximately $4.8 million and is not deductible for tax purposes. Intangible assets acquired, other than goodwill, totaled approximately $5.1 million, of which $3.6 million has been identified as in-process research and development, $1.4 million as customer relationships (15-year estimated useful life) and $0.1 million as trademarks. We also recorded a deferred tax liability of $1.2 million. The acquisition has been accounted for as a business combination and, accordingly, we have included the results of operations in the financial statements effective August 15, 2013. The pro forma effects of the acquisition on our income statement and balance sheet were not material.

- Definition

The entire disclosure for a business combination (or series of individually immaterial business combinations) completed during the period, including background, timing, and recognized assets and liabilities. The disclosure may include leverage buyout transactions (as applicable).

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+ Details

Fair Value of Financial Instruments (Notes)

12 Months Ended

May 31, 2015

Fair Value Disclosures [Abstract]

Fair Value of Financial Instruments



Level 1	Quoted prices in active markets for identical assets or liabilities. Level 1 assets include money market funds that are traded in an active exchange market.



Level 2	Observable inputs other than Level 1 prices such as quoted prices for similar assets or liabilities; quoted prices in markets that are not active; or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities. When quoted market prices are unobservable, we obtain pricing information from an independent pricing vendor. The pricing vendor uses various pricing models for each asset class that are consistent with what other market participants would use. The inputs and assumptions to the model of the pricing vendor are derived from market observable sources including: benchmark yields, reported trades, broker/dealer quotes, issuer spreads, benchmark securities, bids, offers, and other market-related data. The pricing vendor considers all available market observable inputs in determining the evaluation for a security. Thus, certain securities may not be priced using quoted prices, but rather determined from market observable information. Included in Level 2 assets is our interest rate swap agreement which is valued using a mid-market valuation model.



Level 3	Unobservable inputs that are supported by little or no market activity and are significant to the fair value of the assets or liabilities. Level 3 assets and liabilities include financial instruments whose value is determined using pricing models, discounted cash flow methodologies, or similar techniques, as well as instruments for which the determination of fair value requires significant management judgment or estimation. This category includes the auction rate securities where independent pricing information was not able to be obtained and the contingent considerations related to the acquisition of Vortex, Microsulis and Clinical Devices. Our investments in auction-rate securities were classified as Level 3 as quoted prices were unavailable since these auction rate securities issued by New York state and local government authorities failed auction. Due to limited market information, we utilized a discounted cash flow (“DCF”) model to derive an estimate of fair value for contingent considerations for all periods presented. The assumptions used in preparing the DCF model included estimates with respect to the amount and timing of future interest and principal payments, forward projections of the interest rate benchmarks, the probability of full repayment of the principal considering the credit quality and guarantees in place, and the rate of return required by investors to own such securities given the current liquidity risk associated with auction-rate securities.

The following tables provide information by level for assets and liabilities that are measured at fair value (in thousands):



	Fair Value Measurements using inputs considered as:
	Level 1		Level 2		Level 3		Fair Value at May 31, 2015
Financial Assets
Marketable securities
New York State government agency obligations	$	—	$	—	$	1,689	$	1,689
Total	—		—		1,689		1,689
Total Financial Assets	$	—	$	—	$	1,689	$	1,689
Financial Liabilities
Interest rate swap agreements	$	—	$	257	$	—	$	257
Contingent liability for acquisition earn out	—		—		47,384		47,384
Total Financial Liabilities	$	—	$	257	$	47,384	$	47,641



	Fair Value Measurements using inputs considered as:
	Level 1		Level 2		Level 3		Fair Value at May 31, 2014
Financial Assets
Cash equivalents
Money market funds	$	445	$	—	$	—	$	445
Total	445		—		—		445
Marketable securities
New York State government agency obligations	—		—		1,809		1,809
Total	—		—		1,809		1,809
Total Financial Assets	$	445	$	—	$	1,809	$	2,254
Financial Liabilities
Interest rate swap agreements	$	—	$	555	$	—	$	555
Contingent liability for acquisition earn out	—		—		67,331		67,331
Total Financial Liabilities	$	—	$	555	$	67,331	$	67,886

There were no transfers in and out of Level 1, 2 and 3 measurements for the years ended May 31, 2015 and 2014.

The components of Level 3 fair value instruments as of May 31, 2015 are shown below (in thousands):



	Financial Assets			Financial Liabilities
	Fair Value Measurements Using Significant Unobservable Inputs (Level 3)			Fair Value Measurements Using Significant Unobservable Inputs
Balance at May 31, 2014	$	1,809		$	67,331
Change in fair value of contingent consideration (1)	—			(8,196		)
Currency (gain) loss from remeasurement	—			(529		)
Included in other comprehensive income (loss)	(120		)	—
Contingent consideration payments	—			(11,222		)
Balance at May 31, 2015	$	1,689		$	47,384

The components of Level 3 fair value instruments as of May 31, 2014 are shown below (in thousands):



	Financial Assets			Financial Liabilities
	Fair Value Measurements Using Significant Unobservable Inputs (Level 3)			Fair Value Measurements Using Significant Unobservable Inputs
Balance at May 31, 2013	$	1,850		$	75,049
Change in fair value of contingent consideration (1)	—			(1,808		)
New contingent consideration	—			4,970
Currency (gain) loss from remeasurement	—			—
Included in other comprehensive income (loss)	(41		)	—
Contingent consideration payments	—			(10,880		)
Balance at May 31, 2014	$	1,809		$	67,331

Contingent Liability for Acquisition Earn Outs

The recurring Level 3 fair value measurements of the contingent consideration liabilities include the following significant unobservable inputs as of May 31, 2015 (in thousands of dollars):



	Fair value at May 31, 2015		Valuation Technique	Unobservable Input	Range
Revenue based payments	$	44,716	Discounted cash flow	Discount rate Probability of payment Projected fiscal year of payment	4% 75% - 100% 2016 - 2022
Milestone based payments	2,668		Discounted cash flow	Discount rate Probability of payment Projected fiscal year of payment	16% 75% - 100% 2017
	$	47,384

Marketable Securities and Investments

12 Months Ended

May 31, 2015

Investments, Debt and Equity Securities [Abstract]

MARKETABLE SECURITIES AND INVESTMENTS

As of May 31, 2015, marketable securities consisted of the following:



	Amortized cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
	(in thousands)
Available-for-sales securities
New York State government agency obligations	$	1,825	$	—	$	(136	)	$	1,689
	$	1,825	$	—	$	(136	)	$	1,689

As of May 31, 2014, marketable securities consisted of the following:



	Amortized cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
	(in thousands)
Available-for-sales securities
New York State government agency obligations	$	1,825	$	—	$	(16	)	$	1,809
	$	1,825	$	—	$	(16	)	$	1,809

The amortized cost and fair value of marketable securities as of May 31, 2015, by contractual maturity, are shown below. Expected maturities may differ from contractual maturities because borrowers may have the right to call or prepay obligations with or without call or prepayment penalties.



	Amortized cost		Fair Value
	(in thousands)
As of May 31, 2015:
Due in one year or less	$	—	$	—
Due after one through five years	—		—
Due after five through twenty years	1,825		1,689
	$	1,825	$	1,689

- Definition

The entire disclosure for investments in certain debt and equity securities.

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+ Details

Inventories

12 Months Ended

May 31, 2015

Inventory Disclosure [Abstract]

INVENTORIES

As of May 31, 2015 and 2014, inventories consisted of the following:



	May 31, 2015		May 31, 2014
	(in thousands)
Raw materials	$	28,040	$	24,734
Work in process	11,910		11,992
Finished goods	27,438		24,508
Total	$	67,388	$	61,234

- Definition

The entire disclosure for inventory. This may include, but is not limited to, the basis of stating inventory, the method of determining inventory cost, the major classes of inventory, and the nature of the cost elements included in inventory. If inventory is stated above cost, accrued net losses on firm purchase commitments for inventory and losses resulting from valuing inventory at the lower-of-cost-or-market may also be included. For LIFO inventory, may disclose the amount and basis for determining the excess of replacement or current cost over stated LIFO value and the effects of a LIFO quantities liquidation that impacts net income.

+ References+ Details

Property, Plant and Equipment, at Cost

12 Months Ended

May 31, 2015

Property, Plant and Equipment [Abstract]

PROPERTY, PLANT AND EQUIPMENT, AT COST

Property, plant and equipment are summarized as follows:



	May 31, 2015			May 31, 2014
	(in thousands)
Building and building improvements	$	33,853		$	33,126
Machinery and equipment	23,626			31,880
Computer software and equipment	24,431			25,836
Construction in progress	7,143			12,564
	89,053			103,406
Less accumulated depreciation and amortization	(36,197		)	(37,845		)
	52,856			65,561
Land and land improvements	1,704			1,029
	$	54,560		$	66,590

Depreciation expense for fiscal 2015, 2014 and 2013 was $9.8 million, $8.4 million and $8.7 million, respectively. In conjunction with the Operational Excellence Program that was announced in December 2013, we updated the estimated useful lives on certain manufacturing equipment. As a result of the change in the useful life, we recoded additional depreciation of $1.5 million, $0.8 million and $0 million for the years ended May 31, 2015, 2014 and 2013, respectively. There was also an impairment of fixed assets, refer to Note A.

- Definition

The entire disclosure for long-lived, physical assets used in the normal conduct of business and not intended for resale. Includes, but is not limited to, accounting policies and methodology, roll forwards, depreciation, depletion and amortization expense, including composite depreciation, accumulated depreciation, depletion and amortization expense, useful lives and method used, income statement disclosures, assets held for sale and public utility disclosures.

+ References+ Details

Goodwill and Intangible Assets

12 Months Ended

May 31, 2015

Goodwill and Intangible Assets Disclosure [Abstract]

GOODWILL AND INTANGIBLE ASSETS

We consider our business to be a single operating segment entity as further described in Note P.

Determining the fair value of a reporting unit is judgmental in nature and requires the use of significant estimates and assumptions, including revenue growth rates, operating margins, discount rates and future market conditions, among others. These assumptions are highly sensitive and changes in these estimates could result in impairment. To determine the fair value of our reporting unit, we considered two market-based approaches and an income approach. Under the market-based approaches, we utilized information regarding our own as well as publicly available industry information to determine earnings multiples and sales multiples. Under the income approach, we determined fair value based on estimated future cash flows of the reporting unit, discounted by an estimated weighted-average cost of capital, which reflects the overall level of inherent risk of a reporting unit and the rate of return an outside investor would expect to earn. We determined the discounted cash flow as the best indicator to determine fair value and therefore assigned a weight of 75% with the remaining 25% assigned to the market approach.

Solely for purposes of establishing inputs for the fair value calculations, we assumed that the current economic conditions would continue through fiscal year 2015. In addition, we applied gross margin assumptions, showing some improvement over historical trends, at various revenue levels and used a capitalization rate of 8% to calculate the terminal value of the reporting unit. In addition, we used a discount rate of 12% to calculate the fair value of our reporting unit. The fair value of the reporting unit was reconciled to our current stock market capitalization as of December 31, 2014.

We completed our annual goodwill impairment test as of December 31, 2014. At December 31, 2014, our reporting unit is the same as our reportable segment. Our assessment of goodwill impairment indicated that the fair value of our reporting unit exceeded its carrying value and therefore goodwill was not impaired. The fair value of our reporting unit exceeded its carrying value by 18%.

Our stock market capitalization has at times been lower than our shareholders’ equity or book value. However, our reporting unit has continued to generate significant cash flows from operations, and we expect to continue to do so in fiscal 2016 and beyond. Furthermore, we believe that a reasonable potential buyer would offer a control premium for our business that would adequately cover the difference between our stock market capitalization and our book value.

Even though we determined that there was no goodwill impairment as of December 31, 2014, the future occurrence of a potential indicator of impairment, such as a significant adverse change in legal factors or business climate, an adverse action or assessment by a regulator, unanticipated competition, a material negative change in relationships with significant customers, strategic decisions made in response to economic or competitive conditions, loss of key personnel or a more-likely-than-not expectation that the reporting unit or a significant portion of the reporting unit will be sold or disposed of, would require an interim assessment for the reporting unit prior to the next required annual assessment as of December 31, 2015.

It is not possible at this time to determine if any such future impairment charge would result or, if it does, whether such charge would be material. Events that could, in the future, result in impairment include, but are not limited to, declining sales for a significant product or in a significant geographic region.

We also completed our annual indefinite lived asset (NAMIC trademark) impairment test as of December 31, 2014 using the income approach to determine fair value. Under this approach, the relief from royalty method was applied using a 3% long-term growth rate, a 3% royalty rate and a 12% discount rate. Our assessment of the NAMIC trademark indicated that the carrying value exceeded the fair value by $6.4 million; therefore, the asset was impaired and a $6.4 million impairment charge was recorded during the third quarter of 2015. We also re-evaluated the NAMIC trademark at February 28, 2015 and determined that it is no longer an indefinite-lived intangible. We have assigned it a remaining useful life of 12 years, consistent with customer relationships, and began amortization.

As of May 31, 2015 and 2014, intangible assets consisted of the following:



	May 31, 2015
	Gross carrying value		Accumulated amortization			Net carrying value		Weighted average useful life
	(in thousands)							(years)
Product technologies	$	148,776	$	(41,447	)	$	107,329	10.2
Customer relationships	86,371		(42,813		)	43,558		12.0
Trademarks	28,545		(3,229		)	25,316		10.7
In process R&D Acquired	3,600		—			3,600		Indefinite
Licenses	7,913		(5,910		)	2,003		8.3
Distributor relationships	900		(900		)	—		3.0
	$	276,105	$	(94,299	)	$	181,806



	May 31, 2014
	Gross carrying value		Accumulated amortization			Net carrying value		Weighted avg useful life
	(in thousands)							(years)
Product technologies	$	150,298	$	(32,930	)	$	117,368	10.2
Customer relationships	86,645		(37,848		)	48,797		11.9
Trademark—NAMIC	28,600		—			28,600		Indefinite
In process R&D Acquired	3,600		—			3,600		Indefinite
Licenses	7,639		(5,211		)	2,428		8.4
Trademarks	6,345		(1,882		)	4,463		8.0
Distributor relationships	900		(900		)	—		3.0
	$	284,027	$	(78,771	)	$	205,256

Amortization expense was $17.9 million, $16.6 million and $16.6 million for fiscal 2015, 2014 and 2013, respectively.

Annual amortization of these intangible assets is expected to approximate the following amounts for each of the next five fiscal years (in thousands):



2016	$	18,452
2017	$	18,568
2018	$	19,388
2019	$	21,499
2020	$	22,741

Adjustments to goodwill for the fiscal year ended May 31, 2015 and May 31, 2014 are as follows (in thousands):



	Total
Balance, May 31, 2013	$	355,637
Acquisition of Clinical Devices B.V.	4,836
Balance, May 31, 2014	$	360,473
Tax basis adjustment	779
Balance, May 31, 2015	$	361,252

During fiscal 2015, goodwill and deferred tax liabilities were adjusted by $0.8 million due to the receipt of a New York State tax grant that was not correctly accounted for as part of purchase accounting in fiscal 2012. The Company has determined that this adjustment was not material to any current or prior annual or interim periods. During fiscal 2014, the change in the carrying value of goodwill is the result of the acquisition of Clinical Devices, B.V. (See Note B.) During the fourth quarter of fiscal 2014, there was an adjustment of $0.5 million to the carrying value of such goodwill related to working capital.

- Definition

The entire disclosure for the aggregate amount of goodwill and a description of intangible assets, which may include (a) for amortizable intangible assets (also referred to as finite-lived intangible assets), the carrying amount, the amount of any significant residual value, and the weighted-average amortization period, (b) for intangible assets not subject to amortization (also referred to as indefinite-lived intangible assets), the carrying amount, and (c) the amount of research and development assets acquired and written off in the period, including the line item in the income statement in which the amounts written off are aggregated, if not readily apparent from the income statement. Also discloses (a) for amortizable intangibles assets in total and by major class, the gross carrying amount and accumulated amortization, the total amortization expense for the period, and the estimated aggregate amortization expense for each of the five succeeding fiscal years, (b) for intangible assets not subject to amortization the carrying amount in total and by major class, and (c) for goodwill, in total and for each reportable segment, the changes in the carrying amount of goodwill during the period (including the aggregate amount of goodwill acquired, the aggregate amount of impairment losses recognized, and the amount of goodwill included in the gain (loss) on disposal of a reporting unit). If any part of goodwill has not been allocated to a reportable segment, discloses the unallocated amount and the reasons for not allocating. For each impairment loss recognized related to an intangible asset (excluding goodwill), discloses: (a) a description of the impaired intangible asset and the facts and circumstances leading to the impairment, (b) the amount of the impairment loss and the method for determining fair value, (c) the caption in the income statement or the statement of activities in which the impairment loss is aggregated, and (d) the segment in which the impaired intangible asset is reported. For each goodwill impairment loss recognized, discloses: (a) a description of the facts and circumstances leading to the impairment, (b) the amount of the impairment loss and the method of determining the fair value of the associated reporting unit, and (c) if a recognized impairment loss is an estimate not finalized and the reasons why the estimate is not final. May also disclose the nature and amount of any significant adjustments made to a previous estimate of an impairment loss.

