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Document and Entity Information - USD ($)	12 Months Ended
Document and Entity Information - USD ($)	Dec. 31, 2016	Mar. 13, 2017	Jun. 30, 2016
Document and Entity Information
Entity Registrant Name	AXCELIS TECHNOLOGIES INC
Entity Central Index Key	0001113232
Document Type	10-K
Document Period End Date	Dec. 31, 2016
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Accelerated Filer
Entity Public Float			$ 310,378,330
Entity Common Stock, Shares Outstanding		29,917,059
Document Fiscal Year Focus	2016
Document Fiscal Period Focus	FY

Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Revenue:
Product	$ 244,295	$ 278,875	$ 179,246
Services	22,685	22,620	23,805
Total revenue	266,980	301,495	203,051
Cost of revenue:
Product	149,007	181,060	113,285
Services	18,375	18,729	19,602
Total cost of revenue	167,382	199,789	132,887
Gross profit	99,598	101,706	70,164
Operating expenses:
Research and development	34,402	32,586	33,533
Sales and marketing	23,839	23,325	20,713
General and administrative	24,452	25,059	23,958
Restructuring charges	282	18	2,621
Total operating expenses	82,975	80,988	80,825
Income (loss) from operations	16,623	20,718	(10,661)
Other (expense) income:
Interest income	238	64	32
Interest expense	(5,073)	(4,976)	(1,069)
Other, net	(764)	(601)	1,531
Total other (expense) income	(5,599)	(5,513)	494
Income (loss) before income taxes	11,024	15,205	(10,167)
Income tax provision	23	527	1,099
Net income (loss)	$ 11,001	$ 14,678	$ (11,266)
Net income (loss) per share:
Basic (in dollars per share)	$ 0.38	$ 0.51	$ (0.40)
Diluted (in dollars per share)	$ 0.36	$ 0.49	$ (0.40)
Shares used in computing net income (loss) per share:
Basic weighted average common shares	29,195	28,595	27,862
Diluted weighted average common shares	30,947	30,229	27,862

Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Consolidated Statements of Comprehensive Income (Loss)
Net income (loss)	$ 11,001	$ 14,678	$ (11,266)
Other comprehensive (loss):
Foreign currency translation adjustments	(847)	(2,664)	(4,150)
Amortization of actuarial gains/losses and other adjustments from pension plan	(1)	(43)	(313)
Total other comprehensive (loss)	(848)	(2,707)	(4,463)
Comprehensive income (loss)	$ 10,153	$ 11,971	$ (15,729)

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Current assets:
Cash and cash equivalents	$ 70,791	$ 78,889
Accounts receivable, net	50,573	36,868
Inventories, net	113,853	109,408
Prepaid expenses and other current assets	5,512	4,792
Total current assets	240,729	229,957
Property, plant and equipment, net	30,840	30,031
Long-term restricted cash	6,864	6,936
Other assets	23,798	14,860
Total assets	302,231	281,784
Current liabilities:
Accounts payable	24,996	19,849
Accrued compensation	5,142	9,059
Warranty	2,426	3,363
Income taxes	240	143
Deferred revenue	10,335	7,863
Other current liabilities	4,592	4,091
Total current liabilities	47,731	44,368
Sale leaseback obligation	47,586	47,586
Long-term deferred revenue	674	679
Other long-term liabilities	4,785	5,387
Total liabilities	100,776	98,020
Commitments and contingencies (Note 17)
Stockholders' equity
Preferred stock, $0.001 par value, 30,000 shares authorized; none issued or outstanding
Common stock, $0.001 par value, 75,000 shares authorized; 29,518 shares issued and outstanding at December 31, 2016; 29,025 shares issued and 28,995 shares outstanding at December 31, 2015	30	29
Additional paid-in capital	535,408	529,089
Treasury stock, at cost, no shares at December 31, 2016 and 30 shares at December 31, 2015		(1,218)
Accumulated deficit	(331,704)	(342,705)
Accumulated other comprehensive loss	(2,279)	(1,431)
Total stockholders' equity	201,455	183,764
Total liabilities and stockholders' equity	$ 302,231	$ 281,784

Consolidated Balance Sheets (Parenthetical) - $ / shares shares in Thousands	Dec. 31, 2016	Dec. 31, 2015
Consolidated Balance Sheets
Preferred stock, par value (in dollars per share)	$ 0.001	$ 0.001
Preferred stock, shares authorized	30,000	30,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized	75,000	75,000
Common stock, shares issued	29,518	29,025
Common stock, shares outstanding	29,518	28,995
Treasury stock, shares	0	30

Consolidated Statements of Stockholders' Equity - USD ($) shares in Thousands, $ in Thousands	Common Stock	Additional Paid-in Capital	Treasury Stock	Accumulated Deficit	Accumulated Other Comprehensive Income (Loss)	Total
Balance at Dec. 31, 2013	$ 27	$ 511,075	$ (1,218)	$ (346,117)	$ 5,739	$ 169,506
Balance (in shares) at Dec. 31, 2013	27,556
Increase (Decrease) in Stockholders' Equity
Net income (loss)				(11,266)		(11,266)
Foreign currency translation adjustments					(4,150)	(4,150)
Amortization of actuarial gains/losses and other adjustments from pension plan					(313)	(313)
Exercise of stock options	$ 1	2,894				2,895
Exercise of stock options (in shares)	605
Issuance of shares under Employee Stock Purchase Plan		446				446
Issuance of shares under Employee Stock Purchase Plan (in shares)	50
Issuance of restricted common shares		(7)				(7)
Issuance of restricted common shares (in shares)	2
Stock-based compensation expense		4,745				4,745
Balance at Dec. 31, 2014	$ 28	519,153	(1,218)	(357,383)	1,276	161,856
Balance (in shares) at Dec. 31, 2014	28,213
Increase (Decrease) in Stockholders' Equity
Net income (loss)				14,678		14,678
Foreign currency translation adjustments					(2,664)	(2,664)
Amortization of actuarial gains/losses and other adjustments from pension plan					(43)	(43)
Exercise of stock options	$ 1	3,920				3,921
Exercise of stock options (in shares)	759
Issuance of shares under Employee Stock Purchase Plan		441				441
Issuance of shares under Employee Stock Purchase Plan (in shares)	47
Issuance of restricted common shares		(7)				(7)
Issuance of restricted common shares (in shares)	7
Stock-based compensation expense		5,582				5,582
Balance at Dec. 31, 2015	$ 29	529,089	(1,218)	(342,705)	(1,431)	183,764
Balance (in shares) at Dec. 31, 2015	29,026
Increase (Decrease) in Stockholders' Equity
Net income (loss)				11,001		11,001
Foreign currency translation adjustments					(847)	(847)
Amortization of actuarial gains/losses and other adjustments from pension plan					(1)	(1)
Exercise of stock options	$ 1	2,237				2,238
Exercise of stock options (in shares)	392
Issuance of shares under Employee Stock Purchase Plan		325				325
Issuance of shares under Employee Stock Purchase Plan (in shares)	22
Issuance of restricted common shares		(11)				(11)
Issuance of restricted common shares (in shares)	108
Treasury shares returned to authorized, Value		(1,218)	$ 1,218			0
Treasury shares returned to authorized, Shares	(30)
Reverse stock split issuance costs		(145)				(145)
Stock-based compensation expense		5,131				5,131
Balance at Dec. 31, 2016	$ 30	$ 535,408		$ (331,704)	$ (2,279)	$ 201,455
Balance (in shares) at Dec. 31, 2016	29,518

Consolidated Statements of Cash Flow $ in Thousands	12 Months Ended
Consolidated Statements of Cash Flow $ in Thousands	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)
Cash flows from operating activities
Net income	$ 11,001	$ 14,678	$ (11,266)
Adjustments to reconcile net income to net cash (used in) provided by operating activities:
Depreciation and amortization	4,258	4,869	4,589
Gain on sale of equipment	(248)
Deferred taxes	519	779	1,266
Stock-based compensation expense	5,179	5,575	4,812
Provision for doubtful accounts	106
Provision for excess and obsolete inventory	1,051	1,721	1,817
Changes in operating assets & liabilities:
Accounts receivable	(14,135)	5,171	(7,069)
Inventories	(6,572)	(15,938)	(12,280)
Prepaid expenses and other current assets	(1,056)	640	(1,384)
Accounts payable and other current liabilities	799	5,997	772
Deferred revenue	2,467	1,360	2,577
Income taxes	102	(46)	(212)
Other assets and liabilities	(12,270)	(6,547)	333
Net cash (used in) provided by operating activities	(8,799)	18,259	(16,045)
Cash flows from investing activities
Proceeds from sale of equipment	270
Expenditures for property, plant, and equipment	(2,506)	(1,830)	(896)
Net cash used in investing activities	(2,236)	(1,830)	(896)
Cash flows from financing activities
Decrease in restricted cash	72	(6,111)
Financing fees and other expenses	(146)	(847)	(115)
Proceeds from exercise of stock options	2,227	3,921	2,895
Proceeds from Employee Stock Purchase Plan	277	441	446
Principal payments on sale leaseback obligation		(392)
Proceeds from financing obligations		48,940
Principal payments on Term Loan		(14,530)	(470)
Net cash provided by financing activities	2,430	31,422	2,756
Effect of exchange rate changes on cash and cash equivalents	507	285	(1,352)
Net (decrease) increase in cash and cash equivalents	(8,098)	48,136	(15,537)
Cash and cash equivalents at beginning of period	78,889	30,753	46,290
Cash and cash equivalents at end of period	70,791	78,889	30,753
Supplemental disclosure of cash flow information
Cash paid for Income taxes	525	669	931
Cash paid for Interest	4,815	3,985	832
Supplemental disclosure of total cash, cash equivalents and restricted cash:
Cash and cash equivalents at end of period	70,791	78,889	30,753
Restricted cash at end of period	6,864	6,936	825
Total cash, cash equivalents and restricted cash at end of period	$ 77,655	$ 85,825	$ 31,578

Nature of Business	12 Months Ended
Nature of Business	Dec. 31, 2016
Nature of Business
Nature of Business	Note 1. Nature of Business Axcelis Technologies, Inc. (“Axcelis” or the “Company”) was incorporated in Delaware in 1995, and is a worldwide producer of ion implantation and other processing equipment used in the fabrication of semiconductor chips in the United States, Europe and Asia. In addition, the Company provides extensive aftermarket service and support, including spare parts, equipment upgrades, used equipment and maintenance services to the semiconductor industry.

Summary of Significant Accounting Policies

12 Months Ended

Dec. 31, 2016

Summary of Significant Accounting Policies

Summary of Significant Accounting Policies

Note 2. Summary of Significant Accounting Policies

The accompanying consolidated financial statements reflect the application of certain significant accounting policies as described in this note and elsewhere in the footnotes.

(a) Basis of Presentation

The accompanying consolidated financial statements include the accounts of the Company and its wholly‑owned, controlled subsidiaries. All intercompany balances and transactions have been eliminated in consolidation.

Events occurring subsequent to December 31, 2016 have been evaluated for potential recognition or disclosure in the consolidated financial statements.

(b) Use of Estimates

The preparation of these consolidated financial statements in conformity with accounting principles generally accepted in the United States of America requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities at the dates of the financial statements and the reported amounts of revenue and expenses during the reporting periods. On an ongoing basis, the Company evaluates its estimates and judgments, including those related to revenue recognition, the realizable value of inventories, valuing stock-based compensation instruments and valuation allowances for deferred tax assets. Actual amounts could differ from these estimates. Changes in estimates are recorded in the period in which they become known.

The functional currency for substantially all operations outside the United States is the local currency. Financial statements for these operations are translated into United States dollars at year‑end rates as to assets and liabilities and average exchange rates during the year as to revenue and expenses. The resulting translation adjustments are recorded in stockholders’ equity as an element of accumulated other comprehensive income (loss). Foreign currency transaction gains and losses are included in other income (expense) in the Consolidated Statements of Operations.

For the year ended December 31, 2016 the Company had $0.6 million in foreign exchange losses. For the year ended December 31, 2015 the Company did not have any material foreign exchange gains or losses. For the year ended December 31, 2014, the Company realized $1.8 million of foreign exchange gains.

(d) Cash and Cash Equivalents

Cash and cash equivalents consist of cash on hand and highly liquid investments with original maturities of ninety days or less. Cash equivalents consist primarily of money market securities and certificates of deposit. Cash equivalents are carried on the balance sheet at fair market value.

(e) Inventories

Inventories are carried at lower of cost, determined using the first‑in, first‑out (“FIFO”) method, or market. The Company periodically reviews its inventories and makes provisions as necessary for estimated obsolescence or damaged goods to ensure values approximate lower of cost or market. The amount of such markdowns is equal to the difference between cost of inventory and the estimated market value based upon assumptions about future demands, selling prices, and market conditions.

The Company records an allowance for estimated excess inventory. The allowance is determined using management’s assumptions of materials usage, based on estimates of demand and market conditions. If actual market conditions become less favorable than those projected by management, additional inventory write‑downs may be required.

(f) Property, Plant and Equipment

Property, plant and equipment are stated at cost, less accumulated depreciation and amortization.

Depreciation and amortization are recorded using the straight‑line method over the estimated useful lives of the related assets as follows:


Asset Classification	Estimated Useful Life
Land and buildings (under lease)		Lesser of the lease term or estimated useful life of the asset
Machinery and equipment		3 to 10 years

On January 30, 2015, the Company sold its corporate headquarters facility. As part of this sale, the Company also entered into a 22-year lease agreement. The Company accounted for the sale leaseback transaction as a financing arrangement for financial reporting purposes. The Company retained the historical costs of the property and the related accumulated depreciation on its financial books within property, plant and equipment and will continue to depreciate the property for financial reporting purposes over the lesser of its remaining useful life or its initial lease term of 22 years.

Repairs and maintenance costs are expensed as incurred. Expenditures for renewals and betterments are capitalized.

(g) Impairment of Long‑Lived Assets

The Company records impairment losses on long-lived assets when events and circumstances indicate that these assets might not be recoverable. Recoverability is measured by a comparison of the assets’ carrying amount to their expected future undiscounted net cash flows. If such assets are considered to be impaired, the impairment is measured based on the amount by which the carrying value exceeds its fair value.

