Document and Entity Information - USD ($)	12 Months Ended
Document and Entity Information - USD ($)	May 31, 2017	Aug. 02, 2017	Nov. 30, 2016
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, 2017
Amendment Flag	false
Document Fiscal Year Focus	2017
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			$ 605,494,808
Entity Common Stock, Shares Outstanding		36,580,575

Consolidated Statements of Operations - USD ($) $ in Thousands	12 Months Ended
	May 31, 2017	May 31, 2016	May 31, 2015
Income Statement [Abstract]
Net sales	$ 349,643	$ 353,890	$ 356,534
Cost of sales (exclusive of intangible amortization)	173,474	179,574	180,738
Gross profit	176,169	174,316	175,796
Operating expenses
Research and development	25,269	25,053	26,594
Sales and marketing	78,819	83,743	82,351
General and administrative	31,406	30,583	30,031
Amortization of intangibles	17,296	17,964	17,966
Change in fair value of contingent consideration	(15,261)	948	(8,096)
Acquisition, restructuring and other items, net	27,510	12,591	26,257
Medical device excise tax	(1,837)	2,416	4,142
Total operating expenses	163,202	173,298	179,245
Operating income (loss)	12,967	1,018	(3,449)
Other (expenses) income
Interest expense, net	(2,839)	(3,385)	(3,193)
Other expense	(281)	(886)	(1,489)
Total other expenses, net	(3,120)	(4,271)	(4,682)
Income (loss) before income tax expense (benefit)	9,847	(3,253)	(8,131)
Income tax expense (benefit)	4,839	40,337	(4,743)
Net income (loss)	$ 5,008	$ (43,590)	$ (3,388)
Earnings per share
Basic (usd per share)	$ 0.14	$ (1.21)	$ (0.09)
Diluted (usd per share)	$ 0.14	$ (1.21)	$ (0.09)
Basic weighted average shares outstanding (in shares)	36,616,859	36,161,383	35,683,139
Diluted weighted average shares outstanding (in shares)	36,959,250	36,161,383	35,683,139

Consolidated Statements Comprehensive Income (Loss) $ in Thousands	12 Months Ended
	May 31, 2017 USD ($)	May 31, 2016 USD ($)	May 31, 2015 USD ($)
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 5,008	$ (43,590)	$ (3,388)
Other comprehensive (loss) income, before tax:
Unrealized gain (loss) on marketable securities	12	(11)	(120)
Stockholders' Equity Attributable to Parent	515,027	507,228	545,099
Unrealized gain (loss) on interest rate swap	0	257	296
Foreign currency translation gain (loss)	(545)	(112)	(264)
Other comprehensive income (loss), before tax	(533)	134	(88)
Income tax benefit (expense) related to items of other comprehensive income (loss)	0	(92)	(64)
Other comprehensive income (loss), net of tax	(533)	42	(152)
Total comprehensive income (loss), net of tax	$ 4,475	$ (43,548)	$ (3,540)

Consolidated Balance Sheets - USD ($) $ in Thousands	May 31, 2017	May 31, 2016
CURRENT ASSETS
Cash and cash equivalents	$ 47,544	$ 32,333
Marketable securities, at fair value	1,215	1,653
Accounts receivable, net of allowances of $2,945 and $4,372, respectively	44,523	52,867
Inventories	54,506	55,370
Prepaid income taxes	336	788
Prepaid expenses and other	5,790	3,243
Total current assets	153,914	146,254
Property, plant and equipment, net	45,234	48,284
Other assets	1,886	3,827
Intangible assets, net	145,675	166,577
Goodwill	361,252	361,252
Total Assets	707,961	726,194
Current Liabilities
Accounts payable	18,087	15,616
Accrued liabilities	38,804	21,942
Current portion of long-term debt	5,000	16,250
Current portion of contingent consideration	9,625	12,919
Total current liabilities	71,516	66,727
Long-term debt, net of current portion	91,320	104,291
Deferred income taxes	26,112	21,684
Contingent consideration, net of current portion	3,136	25,356
Other long-term liabilities	850	908
Total Liabilities	192,934	218,966
Commitments and Contingencies
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 shares authorized; 37,210,091 and 36,420,403 shares issued and 36,840,091 and 36,278,098 shares outstanding at May 31, 2017 and 2016, respectively	367	363
Additional paid-in capital	532,705	525,775
Accumulated deficit	(11,007)	(16,015)
Treasury stock, 370,000 and 142,305 shares, at cost at May 31, 2017 and 2016, respectively	(5,714)	(2,104)
Accumulated other comprehensive loss	(1,324)	(791)
Total Stockholders' Equity	515,027	507,228
Total Liabilities and Stockholders' Equity	$ 707,961	$ 726,194

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	May 31, 2017	May 31, 2016
Statement of Financial Position [Abstract]
Accounts receivable, allowances	$ 2,945	$ 4,372
Preferred stock, par value (usd per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized (shares)	5,000,000	5,000,000
Preferred stock, shares issued (shares)	0	0
Preferred stock, shares outstanding (shares)	0	0
Common stock, par value (usd per share)	$ 0.01	$ 0.01
Shares of common stock (shares)	75,000,000	75,000,000
Common stock, shares issued (shares)	37,210,091	36,420,403
Common stock, shares outstanding (shares)	36,840,091	36,278,098
Treasury stock, shares (shares)	370,000	142,305

Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock	Additional paid in capital	Retained earnings	Accumulated other comprehensive loss	Treasury Stock	Restricted Stock Units	Restricted Stock Units Common Stock	Performance Shares	Performance Shares Common Stock	Performance Shares Additional paid in capital
Beginning Balance at May. 31, 2014	$ 536,885	$ 353	$ 508,354	$ 30,963	$ (681)	$ (2,104)
Beginning Balance, Shares at May. 31, 2014		(35,442,004)				(142,305.000)
Net income	(3,388)			(3,388)
Exercise of stock options	4,338	$ 3	4,335
Exercise of stock options, Shares		341,446
Issuance of restricted shares, net	2	$ 2	0
Issuance of restricted 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
Stock-based compensation	5,998		5,998
Other comprehensive income (loss), net of tax	(152)				(152)
Ending Balance at May. 31, 2015	545,099	$ 360	520,101	27,575	(833)	$ (2,104)
Ending Balance, Shares at May. 31, 2015		(36,043,725)				(142,305.000)
Net income	(43,590)			(43,590)
Exercise of stock options	1,297	$ 1	1,296
Exercise of stock options, Shares		101,040
Issuance of restricted shares, net	(331)	$ 1	(332)
Issuance of restricted shares, net, Shares		137,681
Purchase of common stock under Employee Stock Purchase Plan	1,471	$ 1	1,470
Purchase of common stock under Employee Stock Purchase Plan, Shares		137,957
Stock-based compensation	3,240		3,240
Other comprehensive income (loss), net of tax	42				42
Ending Balance at May. 31, 2016	507,228	$ 363	525,775	(16,015)	(791)	$ (2,104)
Ending Balance, Shares at May. 31, 2016		(36,420,403)				(142,305)
Net income	5,008			5,008
Exercise of stock options	$ 9,865	$ 7	9,858
Exercise of stock options, Shares	826,286	751,062
Issuance of restricted shares, net		$ 1	(587)				$ (586)		$ 0	$ 0	$ 0
Issuance of restricted shares, net, Shares								158,341		23,405
Purchase of common stock under Employee Stock Purchase Plan	$ 1,419	$ 1	1,418
Purchase of common stock under Employee Stock Purchase Plan, Shares		129,185
Stock-based compensation	6,183
Treasury Stock, Retired, Par Value Method, Amount		$ (2)	(9,942)			$ 9,944
Treasury Stock, Shares, Retired		(642,305)				642,305
Treasury Stock, Value, Acquired, Cost Method	(13,557)	$ 3				$ (13,554)
Treasury Stock, Shares, Acquired		(370,000)				(870,000)
Other comprehensive income (loss), net of tax	(533)				(533)
Ending Balance at May. 31, 2017	$ 515,027	$ 367	$ 532,705	$ (11,007)	$ (1,324)	$ (5,714)
Ending Balance, Shares at May. 31, 2017		(37,210,091)				(370,000)

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	May 31, 2017	May 31, 2016	May 31, 2015
Cash flows from operating activities:
Net income (loss)	$ 5,008	$ (43,590)	$ (3,388)
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation and amortization	24,811	28,115	29,861
Deferred income tax provision	4,428	39,983	(5,123)
Stock based compensation	6,183	3,240	5,998
Changes in accounts receivable allowances	(313)	2,377	1,448
Write-off of other assets	(2,685)	0	0
Change in fair value of contingent consideration	(15,261)	948	(8,096)
Loss on impairment/disposal of long-term assets	3,930	806	9,381
Loss on impairment of intangible assets	0	384	6,400
Other	(586)	90	181
Changes in operating assets and liabilities, net of effects of acquisitions:
Accounts receivable	8,479	3,131	2,095
Inventories	687	11,976	(5,648)
Prepaid expenses and other	(3,520)	712	(1,170)
Accounts payable, accrued liabilities and other long-term liabilities	19,214	(2,956)	(6,254)
Net cash provided by operating activities	55,745	45,216	25,685
Cash flows from investing activities:
Additions to property, plant and equipment	(3,001)	(2,326)	(11,383)
Acquisition of intangible assets	0	(3,268)	(1,353)
Acquisition of warrants	0	(2,000)	0
Proceeds from sale or maturity of marketable securities	450	25	0
Net cash used in investing activities	(2,551)	(7,569)	(12,736)
Cash flows from financing activities:
Repayment of long-term debt	(140,381)	(16,250)	(20,000)
Proceeds from issuance of and borrowings on long-term debt	116,471	0	15,000
Proceeds from exercise of stock options and ESPP	10,698	2,437	5,757
Payment of acquisition related contingent consideration	(9,850)	(9,850)	(11,222)
Deferred financing costs on long-term debt	(1,364)	0	0
Repurchase of common stock	13,557	0	0
Net cash used in financing activities	(37,983)	(23,663)	(10,465)
Effect of exchange rate changes on cash and cash equivalents	0	(42)	(198)
Increase in cash and cash equivalents	15,211	13,942	2,286
Cash and cash equivalents
Beginning of year	32,333		18,391
End of year	47,544	32,333
Supplemental disclosure of non-cash investing and financing activities:
Contractual obligations for purchase of fixed assets	26	75	140
Contractual obligations for tax basis adjustment	0	0	779
Cash paid (received) during the year for:
Interest	2,969	3,063	3,151
Income taxes	$ (102)	$ (332)	$ (699)

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

12 Months Ended

May 31, 2017

Accounting Policies [Abstract]

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

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”). The Company designs, manufactures and sells 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. The devices are generally used in minimally invasive, image-guided procedures. Most of the Company's products are intended to be used once and then discarded, or they may be temporarily implanted for short- or long-term use.

Accounting Principles

The consolidated financial statements and accompanying notes have been prepared in conformity with accounting principles generally accepted in the United States of America ("GAAP").

Principles of Consolidation

The consolidated financial statements include the accounts of AngioDynamics and it subsidiaries (all of which are wholly owned). All intercompany balances and transactions have been eliminated.

Use of Estimates

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.

Reclassifications

Certain reclassifications have been made to conform the prior year consolidated financial statements and notes to the current year presentation. These include a reclassification of bad debt expense from Sales and Marketing to General and Administrative. The amount of the reclassification related to fiscal year 2016 is $1.0 million and fiscal year 2015 is $0.9 million. The adoption of ASC Update No. 2015-03 resulted in a reclassification of $0.9 million from other assets to long-term debt in the Company's consolidated balance sheet as of May 31, 2016.

Cash and Cash Equivalents

The Company considers all unrestricted highly liquid investments with an initial maturity of less than three months at the date of purchase to be cash equivalents. The Company maintains 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. The Company holds 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. As of May 31, 2017 and 2016, the Company had $1.2 million and $1.7 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.

Fair Value Instruments

The carrying amount of the Company's cash and cash equivalents, accounts receivable, accounts payable and long-term debt approximates fair value due to the short-term nature or market interest rates of these items. The Company bases the fair value of short-term investments on quoted market prices or other relevant information generated by market transactions involving identical or comparable assets. The Company measures and records derivative financial instruments at fair value. See Note 3 for further discussion of financial instruments that are carried at fair value on a recurring and nonrecurring basis.

Accounts Receivable

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

The Company evaluates property, plant and equipment for impairment periodically to determine if changes in circumstances or the occurrence of events suggest the carrying value of the asset or asset group may not be 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 IP R&D are amortized over their estimated useful lives, which range between two and eighteen 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. The Company periodically reviews the estimated useful lives of intangible assets and review such assets for impairment whenever events or changes in circumstances indicate that the carrying value of the asset or asset group is not recoverable. The Company determines the fair value of the reporting unit based on the market valuation approach or the income approach. If an intangible asset or asset group 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 IP R&D has an indefinite life and is not amortized until completion of the development of the project, at which time the IP R&D becomes an amortizable asset. If the related project is not completed in a timely manner or the project is terminated or abandoned, the Company may have an impairment related to the IP R&D, calculated as the excess of the asset’s carrying value over its fair value.

The Company's policy defines IP R&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 IP R&D requires us to make significant estimates. The amount of the purchase price allocated to IP R&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 is the amount by which the cost of acquired net assets in a business combination exceeded the fair value of net identifiable assets on the date of purchase. 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.

For goodwill, the impairment test requires a comparison of the estimated fair value of the reporting unit to which the goodwill is assigned to carrying value of the assets and liabilities of that reporting unit. The determination of reporting units also requires management judgment. The Company considers whether a reporting unit exists within a reportable segment based on the availability of discrete financial information. If carrying value of the 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. The Company utilizes either discounted cash flow models or other valuation models, such as comparative transactions and market multiples, to determine the fair value of our reporting unit. The Company makes assumptions about future cash flows, future operating plans, discount rates, comparable companies, market multiples, purchase price premiums and other factors in those models. Different assumptions and judgment determinations could yield different conclusions that would result in an impairment charge to income in the period that such change or determination was made.

Contingent Consideration

The fair value of the liability for contingent consideration recorded on the acquisition date for a business combination is based on probability weighted estimated cash flow streams, discounted back to present value using a discount rate determined in accordance with accepted valuation methods and reflective of the risk associated with the estimated cash flow streams. The liability for contingent consideration is remeasured to fair value at each reporting period with changes recorded in earnings until the contingency is resolved.

Revenue Recognition

The Company recognizes 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. The Company recognizes 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. The Company negotiates 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 the Company 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.

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

The Company calculates income tax expense for each jurisdiction in which it operates. 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. The Company periodically evaluates deferred tax assets, capital loss carryforwards and tax credit carryforwards to determine their recoverability based primarily on the Company's ability to generate future taxable income and capital gains. Where it is more-likely-than-not these will not be recovered, the Company estimates a valuation allowance and records a corresponding additional tax expense in the consolidated statement of operations.

The Company recognizes and measures uncertain tax positions taken or expected to be taken in a tax return utilizing a two-step approach. The Company first determines if the weight of available evidence indicates that it is more likely than not that the tax position will be sustained on audit, including resolution of any related appeals or litigation processes. The second step is that the Company measures the tax benefit as the largest amount that is more likely than not to be realized upon ultimate settlement. The Company recognizes interest and penalties related to uncertain tax positions in the provision for income taxes on the consolidated statements of operations.

Warranty Costs

The Company makes periodic provisions for expected warranty costs. Historically, warranty costs have been insignificant.

Stock Based Compensation

Stock-based compensation expense reflects the fair value of stock-based awards measured at the grant date and recognized over the relevant service period. The Company estimates the fair value of each stock-based award on the measurement date using either the current market price of the stock, the Black-Scholes option valuation model, or the Monte Carlo Simulation valuation model. The Black-Scholes and Monte Carlo Simulation valuation models incorporate assumptions as to stock price volatility, the expected life of options or restricted stock units, a risk-free interest rate and dividend yield. The Company recognizes stock-based compensation expense related to options, restricted stock units and market based performance stock units on a straight-line basis over the service period of the award, which is generally 4 years for options and restricted stock units and 3 years for market based performance stock units.

Foreign Currency Translation

The functional currency of most of the Company's foreign subsidiaries is the local currency in which the subsidiary operates. For foreign operations where the local currency is considered to be the functional currency, the Company translates assets and liabilities into U.S. dollars at the exchange rate on the balance sheet date. The Company translates income and expense items at average rates of exchange prevailing during each period. The Company accumulates translation adjustments in accumulated other comprehensive loss, a component of stockholders’ equity.

For foreign operations where the U.S. dollar is considered to be the functional currency, the Company remeasures monetary assets and liabilities into U.S. dollars at the exchange rate on the balance sheet date and non-monetary assets and liabilities are remeasured into U.S. dollars at historical exchange rates. The Company translates income and expense items at average rates of exchange prevailing during each period. The Company recognizes remeasurement adjustments as a component of other expense in the consolidated statements of operations.