+ References+ Details

Income Taxes

12 Months Ended

May 31, 2015

Income Tax Disclosure [Abstract]

INCOME TAXES

-INCOME TAXES

The components of income (loss) before income tax provision for the years ended May 31 are as follows:



	2015			2014		2013
	(in thousands)
(Loss) income before tax provision:
US	$	(8,833	)	$	5,199	$	(3,614	)
Non-US	834			541		2,027
	$	(7,999	)	$	5,740	$	(1,587	)

Income tax (benefit) provision analyzed by category and by statement of operations classification for the years ended May 31 is summarized as follows:



	2015			2014			2013
	(in thousands)
Current
Federal	$	(242	)	$	(133	)	$	(1,622	)
State and local	205			99			(52		)
Non U.S.	417			157			468
	380			123			(1,206		)
Deferred	(5,111		)	2,951			830
Income tax (benefit) provision	$	(4,731	)	$	3,074		$	(376	)

The significant components of deferred income tax (benefit) expense from operations for the years ended May 31 consist of the following:



	2015			2014		2013
	(in thousands)
Deferred tax benefit	$	(1,916	)	$	1,778	$	830
Impact of NYS tax reform legislation	—			1,173		—
Net operating loss carryforward	(3,195		)	—		—
	$	(5,111	)	$	2,951	$	830

Temporary differences that give rise to deferred tax assets and liabilities are summarized as follows:



	May 31, 2015			May 31, 2014
	(in thousands)
Deferred tax assets
Net operating loss carryforward	$	51,785		$	48,749
Stock-based compensation	4,468			4,851
Federal and state R&D tax credit carryforward	1,646			1,249
Inventories	2,808			875
Expenses incurred not currently deductible	2,107			1,379
Accrued liabilities	114			154
Gross deferred tax asset	62,928			57,257
Deferred tax liabilities
Excess tax over book depreciation and amortization	42,988			41,843
	42,988			41,843
Valuation Allowance	(1,791		)	(1,532		)
Net deferred tax asset	$	18,149		$	13,882

At May 31, 2015, we had approximately $173.7 million of remaining Federal net operating loss carryforwards and $34.8 million of state net operating loss carryforwards (“NOL”). Approximately $161.5 million of our Federal net operating loss was generated by acquired companies and are subject to Internal Revenue Code (“IRC”) Section 382 limitations which are expected to limit our ability to utilize these net operating losses on an annual basis. As a result of our IRC Section 382 analyses, it is estimated that approximately $26.1 million of remaining Federal net operating losses and $5.4 million of state net operating losses will expire prior to utilization. The gross deferred income tax asset (“DTA”) related to the NOL reflects these limitations.

Our Federal net operating loss carryforwards as of May 31, 2015 after considering IRC Section 382 limitations are $147.6 million. The expiration of the Federal net operating loss carryforwards are as follows: $30.7 million between 2017 and 2026 and $116.9 million between 2027 and 2033.

Our state net operating loss carryforwards as of May 31, 2015 after considering remaining IRC Section 382 limitations are $29.4 million which expire in various years from 2015 to 2033.

As a result of certain realization requirements of ASC 718, the table of deferred tax assets and liabilities shown above does not include certain deferred tax assets as of May 31, 2015 and 2014 that arose directly from tax deductions related to equity compensation greater than compensation recognized for financial reporting. Equity will be increased by $0.3 million if and when such excess tax benefits are ultimately realized.

At May 31, 2015, we had a net deferred income tax asset of $18.1 million, after recording a valuation allowance of $1.8 million. The valuation allowance increased by $0.3 million in 2015 and increased by $0.8 million in 2014. The 2015 change principally relates to the true-up of our fiscal 2014 tax filings and management’s reevaluation of the expected utilization of state net operating losses based on revised projections of taxable income. The 2014 change relates to the true-up of our fully reserved capital losses and state tax credits and net operating losses from our fiscal 2013 tax filings. The valuation allowance recorded against the deferred tax assets relates to state tax credits and state NOLs that management has estimated will more likely than not expire before they are expected to be utilized.

The Company’s analysis of the need for a valuation allowance considered that the Company has incurred a cumulative loss in the U.S. over the three year period ended May 31, 2015. A majority of the cumulative loss has been caused by the charges associated with the product recall and discontinuance and the impairment of fixed and intangible assets recorded in the quarter end February 28, 2015, as well as restructuring and integration expenses in the period since the acquisition of Navilyst Medical in May 2012. We anticipate a return to profitability in fiscal 2016. Consideration has also been given to our history of not having Federal tax loss carryforwards expire unused, as well as the period over which the net deferred tax assets can be realized, including the expiration of our loss carryforwards and IRC Section 382 limitations.

Based on our assessment, it is more likely than not that our U.S. net deferred tax asset will be realized through future taxable earnings, the reversal of existing taxable temporary differences, and tax planning strategies. Accordingly no valuation allowance has been recorded on this net asset. We will continue to assess the need for a valuation allowance in the future.

If future results are less than projected in the U.S. and if tax planning alternatives do not offset those effects, a valuation allowance may be required to reduce the deferred tax asset, which could have a material impact on our results of operations in the period in which it is recorded. While the net deferred tax asset at May 31, 2015 is $19.3 million, if the Company were required to record a valuation allowance it could be $15.3 million greater than this amount due to deferred tax liabilities related to intangibles that have an indefinite reversal period.

Our consolidated income tax provision has differed from the amount that would be provided by applying the U.S. Federal statutory income tax rate to our income before income taxes for the following reasons:



	2015			2014			2013
	(in thousands)
Income tax (benefit) provision at statutory tax rate of 35%	$	(2,800	)	$	2,008		$	(555	)
Effect of graduated tax rates	80			(57		)	(16		)
State income taxes, net of Federal tax benefit	(17		)	122			95
State income tax credits, net of Federal tax benefit	—			—			(23		)
Impact of Non US operations	133			(27		)	(228		)
Research and development tax credit	(604		)	(236		)	(142		)
Nondeductible acquisition costs	—			—			110
Nondeductible interest on contingent payments	265			540			130
Nontaxable gain on revaluation of contingent consideration liability	(3,138		)	(1,698		)	—
Tax law changes	(454		)	1,173			—
Effect of elimination of stock compensation APIC pool	1,253			440			—
Nondeductible stock-based compensation	—			176			108
Other nondeductible expenses	498			384			336
Over (under) accrual of prior year Federal and state taxes	38			249			(10		)
Fully reserved capital losses	—			—			(179		)
Other	15			—			(2		)
Income tax (benefit) expense	$	(4,731	)	$	3,074		$	(376	)

There were no uncertain tax positions as of May 31, 2015, 2014 and 2013.

We recognize interest and penalties related to unrecognized tax benefits within our global operations as a component of income tax expense. There were no accrued interest and penalties recognized in the consolidated balance sheet as of May 31, 2015 and May 31, 2014.

Fiscal years 2011 through 2015 remain open to examination by the various tax authorities. New York State is currently auditing AngioDynamic's franchise tax filings for 2011 through 2013, and we do not anticipate any material adjustments will result. We analyzed filing positions in all of the Federal and state jurisdictions where we are required to file income taxes, as well as all open tax years in these jurisdictions and believe that our income tax filing positions and deductions will be sustained on audit and we do not anticipate any adjustments will result in a material adverse effect on our financial condition, results of operations or cash flows.

We do not anticipate that the amount of unrecognized tax benefits will significantly change in the next twelve months.

The accumulated undistributed earnings of the Company’s foreign operations were approximately $4 million, and are intended to remain indefinitely invested in foreign operations. Accordingly, no taxes have been provided on these earnings at May 31, 2015. If these earnings were distributed, the Company would be subject to both foreign withholding taxes and U.S. income taxes that may not be fully offset by foreign tax credits. A reasonable estimate of the deferred tax liability on these earnings is not practicable at this time.

- Definition

The entire disclosure for income taxes. Disclosures may include net deferred tax liability or asset recognized in an enterprise's statement of financial position, net change during the year in the total valuation allowance, approximate tax effect of each type of temporary difference and carryforward that gives rise to a significant portion of deferred tax liabilities and deferred tax assets, utilization of a tax carryback, and tax uncertainties information.

+ References+ Details

Long-Term Debt

12 Months Ended

May 31, 2015

Debt Disclosure [Abstract]

LONG-TERM DEBT

On September 19, 2013, we entered into a Credit Agreement (the "Credit Agreement") with the lenders party thereto, JPMorgan Chase Bank, N.A., as administrative agent, Bank of America, N.A. and Keybank National Association as co-syndication agents, and J.P. Morgan Securities LLC, Merrill Lynch, Pierce, Fenner & Smith Incorporated and Keybank National Association as joint bookrunners and joint lead arrangers.

The Credit Agreement provides for a $100 million senior secured term loan facility (the "Term Loan") and a $100 million senior secured revolving credit facility, which includes up to a $20 million sublimit for letters of credit and a $5 million sublimit for swingline loans (the "Revolving Facility", and together with the Term Loan, the "Facilities").

The proceeds of the Revolving Facility may be used for general corporate purposes of AngioDynamics and its subsidiaries. The Facilities have a five years maturity. The Term Loan has a quarterly repayment schedule equal to 5%, 5%, 10%, 15% and 65% of its principal amount in years one through five. Interest on both the Term Loan and Revolving Facility will be based on a base rate or Eurodollar rate plus an applicable margin which increases as our total leverage ratio increases, with the base rate and Eurodollar rate having ranges of 0.5% to 1.25% and 1.5% to 2.25% respectively. After default, the interest rate may be increased by 2.0%. The Revolving Facility will also carry a commitment fee of 0.2% to 0.35% per annum on the unused portion.

Our obligations under the Facilities are unconditionally guaranteed, jointly and severally, by our material direct and indirect domestic subsidiaries (the "Guarantors"). All obligations of AngioDynamics and the Guarantors under the Facilities are collateralized by first priority security interests in substantially all of the assets of AngioDynamics and the Guarantors.

We have entered in an interest rate swap agreement, (the "Swap Agreement"), with an initial notional amount of $100 million, to limit the effect of rising of interest rates. The Swap Agreement, which qualified for hedge accounting under authoritative guidance, was a contract to exchange floating interest rate payments for fixed interest rate payments of 3.26% on the outstanding balance of the loan over the life of the agreement without the exchange of the underlying notional amounts. The Swap Agreement provides for a fixed rate of 0.74% above the applicable rate provided for in the Credit Agreement. The SWAP matures during 2016.

On September 19, 2013, we borrowed $100 million under the Term Facility and approximately $41.4 million under the Revolving Facility to repay the Prior Credit Agreement. As of May 31, 2015, $91.3 million and $46.4 million were outstanding under the Term Facility and Revolving Facility, respectively. The Credit Agreement includes customary representations, warranties and covenants, and acceleration, indemnity and events of default provisions, including, among other things, two financial covenants. The first financial covenant requires us to maintain, as of the end of each of our fiscal quarters, a ratio of (i) consolidated EBITDA minus consolidated capital expenditures to (ii) consolidated interest expense paid or payable in cash plus scheduled principal payments in respect of indebtedness under the Credit Agreement of not less than 1.35 to 1.00. The second financial covenant requires us to maintain, as of the end of each of our fiscal quarters, a ratio of consolidated total indebtedness to consolidated EBITDA of not greater than 3.75 to 1.00. We were in compliance with both financial covenants as of May 31, 2015.

As of May 31, 2015, future minimum principal payments on long-term debt were as follows (in thousands):



2016	$	8,750
2017	13,750
2018	26,250
2019	88,910
2020	—
	$	137,660

Retirement Plans	12 Months Ended
Retirement Plans	May 31, 2015
Compensation and Retirement Disclosure [Abstract]
RETIREMENT PLANS	RETIREMENT PLANS We have a 401(k) plan under which eligible employees can defer a portion of their compensation, part of which is matched by us. Matching contributions were $3.7 million, $2.8 million and $2.5 million in 2015, 2014 and 2013, respectively. There are also various immaterial foreign retirement plans.

- Definition

The entire disclosure for pension and other postretirement benefits.

+ References+ Details

Stockholders' Equity

12 Months Ended

May 31, 2015

Equity [Abstract]

STOCKHOLDERS' EQUITY

STOCKHOLDERS’ EQUITY

1. Capitalization

On October 29, 2014, our Board of Directors approved our Amended and Restated Certificate of Incorporation (the “Amended Certificate”). Under the Amended Certificate, the authorized capital stock is 80,000,000 shares, consisting of 75,000,000 shares of common stock, par value $.01 per share and 5,000,000 shares of preferred stock, par value $.01 per share.

The holders of common stock are entitled to one vote for each share held. Subject to preferences applicable to any outstanding shares of preferred stock, the holders of common stock are entitled to receive ratably dividends, if any, as may be declared by the Board of Directors out of funds legally available for dividend payments. If we liquidate, dissolve, or wind up, the holders of common stock are entitled to share ratably in all assets remaining after payment of liabilities and liquidation preferences of any outstanding shares of preferred stock. Holders of common stock have no pre-emptive rights or rights to convert their common stock into any other securities. There are no redemption or sinking fund provisions applicable to the common stock. The rights, preferences and privileges of the holders of common stock are subject to, and may be adversely affected by, the rights of the holders of shares of any series of preferred stock that we may designate in the future.

Our board of directors has the authority to (i) issue the undesignated preferred stock in one or more series, (ii) determine the powers, preferences and rights and the qualifications, limitations or restrictions granted to or imposed upon any wholly un-issued series of undesignated preferred stock and (iii) fix the number of shares constituting any series and the designation of the series, without any further vote or action by our stockholders.

Share Repurchase Program

On October 5, 2011, our Board of Directors authorized the repurchase of up to $20 million of our common stock, prior to May 31, 2012. During the fiscal year ended May 31, 2012, we purchased 142,305 shares at a cost of approximately $2.1 million. There were no shares repurchased under this program during fiscal 2015, 2014 or 2013.

2. Stock Options

1997 Stock Option Plan

In 1997, we adopted a Stock Option Plan (the “1997 Plan”). The 1997 Plan provided for the grant to key employees of both nonqualified stock options and incentive stock options and to members of the Board of Directors and consultants of nonqualified stock options. A total of 1,497,674 shares of our common stock were available to be issued under the 1997 Plan pursuant to the exercise of options. All stock options were to have an exercise price of not less than the fair market value of the shares on the date of grant. Options are exercisable over a period of time to be designated by the administrators of the 1997 Plan (but not more than 10 years from the date of grant) and are subject to such other terms and conditions as the administrators may determine. The vesting schedule is subject to the discretion of our Board of Directors. Options are exercisable immediately upon vesting. In addition, all options, whether vested or not, become exercisable in full immediately upon a change of control, as defined under the 1997 Plan. The 1997 Plan terminated in March 2007 and as such, no further options will be granted under this plan.

2004 Stock and Incentive Award Plan

The 2004 Stock and Incentive Award Plan (the “2004 Plan”) provides for the grant of incentive options to our employees and for the grant of non-statutory stock options, restricted stock, stock appreciation rights, performance units, performance shares and other incentive awards to our employees, directors and other service providers. A total of 5,750,000 shares of our common stock have been reserved for issuance under the 2004 Plan, of which up to 800,000 shares may be issued upon the exercise of incentive stock options. The compensation committee of the Board of Directors administers the 2004 Plan. The committee determines vesting terms and the exercise price of options granted under the 2004 Plan, but for all incentive stock options the exercise price must at least be equal to the fair market value of our common stock on the date of grant. The term of an incentive stock option may not exceed ten years. During the year ended May 31, 2015 an additional 1,000,000 shares of our common stock have been reserved for issuance under the 2004 plan.

On October 5, 2011, we amended the 2004 Stock and Incentive Award Plan to increase the maximum number of shares of our common stock with respect to which stock options may be granted during any calendar year to one employee from 200,000 shares to 500,000 shares.

The following table summarizes information about stock options activity for the fiscal year ended May 31, 2015.



	2015
	Shares		Weighted- average exercise price		Weighted average remaining contractual life	Aggregate intrinsic value (in thousands)
Outstanding at beginning of year	2,673,751		$	14.82
Granted	561,883		$	16.14
Exercised	(423,804	)	$	13.87
Forfeited	(261,738	)	$	14.71
Expired	(250,779	)	$	17.98
Outstanding at end of year	2,299,313		$	14.86	3.89	$	4,571
Options exercisable at year-end	1,271,028		$	15.10	2.58	$	2,547
Options expected to vest in future periods	903,143		$	14.56	5.52	$	1,778

As of May 31, 2015, there remained approximately 2.3 million shares available for granting of options under the 2004 Plan. Options are exercisable into common stock.

The following table summarizes information about stock options outstanding at May 31, 2015.