The Company did not have any indicators of impairment during the period ending December 31, 2016. The Company did not record an impairment charge in the years ended December 31, 2016, 2015, or 2014.

Actual performance could be materially different from our current forecasts, which could impact estimates of undiscounted cash flows and may result in the impairment of the carrying amount of the long-lived assets in the future. This could be caused by strategic decisions made in response to economic and competitive conditions, the impact of the economic environment on our customer base, or a material adverse change in the Company’s relationships with significant customers.

(h) Concentration of Risk and Off‑Balance Sheet Risk

Financial instruments that potentially subject the Company to concentrations of credit risk are principally cash equivalents and accounts receivable. The Company’s cash equivalents are principally maintained in an investment grade money‑market fund or certificates of deposit.

The Company has no significant off‑balance‑sheet risk such as exchange contracts, option contracts or other hedging arrangements.

The Company’s exposure to market risk for changes in interest rates relates primarily to cash equivalents. The primary objective of the Company’s investment activities is to preserve principal without significantly increasing risk. This is accomplished by investing in marketable high investment grade securities. The Company does not use derivative financial instruments to manage its investment portfolio and does not expect operating results or cash flows to be affected to any significant degree by any change in market interest rates.

The Company performs ongoing credit evaluations of its customers’ financial condition and generally requires no collateral to secure accounts receivable. For selected overseas sales, the Company requires customers to obtain letters of credit before product is shipped. The Company maintains an allowance for doubtful accounts based on its assessment of the collectability of accounts receivable. The Company reviews the allowance for doubtful accounts monthly. The Company does not have any off‑balance sheet credit exposure related to its customers.

The Company’s customers consist of semiconductor chip manufacturers located throughout the world and net sales to its ten largest customers accounted for 70.2%, 76.8% and 68.1% of revenue in 2016, 2015 and 2014, respectively.

For the year ended December 31, 2016, the Company had one customer representing 17.0% of total revenue. For the year ended December 31, 2015, the Company had two customers representing 29.3% and 10.5% of total revenue, respectively. For the year ended December 2014 the Company had two customers representing 17.4% and 12.3% of total revenue, respectively.

As of December 31, 2016, the Company had four customers account for 22.0%, 12.3%, 12.0% and 10.6% of consolidated accounts receivable, respectively. As of December 31, 2015, the Company had three customers account for 22.9%, 12.7% and 11.6% of consolidated accounts receivable, respectively.

Some of the components and sub‑assemblies included in the Company’s products are obtained either from a sole source or a limited group of suppliers. Disruption to the Company’s supply source, resulting either from economic conditions or other factors, could affect its ability to deliver products to its customers.

(i) Revenue Recognition

The Company’s revenue recognition policy involves significant judgment by management. The Company considers a broad array of facts and circumstances in determining when to recognize revenue, including contractual obligations to the customer, the complexity of the customer’s post‑delivery acceptance provisions, payment history, customer creditworthiness and the installation process.

The Company’s system sales transactions are made up of multiple elements, including the system itself and elements that are not delivered simultaneously with the system. These undelivered elements might include a combination of installation services, extended warranty and support and spare parts, all of which are covered generally by a single sales price.

The Company’s system revenue arrangements with multiple elements are divided into separate units of accounting if specified criteria are met, including whether the delivered element has stand‑alone value to the customer. If the criteria are met, then the consideration received is allocated among the separate units based on their relative selling price, and the revenue is recognized separately for each of the separate units.

The Company determines selling price for each unit of accounting (element) using vendor specific objective evidence (VSOE) or third‑party evidence (TPE), if they exist, otherwise, the Company uses best estimated selling price (BESP). The Company generally expects that it will not be able to establish TPE due to the nature of its products, and, as such, the Company typically will determine selling price using VSOE or BESP.

Where required, the Company determines BESP for an individual element based on consideration of both market and Company‑specific factors, including the selling price and profit margin for similar products, the cost to produce the deliverable and the anticipated margin on that deliverable and the characteristics of the markets in which the deliverable is sold.

Systems are not sold separately and VSOE or TPE is not available for the systems element. Therefore the selling price associated with systems is based on BESP. The allocated value for installation in the arrangement includes either (i) the relative selling price of the installation or (ii) the portion of the sales price that will not be received until the installation is completed (the “retention”). The selling price of elements such as extended warranty for support, spare parts and support labor is also based on BESP. For the majority of regions, the selling price of installation is based upon the fair value of the service performed, including labor, which is based upon the estimated time to complete the installation at hourly rates, and material components, both of which are sold separately, or VSOE. In regions where VSOE does not exist the Company uses BESP.

Product revenue for products which have demonstrated market acceptance, is generally recognized upon shipment provided title and risk of loss has passed to the customer, evidence of an arrangement exists, prices are contractually fixed or determinable, collectability is reasonably assured through historical collection results and regular credit evaluations, and there are no uncertainties regarding customer acceptance. Revenue from installation services is recognized at the time acceptance has occurred, as defined in the sales documentation or, for certain customers, when both acceptance has occurred and retention payment has been received. Revenue for other elements is recognized at the time products are shipped or the related services are performed.

The Company generally recognizes revenue for systems which have demonstrated market acceptance at the time of shipment because the customer’s post‑delivery acceptance provisions and installation process have been established to be routine, commercially inconsequential and perfunctory. The Company believes the risk of failure to complete a system installation is remote.

For initial shipments of systems with new technologies or in the small number of instances where the Company is unsure of meeting the customer’s specifications or obtaining customer acceptance upon shipment of the system, it will defer the recognition of systems revenue and related costs until written customer acceptance of the system is obtained. This deferral period is generally within twelve months of shipment.

Revenue related to maintenance and service contracts is recognized ratably over the duration of the contracts, or based on parts usage, where appropriate. Revenue related to service hours is recognized when the services are performed.

Product revenue includes revenue from system sales, sales of spare parts, the spare parts component of maintenance and service contracts and product upgrades. Services revenue includes the labor component of maintenance and service contract amounts charged for on‑site service personnel.

Axcelis reports revenue net of any taxes collected from customers and remitted to governmental authorities, with the collected taxes recorded as current liabilities until remitted to the relevant government authority.

(j) Shipping and Handling Costs

Shipping and handling costs are included in cost of revenue.

(k) Stock‑Based Compensation

The Company generally recognizes compensation expense for all stock-based payments to employees and directors, including grants of employee stock options, based on the grant‑date fair value of those stock‑based payments using the Black‑Scholes option pricing model, adjusted for expected forfeitures. Other valuation models may be utilized in the limited circumstances where awards with market-based vesting considerations, such as the price of the Company’s common stock, or performance based awards, are granted. Stock‑based compensation expense is recognized ratably over the requisite service period. For each stock option grant with vesting based on a combination of time, market or performance conditions, where vesting will occur if either condition is met, the related compensation costs are recognized over the shorter of the explicit service period or the derived service period.

See Note 14 for additional information relating to stock‑based compensation.

(l) Income Taxes

The Company records income taxes using the asset and liability method. Deferred income tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective income tax basis, and operating loss and tax credit carryforwards.

The Company’s consolidated financial statements contain certain deferred tax assets which have arisen primarily as a result of operating losses, as well as other temporary differences between financial and tax accounting. The Company establishes a valuation allowance if the likelihood of realization of the deferred tax assets is reduced based on an evaluation of objective verifiable evidence. Significant management judgment is required in determining the Company’s provision for income taxes, the Company’s deferred tax assets and liabilities and any valuation allowance recorded against those net deferred tax assets. The Company evaluates the weight of all available evidence to determine whether it is more likely than not that some portion or all of the net deferred income tax assets will not be realized.

Income taxes include the largest amount of tax benefit for an uncertain tax position that is more likely than not to be sustained upon audit based on the technical merits of the tax position. Settlements with tax authorities, the expiration of statutes of limitations for particular tax positions, or obtaining new information on particular tax positions may cause a change to the effective tax rate. The Company recognizes accrued interest related to unrecognized tax benefits as interest expense and penalties as operating expense in the consolidated statements of operations.

(m) Computation of Net Income (Loss) per Share

Basic earnings per share is computed by dividing income available to common stockholders (the numerator) by the weighted‑average number of common shares outstanding (the denominator) for the period. The computation of diluted earnings per share is similar to basic earnings per share, except that the denominator is increased to include the number of additional common shares that would have been outstanding if the potentially dilutive common shares had been issued, calculated using the treasury stock method.

The Company incurred a net loss for the year ended December 31, 2014, and has excluded 1,165,855 of incremental shares attributable to outstanding stock options and restricted stock units from the calculation of net loss per share because the effect would have been anti‑dilutive.

The components of net income (loss) per share are as follows:


	Year ended December 31,
	2016		2015		2014
	(in thousands, except per share data)
Net income (loss) available to common stockholders	$	11,001	$	14,678	$	(11,266)
Weighted average common shares outstanding used in computing basic income (loss) per share		29,195		28,595		27,862
Incremental options and RSUs		1,752		1,634		—
Weighted average common shares outstanding used in computing diluted net income (loss) per share		30,947		30,229		27,862
Net income (loss) per share
Basic	$	0.38	$	0.51	$	(0.40)
Diluted	$	0.36	$	0.49	$	(0.40)

(n) Accumulated Other Comprehensive Income

The following table presents the changes in accumulated other comprehensive income, net of tax, by component for the year ended December 31, 2016:


	Foreign		Defined benefit
	currency		pension plan		Total
	(in thousands)
Balance at December 31, 2015	$	(744)	$	(687)	$	(1,431)
Other comprehensive loss and pension reclassification		(847)		(1)		(848)
Balance at December 31, 2016	$	(1,591)	$	(688)	$	(2,279)

(o) Recent Accounting Guidance

Accounting Standards or Updates Recently Adopted

In November 2015, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2015-17, “Income Taxes (Topic 740): Balance Sheet Classification of Deferred Taxes.” The amendments in this ASU require entities that present classified statements of financial position to classify deferred tax liabilities and assets as noncurrent. They apply to all entities that present a classified statement of financial position. For public business entities, the amendments in this ASU are effective for financial statements issued for annual periods beginning after December 15, 2016, and interim periods within those annual periods. The Company adopted ASU No. 2015-17 early, effective June 30, 2016, on a prospective basis. As a result, the Company presented all deferred tax assets and liabilities as noncurrent on the consolidated balance sheet as of December 31, 2016, reducing current deferred tax assets by $0.2 million, long-term deferred tax assets by $0.3 million and short-term deferred tax liabilities by $0.5 million. The current deferred tax assets and liabilities on the consolidated balance sheet as of December 31, 2015, have not been reclassified.

In August 2014, the FASB issued ASU No. 2014-15, “Disclosure of Uncertainties about an Entity’s Ability to Continue as a Going Concern.” ASU 2014-15 introduces an explicit requirement for management to assess if there is substantial doubt about an entity’s ability to continue as a going concern, and to provide related footnote disclosures in certain circumstances. In connection with each annual and interim period, management must assess if there is substantial doubt about an entity’s ability to continue as a going concern within one year after the issuance date. Disclosures are required if conditions give rise to substantial doubt. The adoption of this standard did not have a material impact on the Company’s consolidated financial statements.

Accounting Standards or Updates Not Yet Effective

In May 2014, the FASB issued ASU No. 2014-09, “Revenue from Contracts with Customers,” which provides guidance for revenue recognition. The standard’s core principle is that a company will recognize revenue when it transfers promised goods or services to customers in an amount that reflects the consideration to which the company expects to be entitled in exchange for those goods or services. In April 2016, the FASB issued ASU 2016-10, “Revenue from Contracts with Customers” (Topic 606): Identifying Performance Obligations and Licensing, which further clarifies performance obligations in a contract with a customer. In May 2016, the FASB issued ASU 2016-12, “Revenue from Contracts with Customers” (Topic 606): Narrow-Scope Improvements and Practical Expedients, which provides a more narrow interpretation of ASU No. 2014-09. These ASUs are effective for annual reporting periods beginning after December 15, 2017 and interim periods within those annual periods. The Company is currently assessing the potential impact the adoption of these standards will have on the financial statements.

In July 2015, the FASB issued ASU No. 2015-11, “Simplifying the Measurement of Inventory,” which changes the inventory measurement principles for entities using the first-in, first-out (FIFO) or average cost methods. For entities utilizing one of these methods, the inventory measurement principle will change from lower of cost or market to the lower of cost and net realizable value. Net realizable value is the estimated selling price in the ordinary course of business, less the reasonably predictable costs of completion, disposal and transportation. The amendments are effective for annual and interim periods beginning after December 15, 2016. The adoption of this ASU will not have a material impact on the Company’s financial statements and disclosures.

In February 2016, the FASB issued ASU No. 2016-02 “Leases.” The ASU requires lessees to recognize the rights and obligations created by most leases as assets and liabilities on their balance sheet and continue to recognize expenses on their income statement over the lease term. It will also require disclosures designed to give financial statement users information on the amount, timing, and uncertainty of cash flows arising from leases. The guidance is effective for annual reporting periods beginning after December 15, 2018, and interim periods within those years. Early adoption is permitted for all entities. The Company is currently evaluating the impact of ASU 2016-02 on the consolidated financial statements and disclosures.

In March 2016, the FASB issued ASU No. 2016-09 “Compensation — Stock Compensation,” which changes the accounting for stock-based payment transactions, including the income tax consequences, classification of awards as either equity or liabilities, and classification on the statement of cash flows. For public business entities, the amendments in this ASU are effective for annual periods beginning after December 15, 2016, and interim periods within those annual periods. Early adoption is permitted for all entities and any entity that elects early adoption must adopt all of the amendments in the same period. The adoption of this ASU will not have a material impact on the Company’s financial statements and disclosures.

In November 2016, the FASB issued ASU 2016-18, “Statement of Cash Flows (Topic 230): Restricted Cash (a consensus of the FASB Emerging Issues Task Force).” This ASU requires the statement of cash flows to explain the change during the period in the total of cash, cash equivalents, and amounts generally described as restricted cash or restricted cash equivalents. Therefore, amounts generally described as restricted cash and restricted cash equivalents are to be included with cash and cash equivalents when reconciling the beginning of period and end of period amounts shown on the statement of cash flows. ASU No. 2016-18 will be effective for annual reporting periods beginning after December 15, 2017. The adoption of this ASU will not have a material impact on the Company’s financial statements and disclosures.