Transaction gains or losses that arise from exchange rate fluctuations on transactions denominated in a currency other than the functional currency are included in other expense in the statements of operations as incurred.

Derivative Financial Instruments

The Company is exposed to market risks, including changes in foreign currency and interest rates. The Company periodically enters into certain derivative financial instruments to hedge the underlying economic exposure.

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).

Contingencies

The Company is subject to various legal proceedings that arise in the ordinary course of business, including patent infringement and product liability matters. The Company records accruals for contingencies when it is probable the liability has been incurred and the amount can be reasonably estimated. Legal fees are expensed as incurred. Insurance recoveries related to potential claims are recognized up to the amount of the recorded liability when coverage is confirmed and the estimated recoveries are probable of payment. These recoveries are not netted against the related liabilities for financial statement presentation.

Recently Issued Accounting Pronouncements - Adopted

In April 2015, the Financial Accounting Standards Board ("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. This was adopted in the first quarter of fiscal 2017 and the Company reclassified $0.9 million from other assets to long-term debt, net in the balance sheet as of May 31, 2016.

Recently Issued Accounting Pronouncements - Not Yet Applicable or Adopted

In May 2014, the 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 2019, 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 evaluating the impact of ASU 2014-09 on its consolidated financial statements.

In July 2015, the FASB issued ASC Update No. 2015-11, Inventory (Topic 330): Simplifying the Measurement of Inventory. Update No. 2015-11 more closely aligns the measurement of inventory in U.S. GAAP with the measurement of inventory in International Financial Reporting Standards by requiring companies using the first-in, first-out and average costs methods to measure inventory using the lower of cost and net realizable value, where net realizable value is the estimated selling prices in the ordinary course of business, less reasonably predictable costs of completion, disposal, and transportation. Update No. 2015-11 is effective for annual reporting periods beginning after December 15, 2016 and interim periods within those fiscal years. Update No. 2015-11 should be applied prospectively with earlier application permitted as of the beginning of an interim or annual reporting period. The adoption of Update No. 2015-11 is not expected to have a material impact on the Company's financial position or results of operations.

In February 2016, the FASB issued ASU 2016-02, Leases (Topic 842). ASU 2016-02 increases transparency and comparability among organizations by recognizing lease assets and liabilities on the balance sheet and disclosing key information about leasing arrangements. For leases with a term or twelve months or less, a lessee is permitted to make an accounting policy election by class of underlying asset not to recognize lease assets and liabilities. ASU 2016-02 is effective for fiscal years beginning after December 15, 2018 and early application is permitted. The Company is currently in the process of evaluating the impact of ASU 2016-02 on its consolidated financial statements.

In March 2016, the FASB issued ASU 2016-09, Compensation - Stock Based Compensation (Topic 718: Improvements to Employee Share-Based Payment Accounting). ASU 2016-09 simplifies and improves various aspects of ASC 718 for share-based payments, including income tax items and the classification of these items on the statement of cash flows. ASU 2016-09 is effective for annual periods beginning after December 31, 2016 and early application is permitted. The Company is currently in the process of evaluating the impact of ASU 2016-09 on its consolidated financial statements.

In August 2016, the FASB issued ASU No. 2016-15, Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments (ASU 2016-15). ASU 2016-15 identifies how certain cash receipts and cash payments are presented and classified in the Statement of Cash Flows under Topic 230. ASU 2016-15 is effective for the Company for fiscal years beginning after December 15, 2017, and interim periods within those fiscal years. ASU 2016-15 should be applied retrospectively and early adoption is permitted, including adoption in an interim period. The Company is currently in the process of evaluating the impact of ASU 2016-15 on its consolidated financial statements.

In January 2017, the FASB issued ASU 2017-04, Intangibles - Goodwill and Other (Topic 350), which simplifies the subsequent measurement of goodwill by eliminating steps from the goodwill impairment test. ASU 2017-04 should be adopted for annual or interim goodwill impairment tests in fiscal years beginning after December 15, 2019. ASU 2017-04 should be applied prospectively and early adoptions is permitted, including adoption in an interim period. The Company is currently evaluating the impact of ASU 2017-04 on its consolidated financial statements.

Other Assets	12 Months Ended
Other Assets	May 31, 2017
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Other Assets	OTHER ASSETS In 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. The Company made an initial $2.0 million purchase of non-transferable warrants in a subsidiary of EmboMedics which become exercisable upon a change of control of EmboMedics. The Company did not have significant influence, or control of the subsidiary. This initial investment was recorded at cost and the Company reviewed for impairment at each balance sheet date. In the second quarter of fiscal year 2017, the Company decided to terminate its agreements with EmboMedics. The termination of these agreements resulted in a write-off of the initial $2.0 million investment in EmboMedics which is included in acquisition, restructuring and other items, net on the consolidated statements of operations.

Fair Value of Financial Instruments

12 Months Ended

May 31, 2017

Fair Value Disclosures [Abstract]

Fair Value of Financial Instruments

The following tables provide information by level for assets and liabilities that are measured at fair value on a recurring basis:



	Fair Value Measurements using inputs considered as:
(in thousands)	Level 1		Level 2		Level 3		Fair Value at May 31, 2017
Financial Assets
Marketable securities	$	—	$	—	$	1,215	$	1,215
Total Financial Assets	$	—	$	—	$	1,215	$	1,215
Financial Liabilities
Contingent liability for acquisition earn outs	$	—	$	—	$	12,761	$	12,761
Total Financial Liabilities	$	—	$	—	$	12,761	$	12,761



	Fair Value Measurements using inputs considered as:
(in thousands)	Level 1		Level 2		Level 3		Fair Value at May 31, 2016
Financial Assets
Marketable securities	$	—	$	—	$	1,653	$	1,653
Total Financial Assets	$	—	$	—	$	1,653	$	1,653
Financial Liabilities
Contingent liability for acquisition earn outs	$	—	$	—	$	38,275	$	38,275
Total Financial Liabilities	$	—	$	—	$	38,275	$	38,275

There were no transfers in and out of Level 1, 2 and 3 measurements for the years ended May 31, 2017 and 2016.

The table below presents the changes in fair value components of Level 3 instruments in the year ended May 31, 2017 (in thousands of dollars):



	Financial Assets			Financial Liabilities
(in thousands)	Fair Value Measurements Using Significant Unobservable Inputs (Level 3)			Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
Balance at May 31, 2016	$	1,653		$	38,275
Change in fair value of contingent consideration, net (1)	—			(15,261		)
Currency (gain) loss from remeasurement	—			(153		)
Fair market value adjustments	12			—
Sale of securities	(450		)	—
Contingent consideration payments	—			(10,100		)
Balance at May 31, 2017	$	1,215		$	12,761

The Company made the decision to discontinue its investment in the TiLo product that was acquired in August 2013 as part of the Clinical Devices acquisition. This decision resulted in the write-off of the acquired in-process research and development (IPR&D) of $3.6 million along with a $3.1 million gain from the reduction in the fair value of contingent consideration liability associated with future milestones that will no longer be met. The write-off of the IPR&D is included in acquisition, restructuring and other, net on the consolidated statement of operations.

The Company revised the sales projections for the AngioVac product as a result of reviews performed by executive management across all products. The adjustments to the sales projections resulted in a $13.4 million gain from the reduction in the fair value of the contingent liability that is based on lower projected sales volume over the contractual earn out period.

The Company decided to terminate its agreement with EmboMedics which resulted in a $2.0 million write-off of our investment in EmboMedics (Note 2).

The table below presents the changes in fair value components of Level 3 instruments in the year ended May 31, 2016 (in thousands of dollars):



	Financial Assets			Financial Liabilities
(in thousands)	Fair Value Measurements Using Significant Unobservable Inputs (Level 3)			Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
Balance at May 31, 2015	$	1,689		$	47,384
Change in fair value of contingent consideration (1)	—			948
Currency (gain) loss from remeasurement	—			43
Fair market value adjustments	(36		)	—
Contingent consideration payments	—			(10,100		)
Balance at May 31, 2016	$	1,653		$	38,275

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

Marketable Securities

Marketable securities consist solely of an auction rate security. Assumptions associated with the auction rate security include 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.

Contingent Liability for Acquisition Earn Outs

Certain 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.

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 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, 2017:



(in thousands)	Fair value at May 31, 2017		Valuation Technique	Unobservable Input	Range
Revenue based payments	$	12,761	Discounted cash flow	Discount rate Probability of payment Projected fiscal year of payment	4% 100% 2018 - 2022

At May 31, 2017, the estimated potential amount of undiscounted future contingent consideration that the Company expects to pay as a result of all completed acquisitions is approximately $13.1 million, which represents the remaining contractual minimum payments.

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References + Details

Marketable Securities

12 Months Ended

May 31, 2017

Investments, Debt and Equity Securities [Abstract]

MARKETABLE SECURITIES AND INVESTMENTS

MARKETABLE SECURITIES

As of May 31, 2017, 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	$	1,350	$	—	$	(135	)	$	1,215
	$	1,350	$	—	$	(135	)	$	1,215

As of May 31, 2016, 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	$	1,800	$	—	$	(147	)	$	1,653
	$	1,800	$	—	$	(147	)	$	1,653

The amortized cost and fair value of marketable securities as of May 31, 2017, 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, 2017:
Due in one year or less	$	—	$	—
Due after one through five years	—		—
Due after five through twenty years (1)	1,350		1,215
	$	1,350	$	1,215

(1) This auction rate security represents investments available for current operations and are classified as current in the consolidated balance sheets.

Inventories

12 Months Ended

May 31, 2017

Inventory Disclosure [Abstract]

INVENTORIES

As of May 31, 2017 and 2016, inventories consisted of the following:



	May 31, 2017		May 31, 2016
(in thousands)
Raw materials	$	17,563	$	21,669
Work in process	12,602		10,700
Finished goods	24,341		23,001
Total	$	54,506	$	55,370

The Company periodically reviews for both obsolescence and loss of value. The Company makes assumptions about the future demand for and market value of the inventory. Based on these assumptions, the Company estimates the amount of obsolete, expiring and slow moving inventory. The total inventory reserve at May 31, 2017 and 2016 was $7.3 million and $12.6 million, respectively. Of the $7.3 million, $2.4 million relates to the inventory reserve for Acculis inventory as a result of the recall (Note 10). Of the $12.6 million in the prior year, $5.8 million relates to the reserve of Celerity inventory on-hand at May 31, 2016.

Property, Plant and Equipment, Net

12 Months Ended

May 31, 2017

Property, Plant and Equipment [Abstract]

PROPERTY, PLANT AND EQUIPMENT, AT COST

PROPERTY, PLANT AND EQUIPMENT, NET

As of May 31, 2017 and 2016, property, plant and equipment are summarized as follows:



	May 31, 2017			May 31, 2016
(in thousands)
Building and building improvements	$	40,597		$	39,585
Machinery and equipment	25,434			24,078
Computer software and equipment	25,668			24,691
Construction in progress	1,464			1,743
	93,163			90,097
Less accumulated depreciation and amortization	(49,652		)	(43,536		)
	43,511			46,561
Land and land improvements	1,723			1,723
	$	45,234		$	48,284

Depreciation expense for fiscal 2017, 2016 and 2015 was $6.0 million, $8.2 million and $9.8 million, respectively.

Goodwill and Intangible Assets

12 Months Ended

May 31, 2017

Goodwill and Intangible Assets Disclosure [Abstract]

GOODWILL AND INTANGIBLE ASSETS

Intangible assets other than goodwill are amortized over their estimated useful lives on either a straight-line basis or proportionately to the benefit being realized. Useful lives range from two to eighteen years. The Company periodically reviews the estimated useful lives of intangible assets and review such assets or asset groups for impairment whenever events or changes in circumstances indicate that the carrying value of the assets or asset groups may not be recoverable. If an intangible asset or asset group 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.

Goodwill is not amortized, but rather, is 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.

The Company's annual testing for impairment of goodwill was completed as of December 31, 2016. The Company operates as a single operating segment with one reporting unit and consequently evaluates goodwill for impairment based on an evaluation of the fair value of the Company as a whole. The Company determines the fair value of the reporting unit based on the market valuation approach and concluded that it was not more-likely-than-not that the fair value of the Company's reporting unit was less than its carrying value.

Even though the Company determined that there was no goodwill impairment as of December 31, 2016, the future occurrence of a potential indicator of impairment, such as a significant adverse change in legal, regulatory, business or economic conditions 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, 2017. The Company continued to assess for potential impairment through May 31, 2017 and noted no events that would be considered a triggering event. There were no adjustments to goodwill for the years ended May 31, 2017 and 2016.

As of May 31, 2017 and 2016, intangible assets consisted of the following:



	May 31, 2017
	Gross carrying value		Accumulated amortization			Net carrying value
(in thousands)
Product technologies	$	147,172	$	(59,696	)	$	87,476
Customer relationships	56,375		(19,194		)	37,181
Trademarks	28,400		(9,069		)	19,331
Licenses	4,487		(3,821		)	666
Distributor relationships	1,250		(229		)	1,021
	$	237,684	$	(92,009	)	$	145,675



	May 31, 2016
	Gross carrying value		Accumulated amortization			Net carrying value
(in thousands)
Product technologies	$	148,387	$	(51,313	)	$	97,074
Customer relationships	88,389		(47,133		)	41,256
Trademarks	28,470		(6,242		)	22,228
Licenses	7,931		(6,716		)	1,215
Distributor relationships	2,150		(946		)	1,204
In process R&D	3,600		—			3,600
	$	278,927	$	(112,350	)	$	166,577

Amortization expense was $17.3 million, $18.0 million and $18.0 million for fiscal years 2017, 2016 and 2015, respectively.

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



(in thousands)
2018	$	16,500
2019	16,132
2020	14,578
2021	13,627
2022	12,952
2023 and thereafter	71,886
	$	145,675

- 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, 2017

Income Tax Disclosure [Abstract]

INCOME TAXES

TAXES

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



	2017		2016			2015
(in thousands)
Income (loss) before tax expense:
US	$	8,825	$	(4,444	)	$	(8,965	)
Non-US	1,022		1,191			834
	$	9,847	$	(3,253	)	$	(8,131	)

Income tax expense (benefit) is comprised of the following:



	2017		2016		2015
(in thousands)
Current
Federal	$	—	$	34	$	(242	)
State and local	141		103		205
Non U.S.	270		217		417
	411		354		380
Deferred	4,428		39,983		(5,123		)
Income tax expense (benefit)	$	4,839	$	40,337	$	(4,743	)

In the fiscal years 2017 and 2016 income tax expense, the Company recorded tax expense of $4.8 million and $40.3 million, respectively, primarily driven by the impact of recording a deferred tax liability related to the amortization of intangibles, for tax purposes, that have an indefinite reversal period and cannot be used to support the deferred tax assets in fiscal 2017 and recording a valuation allowance of $40.4 million on the U.S. deferred tax assets in fiscal 2016.

In the fiscal year 2015 income tax benefit, the Company recorded a tax benefit of $4.7 million, primarily driven by a benefit of the $9.2 million nontaxable adjustment to the contingent liabilities related to Vortex Medical and Clinical Devices, and a seven month benefit from the R&D tax credit that expired on December 31, 2014, offset by non-deductible interest expense related to contingent payments, true-ups of our fiscal year 2014 US income tax returns and the impact of the elimination of the ASC 718 APIC pool.

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



	May 31, 2017			May 31, 2016
(in thousands)
Deferred tax assets
Net operating loss carryforward	$	55,975		$	52,593
Stock-based compensation	2,653			4,135
Federal and state R&D tax credit carryforward	2,548			2,145
Inventories	2,407			4,535
Expenses incurred not currently deductible	6,522			3,018
Accrued liabilities	1,289			339
Gross deferred tax asset	71,394			66,765
Deferred tax liabilities
Excess tax over book depreciation and amortization	49,158			46,240
	49,158			46,240
Valuation Allowance	(48,348		)	(42,209		)
Net deferred tax liability	$	(26,112	)	$	(21,684	)

The Company's Federal net operating loss carryforwards as of May 31, 2017 after considering IRC Section 382 limitations are $161.6 million. The expiration of the Federal net operating loss carryforwards are as follows: $29.8 million between 2017 and 2023 and $131.8 million between 2027 and 2037.

The Company's state net operating loss carryforwards as of May 31, 2017 after considering remaining IRC Section 382 limitations are $32.7 million which expire in various years from 2017 to 2037.

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, 2017 and 2016 that arose directly from tax deductions related to equity compensation greater than compensation recognized for financial reporting. Equity will be increased by $0.6 million if and when such excess tax benefits are ultimately realized.