Range of exercise prices	Number outstanding	Weighted- average remaining life in years	Weighted- average exercise price		Number Exercisable	Weighted- average exercise price
$10.25 - $14.24	1,403,859	4.09	$	12.94	793,406	$	13.03
$14.25 - $18.24	564,416	4.13	15.96		251,584	15.51
$18.25 - $22.24	217,069	3.75	19.38		112,069	19.35
$22.25 - $26.24	99,908	0.43	23.94		99,908	23.94
$26.25 - $30.24	14,061	0.94	28.10		14,061	28.10
	2,299,313	3.89	$	14.86	1,271,028	$	15.10

Stock options are granted at exercise prices equal to the quoted market price of our common stock at the date of the grant. Options vest 25% per year over four years for employees and 100% after one year for consultants. Grants to directors vest 33.33% per year over three years. Stock options granted prior to May 1, 2007 expire on the tenth anniversary of the grant date. Stock options granted on or after May 1, 2007, expire on the seventh anniversary of the grant date.

We measure the fair value of each stock option grant at the date of grant using a Black-Scholes option pricing model. The weighted average grant-date fair value of options granted during the years ended 2015, 2014 and 2013 was $4.74, $4.10, and $4.19, respectively. The following assumptions were used in arriving at the fair value of options granted during 2015, 2014 and 2013, respectively: risk-free interest rates of 1.54%, 1.44% and 0.62%; expected volatility of 31%, 34%, and 44%; and expected lives of 4.76 years, 4.74 years, and 4.62 years. We do not declare dividends therefore a dividend yield of zero was used for the years ended 2015, 2014 and 2013. Risk-free interest rates reflect the yield on zero-coupon U.S. Treasury bonds whose maturity period equals the expected term of the option. Expected volatilities are based on the historical volatility of our stock. The expected option lives are based on our historical experience of employee exercise behavior.

The total intrinsic value of options exercised during the years ended 2015, 2014 and 2013 amounted to $1.6 million, $1.0 million, and $0.1 million, respectively. As of May 31, 2015, there was $3.5 million of total unrecognized compensation cost related to non-vested options. The cost is expected to be recognized over a weighted average period of 3 years.

Cash received from option exercises during 2015, 2014 and 2013 was $4.3 million, $1.3 million and $0.1 million, respectively. The tax benefit realized from stock options exercised during the years ended 2015 and 2014 was $0.5 million and $0.1 million, respectively. There was no tax benefit realized from stock option exercises during the year ended 2013.

3. Performance Share and Restricted Stock Unit Awards

We grant restricted stock units to certain employees under the 2004 Plan which give the recipients the right to receive shares of our stock upon vesting. The restricted stock unit awards vest in equal annual installments over the term of the grants. Unvested restricted stock unit awards will be forfeited if the recipient ceases to be employed by us, competes with our business or otherwise engages in activities detrimental to our business before such date.

The following table summarizes information about restricted stock unit activity for the year ended May 31, 2015.



	Non-Vested Stock Award Units		Weighted Average Grant-Date Fair Value
Non-vested at beginning of year	587,991		$	14.82
Granted	242,158		$	14.75
Vested	(160,207	)	$	14.83
Canceled	(106,841	)	$	12.33
Non-vested at end of year	563,101		$	13.73
Awards expected to vest in future periods	492,432		$	13.73

The fair value of each restricted stock unit is the market price of our stock on the date of grant. The weighted average grant date fair value of restricted stock units granted during the years ended 2015, 2014 and 2013 was $14.75, $13.23 and $10.79, respectively. The total intrinsic value of restricted stock units vesting during the years ended 2015, 2014 and 2013 was $2.4 million, $1.8 million, and $1.2 million, respectively. As of May 31, 2015, there was $5.6 million of total unrecognized compensation cost related to non-vested restricted stock awards. The cost is expected to be recognized over a weighted average period of 2 years.

We grant performance share awards to certain employees under the 2004 Plan which gives the recipients the right to receive shares of our stock if certain criteria is met. The performance criteria is established by the compensation committee for vesting of the performance share awards and may include factors such as the achievement of certain sales, operating income and earnings per share (“EPS”) goals. Performance share awards are subject to additional conditions, including the recipient’s continued employment with us.

Performance share units are valued using a Monte Carlo simulation model on the date of grant. As of May 31, 2015 and 2014, the weighted average grant date fair market value for new grants was $19.83 and $25.56, respectively. Compensation cost is recognized over the performance period when the metrics are probable of being achieved which is typically three years. As of May 31, 2015, 0.2 million performance share units with a weighted average remaining contractual term of 3 years and $2.2 million of unrecognized compensation cost were outstanding. As of May 31, 2014, 0.1 million performance share units with a weighted average remaining contractual term of 3 years and $1.8 million of unrecognized compensation cost were outstanding.

4. Employee Stock Purchase Plan

The Employee Stock Purchase Plan (the “Stock Purchase Plan”) provides a means by which our employees (the “participants”) are given an opportunity to purchase our common stock through payroll deductions. On October 29, 2014, our Board of Directors, approved our Amended and Restated Certificate of Incorporation (the “Amended Certificate”). Under the Amended Certificate, the maximum number of shares to be offered under the Stock Purchase Plan is 2,000,000 shares of our common stock, subject to any increase authorized by the Board of Directors. Shares are offered through two purchase periods, each with duration of approximately 6 months, commencing on the first business day of the first and third fiscal quarters. An employee is eligible to participate in an offering period if, on the first day of an offering period, he or she has been employed in a full-time capacity for at least six months, with a customary working schedule of 20 or more hours per week and more than five months in a calendar year. Employees who own stock possessing 5% or more of the total combined voting power or value of all classes of our stock are not eligible to participate in the Stock Purchase Plan. The purchase price of the shares of common stock acquired on each purchase date will be the lower of (i) 85% of the fair market value of a share of common stock on the first day of the offering period or (ii) 85% of the fair market value of a share of common stock on the last day of the purchase period, subject to adjustments made by the Board of Directors. The Stock Purchase Plan is intended to qualify as an “employee stock purchase plan” within the meaning of Section 423 of the Internal Revenue Code. During the year ended May 31, 2015, an additional 800,000 shares of our common stock have been reserved for issuance under the Stock Purchase Plan.

We use the Black-Scholes option-pricing model to calculate the purchase date fair value of the shares issued under the Stock Purchase Plan and recognize expense related to shares purchased ratably over the offering period. During the years ended 2015, 2014 and 2013, 119,001, 146,275 and 123,556 shares, respectively, were issued at an average price of $11.89, $9.30 and $9.80, respectively, under the Stock Purchase Plan. As of May 31, 2015, 1.1 million shares remained available for future purchases under the Stock Purchase Plan.

5. Other items

Share-based compensation expense recognized in the consolidated statement of operations during the years ended 2015, 2014 and 2013 amounted to $6.0 million, $5.5 million and $4.6 million, respectively. The income tax benefit recognized in earnings on the compensation expense recognized for all share-based compensation arrangements amounted to $2.0 million, $1.8 million and $1.5 million, respectively. Income tax expense of $1.3 million and $0.5 million was recorded in continuing operations for the excess of cumulative book deductions over actual tax deductions for the years ended 2015 and 2014, respectively. Additional income tax expense of $0.1 million for 2014 and $1.6 million for 2013 was recorded in shareholder’s equity for the excess book deductions to the extent prior tax deductions exceeded prior book deductions.

- Definition

The entire disclosure for shareholders' equity comprised of portions attributable to the parent entity and noncontrolling interest, including other comprehensive income. Includes, but is not limited to, balances of common stock, preferred stock, additional paid-in capital, other capital and retained earnings, accumulated balance for each classification of other comprehensive income and amount of comprehensive income.

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+ Details

Earnings Per Share (Notes)

12 Months Ended

May 31, 2015

Earnings Per Share [Abstract]

Earnings Per Share

EARNINGS PER SHARE

Basic earnings per share are based on the weighted average number of common shares outstanding without consideration of potential common stock. In addition, diluted earnings per share include the dilutive effect of potential common stock consisting of stock options, restricted stock units and performance stock units, provided that the inclusion of such securities is not anti-dilutive. In periods with a net loss, stock options and restricted stock units are not included in the computation of basic loss per share as the impact would be anti-dilutive.

The following table reconciles basic to diluted weighted average shares outstanding for the years ended May 31, 2015, 2014 and 2013:



	2015	2014	2013
Basic	35,683,139	35,135,689	34,817,279
Effect of dilutive securities	—	304,161	—
Diluted	35,683,139	35,439,850	34,817,279

Securities excluded as their inclusion would be anti-dilutive	2,862,414	2,347,426	2,904,944

- Definition

The entire disclosure for earnings per share.

+ References+ Details

Commitments and Contingencies

12 Months Ended

May 31, 2015

Commitments and Contingencies Disclosure [Abstract]

COMMITMENTS AND CONTINGENCIES

Leases

We are committed under non-cancelable operating leases for facilities and equipment. During fiscal 2015, 2014 and 2013, aggregate rental costs under all operating leases were approximately $3.4 million, $2.0 million and $2.5 million, respectively. Future annual payments under non-cancelable operating leases in the aggregate, of which one includes an escalation clause, with initial remaining terms of more than one year at May 31, 2015, are summarized as follows (in thousands):



2016	$	2,192
2017	2,013
2018	1,980
2019	1,962
2020	1,749
	$	9,896

Litigation Matters

AngioDynamics v. biolitec

On January 2, 2008, we commenced an action in the United States District Court for the Northern District of New York entitled AngioDynamics, Inc. v. biolitec, Inc. In this action, we sought judgment against biolitec for defense and indemnification in two lawsuits which we previously settled. Our claims arise out of a Supply and Distribution Agreement (“SDA”) entered into with biolitec on April 1, 2002. On September 27, 2011, the U.S. District Court granted key portions of our motion for summary judgment in our legal case against biolitec. The Court also dismissed biolitec’s counterclaims against us. The court denied one portion of our summary judgment motion, which sought to recover additional costs from biolitec, leaving this for adjudication at trial. On November 8, 2012, the Court granted partial judgment to us in the amount of $23.2 million. Biolitec appealed this judgment. On August 23, 2013, the U.S. Court of Appeals for the Second Circuit dismissed biolitec’s appeal.

In October 2009, we commenced an action in the United States District Court for the District of Massachusetts entitled AngioDynamics, Inc. v. biolitec AG and Wolfgang Neuberger. The Complaint in this action was amended in March 2010. This action seeks to recover against biolitec, Inc.’s parent entities and CEO for tortiously interfering with biolitec, Inc.’s contractual obligation to defend and indemnify us, and also seeks to pierce the corporate veil of biolitec, Inc. and to invalidate certain alleged fraudulent transfers in order to hold biolitec, Inc.’s parent entities jointly and severally liable for the alleged breach of the SDA. On September 13, 2012, the Massachusetts Court granted our request for a preliminary injunction prohibiting the downstream merger of biolitec AG with its Austrian subsidiary. On April 1, 2013, the U.S. Court of Appeals for the First Circuit affirmed the preliminary injunction. On January 14, 2014, the District Court entered judgment in our favor as to liability. On March 18, 2014, the District Court entered judgment in our favor against Biolitec AG, Biomed Technology Holdings, Ltd., and Wolfgang Neuberger, jointly and severally, in the amount of $74.9 million. The defendants have appealed this judgment.

August 29, 2013, we became co-plaintiffs in an adversary proceeding in the United States Bankruptcy Court for the District of New Jersey entitled Cyganowski, Trustee, et al. v. Biolitec U.S., Inc., et al. In this action, we assert claims of conversion, unjust enrichment, tortious interference, and unfair competition against various biolitec entities for alleged violation of Bankruptcy Court settlement and sale orders under which we acquired certain assets of Biolitec, Inc. On September 3, 2013, we, along with our co-plaintiff, obtained a temporary restraining order against the defendants in this action. On January 22, 2015, the Bankruptcy Court entered a permanent injunction on our behalf for an additional two years.

C.R. Bard, Inc. v. AngioDynamics, Inc.

On January 11, 2012, C.R. Bard, Inc. filed a suit in the United States District Court of Utah claiming certain of our implantable port products infringe on three U.S. patents held by Bard (the "Utah Action"). Bard is seeking unspecified damages and other relief. The Court denied Bard’s motion for pre-trial consolidation with separate actions it filed on the same day against Medical Components, Inc. and Smiths Medical ASD, Inc., but had asked for supplemental briefing on the issue of whether to conduct a common Markman hearing. Meanwhile, we filed petitions for reexamination in the US Patent and Trademark Office ("PTO") which seek to invalidate all 3 patents asserted in the litigation. Our petitions have been granted and 40 of 41 patent claims have been and remain rejected. The Patent Office has issued a Final Rejection of all the claims subject to reexamination and Bard has filed appeals. The parties have completed briefing on the appeals and oral argument was held on June 18, 2015. The parties are awaiting decision by the Board of Appeals and Interferences. The case has been stayed pending final resolution of the PTO process. The Company believes these claims are without merit and intends to defend them vigorously. The Company has not recorded an expense related to the outcome of this litigation because it is not yet possible to determine if a potential loss is probable nor reasonably estimable.

On March 10, 2015, C.R. Bard, Inc. and Bard Peripheral Vascular, Inc. filed suit in the United States District Court for the District of Delaware claiming certain of the Company’s implantable port products infringe three Bard patents (the “Delaware Action). Bard is seeking unspecified damages and other relief; and the patents asserted in the Delaware Action are different than those asserted in the Utah Action. On June 1,2015, the Company filed two motions in response to Bard’s Complaint - - one seeks transfer to the District of Utah where the Utah Action is currently pending, and the other seeks dismissal of the entire complaint on grounds that none of the claims in the asserted patents is directed to patent eligible subject matter under Section 101 of the Patent Statute and in light of recent authority from the U. S. Supreme Court. Briefing is complete on both motions (except Bard has requested permission to file a Sur-Reply on the dismissal motion) and the parties are awaiting decision by the Delaware Court. The Company believes these claims are without merit and intends to defend them vigorously. The Company has not recorded an expense related to the outcome of this litigation because it is not yet possible to determine if a potential loss is probable nor reasonably estimable.

Governmental Investigations

LC Beads

In June 2014 we received a subpoena from the U.S. Department of Justice (the “DOJ”) requesting documents in relation to a purported criminal investigation the DOJ is conducting regarding BTG International, Inc.’s LC Bead^® product beginning in 2003. RITA Medical Systems and AngioDynamics, Inc., after its acquisition of RITA, was the exclusive distributor of LC Beads in the United States from 2006 through December 31, 2011. We are cooperating fully with this investigation and at this time are unable to predict its scope, duration or outcome.

EVLT

In April 2015 we received a subpoena from the DOJ requesting documents in relation to a criminal investigation the DOJ is conducting regarding purported marketing and sale of certain of AngioDynamics’ VenaCure EVLT products for the treatment of certain indications that had not been approved by the FDA. We are cooperating fully with this investigation and at this time are unable to predict its scope, duration or outcome.

Future Purchase Obligations

We have entered into commitments for future minimum inventory purchases related to several core products. Total future non-cancelable purchase obligations through fiscal 2018 amount to $9.9 million. There are no such obligations thereafter.

- Definition

The entire disclosure for commitments and contingencies.

+ References+ Details

Segments and Geographic Information

12 Months Ended

May 31, 2015

Segment Reporting [Abstract]

SEGMENTS AND GEOGRAPHIC INFORMATION

Segment information

We consider our business to be a single segment entity related to the development, manufacture and sale on a global basis of medical devices for vascular access, surgery, peripheral vascular disease and oncology. Our chief operating decision maker (CEO) evaluates the various global product portfolios on a net sales basis. Executives reporting in to the CEO include those responsible for operations and supply chain management, research and development, sales, franchise marketing and certain corporate functions. The CEO evaluates profitability, investment and cash flow metrics on a consolidated worldwide basis due to shared infrastructure and resources. Prior to fiscal year 2013, our business was organized as two segments: Vascular and Oncology/Surgery, each under the direction of a general manager with direct responsibility for all sales, marketing and product development activities.

Total sales by product category are summarized below (in thousands):



	Year Ended
	May 31, 2015		May 31, 2014		May 31, 2013
Net sales by Product Category
Peripheral Vascular	$	192,833	$	192,626	$	179,573
Vascular Access	107,874		106,394		106,690
Oncology/Surgery	52,090		49,360		47,155
Supply Agreement	4,177		6,045		8,498
Total	$	356,974	$	354,425	$	341,916

Geographic information

Total sales for geographic areas are summarized below (in thousands):



	Year Ended
	May 31, 2015		May 31, 2014		May 31, 2013
Net sales by Geography
United States	$	280,851	$	280,161	$	266,228
International	71,946		68,219		67,190
Supply Agreement	4,177		6,045		8,498
Total	$	356,974	$	354,425	$	341,916

For fiscal years 2015, 2014 and 2013, International sales as a percentage of total net sales were 20%, 19% and 20%, respectively. Sales to any one country outside the U.S., as determined by shipment destination, did not comprise a material portion of our net sales in any of the last three fiscal years. 99% of our total assets are located within the United States.

