Mattson Technology (MTSN) 10-K 12 Mar 15 2014 FY Annual report Financial data

Document_and_Entity_Informatio

Document and Entity Information (USD $)	12 Months Ended
In Millions, except Share data, unless otherwise specified	Dec. 31, 2014	Mar. 04, 2015	Jun. 29, 2014
Document and Entity Information
Entity Registrant Name	MATTSON TECHNOLOGY INC
Entity Central Index Key	928421
Current Fiscal Year End Date	-19
Entity Filer Category	Accelerated Filer
Document Type	10-K
Document Period End Date	31-Dec-14
Document Fiscal Year Focus	2014
Document Fiscal Period Focus	FY
Amendment Flag	FALSE
Entity Common Stock, Shares Outstanding		74,647,018
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Public Float			$150.50

Consolidated_Statements_of_Ope

Consolidated Statements of Operations (USD $)	12 Months Ended
In Thousands, except Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Statement [Abstract]
Net revenue	$178,404	$119,434	$126,526
Cost of goods sold	119,587	82,028	81,626
Gross margin	58,817	37,406	44,900
Operating expenses:
Research, development and engineering	19,426	16,915	22,328
Selling, general and administrative	28,866	27,842	36,786
Restructuring and other charges	412	3,662	5,070
Total operating expenses	48,704	48,419	64,184
Income (loss) from operations	10,113	-11,013	-19,284
Interest income (expense), net	-228	-494	133
Other income (expense), net	335	-10	316
Income (loss) before income taxes	10,220	-11,517	-18,835
Provision for (benefit from) income taxes	339	-542	484
Net income (loss)	$9,881	($10,975)	($19,319)
Net income (loss) per share:
Basic (in usd per share)	$0.14	($0.19)	($0.33)
Diluted (in usd per share)	$0.13	($0.19)	($0.33)
Shares used in computing net income (loss) per share:
Basic (in shares)	71,897,000	58,944,000	58,538,000
Diluted (in shares)	73,403,000	58,944,000	58,538,000

Consolidated_Statements_of_Com

Consolidated Statements of Comprehensive Income (Loss) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Statement of Comprehensive Income [Abstract]
Net income (loss)	$9,881	($10,975)	($19,319)
Other comprehensive income (loss), net of tax
Changes in foreign currency translation adjustments	-2,659	-148	512
Change in unrealized investment gain (loss)	0	-29	23
Other comprehensive income (loss)	-2,659	-177	535
Comprehensive income (loss)	$7,222	($11,152)	($18,784)

Consolidated_Balance_Sheets

Consolidated Balance Sheets (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Current assets:
Cash and cash equivalents	$22,760	$14,578
Accounts receivable, net of allowance for doubtful accounts of $669 as of December 31, 2014 and $704 as of December 31, 2013	33,578	26,245
Advance billings	4,653	3,346
Inventories	40,579	34,126
Prepaid expenses and other current assets	9,767	5,267
Total current assets	111,337	83,562
Property and equipment, net	7,534	9,216
Intangibles, net	0	250
Restricted cash	1,993	2,087
Other assets	623	808
Total assets	121,487	95,923
Current liabilities:
Accounts payable	22,434	26,624
Accrued compensation and benefits	4,601	2,713
Deferred revenues, current	9,110	9,107
Revolving credit facility		14,000
Other current liabilities	6,630	4,122
Total current liabilities	42,775	56,566
Deferred revenues, non-current	1,160	1,971
Other liabilities	2,442	3,237
Total liabilities	46,377	61,774
Commitments and contingencies (Note 7)
Stockholders' equity:
Preferred stock, 2,000 shares authorized; none issued and outstanding	0	0
Common stock, par value $0.001, 120,000 shares authorized; 78,267 shares issued and 74,009 shares outstanding as of December 31, 2014; 63,384 shares issued and 59,203 shares outstanding as of December 31, 2013	78	63
Additional paid-in capital	687,871	654,050
Accumulated other comprehensive income	18,171	20,830
Treasury stock, 4,258 shares as of December 31, 2014 and 4,181 shares as of December 31, 2013	-38,083	-37,986
Accumulated deficit	-592,927	-602,808
Total stockholders' equity	75,110	34,149
Total liabilities and stockholders' equity	$121,487	$95,923

Consolidated_Balance_Sheets_Pa

Consolidated Balance Sheets (Parenthetical) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, except Per Share data, unless otherwise specified
Current assets:
Allowance for Doubtful Accounts	$669	$704
Stockholders' equity:
Preferred stock, shares authorized (in shares)	2,000	2,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Common stock, par value per share (in usd per share)	$0.00	$0.00
Common stock, shares authorized (in shares)	120,000	120,000
Common stock, shares issued (in shares)	78,267	63,384
Common stock, shares, outstanding (in shares)	74,009	59,203
Treasury stock, shares (in shares)	4,258	4,181

Consolidated_Statements_of_Sto

Consolidated Statements of Stockholders' Equity (USD $)	Total	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Income	Treasury Stock	Accumulated Deficit
In Thousands, unless otherwise specified
Beginning balance, stockholders' equity at Dec. 31, 2011	$60,145	$63	$650,110	$20,472	($37,986)	($572,514)
Beginnng balance, stockholders' equity (in shares) at Dec. 31, 2011		62,547			-4,181
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	-19,319					-19,319
Other comprehensive loss, net of tax	535			535
Shares issued under employee stock plan, net	238		238
Shares issued under employee stock plan, net (in shares)		256
Shares issued under employee stock purchase plan	128		128
Shares issued under employee stock purchase plan (in shares)		105
Stock-based compensation expense	1,565		1,565
Ending balance, stockholders' equity at Dec. 31, 2012	43,292	63	652,041	21,007	-37,986	-591,833
Ending balance, stockholders' equity (in shares) at Dec. 31, 2012		62,908			-4,181
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	-10,975
Other comprehensive loss, net of tax	-177			-177
Shares issued under employee stock plan, net	445		445
Shares issued under employee stock plan, net (in shares)		413
Shares issued under employee stock purchase plan	131		131
Shares issued under employee stock purchase plan (in shares)		63
Stock-based compensation expense	1,433		1,433
Ending balance, stockholders' equity at Dec. 31, 2013	34,149	63	654,050	20,830	-37,986	-602,808
Ending balance, stockholders' equity (in shares) at Dec. 31, 2013		63,384			-4,181
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	9,881
Other comprehensive loss, net of tax	-2,659			-2,659
Shares issued under employee stock plan, net	307	1	403		-97
Shares issued under employee stock plan, net (in shares)		718			-77
Shares issued under employee stock purchase plan	181		181
Shares issued under employee stock purchase plan (in shares)		83
Shares issued in connection with public offering, net of offering costs	31,725	14	31,711
Shares issued in connection with public offering, net of offering costs (in shares)		14,082
Stock-based compensation expense	1,526		1,526
Ending balance, stockholders' equity at Dec. 31, 2014	$75,110	$78	$687,871	$18,171	($38,083)	($592,927)
Ending balance, stockholders' equity (in shares) at Dec. 31, 2014		78,267			-4,258

Consolidated_Statements_of_Cas

Consolidated Statements of Cash Flows (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Cash flows from operating activities:
Net income (loss)	$9,881	($10,975)	($19,319)
Adjustments to reconcile net income (loss) to net cash used in operating activities:
Depreciation and amortization	2,805	3,971	3,941
Stock-based compensation	1,526	1,433	1,565
Deferred income taxes	145	-450	583
Other non-cash items	59	-156	52
Changes in assets and liabilities:
Accounts receivable	-7,332	-10,702	9,837
Advance billings	-1,307	-1,626	3,351
Inventories	-7,519	-5,317	-2,503
Prepaid expenses and other current assets	-4,878	-536	4,616
Other assets	34	85	252
Accounts payable	-3,979	14,687	-5,312
Accrued compensation and benefits and other current liabilities	4,149	-4,554	-4,553
Deferred revenue	-808	1,830	-6,044
Other liabilities	-434	-526	-2,434
Net cash used in operating activities	-7,658	-12,836	-15,968
Cash flows from investing activities:
(Increase) decrease in restricted cash	69	-202	0
Purchases of property and equipment	-1,395	-1,171	-1,487
Proceeds from sales of property and equipment	12	0	60
Net cash used in investing activities	-1,314	-1,373	-1,427
Cash flows from financing activities:
Proceeds from revolving credit facility, net of borrowing costs	0	28,611	0
Repayment of revolving credit facility	-14,000	-15,000	0
Proceeds from issuance of common stock, net	32,213	576	366
Net cash provided by financing activities	18,213	14,187	366
Effect of exchange rate changes on cash and cash equivalents	-1,059	246	310
Net increase (decrease) in cash and cash equivalents	8,182	224	-16,719
Cash and cash equivalents, beginning of period	14,578	14,354	31,073
Cash and cash equivalents, end of period	22,760	14,578	14,354
Supplemental Disclosure:
Cash paid for interest	210	578	0
Cash paid for income taxes, net of refunds	$107	$422	$794

BASIS_OF_PRESENTATION_AND_SIGN

BASIS OF PRESENTATION AND SIGNIFICANT ACCOUNTING POLICIES	12 Months Ended
	Dec. 31, 2014
Accounting Policies [Abstract]
Basis of Presentation and Significant Accounting Policies	BASIS OF PRESENTATION AND SIGNIFICANT ACCOUNTING POLICIES
	Nature of Operations
	Mattson Technology, Inc. (referred to in this Annual Report on Form 10-K as "Mattson," "we," "us," or "our") was incorporated in California in 1988 and reincorporated in Delaware in 1997. We design, manufacture, market and globally support semiconductor wafer processing equipment used in the fabrication of integrated circuits.
	Basis of Presentation
	The consolidated financial statements include the accounts of Mattson and all our subsidiaries. All inter-company balances and transactions have been eliminated. Our fiscal year ends on December 31. Our interim fiscal quarters are based upon the first quarter ending on the Sunday closest to March 31, with the second and third fiscal quarters each being exactly 13 weeks long.
	Use of Estimates
	The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America ("U.S. GAAP") requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenue and expenses during the reported periods. We evaluate our estimates on an ongoing basis, including those related to the useful lives and fair value of long-lived assets, estimates used to determine facility lease loss liabilities, measurement of warranty obligations, valuation allowances for deferred tax assets, the fair value of stock-based compensation, estimates for allowance for doubtful accounts, and valuation of excess and obsolete inventories. Our estimates and assumptions can be subjective and complex and, consequently, actual results could differ materially from those estimates.
	Reclassifications
	For presentation purposes, certain prior period amounts have been reclassified to conform to the reporting in the current period financial statements. These reclassifications do not affect our net income, cash flows or stockholders' equity.
	Cash and Cash Equivalents
	We consider all highly liquid investments purchased with an original maturity of three months or less to be cash equivalents. Our cash and cash equivalents are carried at fair market value, and consist primarily of cash balances and high-grade money market funds.
	Concentration of Credit Risk
	We maintain our cash and cash equivalents with several financial institutions. Deposits held with banks may exceed the amount of insurance provided by the Federal Deposit Insurance Corporation on such deposits. Generally these deposits may be redeemed upon demand and are maintained with financial institutions with reputable credit.
	We may invest in a variety of financial instruments, such as U.S. treasury bills and notes, commercial paper, money market funds and corporate bonds. We limit the amount of credit exposure to any one financial institution or commercial issuer. Historically, we have not experienced significant losses on these investments.
	Our trade accounts receivable are concentrated with companies in the semiconductor industry and are derived from sales in the U.S., Asia and Europe. As of December 31, 2014, one customer accounted for 74 percent of our total net accounts receivable. As of December 31, 2013, two customers accounted for 61 percent and 23 percent of our total net accounts receivable, respectively.
	Allowance for Doubtful Accounts
	We perform ongoing credit evaluations of our customers and record specific allowances for doubtful accounts when a customer is unable to meet its financial obligations, as in the case of bankruptcy filings or deteriorated financial position. We estimate the allowance for doubtful accounts for all other customers based on factors such as current trends, the length of time the receivables are past due and historical collection experience. We write-off a receivable when all rights, remedies and recourses against the account and its principals are exhausted and record a benefit when previously reserved accounts are collected.
	Fair Value Measurements of Assets and Liabilities
	We measure certain of our assets and liabilities at fair value, using observable market data. The authoritative guidance on fair value measurement defines fair value as an exit price, representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date, and establishes a valuation hierarchy based on the level of independent objective evidence available regarding the value of assets or liabilities. The authoritative guidance also establishes three classes of assets or liabilities: Level 1 consisting of assets and liabilities for which there are quoted prices for identical instruments in active markets; Level 2 consisting of assets and liabilities for which observable inputs other than Level 1 inputs are used such as prices for similar assets or liabilities in active markets or for identical assets or liabilities in less active markets and model-derived valuations for which the variables are derived from or corroborated by observable market data; and Level 3 consisting of assets or liabilities for which there are unobservable inputs to the valuation methodology that are significant to the measurement of the fair value. The category within the valuation hierarchy is based on the lowest level of input that is significant to the fair value measurement.
	Inventories
	Inventories are stated at the lower of cost or market, with cost determined on a first-in, first-out basis, and include material, labor and manufacturing overhead costs. Finished goods are reported as inventories until title transfers to the customer. Under our terms of sale, title generally transfers when we complete physical transfer of the products to the freight carrier, unless other customer practices or terms and conditions prevail. All inter-company profits pertaining to the sales and purchases of inventory among our subsidiaries are eliminated from the consolidated financial statements.
	We assess the valuation of all inventories, including manufacturing raw materials, work-in-process, finished goods and spare parts, at the end of each reporting period. Although we attempt to forecast future inventory demand, given the competitive pressures and cyclical nature of the semiconductor industry, there may be significant unanticipated changes in demand or technological developments that could have a significant impact on the value of our inventories and reported operating results in future periods. The carrying value of our inventory is reduced for estimated excess and obsolescence, which is the difference between its cost and the estimated market value based upon assumptions about future demand. We evaluate the inventory carrying value for potential excess and obsolete inventory exposures by analyzing historical and anticipated demand. In addition, inventories are evaluated for potential obsolescence due to the effect of known and anticipated engineering change orders and new products. If actual demand were to be substantially lower than estimated, additional inventory adjustments for excess or obsolete inventory might be required, which could have a material adverse effect on our business, financial condition and results of operations.
	Inventory includes evaluation tools placed at customer sites as part of our marketing efforts. We typically amortize the cost of the evaluation tools over an estimated period of five years, taking into consideration the estimated cost to refurbish the tools and the estimated net realizable value of the tools. The amortization charges are reported as selling, general and administrative expenses. Amortization expense was $0.4 million, $1.5 million and $1.0 million for the years ended December 31, 2014, 2013 and 2012, respectively.
	Property and Equipment
	Property and equipment are stated at cost. Depreciation is computed using the straight-line method based upon the estimated useful lives of the assets, which range from three to seven years. Leasehold improvements are amortized using the straight-line method over the useful lives or the term of the related lease, whichever is shorter.
	Depreciation expense was $2.2 million, $2.2 million and $2.7 million for the years ended December 31, 2014, 2013 and 2012, respectively. When assets are retired or otherwise disposed of, the assets and the associated accumulated depreciation are removed from the accounts. Repair and maintenance costs are expensed as incurred.
	Long-Lived Assets
	We review our long-lived assets, including property and equipment and intangibles, for impairment whenever events or changes in circumstances indicate that the carrying amounts of these assets may 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 to be recognized is measured based on the amount by which the carrying amount of the asset exceeds its fair value. In 2012, we recorded a $0.2 million impairment charge related to property and equipment that became obsolete as a result of our facility consolidations under our 2011 Restructuring Plan. We had no impairment charges in 2014 and 2013.
	Warranty
	The warranty we offer on equipment sales is generally twelve months, except where previous customer agreements state otherwise. A provision for the estimated cost of warranty, based on historical costs, is recorded as a cost of goods sold when the revenue is recognized for the sale of the related equipment. Our warranty obligations require us to repair or replace defective products or parts during the warranty period at no cost to the customer. The actual system performance and/or field expense profiles may differ from historical experience, and in those cases we adjust our warranty reserves accordingly. Actual warranty reserves and settlements against reserves are highly dependent on our equipment volumes.
	Revenue Recognition
	We derive revenues from the following primary sources - equipment (tool or system) sales, spare part sales and service and maintenance contracts. In accordance with the authoritative guidance on revenue recognition, we recognize revenue on equipment sales as follows: 1) for equipment sales of existing products with new specifications and for sales of new products, revenue is recognized upon customer acceptance; 2) for equipment sales to existing customers with previously demonstrated equipment acceptance, or equipment sales to new customers purchasing equipment with established reliability, we recognize revenue on a multiple element approach in which revenue is recognized upon the delivery of the separate elements to the customer. The revenue we recognize on a delivered element is limited to the amount that is not contingent upon the delivery of additional items such as installation and customer acceptance, and upon transfer of title. For equipment sales we generally recognize revenue for 90 percent of the total invoice amount as revenue upon shipment while 100 percent of the equipment's cost is recognized upon shipment. The remaining portion, generally 10 percent of the total invoice amount, is contingent upon customer acceptance and is recognized once installation services are completed and final customer acceptance of the equipment is received.
	The revenue relating to the undelivered elements is deferred using the relative selling price method, which allocates revenue to each element using the estimated selling prices for the deliverables when vendor-specific objective evidence or third-party evidence is not available. We have determined that the fair value of installation services is substantially less than the 10 percent of the total invoice amount typically assigned to the installation element in our customer agreements. As such, since the amount collectible upon successful installation and customer acceptance exceeds the fair value of the installation services, we defer the amount collectible upon successful installation and customer acceptance.
	From time to time, we allow customers to evaluate equipment, with the customer maintaining the right to return the equipment at its discretion with limited or no penalty. For this type of arrangement, we do not recognize revenue until customer acceptance is received. For spare parts, we recognize revenue upon shipment. For service and maintenance contracts, we recognize revenue on a straight-line basis over the service period of the related contract or as services are performed. In all cases, revenue is only recognized when persuasive evidence of an arrangement exists, delivery has occurred, the price is fixed or determinable and collectability is reasonably assured. Accounts receivable for which revenue has not been recognized are classified as advance billings.
	Research, Development and Engineering Expenses
	Research, development and engineering expenses include the personnel-related costs and outside consulting expenses associated with the research, development and engineering of new products and enhancements to existing products, facility related costs and other corporate allocations. These costs are expensed as incurred.
	Restructuring
	We recognize expenses related to employee termination benefits when the benefit arrangement is communicated to the employee and no significant future services are required of the employee. If an employee is required to render service until a specific termination date, which goes beyond the legal requirement or contractual notice period, in order to receive the termination benefits, the fair value of the associated liability would be recognized ratably over the future service period. Severance costs are determined in accordance with local statutory requirements and our policies.
	We recognize the present value of facility lease termination obligations, net of estimated sublease income and other exit costs, when there are future lease payments with no future economic benefit. Sublease income is estimated based on current market rates for similar properties. If we are unable to sublease the facility on a timely basis or if we are forced to sublease the facility at lower rates due to changes in market conditions, we would adjust the restructuring liability accordingly.
	Stock-Based Compensation
	We measure the fair value of all stock-based awards, including stock options, restricted stock units, and purchase rights under our employee stock purchase plan, on the date of grant and recognize the related stock-based compensation expense on a straight-line basis over the requisite service period, which is generally the vesting period.
	We use the Black-Scholes option-pricing model to determine the fair value of certain of our stock-based awards. The determination of fair value using the Black-Scholes model is affected by our stock price as well as assumptions regarding a number of complex and subjective variables, which includes expected stock price volatility over the term of the awards, actual and projected employee exercise and cancellation behaviors, risk-free interest rates, and expected dividends.
	We estimate the expected life of options based on an analysis of our historical experience of employee exercise and post-vesting termination behavior considered in relation to the contractual life of the option; expected volatility is based on the historical volatility of our common stock; and the risk-free interest rate is equal to the U.S. Treasury rate with a maturity approximating the expected life of the option. We do not currently pay cash dividends on our common stock and do not anticipate doing so in the foreseeable future; accordingly, the expected dividend yield is zero.
	We estimate forfeiture rates on stock-based awards at the time of grant and revise those estimates in subsequent periods if actual forfeitures differ from those estimates. Such forfeiture estimates are based on historical experience. If the assumptions for estimating stock-based compensation expense change in future periods, the amount of future stock-based compensation may differ significantly from the amount that we recorded in the current and prior periods.
	Stock-based compensation expense for the years ended December 31, 2014, 2013 and 2012 was $1.5 million, $1.4 million and $1.6 million, respectively. We did not capitalize any stock-based compensation as inventory in the years ended December 31, 2014, 2013 and 2012 as such amounts were immaterial.
	Foreign Currency
	The functional currencies of our foreign subsidiaries are their local currencies. All assets and liabilities of these foreign operations are translated into the U.S. dollar using exchange rates in effect at the end of the period, and revenues and costs are translated using average exchange rates for the period. Gains or losses from translation of foreign operations where the local currencies are the functional currency are included as a component of accumulated other comprehensive income in the accompanying consolidated balance sheets. Foreign currency transaction gains and losses are recorded in other income (expense), net in the accompanying consolidated statements of operations.
	For the years ended December 31, 2014, 2013 and 2012, we recorded a $0.3 million net foreign currency transaction gain, a $0.6 million net foreign currency transaction loss and a $0.4 million net foreign currency transaction gain, respectively. At December 31, 2014 and 2013, the cumulative translation adjustment was $18.2 million and $20.8 million, respectively.
	Income Taxes
	We provide for income taxes in accordance with the authoritative guidance, which requires a liability-based approach in accounting for income taxes. Deferred income tax assets and liabilities are recorded based on the differences between the financial statement and tax bases of assets and liabilities using enacted tax rates. Valuation allowances are provided against deferred income tax assets, which are not likely to be realized.
	We recognize the tax benefit from an uncertain tax position only if it is more likely than not that the tax position will be sustained on examination by taxing authorities, based on the technical merits of the position. The tax benefits recognized in the financial statements from such a position are measured based on the largest benefit that has a greater than fifty percent likelihood of being realized upon ultimate resolution.
	Recent Accounting Pronouncements
	In May 2014, the FASB issued ASU 2014-09, Revenue from Contracts with Customers. The FASB issued ASU No. 2014-09 to clarify the principles for recognizing revenue and to develop a common revenue standard for GAAP and International Financial Reporting Standards. The standard outlines a single comprehensive model for entities to use in accounting for revenue arising from contracts with customers and supersedes the most current revenue recognition guidance. This guidance is effective for fiscal years and interim periods within those years beginning after December 15, 2016, which is effective for us as of the first quarter of 2017. We are currently evaluating the impact that the implementation of this standard will have on our financial statements.

