Cray (CRAY) 10-K 11 Feb 16 2015 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2015	Feb. 08, 2016	Jun. 30, 2015
Document and Entity Information [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2015
Document Fiscal Period Focus	FY
Document Fiscal Year Focus	2,015
Entity Registrant Name	CRAY INC
Entity Central Index Key	949,158
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		40,688,282
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Well-known Seasoned Issuer	Yes
Entity Public Float			$ 1,167,319,515

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Current assets:
Cash and cash equivalents	$ 266,660	$ 112,633
Restricted cash	1,651	16,874
Short-term investments	14,925	16,289
Accounts and other receivables, net	124,719	165,113
Inventory	113,655	143,632
Deferred tax assets, net	38,628	36,073
Prepaid expenses and other current assets	21,048	17,948
Total current assets	581,286	508,562
Noncurrent Assets:
Long-term restricted cash	1,655	0
Long-term investment in sales-type lease, net	18,317	31,089
Property and equipment, net	31,079	34,793
Service inventory, net	3,090	1,868
Goodwill	14,182	14,182
Purchased intangible assets, net	2,525	3,895
Deferred tax asset	26,016	41,414
Other non-current assets	16,025	15,631
TOTAL ASSETS	694,175	651,434
Current liabilities:
Accounts payable	27,837	48,699
Accrued payroll and related expenses	27,452	16,054
Other accrued liabilities	24,079	16,285
Deferred revenue	86,731	65,910
Total current liabilities	166,099	146,948
Noncurrent Liabilities:
Long-term deferred revenue	33,306	47,588
Other non-current liabilities	2,260	3,044
TOTAL LIABILITIES	201,665	197,580
Shareholders’ equity:
Preferred stock — Authorized and undesignated, 5,000,000 shares; no shares issued or outstanding	0	0
Common stock and additional paid-in capital, par value $.01 per share — Authorized, 75,000,000 shares; issued and outstanding 39,435,215 and 36,763,379 shares, respectively	610,279	598,390
Accumulated other comprehensive income	7,642	6,503
Accumulated deficit	(125,411)	(151,039)
TOTAL SHAREHOLDERS’ EQUITY	492,510	453,854
TOTAL LIABILITIES AND SHAREHOLDERS’ EQUITY	$ 694,175	$ 651,434

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2015	Dec. 31, 2014
Statement of Financial Position [Abstract]
Preferred stock, shares authorized	5,000,000	5,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value (dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized	75,000,000	75,000,000
Common stock and additional paid-in capital, shares issued	40,693,707	40,822,377
Common stock and additional paid-in capital, shares outstanding	40,693,707	40,822,377

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Revenue:
Product	$ 601,294	$ 460,748	$ 436,330
Service	123,395	100,858	89,419
Total revenue	724,689	561,606	525,749
Cost of revenue:
Cost of product revenue	426,821	321,554	298,244
Cost of service revenue	72,185	55,638	43,179
Total cost of revenue	499,006	377,192	341,423
Gross profit	225,683	184,414	184,326
Operating expenses:
Research and development, net	96,563	94,048	87,728
Sales and marketing	60,150	57,785	51,345
General and administrative	27,966	23,381	23,603
Total operating expenses	184,679	175,214	162,676
Income from operations	41,004	9,200	21,650
Other income (expense), net	365	(9)	(1,378)
Interest income (expense), net	1,408	506	757
Income before income taxes	42,777	9,697	21,029
Income tax benefit (expense)	(15,240)	52,626	11,194
Net income	$ 27,537	$ 62,323	$ 32,223
Basic net income per common share (dollars per share)	$ 0.70	$ 1.61	$ 0.85
Diluted net income per common share (dollars per share)	$ 0.68	$ 1.54	$ 0.81
Basic weighted average shares outstanding (shares)	39,257	38,634	37,832
Diluted weighted average shares outstanding (shares)	40,691	40,435	39,776

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Statement of Comprehensive Income [Abstract]
Net income	$ 27,537	$ 62,323	$ 32,223
Other Comprehensive Income (Loss), Net of Tax [Abstract]
Unrealized loss on available-for-sale investments	(20)	12	46
Foreign currency translation adjustments	(394)	(1,188)	(1,044)
Unrealized gain (loss) on cash flow hedges	5,251	8,475	(4,292)
Reclassification adjustments on cash flow hedges included in net income	(3,698)	(1,649)	962
Other comprehensive income (loss)	1,139	5,650	(4,328)
Comprehensive income	$ 28,676	$ 67,973	$ 27,895

Consolidated Statements of Shar

Consolidated Statements of Shareholders’ Equity - USD ($) $ in Thousands	Total	Common Stock and Additional Paid In Capital	Accumulated Other Comprehensive Income	Accumulated Deficit
Balance, shares at Dec. 31, 2012		39,435,000
Balance at Dec. 31, 2012	$ 340,546	$ 577,938	$ 5,181	$ (242,573)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of shares under employee stock purchase plan, shares		25,000
Issuance of shares under employee stock purchase plan	$ 517	$ 517
Exercise of stock options, shares	495,221	495,000
Exercise of stock options	$ 3,161	$ 3,161
Restricted shares issued for compensation, net of forfeitures, shares		(515,000)
Restricted shares issued for compensation, net of forfeitures and taxes	(3,771)	$ (2,612)		1,159
Share-based compensation	7,239	$ 7,239
Other comprehensive income	(4,328)		(4,328)
Net income	32,223			32,223
Balance, shares at Dec. 31, 2013		40,470,000
Balance at Dec. 31, 2013	375,587	$ 586,243	853	(211,509)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of shares under employee stock purchase plan, shares		21,000
Issuance of shares under employee stock purchase plan	$ 611	$ 611
Exercise of stock options, shares	411,352	411,000
Exercise of stock options	$ 3,086	$ 3,086
Restricted shares issued for compensation, net of forfeitures, shares		(80,000)
Restricted shares issued for compensation, net of forfeitures and taxes	(3,767)	$ (1,914)		(1,853)
Share-based compensation	10,364	$ 10,364
Other comprehensive income	5,650		5,650
Net income	$ 62,323			62,323
Balance, shares at Dec. 31, 2014	40,822,377	40,822,000
Balance at Dec. 31, 2014	$ 453,854	$ 598,390	6,503	(151,039)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of shares under employee stock purchase plan, shares		27,000
Issuance of shares under employee stock purchase plan	$ 711	$ 711
Exercise of stock options, shares	229,118	229,000
Exercise of stock options	$ 2,289	$ 2,289
Restricted shares issued for compensation, net of forfeitures, shares		(384,000)
Restricted shares issued for compensation, net of forfeitures and taxes	(4,373)	$ (2,464)		(1,909)
Share-based compensation	11,353	$ 11,353
Other comprehensive income	1,139		1,139
Net income	$ 27,537			27,537
Balance, shares at Dec. 31, 2015	40,693,707	40,694,000
Balance at Dec. 31, 2015	$ 492,510	$ 610,279	$ 7,642	$ (125,411)

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Operating activities:
Net income	$ 27,537	$ 62,323	$ 32,223
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Depreciation and amortization	17,017	16,324	14,242
Share-based compensation expense	11,353	10,364	7,239
Deferred income taxes	12,103	(53,204)	(13,175)
Other	1,945	4,159	2,936
Cash (used in) provided by operations due to changes in operating assets and liabilities:
Accounts and other receivables	36,665	17,450	(169,753)
Long-term investment in sales-type lease, net	11,510	(32,889)	0
Inventory	21,292	(54,147)	(10,780)
Prepaid expenses and other assets	(3,972)	(9,349)	(2,670)
Accounts payable	(19,849)	14,504	(509)
Accrued payroll and related expenses and other accrued liabilities	23,841	(5,237)	8,422
Deferred revenue	8,314	(28,407)	44,475
Net cash (used in) provided by operating activities	147,756	(58,109)	(87,350)
Investing activities:
Sales/maturities of short-term investments	16,229	53,608	139,277
Purchases of available-for-sale investments	(14,991)	(56,064)	(85,162)
Decrease in restricted cash	13,445	(3,106)	(13,768)
Purchases of property and equipment	(7,467)	(17,193)	(13,136)
Net cash provided by (used in) investing activities	7,216	(22,755)	27,211
Financing activities:
Proceeds from issuance of common stock through employee stock purchase plan	711	611	517
Purchase of employee restricted shares to fund related statutory tax withholding	(4,373)	(3,767)	(3,771)
Proceeds from exercise of options	2,289	3,086	3,161
Net cash provided by financing activities	(1,373)	(70)	(93)
Effect of foreign exchange rate changes on cash and cash equivalents	428	934	(200)
Net increase (decrease) in cash and cash equivalents	154,027	(80,000)	(60,432)
Cash and cash equivalents:
Beginning of period	112,633	192,633	253,065
End of period	266,660	112,633	192,633
Supplemental disclosure of cash flow information:
Cash paid for interest	4	5	3
Cash paid for income taxes	3,890	2,935	2,611
Non-cash investing and financing activities:
Inventory transfers to fixed assets and service inventory	$ 8,177	$ 3,313	$ 4,530

Description of Business

Description of Business	12 Months Ended
	Dec. 31, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Description of Business	DESCRIPTION OF BUSINESS Cray Inc., or Cray, or the Company, designs, develops, manufactures, markets and services the high-end of the high performance computing, or HPC, market, primarily categories of systems commonly known as supercomputers, and provides storage and data analytics solutions. The Company also provides software, system maintenance and support services and engineering services related to supercomputer systems and storage and data analytics solutions. Cray’s supercomputer systems address challenging scientific, engineering, commercial and national security computing problems. The Company’s customers include foreign and domestic governments and government-funded entities, academic institutions and commercial entities.

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2015
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Accounting Principles The consolidated financial statements and accompanying notes are prepared in accordance with accounting principles generally accepted in the United States of America, or GAAP. Principles of Consolidation The consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries. All material intercompany balances and transactions have been eliminated. Reclassifications Certain prior year amounts have been reclassified to conform with the current year presentation. There has been no impact on previously reported net income or shareholders’ equity from such reclassifications. Use of Estimates The preparation of financial statements in accordance with GAAP requires management to make estimates and assumptions that affect the amounts reported in the Company’s consolidated financial statements and accompanying notes. Actual results could differ materially from those estimates. Cash, Cash Equivalents and Restricted Cash Cash and cash equivalents consist of highly liquid financial instruments that are readily convertible to cash and have maturities of three months or less at the time of acquisition. The Company maintains cash and cash equivalent balances with financial institutions that exceed federally insured limits. As of December 31, 2015 and 2014 , the Company had $1.7 million and $16.9 million , respectively, in short-term restricted cash. As of December 31, 2015 , the Company had $1.7 million in long-term restricted cash. The restricted cash is associated with certain letters of credit outstanding to secure customer prepayments. Investments The Company’s investments consist primarily of commercial paper, corporate debt, and other debt securities. Debt securities are classified as available-for-sale and are reported at fair value with unrealized gains and losses, net of applicable taxes, recorded in accumulated other comprehensive income, a component of shareholders’ equity. The realized gains and losses for available-for-sale securities are included in other income and expense in the Consolidated Statements of Operations. Realized gains and losses are calculated based on the specific identification method. The Company monitors its investment portfolio for impairment on a periodic basis. When the carrying value of an investment in debt securities exceeds its fair value and the decline in value is determined to be an other-than-temporary decline, and when the Company does not intend to sell the debt security and it is not more likely than not that the Company will be required to sell the debt securities prior to recovery of its amortized cost basis, the Company records an impairment charge in the amount of the credit loss and the balance, if any, to other comprehensive income (loss). Investments that mature between three months and one year from the purchase date are initially classified as short-term investments in the Consolidated Balance Sheet. Investments that mature beyond one year from the purchase date are initially classified as long-term investments in the Consolidated Balance Sheet. Foreign Currency Derivatives The Company uses foreign currency exchange contracts to hedge certain foreign currency exposures. Foreign currency exchange contracts are cash flow hedges of the Company’s foreign currency exposures on certain revenue contracts and are recorded at the contract’s fair value. Most of the Company’s foreign currency exchange contracts are designated as cash flow hedges for the purposes of hedge accounting treatment and any gains or losses on the effective portion of the foreign currency exchange contract is initially reported in “Accumulated other comprehensive income,” a component of shareholders’ equity, with a corresponding asset or liability recorded based on the fair value of the foreign currency exchange contract. When the hedged transaction is recognized, any unrecognized gains or losses on the hedged transaction are reclassified into results of operations in the same period. Any hedge ineffectiveness is recorded to operations in the current period. The Company measures hedge effectiveness by comparing changes in fair values of the foreign currency exchange contract and expected cash flows based on changes in the spot prices of the underlying currencies. Cash flows from foreign currency exchange contracts accounted for as cash flow hedges are classified in the same category as the cash flows from the items being hedged. Unrealized gains or losses related to foreign currency exchange contracts that are not designated as cash flow hedges for the purposes of hedge accounting treatment are recorded in the Consolidated Statement of Operations and are generally offset by foreign currency adjustments on related receivables. The Company does not use derivative financial instruments for speculative purposes. Concentration of Credit Risk Financial instruments that potentially subject the Company to significant concentrations of credit risk consist primarily of cash and cash equivalents, available-for-sale investments, accounts receivable, short-term and long-term restricted cash and foreign currency exchange contracts. The Company maintains cash and cash equivalents, available-for-sale securities and foreign currency exchange contracts with various financial institutions. As part of its risk management process, the Company performs periodic evaluations of the relative credit standing of the financial institutions. The Company has not sustained any credit losses from instruments held at financial institutions. The Company utilizes foreign currency exchange contracts to protect against the effects of foreign currency fluctuations. Such contracts involve the risk of non-performance by the counterparty, which could result in a material loss. The Company currently derives a significant portion of its revenue from sales of products and services to the U.S. Government. See Note 17 — Segment Information for additional information. Given the type of customers, the Company does not believe its accounts receivable represent significant credit risk. The Company currently has a long-term investment in a sales-type lease it entered into with one of its customers. See Note 7 — Sales-type Lease for additional information. Given the credit standing of the customer, the Company does not believe that this investment represents a significant credit risk. Other Concentration The Company obtains certain components from single-source suppliers due to technology, availability, price, quality or other considerations. The loss of a single-source supplier, the single-source supplier’s inability to deliver the required components or intellectual property due to natural disaster or other reasons, the deterioration of the relationship with a single-source supplier, or any unilateral modification of contract terms under which the Company is supplied components by a single-source supplier could have a significant adverse effect on the Company’s revenue and gross margins. Accounts Receivable Accounts receivable are stated at principal amounts and are primarily comprised of amounts contractually due from customers for products and services and amounts due from government research and development contracts. The Company provides an allowance for doubtful accounts based on an evaluation of customer past due account balances. In determining whether to record an allowance for a specific customer, the Company considers a number of factors, including prior payment history and financial information for the customer. Fair Values of Financial Instruments The Company measures certain financial assets and liabilities at fair value based on the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants. The Company’s financial instruments primarily consist of debt securities, time deposits, money market funds, and foreign currency derivatives. See Note 3 — Fair Value Measurement for a further discussion on fair value of financial instruments. Inventories Inventories are valued at the lower of cost or market, with cost computed on a first-in, first-out basis (FIFO). The Company regularly evaluates the technological usefulness and anticipated future demand for various inventory components and the expected use of the inventory. When the Company determines it is not likely the cost of inventory items will be recovered through future sales, the Company writes-down the related inventory to its estimated market value. In connection with certain of its sales agreements, the Company may receive used equipment from a customer. This inventory generally will be recorded at no value based on the expectation that the Company will not be able to resell or otherwise use the equipment. In the event that the Company has a specific contractual plan for resale at the date the inventory is acquired, the inventory is recorded at its estimated fair value. Property and Equipment and Intangible Assets, Net Property and equipment are recorded at cost less accumulated depreciation and amortization. Additions and improvements are capitalized and maintenance and repairs are expensed as incurred. Depreciation is calculated on a straight-line basis over the estimated useful lives of the related assets, ranging from eighteen months to seven years for furniture and fixtures, three years for computer equipment, and eight to twenty-five years for buildings and land improvements. Leasehold improvements are depreciated over the life of the lease or asset, whichever is shorter. The Company amortizes purchased intangible assets with finite lives using the straight-line method over the estimated economic lives of the assets, ranging from two to ten years . Service Spares Service spares are valued at the lower of cost or market and represent inventory used to support service and maintenance agreements with customers. As inventory is utilized, replaced items are returned to the Company and are either repaired or scrapped. Costs incurred to repair inventory to a usable state are charged to expense as incurred. Service spares are recorded at cost and amortized over the estimated service life of the related product platform (generally four years ). Impairment of Long-Lived Assets and Intangibles The Company evaluates property, plant and equipment and intangible assets with finite lives for impairment whenever events or changes in circumstances indicate the carrying value of an asset may not be recoverable. The Company assesses the recoverability of the assets based on the undiscounted future cash flow the assets are expected to generate and recognizes an impairment loss when estimated undiscounted future cash flow expected to result from the use of the asset plus net proceeds expected from disposition of the asset, if any, are less than the carrying value of the asset. When the Company identifies an impairment, the carrying value of the asset is reduced to its estimated fair value based on a discounted cash flow approach or, when available and appropriate, to comparable market values. Goodwill Goodwill is not amortized but is tested for impairment at least annually. The Company reviews goodwill for impairment annually at the beginning of its fourth fiscal quarter and whenever events or changes in circumstances indicate the carrying value of the asset may not be recoverable. The goodwill impairment test consists of a two-step process, if necessary. However, the Company first assesses qualitative factors to determine whether it is more likely than not that the fair value of a reporting unit is less than its carrying amount as a basis for determining whether it is necessary to perform the two-step goodwill impairment test described in ASC Topic 350. The more likely than not threshold is defined as having a likelihood of more than 50 percent. If, after assessing the totality of events or circumstances, the Company determines that it is not more likely than not that the fair value of a reporting unit is less than its carrying amount, then performing the two-step impairment test is unnecessary and goodwill is considered to be unimpaired. However, if based on the qualitative assessment the Company concludes that it is more likely than not that the fair value of a reporting unit is less than its carrying amount, the Company will proceed with performing the two-step process. In step one, the Company determines the fair value of each reporting unit and compares it to its carrying value. If the fair value of the reporting unit exceeds the carrying value of the net assets assigned to that unit, goodwill is not impaired and no further testing is performed. If the carrying value of the net assets assigned to the reporting unit exceeds the fair value of the reporting unit, then the Company must perform the second step of the impairment test in order to determine the implied fair value of the reporting unit’s goodwill. If the carrying value of a reporting unit’s goodwill exceeds its implied fair value, the Company records an impairment loss equal to the difference. The Company performed its qualitative assessment during the fourth fiscal quarter of 2015 and concluded that it was more likely than not that the fair values of its reporting units were greater than their carrying amounts. After reaching this conclusion, the two-step impairment test was unnecessary and no further testing was performed. The qualitative factors that were considered included, but were not limited to, general economic conditions, outlook for the HPC and big data markets, recent and forecasted financial performance and the price of the Company’s common stock. Business Combinations The Company accounts for business combinations using the acquisition method of accounting and allocates the purchase price to the tangible and intangible assets acquired and the liabilities assumed based upon their estimated fair values at the acquisition date. The difference between the purchase price and the fair value of the net assets acquired is recorded as goodwill. The Company uses estimates and assumptions to accurately value assets acquired and liabilities assumed at the acquisition date. During the measurement period, which may be up to one year from the acquisition date, any refinements made to the fair value of the assets and liabilities assumed are recorded with retrospective effect. The fair values of intangible assets acquired are estimated using a discounted cash flow approach with Level 3 inputs. Under this method, an intangible asset’s fair value is equal to the present value of the incremental after-tax cash flows (excess earnings) attributable solely to the intangible asset over its remaining useful life. To calculate fair value, the Company uses risk-adjusted cash flows discounted at rates considered appropriate given the inherent risks associated with each type of asset. The Company believes the level and timing of cash flows appropriately reflects market participant assumptions. Revenue Recognition The Company recognizes revenue, including transactions under sales-type leases, when it is realized or realizable and earned. The Company considers revenue realized or realizable and earned when it has persuasive evidence of an arrangement, delivery has occurred, the sales price is fixed or determinable, and collectibility is reasonably assured. Delivery does not occur until the products have been shipped or services provided to the customer, risk of loss has transferred to the customer, and, where applicable, a customer acceptance has been obtained. The sales price is not considered to be fixed or determinable until all material contingencies related to the sales have been resolved. The Company records revenue in the Consolidated Statements of Operations net of any sales, use, value added or certain excise taxes imposed by governmental authorities on specific sales transactions. In addition to the aforementioned general policy, the following are the Company’s statements of policy with regard to multiple-element arrangements and specific revenue recognition policies for each major category of revenue. Multiple-Element Arrangements. The Company commonly enters into revenue arrangements that include multiple deliverables of its product and service offerings due to the needs of its customers. Products may be delivered in phases over time periods which can be as long as five years . Maintenance services generally begin upon acceptance of the first equipment delivery and future deliveries of equipment generally have an associated maintenance period. The Company considers the maintenance period to commence upon acceptance of the product or installation in situations where a formal acceptance is not required, which may include a warranty period and accordingly allocates a portion of the arrangement consideration as a separate deliverable which is recognized as service revenue over the entire service period. Other services such as training and engineering services can be delivered as a discrete delivery or over the term of the contract. A multiple-element arrangement is separated into more than one unit of accounting if the following criteria are met: • The delivered item(s) has value to the customer on a standalone basis; and • If the arrangement includes a general right of return relative to the delivered item(s), delivery or performance of the undelivered item(s) is considered probable and substantially in the control of the Company. If these criteria are met for each element, the arrangement consideration is allocated to the separate units of accounting based on each unit’s relative selling price. If these criteria are not met, the arrangement is accounted for as one unit of accounting which would result in revenue being recognized ratably over the contract term or being deferred until the earlier of when such criteria are met or when the last undelivered element is delivered. The Company follows a selling price hierarchy in determining the best estimate of the selling price of each deliverable. Certain products and services are sold separately in standalone arrangements for which the Company is sometimes able to determine vendor specific objective evidence, or VSOE. The Company determines VSOE based on normal pricing and discounting practices for the product or service when sold separately. When the Company is not able to establish VSOE for all deliverables in an arrangement with multiple elements, the Company attempts to establish the selling price of each remaining element based on third-party evidence, or TPE. The Company’s inability to establish VSOE is often due to a relatively small sample of customer contracts that differ in system size and contract terms which can be due to infrequently selling each element separately, not pricing products within a narrow range, or only having a limited sales history, such as in the case of certain advanced and emerging technologies. TPE is determined based on the Company’s prices or competitor prices for similar deliverables when sold separately. However, the Company is often unable to determine TPE, as the Company’s offerings usually contain a significant level of customization and differentiation from those of competitors and the Company is often unable to reliably determine what similar competitor products’ selling prices are on a standalone basis. When the Company is unable to establish selling price using VSOE or TPE, the Company uses estimated selling price, or ESP, in its allocation of arrangement consideration. The objective of ESP is to determine the price at which the Company would transact a sale if the product or service were sold on a standalone basis. In determining ESP, the Company uses the cost to provide the product or service plus a margin, or considers other factors. When using cost plus a margin, the Company considers the total cost of the product or service, including customer-specific and geographic factors. The Company also considers the historical margins of the product or service on previous contracts and several factors including any changes to pricing methodologies, competitiveness of products and services and cost drivers that would cause future margins to differ from historical margins. Products . The Company most often recognizes revenue from sales of products upon customer acceptance of the system. Where formal acceptance is not required, the Company recognizes revenue upon delivery or installation. When the product is part of a multiple element arrangement, the Company allocates a portion of the arrangement consideration to product revenue based on estimates of selling price. Services . Maintenance services are provided under separate maintenance contracts with customers. These contracts generally provide for maintenance services for one year , although some are for multi-year periods, often with prepayments for the term of the contract. The Company considers the maintenance period to commence upon acceptance of the product or installation in situations where a formal acceptance is not required, which may include a warranty period. When service is part of a multiple element arrangement, the Company allocates a portion of the arrangement consideration to maintenance service revenue based on estimates of selling price. Maintenance contracts that are billed in advance of revenue recognition are recorded as deferred revenue. Maintenance revenue is recognized ratably over the term of the maintenance contract. Revenue from engineering services is recognized as services are performed. Project Revenue . Revenue from design and build contracts is recognized under the percentage-of-completion, or POC, method. Under the POC method, revenue is recognized based on the costs incurred to date as a percentage of the total estimated costs to fulfill the contract. If circumstances arise that change the original estimates of revenues, costs, or extent of progress toward completion, revisions to the estimates are made. These revisions may result in increases or decreases in estimated revenues or costs, and such revisions are recorded in income in the period in which the circumstances that gave rise to the revision become known by management. The Company performs ongoing profitability analyses of its contracts accounted for under the POC method in order to determine whether the latest estimates of revenue, costs and extent of progress require updating. If at any time these estimates indicate that the contract will be unprofitable, the entire estimated loss for the remainder of the contract is recorded immediately. The Company records revenue from certain research and development contracts which include milestones using the milestone method if the milestones are determined to be substantive. A milestone is considered to be substantive if management believes there is substantive uncertainty that it will be achieved and the milestone consideration meets all of the following criteria: • It is commensurate with either of the following: • The Company’s performance to achieve the milestone; or • The enhancement of value of the delivered item or items as a result of a specific outcome resulting from the Company’s performance to achieve the milestone. • It relates solely to past performance. • It is reasonable relative to all of the deliverables and payment terms (including other potential milestone consideration) within the arrangement. The individual milestones are determined to be substantive or non-substantive in their entirety and milestone consideration is not bifurcated. Revenue from projects is classified as Product Revenue or Service Revenue, based on the nature of the work performed. Nonmonetary Transactions . The Company values and records nonmonetary transactions at the fair value of the asset surrendered unless the fair value of the asset received is more clearly evident, in which case the fair value of the asset received is used. Sales-type leases When the Company leases a system to a customer, the accounting involves specific determinations, which often involve complex provisions and significant judgments. The four criteria of the accounting standard that the Company uses in the determination of whether a lease is a sales-type lease or an operating lease are: (a) a review of the lease term to determine if it is equal to or greater than 75% of the economic life of the system; (b) a review of the minimum lease payments to determine if they are equal to or greater than 90% of the fair value of the system; (c) a determination of whether or not the lease transfers ownership to the lessee at the end of the lease term; and (d) a determination of whether or not the lease contains a bargain purchase option. If the lease transaction meets one of the four criteria, then it is recorded as a sales-type lease; otherwise it is an operating lease. Additionally, the Company assesses whether collectibility of the lease payments is reasonably assured and whether there are any significant uncertainties related to costs that it has yet to incur with respect to the lease. The Company considers the economic lives of most of its products to range from three to four years. There is no significant after-market for the Company’s used products and the Company believes that the economic lives are representative of the periods during which its products are expected to be economically usable, with normal service, for the purposes for which they were intended. Residual values are not significant. The discount rate implicit in the sales-type lease is used to calculate the present value of minimum lease payments, which the Company records as a lease receivable. The minimum lease payment consists of the gross lease payments net of executory costs and contingencies, if any. While revenue is recognized at inception of the lease, the cash flow from the sales-type lease occurs over the course of the lease, which results in interest income. Unearned interest income is recorded at inception of the lease and amortized over the lease term using the effective interest method. Foreign Currency Translation The Company uses the U.S. dollar predominantly as its functional currency. Assets and liabilities of foreign subsidiaries that have a functional currency denominated in non-U.S. dollars are translated into U.S. dollars at year-end exchange rates, and revenue and expenses of these foreign subsidiaries are translated at average rates prevailing during the year. Translation adjustments are included in “Accumulated other comprehensive income,” a separate component of shareholders’ equity. Transaction gains and losses arising from transactions denominated in a currency other than the functional currency of the entity involved are included in “Other (income) expense, net” in the accompanying Consolidated Statements of Operations. Net transaction gains were $1.6 million and $2.1 million for 2015 and 2014 , respectively, and net transaction losses were $1.3 million for 2013 . Research and Development Research and development expenses include costs incurred in the development and production of hardware and software, costs incurred to enhance and support existing product features, costs incurred to support and improve development processes, and costs related to future product development. Research and development costs are expensed as incurred, and may be offset by co-funding from third parties. The Company may also enter into arrangements whereby it makes advance, non-refundable payments to a vendor to perform certain research and development services. These payments are deferred and recognized over the vendor’s estimated performance period. Amounts to be received under co-funding arrangements with the U.S. government or others are based on either contractual milestones or costs incurred. These co-funding milestone payments are recognized in operations as performance is estimated to be completed and are measured as milestone achievements occur or as costs are incurred. These estimates are reviewed on a periodic basis and are subject to change, including in the near term. If an estimate is changed, net research and development expense could be impacted significantly. The Company does not record a receivable from the U.S. government prior to completing the requirements necessary to bill for a milestone or cost reimbursement. Funding from the U.S. government is subject to certain budget restrictions and milestones may be subject to completion risk, and as a result, there may be periods in which research and development costs are expensed as incurred for which no reimbursement is recorded, as milestones have not been completed or the U.S. government has not funded an agreement. Accordingly, there can be substantial variability in the amount of net research and development expenses from quarter to quarter and year to year. The Company classifies amounts to be received from funded research and development projects as either revenue or a reduction to research and development expense based on the specific facts and circumstances of the contractual arrangement, considering total costs expected to be incurred compared to total expected funding and the nature of the research and development contractual arrangement. In the event that a particular arrangement is determined to represent revenue, the corresponding research and development costs are classified as cost of revenue. Income Taxes Deferred tax assets and liabilities are determined based on differences between financial reporting and tax bases of assets and liabilities and operating loss and tax credit carryforwards and are measured using the enacted tax rates and laws that will be in effect when the differences and carryforwards are expected to be recovered or settled. A valuation allowance for deferred tax assets is provided when the Company estimates that it is more likely than not that all or a portion of the deferred tax assets may not be realized through future operations. This assessment is based upon consideration of available positive and negative evidence, which includes, among other things, recent results of operations and expected future profitability. The Company considers its actual historical results over several years to have stronger weight than other more subjective indicators, including forecasts, when considering whether to establish or reduce a valuation allowance on deferred tax assets. The Company recognizes the income tax benefit from a tax position only if it is more likely than not that the tax position will be sustained on examination by the applicable taxing authorities, based on the technical merits of the Company’s position. The tax benefit recognized in the financial statements from such a position is measured based on the largest benefit that has a greater than fifty percent likelihood of being realized upon ultimate settlement. Estimated interest and penalties are recorded as a component of interest expense and other expense, respectively. As of December 31, 2015 , the Company had approximately $74.0 million of net deferred tax assets before application of a valuation allowance. As of December 31, 2015 , net deferred tax assets after reduction by the valuation allowance of $9.5 million were $64.5 million . During the year ended December 31, 2014, the Company reduced substantially all of the remaining valuation allowance held against the Company’s U.S. deferred tax assets. The Company continues to provide a valuation allowance against specific U.S. deferred tax assets and a valuation allowance against deferred tax assets arising in a limited number of foreign jurisdictions as the realization of such assets is not considered to be more likely than not at this time. In a future period, the Company’s assessment of the realizability of its deferred tax assets and therefore the appropriateness of the valuation allowance could change based on an assessment of all available evidence, both positive and negative in that future period. If the Company’s conclusion about the realizability of its deferred tax assets and therefore the appropriateness of the valuation allowance changes in a future period, the Company could record a substantial tax provision or benefit in its Consolidated Statement of Operations when that occurs. Share-Based Compensation The Company measures compensation cost for share-based payment awards at fair value and recognizes it as compensation expense over the service period for awards expected to vest. Share-ba