Correction of Accounting Error in Prior Period

12 Months Ended

Dec. 31, 2016

Correction of Accounting Error in Prior Period

Correction of Accounting Error in Prior Period

Note 3. Correction of Accounting Error in Prior Period

Subsequent to March 31, 2016, but prior to filing the Form 10-Q for the quarter ended June 30, 2016, the Company discovered a cumulative error associated with the elimination of profits on sales of inventory to its subsidiaries. This error had no impact upon the Company’s consolidated statement of operations or consolidated statement of cash flows subsequent to the year ended December 31, 2010. The following financial statement line items reported in the Company’s consolidated balance sheet for the year ended December 31, 2015 was affected by the correction of this accounting error:


(in thousands)	Previously Reported December 31, 2015			Adjusted December 31, 2015	Effect of Change
Inventory, net	$	115,904	$	109,408	$	(6,496)
Total current assets		236,453		229,957		(6,496)
Total assets		288,280		281,784		(6,496)
Accumulated deficit		(336,209)		(342,705)		(6,496)
Total stockholders' equity		190,260		183,764		(6,496)
Total liabilities and stockholders' equity	$	288,280	$	281,784	$	(6,496)

This error was associated with transactions occurring prior to September 2010, at which time the Company revised its methodology to compute and eliminate intercompany profits. However, the Company failed to identify and record an entry to eliminate the cumulative error resulting from the prior methodology. This $6.5 million error resulted in an overstatement of inventory and a cumulative understatement of cost of product revenue as of September 2010. Thereafter, the effect was an overstatement of inventory and understatement of accumulative deficit for each subsequent reporting period. The consolidated balance sheets as of December 31, 2015 and 2014 have been revised to reflect the correction of the error through a decrease in inventory and an increase in accumulated deficit of $6.5 million. In the opinion of management, the effect is not material to the consolidated financial position or results of operations for any previously reported period.

1-for-4 Reverse Stock Split	12 Months Ended
1-for-4 Reverse Stock Split	Dec. 31, 2016
1-for-4 Reverse Stock Split
1-for-4 Reverse Stock Split	Note 4. 1-for-4 Reverse Stock Split As of 6:00 PM Eastern Time on June 30, 2016, the Company effected a 1-for-4 reverse stock split of its common stock. The Company continues to be traded under its unchanged symbol “ACLS.” All previously reported common stock share amounts in the accompanying financial statements and related notes have been retroactively adjusted to reflect the reverse stock split. As a result of the reduced number of shares outstanding after the reverse stock split, the stated capital attributable to common stock on the Company’s balance sheet (which consists of the unchanged $0.001 par value per share multiplied by the aggregate number of shares issued and outstanding), has been reduced. Correspondingly, the Company’s additional paid-in capital account, which consists of the difference between its stated capital and the aggregate amount paid to the Company upon issuance of all currently outstanding shares of its common stock, has been credited with the amount by which the stated capital was reduced. The Company’s stockholders’ equity, in the aggregate, remains unchanged. Immediately prior to the effectiveness of the reverse stock split, the Company retired 30 thousand shares of common stock held in treasury to the status of authorized and unissued.

Restricted Cash	12 Months Ended
Restricted Cash	Dec. 31, 2016
Restricted Cash
Restricted Cash	Note 5. Restricted Cash The restricted cash of $6.9 million at December 31, 2016 relates to a $5.9 million letter of credit associated to the security deposit for the sale leaseback transaction, a $0.9 million letter of credit relating to workers’ compensation insurance and a $0.1 million deposit relating to customs activity. The change in restricted cash is classified in the statement of cash flows as a financing activity.

Accounts Receivable, net

12 Months Ended

Dec. 31, 2016

Accounts Receivable, net

Accounts Receivable, net

Note 6. Accounts Receivable, net

The components of accounts receivable are as follows:


	December 31,
	2016		2015
	(in thousands)
Trade receivables	$	50,650	$	36,868
Allowance for doubtful accounts		(77)		—
Trade receivables, net	$	50,573	$	36,868

Inventories, net

12 Months Ended

Dec. 31, 2016

Inventories, net

Inventories, net

Note 7. Inventories, net

The components of inventories are as follows:


	December 31,
	2016		2015
	(in thousands)
Raw materials	$	80,503	$	72,070
Work in process		14,117		29,219
Finished goods (completed systems)		19,233		8,119
Inventories, net	$	113,853	$	109,408

When recorded, inventory reserves are intended to reduce the carrying value of inventories to their market value. The Company establishes inventory reserves when conditions exist that indicate inventory may be in excess of anticipated demand or is obsolete based upon assumptions about future demand for the Company’s products or market conditions. The Company regularly evaluates the ability to realize the value of inventories based on a combination of factors including the following: forecasted sales or usage, estimated product end of life dates, estimated current and future market value and new product introductions. Purchasing and usage alternatives are also explored to mitigate inventory exposure. In 2016, the Company recorded an overall decrease of $1.6 million in the inventory reserves, which consisted of disposals due to previously reserved for obsolescence and excess inventory of $2.6 million partially offset by a provision charge to the reserve of $1.0 million. As of December 31, 2016 and 2015, inventories are stated net of inventory reserves of $8.8 million and $10.5 million respectively.

During each of the years ended 2016, 2015 and 2014, the Company recorded charges to cost of sales of $0.8 million, $0.5 million and $0.8 million to reflect the lower of cost or market value. During 2014, the Company recorded a charge to cost of sales of $1.0 million due to production levels below normal capacity.

Property, Plant and Equipment, net

12 Months Ended

Dec. 31, 2016

Property, Plant and Equipment, net.

Property, Plant and Equipment, net

Note 8. Property, Plant and Equipment, net

The components of property, plant and equipment are as follows:


	December 31,
	2016		2015
	(in thousands)
Land and buildings	$	75,792	$	80,491
Machinery and equipment		9,472		11,080
Construction in process		1,704		1,451
Total cost		86,968		93,022
Accumulated depreciation		(56,128)		(62,991)
Property, plant and equipment, net	$	30,840	$	30,031

Depreciation expense was $1.8 million, $2.4 million and $2.4 million for the years ended December 31, 2016, 2015 and 2014, respectively.

Assets Manufactured for Internal Use, net

12 Months Ended

Dec. 31, 2016

Assets Manufactured for Internal Use, net

Assets Manufactured for Internal Use, net

Note 9. Assets Manufactured for Internal Use, net

The components of assets manufactured for internal use, included in amounts reported as other assets, are as follows:


	December 31,
	2016		2015
	(in thousands)
Internal use assets	$	42,776	$	31,759
Construction in process		1,745		470
Total cost		44,521		32,229
Accumulated depreciation		(22,838)		(20,193)
Assets manufactured for internal use, net	$	21,683	$	12,036

These products are used for research and development, training, and customer demonstration purposes.

Depreciation expense was $2.4 million, $2.5 million and $2.2 million for the years ended December 31, 2016, 2015 and 2014, respectively.

Restructuring Charges

12 Months Ended

Dec. 31, 2016

Restructuring Charges.

Restructuring Charges

Note 10. Restructuring Charges

In the first quarter of 2016, due to changes in customer service contracts resulting from a consolidation in our customer base, the Company had severance and other costs related to a reduction in force.

The Company’s restructuring liability for the years ended December 31, 2016, 2015 and 2014 are as follows:


	Severance
	(in thousands)
Balance at December 31, 2014	$	481
Severance, related costs and other adjustments		(2)
Cash payments		(479)
Balance at December 31, 2015	$	—
Severance and related costs		282
Cash payments		(282)
Balance at December 31, 2016	$	—

Product Warranty

12 Months Ended

Dec. 31, 2016

Product Warranty

Product Warranty

Note 11. Product Warranty

The Company generally offers a one year warranty for all of its systems, the terms and conditions of which vary depending upon the product sold. For all systems sold, the Company accrues a liability for the estimated cost of standard warranty at the time of system shipment and defers the portion of systems revenue attributable to the fair value of non‑standard warranty. Costs for non‑standard warranty are expensed as incurred. Factors that affect the Company’s warranty liability include the number of installed units, historical and anticipated product failure rates, material usage and service labor costs. The Company periodically assesses the adequacy of its recorded liability and adjusts the amount as necessary.

The changes in the Company’s product warranty liability are as follows:



	Year ended December 31,
	2016		2015		2014
	(in thousands)
Balance at January 1 (beginning of year)	$	3,555	$	1,526	$	1,428
Warranties issued during the period		3,125		4,305		1,743
Settlements made during the period		(4,249)		(2,672)		(2,096)
Changes in estimate of liability for pre-existing warranties during the period		235		396		451
Balance at December 31 (end of period)	$	2,666	$	3,555	$	1,526

Amount classified as current	$	2,426	$	3,363	$	1,352
Amount classified as long-term		240		192		174
Total warranty liability	$	2,666	$	3,555	$	1,526

Financing Arrangements	12 Months Ended
Financing Arrangements	Dec. 31, 2016
Financing Arrangements
Financing Arrangements	Note 12. Financing Arrangements Sale Leaseback Obligation On January 30, 2015, the Company sold its corporate headquarters facility for the purchase price of $48.9 million. As part of the sale, the Company also entered into a 22-year lease agreement with the buyer. The sale leaseback is accounted for as a financing arrangement for financial reporting and, as such, the Company recorded a financing obligation of $47.6 million as of December 31, 2016. The associated lease payments include both an interest component and payment of principal, with the underlying liability being extinguished at the end of the original lease term. The Company posted a collateralized security deposit of $5.9 million in the form of an irrevocable letter of credit at the time of the closing. Upon the termination of our credit facility with Silicon Valley Bank in October 2015, this letter of credit was cash collateralized.

Employee Benefit Plans

12 Months Ended

Dec. 31, 2016

Employee Benefit Plans

Employee Benefit Plans

Note 13. Employee Benefit Plans

(a) Defined Contribution Plan

The Company maintains the Axcelis Long-Term Investment Plan, a defined contribution plan. All regular employees are eligible to participate and may contribute up to 35% of their compensation on a before-tax basis subject to Internal Revenue Service (“IRS”) limitations. Highly compensated employees may contribute up to 16% of their compensation on a before-tax basis subject to IRS limitations. In 2015, the Company implemented a matching contribution of up to one thousand U.S. dollars on a dollar-for-dollar basis on contributions by eligible participants. In 2016, the Company increased the matching contribution to a maximum of one thousand two hundred U.S. dollars, on the basis of one dollar matched for each two dollars contributed by eligible participants. Total related expense for 2016 and 2015 was $0.4 million.

(b) Other Compensation Plans

The Company operates in foreign jurisdictions that require lump sum benefits, payable based on statutory regulations, for voluntary or involuntary termination. Where required, an annual actuarial valuation of the benefit plans is obtained.

The Company has recorded an unfunded liability of $4.0 million and $3.9 million at December 31, 2016 and 2015, respectively, for costs associated with these compensation plans in foreign jurisdictions. The following table presents the classification of these liabilities in the Consolidated Balance Sheets:


	Year ended
	December 31,
	2016		2015
	(in thousands)
Current:
Accrued compensation	$	902	$	857
Total current liabilities	$	902	$	857
Long-term:
Other long-term liabilities		3,057		3,052
Total liabilities	$	3,959	$	3,909

The expense recorded in connection with these plans was $0.8 million, $0.7 million and $0.7 million during the years ended December 31, 2016, 2015 and 2014, respectively.

Stock Award Plans and Stock Based Compensation

12 Months Ended

Dec. 31, 2016

Stock-Based Compensation

Stock Award Plans and Stock Based Compensation

Note 14. Stock Award Plans and Stock Based Compensation

(a) Equity Incentive Plans

The Company maintains the Axcelis Technologies, Inc. 2012 Equity Incentive Plan (the “2012 Equity Plan”), which became effective on May 2, 2012. Our 2000 Stock Plan (the “2000 Stock Plan”) expired on May 1, 2012 and no new grants may be made under that plan after that date. However, awards granted under the 2000 Stock Plan prior to the expiration remain outstanding and subject to the terms of the 2000 Stock Plan.

The 2012 Equity Plan, as amended, reserves 5.5 million shares of common stock, $0.001 par value, for grant and permits the issuance of options, stock appreciation rights, restricted stock, restricted stock units, stock equivalents and awards of shares of common stock that are not subject to restrictions or forfeiture to selected employees, directors and consultants of the Company. Shares that are not issued under an award (because such award expires, is terminated unexercised or is forfeited) that were outstanding under the 2000 Stock Plan as of the May 2, 2012, increase the reserve of shares available for grant under the 2012 Equity Plan.

The term of stock options granted under these plans is specified in the award agreements. Unless a lesser term is otherwise specified by the Compensation Committee of the Company’s Board of Directors, awards under the 2012 Equity Plan will expire seven years from the date of grant. In general, all awards issued under the 2000 Stock Plan expire ten years from the date of grant. Under the terms of these stock plans, the exercise price of a stock option may not be less than the fair market value of a share of the Company’s common stock on the date of grant. Under the 2012 Equity Plan, fair market value is defined as the last reported sale price of a share of the common stock on a national securities exchange as of any applicable date, as long as the Company’s shares are traded on such exchange.

Stock options granted to employees generally vest over a period of four years, while stock options granted to non‑employee members of the Company’s Board of Directors generally vest over a period of six months and, once vested, are not affected by the director’s termination of service to the Company. In limited circumstances, the Company may grant stock option awards with market-based vesting conditions, such as the Company’s common stock price, or other performance conditions. Termination of service by an employee will cause options to cease vesting as of the date of termination, and in most cases, employees will have 90 days after termination to exercise options that were vested as of the termination of employment. In general, retiring employees will have one year after termination of employment to exercise vested options. The Company settles stock option exercises with newly issued common shares.

Restricted stock units granted to employees during 2016 had both time-based vesting provisions and performance-based vesting provisions. Generally, unvested restricted stock unit awards expire upon termination of service to the Company. The Company settles restricted stock units upon vesting with newly issued common shares. No restricted stock was granted under either stock plan during the three year period ended December 31, 2016.