A valuation allowance is provided if based upon the weight of available evidence, it is more likely than not that some or all of the deferred tax assets will not be realized. After careful consideration and weighing of all the available positive and negative evidence, the weight given to the three year cumulative loss and lack of a recent history of core earnings was difficult to overcome and a full valuation allowance related to the U.S. deferred tax assets was established in the period ending May 31, 2016. Management considered all available positive and negative evidence at May 31, 2017, and considering the cumulative loss in the U.S. over the three year period, determined that the valuation allowance is still required. Management will continue to reevaluate the positive and negative evidence at each reporting period and if future results as projected in the U.S. and the Company's tax planning strategies are favorable, the valuation allowance may be removed, which could have a favorable material impact on the Company's results of operations in the period in which it is recorded.

The net deferred tax liability as of May 31, 2017 and 2016 relates to tax amortization of intangibles that have an indefinite reversal period for book purposes and cannot be used to support the deferred tax asset.

The Company's consolidated income tax expense has differed from the amount that would be provided by applying the U.S. Federal statutory income tax rate to the Company's income before income taxes for the following reasons:



	For the year ended May 31,
	2017			2016			2015
(in thousands)
Income tax expense (benefit) at statutory tax rate of 35%	$	3,447		$	(1,139	)	$	(2,845	)
Effect of graduated tax rates	(98		)	33			81
State income taxes, net of Federal tax benefit	(22		)	(215		)	(21		)
Impact of Non-US operations	403			(162		)	133
Research and development tax credit	(403		)	(499		)	(604		)
Meals and entertainment	266			329			—
Non-deductible interest on contingent payments	174			262			265
Non-taxable gain on revaluation of contingent consideration liability	(5,576		)	(170		)	(3,102		)
Tax law changes	—			—			(454		)
Change in valuation allowance	6,139			40,685			—
Effect of elimination of stock compensation APIC pool	1,380			739			1,253
IPR&D intangible write-off	(1,224		)	—			—
Other nondeductible expenses	219			207			498
Over (under) accrual of prior year Federal and State taxes	(3		)	356			38
Other	137			(89		)	15
Income tax expense (benefit)	$	4,839		$	40,337		$	(4,743	)

The following table provides a reconciliation of the beginning and ending amount of unrecognized tax benefits:



	For the year ended May 31,
	2017		2016		2015
(in thousands)
Unrecognized tax benefits balance at June 1	$	899	$	—	$	—
Increase in gross amounts of tax positions related to prior years	—		899		—
Unrecognized tax benefits balance at May 31	$	899	$	899	$	—

The table above includes unrecognized tax benefits associated with the calculation of limitations placed on the utilization of tax attributes related to an acquired company. If recognized, $0.1 million of the balance of unrecognized tax benefits as of May 31, 2017 would affect the effective tax rate and the balance of $0.8 million would result in adjustments to other tax accounts.

The Company recognizes interest and penalties related to unrecognized tax benefits as a component of income tax expense. There are no accrued interest and penalties recognized in the consolidated balance sheet as of May 31, 2017 and May 31, 2016.

The Company files income tax returns in the U.S. federal jurisdiction and various state and foreign jurisdictions. In the normal course of business the Company is subject to examination by taxing authorities throughout the world. Fiscal years 2014 through 2017 remain open to examination by the various tax authorities.

The Company does 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 $5.3 million, and are intended to remain indefinitely invested in foreign operations. Accordingly, no taxes have been provided on these earnings as of May 31, 2017. 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.

Accrued Liabilities

12 Months Ended

May 31, 2017

Payables and Accruals [Abstract]

ACCRUED LIABILITIES

As of May 31, 2017 and 2016, accrued liabilities consist of the following:



	May 31, 2017		May 31, 2016
(in thousands)
Payroll and related expenses	$	11,383	$	9,414
Royalties	2,885		2,489
Accrued severance	2,075		1,524
Sales and franchise taxes	856		565
Outside services	1,622		2,063
Litigation matters (Note 15)	12,500		—
Acculis recall liability	2,563		—
Other	4,920		5,887
Total	$	38,804	$	21,942

In the fourth quarter of fiscal year 2017, the Company issued a voluntary recall of its Acculis probes that were sold over the past two years. As a result of this voluntary recall, the Company decided to also do a voluntary market withdrawal of its Acculis capital systems and discontinue selling the product. The voluntary recall resulted in a deferral of revenue of $2.6 million and an increase of $2.6 million in inventory and hardware asset reserves. The total impact to income before taxes of the recall was $4.5 million.

Long-Term Debt

12 Months Ended

May 31, 2017

Debt Disclosure [Abstract]

LONG-TERM DEBT

On November 7, 2016, the Company entered into a 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 JPMorgan Chase Bank, N.A., Merrill Lynch, Pierce, Fenner & Smith Incorporated and Keybank National Association as joint bookrunners and joint lead arrangers.

The Credit Agreement provides for a $100.0 million senior secured term loan facility and a $150.0 million senior secured revolving credit facility, which includes up to a $20.0 million sublimit for letters of credit and a $5.0 million sublimit for swingline loans.

On November 7, 2016, the Company borrowed $100.0 million under the Term Loan and approximately $16.5 million under the Revolving Facility to repay the balance of $116.5 million under the former credit agreement. In February 2017 the revolver was paid off in full. As of May 31, 2017 and 2016 the carrying value of long-term debt approximates its fair market value.

The proceeds of the Revolving Facility may be used for general corporate purposes of the Company and its subsidiaries. The Facilities have a five year maturity. Interest on both the Term Loan and Revolving Facility are based on a base rate or Eurodollar rate plus an applicable margin which increases as total leverage ratio increases, with the base rate and Eurodollar rate having ranges of 0.50% to 1.25% and 1.50% to 2.25% respectively. In case of default, the interest rate may be increased by 2.0%. The Revolving Facility carries a commitment fee of 0.20% to 0.35% per annum on the unused portion. The interest rate on the Term Loan at May 31, 2017 was 2.55%.

The Company's obligations under the Facilities are unconditionally guaranteed, jointly and severally, by the Company's material direct and indirect domestic subsidiaries (the “Guarantors”). All obligations of the Company and the Guarantors under the Facilities are secured by first priority security interests in substantially all of the assets of the Company and the Guarantors.

The Credit Agreement includes customary representations, warranties and covenants, and acceleration, indemnity and events of default provisions, including, among other things, two quarterly financial covenants as follows:

•maximum leverage ratio of consolidated total indebtedness* to consolidated EBITDA* of not greater than 3.50 to 1.00 (during certain periods following material acquisitions shall be increased to 3.75 to 1.00).

• fixed charge coverage ratio of consolidated EBITDA minus consolidated capital expenditures to consolidated interest expense paid or payable in cash plus scheduled principal payments in respect of indebtedness under the Credit Agreement of not less than 1.25 to 1.00.

* The definitions of consolidated total indebtedness and consolidated EBITDA are maintained in the credit agreement included as an exhibit to Form 8-k filed on November 10, 2016.

The Company was in compliance with both covenants as of May 31, 2017.

The Company's maturities of principal obligations under the credit agreement are as follows, as of May 31, 2017:



(in thousands)
2018	$	5,000
2019	5,000
2020	7,500
2021	11,250
2022	68,750
Total term loan	97,500
Revolving facility	—
Total debt	97,500
Less: Unamortized debt issuance costs	(1,180		)
Total	96,320
Less: Current portion of long-term debt	(5,000		)
Total long-term debt, net of current portion	$	91,320

Stockholders' Equity

12 Months Ended

May 31, 2017

Equity [Abstract]

STOCKHOLDERS' EQUITY

STOCKHOLDERS’ EQUITY

Capitalization

On October 29, 2014, the Board of Directors approved the 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 the Company liquidates, dissolves, or winds 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 the Company may designate in the future.

The 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 the Company's stockholders.

Stock Options

2004 Stock and Incentive Award Plan

The 2004 Stock and Incentive Award Plan (the “2004 Plan”) provides for the grant of incentive options to employees and for the grant of non-statutory stock options, restricted stock, stock appreciation rights, performance units, performance shares and other incentive awards to employees, directors and other service providers. A total of 7,000,000 shares of 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 common stock on the date of grant. The term of an incentive stock option may not exceed ten years.

On October 25, 2016, the Company amended the 2004 Stock and Incentive Award Plan to increased the shares of common stock reserved for issuance by 250,000 shares.

As of May 31, 2017, there remained approximately 2.4 million shares available for granting under the 2004 Plan.

The following table summarizes information about stock option activity for the fiscal year ended May 31, 2017.



	2017
	Shares		Weighted- average exercise price		Weighted average remaining contractual life	Aggregate intrinsic value (in thousands)
Outstanding at beginning of year	2,281,618		$	14.45
Granted	667,691		$	16.83
Exercised	(826,286	)	$	13.45
Forfeited	(342,924	)	$	16.03
Expired	(112,656	)	$	19.08
Outstanding at end of year	1,667,443		$	15.01	4.66	$	1,513
Options exercisable at year-end	659,463		$	14.26	2.88	$	913
Options expected to vest in future periods	884,906		$	15.50	5.83	$	527

Stock options are granted at exercise prices equal to the quoted market price of 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.

The Company measures 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 May 31, 2017, 2016 and 2015 was $4.70, $4.16, and $4.74, respectively. The following assumptions were used in arriving at the fair value of options granted during 2017, 2016 and 2015, respectively: risk-free interest rates of 1.30%, 1.48% and 1.54%; expected volatility of 31%, 31%, and 31%; and expected lives of 4.80 years, 4.81 years, and 4.76 years. The Company does not declare dividends therefore a dividend yield of zero was used for the years ended May 31, 2017, 2016 and 2015. 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 the Company's stock. The expected option lives are based on historical experience of employee exercise behavior.

The total intrinsic value of options exercised during the years ended May 31, 2017, 2016 and 2015 was $2.8 million, $0.1 million, and $1.6 million, respectively. As of May 31, 2017, there was $3.7 million of total unrecognized compensation cost related to non-vested options, which is expected to be recognized over a weighted average period of 3 years.

Cash received from option exercises during 2017, 2016 and 2015 was $9.9 million, $1.3 million and $4.3 million, respectively. The tax benefit realized from stock options exercised during the years ended May 31, 2016 and 2015 were $0.1 million and $0.5 million, respectively. Due to the valuation allowance there was no tax benefit realized from stock option exercises during the year ended May 31, 2017.

Performance Share and Restricted Stock Unit Awards

The Company grants restricted stock units to certain employees under the 2004 Plan which give the recipients the right to receive shares of Company 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 the Company.

The following table summarizes information about restricted stock unit activity for the year ended May 31, 2017.



			Weighted Average Grant-Date Fair Value
Non-vested at beginning of year	549,777		$	14.62
Granted	255,032		$	16.54
Vested	(182,320	)	$	16.10
Canceled	(183,192	)	$	15.95
Non-vested at end of year	439,297		$	15.55

The fair value of each restricted stock unit is the market price of Company stock on the date of grant. The weighted average grant date fair value of restricted stock units granted during the years ended May 31, 2017, 2016 and 2015 was $16.54, $15.21 and $14.75, respectively. The total intrinsic value of restricted stock units (meaning the fair value of the units on the date of vest) vesting during the years ended May 31, 2017, 2016 and 2015 was $2.9 million, $2.5 million, and $2.4 million, respectively. As of May 31, 2017, there was $4.9 million of total unrecognized compensation cost related to non-vested restricted stock awards, which is expected to be recognized over a weighted average period of 3 years.

The Company grants performance share awards to certain employees under the 2004 Plan which gives the recipients the right to receive shares of Company 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 relative total shareholder return ("TSR"), 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 the Company.

The following table summarizes information about performance unit award activity for the year ended May 31, 2017.



	Performance Unit Awards		Weighted Average Grant-Date Fair Value
Non-vested at beginning of year	435,892		$	19.16
Granted	93,400		$	22.61
Vested	(37,184	)	$	14.48
Canceled	(130,944	)	$	21.54
Non-vested at end of year	361,164		$	18.54

During fiscal years 2017, 2016 and 2015, we granted performance unit awards that include a three-year market condition. Vesting of the performance unit awards is based on the Company's level of attainment of specified total shareholder return ("TSR") targets relative to the percentage appreciation of a specified index of companies for the respective three-year periods. It is also subject to the continued employment of the grantees. In order to estimate the fair value of such awards, we used a Monte Carlo Simulation valuation model on the date of the grant. For the years ended May 31, 2017, 2016 and 2015, the weighted average grant date fair market value for new grants was $22.61, $18.07 and $19.83, respectively. Compensation cost is recognized over the performance period which is typically three years. As of May 31, 2017, 0.4 million performance share units with a weighted average remaining contractual term of 3 years and $4.2 million of unrecognized compensation cost were outstanding.

Compensation Expense

The following tables represents the break out of share-based compensation included in the Company's consolidated statement of operations.



	For the year ended May 31,
(in thousands)	2017			2016			2015
Cost of sales	$	299		$	172		$	143
Research and development	314			349			229
Sales and marketing	1,762			1,489			1,685
General and administrative	4,026			2,291			3,941
Acquisition, restructuring and other items, net	(218		)	(1,061		)	—
	$	6,183		$	3,240		$	5,998

The income tax benefit on the compensation expense recognized for all share-based compensation arrangements was $2.2 million, $1.0 million and $2.0 million for the years ended May 31, 2017, 2016 and 2015, respectively. The income tax benefit for 2017 and 2016 are negated by the full valuation allowance established as of May 31, 2016.

Employee Stock Purchase Plan

The Employee Stock Purchase Plan (the “Stock Purchase Plan”) provides a means by which employees (the “participants”) are given an opportunity to purchase the Company's common stock through payroll deductions. A total of 2,500,000 shares of common stock have been reserved for issuance under the Stock Purchase Plan. 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 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 the Company's common stock have been reserved for issuance under the Stock Purchase Plan. During the year ended May 31, 2017, an additional 500,000 shares of the Company's common stock have been reserved for issuance under the Stock Purchase Plan.

The Company uses 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 May 31, 2017, 2016 and 2015, 129,185, 137,957 and 119,001 shares, respectively, were issued at an average price of $11.00, $10.67 and $11.89, respectively, under the Stock Purchase Plan. As of May 31, 2017, 1.3 million shares remained available for future purchases under the Stock Purchase Plan.

Share Repurchases

On November 6, 2016, the Board of Directors approved the Repurchase Program under which they authorized the Company the option to repurchase up to $25.0 million of its outstanding common stock during the twenty-four month period ending November 6, 2018. During the second quarter of fiscal year 2017, the Company repurchased 500,000 shares of common stock in the open market at an aggregate cost of $7.8 million under the Repurchase Program. During the fourth quarter of fiscal year 2017, the Company repurchased 370,000 shares of common stock in the open market at an aggregate cost of $5.7 million under the Repurchase Program. As of May 31, 2017, $11.4 million remained available for repurchase under the Repurchase Program.

In February 2017, the Company retired 642,305 shares of treasury stock. These retired shares are now included in the Company’s pool of authorized but unissued shares. The retired stock had a carrying value of approximately $9.9 million and $0.01 was the par value that was deducted from common stock and the remaining $9.9 million was deducted from additional paid-in capital.

Commitments and Contingencies

12 Months Ended

May 31, 2017

Commitments and Contingencies Disclosure [Abstract]

COMMITMENTS AND CONTINGENCIES

Leases

The Company is committed under non-cancelable operating leases for facilities and equipment. During fiscal 2017, 2016 and 2015, aggregate rental costs under all operating leases were approximately $2.5 million, $2.5 million and $3.4 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, 2017, are summarized as follows (in thousands):



(in thousands)
2018	$	2,214
2019	2,066
2020	1,860
2021	1,025
2022 and thereafter	2,552
	$	9,717

Other Commitments and Contingencies

The following table summarizes the Company's other future commitments and contingencies as of May 31, 2017.



(in thousands)	Total		2018		2019		2020		2021		2022 and thereafter
Purchase obligations (1)	$	49,762	$	8,443	$	8,726	$	9,162	$	8,709	$	14,722
Royalties	44,000		2,500		3,000		3,500		3,500		31,500
Other	834		167		167		167		167		166
	$	94,596	$	11,110	$	11,893	$	12,829	$	12,376	$	46,388


(1)	The non-cancelable inventory purchase obligations are not reflected on our consolidated balance sheets under accounting principles generally accepted in the United States of America.

Legal Proceedings

The Company is involved in various legal proceedings, including commercial, intellectual property, product liability, and regulatory matters of a nature considered normal for its business. The Company accrues for amounts related to these matters if it is probable that a liability has been incurred, and an amount can be reasonably estimated. The Company discloses such matters when there is at least a reasonable possibility that a material loss may have been incurred. However, the Company cannot predict the outcome of any litigation or the potential for future litigation.