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2015
Fair Value Disclosures [Abstract]
Fair Value Measurements	FAIR VALUE MEASUREMENTS Under FASB Accounting Standards Codification Topic 820, Fair Value Measurements and Disclosures , based on the observability of the inputs used in the valuation techniques used to determine the fair value of certain financial assets and liabilities, the Company is required to provide the following information according to the fair value hierarchy. The fair value hierarchy ranks the quality and reliability of the information used to determine fair values. In general, fair values determined by Level 1 inputs utilize quoted prices (unadjusted) in active markets for identical assets or liabilities. Fair values determined by Level 2 inputs utilize observable inputs other than Level 1 prices, such as quoted prices for similar assets or liabilities, quoted prices in markets that are not active or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the related assets or liabilities. Fair values determined by Level 3 inputs are unobservable data points for the asset or liability, and include situations where there is little, if any, market activity for the asset or liability. The following table presents information about the Company’s financial assets and liabilities that have been measured at fair value on a recurring basis as of December 31, 2015 and 2014 , and indicates the fair value hierarchy of the valuation inputs utilized to determine such fair value (in thousands): Description Fair Value Quoted Prices in Active Markets (Level 1) Significant Other Observable Inputs (Level 2) Assets: Cash and cash equivalents and restricted cash $ 269,966 $ 269,966 $ — Available-for-sale investments (1) 14,925 14,925 — Foreign currency exchange contracts (2) 11,602 — 11,602 Assets measured at fair value at December 31, 2015 $ 296,493 $ 284,891 $ 11,602 Liabilities: Foreign currency exchange contracts (3) 3 — 3 Liabilities measured at fair value at December 31, 2015 $ 3 $ — $ 3 Description Fair Value Quoted Prices in Active Markets (Level 1) Significant Other Observable Inputs (Level 2) Assets: Cash and cash equivalents and restricted cash $ 129,507 $ 129,507 $ — Available-for-sale investments (1) 16,289 16,289 — Foreign currency exchange contracts (2) 11,079 — 11,079 Assets measured at fair value at December 31, 2014 $ 156,875 $ 145,796 $ 11,079 Liabilities: Foreign currency exchange contracts (3) 2,139 — 2,139 Liabilities measured at fair value at December 31, 2014 $ 2,139 $ — $ 2,139 _______________________________ (1) Included in “Short-term investments” on the Company’s Consolidated Balance Sheets. (2) Included in “Prepaid expenses and other current assets” and “Other non-current assets” on the Company’s Consolidated Balance Sheets. (3) Included in “Other accrued liabilities” and “Other non-current liabilities” on the Company’s Consolidated Balance Sheets. Foreign Currency Derivatives The Company may enter into foreign currency derivatives to hedge future cash receipts on certain sales transactions that are payable in foreign currencies. As of December 31, 2015 and 2014 , the Company had outstanding foreign currency exchange contracts that were designated and accounted for as cash flow hedges of anticipated future cash receipts on sales contracts payable in foreign currencies. The outstanding notional amounts were approximately (in millions): December 31, 2015 December 31, 2014 British Pounds (GBP) 39.2 77.9 Euros (EUR) 6.0 40.7 Swiss Francs (CHF) 33.0 0.9 Singapore Dollars (SGD) — 0.1 Swedish Krona (SEK) — 84.8 The Company had hedged foreign currency exposure related to these designated cash flow hedges of approximately $107.3 million and $192.5 million as of December 31, 2015 and December 31, 2014 , respectively. As of December 31, 2015 , the Company had outstanding foreign currency exchange contracts that had been dedesignated for the purposes of hedge accounting treatment. The outstanding notional amounts were approximately (in millions): December 31, 2015 December 31, 2014 British Pounds (GBP) 31.5 28.3 Euros (EUR) 3.8 — Swiss Francs (CHF) 0.3 — Japanese Yen (JPY) 274.0 — The foreign currency exposure related to these contracts was approximately $55.6 million as of December 31, 2015 and $43.4 million as of December 31, 2014 . Unrealized gains or losses related to these dedesignated contracts are recorded in the Consolidated Statements of Operations and are generally offset by foreign currency adjustments on related receivables. These foreign currency exchange contracts are considered to be economic hedges. Cash receipts associated with the hedged contracts are expected to be received from 2016 through 2018, during which time the revenue on the associated sales contracts is expected to be recognized, or in the case of receivables denominated in a foreign currency, the receivables balances will be collected. Any gain or loss on hedged foreign currency will be recognized at the time of customer acceptance, or in the case of receivables denominated in a foreign currency, each period during which hedged receivables denominated in a foreign currency are outstanding. As of December 31, 2015 and 2014 , the fair value of outstanding foreign currency exchange contracts totaled a net gain of $11.6 million and $8.9 million , respectively. Fair values of derivative instruments designated as cash flow hedges (in thousands): Hedge Classification Balance Sheet Location Fair Value Fair Value Foreign currency exchange contracts Prepaid expenses and other current assets $ 3,956 $ 5,360 Foreign currency exchange contracts Other non-current assets 5,183 5,717 Foreign currency exchange contracts Other accrued liabilities — (1,219 ) Foreign currency exchange contracts Other non-current liabilities (2 ) (152 ) Total fair value of derivative instruments designated as cash flow hedges $ 9,137 $ 9,706 As of December 31, 2015 and 2014 , unrecognized gains, net of tax, of $6.0 million and $4.4 million , respectively, were included in “Accumulated other comprehensive income” on the Company’s Consolidated Balance Sheets. Fair values of derivative instruments not designated as cash flow hedges (in thousands): Hedge Classification Balance Sheet Location Fair Value Fair Value Foreign currency exchange contracts Prepaid expenses and other current assets $ 1,807 $ 2 Foreign currency exchange contracts Other non-current assets 656 — Foreign currency exchange contracts Other accrued liabilities (1 ) (235 ) Foreign currency exchange contracts Other non-current liabilities — (533 ) Total fair value of derivative instruments not designated as cash flow hedges $ 2,462 $ (766 )

Accumulated Other Comprehensive

Accumulated Other Comprehensive Income	12 Months Ended
	Dec. 31, 2015
Other Comprehensive Income (Loss), Net of Tax [Abstract]
Accumulated Other Comprehensive Income	ACCUMULATED OTHER COMPREHENSIVE INCOME The following table shows the impact on product revenue of reclassification adjustments from accumulated other comprehensive income resulting from hedged foreign currency transactions recorded by the Company for the years ended December 31, 2015 , 2014 and 2013 (in thousands). The gross reclassification adjustments increased product revenue for the years ended December 31, 2015 and 2014 and decreased product revenue for the year ended December 31, 2013. Year Ended 2015 2014 2013 Gross of Tax Reclassifications $ 6,163 $ 2,748 $ (1,604 ) Net of Tax Reclassifications $ 3,698 $ 1,649 $ (962 ) The following tables show the changes in Accumulated Other Comprehensive Income by component for the years ended December 31, 2015 and 2014 (in thousands): Twelve Months Ended December 31, 2015 Unrealized Gain (Loss) on Investments Foreign Currency Translation Adjustments Unrealized Gain on Cash Flow Hedges Accumulated Other Comprehensive Income Beginning balance $ 12 $ 2,069 $ 4,422 $ 6,503 Current-period change, net of tax (20 ) (394 ) 1,553 1,139 Ending balance $ (8 ) $ 1,675 $ 5,975 $ 7,642 Income tax expense (benefit) associated with current-period change $ (13 ) $ (335 ) $ 1,005 $ 657 Twelve Months Ended December 31, 2014 Unrealized Gain on Investments Foreign Currency Translation Adjustments Unrealized Gain/(Loss) on Cash Flow Hedges Accumulated Other Comprehensive Income Beginning balance $ — $ 3,257 $ (2,404 ) $ 853 Current-period change, net of tax 12 (1,188 ) 6,826 5,650 Ending balance $ 12 $ 2,069 $ 4,422 $ 6,503 Income tax expense (benefit) associated with current-period change $ 8 $ (229 ) $ 4,593 $ 4,372

Investments

Investments	12 Months Ended
	Dec. 31, 2015
Investments, Debt and Equity Securities [Abstract]
Investments	INVESTMENTS The Company’s investments in debt securities with maturities at purchase greater than three months are classified as “available-for-sale.” Changes in fair value are reflected in other comprehensive income. The carrying amount of the Company’s investments in available-for-sale securities as of December 31, 2015 and December 31, 2014 are shown in the table below (in thousands): December 31, 2015 December 31, 2014 Short-term available-for-sale securities cost $ 14,939 $ 16,269 Short-term available-for-sale securities unrealized gain (loss) (14 ) 20 Short-term available-for-sale securities fair value $ 14,925 $ 16,289 As of December 31, 2015 , the Company’s debt securities were investment grade and carried a long-term rating of A2/A or higher.

Accounts and Other Receivables,

Accounts and Other Receivables, Net	12 Months Ended
	Dec. 31, 2015
Receivables [Abstract]
Accounts and Other Receivables, Net	ACCOUNTS AND OTHER RECEIVABLES, NET A summary of net accounts and other receivables follows (in thousands): December 31, 2015 2014 Trade accounts receivable $ 83,750 $ 126,874 Unbilled receivables 7,685 20,788 Advance billings 11,637 4,960 Short-term investment in sales-type lease 10,004 10,187 Other receivables 11,662 2,401 124,738 165,210 Allowance for doubtful accounts (19 ) (97 ) Accounts and other receivables, net $ 124,719 $ 165,113 Unbilled receivables represent amounts where the Company has recognized revenue in advance of the contractual billing terms. Advance billings represent billings made based on contractual terms for which revenue has not been recognized. As of December 31, 2015 and 2014 , accounts receivable included $44.2 million and $87.0 million , respectively, due from the U.S. Government. Of these amounts, $2.2 million and $2.1 million were unbilled as of December 31, 2015 and 2014 , respectively, based upon contractual billing arrangements with these customers. As of December 31, 2015 , one non-U.S. Government customer accounted for 18% of total accounts and other receivables. As of December 31, 2014 , no non-U.S. Government customers accounted for more than 10% of total accounts and other receivables.

Sales-Type Lease

Sales-Type Lease	12 Months Ended
	Dec. 31, 2015
Leases [Abstract]
Sales-Type Lease	SALES-TYPE LEASE As of December 31, 2015 and 2014 , the Company had a sales-type lease with one of its customers. Under the terms of the arrangement, the Company has agreed to provide a high performance computing solution to the customer for a term of four years, beginning at the customer’s acceptance of the system. The lease is designated in British Pounds and the Company has entered into certain foreign currency exchange contracts that act as an economic hedge for the foreign currency exposure associated with this arrangement. The following table shows the components of the net investment in the sales-type lease as of December 31, 2015 and 2014 (in thousands): December 31 2015 2014 Total minimum lease payments to be received $ 36,863 $ 53,134 Less: executory costs (7,434 ) (10,717 ) Net minimum lease payments receivable 29,429 42,417 Estimated residual value of leased property (unguaranteed) — 1,253 Less: unearned income (1,108 ) (2,394 ) Net investment in sales-type lease 28,321 41,276 Less: long-term investment in sales-type lease (18,317 ) (31,089 ) Investment in sales-type lease included in accounts and other receivables $ 10,004 $ 10,187 As of December 31, 2015 , minimum lease payments for each of the succeeding three fiscal years were as follows (in thousands): 2016 $ 13,405 2017 13,405 2018 10,053 Total minimum lease payments to be received $ 36,863

Inventory

Inventory	12 Months Ended
	Dec. 31, 2015
Inventory Disclosure [Abstract]
Inventory	INVENTORY A summary of inventory follows (in thousands): December 31 2015 2014 Components and subassemblies $ 20,806 $ 60,851 Work in process 43,071 46,954 Finished goods 49,778 35,827 $ 113,655 $ 143,632 As of December 31, 2015 and 2014 , $49.5 million and $35.3 million , respectively, of finished goods inventory was located at customer sites pending acceptance. At December 31, 2015 , three customers accounted for $41.7 million of finished goods inventory and at December 31, 2014 , two customers accounted for $31.2 million of finished goods inventory. During 2015 , 2014 and 2013 , the Company wrote-off $0.5 million , $2.3 million and $0.9 million , respectively, of inventory.

