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Document and Entity Information - USD ($)	12 Months Ended
Document and Entity Information - USD ($)	May 31, 2018	Jul. 20, 2018	Nov. 30, 2017
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, 2018
Amendment Flag	false
Document Fiscal Year Focus	2018
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			$ 631,826,627
Entity Common Stock, Shares Outstanding		36,885,765

Consolidated Statements of Operations - USD ($) $ in Thousands	12 Months Ended
	May 31, 2018	May 31, 2017	May 31, 2016
Income Statement [Abstract]
Net sales	$ 344,285	$ 349,643	$ 353,890
Cost of sales (exclusive of intangible amortization)	167,410	173,474	179,574
Gross profit	176,875	176,169	174,316
Operating expenses
Research and development	25,459	25,269	25,053
Sales and marketing	77,276	78,819	83,743
General and administrative	31,265	31,406	30,583
Amortization of intangibles	16,635	17,296	17,964
Change in fair value of contingent consideration	250	(15,261)	948
Acquisition, restructuring and other items, net	15,432	27,510	12,591
Medical device excise tax	0	(1,837)	2,416
Total operating expenses	166,317	163,202	173,298
Operating income	10,558	12,967	1,018
Other expenses
Interest expense, net	(3,062)	(2,839)	(3,385)
Other expense	(31)	(281)	(886)
Total other expenses, net	(3,093)	(3,120)	(4,271)
Income (loss) before income tax expense (benefit)	7,465	9,847	(3,253)
Income tax expense (benefit)	(8,870)	4,839	40,337
Net income (loss)	$ 16,335	$ 5,008	$ (43,590)
Earnings (loss) per share
Basic (usd per share)	$ 0.44	$ 0.14	$ (1.21)
Diluted (usd per share)	$ 0.44	$ 0.14	$ (1.21)
Weighted average shares outstanding
Basic (in shares)	37,074,797	36,616,859	36,161,383
Diluted (in shares)	37,539,400	36,959,250	36,161,383

Consolidated Statements Comprehensive Income (Loss) - USD ($) $ in Thousands	12 Months Ended
	May 31, 2018	May 31, 2017	May 31, 2016
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 16,335	$ 5,008	$ (43,590)
Other comprehensive income (loss), before tax:
Unrealized gain (loss) on marketable securities	102	12	(11)
Unrealized gain on interest rate swap	0	0	257
Foreign currency translation gain (loss)	270	(545)	(112)
Other comprehensive income (loss), before tax	372	(533)	134
Income tax benefit (expense) related to items of other comprehensive income (loss)	0	0	(92)
Other comprehensive income (loss), net of tax	372	(533)	42
Total comprehensive income (loss), net of tax	$ 16,707	$ 4,475	$ (43,548)

Consolidated Balance Sheets - USD ($) $ in Thousands	May 31, 2018	May 31, 2017
Current Assets
Cash and cash equivalents	$ 74,096	$ 47,544
Marketable securities, at fair value	1,317	1,215
Accounts receivable, net of allowances of $2,466 and $2,945, respectively	39,401	44,523
Inventories	48,916	54,506
Prepaid expenses and other	4,302	6,126
Total current assets	168,032	153,914
Property, plant and equipment, net	42,461	45,234
Other assets	3,417	1,886
Intangible assets, net	130,310	145,675
Goodwill	361,252	361,252
Total Assets	705,472	707,961
Current Liabilities
Accounts payable	15,775	18,087
Accrued liabilities	34,426	38,804
Current portion of long-term debt	5,000	5,000
Current portion of contingent consideration	2,100	9,625
Total current liabilities	57,301	71,516
Long-term debt, net of current portion	86,621	91,320
Deferred income taxes	17,173	26,112
Contingent consideration, net of current portion	1,161	3,136
Other long-term liabilities	621	850
Total Liabilities	162,877	192,934
Commitments and Contingencies (Note 15)
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; 37,594,493 and 37,210,091 shares issued and 37,224,493 and 36,840,091 shares outstanding at May 31, 2018 and 2017, respectively	370	367
Additional paid-in capital	543,762	532,705
Retained earnings (accumulated deficit)	5,129	(11,007)
Treasury stock, 370,000 shares, at cost at May 31, 2018 and 2017, respectively	(5,714)	(5,714)
Accumulated other comprehensive loss	(952)	(1,324)
Total Stockholders' Equity	542,595	515,027
Total Liabilities and Stockholders' Equity	$ 705,472	$ 707,961

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	May 31, 2018	May 31, 2017
Statement of Financial Position [Abstract]
Accounts receivable, allowances	$ 2,466	$ 2,945
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
Common stock, shares authorized (shares)	75,000,000	75,000,000
Common stock, shares issued (shares)	37,594,493	37,210,091
Common stock, shares outstanding (shares)	37,224,493	36,840,091
Treasury stock, shares (shares)	370,000	370,000

Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Restricted Stock Units	Performance Shares	Common Stock	Common Stock Restricted Stock Units	Common Stock Performance Shares	Additional paid in capital	Additional paid in capital Restricted Stock Units	Additional paid in capital Performance Shares	Retained earnings (accumulated deficit)	Accumulated other comprehensive loss	Treasury Stock
Beginning Balance at May. 31, 2015	$ 545,099			$ 360			$ 520,101			$ 27,575	$ (833)	$ (2,104)
Beginning 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/cancellation of common stock units	(331)			$ 1			(332)
Issuance/cancellation of common stock units, 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				36,420,403.000								(142,305.000)
Net income	5,008									5,008
Exercise of stock options	9,865			$ 7			9,858
Exercise of stock options, Shares				751,062
Issuance/cancellation of common stock units		$ (586)	$ 0		$ 1	$ 0		$ (587)	$ 0
Issuance/cancellation of common stock units, 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						6,183
Treasury stock retirement	0			$ (2)			(9,942)					$ 9,944
Treasury stock retirement, Shares				(642,305)								642,305
Common stock repurchased	(13,557)			$ 3								$ (13,554)
Common stock repurchased, Shares				(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
Adjustment for ASU 2016-09	0						199			(199)
Net income	16,335									16,335
Exercise of stock options	$ 1,917			$ 1			1,916
Exercise of stock options, Shares	271,344			148,937
Issuance/cancellation of common stock units		$ (231)			$ 1			$ (232)
Issuance/cancellation of common stock units, Shares					145,522
Purchase of common stock under Employee Stock Purchase Plan	$ 1,263			$ 1			1,262
Purchase of common stock under Employee Stock Purchase Plan, Shares				89,943
Stock-based compensation	7,912						7,912
Other comprehensive income (loss), net of tax	372										372
Ending Balance at May. 31, 2018	$ 542,595			$ 370			$ 543,762			$ 5,129	$ (952)	$ (5,714)
Ending Balance, Shares at May. 31, 2018				37,594,493								370,000

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	May 31, 2018	May 31, 2017	May 31, 2016
Cash flows from operating activities:
Net income (loss)	$ 16,335	$ 5,008	$ (43,590)
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation and amortization	23,163	24,811	28,115
Stock based compensation	7,912	6,183	3,240
Change in fair value of contingent consideration	250	(15,261)	948
Deferred income tax provision	(8,947)	4,428	39,983
Changes in accounts receivable allowances	179	(313)	2,377
Fixed and intangible asset impairments and disposals	540	3,930	1,190
Write-off of other assets	0	2,685	0
Other	(605)	(586)	90
Changes in operating assets and liabilities:
Accounts receivable	5,044	8,479	3,131
Inventories	5,740	687	11,976
Prepaid expenses and other	(1,231)	(3,520)	712
Accounts payable, accrued and other liabilities	(7,093)	19,214	(2,956)
Net cash provided by operating activities	41,287	55,745	45,216
Cash flows from investing activities:
Additions to property, plant and equipment	(2,391)	(3,001)	(2,326)
Acquisition of intangibles	(1,265)	0	(3,268)
Acquisition of warrants	0	0	(2,000)
Proceeds from sale or maturity of marketable securities	0	450	25
Net cash used in investing activities	(3,656)	(2,551)	(7,569)
Cash flows from financing activities:
Proceeds from issuance of and borrowings on long-term debt	0	116,471	0
Repayment of long-term debt	(5,000)	(140,381)	(16,250)
Deferred financing costs on long-term debt	0	(1,364)	0
Payment of acquisition related contingent consideration	(9,500)	(9,850)	(9,850)
Repurchase of common stock	0	(13,557)	0
Proceeds from exercise of stock options and employee stock purchase plan	2,949	10,698	2,437
Net cash used in financing activities	(11,551)	(37,983)	(23,663)
Effect of exchange rate changes on cash and cash equivalents	472	0	(42)
Increase in cash and cash equivalents	26,552	15,211	13,942
Cash and cash equivalents at beginning of year	47,544	32,333	18,391
Cash and cash equivalents at end of year	74,096	47,544	32,333
Supplemental disclosure of non-cash investing and financing activities:
Contractual obligations for purchase of fixed assets	56	26	75
Cash paid (received) during the year for:
Interest	3,190	2,969	3,063
Income taxes	$ 36	$ (102)	$ 332

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

12 Months Ended

May 31, 2018

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.

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 an investment 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, 2018 and 2017, the Company had $1.3 million and $1.2 million, respectively, in an auction rate security issued by a local government authority. The authority is current in its interest payments on the security.

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		5 to 8 years
Computer software and equipment		3 to 5 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, 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 reviews such assets for impairment whenever events or changes in circumstances indicate that the carrying value of the asset or asset group is not 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 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 fair value through an adjustment to the goodwill balance, resulting in an impairment charge.

The Company's annual testing for impairment of goodwill was completed as of December 31, 2017. 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.

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 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.

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.

The following table provides a description of recent accounting pronouncements that may have a material effect on the Company's consolidated financial statements:



Recently Issued Accounting Pronouncements - Adopted
Standard	Description	Date Adopted	Effect on the Consolidated Financial Statements
ASU 2016-09, Compensation - Stock Based Compensation (Topic 718: Improvements to Employee Share-Based Payment Accounting)	This ASU 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.	June 1, 2017	The Company now recognizes unrealized excess tax benefits and will classify such benefits as an operating activity in the statement of cash flows on a prospective basis. Due to the full valuation allowance on our federal and state income taxes, the adoption of ASU 2016-09 did not impact our accounting for income taxes.
			The Company elected the accounting policy change to account for forfeitures as they occur. This was adopted using the modified retrospective transition method by means of a cumulative-effect adjustment to equity as of June 1, 2017. The adoption of ASU 2016-09 did not materially impact the Company's consolidated statements of income, consolidated balance sheet, equity or cash flows.
ASU 2017-04, Intangibles - Goodwill and Other (Topic 350)	This ASU simplifies the subsequent measurement of goodwill by eliminating steps from the goodwill impairment test.	June 1, 2017	This adoption did not have an impact on the Company's financial statements.
ASC Update No. 2015-11, Inventory (Topic 330): Simplifying the Measurement of Inventory. Update No. 2015-11	This ASU 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.	June 1, 2017	This adoption did not have an impact on the Company's financial statements.



Recently Issued Accounting Pronouncements - Not Yet Applicable or Adopted
Standard	Description	Effective Date	Effect on the Consolidated Financial Statements
ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606, ASU 2014-09)	Under Topic 606, an entity is required to recognize revenue upon transfer of promised goods or services to customers in an amount that reflects the expected consideration to be received in exchange for those goods or services. Topic 606 defines a five-step process in order to achieve this core principle, which may require the use of judgment and estimates, and also requires expanded qualitative and quantitative disclosures relating to the nature, amount, timing and uncertainty of revenue and cash flows arising from contracts with customers, including significant judgments and estimates used. The new standard also defines accounting for certain costs related to origination and fulfillment of contracts with customers, including whether such costs should be capitalized.	June 1, 2018	The Company established an implementation team which included third-party specialists to assist in the evaluation and implementation of the new standard. The Company’s assessment has included performing analysis for each revenue stream identified, assessing the potential differences in recognition and measurement that may result from adopting this standard and assessing whether the Company meets certain practical expedients. Based on the results of the assessment, the adoption of this standard will not have a material impact on the timing or amount of revenue recognized upon adoption and there is no cumulative prior period adjustment to be recorded to the opening balance of retained earnings upon adoption. The Company will adopt the standard using the modified retrospective method. The Company is implementing changes to accounting policies, business processes and internal controls to support the new standard as necessary. Upon adoption of Topic 606, as the disclosure requirements under the new guidance have been significantly expanded in comparison to the disclosure requirements under the current guidance, we will provide additional disclosures in the notes to the consolidated financial statements, specifically related to performance obligations, the judgments made in revenue recognition determinations, costs to obtain or fulfill contracts and contract balances.
ASU No. 2016-15, Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments (ASU 2016-15)	This ASU identifies how certain cash receipts and cash payments are presented and classified in the Statement of Cash Flows under Topic 230.	June 1, 2018	This adoption is not expected to have a material impact on the Company's financial statements.
ASU 2016-02, Leases (Topic 842)	This ASU 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 of 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.	June 1, 2019	The Company is currently in the process of evaluating the impact of this ASU on its consolidated financial statements.

