Abiomed (ABMD) 10-K 25 May 17 2017 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Mar. 31, 2017	May 12, 2017	Sep. 30, 2016
Document And Entity Information [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Mar. 31, 2017
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	FY
Trading Symbol	ABMD
Entity Registrant Name	ABIOMED INC
Entity Central Index Key	815,094
Current Fiscal Year End Date	--03-31
Entity Well-known Seasoned Issuer	Yes
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		43,819,330
Entity Public Float			$ 5,571,835,144

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2017	Mar. 31, 2016
Current assets:
Cash and cash equivalents	$ 39,040	$ 48,231
Short-term marketable securities	190,908	163,822
Accounts receivable, net	54,055	42,821
Inventories	34,931	26,740
Prepaid expenses and other current assets	8,024	6,778
Total current assets	326,958	288,392
Long-term marketable securities	47,143	1,000
Property and equipment, net	87,777	23,184
Goodwill	31,045	33,003
In-process research and development	14,482	15,396
Long-term deferred tax assets, net	34,723	58,534
Other assets	8,286	4,422
Total assets	550,414	423,931
Current liabilities:
Accounts payable	20,620	9,381
Accrued expenses and other liabilities	37,703	28,382
Deferred revenue	10,495	8,778
Current portion of capital lease obligation	799
Total current liabilities	69,617	46,541
Other long-term liabilities	3,251	220
Contingent consideration	9,153	7,563
Long-term deferred tax liabilities	783	832
Capital lease obligation, net of current portion	15,539
Total liabilities	98,343	55,156
Commitments and contingencies (Note 11)
Stockholders' equity:
Class B Preferred Stock, $.01 par value Authorized - 1,000,000 shares; Issued and outstanding - none
Common stock, $.01 par value Authorized - 100,000,000 shares; Issued - 45,249,281 shares at March 31, 2017 and 43,973,119 shares at March 31, 2016; Outstanding - 43,673,286 shares at March 31, 2017 and 42,596,228 shares at March 31, 2016	437	426
Additional paid in capital	565,962	508,624
Accumulated deficit	(46,959)	(99,075)
Treasury stock at cost - 1,575,995 shares at March 31, 2017 and 1,376,891 shares at March 31, 2016	(46,763)	(26,660)
Accumulated other comprehensive loss	(20,606)	(14,540)
Total stockholders' equity	452,071	368,775
Total liabilities and stockholders' equity	$ 550,414	$ 423,931

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Mar. 31, 2017	Mar. 31, 2016
Statement Of Financial Position [Abstract]
Class B Preferred Stock, par value	$ 0.01	$ 0.01
Class B Preferred Stock, Authorized	1,000,000	1,000,000
Class B Preferred Stock, Issued	0	0
Class B Preferred Stock, outstanding	0	0
Common stock, par value	$ 0.01	$ 0.01
Common stock, Authorized	100,000,000	100,000,000
Common stock, Issued	45,249,281	43,973,119
Common stock, Outstanding	43,673,286	42,596,228
Treasury stock, shares	1,575,995	1,376,891

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2015
Revenue:
Product revenue	$ 445,195	$ 329,520	$ 229,950
Funded research and development	109	23	361
Total Revenue	445,304	329,543	230,311
Costs and expenses:
Cost of product revenue	70,627	50,419	39,945
Research and development	66,386	49,759	35,973
Selling, general and administrative	218,153	164,261	125,727
Costs and Expenses, Total	355,166	264,439	201,645
Income from operations	90,138	65,104	28,666
Other income:
Investment income, net	1,554	395	196
Other (expense) income, net	(349)	339	(97)
Nonoperating Income (Expense), Total	1,205	734	99
Income before income taxes	91,343	65,838	28,765
Income tax provision (benefit)	39,227	27,691	(84,923)
Net income	$ 52,116	$ 38,147	$ 113,688
Basic net income per share	$ 1.21	$ 0.90	$ 2.80
Basic weighted average shares outstanding	43,238	42,204	40,632
Diluted net income per share	$ 1.17	$ 0.85	$ 2.65
Diluted weighted average shares outstanding	44,658	44,895	42,858

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2015
Statement Of Income And Comprehensive Income [Abstract]
Net income	$ 52,116	$ 38,147	$ 113,688
Other comprehensive (loss) income:
Foreign currency translation (losses) gains	(5,855)	2,724	(16,613)
Net unrealized (losses) gain on marketable securities	(211)	66	13
Other comprehensive (loss) income	(6,066)	2,790	(16,600)
Comprehensive income	$ 46,050	$ 40,937	$ 97,088

Consolidated Statements of Stoc

Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock	Treasury Stock	Additional Paid in Capital	Accumulated Deficit	Accumulated Other Comprehensive (Loss) Income
Beginning Balance at Mar. 31, 2014	$ 168,353	$ 411	$ (16,554)	$ 436,136	$ (250,910)	$ (730)
Beginning Balance (in shares) at Mar. 31, 2014		39,916,328	1,206,367
Restricted stock units issued		$ 5		(5)
Restricted stock units issued (in shares)		543,420
Stock options exercised	10,927	$ 9		10,918
Stock options exercised (in shares)		911,553
Stock issued under employee stock purchase plan	795			795
Stock issued under employee stock purchase plan (in shares)		39,095
Stock issued to directors	76			76
Stock issued to directors (in shares)		1,954
Return of common stock to pay withholding taxes on restricted stock	(2,805)	$ (12)	$ (2,793)
Return of common stock to pay withholding taxes on restricted stock (in shares)		(76,577)	76,577
Stock compensation expense	16,520			16,520
Excess tax benefit from stock-based awards	606			606
Other comprehensive income (loss)	(16,600)					(16,600)
Net income	113,688				113,688
Ending Balance at Mar. 31, 2015	291,560	$ 413	$ (19,347)	465,046	(137,222)	(17,330)
Ending Balance (in shares) at Mar. 31, 2015		41,335,773	1,282,944
Restricted stock units issued		$ 5		(5)
Restricted stock units issued (in shares)		507,471
Stock options exercised	9,771	$ 8		9,763
Stock options exercised (in shares)		829,385
Stock issued under employee stock purchase plan	1,135			1,135
Stock issued under employee stock purchase plan (in shares)		16,772
Stock issued to directors	65			65
Stock issued to directors (in shares)		774
Return of common stock to pay withholding taxes on restricted stock	(7,313)		$ (7,313)
Return of common stock to pay withholding taxes on restricted stock (in shares)		(93,947)	93,947
Stock compensation expense	29,053			29,053
Excess tax benefit from stock-based awards	3,567			3,567
Other comprehensive income (loss)	2,790					2,790
Net income	38,147				38,147
Ending Balance at Mar. 31, 2016	$ 368,775	$ 426	$ (26,660)	508,624	(99,075)	(14,540)
Ending Balance (in shares) at Mar. 31, 2016	42,596,228	42,596,228	1,376,891
Restricted stock units issued		$ 5		(5)
Restricted stock units issued (in shares)		502,417
Stock options exercised	$ 10,660	$ 8		10,652
Stock options exercised (in shares)	755,000	754,893
Stock issued under employee stock purchase plan	$ 1,720			1,720
Stock issued under employee stock purchase plan (in shares)		18,288
Stock issued to directors	67			67
Stock issued to directors (in shares)		564
Return of common stock to pay withholding taxes on restricted stock	(20,105)	$ (2)	$ (20,103)
Return of common stock to pay withholding taxes on restricted stock (in shares)		(199,104)	199,104
Stock compensation expense	32,866			32,866
Excess tax benefit from stock-based awards	12,038			12,038
Other comprehensive income (loss)	(6,066)					(6,066)
Net income	52,116				52,116
Ending Balance at Mar. 31, 2017	$ 452,071	$ 437	$ (46,763)	$ 565,962	$ (46,959)	$ (20,606)
Ending Balance (in shares) at Mar. 31, 2017	43,673,286	43,673,286	1,575,995

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2015
Operating activities:
Net income	$ 52,116	$ 38,147	$ 113,688
Adjustments required to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	6,202	3,277	2,770
Bad debt expense	159	42	(5)
Stock-based compensation	32,866	29,053	16,520
Write-down of inventory	3,085	2,094	2,231
Excess tax benefit from stock-based awards	(12,038)	(3,567)	(606)
Deferred tax provision (benefit)	25,803	22,296	(87,094)
Change in fair value of contingent consideration	1,590	1,053	510
Changes in assets and liabilities:
Accounts receivable	(11,550)	(10,930)	(7,970)
Inventories	(12,284)	(11,473)	(6,967)
Prepaid expenses and other assets	(2,366)	(2,290)	(1,479)
Accounts payable	7,565	(2,645)	3,372
Accrued expenses and other liabilities	22,223	10,020	6,011
Deferred revenue	1,745	1,718	2,309
Net cash provided by operating activities	115,116	76,795	43,290
Investing activities:
Purchases of marketable securities	(278,501)	(260,975)	(97,658)
Proceeds from the sale and maturity of marketable securities	205,482	219,639	71,530
Acquisition of ECP and AIS, net of cash assumed			(15,697)
Purchase of other investment	(2,899)	(750)	(2,850)
Purchases of property and equipment	(50,415)	(15,624)	(5,188)
Net cash used for investing activities	(126,333)	(57,710)	(49,863)
Financing activities:
Proceeds from the exercise of stock options	10,660	9,771	10,927
Excess tax benefit from stock-based awards	12,038	3,567	606
Taxes paid related to net share settlement upon vesting of stock awards	(20,105)	(7,313)	(2,805)
Proceeds from the issuance of stock under employee stock purchase plan	1,720	1,135	795
Principal payments on capital lease obligation	(446)
Net cash provided by financing activities	3,867	7,160	9,523
Effect of exchange rate changes on cash	(1,841)	(415)	(1,465)
Net increase in cash and cash equivalents	(9,191)	25,830	1,485
Cash and cash equivalents at beginning of year	48,231	22,401	20,916
Cash and cash equivalents at end of year	39,040	48,231	22,401
Supplemental disclosure of cash flow information:
Cash paid for income taxes	1,405	848	1,215
Cash paid for interest on capital lease obligation	354
Supplemental disclosure of non-cash investing and financing activities:
Property and equipment under capital lease obligation	16,784
Property and equipment in accounts payable and accrued expenses	$ 5,692	$ 1,797	$ 193

Nature of Operations

Nature of Operations	12 Months Ended
	Mar. 31, 2017
Accounting Policies [Abstract]
Nature of Operations	Note 1. Nature of Operations Abiomed, Inc. (the “Company” or “Abiomed”) is a provider of mechanical circulatory support devices and offers a continuum of care to heart failure patients. The Company develops, manufactures and markets proprietary products that are designed to enable the heart to rest, heal and recover by improving blood flow and/or performing the pumping function of the heart. The Company’s products are used in the cardiac catheterization lab, or cath lab, by interventional cardiologists and in the heart surgery suite by heart surgeons for patients who are in need of hemodynamic support prophylactically or emergently before, during or after angioplasty or heart surgery procedures.