- Definition

The entire disclosure for reporting segments including data and tables. Reportable segments include those that meet any of the following quantitative thresholds a) it's reported revenue, including sales to external customers and intersegment sales or transfers is 10 percent or more of the combined revenue, internal and external, of all operating segments b) the absolute amount of its reported profit or loss is 10 percent or more of the greater, in absolute amount of 1) the combined reported profit of all operating segments that did not report a loss or 2) the combined reported loss of all operating segments that did report a loss c) its assets are 10 percent or more of the combined assets of all operating segments.

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+ Details

Restructuring	12 Months Ended
Restructuring	May 31, 2015
Restructuring and Related Activities [Abstract]
RESTRUCTURING	RESTRUCTURING On December 5, 2013, we announced a company-wide operational excellence program designed to save between $15 and $18 million during the course of the next three years. The initiative is expected to create greater efficiencies and drive business performance improvements by focusing on several key elements, including product rationalization, lean manufacturing initiatives, supply chain optimization and enterprise resource planning (ERP) implementation. The plan also incorporates the consolidation of our New York plants to establish a single manufacturing center in Glens Falls and a distribution center in Queensbury. During the course of the three-year program, it is expected that we will reduce our New York employee base by approximately 80-100 positions as a result of this plant consolidation and reorganization. Over the three year period, we expect to invest $5.4 million in facility improvements. In addition, total restructuring charges are estimated to be $4.7 million. During the year end May 31, 2015, the cost incurred was $2.0 million, consisting of $1.5 million of accelerated depreciation and $0.5 million of severance and related costs. During the year ended May 31, 2014, the cost incurred was $1.4 million, consisting of $0.6 million of severance and related costs, $0.7 million of accelerated depreciation and $0.1 million in other costs. These costs are included in “Acquisition, restructuring and other items, net” in the statements of income. During the year ended May 31, 2015, we initiated a restructuring of finance, R&D and S&M organizations to improve our profitability. As part of the restructuring, we recorded $0.8 million in severance expense which is included in "Acquisition, restructuring and other items, net" in the statement of operations.

- Definition

The entire disclosure for restructuring and related activities. Description of restructuring activities such as exit and disposal activities, include facts and circumstances leading to the plan, the expected plan completion date, the major types of costs associated with the plan activities, total expected costs, the accrual balance at the end of the period, and the periods over which the remaining accrual will be settled.

+ References+ Details

Valuation and Qualifying Accounts

12 Months Ended

May 31, 2015

Valuation and Qualifying Accounts [Abstract]

VALUATION AND QUALIFYING ACCOUNTS

AngioDynamics, Inc. and Subsidiaries



	SCHEDULE II -VALUATION AND QUALIFYING ACCOUNTS
	(in thousands)
Column A	Column B		Column C		Column D			Column E
Description	Balance at Beginning of Year		Additions - Charged to costs and expenses		Deductions			Balance at End of Period
Year Ended May 31, 2013
Allowance for deferred tax asset (a)	1,196		—		(484		)	712
Allowance for sales returns and doubtful accounts (b)	933		4,134		(3,795		)	1,272
Totals	$	2,129	$	4,134	$	(4,279	)	$	1,984
Year Ended May 31, 2014
Allowance for deferred tax asset (a)	712		819		—			1,531
Allowance for sales returns and doubtful accounts (b)	1,272		7,342		(6,878		)	1,736
Totals	$	1,984	$	8,161	$	(6,878	)	$	3,267
Year Ended May 31, 2015
Allowance for deferred tax asset (a)	1,531		467		(207		)	1,791
Allowance for sales returns and doubtful accounts (b)	1,736		1,846		(539		)	3,043
Totals	$	3,267	$	2,313	$	(746	)	$	4,834


(a)	Use of fully reserved capital losses and expiration of fully reserved state tax credits.


(b)	Previously reserved sales returns and accounts written off as uncollectible.

Basis of Presentation, Business Description and Summary of Significant Accounting Policies (Policies)

12 Months Ended

May 31, 2015

Accounting Policies [Abstract]

Basis of Presentation and Description of Business

Cash and Cash Equivalents

Marketable Securities

Accounts Receivable

Inventories

Property, Plant and Equipment



		Estimated useful lives
Building and building improvements		39 years
Machinery and equipment		3 to 8 years
Computer software and equipment		3 to 10 years

Goodwill and Intangible Assets

Revenue Recognition

Research and Development

Income Taxes

We do not anticipate that the amount of unrecognized tax benefits will significantly change in the next twelve months.

Fair Value of Financial Instruments



Level 1	Quoted prices in active markets for identical assets or liabilities. Level 1 assets include money market funds that are traded in an active exchange market.



Level 2	Observable inputs other than Level 1 prices such as quoted prices for similar assets or liabilities; quoted prices in markets that are not active; or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities. When quoted market prices are unobservable, we obtain pricing information from an independent pricing vendor. The pricing vendor uses various pricing models for each asset class that are consistent with what other market participants would use. The inputs and assumptions to the model of the pricing vendor are derived from market observable sources including: benchmark yields, reported trades, broker/dealer quotes, issuer spreads, benchmark securities, bids, offers, and other market-related data. The pricing vendor considers all available market observable inputs in determining the evaluation for a security. Thus, certain securities may not be priced using quoted prices, but rather determined from market observable information. Included in Level 2 assets is our interest rate swap agreement which is valued using a mid-market valuation model.



Level 3	Unobservable inputs that are supported by little or no market activity and are significant to the fair value of the assets or liabilities. Level 3 assets and liabilities include financial instruments whose value is determined using pricing models, discounted cash flow methodologies, or similar techniques, as well as instruments for which the determination of fair value requires significant management judgment or estimation. This category includes the auction rate securities where independent pricing information was not able to be obtained and the contingent considerations related to the acquisition of Vortex, Microsulis and Clinical Devices. Our investments in auction-rate securities were classified as Level 3 as quoted prices were unavailable since these auction rate securities issued by New York state and local government authorities failed auction. Due to limited market information, we utilized a discounted cash flow (“DCF”) model to derive an estimate of fair value for contingent considerations for all periods presented. The assumptions used in preparing the DCF model included estimates with respect to the amount and timing of future interest and principal payments, forward projections of the interest rate benchmarks, the probability of full repayment of the principal considering the credit quality and guarantees in place, and the rate of return required by investors to own such securities given the current liquidity risk associated with auction-rate securities.

The following tables provide information by level for assets and liabilities that are measured at fair value (in thousands):



	Fair Value Measurements using inputs considered as:
	Level 1		Level 2		Level 3		Fair Value at May 31, 2015
Financial Assets
Marketable securities
New York State government agency obligations	$	—	$	—	$	1,689	$	1,689
Total	—		—		1,689		1,689
Total Financial Assets	$	—	$	—	$	1,689	$	1,689
Financial Liabilities
Interest rate swap agreements	$	—	$	257	$	—	$	257
Contingent liability for acquisition earn out	—		—		47,384		47,384
Total Financial Liabilities	$	—	$	257	$	47,384	$	47,641



	Fair Value Measurements using inputs considered as:
	Level 1		Level 2		Level 3		Fair Value at May 31, 2014
Financial Assets
Cash equivalents
Money market funds	$	445	$	—	$	—	$	445
Total	445		—		—		445
Marketable securities
New York State government agency obligations	—		—		1,809		1,809
Total	—		—		1,809		1,809
Total Financial Assets	$	445	$	—	$	1,809	$	2,254
Financial Liabilities
Interest rate swap agreements	$	—	$	555	$	—	$	555
Contingent liability for acquisition earn out	—		—		67,331		67,331
Total Financial Liabilities	$	—	$	555	$	67,331	$	67,886

There were no transfers in and out of Level 1, 2 and 3 measurements for the years ended May 31, 2015 and 2014.

The components of Level 3 fair value instruments as of May 31, 2015 are shown below (in thousands):



	Financial Assets			Financial Liabilities
	Fair Value Measurements Using Significant Unobservable Inputs (Level 3)			Fair Value Measurements Using Significant Unobservable Inputs
Balance at May 31, 2014	$	1,809		$	67,331
Change in fair value of contingent consideration (1)	—			(8,196		)
Currency (gain) loss from remeasurement	—			(529		)
Included in other comprehensive income (loss)	(120		)	—
Contingent consideration payments	—			(11,222		)
Balance at May 31, 2015	$	1,689		$	47,384

The components of Level 3 fair value instruments as of May 31, 2014 are shown below (in thousands):



	Financial Assets			Financial Liabilities
	Fair Value Measurements Using Significant Unobservable Inputs (Level 3)			Fair Value Measurements Using Significant Unobservable Inputs
Balance at May 31, 2013	$	1,850		$	75,049
Change in fair value of contingent consideration (1)	—			(1,808		)
New contingent consideration	—			4,970
Currency (gain) loss from remeasurement	—			—
Included in other comprehensive income (loss)	(41		)	—
Contingent consideration payments	—			(10,880		)
Balance at May 31, 2014	$	1,809		$	67,331

Contingent Liability for Acquisition Earn Outs

The recurring Level 3 fair value measurements of the contingent consideration liabilities include the following significant unobservable inputs as of May 31, 2015 (in thousands of dollars):



	Fair value at May 31, 2015		Valuation Technique	Unobservable Input	Range
Revenue based payments	$	44,716	Discounted cash flow	Discount rate Probability of payment Projected fiscal year of payment	4% 75% - 100% 2016 - 2022
Milestone based payments	2,668		Discounted cash flow	Discount rate Probability of payment Projected fiscal year of payment	16% 75% - 100% 2017
	$	47,384

Derivative Financial Instruments

Supplier Concentrations

Basis of Presentation, Business Description and Summary of Significant Accounting Policies (Tables)

12 Months Ended

May 31, 2015

Accounting Policies [Abstract]

Fair value of assets and liabilities measured on recurring basis

The following tables provide information by level for assets and liabilities that are measured at fair value (in thousands):



	Fair Value Measurements using inputs considered as:
	Level 1		Level 2		Level 3		Fair Value at May 31, 2015
Financial Assets
Marketable securities
New York State government agency obligations	$	—	$	—	$	1,689	$	1,689
Total	—		—		1,689		1,689
Total Financial Assets	$	—	$	—	$	1,689	$	1,689
Financial Liabilities
Interest rate swap agreements	$	—	$	257	$	—	$	257
Contingent liability for acquisition earn out	—		—		47,384		47,384
Total Financial Liabilities	$	—	$	257	$	47,384	$	47,641



	Fair Value Measurements using inputs considered as:
	Level 1		Level 2		Level 3		Fair Value at May 31, 2014
Financial Assets
Cash equivalents
Money market funds	$	445	$	—	$	—	$	445
Total	445		—		—		445
Marketable securities
New York State government agency obligations	—		—		1,809		1,809
Total	—		—		1,809		1,809
Total Financial Assets	$	445	$	—	$	1,809	$	2,254
Financial Liabilities
Interest rate swap agreements	$	—	$	555	$	—	$	555
Contingent liability for acquisition earn out	—		—		67,331		67,331
Total Financial Liabilities	$	—	$	555	$	67,331	$	67,886

Fair value measurements using significant unobservable inputs

The components of Level 3 fair value instruments as of May 31, 2015 are shown below (in thousands):



	Financial Assets			Financial Liabilities
	Fair Value Measurements Using Significant Unobservable Inputs (Level 3)			Fair Value Measurements Using Significant Unobservable Inputs
Balance at May 31, 2014	$	1,809		$	67,331
Change in fair value of contingent consideration (1)	—			(8,196		)
Currency (gain) loss from remeasurement	—			(529		)
Included in other comprehensive income (loss)	(120		)	—
Contingent consideration payments	—			(11,222		)
Balance at May 31, 2015	$	1,689		$	47,384

Summary showing the recurring fair value measurements of the contingent consideration liability

The recurring Level 3 fair value measurements of the contingent consideration liabilities include the following significant unobservable inputs as of May 31, 2015 (in thousands of dollars):



	Fair value at May 31, 2015		Valuation Technique	Unobservable Input	Range
Revenue based payments	$	44,716	Discounted cash flow	Discount rate Probability of payment Projected fiscal year of payment	4% 75% - 100% 2016 - 2022
Milestone based payments	2,668		Discounted cash flow	Discount rate Probability of payment Projected fiscal year of payment	16% 75% - 100% 2017
	$	47,384

Reconciliation of the weighted-average number of common shares

The following table reconciles basic to diluted weighted average shares outstanding for the years ended May 31, 2015, 2014 and 2013:



	2015	2014	2013
Basic	35,683,139	35,135,689	34,817,279
Effect of dilutive securities	—	304,161	—
Diluted	35,683,139	35,439,850	34,817,279

Securities excluded as their inclusion would be anti-dilutive	2,862,414	2,347,426	2,904,944

- Definition

Tabular disclosure of liabilities, including [financial] instruments measured at fair value that are classified in stockholders' equity, if any, by class that are measured at fair value on a recurring basis. The disclosures contemplated herein include the fair value measurements at the reporting date by the level within the fair value hierarchy in which the fair value measurements in their entirety fall, segregating fair value measurements using quoted prices in active markets for identical assets (Level 1), significant other observable inputs (Level 2), and significant unobservable inputs (Level 3). Where the quoted price in an active market for the identical liability is not available, the Level 1 input is the quoted price of an identical liability when traded as an asset.

+ References+ Details

- Definition

Tabular disclosure of the fair value measurement of liabilities using significant unobservable inputs (Level 3), a reconciliation of the beginning and ending balances, separately presenting changes attributable to the following: (1) total gains or losses for the period (realized and unrealized), segregating those gains or losses included in earnings (or changes in net assets), and gains or losses recognized in other comprehensive income (loss) and a description of where those gains or losses included in earnings (or changes in net assets) are reported in the statement of income (or activities); (2) purchases, sales, issues, and settlements (each type disclosed separately); and (3) transfers in and transfers out of Level 3 (for example, transfers due to changes in the observability of significant inputs) by class of liability.

+ References+ Details

Fair Value of Financial Instruments Fair Value of Financial Instruments (Tables)

12 Months Ended

May 31, 2015

Fair Value Disclosures [Abstract]

Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block]

The following tables provide information by level for assets and liabilities that are measured at fair value (in thousands):



	Fair Value Measurements using inputs considered as:
	Level 1		Level 2		Level 3		Fair Value at May 31, 2015
Financial Assets
Marketable securities
New York State government agency obligations	$	—	$	—	$	1,689	$	1,689
Total	—		—		1,689		1,689
Total Financial Assets	$	—	$	—	$	1,689	$	1,689
Financial Liabilities
Interest rate swap agreements	$	—	$	257	$	—	$	257
Contingent liability for acquisition earn out	—		—		47,384		47,384
Total Financial Liabilities	$	—	$	257	$	47,384	$	47,641



	Fair Value Measurements using inputs considered as:
	Level 1		Level 2		Level 3		Fair Value at May 31, 2014
Financial Assets
Cash equivalents
Money market funds	$	445	$	—	$	—	$	445
Total	445		—		—		445
Marketable securities
New York State government agency obligations	—		—		1,809		1,809
Total	—		—		1,809		1,809
Total Financial Assets	$	445	$	—	$	1,809	$	2,254
Financial Liabilities
Interest rate swap agreements	$	—	$	555	$	—	$	555
Contingent liability for acquisition earn out	—		—		67,331		67,331
Total Financial Liabilities	$	—	$	555	$	67,331	$	67,886

Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block]

The components of Level 3 fair value instruments as of May 31, 2015 are shown below (in thousands):



	Financial Assets			Financial Liabilities
	Fair Value Measurements Using Significant Unobservable Inputs (Level 3)			Fair Value Measurements Using Significant Unobservable Inputs
Balance at May 31, 2014	$	1,809		$	67,331
Change in fair value of contingent consideration (1)	—			(8,196		)
Currency (gain) loss from remeasurement	—			(529		)
Included in other comprehensive income (loss)	(120		)	—
Contingent consideration payments	—			(11,222		)
Balance at May 31, 2015	$	1,689		$	47,384

Fair Value, Liabilities Measured on Recurring Basis [Table Text Block]

The recurring Level 3 fair value measurements of the contingent consideration liabilities include the following significant unobservable inputs as of May 31, 2015 (in thousands of dollars):



	Fair value at May 31, 2015		Valuation Technique	Unobservable Input	Range
Revenue based payments	$	44,716	Discounted cash flow	Discount rate Probability of payment Projected fiscal year of payment	4% 75% - 100% 2016 - 2022
Milestone based payments	2,668		Discounted cash flow	Discount rate Probability of payment Projected fiscal year of payment	16% 75% - 100% 2017
	$	47,384

Organization, Consolidation and Presentation of Financial Statements Disclosure and Significant Accounting Policies [Text Block]

BASIS OF PRESENTATION, BUSINESS DESCRIPTION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

1. Basis of Presentation and Description of Business

All intercompany balances and transactions have been eliminated.

Cash and Cash Equivalents

Marketable Securities

Accounts Receivable

Inventories

Property, Plant and Equipment



		Estimated useful lives
Building and building improvements		39 years
Machinery and equipment		3 to 8 years
Computer software and equipment		3 to 10 years

Goodwill and Intangible Assets

Revenue Recognition

Research and Development

Income Taxes

We do not anticipate that the amount of unrecognized tax benefits will significantly change in the next twelve months.