Other Assets	12 Months Ended
Other Assets	May 31, 2018
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, 2018

Fair Value Disclosures [Abstract]

FAIR VALUE OF FINANCIAL INSTRUMENTS

On a recurring basis, the Company measures certain financial assets and financial liabilities at fair value based upon quoted market prices, where available. Where quoted market prices or other observable inputs are not available, the Company applies valuation techniques to estimate fair value. FASB ASC Topic 820, Fair Value Measurements and Disclosures, establishes a three-level valuation hierarchy for disclosure of fair value measurements. The categorization of financial assets and financial liabilities within the valuation hierarchy is based upon the lowest level of input that is significant to the measurement of fair value. The three levels of the hierarchy are defined as follows:


•	Level 1 - Inputs to the valuation methodology are quoted market prices for identical assets or liabilities.


•	Level 2 - Inputs to the valuation methodology are other observable inputs, including quoted market prices for similar assets or liabilities and market-corroborated inputs.


•	Level 3 - Inputs to the valuation methodology are unobservable inputs based on management’s best estimate of inputs market participants would use in pricing the asset or liability at the measurement date, including assumptions about risk.

The Company's financial instruments include cash and cash equivalents, marketable securities, accounts receivable, accounts payable and contingent consideration. The carrying amount of cash and cash equivalents, accounts receivable, and accounts payable approximates fair value due to their immediate or short-term maturities. The recurring fair value measurements using significant unobservable inputs (Level 3) relate to marketable securities, which are comprised of auction rate securities, and contingent consideration liabilities.

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, 2018
Financial Assets
Short-term investments*	$	2,100	$	—	$	—	$	2,100
Marketable securities	—		—		1,317		1,317
Total Financial Assets	$	2,100	$	—	$	1,317	$	3,417
Financial Liabilities
Contingent liability for acquisition earn outs	$	—	$	—	$	3,261	$	3,261
Total Financial Liabilities	$	—	$	—	$	3,261	$	3,261

*included in cash and cash equivalents.



	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

There were no transfers in and out of Level 1, 2 and 3 measurements for the years ended May 31, 2018 and 2017.

The table below presents the changes in fair value components of Level 3 instruments in the year ended May 31, 2018 (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, 2017	$	1,215	$	12,761
Change in fair value of contingent consideration, net (1)	—		250
Fair market value adjustments	102		—
Contingent consideration payments	—		(9,750		)
Balance at May 31, 2018	$	1,317	$	3,261

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 (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

(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.

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 during the second quarter of fiscal year 2017. 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 in the second quarter of fiscal year 2017 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.

Short-term Investments

Short-term investments consist of highly liquid investments in municipal bonds that reset on a weekly basis and can be called at any point in time.

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

Some of our business combinations involve the potential for the payment of future contingent consideration upon the achievement of certain product development milestones or various other performance conditions. Payment of the additional consideration is generally contingent on the acquired company reaching certain performance milestones, including attaining specified revenue levels or product development targets. Contingent consideration is recorded at the estimated fair value of the contingent payments on the acquisition date. The fair value of the contingent 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 statements of income.

We measure the initial liability and remeasure the liability on a recurring basis using Level 3 inputs as defined under authoritative guidance for fair value measurements and is determined using a discounted cash flow model applied to projected net sales, using probabilities of achieving projected net sales and projected payment dates. Projected net sales are based on our internal projections and extensive analysis of the target market and the sales potential. 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, 2018:



(in thousands)	Fair value at May 31, 2018		Valuation Technique	Unobservable Input	Range
Revenue based payments	$	3,261	Discounted cash flow	Discount rate Probability of payment Projected fiscal year of payment	4% 100% 2019 - 2020

At May 31, 2018, the estimated potential amount of undiscounted future contingent consideration that the Company expects to pay as a result of all completed acquisitions is approximately $3.3 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, 2018

Investments, Debt and Equity Securities [Abstract]

MARKETABLE SECURITIES

As of May 31, 2018, 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	$	—	$	(33	)	$	1,317
	$	1,350	$	—	$	(33	)	$	1,317

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

The amortized cost and fair value of marketable securities as of May 31, 2018, 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, 2018:
Due in one year or less	$	—	$	—
Due after one through five years	—		—
Due after five through twenty years (1)	1,350		1,317
	$	1,350	$	1,317

(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, 2018

Inventory Disclosure [Abstract]

INVENTORIES

As of May 31, 2018 and 2017, inventories consisted of the following:



	May 31, 2018		May 31, 2017
(in thousands)
Raw materials	$	18,678	$	17,563
Work in process	10,808		12,602
Finished goods	19,430		24,341
Total	$	48,916	$	54,506

The Company periodically reviews its inventory 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, 2018 and 2017 was $6.1 million and $7.3 million, respectively. Of the $6.1 million reserve at May 31, 2018, $1.6 million relates to the inventory reserve for Acculis inventory as a result of the recall announced in the fourth quarter of fiscal year 2017 and $0.7 million relates to a specific reserve related to the termination of an agreement with a Japanese distributor in the second quarter of fiscal year 2018. Of the $7.3 million in the prior year, $2.4 million relates to the reserve for Acculis inventory.

Prepaid Expenses and Other

12 Months Ended

May 31, 2018

Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]

PREPAID EXPENSES AND OTHER

As of May 31, 2018 and 2017, prepaid expenses and other consisted of the following:



	May 31, 2018		May 31, 2017
(in thousands)
Software licenses	$	1,043	$	582
License fees	143		118
Trade shows	223		162
Rent	134		121
Other prepaid taxes	254		544
Medical device excise tax receivable	—		1,837
Other	2,505		2,762
Total	$	4,302	$	6,126

Property, Plant and Equipment, Net

12 Months Ended

May 31, 2018

Property, Plant and Equipment [Abstract]

PROPERTY, PLANT AND EQUIPMENT, NET

As of May 31, 2018 and 2017, property, plant and equipment are summarized as follows:



	May 31, 2018			May 31, 2017
(in thousands)
Building and building improvements	$	39,887		$	40,597
Machinery and equipment	22,668			25,434
Computer software and equipment	24,899			25,668
Construction in progress	2,153			1,464
	89,607			93,163
Less accumulated depreciation and amortization	(48,794		)	(49,652		)
	40,813			43,511
Land and land improvements	1,648			1,723
	$	42,461		$	45,234

Depreciation expense for fiscal 2018, 2017 and 2016 was $4.6 million, $6.0 million and $8.2 million, respectively.

Goodwill and Intangible Assets

12 Months Ended

May 31, 2018

Goodwill and Intangible Assets Disclosure [Abstract]

GOODWILL AND INTANGIBLE ASSETS

Even though the Company determined that there was no goodwill impairment as of December 31, 2017, 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, 2018. The Company continued to assess for potential impairment through May 31, 2018 and noted no events that would be considered a triggering event. There were no adjustments to goodwill for the years ended May 31, 2018 and 2017.

As of May 31, 2018 and 2017, intangible assets consisted of the following:



	May 31, 2018
	Gross carrying value		Accumulated amortization			Net carrying value
(in thousands)
Product technologies	$	147,175	$	(68,880	)	$	78,295
Customer relationships	56,428		(23,237		)	33,191
Trademarks	28,400		(11,809		)	16,591
Licenses	5,752		(4,357		)	1,395
Distributor relationships	1,250		(412		)	838
	$	239,005	$	(108,695	)	$	130,310



	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

Amortization expense was $16.6 million, $17.3 million and $18.0 million for fiscal years 2018, 2017 and 2016, respectively.

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



(in thousands)
2019	$	16,555
2020	15,001
2021	13,842
2022	12,958
2023	12,507
2024 and thereafter	59,447
	$	130,310

Income Taxes

12 Months Ended

May 31, 2018

Income Tax Disclosure [Abstract]

INCOME TAXES

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



	2018		2017		2016
(in thousands)
Income (loss) before tax expense:
U.S.	$	6,274	$	8,825	$	(4,444	)
Non-U.S.	1,191		1,022		1,191
	$	7,465	$	9,847	$	(3,253	)

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



	2018			2017		2016
(in thousands)
Current
Federal	$	(148	)	$	—	$	34
State and local	152			141		103
Non U.S.	73			270		217
	77			411		354
Deferred	(8,947		)	4,428		39,983
Income tax (benefit) expense	$	(8,870	)	$	4,839	$	40,337

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



	May 31, 2018			May 31, 2017
(in thousands)
Deferred tax assets
Net operating loss carryforward	$	33,880		$	55,975
Stock-based compensation	2,421			2,653
Federal and state R&D tax credit carryforward	3,644			2,548
Inventories	1,550			2,407
Expenses incurred not currently deductible	1,714			6,522
Accrued liabilities	277			1,289
Gross deferred tax asset	43,486			71,394
Deferred tax liabilities
Excess tax over book depreciation and amortization	34,044			49,158
	34,044			49,158
Valuation Allowance	(26,607		)	(48,348		)
Net deferred tax liability (1)	$	(17,165	)	$	(26,112	)

(1) Net deferred tax liability is inclusive of a non-U.S. $0.08 million deferred tax asset that is included in other assets on the Company's balance sheet for the year ended May 31, 2018.

The net deferred tax liability as of May 31, 2018 and 2017 principally relates to tax amortization of intangibles that have an indefinite reversal period for book purposes, also known as a “naked credit deferred tax liability”, that cannot be considered as a source of income to recover the deferred tax asset.

The Company's Federal net operating loss carryforwards as of May 31, 2018 after considering IRC Section 382 limitations are $157.8 million. The expiration of the Federal net operating loss carryforwards are as follows: $28.8 million between 2018 and 2023 and $129.0 million between 2027 and 2037.

The Company's state net operating loss carryforwards as of May 31, 2018 after considering remaining IRC Section 382 limitations are $19.1 million which expire in various years from 2018 to 2038.

On December 22, 2017, the President of the United States signed into law the Tax Cuts and Jobs Act (“Tax Reform Act”). The legislation significantly changes U.S. tax law by, among other things, lowering corporate income tax rates, implementing a territorial tax system, expanding the tax base and imposing a tax deemed repatriated earnings of foreign subsidiaries. The Tax Reform Act permanently reduces the U.S. corporate federal income tax rate from a maximum of 35% to a flat 21% rate, effective January 1, 2018.

The Company’s estimated fiscal 2018 blended U.S. federal statutory corporate income tax rate of 28.6% was applied in the computation of the income tax provision for the year ended May 31, 2018 and represents the average rate between the pre-enactment U.S. federal statutory corporate tax rate of 35% and the post-enactment U.S. federal statutory corporate tax rate of 21% thereafter.

In December 2017, the Securities and Exchange Commission staff issued Staff Accounting Bulletin No. 118 (SAB 118), which addresses how a company recognizes provisional amounts when a company does not have the necessary information available, prepared or analyzed (including computations) in reasonable detail to complete its accounting for the effect of the changes in the Tax Reform Act. The measurement period ends when a company has obtained, prepared and analyzed the information necessary to finalize its accounting, but cannot extend beyond one year that begins on the date of enactment of December 22, 2017. The Company has elected to apply the measurement period guidance provided in SAB 118. The final impact of the Tax Reform Act may differ from the estimates reported due to, among other things, changes in interpretations and assumptions made by us, additional guidance that may be issued by the U.S. Department of the Treasury and actions that we may take as a result.

The Company has estimated the provision for incomes taxes in accordance with the Tax Reform Act and guidance available as of the date of this filing and as a result recorded a provisional amount of one-time income tax benefit of $9.3 million in the third quarter of fiscal year 2018, the period in which the legislation was enacted. This estimate has not changed as of May 31, 2018.

Due to various uncertainties as described above, the Company has not completed its accounting for certain tax impacts of the Act. A discussion of the most significant impacts of tax law changes under the Act for which the accounting is incomplete is as follows:

The Company is required to record deferred tax assets and liabilities based on the enacted tax rates at which they are expected to reverse in the future. The Company has remeasured its deferred tax positions as of December 31, 2017 at the new enacted tax rate, resulting in a decrease to it net deferred tax assets and a corresponding decrease to its valuation allowance, with no net impact to tax expense. The Company recorded an income tax benefit of approximately $9.3 million due to the revaluation of the naked credit deferred tax liability. The Tax Reform Act changed the NOL carryover rules and created a new limitation on their use. NOLs created in fiscal 2018 and beyond may be carried forwarded indefinitely in any year. As a result, the Company’s naked credit deferred tax liability can now be considered as a source of income to recover indefinite lived NOLs. Consequently, the Company has offset certain of its naked credit deferred tax liability against its deferred tax assets resulting in a reduction in the valuation allowance and a $3.0 million benefit in the year ended May 31, 2018.

The Tax Reform Act imposes a one-time transition tax on the deemed repatriation of post-1986 undistributed foreign subsidiaries’ earnings. Based on the information available as of December 31, 2017, the Company estimated undistributed foreign earnings of approximately $4.9 million. The taxable income arising from this deemed repatriation is expected to result in the utilization of net operating loss carryforwards and other tax credits, offset by changes in the valuation allowance, resulting in no net impact to tax expense.