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

On January 11, 2012, C.R. Bard, Inc. (“Bard”) 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 three patents asserted by Bard in the litigation. Our petitions were granted and 40 of Bard's 41 patent claims were rejected and, following further proceedings, the Patent Office issued a Final Rejection of all 40 claims subject to reexamination. Thereafter, Bard filed appeals to the PTO Board of Appeals and Interferences for all three reexams. The parties completed briefing on the appeals and oral argument was held on June 18, 2015. The Patent Office issued decisions in the three appeals. In one (issued on March 11, 2016 for US Patent No. 7,785,302), the rejections of six of the ten claims under reexamination were affirmed, but were reversed on four of the ten claims. In the second (issued on March 24, 2016 for U.S. Patent No. 7,959,615), the rejections of eight of the ten claims under reexamination were affirmed but the rejections of the other two of the ten claims were reversed. In the third (issued on March 29 for U.S. Patent No. 7,947.022) the rejections of all twenty claims under reexamination were affirmed. Bard has since filed Requests for Rehearing in all three reexamination appeals and the Company filed Requests for Rehearing in two of the reexamination appeals (the ‘302 and ‘615 patent reexaminations). Each party has filed comments in Opposition to the other party’s Rehearing Requests,. The PTO has since issued decisions denying all Rehearing Requests - - on February 1, 2017 for the ‘302; on February 17, 2017 for the ‘022; and on February 21, 2017 for the ‘615. In the ‘302 and ‘022, the PTO modified its characterization of one prior art reference. Bard has since filed a Notice of Appeal to the Federal Circuit Court of Appeals in all three reexams and we filed Cross-Appeals in the ‘302 and the ‘615 reexams. The parties are in the process of preparing and filing the various appellate briefs, starting with Bard’s Opening Brief which is currently due on July 31, 2017 and ending with our Reply Brief which is currently due on November 6, 2017. The Utah Action has been stayed pending final resolution of the PTO process. We believe these claims are without merit and intend to defend them vigorously. We have 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. (“Bard”) filed suit in the United States District Court for the District of Delaware claiming certain of our implantable port products infringe on three U.S. patents held by Bard (the “Delaware Action). Bard is seeking unspecified damages and other relief. The patents asserted in the Delaware Action are different than those asserted in the Utah Action. On June 1, 2015, we filed two motions in response to Bard’s Complaint - one sought transfer to the District of Utah where the Utah Action is currently pending, and the other sought 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. On January 12, 2016, the court issued a decision denying both motions. We have since served an Answer and Counterclaim to which Bard has served a Reply. On March 10, 2016, the Court held a case management conference, and, on March 14, 2016, the court entered a Scheduling Order which set, inter alia, a Markman hearing for March 10, 2017, a summary judgment hearing for December 8, 2017 and trial for March 12, 2018. The parties have served various discovery requests on each other, and have been producing documents to each other; on May 27, 2016 Bard served its Infringement Contentions which identified all the port products accused of infringement; and, on June 24, 2016, we served Invalidity Contentions which detail various grounds for invalidating the three asserted patents. The parties completed briefing on the claim construction issues and the Markman hearing was held on March 10, 2017 and the Court issued its Claim Construction Order on May 19, 2017. The Court has since amended the Scheduling Order to provide for the completion of Expert Discovery on October 30, 2017; briefing on Case-Dispositive Motions between November 17, 2017 and January 24, 2018 with oral argument set for February 22, 2018 and trial to commence May 29, 2018. We believe these claims are without merit and intend to defend them vigorously. We have 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.

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

On May 30, 2017, we commenced an action in the United States District Court for the Northern District of New York entitled AngioDynamics, Inc. v. C.R. Bard, Inc. and Bard Access Systems, Inc. (“Bard”). In this action, we allege that Bard has illegally tied the sales of its tip location systems to the sales of its PICCs. We allege that this practice violates the federal antitrust laws and has had, and continues to have, an anti-competitive effect in the market for PICCs. We seek both monetary damages and injunctive relief. The Court has set an initial case management conference for August 29, 2017.

Governmental Investigations

In June 2014 we received a subpoena from the U.S. Department of Justice (the “DOJ”) requesting documents in relation to a criminal and civil 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.

In April 2015 we received a subpoena from the DOJ requesting documents in relation to a criminal and civil investigation the DOJ is conducting regarding purported promotion of certain of AngioDynamics’ VenaCure EVLT products for un-cleared indications. We are cooperating fully with this investigation.

As of May 31, 2017 the Company accrued $12.5 million for these matters and in August 2017, the Company agreed in principle with the government to resolve these matters for approximately $12.5 million.

Segments and Geographic Information

12 Months Ended

May 31, 2017

Segment Reporting [Abstract]

SEGMENTS AND GEOGRAPHIC INFORMATION

Segment information

The Company considers its 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. The Company's 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.

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



	For the year ended May 31,
(in thousands)	2017		2016		2015
Net sales by Product Category
Peripheral Vascular	$	208,602	$	205,620	$	196,890
Vascular Access	96,481		99,375		107,754
Oncology/Surgery	44,560		48,895		51,890
Total	$	349,643	$	353,890	$	356,534

Geographic information

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



	For the year ended May 31,
(in thousands)	2017		2016		2015
Net sales by Geography
United States	$	282,168	$	285,824	$	284,122
International	67,475		68,066		72,412
Total	$	349,643	$	353,890	$	356,534

For fiscal years 2017, 2016 and 2015, International sales as a percentage of total net sales were 19%, 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 net sales in any of the last three fiscal years. In addition, no one customer represents more than 10% of consolidated net sales. 99% of long-lived assets are located within the United States.

Acquisition, Restructuring and Other Items, net

12 Months Ended

May 31, 2017

Restructuring and Related Activities [Abstract]

RESTRUCTURING

RESTRUCTURING AND OTHER ITEMS, NET

For the years ended May 31, 2017, 2016 and 2015 acquisition, restructuring and other items, net consisted of:



	For the year ended May 31,
(in thousands)	2017		2016		2015
Legal	$	19,480	$	7,487	$	4,959
Intangible and other asset impairment	5,604		352		15,504
Restructuring	1,348		1,462		1,997
Other	1,078		3,290		3,797
Total	$	27,510	$	12,591	$	26,257

Of the $19.5 million in legal for fiscal year 2017, $12.5 million relates to a reserve for DOJ litigation settlement (see Note 15) and the remaining legal expenses relates to DOJ matters.

Restructuring

The Company evaluates its performance and looks for opportunities to improve the overall operations of the Company on an ongoing basis. As a result of this evaluation, certain restructuring initiatives are taken to enhance the Company’s overall operations.

Operational Consolidation

On February 1, 2017, the Company announced to employees an operational consolidation plan (the “plan”) to consolidate manufacturing facilities in Manchester, GA and Denmead, UK into the Glens Falls and Queensbury, NY facilities. This plan will streamline and optimize the manufacturing functions into one centralized location increasing the utilization of the Glens Falls and Queensbury facilities, optimizing inventory and reducing cost of goods sold through savings in overhead expenses and direct labor. The restructuring activities associated with the plan are expected to be completed in the third quarter of fiscal year 2018.

The following table provides a summary of estimated costs associated with the plan:



		Total estimated amount expected to be incurred (in millions)
Termination benefits		$1.75 to $2.25
Plant consolidation (1)		$2.25 to $2.50
Regulatory filings		$0.75 to $1.00
Contract cancellations		$0.75 to $1.00
Other		$0.75 to $1.00
		$6.25 to $7.75

(1) Equipment transfer, validation and other start-up costs to prepare the facilities for the new product lines.

The Company recorded restructuring charges related to the plan during the year ended May 31, 2017 of $1.3 million. There were no costs associated with this plan in the prior year. Termination benefits are only earned if an employee stays until their termination date; therefore, the expenses related to termination benefits are being recorded ratably over the service period.

The following table presents a rollforward of the restructuring reserve for the year ended May 31, 2017:



								Contract
	Termination		Plant			Regulatory		Cancellation		Other
	Benefits		Consolidation			Filings		Costs		Costs			Total
(in thousands)
Balance at May 31, 2016	$	—	$	—		$	—	$	—	$	—		$	—
Charges	851		494			—		—		3			1,348
Non-cash adjustments	—		(108		)	—		—		—			(108		)
Cash payments	—		(275		)	—		—		(3		)	(278		)
Balance at May 31, 2017	$	851	$	111		$	—	$	—	$	—		$	962

The Company’s restructuring liability of $1.0 million is mainly comprised of accruals for termination benefits which are expected to be paid in the next twelve months and are included in accrued expenses on the consolidated balance sheet.

Accumulated Other Comprehensive Income (Loss) (Notes)

12 Months Ended

May 31, 2017

Equity [Abstract]

Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block]

ACCUMULATED OTHER COMPREHESIVE INCOME (LOSS)

Changes in each component of accumulated other comprehensive income (loss), net of tax, are as follows for fiscal 2017 and 2016:



(in thousands)	Foreign currency translation gain (loss)			Unrealized gain (loss) on marketable securities			Unrealized gain (loss) on interest rate swap			Total
Balance at May 31, 2015	$	(648	)	$	(23	)	$	(162	)	$	(833	)
Other comprehensive income (loss) before reclassifications, net of tax	(112		)	(8		)	162			42
Amounts reclassified from accumulated other comprehensive income	—			—			—			—
Net other comprehensive income (loss)	$	(112	)	$	(8	)	$	162		$	42
Balance at May 31, 2016	$	(760	)	$	(31	)	$	—		$	(791	)
Other comprehensive income (loss) before reclassifications, net of tax	(545		)	12			—			(533		)
Amounts reclassified from accumulated other comprehensive income	—			—			—			—
Net other comprehensive income (loss)	$	(545	)	$	12		$	—		$	(533	)
Balance at May 31, 2017	$	(1,305	)	$	(19	)	$	—		$	(1,324	)

Quarterly Information (unaudited)

12 Months Ended

May 31, 2017

Quarterly Financial Information Disclosure [Abstract]

QUARTERLY INFORMATION (unaudited)

Quarterly results of operations during the fiscal years ended May 31, 2017 and 2016 are as follows:



	2017
	First quarter		Second quarter		Third quarter		Fourth quarter
(in thousands, except per share data)
Net sales	$	88,098	$	89,029	$	85,602	$	86,914
Gross profit	45,032		45,010		43,792		42,335
Net income (loss) (1)	1,300		13,734		2,887		(12,913		)
Earnings (loss) per common share
Basic	0.04		0.37		0.08		(0.35		)
Diluted	0.04		0.37		0.08		(0.35		)

(1) Included within net income (loss) during the fourth quarter of fiscal 2017 is the $12.5 million charge for a litigation reserve (Note 15) and $4.5 million impact relating to the Acculis recall (Note 10).



	2016
	First quarter			Second quarter			Third quarter		Fourth quarter
(in thousands, except per share data)
Net sales	$	83,753		$	89,284		$	87,434	$	93,419
Gross profit	43,371			45,884			43,534		41,527
Net income (loss) (1)	(775		)	(334		)	594		(43,075		)
Earnings (loss) per common share
Basic	(0.02		)	(0.01		)	0.02		(1.19		)
Diluted	(0.02		)	(0.01		)	0.02		(1.19		)

(1) Included within net income (loss) during the fourth quarter of fiscal year 2016 is the $40.4 million valuation allowance that was recorded (Note 9).

The data in the schedules above has been intentionally rounded to the nearest thousand and therefore the quarterly amounts may not sum to the full year amounts.

Valuation and Qualifying Accounts

12 Months Ended

May 31, 2017

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, 2015
Allowance for deferred tax asset	$	1,531	$	467		$	(207	)	$	1,791
Allowance for sales returns and doubtful accounts	$	1,736	$	1,846		$	(539	)	$	3,043
Year Ended May 31, 2016
Allowance for deferred tax asset	$	1,791	$	40,685		$	(267	)	$	42,209
Allowance for sales returns and doubtful accounts	$	3,043	$	3,748		$	(2,419	)	$	4,372
Year Ended May 31, 2017
Allowance for deferred tax asset	$	42,209	$	6,139		$	—		$	48,348
Allowance for sales returns and doubtful accounts	$	4,372	$	(291	)	$	(1,136	)	$	2,945