As of December 31, 2016, there were 0.7 million shares available for grant under the 2012 Equity Plan. No shares are available for grant under the 2000 Stock Plan.

As of December 31, 2016, there were 5.0 million options outstanding under the 2012 Equity Plan and the 2000 Stock Plan, collectively, and 0.5 million unvested restricted stock units outstanding under the 2012 Stock Plan.

(b) Employee Stock Purchase Plan

The Employee Stock Purchase Plan (the “Purchase Plan”) provides effectively all of the Company’s employees the opportunity to purchase common stock of the Company at less than market prices. Purchases are made through payroll deductions of up to 10% of the employee’s salary as elected by the participant, subject to certain caps set forth in the Purchase Plan. Employees may purchase the Company’s common stock at 85% of its market on the day the stock is purchased.

The Purchase Plan is considered compensatory and as such, compensation expense has been recognized based on the benefit of the discounted stock price, amortized to compensation expense over each offering period of six months. Compensation expense relating to the Purchase Plan was approximately $0.1 million for each of the years ended December 31, 2016, 2015 and 2014.

As of December 31, 2016, there were a total of 0.3 million shares reserved for issuance and available for purchase under the Purchase Plan. Less than 0.1 million shares were purchased under the Purchase Plan in each of the years ended December 31, 2016, 2015 and 2014.

For the purpose of valuing stock options with service conditions, the Company uses the Black‑Scholes option pricing model to calculate the grant‑date fair value of an award. The fair values of options granted were calculated using the following estimated weighted‑average assumptions:


	Year ended December 31,
	2016	2015	2014
Weighted-average expected volatility	49.3% — 56.7%	56.2% — 64.7%	60.6% — 98.4%
Weighted-average expected term	4.7 years	4.6 — 4.7 years	3.8 — 4.7 years
Risk-free interest rate	1.1% — 2.0%	1.3% — 1.6%	1.2% — 1.7%
Expected dividend yield	0%	0%	0%

Expected volatility—The Company considers a number of factors when estimating volatility for stock options granted. The Company’s method of estimating expected volatility relies on a combination of historical and implied volatility. The Company believes that this blended volatility results in an accurate estimate of the grant‑date fair value of employee stock options because it appropriately reflects the market’s current expectations of future volatility.

Expected term—The Company calculated the weighted average expected term for stock options granted prior to July 1, 2012, using a forward looking lattice model of the Company’s stock price incorporating a suboptimal exercise factor and a projected post‑vest forfeiture rate. For stock options granted after July 1, 2012 to employees and to non‑employee members of the Company’s Board of Directors, the Company used the simplified method for estimating the expected life of “plain vanilla” options because it did not have sufficient exercise history to use a lattice model. The Company expects that it will use a lattice model once sufficient exercise history has been established. A change in the contractual life from 10 years to 7 years was made to reflect the fact that options granted after May 1, 2012 were granted under the 2012 Equity Incentive Plan, which limits option terms to seven years.

Risk‑free interest rate - The yield on zero‑coupon U.S. Treasury securities for a period that is commensurate with the expected term assumption is used as the risk‑free interest rate.

Expected dividend yield—Expected dividend yield was not considered in the option pricing formula since the Company does not pay dividends and has no current plans to do so in the future.

In limited circumstances, the Company also issues stock option grants with vesting based on market conditions, such as the Company’s common stock price, or a combination of time or market or performance conditions. The fair values and derived service periods for all grants that have vesting based on market or performance conditions are estimated using the Monte Carlo valuation method. For each stock option grant with vesting based on a combination of time and performance or market conditions, where vesting will occur if either condition is met, the related compensation costs are recognized over the shorter of the explicit service period or the derived service period.

The fair value of the Company’s restricted stock units is calculated based upon the fair market value of the Company’s stock at the date of grant.

(d) Summary of Stock-based Compensation Expense

The Company uses the straight‑line attribution method to recognize expense for stock‑based awards such that the expense associated with awards is evenly recognized throughout the period.

The amount of stock‑based compensation recognized is based on the value of the portion of the awards that are ultimately expected to vest. The Company estimates forfeitures at the time of grant and revises them, if necessary, in subsequent periods if actual forfeitures differ from those estimates. The term “forfeitures” is distinct from “cancellations” or “expirations” and represents only the unvested portion of the surrendered stock‑based award. Based on a historical analysis, a forfeiture rate of 5% per year was applied to stock‑based awards, including executive officer awards, for the years ended December 31, 2016, 2015 and 2014.

For the year ended December 31, 2016, the Company recognized stock-based compensation expense of $5.2 million. Stock-based compensation expense was $5.6 million and $4.8 million for the years ended December 31, 2015 and 2014, respectively. The Company presents the expenses related to stock-based compensation in the same expense line items as cash compensation paid to its employees. For the year ended December 31, 2016, the Company primarily used restricted stock units in its annual equity compensation program. For the years ended December 31, 2015 and 2014, the Company primarily used stock options in its annual equity compensation program.

The benefit of tax deductions in excess of recognized compensation cost is reported as a financing cash flow, rather than as an operating cash flow. Because the Company does not recognize the benefit of tax deductions in excess of recognized compensation cost due to its cumulative net operating loss position, this had no impact on the Company’s consolidated statement of cash flows as of and for the years ended December 31, 2016, 2015 or 2014.

(e) Stock Option Awards

The following table summarizes the stock option activity for the year ended December 31, 2016:


				Weighted
		Weighted		Average
		Average		Remaining	Aggregate
		Exercise		Contractual	Intrinsic
	Options	Price		Term	Value
	(in thousands)			(years)	(in thousands)
Outstanding at December 31, 2015	5,417	$	7.29
Granted	42		13.34
Exercised	(392)		5.71
Canceled	(56)		8.98
Expired	(60)		20.66
Outstanding at December 31, 2016	4,951	$	7.29	3.94	$	36,018
Exercisable at December 31, 2016	3,756	$	6.49	3.63	$	30,321
Options Vested or Expected to Vest at December 31, 2016(1)	4,886	$	7.25	3.97	$	35,743

(1)

In addition to the vested options, the Company expects a portion of the unvested options to vest at some point in the future. Options expected to vest is calculated by applying an estimated forfeiture rate to the unvested options.

The total intrinsic value, which is defined as the difference between the market price at exercise and the price paid by the employee to exercise the options, for options exercised during the years ended December 31, 2016, 2015 and 2014 was $2.5 million, $5.3 million and $2.4 million, respectively.

The total fair value of stock options vested during the years ended December 31, 2016, 2015 and 2014 was $3.9 million, $5.4 million and $4.7 million respectively. The weighted average grant-date fair value of options granted for the years ended December 31, 2016, 2015 and 2014 was $5.75, $5.05 and $3.82, respectively. As of December 31, 2016, there was $4.8 million of total forfeiture‑adjusted unrecognized compensation cost related to non‑vested stock options granted under the 2012 Equity Incentive Plan and the 2000 Stock Plan. That cost is expected to be recognized over a weighted‑average period of 2.1 years.

(f) Restricted Stock and Restricted Stock Units

Restricted stock units (“RSUs”) represent the Company’s unfunded and unsecured promise to issue shares of the common stock at a future date, subject to the terms of the RSU Award Agreement in either the 2012 Equity Incentive Plan or the 2000 Stock Plan. The purpose of these awards is to assist in attracting and retaining highly competent employees and directors and to act as an incentive in motivating selected employees and directors to achieve long-term corporate objectives. RSU awards granted in 2016 included time vested share awards and awards with performance vesting conditions. No restricted stock awards were granted, or vested, during the years ended December 31, 2016, 2015 and 2014. The fair value of a restricted stock unit and restricted stock award is charged to expense ratably over the applicable service period.

Changes in the Company’s non‑vested restricted stock units for the year ended December 31, 2016 is as follows:


		Weighted-Average
		Grant Date Fair
	Shares/units	Value per Share
	(in thousands)
Outstanding at December 31, 2015	91	$	11.39
Granted	571		9.73
Vested	(110)		10.50
Forfeited	(4)		9.64
Outstanding at December 31, 2016	548	$	9.85

The weighted average grant-date fair value of restricted stock units granted for the years ended December 31, 2016, 2015 and 2014 was $9.73, $12.12 and $8.68, respectively. Some restricted stock units provide for net share settlement to offset the personal income tax obligations of the employee’s restricted stock unit vesting. Vesting activity above reflects shares vested before net share settlement.

Stockholders' Equity	12 Months Ended
Stockholders' Equity	Dec. 31, 2016
Stockholders' Equity
Stockholders' Equity	Note 15. Stockholders’ Equity Preferred Stock The Company may issue up to 30 million shares of preferred stock in one or more series. The Board of Directors is authorized to fix the rights and terms for any series of preferred stock without additional shareholder approval. As of December 31, 2016 and 2015, there were no outstanding shares of preferred stock.

- Definition

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

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(d),(e))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21484-112644

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SAB TOPIC 4.E)
-URI http://asc.fasb.org/extlink&oid=27010918&loc=d3e74512-122707

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21488-112644

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.29-31)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 4
-Subparagraph (SAB TOPIC 4.C)
-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187143-122770

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21506-112644

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770

Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 30
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6405834&loc=d3e23285-112656

Reference 10: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21475-112644

Reference 11: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Preferred Stock
-URI http://asc.fasb.org/extlink&oid=6521494

Reference 12: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 2
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Reference 14: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Staff Accounting Bulletin (SAB)
-Number Topic 4
-Section E

Reference 15: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Staff Accounting Bulletin (SAB)
-Number Topic 4
-Section C

+ Details

Fair Value Measurements

12 Months Ended

Dec. 31, 2016

Fair Value Measurements

Fair Value Measurements

Note 16. Fair Value Measurements

Fair value is defined as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date.

(a) Fair Value Hierarchy

The accounting guidance for fair value measurement requires an entity to maximize the use of observable inputs and minimize the use of unobservable inputs when measuring fair value. The standard establishes a fair value hierarchy based on the level of independent, objective evidence surrounding the inputs used to measure fair value. A financial instrument’s categorization within the fair value hierarchy is based upon the lowest level of input that is significant to the fair value measurement. The fair value hierarchy is as follows:

Level 1—applies to assets or liabilities for which there are quoted prices in active markets for identical assets or liabilities.

Level 2—applies to assets or liabilities for which there are inputs other than quoted prices that are observable for the asset or liability, such as quoted prices for similar assets or liabilities in active markets; quoted prices for identical assets or liabilities in markets with insufficient volume or infrequent transactions (less active markets); or model‑derived valuations in which significant inputs are observable or can be derived principally from, or corroborated by, observable market data.

Level 3—applies to assets or liabilities for which there are unobservable inputs to the valuation methodology that are significant to the measurement of the fair value of the assets or liabilities.

(b) Assets and Liabilities Measured at Fair Value

The Company’s money market funds are included in cash and cash equivalents in the consolidated balance sheets, and are considered a level 1 investment as they are valued at quoted market prices in active markets. The Company’s sale leaseback obligation relating to the sale of our corporate headquarters is carried at amortized cost, which approximates fair value based on an implied borrowing rate of 10.65%. The underlying cash flow associated with our lease payments is being applied to both an interest and principal component using the effective interest method over the associated lease term. The liability is categorized as level 3 within the fair value hierarchy.

The following table sets forth Company’s assets and liabilities which are measured at fair value by level within the fair value hierarchy.


	December 31, 2016
	Fair Value Measurements
	Level 1		Level 2		Level 3		Total
	(in thousands)
Assets
Cash equivalents:
Money market funds	$	54,170	$	—	$	—	$	54,170


	December 31, 2015
	Fair Value Measurements
	Level 1		Level 2		Level 3		Total
	(in thousands)
Assets
Cash equivalents:
Money market funds	$	65,327	$	—	$	—	$	65,327
Liabilities
Sale leaseback obligation	$	—	$	—	$	47,586	$	47,586

The carrying amounts reflected in the consolidated balance sheets for cash and cash equivalents (which are comprised primarily of money market funds and deposit accounts), accounts receivable, prepaid expenses and other current and non‑current assets, restricted cash, accounts payable and accrued expenses approximate fair value due to their short‑term maturities.

- Definition

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

+ References + Details

Commitments and Contingencies

12 Months Ended

Dec. 31, 2016

Contingencies

Commitments and Contingencies

Note 17. Commitments and Contingencies

(a) Lease Commitments

The Company leases manufacturing and office facilities and certain equipment under operating leases that expire through 2037. Rental expense was $3.8 million, $3.8 million and $3.7 million under operating leases for the years ended December 31, 2016, 2015 and 2014, respectively. Future minimum lease commitments on non‑cancelable operating leases for the year ended December 31, 2016 are as follows:


	Operating
	Leases
	(in thousands)
2017	$	2,581
2018		1,390
2019		704
2020		352
2021		201
Thereafter		—
	$	5,228

(b) Sale Leaseback Financing Obligation

In addition to the lease commitments as described above, the Company entered into a 22-year lease agreement relating to our corporate headquarters in Beverly, Massachusetts. The following table relates to the cash payment schedule associated with this lease obligation as of December 31, 2016:


	Lease
	Obligation
	(in thousands)
2017	$	5,315
2018		5,470
2019		5,594
2020		5,719
2021		5,848
Thereafter		97,999
Total lease payments	$	125,945
Less interest portion		(78,359)
Sale leaseback obligation	$	47,586

The Company has non‑cancelable contracts and purchase orders for inventory of $43.9 million at December 31, 2016.

(d) Litigation

The Company is not presently a party to any litigation that it believes might have a material adverse effect on its business operations. The Company is, from time to time, a party to litigation that arises in the normal course of its business operations.

(e) Indemnifications

The Company’s system sales agreements typically include provisions under which the Company agrees to take certain actions, provide certain remedies and defend its customers against third‑party claims of intellectual property infringement under specified conditions and to indemnify customers against any damage and costs awarded in connection with such claims. The Company has not incurred any material costs as a result of such indemnifications and has not accrued any liabilities related to such obligations in the accompanying consolidated financial statements.

Business Segment and Geographic Region Information

12 Months Ended

Dec. 31, 2016

Business Segment and Geographic Region Information

Business Segment and Geographic Region Information

Note 18. Business Segment and Geographic Region Information

The Company operates in one business segment, which is the manufacture of capital equipment for the semiconductor chip manufacturing industry. The principal market for semiconductor capital equipment is semiconductor chip manufacturers. Substantially all sales are made directly by the Company to its customers located in the United States, Europe and Asia Pacific.