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Mar. 31, 2017
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Note 2. Summary of Significant Accounting Policies The accompanying consolidated financial statements reflect the application of significant accounting policies described below. Principles of Consolidation The accompanying consolidated financial statements include the accounts of the Company and its wholly owned subsidiaries. All intercompany accounts and transactions have been eliminated in consolidation. Use of Estimates The preparation of financial statements in conformity with generally accepted accounting principles of the United States of America, or GAAP, requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenue and expenses during the reporting period. The Company bases its estimates on historical experience and various other factors believed to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying value of assets and liabilities that are not readily apparent from other sources. On an ongoing basis, the Company evaluates its estimates, including those related to revenue recognition, collectability of receivables, realizability of inventory, property and equipment, goodwill, intangible and other long-lived assets, accrued expenses, stock-based compensation, income taxes including deferred tax assets and liabilities, contingencies and litigation. Provisions for depreciation are based on their estimated useful lives using the straight-line method. Some of these estimates can be subjective and complex and, consequently, actual results may differ from these estimates under different assumptions or conditions. Cash Equivalents and Marketable Securities The Company classifies any marketable security with a maturity date of 90 days or less at the time of purchase as a cash equivalent. Cash equivalents are carried on the balance sheet at fair market value. The Company classifies any marketable security with a maturity date of greater than 90 days at the time of purchase as marketable securities and classifies marketable securities with a maturity date of greater than one year from the balance sheet date as long-term marketable securities. Marketable securities that the Company has the positive intent and ability to hold to maturity are reported at amortized cost and classified as held-to-maturity marketable securities. If the Company does not have the intent and ability to hold a marketable security to maturity, it reports the investment as available-for-sale marketable securities. The Company reports available-for-sale marketable securities at fair value, and includes unrealized gains and, to the extent deemed temporary, unrealized losses in stockholders’ equity. If any adjustment to fair value reflects a decline in the value of the investment, the Company considers available evidence to evaluate whether the decline is “other than temporary” and, if so, marks the marketable security to market through a charge to unrealized loss on short-term marketable securities in the consolidated statements of operations. Major Customers and Concentrations of Credit Risk The Company primarily sells its products to hospitals and distributors. No customer accounted for more than 10% of total product revenues in fiscal years ended March 31, 2017, 2016 or 2015. No individual customer had an accounts receivable balance greater than 10% of total accounts receivable at March 31, 2017 and 2016. Credit is extended based on an evaluation of a customer’s historical financial condition and generally collateral is not required. To date, credit losses have not been significant and the Company maintains an allowance for doubtful accounts based on its assessment of the collectability of accounts receivable. Accounts receivables are geographically dispersed, primarily throughout the U.S., as well as in Europe and other foreign countries where formal distributor agreements exist in certain countries. Financial instruments which potentially subject the Company to a concentration of credit risk consist of cash, cash equivalents, marketable securities, short and long-term marketable securities and accounts receivable. Management mitigates credit risk by limiting the investment type and maturity to securities that preserve capital, maintain liquidity and have a high credit quality. Financial Instruments The Company’s financial instruments are comprised of cash and cash equivalents, accounts receivable, accounts payable and accrued expenses, the carrying amounts of which approximate fair market value as they are highly liquid and primarily short term in nature. Inventories Inventories are stated at the lower of cost or market. Cost is based on the first in, first out method. The Company regularly reviews inventory quantities on hand and writes down to its net realizable value any inventory that it believes to be impaired. Management considers forecast demand in relation to the inventory on hand, competitiveness of product offerings, market conditions and product life cycles when determining excess and obsolescence and net realizable value adjustments. Once inventory is written down and a new cost basis is established, it is not written back up if demand increases. Property and Equipment Property and equipment is recorded at cost less accumulated depreciation. Land is carried at cost. Depreciation is computed using the straight line method based on estimated useful lives of three to five years for machinery and equipment, computer software, and furniture and fixtures. Building and building improvements are depreciated using the straight-line method over estimated useful lives of seven to thirty-three years. Leasehold improvements are amortized using the straight-line method over the shorter of the lease term or the estimated useful lives of the related assets. Expenditures for maintenance and repairs are expensed as incurred. Upon retirement or other disposition of assets, the costs and related accumulated depreciation are eliminated from the accounts and the resulting gain or loss is reflected in operating expenses. Property and equipment is reviewed for impairment losses whenever events or changes in circumstances indicate the carrying amount may not be recoverable. An impairment loss would be recognized based on the amount by which the carrying value of the asset or asset group exceeds its fair value. Fair value is determined primarily using the estimated future cash flows associated with the asset or asset group under review discounted at a rate commensurate with the risk involved and other valuation techniques. Leases Lease agreements are evaluated to determine whether they are capital or operating leases in accordance with Financial Accounting Standards Board (“ASC”) 840, Leases Rent expense for operating leases, which may include free rent or fixed escalation amounts in addition to minimum lease payments, is recognized on a straight-line basis over the duration of each lease term. Goodwill Goodwill is recorded when consideration for an acquisition exceeds the fair value of the net tangible and intangible assets acquired. Goodwill is not amortized, instead the Company evaluates goodwill for impairment at least annually at October 31, as well as whenever events or changes in circumstances suggest that the carrying amount may not be recoverable. Goodwill impairment assessments are performed at the reporting unit level. The goodwill test involves a two-step process. The first step is a comparison of the reporting unit’s fair value to its carrying value. If the reporting unit’s fair value exceeds its carrying value, no further procedures are required. However, if the reporting unit’s fair value is less than the carrying value, an impairment of goodwill may exist, requiring a second step to measure the amount of impairment loss. If the implied fair value of goodwill is less than the recorded goodwill, an impairment charge is recorded for the difference. In applying the goodwill impairment test, the Company may assess qualitative factors to determine whether it is more likely than not that the fair value of the reporting unit is less than its carrying value. Qualitative factors may include, but are not limited to, macroeconomic conditions, industry conditions, the competitive environment, changes in the market for our products and services, regulatory and political developments, cost factors, and entity specific factors such as strategies and overall financial performance. If, after assessing these qualitative factors, the Company determines it is not more likely than not that the fair value of a reporting unit is less than its carrying value, then performing the two-step impairment test is unnecessary. The goodwill impairment test is performed at the reporting unit level by comparing the reporting unit’s carrying value, including goodwill, to the fair value of the reporting unit. The Company estimates the fair value of its single reporting unit using a combination of the income approach and the market approach. The income approach incorporates the use of a discounted cash flow method in which the estimated future cash flows and terminal values for the reporting unit is discounted to a present value using an appropriate discount rate. Cash flow projections are based on management’s estimates of economic and market conditions which drive key assumptions of revenue growth rates, operating margins, cash flows, capital expenditures and working capital requirements. The discount rate is based on the specific risk characteristics of the reporting unit and its underlying forecast. The market approach estimates fair value by comparing publicly traded companies with similar operating and investment characteristics as the reporting unit. The fair values determined by the market approach and income approach, are weighted to determine the fair value for the reporting unit based primarily on the similarity of the operating and investment characteristics of the reporting unit to the comparable publicly traded companies used in the market approach. In-Process Research and Development In-process research and development, or IPR&D, assets are considered to be indefinite-lived until the completion or abandonment of the associated research and development projects. IPR&D assets represent the fair value assigned to technologies that are acquired, which at the time of acquisition have not reached technological feasibility and have no alternative future use. During the period that the IPR&D assets are considered indefinite-lived, they are tested for impairment on an annual basis on October 31, or more frequently if the Company becomes aware of any events occurring or changes in circumstances that indicate that the fair value of the IPR&D assets are less than their carrying values. If and when development is complete, which generally occurs upon regulatory approval and the Company is able to commercialize products associated with the IPR&D assets, these assets are then deemed definite-lived and are amortized based on their estimated useful lives at that point in time. If development is terminated or abandoned, the Company may have a full or partial impairment charge related to the IPR&D assets, calculated as the excess of carrying value of the IPR&D assets over fair value. Contingent Consideration Contingent consideration represents potential milestones that the Company could pay additional consideration for associated with an acquisition and is recorded as a liability and is measured at fair value using a combination of 1) an income approach, based on various revenue and cost assumptions and applying a probability to each outcome and 2) a Monte-Carlo valuation model that simulates outcomes based on management estimates. For the clinical and regulatory milestone, p robabilities were applied to each potential scenario and the resulting values were discounted using a rate that considers the weighted average cost of capital, the related projections, and the overall business. The r evenue-based milestone is valued using a Monte-Carlo valuation model, which simulates estimated future revenues during the earn out-period using management's best estimates. During the quarter ended December 31, 2016, the Company revised the valuation method used to value the revenue-based milestone from a probability-weighted income approach to a Monte-Carlo valuation method as it believes that this method provides a more refined estimate of the contingent consideration related to this milestone based on the facts and circumstances at this time. The revision did not have a material impact on the Company’s consolidated financial statements for any period. Accrued Expenses As part of the process of preparing its financial statements, the Company is required to estimate accrued expenses. This process includes identifying services that third parties have performed and estimating the level of service performed and the associated cost incurred on these services as of each balance sheet date in its financial statements. Examples of estimated accrued expenses include contract service fees, such as amounts due to clinical research organizations, investigators in conjunction with clinical trials, professional service fees, such as attorneys and accountants, and third party expenses relating to marketing efforts associated with commercialization of the Company’s product and product candidates. Accrued expenses also include estimates for payroll costs, such as bonuses and commissions. In the event that the Company does not identify certain costs that have been incurred or it under or over-estimates the level of services or the costs of such services, reported expenses for a reporting period could be overstated or understated. The dates in which certain services commence and end, the level of services performed on or before a given date and the cost of services is often subject to the Company’s judgment. The Company makes these judgments and estimates based upon known facts and circumstances. Revenue Recognition The Company recognizes revenue when evidence of an arrangement exists, title has passed or services have been rendered, the selling price is fixed or determinable and collectability is reasonably assured. Revenue from product sales to customers is recognized when delivery has occurred. All costs related to product sales are recognized at time of delivery. The Company does not provide for rights of return to customers on product sales and therefore does not record a provision for returns. Maintenance and service support contract revenues are included in product revenue and are recognized ratably over the term of the service contracts. Revenue is recognized as earned in limited instances where the Company rents its console medical devices on a month-to-month basis or for a longer specified period of time to customers. Government-sponsored research and development contracts and grants generally provide for payment on a cost-plus-fixed-fee basis. Revenues from these contracts and grants are recognized as work is performed, provided the government has appropriated sufficient funds for the work. Under contracts in which the Company elects to spend significantly more on the development project during the term of the contract than the total contract amount, the Company prospectively recognizes revenue on such contracts ratably over the term of the contract as related research and development costs are incurred. Product Warranty The Company generally provides a one-year warranty for certain products sold in which estimated contractual warranty obligations are recorded as an expense at the time of shipment. The Company’s products are subject to regulatory and quality standards. Future warranty costs are estimated based on historical product performance rates and related costs to repair given products. The accounting estimate related to product warranty expense involves judgment in determining future estimated warranty costs. Should actual performance rates or repair costs differ from estimates, revisions to the estimated warranty liability would be required. Accumulated Other Comprehensive Income (Loss) Comprehensive income (loss) is comprised of net income, plus all changes in equity of a business enterprise during a period from transactions and other events and circumstances from non-owner sources, including any foreign currency translation adjustments. These changes in equity are recorded as adjustments to accumulated other comprehensive income (loss) in the Company’s consolidated balance sheet. The components of accumulated other comprehensive income (loss) consist primarily of foreign currency translation adjustments. There were no reclassifications out of accumulated other comprehensive income (loss) during the fiscal years ended March 31, 2017, 2016 and 2015. Translation of Foreign Currencies The functional currency of the Company’s foreign subsidiaries is their local currency. The assets and liabilities of the Company’s foreign subsidiaries are translated into U.S. dollars at exchange rates in effect at the balance sheet date. Income and expense items are translated at the average exchange rates prevailing during the period. The cumulative translation effect for subsidiaries using a functional currency other than the U.S. dollar is included in accumulated other comprehensive income or loss as a separate component of stockholders’ equity. The Company’s intercompany accounts are denominated in the functional currency of the foreign subsidiary. Gains and losses resulting from the remeasurement of intercompany receivables that the Company considers to be of a long-term investment nature are recorded in accumulated other comprehensive income or loss as a separate component of stockholders’ equity, while gains and losses resulting from the remeasurement of intercompany receivables from those foreign subsidiaries for which the Company anticipates settlement in the foreseeable future are recorded in the consolidated statement of operations. The net foreign currency translation gains and losses recorded in the consolidated statements of operations for the fiscal years ended March 31, 2017, 2016 and 2015 were not significant. Net Income Per Share Basic net income per share is computed by dividing net income by the weighted average number of common shares outstanding during the fiscal year. Diluted net income per share is computed using the treasury stock method by dividing net income by the weighted average number of dilutive common shares outstanding during the fiscal year. Diluted shares outstanding is calculated by adding to the weighted average shares outstanding any potential dilutive securities outstanding for the fiscal year. Potential dilutive securities include stock options, restricted stock awards, restricted stock units, performance-based stock awards and shares to be purchased under the employee stock purchase plan. In fiscal years when a net loss is reported, all common stock equivalents are excluded from the calculation because they would have an anti-dilutive effect, meaning the loss per share would be reduced. Therefore, in periods when a loss is reported basic and dilutive loss per share are the same. Fiscal Years Ended March 31, 2017 2016 2015 Basic Net Income Per Share Net income $ 52,116 $ 38,147 $ 113,688 Weighted average shares used in computing basic net income per share 43,238 42,204 40,632 Net income per share - basic $ 1.21 $ 0.90 $ 2.80 Fiscal Years Ended March 31, 2017 2016 2015 Diluted Net Income Per Share Net income $ 52,116 $ 38,147 $ 113,688 Weighted average shares used in computing basic net income per share 43,238 42,204 40,632 Effect of dilutive securities 1,420 2,691 2,226 Weighted average shares used in computing diluted net income per share 44,658 44,895 42,858 Net income per share - diluted $ 1.17 $ 0.85 $ 2.65 For the fiscal years ended March 31, 2017, 2016 and 2015, approximately 24,000, 62,000 and 2,000 shares of common stock underlying outstanding securities primarily related to out-of-the-money stock options and performance-based awards where milestones were not met were not included in the computation of diluted earnings per share because their inclusion would be anti-dilutive. Stock-Based Compensation The Company’s stock-based compensation cost is measured at the grant date based on the fair value of the award and is recognized as an expense over the requisite service period, and includes an estimate of awards that will be forfeited. The fair value of stock option grants is estimated using the Black-Scholes option pricing model. Use of the valuation model requires management to make certain assumptions with respect to selected model inputs. The risk-free interest rate is based on the U.S. Treasury yield curve in effect at the time of grant for a term consistent with the expected life of the stock options. Volatility assumptions are calculated based on historical volatility of the Company’s stock. The Company estimates the expected term of options based on historical exercise experience and estimates of future exercises of unexercised options. In addition, an expected dividend yield of zero is used in the option valuation model because the Company does not pay cash dividends and does not expect to pay any cash dividends in the foreseeable future. Forfeitures are estimated based on an analysis of actual forfeitures, adjusted to the extent historical forfeitures may not be indicative of expected forfeitures in the future. For awards with service conditions only, the Company recognizes stock-based compensation expense on a straight-line basis over the requisite service period. For awards with service and performance conditions, the Company recognizes stock-based compensation expense using the graded vesting method over the requisite service period. Estimates of stock-based compensation expense for an award with performance conditions are based on the probable outcome of the performance conditions. The cumulative effect of changes in the probability outcomes are recorded in the period in which the changes occur. For awards with market-based conditions, the Company uses a Monte Carlo simulation model to estimate that the grant-date fair value. The fair value related to market-based awards is recorded as stock-based compensation expense over the vesting period regardless of whether the market condition is achieved or not. Income Taxes The Company’s provision for income taxes is comprised of a current and a deferred provision. The current income tax provision is calculated as the estimated taxes payable or refundable on income tax returns for the current fiscal year. The deferred income tax provision is calculated for the estimated future income tax effects attributable to temporary differences and carryforwards using expected tax rates in effect in the years during which the differences are expected to reverse. Deferred income taxes are recognized for the tax consequences in future years as the differences between the tax bases of assets and liabilities and their financial reporting amounts at each fiscal year end based on enacted tax laws and statutory tax rates applicable to the periods in which the differences are expected to impact taxable income. The Company regularly assesses its ability to realize its deferred tax assets. Assessing the realization of deferred tax assets requires significant management judgment. Valuation allowances are established when necessary to reduce net deferred tax assets to the amount that is more likely than not to be realized. The Company recognizes and measures uncertain tax positions using a two-step approach. The first step is to evaluate the tax position for recognition by determining if, based on the technical merits, it is more likely than not that the position will be sustained upon audit, including resolution of related appeals or litigation processes, if any. The second step is to measure the tax benefit at the largest amount that is more likely than not of being realized upon ultimate settlement. The Company reevaluates these uncertain tax positions on an ongoing basis, when applicable. This evaluation is based on factors including, but not limited to, changes in facts or circumstances, new information and technical insights, and changes in tax laws. Any changes in these factors could result in the recognition of a tax benefit or an additional charge to the tax provision. When applicable, the Company accrues for the effects of uncertain tax positions and the related potential penalties and interest through income tax expense. Recent Accounting Pronouncements In March 2016, the FASB issued ASU 2016-09, Compensation-Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting In May 2014, the FASB issued ASU 2014-09, Revenue from Contracts with Customers In February 2016, the FASB issued ASU 2016-02, Leases

Marketable Securities and Fair

Marketable Securities and Fair Value Measurements	12 Months Ended
	Mar. 31, 2017
Fair Value Disclosures [Abstract]
Marketable Securities and Fair Value Measurements	Note 3. Marketable Securities and Fair Value Measurements Marketable Securities The Company’s marketable securities are classified as available-for-sale securities and, accordingly, are recorded at fair value. The difference between amortized cost and fair value is reported as a component of other comprehensive income (loss). The Company’s marketable securities at March 31, 2017 and 2016 are classified on the balance sheet as follows: March 31, 2017 March 31, 2016 (in $000's) Short-term marketable securities (within one year to maturity) $ 190,908 $ 163,822 Long-term marketable securities (one to two years to maturity) 47,143 1,000 $ 238,051 $ 164,822 The Company’s marketable securities at March 31, 2017 and 2016 are invested in the following: Amortized Gross Unrealized Gross Unrealized Fair Market Cost Gains Losses Value (in $000's) March 31, 2017: Short-term U.S. Treasury mutual fund securities $ 45,199 $ — $ (13 ) $ 45,186 Short-term government-backed securities 90,199 1 (87 ) 90,113 Short-term corporate debt securities 55,465 — (31 ) 55,434 Long-term U.S. Treasury mutual fund securities 1,998 — (3 ) 1,995 Long-term government-backed securities 43,484 5 (18 ) 43,471 Long-term corporate debt securities 1,853 — (1 ) 1,852 $ 238,198 $ 6 $ (153 ) $ 238,051 Amortized Gross Unrealized Gross Unrealized Fair Market Cost Gains Losses Value (in $000's) March 31, 2016: U.S. Treasury mutual fund securities $ 45,635 $ 21 $ — $ 45,656 Short-term government-backed securities 118,125 45 (4 ) 118,166 Long-term government-backed securities 999 1 — 1,000 $ 164,759 $ 67 $ (4 ) $ 164,822 Fair Value Hierarchy Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. Financial assets and liabilities carried at fair value are to be classified and disclosed in one of the following three categories: Level 1: Quoted market prices in active markets for identical assets or liabilities. Level 2: Observable market based inputs or unobservable inputs that are corroborated by market data. Level 3: Unobservable inputs that are not corroborated by market data. Level 1 primarily consists of financial instruments whose value is based on quoted market prices such as exchange-traded instruments and listed equities. Level 2 includes financial instruments that are valued using models or other valuation methodologies. These models are primarily industry-standard models that consider various assumptions, including time value, yield curve, volatility factors, prepayment speeds, default rates, loss severity, current market and contractual prices for the underlying financial instruments, as well as other relevant economic measures. Substantially all of these assumptions are observable in the marketplace, can be derived from observable data or are supported by observable levels at which transactions are executed in the marketplace. Level 3 is comprised of unobservable inputs that are supported by little or no market activity. Financial assets are considered Level 3 when their fair values are determined using pricing models, discounted cash flows or similar techniques and at least one significant model assumption or input is unobservable. The following table presents the Company’s fair value hierarchy for its financial instruments measured at fair value as of March 31, 2017 and 2016: Level 1 Level 2 Level 3 Total March 31, 2017: (in $000's) Assets Short-term U.S. Treasury mutual fund securities $ — $ 45,186 $ — $ 45,186 Short-term government-backed securities — 90,113 — 90,113 Short-term corporate debt securities — 55,434 — 55,434 Long-term U.S. Treasury mutual fund securities — 1,995 — 1,995 Long-term government-backed securities — 43,471 — 43,471 Long-term corporate debt securities — 1,852 — 1,852 Liabilities Contingent consideration — — 9,153 9,153 Level 1 Level 2 Level 3 Total March 31, 2016: (in $000's) Assets U.S. Treasury mutual fund securities $ — $ 45,656 $ — $ 45,656 Short-term government-backed securities — 118,166 — 118,166 Long-term government-backed securities — 1,000 — 1,000 Liabilities Contingent consideration — — 7,563 7,563 The Company has determined that the estimated fair value of its investments in U.S. Treasury mutual fund securities, government-backed securities, and corporate debt securities are reported as Level 2 financial assets as they are not exchange-traded instruments. The Company’s financial liabilities consisted of contingent consideration potentially payable related to the acquisition of ECP Entwicklungsgesellschaft mbH (“ECP”) and AIS GmbH Aachen Innovative Solutions (“AIS”), in July 2014. robabilities were applied to each potential scenario and the resulting values were discounted using a rate that considers weighted average cost of capital as well as a specific risk premium associated with the riskiness of the earn out itself, the related projections, and the overall business. The r This liability is reported as Level 3 as the estimated fair value of the contingent consideration related to the acquisition of the ECP requires significant management judgment or estimation and is calculated using the following valuation methods: Fair Value at Weighted Average March 31, 2017 Significant (range, if (in $000's) Valuation Methodology Unobservable Input applicable) Clinical and regulatory milestone $ 5,395 Probability weighted income approach Projected fiscal year of milestone payments 2019 to 2022 Discount rate 2.6% to 3.3% Probability of occurrence Probability adjusted level of 40% for the base case scenario and 5% to 20% for various upside and downside scenarios Revenue-based milestone 3,758 Monte Carlo simulation model Projected fiscal year of milestone payments 2023 to 2035 Discount rate 18% Expected volatility for forecasted revenues 50% $ 9,153 The following table summarizes the change in fair value, as determined by Level 3 inputs, of the contingent consideration for the fiscal years ended March 31, 2017, 2016 and 2015: Fiscal Years Ended March 31, 2017 2016 2015 (in $000's) Level 3 liabilities, beginning balance $ 7,563 $ 6,510 $ — Additions — — 6,000 Payments — — — Change in fair value 1,590 1,053 510 Level 3 liabilities, ending balance $ 9,153 $ 7,563 $ 6,510 The changes in fair value of the contingent consideration were primarily due to the passage of time on the fair value measurement of milestones related to the ECP acquisition. Adjustments associated with the change in fair value of contingent consideration are included in research and development expenses in the Company’s condensed consolidated statements of operations. Significant There is no assurance that any of the conditions for the milestone payments will be met. Other Investments The Company periodically makes investments in private medical device companies that focus on heart failure and heart pump technologies. The aggregate carrying amount of the Company’s portfolio of other investments was $7.2 million and $4.4 million at March 31, 2017 and 2016, respectively, and is classified within other assets in the consolidated balance sheets. Each of these individual investments are accounted for using the cost method and are measured at fair value only if there are identified events or changes in circumstances that may have a significant adverse effect on the fair value of these investments.