BALANCE_SHEET_DETAILS

BALANCE SHEET DETAILS	12 Months Ended
	Dec. 31, 2014
Balance Sheet Related Disclosures [Abstract]
Balance Sheet Details	BALANCE SHEET DETAILS
	At December 31, 2014 and 2013, we had restricted cash of $2.0 million and $2.1 million, respectively, which is primarily related to secured standby letters of credit for our long-term leases. Accordingly, such amounts are classified as long term in the accompanying consolidated balance sheets. See Note 7. Commitments and Contingencies for additional details related to the standby letters of credit.
	Components of inventories as of December 31 are shown below (in thousands):
		2014			2013
	Inventories:
	Purchased parts and raw materials	$	28,143		$	26,842
	Work-in-process	10,832			4,260
	Finished goods	1,604			3,024
		$	40,579		$	34,126
	Components of prepaid expenses and other current assets as of December 31 are shown below (in thousands):
		2014			2013
	Prepaid expenses and other current assets:
	Value-added tax	$	4,184		$	2,134
	Other current assets	5,583			3,133
		$	9,767		$	5,267
	Components of property and equipment as of December 31 are shown below (in thousands):
		2014			2013
	Property and equipment, net:
	Machinery and equipment	$	40,777		$	42,329
	Furniture and fixtures	9,079			9,908
	Leasehold improvements	17,646			18,626
		67,502			70,863
	Less: accumulated depreciation	(59,968		)	(61,647		)
		$	7,534		$	9,216
	Components of other current liabilities as of December 31 are shown below (in thousands):
		2014			2013
	Other current liabilities:
	Warranty	$	2,803		$	1,786
	Value-added tax	1,547			358
	Accrued restructuring charge - current	366			812
	Other	1,914			1,166
		$	6,630		$	4,122

FAIR_VALUE_MEASUREMENT

FAIR VALUE MEASUREMENT	12 Months Ended
	Dec. 31, 2014
Fair Value Disclosures [Abstract]
Fair Value Measurement	FAIR VALUE MEASUREMENT
	Our money market funds are classified within Level 1 of the fair value hierarchy, as these instruments are valued using quoted market prices. Specifically, we value our investments in money market securities and certificates of deposit on quoted market prices in active markets. As of December 31, 2014 and 2013, we had no assets or liabilities classified within Level 2 or Level 3 and there were no transfers of instruments between Level 1, Level 2 and Level 3 regarding fair value measurement.
	Cash and cash equivalents and restricted cash are carried at fair value. Accounts receivable and accounts payable are valued at their carrying amounts, which approximate fair value due to their short-term nature. The estimated fair value of any amounts outstanding under our revolving credit facility approximates the carrying value because the interest rate on such debt adjusts to market rates on a periodic basis.
	Assets and Liabilities Measured at Fair Value on a Recurring Basis
	Assets and liabilities measured at fair value on a recurring basis are shown in the table below by their corresponding balance sheet captions and consisted of the following types of instruments as of December 31 (in thousands):
		2014				2013
		Fair Value Measurements at				Fair Value Measurements at
		Reporting Date Using				Reporting Date Using
		(Level 1)		Total		(Level 1)		Total
	Assets measured at fair value:
	Cash and cash equivalents:
	Money market funds	$	7,007	$	7,007	$	5	$	5
	Restricted cash:
	Money market funds	1,806		1,806		1,875		1,875
	Total assets measured at fair value	$	8,813	$	8,813	$	1,880	$	1,880

INTANGIBLE_ASSETS

INTANGIBLE ASSETS	12 Months Ended
	Dec. 31, 2014
Intangible Assets, Net (Excluding Goodwill) [Abstract]
Intangible Assets	INTANGIBLE ASSETS
	Identified intangible assets consisted of the following as of December 31 (in thousands):
		2014			2013
	Developed technology	$	1,250		$	1,250
	Accumulated amortization	(1,250		)	(1,000		)
		$	—		$	250
	Amortization expense for intangibles was $0.3 million in each of the years ended December 31, 2014, 2013 and 2012, and was included as part of research, development and engineering expense.

REVOLVING_CREDIT_FACLITY_Notes

REVOLVING CREDIT FACLITY (Notes)	12 Months Ended
	Dec. 31, 2014
Revolving Credit Facility [Abstract]
Revolving Credit Facility	REVOLVING CREDIT FACILITY
	On April 12, 2013, we entered into a three-year $25.0 million senior secured revolving credit facility ("credit facility") with Silicon Valley Bank. On October 21, 2014, we entered into Amendment Agreement No. 4 with Silicon Valley Bank ("Amendment"), which extends the term of our credit facility to October 12, 2017. In the absence of an event of default, any amounts outstanding under the credit facility may be repaid and re-borrowed anytime until the termination date. This Amendment also allows us to make a one-time request to increase the existing credit facility up to an additional $25.0 million.
	Under the Amendment, the advances available to us under the borrowing base formula increased to 85 percent of eligible accounts receivable and advance billings and 50 percent of eligible inventory.
	The Amendment also retroactively lowered our required minimum consolidated earnings before interest, tax, depreciation, and amortization ("EBITDA") from $6.0 million to $2.0 million for the two consecutive quarters immediately prior to the end of the reporting period, commencing with the fiscal quarter ended September 28, 2014; established a minimum quick ratio requirement equal to or greater than 1.00 through March 29, 2015 and 1.25 thereafter; and removed certain financial covenants when our "Available Funds," as defined in the Amendment to be cash, cash equivalents and availability under the credit agreement, are equal to or greater than $30.0 million as of the last day of such fiscal quarter.
	At our option, the borrowings under the credit facility can bear interest at an Alternate Base Rate (“ABR”) or Eurodollar Rate. ABR loans bear interest at a per annum rate equal to the greater of the Federal Funds Effective Rate plus 0.5 percent or the prime rate, plus an applicable margin. Eurodollar loans bear interest at a margin over British Bankers' Association LIBOR Rate divided by 1 minus Eurocurrency Reserve Requirements. The Amendment lowered the applicable margin, as defined in the Amendment, with respect to our interest rate on outstanding borrowings to zero percent for ABR loans and 2.75 percent per annum for Eurodollar loans. As of December 31, 2014, the effective interest rate on any outstanding borrowings would have been 3.25 percent per annum, which is variable and represents the greater of the Federal Funds Effective Rate plus 0.50 percent or the prime rate. If an event of default occurs under the credit facility, the interest rate will increase by 2.0 percent per annum.
	The obligations under the credit facility are guaranteed by Mattson International, Inc., our wholly-owned subsidiary (together with Mattson, collectively referred to as the “Loan Parties”), and are secured by substantially all of the assets of the Loan Parties, including a pledge of the capital stock holdings of the Loan Parties in certain of our direct subsidiaries.
	The credit facility contains customary affirmative covenants and negative covenants including financial covenants requiring us and our subsidiaries to maintain a minimum level of consolidated EBITDA, for two consecutive quarters, and a minimum quick ratio, as well as restrictions on liens, investments, indebtedness, fundamental changes, sale leaseback transactions, swap agreements, accounting changes, dispositions of property, making certain restricted payments (including restrictions on dividends and stock repurchases), entering into new lines of business, and transactions with affiliates. Additionally, our credit facility restricts our ability to pay dividends, subject to certain limited exceptions.
	The obligations under the credit facility may be accelerated upon the occurrence of an event of default under the credit facility, which includes customary events of default, including payment defaults, defaults in the performance of affirmative and negative covenants, the material inaccuracy of representations or warranties, bankruptcy and insolvency related defaults, defaults relating to matters such as ERISA, judgments, and a change of control. Due to the potential for acceleration of obligations under the credit facility upon the occurrence of certain events, some of which are outside our control, borrowings under the credit facility are classified within current liabilities in the consolidated balance sheets.
	We incurred $0.4 million in debt issuance costs in connection with the credit facility and a commitment fee of $62,500 related to the extension of the term of the facility from April 12, 2016 to October 12, 2017. These costs are being amortized over the term of the credit facility. In addition, we pay monthly commitment fees equal to 0.375 percent per annum on the unused portion of the credit facility.
	At December 31, 2014 and 2013, we had zero and $14.0 million, respectively, outstanding under the credit facility.

RESTRUCTURING_AND_OTHER_CHARGE

RESTRUCTURING AND OTHER CHARGES	12 Months Ended
	Dec. 31, 2014
Restructuring Charges [Abstract]
Restructuring and Other Charges	RESTRUCTURING AND OTHER CHARGES
	In December 2011, our management approved and initiated a cost reduction plan ("2011 Restructuring Plan") as part of a broad-based cost reduction initiative. The 2011 Restructuring Plan included the consolidation of our manufacturing and research and development facilities, including contract termination costs related to two vacant facilities; moving a portion of our outsourced spare parts logistics operations in-house; and workforce reductions.
	The following table summarizes changes in our restructuring accrual for the years ended December 31, 2014, 2013 and 2012 (in thousands):
		Employee			Contract			Other			Total
		Severance			Termination			Costs
		Costs			Costs
	Balance at December 31, 2011	$	82		$	2,661		$	—		$	2,743
	Restructuring charges (1)	4,011			355			704			5,070
	Payments	(2,190		)	(1,420		)	(474		)	(4,084		)
	Write-off of long-term assets (1)	—			—			(230		)	(230		)
	Reserve adjustments	102			4			—			106
	Balance at December 31, 2012	2,005			1,600			—			3,605
	Restructuring charges	2,413			825			424			3,662
	Payments	(4,406		)	(1,322		)	(399		)	(6,127		)
	Reserve adjustments	(12		)	—			(25		)	(37		)
	Balance at December 31, 2013	—			1,103			—			1,103
	Restructuring charges	506			(94		)	—			412
	Payments	(358		)	(739		)	—			(1,097		)
	Reserve adjustments	(20		)	(32		)	—			(52		)
	Balance at December 31, 2014	$	128		$	238		$	—		$	366
	(1) During 2012, we recorded a $0.2 million charge related to impairment of property and equipment resulting from the transfer of our research, development and prototype production of the Millios system to our facility in Dornstadt, Germany and the consolidation of global manufacturing in our facility in Fremont, California.
	For the year ended December 31, 2014, we recorded restructuring charges of $0.4 million, which included $0.5 million related to workforce reductions and a $0.1 million benefit from a revised estimate of our future rent obligations for one of our vacant facilities. We paid $0.4 million in employee severance and $0.7 million in contract termination costs during 2014.
	For the year ended December 31, 2013, we recorded restructuring charges of $3.7 million, which included $2.8 million in employee severance and other costs relating primarily to recruiting costs for our new chief executive officer and severance expense for our former chief executive officer totaling approximately $0.6 million, and other workforce reductions. We also incurred $0.8 million in contract termination costs related to future rent obligations, net of sublease income, associated with two vacated leased facilities. We paid $4.8 million in employee severance and other costs and $1.3 million in contract termination costs during 2013.
	For the year ended December 31, 2012, we recorded restructuring charges of $5.1 million, which included $4.7 million in employee severance and other costs and $0.4 million in contract termination costs. We paid $2.7 million in employee severance and other costs and $1.4 million contract termination costs during 2012.
	As of December 31, 2014, we had $0.4 million in accrued restructuring charges, which was classified within other current liabilities in our consolidated balance sheet. As of December 31, 2013, we had $1.1 million in accrued restructuring charges, of which $0.8 million was classified within other current liabilities and $0.3 million was classified within other liabilities in the consolidated balance sheet.
	We plan to make payments related to the remaining accrued restructuring charges throughout 2015.