Derivative Financial Instruments

Supplier Concentrations

Reclassification

Certain prior period disclosures have been reclassified to conform to current year presentation. These reclassifications are considered immaterial.

Recent Events

Regulatory Matters

Recently Issued Accounting Pronouncements



Level 1	Quoted prices in active markets for identical assets or liabilities. Level 1 assets include money market funds that are traded in an active exchange market.



Level 2	Observable inputs other than Level 1 prices such as quoted prices for similar assets or liabilities; quoted prices in markets that are not active; or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities. When quoted market prices are unobservable, we obtain pricing information from an independent pricing vendor. The pricing vendor uses various pricing models for each asset class that are consistent with what other market participants would use. The inputs and assumptions to the model of the pricing vendor are derived from market observable sources including: benchmark yields, reported trades, broker/dealer quotes, issuer spreads, benchmark securities, bids, offers, and other market-related data. The pricing vendor considers all available market observable inputs in determining the evaluation for a security. Thus, certain securities may not be priced using quoted prices, but rather determined from market observable information. Included in Level 2 assets is our interest rate swap agreement which is valued using a mid-market valuation model.



Level 3	Unobservable inputs that are supported by little or no market activity and are significant to the fair value of the assets or liabilities. Level 3 assets and liabilities include financial instruments whose value is determined using pricing models, discounted cash flow methodologies, or similar techniques, as well as instruments for which the determination of fair value requires significant management judgment or estimation. This category includes the auction rate securities where independent pricing information was not able to be obtained and the contingent considerations related to the acquisition of Vortex, Microsulis and Clinical Devices. Our investments in auction-rate securities were classified as Level 3 as quoted prices were unavailable since these auction rate securities issued by New York state and local government authorities failed auction. Due to limited market information, we utilized a discounted cash flow (“DCF”) model to derive an estimate of fair value for contingent considerations for all periods presented. The assumptions used in preparing the DCF model included estimates with respect to the amount and timing of future interest and principal payments, forward projections of the interest rate benchmarks, the probability of full repayment of the principal considering the credit quality and guarantees in place, and the rate of return required by investors to own such securities given the current liquidity risk associated with auction-rate securities.

The following tables provide information by level for assets and liabilities that are measured at fair value (in thousands):



	Fair Value Measurements using inputs considered as:
	Level 1		Level 2		Level 3		Fair Value at May 31, 2015
Financial Assets
Marketable securities
New York State government agency obligations	$	—	$	—	$	1,689	$	1,689
Total	—		—		1,689		1,689
Total Financial Assets	$	—	$	—	$	1,689	$	1,689
Financial Liabilities
Interest rate swap agreements	$	—	$	257	$	—	$	257
Contingent liability for acquisition earn out	—		—		47,384		47,384
Total Financial Liabilities	$	—	$	257	$	47,384	$	47,641



	Fair Value Measurements using inputs considered as:
	Level 1		Level 2		Level 3		Fair Value at May 31, 2014
Financial Assets
Cash equivalents
Money market funds	$	445	$	—	$	—	$	445
Total	445		—		—		445
Marketable securities
New York State government agency obligations	—		—		1,809		1,809
Total	—		—		1,809		1,809
Total Financial Assets	$	445	$	—	$	1,809	$	2,254
Financial Liabilities
Interest rate swap agreements	$	—	$	555	$	—	$	555
Contingent liability for acquisition earn out	—		—		67,331		67,331
Total Financial Liabilities	$	—	$	555	$	67,331	$	67,886

There were no transfers in and out of Level 1, 2 and 3 measurements for the years ended May 31, 2015 and 2014.

The components of Level 3 fair value instruments as of May 31, 2015 are shown below (in thousands):



	Financial Assets			Financial Liabilities
	Fair Value Measurements Using Significant Unobservable Inputs (Level 3)			Fair Value Measurements Using Significant Unobservable Inputs
Balance at May 31, 2014	$	1,809		$	67,331
Change in fair value of contingent consideration (1)	—			(8,196		)
Currency (gain) loss from remeasurement	—			(529		)
Included in other comprehensive income (loss)	(120		)	—
Contingent consideration payments	—			(11,222		)
Balance at May 31, 2015	$	1,689		$	47,384

The components of Level 3 fair value instruments as of May 31, 2014 are shown below (in thousands):



	Financial Assets			Financial Liabilities
	Fair Value Measurements Using Significant Unobservable Inputs (Level 3)			Fair Value Measurements Using Significant Unobservable Inputs
Balance at May 31, 2013	$	1,850		$	75,049
Change in fair value of contingent consideration (1)	—			(1,808		)
New contingent consideration	—			4,970
Currency (gain) loss from remeasurement	—			—
Included in other comprehensive income (loss)	(41		)	—
Contingent consideration payments	—			(10,880		)
Balance at May 31, 2014	$	1,809		$	67,331

Contingent Liability for Acquisition Earn Outs

The recurring Level 3 fair value measurements of the contingent consideration liabilities include the following significant unobservable inputs as of May 31, 2015 (in thousands of dollars):



	Fair value at May 31, 2015		Valuation Technique	Unobservable Input	Range
Revenue based payments	$	44,716	Discounted cash flow	Discount rate Probability of payment Projected fiscal year of payment	4% 75% - 100% 2016 - 2022
Milestone based payments	2,668		Discounted cash flow	Discount rate Probability of payment Projected fiscal year of payment	16% 75% - 100% 2017
	$	47,384

- Definition

+ References+ Details

- Definition

+ References+ Details

- Definition

+ References+ Details

Marketable Securities and Investments (Tables)

12 Months Ended

May 31, 2015

Investments, Debt and Equity Securities [Abstract]

Marketable securities

As of May 31, 2015, marketable securities consisted of the following:



	Amortized cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
	(in thousands)
Available-for-sales securities
New York State government agency obligations	$	1,825	$	—	$	(136	)	$	1,689
	$	1,825	$	—	$	(136	)	$	1,689

As of May 31, 2014, marketable securities consisted of the following:



	Amortized cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
	(in thousands)
Available-for-sales securities
New York State government agency obligations	$	1,825	$	—	$	(16	)	$	1,809
	$	1,825	$	—	$	(16	)	$	1,809

Amortized cost and fair value of marketable securities by contractual maturity



	Amortized cost		Fair Value
	(in thousands)
As of May 31, 2015:
Due in one year or less	$	—	$	—
Due after one through five years	—		—
Due after five through twenty years	1,825		1,689
	$	1,825	$	1,689

Property, Plant and Equipment, at Cost (Tables)

12 Months Ended

May 31, 2015

Property, Plant and Equipment [Abstract]

Property, plant and equipment

Property, plant and equipment are summarized as follows:



	May 31, 2015			May 31, 2014
	(in thousands)
Building and building improvements	$	33,853		$	33,126
Machinery and equipment	23,626			31,880
Computer software and equipment	24,431			25,836
Construction in progress	7,143			12,564
	89,053			103,406
Less accumulated depreciation and amortization	(36,197		)	(37,845		)
	52,856			65,561
Land and land improvements	1,704			1,029
	$	54,560		$	66,590

Goodwill and Intangible Assets (Tables)

12 Months Ended

May 31, 2015

Goodwill and Intangible Assets Disclosure [Abstract]

Intangible assets

As of May 31, 2015 and 2014, intangible assets consisted of the following:



	May 31, 2015
	Gross carrying value		Accumulated amortization			Net carrying value		Weighted average useful life
	(in thousands)							(years)
Product technologies	$	148,776	$	(41,447	)	$	107,329	10.2
Customer relationships	86,371		(42,813		)	43,558		12.0
Trademarks	28,545		(3,229		)	25,316		10.7
In process R&D Acquired	3,600		—			3,600		Indefinite
Licenses	7,913		(5,910		)	2,003		8.3
Distributor relationships	900		(900		)	—		3.0
	$	276,105	$	(94,299	)	$	181,806



	May 31, 2014
	Gross carrying value		Accumulated amortization			Net carrying value		Weighted avg useful life
	(in thousands)							(years)
Product technologies	$	150,298	$	(32,930	)	$	117,368	10.2
Customer relationships	86,645		(37,848		)	48,797		11.9
Trademark—NAMIC	28,600		—			28,600		Indefinite
In process R&D Acquired	3,600		—			3,600		Indefinite
Licenses	7,639		(5,211		)	2,428		8.4
Trademarks	6,345		(1,882		)	4,463		8.0
Distributor relationships	900		(900		)	—		3.0
	$	284,027	$	(78,771	)	$	205,256

Expected amortization expense

Annual amortization of these intangible assets is expected to approximate the following amounts for each of the next five fiscal years (in thousands):



2016	$	18,452
2017	$	18,568
2018	$	19,388
2019	$	21,499
2020	$	22,741

Adjustments to goodwill

Adjustments to goodwill for the fiscal year ended May 31, 2015 and May 31, 2014 are as follows (in thousands):



	Total
Balance, May 31, 2013	$	355,637
Acquisition of Clinical Devices B.V.	4,836
Balance, May 31, 2014	$	360,473
Tax basis adjustment	779
Balance, May 31, 2015	$	361,252

Income Taxes (Tables)

12 Months Ended

May 31, 2015

Income Tax Disclosure [Abstract]

Components of income (loss) before income tax provision

The components of income (loss) before income tax provision for the years ended May 31 are as follows:



	2015			2014		2013
	(in thousands)
(Loss) income before tax provision:
US	$	(8,833	)	$	5,199	$	(3,614	)
Non-US	834			541		2,027
	$	(7,999	)	$	5,740	$	(1,587	)

Summary of Income tax (benefit) provision analyzed by category



	2015			2014			2013
	(in thousands)
Current
Federal	$	(242	)	$	(133	)	$	(1,622	)
State and local	205			99			(52		)
Non U.S.	417			157			468
	380			123			(1,206		)
Deferred	(5,111		)	2,951			830
Income tax (benefit) provision	$	(4,731	)	$	3,074		$	(376	)

Summary of significant components of deferred income tax (benefit) expense from operations

The significant components of deferred income tax (benefit) expense from operations for the years ended May 31 consist of the following:



	2015			2014		2013
	(in thousands)
Deferred tax benefit	$	(1,916	)	$	1,778	$	830
Impact of NYS tax reform legislation	—			1,173		—
Net operating loss carryforward	(3,195		)	—		—
	$	(5,111	)	$	2,951	$	830

Summary of deferred tax asset and liabilities



	May 31, 2015			May 31, 2014
	(in thousands)
Deferred tax assets
Net operating loss carryforward	$	51,785		$	48,749
Stock-based compensation	4,468			4,851
Federal and state R&D tax credit carryforward	1,646			1,249
Inventories	2,808			875
Expenses incurred not currently deductible	2,107			1,379
Accrued liabilities	114			154
Gross deferred tax asset	62,928			57,257
Deferred tax liabilities
Excess tax over book depreciation and amortization	42,988			41,843
	42,988			41,843
Valuation Allowance	(1,791		)	(1,532		)
Net deferred tax asset	$	18,149		$	13,882

Summary of Income tax rate reconciliation



	2015			2014			2013
	(in thousands)
Income tax (benefit) provision at statutory tax rate of 35%	$	(2,800	)	$	2,008		$	(555	)
Effect of graduated tax rates	80			(57		)	(16		)
State income taxes, net of Federal tax benefit	(17		)	122			95
State income tax credits, net of Federal tax benefit	—			—			(23		)
Impact of Non US operations	133			(27		)	(228		)
Research and development tax credit	(604		)	(236		)	(142		)
Nondeductible acquisition costs	—			—			110
Nondeductible interest on contingent payments	265			540			130
Nontaxable gain on revaluation of contingent consideration liability	(3,138		)	(1,698		)	—
Tax law changes	(454		)	1,173			—
Effect of elimination of stock compensation APIC pool	1,253			440			—
Nondeductible stock-based compensation	—			176			108
Other nondeductible expenses	498			384			336
Over (under) accrual of prior year Federal and state taxes	38			249			(10		)
Fully reserved capital losses	—			—			(179		)
Other	15			—			(2		)
Income tax (benefit) expense	$	(4,731	)	$	3,074		$	(376	)

Stockholders' Equity (Tables)

12 Months Ended

May 31, 2015

Equity [Abstract]

Schedule summarizes stock option activity

The following table summarizes information about stock options activity for the fiscal year ended May 31, 2015.



	2015
	Shares		Weighted- average exercise price		Weighted average remaining contractual life	Aggregate intrinsic value (in thousands)
Outstanding at beginning of year	2,673,751		$	14.82
Granted	561,883		$	16.14
Exercised	(423,804	)	$	13.87
Forfeited	(261,738	)	$	14.71
Expired	(250,779	)	$	17.98
Outstanding at end of year	2,299,313		$	14.86	3.89	$	4,571
Options exercisable at year-end	1,271,028		$	15.10	2.58	$	2,547
Options expected to vest in future periods	903,143		$	14.56	5.52	$	1,778

Summary of weighted average fair value of options granted

Schedule of weighted-average fair value assumptions

Summary of options outstanding

Share based compensation arrangement by share based payment award nonvested shares and weighted average grant date fair value



	Non-Vested Stock Award Units		Weighted Average Grant-Date Fair Value
Non-vested at beginning of year	587,991		$	14.82
Granted	242,158		$	14.75
Vested	(160,207	)	$	14.83
Canceled	(106,841	)	$	12.33
Non-vested at end of year	563,101		$	13.73
Awards expected to vest in future periods	492,432		$	13.73

Summary of future expense for awards outstanding

Summary of stock-based compensation in accordance with authoritative guidance on share based payment awards

Segments and Geographic Information (Tables)

12 Months Ended

May 31, 2015

Segment Reporting [Abstract]

Summary of total net sales by product category

Total sales by product category are summarized below (in thousands):



	Year Ended
	May 31, 2015		May 31, 2014		May 31, 2013
Net sales by Product Category
Peripheral Vascular	$	192,833	$	192,626	$	179,573
Vascular Access	107,874		106,394		106,690
Oncology/Surgery	52,090		49,360		47,155
Supply Agreement	4,177		6,045		8,498
Total	$	356,974	$	354,425	$	341,916

Summary of net sales for geographic areas

Total sales for geographic areas are summarized below (in thousands):



	Year Ended
	May 31, 2015		May 31, 2014		May 31, 2013
Net sales by Geography
United States	$	280,851	$	280,161	$	266,228
International	71,946		68,219		67,190
Supply Agreement	4,177		6,045		8,498
Total	$	356,974	$	354,425	$	341,916

Basis of Presentation, Business Description and Summary of Significant Accounting Policies (Details 4)	12 Months Ended
	May 31, 2015	May 31, 2014	May 31, 2013
Reconciliation of the weighted-average number of common shares
Basic	35,683,139	35,135,689	34,817,279
Effect of dilutive securities	0	304,161	0
Diluted	35,683,139	35,439,850	34,817,279

Basis of Presentation, Business Description and Summary of Significant Accounting Policies (Details Textual) (USD $)	0 Months Ended					1 Months Ended				3 Months Ended	9 Months Ended	12 Months Ended			3 Months Ended		0 Months Ended	12 Months Ended	0 Months Ended	12 Months Ended					3 Months Ended
	Mar. 31, 2014 Observation	Feb. 04, 2014 Observation	Dec. 05, 2013	Feb. 13, 2012 Observation	Feb. 10, 2012 Observation	Apr. 21, 2014	Feb. 25, 2014	Sep. 24, 2012 Observation	Mar. 05, 2012	Feb. 28, 2015	Feb. 28, 2014	May 31, 2015 Investment	May 31, 2014	May 31, 2013	Feb. 28, 2015 Trademarks [Member]	May 31, 2012 Navylist [Member] Trademarks [Member]	Dec. 05, 2013 Maximum [Member]	May 31, 2015 Maximum [Member]	Dec. 05, 2013 Minimum [Member]	May 31, 2015 Minimum [Member]	May 31, 2015 Machinery and Equipment [Member]	May 31, 2015 Computer Equipment [Member] Maximum [Member]	May 31, 2015 Computer Equipment [Member] Minimum [Member]	Apr. 09, 2015 EmboMedics Inc. [Member]	Feb. 28, 2015 Morpheus PICC recall and product line discontinuance [Member]	Feb. 28, 2015 Cost of Sales [Member] Morpheus PICC recall and product line discontinuance [Member]	Feb. 28, 2015 Restructuring And Other Items [Member] Morpheus PICC recall and product line discontinuance [Member]
Business Acquisition [Line Items]
Operational Excellence Program Expected Savings																	$ 18,000,000		$ 15,000,000
Property, Plant and Equipment, Useful Life																					39 years	10 years	3 years
Costs for quality call to action program													3,200,000
Number of observations	3	1		6	12			5
Number of business days to provide response to FDA						15 days	15 days		15 days		15 days
Short Term Investments Maturity Period												less than three months
Investments in auction rate securities that failed auctions												1,700,000
Number of investments												2
Accounts receivables period due																		90 days		30 days
Weighted average useful life																		15 years		3 years
Restocking charge percentage												20.00%
Undamaged product expiration date																				12 months
Estimated net operating losses, prior to utilization												5,400,000
Potential amount of undiscounted future contingent consideration												54,000,000
Notional amount of interest rate swap agreement												100,000,000
Antidilutive securities excluded from computation of diluted earnings per share												2,862,414,000	2,347,426,000	2,904,944,000
Business Development Program Period			3 years
Restructuring Charges																									6,100,000
Inventory Write-down																										4,800,000
Other Restructuring Costs																											1,000,000
Impairment of Long-Lived Assets to be Disposed of										8,200,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Indefinite-Lived Intangible Assets																28,600,000
Impairment of Intangible Assets, Indefinite-lived (Excluding Goodwill)															6,400,000
Equity Method Investments																								2,000,000
Equity Method Investments, Optional Additional Equity Investment																								$ 9,000,000