Accounts Receivable

Accounts Receivable	12 Months Ended
	Mar. 31, 2017
Receivables [Abstract]
Accounts Receivable	Note 4. Accounts Receivable The components of accounts receivable are as follows: March 31, 2017 March 31, 2016 (in $000's) Trade receivables $ 54,337 $ 42,945 Allowance for doubtful accounts (282 ) (124 ) $ 54,055 $ 42,821 The following table summarizes activity in the Company's allowance for doubtful accounts: Fiscal Years Ended March 31, 2017 2016 2015 (in $000's) Balance at beginning of year $ 124 $ 177 $ 185 Additions 159 42 115 Write-offs (1 ) (95 ) (123 ) Balance at end of year $ 282 $ 124 $ 177

Inventories

Inventories	12 Months Ended
	Mar. 31, 2017
Inventory Disclosure [Abstract]
Inventories	Note 5. Inventories The components of inventories are as follows: March 31, 2017 March 31, 2016 (in $000's) Raw materials and supplies $ 9,784 $ 7,993 Work-in-progress 16,504 13,147 Finished goods 8,643 5,600 $ 34,931 $ 26,740 The Company’s inventories relate to its circulatory care product lines, primarily the Impella® product platform. Finished goods and work-in-process inventories consist of direct material, labor and overhead.

Property and Equipment

Property and Equipment	12 Months Ended
	Mar. 31, 2017
Property Plant And Equipment [Abstract]
Property and Equipment	Note 6. Property and Equipment The components of property and equipment are as follows: March 31, 2017 March 31, 2016 (in $000's) Land $ 4,046 $ - Building and building improvements 10,900 - Capital lease asset 16,784 - Leasehold improvements 34,854 11,833 Machinery and equipment 27,989 25,211 Furniture and fixtures 3,899 1,510 Construction in progress 9,257 3,712 Total cost 107,729 42,266 Less accumulated depreciation (19,952 ) (19,082 ) $ 87,777 $ 23,184 In August 2016, the Company entered into an amended lease agreement for its existing corporate headquarters in Danvers, Massachusetts (see Note 11). The Company recorded $16.8 million for this lease as a capital lease asset with depreciation expense being recorded on a straight line basis over 15 years. In December 2016, the Company entered into a purchase and sale agreement to acquire its existing European headquarters in Aachen, Germany, consisting of 33,000 square feet of space. Pursuant to the purchase and sale agreement, the Company acquired the property in February 2017. The acquisition cost for the land and building was approximately $12.6 million, with $4.0 million being recorded to land and $8.6 million being recorded to the building and building improvements. Depreciation expense related to property and equipment was $6.2 million, $3.3 million, and $2.7 million for the fiscal years ending March 31, 2017, 2016 and 2015, respectively.

Goodwill and In-Process Researc

Goodwill and In-Process Research and Development	12 Months Ended
	Mar. 31, 2017
Goodwill And Intangible Assets Disclosure [Abstract]
Goodwill and In-Process Research and Development	Note 7. Goodwill and In-Process Research and Development The carrying amount of goodwill at March 31, 2017 and 2016 was $31.0 million and $33.0 million, respectively, and has been recorded in connection with the Company’s acquisition of Impella Cardiosystems AG, or Impella, in May 2005 and ECP and AIS in July 2014. The goodwill activity is as follows: (in $000's) Balance at March 31, 2015 $ 31,534 Foreign currency translation impact 1,469 Balance at March 31, 2016 $ 33,003 Foreign currency translation impact (1,958 ) Balance at March 31, 2017 $ 31,045 The Company has no accumulated impairment losses on goodwill. The Company performed a qualitative assessment during the annual impairment review for fiscal 2017 as of October 31, 2016 and concluded that it is not more likely than not that the fair value of the Company’s single reporting unit is less than its carrying amount. Therefore, the two-step goodwill impairment test for the reporting unit was not necessary in fiscal 2017. In July 2014, the Company acquired ECP and AIS and recorded $18.5 million of IPR&D assets. The estimated fair value of the IPR&D assets was determined using a probability-weighted income approach, which discounts expected future cash flows to present value. The projected cash flows from the expandable catheter pump technology were based on certain key assumptions, including estimates of future revenue and expenses, taking into account the stage of development of the technology at the acquisition date and the time and resources needed to complete development. The Company used a discount rate of 21.5% and cash flows that have been probability adjusted to reflect the risks of product commercialization, which the Company believes are appropriate and representative of market participant assumptions. The carrying value of the Company’s IPR&D assets and the change in the balance for the fiscal years ended March 31, 2017 and 2016 is as follows: (in $000's) Balance at March 31, 2015 $ 14,711 Foreign currency translation impact 685 Balance at March 31, 2016 $ 15,396 Foreign currency translation impact (914 ) Balance at March 31, 2017 $ 14,482 The Company tests IPR&D assets for impairment at least annually, or more frequently if impairment indicators exist, by first assessing qualitative factors to determine whether it is more likely than not that the fair value of the IPR&D assets is less than its carrying amount. The Company performed its annual impairment review for fiscal 2017 as of October 31, 2016 and concluded that it is not more likely than not that the fair value of the IPR&D assets is less than its carrying amount.

Stockholders' Equity

Stockholders' Equity	12 Months Ended
	Mar. 31, 2017
Equity [Abstract]
Stockholders' Equity	Note 8. Stockholders’ Equity Class B Preferred Stock The Company has authorized 1,000,000 shares of Class B Preferred Stock, $.01 par value, of which the Board of Directors can set the designation, rights and privileges. No shares of Class B Preferred Stock have been issued or are outstanding.

Stock Award Plans and Stock-Bas

Stock Award Plans and Stock-Based Compensation	12 Months Ended
	Mar. 31, 2017
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock Award Plans and Stock-Based Compensation	Note 9. Stock Award Plans and Stock-Based Compensation Stock Award Plans The Company grants stock options and restricted stock awards to employees and others. All outstanding stock options of the Company as of March 31, 2017 were granted with an exercise price equal to the fair market value on the date of grant. Outstanding stock options, if not exercised, expire 10 years from the date of grant. 2015 Stock Incentive Plan The Company’s 2015 Stock Incentive Plan (the “2015 Plan”) authorizes the grant of a variety of equity awards to the Company’s officers, directors, employees, consultants and advisers, including awards of unrestricted and restricted stock, restricted stock units, incentive and nonqualified stock options to purchase shares of common stock, performance share awards and stock appreciation rights. The 2015 Plan provides that options may only be granted at the current market value on the date of grant. Each share of stock issued pursuant to a stock option or stock appreciation right counts as one share against the maximum number of shares issuable under the 2015 Plan, while each share of stock issued pursuant to any other type of award counts as 1.8 shares against the maximum number of shares issuable under the 2015 Plan. The Company’s policy for issuing shares upon exercise of stock options or the vesting of its restricted stock awards and restricted stock units is to issue shares of common stock at the time of exercise or conversion. At March 31, 2017, a total of approximately 3,118,000 shares were available for future issuance under the 2015 Plan. 2008 Stock Incentive Plan The Company’s 2008 Stock Incentive Plan (the “2008 Plan”) authorizes the grant of a variety of equity awards to the Company’s officers, directors, employees, consultants and advisers, including awards of unrestricted and restricted stock, restricted stock units, incentive and nonqualified stock options to purchase shares of common stock, performance share awards and stock appreciation rights. The 2008 Plan provides that options may only be granted at the current market value on the date of grant. Each share of stock issued pursuant to a stock option or stock appreciation right counts as one share against the maximum number of shares issuable under the 2008 Plan, while each share of stock currently issued pursuant to any other type of award counts as 1.58 shares against the maximum number of shares issuable under the 2008 Plan. The Company’s policy for issuing shares upon exercise of stock options or the vesting of its restricted stock awards and restricted stock units is to issue shares of common stock at the time of exercise or conversion. At March 31, 2017, a total of approximately 159,000 shares were available for future issuance under the 2008 Plan. Stock-Based Compensation The following table summarizes stock-based compensation expense by financial statement line item in the Company’s consolidated statements of operations for the fiscal years ended March 31, 2017, 2016 and 2015: Fiscal Years Ended March 31, 2017 2016 2015 (in $000's) Cost of product revenue $ 1,061 $ 895 $ 665 Research and development 6,050 3,950 3,205 Selling, general and administrative 25,755 24,208 12,650 $ 32,866 $ 29,053 $ 16,520 The components of stock-based compensation for the fiscal years ended March 31, 2017, 2016 and 2015 were as follows: Fiscal Years Ended March 31, 2017 2016 2015 (in $000's) Restricted stock units $ 26,570 $ 23,708 $ 13,539 Stock options 5,829 4,866 2,708 Employee stock purchase plan 467 479 273 $ 32,866 $ 29,053 $ 16,520 Stock Options The following table summarized stock option activity for the year ended March 31, 2017: Weighted Weighted Average Aggregate Average Remaining Intrinsic Options Exercise Contractual Value (in thousands) Price Term (years) (in thousands) Outstanding at beginning of period 2,244 $ 20.55 5.19 Granted 180 106.10 Exercised (755 ) 14.12 Cancelled and expired (23 ) 73.50 Outstanding at end of period 1,646 $ 32.09 5.46 $ 153,254 Exercisable at end of period 1,156 $ 18.26 4.36 $ 123,592 Options vested and expected to vest at end of period 1,594 $ 31.06 5.37 $ 150,056 The remaining unrecognized stock-based compensation expense for unvested stock option awards at March 31, 2017 was approximately $7.7 million, net of forfeitures, and the weighted-average period over which this cost will be recognized is 2.5 years. The aggregate intrinsic value of options exercised for fiscal years 2017, 2016 and 2015 was $74.8 million, $58.6 million and $20.0 million, respectively. The total cash received as a result of employee stock option exercises during the fiscal years ended March 31, 2017, 2016 and 2015 was approximately $10.7 million, $9.8 million and $10.9 million, respectively. The total fair value of options vested in fiscal years 2017, 2016 and 2015 was $4.0 million, $2.6 million and $2.6 million, respectively. The Company estimates the fair value of each stock option granted at the grant date using the Black-Scholes option valuation model. The weighted average grant-date fair values and weighted average assumptions used in the calculation of fair value of options granted during the fiscal years ended March 31, 2017, 2016 and 2015 was as follows: Fiscal Years Ended March 31, 2017 2016 2015 Valuation assumptions: Weighted average grant-date fair value $ 42.40 $ 29.57 $ 9.29 Risk-free interest rate 1.41 % 1.55 % 1.60 % Expected option life (years) 4.14 4.15 4.19 Expected volatility 48.9 % 49.7 % 49.3 % The risk-free interest rate is based on the U.S. Treasury yield curve in effect at the time of grant for a term consistent with the expected life of the stock options. Volatility assumptions are calculated based on the historical volatility of the Company’s stock. The Company estimates the expected term of options based on historical exercise experience and estimates of future exercises of unexercised options. An expected dividend yield of zero is used in the option valuation model because the Company does not pay cash dividends and does not expect to pay any cash dividends in the foreseeable future. The Company estimates forfeitures based on an analysis of actual historical forfeitures, adjusted to the extent historic forfeitures may not be indicative of expected forfeitures in the future. Restricted Stock Units The following table summarizes restricted stock unit activity for the fiscal year ended March 31, 2017: Number of Shares Weighted Average Grant Date Fair Value (in thousands) (per share) Restricted stock units at beginning of period 1,263 $ 57.95 Granted 366 $ 97.43 Vested (502 ) $ 35.05 Forfeited (71 ) $ 91.39 Restricted stock units at end of period 1,056 $ 80.50 The remaining unrecognized compensation expense for outstanding restricted stock units, including performance-based awards, as of March 31, 2017 was $27.4 million and the weighted-average period over which this cost will be recognized is 2.0 years. The weighted average grant-date fair value for restricted stock units granted during the fiscal years ended March 31, 2017, 2016 and 2015 was $97.43, $87.45 and $22.07 per share, respectively. The total fair value of restricted stock units vested in fiscal years 2017, 2016 and 2015 was $51.3 million, $39.6 million and $11.2 million, respectively. Performance and Market-Based Awards Restricted stock units include certain awards that vest subject to certain performance and market-based criteria. The remaining unrecognized compensation expense for outstanding performance and market-based restricted stock units as of March 31, 2017 was $15.5 million and the weighted-average period over which this cost will be recognized is 2.1 years. Performance-Based Awards In May 2016, performance-based awards of restricted stock units for the potential issuance of up to 190,890 shares of common stock were issued to certain executive officers and employees, all of which vest upon achievement of prescribed service milestones by the award recipients and performance milestones by the Company. The Company met a portion of the prescribed performance milestones in fiscal 2017 such that the remaining outstanding 132,000 shares of common stock as of March 31, 2017 will vest subject to service requirements for vesting for these employees and stock-based compensation expense is being recognized accordingly over the employee’s service term. As of March 31, 2017, the Company is recognizing compensation expense based on the probable outcome related to the prescribed performance targets on the outstanding awards. In May 2015, performance-based awards of restricted stock units for the potential issuance of 183,940 shares of common stock were issued to certain executive officers and employees, all of which vest upon achievement of prescribed service milestones by the award recipients and performance milestones by the Company. The Company met the prescribed performance milestones in fiscal 2016 such that the remaining outstanding 120,000 shares of common stock as of March 31, 2017 will vest subject to service requirements for vesting for these employees and stock-based compensation expense is being recognized accordingly over the employee’s service term. In May 2014, performance-based awards of restricted stock units for the potential issuance of 379,752 shares of common stock were issued to certain executive officers and employees, all of which vest upon achievement of prescribed service milestones by the award recipients and performance milestones by the Company. The Company met the prescribed performance milestones in fiscal 2015. As of March 31, 2017, approximately 74,000 shares of common stock underlying restricted stock units remain unvested and such restricted stock units will vest subject to service requirements for vesting for these employees. In June 2011, performance-based awards of restricted stock units for the potential issuance of 100,000 shares of common stock was issued to a certain senior executive officer of the Company that would vest upon achievement of prescribed service milestones by the award recipient and performance milestones by the Company. As of March 31, 2017, the Company has met the prescribed milestones for all 100,000 shares of this award and stock-based compensation expense has been fully recognized. Market-Based Awards In June 2015, the Company awarded certain executive officers a total of up to 322,980 market-based restricted share units, of which 281,530 units remain outstanding. These restricted stock units will vest and result in the issuance of common stock based on continuing employment and the relative ranking of the total shareholder return (“TSR”) of the Company’s common stock in relation to the TSR of the component companies in the S&P Health Care Equipment Select Industry Index over a three-year performance period based on a comparison of average closing stock prices between June 2015 and June 2018. The actual number of market-based restricted stock units that may be earned can range from 0% to 300% of the target number of shares. One-half of the market-based restricted stock units earned will vest in June 2018 and the remaining restricted stock units will vest one year thereafter provided the executive officers are still employed with the Company. In November 2016, the Company awarded an executive officer a total of up to 41,526 restricted stock units. The restricted stock units are subject to both performance-and time-based vesting. These restricted stock units will vest and result in the issuance of common stock based on continuing employment, the Company achieving positive net profits measured in the aggregate over the first four full fiscal quarters following the grant date and the relative ranking of the TSR of the Company’s common stock in relation to the TSR of the component companies in the S&P Health Care Equipment Select Industry Index over a three-year performance period based on a comparison of average closing stock prices in June 2015 and June 2018. The actual number of restricted stock units that may be earned ranges from 0% to 100% of the target number of shares. One-half of the restricted stock units will potentially vest in June 2018 based on performance criteria described above and the remaining half of the restricted stock units will vest one year thereafter. The Company used a Monte Carlo simulation model to estimate the grant-date fair value of the restricted stock units granted in June 2015 and November 2016. The fair value related to the restricted stock units is being recorded as stock compensation expense over the period from date of grant to June 2019 regardless of the actual TSR outcome achieved. The table below sets forth the assumptions used to value the market-based awards and the estimated grant-date fair value: June 2015 Awards November 2016 Awards Risk-free interest rate 1.10 % 0.90 % Dividend yield 0 % 0 % Remaining performance period (years) 1.21 1.21 Expected volatility 47.2 % 50.6 % Estimated grant date fair value (per share) $ 107.10 $ 62.55 Target performance (number of shares) 107,660 41,526 Employee Stock Purchase Plan The Company has an employee stock purchase plan, or ESPP. Under the ESPP, eligible employees, including officers and directors, who have completed at least three months of employment with the Company or its subsidiaries who elect to participate in the purchase plan instruct the Company to withhold a specified amount of the employee’s income each payroll period during a six-month payment period (the periods April 1—September 30 and October 1—March 31). On the last business day of each six-month payment period, the amount withheld is used to purchase shares of the Company’s common stock at an exercise price equal to 85% of the lower of its market price on the first business day or the last business day of the payment period. The Company recognized compensation expense of $0.5 million, $0.5 million and $0.3 million for the fiscal years ended March 31, 2017, 2016 and 2015, respectively, related to the ESPP.