COMMITMENTS_AND_CONTINGENCIES

COMMITMENTS AND CONTINGENCIES	12 Months Ended
	Dec. 31, 2014
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	COMMITMENTS AND CONTINGENCIES
	Warranty
	The warranty offered by us on our system sales is generally twelve months, except where previous customer agreements state otherwise, and excludes certain consumable maintenance items. A provision for the estimated cost of warranty, based on historical costs, is recorded as cost of sales when the revenue is recognized. Our warranty obligations require us to repair or replace defective products or parts during the warranty period at no cost to the customer. The actual system performance and/or field warranty expense profiles may differ from historical experience, and in those cases, we adjust our warranty accruals accordingly.
	The following table summarizes changes in our product warranty accrual for the years ended December 31 (in thousands):
		2014			2013			2012
	Beginning balance	$	1,786		$	1,691		$	3,419
	Warranties issued in the period	2,783			2,031			2,242
	Costs to service warranties	(3,059		)	(1,981		)	(4,286		)
	Warranty accrual adjustments	1,293			45			316
	Ending balance	$	2,803		$	1,786		$	1,691
	Operating Leases
	We hold various operating leases related to our worldwide facilities and equipment. Our minimum annual lease commitments with respect to our operating leases were as follows as of December 31, 2014 (in thousands):
	Year Ending December 31,	Minimum Future Lease Payments			Sublease Rental Income			Minimum Future Lease Payments
	2015	$	3,356		$	(179	)	$	3,177
	2016	2,774			—			2,774
	2017	3,054			—			3,054
	2018	717			—			717
	2019	716			—			716
	Thereafter	716			—			716
		$	11,333		$	(179	)	$	11,154
	Rent expense was $4.1 million, $3.9 million and $4.3 million in 2014, 2013 and 2012, respectively. We recorded sublease income related to our Exton, Pennsylvania and Vancouver, Canada facilities of $0.2 million, $0.4 million and $0.4 million for the years ended December 31, 2014, 2013 and 2012, respectively.
	In 2005, we entered into a lease agreement for the building which serves as our corporate headquarters in Fremont, California. The lease is for a period of ten years, which commenced on May 31, 2007, and has an initial annual base rent cost of approximately $1.4 million, with annual increases of approximately 3.5 percent. We also are responsible for an additional minimum lease payment at the end of the lease term of approximately $1.5 million, subject to adjustment, under a restoration cost obligation provision, which is being recognized on a straight-line basis over the lease term. To secure this obligation, we provided the landlord a standby letter of credit of $1.5 million.
	Guarantees
	In the ordinary course of business, our bank provides standby letters of credit or other guarantee instruments on our behalf to certain parties as required. The standby letters of credit are primarily secured by money market accounts, which are classified as restricted cash in the accompanying consolidated balance sheets. We have never recorded any liability in connection with these guarantee arrangements beyond what is required to appropriately account for the underlying transaction being guaranteed. We do not believe, based on historical experience and information currently available, that it is probable that any amounts will be required to be paid under such guarantee arrangements. As of December 31, 2014, the maximum potential amount that we could be required to pay under our outstanding standby letters of credit was $1.7 million, which was secured by $2.0 million in money market fund accounts and recorded as restricted cash.
	In connection with our acquisition of Vortek Industries, Ltd. ("Vortek") in 2004, we became party to an agreement between Vortek and the Canadian Minister of Industries (the "Minister") relating to an investment in Vortek by Technology Partnerships Canada. Under the agreement, as amended, we, or Vortek (renamed Mattson Technology, Canada, Inc. ("MTC")) agreed to various terms, including (i) payment by us of a royalty to the Minister of 1.4 percent of net revenues from certain Flash RTP products, up to a total of C$14.3 million (approximately $12.3 million based on the applicable exchange rate as of December 31, 2014), (ii) MTC maintaining a specified average workforce of employees in Canada, making certain investments and complying with certain manufacturing, each, through October 27, 2009, and (iii) certain other covenants concerning protection of intellectual property rights. Under the provisions of this agreement, if MTC is dissolved, files for bankruptcy or we, or MTC, do not materially satisfy the obligations pursuant to any material terms or conditions, the Minister could demand payment of liquidated damages in the amount of C$14.3 million less any royalties paid to the Minister. As of October 27, 2009, we were no longer subject to covenant (ii), as discussed above but are still subject to the remaining terms and conditions until the earlier of payment of royalty of C$14.3 million (approximately $12.3 million based on the applicable exchange rate as of December 31, 2014) or through December 31, 2020. We have recorded approximately C$0.4 million in cumulative royalty charges to date. The movement of our Canadian operations to Germany did not result in the dissolution of MTC.
	We are a party to a variety of agreements, pursuant to which we may be obligated to indemnify other parties with respect to certain matters. Typically, these obligations arise in the context of contracts under which we may agree to hold other parties harmless against losses arising from a breach of representations or with respect to certain intellectual property, operations or tax-related matters. Our obligations under these agreements may be limited in terms of time and/or amount, and in some instances, we may have defenses to asserted claims and/or recourse against third parties for payments made. It is not possible to predict the maximum potential amount of future payments under these or similar agreements due to the conditional nature of our obligations and the unique facts and circumstances involved in each particular agreement. Historically, our payments under these agreements have not had a material effect on our financial position, results of operations or cash flows. We believe if we were to incur a loss in any of these matters, such loss would not have a material effect on our financial position, results of operations or cash flows.
	We indemnify our directors and certain employees as permitted by law, and have entered into indemnification agreements with our directors and certain senior officers. We have not recorded a liability associated with these indemnification agreements, as we historically have not incurred any material costs associated with such indemnification agreements. Costs associated with such indemnification agreements may be mitigated, in whole or only in part, by insurance coverage that we maintain.
	Government Agencies
	As an exporter, we must comply with various laws and regulations relating to the export of products and technology from the U.S. and other countries having jurisdiction over our operations. In the U.S. these laws include the International Traffic in Arms Regulations ("ITAR") administered by the State Department's Directorate of Defense Trade Controls, the Export Administration Regulations ("EAR") administered by the Bureau of Industry and Security ("BIS"), and trade sanctions against embargoed countries and destinations administered by the U.S. Department of Treasury, Office of Foreign Assets Control ("OFAC"). The EAR governs products, parts, technology and software which present military or weapons proliferation concerns, so-called "dual use" items, and ITAR governs military items listed on the United States Munitions List. Prior to shipping certain items, we must obtain an export license or verify that license exemptions are available. In addition, we must comply with certain requirements related to documentation, record keeping, plant visits and hiring of foreign nationals.
	As previously reported, in 2008 we self-disclosed to BIS certain inadvertent EAR violations. In April 2012, we entered into a settlement agreement with BIS that resolved in full all matters contained in our voluntary self-disclosure. Under the settlement, we agreed to a civil penalty of $0.9 million of which we paid $0.3 million in May 2012. Payment of the remaining $0.6 million was suspended for a one-year period ended April 30, 2013 and was waived given there were no violations during that period.
	Litigation
	In the ordinary course of business, we are subject to claims and litigation, including claims that we infringe third party patents, trademarks and other intellectual property rights. Although we believe that it is unlikely that any current claims or actions will have a material adverse impact on our operating results or our financial position, given the uncertainty of litigation, we cannot be certain of this. The defense of claims or actions against us, even if without merit, could result in the expenditure of significant financial and managerial resources.
	We record a legal liability when we believe it is both probable that a liability has been incurred, and the amount can be reasonably estimated. We monitor developments in our legal matters that could affect the estimate we have previously accrued. Significant judgment is required to determine both probability and the estimated amount.

STOCKHOLDERS_EQUITY

STOCKHOLDERS' EQUITY	12 Months Ended
	Dec. 31, 2014
Equity [Abstract]
Stockholders' Equity	STOCKHOLDERS' EQUITY
	Common Stock
	In February 2014, we completed a registered public offering of 14.1 million newly issued shares of our common stock. The common stock was issued at a price to the public of $2.45 per share. We received net proceeds of approximately $31.7 million from the offering after deducting approximately $2.8 million in underwriting discounts and offering expenses.
	Treasury Stock
	We report common stock repurchased as treasury stock in the accompanying consolidated balance sheets. Treasury stock as of December 31, 2014 and 2013 was 4.3 million and 4.2 million shares, respectively, at a total purchase price of $38.1 million and $38.0 million, respectively.
	Accumulated Other Comprehensive Income
	The activity in accumulated other comprehensive income ("AOCI") for the years ended December 31 is as follows (thousands):
		2014			2013			2012
	Foreign currency translation adjustments:
	Balance at beginning of period	$	20,830		$	20,978		$	20,466
	Reclassification to earnings, net of tax impact	—			(488		)	—
	Change in currency translation adjustment, net of tax	(2,659		)	340			512
	Balance at end of period	18,171			20,830			20,978
	Unrealized investment gain:
	Balance at beginning of period	—			29			6
	Reclassification to earnings, net of tax	—			(29		)	(6		)
	Changes in unrealized investment gain, net of tax	—			—			29
	Balance at end of period	—			—			29
	Accumulated other comprehensive income end of period	$	18,171		$	20,830		$	21,007
	During the fourth quarter of fiscal year 2013, we recorded $0.5 million in other income (expense), net within our consolidated statement of operations related to the liquidation of our Japan and Italy subsidiaries and the release of the corresponding cumulative translation adjustment.
	During the years ended December 31, 2014, 2013 and 2012, any realized gains or losses on our investments were reclassified from AOCI to other income (expense), net in our consolidated statements of operations.
	Stockholder Rights Plan
	On July 28, 2005, we adopted a Stockholder Rights Plan ("the Rights Plan"), under which stockholders of record at the close of business on August 15, 2005 received one share purchase right ("Right") for each share of our common stock held on that date. The Rights, which currently trade with our common stock and represent the right to purchase one one thousandth of a share of preferred stock at $55 per share, become exercisable when a person or group acquires 15 percent or more of our common stock ("the acquiror") without prior approval of our Board of Directors. In that event, the Rights would permit our stockholders, other than the acquiror, to purchase shares of our common stock having a market value of twice the exercise price of the Rights, in lieu of the preferred stock. Also, under the Rights Plan, (i) prior to a person or group acquiring 15 percent of our common stock, we can redeem the Rights for $0.001 each; (ii) we can issue one Right for each share of common stock that becomes outstanding after the record date and before the acquisition of 15 percent of our common stock by an acquiror; (iii) when the Rights become exercisable, our Board of Directors may authorize the issuance of one share of our common stock in exchange for each Right that is then exercisable; and (iv) in the event of certain business combinations, the Rights permit the purchase of the common stock of an acquiror at a 50 percent discount. The Rights expire on July 27, 2015. As of December 31, 2014, we had approximately 50 million share purchase rights outstanding.

EMPLOYEE_STOCK_PLANS

EMPLOYEE STOCK PLANS	12 Months Ended
	Dec. 31, 2014
Employee Service Share-based Compensation, Aggregate Disclosures [Abstract]
Employee Stock Plans	EMPLOYEE STOCK PLANS
	In May 2012, our shareholders approved our 2012 Equity Incentive Plan (the "2012 Plan"), which amended and restated the 2005 Equity Incentive Plan to increase our common stock available for grant under the plan by an additional 2.5 million shares, bringing the total shares reserved for issuance to approximately 17.0 million shares of common stock.
	As of December 31, 2014, we had approximately 3.3 million shares available for future grant under our 2012 Plan.
	Stock Options
	Options to purchase common stock granted under the 2012 Plan generally have terms not exceeding seven years. Options to purchase stock under our equity incentive plans are granted at exercise prices that are at least 100 percent of the fair market value of our common stock on the date of grant. Generally, 25 percent of the options vest on the first anniversary of the vesting commencement date, and the remaining options vest 1/36 per month for the next 36 months thereafter. In December 2013, our Board of Directors approved the adoption of monthly vesting of stock options for employees with a minimum of one year of service.
	We granted 0.7 million, 1.6 million and 3.1 million stock options during 2014, 2013 and 2012, respectively, with an estimated total grant date fair value of $0.9 million, $1.4 million and $2.9 million, respectively. We settle employee stock option exercises with newly issued common shares.
	The following table summarizes the stock option activity under all of our equity incentive plans for the years ended December 31, 2014 and 2013:
		Number of Shares		Weighted-			Weighted Average Remaining Contractual Life		Aggregate Intrinsic Value
				Average
				Exercise
				Price Per Share
		(thousands)					(years)		(thousands)
	Outstanding at December 31, 2012	7,614		$	3.34
	Granted	1,579		1.4
	Exercised	(405	)	1.1
	Forfeited or expired	(3,795	)	4.29
	Outstanding at December 31, 2013	4,993		$	2.18		4.9		$	5,281
	Granted	746		2.42
	Exercised	(486	)	1.03
	Forfeited or expired	(333	)	7.01
	Outstanding at December 31, 2014	4,920		$	2.01		4.2		$	7,513
	Vested and expected to vest at December 31, 2014	4,586		$	2.01		4.1		$	7,040
	Exercisable at December 31, 2014	3,175		$	2.06		3.6		$	4,907
	The aggregate intrinsic value represents the pre-tax differences between the exercise price of stock options and the quoted market price of our stock on December 31, 2014 for all in-the-money stock options.
	The following table provides supplemental information pertaining to our stock options for the years ended December 31 (in thousands, except weighted-average fair values):
		2014			2013			2012
	Weighted-average fair value of options granted	$	1.24		$	0.87		$	0.95
	Intrinsic value of options exercised	$	685		$	386		$	211
	Cash received from options exercised	$	502		$	445		$	238
	Restricted Stock Units
	The 2012 Plan provides for grants of time-based and performance-based restricted stock units ("RSUs"). As of December 31, 2014, we only had time-based RSUs outstanding.
	Time-Based Restricted Stock Units
	Historically, 25 percent of the time-based RSUs vest on each anniversary of the vesting commencement date or date of grant. In December 2013, our Board of Directors approved a quarterly vesting schedule for RSUs. On occasion, we grant time-based RSUs for varying purposes with different vesting schedules. Time-based RSUs granted under the 2012 Plan are counted against the total number of shares of common stock available for grant at a ratio of 1.75 shares of common stock for every one share of common stock subject thereto.
	Stock-based compensation expense on time-based RSUs is determined based on the fair value of our common stock on the date of grant of the RSU and recognized over the vesting period.
	Performance-Based Restricted Stock Units
	The vesting of performance-based RSUs is contingent on our achievement of certain predetermined financial goals and in some cases, the achievement of certain market performance measures. The amount of stock-based compensation expense recognized in any one period can vary based on the achievement or anticipated achievement of these specific performance goals. If a performance goal is not met or is not expected to be met, no compensation cost would be recognized on the underlying RSUs, and any previously recognized compensation expense on those RSUs would be reversed.
	The following table summarizes RSU activity under all of our equity incentive plans for the years ended December 31, 2014 and 2013:
		Number of Shares		Weighted Average Grant Date Fair Value
		(thousands)
	Outstanding at December 31, 2012	32		$	1.28
	Granted	416		$	1.46
	Released	(8	)	$	1.16
	Forfeited or Expired	(11	)	$	1.6
	Outstanding at December 31, 2013	429		$	1.45
	Granted	697		$	2.42
	Released	(232	)	$	1.99
	Forfeited or Expired	(17	)	$	2.49
	Outstanding at December 31, 2014	877		$	2.06
	Employee Stock Purchase Plan
	Our 1994 Employee Stock Purchase Plan (“1994 Plan”) was originally adopted by the Board of Directors and approved by the stockholders in 1994. In May 2014, the Board of Directors amended and restated the 1994 Plan, which was then approved by the stockholders, extending the term of the 1994 Plan by an additional ten years, with an expiration date of May 19, 2024.
	Our 1994 Plan is a non-compensatory employee stock purchase plan ("ESPP"), which allows each eligible employee to withhold up to 15 percent of gross compensation over semi-annual six month ESPP periods to purchase shares of our common stock, limited to 2,000 shares per ESPP period through December 2013, and 4,000 shares per ESPP period thereafter. Under the ESPP, employees purchase stock at a price equal to 90 percent of the fair market value (generally the closing price of our common stock) on the last trading day prior to the end of the six month ESPP offering period.
	We reserved 6.2 million shares of common stock for issuance under the ESPP, of which 2.5 million shares were available for issuance as of December 31, 2014. We issued approximately 0.1 million shares under the ESPP in each of the years ended December 31, 2014, 2013 and 2012, with average purchase prices of $2.17, $2.09 and $1.23, respectively.
	Employee Savings Plan
	We have an employee retirement and savings plan (the "ESP"), which qualifies under section 401(k) of the Internal Revenue Code. All full-time employees of eligible age (over 21 years old) can participate in the ESP and can contribute up to an amount allowed by the applicable Internal Revenue Service guidelines. At our discretion, we can make matching contributions to the ESP equal to a percentage of the participants' contributions. For the years ended December 31, 2014, 2013 and 2012, we recorded 401(k) match contributions in the amount of $0.2 million, $0.1 million and $0.2 million, respectively.