Acquisitions (Details Textual) (USD $)	0 Months Ended				1 Months Ended				9 Months Ended					12 Months Ended						0 Months Ended		0 Months Ended				0 Months Ended
Acquisitions (Details Textual) (USD $)	Mar. 31, 2014 Observation	Feb. 04, 2014 Observation	Feb. 13, 2012 Observation	Feb. 10, 2012 Observation	Apr. 21, 2014	Feb. 25, 2014	Sep. 24, 2012 Observation	Mar. 05, 2012	Feb. 28, 2014	May 31, 2015	May 31, 2014	Sep. 19, 2013	May 31, 2013	May 31, 2015 Customer relationships [Member]	May 31, 2014 Customer relationships [Member]	May 31, 2015 Trademarks [Member]	May 31, 2014 Trademarks [Member]	May 31, 2015 Maximum [Member]	May 31, 2015 Minimum [Member]	Aug. 15, 2013 Clinical Devices, B.V. [Member]	Aug. 15, 2013 Clinical Devices, B.V. [Member]	Aug. 15, 2013 Clinical Devices, B.V. [Member] Customer relationships [Member]	Aug. 15, 2013 Clinical Devices, B.V. [Member] Customer relationships [Member]	Aug. 15, 2013 Clinical Devices, B.V. [Member] Trademarks [Member]	Aug. 15, 2013 Clinical Devices, B.V. [Member] In Process Research and Development [Member]	Aug. 15, 2013 Cash [Member] Clinical Devices, B.V. [Member]	Apr. 09, 2015 EmboMedics Inc. [Member]
Acquisitions (Additional Textual) [Abstract]
Investment in company																											$ 2,000,000
Cash payments at closing total																										3,700,000
Total estimated purchase consideration																				8,700,000
Estimated fair value contingent consideration																					5,000,000
Goodwill										361,252,000	360,473,000		355,637,000								4,800,000
Weighted average useful life														12 years	10 years 2 months 12 days	10 years 8 months 12 days	8 years	15 years	3 years			15 years
Senior secured term loan facility												100,000,000
Intangible assets acquired other than goodwill																					5,100,000				3,600,000
Stock purchase agreement payment holdback																					400,000
Customer relationships																							1,400,000
Trademarks																								100,000
Deferred tax liability																					1,200,000
Equity Method Investments, Optional Additional Equity Investment																											$ 9,000,000
Number of Observations	3	1	6	12			5
Number of Business Days to Provide Response					15 days	15 days		15 days	15 days

Fair Value of Financial Instruments Fair Value of Financial Instruments (Details) (Recurring [Member], USD $) In Thousands, unless otherwise specified	May 31, 2015	May 31, 2014
Financial Assets
Cash equivalents		$ 445
Marketable securities	1,689	1,809
Total Financial Assets	1,689	2,254
Financial Liabilities
Total Financial Liabilities	47,641	67,886
Interest rate swap agreements [Member]
Financial Liabilities
Total Financial Liabilities	257	555
Contingent liability for acquisition earn out [Member]
Financial Liabilities
Total Financial Liabilities	47,384	67,331
U.S. government agency obligations [Member]
Financial Assets
Marketable securities	1,689	1,809
Money market funds [Member]
Financial Assets
Cash equivalents		445
Level 1 [Member]
Financial Assets
Cash equivalents		445
Marketable securities	0	0
Total Financial Assets	0	445
Financial Liabilities
Total Financial Liabilities	0	0
Level 1 [Member] \| Interest rate swap agreements [Member]
Financial Liabilities
Total Financial Liabilities	0	0
Level 1 [Member] \| Contingent liability for acquisition earn out [Member]
Financial Liabilities
Total Financial Liabilities	0	0
Level 1 [Member] \| U.S. government agency obligations [Member]
Financial Assets
Marketable securities	0	0
Level 1 [Member] \| Money market funds [Member]
Financial Assets
Cash equivalents		445
Level 2 [Member]
Financial Assets
Cash equivalents		0
Marketable securities	0	0
Total Financial Assets	0	0
Financial Liabilities
Total Financial Liabilities	257	555
Level 2 [Member] \| Interest rate swap agreements [Member]
Financial Liabilities
Total Financial Liabilities	257	555
Level 2 [Member] \| Contingent liability for acquisition earn out [Member]
Financial Liabilities
Total Financial Liabilities	0	0
Level 2 [Member] \| U.S. government agency obligations [Member]
Financial Assets
Marketable securities	0	0
Level 2 [Member] \| Money market funds [Member]
Financial Assets
Cash equivalents		0
Level 3 [Member]
Financial Assets
Cash equivalents		0
Marketable securities	1,689	1,809
Total Financial Assets	1,689	1,809
Financial Liabilities
Total Financial Liabilities	47,384	67,331
Level 3 [Member] \| Interest rate swap agreements [Member]
Financial Liabilities
Total Financial Liabilities	0	0
Level 3 [Member] \| Contingent liability for acquisition earn out [Member]
Financial Liabilities
Total Financial Liabilities	47,384	67,331
Level 3 [Member] \| U.S. government agency obligations [Member]
Financial Assets
Marketable securities	1,689	1,809
Level 3 [Member] \| Money market funds [Member]
Financial Assets
Cash equivalents		$ 0

Fair Value of Financial Instruments Fair Value of Financial Instruments (Details 2) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	May 31, 2015	May 31, 2014
Fair Value Measurements using Significant Unobservable Inputs
Balance, May 31, 2013, Financial Assets	$ 1,809	$ 1,850
Balance, May 31, 2013, Financial Liabilities	67,331	75,049
Total gains or losses (realized/unrealized):
Included in earnings, Financial Assets	0	0
Earnings revaluation gain - Included in Earnings, Financial Liabilities	(8,196)	(1,808)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Change In Contingent Consideration		0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Change In Contingent Consideration		4,970
Earnings revaluation expense - Included in Earnings, Financial Liabilities	(529)	0
Included in other comprehensive income, Financial Assets	(120)	(41)
Included in other comprehensive income, Financial Liabilities	0	0
Transfers in and/or (out) of Level 3, Financial Assets	0	0
Transfers in and/or (out) of Level 3, Financial Liabilities	(11,222)	(10,880)
Balance, May 31, 2014, Financial Assets		1,809
Balance, May 31, 2014, Financial Liabilities		67,331
Fair Value Measurement with Unobservable Inputs Reconciliation Recurring Basis Liability Contingent Consideration Earn Out Asset	1,689
Fair Value Measurement with Unobservable Inputs Reconciliation Recurring Basis Liability Contingent Consideration Earn Out Liability	$ 47,384

Fair Value of Financial Instruments Fair Value of Financial Instruments (Details 3) (USD $)	12 Months Ended
	May 31, 2015	May 31, 2014	May 31, 2013
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Potential amount of undiscounted future contingent consideration	$ 54,000,000
Contingent consideration liability at fair value		67,331,000	75,049,000
Summary showing the recurring fair value measurements of the contingent consideration liability
Discount rate used in fair value calculation	12.00%
Level 3 [Member] \| Contingent Consideration Earn Out Liability [Member] \| Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Contingent consideration liability at fair value	47,384,000
Revenue Based Payment [Member] \| Level 3 [Member] \| Contingent Consideration Earn Out Liability [Member] \| Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Contingent consideration liability at fair value	44,716,000
Revenue Based Payment [Member] \| Level 3 [Member] \| Maximum [Member] \| Contingent Consideration Earn Out Liability [Member] \| Recurring [Member]
Summary showing the recurring fair value measurements of the contingent consideration liability
Discount rate used in fair value calculation	10.00%
Probability of payment	100.00%
Projected fiscal year of payment	2022
Revenue Based Payment [Member] \| Level 3 [Member] \| Minimum [Member] \| Contingent Consideration Earn Out Liability [Member] \| Recurring [Member]
Summary showing the recurring fair value measurements of the contingent consideration liability
Discount rate used in fair value calculation	4.00%
Probability of payment	75.00%
Projected fiscal year of payment	2015
Milestone Based Payments [Member] \| Level 3 [Member] \| Contingent Consideration Earn Out Liability [Member] \| Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Contingent consideration liability at fair value	$ 2,668,000
Summary showing the recurring fair value measurements of the contingent consideration liability
Discount rate used in fair value calculation	16.00%
Projected fiscal year of payment	2015
Milestone Based Payments [Member] \| Level 3 [Member] \| Maximum [Member] \| Contingent Consideration Earn Out Liability [Member] \| Recurring [Member]
Summary showing the recurring fair value measurements of the contingent consideration liability
Probability of payment	100.00%
Milestone Based Payments [Member] \| Level 3 [Member] \| Minimum [Member] \| Contingent Consideration Earn Out Liability [Member] \| Recurring [Member]
Summary showing the recurring fair value measurements of the contingent consideration liability
Probability of payment	75.00%

Marketable Securities and Investments (Details) (USD $)	May 31, 2015 Investment	May 31, 2014
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Failed Auction, Value	$ 1,700,000
Marketable securities
Amortized cost	1,825,000	1,825,000
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(136,000)	(16,000)
Fair Value	1,689,000	1,809,000
Number of Investments Failed at Auction	2
U.S. government agency obligations [Member]
Marketable securities
Amortized cost	1,825,000	1,825,000
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(136,000)	(16,000)
Fair Value	$ 1,689,000	$ 1,809,000

Marketable Securities and Investments (Details 1) (USD $) In Thousands, unless otherwise specified	May 31, 2015	May 31, 2014
Amortized cost and fair value of marketable securities by contractual maturity
Amortized cost, Due in one year or less	$ 0
Amortized cost, Due after one through five years	0
Amortized cost, Due after five through twenty years	1,825
Amortized cost	1,825	1,825
Fair Value, Due in one year or less	0
Fair Value, Due after one through five years	0
Fair Value, Due after five through twenty years	1,689
Fair Value, Total	$ 1,689

Inventories (Details) (USD $) In Thousands, unless otherwise specified	May 31, 2015	May 31, 2014
Inventories
Raw materials	$ 28,040	$ 24,734
Work in process	11,910	11,992
Finished goods	27,438	24,508
Total	$ 67,388	$ 61,234

Prepaid Expenses and Other (Details) (USD $) In Thousands, unless otherwise specified	May 31, 2015	May 31, 2014
Prepaid expenses and other
Deposits	$ 2,011	$ 3,356
Other prepaid taxes	165	202
License fees	121	604
Software licenses	667	130
Trade shows	279	62
Rent	77	114
Other	1,463	1,003
Total	$ 4,783	$ 5,471

- Definition

Amount of asset related to consideration paid in advance for rent that provides economic benefits within a future period of one year or the normal operating cycle, if longer.

+ References+ Details

Property, Plant, and Equipment, at Cost (Details) (USD $)	12 Months Ended
	May 31, 2015	May 31, 2014	May 31, 2013
Property, plant and equipment
Property, plant and equipment	$ 89,053,000	$ 103,406,000
Less accumulated depreciation and amortization	(36,197,000)	(37,845,000)
Property, plant and equipment excluding land and land improvements	52,856,000	65,561,000
Land and land improvements	1,704,000	1,029,000
Property, plant and equipment, Net	54,560,000	66,590,000
Depreciation expense	9,800,000	8,400,000	8,700,000
Additional depreciation due to change in useful life	1,500,000	800,000	0
Trade shows	279,000	62,000
Building and building improvements [Member]
Property, plant and equipment
Property, plant and equipment	33,853,000	33,126,000
Estimated useful lives	39 years
Machinery and equipment [Member]
Property, plant and equipment
Property, plant and equipment	23,626,000	31,880,000
Machinery and equipment [Member] \| Minimum [Member]
Property, plant and equipment
Estimated useful lives	3 years
Machinery and equipment [Member] \| Maximum [Member]
Property, plant and equipment
Estimated useful lives	8 years
Computer software and equipment [Member]
Property, plant and equipment
Property, plant and equipment	24,431,000	25,836,000
Computer software and equipment [Member] \| Minimum [Member]
Property, plant and equipment
Estimated useful lives	3 years
Computer software and equipment [Member] \| Maximum [Member]
Property, plant and equipment
Estimated useful lives	10 years
Construction in progress [Member]
Property, plant and equipment
Property, plant and equipment	$ 7,143,000	$ 12,564,000

Goodwill and Intangible Assets (Details) (USD $)	3 Months Ended	12 Months Ended
Goodwill and Intangible Assets (Details) (USD $)	May 31, 2014	May 31, 2014	May 31, 2015	Aug. 15, 2013 Clinical Devices, B.V. [Member]
Adjustments to Goodwill
Goodwill, Beginning Balance		$ 355,637,000	$ 361,252,000	$ 4,800,000
Goodwill recognized from business combination and asset acquisition		4,836,000
Adjustments to Navilyst purchase price allocation	500,000
Goodwill, Ending Balance	$ 360,473,000	$ 360,473,000	$ 361,252,000	$ 4,800,000

Goodwill and Intangible Assets (Details 1) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	May 31, 2015	May 31, 2014
Indefinite-lived Intangible Assets [Line Items]
Gross carrying value, finite and indefinite intangible assets total	$ 276,105	$ 284,027
Accumulated amortization	(94,299)	(78,771)
Net carrying value, finite and indefinite intangible assets total	181,806	205,256
Customer relationships [Member]
Indefinite-lived Intangible Assets [Line Items]
Gross carrying value, finite-lived intangible assets	86,371	150,298
Accumulated amortization	(42,813)	(32,930)
Net carrying value, finite-lived intangible assets	43,558	117,368
Weighted average useful life	12 years	10 years 2 months 12 days
Product technologies [Member]
Indefinite-lived Intangible Assets [Line Items]
Gross carrying value, finite-lived intangible assets	148,776	86,645
Accumulated amortization	(41,447)	(37,848)
Net carrying value, finite-lived intangible assets	107,329	48,797
Weighted average useful life	10 years 2 months 12 days	11 years 10 months 24 days
Licenses [Member]
Indefinite-lived Intangible Assets [Line Items]
Gross carrying value, finite-lived intangible assets	7,913	7,639
Accumulated amortization	(5,910)	(5,211)
Net carrying value, finite-lived intangible assets	2,003	2,428
Weighted average useful life	8 years 3 months 18 days	8 years 4 months 24 days
Trademarks [Member]
Indefinite-lived Intangible Assets [Line Items]
Gross carrying value, finite-lived intangible assets		6,345
Accumulated amortization	(3,229)	(1,882)
Net carrying value, finite-lived intangible assets		4,463
Weighted average useful life	10 years 8 months 12 days	8 years
Distributor relationships [Member]
Indefinite-lived Intangible Assets [Line Items]
Gross carrying value, finite-lived intangible assets	900	900
Accumulated amortization	(900)	(900)
Net carrying value, finite-lived intangible assets	0	0
Weighted average useful life	3 years	3 years
Trademark-NAMIC [Member]
Indefinite-lived Intangible Assets [Line Items]
Gross carrying value, indefinite-lived intangible assets	28,545	28,600
Net carrying value, indefinite-lived intangible assets	25,316	28,600
In-process R&D acquired [Member]
Indefinite-lived Intangible Assets [Line Items]
Gross carrying value, indefinite-lived intangible assets	3,600	3,600
Net carrying value, indefinite-lived intangible assets	$ 3,600	$ 3,600

Goodwill and Intangible Assets (Details 2) (USD $) In Thousands, unless otherwise specified	May 31, 2015
Expected amortization expense
2015	$ 18,452
2016	18,568
2017	19,388
2018	21,499
2019	$ 22,741

Goodwill and Intangible Assets (Details Textual) (USD $)	3 Months Ended	12 Months Ended				12 Months Ended		0 Months Ended	3 Months Ended	12 Months Ended
	May 31, 2014	May 31, 2015	May 31, 2014	May 31, 2013	Dec. 31, 2013	May 31, 2015 Maximum [Member]	May 31, 2015 Minimum [Member]	Dec. 31, 2014 Income Approach Valuation Technique [Member]	Feb. 28, 2015 Income Approach Valuation Technique [Member]	May 31, 2014 Income Approach Valuation Technique [Member]	May 31, 2014 Market Approach Valuation Technique [Member]	May 31, 2015 Trademark-NAMIC [Member]	May 31, 2015 Customer Relationships [Member]	May 31, 2014 Customer Relationships [Member]	May 31, 2015 Trademarks [Member]	May 31, 2014 Trademarks [Member]
Goodwill and Intangible Assets (Textual) [Abstract]
Estimates useful life of intangible assets other than goodwill						15 years	3 years					12 years	12 years	10 years 2 months 12 days	10 years 8 months 12 days	8 years
Weight assigned to valuation methods										75.00%	25.00%
Fair Value Inputs, Capitalization Rate		8.00%
Discount rate used in fair value calculation		12.00%						12.00%
Percentage of fair value, carrying value					18.00%
Change in carrying value of goodwill related to working capital	$ 500,000
Amortization expense		17,912,000	16,622,000	16,617,000
Fair Value Inputs, Long-term Revenue Growth Rate								3.00%
Fair Value Inputs Royalty Rate								3.00%
Impairment of Intangible Assets, Indefinite-lived (Excluding Goodwill)								6,400,000	6,400,000
Goodwill And Deferred Tax Liabilities, Purchase Accounting Adjustments		$ 800,000

Goodwill and Intangible Assets Goodwill and Intangible Assets (Details 3) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	May 31, 2015	May 31, 2014
Goodwill [Roll Forward]
Goodwill, Beginning Balance	$ 360,473	$ 355,637
Goodwill recognized from business combination and asset acquisition		4,836
Tax basis adjustment	779
Goodwill, Ending Balance	$ 361,252	$ 360,473

Income Taxes (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	May 31, 2015	May 31, 2014	May 31, 2013
Components of income (loss) before income tax provision
US	$ (8,833)	$ 5,199	$ (3,614)
Non-US	834	541	2,027
Total other (expenses) income, net	$ (7,999)	$ 5,740	$ (1,587)

Income Taxes (Details 1) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	May 31, 2015	May 31, 2014	May 31, 2013
Current
Federal	$ (242)	$ (133)	$ (1,622)
State and local	205	99	(52)
Non U.S.	417	157	468
Current, Total	380	123	(1,206)
Deferred	(5,111)	2,951	830
Income tax expense/(benefit), Total	$ (4,731)	$ 3,074	$ (376)

- Definition

Amount of current federal tax expense (benefit) pertaining to income (loss) from continuing operations.