The Company’s ion implantation systems product line includes high current, medium current and high energy implanters. Other products include legacy dry strip equipment, curing systems, and thermal processing systems. In addition to new equipment, the Company provides post‑sales equipment service and support, including spare parts, equipment upgrades, used equipment, maintenance services and customer training.

Revenue by product lines is as follows:


	Year ended December 31,
	2016		2015		2014
	(in thousands)
Ion implantation systems and services	$	248,885	$	282,624	$	183,148
Other systems and services		18,095		18,871		19,903
Total revenue	$	266,980	$	301,495	$	203,051

Revenue and long‑lived assets by geographic region, based on the physical location of the operation recording the sale or the asset, are as follows:


			Long-Lived
	Revenue		Assets
	(in thousands)
2016
United States	$	191,261	$	52,006
Europe		25,436		—
Asia Pacific		50,283		517
	$	266,980	$	52,523
2015
United States	$	226,890	$	41,729
Europe		24,209		—
Asia Pacific		50,396		334
	$	301,495	$	42,063
2014
United States	$	126,255	$	40,001
Europe		29,140		—
Asia Pacific		47,656		299
	$	203,051	$	40,300

Long‑lived assets consist of property, plant and equipment, net, and assets manufactured for internal use. Operations in Europe and Asia Pacific consist of sales and service organizations.

International revenue, which includes export sales from U.S. manufacturing facilities to foreign customers and sales by foreign subsidiaries and branches, was $213.8 million (80.0% of total revenue), $256.5 million (85.1% of total revenue) and $162.4 million (80.0% of total revenue) in 2016, 2015 and 2014, respectively.

- Definition

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

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 34
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Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
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Reference 3: http://www.xbrl.org/2003/role/presentationRef
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Reference 4: http://www.xbrl.org/2003/role/presentationRef
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Reference 5: http://www.xbrl.org/2003/role/presentationRef
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Reference 6: http://www.xbrl.org/2003/role/presentationRef
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Reference 7: http://www.xbrl.org/2003/role/presentationRef
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Reference 8: http://www.xbrl.org/2003/role/presentationRef
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Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
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-Paragraph 40
-URI http://asc.fasb.org/extlink&oid=51669610&loc=d3e9031-108599

Reference 10: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 10
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-Name Accounting Standards Codification
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Reference 12: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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Reference 13: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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Reference 14: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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-URI http://asc.fasb.org/extlink&oid=51669610&loc=d3e8906-108599

+ Details

Income Taxes

12 Months Ended

Dec. 31, 2016

Income Taxes

Income Taxes

Note 19. Income Taxes

Income (loss) before income taxes is as follows:


	Year ended December 31,
	2016		2015		2014
	(in thousands)
United States	$	8,880	$	12,708	$	(11,987)
Foreign		2,144		2,497		1,820
Income (loss) before income taxes	$	11,024	$	15,205	$	(10,167)

Provision for income taxes is as follows:


	Year ended December 31,
	2016		2015		2014
	(in thousands)
Current:
United States
Federal	$	—	$	—	$	—
State		49		(33)		59
Foreign		(217)		374		780
Total current		(168)		341		839
Deferred:
Foreign		191		186		260
Total deferred		191		186		260
Income tax provision	$	23	$	527	$	1,099

Reconciliations of income taxes at the United States Federal statutory rate to the effective income tax rate are as follows:


	Year ended December 31,
	2016		2015		2014
	(in thousands)
Income tax benefit at the United States statutory rate	$	3,859	$	5,322	$	(3,558)
State income taxes		32		(22)		38
Unrecognized tax benefits		(615)		(174)		184
Effect of change in valuation allowance		(7,765)		(5,676)		(6,835)
Foreign income tax rate differentials		233		600		259
Unremitted earnings of foreign subsidiaries		305		(102)		(758)
Stock options		264		379		686
Credit expirations		3,565		—		—
Deemed distribution from foreign subsidiaries		—		—		607
Discrete items, net		—		(540)		9,143
Other, net		145		740		1,333
Income tax provision	$	23	$	527	$	1,099

Significant components of current and long‑term deferred income taxes are as follows:


	`	As of December 31,
		2016				2015
		Current		Long Term		Current		Long Term
		(in thousands)
Federal net operating loss carryforwards		$	—	$	98,007	$	—	$	101,479
State net operating loss carryforwards			—		1,546		—		1,636
Foreign net operating loss carryforwards			—		673		—		810
Federal tax credit carryforwards			—		12,778		—		16,343
State tax credit carryforwards			—		2,566		—		3,964
Unremitted earnings of foreign subsidiaries			—		(8,913)		—		(8,632)
Intangible assets			—		229		—		286
Property, plant and equipment			—		9,774		—		9,331
Accrued compensation			—		97		1,082		—
Inventories			—		5,230		2,541		—
Stock compensation			—		6,687		—		6,001
Warranty			—		930		1,214		—
Other			—		(5,578)		1,237		(3,945)
Deferred taxes, gross			—		124,026		6,074		127,273
Valuation allowance			—		(122,966)		(6,335)		(125,928)
Deferred taxes, net		$	—	$	1,060	$	(261)	$	1,345

At December 31, 2016, the Company had $124.0 million of deferred tax assets worldwide relating to net operating loss carryforwards, tax credit carryforwards and other temporary differences, which are available to reduce income taxes in future years. A valuation allowance must be established when it is “more likely than not” that all or a portion of deferred tax assets will not be realized. A review of all available positive and negative evidence needs to be considered, including a company’s performance, the market environment in which the company operates, length of carryback and carryforward periods, existing sales backlog, and projections of future operating results. Where there are cumulative losses in recent years there is a strong presumption that a valuation allowance is needed. This presumption can be overcome in very limited circumstances.

The Company maintains a valuation allowance reducing the carrying value of the deferred tax assets in the United States to zero. The Company will continue to maintain a full valuation allowance for those tax assets until sustainable future levels of profitability are evident. Changes in the valuation allowance in 2016 and 2015 were attributable to changes in the composition of temporary differences and changes in net operating loss carryforwards. The remaining net deferred tax asset on the consolidated balance sheet represents the balances related to the activities of the foreign subsidiaries.

At December 31, 2016, the Company has federal and state net operating loss carryforwards of $317.1 million and foreign net operating loss carryforwards of $2.8 million, expiring principally between 2017 and 2034.

The Company has research and development and other tax credit carryforwards of $12.8 million at December 31, 2016 that can be used to reduce future federal and state income tax liabilities. These tax credit carryforwards expire principally between 2017 and 2028. The Company does not have any foreign tax credit carryforwards as a result of the expiration of $3.6 million of foreign tax credits at December 31, 2016.

It is Company policy to provide taxes for the total anticipated tax impact of the undistributed earnings of our wholly‑owned foreign subsidiaries, as such earnings are not expected to be reinvested indefinitely. The Company anticipates that U.S. tax resulting from remitting such earnings will be offset by net operating loss or credit carryforwards to the extent available. In addition, the Company does not anticipate incurring a foreign withholding tax on remitting such earnings since it does not intend to remit the earnings as dividends.

The Company and its subsidiaries file income tax returns in the U.S. federal jurisdiction and various states and foreign jurisdictions. The Company and most foreign subsidiaries are subject to income tax examinations by tax authorities for all years dating back to 2005. The Company’s policy is to recognize interest related to unrecognized tax benefits as interest expense and penalties as operating expenses. The Company believes that it has appropriate support for the income tax positions taken and to be taken on its tax returns and that its accruals for tax liabilities are adequate for all open years based on an assessment of many factors including past experience and interpretations of tax law applied to the facts of each matter.

At December 31, 2016, the Company had unrecognized tax benefits related to uncertain tax positions of approximately $6.8 million, of which approximately $5.4 million reduced the Company’s deferred tax assets and the offsetting valuation allowance and $1.5 million was recorded in other long‑term liabilities. During the first quarter of 2016, the statute of limitations associated with a tax position previously taken by the Company expired. The related tax reserve of $0.6 million and accrued interest of $0.3 million that had been recorded were reversed during the twelve months ended December 31, 2016. The Company believes that it is reasonably possible that there will be a reduction to the reserve for uncertain tax positions of approximately $0.5 million within the next twelve months as a result of the expiration of the statute of limitations in a foreign tax jurisdiction. The Company recognized $0.2 million in interest and penalty expense related to unrecognized tax benefits for each of the years-ended December 31, 2016, 2015 and 2014, respectively.

A reconciliation of the beginning and ending balance of unrecognized tax benefits are as follows:


	2016		2015
	(in thousands)
Balance at beginning of year	$	7,671	$	7,960
Increase (decrease) in unrecognized tax benefits as a result of tax positions taken during a prior period		76		(78)
Decreases in unrecognized tax benefits related to settlements with tax authorities		—		(211)
Reductions to unrecognized tax benefits as a result of a lapse of the applicable statute of limitation		(903)
Increases in unrecognized tax benefits as a result of tax positions taken during the current period		—		—
Balance at end of year	$	6,844	$	7,671

Recorded as other long-term liability	$	1,462	$	2,142
Recorded as a decrease in deferred tax assets and offsetting valuation allowance		5,382		5,529
Balance at end of year	$	6,844	$	7,671

Quarterly Results of Operations (unaudited)

12 Months Ended

Dec. 31, 2016

Quarterly Results of Operations (unaudited)

Quarterly Results of Operations (unaudited)

Note 20. Quarterly Results of Operations (unaudited)


	Dec. 31,		Sept. 30,		June 30,		March 31,		Dec. 31,		Sept. 30,		June 30,		March 31,
	2016(1)		2016		2016		2016(2)		2015(3)		2015(4)		2015(5)		2015
	(in thousands, except per share data)
Revenue	$	69,358	$	65,650	$	64,451	$	67,521	$	70,458	$	79,317	$	78,437	$	73,283
Gross profit		26,947		24,104		25,131		23,415		21,973		29,179		27,174		23,380
Net income		3,965		2,151		2,937		1,948		826		6,101		5,883		1,868
Net income per basic share	$	0.13	$	0.07	$	0.10	$	0.07	$	0.03	$	0.21	$	0.21	$	0.07
Net income per diluted share	$	0.13	$	0.07	$	0.10	$	0.06	$	0.03	$	0.20	$	0.20	$	0.06

(1)

Net income includes a $0.6 million charge to inventory reserves.

(2)

Net income includes a $0.2 million charge to inventory reserves and $0.3 million restructuring charge.

(3)

Net income includes a $0.8 million charge to inventory reserves, $0.8 million variable incentive plan expense and $1.5 million of revenue for fully written down inventory sold in quarter.

(4)

Net income includes a $0.3 million charge to inventory reserves and $2.2 million variable incentive plan expense.

(5)

Net income includes a $0.3 million charge to inventory reserves, $1.1 million stock-based compensation acceleration and $2.3 million of revenue for fully written down inventory sold in quarter.

Schedule II-Valuation and Qualifying Account

12 Months Ended

Dec. 31, 2016

Schedule II-Valuation and Qualifying Accounts

Schedule II-Valuation and Qualifying Accounts

Schedule II—Valuation and Qualifying Accounts

Axcelis Technologies, Inc.

(In thousands)


	Balance at		Charged to						Balance at
	Beginning of		Costs and						End of
	Period		Expenses		Deductions		Other(*)		Period
Year ended December 31, 2016
Allowance for doubtful accounts and returns(**)	$	—	$	106	$	(29)	$	—	$	77
Reserve for excess and obsolete inventory(***)		10,465		1,051		(2,619)		—		8,897
Year ended December 31, 2015
Allowance for doubtful accounts and returns	$	390	$	—	$	(390)	$	—	$	—
Reserve for excess and obsolete inventory(***)		23,642		1,185		(14,362)		—		10,465
Year ended December 31, 2014
Allowance for doubtful accounts and returns	$	404	$	—	$	—	$	(14)	$	390
Reserve for excess and obsolete inventory(***)		25,091		1,003		(2,452)		—		23,642

(*) Represents foreign currency translation adjustments.

(**) Deductions include the write-off of accounts receivable.

(***) Deductions include the disposal and sale of fully reserved inventory

Summary of Significant Accounting Policies (Policies)

12 Months Ended

Dec. 31, 2016

Summary of Significant Accounting Policies

Basis of Presentation

(a) Basis of Presentation

Events occurring subsequent to December 31, 2016 have been evaluated for potential recognition or disclosure in the consolidated financial statements.

Use of Estimates

(b) Use of Estimates

Foreign Currency

Cash and Cash Equivalents

(d) Cash and Cash Equivalents

Inventories

(e) Inventories

Property, Plant and Equipment

(f) Property, Plant and Equipment

Property, plant and equipment are stated at cost, less accumulated depreciation and amortization.

Depreciation and amortization are recorded using the straight‑line method over the estimated useful lives of the related assets as follows:


Asset Classification	Estimated Useful Life
Land and buildings (under lease)		Lesser of the lease term or estimated useful life of the asset
Machinery and equipment		3 to 10 years

Repairs and maintenance costs are expensed as incurred. Expenditures for renewals and betterments are capitalized.

Impairment of Long-Lived Assets

(g) Impairment of Long‑Lived Assets

The Company did not have any indicators of impairment during the period ending December 31, 2016. The Company did not record an impairment charge in the years ended December 31, 2016, 2015, or 2014.

Concentration of Risk and Off-Balance Sheet Risk

(h) Concentration of Risk and Off‑Balance Sheet Risk

The Company has no significant off‑balance‑sheet risk such as exchange contracts, option contracts or other hedging arrangements.

Revenue Recognition

(i) Revenue Recognition

Shipping and Handling Costs

(j) Shipping and Handling Costs

Shipping and handling costs are included in cost of revenue.

Stock-Based Compensation

(k) Stock‑Based Compensation

See Note 14 for additional information relating to stock‑based compensation.