STOCKBASED_COMPENSATION

STOCK-BASED COMPENSATION	12 Months Ended
	Dec. 31, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock-Based Compensation	STOCK-BASED COMPENSATION
	We account for stock-based compensation in accordance with the applicable authoritative guidance, which requires the measurement of stock-based compensation on the date of grant based on the fair value of the award, and the recognition of the expense over the requisite service period for the employee. Compensation related to RSUs is the intrinsic value on the date of grant, which is the closing price of our common stock less the employee exercise price, if any. Compensation related to stock options is determined using a stock option valuation model.
	Valuation Assumptions
	We use the Black-Scholes valuation model to determine the fair value of stock options. The Black-Scholes model requires the input of highly subjective assumptions, which are summarized in the table below for the years ended December 31:
		2014		2013	2012
	Expected dividend yield	—		—	—
	Expected stock price volatility	67%		83%	82%
	Risk-free interest rate	1.30%		0.90%	0.50%
	Expected life of options in years	4		4.4	1.5 - 5
	We estimate the expected life of options based on an analysis of our historical experience of employee exercise and post-vesting termination behavior considered in relation to the contractual life of the option. Expected volatility is based on the historical volatility of our common stock. The risk-free interest rate is the rate on a U.S. Treasury Bill, with a maturity approximating the expected life of the option. We do not currently pay cash dividends on our common stock and do not anticipate doing so in the foreseeable future. Accordingly, the expected dividend yield is zero.
	Our stock-based compensation for the years ended December 31 was as follows (in thousands):
		2014			2013		2012
	Stock-based compensation by type of award:
	Stock options	$	994		$	1,289	$	1,527
	Restricted stock units	484			124		18
	Employee stock purchase plan	48			20		20
		$	1,526		$	1,433	$	1,565
	Stock-based compensation by category of expense:
	Cost of goods sold	$	40		$	52	$	68
	Research, development and engineering	181			254		308
	Selling, general and administrative	1,305			1,127		1,189
		$	1,526		$	1,433	$	1,565
	We did not capitalize any stock-based compensation as inventory in the years ended December 31, 2014, 2013 and 2012, as such amounts were immaterial. As of December 31, 2014, we had $1.4 million in unrecognized stock-based compensation expense, net of estimated forfeitures, related to stock options that will be recognized over a weighted-average period of 2.4 years. As of December 31, 2014, we had $1.2 million in unrecognized stock-based compensation expense, net of estimated forfeitures, related to unvested RSUs that will be recognized over a weighted-average period of 2.8 years.

GEOGRAPHIC_AND_CUSTOMER_CONCEN

GEOGRAPHIC AND CUSTOMER CONCENTRATION INFORMATION	12 Months Ended
	Dec. 31, 2014
Geographic and Customer Concentration Information [Abstract]
Geographic and Customer Concentration Information	GEOGRAPHIC AND CUSTOMER CONCENTRATION INFORMATION
	The authoritative guidance on segment reporting and disclosure defines an operating segment as a component of an enterprise for which separate financial information is available that is evaluated regularly by the chief operating decision maker in deciding how to allocate resources and in assessing performance. For the purposes of evaluating our reportable segments, our Chief Executive Officer is the chief operating decision maker.
	We have one operating segment in which we design, manufacture and market advanced fabrication equipment for the semiconductor manufacturing industry. As our business is completely focused on one industry segment, the design, manufacture and marketing of advanced fabrication equipment to the semiconductor manufacturing industry, management believes that we have one reportable segment. Our net sales and profits are generated from the sales of systems and services in this one segment.
	The following table summarizes net revenue by geographic areas based on the installation locations of the systems and the location of services rendered (in thousands, except percentages):
		For the Years Ended December 31,
		2014				2013			2012
		Amount		Percent		Amount		Percent	Amount		Percent
	Net revenue:
	United States	$	25,716	14		$	12,350	10	$	17,476	14
	Korea	87,585		49		22,173		19	47,611		38
	Taiwan	32,304		18		50,782		43	28,577		23
	China	17,369		10		20,250		17	8,562		7
	Other Asia	6,869		4		8,740		7	13,615		10
	Europe and others	8,561		5		5,139		4	10,685		8
		$	178,404	100		$	119,434	100	$	126,526	100
	In 2014, one customer accounted for 10 percent or more of our total net revenues. Sales to this customer represented approximately 61 percent of our total net revenues. In 2013, two customers accounted for 10 percent or more of our total net revenues. Sales to these customers represented 35 percent and 33 percent of our total net revenues, respectively. In 2012, two customers accounted for 10 percent or more of our total net revenues. Sales to these customers represented approximately 41 percent and 12 percent of our total net revenues, respectively.
	As of December 31, 2014, one customer accounted for 10 percent or more of our total net accounts receivable, representing approximately 74 percent of our total net accounts receivable. As of December 31, 2013, two customers accounted for 10 percent or more of our net accounts receivable, representing approximately 61 percent and 23 percent of our total net accounts receivable, respectively.
	Geographical information relating to our property and equipment, net, as of December 31 was as follows (in thousands):
		2014		2013
	Property and equipment, net:
	United States	$	4,140	$	4,949
	Germany	3,185		4,129
	Others	209		138
		$	7,534	$	9,216

INCOME_TAXES

INCOME TAXES	12 Months Ended
	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Income Taxes
		INCOME TAXES
	The components of income (loss) before income taxes for the years ended December 31 are as follows (in thousands):
		2014			2013			2012
	Domestic income (loss)	$	7,248		$	(21,743	)	$	(20,522	)
	Foreign income	2,972			10,226			1,687
	Income (loss) before income taxes	$	10,220		$	(11,517	)	$	(18,835	)
	The provision for (benefit from) income taxes for the years ended December 31 consists of the following (in thousands):
		2014			2013			2012
	Current:
	Federal	$	—		$	(466	)	$	(251	)
	State	28			52			3
	Foreign	160			(125		)	254
	Total current	188			(539		)	6
	Deferred:
	Federal	—			—			—
	State	—			—			—
	Foreign	151			(3		)	478
	Total deferred	151			(3		)	478
	Provisions for (benefit from) income taxes	$	339		$	(542	)	$	484
	The provision for (benefit from) income taxes reconciles to the amount computed by multiplying income (loss) before income taxes by the U.S. statutory rate of 35 percent as follows (in thousands):
		Years Ended December 31,
		2014			2013			2012
	Benefits at statutory rate	$	3,577		$	(4,031	)	$	(6,593	)
	Deferred tax asset valuation allowance	(3,182		)	5,256			4,238
	Foreign earnings taxed at U.S. rates	403			1,966			3,533
	Foreign earnings taxed at different rates	(540		)	(3,315		)	417
	State taxes, net of Federal benefit	18			34			2
	Nondeductible stock option expense	244			322			365
	Uncertain tax position reserve release	(188		)	(579		)	(511		)
	Foreign tax credits	—			—			(1,147		)
	Other	7			(195		)	180
	Provision for (benefit from) income taxes	$	339		$	(542	)	$	484
	Deferred tax assets as of December 31 are comprised of the following (in thousands):
		2014			2013
	Net operating loss carryforwards	$	161,422		$	164,105
	Reserves not currently deductible	7,547			7,367
	Tax credit carryforwards	849			849
	Depreciation	6,006			6,663
	Deferred revenue	1,186			1,974
	Other	(161		)	611
	Total deferred tax asset	176,849			181,569
	Valuation allowance	(176,786		)	(181,499		)
	Net deferred tax asset	63			70
	Deferred tax liability	(192		)	(49		)
	Net deferred tax asset (liability)	$	(129	)	$	21
	The valuation allowance as of December 31, 2014 and 2013 is against all deferred tax assets for all jurisdictions except Korea. Our valuation allowance was determined in accordance with the applicable authoritative guidance, which requires an assessment of both positive and negative evidence when determining whether it is more likely than not that deferred assets are recoverable, with such assessment being required on a jurisdiction-by-jurisdiction basis. In assessing the need for a valuation allowance in the current year, management considered historical levels of income and losses, expectations and risks associated with estimates of future taxable income and ongoing prudent and feasible tax planning strategies. Factors considered in providing a valuation allowance include the lack of a significant history of consistent profits, the cyclical nature of the overall semiconductor market thereby negatively impacting our ability to sustain or grow revenues and earnings and the lack of carry-back capacity to realize these assets. Based on the absence of sufficient positive objective evidence, management is unable to assert that it is more likely than not that we will generate sufficient taxable income to realize these remaining net deferred assets. The amount of the deferred tax asset valuation allowance, however, could be reduced in future periods to the extent that future taxable income is realized.
	As of December 31, 2014, we had Federal and state net operating loss carryforwards of approximately $453.4 million and $97.1 million, respectively, which will begin expiring in 2018 for Federal and 2015 for state. We also have foreign net operating loss carryforwards in Canada and Germany of approximately $45.0 million and $28.1 million, respectively. Canada's net operating loss carryforwards begin expiring in 2026. The German net operating loss carryforward has an indefinite carryover life.
	Our net operating losses include those acquired as a result of our acquisitions of Vortek, STEAG Semiconductor Division, CFM and Concept Systems Design, Inc. ("Concept"). The Federal and state net operating losses acquired from the STEAG Semiconductor Division, CFM and Concept are also subject to change in control limitations as defined in Section 382 of the Internal Revenue Code. If certain substantial changes in our ownership occur, there would be an additional annual limitation on the amount of the net operating loss carryforwards that can be utilized.
	As of December 31, 2014, we had research credit carryforwards of approximately $2.7 million and $4.0 million for Federal and state income tax purposes, respectively. If not utilized, the Federal carryforward will expire in various amounts beginning in 2017. The California tax credit can be carried forward indefinitely.
	We provide U.S. income taxes on the earnings of foreign subsidiaries unless the subsidiaries' earnings are considered indefinitely reinvested outside the U.S. As of December 31, 2014, U.S. income taxes were not provided for on a cumulative total of $0.5 million of undistributed earnings for certain foreign subsidiaries. If these earnings were repatriated, we would be subject to additional U.S. income taxes (subject to an adjustment for foreign tax credits). It is not practical to determine the income tax liability that might be incurred if these earnings were to be repatriated. We intend to permanently reinvest all foreign unremitted earnings of foreign subsidiaries outside of the U.S., except for Germany, Korea and Canada. Our indefinitely reinvested non-U.S. earnings have been deployed in active business operations, and it is unlikely that we will repatriate any portion of our indefinitely reinvested non-U.S. earnings in the future.
	As of December 31, 2014, our total unrecognized tax benefits were approximately $25.1 million exclusive of interest and penalties described below. Included in the $25.1 million is approximately $0.2 million of unrecognized tax benefits (net of Federal benefit), that if recognized, would favorably affect the effective tax rate in a future period before consideration of changes in the valuation allowance. We anticipate there will be no significant decrease in our unrecognized tax benefits within the next twelve months.
	Our practice is to recognize interest and/or penalties related to unrecognized tax benefits in income tax expense. Provisions for income taxes included estimated interest of $0.1 million for each of the years ended December 31, 2014, 2013 and 2012. As of December 31, 2014 and 2013, we had $0.1 million and $0.1 million, respectively, accrued for estimated interest. We had no accruals for estimated penalties as of December 31, 2014 and 2013.
	We are subject to United States Federal income tax as well as to income taxes in Germany, Korea and various other foreign and U.S. state jurisdictions. Our Federal and state income tax returns are generally not subject to examination by tax authorities for years before 2011 and 2010, respectively. However, due to the fact that we have net operating losses and credits carried forward, certain items attributable to technically closed years are still subject to adjustment by the relevant taxing authority through an adjustment to the tax attributes carried forward to open years. Our German and Korea income tax returns are generally not subject to examination by tax authorities before 2009. We had no material tax audits in progress as of December 31, 2014.
	A reconciliation of unrecognized tax benefits is as follows (in thousands):
		Years Ended December 31,
		2014			2013			2012
	Balance at the beginning of the year	$	25,500		$	25,900		$	26,200
	Tax positions related to current and prior years:
	Additions	—			1,000			100
	Reductions	(100		)	(100		)	—
	Expiration of statutes of limitations	(300		)	(1,300		)	(400		)
	Balance at the end of the year	$	25,100		$	25,500		$	25,900

NET_INCOME_LOSS_PER_SHARE

NET INCOME (LOSS) PER SHARE	12 Months Ended
	Dec. 31, 2014
Earnings Per Share [Abstract]
Net Income (Loss) Per Share	NET INCOME (LOSS) PER SHARE
	We present both basic and diluted net income (loss) per share on the face of our consolidated statements of operations in accordance with the authoritative guidance on earnings per share. Basic net income (loss) per share is computed by dividing net income (loss) by the weighted-average number of shares of common stock outstanding for the period. Diluted net income (loss) per share is computed using the weighted-average number of shares of common stock outstanding plus the effect of common stock equivalents, unless the common stock equivalents are anti-dilutive. The potential dilutive shares of our common stock are determined using the treasury stock method. Under the treasury stock method, the amount the employee must pay for exercising stock options, the amount of compensation cost yet to be recognized for future service, and the amount of tax benefits that is to be recorded when the award becomes deductible are assumed be used to repurchase shares.
	The following table presents the computation of net income (loss) per share of common stock (in thousands, except for per share data):
		Years Ended December 31,
		2014		2013			2012
	Basic and diluted net income (loss) per share of common stock:
	Numerator:
	Net income (loss)	$	9,881	$	(10,975	)	$	(19,319	)
	Denominator:
	Weighted-average shares outstanding - basic	71,897		58,944			58,538
	Effect of dilutive stock options and restricted stock units	1,506		—			—
	Weighted-average shares outstanding - diluted	73,403		58,944			58,538
	Net income (loss) per share of common stock:
	Basic	$	0.14	$	(0.19	)	$	(0.33	)
	Diluted	$	0.13	$	(0.19	)	$	(0.33	)
	For the year ended December 31, 2014, options and RSUs totaling 2.3 million were excluded from diluted net income per share because their inclusion would have been anti-dilutive. For the year ended December 31, 2013 and 2012, options to purchase our common stock and restricted stock units totaling 4.7 million and 6.5 million, respectively, were excluded from diluted net loss per share because their inclusion would have been anti-dilutive, since we had net losses for each of the years ended December 31, 2013 and 2012. Accordingly, basic and diluted net loss per share were the same for the years ended December 31, 2013 and 2012.