+ References+ Details

- Definition

Amount of current income tax expense (benefit) pertaining to taxable income (loss) from continuing operations.

+ References+ Details

- Definition

Amount of current state and local tax expense (benefit) pertaining to income (loss) from continuing operations.

+ References+ Details

- Definition

Amount of deferred income tax expense (benefit) pertaining to income (loss) from continuing operations.

+ References+ Details

Income Taxes (Details 2) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	May 31, 2015	May 31, 2014	May 31, 2013
Summary of significant components of deferred income tax (benefit) expense from operations
Deferred tax expense (benefit)	$ (1,916)	$ 1,778	$ 830
Impact of NYS tax reform legislation	0	1,173	0
Net operating loss carryforward	(3,195)	0	0
Deferred Income Tax Expense (Benefit)	$ (5,111)	$ 2,951	$ 830

- Definition

Amount of deferred income tax expense (benefit) pertaining to income (loss) from continuing operations.

+ References+ Details

Income Taxes (Details 3) (USD $) In Thousands, unless otherwise specified	May 31, 2015	May 31, 2014
Deferred tax assets
Net operating loss carryforward	$ 51,785	$ 48,749
Stock-based compensation	4,468	4,851
Federal and state R&D tax credit carryforward	1,646	1,249
Inventories	2,808	875
Expenses incurred not currently deductible	2,107	1,379
Deferred revenue	114	154
Gross deferred tax asset	62,928	57,257
Deferred tax liabilities
Excess tax over book depreciation and amortization	42,988	41,843
Gross deferred Liability	42,988	41,843
Valuation Allowance	(1,791)	(1,532)
Net deferred tax asset	$ 18,149	$ 13,882

Income Taxes (Details 4) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	May 31, 2015	May 31, 2014	May 31, 2013
Reasons for consolidated income tax provision
Income tax (benefit) provision at statutory tax rate of 35%	$ (2,800)	$ 2,008	$ (555)
Effect of Graduated tax rates	80	(57)	(16)
State income taxes, net of Federal tax benefit	(17)	122	95
State income tax credits, net of Federal tax benefit	0	0	(23)
Impact of Non US operations	133	(27)	(228)
Research and development tax credit	(604)	(236)	(142)
Nondeductible acquisition costs	0	0	110
Nondeductible interest on contingent payments	265	540	130
Nontaxable gain on revaluation of contingent consideration liability	(3,138)	(1,698)	0
Tax law change	(454)	1,173	0
Effect of elimination of ASC 718 APIC pool	1,253	440	0
Nondeductible stock-based compensation	0	176	108
Other nondeductible expenses	498	384	336
Overaccrual (underaccrual) of prior year Federal and state taxes	38	249	(10)
Fully reserved capital losses	0	0	(179)
Other	15	0	(2)
Income tax expense/(benefit), Total	$ (4,731)	$ 3,074	$ (376)

Income Taxes (Details Textual) (USD $)	12 Months Ended
Income Taxes (Details Textual) (USD $)	May 31, 2015	May 31, 2014
Income Tax [Line Items]
Deferred Tax Assets, Net, Potential Additional Amount Due To Valuation Allowance Of Deferred Tax Liabilities	$ 15,300,000
Income Taxes (Textual) [Abstract]
Stockholders' Equity, Period Increase (Decrease), Potential Recognition Of Tax Deductions For Compensation Greater Than Compensation Recognized	300,000
Net deferred tax asset	18,149,000	13,882,000
Remaining federal net operating loss	26,100,000
State net operating loss expire prior to utilization	5,400,000
Net deferred income tax asset	18,149,000
Valuation Allowance	(1,791,000)	(1,532,000)
Increase decrease valuation allowance	300,000	800,000
Effective income tax rate	35.00%
Accrued interest and penalties recognized	0	0
Beginning of open tax year range	2011
End of open tax year range	2015
Foreign subsidiary undistributed earnings	4,000,000
State [Member]
Income Taxes (Textual) [Abstract]
Federal and State net operating loss carryforwards	34,800,000
Federal [Member]
Income Taxes (Textual) [Abstract]
Federal and State net operating loss carryforwards	173,700,000
Operating loss carryforwards from acquired companies	161,500,000
Operating Loss Carryforwards, Amount After Limitation Of Use	147,600,000
Net deferred income tax asset	19,300,000
Tax Year 2017 To 2016 [Member] \| Federal [Member]
Income Taxes (Textual) [Abstract]
Federal and State net operating loss carryforwards	30,700,000
Tax Year 2027 To 2033 [Member] \| Federal [Member]
Income Taxes (Textual) [Abstract]
Operating Loss Carryforwards, Amount After Limitation Of Use	117,000,000
Tax Year 2015 To 2033 [Member] \| State [Member]
Income Taxes (Textual) [Abstract]
Federal and State net operating loss carryforwards	$ 29,400,000

Accrued Liabilities (Details) (USD $) In Thousands, unless otherwise specified	May 31, 2015	May 31, 2014
Accrued liabilities
Payroll and related expenses	$ 10,330	$ 8,114
Royalties	2,237	2,620
Accrued severance	158	765
Sales and franchise taxes	808	154
Interest rate swap liability	489	1,327
Accrued Professional Fees	1,522	983
Outside services	257	555
Other	2,530	2,733
Total	$ 18,331	$ 17,251

Long-Term Debt (Details1) (Term Loan [Member], USD $) In Thousands, unless otherwise specified	May 31, 2015
Term Loan [Member]
Future minimum principal payments on long-term debt
2015	$ 8,750
2016	13,750
2017	26,250
2018	88,910
2019	0
Bank Notes	$ 137,660

- Definition

Carrying amount of long-term debt, net of unamortized discount or premium, including current and noncurrent amounts. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

+ References+ Details

Long-Term Debt (Details Textual) (USD $)	12 Months Ended			12 Months Ended		12 Months Ended					0 Months Ended
Long-Term Debt (Details Textual) (USD $)	May 31, 2015	May 31, 2014	Sep. 19, 2013	May 31, 2015 Line of Credit [Member]	May 31, 2014 Revolving Credit Facility [Member]	May 31, 2015 Term Loan [Member]	May 31, 2015 Maximum [Member]	May 31, 2015 Minimum [Member]	Sep. 19, 2013 Letter of Credit [Member]	Sep. 19, 2013 Swingline Loans [Member]	Sep. 19, 2013 Revolving Credit Facility [Member]	May 31, 2015 Interest Rate Swap [Member]
Debt Instrument [Line Items]
Senior secured term loan facility			$ 100,000,000
Senior secured revolving credit facility			100,000,000
Credit facility borrowing capacity									20,000,000	5,000,000
Bank credit agreement maturity period	P5Y
Quarterly percentage repayment of term facility year one	5.00%
Quarterly percentage repayment of term facility year two	5.00%
Quarterly percentage repayment of term facility year three	10.00%
Quarterly percentage repayment of term facility year four	15.00%
Quarterly percentage repayment of term facility year five	65.00%
Percentage of increases leverage ratio base rate, minimum				1.50%		0.50%
Percentage of increases leverage ratio base rate, maximum				2.25%		1.25%
Percentage of increase in interest	2.00%
Commitment fee percentage							0.35%	0.20%
Notional amount of interest rate swap agreement	100,000,000
Fixed interest rate payments	0.74%											3.26%
Borrowing under Revolving Facility											41,400,000
Loans Payable						91,300,000
Loans payable, noncurrent	$ 128,910,000	$ 137,660,000			$ 46,400,000
Ratio for debt service coverage	1.35
Ratio of indebtedness to consolidated EBITDA	3.75

Stockholders' Equity (Details) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	May 31, 2015
Schedule summarizes stock option activity
Shares Outstanding at beginning of year	2,673,751
Shares Granted	561,883
Shares Exercised	(423,804)
Shares Forfeited	(261,738)
Shares Expired	(250,779)
Shares Outstanding at end of year	2,299,313
Shares Options exercisable at year end	1,271,028
Shares Option expected to vest in future periods	903,143
Weighted Average exercise price, Outstanding at beginning of year	$ 14.82
Weighted Average exercise price Granted	$ 16.14
Weighted Average exercise price Exercised	$ 13.87
Weighted Average exercise price Forfeited	$ 14.71
Weighted Average exercise price Expired	$ 17.98
Weighted Average exercise price, Outstanding at end of year	$ 14.86
Weighted Average exercise price, Options exercisable at year end	$ 15.10
Weighted Average exercise price, Options expected to vest in future periods	$ 14.56
Weighted Average remaining contractual life	3 years 10 months 20 days
Weighted Average remaining contractual life, Option exercisable at year end	2 years 6 months 29 days
Weighted Average remaining contractual life, Option expected to vest in future periods	5 years 6 months 7 days
Aggregate intrinsic value, Outstanding at end of year	$ 4,571
Aggregate intrinsic value, Options exercisable at year end	2,547
Aggregate intrinsic value, Option expected to vest in future periods	$ 1,778

Stockholders' Equity (Details 2)	12 Months Ended
Stockholders' Equity (Details 2)	May 31, 2015	May 31, 2014	May 31, 2013
Schedule of weighted-average fair value assumptions
Expected stock price volatility	31.00%	34.40%	43.91%
Risk-free interest rate	1.54%	1.44%	0.62%
Expected life of options	4 years 9 months 3 days	4 years 8 months 25 days	4 years 7 months 13 days

Stockholders' Equity (Details 3) (USD $)	12 Months Ended
Stockholders' Equity (Details 3) (USD $)	May 31, 2015
Options outstanding
Number outstanding	2,299,313
Weighted- average remaining life in years	3 years 10 months 20 days
Weighted- average exercise price	$ 14.86
Number Exercisable	1,271,028
Weighted- average exercise price	$ 15.10
Range One [Member]
Options outstanding
Range of exercise prices, Lower limit	$ 10.25
Range of exercise prices, Upper limit	$ 14.24
Number outstanding	1,403,859
Weighted- average remaining life in years	4 years 1 month 2 days
Weighted- average exercise price	$ 12.94
Number Exercisable	793,406
Weighted- average exercise price	$ 13.03
Range Two [Member]
Options outstanding
Range of exercise prices, Lower limit	$ 14.25
Range of exercise prices, Upper limit	$ 18.24
Number outstanding	564,416
Weighted- average remaining life in years	4 years 1 month 17 days
Weighted- average exercise price	$ 15.96
Number Exercisable	251,584
Weighted- average exercise price	$ 15.51
Range Three [Member]
Options outstanding
Range of exercise prices, Lower limit	$ 18.25
Range of exercise prices, Upper limit	$ 22.24
Number outstanding	217,069
Weighted- average remaining life in years	3 years 9 months
Weighted- average exercise price	$ 19.38
Number Exercisable	112,069
Weighted- average exercise price	$ 19.35
Range Four [Member]
Options outstanding
Range of exercise prices, Lower limit	$ 22.25
Range of exercise prices, Upper limit	$ 26.24
Number outstanding	99,908
Weighted- average remaining life in years	5 months 4 days
Weighted- average exercise price	$ 23.94
Number Exercisable	99,908
Weighted- average exercise price	$ 23.94
Range Five [Member]
Options outstanding
Range of exercise prices, Lower limit	$ 26.25
Range of exercise prices, Upper limit	$ 30.24
Number outstanding	14,061
Weighted- average remaining life in years	11 months 8 days
Weighted- average exercise price	$ 28.10
Number Exercisable	14,061
Weighted- average exercise price	$ 28.10

Stockholders' Equity (Details 4) (USD $)	12 Months Ended
Stockholders' Equity (Details 4) (USD $)	May 31, 2015	May 31, 2014	May 31, 2013
Share Based Compensation Arrangement by Share Based Payment Award Nonvested Shares and Weighted Average Grant Date Fair Value [Abstract]
Non-Vested Stock Award Units Beginning Balance	587,991
Non-Vested Stock Award Units, Granted	242,158
Non-Vested Stock Award Units, Cancelled	(160,207)
Non-Vested Stock Award Units, Vested	(106,841)
Non-Vested Stock Award Units Ending Balance	563,101	587,991
Non-Vested Stock Award Units, Awards expected to vest in future periods	492,432,000
Weighted Average Grant-Date Fair Value Beginning Balance	$ 14.82
Weighted Average Grant-Date Fair Value, Granted	$ 14.75	$ 13.23	$ 10.79
Weighted Average Grant-Date Fair Value, Cancelled	$ 14.83
Weighted Average Grant-Date Fair Value, Vested	$ 12.33
Weighted Average Grant-Date Fair Value Ending Balance	$ 13.73	$ 14.82
Weighted Average Grant-Date Fair Value, Awards expected to vest in future periods	$ 13,730.00

Stockholders' Equity (Details 6) (USD $)	12 Months Ended
Stockholders' Equity (Details 6) (USD $)	May 31, 2015	May 31, 2014	May 31, 2013
Summary of stock-based compensation in accordance with authoritative guidance on share based payment awards
Stock based compensation expense	$ 500,000	$ 100,000
Tax benefit	$ 2,000,000	$ 1,800,000	$ 1,500,000