Income Taxes

Income Taxes	12 Months Ended
	Mar. 31, 2017
Income Tax Disclosure [Abstract]
Income Taxes	Note 10. Income Taxes The components of the Company’s income tax provision (benefit) for the fiscal years ended March 31, 2017, 2016 and 2015 are as follows: 2017 2016 2015 (in $000's) Income before provision for income taxes: United States $ 78,172 $ 54,406 $ 22,243 Foreign 13,170 11,432 6,522 Income before income taxes $ 91,342 $ 65,838 $ 28,765 Current tax expense: Federal $ 7,313 $ 1,690 $ 464 State 5,045 2,113 424 Foreign 1,066 1,592 1,283 13,424 5,395 2,171 Deferred tax expense (benefit): Federal 23,008 18,769 (66,140 ) State (349 ) 1,284 (13,430 ) Foreign 3,144 2,243 (7,524 ) 25,803 22,296 (87,094 ) Total income tax provision (benefit) $ 39,227 $ 27,691 $ (84,923 ) The components of the Company’s net deferred taxes were as follows: March 31, 2017 2016 (in $000's) Deferred tax assets NOL carryforwards and tax credit carryforwards $ 8,814 $ 34,305 Stock-based compensation 16,560 14,879 Nondeductible reserves and accruals 10,303 8,550 Amortizable intangibles other than goodwill 1,846 2,420 Capitalized research and development — 442 Foreign NOL carryforwards 13,634 17,635 Deferred revenue 4,308 3,351 Depreciation 289 353 Other, net 1,308 1,802 57,062 83,737 Deferred tax liabilities Indefinite lived intangibles (9,444 ) (8,480 ) In-process research and development (4,374 ) (4,649 ) Domestic deferred tax liability on foreign NOL carryforwards (6,836 ) (10,488 ) (20,654 ) (23,617 ) Net deferred tax assets 36,408 60,120 Valuation allowance (2,468 ) (2,418 ) Net deferred tax assets $ 33,940 $ 57,702 Reported as: Long-term deferred tax assets, net $ 34,723 $ 58,534 Long-term deferred tax liabilities (783 ) (832 ) Net deferred tax assets $ 33,940 $ 57,702 A reconciliation of the federal statutory income tax rate to the Company’s effective income tax rate is as follows for the fiscal years ended March 31, 2017, 2016, and 2015: 2017 2016 2015 Statutory income tax rate 35.0 % 35.0 % 35.0 % Increase (decrease) resulting from: Change in valuation allowance 0.2 0.7 (342.8 ) Credits (3.3 ) (4.1 ) (1.9 ) Foreign taxes 2.0 2.5 4.5 State taxes, net 3.8 3.7 4.0 Permanent differences 3.3 3.0 3.9 Stock based compensation 0.2 0.3 0.3 Rate differential on foreign operations 0.1 - 0.2 Other 1.7 1.0 1.6 Effective tax rate 43.0 % 42.1 % (295.2 ) % 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 evaluates all available positive and negative evidence, and weights the evidence based on its objectivity. During the fiscal year ended March 31, 2015, the Company determined based on its consideration of the weight of positive and negative evidence that there was sufficient positive evidence that most of its federal, state and certain foreign deferred tax assets were more likely than not recoverable as of March 31, 2015. Accordingly, the Company recorded a $101.5 million reversal of the valuation allowance in the year ended March 31, 2015. As of March 31, 2017 and 2016, respectively, the Company maintained a valuation allowance of $2.5 million and $2.4 million for deferred tax assets related to NOL carryforwards in certain foreign jurisdictions in which the Company has had limited or no history of profitability. Based on the review of all available evidence, the Company recorded a valuation allowance to reduce these deferred tax assets to the amount that is more likely than not to be realizable as of March 31, 2017 and 2016. Changes in the valuation allowance for deferred tax assets during the fiscal years ended March 31, 2017, 2016 and 2015 were as follows: 2017 2016 2015 (in $000's) Valuation allowance as of beginning of year $ 2,418 $ 2,912 $ 102,093 Decreases recorded as benefit to income tax provision - (1,171 ) (101,468 ) Increases due to foreign net operating loss in certain foreign jurisdictions 50 677 2,287 Valuation allowance as of end of year $ 2,468 $ 2,418 $ 2,912 At March 31, 2017, the Company had federal net operating loss carryforwards, or NOLs, of approximately $167.3 million which expire in varying years from fiscal 2019 through fiscal 2035. At March 31, 2017, the Company had foreign NOLs of approximately $46.9 million, primarily in Germany, U.K., and France, which do not expire. In addition, at March 31, 2017, the Company had federal and state research and development credit carryforwards of approximately $13.7 million and $7.8 million, respectively, which expire in varying years from fiscal 2017 through fiscal 2036. The entire amount of federal NOL of $167.3 million relates to stock-based compensation tax deductions in excess of stock-based compensation expense for financial reporting purposes (“excess tax benefits”). Excess tax benefits are realized when they reduce income taxes payable, as determined using a “with and without” method, and are currently credited to additional paid-in capital rather than as a reduction of the income tax provision. During the year ended March 31, 2017, the Company realized excess tax benefits from federal and state tax deductions of $12.0 million which were credited to additional paid-in capital. As described in Note 2 above, the Company will adopt ASU 2016-09 during the first quarter of fiscal 2018. The Company believes that the adoption of ASU 2016-09 will have a significant impact on the Company’s consolidated financial statements, most notably, the requirement to recognize certain tax benefits or shortfalls upon a restricted stock unit vesting or stock option exercises in the income tax provision in the consolidated statement of operations. Upon adoption in the first quarter of fiscal 2018, the Company expects to record a cumulative-effect adjustment, on a modified-retrospective basis, within retained earnings for excess tax benefits not previously recognized as net deferred tax assets. The Company also anticipates that ASU 2016-09 will introduce more volatility to its effective income tax rate, net income and earnings per share due to the effect of tax benefits or shortfalls related to restricted stock unit vestings or stock option exercises. When applicable, the Company accrues for the effects of uncertain tax positions and the related potential penalties and interest through income tax expense. As of March 31, 2017 and 2016, the Company has no material uncertain tax positions and no interest and penalties were recognized during the years ended March 31, 2017, 2016 and 2015, respectively. The Company and its subsidiaries are subject to U.S. federal income tax, as well as income tax of multiple state and foreign jurisdictions. Fiscal years 2012 through 2016 remain open to examination in Germany and Abiomed Europe GmbH, the Company’s main operating subsidiary in Germany is currently being audited for those years. All tax years remain subject to examination by the Internal Revenue Service and state tax authorities, because the Company has net operating loss and tax credit carryforwards which may be utilized in future years to offset taxable income, those years may also be subject to review by relevant taxing authorities if the carryforwards are utilized.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Mar. 31, 2017
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	Note 11. Commitments and Contingencies Commitments Leases The Company’s corporate headquarters is located in Danvers, Massachusetts. This facility encompasses most of the Company’s U.S. operations, including research and development, manufacturing, sales and marketing and general and administrative departments. On August 12, 2016, the Company entered into a new lease agreement to expand its existing corporate headquarters which includes 163,560 square feet of space. The initial term of the lease agreement commenced on August 12, 2016 and terminates on August 31, 2026. The Company has options to extend the initial term for three separate periods of five years each. In connection with the entry into this new lease agreement, the Company terminated the previously existing lease for the facility dated February 24, 2014, as amended by the First Amendment to Lease dated April 30, 2015 and the Second Amendment to Lease effective January 1, 2016. The Company also terminated the purchase and sale agreement it had entered into to acquire the facility for $16.5 million in December 2015 when it entered into this new lease agreement in August 2016. The lease agreement provides the Company with an exclusive option to purchase the building on or before August 31, 2022, subject to certain conditions set forth therein. In addition, the lease agreement grants the Company a one-time right of first offer to purchase the building from September 1, 2022 until August 31, 2026, if the lessor decides to sell the building or receives an offer to purchase the building from a third-party buyer. The Danvers, Massachusetts building lease is being recorded as a capital lease. The payments under the lease are accounted for as interest and principal payments over 15 years. Future minimum lease payments under non-cancelable leases as of March 31, 2017 are approximately as follows: Fiscal Years Ending March 31, Capital Lease Operating Leases (in $000s) 2018 $ 1,311 $ 1,670 2019 1,349 1,593 2020 1,349 1,532 2021 1,373 1,542 2022 1,390 1,084 Thereafter 13,746 752 Total minimum lease payments 20,518 $ 8,173 Less amounts representing interest (4,180 ) Total capital lease obligation $ 16,338 Less current capital lease obligation (799 ) Capital lease obligation, net of current portion $ 15,539 In February 2017, the Company entered into a lease agreement for an additional office space in Danvers, Massachusetts which expires in July 2022. The annual rent expense for this lease agreement is estimated to be $0.2 million. In September 2016, the Company entered into a lease agreement in Berlin, Germany which commences in May 2017 and expires in May 2024. The annual rent expense for this lease agreement is estimated to be $0.3 million. The Company also entered into a lease agreement in October 2016 through September 2021 for an office in Tokyo, Japan which houses regulatory and training personnel as we prepare for commercial launch in Japan. The annual rent expense for this lease agreement is estimated to be $0.9 million. In December 2016, the Company entered into a purchase and sale agreement to acquire its existing European headquarters in Aachen, Germany, consisting of 33,000 square feet of space. Pursuant to the purchase and sale agreement, the Company acquired the property for approximately $12.6 million in February 2017. License Agreements In April 2014, the Company entered into an exclusive license agreement for the rights to certain optical sensor technologies in the field of cardio-circulatory assist devices. The Company made a $1.5 million upfront payment upon execution of the agreement and could make additional payments of up to $4.5 million upon the achievement of certain development milestones. The Company paid approximately $0.8 million in development milestones which are included with research and development expenses for the fiscal year ended March 31, 2017. Contingencies From time to time, the Company is involved in legal and administrative proceedings and claims of various types. In some actions, the claimants seek damages, as well as other relief, which, if granted, would require significant expenditures. The Company records a liability in its consolidated financial statements for these matters when a loss is known or considered probable and the amount can be reasonably estimated. The Company reviews these estimates each accounting period as additional information is known and adjusts the loss provision when appropriate. If a matter is both probable to result in liability and the amounts of loss can be reasonably estimated, the Company estimates and discloses the possible loss or range of loss. If the loss is not probable or cannot be reasonably estimated, a liability is not recorded in its consolidated financial statements. On April 25, 2014, the Company received an administrative subpoena from the Boston regional office of the United States Department of Health and Human Services, or HHS, Office of Inspector General requesting materials relating to the Company’s reimbursement of employee expenses and remuneration to healthcare providers from July 2012 through December 2012, in connection with a civil investigation under the False Claims Act (the “FCA Investigation”). Subsequently, the Company received Civil Investigative Demands from the U.S. Attorney’s Office for the District of Massachusetts that collectively sought additional information relating to this matter for the time period of January 1, 2011 through September 14, 2016. The Company continues to cooperate fully with the government in this investigation and is exploring various ways to resolve this matter with the government. The Company is not able to predict what action, if any, might be taken in the future as a result of the investigation, or the potential impact on its financial position. Thoratec Corporation, or Thoratec, has challenged a number of Company owned patents in Europe in connection with the launch of their HeartMate PHP medical device, or PHP, in Europe. These actions all relate to Thoratec’s ability to manufacture and sell their PHP product in Europe. These actions do not cover the Company’s ability to manufacture or sell its Impella line of devices. Thoratec is currently a subsidiary of Abbott Laboratories since January 2017. In October 2012, Thoratec filed a notice of opposition in the European Patent Office, or EPO, to a Company owned European patent covering a ‘pigtail’ feature on a blood pump. In October 2014, the EPO dismissed Thoratec’s opposition, and in December 2014, Thoratec filed a notice of appeal. The appeal was heard on January 20, 2017 by the EPO Board of Appeals. The Company prevailed at the EPO Board of Appeals and succeeded in upholding the patent in an amended form. The approved amended claim covers the combination of a blood pump with a pigtail and an expanding suction basket and funnel feature. The Board of Appeals is the highest level at the EPO so there are no further challenges to this patent possible at the EPO by Thoratec. In December 2014, Thoratec filed a nullity suit in German’s Patent Federal Court against a German “pigtail” patent owned by the Company with a flexible extension feature, and auxiliary pigtail, basket and funnel features. The validity hearing was held in November 2016 and the Patent Federal Court found the patent invalid. The Company is appealing this decision. In August 2015, Thoratec filed a nullity action in German Patent Federal Court against two Company owned patents covering a “magnetic clutch” feature. These magnetic clutch patents were acquired by the Company in July 2014, in connection with its acquisition of ECP and AIS. The validity hearing for the magnetic clutch patents is scheduled for June 2017; the Court’s preliminary opinion is that the magnetic clutch claims are invalid. In September 2015, the Company filed counterclaims in the magnetic clutch action in Germany asserting that the PHP product infringes the two magnetic clutch patents and the two pigtail patents. The infringement trial has been stayed, pending resolution of the German and EPO nullity actions. In December 2015, the Company received a letter from Maquet Cardiovascular LLC, or Maquet, a subsidiary of the Getinge Group, and maker of the intra-aortic balloon pump, asserting that the Company’s Impella devices infringe certain claims having guidewire, lumen and sensor features which were in two Maquet patents and one pending patent application in the U.S. and elsewhere, and attached a draft litigation complaint and encouraged the Company to take a license from Maquet. In January 2016, the Company responded to Maquet stating that it believed that the cited claims were invalid and that its Impella devices did not infringe the cited patents. In May 2016, Maquet sent an additional letter notifying the Company that the pending U.S. patent application had been issued as a U.S. patent and repeated their earlier assertion and encouraged the Company to discuss taking a license from Maquet. The three patents expire September 2020, December 2020 and October 2021. On May 19, 2016, the Company filed suit in U.S. District Court for the District of Massachusetts, or D. Mass., against Maquet seeking a declaratory judgment that the Company’s Impella devices do not infringe Maquet’s cited patent rights. On August 24, 2016, Maquet sent another letter to the Company identifying four new U.S. continuation patent filings with claims that Maquet alleges are infringed by the Company’s Impella devices. Of the four U.S. continuation applications, one issued as a patent on January 17, 2017, one issued as a patent on February 7, 2017, one issued as a patent on March 21, 2017, and one has not begun substantive prosecution. The three patent issued will expire in September 2020 and if the fourth continuation application issues it will also expire in September 2020. On September 23, 2016, Maquet filed a response to the Company’s suit in D. Mass., including various counterclaims alleging that the Company’s Impella 2.5, Impella CP, Impella 5.0, and Impella RP heart pumps infringe certain claims of the three original issued U.S. patents. The case is in its early stages and the next hearing on this case is scheduled for November 2017. With regard to the six Maquet patents, in March and April 2017 the Company filed requests for inter partes review, or IPR, at the U.S. Patent & Trademark Office’s Patent Trial and Appeals Board, or PTAB, asserting that the claims are invalid in view of prior art blood pump technology. The PTAB’s decisions on whether to institute the IPRs are expected beginning September 2017. On February 9, 2017, Thoratec filed an opposition against a Company patent acquired from ECP and AIS relating to a housing structure for an expandable pump. The deadline for the Company to respond to the opposition is in September 2017. The Company is unable to estimate a potential liability with respect to the legal matters noted above. There are numerous factors that make it difficult to meaningfully estimate possible loss or range of loss at this stage of the legal proceedings, including that the FCA Investigation and patent disputes with Thoratec and Maquet remain either in relatively early stages, or there are significant factual and legal issues to be resolved and information obtained or rulings made during any lawsuits or investigations that could affect the methodology for calculation.

Accrued Expenses

Accrued Expenses	12 Months Ended
	Mar. 31, 2017
Payables And Accruals [Abstract]
Accrued Expenses	Note 12. Accrued Expenses Accrued expenses consisted of the following: March 31, 2017 March 31, 2016 (in $000's) Employee compensation $ 23,290 $ 18,359 Sales and income taxes 3,180 2,527 Research and development 2,349 1,587 Accrued capital expenditures 2,300 - Professional, legal and accounting fees 2,019 1,764 Marketing 1,827 1,146 Warranty 717 998 Other 2,021 2,001 $ 37,703 $ 28,382 Accrued employee compensation consists primarily of accrued bonuses, accrued commissions and accrued employee benefits at March 31, 2017 and 2016.

Segment and Enterprise Wide Dis

Segment and Enterprise Wide Disclosures	12 Months Ended
	Mar. 31, 2017
Segment Reporting [Abstract]
Segment and Enterprise Wide Disclosures	Note 13. Segment and Enterprise Wide Disclosures The Company operates in one business segment—the research, development and sale of medical devices to assist or replace the pumping function of the failing heart. The Company’s chief operating decision maker (determined to be the Chief Executive Officer) does not manage any part of the Company separately, and the allocation of resources and assessment of performance are based on the Company’s consolidated operating results. International sales (sales outside the U.S. and primarily in Europe) accounted for 9%, 8% and 10% of total product revenue during the fiscal years ended March 31, 2017, 2016 and 2015, respectively. As of March 31, 2017 and 2016, most of the Company’s long-lived assets are located in the U.S. except for $23.2 million and $5.9 million at March 31, 2017 and 2016, respectively, which are located primarily in Germany. As described in Note 6 above, the Company acquired its European headquarters in Aachen, Germany in February 2017 for $12.6 million.