SUPPLEMENTARY_FINANCIAL_INFORM

SUPPLEMENTARY FINANCIAL INFORMATION	12 Months Ended
	Dec. 31, 2014
Quarterly Financial Information Disclosure [Abstract]
Supplementary Financial Information	Supplementary Financial Information
	Selected Quarterly Consolidated Financial Data (Unaudited)
	The following tables set forth our unaudited condensed consolidated statements of operations data for the eight quarterly periods ended December 31, 2014. We have prepared this unaudited information on a basis consistent with our audited consolidated financial statements, reflecting all normal recurring adjustments that we consider necessary for a fair presentation of our financial position and operating results for the fiscal quarters presented. Basic and diluted income (loss) per share is computed independently for each of the quarters presented. Therefore, the sum of quarterly basic and diluted per share information may not equal annual basic and diluted income (loss) per share.
	The following tables set forth selected unaudited financial data for each quarter for the last two fiscal years (in thousands, except for per share amounts):
		Three Months Ended
		30-Mar-14			29-Jun-14			28-Sep-14			31-Dec-14
	Net revenue	$	43,198		$	42,029		$	38,430		$	54,747
	Gross margin	$	14,646		$	13,296		$	12,998		$	17,877
	Income from operations	$	2,701		$	2,049		$	546		$	4,817
	Net income	$	2,465		$	1,916		$	537		$	4,963
	Net income per share:
	Basic	$	0.04		$	0.03		$	0.01		$	0.07
	Diluted	$	0.04		$	0.03		$	0.01		$	0.07
	Shares used in computing net income per share:
	Basic	66,275			73,532			73,731			73,861
	Diluted	67,971			74,679			75,023			75,486
		Three Months Ended
		31-Mar-13			30-Jun-13			29-Sep-13			31-Dec-13
	Net revenue	$	20,237		$	24,574		$	33,840		$	40,783
	Gross margin	$	4,368		$	8,467		$	11,424		$	13,147
	Income (loss) from operations	$	(9,753	)	$	(3,059	)	$	(230	)	$	2,029
	Net income (loss)	$	(9,508	)	$	(3,567	)	$	(412	)	$	2,512
	Net income (loss) per share:
	Basic	$	(0.16	)	$	(0.06	)	$	(0.01	)	$	0.04
	Diluted	$	(0.16	)	$	(0.06	)	$	(0.01	)	$	0.04
	Shares used in computing net income (loss) per share:
	Basic	58,728			58,891			59,024			59,127
	Diluted	58,728			58,891			59,024			60,830

SCHEDULE_II_VALUATION_AND_QUAL

SCHEDULE II - VALUATION AND QUALIFYING ACCOUNTS	12 Months Ended
	Dec. 31, 2014
Valuation and Qualifying Accounts [Abstract]
Schedule II - Valuation and Qualifying Accounts - Allowance for Doubtful Accounts	SCHEDULE II
	VALUATION AND QUALIFYING ACCOUNTS
	Allowance for Doubtful Accounts
	(in thousands)
	Year Ended December 31,	Balance at Beginning of Year		Charged (Credited) to Income			Deduction and Other			Balance at End of Year
	2014	$	704	$	—		$	(35	)	$	669
	2013	$	541	$	163		$	—		$	704
	2012	$	684	$	(143	)	$	—		$	541

BASIS_OF_PRESENTATION_AND_SIGN1

BASIS OF PRESENTATION AND SIGNIFICANT ACCOUNTING POLICIES (Policies)	12 Months Ended
	Dec. 31, 2014
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation
	The consolidated financial statements include the accounts of Mattson and all our subsidiaries. All inter-company balances and transactions have been eliminated. Our fiscal year ends on December 31. Our interim fiscal quarters are based upon the first quarter ending on the Sunday closest to March 31, with the second and third fiscal quarters each being exactly 13 weeks long.
Use of Estimates	Use of Estimates
	The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America ("U.S. GAAP") requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenue and expenses during the reported periods. We evaluate our estimates on an ongoing basis, including those related to the useful lives and fair value of long-lived assets, estimates used to determine facility lease loss liabilities, measurement of warranty obligations, valuation allowances for deferred tax assets, the fair value of stock-based compensation, estimates for allowance for doubtful accounts, and valuation of excess and obsolete inventories. Our estimates and assumptions can be subjective and complex and, consequently, actual results could differ materially from those estimates.
Reclassifications	Reclassifications
	For presentation purposes, certain prior period amounts have been reclassified to conform to the reporting in the current period financial statements. These reclassifications do not affect our net income, cash flows or stockholders' equity.
Cash and Cash Equivalents	Cash and Cash Equivalents
	We consider all highly liquid investments purchased with an original maturity of three months or less to be cash equivalents. Our cash and cash equivalents are carried at fair market value, and consist primarily of cash balances and high-grade money market funds.
Concentration of Credit Risk	Concentration of Credit Risk
	We maintain our cash and cash equivalents with several financial institutions. Deposits held with banks may exceed the amount of insurance provided by the Federal Deposit Insurance Corporation on such deposits. Generally these deposits may be redeemed upon demand and are maintained with financial institutions with reputable credit.
	We may invest in a variety of financial instruments, such as U.S. treasury bills and notes, commercial paper, money market funds and corporate bonds. We limit the amount of credit exposure to any one financial institution or commercial issuer. Historically, we have not experienced significant losses on these investments.
	Our trade accounts receivable are concentrated with companies in the semiconductor industry and are derived from sales in the U.S., Asia and Europe.
Allowance for Doubtful Accounts	Allowance for Doubtful Accounts
	We perform ongoing credit evaluations of our customers and record specific allowances for doubtful accounts when a customer is unable to meet its financial obligations, as in the case of bankruptcy filings or deteriorated financial position. We estimate the allowance for doubtful accounts for all other customers based on factors such as current trends, the length of time the receivables are past due and historical collection experience. We write-off a receivable when all rights, remedies and recourses against the account and its principals are exhausted and record a benefit when previously reserved accounts are collected.
Fair Value Measurements of Assets and Liabilities	Fair Value Measurements of Assets and Liabilities
	We measure certain of our assets and liabilities at fair value, using observable market data. The authoritative guidance on fair value measurement defines fair value as an exit price, representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date, and establishes a valuation hierarchy based on the level of independent objective evidence available regarding the value of assets or liabilities. The authoritative guidance also establishes three classes of assets or liabilities: Level 1 consisting of assets and liabilities for which there are quoted prices for identical instruments in active markets; Level 2 consisting of assets and liabilities for which observable inputs other than Level 1 inputs are used such as prices for similar assets or liabilities in active markets or for identical assets or liabilities in less active markets and model-derived valuations for which the variables are derived from or corroborated by observable market data; and Level 3 consisting of assets or liabilities for which there are unobservable inputs to the valuation methodology that are significant to the measurement of the fair value. The category within the valuation hierarchy is based on the lowest level of input that is significant to the fair value measurement.
Inventory	Inventories
	Inventories are stated at the lower of cost or market, with cost determined on a first-in, first-out basis, and include material, labor and manufacturing overhead costs. Finished goods are reported as inventories until title transfers to the customer. Under our terms of sale, title generally transfers when we complete physical transfer of the products to the freight carrier, unless other customer practices or terms and conditions prevail. All inter-company profits pertaining to the sales and purchases of inventory among our subsidiaries are eliminated from the consolidated financial statements.
	We assess the valuation of all inventories, including manufacturing raw materials, work-in-process, finished goods and spare parts, at the end of each reporting period. Although we attempt to forecast future inventory demand, given the competitive pressures and cyclical nature of the semiconductor industry, there may be significant unanticipated changes in demand or technological developments that could have a significant impact on the value of our inventories and reported operating results in future periods. The carrying value of our inventory is reduced for estimated excess and obsolescence, which is the difference between its cost and the estimated market value based upon assumptions about future demand. We evaluate the inventory carrying value for potential excess and obsolete inventory exposures by analyzing historical and anticipated demand. In addition, inventories are evaluated for potential obsolescence due to the effect of known and anticipated engineering change orders and new products. If actual demand were to be substantially lower than estimated, additional inventory adjustments for excess or obsolete inventory might be required, which could have a material adverse effect on our business, financial condition and results of operations.
	Inventory includes evaluation tools placed at customer sites as part of our marketing efforts. We typically amortize the cost of the evaluation tools over an estimated period of five years, taking into consideration the estimated cost to refurbish the tools and the estimated net realizable value of the tools. The amortization charges are reported as selling, general and administrative expenses.
Property and Equipment	Property and Equipment
	Property and equipment are stated at cost. Depreciation is computed using the straight-line method based upon the estimated useful lives of the assets, which range from three to seven years. Leasehold improvements are amortized using the straight-line method over the useful lives or the term of the related lease, whichever is shorter.
	Depreciation expense was $2.2 million, $2.2 million and $2.7 million for the years ended December 31, 2014, 2013 and 2012, respectively. When assets are retired or otherwise disposed of, the assets and the associated accumulated depreciation are removed from the accounts. Repair and maintenance costs are expensed as incurred.
Long-Lived Assets	Long-Lived Assets
	We review our long-lived assets, including property and equipment and intangibles, for impairment whenever events or changes in circumstances indicate that the carrying amounts of these assets may 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 to be recognized is measured based on the amount by which the carrying amount of the asset exceeds its fair value.
Warranty	Warranty
	The warranty we offer on equipment sales is generally twelve months, except where previous customer agreements state otherwise. A provision for the estimated cost of warranty, based on historical costs, is recorded as a cost of goods sold when the revenue is recognized for the sale of the related equipment. Our warranty obligations require us to repair or replace defective products or parts during the warranty period at no cost to the customer. The actual system performance and/or field expense profiles may differ from historical experience, and in those cases we adjust our warranty reserves accordingly. Actual warranty reserves and settlements against reserves are highly dependent on our equipment volumes.
Revenue Recognition	Revenue Recognition
	We derive revenues from the following primary sources - equipment (tool or system) sales, spare part sales and service and maintenance contracts. In accordance with the authoritative guidance on revenue recognition, we recognize revenue on equipment sales as follows: 1) for equipment sales of existing products with new specifications and for sales of new products, revenue is recognized upon customer acceptance; 2) for equipment sales to existing customers with previously demonstrated equipment acceptance, or equipment sales to new customers purchasing equipment with established reliability, we recognize revenue on a multiple element approach in which revenue is recognized upon the delivery of the separate elements to the customer. The revenue we recognize on a delivered element is limited to the amount that is not contingent upon the delivery of additional items such as installation and customer acceptance, and upon transfer of title. For equipment sales we generally recognize revenue for 90 percent of the total invoice amount as revenue upon shipment while 100 percent of the equipment's cost is recognized upon shipment. The remaining portion, generally 10 percent of the total invoice amount, is contingent upon customer acceptance and is recognized once installation services are completed and final customer acceptance of the equipment is received.
	The revenue relating to the undelivered elements is deferred using the relative selling price method, which allocates revenue to each element using the estimated selling prices for the deliverables when vendor-specific objective evidence or third-party evidence is not available. We have determined that the fair value of installation services is substantially less than the 10 percent of the total invoice amount typically assigned to the installation element in our customer agreements. As such, since the amount collectible upon successful installation and customer acceptance exceeds the fair value of the installation services, we defer the amount collectible upon successful installation and customer acceptance.
	From time to time, we allow customers to evaluate equipment, with the customer maintaining the right to return the equipment at its discretion with limited or no penalty. For this type of arrangement, we do not recognize revenue until customer acceptance is received. For spare parts, we recognize revenue upon shipment. For service and maintenance contracts, we recognize revenue on a straight-line basis over the service period of the related contract or as services are performed. In all cases, revenue is only recognized when persuasive evidence of an arrangement exists, delivery has occurred, the price is fixed or determinable and collectability is reasonably assured. Accounts receivable for which revenue has not been recognized are classified as advance billings.
Research Development and Engineering Expenses	Research, Development and Engineering Expenses
	Research, development and engineering expenses include the personnel-related costs and outside consulting expenses associated with the research, development and engineering of new products and enhancements to existing products, facility related costs and other corporate allocations. These costs are expensed as incurred.
Restructuring	Restructuring
	We recognize expenses related to employee termination benefits when the benefit arrangement is communicated to the employee and no significant future services are required of the employee. If an employee is required to render service until a specific termination date, which goes beyond the legal requirement or contractual notice period, in order to receive the termination benefits, the fair value of the associated liability would be recognized ratably over the future service period. Severance costs are determined in accordance with local statutory requirements and our policies.
	We recognize the present value of facility lease termination obligations, net of estimated sublease income and other exit costs, when there are future lease payments with no future economic benefit. Sublease income is estimated based on current market rates for similar properties. If we are unable to sublease the facility on a timely basis or if we are forced to sublease the facility at lower rates due to changes in market conditions, we would adjust the restructuring liability accordingly.
Share-based Compensation	Stock-Based Compensation
	We measure the fair value of all stock-based awards, including stock options, restricted stock units, and purchase rights under our employee stock purchase plan, on the date of grant and recognize the related stock-based compensation expense on a straight-line basis over the requisite service period, which is generally the vesting period.
	We use the Black-Scholes option-pricing model to determine the fair value of certain of our stock-based awards. The determination of fair value using the Black-Scholes model is affected by our stock price as well as assumptions regarding a number of complex and subjective variables, which includes expected stock price volatility over the term of the awards, actual and projected employee exercise and cancellation behaviors, risk-free interest rates, and expected dividends.
	We estimate the expected life of options based on an analysis of our historical experience of employee exercise and post-vesting termination behavior considered in relation to the contractual life of the option; expected volatility is based on the historical volatility of our common stock; and the risk-free interest rate is equal to the U.S. Treasury rate with a maturity approximating the expected life of the option. We do not currently pay cash dividends on our common stock and do not anticipate doing so in the foreseeable future; accordingly, the expected dividend yield is zero.
	We estimate forfeiture rates on stock-based awards at the time of grant and revise those estimates in subsequent periods if actual forfeitures differ from those estimates. Such forfeiture estimates are based on historical experience. If the assumptions for estimating stock-based compensation expense change in future periods, the amount of future stock-based compensation may differ significantly from the amount that we recorded in the current and prior periods.
Foreign Currency	Foreign Currency
	The functional currencies of our foreign subsidiaries are their local currencies. All assets and liabilities of these foreign operations are translated into the U.S. dollar using exchange rates in effect at the end of the period, and revenues and costs are translated using average exchange rates for the period. Gains or losses from translation of foreign operations where the local currencies are the functional currency are included as a component of accumulated other comprehensive income in the accompanying consolidated balance sheets. Foreign currency transaction gains and losses are recorded in other income (expense), net in the accompanying consolidated statements of operations.
Income Tax	Income Taxes
	We provide for income taxes in accordance with the authoritative guidance, which requires a liability-based approach in accounting for income taxes. Deferred income tax assets and liabilities are recorded based on the differences between the financial statement and tax bases of assets and liabilities using enacted tax rates. Valuation allowances are provided against deferred income tax assets, which are not likely to be realized.
	We recognize the tax benefit from an uncertain tax position only if it is more likely than not that the tax position will be sustained on examination by taxing authorities, based on the technical merits of the position. The tax benefits recognized in the financial statements from such a position are measured based on the largest benefit that has a greater than fifty percent likelihood of being realized upon ultimate resolution.
Recent Accounting Pronouncements	Recent Accounting Pronouncements
	In May 2014, the FASB issued ASU 2014-09, Revenue from Contracts with Customers. The FASB issued ASU No. 2014-09 to clarify the principles for recognizing revenue and to develop a common revenue standard for GAAP and International Financial Reporting Standards. The standard outlines a single comprehensive model for entities to use in accounting for revenue arising from contracts with customers and supersedes the most current revenue recognition guidance. This guidance is effective for fiscal years and interim periods within those years beginning after December 15, 2016, which is effective for us as of the first quarter of 2017. We are currently evaluating the impact that the implementation of this standard will have on our financial statements.