Stockholders' Equity (Details Textual) (USD $)	12 Months Ended					12 Months Ended				12 Months Ended			0 Months Ended	12 Months Ended		12 Months Ended
Stockholders' Equity (Details Textual) (USD $)	May 31, 2015	May 31, 2014	May 31, 2013	Oct. 05, 2011	Feb. 27, 2004	May 31, 2015 Performance Share and Restricted Stock Unit Awards [Member]	May 31, 2014 Performance Share and Restricted Stock Unit Awards [Member]	May 31, 2013 Performance Share and Restricted Stock Unit Awards [Member]	May 31, 2015 Restricted Stock [Member]	May 31, 2015 Performance Shares [Member]	May 31, 2014 Performance Shares [Member]	May 31, 2015 1997 Stock Option Plan [Member]	Oct. 05, 2011 2004 Stock and Incentive Award Plan [Member]	May 31, 2015 2004 Stock and Incentive Award Plan [Member]	May 31, 2015 2004 Stock and Incentive Award Plan [Member] Maximum [Member]	May 31, 2015 Employee Stock Purchase Plan [Member] Employees	May 31, 2014 Employee Stock Purchase Plan [Member]	May 31, 2013 Employee Stock Purchase Plan [Member]	May 31, 2015 Continuing Operations [Member]	May 31, 2014 Continuing Operations [Member]	May 31, 2014 Shareholders' Equity [Member]	May 31, 2013 Shareholders' Equity [Member]	May 31, 2015 Common Stock [Member]	May 31, 2014 Common Stock [Member]	May 31, 2013 Common Stock [Member]	May 31, 2015 Common Stock [Member] 2004 Stock and Incentive Award Plan [Member]	May 31, 2015 Employee Stock Option [Member]
Other Ownership Interests [Line Items]
Employee Service Share-based Compensation, Tax Benefit from Compensation Expense	$ 2,000,000	$ 1,800,000	$ 1,500,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value	$ 14.75	$ 13.23	$ 10.79
Proceeds from Stock Options Exercised	4,300,000	1,300,000	100,000
Authorized capital stock					80,000,000
Shares of common stock	75,000,000	45,000,000			75,000,000
Common stock, par value	$ 0.01	$ 0.01			$ 0.01
Preferred stock, shares authorized	5,000,000	5,000,000			5,000,000
Preferred stock, par value	$ 0.01	$ 0.01			$ 0.01
Authorized the repurchase of common stock				20,000,000
Number of purchased shares	0	0	142,305
Purchase of common stock for treasury			(2,104,000)
Maximum number of shares to be offered																2,000,000
Total number of common stock available to be issued												1,497,674		2,300,000	800,000	1,100,000.0
Share-based Compensation	5,998,000	5,502,000	4,609,000
Options exercisable period												10 years		10 years
Common Stock, Additional Capital Shares Reserved for Future Issuance																800,000										1,000,000
Total number of common stock reserved for issuance														5,750,000
Incentive award plan to increase the minimum number of shares													200,000
Incentive award plan to increase the maximum number of shares													500,000
Percentage of grants to employees vesting	25.00%
Option grants to employees vesting period	4 years
Percentage of grants for consultants vesting	100.00%
Option grants to consultants vesting period	1 year
Subsequent grants for directors vesting	33.33%
Subsequent grants for directors vesting period	3 years
The total intrinsic value of options exercised	1,600,000	1,000,000	100,000
Employee Service Share-based Compensation, Nonvested Awards, Compensation Not yet Recognized, Stock Options	3,471,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Weighted Average Compensation Cost Recognition Period																											3 years
Total fair value of restricted stock awards vesting						2,400,000	1,800,000	1,200,000
Share purchase periods																2
Duration of purchase of shares																6 months
Employee eligible in participating in offering period																6 months
Working schedule of employee to participate in offering period																20 or more hours per week and more than five months in a calendar year
Employees ownership threshold																5.00%
Percentage of fair market value of a share of common stock on the first day of the offering period																85.00%
Percentage of fair market value of a share of common stock on the last day of the offering period																85.00%
Maximum number of shares to be offered under the Stock Purchase Plan																119,001	146,275	123,556					119,001	146,275	123,556
Average price of share issued	$ 11.89	$ 9.30	$ 9.80
Stock based compensation pre tax amount	500,000	100,000
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized									5,600,000	2,200,000	1,800,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value	$ 13.73	$ 14.82								$ 19.83	$ 25.56
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Compensation Cost Probably Recognition Performance Period										3 years
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number	563,101	587,991								200,000	100,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Outstanding, Weighted Average Remaining Contractual Terms										3 years	3 years
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value	$ 4.74	$ 4.10	$ 4.19
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate	1.54%	1.44%	0.62%
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate	31.00%	34.40%	43.91%
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Term	4 years 9 months 3 days	4 years 8 months 25 days	4 years 7 months 13 days
Income tax expense (benefit)	$ (4,731,000)	$ 3,074,000	$ (376,000)																$ 1,300,000	$ 500,000	$ 100,000	$ 1,600,000

Earnings Per Share (Details)	12 Months Ended
Earnings Per Share (Details)	May 31, 2015	May 31, 2014	May 31, 2013
Earnings Per Share [Abstract]
Basic	35,683,139	35,135,689	34,817,279
Effect of dilutive securities	0	304,161	0
Diluted	35,683,139	35,439,850	34,817,279
Securities excluded as their inclusion would be anti-dilutive	2,862,414,000	2,347,426,000	2,904,944,000

- Definition

Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) or earnings per unit (EPU) in the future that were not included in the computation of diluted EPS or EPU because to do so would increase EPS or EPU amounts or decrease loss per share or unit amounts for the period presented.

+ References+ Details

Commitments and Contingencies (Details) (USD $) In Thousands, unless otherwise specified	May 31, 2015
Aggregate of future annual payments under non cancelable operating leases for facilities and equipment [Abstract]
2015	$ 2,192
2016	2,013
2017	1,980
2018	1,962
2019	1,749
Total	$ 9,896

Commitments and Contingencies (Details Textual) (USD $)	0 Months Ended	12 Months Ended			0 Months Ended		12 Months Ended
Commitments and Contingencies (Details Textual) (USD $)	Mar. 18, 2014	May 31, 2015	May 31, 2014	May 31, 2013	Nov. 08, 2012 Biolitec [Member]	Jan. 02, 2008 Biolitec [Member] Lawsuit	May 31, 2015 Cr Bard Inc [Member] Petition
Commitments and Contingencies (Textual) [Abstract]
Aggregate rental costs under operating leases		$ 3,400,000	$ 2,000,000	$ 2,500,000
Number of lawsuits against biolitec previously settled for which seeking defense and indemnification						2
Partial judgment granted					23,200,000
Judgment entered in favor	74,900,000
Number of petitions filed for reexamination of patents							3
Number of rejected patent claims		40 of 41 patent
Total future purchase obligations due through 2018		9,900,000
Purchase obligations after 2018		$ 0

Segments and Geographic Information (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	May 31, 2015	Feb. 28, 2014	Nov. 30, 2013	Aug. 31, 2013	May 31, 2013	Feb. 28, 2013	Nov. 30, 2012	Aug. 31, 2012	May 31, 2015	May 31, 2014	May 31, 2013
Summary of total net sales by product category
Total	$ 90,897	$ 86,597	$ 92,149	$ 87,331	$ 94,060	$ 88,150	$ 88,571	$ 83,644	$ 356,974	$ 354,425	$ 341,916
Peripheral Vascular [Member]
Summary of total net sales by product category
Total									192,833	192,626	179,573
Access [Member]
Summary of total net sales by product category
Total									107,874	106,394	106,690
Oncology/Surgery [Member]
Summary of total net sales by product category
Total									52,090	49,360	47,155
Supply Agreement [Member]
Summary of total net sales by product category
Total									$ 4,177	$ 6,045	$ 8,498

Segments and Geographic Information (Details Textual)	12 Months Ended
Segments and Geographic Information (Details Textual)	May 31, 2015 Segment	May 31, 2014	May 31, 2013
Segments and Geographic Information (Textual) [Abstract]
International sales percentage of total net sales	20.00%	19.00%	20.00%
Number of segment	1
Total assets are located within the United States	99.00%

Restructuring (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended	6 Months Ended	12 Months Ended				6 Months Ended
	May 31, 2015	May 31, 2014 Operational Excellence Program [Member]	May 31, 2015 Operational Excellence Program [Member]	May 31, 2015 Severance [Member] Operational Excellence Program [Member]	May 31, 2014 Severance [Member] Operational Excellence Program [Member]	May 31, 2015 Other Costs [Member] Operational Excellence Program [Member]	May 31, 2014 Minimum [Member] Employees	May 31, 2014 Minimum [Member] Operational Excellence Program [Member]	May 31, 2014 Maximum [Member] Employees	May 31, 2014 Maximum [Member] Operational Excellence Program [Member]	May 31, 2015 Facility Improvements [Member] Operational Excellence Program [Member]
Restructuring Cost and Reserve [Line Items]
Expected future saving								$ 15		$ 18
Expected restructuring costs			4.7								5.4
Expected number of positions eliminated							80,000		100,000
Restructuring costs incurred to date		1.4	2.0	0.5	0.6	0.1
Accelerated depreciation due to restructuring	$ 0.8	$ 0.7	$ 1.5

Quarterly Information Quarterly Information (unaudited) Statement of Immaterial Errors (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	May 31, 2015	Feb. 28, 2014	Nov. 30, 2013	Aug. 31, 2013	May 31, 2013	Feb. 28, 2013	Nov. 30, 2012	Aug. 31, 2012	May 31, 2015	May 31, 2014	May 31, 2013
Cost of sales									$ 180,085	$ 174,757	$ 173,402
Gross profit	45,557	37,851	47,656	45,825	47,410	44,793	44,885	42,580	176,889	179,668	168,514
Operating income									(994)	12,940	6,288
Income before income tax provision									(7,999)	5,740	(1,587)
Income tax expense									(4,731)	3,074	(376)
Net income	(814)	(4,262)	1,338	470	(1,215)	4,515	(261)	(373)	(3,268)	2,666	(1,211)
Income per common share	$ (0.02)	$ (0.12)	$ 0.04	$ 0.01	$ (0.03)	$ 0.13	$ (0.01)	$ (0.01)	$ (0.09)	$ 0.08	$ (0.03)
Income per diluted share	$ (0.02)	$ (0.12)	$ 0.04	$ 0.01	$ (0.03)	$ 0.13	$ (0.01)	$ (0.01)	$ (0.09)	$ 0.08	$ (0.03)
Inventory, net	67,388								67,388	61,234
Income taxes payable	439								439	689
Change in inventories									(6,154)	(5,608)	(1,909)
Accounts payable, accrued and other liabilities									(5,877)	6,658	(9,711)
Net cash provided by operating activities									$ 26,242	$ 24,681	$ 26,652

Quarterly Information (unaudited) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	May 31, 2015	Feb. 28, 2014	Nov. 30, 2013	Aug. 31, 2013	May 31, 2013	Feb. 28, 2013	Nov. 30, 2012	Aug. 31, 2012	May 31, 2015	May 31, 2014	May 31, 2013
Summary of Quarterly Financial Information
Net sales	$ 90,897	$ 86,597	$ 92,149	$ 87,331	$ 94,060	$ 88,150	$ 88,571	$ 83,644	$ 356,974	$ 354,425	$ 341,916
Gross profit	45,557	37,851	47,656	45,825	47,410	44,793	44,885	42,580	176,889	179,668	168,514
Net income	$ (814)	$ (4,262)	$ 1,338	$ 470	$ (1,215)	$ 4,515	$ (261)	$ (373)	$ (3,268)	$ 2,666	$ (1,211)
Earnings per common share
Basic (usd per share)	$ (0.02)	$ (0.12)	$ 0.04	$ 0.01	$ (0.03)	$ 0.13	$ (0.01)	$ (0.01)	$ (0.09)	$ 0.08	$ (0.03)
Diluted (usd per share)	$ (0.02)	$ (0.12)	$ 0.04	$ 0.01	$ (0.03)	$ 0.13	$ (0.01)	$ (0.01)	$ (0.09)	$ 0.08	$ (0.03)

- Definition

The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period.

+ References+ Details

- Definition

The amount of net income (loss) for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period.

+ References+ Details

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References+ Details

Quarterly Information (unaudited) (Details Textual) (USD $)	12 Months Ended			3 Months Ended	9 Months Ended
	May 31, 2015	May 31, 2014	May 31, 2013	May 31, 2015 Restatement Adjustment [Member]	Feb. 28, 2015 Restatement Adjustment [Member]
Business Acquisition [Line Items]
Research and Development Expense	$ 26,931,000	$ 27,486,000	$ 26,319,000		$ 400,000
Operating Leases, Rent Expense	$ 3,400,000	$ 2,000,000	$ 2,500,000	$ 300,000

- Definition

The aggregate costs incurred (1) in a planned search or critical investigation aimed at discovery of new knowledge with the hope that such knowledge will be useful in developing a new product or service, a new process or technique, or in bringing about a significant improvement to an existing product or process; or (2) to translate research findings or other knowledge into a plan or design for a new product or process or for a significant improvement to an existing product or process whether intended for sale or the entity's use, during the reporting period charged to research and development projects, including the costs of developing computer software up to the point in time of achieving technological feasibility, and costs allocated in accounting for a business combination to in-process projects deemed to have no alternative future use.

+ References+ Details

Immaterial Error Corrections (Details) (USD $)	3 Months Ended								12 Months Ended
Immaterial Error Corrections (Details) (USD $)	May 31, 2015	Feb. 28, 2014	Nov. 30, 2013	Aug. 31, 2013	May 31, 2013	Feb. 28, 2013	Nov. 30, 2012	Aug. 31, 2012	May 31, 2015	May 31, 2014	May 31, 2013	May 31, 2012
Cash and Cash Equivalents, at Carrying Value	$ 18,391,000				$ 21,802,000				$ 18,391,000	$ 16,105,000	$ 21,802,000	$ 23,739,000
Accounts Receivable, Net, Current	58,428,000								58,428,000	61,968,000
Net Cash Provided by (Used in) Operating Activities									26,242,000	24,681,000	26,652,000
Revenue, Net	90,897,000	86,597,000	92,149,000	87,331,000	94,060,000	88,150,000	88,571,000	83,644,000	356,974,000	354,425,000	341,916,000
Cost of Goods Sold									180,085,000	174,757,000	173,402,000
Gross profit	45,557,000	37,851,000	47,656,000	45,825,000	47,410,000	44,793,000	44,885,000	42,580,000	176,889,000	179,668,000	168,514,000
Operating Expenses									177,883,000	166,728,000	162,226,000
Operating income (loss)									(994,000)	12,940,000	6,288,000
Other Nonoperating Income (Expense)									(7,005,000)	(7,200,000)	(7,875,000)
Income (loss) before income tax expense (benefit)									(7,999,000)	5,740,000	(1,587,000)
Income Tax Expense (Benefit)									4,731,000	(3,074,000)	376,000
Net income (loss)	(814,000)	(4,262,000)	1,338,000	470,000	(1,215,000)	4,515,000	(261,000)	(373,000)	(3,268,000)	2,666,000	(1,211,000)
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent									(3,567,000)	2,931,000	(1,471,000)
Net Cash Provided by (Used in) Investing Activities									(13,293,000)	(16,448,000)	(22,238,000)
Net Cash Provided by (Used in) Financing Activities									(10,465,000)	(14,016,000)	(6,286,000)
Inventory, net	67,388,000								67,388,000	61,234,000
Prepaid Expense and Other Assets, Current	4,783,000								4,783,000	5,471,000
Assets, Current	155,813,000								155,813,000	151,722,000
Property, Plant and Equipment, Net	54,560,000								54,560,000	66,590,000
Other Assets, Noncurrent	5,288,000								5,288,000	4,447,000
Goodwill	361,252,000				355,637,000				361,252,000	360,473,000	355,637,000
Deferred Tax Assets, Net of Valuation Allowance, Noncurrent	14,904,000								14,904,000	10,403,000
Assets	773,623,000								773,623,000	798,891,000
Accrued Liabilities, Current	18,331,000								18,331,000	17,251,000
Current portion of contingent consideration	9,969,000								9,969,000	10,918,000
Liabilities, Current	61,157,000								61,157,000	66,753,000
Business Combination, Contingent Consideration, Liability, Noncurrent	37,415,000								37,415,000	56,413,000
Liabilities	228,601,000								228,601,000	262,056,000
Additional Paid in Capital, Common Stock	520,101,000								520,101,000	508,354,000
Retained Earnings (Accumulated Deficit)	28,233,000								28,233,000	31,501,000
Stockholders' Equity Attributable to Parent	545,022,000				526,102,000				545,022,000	536,835,000	526,102,000	523,391,000
Intangible Assets, Net (Excluding Goodwill)	181,806,000								181,806,000	205,256,000
Accounts Payable, Current	23,668,000								23,668,000	32,895,000
Depreciation									$ 9,800,000	$ 8,400,000	$ 8,700,000

Valuation and Qualifying Accounts (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	May 31, 2015	May 31, 2014	May 31, 2013
Valuation and Qualifying Accounts
Balance at Beginning of Period	$ 3,267	$ 1,984	$ 2,129
Additions - Charged to costs and expenses	2,313	8,161	4,134
Deductions	(746)	(6,878)	(4,279)
Balance at End of Period	4,834	3,267	1,984
Allowance for deferred tax asset [Member]
Valuation and Qualifying Accounts
Balance at Beginning of Period	1,531	712	1,196
Additions - Charged to costs and expenses	467	819	0
Deductions	(207)	0	(484)
Balance at End of Period	1,791	1,531	712
Allowance for sales returns and doubtful accounts [Member]
Valuation and Qualifying Accounts
Balance at Beginning of Period	1,736	1,272	933
Additions - Charged to costs and expenses	1,846	7,342	4,134
Deductions	(539)	(6,878)	(3,795)
Balance at End of Period	$ 3,043	$ 1,736	$ 1,272

Long-Term Debt (Details) (USD $) In Thousands, unless otherwise specified	May 31, 2015	May 31, 2014
Summary of long-term debt
Less: current maturities	$ (8,750)	$ (5,000)

Stockholders' Equity (Details 5) (USD $) In Thousands, unless otherwise specified	May 31, 2015
Summary of future expense for awards outstanding
Stock options Unrecognized Compensation Cost	$ 3,471

Acquisitions (Details) (USD $) In Thousands, unless otherwise specified	May 31, 2015	May 31, 2014	May 31, 2013
Summary of estimated fair values of the assets acquired and liabilities assumed
Goodwill	$ 361,252	$ 360,473	$ 355,637

Stockholders' Equity (Details 1) (USD $)	12 Months Ended
Stockholders' Equity (Details 1) (USD $)	May 31, 2015	May 31, 2014	May 31, 2013
Summary of weighted average fair value of options granted
Weighted-average fair value of options granted during the year	$ 4.74	$ 4.10	$ 4.19