Quarterly Results of Operation

Quarterly Results of Operation	12 Months Ended
	Mar. 31, 2017
Quarterly Financial Information Disclosure [Abstract]
Quarterly Results of Operation	Note 14. Quarterly Results of Operation (Unaudited) The following is a summary of the Company’s unaudited quarterly results of operations for the fiscal years ending March 31, 2017 and 2016: Fiscal Year Ended March 31, 2017 1st Quarter 2nd Quarter 3rd Quarter 4th Quarter Total Year (in $000's) Total revenues $ 102,995 $ 102,955 $ 114,674 $ 124,680 $ 445,304 Cost of product revenue 15,070 17,309 18,987 19,261 70,627 Other operating expenses 66,692 71,138 70,284 76,425 284,539 Other income, net 192 228 423 362 1,205 Income before income taxes 21,425 14,736 25,826 29,356 91,343 Income tax provision 8,515 5,861 10,394 14,457 39,227 Net income $ 12,910 $ 8,875 $ 15,432 $ 14,899 $ 52,116 Basic net income per share $ 0.30 $ 0.21 $ 0.36 $ 0.34 $ 1.21 Diluted net income per share $ 0.29 $ 0.20 $ 0.34 $ 0.33 $ 1.17 Fiscal Year Ended March 31, 2016 1st Quarter 2nd Quarter 3rd Quarter 4th Quarter Total Year (in $000's) Total revenues $ 73,432 $ 76,359 $ 85,795 $ 93,957 $ 329,543 Cost of product revenue 10,868 12,144 12,744 14,663 50,419 Other operating expenses 47,533 51,398 55,608 59,481 214,020 Other income, net 116 149 55 414 734 Income before income taxes 15,147 12,966 17,498 20,227 65,838 Income tax provision 6,288 5,231 6,943 9,229 27,691 Net income $ 8,859 $ 7,735 $ 10,555 $ 10,998 $ 38,147 Basic net income per share $ 0.21 $ 0.18 $ 0.25 $ 0.26 $ 0.90 Diluted net income per share $ 0.20 $ 0.17 $ 0.23 $ 0.24 $ 0.85

Summary of Significant Accoun22

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Mar. 31, 2017
Accounting Policies [Abstract]
Principles of Consolidation	Principles of Consolidation The accompanying consolidated financial statements include the accounts of the Company and its wholly owned subsidiaries. All intercompany accounts and transactions have been eliminated in consolidation.
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with generally accepted accounting principles of the United States of America, or GAAP, requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenue and expenses during the reporting period. The Company bases its estimates on historical experience and various other factors believed to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying value of assets and liabilities that are not readily apparent from other sources. On an ongoing basis, the Company evaluates its estimates, including those related to revenue recognition, collectability of receivables, realizability of inventory, property and equipment, goodwill, intangible and other long-lived assets, accrued expenses, stock-based compensation, income taxes including deferred tax assets and liabilities, contingencies and litigation. Provisions for depreciation are based on their estimated useful lives using the straight-line method. Some of these estimates can be subjective and complex and, consequently, actual results may differ from these estimates under different assumptions or conditions.
Cash Equivalents and Marketable Securities	Cash Equivalents and Marketable Securities The Company classifies any marketable security with a maturity date of 90 days or less at the time of purchase as a cash equivalent. Cash equivalents are carried on the balance sheet at fair market value. The Company classifies any marketable security with a maturity date of greater than 90 days at the time of purchase as marketable securities and classifies marketable securities with a maturity date of greater than one year from the balance sheet date as long-term marketable securities. Marketable securities that the Company has the positive intent and ability to hold to maturity are reported at amortized cost and classified as held-to-maturity marketable securities. If the Company does not have the intent and ability to hold a marketable security to maturity, it reports the investment as available-for-sale marketable securities. The Company reports available-for-sale marketable securities at fair value, and includes unrealized gains and, to the extent deemed temporary, unrealized losses in stockholders’ equity. If any adjustment to fair value reflects a decline in the value of the investment, the Company considers available evidence to evaluate whether the decline is “other than temporary” and, if so, marks the marketable security to market through a charge to unrealized loss on short-term marketable securities in the consolidated statements of operations.
Major Customers and Concentrations of Credit Risk	Major Customers and Concentrations of Credit Risk The Company primarily sells its products to hospitals and distributors. No customer accounted for more than 10% of total product revenues in fiscal years ended March 31, 2017, 2016 or 2015. No individual customer had an accounts receivable balance greater than 10% of total accounts receivable at March 31, 2017 and 2016. Credit is extended based on an evaluation of a customer’s historical financial condition and generally collateral is not required. To date, credit losses have not been significant and the Company maintains an allowance for doubtful accounts based on its assessment of the collectability of accounts receivable. Accounts receivables are geographically dispersed, primarily throughout the U.S., as well as in Europe and other foreign countries where formal distributor agreements exist in certain countries. Financial instruments which potentially subject the Company to a concentration of credit risk consist of cash, cash equivalents, marketable securities, short and long-term marketable securities and accounts receivable. Management mitigates credit risk by limiting the investment type and maturity to securities that preserve capital, maintain liquidity and have a high credit quality.
Financial Instruments	Financial Instruments The Company’s financial instruments are comprised of cash and cash equivalents, accounts receivable, accounts payable and accrued expenses, the carrying amounts of which approximate fair market value as they are highly liquid and primarily short term in nature.
Inventories	Inventories Inventories are stated at the lower of cost or market. Cost is based on the first in, first out method. The Company regularly reviews inventory quantities on hand and writes down to its net realizable value any inventory that it believes to be impaired. Management considers forecast demand in relation to the inventory on hand, competitiveness of product offerings, market conditions and product life cycles when determining excess and obsolescence and net realizable value adjustments. Once inventory is written down and a new cost basis is established, it is not written back up if demand increases.
Property and Equipment	Property and Equipment Property and equipment is recorded at cost less accumulated depreciation. Land is carried at cost. Depreciation is computed using the straight line method based on estimated useful lives of three to five years for machinery and equipment, computer software, and furniture and fixtures. Building and building improvements are depreciated using the straight-line method over estimated useful lives of seven to thirty-three years. Leasehold improvements are amortized using the straight-line method over the shorter of the lease term or the estimated useful lives of the related assets. Expenditures for maintenance and repairs are expensed as incurred. Upon retirement or other disposition of assets, the costs and related accumulated depreciation are eliminated from the accounts and the resulting gain or loss is reflected in operating expenses. Property and equipment is reviewed for impairment losses whenever events or changes in circumstances indicate the carrying amount may not be recoverable. An impairment loss would be recognized based on the amount by which the carrying value of the asset or asset group exceeds its fair value. Fair value is determined primarily using the estimated future cash flows associated with the asset or asset group under review discounted at a rate commensurate with the risk involved and other valuation techniques.
Leases	Leases Lease agreements are evaluated to determine whether they are capital or operating leases in accordance with Financial Accounting Standards Board (“ASC”) 840, Leases Rent expense for operating leases, which may include free rent or fixed escalation amounts in addition to minimum lease payments, is recognized on a straight-line basis over the duration of each lease term.
Goodwill	Goodwill Goodwill is recorded when consideration for an acquisition exceeds the fair value of the net tangible and intangible assets acquired. Goodwill is not amortized, instead the Company evaluates goodwill for impairment at least annually at October 31, as well as whenever events or changes in circumstances suggest that the carrying amount may not be recoverable. Goodwill impairment assessments are performed at the reporting unit level. The goodwill test involves a two-step process. The first step is a comparison of the reporting unit’s fair value to its carrying value. If the reporting unit’s fair value exceeds its carrying value, no further procedures are required. However, if the reporting unit’s fair value is less than the carrying value, an impairment of goodwill may exist, requiring a second step to measure the amount of impairment loss. If the implied fair value of goodwill is less than the recorded goodwill, an impairment charge is recorded for the difference. In applying the goodwill impairment test, the Company may assess qualitative factors to determine whether it is more likely than not that the fair value of the reporting unit is less than its carrying value. Qualitative factors may include, but are not limited to, macroeconomic conditions, industry conditions, the competitive environment, changes in the market for our products and services, regulatory and political developments, cost factors, and entity specific factors such as strategies and overall financial performance. If, after assessing these qualitative factors, the Company determines it is not more likely than not that the fair value of a reporting unit is less than its carrying value, then performing the two-step impairment test is unnecessary. The goodwill impairment test is performed at the reporting unit level by comparing the reporting unit’s carrying value, including goodwill, to the fair value of the reporting unit. The Company estimates the fair value of its single reporting unit using a combination of the income approach and the market approach. The income approach incorporates the use of a discounted cash flow method in which the estimated future cash flows and terminal values for the reporting unit is discounted to a present value using an appropriate discount rate. Cash flow projections are based on management’s estimates of economic and market conditions which drive key assumptions of revenue growth rates, operating margins, cash flows, capital expenditures and working capital requirements. The discount rate is based on the specific risk characteristics of the reporting unit and its underlying forecast. The market approach estimates fair value by comparing publicly traded companies with similar operating and investment characteristics as the reporting unit. The fair values determined by the market approach and income approach, are weighted to determine the fair value for the reporting unit based primarily on the similarity of the operating and investment characteristics of the reporting unit to the comparable publicly traded companies used in the market approach.
In-Process Research and Development	In-Process Research and Development In-process research and development, or IPR&D, assets are considered to be indefinite-lived until the completion or abandonment of the associated research and development projects. IPR&D assets represent the fair value assigned to technologies that are acquired, which at the time of acquisition have not reached technological feasibility and have no alternative future use. During the period that the IPR&D assets are considered indefinite-lived, they are tested for impairment on an annual basis on October 31, or more frequently if the Company becomes aware of any events occurring or changes in circumstances that indicate that the fair value of the IPR&D assets are less than their carrying values. If and when development is complete, which generally occurs upon regulatory approval and the Company is able to commercialize products associated with the IPR&D assets, these assets are then deemed definite-lived and are amortized based on their estimated useful lives at that point in time. If development is terminated or abandoned, the Company may have a full or partial impairment charge related to the IPR&D assets, calculated as the excess of carrying value of the IPR&D assets over fair value.
Contingent Consideration	Contingent Consideration Contingent consideration represents potential milestones that the Company could pay additional consideration for associated with an acquisition and is recorded as a liability and is measured at fair value using a combination of 1) an income approach, based on various revenue and cost assumptions and applying a probability to each outcome and 2) a Monte-Carlo valuation model that simulates outcomes based on management estimates. For the clinical and regulatory milestone, p robabilities were applied to each potential scenario and the resulting values were discounted using a rate that considers the weighted average cost of capital, the related projections, and the overall business. The r evenue-based milestone is valued using a Monte-Carlo valuation model, which simulates estimated future revenues during the earn out-period using management's best estimates. During the quarter ended December 31, 2016, the Company revised the valuation method used to value the revenue-based milestone from a probability-weighted income approach to a Monte-Carlo valuation method as it believes that this method provides a more refined estimate of the contingent consideration related to this milestone based on the facts and circumstances at this time. The revision did not have a material impact on the Company’s consolidated financial statements for any period.
Accrued Expenses	Accrued Expenses As part of the process of preparing its financial statements, the Company is required to estimate accrued expenses. This process includes identifying services that third parties have performed and estimating the level of service performed and the associated cost incurred on these services as of each balance sheet date in its financial statements. Examples of estimated accrued expenses include contract service fees, such as amounts due to clinical research organizations, investigators in conjunction with clinical trials, professional service fees, such as attorneys and accountants, and third party expenses relating to marketing efforts associated with commercialization of the Company’s product and product candidates. Accrued expenses also include estimates for payroll costs, such as bonuses and commissions. In the event that the Company does not identify certain costs that have been incurred or it under or over-estimates the level of services or the costs of such services, reported expenses for a reporting period could be overstated or understated. The dates in which certain services commence and end, the level of services performed on or before a given date and the cost of services is often subject to the Company’s judgment. The Company makes these judgments and estimates based upon known facts and circumstances.
Revenue Recognition	Revenue Recognition The Company recognizes revenue when evidence of an arrangement exists, title has passed or services have been rendered, the selling price is fixed or determinable and collectability is reasonably assured. Revenue from product sales to customers is recognized when delivery has occurred. All costs related to product sales are recognized at time of delivery. The Company does not provide for rights of return to customers on product sales and therefore does not record a provision for returns. Maintenance and service support contract revenues are included in product revenue and are recognized ratably over the term of the service contracts. Revenue is recognized as earned in limited instances where the Company rents its console medical devices on a month-to-month basis or for a longer specified period of time to customers. Government-sponsored research and development contracts and grants generally provide for payment on a cost-plus-fixed-fee basis. Revenues from these contracts and grants are recognized as work is performed, provided the government has appropriated sufficient funds for the work. Under contracts in which the Company elects to spend significantly more on the development project during the term of the contract than the total contract amount, the Company prospectively recognizes revenue on such contracts ratably over the term of the contract as related research and development costs are incurred.
Product Warranty	Product Warranty The Company generally provides a one-year warranty for certain products sold in which estimated contractual warranty obligations are recorded as an expense at the time of shipment. The Company’s products are subject to regulatory and quality standards. Future warranty costs are estimated based on historical product performance rates and related costs to repair given products. The accounting estimate related to product warranty expense involves judgment in determining future estimated warranty costs. Should actual performance rates or repair costs differ from estimates, revisions to the estimated warranty liability would be required.
Accumulated Other Comprehensive Income (Loss)	Accumulated Other Comprehensive Income (Loss) Comprehensive income (loss) is comprised of net income, plus all changes in equity of a business enterprise during a period from transactions and other events and circumstances from non-owner sources, including any foreign currency translation adjustments. These changes in equity are recorded as adjustments to accumulated other comprehensive income (loss) in the Company’s consolidated balance sheet. The components of accumulated other comprehensive income (loss) consist primarily of foreign currency translation adjustments. There were no reclassifications out of accumulated other comprehensive income (loss) during the fiscal years ended March 31, 2017, 2016 and 2015.
Translation of Foreign Currencies	Translation of Foreign Currencies The functional currency of the Company’s foreign subsidiaries is their local currency. The assets and liabilities of the Company’s foreign subsidiaries are translated into U.S. dollars at exchange rates in effect at the balance sheet date. Income and expense items are translated at the average exchange rates prevailing during the period. The cumulative translation effect for subsidiaries using a functional currency other than the U.S. dollar is included in accumulated other comprehensive income or loss as a separate component of stockholders’ equity. The Company’s intercompany accounts are denominated in the functional currency of the foreign subsidiary. Gains and losses resulting from the remeasurement of intercompany receivables that the Company considers to be of a long-term investment nature are recorded in accumulated other comprehensive income or loss as a separate component of stockholders’ equity, while gains and losses resulting from the remeasurement of intercompany receivables from those foreign subsidiaries for which the Company anticipates settlement in the foreseeable future are recorded in the consolidated statement of operations. The net foreign currency translation gains and losses recorded in the consolidated statements of operations for the fiscal years ended March 31, 2017, 2016 and 2015 were not significant.
Net Income Per Share	Net Income Per Share Basic net income per share is computed by dividing net income by the weighted average number of common shares outstanding during the fiscal year. Diluted net income per share is computed using the treasury stock method by dividing net income by the weighted average number of dilutive common shares outstanding during the fiscal year. Diluted shares outstanding is calculated by adding to the weighted average shares outstanding any potential dilutive securities outstanding for the fiscal year. Potential dilutive securities include stock options, restricted stock awards, restricted stock units, performance-based stock awards and shares to be purchased under the employee stock purchase plan. In fiscal years when a net loss is reported, all common stock equivalents are excluded from the calculation because they would have an anti-dilutive effect, meaning the loss per share would be reduced. Therefore, in periods when a loss is reported basic and dilutive loss per share are the same. Fiscal Years Ended March 31, 2017 2016 2015 Basic Net Income Per Share Net income $ 52,116 $ 38,147 $ 113,688 Weighted average shares used in computing basic net income per share 43,238 42,204 40,632 Net income per share - basic $ 1.21 $ 0.90 $ 2.80 Fiscal Years Ended March 31, 2017 2016 2015 Diluted Net Income Per Share Net income $ 52,116 $ 38,147 $ 113,688 Weighted average shares used in computing basic net income per share 43,238 42,204 40,632 Effect of dilutive securities 1,420 2,691 2,226 Weighted average shares used in computing diluted net income per share 44,658 44,895 42,858 Net income per share - diluted $ 1.17 $ 0.85 $ 2.65 For the fiscal years ended March 31, 2017, 2016 and 2015, approximately 24,000, 62,000 and 2,000 shares of common stock underlying outstanding securities primarily related to out-of-the-money stock options and performance-based awards where milestones were not met were not included in the computation of diluted earnings per share because their inclusion would be anti-dilutive.
Stock-Based Compensation	Stock-Based Compensation The Company’s stock-based compensation cost is measured at the grant date based on the fair value of the award and is recognized as an expense over the requisite service period, and includes an estimate of awards that will be forfeited. The fair value of stock option grants is estimated using the Black-Scholes option pricing model. Use of the valuation model requires management to make certain assumptions with respect to selected model inputs. The risk-free interest rate is based on the U.S. Treasury yield curve in effect at the time of grant for a term consistent with the expected life of the stock options. Volatility assumptions are calculated based on historical volatility of the Company’s stock. The Company estimates the expected term of options based on historical exercise experience and estimates of future exercises of unexercised options. In addition, an expected dividend yield of zero is used in the option valuation model because the Company does not pay cash dividends and does not expect to pay any cash dividends in the foreseeable future. Forfeitures are estimated based on an analysis of actual forfeitures, adjusted to the extent historical forfeitures may not be indicative of expected forfeitures in the future. For awards with service conditions only, the Company recognizes stock-based compensation expense on a straight-line basis over the requisite service period. For awards with service and performance conditions, the Company recognizes stock-based compensation expense using the graded vesting method over the requisite service period. Estimates of stock-based compensation expense for an award with performance conditions are based on the probable outcome of the performance conditions. The cumulative effect of changes in the probability outcomes are recorded in the period in which the changes occur. For awards with market-based conditions, the Company uses a Monte Carlo simulation model to estimate that the grant-date fair value. The fair value related to market-based awards is recorded as stock-based compensation expense over the vesting period regardless of whether the market condition is achieved or not.
Income Taxes	Income Taxes The Company’s provision for income taxes is comprised of a current and a deferred provision. The current income tax provision is calculated as the estimated taxes payable or refundable on income tax returns for the current fiscal year. The deferred income tax provision is calculated for the estimated future income tax effects attributable to temporary differences and carryforwards using expected tax rates in effect in the years during which the differences are expected to reverse. Deferred income taxes are recognized for the tax consequences in future years as the differences between the tax bases of assets and liabilities and their financial reporting amounts at each fiscal year end based on enacted tax laws and statutory tax rates applicable to the periods in which the differences are expected to impact taxable income. The Company regularly assesses its ability to realize its deferred tax assets. Assessing the realization of deferred tax assets requires significant management judgment. Valuation allowances are established when necessary to reduce net deferred tax assets to the amount that is more likely than not to be realized. The Company recognizes and measures uncertain tax positions using a two-step approach. The first step is to evaluate the tax position for recognition by determining if, based on the technical merits, it is more likely than not that the position will be sustained upon audit, including resolution of related appeals or litigation processes, if any. The second step is to measure the tax benefit at the largest amount that is more likely than not of being realized upon ultimate settlement. The Company reevaluates these uncertain tax positions on an ongoing basis, when applicable. This evaluation is based on factors including, but not limited to, changes in facts or circumstances, new information and technical insights, and changes in tax laws. Any changes in these factors could result in the recognition of a tax benefit or an additional charge to the tax provision. When applicable, the Company accrues for the effects of uncertain tax positions and the related potential penalties and interest through income tax expense.
Recent Accounting Pronouncements	Recent Accounting Pronouncements In March 2016, the FASB issued ASU 2016-09, Compensation-Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting In May 2014, the FASB issued ASU 2014-09, Revenue from Contracts with Customers In February 2016, the FASB issued ASU 2016-02, Leases