BALANCE_SHEET_DETAILS_Tables

BALANCE SHEET DETAILS (Tables)	12 Months Ended
	Dec. 31, 2014
Balance Sheet Related Disclosures [Abstract]
Summary of Components of Inventories	Components of inventories as of December 31 are shown below (in thousands):
		2014			2013
	Inventories:
	Purchased parts and raw materials	$	28,143		$	26,842
	Work-in-process	10,832			4,260
	Finished goods	1,604			3,024
		$	40,579		$	34,126
Summary of Components of Prepaid Expense and Other Current Assets	Components of prepaid expenses and other current assets as of December 31 are shown below (in thousands):
		2014			2013
	Prepaid expenses and other current assets:
	Value-added tax	$	4,184		$	2,134
	Other current assets	5,583			3,133
		$	9,767		$	5,267
Summary of Components of Property and Equipment	Components of property and equipment as of December 31 are shown below (in thousands):
		2014			2013
	Property and equipment, net:
	Machinery and equipment	$	40,777		$	42,329
	Furniture and fixtures	9,079			9,908
	Leasehold improvements	17,646			18,626
		67,502			70,863
	Less: accumulated depreciation	(59,968		)	(61,647		)
		$	7,534		$	9,216
Summary of Components of Other Current Liabilities	Components of other current liabilities as of December 31 are shown below (in thousands):
		2014			2013
	Other current liabilities:
	Warranty	$	2,803		$	1,786
	Value-added tax	1,547			358
	Accrued restructuring charge - current	366			812
	Other	1,914			1,166
		$	6,630		$	4,122

FAIR_VALUE_MEASUREMENT_Tables

FAIR VALUE MEASUREMENT (Tables)	12 Months Ended
	Dec. 31, 2014
Fair Value Disclosures [Abstract]
Assets and Liabilities Measured on Recurring Basis	Assets and liabilities measured at fair value on a recurring basis are shown in the table below by their corresponding balance sheet captions and consisted of the following types of instruments as of December 31 (in thousands):
		2014				2013
		Fair Value Measurements at				Fair Value Measurements at
		Reporting Date Using				Reporting Date Using
		(Level 1)		Total		(Level 1)		Total
	Assets measured at fair value:
	Cash and cash equivalents:
	Money market funds	$	7,007	$	7,007	$	5	$	5
	Restricted cash:
	Money market funds	1,806		1,806		1,875		1,875
	Total assets measured at fair value	$	8,813	$	8,813	$	1,880	$	1,880

INTANGIBLE_ASSETS_Tables

INTANGIBLE ASSETS (Tables)	12 Months Ended
	Dec. 31, 2014
Intangible Assets, Net (Excluding Goodwill) [Abstract]
Identified Intangible Assets	Identified intangible assets consisted of the following as of December 31 (in thousands):
		2014			2013
	Developed technology	$	1,250		$	1,250
	Accumulated amortization	(1,250		)	(1,000		)
		$	—		$	250

RESTRUCTURING_AND_OTHER_CHARGE1

RESTRUCTURING AND OTHER CHARGES (Tables)	12 Months Ended
	Dec. 31, 2014
Restructuring Charges [Abstract]
Summary of Changes in Restructuring Accrual	The following table summarizes changes in our restructuring accrual for the years ended December 31, 2014, 2013 and 2012 (in thousands):
		Employee			Contract			Other			Total
		Severance			Termination			Costs
		Costs			Costs
	Balance at December 31, 2011	$	82		$	2,661		$	—		$	2,743
	Restructuring charges (1)	4,011			355			704			5,070
	Payments	(2,190		)	(1,420		)	(474		)	(4,084		)
	Write-off of long-term assets (1)	—			—			(230		)	(230		)
	Reserve adjustments	102			4			—			106
	Balance at December 31, 2012	2,005			1,600			—			3,605
	Restructuring charges	2,413			825			424			3,662
	Payments	(4,406		)	(1,322		)	(399		)	(6,127		)
	Reserve adjustments	(12		)	—			(25		)	(37		)
	Balance at December 31, 2013	—			1,103			—			1,103
	Restructuring charges	506			(94		)	—			412
	Payments	(358		)	(739		)	—			(1,097		)
	Reserve adjustments	(20		)	(32		)	—			(52		)
	Balance at December 31, 2014	$	128		$	238		$	—		$	366
	(1) During 2012, we recorded a $0.2 million charge related to impairment of property and equipment resulting from the transfer of our research, development and prototype production of the Millios system to our facility in Dornstadt, Germany and the consolidation of global manufacturing in our facility in Fremont, California.

COMMITMENTS_AND_CONTINGENCIES_

COMMITMENTS AND CONTINGENCIES (Tables)	12 Months Ended
	Dec. 31, 2014
Commitments and Contingencies Disclosure [Abstract]
Summary of Changes in Product Warranty Accrual	The following table summarizes changes in our product warranty accrual for the years ended December 31 (in thousands):
		2014			2013			2012
	Beginning balance	$	1,786		$	1,691		$	3,419
	Warranties issued in the period	2,783			2,031			2,242
	Costs to service warranties	(3,059		)	(1,981		)	(4,286		)
	Warranty accrual adjustments	1,293			45			316
	Ending balance	$	2,803		$	1,786		$	1,691
Schedule of Minimum Annual Lease Commitments with Respect to Operating Leases	We hold various operating leases related to our worldwide facilities and equipment. Our minimum annual lease commitments with respect to our operating leases were as follows as of December 31, 2014 (in thousands):
	Year Ending December 31,	Minimum Future Lease Payments			Sublease Rental Income			Minimum Future Lease Payments
	2015	$	3,356		$	(179	)	$	3,177
	2016	2,774			—			2,774
	2017	3,054			—			3,054
	2018	717			—			717
	2019	716			—			716
	Thereafter	716			—			716
		$	11,333		$	(179	)	$	11,154

STOCKHOLDERS_EQUITY_Tables

STOCKHOLDERS' EQUITY (Tables)	12 Months Ended
	Dec. 31, 2014
Equity [Abstract]
Schedule of Activity in Accumulated Other Comprehensive Income	The activity in accumulated other comprehensive income ("AOCI") for the years ended December 31 is as follows (thousands):
		2014			2013			2012
	Foreign currency translation adjustments:
	Balance at beginning of period	$	20,830		$	20,978		$	20,466
	Reclassification to earnings, net of tax impact	—			(488		)	—
	Change in currency translation adjustment, net of tax	(2,659		)	340			512
	Balance at end of period	18,171			20,830			20,978
	Unrealized investment gain:
	Balance at beginning of period	—			29			6
	Reclassification to earnings, net of tax	—			(29		)	(6		)
	Changes in unrealized investment gain, net of tax	—			—			29
	Balance at end of period	—			—			29
	Accumulated other comprehensive income end of period	$	18,171		$	20,830		$	21,007

EMPLOYEE_STOCK_PLANS_Tables

EMPLOYEE STOCK PLANS (Tables)	12 Months Ended
	Dec. 31, 2014
Employee Service Share-based Compensation, Aggregate Disclosures [Abstract]
Summary of Stock Option Activity	The following table summarizes the stock option activity under all of our equity incentive plans for the years ended December 31, 2014 and 2013:
		Number of Shares		Weighted-			Weighted Average Remaining Contractual Life		Aggregate Intrinsic Value
				Average
				Exercise
				Price Per Share
		(thousands)					(years)		(thousands)
	Outstanding at December 31, 2012	7,614		$	3.34
	Granted	1,579		1.4
	Exercised	(405	)	1.1
	Forfeited or expired	(3,795	)	4.29
	Outstanding at December 31, 2013	4,993		$	2.18		4.9		$	5,281
	Granted	746		2.42
	Exercised	(486	)	1.03
	Forfeited or expired	(333	)	7.01
	Outstanding at December 31, 2014	4,920		$	2.01		4.2		$	7,513
	Vested and expected to vest at December 31, 2014	4,586		$	2.01		4.1		$	7,040
	Exercisable at December 31, 2014	3,175		$	2.06		3.6		$	4,907
Schedule of Supplemental Information Pertaining to Stock Options	The following table provides supplemental information pertaining to our stock options for the years ended December 31 (in thousands, except weighted-average fair values):
		2014			2013			2012
	Weighted-average fair value of options granted	$	1.24		$	0.87		$	0.95
	Intrinsic value of options exercised	$	685		$	386		$	211
	Cash received from options exercised	$	502		$	445		$	238
Summary of Restricted Stock Unit Activity	The following table summarizes RSU activity under all of our equity incentive plans for the years ended December 31, 2014 and 2013:
		Number of Shares		Weighted Average Grant Date Fair Value
		(thousands)
	Outstanding at December 31, 2012	32		$	1.28
	Granted	416		$	1.46
	Released	(8	)	$	1.16
	Forfeited or Expired	(11	)	$	1.6
	Outstanding at December 31, 2013	429		$	1.45
	Granted	697		$	2.42
	Released	(232	)	$	1.99
	Forfeited or Expired	(17	)	$	2.49
	Outstanding at December 31, 2014	877		$	2.06

STOCKBASED_COMPENSATION_Tables

STOCK-BASED COMPENSATION (Tables)	12 Months Ended
	Dec. 31, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Summary of Black-Scholes Valuation Model used to Determine Fair Value of Stock Options	The Black-Scholes model requires the input of highly subjective assumptions, which are summarized in the table below for the years ended December 31:
		2014		2013	2012
	Expected dividend yield	—		—	—
	Expected stock price volatility	67%		83%	82%
	Risk-free interest rate	1.30%		0.90%	0.50%
	Expected life of options in years	4		4.4	1.5 - 5
Schedule of Stock-based Compensation	Our stock-based compensation for the years ended December 31 was as follows (in thousands):
		2014			2013		2012
	Stock-based compensation by type of award:
	Stock options	$	994		$	1,289	$	1,527
	Restricted stock units	484			124		18
	Employee stock purchase plan	48			20		20
		$	1,526		$	1,433	$	1,565
	Stock-based compensation by category of expense:
	Cost of goods sold	$	40		$	52	$	68
	Research, development and engineering	181			254		308
	Selling, general and administrative	1,305			1,127		1,189
		$	1,526		$	1,433	$	1,565

GEOGRAPHIC_AND_CUSTOMER_CONCEN1

GEOGRAPHIC AND CUSTOMER CONCENTRATION INFORMATION (Tables)	12 Months Ended
	Dec. 31, 2014
Geographic and Customer Concentration Information [Abstract]
Summary of Net Revenue by Geographic Areas Based on the Installation Locations of the Systems and the Location of Services Rendered	The following table summarizes net revenue by geographic areas based on the installation locations of the systems and the location of services rendered (in thousands, except percentages):
		For the Years Ended December 31,
		2014				2013			2012
		Amount		Percent		Amount		Percent	Amount		Percent
	Net revenue:
	United States	$	25,716	14		$	12,350	10	$	17,476	14
	Korea	87,585		49		22,173		19	47,611		38
	Taiwan	32,304		18		50,782		43	28,577		23
	China	17,369		10		20,250		17	8,562		7
	Other Asia	6,869		4		8,740		7	13,615		10
	Europe and others	8,561		5		5,139		4	10,685		8
		$	178,404	100		$	119,434	100	$	126,526	100
Summary of Geographic Information Relating to Property and Equipment, Net	Geographical information relating to our property and equipment, net, as of December 31 was as follows (in thousands):
		2014		2013
	Property and equipment, net:
	United States	$	4,140	$	4,949
	Germany	3,185		4,129
	Others	209		138
		$	7,534	$	9,216

INCOME_TAXES_Tables

INCOME TAXES (Tables)	12 Months Ended
	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Schedule of Components of Income (Loss) Before Income Taxes	The components of income (loss) before income taxes for the years ended December 31 are as follows (in thousands):
		2014			2013			2012
	Domestic income (loss)	$	7,248		$	(21,743	)	$	(20,522	)
	Foreign income	2,972			10,226			1,687
	Income (loss) before income taxes	$	10,220		$	(11,517	)	$	(18,835	)
Schedule of Provision for (Benefit from) Income Taxes	The provision for (benefit from) income taxes for the years ended December 31 consists of the following (in thousands):
		2014			2013			2012
	Current:
	Federal	$	—		$	(466	)	$	(251	)
	State	28			52			3
	Foreign	160			(125		)	254
	Total current	188			(539		)	6
	Deferred:
	Federal	—			—			—
	State	—			—			—
	Foreign	151			(3		)	478
	Total deferred	151			(3		)	478
	Provisions for (benefit from) income taxes	$	339		$	(542	)	$	484
Schedule of Provision for (Benefit from) Income Taxes Reconciliation to Amount Computed by Multiplying Income (Loss) Before Income Taxes by the U.S. Statutory Rate	The provision for (benefit from) income taxes reconciles to the amount computed by multiplying income (loss) before income taxes by the U.S. statutory rate of 35 percent as follows (in thousands):
		Years Ended December 31,
		2014			2013			2012
	Benefits at statutory rate	$	3,577		$	(4,031	)	$	(6,593	)
	Deferred tax asset valuation allowance	(3,182		)	5,256			4,238
	Foreign earnings taxed at U.S. rates	403			1,966			3,533
	Foreign earnings taxed at different rates	(540		)	(3,315		)	417
	State taxes, net of Federal benefit	18			34			2
	Nondeductible stock option expense	244			322			365
	Uncertain tax position reserve release	(188		)	(579		)	(511		)
	Foreign tax credits	—			—			(1,147		)
	Other	7			(195		)	180
	Provision for (benefit from) income taxes	$	339		$	(542	)	$	484
Schedule of Deferred Tax Assets and Liabilities	Deferred tax assets as of December 31 are comprised of the following (in thousands):
		2014			2013
	Net operating loss carryforwards	$	161,422		$	164,105
	Reserves not currently deductible	7,547			7,367
	Tax credit carryforwards	849			849
	Depreciation	6,006			6,663
	Deferred revenue	1,186			1,974
	Other	(161		)	611
	Total deferred tax asset	176,849			181,569
	Valuation allowance	(176,786		)	(181,499		)
	Net deferred tax asset	63			70
	Deferred tax liability	(192		)	(49		)
	Net deferred tax asset (liability)	$	(129	)	$	21
Schedule of Reconciliation of Unrecognized Tax Benefits	A reconciliation of unrecognized tax benefits is as follows (in thousands):
		Years Ended December 31,
		2014			2013			2012
	Balance at the beginning of the year	$	25,500		$	25,900		$	26,200
	Tax positions related to current and prior years:
	Additions	—			1,000			100
	Reductions	(100		)	(100		)	—
	Expiration of statutes of limitations	(300		)	(1,300		)	(400		)
	Balance at the end of the year	$	25,100		$	25,500		$	25,900

NET_INCOME_LOSS_PER_SHARE_Tabl

NET INCOME (LOSS) PER SHARE (Tables)	12 Months Ended
	Dec. 31, 2014
Earnings Per Share [Abstract]
Schedule of Computation of Net Income (Loss) per Share of Common Stock	The following table presents the computation of net income (loss) per share of common stock (in thousands, except for per share data):
		Years Ended December 31,
		2014		2013			2012
	Basic and diluted net income (loss) per share of common stock:
	Numerator:
	Net income (loss)	$	9,881	$	(10,975	)	$	(19,319	)
	Denominator:
	Weighted-average shares outstanding - basic	71,897		58,944			58,538
	Effect of dilutive stock options and restricted stock units	1,506		—			—
	Weighted-average shares outstanding - diluted	73,403		58,944			58,538
	Net income (loss) per share of common stock:
	Basic	$	0.14	$	(0.19	)	$	(0.33	)
	Diluted	$	0.13	$	(0.19	)	$	(0.33	)

SUPPLEMENTARY_FINANCIAL_INFORM1

SUPPLEMENTARY FINANCIAL INFORMATION (Tables)	12 Months Ended
	Dec. 31, 2014
Quarterly Financial Information Disclosure [Abstract]
Schedule of Selected Unaudited Financial Data for Each Quarter	The following tables set forth selected unaudited financial data for each quarter for the last two fiscal years (in thousands, except for per share amounts):
		Three Months Ended
		30-Mar-14			29-Jun-14			28-Sep-14			31-Dec-14
	Net revenue	$	43,198		$	42,029		$	38,430		$	54,747
	Gross margin	$	14,646		$	13,296		$	12,998		$	17,877
	Income from operations	$	2,701		$	2,049		$	546		$	4,817
	Net income	$	2,465		$	1,916		$	537		$	4,963
	Net income per share:
	Basic	$	0.04		$	0.03		$	0.01		$	0.07
	Diluted	$	0.04		$	0.03		$	0.01		$	0.07
	Shares used in computing net income per share:
	Basic	66,275			73,532			73,731			73,861
	Diluted	67,971			74,679			75,023			75,486
		Three Months Ended
		31-Mar-13			30-Jun-13			29-Sep-13			31-Dec-13
	Net revenue	$	20,237		$	24,574		$	33,840		$	40,783
	Gross margin	$	4,368		$	8,467		$	11,424		$	13,147
	Income (loss) from operations	$	(9,753	)	$	(3,059	)	$	(230	)	$	2,029
	Net income (loss)	$	(9,508	)	$	(3,567	)	$	(412	)	$	2,512
	Net income (loss) per share:
	Basic	$	(0.16	)	$	(0.06	)	$	(0.01	)	$	0.04
	Diluted	$	(0.16	)	$	(0.06	)	$	(0.01	)	$	0.04
	Shares used in computing net income (loss) per share:
	Basic	58,728			58,891			59,024			59,127
	Diluted	58,728			58,891			59,024			60,830