Basis of Presentation, Business Description and Summary of Significant Accounting Policies (Policies)	12 Months Ended
	May 31, 2017
Accounting Policies [Abstract]
Basis of Presentation and Description of Business	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”). The Company designs, manufactures and sells 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. The devices are generally used in minimally invasive, image-guided procedures. Most of the Company's products are intended to be used once and then discarded, or they may be temporarily implanted for short- or long-term use. Accounting Principles The consolidated financial statements and accompanying notes have been prepared in conformity with accounting principles generally accepted in the United States of America ("GAAP"). Principles of Consolidation The consolidated financial statements include the accounts of AngioDynamics and it subsidiaries (all of which are wholly owned). All intercompany balances and transactions have been eliminated. Use of Estimates 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.
Cash and Cash Equivalents	Cash and Cash Equivalents The Company considers all unrestricted highly liquid investments with an initial maturity of less than three months at the date of purchase to be cash equivalents. The Company maintains 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 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. The Company holds 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.
Fair Value Instruments	Fair Value Instruments The carrying amount of the Company's cash and cash equivalents, accounts receivable, accounts payable and long-term debt approximates fair value due to the short-term nature or market interest rates of these items. The Company bases the fair value of short-term investments on quoted market prices or other relevant information generated by market transactions involving identical or comparable assets. The Company measures and records derivative financial instruments at fair value. See Note 3 for further discussion of financial instruments that are carried at fair value on a recurring and nonrecurring basis.
Accounts Receivable	Accounts Receivable Accounts receivable, principally trade receivables, are generally due within 30 to 90 days and are stated at amounts due from customers, net of an allowance for estimated sales returns and doubtful accounts. The Company performs ongoing credit evaluations of customers and adjusts credit limits based upon payment history and the customer’s current creditworthiness, as determined by a review of their current credit information. The Company continuously monitors aging reports, collections and payments from customers, and a provision for estimated credit losses is maintained based upon historical experience and any specific customer collection issues that have been identified. While such credit losses have historically been within expectations and the provisions established, the Company cannot guarantee that the same credit loss rates will be experienced in the future. The Company writes off accounts receivable when they are determined to be uncollectible.
Inventories	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.
Goodwill and Intangible Assets	Goodwill and Intangible Assets Intangible assets other than goodwill and acquired IP R&D are amortized over their estimated useful lives, which range between two and eighteen 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. The Company periodically reviews the estimated useful lives of intangible assets and review such assets for impairment whenever events or changes in circumstances indicate that the carrying value of the asset or asset group is not recoverable. The Company determines the fair value of the reporting unit based on the market valuation approach or the income approach. If an intangible asset or asset group 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 IP R&D has an indefinite life and is not amortized until completion of the development of the project, at which time the IP R&D becomes an amortizable asset. If the related project is not completed in a timely manner or the project is terminated or abandoned, the Company may have an impairment related to the IP R&D, calculated as the excess of the asset’s carrying value over its fair value. The Company's policy defines IP R&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 IP R&D requires us to make significant estimates. The amount of the purchase price allocated to IP R&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 is the amount by which the cost of acquired net assets in a business combination exceeded the fair value of net identifiable assets on the date of purchase. 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. For goodwill, the impairment test requires a comparison of the estimated fair value of the reporting unit to which the goodwill is assigned to carrying value of the assets and liabilities of that reporting unit. The determination of reporting units also requires management judgment. The Company considers whether a reporting unit exists within a reportable segment based on the availability of discrete financial information. If carrying value of the 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. The Company utilizes either discounted cash flow models or other valuation models, such as comparative transactions and market multiples, to determine the fair value of our reporting unit. The Company makes assumptions about future cash flows, future operating plans, discount rates, comparable companies, market multiples, purchase price premiums and other factors in those models. Different assumptions and judgment determinations could yield different conclusions that would result in an impairment charge to income in the period that such change or determination was made.
Contingent Consideration	Contingent Consideration The fair value of the liability for contingent consideration recorded on the acquisition date for a business combination is based on probability weighted estimated cash flow streams, discounted back to present value using a discount rate determined in accordance with accepted valuation methods and reflective of the risk associated with the estimated cash flow streams. The liability for contingent consideration is remeasured to fair value at each reporting period with changes recorded in earnings until the contingency is resolved.
Revenue Recognition	Revenue Recognition The Company recognizes 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. The Company recognizes 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. The Company negotiates 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 the Company 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. 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 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	Income Taxes The Company calculates income tax expense for each jurisdiction in which it operates. 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. The Company periodically evaluates deferred tax assets, capital loss carryforwards and tax credit carryforwards to determine their recoverability based primarily on the Company's ability to generate future taxable income and capital gains. Where it is more-likely-than-not these will not be recovered, the Company estimates a valuation allowance and records a corresponding additional tax expense in the consolidated statement of operations. The Company recognizes and measures uncertain tax positions taken or expected to be taken in a tax return utilizing a two-step approach. The Company first determines if the weight of available evidence indicates that it is more likely than not that the tax position will be sustained on audit, including resolution of any related appeals or litigation processes. The second step is that the Company measures the tax benefit as the largest amount that is more likely than not to be realized upon ultimate settlement. The Company recognizes interest and penalties related to uncertain tax positions in the provision for income taxes on the consolidated statements of operations.
Warranty Costs	Warranty Costs The Company makes periodic provisions for expected warranty costs. Historically, warranty costs have been insignificant.
Share-based Compensation, Option and Incentive Plans Policy [Policy Text Block]	Stock Based Compensation Stock-based compensation expense reflects the fair value of stock-based awards measured at the grant date and recognized over the relevant service period. The Company estimates the fair value of each stock-based award on the measurement date using either the current market price of the stock, the Black-Scholes option valuation model, or the Monte Carlo Simulation valuation model. The Black-Scholes and Monte Carlo Simulation valuation models incorporate assumptions as to stock price volatility, the expected life of options or restricted stock units, a risk-free interest rate and dividend yield. The Company recognizes stock-based compensation expense related to options, restricted stock units and market based performance stock units on a straight-line basis over the service period of the award, which is generally 4 years for options and restricted stock units and 3 years for market based performance stock units.
Foreign Currency Translation	Foreign Currency Translation The functional currency of most of the Company's foreign subsidiaries is the local currency in which the subsidiary operates. For foreign operations where the local currency is considered to be the functional currency, the Company translates assets and liabilities into U.S. dollars at the exchange rate on the balance sheet date. The Company translates income and expense items at average rates of exchange prevailing during each period. The Company accumulates translation adjustments in accumulated other comprehensive loss, a component of stockholders’ equity. For foreign operations where the U.S. dollar is considered to be the functional currency, the Company remeasures monetary assets and liabilities into U.S. dollars at the exchange rate on the balance sheet date and non-monetary assets and liabilities are remeasured into U.S. dollars at historical exchange rates. The Company translates income and expense items at average rates of exchange prevailing during each period. The Company recognizes remeasurement adjustments as a component of other expense in the consolidated statements of operations. Transaction gains or losses that arise from exchange rate fluctuations on transactions denominated in a currency other than the functional currency are included in other expense in the statements of operations as incurred.
Derivative Financial Instruments	Derivative Financial Instruments The Company is exposed to market risks, including changes in foreign currency and interest rates. The Company periodically enters into certain derivative financial instruments to hedge the underlying economic exposure. 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).
Contingencies	Contingencies The Company is subject to various legal proceedings that arise in the ordinary course of business, including patent infringement and product liability matters. The Company records accruals for contingencies when it is probable the liability has been incurred and the amount can be reasonably estimated. Legal fees are expensed as incurred. Insurance recoveries related to potential claims are recognized up to the amount of the recorded liability when coverage is confirmed and the estimated recoveries are probable of payment. These recoveries are not netted against the related liabilities for financial statement presentation.
Recently Issued Accounting Pronouncements	Recently Issued Accounting Pronouncements - Adopted In April 2015, the Financial Accounting Standards Board ("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. This was adopted in the first quarter of fiscal 2017 and the Company reclassified $0.9 million from other assets to long-term debt, net in the balance sheet as of May 31, 2016. Recently Issued Accounting Pronouncements - Not Yet Applicable or Adopted In May 2014, the 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 2019, 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 evaluating the impact of ASU 2014-09 on its consolidated financial statements. In July 2015, the FASB issued ASC Update No. 2015-11, Inventory (Topic 330): Simplifying the Measurement of Inventory. Update No. 2015-11 more closely aligns the measurement of inventory in U.S. GAAP with the measurement of inventory in International Financial Reporting Standards by requiring companies using the first-in, first-out and average costs methods to measure inventory using the lower of cost and net realizable value, where net realizable value is the estimated selling prices in the ordinary course of business, less reasonably predictable costs of completion, disposal, and transportation. Update No. 2015-11 is effective for annual reporting periods beginning after December 15, 2016 and interim periods within those fiscal years. Update No. 2015-11 should be applied prospectively with earlier application permitted as of the beginning of an interim or annual reporting period. The adoption of Update No. 2015-11 is not expected to have a material impact on the Company's financial position or results of operations. In February 2016, the FASB issued ASU 2016-02, Leases (Topic 842). ASU 2016-02 increases transparency and comparability among organizations by recognizing lease assets and liabilities on the balance sheet and disclosing key information about leasing arrangements. For leases with a term or twelve months or less, a lessee is permitted to make an accounting policy election by class of underlying asset not to recognize lease assets and liabilities. ASU 2016-02 is effective for fiscal years beginning after December 15, 2018 and early application is permitted. The Company is currently in the process of evaluating the impact of ASU 2016-02 on its consolidated financial statements. In March 2016, the FASB issued ASU 2016-09, Compensation - Stock Based Compensation (Topic 718: Improvements to Employee Share-Based Payment Accounting). ASU 2016-09 simplifies and improves various aspects of ASC 718 for share-based payments, including income tax items and the classification of these items on the statement of cash flows. ASU 2016-09 is effective for annual periods beginning after December 31, 2016 and early application is permitted. The Company is currently in the process of evaluating the impact of ASU 2016-09 on its consolidated financial statements. In August 2016, the FASB issued ASU No. 2016-15, Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments (ASU 2016-15). ASU 2016-15 identifies how certain cash receipts and cash payments are presented and classified in the Statement of Cash Flows under Topic 230. ASU 2016-15 is effective for the Company for fiscal years beginning after December 15, 2017, and interim periods within those fiscal years. ASU 2016-15 should be applied retrospectively and early adoption is permitted, including adoption in an interim period. The Company is currently in the process of evaluating the impact of ASU 2016-15 on its consolidated financial statements. In January 2017, the FASB issued ASU 2017-04, Intangibles - Goodwill and Other (Topic 350), which simplifies the subsequent measurement of goodwill by eliminating steps from the goodwill impairment test. ASU 2017-04 should be adopted for annual or interim goodwill impairment tests in fiscal years beginning after December 15, 2019. ASU 2017-04 should be applied prospectively and early adoptions is permitted, including adoption in an interim period. The Company is currently evaluating the impact of ASU 2017-04 on its consolidated financial statements.

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

12 Months Ended

May 31, 2017

Accounting Policies [Abstract]

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

roperty, plant and equipment are summarized as follows:



	May 31, 2017			May 31, 2016
(in thousands)
Building and building improvements	$	40,597		$	39,585
Machinery and equipment	25,434			24,078
Computer software and equipment	25,668			24,691
Construction in progress	1,464			1,743
	93,163			90,097
Less accumulated depreciation and amortization	(49,652		)	(43,536		)
	43,511			46,561
Land and land improvements	1,723			1,723
	$	45,234		$	48,284

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

12 Months Ended

May 31, 2017

Fair Value Disclosures [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 on a recurring basis:



	Fair Value Measurements using inputs considered as:
(in thousands)	Level 1		Level 2		Level 3		Fair Value at May 31, 2017
Financial Assets
Marketable securities	$	—	$	—	$	1,215	$	1,215
Total Financial Assets	$	—	$	—	$	1,215	$	1,215
Financial Liabilities
Contingent liability for acquisition earn outs	$	—	$	—	$	12,761	$	12,761
Total Financial Liabilities	$	—	$	—	$	12,761	$	12,761



	Fair Value Measurements using inputs considered as:
(in thousands)	Level 1		Level 2		Level 3		Fair Value at May 31, 2016
Financial Assets
Marketable securities	$	—	$	—	$	1,653	$	1,653
Total Financial Assets	$	—	$	—	$	1,653	$	1,653
Financial Liabilities
Contingent liability for acquisition earn outs	$	—	$	—	$	38,275	$	38,275
Total Financial Liabilities	$	—	$	—	$	38,275	$	38,275

Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation

The table below presents the changes in fair value components of Level 3 instruments in the year ended May 31, 2017 (in thousands of dollars):



	Financial Assets			Financial Liabilities
(in thousands)	Fair Value Measurements Using Significant Unobservable Inputs (Level 3)			Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
Balance at May 31, 2016	$	1,653		$	38,275
Change in fair value of contingent consideration, net (1)	—			(15,261		)
Currency (gain) loss from remeasurement	—			(153		)
Fair market value adjustments	12			—
Sale of securities	(450		)	—
Contingent consideration payments	—			(10,100		)
Balance at May 31, 2017	$	1,215		$	12,761

The Company decided to terminate its agreement with EmboMedics which resulted in a $2.0 million write-off of our investment in EmboMedics (Note 2).

The table below presents the changes in fair value components of Level 3 instruments in the year ended May 31, 2016 (in thousands of dollars):



	Financial Assets			Financial Liabilities
(in thousands)	Fair Value Measurements Using Significant Unobservable Inputs (Level 3)			Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
Balance at May 31, 2015	$	1,689		$	47,384
Change in fair value of contingent consideration (1)	—			948
Currency (gain) loss from remeasurement	—			43
Fair market value adjustments	(36		)	—
Contingent consideration payments	—			(10,100		)
Balance at May 31, 2016	$	1,653		$	38,275

Fair Value, Liabilities Measured on Recurring Basis

The recurring Level 3 fair value measurements of the contingent consideration liabilities include the following significant unobservable inputs as of May 31, 2017:



(in thousands)	Fair value at May 31, 2017		Valuation Technique	Unobservable Input	Range
Revenue based payments	$	12,761	Discounted cash flow	Discount rate Probability of payment Projected fiscal year of payment	4% 100% 2018 - 2022

Marketable Securities (Tables)

12 Months Ended

May 31, 2017

Investments, Debt and Equity Securities [Abstract]

Marketable securities

As of May 31, 2017, 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	$	1,350	$	—	$	(135	)	$	1,215
	$	1,350	$	—	$	(135	)	$	1,215

As of May 31, 2016, 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	$	1,800	$	—	$	(147	)	$	1,653
	$	1,800	$	—	$	(147	)	$	1,653

Amortized cost and fair value of marketable securities by contractual maturity



	Amortized cost		Fair Value
(in thousands)
As of May 31, 2017:
Due in one year or less	$	—	$	—
Due after one through five years	—		—
Due after five through twenty years (1)	1,350		1,215
	$	1,350	$	1,215

(1) This auction rate security represents investments available for current operations and are classified as current in the consolidated balance sheets.

Inventories (Tables)

12 Months Ended

May 31, 2017

Inventory Disclosure [Abstract]

Inventories

As of May 31, 2017 and 2016, inventories consisted of the following:



	May 31, 2017		May 31, 2016
(in thousands)
Raw materials	$	17,563	$	21,669
Work in process	12,602		10,700
Finished goods	24,341		23,001
Total	$	54,506	$	55,370

Property, Plant and Equipment, Net (Tables)

12 Months Ended

May 31, 2017

Property, Plant and Equipment [Abstract]

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

roperty, plant and equipment are summarized as follows:



	May 31, 2017			May 31, 2016
(in thousands)
Building and building improvements	$	40,597		$	39,585
Machinery and equipment	25,434			24,078
Computer software and equipment	25,668			24,691
Construction in progress	1,464			1,743
	93,163			90,097
Less accumulated depreciation and amortization	(49,652		)	(43,536		)
	43,511			46,561
Land and land improvements	1,723			1,723
	$	45,234		$	48,284

Goodwill and Intangible Assets (Tables)

12 Months Ended

May 31, 2017

Goodwill and Intangible Assets Disclosure [Abstract]

Intangible assets

As of May 31, 2017 and 2016, intangible assets consisted of the following:



	May 31, 2017
	Gross carrying value		Accumulated amortization			Net carrying value
(in thousands)
Product technologies	$	147,172	$	(59,696	)	$	87,476
Customer relationships	56,375		(19,194		)	37,181
Trademarks	28,400		(9,069		)	19,331
Licenses	4,487		(3,821		)	666
Distributor relationships	1,250		(229		)	1,021
	$	237,684	$	(92,009	)	$	145,675



	May 31, 2016
	Gross carrying value		Accumulated amortization			Net carrying value
(in thousands)
Product technologies	$	148,387	$	(51,313	)	$	97,074
Customer relationships	88,389		(47,133		)	41,256
Trademarks	28,470		(6,242		)	22,228
Licenses	7,931		(6,716		)	1,215
Distributor relationships	2,150		(946		)	1,204
In process R&D	3,600		—			3,600
	$	278,927	$	(112,350	)	$	166,577

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)
2018	$	16,500
2019	16,132
2020	14,578
2021	13,627
2022	12,952
2023 and thereafter	71,886
	$	145,675

Income Taxes (Tables)

12 Months Ended

May 31, 2017

Income Tax Disclosure [Abstract]

Components of income (loss) before income tax provision

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



	2017		2016			2015
(in thousands)
Income (loss) before tax expense:
US	$	8,825	$	(4,444	)	$	(8,965	)
Non-US	1,022		1,191			834
	$	9,847	$	(3,253	)	$	(8,131	)

Summary of Income tax (benefit) provision analyzed by category

Income tax expense (benefit) is comprised of the following:



	2017		2016		2015
(in thousands)
Current
Federal	$	—	$	34	$	(242	)
State and local	141		103		205
Non U.S.	270		217		417
	411		354		380
Deferred	4,428		39,983		(5,123		)
Income tax expense (benefit)	$	4,839	$	40,337	$	(4,743	)

Summary of deferred tax asset and liabilities

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



	May 31, 2017			May 31, 2016
(in thousands)
Deferred tax assets
Net operating loss carryforward	$	55,975		$	52,593
Stock-based compensation	2,653			4,135
Federal and state R&D tax credit carryforward	2,548			2,145
Inventories	2,407			4,535
Expenses incurred not currently deductible	6,522			3,018
Accrued liabilities	1,289			339
Gross deferred tax asset	71,394			66,765
Deferred tax liabilities
Excess tax over book depreciation and amortization	49,158			46,240
	49,158			46,240
Valuation Allowance	(48,348		)	(42,209		)
Net deferred tax liability	$	(26,112	)	$	(21,684	)

Summary of Income tax rate reconciliation



	For the year ended May 31,
	2017			2016			2015
(in thousands)
Income tax expense (benefit) at statutory tax rate of 35%	$	3,447		$	(1,139	)	$	(2,845	)
Effect of graduated tax rates	(98		)	33			81
State income taxes, net of Federal tax benefit	(22		)	(215		)	(21		)
Impact of Non-US operations	403			(162		)	133
Research and development tax credit	(403		)	(499		)	(604		)
Meals and entertainment	266			329			—
Non-deductible interest on contingent payments	174			262			265
Non-taxable gain on revaluation of contingent consideration liability	(5,576		)	(170		)	(3,102		)
Tax law changes	—			—			(454		)
Change in valuation allowance	6,139			40,685			—
Effect of elimination of stock compensation APIC pool	1,380			739			1,253
IPR&D intangible write-off	(1,224		)	—			—
Other nondeductible expenses	219			207			498
Over (under) accrual of prior year Federal and State taxes	(3		)	356			38
Other	137			(89		)	15
Income tax expense (benefit)	$	4,839		$	40,337		$	(4,743	)

Stockholders' Equity (Tables)

12 Months Ended

May 31, 2017

Equity [Abstract]

Schedule summarizes stock option activity

The following table summarizes information about stock option activity for the fiscal year ended May 31, 2017.



	2017
	Shares		Weighted- average exercise price		Weighted average remaining contractual life	Aggregate intrinsic value (in thousands)
Outstanding at beginning of year	2,281,618		$	14.45
Granted	667,691		$	16.83
Exercised	(826,286	)	$	13.45
Forfeited	(342,924	)	$	16.03
Expired	(112,656	)	$	19.08
Outstanding at end of year	1,667,443		$	15.01	4.66	$	1,513
Options exercisable at year-end	659,463		$	14.26	2.88	$	913
Options expected to vest in future periods	884,906		$	15.50	5.83	$	527

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

The following table summarizes information about performance unit award activity for the year ended May 31, 2017.



	Performance Unit Awards		Weighted Average Grant-Date Fair Value
Non-vested at beginning of year	435,892		$	19.16
Granted	93,400		$	22.61
Vested	(37,184	)	$	14.48
Canceled	(130,944	)	$	21.54
Non-vested at end of year	361,164		$	18.54

The following table summarizes information about restricted stock unit activity for the year ended May 31, 2017.



			Weighted Average Grant-Date Fair Value
Non-vested at beginning of year	549,777		$	14.62
Granted	255,032		$	16.54
Vested	(182,320	)	$	16.10
Canceled	(183,192	)	$	15.95
Non-vested at end of year	439,297		$	15.55

Schedule of Employee Service Share-based Compensation, Allocation of Recognized Period Costs

The following tables represents the break out of share-based compensation included in the Company's consolidated statement of operations.