Property and Equipment, Net

Property and Equipment, Net	12 Months Ended
	Dec. 31, 2015
Property, Plant and Equipment [Abstract]
Property and Equipment, Net	PROPERTY AND EQUIPMENT, NET A summary of property and equipment follows (in thousands): December 31, 2015 2014 Land $ 275 $ 275 Buildings 20,612 20,409 Furniture and equipment 14,190 13,198 Computer equipment 65,957 59,785 Leasehold improvements 1,098 446 102,132 94,113 Accumulated depreciation and amortization (71,053 ) (59,320 ) Property and equipment, net $ 31,079 $ 34,793 Depreciation expense on property and equipment for 2015, 2014 and 2013 was $13.3 million , $12.8 million and $10.9 million , respectively.

Service Spares, Net

Service Spares, Net	12 Months Ended
	Dec. 31, 2015
Inventory Disclosure [Abstract]
Service Spares, Net	SERVICE SPARES, NET A summary of service spares follows (in thousands): December 31, 2015 2014 Service spares $ 15,082 $ 13,114 Accumulated depreciation (11,992 ) (11,246 ) Service spares, net $ 3,090 $ 1,868 Depreciation expense on service spares for 2015, 2014 and 2013 was $1.1 million , $1.0 million and $0.9 million , respectively.

Deferred Revenue

Deferred Revenue	12 Months Ended
	Dec. 31, 2015
Deferred Revenue Disclosure [Abstract]
Deferred Revenue	DEFERRED REVENUE A summary of deferred revenue follows (in thousands): December 31 2015 2014 Deferred product revenue $ 22,215 $ 21,152 Deferred service revenue 97,822 92,346 Total deferred revenue 120,037 113,498 Less long-term deferred revenue (33,306 ) (47,588 ) Deferred revenue in current liabilities $ 86,731 $ 65,910 As of December 31, 2015 and 2014 the U.S. Government accounted for $57.7 million and $63.8 million , respectively, of total deferred revenue. As of December 31, 2015 and 2014 , no non-U.S. Government customers accounted for more than 10% of total deferred revenue.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2015
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	COMMITMENTS AND CONTINGENCIES The Company has recorded rent expense under leases for buildings or office space, which were accounted for as operating leases, in 2015, 2014 and 2013 of $5.9 million , $5.2 million , and $5.3 million , respectively. Minimum contractual commitments as of December 31, 2015 , were as follows (in thousands): Operating Leases Development Agreements 2016 $ 5,484 $ 15,567 2017 5,149 233 2018 4,939 150 2019 4,668 25 2020 3,391 — Thereafter 12,519 — Minimum contractual commitments $ 36,150 $ 15,975 In its normal course of operations, the Company engages in development arrangements under which it hires outside engineering resources to augment its existing internal staff in order to complete research and development projects, or parts thereof. For the years ended December 31 , 2015, 2014 and 2013 , the Company incurred $14.3 million , $12.2 million and $9.3 million , respectively, for such arrangements. Litigation From time to time, the Company is subject to various legal proceedings that arise in the ordinary course of business, none of which are currently deemed to be material to the Company’s business.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Income Taxes	INCOME TAXES Income taxes are recognized for the amount of taxes payable for the current year and for the impact of deferred tax assets and liabilities, which represent consequences of events that have been recognized differently in the financial statements under GAAP than for tax purposes. Most of the Company’s deferred tax assets result from net operating loss carryforwards and research and development tax credits. As of December 31, 2015 , the Company had U.S. federal net operating loss carryforwards of approximately $76.2 million , of which approximately $47.4 million was related to stock-based income tax deductions in excess of amounts that have been recognized for financial reporting purposes. Any reduction of taxes payable for stock-based income tax deductions in excess of amounts that have been recognized for financial reporting purposes will be directly credited to shareholders’ equity. As of December 31, 2015 , the Company had federal research and development tax credit carryforwards of approximately $23.0 million . The federal net operating loss carryforwards will expire from 2019 through 2031 , and the research and development tax credits will expire from 2021 through 2035 if not utilized. Utilization of $25.6 million of the Company’s federal net operating loss carryforwards generated prior to May 10, 2001 is limited under Section 382 of the Internal Revenue Code to $4.3 million per year. As of December 31, 2015 , the Company had approximately $6.1 million of foreign net operating loss carryforwards in various jurisdictions. Most of the Company’s foreign net operating losses can be carried forward indefinitely, with certain amounts expiring from 2016 to 2025 . Income before income taxes consisted of the following (in thousands): Year Ended December 31, 2015 2014 2013 United States $ 38,362 $ 5,710 $ 17,467 International 4,415 3,987 3,562 Total $ 42,777 $ 9,697 $ 21,029 The tax provision (benefit) for income taxes related to operations consisted of the following (in thousands): Year Ended December 31, 2015 2014 2013 Current provision: Federal $ 725 $ 230 $ 484 State 1,389 (392 ) 696 Foreign 1,023 740 801 Total current provision 3,137 578 1,981 Deferred provision (benefit): Federal 12,198 (53,242 ) (13,160 ) State (52 ) (885 ) (327 ) Foreign (43 ) 923 312 Total deferred provision (benefit) 12,103 (53,204 ) (13,175 ) Total provision (benefit) for income taxes $ 15,240 $ (52,626 ) $ (11,194 ) The tax provision (benefit) differs from the amount computed by applying the federal statutory income tax rate as follows (in thousands): Year Ended December 31, 2015 2014 2013 Income tax provision at statutory rate $ 14,972 $ 3,394 $ 7,360 State taxes, net of federal benefit 897 (217 ) 369 Foreign income taxes (12 ) 284 (749 ) Share-based compensation adjustment — — (8,419 ) Deemed dividends for U.S. income tax purposes 407 492 477 Nondeductible expenses 283 337 208 Disallowed compensation 455 (116 ) 19 Research and development tax credit (1,733 ) (1,140 ) (5,736 ) Effect of change in valuation allowance on deferred tax assets (29 ) (55,660 ) (4,723 ) Effective income tax provision (benefit) $ 15,240 $ (52,626 ) $ (11,194 ) Significant components of the Company’s deferred income tax assets and liabilities follow (in thousands): December 31, 2015 2014 Current: Deferred Income Tax Assets Inventory $ 3,930 $ 5,840 Accrued compensation 1,213 681 Deferred revenue 18,372 18,186 Net operating loss carryforwards 2,636 12,981 Research and experimentation credit carryforwards 16,264 — Other 4,303 1,261 Gross current deferred tax assets 46,718 38,949 Valuation allowance (2,995 ) (2,039 ) Current deferred tax assets 43,723 36,910 Deferred Income Tax Liabilities Other (5,095 ) (837 ) Current deferred tax liabilities (5,095 ) (837 ) Net current deferred tax assets $ 38,628 $ 36,073 Long-Term: Deferred Income Tax Assets Property and equipment $ 7,510 $ 11,555 Research and experimentation credit carryforwards 9,528 24,596 Net operating loss carryforwards 14,523 21,511 Goodwill 125 203 Share-based compensation 5,976 5,000 Other 4,084 4,967 Gross long-term deferred tax assets 41,746 67,832 Valuation allowance (6,492 ) (8,099 ) Long-term deferred tax assets 35,254 59,733 Deferred Income Tax Liabilities Investment in sales-type lease, net (7,611 ) (14,321 ) Intangible assets (512 ) (1,215 ) Other (1,277 ) (2,783 ) Long-term deferred tax liabilities (9,400 ) (18,319 ) Net long-term deferred tax asset $ 25,854 $ 41,414 For the year ended December 31, 2015 , long-term deferred income tax liabilities in the amount of $0.2 million have been included in other non-current liabilities on the Company’s Consolidated Balance Sheet. The Company recorded income tax expense of $15.2 million for the year ended December 31, 2015 and an income tax benefit of $52.6 million and $11.2 million , respectively, during the years ended December 31, 2014 and 2013 . The primary reason for the difference between the income tax provision at the statutory rate and the Company’s effective income tax provision for the year ended December 31, 2015 was the result of state taxes, non-deductible expenses and other permanent items, partially offset by research and development tax credits. The tax benefit recorded by the Company during the year ended December 31, 2014 was primarily attributable to a partial reduction, in the amount of $55.7 million , of the remaining valuation allowance that was held against the Company’s U.S. deferred tax assets. The tax benefit recorded by the Company during the year ended December 31, 2013 was primarily attributable to a partial reduction, in the amount of $13.5 million , of the valuation allowance held against the Company’s U.S. deferred tax assets. The Company’s decision to partially reduce, in the amount of $55.7 million , the valuation allowance held against the Company’s U.S. deferred tax assets during the year ended December 31, 2014 was based upon an evaluation of all available positive and negative evidence, known business risks and industry trends. The Company considers its actual results over several years to have stronger weight than other more subjective indicators, including forecasts, when considering whether or not to establish or reduce a valuation allowance on deferred tax assets and believes that its ability to forecast results significantly into the future is limited due to the rapid rate of technological and competitive change in the industry in which it operates. As of December 31, 2014 the Company had generated U.S. pre-tax income in each of the last three years and cumulative U.S. pre-tax income of $184.8 million ( $51.1 million excluding the impact of the sale of the Company’s interconnect hardware development program) over the last three years. In addition to the Company’s cumulative income position, the assessment of the Company’s ability to utilize its U.S. deferred tax assets included an assessment of forecasted domestic and international earnings over a number of years, which included the impact of several major contracts that were finalized during the fourth quarter of 2014. The partial reduction, in the amount of $13.5 million , of the valuation allowance held against the Company’s U.S. deferred tax assets during the year ended December 31, 2013 was due to actual income from operations during the year ended December 31, 2013 exceeding amounts previously used in the evaluation of the realizability of the Company’s deferred tax assets at the beginning of the year and based upon an assessment of all positive and negative evidence relating to future years. The Company’s conclusion about the realizability of its deferred tax assets, and therefore the appropriateness of the valuation allowance, is reviewed quarterly and could change in future periods depending on the Company’s future assessment of all available evidence in support of the likelihood of realization of its deferred tax assets. If the Company’s conclusion about the realizability of its deferred tax assets and therefore the appropriateness of its valuation allowance changes in a future period, it could record a substantial tax provision or benefit in the Consolidated Statement of Operations when that occurs. The valuation allowance on deferred tax assets decreased by $0.7 million , $67.7 million and $4.7 million in 2015, 2014 and 2013 , respectively. The decrease in the valuation allowance for the year ended December 31, 2014 included a reduction, in the amount of $55.7 million , of the valuation allowance held against the Company’s U.S. deferred tax assets based upon an assessment of all positive and negative evidence relating to future years. The decrease in the valuation allowance for the year ended December 31, 2013 was comprised of the partial reduction of the valuation allowance of $13.5 million which was principally offset by a share-based compensation related adjustment of $8.4 million . Undistributed earnings, in the approximate amount of $9.2 million , relating to the Company’s foreign subsidiaries are considered to be permanently reinvested; accordingly, no provision for U.S. federal and state income taxes has been provided thereon. Upon repatriation of those earnings, in the form of dividends or otherwise, the Company would be subject to both U.S. income taxes (subject to an adjustment for foreign tax credits) and withholding taxes payable to the various foreign countries. Determination of the amount of unrecognized deferred U.S. income tax liability is not practicable due to the complexities associated with this hypothetical calculation. As of December 31, 2015 , the Company’s foreign subsidiaries held cash in the amount of $12.9 million . The following table summarizes changes in the amount of the Company’s unrecognized tax benefits for uncertain tax positions for the three years ended December 31, 2015, 2014 and 2013 (in thousands): Balance at December 31, 2012 $ 470 Decrease related to prior year income tax positions (268 ) Balance at December 31, 2013 $ 202 Increase related to prior year income tax positions 5,059 Increase related to current year income tax positions 369 Balance at December 31, 2014 $ 5,630 Increase related to prior year income tax positions 151 Increase related to current year income tax positions 433 Balance at December 31, 2015 $ 6,214 The balance of unrecognized tax benefits as of December 31, 2015 was $6.2 million of tax benefits that, if recognized, would affect the effective tax rate. It is not anticipated that the balance of unrecognized tax benefits will significantly change over the next twelve months. The Company or its subsidiaries file income tax returns in the U.S. federal jurisdiction and various state and foreign jurisdictions. The Company defines its major tax jurisdictions to include Australia, Germany, the United Kingdom and the United States. The Company is no longer subject to income tax examinations with respect to Australia for periods before 2010 and for periods before 2014 in Germany and the United Kingdom, respectively. With respect to the U.S. federal and various state jurisdictions the Company is no longer subject to income tax examinations with respect to periods before 2012, although in such jurisdictions net operating loss and tax credit carryforwards generated in a year are subject to examination and adjustment for at least three years following the year in which such losses or credits are actually used to offset taxable income. Estimated interest and penalties are recorded as a component of interest expense and other expense, respectively. Such amounts were not material for 2015, 2014 and 2013 .

Lines of Credit

Lines of Credit	12 Months Ended
	Dec. 31, 2015
Debt Disclosure [Abstract]
Credit Facilities	CREDIT FACILITIES As of December 31, 2015 , the Company had a $10.0 million unsecured line of credit with Wells Fargo Bank, National Association, designed to support the issuance of letters of credit and foreign currency exchange hedging transactions. The Company made no draws and had no outstanding cash borrowings on the credit facility as of December 31, 2015 . Subsequent to December 31, 2015 , the Company amended its existing credit agreement and entered into a new $50.0 million two -year line of credit agreement, effective January 7, 2016. Refer to Note 21 - Subsequent Events for further discussion on the amended agreement. In December 2015, the Company terminated its $11.0 million letter of credit facility with Silicon Valley Bank. As of December 31, 2015 , the Company had $5.8 million in USD equivalent value in outstanding letters of credit and $3.3 million in restricted cash associated with certain letters of credit to secure customer prepayments and other customer related obligations.

Shareholders' Equity

Shareholders' Equity	12 Months Ended
	Dec. 31, 2015
Share-based Compensation [Abstract]
Shareholders' Equity	SHAREHOLDERS’ EQUITY Preferred Stock: The Company has 5,000,000 shares of undesignated preferred stock authorized, and no shares of preferred stock outstanding. Common Stock: The Company has 75,000,000 authorized shares of common stock with a par value of $0.01 per share. Stock Plans: As of December 31, 2015 , the Company had one active equity incentive plan that provides shares available for option, restricted stock and restricted stock unit grants to employees, directors, executives and others. Stock Options: In determining the fair value of stock options, the Company uses the Black-Scholes option pricing model. The following key weighted average assumptions were employed in the calculation for the years ended December 31: 2015 2014 2013 Risk-free interest rate 1.31 % 1.22 % 0.98 % Expected dividend yield — % — % — % Volatility 50.55 % 52.43 % 50.45 % Expected life (in years) 4.0 4.0 4.0 Weighted average Black-Scholes value of options granted $ 11.23 $ 11.16 $ 8.22 The risk-free interest rate is based on the U.S. Treasury yield curve in effect at the time of grant. The Company does not anticipate declaring dividends in the foreseeable future. Volatility is based on historical data. The expected life of an option is based on the assumption that options will be exercised, on average, about two years after vesting occurs. The Company recognizes compensation expense for only the portion of options that are expected to vest. Therefore, management applies an estimated forfeiture rate that is derived from historical employee termination data and adjusted for expected future employee turnover rates. The estimated forfeiture rates applied to the Company’s stock option grants for the years ended December 31, 2015, 2014 and 2013 were 8.0% , 8.3% , and 10.0% , respectively. If the actual number of forfeitures differs from those estimated by management, additional adjustments to compensation expense may be required in future periods. The Company’s stock price volatility, option lives and expected forfeiture rates involve management’s best estimates at the time of such determination, which impact the fair value of the option calculated under the Black-Scholes methodology and, ultimately, the expense that will be recognized over the vesting period or requisite service period of the option. The Company typically issues stock options with a four -year vesting period (the requisite service period) and amortizes the fair value of stock options (share-based compensation cost) ratably over the requisite service period. Options to purchase shares expire no later than ten years after the date of grant. A summary of the Company’s stock option activity and related information follows: Options Weighted Average Exercise Price Weighted Average Remaining Contractual Term (Years) Outstanding at January 1, 2013 2,293,505 $ 7.31 Granted 346,360 20.65 Exercised (495,221 ) 6.38 Canceled and forfeited (66,575 ) 21.97 Outstanding at December 31, 2013 2,078,069 9.29 Granted 323,900 26.92 Exercised (411,352 ) 7.50 Canceled and forfeited (59,627 ) 18.45 Outstanding at December 31, 2014 1,930,990 12.34 Granted 307,450 27.86 Exercised (229,118 ) 9.99 Canceled and forfeited (60,847 ) 20.00 Outstanding at December 31, 2015 1,948,475 14.83 6.3 Exercisable at December 31, 2015 1,357,512 10.40 5.3 Available for grant at December 31, 2015 1,791,731 Outstanding and exercisable options by price range as of December 31, 2015 , were as follows: Outstanding Options Exercisable Options Range of Exercise Prices per Share Number Outstanding Weighted Average Remaining Life (Years) Weighted Average Exercise Price Number Exercisable Weighted Average Exercise Price $ 0.00 - $ 10.00 879,263 4.2 $ 5.67 879,179 $ 5.67 $ 10.01 - $ 20.00 412,016 6.9 $ 15.21 293,735 $ 14.51 $ 20.01 - $ 27.00 367,794 8.5 $ 25.44 115,590 $ 24.87 $ 27.01 - $ 34.52 289,402 9.0 $ 28.60 69,008 $ 28.96 $ 0.00 - $ 34.52 1,948,475 6.3 $ 14.83 1,357,512 $ 10.40 As of December 31, 2015 , there was $34.4 million of aggregate intrinsic value of outstanding stock options, including $29.9 million of aggregate intrinsic value of exercisable stock options. Intrinsic value represents the total pretax intrinsic value for all “in-the-money” options (i.e., the difference between the Company’s closing stock price on the last trading day of 2015 and the exercise price, multiplied by the number of shares of common stock underlying the stock options) that would have been received by the option holders if all option holders had exercised their options on December 31, 2015 . This amount changes, based on the fair market value of the Company’s stock. Total intrinsic value of options exercised was $5.0 million , $10.2 million , and $7.9 million for the years ended December 31, 2015, 2014 and 2013 , respectively. Restricted Stock: During 2015 , 2014 and 2013 , the Company issued an aggregate of 45,175 , 463,734 , and 755,979 shares of restricted stock, respectively, to certain directors, executives and other employees. The grant date fair value of these grants was approximately $1.4 million , $13.3 million , and $15.8 million for 2015 , 2014 and 2013 , respectively. Share-based compensation expense is recorded over the vesting period, which is generally one year for non-employee directors and four years for officers and employees of the Company. A summary of the Company’s unvested restricted stock grants and changes during the years ended December 31 is as follows: Service Vesting Restricted Shares Performance Vesting Restricted Shares Total Restricted Shares Shares Weighted Average Grant Date Fair Value Shares Weighted Shares Weighted Average Grant Date Fair Value Outstanding at January 1, 2013 1,465,738 $ 7.44 737,000 $ 12.90 2,202,738 $ 9.27 Granted 326,979 20.83 429,000 21.00 755,979 20.93 Forfeited (3,437 ) 5.92 (72,000 ) 14.88 (75,437 ) 14.48 Vested (661,580 ) 6.22 — — (661,580 ) 6.22 Outstanding at December 31, 2013 1,127,700 12.05 1,094,000 15.94 2,221,700 13.97 Granted 463,734 28.74 — — 463,734 28.74 Forfeited (134,653 ) 15.39 (277,000 ) 17.49 (411,653 ) 16.80 Vested (423,179 ) 11.14 — — (423,179 ) 11.14 Outstanding at December 31, 2014 1,033,602 19.48 817,000 15.41 1,850,602 17.68 Granted 45,175 30.44 — — 45,175 30.44 Forfeited (48,998 ) 24.00 (219,000 ) 15.60 (267,998 ) 17.14 Vested (513,336 ) 15.34 (12,500 ) 28.20 (525,836 ) 15.64 Outstanding at December 31, 2015 516,443 24.12 585,500 15.07 1,101,943 19.31 The estimated forfeiture rate applied to the Company’s service vesting restricted stock grants during the years ended December 31, 2015 and 2014 were 8.0% and 6.3% , respectively. The aggregate fair value of restricted shares vested during 2015 , 2014 and 2013 was $14.2 million , $11.9 million , and $14.0 million , respectively. The performance vesting restricted shares that remain outstanding are subject to performance measures that are currently not considered "probable" of attainment and as such, no compensation cost has been recorded for these grants. The performance vesting restricted shares are eligible to vest between 2016 and 2017 . Restricted Stock Units: During 2015 , the Company issued an aggregate of 984,850 restricted stock and performance restricted stock units with a grant date fair value of approximately $29.5 million . There were no restricted stock units issued or outstanding as of December 31, 2014 and 2013 . Restricted stock units have similar vesting characteristics as restricted stock but are not outstanding shares and do not have any voting or dividend rights. The Company records share-based compensation expense over the vesting period. At the time of vesting, a share of common stock representing each restricted stock unit vested will be issued by the Company. A summary of the Company’s unvested restricted stock unit grants and changes during the year ended December 31, 2015 is as follows: Service Vesting Restricted Stock Units Performance Vesting Restricted Stock Units Total Restricted Stock Units Units Weighted Units Weighted Units Weighted Average Grant Date Fair Value Outstanding at December 31, 2014 — $ — — $ — — $ — Granted 285,550 $ 29.78 699,300 $ 30.04 984,850 $ 29.97 Forfeited (12,500 ) $ 30.48 (66,600 ) $ 30.04 (79,100 ) $ 30.11 Vested — $ — — $ — — $ — Outstanding at December 31, 2015 273,050 $ 29.75 632,700 $ 30.04 905,750 $ 29.95 The estimated forfeiture rate applied to the Company’s service vesting restricted stock unit grants during the year ended December 31, 2015 was 8.0% . The performance vesting restricted stock units are subject to performance measures that are currently not considered "probable" of attainment and as such, no compensation cost has been recorded for these units. The performance vesting restricted stock units are eligible to vest between 2017 and 2020 . Share-based Compensation Expense: Including performance-based equity awards, the Company had $44.8 million of total unrecognized compensation cost related to unvested stock options, unvested restricted stock and unvested restricted stock units as of December 31, 2015 . Excluding the $27.8 million of unrecognized compensation cost related to unvested restricted stock and unvested restricted stock units that are subject to performance measures that are currently not considered "probable" of attainment, unrecognized compensation cost is $17.0 million . No compensation expense is recognized for unvested restricted stock or unvested restricted stock units subject to performance measures that are not considered "probable" of attainment. Unrecognized compensation cost related to unvested stock options, unvested non-performance-based restricted stock and unvested non-performance-based restricted stock units is expected to be recognized over a weighted average period of 2.7 years. The following table sets forth the gross share-based compensation cost resulting from stock options, unvested restricted stock and unvested restricted stock units that were recorded in the Company’s Consolidated Statements of Operations for the years ended December 31 (in thousands): 2015 2014 2013 Cost of product revenue $ 254 $ 229 $ 135 Cost of service revenue 276 255 229 Research and development 3,770 2,721 1,480 Sales and marketing 3,047 3,152 2,230 General and administrative 4,006 4,007 3,165 Total share-based compensation expense $ 11,353 $ 10,364 $ 7,239 Employee Stock Purchase Plan (ESPP): Under the Company’s non-compensatory employee stock purchase plan, the maximum number of shares of the Company’s common stock that employees could acquire under the ESPP is 1,750,000 shares. Eligible employees are permitted to acquire shares of the Company’s common stock through payroll deductions not exceeding 15% of base wages. The purchase price per share under the ESPP is 95% of the closing market price on the fourth business day after the end of each offering period. As of December 31, 2015, 2014 and 2013 , an aggregate of 1,070,343 , 1,043,228 and 1,022,610 shares, respectively, had been issued under the ESPP.