BASIS_OF_PRESENTATION_AND_SIGN2

BASIS OF PRESENTATION AND SIGNIFICANT ACCOUNTING POLICIES - Narrative (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Accounting Policies [Line Items]
Estimated period of amortization for the cost of inventory evaluation tools	5 years
Amortization expense	$400,000	$1,500,000	$1,000,000
Depreciation expense	2,200,000	2,200,000	2,700,000
Impairment charge related to property and equipment	0	0	200,000
General length of product warranty	12 months
Stock-based compensation expense	1,526,000	1,433,000	1,565,000
Net foreign currency transaction gain	300,000		400,000
Net foreign currency transaction loss		-600,000
Cumulative translation adjustment	$18,200,000	$20,800,000
Minimum
Accounting Policies [Line Items]
Estimated useful lives of assets	3 years
Maximum
Accounting Policies [Line Items]
Estimated useful lives of assets	7 years
Customer concentration risk | Accounts receivable
Accounting Policies [Line Items]
Number of major customers	1	2
Net accounts receivable, major customer D | Customer concentration risk | Accounts receivable
Accounting Policies [Line Items]
Percentage of net accounts receivable	74.00%	61.00%
Net accounts receivable, major customer E | Customer concentration risk | Accounts receivable
Accounting Policies [Line Items]
Percentage of net accounts receivable		23.00%
Equipment sales
Accounting Policies [Line Items]
Percent revenue recognized upon shipment	90.00%
Percent cost recognized upon shipment	100.00%
Percent revenue recognized upon customer acceptance	10.00%
Installation services
Accounting Policies [Line Items]
Percentage of total invoice amount typically assigned to the installation element in customer agreements	10.00%

BALANCE_SHEET_DETAILS_Narrativ

BALANCE SHEET DETAILS - Narrative (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Balance Sheet Related Disclosures [Abstract]
Restricted cash	$1,993	$2,087

BALANCE_SHEET_DETAILS_Summary_

BALANCE SHEET DETAILS - Summary of Components of Inventories (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Inventories:
Purchased parts and raw materials	$28,143	$26,842
Work-in-process	10,832	4,260
Finished goods	1,604	3,024
Inventories, net	$40,579	$34,126

BALANCE_SHEET_DETAILS_Summary_1

BALANCE SHEET DETAILS - Summary of Components of Prepaid Expense and Other Current Assets (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Prepaid expenses and other current assets:
Value-added tax	$4,184	$2,134
Other current assets	5,583	3,133
Prepaid expenses and other current assets	$9,767	$5,267

BALANCE_SHEET_DETAILS_Summary_2

BALANCE SHEET DETAILS - Summary of Components of Property and Equipment (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Property, Plant and Equipment [Line Items]
Property, and equipment, gross	$67,502	$70,863
Less: accumulated depreciation	-59,968	-61,647
Property and equipment, net	7,534	9,216
Machinery and equipment
Property, Plant and Equipment [Line Items]
Property, and equipment, gross	40,777	42,329
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Property, and equipment, gross	9,079	9,908
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property, and equipment, gross	$17,646	$18,626

BALANCE_SHEET_DETAILS_Summary_3

BALANCE SHEET DETAILS - Summary of Components of Other Current Liabilities (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Other current liabilities:
Warranty	$2,803	$1,786
Value-added tax	1,547	358
Accrued restructuring charge - current	366	812
Other	1,914	1,166
Other current liabilities	$6,630	$4,122

FAIR_VALUE_MEASUREMENT_Assets_

FAIR VALUE MEASUREMENT - Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) (Recurring, USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Assets measured at fair value:
Total assets measured at fair value	$8,813	$1,880
Money market funds
Assets measured at fair value:
Cash and cash equivalents	7,007	5
Restricted cash	1,806	1,875
Fair value measurements at reporting date, level 1
Assets measured at fair value:
Total assets measured at fair value	8,813	1,880
Fair value measurements at reporting date, level 1 | Money market funds
Assets measured at fair value:
Cash and cash equivalents	7,007	5
Restricted cash	$1,806	$1,875

INTANGIBLE_ASSETS_Identified_I

INTANGIBLE ASSETS - Identified Intangible Assets (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Finite-Lived Intangible Assets [Line Items]
Intangibles, net	$0	$250
Developed technology
Finite-Lived Intangible Assets [Line Items]
Developed technology	1,250	1,250
Accumulated amortization	-1,250	-1,000
Intangibles, net	$0	$250

INTANGIBLE_ASSETS_Narrative_De

INTANGIBLE ASSETS - Narrative (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Goodwill and Intangible Assets Disclosure [Abstract]
Amortization expense	$0.30	$0.30	$0.30

REVOLVING_CREDIT_FACLITY_Narra

REVOLVING CREDIT FACLITY - Narrative (Details) (USD $)	0 Months Ended
	Apr. 12, 2013	Oct. 21, 2014	Oct. 20, 2014	Mar. 30, 2015	Dec. 31, 2013	Dec. 31, 2014
		Quarter
Line of Credit Facility [Line Items]
Debt issuance costs	$400,000
Revolving credit facility, amount outstanding					14,000,000
Revolving credit facility
Line of Credit Facility [Line Items]
Revolving credit facility, term	3 years
Revolving credit facility, maximum borrowing capacity	25,000,000
Effective interest rate						3.25%
Percentage monthly commitment fee on unused portion of credit facility	0.38%
Revolving credit facility, amount outstanding					14,000,000	0
Alternative base rate | Federal funds effective rate | Revolving credit facility
Line of Credit Facility [Line Items]
Variable rate	0.50%
Alternative base rate | Prime rate | Revolving credit facility
Line of Credit Facility [Line Items]
Interest rate increase in an event of default	2.00%
Eurodollar rate | Revolving credit facility
Line of Credit Facility [Line Items]
Denominator of applicable margin	1
Amended agreement No. 4 | Revolving credit facility
Line of Credit Facility [Line Items]
Revolving credit facility, one time additional borrowing		25,000,000
Credit agreement, borrowing base components, percentage of eligible accounts receivable and advance billings		85.00%
Credit agreement, borrowing base components, percentage of eligible inventory minus reserves		50.00%
Revolving credit facility, minimum EBITDA		2,000,000	6,000,000
Number of consecutive quarters immediately prior to end of reporting period to determine minimum EBITDA		2
Minimum quick ratio		1
Covenant, minimum available funds		30,000,000
Commitment fee		$62,500
Amended agreement No. 4 | Alternative base rate | Revolving credit facility
Line of Credit Facility [Line Items]
Variable rate		0.00%
Amended agreement No. 4 | Eurodollar rate | Revolving credit facility
Line of Credit Facility [Line Items]
Variable rate		2.75%
Forecast | Amended agreement No. 4 | Revolving credit facility
Line of Credit Facility [Line Items]
Minimum quick ratio				1.25

RESTRUCTURING_AND_OTHER_CHARGE2

RESTRUCTURING AND OTHER CHARGES - Summary of Changes in Restructuring Accrual (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Restructuring Reserve [Roll Forward]
Restructuring Reserve - Beginning Balance	$1,103	$3,605	$2,743
Restructuring charges	412	3,662	5,070
Payments	-1,097	-6,127	-4,084
Long-lived assets write-off			-230
Reserve adjustments	-52	-37	106
Restructuring Reserve - Ending Balance	400	1,103	3,605
Employee severance costs
Restructuring Reserve [Roll Forward]
Restructuring Reserve - Beginning Balance	0	2,005	82
Restructuring charges	506	2,413	4,011
Payments	-358	-4,406	-2,190
Long-lived assets write-off			0
Reserve adjustments	-20	-12	102
Restructuring Reserve - Ending Balance	128	0	2,005
Contract termination costs
Restructuring Reserve [Roll Forward]
Restructuring Reserve - Beginning Balance	1,103	1,600	2,661
Restructuring charges	-94	825	355
Payments	-739	-1,322	-1,420
Long-lived assets write-off			0
Reserve adjustments	-32	0	4
Restructuring Reserve - Ending Balance	238	1,103	1,600
Other costs
Restructuring Reserve [Roll Forward]
Restructuring Reserve - Beginning Balance	0	0	0
Restructuring charges	0	424	704	[1]
Payments	0	-399	-474
Long-lived assets write-off			-230	[1]
Reserve adjustments	0	-25	0
Restructuring Reserve - Ending Balance	$0	$0	$0
[1]	$0.2 million charge related to impairment of property and equipment resulting from the transfer of our research, development and prototype production of the Millios system to our facility in Dornstadt, Germany and the consolidation of global manufacturing in our facility in Fremont, California.

RESTRUCTURING_AND_OTHER_CHARGE3

RESTRUCTURING AND OTHER CHARGES - Summary of Changes in Restructuring Accrual (Footnote) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2012
Restructuring Cost and Reserve [Line Items]
Long-lived assets write-off	($230)
Other costs
Restructuring Cost and Reserve [Line Items]
Long-lived assets write-off	($230)	[1]
[1]	$0.2 million charge related to impairment of property and equipment resulting from the transfer of our research, development and prototype production of the Millios system to our facility in Dornstadt, Germany and the consolidation of global manufacturing in our facility in Fremont, California.

RESTRUCTURING_AND_OTHER_CHARGE4

RESTRUCTURING AND OTHER CHARGES - Narrative (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012		Dec. 31, 2011
		facility
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$412,000	$3,662,000	$5,070,000
Number of vacated leased facilities		2
Accrued restructuring charges	400,000	1,103,000	3,605,000		2,743,000
Payments	-1,097,000	-6,127,000	-4,084,000
Restructuring reserve, current	366,000	812,000
Accrued liabilities, current
Restructuring Cost and Reserve [Line Items]
Restructuring reserve, current		800,000
Other liabilities, noncurrent
Restructuring Cost and Reserve [Line Items]
Restructuring reserve, noncurrent		300,000
Employee severance costs
Restructuring Cost and Reserve [Line Items]
Restructuring charges	506,000	2,413,000	4,011,000
Severance expense	600,000
Accrued restructuring charges	128,000	0	2,005,000		82,000
Payments	-358,000	-4,406,000	-2,190,000
Employee severance and other costs
Restructuring Cost and Reserve [Line Items]
Restructuring charges	2,800,000		4,700,000
Payments	-4,800,000		-2,700,000
Contract termination costs
Restructuring Cost and Reserve [Line Items]
Restructuring charges	-94,000	825,000	355,000
Accrued restructuring charges	238,000	1,103,000	1,600,000		2,661,000
Payments	-739,000	-1,322,000	-1,420,000
Other costs
Restructuring Cost and Reserve [Line Items]
Restructuring charges	0	424,000	704,000	[1]
Accrued restructuring charges	0	0	0		0
Payments	$0	($399,000)	($474,000)
[1]	$0.2 million charge related to impairment of property and equipment resulting from the transfer of our research, development and prototype production of the Millios system to our facility in Dornstadt, Germany and the consolidation of global manufacturing in our facility in Fremont, California.

COMMITMENTS_AND_CONTINGENCIES_1

COMMITMENTS AND CONTINGENCIES - Summary of Changes in Product Warranty Accrual (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Movement in Product Warranty, Increase (Decrease) [Roll Forward]
Beginning balance	$1,786	$1,691	$3,419
Warranties issued in the period	2,783	2,031	2,242
Costs to service warranties	-3,059	-1,981	-4,286
Warranty accrual adjustments	1,293	45	316
Ending balance	$2,803	$1,786	$1,691

COMMITMENTS_AND_CONTINGENCIES_2

COMMITMENTS AND CONTINGENCIES - Schedule of Minimum Annual Lease Commitments with Respect to Operating Leases (Details) (USD $)	Dec. 31, 2014
In Thousands, unless otherwise specified
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
2015	$3,356
2016	2,774
2017	3,054
2018	717
2019	716
Thereafter	716
Total	11,333
Operating Leases, Future Minimum Payments Due, Future Minimum Sublease Rentals, Fiscal Year Maturity [Abstract]
2015	-179
2016	0
2017	0
2018	0
2019	0
Thereafter	0
Total	-179
Operating Leases, Future Minimum Payments Due, Net Of Sublease Rentals, Fiscal Year Maturity [Abstract]
2015	3,177
2016	2,774
2017	3,054
2018	717
2019	716
Thereafter	716
Total	$11,154

COMMITMENTS_AND_CONTINGENCIES_3

COMMITMENTS AND CONTINGENCIES - Narrative (Details)

12 Months Ended

1 Months Ended

12 Months Ended

0 Months Ended

132 Months Ended

Dec. 31, 2014

Dec. 31, 2013

Apr. 30, 2013

Dec. 31, 2012

31-May-12

Apr. 30, 2012

Apr. 30, 2013

Dec. 31, 2014

Dec. 31, 2013

Dec. 31, 2012

31-May-07

Dec. 31, 2014

31-May-07

Dec. 31, 2014

Dec. 31, 2014

Dec. 31, 2014

Dec. 31, 2014

USD ($)

USD ($)

USD ($)

Regulatory violations

Regulatory violations

Regulatory violations

Exton, Pennsylvania and Vancouver, Canada

Exton, Pennsylvania and Vancouver, Canada

Exton, Pennsylvania and Vancouver, Canada

Fremont, California

Fremont, California

Fremont, California

Financial standby letter of credit

Vortek Industries

Royalty agreements

Royalty agreements

USD ($)

USD ($)

violation

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

Financial standby letter of credit

USD ($)

Vortek Industries

Vortek Industries

USD ($)

CAD

USD ($)

Loss Contingencies [Line Items]

General length of product warranty

12 months

Rent expense

$4,100,000

$3,900,000

$4,300,000

Sublease revenue

226,000

377,000

403,000

Term of contract

10 years

Operating lease initial base rent cost

1,400,000

Annual rent increase percentage

3.50%

Operating leases, future minimum payments, at end of lease term

716,000

1,500,000

Standby letter of credit

1,500,000

Maximum potential amount required to pay under outstanding standby letters of credit

1,700,000

Restricted cash

1,993,000

2,087,000

Royalty guarantees payments, percentage of net sales from certain Flash RTP products

1.40%

Potential cash payment to Canadian Minister of Industries from certain Flash RTP products in connection with acquisition of Vortek Industries, Ltd.