Income Taxes

(l) Income Taxes

Computation of Net Income (Loss) per Share

(m) Computation of Net Income (Loss) per Share

The components of net income (loss) per share are as follows:


	Year ended December 31,
	2016		2015		2014
	(in thousands, except per share data)
Net income (loss) available to common stockholders	$	11,001	$	14,678	$	(11,266)
Weighted average common shares outstanding used in computing basic income (loss) per share		29,195		28,595		27,862
Incremental options and RSUs		1,752		1,634		—
Weighted average common shares outstanding used in computing diluted net income (loss) per share		30,947		30,229		27,862
Net income (loss) per share
Basic	$	0.38	$	0.51	$	(0.40)
Diluted	$	0.36	$	0.49	$	(0.40)

Accumulated Other Comprehensive Income

(n) Accumulated Other Comprehensive Income

The following table presents the changes in accumulated other comprehensive income, net of tax, by component for the year ended December 31, 2016:


	Foreign		Defined benefit
	currency		pension plan		Total
	(in thousands)
Balance at December 31, 2015	$	(744)	$	(687)	$	(1,431)
Other comprehensive loss and pension reclassification		(847)		(1)		(848)
Balance at December 31, 2016	$	(1,591)	$	(688)	$	(2,279)

Recent Accounting Guidance

(o) Recent Accounting Guidance

Accounting Standards or Updates Recently Adopted

Accounting Standards or Updates Not Yet Effective

Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2016

Summary of Significant Accounting Policies

Schedule of estimated useful lives of the related assets


Asset Classification	Estimated Useful Life
Land and buildings (under lease)		Lesser of the lease term or estimated useful life of the asset
Machinery and equipment		3 to 10 years

Schedule of components of net (loss) per share


	Year ended December 31,
	2016		2015		2014
	(in thousands, except per share data)
Net income (loss) available to common stockholders	$	11,001	$	14,678	$	(11,266)
Weighted average common shares outstanding used in computing basic income (loss) per share		29,195		28,595		27,862
Incremental options and RSUs		1,752		1,634		—
Weighted average common shares outstanding used in computing diluted net income (loss) per share		30,947		30,229		27,862
Net income (loss) per share
Basic	$	0.38	$	0.51	$	(0.40)
Diluted	$	0.36	$	0.49	$	(0.40)

Schedule of changes in accumulated other comprehensive income, net of tax


	Foreign		Defined benefit
	currency		pension plan		Total
	(in thousands)
Balance at December 31, 2015	$	(744)	$	(687)	$	(1,431)
Other comprehensive loss and pension reclassification		(847)		(1)		(848)
Balance at December 31, 2016	$	(1,591)	$	(688)	$	(2,279)

Correction of Accounting Error in Prior Period (Tables)

12 Months Ended

Dec. 31, 2016

Correction of Accounting Error in Prior Period

Schedule of Effect of Error Corrections and Prior Period Adjustments


(in thousands)	Previously Reported December 31, 2015			Adjusted December 31, 2015	Effect of Change
Inventory, net	$	115,904	$	109,408	$	(6,496)
Total current assets		236,453		229,957		(6,496)
Total assets		288,280		281,784		(6,496)
Accumulated deficit		(336,209)		(342,705)		(6,496)
Total stockholders' equity		190,260		183,764		(6,496)
Total liabilities and stockholders' equity	$	288,280	$	281,784	$	(6,496)

Accounts Receivable, net (Tables)

12 Months Ended

Dec. 31, 2016

Accounts Receivable, net

Schedule of components of accounts receivable


	December 31,
	2016		2015
	(in thousands)
Trade receivables	$	50,650	$	36,868
Allowance for doubtful accounts		(77)		—
Trade receivables, net	$	50,573	$	36,868

Inventories, net (Tables)

12 Months Ended

Dec. 31, 2016

Inventories, net

Schedule of components of inventories


	December 31,
	2016		2015
	(in thousands)
Raw materials	$	80,503	$	72,070
Work in process		14,117		29,219
Finished goods (completed systems)		19,233		8,119
Inventories, net	$	113,853	$	109,408

Property, Plant and Equipment, net (Tables)

12 Months Ended

Dec. 31, 2016

Property, Plant and Equipment, net.

Schedule of components of property, plant and equipment


	December 31,
	2016		2015
	(in thousands)
Land and buildings	$	75,792	$	80,491
Machinery and equipment		9,472		11,080
Construction in process		1,704		1,451
Total cost		86,968		93,022
Accumulated depreciation		(56,128)		(62,991)
Property, plant and equipment, net	$	30,840	$	30,031

Assets Manufactured for Internal Use, net (Tables)

12 Months Ended

Dec. 31, 2016

Assets Manufactured for Internal Use, net

Schedule of components of assets manufactured for internal use


	December 31,
	2016		2015
	(in thousands)
Internal use assets	$	42,776	$	31,759
Construction in process		1,745		470
Total cost		44,521		32,229
Accumulated depreciation		(22,838)		(20,193)
Assets manufactured for internal use, net	$	21,683	$	12,036

Restructuring Charges (Tables)

12 Months Ended

Dec. 31, 2016

Restructuring Charges.

Schedule of changes in restructuring liability


	Severance
	(in thousands)
Balance at December 31, 2014	$	481
Severance, related costs and other adjustments		(2)
Cash payments		(479)
Balance at December 31, 2015	$	—
Severance and related costs		282
Cash payments		(282)
Balance at December 31, 2016	$	—

Product Warranty (Tables)

12 Months Ended

Dec. 31, 2016

Product Warranty

Schedule of product warranty liability



	Year ended December 31,
	2016		2015		2014
	(in thousands)
Balance at January 1 (beginning of year)	$	3,555	$	1,526	$	1,428
Warranties issued during the period		3,125		4,305		1,743
Settlements made during the period		(4,249)		(2,672)		(2,096)
Changes in estimate of liability for pre-existing warranties during the period		235		396		451
Balance at December 31 (end of period)	$	2,666	$	3,555	$	1,526

Amount classified as current	$	2,426	$	3,363	$	1,352
Amount classified as long-term		240		192		174
Total warranty liability	$	2,666	$	3,555	$	1,526

Employee Benefit Plans (Tables)

12 Months Ended

Dec. 31, 2016

Employee Benefit Plans

Schedule of classification of liabilities in Consolidated Balance Sheets


	Year ended
	December 31,
	2016		2015
	(in thousands)
Current:
Accrued compensation	$	902	$	857
Total current liabilities	$	902	$	857
Long-term:
Other long-term liabilities		3,057		3,052
Total liabilities	$	3,959	$	3,909

Stock Award Plans and Stock Based Compensation (Tables)

12 Months Ended

Dec. 31, 2016

Stock-Based Compensation

Schedule of estimated weighted-average assumptions used in calculation of fair value of options granted


	Year ended December 31,
	2016	2015	2014
Weighted-average expected volatility	49.3% — 56.7%	56.2% — 64.7%	60.6% — 98.4%
Weighted-average expected term	4.7 years	4.6 — 4.7 years	3.8 — 4.7 years
Risk-free interest rate	1.1% — 2.0%	1.3% — 1.6%	1.2% — 1.7%
Expected dividend yield	0%	0%	0%

Summary of stock option activity


				Weighted
		Weighted		Average
		Average		Remaining	Aggregate
		Exercise		Contractual	Intrinsic
	Options	Price		Term	Value
	(in thousands)			(years)	(in thousands)
Outstanding at December 31, 2015	5,417	$	7.29
Granted	42		13.34
Exercised	(392)		5.71
Canceled	(56)		8.98
Expired	(60)		20.66
Outstanding at December 31, 2016	4,951	$	7.29	3.94	$	36,018
Exercisable at December 31, 2016	3,756	$	6.49	3.63	$	30,321
Options Vested or Expected to Vest at December 31, 2016(1)	4,886	$	7.25	3.97	$	35,743

Schedule of changes in the Company's non-vested restricted stock units


		Weighted-Average
		Grant Date Fair
	Shares/units	Value per Share
	(in thousands)
Outstanding at December 31, 2015	91	$	11.39
Granted	571		9.73
Vested	(110)		10.50
Forfeited	(4)		9.64
Outstanding at December 31, 2016	548	$	9.85

Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 2016

Fair Value Measurements

Schedule of Company's assets and liabilities by level within the fair value hierarchy


	December 31, 2016
	Fair Value Measurements
	Level 1		Level 2		Level 3		Total
	(in thousands)
Assets
Cash equivalents:
Money market funds	$	54,170	$	—	$	—	$	54,170


	December 31, 2015
	Fair Value Measurements
	Level 1		Level 2		Level 3		Total
	(in thousands)
Assets
Cash equivalents:
Money market funds	$	65,327	$	—	$	—	$	65,327
Liabilities
Sale leaseback obligation	$	—	$	—	$	47,586	$	47,586

Commitments and Contingencies (Tables)

12 Months Ended

Dec. 31, 2016

Contingencies

Schedule of future minimum lease commitments on non-cancelable operating leases

Future minimum lease commitments on non‑cancelable operating leases for the year ended December 31, 2016 are as follows:


	Operating
	Leases
	(in thousands)
2017	$	2,581
2018		1,390
2019		704
2020		352
2021		201
Thereafter		—
	$	5,228

Cash payment schedule associated with lease obligation

The following table relates to the cash payment schedule associated with this lease obligation as of December 31, 2016:


	Lease
	Obligation
	(in thousands)
2017	$	5,315
2018		5,470
2019		5,594
2020		5,719
2021		5,848
Thereafter		97,999
Total lease payments	$	125,945
Less interest portion		(78,359)
Sale leaseback obligation	$	47,586

Business Segment and Geographic Region Information (Tables)

12 Months Ended

Dec. 31, 2016

Business Segment and Geographic Region Information

Schedule of revenue by product lines


	Year ended December 31,
	2016		2015		2014
	(in thousands)
Ion implantation systems and services	$	248,885	$	282,624	$	183,148
Other systems and services		18,095		18,871		19,903
Total revenue	$	266,980	$	301,495	$	203,051

Schedule of revenue and long-lived assets by geographic region


			Long-Lived
	Revenue		Assets
	(in thousands)
2016
United States	$	191,261	$	52,006
Europe		25,436		—
Asia Pacific		50,283		517
	$	266,980	$	52,523
2015
United States	$	226,890	$	41,729
Europe		24,209		—
Asia Pacific		50,396		334
	$	301,495	$	42,063
2014
United States	$	126,255	$	40,001
Europe		29,140		—
Asia Pacific		47,656		299
	$	203,051	$	40,300

Income Taxes (Tables)

12 Months Ended

Dec. 31, 2016

Income Taxes

Schedule of loss before income taxes


	Year ended December 31,
	2016		2015		2014
	(in thousands)
United States	$	8,880	$	12,708	$	(11,987)
Foreign		2,144		2,497		1,820
Income (loss) before income taxes	$	11,024	$	15,205	$	(10,167)

Schedule of provision for income taxes


	Year ended December 31,
	2016		2015		2014
	(in thousands)
Current:
United States
Federal	$	—	$	—	$	—
State		49		(33)		59
Foreign		(217)		374		780
Total current		(168)		341		839
Deferred:
Foreign		191		186		260
Total deferred		191		186		260
Income tax provision	$	23	$	527	$	1,099

Schedule of reconciliations of income taxes at the United States Federal statutory rate to the effective income tax rate


	Year ended December 31,
	2016		2015		2014
	(in thousands)
Income tax benefit at the United States statutory rate	$	3,859	$	5,322	$	(3,558)
State income taxes		32		(22)		38
Unrecognized tax benefits		(615)		(174)		184
Effect of change in valuation allowance		(7,765)		(5,676)		(6,835)
Foreign income tax rate differentials		233		600		259
Unremitted earnings of foreign subsidiaries		305		(102)		(758)
Stock options		264		379		686
Credit expirations		3,565		—		—
Deemed distribution from foreign subsidiaries		—		—		607
Discrete items, net		—		(540)		9,143
Other, net		145		740		1,333
Income tax provision	$	23	$	527	$	1,099

Schedule of significant components of current and long-term deferred income taxes


	`	As of December 31,
		2016				2015
		Current		Long Term		Current		Long Term
		(in thousands)
Federal net operating loss carryforwards		$	—	$	98,007	$	—	$	101,479
State net operating loss carryforwards			—		1,546		—		1,636
Foreign net operating loss carryforwards			—		673		—		810
Federal tax credit carryforwards			—		12,778		—		16,343
State tax credit carryforwards			—		2,566		—		3,964
Unremitted earnings of foreign subsidiaries			—		(8,913)		—		(8,632)
Intangible assets			—		229		—		286
Property, plant and equipment			—		9,774		—		9,331
Accrued compensation			—		97		1,082		—
Inventories			—		5,230		2,541		—
Stock compensation			—		6,687		—		6,001
Warranty			—		930		1,214		—
Other			—		(5,578)		1,237		(3,945)
Deferred taxes, gross			—		124,026		6,074		127,273
Valuation allowance			—		(122,966)		(6,335)		(125,928)
Deferred taxes, net		$	—	$	1,060	$	(261)	$	1,345

Schedule of reconciliation of the beginning and ending balance of unrecognized tax benefits


	2016		2015
	(in thousands)
Balance at beginning of year	$	7,671	$	7,960
Increase (decrease) in unrecognized tax benefits as a result of tax positions taken during a prior period		76		(78)
Decreases in unrecognized tax benefits related to settlements with tax authorities		—		(211)
Reductions to unrecognized tax benefits as a result of a lapse of the applicable statute of limitation		(903)
Increases in unrecognized tax benefits as a result of tax positions taken during the current period		—		—
Balance at end of year	$	6,844	$	7,671

Recorded as other long-term liability	$	1,462	$	2,142
Recorded as a decrease in deferred tax assets and offsetting valuation allowance		5,382		5,529
Balance at end of year	$	6,844	$	7,671

Quarterly Results of Operations (unaudited) (Tables)

12 Months Ended

Dec. 31, 2016

Quarterly Results of Operations (unaudited)

Schedule of quarterly results of operations


	Dec. 31,		Sept. 30,		June 30,		March 31,		Dec. 31,		Sept. 30,		June 30,		March 31,
	2016(1)		2016		2016		2016(2)		2015(3)		2015(4)		2015(5)		2015
	(in thousands, except per share data)
Revenue	$	69,358	$	65,650	$	64,451	$	67,521	$	70,458	$	79,317	$	78,437	$	73,283
Gross profit		26,947		24,104		25,131		23,415		21,973		29,179		27,174		23,380
Net income		3,965		2,151		2,937		1,948		826		6,101		5,883		1,868
Net income per basic share	$	0.13	$	0.07	$	0.10	$	0.07	$	0.03	$	0.21	$	0.21	$	0.07
Net income per diluted share	$	0.13	$	0.07	$	0.10	$	0.06	$	0.03	$	0.20	$	0.20	$	0.06

(1)

Net income includes a $0.6 million charge to inventory reserves.