Summary of Significant Accoun23

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Mar. 31, 2017
Accounting Policies [Abstract]
Schedule of Earnings Per Share Basic And Diluted	Fiscal Years Ended March 31, 2017 2016 2015 Basic Net Income Per Share Net income $ 52,116 $ 38,147 $ 113,688 Weighted average shares used in computing basic net income per share 43,238 42,204 40,632 Net income per share - basic $ 1.21 $ 0.90 $ 2.80 Fiscal Years Ended March 31, 2017 2016 2015 Diluted Net Income Per Share Net income $ 52,116 $ 38,147 $ 113,688 Weighted average shares used in computing basic net income per share 43,238 42,204 40,632 Effect of dilutive securities 1,420 2,691 2,226 Weighted average shares used in computing diluted net income per share 44,658 44,895 42,858 Net income per share - diluted $ 1.17 $ 0.85 $ 2.65

Marketable Securities and Fai24

Marketable Securities and Fair Value Measurements (Tables)	12 Months Ended
	Mar. 31, 2017
Fair Value Disclosures [Abstract]
Marketable Securities by Balance Sheet Classification	The Company’s marketable securities at March 31, 2017 and 2016 are classified on the balance sheet as follows: March 31, 2017 March 31, 2016 (in $000's) Short-term marketable securities (within one year to maturity) $ 190,908 $ 163,822 Long-term marketable securities (one to two years to maturity) 47,143 1,000 $ 238,051 $ 164,822
Marketable Securities	The Company’s marketable securities at March 31, 2017 and 2016 are invested in the following: Amortized Gross Unrealized Gross Unrealized Fair Market Cost Gains Losses Value (in $000's) March 31, 2017: Short-term U.S. Treasury mutual fund securities $ 45,199 $ — $ (13 ) $ 45,186 Short-term government-backed securities 90,199 1 (87 ) 90,113 Short-term corporate debt securities 55,465 — (31 ) 55,434 Long-term U.S. Treasury mutual fund securities 1,998 — (3 ) 1,995 Long-term government-backed securities 43,484 5 (18 ) 43,471 Long-term corporate debt securities 1,853 — (1 ) 1,852 $ 238,198 $ 6 $ (153 ) $ 238,051 Amortized Gross Unrealized Gross Unrealized Fair Market Cost Gains Losses Value (in $000's) March 31, 2016: U.S. Treasury mutual fund securities $ 45,635 $ 21 $ — $ 45,656 Short-term government-backed securities 118,125 45 (4 ) 118,166 Long-term government-backed securities 999 1 — 1,000 $ 164,759 $ 67 $ (4 ) $ 164,822
Financial Instruments Measured at Fair Value	The following table presents the Company’s fair value hierarchy for its financial instruments measured at fair value as of March 31, 2017 and 2016: Level 1 Level 2 Level 3 Total March 31, 2017: (in $000's) Assets Short-term U.S. Treasury mutual fund securities $ — $ 45,186 $ — $ 45,186 Short-term government-backed securities — 90,113 — 90,113 Short-term corporate debt securities — 55,434 — 55,434 Long-term U.S. Treasury mutual fund securities — 1,995 — 1,995 Long-term government-backed securities — 43,471 — 43,471 Long-term corporate debt securities — 1,852 — 1,852 Liabilities Contingent consideration — — 9,153 9,153 Level 1 Level 2 Level 3 Total March 31, 2016: (in $000's) Assets U.S. Treasury mutual fund securities $ — $ 45,656 $ — $ 45,656 Short-term government-backed securities — 118,166 — 118,166 Long-term government-backed securities — 1,000 — 1,000 Liabilities Contingent consideration — — 7,563 7,563
Valuation Method Used to Calculate Level 3 Liabilities Measured at Estimated Fair Value of Contingent Consideration Related to Acquisition	This liability is reported as Level 3 as the estimated fair value of the contingent consideration related to the acquisition of the ECP requires significant management judgment or estimation and is calculated using the following valuation methods: Fair Value at Weighted Average March 31, 2017 Significant (range, if (in $000's) Valuation Methodology Unobservable Input applicable) Clinical and regulatory milestone $ 5,395 Probability weighted income approach Projected fiscal year of milestone payments 2019 to 2022 Discount rate 2.6% to 3.3% Probability of occurrence Probability adjusted level of 40% for the base case scenario and 5% to 20% for various upside and downside scenarios Revenue-based milestone 3,758 Monte Carlo simulation model Projected fiscal year of milestone payments 2023 to 2035 Discount rate 18% Expected volatility for forecasted revenues 50% $ 9,153
Change in Fair Value of Contingent Consideration as Determined by Level 3 Inputs	The following table summarizes the change in fair value, as determined by Level 3 inputs, of the contingent consideration for the fiscal years ended March 31, 2017, 2016 and 2015: Fiscal Years Ended March 31, 2017 2016 2015 (in $000's) Level 3 liabilities, beginning balance $ 7,563 $ 6,510 $ — Additions — — 6,000 Payments — — — Change in fair value 1,590 1,053 510 Level 3 liabilities, ending balance $ 9,153 $ 7,563 $ 6,510

Accounts Receivable (Tables)

Accounts Receivable (Tables)	12 Months Ended
	Mar. 31, 2017
Receivables [Abstract]
Components of Accounts Receivable	The components of accounts receivable are as follows: March 31, 2017 March 31, 2016 (in $000's) Trade receivables $ 54,337 $ 42,945 Allowance for doubtful accounts (282 ) (124 ) $ 54,055 $ 42,821
Summary of Allowance for Doubtful Accounts Receivable	The following table summarizes activity in the Company's allowance for doubtful accounts: Fiscal Years Ended March 31, 2017 2016 2015 (in $000's) Balance at beginning of year $ 124 $ 177 $ 185 Additions 159 42 115 Write-offs (1 ) (95 ) (123 ) Balance at end of year $ 282 $ 124 $ 177

Inventories (Tables)

Inventories (Tables)	12 Months Ended
	Mar. 31, 2017
Inventory Disclosure [Abstract]
Components of Inventories	The components of inventories are as follows: March 31, 2017 March 31, 2016 (in $000's) Raw materials and supplies $ 9,784 $ 7,993 Work-in-progress 16,504 13,147 Finished goods 8,643 5,600 $ 34,931 $ 26,740

Property and Equipment (Tables)

Property and Equipment (Tables)	12 Months Ended
	Mar. 31, 2017
Property Plant And Equipment [Abstract]
Components of Property and Equipment	The components of property and equipment are as follows: March 31, 2017 March 31, 2016 (in $000's) Land $ 4,046 $ - Building and building improvements 10,900 - Capital lease asset 16,784 - Leasehold improvements 34,854 11,833 Machinery and equipment 27,989 25,211 Furniture and fixtures 3,899 1,510 Construction in progress 9,257 3,712 Total cost 107,729 42,266 Less accumulated depreciation (19,952 ) (19,082 ) $ 87,777 $ 23,184

Goodwill and In-Process Resea28

Goodwill and In-Process Research and Development (Tables)	12 Months Ended
	Mar. 31, 2017
Goodwill And Intangible Assets Disclosure [Abstract]
Goodwill Activity	The goodwill activity is as follows: (in $000's) Balance at March 31, 2015 $ 31,534 Foreign currency translation impact 1,469 Balance at March 31, 2016 $ 33,003 Foreign currency translation impact (1,958 ) Balance at March 31, 2017 $ 31,045
Carrying value of In-Process Research and Development	The carrying value of the Company’s IPR&D assets and the change in the balance for the fiscal years ended March 31, 2017 and 2016 is as follows: (in $000's) Balance at March 31, 2015 $ 14,711 Foreign currency translation impact 685 Balance at March 31, 2016 $ 15,396 Foreign currency translation impact (914 ) Balance at March 31, 2017 $ 14,482

Stock Award Plans and Stock-B29

Stock Award Plans and Stock-Based Compensation (Tables)	12 Months Ended
	Mar. 31, 2017
Stock-Based Compensation Recognized	The following table summarizes stock-based compensation expense by financial statement line item in the Company’s consolidated statements of operations for the fiscal years ended March 31, 2017, 2016 and 2015: Fiscal Years Ended March 31, 2017 2016 2015 (in $000's) Cost of product revenue $ 1,061 $ 895 $ 665 Research and development 6,050 3,950 3,205 Selling, general and administrative 25,755 24,208 12,650 $ 32,866 $ 29,053 $ 16,520
Components of Stock-Based Compensation	The components of stock-based compensation for the fiscal years ended March 31, 2017, 2016 and 2015 were as follows: Fiscal Years Ended March 31, 2017 2016 2015 (in $000's) Restricted stock units $ 26,570 $ 23,708 $ 13,539 Stock options 5,829 4,866 2,708 Employee stock purchase plan 467 479 273 $ 32,866 $ 29,053 $ 16,520
Summary of Stock Option Activity	The following table summarized stock option activity for the year ended March 31, 2017: Weighted Weighted Average Aggregate Average Remaining Intrinsic Options Exercise Contractual Value (in thousands) Price Term (years) (in thousands) Outstanding at beginning of period 2,244 $ 20.55 5.19 Granted 180 106.10 Exercised (755 ) 14.12 Cancelled and expired (23 ) 73.50 Outstanding at end of period 1,646 $ 32.09 5.46 $ 153,254 Exercisable at end of period 1,156 $ 18.26 4.36 $ 123,592 Options vested and expected to vest at end of period 1,594 $ 31.06 5.37 $ 150,056
Summary of Weighted Average Grant-Date Fair Values And Weighted Average Assumptions Used to Calculate Fair Value of Options Granted	The weighted average grant-date fair values and weighted average assumptions used in the calculation of fair value of options granted during the fiscal years ended March 31, 2017, 2016 and 2015 was as follows: Fiscal Years Ended March 31, 2017 2016 2015 Valuation assumptions: Weighted average grant-date fair value $ 42.40 $ 29.57 $ 9.29 Risk-free interest rate 1.41 % 1.55 % 1.60 % Expected option life (years) 4.14 4.15 4.19 Expected volatility 48.9 % 49.7 % 49.3 %
Restricted Stock Units
Summary of Restricted Stock Units Activity	The following table summarizes restricted stock unit activity for the fiscal year ended March 31, 2017: Number of Shares Weighted Average Grant Date Fair Value (in thousands) (per share) Restricted stock units at beginning of period 1,263 $ 57.95 Granted 366 $ 97.43 Vested (502 ) $ 35.05 Forfeited (71 ) $ 91.39 Restricted stock units at end of period 1,056 $ 80.50
Monte Carlo Simulation Model to Estimate Grant-Date Fair Value of Restricted Stock Units	The table below sets forth the assumptions used to value the market-based awards and the estimated grant-date fair value: June 2015 Awards November 2016 Awards Risk-free interest rate 1.10 % 0.90 % Dividend yield 0 % 0 % Remaining performance period (years) 1.21 1.21 Expected volatility 47.2 % 50.6 % Estimated grant date fair value (per share) $ 107.10 $ 62.55 Target performance (number of shares) 107,660 41,526

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Mar. 31, 2017
Income Tax Disclosure [Abstract]
Income before Income Taxes	The components of the Company’s income tax provision (benefit) for the fiscal years ended March 31, 2017, 2016 and 2015 are as follows: 2017 2016 2015 (in $000's) Income before provision for income taxes: United States $ 78,172 $ 54,406 $ 22,243 Foreign 13,170 11,432 6,522 Income before income taxes $ 91,342 $ 65,838 $ 28,765 Current tax expense: Federal $ 7,313 $ 1,690 $ 464 State 5,045 2,113 424 Foreign 1,066 1,592 1,283 13,424 5,395 2,171 Deferred tax expense (benefit): Federal 23,008 18,769 (66,140 ) State (349 ) 1,284 (13,430 ) Foreign 3,144 2,243 (7,524 ) 25,803 22,296 (87,094 ) Total income tax provision (benefit) $ 39,227 $ 27,691 $ (84,923 )
Components of Income Tax Provision (Benefit)	The components of the Company’s income tax provision (benefit) for the fiscal years ended March 31, 2017, 2016 and 2015 are as follows: 2017 2016 2015 (in $000's) Income before provision for income taxes: United States $ 78,172 $ 54,406 $ 22,243 Foreign 13,170 11,432 6,522 Income before income taxes $ 91,342 $ 65,838 $ 28,765 Current tax expense: Federal $ 7,313 $ 1,690 $ 464 State 5,045 2,113 424 Foreign 1,066 1,592 1,283 13,424 5,395 2,171 Deferred tax expense (benefit): Federal 23,008 18,769 (66,140 ) State (349 ) 1,284 (13,430 ) Foreign 3,144 2,243 (7,524 ) 25,803 22,296 (87,094 ) Total income tax provision (benefit) $ 39,227 $ 27,691 $ (84,923 )
Components of Net Deferred Taxes	The components of the Company’s net deferred taxes were as follows: March 31, 2017 2016 (in $000's) Deferred tax assets NOL carryforwards and tax credit carryforwards $ 8,814 $ 34,305 Stock-based compensation 16,560 14,879 Nondeductible reserves and accruals 10,303 8,550 Amortizable intangibles other than goodwill 1,846 2,420 Capitalized research and development — 442 Foreign NOL carryforwards 13,634 17,635 Deferred revenue 4,308 3,351 Depreciation 289 353 Other, net 1,308 1,802 57,062 83,737 Deferred tax liabilities Indefinite lived intangibles (9,444 ) (8,480 ) In-process research and development (4,374 ) (4,649 ) Domestic deferred tax liability on foreign NOL carryforwards (6,836 ) (10,488 ) (20,654 ) (23,617 ) Net deferred tax assets 36,408 60,120 Valuation allowance (2,468 ) (2,418 ) Net deferred tax assets $ 33,940 $ 57,702 Reported as: Long-term deferred tax assets, net $ 34,723 $ 58,534 Long-term deferred tax liabilities (783 ) (832 ) Net deferred tax assets $ 33,940 $ 57,702
Differences Between Federal Statutory Income Tax Rate and Effective Tax Rates	A reconciliation of the federal statutory income tax rate to the Company’s effective income tax rate is as follows for the fiscal years ended March 31, 2017, 2016, and 2015: 2017 2016 2015 Statutory income tax rate 35.0 % 35.0 % 35.0 % Increase (decrease) resulting from: Change in valuation allowance 0.2 0.7 (342.8 ) Credits (3.3 ) (4.1 ) (1.9 ) Foreign taxes 2.0 2.5 4.5 State taxes, net 3.8 3.7 4.0 Permanent differences 3.3 3.0 3.9 Stock based compensation 0.2 0.3 0.3 Rate differential on foreign operations 0.1 - 0.2 Other 1.7 1.0 1.6 Effective tax rate 43.0 % 42.1 % (295.2 ) %
Changes in Valuation Allowance for Deferred Tax Assets	Changes in the valuation allowance for deferred tax assets during the fiscal years ended March 31, 2017, 2016 and 2015 were as follows: 2017 2016 2015 (in $000's) Valuation allowance as of beginning of year $ 2,418 $ 2,912 $ 102,093 Decreases recorded as benefit to income tax provision - (1,171 ) (101,468 ) Increases due to foreign net operating loss in certain foreign jurisdictions 50 677 2,287 Valuation allowance as of end of year $ 2,468 $ 2,418 $ 2,912