The Tax Reform Act also creates a new requirement that certain income earned by foreign subsidiaries (“GILTI”), must be included in U.S. gross income. The FASB allows an accounting policy election of either recognizing deferred taxes for temporary differences expected to reverse as GILTI in future years or recognizing such taxes as a current period expense when incurred. The Company has not yet adopted an accounting policy.

The other provisions of the Tax Reform Act are not expected to have a material impact on the Company's financial statements.

The Company regularly assesses its ability to realize its deferred tax assets. Assessing the realization of deferred tax assets requires significant management judgment. In determining whether its deferred tax assets are more likely than not realizable, the Company evaluated all available positive and negative evidence, and weighted the evidence based on its objectivity. Evidence the Company considered included its history of net operating losses, which resulted in the Company recording a full valuation allowance for its deferred tax assets in fiscal 2016 and each year thereafter. The Company was marginally profitable (pretax and adjusted for permanent items) on a cumulative basis for the three years ended May 31, 2018, but substantially all of that profitability was achieved during 2018.

Based on the review of all available evidence, the Company determined that it has not yet attained a sustained level of profitability and the objectively verifiable negative evidence outweighed the positive evidence and therefore the Company has provided a valuation allowance for the full amount, with the exception of the naked credit deferred tax liability, of its net deferred tax asset as of May 31, 2018. The decrease in the valuation allowance during fiscal 2018 was principally due to the impact of tax reform as discussed above. The Company will continue to assess the level of the valuation allowance required. If sufficient positive evidence exists in future periods to support a release of some or all of the valuation allowance, such a release would likely have a material impact on the Company’s results of operations.

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:



	Year ended May 31,
	2018			2017			2016
(in thousands)
Income tax (benefit) expense at statutory tax rate of 28.6%, 35.0% and 35.0%, respectively	$	2,136		$	3,447		$	(1,139	)
Effect of graduated tax rates	—			(98		)	33
State income taxes, net of Federal tax benefit	120			(22		)	(215		)
Impact of Non-U.S. operations	(288		)	403			(162		)
Research and development tax credit	(951		)	(403		)	(499		)
Impact of tax reform	10,912			—			—
Meals and entertainment	242			266			329
Non-deductible interest on contingent payments	—			174			262
Non-taxable gain on revaluation of contingent consideration liability	—			(5,576		)	(170		)
Change in valuation allowance	(21,741		)	6,139			40,685
Effect of elimination of stock compensation APIC pool	—			1,380			739
IPR&D intangible write-off	—			(1,224		)	—
Other	700			353			474
Income tax (benefit) expense	$	(8,870	)	$	4,839		$	40,337

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



	Year ended May 31,
	2018			2017		2016
(in thousands)
Unrecognized tax benefits balance at June 1	$	899		$	899	$	—
Increase in gross amounts of tax positions related to prior years	—			—		899
Decrease in gross amounts of tax positions related to prior years due to U.S. tax reform	(287		)	—		—
Decrease due to lapse in statute of limitations	(148		)	—		—
Unrecognized tax benefits balance at May 31	$	464		$	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 $0.5 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, 2018 and May 31, 2017.

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 2015 through 2018 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 amounted to $4.9 million and $5.3 million at May 31, 2018 and 2017, respectively. These earnings are considered indefinitely reinvested. Beginning in 2018, except for GILTI, the Company will no longer record United States federal income tax on its share of the income of its foreign subsidiaries, nor will it record a benefit for foreign tax credits related to that income. Upon distribution of these earnings in the form of dividends or otherwise, the Company would be subject to withholding taxes payable, where applicable, to foreign countries, but would have no further federal income tax liability.

Accrued Liabilities

12 Months Ended

May 31, 2018

Payables and Accruals [Abstract]

ACCRUED LIABILITIES

As of May 31, 2018 and 2017, accrued liabilities consist of the following:



	May 31, 2018		May 31, 2017
(in thousands)
Payroll and related expenses	$	10,235	$	11,383
Royalties	1,537		2,885
Accrued severance	1,940		2,075
Sales and franchise taxes	683		856
Outside services	2,396		1,622
Litigation matters (Note 15)	12,500		12,500
Acculis recall liability	—		2,563
Other	5,135		4,920
Total	$	34,426	$	38,804

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 and recorded a liability of $2.6 million. In the third quarter of fiscal year 2018, the Company completed the replacement of Acculis probes that were returned for Solero probes.

Long-Term Debt

12 Months Ended

May 31, 2018

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. As of May 31, 2018 and 2017 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, 2018 was 3.41%.

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 and in Amendment One, dated May 24, 2018 and included as an exhibit to the fiscal 2018 Form 10-K. This amendment increased the amount of U.S. cash that can be utilized to calculate net debt from $10.0 million to $20.0 million.

The Company was in compliance with both covenants as of May 31, 2018.

The Company's maturities of principal obligations under the credit agreement are as follows, as of May 31, 2018:



(in thousands)
2019	$	5,000
2020	7,500
2021	11,250
2022	68,750
Total term loan	92,500
Revolving facility	—
Total debt	92,500
Less: Unamortized debt issuance costs	(879		)
Total	91,621
Less: Current portion of long-term debt	(5,000		)
Total long-term debt, net of current portion	$	86,621

Retirement Plans	12 Months Ended
Retirement Plans	May 31, 2018
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 $3.9 million, $4.2 million and $3.7 million in 2018, 2017 and 2016, respectively. There are also various immaterial foreign retirement plans.

Stockholders' Equity

12 Months Ended

May 31, 2018

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, 2018, there remained approximately 1.8 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, 2018:



	Shares		Weighted- average exercise price		Weighted average remaining contractual life	Aggregate intrinsic value (in thousands)
Outstanding at beginning of year - June 1, 2017	1,667,443		$	15.01
Granted	518,498		$	16.78
Exercised	(271,344	)	$	14.83
Forfeited	(204,184	)	$	16.24
Expired	(14,000	)	$	15.75
Outstanding at end of year - May 31, 2018	1,696,413		$	15.42	5.58	$	9,520
Options exercisable at year-end	652,543		$	14.41	3.48	$	4,321
Options expected to vest in future periods	1,043,870		$	16.05	6.90	$	5,199

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. Grants to directors vest 33.33% per year over three years. Stock options granted prior to May 1, 2007 and after June 1, 2017 expire on the tenth anniversary of the grant date. Stock options granted between May 1, 2007 through May 31, 2017 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, 2018, 2017 and 2016 was $4.95, $4.70, and $4.16, respectively. The following assumptions were used in arriving at the fair value of options granted during 2018, 2017 and 2016, respectively: risk-free interest rates of 2.08%, 1.30% and 1.48%; expected volatility of 30%, 31%, and 31%; and expected lives of 4.72 years, 4.80 years, and 4.81 years. The Company does not declare dividends therefore a dividend yield of zero was used for the years ended May 31, 2018, 2017 and 2016. 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, 2018, 2017 and 2016 was $0.7 million, $2.8 million, and $0.1 million, respectively. As of May 31, 2018, there was $3.9 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 2018, 2017 and 2016 was $2.0 million, $9.9 million and $1.3 million, respectively. The tax benefit realized from stock options exercised during the year ended May 31, 2016 was $0.1 million. Due to the valuation allowance there was no tax benefit realized from stock option exercises during the years ended May 31, 2018 and 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 four equal annual installments beginning on the first anniversary of the grant date. Restricted stock unit awards granted to directors vest over one year. 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, 2018:



	Restricted Stock Units		Weighted Average Grant-Date Fair Value
Non-vested at beginning of year, June 1, 2017	439,297		$	15.55
Granted	299,392		$	16.60
Vested	(158,756	)	$	16.83
Canceled	(105,431	)	$	18.25
Non-vested at end of year, May 31, 2018	474,502		$	16.23

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, 2018, 2017 and 2016 was $16.60, $16.54 and $15.21, 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, 2018, 2017 and 2016 was $2.7 million, $2.9 million, and $2.5 million, respectively. As of May 31, 2018, there was $5.1 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 is determined by the achievement of relative total shareholder return ("TSR"). 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, 2018:



	Performance Unit Awards		Weighted Average Grant-Date Fair Value
Non-vested at beginning of year, June 1, 2017	361,164		$	18.54
Granted	135,135		$	23.83
Vested	—		$	—
Canceled	(44,443	)	$	22.76
Non-vested at end of year, May 31, 2018	451,856		$	19.75

During fiscal years 2018, 2017 and 2016, 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, 2018, 2017 and 2016, the weighted average grant date fair market value for new grants was $23.83, $22.61 and $18.07, respectively. Compensation cost is recognized over the performance period which is typically three years. As of May 31, 2018, 0.5 million performance share units with a weighted average remaining contractual term of 2 years and $3.9 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:



	Year ended May 31,
(in thousands)	2018		2017			2016
Cost of sales	$	119	$	299		$	172
Research and development	554		314			349
Sales and marketing	1,778		1,762			1,489
General and administrative	5,461		4,026			2,291
Acquisition, restructuring and other items, net	—		(218		)	(1,061		)
	$	7,912	$	6,183		$	3,240

The income tax benefit on the compensation expense recognized for all share-based compensation arrangements was $1.8 million, $2.2 million and $1.0 million for the years ended May 31, 2018, 2017 and 2016, respectively. The income tax benefit for 2018, 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 were 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, 2018, 2017 and 2016, 89,943, 129,185 and 137,957 shares, respectively, were issued at an average price of $14.03, $11.00 and $10.67, respectively, under the Stock Purchase Plan. As of May 31, 2018, 1.2 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, 2018, $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.

Earnings Per Share

12 Months Ended

May 31, 2018

Earnings Per Share [Abstract]

EARNINGS PER SHARE

Basic earnings per share are based on the weighted average number of common shares outstanding. In addition, diluted earnings per share include the dilutive effect of potential common stock consisting of stock options, restricted stock units and performance stock units, provided that the inclusion of such securities is not anti-dilutive. In periods with a net loss, stock options and restricted stock units are not included in the computation of basic loss per share as the impact would be anti-dilutive.

The following table reconciles basic to diluted weighted average shares outstanding for the years ended May 31, 2018, 2017 and 2016:



	Year ended May 31,
	2018	2017	2016
Basic	37,074,797	36,616,859	36,161,383
Effect of dilutive securities	464,603	342,391	—
Diluted	37,539,400	36,959,250	36,161,383

Securities excluded as their inclusion would be anti-dilutive	1,077,256	1,058,790	3,277,037

Commitments and Contingencies

12 Months Ended

May 31, 2018

Commitments and Contingencies Disclosure [Abstract]

COMMITMENTS AND CONTINGENCIES

Leases

The Company is committed under non-cancelable operating leases for facilities and equipment. During fiscal 2018, 2017 and 2016, aggregate rental costs under all operating leases were approximately $2.8 million, $2.5 million and $2.5 million, respectively. Future annual payments under non-cancelable operating leases in the aggregate, of which one includes an escalation clause, with initial remaining terms of more than one year at May 31, 2018, are summarized as follows (in thousands):



(in thousands)
2019	$	2,234
2020	1,829
2021	993
2022	884
2023 and thereafter	1,668
	$	7,608

Other Commitments and Contingencies

The following table summarizes the Company's other future commitments and contingencies as of May 31, 2018



(in thousands)	Total		2019		2020		2021		2022		2023 and thereafter
Purchase obligations (1)	$	56,201	$	11,751	$	14,243	$	15,485	$	9,189	$	5,533
Royalties	45,000		3,000		3,500		3,500		3,500		31,500
Other	667		167		167		167		166		—
	$	101,868	$	14,918	$	17,910	$	19,152	$	12,855	$	37,033


(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’s Complaint sought unspecified damages and other relief. We filed petitions for reexamination in the U.S. Patent and Trademark Office (“USPTO”) seeking to invalidate all three patents asserted by Bard in the litigation. Our petitions were granted and 40 of Bard's 41 patent 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 USPTO Board of Appeals and Interferences for all three reexaminations. The Patent Office issued decisions in all three appeals. In one (issued on March 11, 2016 for U.S. 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. Thereafter, Bard 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). The PTO denied all three Rehearing Requests - - on February 1, 2017 for the ‘302 reexam; on February 17, 2017 for the ‘022 reexam; and on February 21, 2017 for the ‘615 reexam, but modified its characterization of one prior art reference for the ‘302 and ‘022 decisions. Bard filed a Notice of Appeal to the Federal Circuit Court of Appeals in all three reexams and the Company filed Cross-Appeals for the ‘302 and the ‘615 reexams. The parties have completed the process of filing the various appellate briefs. MedComp also filed an Amicus Brief in support of the Company on November 22, 2017. A date for the oral hearing has not yet been set. The Utah Action has been stayed pending final resolution of the USPTO 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. (“Bard”) and Bard Peripheral Vascular, Inc. (“BPV”) 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's complaint seeks 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, the Company 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. A Markman hearing was held on March 10, 2017 and the Court issued its Claim Construction Order on May 19, 2017. On May 19, 2017, Bard served its Final Infringement Contentions and on June 2, 2017, the Company served its Final Invalidity Contentions.