(2)

Net income includes a $0.2 million charge to inventory reserves and $0.3 million restructuring charge.

(3)

Net income includes a $0.8 million charge to inventory reserves, $0.8 million variable incentive plan expense and $1.5 million of revenue for fully written down inventory sold in quarter.

(4)

Net income includes a $0.3 million charge to inventory reserves and $2.2 million variable incentive plan expense.

Net income includes a $0.3 million charge to inventory reserves, $1.1 million stock-based compensation acceleration and $2.3 million of revenue for fully written down inventory sold in quarter.

Summary of Significant Accounting Policies (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Foreign Currency
Foreign exchange losses (gains) realized	$ (0.6)	$ 0.0	$ 1.8

Summary of Significant Accounting Policies - Property, Plant and Equipment (Details) - USD ($) $ in Millions		12 Months Ended
	Jan. 30, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Impairment of Long-Lived Assets
Impairment of long-lived assets		$ 0.0	$ 0.0	$ 0.0
Machinery and equipment \| Minimum
Property, plant and equipment, net
Useful life		3 years
Machinery and equipment \| Maximum
Property, plant and equipment, net
Useful life		10 years
Beverly Property Owner LLC \| Sale leaseback obligation \| Land and buildings
Property, plant and equipment, net
Lease term	22 years

Summary of Significant Accounting Policies - Concentration of Risk (Details) - item	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Revenue \| Customer concentration risk
Concentration of risk
Number of customers	1	2	2
Revenue \| Customer concentration risk \| Ten largest customers
Concentration of risk
Number of customers	10	10	10
Percentage of concentration risk	70.20%	76.80%	68.10%
Revenue \| Customer concentration risk \| One customer
Concentration of risk
Percentage of concentration risk	17.00%	29.30%	17.40%
Revenue \| Customer concentration risk \| Second customer
Concentration of risk
Percentage of concentration risk		10.50%	12.30%
Consolidated accounts receivable \| Credit concentration risk
Concentration of risk
Number of customers	4	3
Consolidated accounts receivable \| Credit concentration risk \| One customer
Concentration of risk
Percentage of concentration risk	22.00%	22.90%
Consolidated accounts receivable \| Credit concentration risk \| Second customer
Concentration of risk
Percentage of concentration risk	12.30%	12.70%
Consolidated accounts receivable \| Credit concentration risk \| Third customer
Concentration of risk
Percentage of concentration risk	12.00%	11.60%
Consolidated accounts receivable \| Credit concentration risk \| Fourth customer
Concentration of risk
Percentage of concentration risk	10.60%

Summary of Significant Accounting Policies - Net Loss per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Revenue recognition
Maximum deferral period from shipment for recognition of systems revenue and related costs									12 months
Incremental shares excluded from the calculation of net loss per share (in shares)										1,165,855
Net income (loss) per share:
Net income (loss) available to common stockholders	$ 3,965	$ 2,151	$ 2,937	$ 1,948	$ 826	$ 6,101	$ 5,883	$ 1,868	$ 11,001	$ 14,678	$ (11,266)
Weighted average common shares outstanding used in computing basic income (loss) per share									29,195,000	28,595,000	27,862,000
Weighted average common shares outstanding used in computing diluted net income (loss) per share									30,947,000	30,229,000	27,862,000
Net income (loss) per share
Basic	$ 0.13	$ 0.07	$ 0.10	$ 0.07	$ 0.03	$ 0.21	$ 0.21	$ 0.07	$ 0.38	$ 0.51	$ (0.40)
Diluted	$ 0.13	$ 0.07	$ 0.10	$ 0.06	$ 0.03	$ 0.20	$ 0.20	$ 0.06	$ 0.36	$ 0.49	$ (0.40)
Restricted Stock
Net income (loss) per share:
Incremental options and RSUs									1,752,000	1,634,000

Summary of Significant Accounting Policies - Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Changes in accumulated other comprehensive income, net of tax
Balance at the beginning of period	$ (1,431)
Other comprehensive loss and pension reclassification	(848)	$ (2,707)	$ (4,463)
Balance at the end of period	(2,279)	(1,431)
Foreign currency
Changes in accumulated other comprehensive income, net of tax
Balance at the beginning of period	(744)
Other comprehensive loss and pension reclassification	(847)
Balance at the end of period	(1,591)	(744)
Defined benefit pension plan
Changes in accumulated other comprehensive income, net of tax
Balance at the beginning of period	(687)
Other comprehensive loss and pension reclassification	(1)
Balance at the end of period	$ (688)	$ (687)

- Definition

Accumulated change in equity from transactions and other events and circumstances from non-owner sources, net of tax effect, at period end. Excludes Net Income (Loss), and accumulated changes in equity from transactions resulting from investments by owners and distributions to owners. Includes foreign currency translation items, certain pension adjustments, unrealized gains and losses on certain investments in debt and equity securities, other than temporary impairment (OTTI) losses related to factors other than credit losses on available-for-sale and held-to-maturity debt securities that an entity does not intend to sell and it is not more likely than not that the entity will be required to sell before recovery of the amortized cost basis, as well as changes in the fair value of derivatives related to the effective portion of a designated cash flow hedge.

+ References + Details

Summary of Significant Accounting Policies - Recent Accounting Guidance (Details) - New Accounting Pronouncement, Early Adoption, Effect - ASU No. 2015-17 $ in Millions	Dec. 31, 2016 USD ($)
Recent Accounting Guidance
Current deferred tax assets	$ (0.2)
Long-term deferred tax assets	(0.3)
Current deferred tax assets	$ (0.5)

Correction of Accounting Error in Prior Period - (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Error Corrections and Prior Period Adjustments Restatement
Inventory, Net	$ 113,853	$ 109,408
Total current assets	240,729	229,957
Total assets	302,231	281,784
Accumulated deficit	(331,704)	(342,705)
Total stockholders' equity	201,455	183,764	$ 161,856	$ 169,506
Total liabilities and stockholders' equity	$ 302,231	281,784
Previously Reported
Error Corrections and Prior Period Adjustments Restatement
Inventory, Net		115,904
Total current assets		236,453
Total assets		288,280
Accumulated deficit		(336,209)
Total stockholders' equity		190,260
Total liabilities and stockholders' equity		288,280
Adjusted
Error Corrections and Prior Period Adjustments Restatement
Inventory, Net		109,408
Total current assets		229,957
Total assets		281,784
Accumulated deficit		(342,705)
Total stockholders' equity		183,764
Total liabilities and stockholders' equity		281,784
Effect of Change
Error Corrections and Prior Period Adjustments Restatement
Inventory, Net		(6,496)
Total current assets		(6,496)
Total assets		(6,496)
Accumulated deficit		(6,496)
Total stockholders' equity		(6,496)
Total liabilities and stockholders' equity		$ (6,496)

1-for-4 Reverse Stock Split -(Details) shares in Thousands	12 Months Ended
1-for-4 Reverse Stock Split -(Details) shares in Thousands	Dec. 31, 2016 $ / shares shares	Dec. 31, 2015 $ / shares	May 02, 2012 $ / shares
Class of Stock [Line Items]
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001	$ 0.001
Treasury Stock, Shares, Retired \| shares	30
Common Stock
Class of Stock [Line Items]
Reverse stock split conversion ratio	0.25
Common stock, par value (in dollars per share)	$ 0.001

Restricted Cash (Details) $ in Millions	Dec. 31, 2016 USD ($)
Workers' Compensation Liability	$ 0.9
Deposit related to customs activity	0.1
Revolving credit facility
Availability used to support outstanding letters of credit	6.9
Revolving credit facility \| Sale leaseback obligation
Security Deposit	$ 5.9

Accounts Receivable, net (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Accounts Receivable, net
Trade receivables	$ 50,650	$ 36,868
Allowance for doubtful accounts	(77)
Trade receivable, net	$ 50,573	$ 36,868

Inventories, net - Components (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Inventories, net
Raw materials	$ 80,503	$ 72,070
Work in process	14,117	29,219
Finished goods (completed systems)	19,233	8,119
Inventories, net	$ 113,853	$ 109,408

Inventories, net - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Mar. 31, 2016	Sep. 30, 2015	Jun. 30, 2015
Inventories, net additional information
Inventory reserves	$ 600	$ 800		$ 200	$ 300	$ 300
Charges to cost of sales due to below normal production capacity			$ 1,000
Charges to cost of sales due to lower of cost or market value	800	500	800
Inventory reserves
Inventories, net additional information
Decrease in inventory reserves	2,619	14,362	2,452
Reduction in inventory reserves	1,600
Provision charge to reserve	1,051	1,185	$ 1,003
Inventory reserves	$ 8,800	$ 10,500

Property, Plant and Equipment, net (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Property, plant and equipment, net
Gross	$ 86,968	$ 93,022
Accumulated depreciation	(56,128)	(62,991)
Net	30,840	30,031
Depreciation expense	1,800	2,400	$ 2,400
Land and buildings
Property, plant and equipment, net
Gross	75,792	80,491
Machinery and equipment
Property, plant and equipment, net
Gross	9,472	11,080
Construction in process
Property, plant and equipment, net
Gross	$ 1,704	$ 1,451

Assets Manufactured for Internal Use, net - Components (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Assets manufactured for internal use
Cost	$ 86,968	$ 93,022
Accumulated depreciation	(56,128)	(62,991)
Net	30,840	30,031
Depreciation expense	1,800	2,400	$ 2,400
Assets Manufactured for Internal Use
Assets manufactured for internal use
Cost	44,521	32,229
Accumulated depreciation	(22,838)	(20,193)
Net	21,683	12,036
Depreciation expense	2,400	2,500	$ 2,200
Assets Manufactured for Internal Use \| Internal use assets
Assets manufactured for internal use
Cost	42,776	31,759
Assets Manufactured for Internal Use \| Construction in process.
Assets manufactured for internal use
Cost	$ 1,745	$ 470

Restructuring Charges (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
Restructuring Charges (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Changes in restructuring liability
Severance and related costs	$ 300	$ 282	$ 18	$ 2,621
Severance
Changes in restructuring liability
Balance at the beginning of the period			481
Severance and related costs		282	(2)
Cash payments		$ (282)	$ (479)
Balance at the end of the period				$ 481

Product Warranty (Details) - USD ($) $ in Thousands	12 Months Ended
Product Warranty (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Product Warranty
Product warranty period	1 year
Changes in standard product warranty liability
Balance at the beginning of the period	$ 3,555	$ 1,526	$ 1,428
Warranties issued during the period	3,125	4,305	1,743
Settlements made during the period	(4,249)	(2,672)	(2,096)
Changes in estimate of liability for pre-existing warranties during the period	235	396	451
Balance at the end of the period	2,666	3,555	1,526
Product warranty classification
Amount classified as current				$ 2,426	$ 3,363	$ 1,352
Amount classified as long-term				240	192	174
Total warranty liability	$ 3,555	$ 1,526	$ 1,428	$ 2,666	$ 3,555	$ 1,526

Financing Arrangements (Details) - USD ($) $ in Thousands	Jan. 30, 2015	Dec. 31, 2016	Dec. 31, 2015
Financing Arrangements
Sale leaseback obligation		$ 47,586	$ 47,586
Sale leaseback obligation \| Land and buildings \| Beverly Property Owner LLC
Financing Arrangements
Purchase price	$ 48,900
Lease term	22 years
Sale leaseback obligation		$ 47,600
Security deposit	$ 5,900

Employee Benefit Plans - Defined Contribution Plan (Details) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Defined Contribution Plan
Employer contributed by eligible participants	50.00%
Defined contribution plan expenses	$ 400,000	$ 400,000
Maximum
Defined Contribution Plan
Defined Contribution Plan, Employer Discretionary Contribution Amount	$ 1,200	$ 1,000
Regular employees
Defined Contribution Plan
Maximum contribution per employee under the Axcelis Long-Term Investment Plan (as a percent)	35.00%
Highly compensated employees
Defined Contribution Plan
Maximum contribution per employee under the Axcelis Long-Term Investment Plan (as a percent)	16.00%

Employee Benefit Plans - Other Compensation Plans (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Classification of liabilities in the Consolidated Balance Sheets
Current liabilities	$ 902	$ 857
Total liabilities	3,959	3,909
Plan expenses	800	700	$ 700
Accrued compensation
Classification of liabilities in the Consolidated Balance Sheets
Current liabilities	902	857
Other long-term liabilities
Classification of liabilities in the Consolidated Balance Sheets
Long-term liabilities	$ 3,057	$ 3,052