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
	Mar. 31, 2017
Commitments And Contingencies Disclosure [Abstract]
Future Minimum Lease Payments Under Non-Cancelable Leases	Future minimum lease payments under non-cancelable leases as of March 31, 2017 are approximately as follows: Fiscal Years Ending March 31, Capital Lease Operating Leases (in $000s) 2018 $ 1,311 $ 1,670 2019 1,349 1,593 2020 1,349 1,532 2021 1,373 1,542 2022 1,390 1,084 Thereafter 13,746 752 Total minimum lease payments 20,518 $ 8,173 Less amounts representing interest (4,180 ) Total capital lease obligation $ 16,338 Less current capital lease obligation (799 ) Capital lease obligation, net of current portion $ 15,539

Accrued Expenses (Tables)

Accrued Expenses (Tables)	12 Months Ended
	Mar. 31, 2017
Payables And Accruals [Abstract]
Accrued Expenses	Accrued expenses consisted of the following: March 31, 2017 March 31, 2016 (in $000's) Employee compensation $ 23,290 $ 18,359 Sales and income taxes 3,180 2,527 Research and development 2,349 1,587 Accrued capital expenditures 2,300 - Professional, legal and accounting fees 2,019 1,764 Marketing 1,827 1,146 Warranty 717 998 Other 2,021 2,001 $ 37,703 $ 28,382

Quarterly Results of Operation

Quarterly Results of Operation (Tables)	12 Months Ended
	Mar. 31, 2017
Quarterly Financial Information Disclosure [Abstract]
Summary of Unaudited Quarterly Results of Operations	The following is a summary of the Company’s unaudited quarterly results of operations for the fiscal years ending March 31, 2017 and 2016: Fiscal Year Ended March 31, 2017 1st Quarter 2nd Quarter 3rd Quarter 4th Quarter Total Year (in $000's) Total revenues $ 102,995 $ 102,955 $ 114,674 $ 124,680 $ 445,304 Cost of product revenue 15,070 17,309 18,987 19,261 70,627 Other operating expenses 66,692 71,138 70,284 76,425 284,539 Other income, net 192 228 423 362 1,205 Income before income taxes 21,425 14,736 25,826 29,356 91,343 Income tax provision 8,515 5,861 10,394 14,457 39,227 Net income $ 12,910 $ 8,875 $ 15,432 $ 14,899 $ 52,116 Basic net income per share $ 0.30 $ 0.21 $ 0.36 $ 0.34 $ 1.21 Diluted net income per share $ 0.29 $ 0.20 $ 0.34 $ 0.33 $ 1.17 Fiscal Year Ended March 31, 2016 1st Quarter 2nd Quarter 3rd Quarter 4th Quarter Total Year (in $000's) Total revenues $ 73,432 $ 76,359 $ 85,795 $ 93,957 $ 329,543 Cost of product revenue 10,868 12,144 12,744 14,663 50,419 Other operating expenses 47,533 51,398 55,608 59,481 214,020 Other income, net 116 149 55 414 734 Income before income taxes 15,147 12,966 17,498 20,227 65,838 Income tax provision 6,288 5,231 6,943 9,229 27,691 Net income $ 8,859 $ 7,735 $ 10,555 $ 10,998 $ 38,147 Basic net income per share $ 0.21 $ 0.18 $ 0.25 $ 0.26 $ 0.90 Diluted net income per share $ 0.20 $ 0.17 $ 0.23 $ 0.24 $ 0.85

Summary of Significant Accoun34

Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($)	12 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2015
Summary Of Significant Accounting Policy [Line Items]
Product warranty period	1 year
Reclassifications out of accumulated other comprehensive income (loss)	$ 0	$ 0	$ 0
Expected dividend yield	0.00%
Stock Options and Performance Shares
Summary Of Significant Accounting Policy [Line Items]
Shares excluded from the calculation of diluted weighted average shares outstanding	24,000	62,000	2,000
Leasehold Improvements
Summary Of Significant Accounting Policy [Line Items]
Leasehold improvements, useful life	shorter of the lease term or the estimated useful lives
Minimum | Machinery and Equipment
Summary Of Significant Accounting Policy [Line Items]
Property and Equipment, useful life	3 years
Minimum | Computer Software
Summary Of Significant Accounting Policy [Line Items]
Property and Equipment, useful life	3 years
Minimum | Furniture and Fixtures
Summary Of Significant Accounting Policy [Line Items]
Property and Equipment, useful life	3 years
Minimum | Building and Building Improvements
Summary Of Significant Accounting Policy [Line Items]
Property and Equipment, useful life	7 years
Maximum | Machinery and Equipment
Summary Of Significant Accounting Policy [Line Items]
Property and Equipment, useful life	5 years
Maximum | Computer Software
Summary Of Significant Accounting Policy [Line Items]
Property and Equipment, useful life	5 years
Maximum | Furniture and Fixtures
Summary Of Significant Accounting Policy [Line Items]
Property and Equipment, useful life	5 years
Maximum | Building and Building Improvements
Summary Of Significant Accounting Policy [Line Items]
Property and Equipment, useful life	33 years

Computation of Basic and Dilute

Computation of Basic and Diluted Net Income Per Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2015
Basic Net Income Per Share
Net income	$ 14,899	$ 15,432	$ 8,875	$ 12,910	$ 10,998	$ 10,555	$ 7,735	$ 8,859	$ 52,116	$ 38,147	$ 113,688
Weighted average shares used in computing basic net income per share									43,238	42,204	40,632
Net income per share - basic	$ 0.34	$ 0.36	$ 0.21	$ 0.30	$ 0.26	$ 0.25	$ 0.18	$ 0.21	$ 1.21	$ 0.90	$ 2.80
Diluted Net Income Per Share
Net income	$ 14,899	$ 15,432	$ 8,875	$ 12,910	$ 10,998	$ 10,555	$ 7,735	$ 8,859	$ 52,116	$ 38,147	$ 113,688
Weighted average shares used in computing basic net income per share									43,238	42,204	40,632
Effect of dilutive securities									1,420	2,691	2,226
Weighted average shares used in computing diluted net income per share									44,658	44,895	42,858
Net income per share - diluted	$ 0.33	$ 0.34	$ 0.20	$ 0.29	$ 0.24	$ 0.23	$ 0.17	$ 0.20	$ 1.17	$ 0.85	$ 2.65

Marketable Securities (Detail)

Marketable Securities (Detail) - USD ($) $ in Thousands	Mar. 31, 2017	Mar. 31, 2016
Fair Value Disclosures [Abstract]
Short-term marketable securities (within one year to maturity)	$ 190,908	$ 163,822
Long-term marketable securities (one to two years to maturity)	47,143	1,000
Available-for-sale securities, fair value disclosure	$ 238,051	$ 164,822

Marketable Securities (Parenthe

Marketable Securities (Parenthetical) (Detail)	12 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Maximum
Investment [Line Items]
Short-term marketable securities, maturity period	1 year	1 year
Long-term marketable securities, maturity period	2 years	2 years
Minimum
Investment [Line Items]
Long-term marketable securities, maturity period	1 year	1 year

Investable Marketable Securitie

Investable Marketable Securities (Detail) - USD ($) $ in Thousands	Mar. 31, 2017	Mar. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Amortized Cost	$ 238,198	$ 164,759
Gross Unrealized Gains	6	67
Gross Unrealized Losses	(153)	(4)
Fair Market Value	238,051	164,822
US Treasury mutual fund Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Amortized Cost		45,635
Gross Unrealized Gains		21
Fair Market Value		45,656
US Treasury mutual fund Securities | Short-term Investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Amortized Cost	45,199
Gross Unrealized Losses	(13)
Fair Market Value	45,186
US Treasury mutual fund Securities | Long-term Investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Amortized Cost	1,998
Gross Unrealized Losses	(3)
Fair Market Value	1,995
US Government-sponsored Enterprises Debt Securities | Short-term Investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Amortized Cost	90,199	118,125
Gross Unrealized Gains	1	45
Gross Unrealized Losses	(87)	(4)
Fair Market Value	90,113	118,166
US Government-sponsored Enterprises Debt Securities | Long-term Investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Amortized Cost	43,484	999
Gross Unrealized Gains	5	1
Gross Unrealized Losses	(18)
Fair Market Value	43,471	$ 1,000
Corporate Debt Securities | Short-term Investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Amortized Cost	55,465
Gross Unrealized Losses	(31)
Fair Market Value	55,434
Corporate Debt Securities | Long-term Investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Amortized Cost	1,853
Gross Unrealized Losses	(1)
Fair Market Value	$ 1,852

Financial Instruments Measured

Financial Instruments Measured at Fair Value (Detail) - USD ($) $ in Thousands	Mar. 31, 2017	Mar. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities, fair value disclosure	$ 238,051	$ 164,822
Contingent consideration	9,153	7,563
Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Contingent consideration	9,153	7,563
US Treasury mutual fund Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities, fair value disclosure		45,656
US Treasury mutual fund Securities | Short-term Investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities, fair value disclosure	45,186
US Treasury mutual fund Securities | Long-term Investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities, fair value disclosure	1,995
US Treasury mutual fund Securities | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities, fair value disclosure		45,656
US Treasury mutual fund Securities | Level 2 | Short-term Investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities, fair value disclosure	45,186
US Treasury mutual fund Securities | Level 2 | Long-term Investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities, fair value disclosure	1,995
US Government-sponsored Enterprises Debt Securities | Short-term Investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities, fair value disclosure	90,113	118,166
US Government-sponsored Enterprises Debt Securities | Long-term Investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities, fair value disclosure	43,471	1,000
US Government-sponsored Enterprises Debt Securities | Level 2 | Short-term Investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities, fair value disclosure	90,113	118,166
US Government-sponsored Enterprises Debt Securities | Level 2 | Long-term Investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities, fair value disclosure	43,471	$ 1,000
Corporate Debt Securities | Short-term Investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities, fair value disclosure	55,434
Corporate Debt Securities | Long-term Investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities, fair value disclosure	1,852
Corporate Debt Securities | Level 2 | Short-term Investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities, fair value disclosure	55,434
Corporate Debt Securities | Level 2 | Long-term Investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities, fair value disclosure	$ 1,852

Marketable Securities and Fai40

Marketable Securities and Fair Value Measurements - Additional Information (Detail) - USD ($) $ in Millions	1 Months Ended
	Jul. 31, 2014	Mar. 31, 2017	Mar. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Aggregate carrying amount of portfolio of other investments		$ 7.2	$ 4.4
ECP Entwicklungsgesellschaft mbH
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Payments to acquire businesses, cash paid	$ 13
Potential payouts payments	$ 15

Valuation Method Used to Calcul

Valuation Method Used to Calculate Level 3 Liabilities Measured at Estimated Fair Value of Contingent Consideration Related to Acquisition (Detail) - USD ($) $ in Thousands	Jul. 01, 2014	Mar. 31, 2017	Mar. 31, 2016
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Contingent consideration		$ 9,153	$ 7,563
ECP Entwicklungsgesellschaft mbH
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Discount rate	21.50%
Level 3
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Contingent consideration		9,153	$ 7,563
Level 3 | ECP Entwicklungsgesellschaft mbH
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Contingent consideration		9,153
Level 3 | ECP Entwicklungsgesellschaft mbH | Probability weighted income approach | Clinical and regulatory milestone
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Contingent consideration		$ 5,395
Level 3 | ECP Entwicklungsgesellschaft mbH | Probability weighted income approach | Clinical and regulatory milestone | Base Case Scenario | Contingent Consideration
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Probability of occurrence		40.00%
Level 3 | ECP Entwicklungsgesellschaft mbH | Probability weighted income approach | Clinical and regulatory milestone | Minimum | Contingent Consideration
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Projected fiscal year of milestone payments		2,019
Discount rate		2.60%
Level 3 | ECP Entwicklungsgesellschaft mbH | Probability weighted income approach | Clinical and regulatory milestone | Minimum | Various Upside and Downside Scenarios | Contingent Consideration
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Probability of occurrence		5.00%
Level 3 | ECP Entwicklungsgesellschaft mbH | Probability weighted income approach | Clinical and regulatory milestone | Maximum | Contingent Consideration
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Projected fiscal year of milestone payments		2,022
Discount rate		3.30%
Level 3 | ECP Entwicklungsgesellschaft mbH | Probability weighted income approach | Clinical and regulatory milestone | Maximum | Various Upside and Downside Scenarios | Contingent Consideration
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Probability of occurrence		20.00%
Level 3 | ECP Entwicklungsgesellschaft mbH | Monte Carlo simulation model | Revenue-based milestone
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Contingent consideration		$ 3,758
Level 3 | ECP Entwicklungsgesellschaft mbH | Monte Carlo simulation model | Revenue-based milestone | Contingent Consideration
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Discount rate		18.00%
Expected volatility for forecasted revenues		50.00%
Level 3 | ECP Entwicklungsgesellschaft mbH | Monte Carlo simulation model | Revenue-based milestone | Minimum | Contingent Consideration
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Projected fiscal year of milestone payments		2,023
Level 3 | ECP Entwicklungsgesellschaft mbH | Monte Carlo simulation model | Revenue-based milestone | Maximum | Contingent Consideration
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Projected fiscal year of milestone payments		2,035

Change in Fair Value of Conting

Change in Fair Value of Contingent Consideration as Determined by Level 3 Inputs (Detail) - Contingent Consideration - ECP Entwicklungsgesellschaft mbH - Level 3 - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2015
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Level 3 liabilities, beginning balance	$ 7,563	$ 6,510	$ 0
Additions	0	0	6,000
Payments	0	0	0
Change in fair value	1,590	1,053	510
Level 3 liabilities, ending balance	$ 9,153	$ 7,563	$ 6,510

Components of Accounts Receivab

Components of Accounts Receivable (Detail) - USD ($) $ in Thousands	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2014
Receivables [Abstract]
Trade receivables	$ 54,337	$ 42,945
Allowance for doubtful accounts	(282)	(124)	$ (177)	$ (185)
Accounts receivable, net	$ 54,055	$ 42,821

Summary of Allowance for Doubtf

Summary of Allowance for Doubtful Accounts Receivable (Detail) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2015
Receivables [Abstract]
Balance at Beginning of Period	$ 124	$ 177	$ 185
Additions	159	42	115
Write-offs	(1)	(95)	(123)
Balance at End of Period	$ 282	$ 124	$ 177

Components of Inventories (Deta

Components of Inventories (Detail) - USD ($) $ in Thousands	Mar. 31, 2017	Mar. 31, 2016
Inventory Disclosure [Abstract]
Raw materials and supplies	$ 9,784	$ 7,993
Work-in-progress	16,504	13,147
Finished goods	8,643	5,600
Inventories	$ 34,931	$ 26,740

Components of Property and Equi

Components of Property and Equipment (Detail) - USD ($) $ in Thousands	Mar. 31, 2017	Mar. 31, 2016
Property Plant And Equipment [Abstract]
Land	$ 4,046
Building and building improvements	10,900
Capital lease asset	16,784
Leasehold improvements	34,854	$ 11,833
Machinery and equipment	27,989	25,211
Furniture and fixtures	3,899	1,510
Construction in progress	9,257	3,712
Total cost	107,729	42,266
Less accumulated depreciation	(19,952)	(19,082)
Property and equipment, net	$ 87,777	$ 23,184

Property and Equipment - Additi

Property and Equipment - Additional Information (Detail) $ in Thousands	1 Months Ended		12 Months Ended
	Feb. 28, 2017USD ($)	Aug. 31, 2016USD ($)	Mar. 31, 2017USD ($)	Mar. 31, 2016USD ($)	Mar. 31, 2015USD ($)	Dec. 31, 2016ft²
Property Plant And Equipment [Line Items]
Property and equipment			$ 107,729	$ 42,266
Acquisition cost for property and equipment			50,415	15,624	$ 5,188
Depreciation expense			$ 6,200	$ 3,300	$ 2,700
Europe
Property Plant And Equipment [Line Items]
Acquisition cost for property and equipment	$ 12,600
Lease Agreements | Europe
Property Plant And Equipment [Line Items]
Office space under lease | ft²						33,000
Capital lease assets
Property Plant And Equipment [Line Items]
Property and equipment		$ 16,800
Capital lease asset, useful life		15 years
Land | Europe
Property Plant And Equipment [Line Items]
Acquisition cost for property and equipment	4,000
Building and Building Improvements | Europe
Property Plant And Equipment [Line Items]
Acquisition cost for property and equipment	$ 8,600

Goodwill and In-Process Resea48

Goodwill and In-Process Research and Development - Additional Information (Detail) - USD ($)	Jul. 01, 2014	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2015	Jul. 31, 2014
Goodwill [Line Items]
Goodwill		$ 31,045,000	$ 33,003,000	$ 31,534,000
Accumulated impairment loss, goodwill		0
In-process research and development		$ 14,482,000	$ 15,396,000	$ 14,711,000
ECP Entwicklungsgesellschaft mbH
Goodwill [Line Items]
In-process research and development					$ 18,500,000
Fair value inputs, discount rate	21.50%

Goodwill Activity (Detail)

Goodwill Activity (Detail) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Goodwill And Intangible Assets Disclosure [Abstract]
Beginning balance	$ 33,003	$ 31,534
Foreign currency translation impact	(1,958)	1,469
Ending balance	$ 31,045	$ 33,003

Carrying value of In-Process Re

Carrying value of In-Process Research and Development (Detail) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Goodwill And Intangible Assets Disclosure [Abstract]
Beginning balance	$ 15,396	$ 14,711
Foreign currency translation impact	(914)	685
Ending balance	$ 14,482	$ 15,396