On October 20, 2017, the scheduling order for the case was amended to, among other things, set a trial date commencing July 23, 2018. The parties completed Expert Discovery in January 2018. The parties completed briefing on their respective case dispositive motions on April 27, 2018. On June 26, 2018, the Court denied all case dispositive motions, ruling that issues of material fact remained in dispute. On July 9, 2018, the Court continued the trial to a later date to be determined by the Court and the parties. 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. Bard moved to dismiss on September 8, 2017 and the motion has been submitted to the court. The court has adjourned the initial conference in the case pending its resolution of the motion to dismiss.

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. This amount was still accrued for at May 31, 2018 and was paid in the first quarter of fiscal year 2019.

Segments and Geographic Information

12 Months Ended

May 31, 2018

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):



	Year ended May 31,
(in thousands)	2018		2017		2016
Net sales by Product Category
Peripheral Vascular	$	202,334	$	208,602	$	205,620
Vascular Access	92,760		96,481		99,375
Oncology/Surgery	49,191		44,560		48,895
Total	$	344,285	$	349,643	$	353,890

Geographic information

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



	Year ended May 31,
(in thousands)	2018		2017		2016
Net sales by Geography
United States	$	273,327	$	282,168	$	285,824
International	70,958		67,475		68,066
Total	$	344,285	$	349,643	$	353,890

For fiscal years 2018, 2017 and 2016, International sales as a percentage of total net sales were 21%, 19% and 19%, 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, 2018

Restructuring and Related Activities [Abstract]

ACQUISITION, RESTRUCTURING AND OTHER ITEMS, NET

For the years ended May 31, 2018, 2017 and 2016 acquisition, restructuring and other items, net consisted of:



	Year ended May 31,
(in thousands)	2018		2017		2016
Legal	$	10,067	$	19,480	$	7,487
Intangible and other asset impairment	—		5,604		352
Restructuring	4,674		1,348		1,462
Other	691		1,078		3,290
Total	$	15,432	$	27,510	$	12,591

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. The remaining legal expenses relate to litigation that is outside of the normal course of business.

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 were completed in the fourth quarter of fiscal year 2018 with immaterial validation costs to be incurred in the first quarter of fiscal year 2019.

The Company recorded restructuring charges related to the plan during the year ended May 31, 2018 and 2017 of $4.7 million and $1.3 million, respectively. Total restructuring charges recorded as part of the plan were $6.0 million. 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 years ended May 31, 2018 and 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
Charges	1,440			2,892			68			200		74			4,674
Non-cash adjustments	—			(276		)	—			—		—			(276		)
Cash payments	(1,453		)	(2,706		)	(56		)	—		(74		)	(4,289		)
Balance at May 31, 2018	$	838		$	21		$	12		$	200	$	—		$	1,071

The Company’s restructuring liability of $1.1 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)

12 Months Ended

May 31, 2018

Equity [Abstract]

ACCUMULATED OTHER COMPREHESIVE INCOME (LOSS)

Changes in each component of accumulated other comprehensive income (loss), net of tax, are as follows for fiscal 2018 and 2017:



(in thousands)	Foreign currency translation gain (loss)			Unrealized gain (loss) on marketable securities			Total
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	)
Other comprehensive income before reclassifications, net of tax	270			102			372
Amounts reclassified from accumulated other comprehensive income	—			—			—
Net other comprehensive income	$	270		$	102		$	372
Balance at May 31, 2018	$	(1,035	)	$	83		$	(952	)

Quarterly Information (unaudited)

12 Months Ended

May 31, 2018

Quarterly Financial Information Disclosure [Abstract]

QUARTERLY INFORMATION (unaudited)

Quarterly results of operations during the fiscal years ended May 31, 2018 and 2017 are as follows:



	2018
	First quarter			Second quarter		Third quarter		Fourth quarter
(in thousands, except per share data)
Net sales	$	85,411		$	86,706	$	83,851	$	88,317
Gross profit	41,229			42,731		45,448		47,467
Net income (loss) (1)	(35		)	249		14,019		2,102
Earnings (loss) per common share
Basic	0.00			0.01		0.38		0.06
Diluted	0.00			0.01		0.37		0.06



	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) (2)	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 during the third quarter of fiscal 2018 is a $9.3 million discrete tax benefit as a result of the Tax Reform Act and the revaluation of the Company's deferred tax assets, liabilities and valuation allowance to reflect the lower U.S. federal statutory rate (see Note 9).

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

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, 2018

SEC Schedule, 12-09, Valuation and Qualifying Accounts [Abstract]

VALUATION AND QUALIFYING ACCOUNTS



	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, 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
Year Ended May 31, 2018
Allowance for deferred tax asset	$	48,348	$	—		$	(21,741	)	$	26,607
Allowance for sales returns and doubtful accounts	$	2,945	$	608		$	(1,087	)	$	2,466

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

12 Months Ended

May 31, 2018

Accounting Policies [Abstract]

Basis of Presentation and Description of Business

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

Cash and Cash Equivalents

Marketable Securities

Fair Value Instruments

Accounts Receivable

Inventories

Property, Plant and Equipment



		Estimated useful lives
Building and building improvements		39 years
Machinery and equipment		5 to 8 years
Computer software and equipment		3 to 5 years

Goodwill and Intangible Assets

Contingent Consideration

Revenue Recognition

Research and Development

Income Taxes

Warranty Costs

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

Stock Based Compensation

Foreign Currency Translation

Derivative Financial Instruments

Contingencies

Recently Issued Accounting Pronouncements

The following table provides a description of recent accounting pronouncements that may have a material effect on the Company's consolidated financial statements:



Recently Issued Accounting Pronouncements - Adopted
Standard	Description	Date Adopted	Effect on the Consolidated Financial Statements
ASU 2016-09, Compensation - Stock Based Compensation (Topic 718: Improvements to Employee Share-Based Payment Accounting)	This ASU 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.	June 1, 2017	The Company now recognizes unrealized excess tax benefits and will classify such benefits as an operating activity in the statement of cash flows on a prospective basis. Due to the full valuation allowance on our federal and state income taxes, the adoption of ASU 2016-09 did not impact our accounting for income taxes.
			The Company elected the accounting policy change to account for forfeitures as they occur. This was adopted using the modified retrospective transition method by means of a cumulative-effect adjustment to equity as of June 1, 2017. The adoption of ASU 2016-09 did not materially impact the Company's consolidated statements of income, consolidated balance sheet, equity or cash flows.
ASU 2017-04, Intangibles - Goodwill and Other (Topic 350)	This ASU simplifies the subsequent measurement of goodwill by eliminating steps from the goodwill impairment test.	June 1, 2017	This adoption did not have an impact on the Company's financial statements.
ASC Update No. 2015-11, Inventory (Topic 330): Simplifying the Measurement of Inventory. Update No. 2015-11	This ASU 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.	June 1, 2017	This adoption did not have an impact on the Company's financial statements.



Recently Issued Accounting Pronouncements - Not Yet Applicable or Adopted
Standard	Description	Effective Date	Effect on the Consolidated Financial Statements
ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606, ASU 2014-09)	Under Topic 606, an entity is required to recognize revenue upon transfer of promised goods or services to customers in an amount that reflects the expected consideration to be received in exchange for those goods or services. Topic 606 defines a five-step process in order to achieve this core principle, which may require the use of judgment and estimates, and also requires expanded qualitative and quantitative disclosures relating to the nature, amount, timing and uncertainty of revenue and cash flows arising from contracts with customers, including significant judgments and estimates used. The new standard also defines accounting for certain costs related to origination and fulfillment of contracts with customers, including whether such costs should be capitalized.	June 1, 2018	The Company established an implementation team which included third-party specialists to assist in the evaluation and implementation of the new standard. The Company’s assessment has included performing analysis for each revenue stream identified, assessing the potential differences in recognition and measurement that may result from adopting this standard and assessing whether the Company meets certain practical expedients. Based on the results of the assessment, the adoption of this standard will not have a material impact on the timing or amount of revenue recognized upon adoption and there is no cumulative prior period adjustment to be recorded to the opening balance of retained earnings upon adoption. The Company will adopt the standard using the modified retrospective method. The Company is implementing changes to accounting policies, business processes and internal controls to support the new standard as necessary. Upon adoption of Topic 606, as the disclosure requirements under the new guidance have been significantly expanded in comparison to the disclosure requirements under the current guidance, we will provide additional disclosures in the notes to the consolidated financial statements, specifically related to performance obligations, the judgments made in revenue recognition determinations, costs to obtain or fulfill contracts and contract balances.
ASU No. 2016-15, Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments (ASU 2016-15)	This ASU identifies how certain cash receipts and cash payments are presented and classified in the Statement of Cash Flows under Topic 230.	June 1, 2018	This adoption is not expected to have a material impact on the Company's financial statements.
ASU 2016-02, Leases (Topic 842)	This ASU 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 of 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.	June 1, 2019	The Company is currently in the process of evaluating the impact of this ASU on its consolidated financial statements.

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

12 Months Ended

May 31, 2018

Accounting Policies [Abstract]

Property, plant and equipment

Refer below for useful lives by category:



		Estimated useful lives
Building and building improvements		39 years
Machinery and equipment		5 to 8 years
Computer software and equipment		3 to 5 years

As of May 31, 2018 and 2017, property, plant and equipment are summarized as follows:



	May 31, 2018			May 31, 2017
(in thousands)
Building and building improvements	$	39,887		$	40,597
Machinery and equipment	22,668			25,434
Computer software and equipment	24,899			25,668
Construction in progress	2,153			1,464
	89,607			93,163
Less accumulated depreciation and amortization	(48,794		)	(49,652		)
	40,813			43,511
Land and land improvements	1,648			1,723
	$	42,461		$	45,234

Recent accounting pronouncements

The following table provides a description of recent accounting pronouncements that may have a material effect on the Company's consolidated financial statements:



Recently Issued Accounting Pronouncements - Adopted
Standard	Description	Date Adopted	Effect on the Consolidated Financial Statements
ASU 2016-09, Compensation - Stock Based Compensation (Topic 718: Improvements to Employee Share-Based Payment Accounting)	This ASU 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.	June 1, 2017	The Company now recognizes unrealized excess tax benefits and will classify such benefits as an operating activity in the statement of cash flows on a prospective basis. Due to the full valuation allowance on our federal and state income taxes, the adoption of ASU 2016-09 did not impact our accounting for income taxes.
			The Company elected the accounting policy change to account for forfeitures as they occur. This was adopted using the modified retrospective transition method by means of a cumulative-effect adjustment to equity as of June 1, 2017. The adoption of ASU 2016-09 did not materially impact the Company's consolidated statements of income, consolidated balance sheet, equity or cash flows.
ASU 2017-04, Intangibles - Goodwill and Other (Topic 350)	This ASU simplifies the subsequent measurement of goodwill by eliminating steps from the goodwill impairment test.	June 1, 2017	This adoption did not have an impact on the Company's financial statements.
ASC Update No. 2015-11, Inventory (Topic 330): Simplifying the Measurement of Inventory. Update No. 2015-11	This ASU 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.	June 1, 2017	This adoption did not have an impact on the Company's financial statements.



Recently Issued Accounting Pronouncements - Not Yet Applicable or Adopted
Standard	Description	Effective Date	Effect on the Consolidated Financial Statements
ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606, ASU 2014-09)	Under Topic 606, an entity is required to recognize revenue upon transfer of promised goods or services to customers in an amount that reflects the expected consideration to be received in exchange for those goods or services. Topic 606 defines a five-step process in order to achieve this core principle, which may require the use of judgment and estimates, and also requires expanded qualitative and quantitative disclosures relating to the nature, amount, timing and uncertainty of revenue and cash flows arising from contracts with customers, including significant judgments and estimates used. The new standard also defines accounting for certain costs related to origination and fulfillment of contracts with customers, including whether such costs should be capitalized.	June 1, 2018	The Company established an implementation team which included third-party specialists to assist in the evaluation and implementation of the new standard. The Company’s assessment has included performing analysis for each revenue stream identified, assessing the potential differences in recognition and measurement that may result from adopting this standard and assessing whether the Company meets certain practical expedients. Based on the results of the assessment, the adoption of this standard will not have a material impact on the timing or amount of revenue recognized upon adoption and there is no cumulative prior period adjustment to be recorded to the opening balance of retained earnings upon adoption. The Company will adopt the standard using the modified retrospective method. The Company is implementing changes to accounting policies, business processes and internal controls to support the new standard as necessary. Upon adoption of Topic 606, as the disclosure requirements under the new guidance have been significantly expanded in comparison to the disclosure requirements under the current guidance, we will provide additional disclosures in the notes to the consolidated financial statements, specifically related to performance obligations, the judgments made in revenue recognition determinations, costs to obtain or fulfill contracts and contract balances.
ASU No. 2016-15, Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments (ASU 2016-15)	This ASU identifies how certain cash receipts and cash payments are presented and classified in the Statement of Cash Flows under Topic 230.	June 1, 2018	This adoption is not expected to have a material impact on the Company's financial statements.
ASU 2016-02, Leases (Topic 842)	This ASU 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 of 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.	June 1, 2019	The Company is currently in the process of evaluating the impact of this ASU on its consolidated financial statements.