Benefit Plans

Benefit Plans	12 Months Ended
	Dec. 31, 2015
Compensation and Retirement Disclosure [Abstract]
Benefit Plans	BENEFIT PLANS 401(k) Plan For the three years ended December 31, 2015 , the Company’s retirement plan covered substantially all U.S. employees and provided for voluntary salary deferral contributions on a pre-tax basis in accordance with Section 401(k) of the Internal Revenue Code of 1986, as amended. The Company matches a portion of employee contributions. The 2015, 2014 and 2013 Company match expense was $2.6 million , $1.6 million and $1.2 million , respectively. Pension Plan The Company’s German subsidiary maintains a defined benefit pension plan. At December 31, 2015 , the excess of plan assets over the projected benefit obligation of $2.1 million was $0.2 million . At December 31, 2014 , the excess of plan assets over the projected benefit obligation of $2.3 million was $0.2 million . Plan assets are invested in insurance policies payable to employees. Net pension expense was not material for any period. Contributions to the plan are not expected to be significant to the financial position of the Company.

Segment Information

Segment Information	12 Months Ended
	Dec. 31, 2015
Segment Reporting [Abstract]
Segment Information	SEGMENT INFORMATION The Company has the following reportable segments: Supercomputing, Storage and Data Management, Maintenance and Support, and Engineering Services and Other. The Company’s reportable segments represent components of the Company for which separate financial information is available that is utilized on a regular basis by the Chief Executive Officer, who is the Chief Operating Decision Maker, in determining how to allocate the Company’s resources and evaluate performance. The segments are determined based on several factors, including the Company’s internal operating structure, the manner in which the Company’s operations are managed, client base, similar economic characteristics and the availability of separate financial information. Supercomputing Supercomputing includes a suite of highly advanced, tightly integrated and cluster supercomputer systems which are used by large research and engineering centers in universities, government laboratories, and commercial institutions. Supercomputing also includes the ongoing maintenance of these systems as well as system analysts. Storage and Data Management Storage and Data Management offers the Cray Sonexion and Tiered Adaptive Storage solution as well as other third-party storage products and their ongoing maintenance as well as system analysts. Maintenance and Support Maintenance and Support provides ongoing maintenance of Cray supercomputers, big data storage and analytics systems, as well as system analysts. Engineering Services and Other Included within Engineering Services and Other is the Company’s analytics business and Custom Engineering. The following table presents revenues and gross margin for the Company’s operating segments for the years ended December 31 (in thousands): 2015 2014 2013 Revenue: Supercomputing $ 581,733 $ 459,729 $ 434,133 Storage and Data Management 112,862 84,412 76,955 Maintenance and Support 97,091 86,573 77,817 Engineering Services and Other 30,094 17,465 14,661 Elimination of inter-segment revenue (97,091 ) (86,573 ) (77,817 ) Total revenue $ 724,689 $ 561,606 $ 525,749 Gross Profit: Supercomputing $ 177,048 $ 146,565 $ 143,440 Storage and Data Management 37,181 31,572 31,403 Maintenance and Support 41,487 38,819 38,476 Engineering Services and Other 11,454 6,277 9,483 Elimination of inter-segment gross profit (41,487 ) (38,819 ) (38,476 ) Total gross profit $ 225,683 $ 184,414 $ 184,326 Revenue and cost of revenue is the only discrete financial information the Company prepares for its segments. Other financial results or assets are not separated by segment. The Company’s geographic operations outside the United States include sales and service offices in Europe and the Middle East, South America, Asia Pacific and Canada. The following data represents the Company’s revenue and long-lived assets for the United States and all other countries (in thousands): United States All Other Countries Total For the year ended December 31, 2015: Product revenue $ 373,494 $ 227,800 $ 601,294 Service revenue $ 88,956 $ 34,439 $ 123,395 Long-lived assets $ 55,227 $ 23,731 $ 78,958 For the year ended December 31, 2014: Product revenue $ 253,930 $ 206,818 $ 460,748 Service revenue $ 72,434 $ 28,424 $ 100,858 Long-lived assets $ 58,868 $ 36,792 $ 95,660 For the year ended December 31, 2013: Product revenue $ 297,583 $ 138,747 $ 436,330 Service revenue $ 62,072 $ 27,347 $ 89,419 Long-lived assets $ 58,910 $ 6,146 $ 65,056 Long-lived assets as of December 31, 2015 and 2014 , included the $18.3 million and $31.1 million , respectively, long-term investment in sales-type lease which was held by the Company’s United Kingdom subsidiary. Revenue attributed to foreign countries is derived from sales to customers located outside the United States. Revenue derived from the U.S. Government totaled approximately $338.5 million , $272.0 million and $266.1 million in 2015, 2014 and 2013 , respectively. In 2015 and 2014 , no non-U.S. Government customers accounted for more than 10% of total revenue. In 2013 , one non-U.S. Government customer accounted for an aggregate of approximately 11% of total revenue. In general, concentrations of revenue by customer encompass all segments. In 2015 and 2013 , no foreign country accounted for more than 10% of total revenue. In 2014 , the United Kingdom and Germany accounted for a combined 23% of total revenue.

Research and Development

Research and Development	12 Months Ended
	Dec. 31, 2015
Research and Development [Abstract]
Research and Development	RESEARCH AND DEVELOPMENT The detail for the Company’s net research and development costs for the years ended December 31 follows (in thousands): 2015 2014 2013 Gross research and development expenses $ 126,060 $ 104,797 $ 92,469 Less: Amounts included in cost of revenue (16,515 ) (7,713 ) (3,741 ) Less: Reimbursed research and development (excludes amounts in revenue) (12,982 ) (3,036 ) (1,000 ) Net research and development expenses $ 96,563 $ 94,048 $ 87,728

Interest Income (Expense)

Interest Income (Expense)	12 Months Ended
	Dec. 31, 2015
Other Income and Expenses [Abstract]
Interest Income (Expense)	INTEREST INCOME (EXPENSE) The detail of interest income (expense) for the years ended December 31 follows (in thousands): 2015 2014 2013 Interest income $ 1,465 $ 643 $ 894 Interest expense (57 ) (137 ) (137 ) Net interest income $ 1,408 $ 506 $ 757 Interest income is earned by the Company on cash and cash equivalents, investment balances and the investment in sales-type lease.

Quarterly Data (Unaudited)

Quarterly Data (Unaudited)	12 Months Ended
	Dec. 31, 2015
Quarterly Financial Information Disclosure [Abstract]
Quarterly Data (Unaudited)	QUARTERLY DATA (UNAUDITED) The following table presents unaudited quarterly financial information for the two years ended December 31, 2015 . In the opinion of management, this information contains all adjustments, consisting only of normal recurring adjustments, necessary for a fair presentation thereof. The operating results are not necessarily indicative of results for any future periods. Quarter-to-quarter comparisons should not be relied upon as indicators of future performance. The Company’s business is driven by a few significant contracts and, as a result, the Company’s operating results are subject to very large quarterly fluctuations. The Company’s earnings per share for the full year may not equal the sum of the four quarterly earnings per share amounts because of common share activity during the year. (In thousands, except per share data) 2015 2014 For the Quarter Ended 3/31 6/30 9/30 12/31 3/31 6/30 9/30 12/31 Revenue $ 79,644 $ 186,161 $ 191,413 $ 267,471 $ 55,110 $ 85,147 $ 159,406 $ 261,943 Cost of revenue 55,608 136,576 125,531 181,291 37,173 56,143 110,876 173,000 Gross profit 24,036 49,585 65,882 86,180 17,937 29,004 48,530 88,943 Research and development, net 22,187 20,106 24,989 29,281 22,621 24,189 22,503 24,735 Sales and marketing 12,552 13,412 16,132 18,054 11,776 13,259 14,808 17,942 General and administrative 6,140 6,435 6,729 8,662 5,413 5,316 5,813 6,839 Net income (loss) (1) (9,394 ) 5,781 10,855 20,295 (12,938 ) (6,748 ) 7,371 74,638 Net income (loss) per common share, basic $ (0.24 ) $ 0.15 $ 0.28 $ 0.51 $ (0.34 ) $ (0.18 ) $ 0.19 $ 1.92 Net income (loss) per common share, diluted $ (0.24 ) $ 0.14 $ 0.27 $ 0.50 $ (0.34 ) $ (0.18 ) $ 0.18 $ 1.84 (1) The fourth quarter of 2014 includes the impact of the reduction of substantially all of the valuation allowance held against the Company’s U.S. deferred tax assets.

Subsequent Events

Subsequent Events	12 Months Ended
	Dec. 31, 2015
Subsequent Events [Abstract]
Subsequent Events	SUBSEQUENT EVENTS On January 7, 2016, the Company entered into an Amended and Restated Credit Agreement, or Amended Credit Agreement, with Wells Fargo Bank, National Association which provides a revolving line of credit, or Credit Facility, through December 1, 2017, for up to $50.0 million to be used for general corporate purposes, including working capital requirements and capital expenditures. The Credit Facility will also support the issuance of letters of credit. The Credit Facility is secured by a first priority lien in all of the Company’s accounts receivable and other rights to payment, general intangibles, inventory and equipment. Borrowings under the Credit Facility bear interest at either a fluctuating rate equal to the daily one month LIBOR rate plus a margin of 1.25% or a fixed interest rate for one, three or six months equal to the LIBOR rate for the applicable period plus a margin of 1.25% . The Company is also required to pay the lender customary letter of credit fees, and a commitment fee of 0.18% per annum in respect of the unutilized commitment amount under the Credit Facility. The Credit Facility requires that the Company maintain certain financial ratios. The Amended Credit Agreement restates and replaces the Restated Credit Agreement with Wells Fargo Bank, National Association dated as of October 1, 2012, as amended, which provided a $10.0 million line of credit to secure letters of credit and foreign currency exchange hedging transactions.

Schedule II - Valuation and Qua

Schedule II - Valuation and Qualifying Accounts	12 Months Ended
	Dec. 31, 2015
Valuation and Qualifying Accounts [Abstract]
Schedule of Valuation and Qualifying Accounts	Schedule II — Valuation and Qualifying Accounts(1) December 31, 2015 (In Thousands) Description Balance at Beginning of Period Charge/(Benefit) to Expense Deductions (2) Balance at End of Period Year ended December 31, 2013: Allowance for doubtful accounts $ 5 $ 179 $ (27 ) $ 157 Year ended December 31, 2014: Allowance for doubtful accounts $ 157 $ 22 $ (82 ) $ 97 Year ended December 31, 2015: Allowance for doubtful accounts $ 97 $ — $ (78 ) $ 19 (1) The Company does not have any warranty liabilities. (2) Deductions represent uncollectible accounts written off, net of recoveries.