	For the year ended May 31,
(in thousands)	2017			2016			2015
Cost of sales	$	299		$	172		$	143
Research and development	314			349			229
Sales and marketing	1,762			1,489			1,685
General and administrative	4,026			2,291			3,941
Acquisition, restructuring and other items, net	(218		)	(1,061		)	—
	$	6,183		$	3,240		$	5,998

Commitments And Contingencies (Tables)

12 Months Ended

May 31, 2017

Commitments and Contingencies Disclosure [Abstract]

Aggregate of future annual payments under non cancelable operating leases for facilities and equipment

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, 2017, are summarized as follows (in thousands):



(in thousands)
2018	$	2,214
2019	2,066
2020	1,860
2021	1,025
2022 and thereafter	2,552
	$	9,717

Other commitments and contingencies

The following table summarizes the Company's other future commitments and contingencies as of May 31, 2017.



(in thousands)	Total		2018		2019		2020		2021		2022 and thereafter
Purchase obligations (1)	$	49,762	$	8,443	$	8,726	$	9,162	$	8,709	$	14,722
Royalties	44,000		2,500		3,000		3,500		3,500		31,500
Other	834		167		167		167		167		166
	$	94,596	$	11,110	$	11,893	$	12,829	$	12,376	$	46,388


(1)	The non-cancelable inventory purchase obligations are not reflected on our consolidated balance sheets under accounting principles generally accepted in the United States of America.

Segments and Geographic Information (Tables)

12 Months Ended

May 31, 2017

Segment Reporting [Abstract]

Summary of total net sales by product category

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



	For the year ended May 31,
(in thousands)	2017		2016		2015
Net sales by Product Category
Peripheral Vascular	$	208,602	$	205,620	$	196,890
Vascular Access	96,481		99,375		107,754
Oncology/Surgery	44,560		48,895		51,890
Total	$	349,643	$	353,890	$	356,534

Summary of net sales for geographic areas

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



	For the year ended May 31,
(in thousands)	2017		2016		2015
Net sales by Geography
United States	$	282,168	$	285,824	$	284,122
International	67,475		68,066		72,412
Total	$	349,643	$	353,890	$	356,534

Acquisition, Restructuring and Other Items, net (Tables)

12 Months Ended

May 31, 2017

Restructuring and Related Activities [Abstract]

Restructuring and Related Costs [Table Text Block]

The following table presents a rollforward of the restructuring reserve for the year ended May 31, 2017:



								Contract
	Termination		Plant			Regulatory		Cancellation		Other
	Benefits		Consolidation			Filings		Costs		Costs			Total
(in thousands)
Balance at May 31, 2016	$	—	$	—		$	—	$	—	$	—		$	—
Charges	851		494			—		—		3			1,348
Non-cash adjustments	—		(108		)	—		—		—			(108		)
Cash payments	—		(275		)	—		—		(3		)	(278		)
Balance at May 31, 2017	$	851	$	111		$	—	$	—	$	—		$	962

The following table provides a summary of estimated costs associated with the plan:



		Total estimated amount expected to be incurred (in millions)
Termination benefits		$1.75 to $2.25
Plant consolidation (1)		$2.25 to $2.50
Regulatory filings		$0.75 to $1.00
Contract cancellations		$0.75 to $1.00
Other		$0.75 to $1.00
		$6.25 to $7.75

For the years ended May 31, 2017, 2016 and 2015 acquisition, restructuring and other items, net consisted of:



	For the year ended May 31,
(in thousands)	2017		2016		2015
Legal	$	19,480	$	7,487	$	4,959
Intangible and other asset impairment	5,604		352		15,504
Restructuring	1,348		1,462		1,997
Other	1,078		3,290		3,797
Total	$	27,510	$	12,591	$	26,257

Quarterly Information (unaudited) (Tables)

12 Months Ended

May 31, 2017

Quarterly Financial Information Disclosure [Abstract]

Summary of Quarterly Financial Information

Quarterly results of operations during the fiscal years ended May 31, 2017 and 2016 are as follows:



	2017
	First quarter		Second quarter		Third quarter		Fourth quarter
(in thousands, except per share data)
Net sales	$	88,098	$	89,029	$	85,602	$	86,914
Gross profit	45,032		45,010		43,792		42,335
Net income (loss) (1)	1,300		13,734		2,887		(12,913		)
Earnings (loss) per common share
Basic	0.04		0.37		0.08		(0.35		)
Diluted	0.04		0.37		0.08		(0.35		)



	2016
	First quarter			Second quarter			Third quarter		Fourth quarter
(in thousands, except per share data)
Net sales	$	83,753		$	89,284		$	87,434	$	93,419
Gross profit	43,371			45,884			43,534		41,527
Net income (loss) (1)	(775		)	(334		)	594		(43,075		)
Earnings (loss) per common share
Basic	(0.02		)	(0.01		)	0.02		(1.19		)
Diluted	(0.02		)	(0.01		)	0.02		(1.19		)

Basis of Presentation, Business Description and Summary of Significant Accounting Policies (Details Textual) $ in Thousands	12 Months Ended
	May 31, 2017 USD ($) Investment	May 31, 2016 USD ($)	May 31, 2015 USD ($)
Business Acquisition [Line Items]
Short Term Investments Maturity Period	less than three months
Investments in auction rate securities that failed auctions	$ 1,200
Number of investments \| Investment	2
Restocking charge percentage	20.00%
Prior period reclassification adjustment		$ 1,000	$ 900
Long-term debt	$ 96,320
Maximum
Business Acquisition [Line Items]
Accounts receivables period due	90 days
Weighted average useful life	18 years
Minimum
Business Acquisition [Line Items]
Accounts receivables period due	30 days
Weighted average useful life	2 years
Undamaged product expiration date	12 months
Machinery and equipment \| Maximum
Business Acquisition [Line Items]
Useful life	8 years
Machinery and equipment \| Minimum
Business Acquisition [Line Items]
Useful life	3 years
Building and building improvements
Business Acquisition [Line Items]
Useful life	39 years
Computer software and equipment \| Maximum
Business Acquisition [Line Items]
Useful life	10 years
Computer software and equipment \| Minimum
Business Acquisition [Line Items]
Useful life	3 years
ASC Update No. 2015-03
Business Acquisition [Line Items]
Other assets	$ 900
Long-term debt	$ 900
New Accounting Pronouncement, Early Adoption, Effect [Member] \| Long-term Debt [Member]
Business Acquisition [Line Items]
Debt Issuance Costs, Net		900
New Accounting Pronouncement, Early Adoption, Effect [Member] \| Other Assets [Member]
Business Acquisition [Line Items]
Debt Issuance Costs, Net		$ 900

Other Assets (Details) - USD ($) $ in Millions		3 Months Ended
Other Assets (Details) - USD ($) $ in Millions	Dec. 07, 2015	Feb. 28, 2017
Investments in and Advances to Affiliates [Line Items]
Purchase of non-transferable warrants	$ 2.0
Affiliated Entity
Investments in and Advances to Affiliates [Line Items]
Asset Impairment Charges		$ 2.0

Fair Value of Financial Instruments Fair Value of Financial Instruments (Details) - Recurring - USD ($) $ in Thousands	May 31, 2017	May 31, 2016
Financial Assets
Total Financial Assets	$ 1,215	$ 1,653
Financial Liabilities
Total Financial Liabilities	12,761	38,275
Contingent liability for acquisition earn outs
Financial Liabilities
Total Financial Liabilities	12,761	38,275
Marketable securities
Financial Assets
Marketable securities	1,215	1,653
Level 1
Financial Assets
Total Financial Assets	0	0
Financial Liabilities
Total Financial Liabilities	0	0
Level 1 \| Contingent liability for acquisition earn outs
Financial Liabilities
Total Financial Liabilities	0	0
Level 1 \| Marketable securities
Financial Assets
Marketable securities	0	0
Level 2
Financial Assets
Total Financial Assets	0	0
Financial Liabilities
Total Financial Liabilities	0	0
Level 2 \| Contingent liability for acquisition earn outs
Financial Liabilities
Total Financial Liabilities	0	0
Level 2 \| Marketable securities
Financial Assets
Marketable securities	0	0
Level 3
Financial Assets
Total Financial Assets	1,215	1,653
Financial Liabilities
Total Financial Liabilities	12,761	38,275
Level 3 \| Contingent liability for acquisition earn outs
Financial Liabilities
Total Financial Liabilities	12,761	38,275
Level 3 \| Marketable securities
Financial Assets
Marketable securities	$ 1,215	$ 1,653

Fair Value of Financial Instruments Fair Value of Financial Instruments (Details 2) - USD ($) $ in Thousands	12 Months Ended
	May 31, 2017	May 31, 2016
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	$ 1,653	$ 1,689
Change in fair value of contingent consideration and currency (gain) loss from remeasurement	0	0
Fair market value adjustments	12	(36)
Sale of securities	(450)
Contingent consideration payments	0	0
Ending balance	1,215	1,653
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	38,275	47,384
Change in fair value of contingent consideration	(15,261)	948
Currency (gain) loss from remeasurement	(153)	43
Fair market value adjustments	0	0
Sale of securities	0
Contingent consideration payments	(10,100)	(10,100)
Ending balance	$ 12,761	$ 38,275

Fair Value of Financial Instruments Fair Value of Financial Instruments (Details 3) - USD ($) $ in Thousands		12 Months Ended
	Dec. 07, 2015	May 31, 2017	May 31, 2016	May 31, 2015
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Contingent consideration liability at fair value		$ 12,761	$ 38,275	$ 47,384
Potential amount of undiscounted future contingent consideration		13,100
Purchase of non-transferable warrants	$ 2,000
Revenue based payments \| Level 3 \| Contingent liability for acquisition earn outs \| Recurring
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Contingent consideration liability at fair value		$ 12,761
Summary showing the recurring fair value measurements of the contingent consideration liability
Discount rate used in fair value calculation		4.00%
Revenue based payments \| Level 3 \| Maximum \| Contingent liability for acquisition earn outs \| Recurring
Summary showing the recurring fair value measurements of the contingent consideration liability
Probability of payment		100.00%
Discontinued Investment in TiLo Product [Member] \| Disposal Group, Disposed of by Means Other than Sale, Not Discontinued Operations, Abandonment [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair Value, Liabilities Measured on Recurring Basis, Change in Unrealized Gain (Loss)		$ 3,100
Discontinued Investment in TiLo Product [Member] \| Disposal Group, Disposed of by Means Other than Sale, Not Discontinued Operations, Abandonment [Member] \| In Process Research and Development [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Disposal Group, Not Discontinued Operation, Loss (Gain) on Write-down		3,600
AngioVac Product [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair Value, Liabilities Measured on Recurring Basis, Change in Unrealized Gain (Loss)		$ 13,400

Marketable Securities (Details) - USD ($) $ in Thousands	May 31, 2017	May 31, 2016
Marketable securities
Amortized cost	$ 1,350	$ 1,800
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(135)	(147)
Fair Value	1,215	1,653
Marketable securities
Marketable securities
Amortized cost	1,350	1,800
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(135)	(147)
Fair Value	$ 1,215	$ 1,653

Marketable Securities (Details 1) - USD ($) $ in Thousands	May 31, 2017	May 31, 2016
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	1,350
Amortized cost	1,350	$ 1,800
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	1,215
Fair Value, Total	$ 1,215

Inventories (Details) - USD ($) $ in Thousands	12 Months Ended
Inventories (Details) - USD ($) $ in Thousands	May 31, 2017	May 31, 2016
Inventories
Raw materials	$ 17,563	$ 21,669
Work in process	12,602	10,700
Finished goods	24,341	23,001
Total	54,506	55,370
Inventory valuation reserve	7,300	12,600
Inventory write-off	$ 2,400	$ 5,800

Prepaid Expenses and Other (Details) - USD ($) $ in Thousands	May 31, 2017	May 31, 2016
Prepaid expenses and other
Software licenses	$ 582	$ 282
License fees	118	108
Trade shows	162	278
Rent	121	127
Other prepaid taxes	208	160
Medical device excise tax receivable	1,837	0
Other	2,762	2,288
Total	$ 5,790	$ 3,243

Property, Plant, and Equipment, Net (Details) - USD ($) $ in Thousands	12 Months Ended
	May 31, 2017	May 31, 2016	May 31, 2015
Property, plant and equipment
Property, plant and equipment	$ 93,163	$ 90,097
Less accumulated depreciation and amortization	(49,652)	(43,536)
Property, plant and equipment excluding land and land improvements	43,511	46,561
Land and land improvements	1,723	1,723
Property, plant and equipment, Net	45,234	48,284
Depreciation expense	6,000	8,200	$ 9,800
Building and building improvements
Property, plant and equipment
Property, plant and equipment	40,597	39,585
Machinery and equipment
Property, plant and equipment
Property, plant and equipment	25,434	24,078
Computer software and equipment
Property, plant and equipment
Property, plant and equipment	25,668	24,691
Construction in progress
Property, plant and equipment
Property, plant and equipment	$ 1,464	$ 1,743

Goodwill and Intangible Assets (Details Textual)		12 Months Ended
Goodwill and Intangible Assets (Details Textual)	Dec. 31, 2016 USD ($)	May 31, 2017 USD ($) Segment	May 31, 2016 USD ($)	May 31, 2015 USD ($)
Goodwill and Intangible Assets (Textual) [Abstract]
Number of Reportable Segments \| Segment		1
Goodwill, Impairment Loss	$ 0
Goodwill, period increase (decrease)		$ 0	$ 0
Amortization expense		$ 17,296,000	$ 17,964,000	$ 17,966,000
Minimum
Goodwill and Intangible Assets (Textual) [Abstract]
Estimates useful life of intangible assets other than goodwill		2 years
Maximum
Goodwill and Intangible Assets (Textual) [Abstract]
Estimates useful life of intangible assets other than goodwill		18 years

Goodwill and Intangible Assets (Details 1) - USD ($) $ in Thousands	May 31, 2017	May 31, 2016
Indefinite-lived Intangible Assets [Line Items]
Intangible Assets, Gross (Excluding Goodwill)	$ 237,684	$ 278,927
Accumulated amortization	(92,009)	(112,350)
Net carrying value, finite-lived intangible assets	145,675
Intangible Assets, Net (Excluding Goodwill)	145,675	166,577
Product technologies
Indefinite-lived Intangible Assets [Line Items]
Gross carrying value, finite-lived intangible assets	147,172	148,387
Accumulated amortization	(59,696)	(51,313)
Net carrying value, finite-lived intangible assets	87,476	97,074
Customer relationships
Indefinite-lived Intangible Assets [Line Items]
Gross carrying value, finite-lived intangible assets	56,375	88,389
Accumulated amortization	(19,194)	(47,133)
Net carrying value, finite-lived intangible assets	37,181	41,256
Trademarks
Indefinite-lived Intangible Assets [Line Items]
Gross carrying value, finite-lived intangible assets	28,400	28,470
Accumulated amortization	(9,069)	(6,242)
Net carrying value, finite-lived intangible assets	19,331	22,228
Licenses
Indefinite-lived Intangible Assets [Line Items]
Gross carrying value, finite-lived intangible assets	4,487	7,931
Accumulated amortization	(3,821)	(6,716)
Net carrying value, finite-lived intangible assets	666	1,215
Distributor relationships
Indefinite-lived Intangible Assets [Line Items]
Gross carrying value, finite-lived intangible assets	1,250	2,150
Accumulated amortization	(229)	(946)
Net carrying value, finite-lived intangible assets	$ 1,021	1,204
In process R&D
Indefinite-lived Intangible Assets [Line Items]
Indefinite-Lived Intangible Assets (Excluding Goodwill)		3,600
Indefinite Lived Intangible Assets Excluding Goodwill Net		$ 3,600

Goodwill and Intangible Assets (Details 2) $ in Thousands	May 31, 2017 USD ($)
Expected amortization expense
2018	$ 16,500
2019	16,132
2020	14,578
2021	13,627
2022	12,952
2023 and thereafter	71,886
Net carrying value, finite-lived intangible assets	$ 145,675

Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
Income Taxes (Details) - USD ($) $ in Thousands	May 31, 2017	May 31, 2016	May 31, 2015
Components of income (loss) before income tax provision
US	$ 8,825	$ (4,444)	$ (8,965)
Non-US	1,022	1,191	834
Total other (expenses) income, net	$ 9,847	$ (3,253)	$ (8,131)

Income Taxes (Details 1) - USD ($) $ in Thousands	12 Months Ended
Income Taxes (Details 1) - USD ($) $ in Thousands	May 31, 2017	May 31, 2016	May 31, 2015	May 31, 2014
Current
Federal	$ 0	$ 34	$ (242)
State and local	141	103	205
Non U.S.	270	217	417
Current, Total	411	354	380
Deferred	4,428	39,983	(5,123)
Income tax expense/(benefit), Total	$ 4,839	$ 40,337	$ (4,743)	$ (9,200)