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

12 Months Ended

May 31, 2018

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, 2018
Financial Assets
Short-term investments*	$	2,100	$	—	$	—	$	2,100
Marketable securities	—		—		1,317		1,317
Total Financial Assets	$	2,100	$	—	$	1,317	$	3,417
Financial Liabilities
Contingent liability for acquisition earn outs	$	—	$	—	$	3,261	$	3,261
Total Financial Liabilities	$	—	$	—	$	3,261	$	3,261

*included in cash and cash equivalents.



	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, 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, 2018 (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, 2017	$	1,215	$	12,761
Change in fair value of contingent consideration, net (1)	—		250
Fair market value adjustments	102		—
Contingent consideration payments	—		(9,750		)
Balance at May 31, 2018	$	1,317	$	3,261

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 (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

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, 2018:



(in thousands)	Fair value at May 31, 2018		Valuation Technique	Unobservable Input	Range
Revenue based payments	$	3,261	Discounted cash flow	Discount rate Probability of payment Projected fiscal year of payment	4% 100% 2019 - 2020

Marketable Securities (Tables)

12 Months Ended

May 31, 2018

Investments, Debt and Equity Securities [Abstract]

Marketable securities

As of May 31, 2018, 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	$	—	$	(33	)	$	1,317
	$	1,350	$	—	$	(33	)	$	1,317

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

Amortized cost and fair value of marketable securities by contractual maturity



	Amortized Cost		Fair Value
(in thousands)
As of May 31, 2018:
Due in one year or less	$	—	$	—
Due after one through five years	—		—
Due after five through twenty years (1)	1,350		1,317
	$	1,350	$	1,317

(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, 2018

Inventory Disclosure [Abstract]

Inventories

As of May 31, 2018 and 2017, inventories consisted of the following:



	May 31, 2018		May 31, 2017
(in thousands)
Raw materials	$	18,678	$	17,563
Work in process	10,808		12,602
Finished goods	19,430		24,341
Total	$	48,916	$	54,506

Prepaid Expenses and Other (Tables)

12 Months Ended

May 31, 2018

Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]

Prepaid expenses and other

As of May 31, 2018 and 2017, prepaid expenses and other consisted of the following:



	May 31, 2018		May 31, 2017
(in thousands)
Software licenses	$	1,043	$	582
License fees	143		118
Trade shows	223		162
Rent	134		121
Other prepaid taxes	254		544
Medical device excise tax receivable	—		1,837
Other	2,505		2,762
Total	$	4,302	$	6,126

Property, Plant and Equipment, Net (Tables)

12 Months Ended

May 31, 2018

Property, Plant and Equipment [Abstract]

Property, plant and equipment

Refer below for useful lives by category:



		Estimated useful lives
Building and building improvements		39 years
Machinery and equipment		5 to 8 years
Computer software and equipment		3 to 5 years

As of May 31, 2018 and 2017, property, plant and equipment are summarized as follows:



	May 31, 2018			May 31, 2017
(in thousands)
Building and building improvements	$	39,887		$	40,597
Machinery and equipment	22,668			25,434
Computer software and equipment	24,899			25,668
Construction in progress	2,153			1,464
	89,607			93,163
Less accumulated depreciation and amortization	(48,794		)	(49,652		)
	40,813			43,511
Land and land improvements	1,648			1,723
	$	42,461		$	45,234

Goodwill and Intangible Assets (Tables)

12 Months Ended

May 31, 2018

Goodwill and Intangible Assets Disclosure [Abstract]

Intangible assets

As of May 31, 2018 and 2017, intangible assets consisted of the following:



	May 31, 2018
	Gross carrying value		Accumulated amortization			Net carrying value
(in thousands)
Product technologies	$	147,175	$	(68,880	)	$	78,295
Customer relationships	56,428		(23,237		)	33,191
Trademarks	28,400		(11,809		)	16,591
Licenses	5,752		(4,357		)	1,395
Distributor relationships	1,250		(412		)	838
	$	239,005	$	(108,695	)	$	130,310



	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

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)
2019	$	16,555
2020	15,001
2021	13,842
2022	12,958
2023	12,507
2024 and thereafter	59,447
	$	130,310

Income Taxes (Tables)

12 Months Ended

May 31, 2018

Income Tax Disclosure [Abstract]

Components of income (loss) before income tax provision

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



	2018		2017		2016
(in thousands)
Income (loss) before tax expense:
U.S.	$	6,274	$	8,825	$	(4,444	)
Non-U.S.	1,191		1,022		1,191
	$	7,465	$	9,847	$	(3,253	)

Summary of Income tax (benefit) provision analyzed by category

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



	2018			2017		2016
(in thousands)
Current
Federal	$	(148	)	$	—	$	34
State and local	152			141		103
Non U.S.	73			270		217
	77			411		354
Deferred	(8,947		)	4,428		39,983
Income tax (benefit) expense	$	(8,870	)	$	4,839	$	40,337

Summary of deferred tax asset and liabilities

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



	May 31, 2018			May 31, 2017
(in thousands)
Deferred tax assets
Net operating loss carryforward	$	33,880		$	55,975
Stock-based compensation	2,421			2,653
Federal and state R&D tax credit carryforward	3,644			2,548
Inventories	1,550			2,407
Expenses incurred not currently deductible	1,714			6,522
Accrued liabilities	277			1,289
Gross deferred tax asset	43,486			71,394
Deferred tax liabilities
Excess tax over book depreciation and amortization	34,044			49,158
	34,044			49,158
Valuation Allowance	(26,607		)	(48,348		)
Net deferred tax liability (1)	$	(17,165	)	$	(26,112	)

(1) Net deferred tax liability is inclusive of a non-U.S. $0.08 million deferred tax asset that is included in other assets on the Company's balance sheet for the year ended May 31, 2018.

Summary of Income tax rate reconciliation



	Year ended May 31,
	2018			2017			2016
(in thousands)
Income tax (benefit) expense at statutory tax rate of 28.6%, 35.0% and 35.0%, respectively	$	2,136		$	3,447		$	(1,139	)
Effect of graduated tax rates	—			(98		)	33
State income taxes, net of Federal tax benefit	120			(22		)	(215		)
Impact of Non-U.S. operations	(288		)	403			(162		)
Research and development tax credit	(951		)	(403		)	(499		)
Impact of tax reform	10,912			—			—
Meals and entertainment	242			266			329
Non-deductible interest on contingent payments	—			174			262
Non-taxable gain on revaluation of contingent consideration liability	—			(5,576		)	(170		)
Change in valuation allowance	(21,741		)	6,139			40,685
Effect of elimination of stock compensation APIC pool	—			1,380			739
IPR&D intangible write-off	—			(1,224		)	—
Other	700			353			474
Income tax (benefit) expense	$	(8,870	)	$	4,839		$	40,337

Summary of unrecognized tax benefits reconciliation

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



	Year ended May 31,
	2018			2017		2016
(in thousands)
Unrecognized tax benefits balance at June 1	$	899		$	899	$	—
Increase in gross amounts of tax positions related to prior years	—			—		899
Decrease in gross amounts of tax positions related to prior years due to U.S. tax reform	(287		)	—		—
Decrease due to lapse in statute of limitations	(148		)	—		—
Unrecognized tax benefits balance at May 31	$	464		$	899	$	899

Accrued Liabilities (Tables)

12 Months Ended

May 31, 2018

Payables and Accruals [Abstract]

Accrued liabilities

As of May 31, 2018 and 2017, accrued liabilities consist of the following:



	May 31, 2018		May 31, 2017
(in thousands)
Payroll and related expenses	$	10,235	$	11,383
Royalties	1,537		2,885
Accrued severance	1,940		2,075
Sales and franchise taxes	683		856
Outside services	2,396		1,622
Litigation matters (Note 15)	12,500		12,500
Acculis recall liability	—		2,563
Other	5,135		4,920
Total	$	34,426	$	38,804

Long-Term Debt (Tables)

12 Months Ended

May 31, 2018

Debt Disclosure [Abstract]

Future minimum principal payments on long-term debt

The Company's maturities of principal obligations under the credit agreement are as follows, as of May 31, 2018:



(in thousands)
2019	$	5,000
2020	7,500
2021	11,250
2022	68,750
Total term loan	92,500
Revolving facility	—
Total debt	92,500
Less: Unamortized debt issuance costs	(879		)
Total	91,621
Less: Current portion of long-term debt	(5,000		)
Total long-term debt, net of current portion	$	86,621

Stockholders' Equity (Tables)

12 Months Ended

May 31, 2018

Equity [Abstract]

Schedule summarizes stock option activity

The following table summarizes information about stock option activity for the fiscal year ended May 31, 2018:



	Shares		Weighted- average exercise price		Weighted average remaining contractual life	Aggregate intrinsic value (in thousands)
Outstanding at beginning of year - June 1, 2017	1,667,443		$	15.01
Granted	518,498		$	16.78
Exercised	(271,344	)	$	14.83
Forfeited	(204,184	)	$	16.24
Expired	(14,000	)	$	15.75
Outstanding at end of year - May 31, 2018	1,696,413		$	15.42	5.58	$	9,520
Options exercisable at year-end	652,543		$	14.41	3.48	$	4,321
Options expected to vest in future periods	1,043,870		$	16.05	6.90	$	5,199

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, 2018:



	Performance Unit Awards		Weighted Average Grant-Date Fair Value
Non-vested at beginning of year, June 1, 2017	361,164		$	18.54
Granted	135,135		$	23.83
Vested	—		$	—
Canceled	(44,443	)	$	22.76
Non-vested at end of year, May 31, 2018	451,856		$	19.75

The following table summarizes information about restricted stock unit activity for the year ended May 31, 2018:



	Restricted Stock Units		Weighted Average Grant-Date Fair Value
Non-vested at beginning of year, June 1, 2017	439,297		$	15.55
Granted	299,392		$	16.60
Vested	(158,756	)	$	16.83
Canceled	(105,431	)	$	18.25
Non-vested at end of year, May 31, 2018	474,502		$	16.23

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:



	Year ended May 31,
(in thousands)	2018		2017			2016
Cost of sales	$	119	$	299		$	172
Research and development	554		314			349
Sales and marketing	1,778		1,762			1,489
General and administrative	5,461		4,026			2,291
Acquisition, restructuring and other items, net	—		(218		)	(1,061		)
	$	7,912	$	6,183		$	3,240

Earnings Per Share (Tables)

12 Months Ended

May 31, 2018

Earnings Per Share [Abstract]

Schedule of Weighted Average Number of Shares

The following table reconciles basic to diluted weighted average shares outstanding for the years ended May 31, 2018, 2017 and 2016:



	Year ended May 31,
	2018	2017	2016
Basic	37,074,797	36,616,859	36,161,383
Effect of dilutive securities	464,603	342,391	—
Diluted	37,539,400	36,959,250	36,161,383

Securities excluded as their inclusion would be anti-dilutive	1,077,256	1,058,790	3,277,037

Commitments And Contingencies (Tables)

12 Months Ended

May 31, 2018

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, 2018, are summarized as follows (in thousands):



(in thousands)
2019	$	2,234
2020	1,829
2021	993
2022	884
2023 and thereafter	1,668
	$	7,608

Other commitments and contingencies

The following table summarizes the Company's other future commitments and contingencies as of May 31, 2018



(in thousands)	Total		2019		2020		2021		2022		2023 and thereafter
Purchase obligations (1)	$	56,201	$	11,751	$	14,243	$	15,485	$	9,189	$	5,533
Royalties	45,000		3,000		3,500		3,500		3,500		31,500
Other	667		167		167		167		166		—
	$	101,868	$	14,918	$	17,910	$	19,152	$	12,855	$	37,033


(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, 2018

Segment Reporting [Abstract]

Summary of total net sales by product category

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



	Year ended May 31,
(in thousands)	2018		2017		2016
Net sales by Product Category
Peripheral Vascular	$	202,334	$	208,602	$	205,620
Vascular Access	92,760		96,481		99,375
Oncology/Surgery	49,191		44,560		48,895
Total	$	344,285	$	349,643	$	353,890

Summary of net sales for geographic areas

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



	Year ended May 31,
(in thousands)	2018		2017		2016
Net sales by Geography
United States	$	273,327	$	282,168	$	285,824
International	70,958		67,475		68,066
Total	$	344,285	$	349,643	$	353,890

Acquisition, Restructuring and Other Items, net (Tables)

12 Months Ended

May 31, 2018

Restructuring and Related Activities [Abstract]

Acquisition, Restructuring and Other Items, net

For the years ended May 31, 2018, 2017 and 2016 acquisition, restructuring and other items, net consisted of:



	Year ended May 31,
(in thousands)	2018		2017		2016
Legal	$	10,067	$	19,480	$	7,487
Intangible and other asset impairment	—		5,604		352
Restructuring	4,674		1,348		1,462
Other	691		1,078		3,290
Total	$	15,432	$	27,510	$	12,591

The following table presents a rollforward of the restructuring reserve for the years ended May 31, 2018 and 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
Charges	1,440			2,892			68			200		74			4,674
Non-cash adjustments	—			(276		)	—			—		—			(276		)
Cash payments	(1,453		)	(2,706		)	(56		)	—		(74		)	(4,289		)
Balance at May 31, 2018	$	838		$	21		$	12		$	200	$	—		$	1,071

Accumulated Other Comprehensive Income (Loss) (Tables)

12 Months Ended

May 31, 2018

Equity [Abstract]

Accumulated Other Comprehensive Income (Loss)

Changes in each component of accumulated other comprehensive income (loss), net of tax, are as follows for fiscal 2018 and 2017:



(in thousands)	Foreign currency translation gain (loss)			Unrealized gain (loss) on marketable securities			Total
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	)
Other comprehensive income before reclassifications, net of tax	270			102			372
Amounts reclassified from accumulated other comprehensive income	—			—			—
Net other comprehensive income	$	270		$	102		$	372
Balance at May 31, 2018	$	(1,035	)	$	83		$	(952	)

Quarterly Information (unaudited) (Tables)

12 Months Ended

May 31, 2018

Quarterly Financial Information Disclosure [Abstract]

Summary of Quarterly Financial Information

Quarterly results of operations during the fiscal years ended May 31, 2018 and 2017 are as follows:



	2018
	First quarter			Second quarter		Third quarter		Fourth quarter
(in thousands, except per share data)
Net sales	$	85,411		$	86,706	$	83,851	$	88,317
Gross profit	41,229			42,731		45,448		47,467
Net income (loss) (1)	(35		)	249		14,019		2,102
Earnings (loss) per common share
Basic	0.00			0.01		0.38		0.06
Diluted	0.00			0.01		0.37		0.06



	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) (2)	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		)

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.