Summary of Significant Accoun30

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2015
Accounting Policies [Abstract]
Principles of Consolidation	Principles of Consolidation The consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries. All material intercompany balances and transactions have been eliminated.
Reclassifications	Reclassifications Certain prior year amounts have been reclassified to conform with the current year presentation. There has been no impact on previously reported net income or shareholders’ equity from such reclassifications.
Use of Estimates	Use of Estimates The preparation of financial statements in accordance with GAAP requires management to make estimates and assumptions that affect the amounts reported in the Company’s consolidated financial statements and accompanying notes. Actual results could differ materially from those estimates.
Cash, Cash Equivalents and Restricted Cash	Cash, Cash Equivalents and Restricted Cash Cash and cash equivalents consist of highly liquid financial instruments that are readily convertible to cash and have maturities of three months or less at the time of acquisition. The Company maintains cash and cash equivalent balances with financial institutions that exceed federally insured limits. As of December 31, 2015 and 2014 , the Company had $1.7 million and $16.9 million , respectively, in short-term restricted cash. As of December 31, 2015 , the Company had $1.7 million in long-term restricted cash. The restricted cash is associated with certain letters of credit outstanding to secure customer prepayments.
Investments	Investments The Company’s investments consist primarily of commercial paper, corporate debt, and other debt securities. Debt securities are classified as available-for-sale and are reported at fair value with unrealized gains and losses, net of applicable taxes, recorded in accumulated other comprehensive income, a component of shareholders’ equity. The realized gains and losses for available-for-sale securities are included in other income and expense in the Consolidated Statements of Operations. Realized gains and losses are calculated based on the specific identification method. The Company monitors its investment portfolio for impairment on a periodic basis. When the carrying value of an investment in debt securities exceeds its fair value and the decline in value is determined to be an other-than-temporary decline, and when the Company does not intend to sell the debt security and it is not more likely than not that the Company will be required to sell the debt securities prior to recovery of its amortized cost basis, the Company records an impairment charge in the amount of the credit loss and the balance, if any, to other comprehensive income (loss). Investments that mature between three months and one year from the purchase date are initially classified as short-term investments in the Consolidated Balance Sheet. Investments that mature beyond one year from the purchase date are initially classified as long-term investments in the Consolidated Balance Sheet. The Company’s investments in debt securities with maturities at purchase greater than three months are classified as “available-for-sale.” Changes in fair value are reflected in other comprehensive income.
Foreign Currency Derivatives	Foreign Currency Derivatives The Company uses foreign currency exchange contracts to hedge certain foreign currency exposures. Foreign currency exchange contracts are cash flow hedges of the Company’s foreign currency exposures on certain revenue contracts and are recorded at the contract’s fair value. Most of the Company’s foreign currency exchange contracts are designated as cash flow hedges for the purposes of hedge accounting treatment and any gains or losses on the effective portion of the foreign currency exchange contract is initially reported in “Accumulated other comprehensive income,” a component of shareholders’ equity, with a corresponding asset or liability recorded based on the fair value of the foreign currency exchange contract. When the hedged transaction is recognized, any unrecognized gains or losses on the hedged transaction are reclassified into results of operations in the same period. Any hedge ineffectiveness is recorded to operations in the current period. The Company measures hedge effectiveness by comparing changes in fair values of the foreign currency exchange contract and expected cash flows based on changes in the spot prices of the underlying currencies. Cash flows from foreign currency exchange contracts accounted for as cash flow hedges are classified in the same category as the cash flows from the items being hedged. Unrealized gains or losses related to foreign currency exchange contracts that are not designated as cash flow hedges for the purposes of hedge accounting treatment are recorded in the Consolidated Statement of Operations and are generally offset by foreign currency adjustments on related receivables. The Company does not use derivative financial instruments for speculative purposes.
Concentration of Credit Risk	Concentration of Credit Risk Financial instruments that potentially subject the Company to significant concentrations of credit risk consist primarily of cash and cash equivalents, available-for-sale investments, accounts receivable, short-term and long-term restricted cash and foreign currency exchange contracts. The Company maintains cash and cash equivalents, available-for-sale securities and foreign currency exchange contracts with various financial institutions. As part of its risk management process, the Company performs periodic evaluations of the relative credit standing of the financial institutions. The Company has not sustained any credit losses from instruments held at financial institutions. The Company utilizes foreign currency exchange contracts to protect against the effects of foreign currency fluctuations. Such contracts involve the risk of non-performance by the counterparty, which could result in a material loss. The Company currently derives a significant portion of its revenue from sales of products and services to the U.S. Government. See Note 17 — Segment Information for additional information. Given the type of customers, the Company does not believe its accounts receivable represent significant credit risk. The Company currently has a long-term investment in a sales-type lease it entered into with one of its customers. See Note 7 — Sales-type Lease for additional information. Given the credit standing of the customer, the Company does not believe that this investment represents a significant credit risk.
Other Concentration	Other Concentration The Company obtains certain components from single-source suppliers due to technology, availability, price, quality or other considerations. The loss of a single-source supplier, the single-source supplier’s inability to deliver the required components or intellectual property due to natural disaster or other reasons, the deterioration of the relationship with a single-source supplier, or any unilateral modification of contract terms under which the Company is supplied components by a single-source supplier could have a significant adverse effect on the Company’s revenue and gross margins.
Accounts Receivable	Accounts Receivable Accounts receivable are stated at principal amounts and are primarily comprised of amounts contractually due from customers for products and services and amounts due from government research and development contracts. The Company provides an allowance for doubtful accounts based on an evaluation of customer past due account balances. In determining whether to record an allowance for a specific customer, the Company considers a number of factors, including prior payment history and financial information for the customer.
Fair Values of Financial Instruments	Fair Values of Financial Instruments The Company measures certain financial assets and liabilities at fair value based on the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants. The Company’s financial instruments primarily consist of debt securities, time deposits, money market funds, and foreign currency derivatives. See Note 3 — Fair Value Measurement for a further discussion on fair value of financial instruments.
Inventories	Inventories Inventories are valued at the lower of cost or market, with cost computed on a first-in, first-out basis (FIFO). The Company regularly evaluates the technological usefulness and anticipated future demand for various inventory components and the expected use of the inventory. When the Company determines it is not likely the cost of inventory items will be recovered through future sales, the Company writes-down the related inventory to its estimated market value. In connection with certain of its sales agreements, the Company may receive used equipment from a customer. This inventory generally will be recorded at no value based on the expectation that the Company will not be able to resell or otherwise use the equipment. In the event that the Company has a specific contractual plan for resale at the date the inventory is acquired, the inventory is recorded at its estimated fair value.
Property and Equipment and Intangible Assets	Property and Equipment and Intangible Assets, Net Property and equipment are recorded at cost less accumulated depreciation and amortization. Additions and improvements are capitalized and maintenance and repairs are expensed as incurred. Depreciation is calculated on a straight-line basis over the estimated useful lives of the related assets, ranging from eighteen months to seven years for furniture and fixtures, three years for computer equipment, and eight to twenty-five years for buildings and land improvements. Leasehold improvements are depreciated over the life of the lease or asset, whichever is shorter. The Company amortizes purchased intangible assets with finite lives using the straight-line method over the estimated economic lives of the assets, ranging from two to ten years .
Service Spares	Service Spares Service spares are valued at the lower of cost or market and represent inventory used to support service and maintenance agreements with customers. As inventory is utilized, replaced items are returned to the Company and are either repaired or scrapped. Costs incurred to repair inventory to a usable state are charged to expense as incurred. Service spares are recorded at cost and amortized over the estimated service life of the related product platform (generally four years ).
Impairment of Long-Lived Assets and Intangibles	Impairment of Long-Lived Assets and Intangibles The Company evaluates property, plant and equipment and intangible assets with finite lives for impairment whenever events or changes in circumstances indicate the carrying value of an asset may not be recoverable. The Company assesses the recoverability of the assets based on the undiscounted future cash flow the assets are expected to generate and recognizes an impairment loss when estimated undiscounted future cash flow expected to result from the use of the asset plus net proceeds expected from disposition of the asset, if any, are less than the carrying value of the asset. When the Company identifies an impairment, the carrying value of the asset is reduced to its estimated fair value based on a discounted cash flow approach or, when available and appropriate, to comparable market values.
Goodwill	Goodwill Goodwill is not amortized but is tested for impairment at least annually. The Company reviews goodwill for impairment annually at the beginning of its fourth fiscal quarter and whenever events or changes in circumstances indicate the carrying value of the asset may not be recoverable. The goodwill impairment test consists of a two-step process, if necessary. However, the Company first assesses qualitative factors to determine whether it is more likely than not that the fair value of a reporting unit is less than its carrying amount as a basis for determining whether it is necessary to perform the two-step goodwill impairment test described in ASC Topic 350. The more likely than not threshold is defined as having a likelihood of more than 50 percent. If, after assessing the totality of events or circumstances, the Company determines that it is not more likely than not that the fair value of a reporting unit is less than its carrying amount, then performing the two-step impairment test is unnecessary and goodwill is considered to be unimpaired. However, if based on the qualitative assessment the Company concludes that it is more likely than not that the fair value of a reporting unit is less than its carrying amount, the Company will proceed with performing the two-step process. In step one, the Company determines the fair value of each reporting unit and compares it to its carrying value. If the fair value of the reporting unit exceeds the carrying value of the net assets assigned to that unit, goodwill is not impaired and no further testing is performed. If the carrying value of the net assets assigned to the reporting unit exceeds the fair value of the reporting unit, then the Company must perform the second step of the impairment test in order to determine the implied fair value of the reporting unit’s goodwill. If the carrying value of a reporting unit’s goodwill exceeds its implied fair value, the Company records an impairment loss equal to the difference. The Company performed its qualitative assessment during the fourth fiscal quarter of 2015 and concluded that it was more likely than not that the fair values of its reporting units were greater than their carrying amounts. After reaching this conclusion, the two-step impairment test was unnecessary and no further testing was performed. The qualitative factors that were considered included, but were not limited to, general economic conditions, outlook for the HPC and big data markets, recent and forecasted financial performance and the price of the Company’s common stock.
Business Combinations	Business Combinations The Company accounts for business combinations using the acquisition method of accounting and allocates the purchase price to the tangible and intangible assets acquired and the liabilities assumed based upon their estimated fair values at the acquisition date. The difference between the purchase price and the fair value of the net assets acquired is recorded as goodwill. The Company uses estimates and assumptions to accurately value assets acquired and liabilities assumed at the acquisition date. During the measurement period, which may be up to one year from the acquisition date, any refinements made to the fair value of the assets and liabilities assumed are recorded with retrospective effect. The fair values of intangible assets acquired are estimated using a discounted cash flow approach with Level 3 inputs. Under this method, an intangible asset’s fair value is equal to the present value of the incremental after-tax cash flows (excess earnings) attributable solely to the intangible asset over its remaining useful life. To calculate fair value, the Company uses risk-adjusted cash flows discounted at rates considered appropriate given the inherent risks associated with each type of asset. The Company believes the level and timing of cash flows appropriately reflects market participant assumptions.
Revenue Recognition	Revenue Recognition The Company recognizes revenue, including transactions under sales-type leases, when it is realized or realizable and earned. The Company considers revenue realized or realizable and earned when it has persuasive evidence of an arrangement, delivery has occurred, the sales price is fixed or determinable, and collectibility is reasonably assured. Delivery does not occur until the products have been shipped or services provided to the customer, risk of loss has transferred to the customer, and, where applicable, a customer acceptance has been obtained. The sales price is not considered to be fixed or determinable until all material contingencies related to the sales have been resolved. The Company records revenue in the Consolidated Statements of Operations net of any sales, use, value added or certain excise taxes imposed by governmental authorities on specific sales transactions. In addition to the aforementioned general policy, the following are the Company’s statements of policy with regard to multiple-element arrangements and specific revenue recognition policies for each major category of revenue. Multiple-Element Arrangements. The Company commonly enters into revenue arrangements that include multiple deliverables of its product and service offerings due to the needs of its customers. Products may be delivered in phases over time periods which can be as long as five years . Maintenance services generally begin upon acceptance of the first equipment delivery and future deliveries of equipment generally have an associated maintenance period. The Company considers the maintenance period to commence upon acceptance of the product or installation in situations where a formal acceptance is not required, which may include a warranty period and accordingly allocates a portion of the arrangement consideration as a separate deliverable which is recognized as service revenue over the entire service period. Other services such as training and engineering services can be delivered as a discrete delivery or over the term of the contract. A multiple-element arrangement is separated into more than one unit of accounting if the following criteria are met: • The delivered item(s) has value to the customer on a standalone basis; and • If the arrangement includes a general right of return relative to the delivered item(s), delivery or performance of the undelivered item(s) is considered probable and substantially in the control of the Company. If these criteria are met for each element, the arrangement consideration is allocated to the separate units of accounting based on each unit’s relative selling price. If these criteria are not met, the arrangement is accounted for as one unit of accounting which would result in revenue being recognized ratably over the contract term or being deferred until the earlier of when such criteria are met or when the last undelivered element is delivered. The Company follows a selling price hierarchy in determining the best estimate of the selling price of each deliverable. Certain products and services are sold separately in standalone arrangements for which the Company is sometimes able to determine vendor specific objective evidence, or VSOE. The Company determines VSOE based on normal pricing and discounting practices for the product or service when sold separately. When the Company is not able to establish VSOE for all deliverables in an arrangement with multiple elements, the Company attempts to establish the selling price of each remaining element based on third-party evidence, or TPE. The Company’s inability to establish VSOE is often due to a relatively small sample of customer contracts that differ in system size and contract terms which can be due to infrequently selling each element separately, not pricing products within a narrow range, or only having a limited sales history, such as in the case of certain advanced and emerging technologies. TPE is determined based on the Company’s prices or competitor prices for similar deliverables when sold separately. However, the Company is often unable to determine TPE, as the Company’s offerings usually contain a significant level of customization and differentiation from those of competitors and the Company is often unable to reliably determine what similar competitor products’ selling prices are on a standalone basis. When the Company is unable to establish selling price using VSOE or TPE, the Company uses estimated selling price, or ESP, in its allocation of arrangement consideration. The objective of ESP is to determine the price at which the Company would transact a sale if the product or service were sold on a standalone basis. In determining ESP, the Company uses the cost to provide the product or service plus a margin, or considers other factors. When using cost plus a margin, the Company considers the total cost of the product or service, including customer-specific and geographic factors. The Company also considers the historical margins of the product or service on previous contracts and several factors including any changes to pricing methodologies, competitiveness of products and services and cost drivers that would cause future margins to differ from historical margins. Products . The Company most often recognizes revenue from sales of products upon customer acceptance of the system. Where formal acceptance is not required, the Company recognizes revenue upon delivery or installation. When the product is part of a multiple element arrangement, the Company allocates a portion of the arrangement consideration to product revenue based on estimates of selling price. Services . Maintenance services are provided under separate maintenance contracts with customers. These contracts generally provide for maintenance services for one year , although some are for multi-year periods, often with prepayments for the term of the contract. The Company considers the maintenance period to commence upon acceptance of the product or installation in situations where a formal acceptance is not required, which may include a warranty period. When service is part of a multiple element arrangement, the Company allocates a portion of the arrangement consideration to maintenance service revenue based on estimates of selling price. Maintenance contracts that are billed in advance of revenue recognition are recorded as deferred revenue. Maintenance revenue is recognized ratably over the term of the maintenance contract. Revenue from engineering services is recognized as services are performed. Project Revenue . Revenue from design and build contracts is recognized under the percentage-of-completion, or POC, method. Under the POC method, revenue is recognized based on the costs incurred to date as a percentage of the total estimated costs to fulfill the contract. If circumstances arise that change the original estimates of revenues, costs, or extent of progress toward completion, revisions to the estimates are made. These revisions may result in increases or decreases in estimated revenues or costs, and such revisions are recorded in income in the period in which the circumstances that gave rise to the revision become known by management. The Company performs ongoing profitability analyses of its contracts accounted for under the POC method in order to determine whether the latest estimates of revenue, costs and extent of progress require updating. If at any time these estimates indicate that the contract will be unprofitable, the entire estimated loss for the remainder of the contract is recorded immediately. The Company records revenue from certain research and development contracts which include milestones using the milestone method if the milestones are determined to be substantive. A milestone is considered to be substantive if management believes there is substantive uncertainty that it will be achieved and the milestone consideration meets all of the following criteria: • It is commensurate with either of the following: • The Company’s performance to achieve the milestone; or • The enhancement of value of the delivered item or items as a result of a specific outcome resulting from the Company’s performance to achieve the milestone. • It relates solely to past performance. • It is reasonable relative to all of the deliverables and payment terms (including other potential milestone consideration) within the arrangement. The individual milestones are determined to be substantive or non-substantive in their entirety and milestone consideration is not bifurcated. Revenue from projects is classified as Product Revenue or Service Revenue, based on the nature of the work performed. Nonmonetary Transactions . The Company values and records nonmonetary transactions at the fair value of the asset surrendered unless the fair value of the asset received is more clearly evident, in which case the fair value of the asset received is used.
Sales-type lease	Sales-type leases When the Company leases a system to a customer, the accounting involves specific determinations, which often involve complex provisions and significant judgments. The four criteria of the accounting standard that the Company uses in the determination of whether a lease is a sales-type lease or an operating lease are: (a) a review of the lease term to determine if it is equal to or greater than 75% of the economic life of the system; (b) a review of the minimum lease payments to determine if they are equal to or greater than 90% of the fair value of the system; (c) a determination of whether or not the lease transfers ownership to the lessee at the end of the lease term; and (d) a determination of whether or not the lease contains a bargain purchase option. If the lease transaction meets one of the four criteria, then it is recorded as a sales-type lease; otherwise it is an operating lease. Additionally, the Company assesses whether collectibility of the lease payments is reasonably assured and whether there are any significant uncertainties related to costs that it has yet to incur with respect to the lease. The Company considers the economic lives of most of its products to range from three to four years. There is no significant after-market for the Company’s used products and the Company believes that the economic lives are representative of the periods during which its products are expected to be economically usable, with normal service, for the purposes for which they were intended. Residual values are not significant. The discount rate implicit in the sales-type lease is used to calculate the present value of minimum lease payments, which the Company records as a lease receivable. The minimum lease payment consists of the gross lease payments net of executory costs and contingencies, if any. While revenue is recognized at inception of the lease, the cash flow from the sales-type lease occurs over the course of the lease, which results in interest income. Unearned interest income is recorded at inception of the lease and amortized over the lease term using the effective interest method.
Foreign Currency Transaction	Foreign Currency Translation The Company uses the U.S. dollar predominantly as its functional currency. Assets and liabilities of foreign subsidiaries that have a functional currency denominated in non-U.S. dollars are translated into U.S. dollars at year-end exchange rates, and revenue and expenses of these foreign subsidiaries are translated at average rates prevailing during the year. Translation adjustments are included in “Accumulated other comprehensive income,” a separate component of shareholders’ equity. Transaction gains and losses arising from transactions denominated in a currency other than the functional currency of the entity involved are included in “Other (income) expense, net” in the accompanying Consolidated Statements of Operations. Net transaction gains were $1.6 million and $2.1 million for 2015 and 2014 , respectively, and net transaction losses were $1.3 million for 2013 .
Research and Development	Research and Development Research and development expenses include costs incurred in the development and production of hardware and software, costs incurred to enhance and support existing product features, costs incurred to support and improve development processes, and costs related to future product development. Research and development costs are expensed as incurred, and may be offset by co-funding from third parties. The Company may also enter into arrangements whereby it makes advance, non-refundable payments to a vendor to perform certain research and development services. These payments are deferred and recognized over the vendor’s estimated performance period. Amounts to be received under co-funding arrangements with the U.S. government or others are based on either contractual milestones or costs incurred. These co-funding milestone payments are recognized in operations as performance is estimated to be completed and are measured as milestone achievements occur or as costs are incurred. These estimates are reviewed on a periodic basis and are subject to change, including in the near term. If an estimate is changed, net research and development expense could be impacted significantly. The Company does not record a receivable from the U.S. government prior to completing the requirements necessary to bill for a milestone or cost reimbursement. Funding from the U.S. government is subject to certain budget restrictions and milestones may be subject to completion risk, and as a result, there may be periods in which research and development costs are expensed as incurred for which no reimbursement is recorded, as milestones have not been completed or the U.S. government has not funded an agreement. Accordingly, there can be substantial variability in the amount of net research and development expenses from quarter to quarter and year to year. The Company classifies amounts to be received from funded research and development projects as either revenue or a reduction to research and development expense based on the specific facts and circumstances of the contractual arrangement, considering total costs expected to be incurred compared to total expected funding and the nature of the research and development contractual arrangement. In the event that a particular arrangement is determined to represent revenue, the corresponding research and development costs are classified as cost of revenue.
Income Taxes	Income Taxes Deferred tax assets and liabilities are determined based on differences between financial reporting and tax bases of assets and liabilities and operating loss and tax credit carryforwards and are measured using the enacted tax rates and laws that will be in effect when the differences and carryforwards are expected to be recovered or settled. A valuation allowance for deferred tax assets is provided when the Company estimates that it is more likely than not that all or a portion of the deferred tax assets may not be realized through future operations. This assessment is based upon consideration of available positive and negative evidence, which includes, among other things, recent results of operations and expected future profitability. The Company considers its actual historical results over several years to have stronger weight than other more subjective indicators, including forecasts, when considering whether to establish or reduce a valuation allowance on deferred tax assets. The Company recognizes the income tax benefit from a tax position only if it is more likely than not that the tax position will be sustained on examination by the applicable taxing authorities, based on the technical merits of the Company’s position. The tax benefit recognized in the financial statements from such a position is measured based on the largest benefit that has a greater than fifty percent likelihood of being realized upon ultimate settlement. Estimated interest and penalties are recorded as a component of interest expense and other expense, respectively. As of December 31, 2015 , the Company had approximately $74.0 million of net deferred tax assets before application of a valuation allowance. As of December 31, 2015 , net deferred tax assets after reduction by the valuation allowance of $9.5 million were $64.5 million . During the year ended December 31, 2014, the Company reduced substantially all of the remaining valuation allowance held against the Company’s U.S. deferred tax assets. The Company continues to provide a valuation allowance against specific U.S. deferred tax assets and a valuation allowance against deferred tax assets arising in a limited number of foreign jurisdictions as the realization of such assets is not considered to be more likely than not at this time. In a future period, the Company’s assessment of the realizability of its deferred tax assets and therefore the appropriateness of the valuation allowance could change based on an assessment of all available evidence, both positive and negative in that future period. If the Company’s conclusion about the realizability of its deferred tax assets and therefore the appropriateness of the valuation allowance changes in a future period, the Company could record a substantial tax provision or benefit in its Consolidated Statement of Operations when that occurs.
Share-based Compensation	Share-Based Compensation The Company measures compensation cost for share-based payment awards at fair value and recognizes it as compensation expense over the service period for awards expected to vest. Share-based compensation expense is recognized for all share-based payment awards, net of an estimated forfeiture rate. Compensation cost is only recognized for those shares expected to vest on a straight-line basis over the requisite service period of the award. Determining the appropriate fair value model and calculating the fair value of share-based payment awards requires subjective assumptions, including the expected life of the share-based payment awards and stock price volatility. The Company utilizes the Black-Scholes options pricing model to value the stock options granted under its options plans. In this model, the assumptions utilized relate to stock price volatility, stock option term and forfeiture rates that are based upon both historical factors as well as management’s judgment. The fair value of restricted stock and restricted stock units is determined based on the number of shares or units granted and the quoted price of the Company’s common stock at the date of grant. The Company grants performance vesting restricted stock and performance vesting restricted stock units to executives as one of the ways to align compensation with shareholder interests. Vesting of these awards is contingent upon achievement of certain performance conditions. Compensation expense for these awards is only recorded when vesting is deemed to be "probable". Awards are evaluated for probability of vesting each reporting period.
Shipping and Handling Costs	Shipping and Handling Costs Costs related to shipping and handling are included in “Cost of product revenue” and “Cost of service revenue” in the accompanying Consolidated Statements of Operations.
Advertising Costs	Advertising Costs Sales and marketing expenses in the accompanying Consolidated Statements of Operations included advertising expenses of $2.3 million , $2.9 million , and $2.2 million in 2015 , 2014 , and 2013 , respectively. The Company incurs advertising costs for representation at certain trade shows, promotional events and sales lead generation, as well as design and printing costs for promotional materials. The Company expenses all advertising costs as incurred.
Earnings Per Share	Earnings Per Share, or EPS Basic EPS is computed by dividing net income available to common shareholders by the weighted average number of common shares, excluding unvested restricted stock outstanding during the period. Diluted EPS is computed by dividing net income available to common shareholders by the weighted average number of common and potential common shares outstanding during the period, which includes the additional dilution related to conversion of stock options, unvested restricted stock and unvested restricted stock units as computed under the treasury stock method. For the years ended December 31, 2015, 2014 and 2013 , the added shares from these items included in the calculation of diluted shares and EPS totaled approximately 1.4 million , 1.8 million , and 1.9 million , respectively. Potentially dilutive shares of 0.9 million , 0.6 million , and 0.5 million , respectively, have been excluded from the denominator in the computation of diluted EPS for the years ended December 31, 2015, 2014 and 2013 , respectively, because they were antidilutive. An additional 1.2 million , 0.8 million and 1.1 million performance vesting restricted stock and performance vesting restricted stock units were excluded from the computation of diluted EPS for the years ended December 31, 2015, 2014 and 2013 , respectively, because the conditions for vesting had not been met as of the balance sheet date.
Recent Accounting Pronouncements	Recent Accounting Pronouncements In May 2014, the Financial Accounting Standards Board, or FASB, issued Accounting Standards Update No. 2014-09, Revenue from Contracts with Customers: Topic 606 (ASU 2014-09), to supersede nearly all existing revenue recognition guidance under GAAP. The core principle of ASU 2014-09 is to recognize revenues when promised goods or services are transferred to customers in an amount that reflects the consideration that is expected to be received for those goods or services. ASU 2014-09 defines a five step process to achieve this core principle and, in doing so, it is possible more judgment and estimates may be required within the revenue recognition process than required under existing GAAP, including identifying performance obligations in the contract, estimating the amount of variable consideration to include in the transaction price and allocating the transaction price to each separate performance obligation. Adoption of ASU 2014-09 was initially required for fiscal and interim reporting periods beginning after December 15, 2016 using either of two methods: (i) retrospective to each prior reporting period presented with the option to elect certain practical expedients as defined within ASU 2014-09; or (ii) retrospective with the cumulative effect of initially applying ASU 2014-09 recognized at the date of initial application and providing certain additional disclosures as defined per ASU 2014-09. In August 2015, FASB issued Accounting Standards Update No. 2015-14, Revenue from Contracts with Customers - Deferral of the Effective Date: Topic 606 (ASU 2015-14) that deferred the effective date of ASU 2014-09 by one year. Application of the new revenue standard is permitted for fiscal and interim reporting periods beginning after December 15, 2016 and required for fiscal and interim reporting periods beginning after December 15, 2017. The Company is currently evaluating the potential impact of the pending adoption of ASU 2014-09 on its consolidated financial statements. In July 2015, FASB issued Accounting Standards Update No. 2015-11, Simplifying the Measurement of Inventory: Topic 330 (ASU 2015-11). Topic 330 currently requires an entity to measure inventory at the lower of cost or market. Market could be replacement cost, net realizable value, or net realizable value less an approximately normal profit margin. ASU 2015-11 requires that inventory measured using either the FIFO or average cost method be measured at the lower of cost and net realizable value. Net realizable value is the estimated selling prices in the ordinary course of business, less reasonably predictable costs of completion, disposal and transportation. Adoption of ASU 2015-11 is required for fiscal reporting periods beginning after December 15, 2016, including interim reporting periods within those fiscal years. The Company does not expect adoption of ASU 2015-11 to have a material impact on its consolidated financial statements. In November 2015, FASB issued Accounting Standards Update No. 2015-17, Balance Sheet Classification of Deferred Taxes: Topic 740 (ASU 2015-17). Current GAAP requires the deferred taxes for each jurisdiction to be presented as a net current asset or liability and net noncurrent asset or liability. This requires a jurisdiction-by-jurisdiction analysis based on the classification of the assets and liabilities to which the underlying temporary differences relate, or, in the case of loss or credit carryforwards, based on the period in which the attribute is expected to be realized. Any valuation allowance is then required to be allocated on a pro rata basis, by jurisdiction, between current and noncurrent deferred tax assets. The new guidance requires that all deferred tax assets and liabilities, along with any related valuation allowance, be classified as noncurrent on the balance sheet. As a result, each jurisdiction will now only have one net noncurrent deferred tax asset or liability. The guidance does not change the existing requirement that only permits offsetting within a jurisdiction. Adoption of ASU 2015-17 is required for fiscal reporting periods beginning after December 15, 2016, including interim reporting periods within those fiscal years, and either prospective or retrospective application is permitted. Early adoption of ASU 2015-17 is permitted. At the time of adoption, all of the Company’s deferred tax assets and liabilities, along with any related valuation allowance, will be classified as noncurrent on its Consolidated Balance Sheet. The Company does not plan to early adopt ASU 2015-17. In January 2016, FASB issued Accounting Standards Update No. 2016-01, Recognition and Measurement of Financial Assets and Financial Liabilities: Topic 825 (ASU 2016-01). The updated guidance enhances the reporting model for financial instruments, which includes amendments to address aspects of recognition, measurement, presentation and disclosure. Adoption of ASU 2016-01 is required for fiscal reporting periods beginning after December 15, 2017, including interim reporting periods within those fiscal years. The Company is currently evaluating the potential impact of the pending adoption of ASU 2016-01 on its consolidated financial statements.