Income Taxes (Details 3) - USD ($) $ in Thousands	May 31, 2017	May 31, 2016
Deferred tax assets
Net operating loss carryforward	$ 55,975	$ 52,593
Stock-based compensation	2,653	4,135
Federal and state R&D tax credit carryforward	2,548	2,145
Inventories	2,407	4,535
Expenses incurred not currently deductible	6,522	3,018
Deferred revenue	1,289	339
Gross deferred tax asset	71,394	66,765
Deferred tax liabilities
Excess tax over book depreciation and amortization	49,158	46,240
Gross deferred Liability	49,158	46,240
Valuation Allowance	(48,348)	(42,209)
Net deferred tax liability	$ (26,112)	$ (21,684)

Income Taxes (Details 4) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
Income Taxes (Details 4) - USD ($) $ in Thousands	Aug. 31, 2015	Aug. 31, 2014	May 31, 2017	May 31, 2016	May 31, 2015	May 31, 2014
Reasons for consolidated income tax provision
Effective income tax rate	35.00%	35.00%	35.00%
Income tax (benefit) provision at statutory tax rate of 35%			$ 3,447	$ (1,139)	$ (2,845)
Effect of Graduated tax rates			(98)	33	81
State income taxes, net of Federal tax benefit			(22)	(215)	(21)
Impact of Non US operations			403	(162)	133
Research and development tax credit			(403)	(499)	(604)
Meals and entertainment			266	329	0
Nondeductible interest on contingent payments			174	262	265
Nontaxable gain on revaluation of contingent consideration liability			(5,576)	(170)	(3,102)
Tax law change			0	0	(454)
Change in valuation allowance			6,139	40,685	0
Effect of elimination of ASC 718 APIC pool			1,380	739	1,253
Nondeductible stock-based compensation			(1,224)	0	0
Other nondeductible expenses			219	207	498
Overaccrual (underaccrual) of prior year Federal and state taxes			(3)	356	38
Other			137	(89)	15
Income tax expense/(benefit), Total			$ 4,839	$ 40,337	$ (4,743)	$ (9,200)

Income Taxes Income Taxes (Details 5) - USD ($) $ in Thousands	12 Months Ended
	May 31, 2017	May 31, 2016	May 31, 2015
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Unrecognized tax benefits, beginning balance	$ 899	$ 0	$ 0
Increase in gross amounts of tax positions related to prior years	0	899	0
Unrecognized tax benefits, ending balance	$ 899	$ 899	$ 0

Income Taxes (Details Textual) - USD ($)	12 Months Ended
Income Taxes (Details Textual) - USD ($)	May 31, 2017	May 31, 2016	May 31, 2015	May 31, 2014
Income Taxes (Textual) [Abstract]
Income tax expense (benefit)	$ 4,839,000	$ 40,337,000	$ (4,743,000)	$ (9,200,000)
Valuation allowance		(40,400,000)
Potential increase in equity if excess tax benefits are realized	600,000
Accrued interest and penalties	0	$ 0		$ 0
Unrecognized tax benefits	100,000
Additional unrecognized tax benefit	800,000
Foreign subsidiary undistributed earnings	5,300,000
Federal
Income Taxes (Textual) [Abstract]
Net operating loss carryforwards after considering limitations of use	161,600,000
Tax Year 2017 To 2016 \| Federal
Income Taxes (Textual) [Abstract]
Federal and State net operating loss carryforwards	29,800,000
Tax Year 2027 To 2033 \| Federal
Income Taxes (Textual) [Abstract]
Net operating loss carryforwards after considering limitations of use	131,800,000
Tax Year 2015 To 2033 \| State
Income Taxes (Textual) [Abstract]
Federal and State net operating loss carryforwards	$ 32,700,000

Accrued Liabilities (Details) - USD ($) $ in Thousands	May 31, 2017	May 31, 2016
Accrued liabilities
Payroll and related expenses	$ 11,383	$ 9,414
Royalties	2,885	2,489
Accrued severance	2,075	1,524
Sales and franchise taxes	856	565
Outside services	1,622	2,063
Litigation matters (Note 15)	12,500	0
Acculis recall liability	2,563	0
Other	4,920	5,887
Total	$ 38,804	$ 21,942

Accrued Liabilities Accrued Liabilites (Details) (Textual) $ in Millions	3 Months Ended
	May 31, 2017 USD ($)
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Recall period	2 years
Disposal group, deferral of revenue	$ 2.6
Disposal group, increase in inventory and hardware asset reserve	2.6
Acculis Capital Systems \| Discontinued Operations, Disposed of by Means Other than Sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal group, impact to income	$ 4.5

Long-Term Debt (Details1) - USD ($) $ in Thousands	May 31, 2017	May 31, 2016
Future minimum principal payments on long-term debt
Long-term Debt, Gross	$ 97,500
Debt Instrument, Unamortized Discount (Premium), Net	(1,180)
Bank Notes	96,320
Long-term Debt, Current Maturities	(5,000)	$ (16,250)
Long-term Debt, Excluding Current Maturities	91,320
Secured Debt \| Line of Credit
Future minimum principal payments on long-term debt
2018	5,000
2019	5,000
2020	7,500
2021	11,250
2022	68,750
Long-term Debt, Gross	97,500
Revolving Credit Facility \| Line of Credit
Future minimum principal payments on long-term debt
Long-term Debt, Gross	$ 0

Long-Term Debt (Details Textual) - USD ($)		12 Months Ended
Long-Term Debt (Details Textual) - USD ($)	Nov. 07, 2016	May 31, 2017	May 31, 2016	May 31, 2015
Debt Instrument [Line Items]
Proceeds from issuance of and borrowings on long-term debt		$ 116,471,000	$ 0	$ 15,000,000
Repayment of long-term debt		$ (140,381,000)	$ (16,250,000)	$ (20,000,000)
JPMorgan Chase Bank, N.A., Bank of America, N.A., Keybank National Association \| Line of Credit
Debt Instrument [Line Items]
Debt instrument, term	5 years
State interest rate		2.55%
Percentage of increase in interest	2.00%
Debt instrument, maximum leverage ratio of total indebtedness to adjusted EBITDA	3.5
Debt instrument, maximum leverage ratio of total indebtedness to adjusted EBITDA, following material acquisitions	3.75
Ratio for debt service coverage	1.25
JPMorgan Chase Bank, N.A., Bank of America, N.A., Keybank National Association \| Maximum \| Line of Credit
Debt Instrument [Line Items]
Commitment fee percentage	0.35%
JPMorgan Chase Bank, N.A., Bank of America, N.A., Keybank National Association \| Minimum \| Line of Credit
Debt Instrument [Line Items]
Commitment fee percentage	0.20%
JPMorgan Chase Bank, N.A., Bank of America, N.A., Keybank National Association \| Secured Debt \| Line of Credit
Debt Instrument [Line Items]
Credit facility borrowing capacity	$ 100,000,000
Proceeds from issuance of and borrowings on long-term debt	100,000,000
JPMorgan Chase Bank, N.A., Bank of America, N.A., Keybank National Association \| Letter of Credit \| Line of Credit
Debt Instrument [Line Items]
Credit facility borrowing capacity	20,000,000
JPMorgan Chase Bank, N.A., Bank of America, N.A., Keybank National Association \| Bridge Loan \| Line of Credit
Debt Instrument [Line Items]
Credit facility borrowing capacity	5,000,000
JPMorgan Chase Bank, N.A., Bank of America, N.A., Keybank National Association \| Revolving Credit Facility \| Line of Credit
Debt Instrument [Line Items]
Credit facility borrowing capacity	150,000,000
Proceeds from issuance of and borrowings on long-term debt	16,500,000
Former Credit Agreement \| JPMorgan Chase Bank, N.A., Bank of America, N.A., Keybank National Association \| Line of Credit
Debt Instrument [Line Items]
Repayment of long-term debt	$ (116,500,000)
Base Rate \| JPMorgan Chase Bank, N.A., Bank of America, N.A., Keybank National Association \| Maximum \| Line of Credit
Debt Instrument [Line Items]
State interest rate	1.25%
Base Rate \| JPMorgan Chase Bank, N.A., Bank of America, N.A., Keybank National Association \| Minimum \| Line of Credit
Debt Instrument [Line Items]
State interest rate	0.50%
Eurodollar \| JPMorgan Chase Bank, N.A., Bank of America, N.A., Keybank National Association \| Maximum \| Line of Credit
Debt Instrument [Line Items]
State interest rate	2.25%
Eurodollar \| JPMorgan Chase Bank, N.A., Bank of America, N.A., Keybank National Association \| Minimum \| Line of Credit
Debt Instrument [Line Items]
State interest rate	1.50%

Stockholders' Equity (Details) $ / shares in Units, $ in Thousands	12 Months Ended
	May 31, 2017 USD ($) $ / shares shares
Schedule summarizes stock option activity
Shares Outstanding at beginning of year \| shares	2,281,618
Shares Granted \| shares	667,691
Shares Exercised \| shares	(826,286)
Shares Forfeited \| shares	(342,924)
Shares Expired \| shares	(112,656)
Shares Outstanding at end of year \| shares	1,667,443
Shares Options exercisable at year end \| shares	659,463
Shares Option expected to vest in future periods \| shares	884,906
Weighted Average exercise price, Outstanding at beginning of year \| $ / shares	$ 14.45
Weighted Average exercise price Granted \| $ / shares	16.83
Weighted Average exercise price Exercised \| $ / shares	13.45
Weighted Average exercise price Forfeited \| $ / shares	16.03
Weighted Average exercise price Expired \| $ / shares	19.08
Weighted Average exercise price, Outstanding at end of year \| $ / shares	15.01
Weighted Average exercise price, Options exercisable at year end \| $ / shares	14.26
Weighted Average exercise price, Options expected to vest in future periods \| $ / shares	$ 15.50
Weighted Average remaining contractual life	4 years 7 months 28 days
Weighted Average remaining contractual life, Option exercisable at year end	2 years 10 months 17 days
Weighted Average remaining contractual life, Option expected to vest in future periods	5 years 9 months 29 days
Aggregate intrinsic value, Outstanding at end of year \| $	$ 1,513
Aggregate intrinsic value, Options exercisable at year end \| $	913
Aggregate intrinsic value, Option expected to vest in future periods \| $	$ 527

Stockholders' Equity (Details 2) - $ / shares	12 Months Ended
Stockholders' Equity (Details 2) - $ / shares	May 31, 2017	May 31, 2016	May 31, 2015
Share Based Compensation Arrangement by Share Based Payment Award Nonvested Shares and Weighted Average Grant Date Fair Value [Abstract]
Weighted Average Grant-Date Fair Value, Granted		$ 15.21	$ 14.75
Restricted Stock Units
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	549,777
Non-Vested Stock Award Units, Granted	255,032
Non-Vested Stock Award Units, Cancelled	(182,320)
Non-Vested Stock Award Units, Vested	(183,192)
Non-Vested Stock Award Units Ending Balance	439,297	549,777
Weighted Average Grant-Date Fair Value Beginning Balance	$ 14.62
Weighted Average Grant-Date Fair Value, Granted	16.54
Weighted Average Grant-Date Fair Value, Cancelled	16.10
Weighted Average Grant-Date Fair Value, Vested	15.95
Weighted Average Grant-Date Fair Value Ending Balance	$ 15.55	$ 14.62
Performance Shares
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	435,892
Non-Vested Stock Award Units, Granted	93,400
Non-Vested Stock Award Units, Cancelled	(37,184)
Non-Vested Stock Award Units, Vested	(130,944)
Non-Vested Stock Award Units Ending Balance	361,164	435,892
Weighted Average Grant-Date Fair Value Beginning Balance	$ 19.16
Weighted Average Grant-Date Fair Value, Granted	22.61
Weighted Average Grant-Date Fair Value, Cancelled	14.48
Weighted Average Grant-Date Fair Value, Vested	21.54
Weighted Average Grant-Date Fair Value Ending Balance	$ 18.54	$ 19.16

Stockholders' Equity (Details 3) - USD ($) $ in Thousands	12 Months Ended
Stockholders' Equity (Details 3) - USD ($) $ in Thousands	May 31, 2017	May 31, 2016	May 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock based compensation pre tax amount	$ 6,183	$ 3,240	$ 5,998
Cost of Sales
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock based compensation pre tax amount	299	172	143
Research and Development
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock based compensation pre tax amount	314	349	229
Sales and Marketing
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock based compensation pre tax amount	1,762	1,489	1,685
General and Administrative Expense
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock based compensation pre tax amount	4,026	2,291	3,941
Acquisition, Restructuring And Other Items, Net
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock based compensation pre tax amount	$ (218)	$ (1,061)	$ 0

Stockholders' Equity (Details Textual)					1 Months Ended	3 Months Ended		12 Months Ended
Stockholders' Equity (Details Textual)	Nov. 06, 2016 USD ($)	May 31, 2016 $ / shares shares	Oct. 29, 2014 $ / shares shares	Oct. 05, 2011 shares	Feb. 28, 2017 USD ($) $ / shares shares	May 31, 2017 USD ($) $ / shares shares	Nov. 30, 2016 USD ($) shares	May 31, 2017 USD ($) working_hour Employees $ / shares shares	May 31, 2016 USD ($) $ / shares shares	May 31, 2015 USD ($) $ / shares shares
Other Ownership Interests [Line Items]
Dividends \| $								$ 0	$ 0	$ 0
Employee Service Share-based Compensation, Tax Benefit from Compensation Expense \| $								$ 2,200,000	$ 1,000,000	$ 2,000,000
Authorized capital stock			80,000,000
Shares of common stock (shares)		75,000,000	75,000,000			75,000,000		75,000,000	75,000,000
Common stock, par value (usd per share) \| $ / shares		$ 0.01	$ 0.01		$ 0.01	$ 0.01		$ 0.01	$ 0.01
Preferred stock, shares authorized (shares)		5,000,000	5,000,000			5,000,000		5,000,000	5,000,000
Preferred stock, par value (usd per share) \| $ / shares		$ 0.01	$ 0.01			$ 0.01		$ 0.01	$ 0.01
Common stock, votes per share			1
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
Option grants in the period, weighted average grant date fair value (usd per share) \| $ / shares								$ 4.70	$ 4.16	$ 4.74
Risk free interest rate								1.30%	1.48%	1.54%
Expected volatility rate								31.00%	31.00%	31.00%
Expected term								4 years 9 months 20 days	4 years 9 months 21 days	4 years 9 months 3 days
The total intrinsic value of options exercised \| $								$ 2,800,000	$ 100,000	$ 1,600,000
Compensation not yet recognized \| $						$ 3,700,000		3,700,000
Proceeds from stock options exercised \| $								9,900,000	1,300,000	4,300,000
Stock based compensation pre tax amount \| $								$ 6,183,000	$ 3,240,000	$ 5,998,000
Grants in the period, weighted average grant date fair value (usd per share) \| $ / shares									$ 15.21	$ 14.75
Average price of share issued \| $ / shares		$ 10.67				$ 11.00		$ 11.00	$ 10.67	$ 11.89
Shares awarded (shares)								667,691
Treasury Stock, Value, Acquired, Cost Method \| $								$ 13,557,000
Repurchase of common stock \| $						$ 5,700,000		13,557,000	$ 0	$ 0
Performance Share and Restricted Stock Unit Awards
Other Ownership Interests [Line Items]
Total fair value of restricted stock awards vesting \| $								2,900,000	$ 2,500,000	$ 2,400,000
Restricted Stock
Other Ownership Interests [Line Items]
Period of recognition for costs not yet recognized		3 years
Employee service, compensation cost not yet recognized \| $						4,900,000		4,900,000
Performance Shares
Other Ownership Interests [Line Items]
Employee service, compensation cost not yet recognized \| $						$ 4,200,000		$ 4,200,000
Nonvested compensation, weighted average grant date fair valur (usd per share) \| $ / shares		$ 18.07				$ 22.61		$ 22.61	$ 18.07	$ 19.83
Performance period								3 years
Nonvested compensation (shares)						400,000		400,000
Weighted average remaining contractual term								3 years
Restricted Stock Units
Other Ownership Interests [Line Items]
Grants in the period, weighted average grant date fair value (usd per share) \| $ / shares								$ 16.54
Nonvested compensation, weighted average grant date fair valur (usd per share) \| $ / shares		$ 14.62				$ 15.55		$ 15.55	$ 14.62
Nonvested compensation (shares)		549,777				439,297		439,297	549,777
Employee Stock Option
Other Ownership Interests [Line Items]
Stock based compensation pre tax amount \| $								$ 0	$ 100,000	$ 500,000
Employee Stock Option
Other Ownership Interests [Line Items]
Period of recognition for costs not yet recognized								3 years
2004 Stock and Incentive Award Plan
Other Ownership Interests [Line Items]
Total number of common stock available to be issued						2,400,000		2,400,000
Total number of common stock reserved for issuance						7,000,000		7,000,000
Options exercisable period								10 years
Incentive award plan to increase the minimum number of shares				250,000
2004 Stock and Incentive Award Plan \| Maximum
Other Ownership Interests [Line Items]
Total number of common stock available to be issued						800,000		800,000
Stock Purchase Plan
Other Ownership Interests [Line Items]
Total number of common stock available to be issued						1,300,000.0		1,300,000.0
Share purchase periods \| Employees								2
Duration of purchase of shares								6 months
Employee eligible in participating in offering period								6 months
Maximum number of shares to be offered						2,500,000		2,500,000
Working schedule of employee to participate in offering period								20 or more hours per week and more than five months in a calendar year
Number of working hours to be eligible (working hour) \| working_hour								20
Number of working months to be eligible								5 months
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%
Number of additional shares reserved for issuance (shares)								500,000		800,000
Maximum number of shares to be offered under the Stock Purchase Plan								129,185	137,957	119,001
Common Stock
Other Ownership Interests [Line Items]
Treasury Stock, Shares, Acquired							500,000
Treasury Stock, Value, Acquired, Cost Method \| $							$ 7,800,000
Stock Repurchased During Period, Shares						370,000
Stock Repurchase Program, Remaining Authorized Repurchase Amount \| $						$ 11,400,000		$ 11,400,000
Stock Repurchase Program, Authorized Amount \| $	$ 25,000,000
Stock Repurchase Program, Period in Force	24 months
Common Stock
Other Ownership Interests [Line Items]
Maximum number of shares to be offered under the Stock Purchase Plan								129,185	137,957	119,001
Treasury Stock, Shares, Acquired								370,000
Treasury Stock, Value, Acquired, Cost Method \| $								$ (3,000)
Treasury Stock, Shares, Retired					642,305			(642,305)
Treasury Stock, Retired, Par Value Method, Amount \| $					$ 9,900,000			$ (2,000)