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

Other Assets (Details) - USD ($) $ in Millions		3 Months Ended
Other Assets (Details) - USD ($) $ in Millions	Dec. 07, 2015	Nov. 30, 2016
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]
Write-off of investment		$ 2.0

Fair Value of Financial Instruments Fair Value of Financial Instruments (Details) - USD ($) $ in Thousands	May 31, 2018	May 31, 2017
Financial Assets
Marketable securities	$ 1,317
Recurring
Financial Assets
Short-term investments	2,100
Marketable securities	1,317	$ 1,215
Total Financial Assets	3,417	1,215
Financial Liabilities
Contingent liability for acquisition earn outs	3,261	12,761
Total Financial Liabilities	3,261	12,761
Recurring \| Level 1
Financial Assets
Short-term investments	2,100
Marketable securities	0	0
Total Financial Assets	2,100	0
Financial Liabilities
Contingent liability for acquisition earn outs	0	0
Total Financial Liabilities	0	0
Recurring \| Level 2
Financial Assets
Short-term investments	0
Marketable securities	0	0
Total Financial Assets	0	0
Financial Liabilities
Contingent liability for acquisition earn outs	0	0
Total Financial Liabilities	0	0
Recurring \| Level 3
Financial Assets
Short-term investments	0
Marketable securities	1,317	1,215
Total Financial Assets	1,317	1,215
Financial Liabilities
Contingent liability for acquisition earn outs	3,261	12,761
Total Financial Liabilities	$ 3,261	$ 12,761

Fair Value of Financial Instruments Fair Value of Financial Instruments (Details 2) - USD ($) $ in Thousands	12 Months Ended
	May 31, 2018	May 31, 2017
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	$ 1,215	$ 1,653
Change in fair value of contingent consideration	0	0
Currency (gain) loss from remeasurement		0
Fair market value adjustments	102	12
Sale of securities		(450)
Contingent consideration payments	0	0
Ending balance	1,317	1,215
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	12,761	38,275
Change in fair value of contingent consideration	250	(15,261)
Currency (gain) loss from remeasurement		(153)
Fair market value adjustments	0	0
Sale of securities		0
Contingent consideration payments	(9,750)	(10,100)
Ending balance	$ 3,261	$ 12,761

Fair Value of Financial Instruments Fair Value of Financial Instruments (Details 3) $ in Thousands		3 Months Ended	12 Months Ended
	Dec. 07, 2015 USD ($)	Nov. 30, 2016 USD ($)	May 31, 2018 USD ($)	May 31, 2017 USD ($)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Purchase of non-transferable warrants	$ 2,000
Potential amount of undiscounted future contingent consideration			$ 3,300
Recurring
Summary showing the recurring fair value measurements of the contingent consideration liability
Revenue based payments			3,261	$ 12,761
Level 3 \| Recurring
Summary showing the recurring fair value measurements of the contingent consideration liability
Revenue based payments			3,261	$ 12,761
Revenue based payments \| Level 3 \| Recurring
Summary showing the recurring fair value measurements of the contingent consideration liability
Revenue based payments			$ 3,261
Revenue based payments \| Level 3 \| Recurring \| Discount Rate
Summary showing the recurring fair value measurements of the contingent consideration liability
Discount rate used in fair value calculation			0.04
Revenue based payments \| Level 3 \| Maximum \| Recurring \| Contingent Consideration Earn Out Liability
Summary showing the recurring fair value measurements of the contingent consideration liability
Probability of payment			100.00%
AngioVac Product
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Gain from reduction		$ 13,400
Discontinued Investment in TiLo Product \| Disposal Group, Disposed of by Means Other than Sale, Not Discontinued Operations, Abandonment
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Gain from reduction			$ 3,100
Discontinued Investment in TiLo Product \| Disposal Group, Disposed of by Means Other than Sale, Not Discontinued Operations, Abandonment \| In Process Research and Development
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Write-down			$ 3,600

Marketable Securities (Details) - USD ($) $ in Thousands	May 31, 2018	May 31, 2017
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	$ 1,350	$ 1,350
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(33)	(135)
Fair Value	1,317	1,215
New York State government agency obligations
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	1,350	1,350
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(33)	(135)
Fair Value	$ 1,317	$ 1,215

Marketable Securities (Details 1) - USD ($) $ in Thousands	May 31, 2018	May 31, 2017
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	$ 1,350
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	1,317
Fair Value, Total	$ 1,317

Inventories (Details) - USD ($) $ in Thousands	12 Months Ended
Inventories (Details) - USD ($) $ in Thousands	May 31, 2018	May 31, 2017
Inventories
Raw materials	$ 18,678	$ 17,563
Work in process	10,808	12,602
Finished goods	19,430	24,341
Total	48,916	54,506
Inventory valuation reserve	6,100	7,300
Japanese inventory distributor
Inventory [Line Items]
Inventory write-off	700
Acculis inventory
Inventory [Line Items]
Inventory write-off	$ 1,600	$ 2,400

Prepaid Expenses and Other (Details) - USD ($) $ in Thousands	May 31, 2018	May 31, 2017
Prepaid expenses and other
Software licenses	$ 1,043	$ 582
License fees	143	118
Trade shows	223	162
Rent	134	121
Other prepaid taxes	254	544
Medical device excise tax receivable	0	1,837
Other	2,505	2,762
Total	$ 4,302	$ 6,126

Property, Plant, and Equipment, Net (Details) - USD ($) $ in Thousands	12 Months Ended
	May 31, 2018	May 31, 2017	May 31, 2016
Property, plant and equipment
Property, plant and equipment	$ 89,607	$ 93,163
Less accumulated depreciation and amortization	(48,794)	(49,652)
Property, plant and equipment excluding land and land improvements	40,813	43,511
Land and land improvements	1,648	1,723
Property, plant and equipment, Net	42,461	45,234
Depreciation expense	4,600	6,000	$ 8,200
Building and building improvements
Property, plant and equipment
Property, plant and equipment	39,887	40,597
Machinery and equipment
Property, plant and equipment
Property, plant and equipment	22,668	25,434
Computer software and equipment
Property, plant and equipment
Property, plant and equipment	24,899	25,668
Construction in progress
Property, plant and equipment
Property, plant and equipment	$ 2,153	$ 1,464

Goodwill and Intangible Assets (Details Textual)	7 Months Ended	12 Months Ended
Goodwill and Intangible Assets (Details Textual)	Dec. 31, 2017 USD ($)	May 31, 2018 USD ($) Segment	May 31, 2017 USD ($)	May 31, 2016 USD ($)
Goodwill and Intangible Assets (Textual) [Abstract]
Number of reportable segments \| Segment		1
Goodwill impairment loss	$ 0
Goodwill, period increase (decrease)		$ 0	$ 0
Amortization expense		$ 16,635,000	$ 17,296,000	$ 17,964,000

Goodwill and Intangible Assets (Details 1) - USD ($) $ in Thousands	May 31, 2018	May 31, 2017
Indefinite-lived Intangible Assets [Line Items]
Gross carrying value, finite-lived intangible assets	$ 239,005	$ 237,684
Accumulated amortization	(108,695)	(92,009)
Net carrying value, finite-lived intangible assets	130,310	145,675
Product technologies
Indefinite-lived Intangible Assets [Line Items]
Gross carrying value, finite-lived intangible assets	147,175	147,172
Accumulated amortization	(68,880)	(59,696)
Net carrying value, finite-lived intangible assets	78,295	87,476
Customer relationships
Indefinite-lived Intangible Assets [Line Items]
Gross carrying value, finite-lived intangible assets	56,428	56,375
Accumulated amortization	(23,237)	(19,194)
Net carrying value, finite-lived intangible assets	33,191	37,181
Trademarks
Indefinite-lived Intangible Assets [Line Items]
Gross carrying value, finite-lived intangible assets	28,400	28,400
Accumulated amortization	(11,809)	(9,069)
Net carrying value, finite-lived intangible assets	16,591	19,331
Licenses
Indefinite-lived Intangible Assets [Line Items]
Gross carrying value, finite-lived intangible assets	5,752	4,487
Accumulated amortization	(4,357)	(3,821)
Net carrying value, finite-lived intangible assets	1,395	666
Distributor relationships
Indefinite-lived Intangible Assets [Line Items]
Gross carrying value, finite-lived intangible assets	1,250	1,250
Accumulated amortization	(412)	(229)
Net carrying value, finite-lived intangible assets	$ 838	$ 1,021

Goodwill and Intangible Assets (Details 2) - USD ($) $ in Thousands	May 31, 2018	May 31, 2017
Expected amortization expense
2019	$ 16,555
2020	15,001
2021	13,842
2022	12,958
2023	12,507
2024 and thereafter	59,447
Net carrying value, finite-lived intangible assets	$ 130,310	$ 145,675

Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
Income Taxes (Details) - USD ($) $ in Thousands	May 31, 2018	May 31, 2017	May 31, 2016
Income (loss) before tax expense:
U.S.	$ 6,274	$ 8,825	$ (4,444)
Non-U.S.	1,191	1,022	1,191
Income (loss) before tax expense	$ 7,465	$ 9,847	$ (3,253)

Income Taxes (Details 2) - USD ($) $ in Thousands	12 Months Ended
Income Taxes (Details 2) - USD ($) $ in Thousands	May 31, 2018	May 31, 2017	May 31, 2016
Current
Federal	$ (148)	$ 0	$ 34
State and local	152	141	103
Non U.S.	73	270	217
Current	77	411	354
Deferred	(8,947)	4,428	39,983
Income tax (benefit) expense	$ (8,870)	$ 4,839	$ 40,337

Income Taxes (Details Textual) - USD ($)	3 Months Ended	5 Months Ended	12 Months Ended
Income Taxes (Details Textual) - USD ($)	Feb. 28, 2018	May 31, 2018	May 31, 2018	May 31, 2017	May 31, 2016
Income Taxes (Textual) [Abstract]
Tax benefit due to revaluation of indefinite lived deferred tax liability	$ 9,300,000	$ 9,300,000
Estimated blended corporate income tax rate (as percent)			28.60%
Tax benefit		3,000,000
Foreign subsidiary undistributed earnings		4,900,000	$ 4,900,000	$ 5,300,000
Additional unrecognized tax benefit		500,000	500,000
Accrued interest and penalties		0	0	$ 0	$ 0
Federal
Income Taxes (Textual) [Abstract]
Net operating loss carryforwards after considering limitations of use		157,800,000	157,800,000
Tax Year 2018 To 2023 \| Federal
Income Taxes (Textual) [Abstract]
Federal and State net operating loss carryforwards		28,800,000	28,800,000
Tax Year 2027 To 2037 \| Federal
Income Taxes (Textual) [Abstract]
Net operating loss carryforwards after considering limitations of use		129,000,000	129,000,000
Tax Year 2018 To 2038 \| State
Income Taxes (Textual) [Abstract]
Federal and State net operating loss carryforwards		$ 19,100,000	$ 19,100,000

Income Taxes (Details 3) - USD ($) $ in Thousands	May 31, 2018	May 31, 2017
Deferred tax assets
Net operating loss carryforward	$ 33,880	$ 55,975
Stock-based compensation	2,421	2,653
Federal and state R&D tax credit carryforward	3,644	2,548
Inventories	1,550	2,407
Expenses incurred not currently deductible	1,714	6,522
Deferred revenue	277	1,289
Gross deferred tax asset	43,486	71,394
Deferred tax liabilities
Excess tax over book depreciation and amortization	34,044	49,158
Gross deferred tax liability	34,044	49,158
Valuation Allowance	(26,607)	(48,348)
Net deferred tax liability	(17,165)	$ (26,112)
Non-U.S.
Deferred tax assets
Expenses incurred not currently deductible	$ 80