Summary of Significant Accoun31

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2015
Accounting Policies [Abstract]
Schedule of Accumulated Other Comprehensive Income (Loss)	Accumulated Other Comprehensive Income Accumulated other comprehensive income, a component of Shareholders’ equity, consisted of the following at December 31 (in thousands): 2015 2014 Accumulated unrealized net gain (loss) on available-for-sale investments $ (8 ) $ 12 Accumulated currency translation adjustments 1,675 2,069 Accumulated unrealized net gain (loss) on cash flow hedges 5,975 4,422 Accumulated other comprehensive income $ 7,642 $ 6,503 The following tables show the changes in Accumulated Other Comprehensive Income by component for the years ended December 31, 2015 and 2014 (in thousands): Twelve Months Ended December 31, 2015 Unrealized Gain (Loss) on Investments Foreign Currency Translation Adjustments Unrealized Gain on Cash Flow Hedges Accumulated Other Comprehensive Income Beginning balance $ 12 $ 2,069 $ 4,422 $ 6,503 Current-period change, net of tax (20 ) (394 ) 1,553 1,139 Ending balance $ (8 ) $ 1,675 $ 5,975 $ 7,642 Income tax expense (benefit) associated with current-period change $ (13 ) $ (335 ) $ 1,005 $ 657 Twelve Months Ended December 31, 2014 Unrealized Gain on Investments Foreign Currency Translation Adjustments Unrealized Gain/(Loss) on Cash Flow Hedges Accumulated Other Comprehensive Income Beginning balance $ — $ 3,257 $ (2,404 ) $ 853 Current-period change, net of tax 12 (1,188 ) 6,826 5,650 Ending balance $ 12 $ 2,069 $ 4,422 $ 6,503 Income tax expense (benefit) associated with current-period change $ 8 $ (229 ) $ 4,593 $ 4,372

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2015
Fair Value Disclosures [Abstract]
Company's financial assets and liabilities measured at fair value and the hierarchy of the valuation inputs	The following table presents information about the Company’s financial assets and liabilities that have been measured at fair value on a recurring basis as of December 31, 2015 and 2014 , and indicates the fair value hierarchy of the valuation inputs utilized to determine such fair value (in thousands): Description Fair Value Quoted Prices in Active Markets (Level 1) Significant Other Observable Inputs (Level 2) Assets: Cash and cash equivalents and restricted cash $ 269,966 $ 269,966 $ — Available-for-sale investments (1) 14,925 14,925 — Foreign currency exchange contracts (2) 11,602 — 11,602 Assets measured at fair value at December 31, 2015 $ 296,493 $ 284,891 $ 11,602 Liabilities: Foreign currency exchange contracts (3) 3 — 3 Liabilities measured at fair value at December 31, 2015 $ 3 $ — $ 3 Description Fair Value Quoted Prices in Active Markets (Level 1) Significant Other Observable Inputs (Level 2) Assets: Cash and cash equivalents and restricted cash $ 129,507 $ 129,507 $ — Available-for-sale investments (1) 16,289 16,289 — Foreign currency exchange contracts (2) 11,079 — 11,079 Assets measured at fair value at December 31, 2014 $ 156,875 $ 145,796 $ 11,079 Liabilities: Foreign currency exchange contracts (3) 2,139 — 2,139 Liabilities measured at fair value at December 31, 2014 $ 2,139 $ — $ 2,139 _______________________________ (1) Included in “Short-term investments” on the Company’s Consolidated Balance Sheets. (2) Included in “Prepaid expenses and other current assets” and “Other non-current assets” on the Company’s Consolidated Balance Sheets. (3) Included in “Other accrued liabilities” and “Other non-current liabilities” on the Company’s Consolidated Balance Sheets.
Schedule of notional amounts of outstanding derivative positions	As of December 31, 2015 and 2014 , the Company had outstanding foreign currency exchange contracts that were designated and accounted for as cash flow hedges of anticipated future cash receipts on sales contracts payable in foreign currencies. The outstanding notional amounts were approximately (in millions): December 31, 2015 December 31, 2014 British Pounds (GBP) 39.2 77.9 Euros (EUR) 6.0 40.7 Swiss Francs (CHF) 33.0 0.9 Singapore Dollars (SGD) — 0.1 Swedish Krona (SEK) — 84.8 The Company had hedged foreign currency exposure related to these designated cash flow hedges of approximately $107.3 million and $192.5 million as of December 31, 2015 and December 31, 2014 , respectively. As of December 31, 2015 , the Company had outstanding foreign currency exchange contracts that had been dedesignated for the purposes of hedge accounting treatment. The outstanding notional amounts were approximately (in millions): December 31, 2015 December 31, 2014 British Pounds (GBP) 31.5 28.3 Euros (EUR) 3.8 — Swiss Francs (CHF) 0.3 — Japanese Yen (JPY) 274.0 —
Fair values of derivative instruments	Fair values of derivative instruments designated as cash flow hedges (in thousands): Hedge Classification Balance Sheet Location Fair Value Fair Value Foreign currency exchange contracts Prepaid expenses and other current assets $ 3,956 $ 5,360 Foreign currency exchange contracts Other non-current assets 5,183 5,717 Foreign currency exchange contracts Other accrued liabilities — (1,219 ) Foreign currency exchange contracts Other non-current liabilities (2 ) (152 ) Total fair value of derivative instruments designated as cash flow hedges $ 9,137 $ 9,706 As of December 31, 2015 and 2014 , unrecognized gains, net of tax, of $6.0 million and $4.4 million , respectively, were included in “Accumulated other comprehensive income” on the Company’s Consolidated Balance Sheets. Fair values of derivative instruments not designated as cash flow hedges (in thousands): Hedge Classification Balance Sheet Location Fair Value Fair Value Foreign currency exchange contracts Prepaid expenses and other current assets $ 1,807 $ 2 Foreign currency exchange contracts Other non-current assets 656 — Foreign currency exchange contracts Other accrued liabilities (1 ) (235 ) Foreign currency exchange contracts Other non-current liabilities — (533 ) Total fair value of derivative instruments not designated as cash flow hedges $ 2,462 $ (766 )

Accumulated Other Comprehensi33

Accumulated Other Comprehensive Income (Tables)	12 Months Ended
	Dec. 31, 2015
Other Comprehensive Income (Loss), Net of Tax [Abstract]
Reclassification from Accumulated Other Comprehensive Income	The following table shows the impact on product revenue of reclassification adjustments from accumulated other comprehensive income resulting from hedged foreign currency transactions recorded by the Company for the years ended December 31, 2015 , 2014 and 2013 (in thousands). The gross reclassification adjustments increased product revenue for the years ended December 31, 2015 and 2014 and decreased product revenue for the year ended December 31, 2013. Year Ended 2015 2014 2013 Gross of Tax Reclassifications $ 6,163 $ 2,748 $ (1,604 ) Net of Tax Reclassifications $ 3,698 $ 1,649 $ (962 )
Schedule of Accumulated Other Comprehensive Income (Loss)	Accumulated Other Comprehensive Income Accumulated other comprehensive income, a component of Shareholders’ equity, consisted of the following at December 31 (in thousands): 2015 2014 Accumulated unrealized net gain (loss) on available-for-sale investments $ (8 ) $ 12 Accumulated currency translation adjustments 1,675 2,069 Accumulated unrealized net gain (loss) on cash flow hedges 5,975 4,422 Accumulated other comprehensive income $ 7,642 $ 6,503 The following tables show the changes in Accumulated Other Comprehensive Income by component for the years ended December 31, 2015 and 2014 (in thousands): Twelve Months Ended December 31, 2015 Unrealized Gain (Loss) on Investments Foreign Currency Translation Adjustments Unrealized Gain on Cash Flow Hedges Accumulated Other Comprehensive Income Beginning balance $ 12 $ 2,069 $ 4,422 $ 6,503 Current-period change, net of tax (20 ) (394 ) 1,553 1,139 Ending balance $ (8 ) $ 1,675 $ 5,975 $ 7,642 Income tax expense (benefit) associated with current-period change $ (13 ) $ (335 ) $ 1,005 $ 657 Twelve Months Ended December 31, 2014 Unrealized Gain on Investments Foreign Currency Translation Adjustments Unrealized Gain/(Loss) on Cash Flow Hedges Accumulated Other Comprehensive Income Beginning balance $ — $ 3,257 $ (2,404 ) $ 853 Current-period change, net of tax 12 (1,188 ) 6,826 5,650 Ending balance $ 12 $ 2,069 $ 4,422 $ 6,503 Income tax expense (benefit) associated with current-period change $ 8 $ (229 ) $ 4,593 $ 4,372

Investments (Tables)

Investments (Tables)	12 Months Ended
	Dec. 31, 2015
Investments, Debt and Equity Securities [Abstract]
Investments	The carrying amount of the Company’s investments in available-for-sale securities as of December 31, 2015 and December 31, 2014 are shown in the table below (in thousands): December 31, 2015 December 31, 2014 Short-term available-for-sale securities cost $ 14,939 $ 16,269 Short-term available-for-sale securities unrealized gain (loss) (14 ) 20 Short-term available-for-sale securities fair value $ 14,925 $ 16,289

Accounts and Other Receivable35

Accounts and Other Receivables, Net (Tables)	12 Months Ended
	Dec. 31, 2015
Receivables [Abstract]
Accounts and Other Receivables, Net	A summary of net accounts and other receivables follows (in thousands): December 31, 2015 2014 Trade accounts receivable $ 83,750 $ 126,874 Unbilled receivables 7,685 20,788 Advance billings 11,637 4,960 Short-term investment in sales-type lease 10,004 10,187 Other receivables 11,662 2,401 124,738 165,210 Allowance for doubtful accounts (19 ) (97 ) Accounts and other receivables, net $ 124,719 $ 165,113

Sales-Type Lease (Tables)

Sales-Type Lease (Tables)	12 Months Ended
	Dec. 31, 2015
Leases [Abstract]
Components of the Net Investment in the Sales-type Lease	The following table shows the components of the net investment in the sales-type lease as of December 31, 2015 and 2014 (in thousands): December 31 2015 2014 Total minimum lease payments to be received $ 36,863 $ 53,134 Less: executory costs (7,434 ) (10,717 ) Net minimum lease payments receivable 29,429 42,417 Estimated residual value of leased property (unguaranteed) — 1,253 Less: unearned income (1,108 ) (2,394 ) Net investment in sales-type lease 28,321 41,276 Less: long-term investment in sales-type lease (18,317 ) (31,089 ) Investment in sales-type lease included in accounts and other receivables $ 10,004 $ 10,187
Minimum Lease Payments to be Received for Each of the Next Three Fiscal Years	As of December 31, 2015 , minimum lease payments for each of the succeeding three fiscal years were as follows (in thousands): 2016 $ 13,405 2017 13,405 2018 10,053 Total minimum lease payments to be received $ 36,863

Inventory (Tables)

Inventory (Tables)	12 Months Ended
	Dec. 31, 2015
Inventory Disclosure [Abstract]
Inventory	A summary of inventory follows (in thousands): December 31 2015 2014 Components and subassemblies $ 20,806 $ 60,851 Work in process 43,071 46,954 Finished goods 49,778 35,827 $ 113,655 $ 143,632

Property and Equipment, Net (Ta

Property and Equipment, Net (Tables)	12 Months Ended
	Dec. 31, 2015
Property, Plant and Equipment [Abstract]
Property and Equipment, Net	A summary of property and equipment follows (in thousands): December 31, 2015 2014 Land $ 275 $ 275 Buildings 20,612 20,409 Furniture and equipment 14,190 13,198 Computer equipment 65,957 59,785 Leasehold improvements 1,098 446 102,132 94,113 Accumulated depreciation and amortization (71,053 ) (59,320 ) Property and equipment, net $ 31,079 $ 34,793

Service Spares, Net (Tables)

Service Spares, Net (Tables)	12 Months Ended
	Dec. 31, 2015
Inventory Disclosure [Abstract]
Service Spares, Net	A summary of service spares follows (in thousands): December 31, 2015 2014 Service spares $ 15,082 $ 13,114 Accumulated depreciation (11,992 ) (11,246 ) Service spares, net $ 3,090 $ 1,868

Deferred Revenue (Tables)

Deferred Revenue (Tables)	12 Months Ended
	Dec. 31, 2015
Deferred Revenue Disclosure [Abstract]
Deferred revenue	A summary of deferred revenue follows (in thousands): December 31 2015 2014 Deferred product revenue $ 22,215 $ 21,152 Deferred service revenue 97,822 92,346 Total deferred revenue 120,037 113,498 Less long-term deferred revenue (33,306 ) (47,588 ) Deferred revenue in current liabilities $ 86,731 $ 65,910

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2015
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Minimum contractual commitments as of December 31, 2015 , were as follows (in thousands): Operating Leases Development Agreements 2016 $ 5,484 $ 15,567 2017 5,149 233 2018 4,939 150 2019 4,668 25 2020 3,391 — Thereafter 12,519 — Minimum contractual commitments $ 36,150 $ 15,975

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Income (loss) before income taxes	Income before income taxes consisted of the following (in thousands): Year Ended December 31, 2015 2014 2013 United States $ 38,362 $ 5,710 $ 17,467 International 4,415 3,987 3,562 Total $ 42,777 $ 9,697 $ 21,029
Tax provision (benefit) for income taxes related to operations	The tax provision (benefit) for income taxes related to operations consisted of the following (in thousands): Year Ended December 31, 2015 2014 2013 Current provision: Federal $ 725 $ 230 $ 484 State 1,389 (392 ) 696 Foreign 1,023 740 801 Total current provision 3,137 578 1,981 Deferred provision (benefit): Federal 12,198 (53,242 ) (13,160 ) State (52 ) (885 ) (327 ) Foreign (43 ) 923 312 Total deferred provision (benefit) 12,103 (53,204 ) (13,175 ) Total provision (benefit) for income taxes $ 15,240 $ (52,626 ) $ (11,194 )
Tax provision (benefit) differs from the amount computed by applying the federal statutory income tax rate	The tax provision (benefit) differs from the amount computed by applying the federal statutory income tax rate as follows (in thousands): Year Ended December 31, 2015 2014 2013 Income tax provision at statutory rate $ 14,972 $ 3,394 $ 7,360 State taxes, net of federal benefit 897 (217 ) 369 Foreign income taxes (12 ) 284 (749 ) Share-based compensation adjustment — — (8,419 ) Deemed dividends for U.S. income tax purposes 407 492 477 Nondeductible expenses 283 337 208 Disallowed compensation 455 (116 ) 19 Research and development tax credit (1,733 ) (1,140 ) (5,736 ) Effect of change in valuation allowance on deferred tax assets (29 ) (55,660 ) (4,723 ) Effective income tax provision (benefit) $ 15,240 $ (52,626 ) $ (11,194 )
Significant components of the Company's deferred income tax assets and liabilities	Significant components of the Company’s deferred income tax assets and liabilities follow (in thousands): December 31, 2015 2014 Current: Deferred Income Tax Assets Inventory $ 3,930 $ 5,840 Accrued compensation 1,213 681 Deferred revenue 18,372 18,186 Net operating loss carryforwards 2,636 12,981 Research and experimentation credit carryforwards 16,264 — Other 4,303 1,261 Gross current deferred tax assets 46,718 38,949 Valuation allowance (2,995 ) (2,039 ) Current deferred tax assets 43,723 36,910 Deferred Income Tax Liabilities Other (5,095 ) (837 ) Current deferred tax liabilities (5,095 ) (837 ) Net current deferred tax assets $ 38,628 $ 36,073 Long-Term: Deferred Income Tax Assets Property and equipment $ 7,510 $ 11,555 Research and experimentation credit carryforwards 9,528 24,596 Net operating loss carryforwards 14,523 21,511 Goodwill 125 203 Share-based compensation 5,976 5,000 Other 4,084 4,967 Gross long-term deferred tax assets 41,746 67,832 Valuation allowance (6,492 ) (8,099 ) Long-term deferred tax assets 35,254 59,733 Deferred Income Tax Liabilities Investment in sales-type lease, net (7,611 ) (14,321 ) Intangible assets (512 ) (1,215 ) Other (1,277 ) (2,783 ) Long-term deferred tax liabilities (9,400 ) (18,319 ) Net long-term deferred tax asset $ 25,854 $ 41,414
Unrecognized tax benefits for uncertain tax positions	The following table summarizes changes in the amount of the Company’s unrecognized tax benefits for uncertain tax positions for the three years ended December 31, 2015, 2014 and 2013 (in thousands): Balance at December 31, 2012 $ 470 Decrease related to prior year income tax positions (268 ) Balance at December 31, 2013 $ 202 Increase related to prior year income tax positions 5,059 Increase related to current year income tax positions 369 Balance at December 31, 2014 $ 5,630 Increase related to prior year income tax positions 151 Increase related to current year income tax positions 433 Balance at December 31, 2015 $ 6,214

Shareholders' Equity (Tables)

Shareholders' Equity (Tables)	12 Months Ended
	Dec. 31, 2015
Share-based Compensation [Abstract]
Key weighted average assumptions used in determining fair value	The following key weighted average assumptions were employed in the calculation for the years ended December 31: 2015 2014 2013 Risk-free interest rate 1.31 % 1.22 % 0.98 % Expected dividend yield — % — % — % Volatility 50.55 % 52.43 % 50.45 % Expected life (in years) 4.0 4.0 4.0 Weighted average Black-Scholes value of options granted $ 11.23 $ 11.16 $ 8.22
Stock option activity	A summary of the Company’s stock option activity and related information follows: Options Weighted Average Exercise Price Weighted Average Remaining Contractual Term (Years) Outstanding at January 1, 2013 2,293,505 $ 7.31 Granted 346,360 20.65 Exercised (495,221 ) 6.38 Canceled and forfeited (66,575 ) 21.97 Outstanding at December 31, 2013 2,078,069 9.29 Granted 323,900 26.92 Exercised (411,352 ) 7.50 Canceled and forfeited (59,627 ) 18.45 Outstanding at December 31, 2014 1,930,990 12.34 Granted 307,450 27.86 Exercised (229,118 ) 9.99 Canceled and forfeited (60,847 ) 20.00 Outstanding at December 31, 2015 1,948,475 14.83 6.3 Exercisable at December 31, 2015 1,357,512 10.40 5.3 Available for grant at December 31, 2015 1,791,731
Outstanding and exercisable options by price range	Outstanding and exercisable options by price range as of December 31, 2015 , were as follows: Outstanding Options Exercisable Options Range of Exercise Prices per Share Number Outstanding Weighted Average Remaining Life (Years) Weighted Average Exercise Price Number Exercisable Weighted Average Exercise Price $ 0.00 - $ 10.00 879,263 4.2 $ 5.67 879,179 $ 5.67 $ 10.01 - $ 20.00 412,016 6.9 $ 15.21 293,735 $ 14.51 $ 20.01 - $ 27.00 367,794 8.5 $ 25.44 115,590 $ 24.87 $ 27.01 - $ 34.52 289,402 9.0 $ 28.60 69,008 $ 28.96 $ 0.00 - $ 34.52 1,948,475 6.3 $ 14.83 1,357,512 $ 10.40
Restricted stock activity	Restricted Stock: During 2015 , 2014 and 2013 , the Company issued an aggregate of 45,175 , 463,734 , and 755,979 shares of restricted stock, respectively, to certain directors, executives and other employees. The grant date fair value of these grants was approximately $1.4 million , $13.3 million , and $15.8 million for 2015 , 2014 and 2013 , respectively. Share-based compensation expense is recorded over the vesting period, which is generally one year for non-employee directors and four years for officers and employees of the Company. A summary of the Company’s unvested restricted stock grants and changes during the years ended December 31 is as follows: Service Vesting Restricted Shares Performance Vesting Restricted Shares Total Restricted Shares Shares Weighted Average Grant Date Fair Value Shares Weighted Shares Weighted Average Grant Date Fair Value Outstanding at January 1, 2013 1,465,738 $ 7.44 737,000 $ 12.90 2,202,738 $ 9.27 Granted 326,979 20.83 429,000 21.00 755,979 20.93 Forfeited (3,437 ) 5.92 (72,000 ) 14.88 (75,437 ) 14.48 Vested (661,580 ) 6.22 — — (661,580 ) 6.22 Outstanding at December 31, 2013 1,127,700 12.05 1,094,000 15.94 2,221,700 13.97 Granted 463,734 28.74 — — 463,734 28.74 Forfeited (134,653 ) 15.39 (277,000 ) 17.49 (411,653 ) 16.80 Vested (423,179 ) 11.14 — — (423,179 ) 11.14 Outstanding at December 31, 2014 1,033,602 19.48 817,000 15.41 1,850,602 17.68 Granted 45,175 30.44 — — 45,175 30.44 Forfeited (48,998 ) 24.00 (219,000 ) 15.60 (267,998 ) 17.14 Vested (513,336 ) 15.34 (12,500 ) 28.20 (525,836 ) 15.64 Outstanding at December 31, 2015 516,443 24.12 585,500 15.07 1,101,943 19.31 The estimated forfeiture rate applied to the Company’s service vesting restricted stock grants during the years ended December 31, 2015 and 2014 were 8.0% and 6.3% , respectively. The aggregate fair value of restricted shares vested during 2015 , 2014 and 2013 was $14.2 million , $11.9 million , and $14.0 million , respectively. The performance vesting restricted shares that remain outstanding are subject to performance measures that are currently not considered "probable" of attainment and as such, no compensation cost has been recorded for these grants. The performance vesting restricted shares are eligible to vest between 2016 and 2017 . Restricted Stock Units: During 2015 , the Company issued an aggregate of 984,850 restricted stock and performance restricted stock units with a grant date fair value of approximately $29.5 million . There were no restricted stock units issued or outstanding as of December 31, 2014 and 2013 . Restricted stock units have similar vesting characteristics as restricted stock but are not outstanding shares and do not have any voting or dividend rights. The Company records share-based compensation expense over the vesting period. At the time of vesting, a share of common stock representing each restricted stock unit vested will be issued by the Company. A summary of the Company’s unvested restricted stock unit grants and changes during the year ended December 31, 2015 is as follows: Service Vesting Restricted Stock Units Performance Vesting Restricted Stock Units Total Restricted Stock Units Units Weighted Units Weighted Units Weighted Average Grant Date Fair Value Outstanding at December 31, 2014 — $ — — $ — — $ — Granted 285,550 $ 29.78 699,300 $ 30.04 984,850 $ 29.97 Forfeited (12,500 ) $ 30.48 (66,600 ) $ 30.04 (79,100 ) $ 30.11 Vested — $ — — $ — — $ — Outstanding at December 31, 2015 273,050 $ 29.75 632,700 $ 30.04 905,750 $ 29.95 The estimated forfeiture rate applied to the Company’s service vesting restricted stock unit grants during the year ended December 31, 2015 was 8.0% . The performance vesting restricted stock units are subject to performance measures that are currently not considered "probable" of attainment and as such, no compensation cost has been recorded for these units. The performance vesting restricted stock units are eligible to vest between 2017 and 2020 .
Gross share-based compensation cost recorded in the condensed consolidated statements of operations	The following table sets forth the gross share-based compensation cost resulting from stock options, unvested restricted stock and unvested restricted stock units that were recorded in the Company’s Consolidated Statements of Operations for the years ended December 31 (in thousands): 2015 2014 2013 Cost of product revenue $ 254 $ 229 $ 135 Cost of service revenue 276 255 229 Research and development 3,770 2,721 1,480 Sales and marketing 3,047 3,152 2,230 General and administrative 4,006 4,007 3,165 Total share-based compensation expense $ 11,353 $ 10,364 $ 7,239

Segment Information (Tables)

Segment Information (Tables)	12 Months Ended
	Dec. 31, 2015
Segment Reporting [Abstract]
Information on operating segments	The following table presents revenues and gross margin for the Company’s operating segments for the years ended December 31 (in thousands): 2015 2014 2013 Revenue: Supercomputing $ 581,733 $ 459,729 $ 434,133 Storage and Data Management 112,862 84,412 76,955 Maintenance and Support 97,091 86,573 77,817 Engineering Services and Other 30,094 17,465 14,661 Elimination of inter-segment revenue (97,091 ) (86,573 ) (77,817 ) Total revenue $ 724,689 $ 561,606 $ 525,749 Gross Profit: Supercomputing $ 177,048 $ 146,565 $ 143,440 Storage and Data Management 37,181 31,572 31,403 Maintenance and Support 41,487 38,819 38,476 Engineering Services and Other 11,454 6,277 9,483 Elimination of inter-segment gross profit (41,487 ) (38,819 ) (38,476 ) Total gross profit $ 225,683 $ 184,414 $ 184,326
Revenue by geographic location	The following data represents the Company’s revenue and long-lived assets for the United States and all other countries (in thousands): United States All Other Countries Total For the year ended December 31, 2015: Product revenue $ 373,494 $ 227,800 $ 601,294 Service revenue $ 88,956 $ 34,439 $ 123,395 Long-lived assets $ 55,227 $ 23,731 $ 78,958 For the year ended December 31, 2014: Product revenue $ 253,930 $ 206,818 $ 460,748 Service revenue $ 72,434 $ 28,424 $ 100,858 Long-lived assets $ 58,868 $ 36,792 $ 95,660 For the year ended December 31, 2013: Product revenue $ 297,583 $ 138,747 $ 436,330 Service revenue $ 62,072 $ 27,347 $ 89,419 Long-lived assets $ 58,910 $ 6,146 $ 65,056