Earnings Per Share (Details) - shares	12 Months Ended
Earnings Per Share (Details) - shares	May 31, 2017	May 31, 2016	May 31, 2015
Earnings Per Share [Abstract]
Basic weighted average shares outstanding (in shares)	36,616,859	36,161,383	35,683,139
Effect of dilutive securities (shares)	342,391	0	0
Diluted weighted average shares outstanding (in shares)	36,959,250	36,161,383	35,683,139
Securities excluded as their inclusion would be anti-dilutive (shares)	1,058,790	3,277,037	2,862,414

Commitments and Contingencies (Details) $ in Thousands	May 31, 2017 USD ($)
Aggregate of future annual payments under non cancelable operating leases for facilities and equipment [Abstract]
2015	$ 2,214
2016	2,066
2017	1,860
2018	1,025
2019	2,552
Total	$ 9,717

Commitments and Contingencies Commitments and Contingencies (Details 1) $ in Thousands	May 31, 2017 USD ($)
Commitments and Contingencies Disclosure [Abstract]
Purchase obligation	$ 49,762
Purchase obligation, 2018	8,443
Purchase obligation, 2019	8,726
Purchase obligation, 2020	9,162
Purchase obligation, 2021	8,709
Purchase obligation, 2022 and thereafter	14,722
Royalties	44,000
Royalties, 2018	2,500
Royalties, 2019	3,000
Royalties, 2020	3,500
Royalties, 2021	3,500
Royalties, 2022 and thereafter	31,500
Other	834
Other, 2018	167
Other, 2019	167
Other, 2020	167
Other, 2021	167
Other, 2022 and thereafter	166
Total	94,596
Total, 2018	11,110
Total, 2019	11,893
Total, 2020	12,829
Total, 2021	12,376
Total, 2022 and thereafter	$ 46,388

Commitments and Contingencies (Details Textual) $ in Millions							9 Months Ended	12 Months Ended
	Mar. 29, 2016 claim	Mar. 24, 2016 claim	Mar. 11, 2016 claim	Jun. 01, 2015 motion	Mar. 10, 2015 patent	Jan. 11, 2012 reexamination_appeal patent claim	Feb. 28, 2017 Petition reexamination_appeal	May 31, 2017 USD ($)	May 31, 2016 USD ($)	May 31, 2015 USD ($)
Commitments and Contingencies (Textual) [Abstract]
Aggregate rental costs under operating leases \| $								$ 2.5	$ 2.5	$ 3.4
Reserve \| $								$ 12.5
C.R. Bard, Inc.
Loss Contingencies [Line Items]
Loss Contingency, U.S. Patents, Number \| patent						3
Cr Bard Inc
Commitments and Contingencies (Textual) [Abstract]
Number of petitions filed for reexamination of patents \| Petition							3
The Utah Action
Commitments and Contingencies (Textual) [Abstract]
Number of claims rejected (claim)	20	8	6			40
Number of reexaminations (reexamination appeal) \| reexamination_appeal						3
Number of pending claims (claim)		10	10
Number of claims reversed (claim)		2	4
Loss contingency, new claims filed, number						41
The Delaware Action
Commitments and Contingencies (Textual) [Abstract]
Number of patents allegedly infringed (patent)				2	3
Pending Litigation \| The Utah Action
Commitments and Contingencies (Textual) [Abstract]
Number of reexaminations (reexamination appeal) \| reexamination_appeal							2
C.R. Bard, Inc. \| Pending Litigation \| The Utah Action
Commitments and Contingencies (Textual) [Abstract]
Number of reexaminations (reexamination appeal) \| reexamination_appeal							3

Segments and Geographic Information (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	May 31, 2017	Feb. 28, 2017	Nov. 30, 2016	Aug. 31, 2016	May 31, 2016	Feb. 29, 2016	Nov. 30, 2015	Aug. 31, 2015	May 31, 2017	May 31, 2016	May 31, 2015
Summary of total net sales by product category
Net sales	$ 86,914	$ 85,602	$ 89,029	$ 88,098	$ 93,419	$ 87,434	$ 89,284	$ 83,753	$ 349,643	$ 353,890	$ 356,534
Peripheral Vascular
Summary of total net sales by product category
Net sales									208,602	205,620	196,890
Vascular Access
Summary of total net sales by product category
Net sales									96,481	99,375	107,754
Oncology/Surgery
Summary of total net sales by product category
Net sales									$ 44,560	$ 48,895	$ 51,890

Segments and Geographic Information (Details 1) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	May 31, 2017	Feb. 28, 2017	Nov. 30, 2016	Aug. 31, 2016	May 31, 2016	Feb. 29, 2016	Nov. 30, 2015	Aug. 31, 2015	May 31, 2017	May 31, 2016	May 31, 2015
Net Sales by Geography
Net sales	$ 86,914	$ 85,602	$ 89,029	$ 88,098	$ 93,419	$ 87,434	$ 89,284	$ 83,753	$ 349,643	$ 353,890	$ 356,534
United States
Net Sales by Geography
Net sales									282,168	285,824	284,122
International
Net Sales by Geography
Net sales									$ 67,475	$ 68,066	$ 72,412

Segments and Geographic Information (Details Textual) - Segment	12 Months Ended
	May 31, 2017	May 31, 2016	May 31, 2015
Segment Reporting [Abstract]
International sales percentage of total net sales	19.00%	19.00%	20.00%
Number of segment (segment)	1
Total assets are located within the United States	99.00%

Acquisition, Restructuring and Other Items, net (Details) - USD ($)	12 Months Ended
	May 31, 2017	May 31, 2016	May 31, 2015
Restructuring Cost and Reserve [Line Items]
Acquisition Restructuring and Other Items Net	$ 27,510,000	$ 12,591,000	$ 26,257,000
Restructuring Reserve	12,500,000	0
Restructuring Charges	1,348,000	0
Legal Costs [Member]
Restructuring Cost and Reserve [Line Items]
Acquisition Restructuring and Other Items Net	19,480,000	$ 7,487,000	$ 4,959,000
Accrued Expenses
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve	962,000
Manchester, GA and Denmead, UK into Glens Falls and Queensbury, NY [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	$ 1,300,000

Acquisition, Restructuring and Other Items, net (Details 1) - USD ($) $ in Thousands	12 Months Ended
	May 31, 2017	May 31, 2016	May 31, 2015
Restructuring Cost and Reserve [Line Items]
Acquisition Restructuring and Other Items Net	$ 27,510	$ 12,591	$ 26,257
Legal Costs [Member]
Restructuring Cost and Reserve [Line Items]
Acquisition Restructuring and Other Items Net	19,480	7,487	4,959
Intangible Impairment [Member]
Restructuring Cost and Reserve [Line Items]
Acquisition Restructuring and Other Items Net	5,604	352	15,504
Facility Closing [Member]
Restructuring Cost and Reserve [Line Items]
Acquisition Restructuring and Other Items Net	1,348	1,462	1,997
Other Restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Acquisition Restructuring and Other Items Net	$ 1,078	$ 3,290	$ 3,797

Acquisition, Restructuring and Other Items, net (Details 2) $ in Thousands	May 31, 2017 USD ($)
Minimum [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Expected Cost	$ 6,250
Minimum [Member] \| One-time Termination Benefits [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Expected Cost	1,750
Minimum [Member] \| Equipment Transfer [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Expected Cost	2,250
Minimum [Member] \| Regulatory Filings [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Expected Cost	750
Minimum [Member] \| Contract Termination [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Expected Cost	750
Minimum [Member] \| Other Restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Expected Cost	750
Maximum [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Expected Cost	7,750
Maximum [Member] \| One-time Termination Benefits [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Expected Cost	2,250
Maximum [Member] \| Equipment Transfer [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Expected Cost	2,500
Maximum [Member] \| Regulatory Filings [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Expected Cost	1,000
Maximum [Member] \| Contract Termination [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Expected Cost	1,000
Maximum [Member] \| Other Restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Expected Cost	$ 1,000

Acquisition, Restructuring and Other Items, net (Details 3) - USD ($)	12 Months Ended
	May 31, 2017	May 31, 2016
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve, beginning of period	$ 0
Restructuring Charges	1,348,000	$ 0
Restructuring Reserve, Settled without Cash	(108,000)
Payments for Restructuring	(278,000)
Restructuring Reserve, end of period	12,500,000	0
One-time Termination Benefits [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve, beginning of period	0
Restructuring Charges	851,000
Restructuring Reserve, Settled without Cash	0
Payments for Restructuring	0
Restructuring Reserve, end of period	851,000	0
Equipment Transfer [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve, beginning of period	0
Restructuring Charges	494,000
Restructuring Reserve, Settled without Cash	(108,000)
Payments for Restructuring	(275,000)
Restructuring Reserve, end of period	111,000	0
Regulatory Filings [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve, beginning of period	0
Restructuring Charges	0
Restructuring Reserve, Settled without Cash	0
Payments for Restructuring	0
Restructuring Reserve, end of period	0	0
Contract Termination [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve, beginning of period	0
Restructuring Charges	0
Restructuring Reserve, Settled without Cash	0
Payments for Restructuring	0
Restructuring Reserve, end of period	0	0
Other Restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve, beginning of period	0
Restructuring Charges	3,000
Restructuring Reserve, Settled without Cash	0
Payments for Restructuring	(3,000)
Restructuring Reserve, end of period	0	$ 0
Accrued Expenses
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve, end of period	$ 962,000

Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	12 Months Ended
	May 31, 2017	May 31, 2016	May 31, 2015
Class of Stock [Line Items]
Beginning Balance	$ 507,228	$ 545,099	$ 536,885
Total comprehensive income (loss), net of tax	4,475	(43,548)	(3,540)
Ending Balance	515,027	507,228	545,099
Foreign currency translation gain (loss)
Class of Stock [Line Items]
Beginning Balance	(760)	(648)
Other comprehensive income (loss) before reclassifications	(545)	(112)
Amounts reclassified from accumulated other comprehensive income	0	0
Total comprehensive income (loss), net of tax	(545)	(112)
Ending Balance	(1,305)	(760)	(648)
Unrealized gain (loss) on marketable securities
Class of Stock [Line Items]
Beginning Balance	(31)	(23)
Other comprehensive income (loss) before reclassifications	12	(8)
Amounts reclassified from accumulated other comprehensive income	0	0
Total comprehensive income (loss), net of tax	12	(8)
Ending Balance	(19)	(31)	(23)
Unrealized gain (loss) on interest rate swap
Class of Stock [Line Items]
Beginning Balance	0	(162)
Other comprehensive income (loss) before reclassifications	0	162
Amounts reclassified from accumulated other comprehensive income	0	0
Total comprehensive income (loss), net of tax	0	162
Ending Balance	0	0	(162)
AOCI Attributable to Parent [Member]
Class of Stock [Line Items]
Beginning Balance	(791)	(833)	(681)
Other comprehensive income (loss) before reclassifications	(533)	42
Amounts reclassified from accumulated other comprehensive income	0	0
Total comprehensive income (loss), net of tax	(533)	42
Ending Balance	$ (1,324)	$ (791)	$ (833)

Quarterly Information (unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	May 31, 2017	Feb. 28, 2017	Nov. 30, 2016	Aug. 31, 2016	May 31, 2016	Feb. 29, 2016	Nov. 30, 2015	Aug. 31, 2015	May 31, 2017	May 31, 2016	May 31, 2015
Quarterly Financial Information Disclosure [Abstract]
Estimated Litigation Liability					$ 12,500					$ 12,500
Summary of Quarterly Financial Information
Net sales	$ 86,914	$ 85,602	$ 89,029	$ 88,098	$ 93,419	$ 87,434	$ 89,284	$ 83,753	$ 349,643	$ 353,890	$ 356,534
Earnings per common share
Basic (usd per share)	$ (0.35)	$ 0.08	$ 0.37	$ 0.04	$ (1.19)	$ 0.02	$ (0.01)	$ (0.02)	$ 0.14	$ (1.21)	$ (0.09)
Diluted (usd per share)	$ (0.35)	$ 0.08	$ 0.37	$ 0.04	$ (1.19)	$ 0.02	$ (0.01)	$ (0.02)	$ 0.14	$ (1.21)	$ (0.09)

Quarterly Information - Quarterly Information (Details 2) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	May 31, 2017	Feb. 28, 2017	Nov. 30, 2016	Aug. 31, 2016	May 31, 2016	Feb. 29, 2016	Nov. 30, 2015	Aug. 31, 2015	May 31, 2017	May 31, 2016	May 31, 2015
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net sales	$ 86,914	$ 85,602	$ 89,029	$ 88,098	$ 93,419	$ 87,434	$ 89,284	$ 83,753	$ 349,643	$ 353,890	$ 356,534
Gross profit	42,335	43,792	45,010	45,032	41,527	43,534	45,884	43,371	176,169	174,316	175,796
Net income (loss)	(12,913)	$ 2,887	$ 13,734	$ 1,300	$ (43,075)	$ 594	$ (334)	$ (775)	$ 5,008	(43,590)	$ (3,388)
Deferred Tax Assets, Valuation Allowance										$ 40,400
Discontinued Operations, Disposed of by Means Other than Sale \| Acculis Capital Systems
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal group, impact to income	$ 4,500

Valuation and Qualifying Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	May 31, 2017	May 31, 2016	May 31, 2015
Allowance for deferred tax asset
Valuation and Qualifying Accounts
Balance at Beginning of Year	$ 42,209	$ 1,791	$ 1,531
Additions - Charged to costs and expenses	6,139	40,685	467
Deductions	0	(267)	(207)
Balance at End of Period	48,348	42,209	1,791
Allowance for sales returns and doubtful accounts
Valuation and Qualifying Accounts
Balance at Beginning of Year	4,372	3,043	1,736
Additions - Charged to costs and expenses	(291)	3,748	1,846
Deductions	(1,136)	(2,419)	(539)
Balance at End of Period	$ 2,945	$ 4,372	$ 3,043

Retirement Plans	12 Months Ended
Retirement Plans	May 31, 2017
Retirement Benefits [Abstract]
RETIREMENT PLANS	RETIREMENT PLANS The Company has a 401(k) plan under which eligible employees can defer a portion of their compensation, part of which is matched by the Company. Matching contributions were $4.2 million, $3.7 million and $3.7 million in 2017, 2016 and 2015, respectively. There are also various immaterial foreign retirement plans.

Retirement Plans (Details) - USD ($) $ in Millions	12 Months Ended
Retirement Plans (Details) - USD ($) $ in Millions	May 31, 2017	May 31, 2016	May 31, 2015
Retirement Plans (Textual) [Abstract]
Matching contributions	$ 4.2	$ 3.7	$ 3.7

Label	Element	Value
Additional Paid-in Capital [Member]
Treasury Stock, Retired, Par Value Method, Amount	us-gaap_TreasuryStockRetiredParValueMethodAmount	$ 9,900,000