Income Taxes (Details 4) - USD ($) $ in Thousands	12 Months Ended
Income Taxes (Details 4) - USD ($) $ in Thousands	May 31, 2018	May 31, 2017	May 31, 2016
Reasons for consolidated income tax provision
Effective income tax rate (as percent)	28.60%	35.00%	35.00%
Income tax (benefit) expense at statutory tax rate of 28.6%, 35.0% and 35.0%, respectively	$ 2,136	$ 3,447	$ (1,139)
Effect of graduated tax rates	0	(98)	33
State income taxes, net of Federal tax benefit	120	(22)	(215)
Impact of Non US operations	(288)	403	(162)
Research and development tax credit	(951)	(403)	(499)
Impact of tax reform	10,912	0	0
Meals and entertainment	242	266	329
Nondeductible interest on contingent payments	0	174	262
Nontaxable gain on revaluation of contingent consideration liability	0	(5,576)	(170)
Change in valuation allowance	(21,741)	6,139	40,685
Effect of elimination of stock compensation APIC pool	0	1,380	739
Nondeductible stock-based compensation	0	(1,224)	0
Other	700	353	474
Income tax (benefit) expense	$ (8,870)	$ 4,839	$ 40,337

Income Taxes Income Taxes (Details 5) - USD ($) $ in Thousands	12 Months Ended
	May 31, 2018	May 31, 2017	May 31, 2016
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Unrecognized tax benefits, beginning balance	$ 899	$ 899	$ 0
Increase in gross amounts of tax positions related to prior years	0	0	899
Decrease in gross amounts of tax positions related to prior years due to U.S. tax reform	(287)	0	0
Decrease due to lapse in statute of limitations	(148)	0	0
Unrecognized tax benefits, ending balance	$ 464	$ 899	$ 899

Accrued Liabilities (Details) - USD ($) $ in Thousands	May 31, 2018	May 31, 2017
Accrued liabilities
Payroll and related expenses	$ 10,235	$ 11,383
Royalties	1,537	2,885
Accrued severance	1,940	2,075
Sales and franchise taxes	683	856
Outside services	2,396	1,622
Litigation matters (Note 15)	12,500	12,500
Acculis recall liability	0	2,563
Other	5,135	4,920
Total	$ 34,426	$ 38,804

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

Long-Term Debt (Details Textual) - USD ($)		12 Months Ended
Long-Term Debt (Details Textual) - USD ($)	Nov. 07, 2016	May 31, 2018	May 31, 2017	May 31, 2016	May 24, 2018
Debt Instrument [Line Items]
Proceeds from issuance of and borrowings on long-term debt		$ 0	$ 116,471,000	$ 0
Repayment of long-term debt		$ (5,000,000)	$ (140,381,000)	$ (16,250,000)
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		3.41%
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
Maximum cash amount that can be utilized to calculate net debt	$ 10,000,000.0				$ 20,000,000.0
JPMorgan Chase Bank, N.A., Bank of America, N.A., Keybank National Association \| Line of Credit \| Maximum
Debt Instrument [Line Items]
Commitment fee percentage	0.35%
JPMorgan Chase Bank, N.A., Bank of America, N.A., Keybank National Association \| Line of Credit \| Minimum
Debt Instrument [Line Items]
Commitment fee percentage	0.20%
JPMorgan Chase Bank, N.A., Bank of America, N.A., Keybank National Association \| Line of Credit \| Base Rate \| Maximum
Debt Instrument [Line Items]
State interest rate	1.25%
JPMorgan Chase Bank, N.A., Bank of America, N.A., Keybank National Association \| Line of Credit \| Base Rate \| Minimum
Debt Instrument [Line Items]
State interest rate	0.50%
JPMorgan Chase Bank, N.A., Bank of America, N.A., Keybank National Association \| Line of Credit \| Eurodollar \| Maximum
Debt Instrument [Line Items]
State interest rate	2.25%
JPMorgan Chase Bank, N.A., Bank of America, N.A., Keybank National Association \| Line of Credit \| Eurodollar \| Minimum
Debt Instrument [Line Items]
State interest rate	1.50%
JPMorgan Chase Bank, N.A., Bank of America, N.A., Keybank National Association \| Line of Credit \| Former Credit Agreement
Debt Instrument [Line Items]
Repayment of long-term debt	$ (116,500,000)
JPMorgan Chase Bank, N.A., Bank of America, N.A., Keybank National Association \| Line of Credit \| Secured Debt
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 \| Line of Credit \| Revolving Credit Facility
Debt Instrument [Line Items]
Credit facility borrowing capacity	150,000,000
Proceeds from issuance of and borrowings on long-term debt	16,500,000
JPMorgan Chase Bank, N.A., Bank of America, N.A., Keybank National Association \| Line of Credit \| Letter 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 \| Line of Credit \| Bridge Loan
Debt Instrument [Line Items]
Credit facility borrowing capacity	$ 5,000,000

Long-Term Debt (Details1) - USD ($) $ in Thousands	May 31, 2018	May 31, 2017
Future minimum principal payments on long-term debt
Total debt	$ 92,500
Less: Unamortized debt issuance costs	(879)
Total	91,621
Less: Current portion of long-term debt	(5,000)	$ (5,000)
Total long-term debt, net of current portion	86,621
Line of Credit \| Secured Debt
Future minimum principal payments on long-term debt
2019	5,000
2020	7,500
2021	11,250
2022	68,750
Total debt	92,500
Line of Credit \| Revolving Credit Facility
Future minimum principal payments on long-term debt
Total debt	$ 0

Retirement Plans (Details) - USD ($) $ in Millions	12 Months Ended
Retirement Plans (Details) - USD ($) $ in Millions	May 31, 2018	May 31, 2017	May 31, 2016
Retirement Plans (Textual) [Abstract]
Matching contributions	$ 3.9	$ 4.2	$ 3.7

Stockholders' Equity (Details Textual)				1 Months Ended	3 Months Ended		12 Months Ended
Stockholders' Equity (Details Textual)	Nov. 06, 2016 USD ($)	Oct. 25, 2016 shares	Oct. 29, 2014 $ / shares shares	Feb. 28, 2017 USD ($) $ / shares shares	May 31, 2017 USD ($) $ / shares shares	Nov. 30, 2016 USD ($) shares	May 31, 2018 USD ($) working_hour Employees $ / shares shares	May 31, 2017 USD ($) $ / shares shares	May 31, 2016 USD ($) $ / shares shares	May 31, 2015 shares
Other Ownership Interests [Line Items]
Authorized capital stock (shares) \| shares			80,000,000
Shares of common stock (shares) \| shares			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
Preferred stock, shares authorized (shares) \| shares			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
Common stock, votes per share			1
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							$ 4.95	$ 4.70	$ 4.16
Risk free interest rate							2.08%	1.30%	1.48%
Expected volatility rate							30.00%	31.00%	31.00%
Expected term							4 years 8 months 20 days	4 years 9 months 20 days	4 years 9 months 21 days
Dividends \| $							$ 0	$ 0	$ 0
The total intrinsic value of options exercised \| $							700,000	2,800,000	100,000
Compensation not yet recognized \| $							3,900,000
Proceeds from stock options exercised \| $							2,000,000	9,900,000	1,300,000
Tax benefit \| $							$ 1,800,000	$ 2,200,000	$ 1,000,000
Grants in the period, weighted average grant date fair value (usd per share) \| $ / shares								$ 16.54	$ 15.21
Average price of share issued \| $ / shares					$ 11.00		$ 14.03	$ 11.00	$ 10.67
Common stock repurchased \| $								$ 13,557,000
Repurchase of common stock \| $					$ 5,700,000		$ 0	13,557,000	$ 0
Treasury stock retirement \| $								$ 0
Common Stock
Other Ownership Interests [Line Items]
Maximum number of shares to be offered under the Stock Purchase Plan \| shares							89,943	129,185	137,957
Common stock repurchased (shares) \| shares								370,000
Common stock repurchased \| $								$ (3,000)
Treasury stock retirement (shares) \| shares				642,305				(642,305)
Treasury stock retirement \| $				$ 9,900,000				$ (2,000)
Additional paid in capital
Other Ownership Interests [Line Items]
Treasury stock retirement \| $				$ 9,900,000				(9,942,000)
Common Stock
Other Ownership Interests [Line Items]
Share repurchases, authorized amount \| $	$ 25,000,000
Share repurchase program period	24 months
Common stock repurchased (shares) \| shares						500,000
Common stock repurchased \| $						$ 7,800,000
Share repurchases \| shares					370,000
Share repurchases, remaining shares \| $							$ 11,400,000
Employee Stock Option
Other Ownership Interests [Line Items]
Percentage of grants to employees vesting							25.00%
Option grants to employees vesting period							4 years
Period of recognition for costs not yet recognized							4 years
Tax benefit \| $							$ 0	$ 0	$ 100,000
Restricted Stock Units
Other Ownership Interests [Line Items]
Period of recognition for costs not yet recognized							3 years
Vesting percentage (as percent)							25.00%
Vesting period							1 year
Grants in the period, weighted average grant date fair value (usd per share) \| $ / shares							$ 16.60
Employee service, compensation cost not yet recognized \| $							$ 5,100,000
Nonvested compensation, weighted average grant date fair value (usd per share) \| $ / shares					$ 15.55		$ 16.23	$ 15.55
Nonvested compensation (shares) \| shares					439,297		474,502	439,297
Performance Share and Restricted Stock Unit Awards
Other Ownership Interests [Line Items]
Total fair value of restricted stock awards vesting \| $							$ 2,700,000	$ 2,900,000	$ 2,500,000
Performance Shares
Other Ownership Interests [Line Items]
Employee service, compensation cost not yet recognized \| $							$ 3,900,000
Nonvested compensation, weighted average grant date fair value (usd per share) \| $ / shares					$ 22.61		$ 23.83	$ 22.61	$ 18.07
Performance period							3 years
Nonvested compensation (shares) \| shares							500,000
Weighted average remaining contractual term							2 years
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 reserved for issuance (shares) \| shares							7,000,000
Total number of common stock available to be issued (shares) \| shares							1,800,000
Options exercisable period							10 years
Incentive award plan to increase the minimum number of shares (shares) \| shares		250,000
2004 Stock and Incentive Award Plan \| Maximum
Other Ownership Interests [Line Items]
Total number of common stock available to be issued (shares) \| shares							800,000
Stock Purchase Plan
Other Ownership Interests [Line Items]
Total number of common stock available to be issued (shares) \| shares							1,200,000.0
Maximum number of shares to be offered \| shares							2,500,000
Share purchase periods \| Employees							2
Duration of purchase of shares							6 months
Employee eligible in participating in offering period							6 months
Working schedule of employee to participate in offering period							20 or more hours per week and more than five months in a calendar year
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) \| shares								500,000		800,000
Maximum number of shares to be offered under the Stock Purchase Plan \| shares							89,943	129,185	137,957

Stockholders' Equity (Details) $ / shares in Units, $ in Thousands	12 Months Ended
	May 31, 2018 USD ($) $ / shares shares
Schedule summarizes stock option activity
Shares Outstanding at beginning of year (shares) \| shares	1,667,443
Shares Granted (shares) \| shares	518,498
Shares Exercised (shares) \| shares	(271,344)
Shares Forfeited (shares) \| shares	(204,184)
Shares Expired (shares) \| shares	(14,000)
Shares Outstanding at end of year (shares) \| shares	1,696,413
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract]
Weighted average exercise price, Outstanding at beginning of year (usd per share) \| $ / shares	$ 15.01
Weighted average exercise price Granted (usd per share) \| $ / shares	16.78
Weighted average exercise price Exercised (usd per share) \| $ / shares	14.83
Weighted average exercise price Forfeited (usd per share) \| $ / shares	16.24
Weighted average exercise price Expired (usd per share) \| $ / shares	15.75
Weighted average exercise price, Outstanding at end of year (usd per share) \| $ / shares	$ 15.42
Shares Options exercisable at year-end (shares) \| shares	652,543
Shares Options expected to vest in future periods (shares) \| shares	1,043,870
Weighted average exercise price, Options exercisable at year end (usd per share) \| $ / shares	$ 14.41
Weighted average exercise price, Options expected to vest in future periods (usd per share) \| $ / shares	$ 16.05
Weighted average remaining contractual life	5 years 6 months 30 days
Weighted average remaining contractual life, Option exercisable at year end	3 years 5 months 23 days
Weighted average remaining contractual life, Option expected to vest in future periods	6 years 10 months 25 days
Aggregate intrinsic value, Outstanding at end of year \| $	$ 9,520
Aggregate intrinsic value, Options exercisable at year end \| $	4,321
Aggregate intrinsic value, Option expected to vest in future periods \| $	$ 5,199