Research and Development (Table

Research and Development (Tables)	12 Months Ended
	Dec. 31, 2015
Research and Development [Abstract]
Company's Net Research and Development Cost	The detail for the Company’s net research and development costs for the years ended December 31 follows (in thousands): 2015 2014 2013 Gross research and development expenses $ 126,060 $ 104,797 $ 92,469 Less: Amounts included in cost of revenue (16,515 ) (7,713 ) (3,741 ) Less: Reimbursed research and development (excludes amounts in revenue) (12,982 ) (3,036 ) (1,000 ) Net research and development expenses $ 96,563 $ 94,048 $ 87,728

Interest Income (Expense) (Tabl

Interest Income (Expense) (Tables)	12 Months Ended
	Dec. 31, 2015
Other Income and Expenses [Abstract]
The detail of interest income (expense) for the years ended	The detail of interest income (expense) for the years ended December 31 follows (in thousands): 2015 2014 2013 Interest income $ 1,465 $ 643 $ 894 Interest expense (57 ) (137 ) (137 ) Net interest income $ 1,408 $ 506 $ 757

Quarterly Data (Unaudited) (Tab

Quarterly Data (Unaudited) (Tables)	12 Months Ended
	Dec. 31, 2015
Quarterly Financial Information Disclosure [Abstract]
Schedule of Quarterly Financial Information	The following table presents unaudited quarterly financial information for the two years ended December 31, 2015 . In the opinion of management, this information contains all adjustments, consisting only of normal recurring adjustments, necessary for a fair presentation thereof. The operating results are not necessarily indicative of results for any future periods. Quarter-to-quarter comparisons should not be relied upon as indicators of future performance. The Company’s business is driven by a few significant contracts and, as a result, the Company’s operating results are subject to very large quarterly fluctuations. The Company’s earnings per share for the full year may not equal the sum of the four quarterly earnings per share amounts because of common share activity during the year. (In thousands, except per share data) 2015 2014 For the Quarter Ended 3/31 6/30 9/30 12/31 3/31 6/30 9/30 12/31 Revenue $ 79,644 $ 186,161 $ 191,413 $ 267,471 $ 55,110 $ 85,147 $ 159,406 $ 261,943 Cost of revenue 55,608 136,576 125,531 181,291 37,173 56,143 110,876 173,000 Gross profit 24,036 49,585 65,882 86,180 17,937 29,004 48,530 88,943 Research and development, net 22,187 20,106 24,989 29,281 22,621 24,189 22,503 24,735 Sales and marketing 12,552 13,412 16,132 18,054 11,776 13,259 14,808 17,942 General and administrative 6,140 6,435 6,729 8,662 5,413 5,316 5,813 6,839 Net income (loss) (1) (9,394 ) 5,781 10,855 20,295 (12,938 ) (6,748 ) 7,371 74,638 Net income (loss) per common share, basic $ (0.24 ) $ 0.15 $ 0.28 $ 0.51 $ (0.34 ) $ (0.18 ) $ 0.19 $ 1.92 Net income (loss) per common share, diluted $ (0.24 ) $ 0.14 $ 0.27 $ 0.50 $ (0.34 ) $ (0.18 ) $ 0.18 $ 1.84 (1) The fourth quarter of 2014 includes the impact of the reduction of substantially all of the valuation allowance held against the Company’s U.S. deferred tax assets.

Summary of Significant Accoun48

Summary of Significant Accounting Policies Cash, Cash Equivalents and Restricted Cash (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Restricted Cash and Cash Equivalents Items [Line Items]
Short-term restricted cash	$ 1,651	$ 16,874
Long-term restricted cash	$ 1,655	$ 0
Long-term investments, expected term	1 year
Minimum
Restricted Cash and Cash Equivalents Items [Line Items]
Short term investments, expected term	3 months
Maximum
Restricted Cash and Cash Equivalents Items [Line Items]
Short term investments, expected term	1 year

Summary of Significant Accoun49

Summary of Significant Accounting Policies Property and Equipment and Intangible Assets (Details)	12 Months Ended
	Dec. 31, 2015
Minimum
Property, Plant and Equpment and Intangible Assets [Line Items]
Intangible assets, useful lives (years)	2 years
Maximum
Property, Plant and Equpment and Intangible Assets [Line Items]
Intangible assets, useful lives (years)	10 years
Furniture and Fixtures | Minimum
Property, Plant and Equpment and Intangible Assets [Line Items]
Property and equipment, useful lives (years)	18 months
Furniture and Fixtures | Maximum
Property, Plant and Equpment and Intangible Assets [Line Items]
Property and equipment, useful lives (years)	7 years
Computer equipment
Property, Plant and Equpment and Intangible Assets [Line Items]
Property and equipment, useful lives (years)	3 years
Building and Building Improvements | Minimum
Property, Plant and Equpment and Intangible Assets [Line Items]
Property and equipment, useful lives (years)	8 years
Building and Building Improvements | Maximum
Property, Plant and Equpment and Intangible Assets [Line Items]
Property and equipment, useful lives (years)	25 years

Summary of Significant Accoun50

Summary of Significant Accounting Policies Service Spares (Details)	12 Months Ended
	Dec. 31, 2015
Accounting Policies [Abstract]
Service spares, useful life	4 years

Summary of Significant Accoun51

Summary of Significant Accounting Policies Revenue Recognition (Details)	12 Months Ended
	Dec. 31, 2015
Accounting Policies [Abstract]
Product Delivery Period	5 years
Maintenance Services Period	1 year

Summary of Significant Accoun52

Summary of Significant Accounting Policies Sales-type leases (Details)	12 Months Ended
	Dec. 31, 2015
Minimum
Capital Leased Assets [Line Items]
Economic life of product	3 years
Maximum
Capital Leased Assets [Line Items]
Economic life of product	4 years

Summary of Significant Accoun53

Summary of Significant Accounting Policies Foreign Currency Translation and Transaction (Details) - Other (Income) Expense, Net - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Foreign Currency Translations and Transactions [Line Items]
Net transaction gains	$ (1.6)	$ (2.1)
Net transaction losses			$ 1.3

Summary of Significant Accoun54

Summary of Significant Accounting Policies Income Taxes (Details) $ in Millions	Dec. 31, 2015USD ($)
Accounting Policies [Abstract]
Net deferred tax assets	$ 74
Valuation allowance amount	(9.5)
Net deferred tax assets of valuation allowance	$ 64.5

Summary of Significant Accoun55

Summary of Significant Accounting Policies Advertising Costs (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Accounting Policies [Abstract]
Advertising expenses	$ 2.3	$ 2.9	$ 2.2

Summary of Significant Accoun56

Summary of Significant Accounting Policies EPS (Details) - shares shares in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares added from these items included in the calculation of diluted shares and EPS	1.4	1.8	1.9
Time-vesting Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Potentially dilutive shares excluded from the denominator in the computation of diluted EPS	0.9	0.6	0.5
Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Potentially dilutive shares excluded from the denominator in the computation of diluted EPS	1.2	0.8	1.1

Summary of Significant Accoun57

Summary of Significant Accounting Policies Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax	$ 7,642	$ 6,503	$ 853
Accumulated unrealized net loss on available-for-sale investments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax	(8)	12	0
Accumulated currency translation adjustments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax	1,675	2,069	3,257
Accumulated other comprehensive income
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax	$ 5,975	$ 4,422	$ (2,404)

Fair Value Measurements Fair Va

Fair Value Measurements Fair Value (Details) - USD ($) $ in Thousands		Dec. 31, 2015	Dec. 31, 2014
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and Cash Equivalents, Fair Value Disclosure		$ 269,966	$ 129,507
Available-for-sale Securities	[1]	14,925	16,289
Foreign Currency Contract, Asset, Fair Value Disclosure	[2]	11,602	11,079
Assets, Fair Value Disclosure		296,493	156,875
Foreign Currency Contracts, Liability, Fair Value Disclosure	[3]	3	2,139
Financial and Nonfinancial Liabilities, Fair Value Disclosure		3	2,139
Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and Cash Equivalents, Fair Value Disclosure		269,966	129,507
Available-for-sale Securities	[1]	14,925	16,289
Foreign Currency Contract, Asset, Fair Value Disclosure	[2]	0	0
Assets, Fair Value Disclosure		284,891	145,796
Foreign Currency Contracts, Liability, Fair Value Disclosure	[3]	0	0
Financial and Nonfinancial Liabilities, Fair Value Disclosure		0	0
Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and Cash Equivalents, Fair Value Disclosure		0	0
Available-for-sale Securities	[1]	0	0
Foreign Currency Contract, Asset, Fair Value Disclosure	[2]	11,602	11,079
Assets, Fair Value Disclosure		11,602	11,079
Foreign Currency Contracts, Liability, Fair Value Disclosure	[3]	3	2,139
Financial and Nonfinancial Liabilities, Fair Value Disclosure		$ 3	$ 2,139
[1]	Included in “Short-term investments” on the Company’s Consolidated Balance Sheets.
[2]	Included in “Prepaid expenses and other current assets” and “Other non-current assets” on the Company’s Consolidated Balance Sheets.
[3]	Included in “Other accrued liabilities” and “Other non-current liabilities” on the Company’s Consolidated Balance Sheets.

Fair Value Measurements Derivat

Fair Value Measurements Derivatives (Details) $ in Thousands, € in Millions, ¥ in Millions, £ in Millions, SGD in Millions, SFr in Millions, SEK in Millions

12 Months Ended

Dec. 31, 2015USD ($)

Dec. 31, 2014USD ($)

Dec. 31, 2015EUR (€)

Dec. 31, 2015USD ($)

Dec. 31, 2015SEK

Dec. 31, 2015SGD

Dec. 31, 2015CHF (SFr)

Dec. 31, 2015JPY (¥)

Dec. 31, 2015GBP (£)

Dec. 31, 2014EUR (€)

Dec. 31, 2014USD ($)

Dec. 31, 2014SEK

Dec. 31, 2014SGD

Dec. 31, 2014CHF (SFr)

Dec. 31, 2014JPY (¥)

Dec. 31, 2014GBP (£)

Dec. 31, 2013USD ($)

Derivative [Line Items]

Hedged Foreign Currency Exposure

$ 107,300

$ 192,500

Foreign Currency Exposure on Dedesignated Foreign Currency Contracts

55,600

43,400

Foreign Currency Contract, Asset, Fair Value Disclosure

[1]

11,602

11,079

Foreign Currency Contracts, Liability, Fair Value Disclosure

[2]

(3)

(2,139)

Accumulated Other Comprehensive Income (Loss), Net of Tax

7,642

6,503

$ 853

Foreign Exchange Contract [Member]

Derivative [Line Items]

Derivative, Gain (Loss) on Derivative, Net

$ 11,600

$ 8,900

Accumulated Other Comprehensive Income (Loss), Net of Tax

6,000

4,400

Not Designated as Hedging Instrument [Member]

Derivative [Line Items]

Derivative, Notional Amount

€ 3.8

SFr 0.3

¥ 274

£ 31.5

€ 0

SFr 0

¥ 0

£ 28.3

Foreign Currency Derivative Instruments Not Designated as Hedging Instruments at Fair Value, Net

(2,462)

766

Designated as Hedging Instrument [Member]

Derivative [Line Items]

Derivative, Notional Amount

€ 6

SEK 0

SGD 0

SFr 33

£ 39.2

€ 40.7

SEK 84.8

SGD 0.1

SFr 0.9

£ 77.9

Foreign Currency Cash Flow Hedge Derivative at Fair Value, Net

(9,137)

(9,706)

Prepaid Expenses and Other Current Assets [Member] | Not Designated as Hedging Instrument [Member]

Derivative [Line Items]

Foreign Currency Contract, Asset, Fair Value Disclosure

1,807

2

Prepaid Expenses and Other Current Assets [Member] | Designated as Hedging Instrument [Member]

Derivative [Line Items]

Foreign Currency Contract, Asset, Fair Value Disclosure

3,956

5,360

Other Noncurrent Assets [Member] | Not Designated as Hedging Instrument [Member]

Derivative [Line Items]

Foreign Currency Contract, Asset, Fair Value Disclosure

656

0

Other Noncurrent Assets [Member] | Designated as Hedging Instrument [Member]

Derivative [Line Items]

Foreign Currency Contract, Asset, Fair Value Disclosure

5,183

5,717

Other Current Liabilities [Member] | Not Designated as Hedging Instrument [Member]

Derivative [Line Items]

Foreign Currency Contracts, Liability, Fair Value Disclosure

(1)

(235)

Other Current Liabilities [Member] | Designated as Hedging Instrument [Member]

Derivative [Line Items]

Foreign Currency Contracts, Liability, Fair Value Disclosure

0

(1,219)

Other Noncurrent Liabilities [Member] | Not Designated as Hedging Instrument [Member]

Derivative [Line Items]

Foreign Currency Contracts, Liability, Fair Value Disclosure

0

(533)

Other Noncurrent Liabilities [Member] | Designated as Hedging Instrument [Member]

Derivative [Line Items]

Foreign Currency Contracts, Liability, Fair Value Disclosure

$ (2)

$ (152)

[1]

Included in “Prepaid expenses and other current assets” and “Other non-current assets” on the Company’s Consolidated Balance Sheets.

[2]

Included in “Other accrued liabilities” and “Other non-current liabilities” on the Company’s Consolidated Balance Sheets.

Accumulated Other Comprehensi60

Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, before Tax	$ 6,163	$ 2,748	$ (1,604)
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Net of Tax	3,698	1,649	(962)
Accumulated Other Comprehensive Income (Loss), Net of Tax	7,642	6,503	853
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax	(394)	(1,188)	(1,044)
Other Comprehensive Income (Loss), Net of Tax	1,139	5,650	(4,328)
Other Comprehensive Income (Loss), Tax	657	4,372
Accumulated Net Unrealized Investment Gain (Loss) [Member]
Accumulated Other Comprehensive Income (Loss), Net of Tax	(8)	12	0
Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, Net of Tax	(20)	12
Other Comprehensive Income (Loss), Tax	(13)	8
Accumulated Translation Adjustment [Member]
Accumulated Other Comprehensive Income (Loss), Net of Tax	1,675	2,069	3,257
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax	(394)	(1,188)
Other Comprehensive Income (Loss), Tax	(335)	(229)
Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member]
Accumulated Other Comprehensive Income (Loss), Net of Tax	5,975	4,422	$ (2,404)
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax	1,553	6,826
Other Comprehensive Income (Loss), Tax	$ 1,005	$ 4,593

Investments (Details)

Investments (Details) - USD ($) $ in Thousands		Dec. 31, 2015	Dec. 31, 2014
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities	[1]	$ 14,925	$ 16,289
Short-term Investments [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost Basis		14,939	16,269
Available-for-sale Securities, Accumulated Gross Unrealized Gain (Loss), before Tax		$ (14)	$ 20
[1]	Included in “Short-term investments” on the Company’s Consolidated Balance Sheets.

Accounts and Other Receivable62

Accounts and Other Receivables, Net (Details) $ in Thousands	Dec. 31, 2015USD ($)Customers	Dec. 31, 2014USD ($)Customers
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts Receivable, Gross, Current	$ 124,738	$ 165,210
Allowance for Doubtful Accounts Receivable, Current	(19)	(97)
Accounts Receivable, Net, Current	124,719	165,113
Trade Accounts Receivable [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts Receivable, Gross, Current	83,750	126,874
Unbilled Receivables [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts Receivable, Gross, Current	7,685	20,788
Advance Billings [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts Receivable, Gross, Current	11,637	4,960
Financing Receivable [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts Receivable, Gross, Current	10,004	10,187
Other Receivables [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts Receivable, Gross, Current	11,662	2,401
US Government Agencies and Customers [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts Receivable, Gross, Current	$ 44,200	$ 87,000
Non US Government Customers [Member] | Accounts Receivable [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Concentration Risk, Number of Customers | Customers	1	0
Concentration Risk, Percent	18.00%	10.00%
Unbilled Revenues [Member] | US Government Agencies and Customers [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts Receivable, Gross, Current	$ 2,200	$ 2,100

Sales-Type Lease (Details)

Sales-Type Lease (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Leases [Abstract]
Capital Leases, Net Investment in Sales Type Leases, Minimum Payments to be Received	$ 36,863	$ 53,134
Capital Leases, Net Investment in Sales Type Leases, Executory Costs	(7,434)	(10,717)
Capital Leases, Net Investment in Sales Type Leases, Minimum Payments to be Received, Less Executory Costs	29,429	42,417
Capital Leases, Net Investment in Sales Type Leases, Unguaranteed Residual Values of Leased Property	0	1,253
Capital Leases, Net Investment in Sales Type Leases, Deferred Income	(1,108)	(2,394)
Capital Leases, Net Investment in Sales Type Leases	28,321	41,276
Capital Leases, Lessor Balance Sheet, Net Investment in Direct Financing and Sales Type Leases, Noncurrent	(18,317)	(31,089)
Capital Leases, Lessor Balance Sheet, Net Investment in Sales Type Leases, Current	10,004	$ 10,187
Capital Leases, Future Minimum Payments Receivable, Next Twelve Months	13,405
Capital Leases, Future Minimum Payments, Receivable in Two Years	13,405
Capital Leases, Future Minimum Payments, Receivable in Three Years	10,053
Capital Leases, Future Minimum Payments Receivable	$ 36,863

Inventory (Details)

Inventory (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2015USD ($)Customers	Dec. 31, 2014USD ($)Customers	Dec. 31, 2013USD ($)
Inventory [Line Items]
Inventory, Raw Materials and Supplies, Net of Reserves	$ 20,806	$ 60,851
Inventory, Work in Process, Net of Reserves	43,071	46,954
Inventory, Finished Goods, Net of Reserves	49,778	35,827
Inventory, Net	113,655	143,632
Other Inventory, in Transit, Gross	49,500	35,300
Inventory Write-down	$ 500	$ 2,300	$ 900
Finished Goods Inventory [Member]
Inventory [Line Items]
Number of Customers Accounted for Finished Goods Inventory | Customers	3	2
Finished Goods Owned by Majority Customer Value	$ 41,700	$ 31,200

Property and Equipment, Net (De

Property and Equipment, Net (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	$ 102,132	$ 94,113
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment	(71,053)	(59,320)
Property, Plant and Equipment, Net	31,079	34,793
Depreciation	13,300	12,800	$ 10,900
Land [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	275	275
Building [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	20,612	20,409
Furniture and Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	14,190	13,198
Computer Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	65,957	59,785
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	$ 1,098	$ 446

Service Spares, Net (Details)

Service Spares, Net (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Inventory Disclosure [Abstract]
Other Depreciation and Amortization	$ 1,100	$ 1,000	$ 900
Service Inventory, Gross	15,082	13,114
Accumulated Depreciation, Service Inventory	(11,992)	(11,246)
Inventory, Parts and Components, Net of Reserves	$ 3,090	$ 1,868

Deferred Revenue (Details)

Deferred Revenue (Details) $ in Thousands	Dec. 31, 2015USD ($)Customers	Dec. 31, 2014USD ($)
Deferred Revenue Arrangement [Line Items]
Deferred Revenue	$ 120,037	$ 113,498
Less long-term deferred revenue	(33,306)	(47,588)
Deferred revenue in current liabilities	86,731	65,910
Deferred Product Revenue [Member]
Deferred Revenue Arrangement [Line Items]
Deferred Revenue	22,215	21,152
Deferred Service Revenue [Member]
Deferred Revenue Arrangement [Line Items]
Deferred Revenue	97,822	92,346
US Government Agencies and Customers [Member]
Deferred Revenue Arrangement [Line Items]
Deferred Revenue	$ 57,700	$ 63,800
Deferred Revenue [Member] | Non US Government Customers [Member]
Deferred Revenue Arrangement [Line Items]
Concentration Risk, Number of Customers | Customers	0
Deferred Revenue Maximum Percentage	10.00%

Commitments and Contingencies68

Commitments and Contingencies (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Long-term Purchase Commitment [Line Items]
Research and Development Expense	$ 29,281	$ 24,989	$ 20,106	$ 22,187	$ 24,735	$ 22,503	$ 24,189	$ 22,621	$ 96,563	$ 94,048	$ 87,728
Operating Leases, Rent Expense, Net									5,900	5,200	5,300
Operating Leases, Future Minimum Payments Due, Next Twelve Months	5,484								5,484
Operating Leases, Future Minimum Payments, Due in Two Years	5,149								5,149
Operating Leases, Future Minimum Payments, Due in Three Years	4,939								4,939
Operating Leases, Future Minimum Payments, Due in Four Years	4,668								4,668
Operating Leases, Future Minimum Payments, Due in Five Years	3,391								3,391
Operating Leases, Future Minimum Payments, Due Thereafter	12,519								12,519
Operating Leases, Future Minimum Payments Due	36,150								36,150
Other Commitment	15,975								15,975
Research and Development Arrangement [Member]
Long-term Purchase Commitment [Line Items]
Research and Development Expense									14,300	$ 12,200	$ 9,300
Other Commitment, Due in Next Twelve Months	15,567								15,567
Other Commitment, Due in Second Year	233								233
Other Commitment, Due in Third Year	150								150
Other Commitment, Due in Fourth Year	25								25
Other Commitment, Due in Fifth Year	0								0
Other Commitment, Due after Fifth Year	$ 0								$ 0