Stock Award Plans and Stock Based Compensation (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended			36 Months Ended	56 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2016	Dec. 31, 2016	May 02, 2012
Stock-based compensation
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001		$ 0.001	$ 0.001	$ 0.001
Stock-Based Compensation Expense
Forfeiture rate (as a percent)	5.00%	5.00%	5.00%
Stock-based compensation expense	$ 5,200	$ 5,600	$ 4,800
Employee stock purchase plan
Stock-based compensation
Number of shares of common stock available for future grant	300,000			300,000	300,000
Employee Stock Purchase Plan
Purchase price as a percentage of the market value of a common stock on the day the stock is purchased	85.00%
Offering period over which compensation expense is amortized	6 months
Stock-Based Compensation Expense
Stock-based compensation expense	$ 100	$ 100	$ 100
Employee stock purchase plan \| Maximum
Employee Stock Purchase Plan
Payroll deductions as a percentage of employee's salary	10.00%
Number of shares purchased under the plan	100,000	100,000	100,000
Restricted stock and restricted stock units
Shares/units
Outstanding at the beginning of the period (in shares)	91,000
Granted (in shares)	571,000
Vested (in shares)	(110,000)
Forfeited (in shares)	(4,000)
Outstanding at the end of the period (in shares)	548,000	91,000		548,000	548,000
Weighted-Average Grant Date Fair Value per Share
Outstanding at the beginning of the period (in dollars per share)	$ 11.39
Granted (in dollars per share)	9.73	$ 12.12	$ 8.68
Vested (in dollars per share)	10.50
Forfeited (in dollars per share)	9.64
Outstanding at the end of the period (in dollars per share)	$ 9.85	$ 11.39		$ 9.85	$ 9.85
Stock Options
Options
Outstanding at the beginning of the period (in shares)	5,417,000
Granted (in shares)	42,000
Exercised (in shares)	(392,000)
Canceled (in shares)	(56,000)
Expired (in shares)	(60,000)
Outstanding at the end of the period (in shares)	4,951,000	5,417,000		4,951,000	4,951,000
Exercisable (in shares)	3,756,000			3,756,000	3,756,000
Options Vested or Expected to Vest at the end of the period (in shares)	4,886,000			4,886,000	4,886,000
Weighted Average Exercise Price
Outstanding at the beginning of the period (in dollars per share)	$ 7.29
Granted (in dollars per share)	13.34
Exercised (in dollars per share)	5.71
Canceled (in dollars per share)	8.98
Expired (in dollars per share)	20.66
Outstanding at the end of the period (in dollars per share)	7.29	$ 7.29		$ 7.29	$ 7.29
Exercisable at the end of the period (in dollars per share)	6.49			6.49	6.49
Options Vested or Expected to Vest at the end of the period (in dollars per share)	$ 7.25			$ 7.25	$ 7.25
Weighted Average Remaining Contractual Term
Outstanding at the end of the period	3 years 11 months 9 days
Exercisable at the end of the period	3 years 7 months 17 days
Options Vested or Expected to Vest at the end of the period	3 years 11 months 19 days
Aggregate Intrinsic Value
Outstanding at the end of the period (in dollars)	$ 36,018			$ 36,018	$ 36,018
Exercisable at the end of the period (in dollars)	30,321			30,321	30,321
Options Vested or Expected to Vest at the end of the period (in dollars)	35,743			35,743	35,743
Additional disclosure
Total intrinsic value of options exercised (in dollars)	2,500	$ 5,300	$ 2,400
Total fair value of stock options vested (in dollars)	$ 3,900	$ 5,400	$ 4,700
Weighted average grant fair value of options granted (in dollars per share)	$ 5.75	$ 5.05	$ 3.82
Total forfeiture adjusted unrecognized compensation cost (in dollars)	$ 4,800			$ 4,800	$ 4,800
Weighted-average period over which unrecognized compensation cost is expected to be recognized	2 years 1 month 6 days
Stock Options \| Employees
Stock-based compensation
Vesting period	4 years
Period after termination to exercise awards that were vested	90 days
Period after termination to retiring employees to exercise vested awards	1 year
Stock Options \| Non-employee members of Board of Directors
Stock-based compensation
Vesting period	6 months
Restricted Stock
Shares/units
Granted (in shares)	0	0	0
Vested (in shares)	0	0	0
Stock Options and Restricted Stock Units
Estimated weighted-average assumptions
Weighted-average expected term	4 years 8 months 12 days
Risk-free interest rate, minimum (as a percent)	1.10%	1.30%	1.20%
Risk-free interest rate, maximum (as a percent)	2.00%	1.60%	1.70%
Expected dividend yield (as a percent)	0.00%	0.00%	0.00%
Stock Options and Restricted Stock Units \| Minimum
Estimated weighted-average assumptions
Weighted-average expected volatility (as a percent)	49.30%	56.20%	60.60%
Weighted-average expected term		4 years 7 months 6 days	3 years 9 months 18 days
Stock Options and Restricted Stock Units \| Maximum
Estimated weighted-average assumptions
Weighted-average expected volatility (as a percent)	56.70%	64.70%	98.40%
Weighted-average expected term		4 years 8 months 12 days	4 years 8 months 12 days
2000 Stock Plan
Stock-based compensation
Awards granted (in shares)					0
Number of shares of common stock available for future grant	0			0	0
2000 Stock Plan \| Stock Options
Stock-based compensation
Expiration period	10 years
2012 Equity Incentive Plan
Stock-based compensation
Number of shares of common stock originally reserved for future grant						5,500,000
Number of shares of common stock available for future grant	700,000			700,000	700,000
2012 Equity Incentive Plan \| Stock Options
Stock-based compensation
Expiration period	7 years
2012 Equity Incentive Plan \| Restricted Stock
Shares/units
Granted (in shares)				0
2012 Equity Incentive Plan \| Stock Options and Restricted Stock Units
Estimated weighted-average assumptions
Weighted-average expected term	7 years

Stockholders' Equity (Details) - shares shares in Thousands	Dec. 31, 2016	Dec. 31, 2015
Stockholders' Equity
Number of shares of preferred stock that the entity is authorized to issue	30,000	30,000
Preferred stock, shares outstanding	0	0

Fair Value Measurements (Details) - USD ($) $ in Thousands	12 Months Ended
Fair Value Measurements (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Recurring \| Total \| Sale leaseback obligation
Assets and Liabilities Measured at Fair Value
Sale leaseback obligation		$ 47,586
Recurring \| Total \| Money market funds
Assets and Liabilities Measured at Fair Value
Money market funds	$ 54,170	65,327
Recurring \| Level 1 \| Money market funds
Assets and Liabilities Measured at Fair Value
Money market funds	$ 54,170	65,327
Recurring \| Level 3 \| Sale leaseback obligation
Assets and Liabilities Measured at Fair Value
Sale leaseback obligation		$ 47,586
Land and buildings \| Beverly Property Owner LLC \| Sale leaseback obligation
Assets and Liabilities Measured at Fair Value
Implicit interest rate on associated cash flows	10.65%

Commitments and Contingencies (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Lease Commitments
Rental expense under operating leases	$ 3,800	$ 3,800	$ 3,700
Future minimum lease commitments on non-cancelable operating leases
2017	2,581
2018	1,390
2019	704
2020	352
2021	201
Total	5,228
Cash payment schedule associated with lease obligation
2017	5,315
2018	5,470
2019	5,594
2020	5,719
2021	5,848
Thereafter	97,999
Total lease payments	125,945
Less interest portion	(78,359)
Sales leaseback obligation	47,586	$ 47,586
Purchase Commitments
Non-cancelable contracts and purchase orders for inventory	$ 43,900

Business Segment and Geographic Region Information - Number of Segments (Details)	12 Months Ended
	Dec. 31, 2016 item
Business Segment and Geographic Region Information
Number of business segments	1

Business Segment and Geographic Region Information - Revenue by Product Line (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Revenue by product lines
Revenue	$ 69,358	$ 65,650	$ 64,451	$ 67,521	$ 70,458	$ 79,317	$ 78,437	$ 73,283	$ 266,980	$ 301,495	$ 203,051
Ion implantation systems services
Revenue by product lines
Revenue									248,885	282,624	183,148
Other systems and services
Revenue by product lines
Revenue									$ 18,095	$ 18,871	$ 19,903

Business Segment and Geographic Region Information - Revenue and Long-Lived Assets (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Revenue and long-lived assets by geographic region
Revenue	$ 69,358	$ 65,650	$ 64,451	$ 67,521	$ 70,458	$ 79,317	$ 78,437	$ 73,283	$ 266,980	$ 301,495	$ 203,051
Long-Lived Assets	52,523				42,063				52,523	42,063	40,300
United States.
Revenue and long-lived assets by geographic region
Revenue									191,261	226,890	126,255
Long-Lived Assets	52,006				41,729				52,006	41,729	40,001
Europe
Revenue and long-lived assets by geographic region
Revenue									25,436	24,209	29,140
Asia Pacific
Revenue and long-lived assets by geographic region
Revenue									50,283	50,396	47,656
Long-Lived Assets	$ 517				$ 334				517	334	299
International \| Revenue \| Geographic concentration risk
Revenue and long-lived assets by geographic region
Revenue									$ 213,800	$ 256,500	$ 162,400
Percentage of revenue									80.00%	85.10%	80.00%

Income Taxes - Tax Effects (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income (loss) before income taxes
United States	$ 8,880	$ 12,708	$ (11,987)
Foreign	2,144	2,497	1,820
Income (loss) before income taxes	11,024	15,205	(10,167)
Current:
State	49	(33)	59
Foreign	(217)	374	780
Total current	(168)	341	839
Deferred:
Foreign	191	186	260
Total deferred	191	186	260
Income tax provision	23	527	1,099
Reconciliations of income taxes at the United States Federal statutory rate to the effective income tax rate
Income tax benefit at the United States statutory rate	3,859	5,322	(3,558)
State income taxes	32	(22)	38
Unrecognized tax benefits	(615)	(174)	184
Effect of change in valuation allowance	(7,765)	(5,676)	(6,835)
Foreign income tax rate differentials	233	600	259
Unremitted earnings of foreign subsidiaries	305	(102)	(758)
Stock options	264	379	686
Credit expirations	3,565
Deemed distribution from foreign subsidiaries			607
Discrete items, net		(540)	9,143
Other, net	145	740	1,333
Income tax provision	23	527	$ 1,099
Significant components of current deferred income taxes
Accrued compensation		1,082
Inventories		2,541
Warranty		1,214
Other		1,237
Deferred taxes, gross		6,074
Valuation allowance		(6,335)
Deferred taxes, net		(261)
Significant components of long-term deferred income taxes
Federal net operating loss carryforwards	98,007	101,479
State net operating loss carryforwards	1,546	1,636
Foreign net operating loss carryforwards	673	810
Federal tax credit carryforwards	12,778	16,343
State tax credit carryforwards	2,566	3,964
Unremitted earnings of foreign subsidiaries	(8,913)	(8,632)
Intangible assets	229	286
Property, plant and equipment	9,774	9,331
Accrued compensation	97
Inventories	5,230
Stock compensation	6,687	6,001
Warranty	930
Other	(5,578)	(3,945)
Deferred taxes, gross	124,026	127,273
Valuation allowance	(122,966)	(125,928)
Deferred taxes, net	$ 1,060	$ 1,345

Income Taxes - Valuation Allowance (Details) $ in Thousands	Dec. 31, 2016 USD ($)
United States
Valuation allowance
Deferred tax assets, net of valuation allowance	$ 0

Income Taxes - Operating Loss Carryforwards (Details) $ in Millions	Dec. 31, 2016 USD ($)
Federal and state
Operating loss carryforwards
Net operating loss carryforwards	$ 317.1
Foreign
Operating loss carryforwards
Net operating loss carryforwards	$ 2.8

Income Taxes - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Tax Credit Carryforward [Line Items]
Reversal of tax reserve		$ 903
Tax Reserve Member
Tax Credit Carryforward [Line Items]
Reversal of tax reserve		600
Unrecognized Tax Benefits Reserve Accrued Interest Member
Tax Credit Carryforward [Line Items]
Reversal of tax reserve		$ 300
Forecast
Tax Credit Carryforward [Line Items]
Reversal of tax reserve	$ 500

Income Taxes - Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2016	Dec. 31, 2015
Tax credit carryforwards
Interest and penalty expense recognized related to unrecognized tax benefits	$ 200	$ 200	$ 200
Reconciliation of the beginning and ending balance of unrecognized tax benefits
Balance at beginning of year	7,671	7,960
Increase (decrease) in unrecognized tax benefits as a result of tax positions taken during a prior period	76
Increase (decrease) in unrecognized tax benefits as a result of tax positions taken during a prior period		(78)
Decreases in unrecognized tax benefits related to settlements with tax authorities		(211)
Reductions to unrecognized tax benefits as a result of a lapse of the applicable statute of limitations	(903)
Balance at end of year	6,844	7,671	7,960
Recorded as other long-term liability				$ 1,462	$ 2,142
Recorded as a decrease in deferred tax assets and offsetting valuation allowance				5,382	5,529
Unrecognized tax benefits	$ 7,671	$ 7,960	$ 7,960	6,844	$ 7,671
Research and development and other tax credit carryforwards
Tax credit carryforwards
Tax credit carryforwards				$ 12,800

Quarterly Results of Operations (unaudited) - Results (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Quarterly Results of Operations (unaudited)
Revenue	$ 69,358	$ 65,650	$ 64,451	$ 67,521	$ 70,458	$ 79,317	$ 78,437	$ 73,283	$ 266,980	$ 301,495	$ 203,051
Gross profit	26,947	24,104	25,131	23,415	21,973	29,179	27,174	23,380	99,598	101,706	70,164
Net income	$ 3,965	$ 2,151	$ 2,937	$ 1,948	$ 826	$ 6,101	$ 5,883	$ 1,868	$ 11,001	$ 14,678	$ (11,266)
Net income per basic share (in dollars per share)	$ 0.13	$ 0.07	$ 0.10	$ 0.07	$ 0.03	$ 0.21	$ 0.21	$ 0.07	$ 0.38	$ 0.51	$ (0.40)
Net income per diluted share (in dollars per share)	$ 0.13	$ 0.07	$ 0.10	$ 0.06	$ 0.03	$ 0.20	$ 0.20	$ 0.06	$ 0.36	$ 0.49	$ (0.40)

- Definition

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

+ References + Details

Quarterly Results of Operations (unaudited) - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended				12 Months Ended
	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Quarterly Results of Operations (unaudited)
Inventory reserves	$ 200	$ 800	$ 300	$ 300	$ 600	$ 800
Restructuring charges	$ 300				$ 282	$ 18	$ 2,621
Variable compensation expense		800	$ 2,200
Stock-based compensation acceleration				1,100
Revenue for fully written down inventory		$ 1,500		$ 2,300

Schedule II Valuation and Qualifying Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Allowance for doubtful accounts and returns
Changes in Valuation and Qualifying Accounts
Balance at Beginning of Period		$ 390	$ 404
Charged to Costs and Expenses	$ 106
Deductions	(29)	(390)
Other			(14)
Balance at End of Period	77		390
Inventory reserves
Changes in Valuation and Qualifying Accounts
Balance at Beginning of Period	10,465	23,642	25,091
Charged to Costs and Expenses	1,051	1,185	1,003
Deductions	(2,619)	(14,362)	(2,452)
Balance at End of Period	$ 8,897	$ 10,465	$ 23,642