Stockholders' Equity (Details 2) - $ / shares	12 Months Ended
Stockholders' Equity (Details 2) - $ / shares	May 31, 2018	May 31, 2017	May 31, 2016
Weighted Average Grant-Date Fair Value
Weighted Average Grant-Date Fair Value, Granted (usd per share)		$ 16.54	$ 15.21
Restricted Stock Units
Shares
Non-Vested Stock Award Units Beginning Balance (shares)	439,297
Non-Vested Stock Award Units, Granted (shares)	299,392
Non-Vested Stock Award Units, Vested (shares)	(158,756)
Non-Vested Stock Award Units, Cancelled (shares)	(105,431)
Non-Vested Stock Award Units Ending Balance (shares)	474,502	439,297
Weighted Average Grant-Date Fair Value
Weighted Average Grant-Date Fair Value Beginning Balance (usd per share)	$ 15.55
Weighted Average Grant-Date Fair Value, Granted (usd per share)	16.60
Weighted Average Grant-Date Fair Value, Vested (usd per share)	16.83
Weighted Average Grant-Date Fair Value, Cancelled (usd per share)	18.25
Weighted Average Grant-Date Fair Value Ending Balance (usd per share)	$ 16.23	$ 15.55
Performance Shares
Shares
Non-Vested Stock Award Units Beginning Balance (shares)	361,164
Non-Vested Stock Award Units, Granted (shares)	135,135
Non-Vested Stock Award Units, Vested (shares)	0
Non-Vested Stock Award Units, Cancelled (shares)	(44,443)
Non-Vested Stock Award Units Ending Balance (shares)	451,856	361,164
Weighted Average Grant-Date Fair Value
Weighted Average Grant-Date Fair Value Beginning Balance (usd per share)	$ 18.54
Weighted Average Grant-Date Fair Value, Granted (usd per share)	23.83
Weighted Average Grant-Date Fair Value, Vested (usd per share)	0.00
Weighted Average Grant-Date Fair Value, Cancelled (usd per share)	22.76
Weighted Average Grant-Date Fair Value Ending Balance (usd per share)	$ 19.75	$ 18.54

Stockholders' Equity (Details 3) - USD ($) $ in Thousands	12 Months Ended
Stockholders' Equity (Details 3) - USD ($) $ in Thousands	May 31, 2018	May 31, 2017	May 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock based compensation pre tax amount	$ 7,912	$ 6,183	$ 3,240
Cost of sales
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock based compensation pre tax amount	119	299	172
Research and development
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock based compensation pre tax amount	554	314	349
Sales and marketing
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock based compensation pre tax amount	1,778	1,762	1,489
General and administrative
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock based compensation pre tax amount	5,461	4,026	2,291
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	$ 0	$ (218)	$ (1,061)

Earnings Per Share (Details) - shares	12 Months Ended
Earnings Per Share (Details) - shares	May 31, 2018	May 31, 2017	May 31, 2016
Earnings Per Share [Abstract]
Basic	37,074,797	36,616,859	36,161,383
Effect of dilutive securities	464,603	342,391	0
Diluted	37,539,400	36,959,250	36,161,383
Securities excluded as their inclusion would be anti-dilutive	1,077,256	1,058,790	3,277,037

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, 2018 USD ($)	May 31, 2017 USD ($)	May 31, 2016 USD ($)
Loss Contingencies [Line Items]
Aggregate rental costs under operating leases \| $								$ 2.8	$ 2.5	$ 2.5
Reserve \| $									$ 12.5
C.R. Bard, Inc.
Loss Contingencies [Line Items]
Number of patents \| patent						3
Number of petitions filed for reexamination of patents \| Petition							3
The Utah Action
Loss Contingencies [Line Items]
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 Utah Action \| Pending Litigation
Loss Contingencies [Line Items]
Number of reexaminations (reexamination appeal) \| reexamination_appeal							2
The Utah Action \| C.R. Bard, Inc. \| Pending Litigation
Loss Contingencies [Line Items]
Number of reexaminations (reexamination appeal) \| reexamination_appeal							3
The Delaware Action
Loss Contingencies [Line Items]
Number of patents allegedly infringed (patent)				2	3

Commitments and Contingencies (Details) $ in Thousands	May 31, 2018 USD ($)
Aggregate of future annual payments under non cancelable operating leases for facilities and equipment [Abstract]
2019	$ 2,234
2020	1,829
2021	993
2022	884
2023 and thereafter	1,668
Total	$ 7,608

Commitments and Contingencies (Details 1) $ in Thousands	May 31, 2018 USD ($)
Commitments and Contingencies Disclosure [Abstract]
Purchase obligation	$ 56,201
Purchase obligation, 2019	11,751
Purchase obligation, 2020	14,243
Purchase obligation, 2021	15,485
Purchase obligation, 2022	9,189
Purchase obligation, 2023 and thereafter	5,533
Royalties	45,000
Royalties, 2019	3,000
Royalties, 2020	3,500
Royalties, 2021	3,500
Royalties, 2022	3,500
Royalties, 2023 and thereafter	31,500
Other	667
Other, 2019	167
Other, 2020	167
Other, 2021	167
Other, 2022	166
Other, 2023 and thereafter	0
Total	101,868
Total, 2019	14,918
Total, 2020	17,910
Total, 2021	19,152
Total, 2022	12,855
Total, 2023 and thereafter	$ 37,033

Segments and Geographic Information (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	May 31, 2018	Feb. 28, 2018	Nov. 30, 2017	Aug. 31, 2017	May 31, 2017	Feb. 28, 2017	Nov. 30, 2016	Aug. 31, 2016	May 31, 2018	May 31, 2017	May 31, 2016
Net sales by Product Category
Net sales	$ 88,317	$ 83,851	$ 86,706	$ 85,411	$ 86,914	$ 85,602	$ 89,029	$ 88,098	$ 344,285	$ 349,643	$ 353,890
Peripheral Vascular
Net sales by Product Category
Net sales									202,334	208,602	205,620
Vascular Access
Net sales by Product Category
Net sales									92,760	96,481	99,375
Oncology/Surgery
Net sales by Product Category
Net sales									$ 49,191	$ 44,560	$ 48,895

Segments and Geographic Information (Details 1) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	May 31, 2018	Feb. 28, 2018	Nov. 30, 2017	Aug. 31, 2017	May 31, 2017	Feb. 28, 2017	Nov. 30, 2016	Aug. 31, 2016	May 31, 2018	May 31, 2017	May 31, 2016
Net sales by Geography
Net sales	$ 88,317	$ 83,851	$ 86,706	$ 85,411	$ 86,914	$ 85,602	$ 89,029	$ 88,098	$ 344,285	$ 349,643	$ 353,890
United States
Net sales by Geography
Net sales									273,327	282,168	285,824
International
Net sales by Geography
Net sales									$ 70,958	$ 67,475	$ 68,066

Segments and Geographic Information (Details Textual)	12 Months Ended
Segments and Geographic Information (Details Textual)	May 31, 2018	May 31, 2017	May 31, 2016
Segment Reporting [Abstract]
International sales percentage of total net sales	21.00%	19.00%	19.00%
Total assets are located within the United States	99.00%

Acquisition, Restructuring and Other Items, net (Details) - USD ($) $ in Thousands	12 Months Ended
	May 31, 2018	May 31, 2017	May 31, 2016
Restructuring Cost and Reserve [Line Items]
Total	$ 15,432	$ 27,510	$ 12,591
Legal
Restructuring Cost and Reserve [Line Items]
Total	10,067	19,480	7,487
Intangible and other asset impairment
Restructuring Cost and Reserve [Line Items]
Total	0	5,604	352
Restructuring
Restructuring Cost and Reserve [Line Items]
Total	4,674	1,348	1,462
Other
Restructuring Cost and Reserve [Line Items]
Total	$ 691	$ 1,078	$ 3,290

Acquisition, Restructuring and Other Items, net (Details 1) - USD ($) $ in Thousands	12 Months Ended			16 Months Ended
	May 31, 2018	May 31, 2017	May 31, 2016	May 31, 2018
Restructuring Cost and Reserve [Line Items]
Acquisition, restructuring and other items, net	$ 15,432	$ 27,510	$ 12,591
Restructuring charges	4,674	1,348
Restructuring reserve	1,071	962	0	$ 1,071
Accrued Expenses
Restructuring Cost and Reserve [Line Items]
Restructuring reserve	1,100			1,100
Manchester, GA and Denmead, UK into Glens Falls and Queensbury, NY
Restructuring Cost and Reserve [Line Items]
Restructuring charges	4,700	1,300		$ 6,000
Legal
Restructuring Cost and Reserve [Line Items]
Acquisition, restructuring and other items, net	$ 10,067	19,480	$ 7,487
Legal \| DOJ Litigation
Restructuring Cost and Reserve [Line Items]
Acquisition, restructuring and other items, net		$ 12,500

Acquisition, Restructuring and Other Items, net (Details 2) - USD ($) $ in Thousands	12 Months Ended
	May 31, 2018	May 31, 2017
Restructuring Reserve [Roll Forward]
Restructuring Reserve, beginning of period	$ 962	$ 0
Charges	4,674	1,348
Non-cash adjustments	(276)	(108)
Cash payments	(4,289)	(278)
Restructuring Reserve, end of period	1,071	962
Termination Benefits
Restructuring Reserve [Roll Forward]
Restructuring Reserve, beginning of period	851	0
Charges	1,440	851
Non-cash adjustments	0	0
Cash payments	(1,453)	0
Restructuring Reserve, end of period	838	851
Plant Consolidation
Restructuring Reserve [Roll Forward]
Restructuring Reserve, beginning of period	111	0
Charges	2,892	494
Non-cash adjustments	(276)	(108)
Cash payments	(2,706)	(275)
Restructuring Reserve, end of period	21	111
Regulatory Filings
Restructuring Reserve [Roll Forward]
Restructuring Reserve, beginning of period	0	0
Charges	68	0
Non-cash adjustments	0	0
Cash payments	(56)	0
Restructuring Reserve, end of period	12	0
Contract Cancellation
Restructuring Reserve [Roll Forward]
Restructuring Reserve, beginning of period	0	0
Charges	200	0
Non-cash adjustments	0	0
Cash payments	0	0
Restructuring Reserve, end of period	200	0
Other Costs
Restructuring Reserve [Roll Forward]
Restructuring Reserve, beginning of period	0	0
Charges	74	3
Non-cash adjustments	0	0
Cash payments	(74)	(3)
Restructuring Reserve, end of period	$ 0	$ 0

Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	12 Months Ended
	May 31, 2018	May 31, 2017	May 31, 2016
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	$ 515,027	$ 507,228	$ 545,099
Total comprehensive income (loss), net of tax	16,707	4,475	(43,548)
Ending Balance	542,595	515,027	507,228
Foreign currency translation gain (loss)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	(1,305)	(760)
Other comprehensive income (loss) before reclassifications, net of tax	270	(545)
Amounts reclassified from accumulated other comprehensive income	0	0
Total comprehensive income (loss), net of tax	270	(545)
Ending Balance	(1,035)	(1,305)	(760)
Unrealized gain (loss) on marketable securities
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	(19)	(31)
Other comprehensive income (loss) before reclassifications, net of tax	102	12
Amounts reclassified from accumulated other comprehensive income	0	0
Total comprehensive income (loss), net of tax	102	12
Ending Balance	83	(19)	(31)
Total
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	(1,324)	(791)	(833)
Other comprehensive income (loss) before reclassifications, net of tax	372	(533)
Amounts reclassified from accumulated other comprehensive income	0	0
Total comprehensive income (loss), net of tax	372	(533)
Ending Balance	$ (952)	$ (1,324)	$ (791)

Quarterly Information (unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	May 31, 2018	Feb. 28, 2018	Nov. 30, 2017	Aug. 31, 2017	May 31, 2017	Feb. 28, 2017	Nov. 30, 2016	Aug. 31, 2016	May 31, 2018	May 31, 2017	May 31, 2016
Quarterly Financial Information Disclosure [Abstract]
Net sales	$ 88,317	$ 83,851	$ 86,706	$ 85,411	$ 86,914	$ 85,602	$ 89,029	$ 88,098	$ 344,285	$ 349,643	$ 353,890
Gross profit	47,467	45,448	42,731	41,229	42,335	43,792	45,010	45,032	176,875	176,169	174,316
Net income (loss)	$ 2,102	$ 14,019	$ 249	$ (35)	$ (12,913)	$ 2,887	$ 13,734	$ 1,300	$ 16,335	$ 5,008	$ (43,590)
Earnings (loss) per common share
Basic (usd per share)	$ 0.06	$ 0.38	$ 0.01	$ 0.00	$ (0.35)	$ 0.08	$ 0.37	$ 0.04	$ 0.44	$ 0.14	$ (1.21)
Diluted (usd per share)	$ 0.06	$ 0.37	$ 0.01	$ 0.00	$ (0.35)	$ 0.08	$ 0.37	$ 0.04	$ 0.44	$ 0.14	$ (1.21)
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Discrete tax benefit		$ 9,300
Estimated litigation liability					$ 12,500					$ 12,500
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, 2018	May 31, 2017	May 31, 2016
Allowance for deferred tax asset
Valuation and Qualifying Accounts
Balance at Beginning of Year	$ 48,348	$ 42,209	$ 1,791
Additions - Charged to costs and expenses	0	6,139	40,685
Deductions	(21,741)	0	(267)
Balance at End of Period	26,607	48,348	42,209
Allowance for sales returns and doubtful accounts
Valuation and Qualifying Accounts
Balance at Beginning of Year	2,945	4,372	3,043
Additions - Charged to costs and expenses	608	(291)	3,748
Deductions	(1,087)	(1,136)	(2,419)
Balance at End of Period	$ 2,466	$ 2,945	$ 4,372