Income Taxes Narrative (Details

Income Taxes Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Extraordinary Items, Noncontrolling Interest [Abstract]
United States	$ 38,362	$ 5,710	$ 17,467
International	4,415	3,987	3,562
Income before income taxes	42,777	9,697	21,029
Operating Loss Carryforwards [Line Items]
Deferred tax liabilities noncurrent	9,400	18,319
Income tax benefit (expense)	(15,240)	52,626	11,194
Change in amount of deferred tax assets	700	67,700	4,700
Three year cumulative U.S. pre-tax income		184,800
Three year cumulative U.S. pre-tax income, excluding impact of sale of interconnect hardware development program		51,100
Share-based compensation adjustment	0	0	(8,419)
Undistributed earnings of foreign subsidiaries	9,200
Cash and cash equivalents	266,660	112,633	192,633	$ 253,065
Other Noncurrent Liabilities [Member]
Operating Loss Carryforwards [Line Items]
Deferred tax liabilities noncurrent	200
Foreign Subsidiaries
Operating Loss Carryforwards [Line Items]
Cash and cash equivalents	12,900
Research Tax Credit Carryforward
Operating Loss Carryforwards [Line Items]
Tax credit carryforwards	23,000
Domestic Tax Authority
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards	76,200
Stock based income tax deductions in excess of amounts recognized	47,400
Change in amount of deferred tax assets		$ 55,700	$ 13,500
Domestic Tax Authority | Internal Revenue Service (IRS) [Member]
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards	25,600
Maximum utilization per year, of net operating loss carryforward	4,300
Foreign Tax Authority
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards	$ 6,100

Income Taxes Tax Provision (Det

Income Taxes Tax Provision (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Current provision (benefit):
Federal	$ 725	$ 230	$ 484
State	1,389	(392)	696
Foreign	1,023	740	801
Total current provision	3,137	578	1,981
Deferred provision (benefit):
Federal	12,198	(53,242)	(13,160)
State	(52)	(885)	(327)
Foreign	(43)	923	312
Total deferred provision (benefit)	12,103	(53,204)	(13,175)
Total provision (benefit) for income taxes	$ 15,240	$ (52,626)	$ (11,194)

Income Taxes Reconciliation of

Income Taxes Reconciliation of Statutory Federal Tax Rate (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Tax Expense (Benefit), Continuing Operations, Income Tax Reconciliation [Abstract]
Income tax provision at statutory rate	$ 14,972	$ 3,394	$ 7,360
State taxes, net of federal benefit	897	(217)	369
Foreign income taxes	(12)	284	(749)
Share-based compensation adjustment	0	0	(8,419)
Deemed dividends for U.S. income tax purposes	407	492	477
Nondeductible expenses	283	337	208
Disallowed compensation	455	(116)	19
Research and development tax credit	(1,733)	(1,140)	(5,736)
Effect of change in valuation allowance on deferred tax assets	(29)	(55,660)	(4,723)
Total provision (benefit) for income taxes	$ 15,240	$ (52,626)	$ (11,194)

Income Taxes Deferred Tax Asset

Income Taxes Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Deferred Tax Assets, Net [Abstract]
Inventory	$ 3,930	$ 5,840
Accrued compensation	1,213	681
Deferred revenue	18,372	18,186
Net operating loss carryforwards	2,636	12,981
Research and experimentation credit carryforwards	16,264	0
Other	4,303	1,261
Gross current deferred tax assets	46,718	38,949
Valuation allowance	(2,995)	(2,039)
Current deferred tax assets	43,723	36,910
Other	(5,095)	(837)
Current deferred tax liabilities	(5,095)	(837)
Net current deferred tax assets	38,628	36,073
Property and equipment	7,510	11,555
Research and experimentation credit carryforwards	9,528	24,596
Net operating loss carryforwards	14,523	21,511
Goodwill	125	203
Share-based compensation	5,976	5,000
Other	4,084	4,967
Gross long-term deferred tax assets	41,746	67,832
Valuation allowance	(6,492)	(8,099)
Long-term deferred tax assets	35,254	59,733
Investment in sales-type lease, net	(7,611)	(14,321)
Intangible assets	(512)	(1,215)
Other	(1,277)	(2,783)
Long-term deferred tax liabilities	(9,400)	(18,319)
Net long-term deferred tax asset	$ 25,854	$ 41,414

Income Taxes Unrecognized Tax B

Income Taxes Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Tax Disclosure [Abstract]
Unrecognized Tax Benefits, Increase Resulting from Prior Period Tax Positions	$ 151	$ 5,059
Balance of unrecognized tax benefits that if recognized would affect the effective tax rate	6,200
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Balance at December 31,	5,630	202	$ 470
Increase related to prior year income tax positions			(268)
Decrease related to prior year income tax positions	433	369
Balance at December 31,	$ 6,214	$ 5,630	$ 202

Credit Facilities (Details)

Credit Facilities (Details) - USD ($)	Jan. 07, 2016	Dec. 31, 2015	Oct. 01, 2012
Line of Credit Facility [Line Items]
Letters of Credit Outstanding, Amount		$ 5,800,000
Restricted Cash and Cash Equivalents		3,300,000
Wells Fargo Bank
Line of Credit Facility [Line Items]
Amount of credit facility		10,000,000	$ 10,000,000
Draws on line of credit		0
Line of credit, amount outstanding		0
Silicon Valley Bank
Line of Credit Facility [Line Items]
Amount of credit facility		$ 11,000,000
Subsequent Event [Member] | Wells Fargo Bank
Line of Credit Facility [Line Items]
Amount of credit facility	$ 50,000,000
Debt instrument, term	2 years

Shareholders' Equity Assumption

Shareholders' Equity Assumptions (Details) - $ / shares	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Share-based Compensation [Abstract]
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate, Minimum	1.31%	1.22%	0.98%
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Dividend Rate	0.00%	0.00%	0.00%
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate, Minimum	50.55%	52.43%	50.45%
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Term	4 years	4 years	4 years
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value	$ 11.23	$ 11.16	$ 8.22
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Average Period Options will be Exercised after Vesting	2 years
Estimated Forfeiture Rate for Stock Option Grants	8.00%	8.30%	10.00%

Shareholders' Equity Option Act

Shareholders' Equity Option Activity (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	1,930,990	2,078,069	2,293,505
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross	307,450	323,900	346,360
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period	(229,118)	(411,352)	(495,221)
Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures and Expirations in Period	(60,847)	(59,627)	(66,575)
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	1,948,475	1,930,990	2,078,069
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price	$ 12.34	$ 9.29	$ 7.31
Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price	27.86	26.92	20.65
Share-based Compensation Arrangements by Share-based Payment Award, Options, Exercises in Period, Weighted Average Exercise Price	9.99	7.50	6.38
Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures and Expirations in Period, Weighted Average Exercise Price	20	18.45	21.97
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price	$ 14.83	$ 12.34	$ 9.29
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number	1,357,512
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price	$ 10.40
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant	1,791,731
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term	6 years 3 months 18 days
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Remaining Contractual Term	5 years 3 months 18 days
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value	$ 34.4
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Intrinsic Value	29.9
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Intrinsic Value	$ 5	$ 10.2	$ 7.9

Shareholders' Equity Exercise P

Shareholders' Equity Exercise Price Range (Details)	12 Months Ended
	Dec. 31, 2015$ / sharesshares
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Number of Outstanding Options | shares	1,948,475
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Outstanding Options, Weighted Average Remaining Contractual Term	6 years 3 months 18 days
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Outstanding Options, Weighted Average Exercise Price	$ 14.83
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Number of Exercisable Options | shares	1,357,512
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Exercisable Options, Weighted Average Exercise Price	$ 10.40
Lower Range	0
Upper Range	$ 34.52
Range of Exercise Prices, Range One [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Number of Outstanding Options | shares	879,263
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Outstanding Options, Weighted Average Remaining Contractual Term	4 years 2 months 12 days
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Outstanding Options, Weighted Average Exercise Price	$ 5.67
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Number of Exercisable Options | shares	879,179
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Exercisable Options, Weighted Average Exercise Price	$ 5.67
Lower Range	0
Upper Range	$ 10
Range of Exercise Prices, Range Two [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Number of Outstanding Options | shares	412,016
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Outstanding Options, Weighted Average Remaining Contractual Term	6 years 10 months 24 days
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Outstanding Options, Weighted Average Exercise Price	$ 15.21
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Number of Exercisable Options | shares	293,735
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Exercisable Options, Weighted Average Exercise Price	$ 14.51
Lower Range	10.01
Upper Range	$ 20
Range of Exercise Prices, Range Three [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Number of Outstanding Options | shares	367,794
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Outstanding Options, Weighted Average Remaining Contractual Term	8 years 6 months
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Outstanding Options, Weighted Average Exercise Price	$ 25.44
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Number of Exercisable Options | shares	115,590
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Exercisable Options, Weighted Average Exercise Price	$ 24.87
Lower Range	20.01
Upper Range	$ 27
Range of Exercise Prices, Range Four [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Number of Outstanding Options | shares	289,402
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Outstanding Options, Weighted Average Remaining Contractual Term	9 years
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Outstanding Options, Weighted Average Exercise Price	$ 28.60
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Number of Exercisable Options | shares	69,008
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Exercisable Options, Weighted Average Exercise Price	$ 28.96
Lower Range	27.01
Upper Range	$ 34.52

Shareholders' Equity Restricted

Shareholders' Equity Restricted Stock (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock Issued During Period, Value, Share-based Compensation, Gross	$ 2,289	$ 3,086	$ 3,161
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period	4 years
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock Issued During Period, Value, Share-based Compensation, Gross	$ 1,400	13,300	15,800
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Fair Value	$ 14,200	$ 11,900	$ 14,000
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock Issued During Period, Shares, Restricted Stock Award, Gross	45,175	463,734	755,979
Estimated Forfeiture Rate for Restricted Stock	8.00%	6.30%
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number	1,850,602	2,221,700	2,202,738
Shares issued during the period (shares)	45,175	463,734	755,979
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period	(267,998)	(411,653)	(75,437)
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period	(525,836)	(423,179)	(661,580)
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number	1,101,943	1,850,602	2,221,700
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value	$ 17.68	$ 13.97	$ 9.27
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value	30.44	28.74	20.93
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value	17.14	16.80	14.48
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value	15.64	11.14	6.22
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value	$ 19.31	$ 17.68	$ 13.97
Restricted Stock [Member] | Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number	817,000	1,094,000	737,000
Shares issued during the period (shares)	0	0	429,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period	(219,000)	(277,000)	(72,000)
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period	(12,500)	0	0
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number	585,500	817,000	1,094,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value	$ 15.41	$ 15.94	$ 12.90
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value	0	0	21
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value	15.60	17.49	14.88
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value	28.20	0	0
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value	$ 15.07	$ 15.41	$ 15.94
Restricted Stock [Member] | Time-vesting Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number	1,033,602	1,127,700	1,465,738
Shares issued during the period (shares)	45,175	463,734	326,979
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period	(48,998)	(134,653)	(3,437)
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period	(513,336)	(423,179)	(661,580)
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number	516,443	1,033,602	1,127,700
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value	$ 19.48	$ 12.05	$ 7.44
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value	30.44	28.74	20.83
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value	24	15.39	5.92
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value	15.34	11.14	6.22
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value	$ 24.12	$ 19.48	$ 12.05
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock Issued During Period, Shares, Restricted Stock Award, Gross	984,850
Stock Issued During Period, Value, Share-based Compensation, Gross	$ 29,500
Estimated Forfeiture Rate for Restricted Stock	8.00%
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number	0	0
Shares issued during the period (shares)	984,850	0	0
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period	(79,100)
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period	0
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number	905,750	0	0
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value	$ 0
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value	29.97
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value	30.11
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value	0
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value	$ 29.95	$ 0
Restricted Stock Units (RSUs) [Member] | Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number	0
Shares issued during the period (shares)	699,300
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period	(66,600)
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period	0
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number	632,700	0
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value	$ 0
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value	30.04
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value	30.04
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value	0
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value	$ 30.04	$ 0
Restricted Stock Units (RSUs) [Member] | Time-vesting Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number	0
Shares issued during the period (shares)	285,550
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period	(12,500)
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period	0
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number	273,050	0
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value	$ 0
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value	29.78
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value	30.48
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value	0
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value	$ 29.75	$ 0
NonEmployee Director [Member] | Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period	1 year
Officers and Key Employees [Member] | Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period	4 years

Shareholders' Equity Expense (D

Shareholders' Equity Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Gross share-based compensation, total	$ 11,353	$ 10,364	$ 7,239
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized	44,800
Monetary Effects Of Performance Vesting Restricted Stock Subject To Performance Measures Which Are Currently Not Considered Probable	27,800
Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Excluding Performance Vesting Restricted Stock	$ 17,000
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition	2 years 8 months 12 days
Cost of product revenue
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Gross share-based compensation, total	$ 254	229	135
Cost of service revenue
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Gross share-based compensation, total	276	255	229
Research and development
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Gross share-based compensation, total	3,770	2,721	1,480
Sales and marketing
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Gross share-based compensation, total	3,047	3,152	2,230
General and administrative
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Gross share-based compensation, total	$ 4,006	$ 4,007	$ 3,165

Shareholders' Equity ESPP (Deta

Shareholders' Equity ESPP (Details) - shares	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock Issued Under Employee Stock Purchase Plan	1,070,343	1,043,228	1,022,610
Employee Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized	1,750,000
Share-based Compensation Arrangement by Share-based Payment Award, Maximum Employee Subscription Rate	15.00%
Share-based Compensation Arrangement by Share-based Payment Award, Percentage of Market Price	95.00%

Shareholders' Equity Narrative

Shareholders' Equity Narrative (Details)	12 Months Ended
	Dec. 31, 2015equity_incentive_plan$ / sharesshares	Dec. 31, 2014$ / sharesshares
Share-based Compensation [Abstract]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period	4 years
Preferred Stock, Shares Authorized	5,000,000	5,000,000
Preferred Stock, Shares Outstanding	0	0
Number of equity incentive plans (equity_incentive_plan) | equity_incentive_plan	1
Common Stock, Shares Authorized	75,000,000	75,000,000
Common Stock, Par or Stated Value Per Share | $ / shares	$ 0.01	$ 0.01
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period	10 years

Benefit Plans (Details)

Benefit Plans (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
United States Pension Plan of US Entity
Defered Compensation Arrangement with Individual [Line Items]
Company match expense	$ 2.6	$ 1.6	$ 1.2
Foreign Pension Plans, Defined Benefit
Defered Compensation Arrangement with Individual [Line Items]
Projected benefit	2.1	2.3
Funded status of plan	$ 0.2	$ 0.2

Segment Information Business Se

Segment Information Business Segment (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Information of Operating Segments
Revenue:	$ 267,471	$ 191,413	$ 186,161	$ 79,644	$ 261,943	$ 159,406	$ 85,147	$ 55,110	$ 724,689	$ 561,606	$ 525,749
Gross Profit:	$ 86,180	$ 65,882	$ 49,585	$ 24,036	$ 88,943	$ 48,530	$ 29,004	$ 17,937	225,683	184,414	184,326
Supercomputing
Information of Operating Segments
Revenue:									581,733	459,729	434,133
Gross Profit:									177,048	146,565	143,440
Storage and Data Management
Information of Operating Segments
Revenue:									112,862	84,412	76,955
Gross Profit:									37,181	31,572	31,403
Maintenance & Support
Information of Operating Segments
Revenue:									97,091	86,573	77,817
Gross Profit:									41,487	38,819	38,476
Engineering Services and Other
Information of Operating Segments
Revenue:									30,094	17,465	14,661
Gross Profit:									11,454	6,277	9,483
Elimination of inter-segment revenue
Information of Operating Segments
Revenue:									(97,091)	(86,573)	(77,817)
Gross Profit:									$ (41,487)	$ (38,819)	$ (38,476)

Segment Information Geographic

Segment Information Geographic Segment (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Revenues from External Customers and Long-Lived Assets [Line Items]
Product revenue	$ 601,294	$ 460,748	$ 436,330
Service revenue	123,395	100,858	89,419
Long-lived assets	78,958	95,660	65,056
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Product revenue	373,494	253,930	297,583
Service revenue	88,956	72,434	62,072
Long-lived assets	55,227	58,868	58,910
All Other Countries
Revenues from External Customers and Long-Lived Assets [Line Items]
Product revenue	227,800	206,818	138,747
Service revenue	34,439	28,424	27,347
Long-lived assets	$ 23,731	$ 36,792	$ 6,146

Segment Information Long-lived

Segment Information Long-lived assets (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Segment Reporting [Abstract]
Long-term investment in sales-type lease, net	$ 18,317	$ 31,089

Segment Information Narrative (

Segment Information Narrative (Details) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015USD ($)Customers	Sep. 30, 2015USD ($)	Jun. 30, 2015USD ($)	Mar. 31, 2015USD ($)	Dec. 31, 2014USD ($)Customers	Sep. 30, 2014USD ($)	Jun. 30, 2014USD ($)	Mar. 31, 2014USD ($)	Dec. 31, 2015USD ($)Customers	Dec. 31, 2014USD ($)Customers	Dec. 31, 2013USD ($)Customers
Revenue, Major Customer [Line Items]
Long-term investment in sales-type lease, net	$ (18,317)				$ (31,089)				$ (18,317)	$ (31,089)
Revenue	$ 267,471	$ 191,413	$ 186,161	$ 79,644	$ 261,943	$ 159,406	$ 85,147	$ 55,110	724,689	561,606	$ 525,749
US Government Agencies and Customers [Member]
Revenue, Major Customer [Line Items]
Revenue									$ 338,500	$ 272,000	$ 266,100
Non US Government Customers [Member]
Revenue, Major Customer [Line Items]
Percentage of total revenue from customers that individually accounted for more than 10% of total revenue									10.00%		11.00%
Revenue
Revenue, Major Customer [Line Items]
Number of foreign countries that individually accounted for more than 10% of total revenue | Customers					0					0	1
All Other Countries | Revenue
Revenue, Major Customer [Line Items]
Number of foreign countries that individually accounted for more than 10% of total revenue | Customers	0								0
Percentage of total revenue from customers that individually accounted for more than 10% of total revenue									10.00%
UK and Germany [Member] | Revenue
Revenue, Major Customer [Line Items]
Percentage of total revenue from customers that individually accounted for more than 10% of total revenue										23.00%

Research and Development (Detai

Research and Development (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Research and Development [Abstract]
Gross research and development expenses									$ 126,060	$ 104,797	$ 92,469
Less: Amounts included in cost of revenue									(16,515)	(7,713)	(3,741)
Less: Reimbursed research and development (excludes amounts in revenue)									(12,982)	(3,036)	(1,000)
Net research and development expenses	$ 29,281	$ 24,989	$ 20,106	$ 22,187	$ 24,735	$ 22,503	$ 24,189	$ 22,621	$ 96,563	$ 94,048	$ 87,728

Interest Income (Expense) (Deta

Interest Income (Expense) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Other Income and Expenses [Abstract]
Interest income	$ 1,465	$ 643	$ 894
Interest expense	(57)	(137)	(137)
Interest Income (Expense), Net	$ 1,408	$ 506	$ 757

Quarterly Data (Unaudited) (Det

Quarterly Data (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended																12 Months Ended
	Dec. 31, 2015		Sep. 30, 2015		Jun. 30, 2015		Mar. 31, 2015		Dec. 31, 2014		Sep. 30, 2014		Jun. 30, 2014		Mar. 31, 2014		Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Selected Quarterly Financial Information [Abstract]
Revenue	$ 267,471		$ 191,413		$ 186,161		$ 79,644		$ 261,943		$ 159,406		$ 85,147		$ 55,110		$ 724,689	$ 561,606	$ 525,749
Cost of revenue	181,291		125,531		136,576		55,608		173,000		110,876		56,143		37,173		499,006	377,192	341,423
Gross profit	86,180		65,882		49,585		24,036		88,943		48,530		29,004		17,937		225,683	184,414	184,326
Research and development, net	29,281		24,989		20,106		22,187		24,735		22,503		24,189		22,621		96,563	94,048	87,728
Sales and marketing	18,054		16,132		13,412		12,552		17,942		14,808		13,259		11,776		60,150	57,785	51,345
General and administrative	8,662		6,729		6,435		6,140		6,839		5,813		5,316		5,413		27,966	23,381	23,603
Net income	$ 20,295	[1]	$ 10,855	[1]	$ 5,781	[1]	$ (9,394)	[1]	$ 74,638	[1]	$ 7,371	[1]	$ (6,748)	[1]	$ (12,938)	[1]	$ 27,537	$ 62,323	$ 32,223
Net income (loss) per common share, basic	$ 0.51		$ 0.28		$ 0.15		$ (0.24)		$ 1.92		$ 0.19		$ (0.18)		$ (0.34)		$ 0.70	$ 1.61	$ 0.85
Net income (loss) per common share, diluted	$ 0.50		$ 0.27		$ 0.14		$ (0.24)		$ 1.84		$ 0.18		$ (0.18)		$ (0.34)		$ 0.68	$ 1.54	$ 0.81
[1]	The fourth quarter of 2014 includes the impact of the reduction of substantially all of the valuation allowance held against the Company’s U.S. deferred tax assets.

Subsequent Events (Details)

Subsequent Events (Details) - Wells Fargo Bank - USD ($)	Jan. 07, 2016	Dec. 31, 2015	Oct. 01, 2012
Subsequent Event [Line Items]
Amount of credit facility		$ 10,000,000	$ 10,000,000
Subsequent Event [Member]
Subsequent Event [Line Items]
Amount of credit facility	$ 50,000,000
Line of credit facility, unused capacity, commitment fee percentage	0.18%
Subsequent Event [Member] | London Interbank Offered Rate (LIBOR) [Member]
Subsequent Event [Line Items]
Debt instrument, basis spread on variable rate	1.25%

Schedule II - Valuation and Q91

Schedule II - Valuation and Qualifying Accounts (Details) - Allowance for Trade Receivables - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period		$ 97	$ 157	$ 5
Charge/(Benefit) to Expense		0	22	179
Deductions	[1]	(78)	(82)	(27)
Balance at End of Period		$ 19	$ 97	$ 157
[1]	Deductions represent uncollectible accounts written off, net of recoveries.