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Detail) - $ / shares	Mar. 31, 2017	Mar. 31, 2016
Stockholders Equity Note [Abstract]
Class B Preferred Stock, par value	$ 0.01	$ 0.01
Class B Preferred Stock, Authorized	1,000,000	1,000,000
Class B Preferred Stock, Issued	0	0
Class B Preferred Stock, outstanding	0	0

Stock Award Plans and Stock-B52

Stock Award Plans and Stock-Based Compensation - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended						12 Months Ended
	Nov. 30, 2016	May 31, 2016	Jun. 30, 2015	May 31, 2015	May 31, 2014	Jun. 30, 2011	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Aggregate intrinsic value of options exercised in period							$ 74,800	$ 58,600	$ 20,000
Proceeds from the exercise of stock options							10,660	9,771	10,927
Fair value of options vested in period							$ 4,000	2,600	2,600
Expected dividend yield							0.00%
Stock-based compensation							$ 32,866	29,053	16,520
Two Thousand Fifteen Stock Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock option conversion description							Each share of stock issued pursuant to a stock option or stock appreciation right counts as one share against the maximum number of shares issuable under the 2015 Plan, while each share of stock issued pursuant to any other type of award counts as 1.8 shares against the maximum number of shares issuable under the 2015 Plan.
Shares available for future issuance under the Plan							3,118,000
Two Thousand Eight Stock Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for future issuance under the Plan							159,000
Description of share counts for awards other than 2008 Stock Incentive Plan							Each share of stock currently issued pursuant to any other type of award counts as 1.58 shares against the maximum number of shares issuable under the 2008 Plan
Employee Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock award plans, outstanding stock options expiration period							10 years
Unrecognized stock-based compensation expense							$ 7,700
Unrecognized stock-based compensation expense, weighted-average recognition period							2 years 6 months
Expected dividend yield							0.00%
Stock-based compensation							$ 5,829	$ 4,866	$ 2,708
Restricted Stock and Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized stock-based compensation expense							$ 27,400
Unrecognized stock-based compensation expense, weighted-average recognition period							2 years
Weighted average grant-date fair value for restricted stock and restricted stock units granted							$ 97.43	$ 87.45	$ 22.07
Fair value of restricted stock and restricted stock units vested in period							$ 51,300	$ 39,600	$ 11,200
Performance and Market-Based Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized stock-based compensation expense							$ 15,500
Unrecognized stock-based compensation expense, weighted-average recognition period							2 years 1 month 6 days
Performance Based Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted share unit issued				183,940	379,752	100,000
Non-vested shares, outstanding							74,000
Shares of award granted, upon achievement of service milestone							100,000
Performance Based Restricted Stock Units | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted share unit issued		190,890
Performance Based Restricted Stock Units Issued in May 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Non-vested shares, outstanding							132,000
Performance Based Restricted Stock Units Issued in May 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Non-vested shares, outstanding							120,000
Market Based Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based payment award vesting term							2018-06
Share based compensation arrangement performance period							3 years
Equity award, vesting options							One-half of the market-based restricted stock units earned will vest in June 2018 and the remaining restricted stock units will vest one year thereafter provided the executive officers are still employed with the Company.
Market Based Restricted Stock Units | Chief Financial Officer
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted share unit issued			322,980
Non-vested shares, outstanding			281,530
Market Based Restricted Stock Units | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted Share earning							300.00%
Market Based Restricted Stock Units | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted Share earning							0.00%
Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected dividend yield	0.00%		0.00%
Weighted average grant-date fair value for restricted stock and restricted stock units granted							$ 97.43
Restricted share unit issued							366,000
Non-vested shares, outstanding							1,056,000	1,263,000
Share based payment award vesting term							2018-06
Share based compensation arrangement performance period							3 years
Equity award, vesting options							One-half of the restricted stock units will potentially vest in June 2018 based on performance criteria described above and the remaining half of the restricted stock units will vest one year thereafter.
Stock-based compensation							$ 26,570	$ 23,708	13,539
Restricted Stock Units | Executive Office
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted share unit issued	41,526
Restricted Stock Units | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted Share earning							100.00%
Restricted Stock Units | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted Share earning							0.00%
Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
ESPP, exercise price as a percentage of its market price							85.00%
Stock-based compensation							$ 500	$ 500	$ 300

Stock-Based Compensation Recogn

Stock-Based Compensation Recognized (Detail) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2015
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation	$ 32,866	$ 29,053	$ 16,520
Cost of product revenue
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation	1,061	895	665
Research and development
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation	6,050	3,950	3,205
Selling, general and administrative
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation	$ 25,755	$ 24,208	$ 12,650

Components of Stock-Based Compe

Components of Stock-Based Compensation (Detail) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2015
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation	$ 32,866	$ 29,053	$ 16,520
Restricted Stock Units
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation	26,570	23,708	13,539
Stock Options
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation	5,829	4,866	2,708
Employee Stock Purchase Plan
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation	$ 467	$ 479	$ 273

Summary of Stock Option Activit

Summary of Stock Option Activity (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Options
Outstanding at beginning of period	2,244
Granted	180
Exercised	(755)
Cancelled and expired	(23)
Outstanding at end of period	1,646	2,244
Exercisable at end of period	1,156
Options vested and expected to vest at end of period	1,594
Weighted-Average Exercise Price
Outstanding at beginning of period	$ 20.55
Granted	106.10
Exercised	14.12
Cancelled and expired	73.50
Outstanding at end of period	32.09	$ 20.55
Exercisable at end of period	18.26
Options vested and expected to vest at end of period	$ 31.06
Weighted-Average Remaining Contractual Term (years)
Outstanding	5 years 5 months 16 days	5 years 2 months 9 days
Exercisable at end of period	4 years 4 months 10 days
Options vested and expected to vest at end of period	5 years 4 months 13 days
Aggregate Intrinsic Value
Outstanding at end of period	$ 153,254
Exercisable at end of period	123,592
Options vested and expected to vest at end of period	$ 150,056

Summary of Weighted Average Gra

Summary of Weighted Average Grant-Date Fair Values And Weighted Average Assumptions Used to Calculate Fair Value of Options Granted (Detail) - Stock Options - $ / shares	12 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2015
Valuation assumptions:
Weighted average grant-date fair value	$ 42.40	$ 29.57	$ 9.29
Risk-free interest rate	1.41%	1.55%	1.60%
Expected option life (years)	4 years 1 month 21 days	4 years 1 month 24 days	4 years 2 months 9 days
Expected volatility	48.90%	49.70%	49.30%

Summary of Restricted Stock Uni

Summary of Restricted Stock Units Activity (Detail) - Restricted Stock Units shares in Thousands	12 Months Ended
	Mar. 31, 2017$ / sharesshares
Number of Shares
Beginning Balance | shares	1,263
Granted | shares	366
Vested | shares	(502)
Forfeited | shares	(71)
Ending Balance | shares	1,056
Weighted Average Grant Date Fair Value
Beginning Balance | $ / shares	$ 57.95
Granted | $ / shares	97.43
Vested | $ / shares	35.05
Forfeited | $ / shares	91.39
Ending Balance | $ / shares	$ 80.50

Monte Carlo Simulation Model to

Monte Carlo Simulation Model to Estimate Grant-Date Fair Value of Restricted Stock Units (Detail) - $ / shares	1 Months Ended		12 Months Ended
	Nov. 30, 2016	Jun. 30, 2015	Mar. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Dividend yield			0.00%
Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rate	0.90%	1.10%
Dividend yield	0.00%	0.00%
Remaining performance period (years)	1 year 2 months 16 days	1 year 2 months 16 days
Expected volatility	50.60%	47.20%
Estimated grant date fair value (per share)	$ 62.55	$ 107.10
Target performance (number of shares)	41,526	107,660

Components of Income Tax Provis

Components of Income Tax Provision (Benefit) (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2015
Income Tax Disclosure [Abstract]
Income (loss) before income taxes									$ 78,172	$ 54,406	$ 22,243
Income (loss) before income taxes, foreign									13,170	11,432	6,522
Income (loss) before income taxes									91,342	65,838	28,765
Current income tax provision, Federal									7,313	1,690	464
Current income tax provision, State									5,045	2,113	424
Current income tax provision, Foreign									1,066	1,592	1,283
Current income tax provision									13,424	5,395	2,171
Deferred income tax provision, Federal									23,008	18,769	(66,140)
Deferred income tax provision, State									(349)	1,284	(13,430)
Deferred income tax provision, Foreign									3,144	2,243	(7,524)
Deferred income tax provision									25,803	22,296	(87,094)
Total income tax provision (benefit)	$ 14,457	$ 10,394	$ 5,861	$ 8,515	$ 9,229	$ 6,943	$ 5,231	$ 6,288	$ 39,227	$ 27,691	$ (84,923)

Components of Net Deferred Taxe

Components of Net Deferred Taxes (Detail) - USD ($) $ in Thousands	Mar. 31, 2017	Mar. 31, 2016
Deferred tax assets
NOL carryforwards and tax credit carryforwards	$ 8,814	$ 34,305
Stock-based compensation	16,560	14,879
Nondeductible reserves and accruals	10,303	8,550
Amortizable intangibles other than goodwill	1,846	2,420
Capitalized research and development		442
Foreign NOL carryforwards	13,634	17,635
Deferred revenue	4,308	3,351
Depreciation	289	353
Other, net	1,308	1,802
Deferred Tax Assets, Gross, Total	57,062	83,737
Deferred tax liabilities
Indefinite lived intangibles	(9,444)	(8,480)
In-process research and development	(4,374)	(4,649)
Domestic deferred tax liability on foreign NOL carryforwards	(6,836)	(10,488)
Deferred Tax Liabilities, Net	(20,654)	(23,617)
Net deferred tax assets	36,408	60,120
Valuation allowance	(2,468)	(2,418)
Net deferred tax assets	33,940	57,702
Long-term deferred tax assets, net	34,723	58,534
Long-term deferred tax liabilities	(783)	(832)
Net deferred tax assets	$ 33,940	$ 57,702

Differences Between Federal Sta

Differences Between Federal Statutory Income Tax Rate and Effective Tax Rates (Detail)	12 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2015
Income Tax Disclosure [Abstract]
Statutory income tax rate	35.00%	35.00%	35.00%
Change in valuation allowance	0.20%	0.70%	(342.80%)
Credits	(3.30%)	(4.10%)	(1.90%)
Foreign taxes	2.00%	2.50%	4.50%
State taxes, net	3.80%	3.70%	4.00%
Permanent differences	3.30%	3.00%	3.90%
Stock based compensation	0.20%	0.30%	0.30%
Rate differential on foreign operations	0.10%		0.20%
Other	1.70%	1.00%	1.60%
Effective tax rate	43.00%	42.10%	(295.20%)

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($)	12 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2015
Income Taxes [Line Items]
Reversal of valuation			$ 101,500,000
Valuation allowance	$ 2,468,000	$ 2,418,000
Stock-based compensation tax deductions in excess of book compensation expense	12,038,000	3,567,000	606,000
Interest and penalties	$ 0	$ 0	$ 0
Earliest Tax Year
Income Taxes [Line Items]
Net operating loss carry forwards expiration period	2,019
Latest Tax Year
Income Taxes [Line Items]
Net operating loss carry forwards expiration period	2,035
Federal
Income Taxes [Line Items]
Net operating loss carry forwards	$ 167,300,000
Research and development credit carry forwards	13,700,000
Net operating loss carry forwards to stock-based compensation	167,300,000
Foreign
Income Taxes [Line Items]
Net operating loss carry forwards	46,900,000
State
Income Taxes [Line Items]
Research and development credit carry forwards	$ 7,800,000

Changes in Valuation Allowance

Changes in Valuation Allowance for Deferred Tax Assets (Detail) - Valuation Allowance of Deferred Tax Assets - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2015
Valuation Allowance [Line Items]
Balance at Beginning of Period	$ 2,418	$ 2,912	$ 102,093
Decreases recorded as benefit to income tax provision		(1,171)	(101,468)
Increases due to foreign net operating loss in certain foreign jurisdictions	50	677	2,287
Balance at End of Period	$ 2,468	$ 2,418	$ 2,912

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail) $ in Millions	Aug. 12, 2016ft²	Feb. 28, 2017USD ($)	Dec. 31, 2015USD ($)	Sep. 30, 2015Patent	Mar. 31, 2017USD ($)	Dec. 31, 2016ft²	Apr. 30, 2014USD ($)
Commitments and Contingencies [Line Items]
Purchase price of property amount			$ 16.5
License agreement, upfront payment							$ 1.5
License agreement, maximum agreed additional payments upon achievement of development milestones							$ 4.5
Magnetic Clutch Patents
Commitments and Contingencies [Line Items]
Patents allegedly infringed upon, number | Patent				2
Pigtail Patents
Commitments and Contingencies [Line Items]
Patents allegedly infringed upon, number | Patent				2
Patent One
Commitments and Contingencies [Line Items]
Patent expiration period					2020-09
Patent Two
Commitments and Contingencies [Line Items]
Patent expiration period					2020-12
Patent Three
Commitments and Contingencies [Line Items]
Patent expiration period					2021-10
Research and Development Expenses
Commitments and Contingencies [Line Items]
License agreement, development milestones payment					$ 0.8
Europe
Commitments and Contingencies [Line Items]
Purchase price of property amount		$ 12.6
Lease Agreements
Commitments and Contingencies [Line Items]
Office space under capital lease | ft²	163,560
Lease agreement termination date	Aug. 31, 2026
Lease description					The Company has options to extend the initial term for three separate periods of five years each.
Capital lease term					15 years
Lease Agreements | Massachusetts
Commitments and Contingencies [Line Items]
Annual rent expense					$ 0.2
Lease expiration period					2022-07
Lease Agreements | Germany
Commitments and Contingencies [Line Items]
Annual rent expense					$ 0.3
Lease expiration period					2024-05
Lease commencement period					2017-05
Lease Agreements | Japan
Commitments and Contingencies [Line Items]
Annual rent expense					$ 0.9
Lease Agreements | Europe
Commitments and Contingencies [Line Items]
Office space under lease | ft²						33,000

Future Minimum Lease Payments U

Future Minimum Lease Payments Under Non-Cancelable Leases (Detail) $ in Thousands	Mar. 31, 2017USD ($)
Leases [Abstract]
2,018	$ 1,311
2,019	1,349
2,020	1,349
2,021	1,373
2,022	1,390
Thereafter	13,746
Total minimum lease payments	20,518
Less amounts representing interest	(4,180)
Total capital lease obligation	16,338
Less current capital lease obligation	(799)
Capital lease obligation, net of current portion	15,539
2,018	1,670
2,019	1,593
2,020	1,532
2,021	1,542
2,022	1,084
Thereafter	752
Total minimum lease payments	$ 8,173

Accrued Expenses (Detail)

Accrued Expenses (Detail) - USD ($) $ in Thousands	Mar. 31, 2017	Mar. 31, 2016
Payables and Accruals [Abstract]
Employee compensation	$ 23,290	$ 18,359
Sales and income taxes	3,180	2,527
Research and development	2,349	1,587
Accrued capital expenditures	2,300
Professional, legal and accounting fees	2,019	1,764
Marketing	1,827	1,146
Warranty	717	998
Other	2,021	2,001
Accrued expenses	$ 37,703	$ 28,382

Segment and Enterprise Wide D67

Segment and Enterprise Wide Disclosures - Additional Information (Detail) $ in Thousands	1 Months Ended	12 Months Ended
	Feb. 28, 2017USD ($)	Mar. 31, 2017USD ($)Segment	Mar. 31, 2016USD ($)	Mar. 31, 2015USD ($)
Segment Reporting Information [Line Items]
Number of business segments | Segment		1
Acquisition cost for property and equipment		$ 50,415	$ 15,624	$ 5,188
International
Segment Reporting Information [Line Items]
Percentage of total product revenue		9.00%	8.00%	10.00%
Long-lived assets		$ 23,200	$ 5,900
Europe
Segment Reporting Information [Line Items]
Acquisition cost for property and equipment	$ 12,600

Summary of Unaudited Quarterly

Summary of Unaudited Quarterly Results of Operations (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2015
Disclosure Unaudited Quarterly Financial Information [Abstract]
Total revenues	$ 124,680	$ 114,674	$ 102,955	$ 102,995	$ 93,957	$ 85,795	$ 76,359	$ 73,432	$ 445,304	$ 329,543	$ 230,311
Cost of product revenue	19,261	18,987	17,309	15,070	14,663	12,744	12,144	10,868	70,627	50,419	39,945
Other operating expenses	76,425	70,284	71,138	66,692	59,481	55,608	51,398	47,533	284,539	214,020
Other income (expense), net	362	423	228	192	414	55	149	116	1,205	734	99
Income before income taxes	29,356	25,826	14,736	21,425	20,227	17,498	12,966	15,147	91,343	65,838	28,765
Income tax (benefit) provision	14,457	10,394	5,861	8,515	9,229	6,943	5,231	6,288	39,227	27,691	(84,923)
Net income	$ 14,899	$ 15,432	$ 8,875	$ 12,910	$ 10,998	$ 10,555	$ 7,735	$ 8,859	$ 52,116	$ 38,147	$ 113,688
Basic net income per share	$ 0.34	$ 0.36	$ 0.21	$ 0.30	$ 0.26	$ 0.25	$ 0.18	$ 0.21	$ 1.21	$ 0.90	$ 2.80
Diluted net income per share	$ 0.33	$ 0.34	$ 0.20	$ 0.29	$ 0.24	$ 0.23	$ 0.17	$ 0.20	$ 1.17	$ 0.85	$ 2.65