14,300,000

12,300,000

Cumulative royalty charges to date

400,000

Civil penalty

900,000

Payment for civil penalty

300,000

Remaining civil penalty contingency

$600,000

Suspended payment period for remaining civil penalty

1 year

Number of violations

0

STOCKHOLDERS_EQUITY_Narrative_

STOCKHOLDERS' EQUITY - Narrative (Details) (USD $)	1 Months Ended	12 Months Ended			3 Months Ended
	Feb. 28, 2014	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013	Dec. 31, 2011
Class of Stock [Line Items]
Shares issued in connection with public offering, net of offering costs (in shares)	14,100,000
Price per share (in usd per share)	$2.45
Proceeds from issuance of common stock, net	$31,700,000	$32,213,000	$576,000	$366,000
Underwriting discounts and offering expenses	2,800,000
Total purchase price		75,110,000	34,149,000	43,292,000	34,149,000	60,145,000
Other income (expense) related to liquidation of subsidiaries		335,000	-10,000	316,000
Percentage of one preferred stock to purchase of each Right		0.001
Exercise price of each Right (in usd per share)		$55
Percentage of common stock acquired by a person or group for share purchase right to become exercisable		15.00%
Redemption price of each Right (in usd per share)		$0.00
Number of common stock in exchange of each Right		1
Discount of rights to purchase common stock of acquiror		50.00%
Share purchase rights outstanding (in shares)		50,000,000
Treasury Stock
Class of Stock [Line Items]
Treasury stock, outstanding (in shares)		-4,258,000	-4,181,000	-4,181,000	-4,181,000	-4,181,000
Total purchase price		-38,083,000	-37,986,000	-37,986,000	-37,986,000	-37,986,000
Reclassification out of AOCI | Foreign currency translation adjustments
Class of Stock [Line Items]
Other income (expense) related to liquidation of subsidiaries					$500,000

STOCKHOLDERS_EQUITY_Schedule_o

STOCKHOLDERS' EQUITY - Schedule of Activity in Accumulated Other Comprehensive Income (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance at beginning of period	$20,830	$21,007
Change in currency translation adjustment, net of tax	-2,659	-148	512
Changes in unrealized investment gain, net of tax	0	-29	23
Balance at end of period	18,171	20,830	21,007
Foreign currency translation adjustments
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance at beginning of period	20,830	20,978	20,466
Reclassification to earnings, net of tax	0	-488	0
Change in currency translation adjustment, net of tax		340	512
Balance at end of period	18,171	20,830	20,978
Unrealized investment gain
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance at beginning of period	0	29	6
Reclassification to earnings, net of tax	0	-29	-6
Changes in unrealized investment gain, net of tax	0	0	29
Balance at end of period	$0	$0	$29

EMPLOYEE_STOCK_PLANS_Narrative

EMPLOYEE STOCK PLANS - Narrative (Details) (USD $)	12 Months Ended			1 Months Ended
In Millions, except Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013	31-May-12	31-May-14
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percent of options vesting on first anniversary of vesting commencement date	25.00%
Options granted in period (in shares)	700,000	1,600,000	3,100,000
Options, grant date fair value	$0.90	$1.40	$2.90
Defined contribution plan, employer discretionary contribution amount	$0.20	$0.10	$0.20
Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting rate	2.78%
Time-based restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting rate				25.00%
Grant ratio	1.75
2012 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares of additional common stock approved (in shares)					2,500,000
Number of shares reserved for issuance (in shares)					17,000,000
Number of shares available for future grant (in shares)	3,300,000
2012 Equity Incentive Plan | Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise price, as a percent of fair market value of common stock on grant date	100.00%
Percent of options vesting on first anniversary of vesting commencement date	25.00%
Vesting period	36 months
Employee requisite service period				1 year
2012 Equity Incentive Plan | Stock options | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award terms	7 years
1994 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
ESPP extended term						10 years
ESPP offering period	6 months
1994 Plan | Employee stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares reserved for issuance (in shares)	6,200,000
Number of shares available for future grant (in shares)	2,500,000
Exercise price, as a percent of fair market value of common stock on grant date	90.00%
Maximum employee subscription rate	15.00%
Maximum number of shares per employee (in shares)	4,000	2,000
Shares issued in period (in shares)	100,000	100,000	100,000
Average price of shares purchased, per share (in usd per share)	$2.17	$2.09	$1.23	2.09

EMPLOYEE_STOCK_PLANS_Summary_o

EMPLOYEE STOCK PLANS - Summary of Stock Option Activity (Details) (USD $)	12 Months Ended
In Thousands, except Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Number of Shares
Outstanding, beginning balance (in shares)	4,993,000	7,614,000
Granted (in shares)	700,000	1,600,000	3,100,000
Exercised (in shares)	-486,000	-405,000
Forfeited or expired (in shares)	-333,000	-3,795,000
Outstanding, ending balance (in shares)	4,920,000	4,993,000	7,614,000
Vested and expected to vest (in shares)	4,586,000
Exercisable (in shares)	3,175,000
Weighted-Average Exercise Price
Weighted-Average Exercise Price Per Share, beginning balance (in usd per share)	$2.18	$3.34
Weighted Average Exercise Price Per Share, Granted (in usd per share)	$2.42	$1.40
Weighted Average Exercise Price Per Share, Exercised (in usd per share)	$1.03	$1.10
Weighted Average Exercise Price Per Share, Forfeited or expired (in usd per share)	$7.01	$4.29
Weighted-Average Exercise Price Per Share, ending balance (in usd per share)	$2.01	$2.18	$3.34
Weighted Average Exercise Price, Vested and expected to vest (in usd per share)	$2.01
Weighted Average Exercise Price, Exercisable (in usd per share)	$2.06
Weighted Average Remaining Term
Weighted Average Remaining Contractual Life	4 years 2 months 12 days	4 years 10 months 24 days
Weighted Average Remaining Contractual Life, Vested and expected to vest	4 years 1 month 6 days
Weighted Average Remaining Contractual Life, Exercisable	3 years 7 months 6 days
Aggregate Intrinsic Value
Aggregate Intrinsic Value	$7,513	$5,281
Aggregate Intrinsic Value, Vested and expected to vest	7,040
Aggregate Intrinsic Value, Exercisable	$4,907

EMPLOYEE_STOCK_PLANS_Schedule_

EMPLOYEE STOCK PLANS - Schedule of Supplemental Information Pertaining to Stock Options (Details) (USD $)	12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Employee Service Share-based Compensation, Aggregate Disclosures [Abstract]
Weighted-average fair value of options granted (in usd per share)	$1.24	$0.87	$0.95
Intrinsic value of options exercised	$685	$386	$211
Cash received from options exercised	$502	$445	$238

EMPLOYEE_STOCK_PLANS_Summary_o1

EMPLOYEE STOCK PLANS - Summary of Restricted Stock Unit Activity (Details) (Restricted stock units, USD $)	12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Restricted stock units
Number of Shares
Outstanding, beginning balance	429	32
Granted (in shares)	697	416
Released (in shares)	-232	-8
Forfeited or Expired (in shares)	-17	-11
Outstanding, ending balance	877	429
Weighted Average Grant Date Fair Value
Weighted Average Grant Date Fair Value, beginning balance (in usd per share)	$1.45	$1.28
Weighted Average Grant Date Fair Value, Granted (in usd per share)	$2.42	$1.46
Weighted Average Grant Date Fair Value, Released (in usd per share)	$1.99	$1.16
Weighted Average Grant Date Fair Value, Forfeited or Expired (in usd per share)	$2.49	$1.60
Weighted Average Grant Date Fair Value, ending balance (in usd per share)	$2.06	$1.45

STOCKBASED_COMPENSATION_Summar

STOCK-BASED COMPENSATION - Summary of Black-Scholes Valuation Model used to Determine Fair Value of Stock Options (Details) (Stock options)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Black-Scholes Valuation Assumptions
Expected dividend yield	0.00%	0.00%	0.00%
Expected stock price volatility	67.00%	83.00%	82.00%
Risk-free interest rate	1.30%	0.90%	0.50%
Expected life of options in years	4 years 0 months 0 days	4 years 4 months 22 days
Minimum
Black-Scholes Valuation Assumptions
Expected life of options in years			1 year 6 months
Maximum
Black-Scholes Valuation Assumptions
Expected life of options in years			5 years

STOCKBASED_COMPENSATION_Narrat

STOCK-BASED COMPENSATION - Narrative (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected dividend yield	0.00%	0.00%	0.00%
Unrecognized stock-based compensation	$1.40
Weighted average recognition period for stock-based compensation	2 years 4 months 24 days
Restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized stock-based compensation	$1.20
Weighted average recognition period for stock-based compensation	2 years 9 months 18 days

STOCKBASED_COMPENSATION_Schedu

STOCK-BASED COMPENSATION - Schedule of Stock-based Compensation (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation	$1,526	$1,433	$1,565
Cost of goods sold
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation	40	52	68
Research, development and engineering
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation	181	254	308
Selling, general and administrative
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation	1,305	1,127	1,189
Stock options
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation	994	1,289	1,527
Restricted stock units
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation	484	124	18
Employee Stock Purchase Plan
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation	$48	$20	$20

GEOGRAPHIC_AND_CUSTOMER_CONCEN2

GEOGRAPHIC AND CUSTOMER CONCENTRATION INFORMATION - Narrative (Details)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Concentration Risk [Line Items]
Number of operating segment	1
Customer concentration risk | Net revenue
Concentration Risk [Line Items]
Number of major customers	2		2
Customer concentration risk | Net revenue | Net revenue, major customer A
Concentration Risk [Line Items]
Concentration risk percentage	61.00%	35.00%	41.00%
Customer concentration risk | Net revenue | Net revenue, major customer B
Concentration Risk [Line Items]
Concentration risk percentage		33.00%	12.00%
Customer concentration risk | Accounts receivable
Concentration Risk [Line Items]
Number of major customers	1	2
Customer concentration risk | Accounts receivable | Net accounts receivable, major customer D
Concentration Risk [Line Items]
Concentration risk percentage	74.00%	61.00%
Customer concentration risk | Accounts receivable | Net accounts receivable, major customer E
Concentration Risk [Line Items]
Concentration risk percentage		23.00%

GEOGRAPHIC_AND_CUSTOMER_CONCEN3

GEOGRAPHIC AND CUSTOMER CONCENTRATION INFORMATION - Summary of Net Revenue by Geographic Areas Based on the Installation Locations of the Systems and the Location of Services Rendered (Details) (USD $)	3 Months Ended								12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Sep. 28, 2014	Jun. 29, 2014	Mar. 30, 2014	Dec. 31, 2013	Sep. 29, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenue	$54,747	$38,430	$42,029	$43,198	$40,783	$33,840	$24,574	$20,237	$178,404	$119,434	$126,526
Geographic concentration risk | Net revenue
Revenues from External Customers and Long-Lived Assets [Line Items]
Concentration risk percentage									100.00%	100.00%	99.50%
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenue									25,716	12,350	17,476
United States | Geographic concentration risk | Net revenue
Revenues from External Customers and Long-Lived Assets [Line Items]
Concentration risk percentage									14.00%	10.00%	14.00%
Korea
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenue									87,585	22,173	47,611
Korea | Geographic concentration risk | Net revenue
Revenues from External Customers and Long-Lived Assets [Line Items]
Concentration risk percentage									49.00%	19.00%	38.00%
Taiwan
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenue									32,304	50,782	28,577
Taiwan | Geographic concentration risk | Net revenue
Revenues from External Customers and Long-Lived Assets [Line Items]
Concentration risk percentage									18.00%	43.00%	23.00%
China
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenue									17,369	20,250	8,562
China | Geographic concentration risk | Net revenue
Revenues from External Customers and Long-Lived Assets [Line Items]
Concentration risk percentage									10.00%	17.00%	7.00%
Other Asia
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenue									6,869	8,740	13,615
Other Asia | Geographic concentration risk | Net revenue
Revenues from External Customers and Long-Lived Assets [Line Items]
Concentration risk percentage									4.00%	7.00%	10.00%
Europe and others
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenue									$8,561	$5,139	$10,685
Europe and others | Geographic concentration risk | Net revenue
Revenues from External Customers and Long-Lived Assets [Line Items]
Concentration risk percentage									5.00%	4.00%	8.00%

GEOGRAPHIC_AND_CUSTOMER_CONCEN4

GEOGRAPHIC AND CUSTOMER CONCENTRATION INFORMATION - Summary of Geographic Information Relating to Property and Equipment, Net (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Revenues from External Customers and Long-Lived Assets [Line Items]
Property and equipment, net	$7,534	$9,216
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Property and equipment, net	4,140	4,949
Germany
Revenues from External Customers and Long-Lived Assets [Line Items]
Property and equipment, net	3,185	4,129
Others
Revenues from External Customers and Long-Lived Assets [Line Items]
Property and equipment, net	$209	$138

INCOME_TAXES_Schedule_of_Compo

INCOME TAXES - Schedule of Components of Income (Loss) Before Income Taxes (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Tax Disclosure [Abstract]
Domestic income (loss)	$7,248	($21,743)	($20,522)
Foreign income	2,972	10,226	1,687
Income (loss) before income taxes	$10,220	($11,517)	($18,835)

INCOME_TAXES_Schedule_of_Provi

INCOME TAXES - Schedule of Provision for (Benefit from) Income Taxes (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Current:
Federal	$0	($466)	($251)
State	28	52	3
Foreign	160	-125	254
Total current	188	-539	6
Deferred:
Federal	0	0	0
State	0	0	0
Foreign	151	-3	478
Total deferred	151	-3	478
Provisions for (benefit from) income taxes	$339	($542)	$484

INCOME_TAXES_Schedule_of_Provi1

INCOME TAXES - Schedule of Provision for (Benefit from) Income Taxes Reconciliation to Amount Computed by Multiplying Income (Loss) Before Income Taxes by the U.S. Statutory Rate (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Tax Disclosure [Abstract]
Benefits at statutory rate	$3,577	($4,031)	($6,593)
Deferred tax asset valuation allowance	-3,182	5,256	4,238
Foreign earnings taxed at U.S. rates	403	1,966	3,533
Foreign earnings taxed at different rates	-540	-3,315	417
State taxes, net of Federal benefit	18	34	2
Nondeductible stock option expense	244	322	365
Uncertain tax position reserve release	-188	-579	-511
Foreign tax credits	0	0	-1,147
Other	7	-195	180
Provisions for (benefit from) income taxes	$339	($542)	$484

INCOME_TAXES_Schedule_of_Defer

INCOME TAXES - Schedule of Deferred Tax Assets and Liabilities (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Income Tax Disclosure [Abstract]
Net operating loss carryforwards	$161,422	$164,105
Reserves not currently deductible	7,547	7,367
Tax credit carryforwards	849	849
Depreciation	6,006	6,663
Deferred revenue	1,186	1,974
Other	-161	611
Total deferred tax asset	176,849	181,569
Valuation allowance	-176,786	-181,499
Net deferred tax asset	63	70
Deferred tax liability	-192	-49
Net deferred tax asset (liability)	($129)	$21

INCOME_TAXES_Narrative_Details

INCOME TAXES - Narrative (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Operating Loss Carryforwards [Line Items]
U.S. statutory rate	35.00%
Undistributed earnings of foreign subsidiaries	$500,000
Unrecognized tax benefits	25,100,000
Unrecognized tax benefits that would impact effective tax rate	200,000
Decrease in unrecognized tax benefits within the next twelve months	0
Unrecognized tax benefits, interest on income taxes expense	100,000
Unrecognized tax benefits, interest on income taxes accrued	100,000	100,000
Accruals for estimated penalties	0	0
Federal
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	453,400,000
State
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	97,100,000
Canada | Foreign
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	45,000,000
Germany | Foreign
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	28,100,000
Research credit carryforward | Federal
Operating Loss Carryforwards [Line Items]
Tax credit carryforward	2,700,000
Research credit carryforward | State
Operating Loss Carryforwards [Line Items]
Tax credit carryforward	$4,000,000

INCOME_TAXES_Schedule_of_Recon

INCOME TAXES - Schedule of Reconciliation of Unrecognized Tax Benefits (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Balance at the beginning of the year	$25,500	$25,900	$26,200
Tax positions related to current and prior years:
Additions	0	1,000	100
Reductions	-100	-100	0
Expiration of statutes of limitations	-300	-1,300	-400
Balance at the end of the year	$25,100	$25,500	$25,900

NET_INCOME_LOSS_PER_SHARE_Sche

NET INCOME (LOSS) PER SHARE - Schedule of Computation of Net Income (Loss) per Share of Common Stock (Details) (USD $)	3 Months Ended								12 Months Ended
In Thousands, except Share data, unless otherwise specified	Dec. 31, 2014	Sep. 28, 2014	Jun. 29, 2014	Mar. 30, 2014	Dec. 31, 2013	Sep. 29, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Numerator:
Net income (loss)	$4,963	$537	$1,916	$2,465	$2,512	($412)	($3,567)	($9,508)	$9,881	($10,975)	($19,319)
Denominator:
Weighted-average shares outstanding - basic (in shares)	73,861,000	73,731,000	73,532,000	66,275,000	59,127,000	59,024,000	58,891,000	58,728,000	71,897,000	58,944,000	58,538,000
Effect of dilutive stock options and restricted stock units (in shares)									1,506,000	0	0
Weighted-average shares outstanding - diluted (in shares)	75,486,000	75,023,000	74,679,000	67,971,000	60,830,000	59,024,000	58,891,000	58,728,000	73,403,000	58,944,000	58,538,000
Net income (loss) per share of common stock:
Basic (in usd per share)	$0.07	$0.01	$0.03	$0.04	$0.04	($0.01)	($0.06)	($0.16)	$0.14	($0.19)	($0.33)
Diluted (in usd per share)	$0.07	$0.01	$0.03	$0.04	$0.04	($0.01)	($0.06)	($0.16)	$0.13	($0.19)	($0.33)

NET_INCOME_LOSS_PER_SHARE_Narr

NET INCOME (LOSS) PER SHARE - Narrative (Details) (Stock options and restricted stock units)	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Stock options and restricted stock units
Schedule of Earnings Per Share [Line Items]
Total number of options to purchase common stock and restricted stock units, outstanding (in shares)	2.3	4.7	6.5

SUBSEQUENT_EVENT_Details

SUBSEQUENT EVENT (Details) (USD $)	1 Months Ended	12 Months Ended
In Thousands, except Share data in Millions, unless otherwise specified	Feb. 28, 2014	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Subsequent Event [Line Items]
Shares issued in connection with public offering, net of offering costs (in shares)	14.1
Proceeds from issuance of common stock, net	$31,700	$32,213	$576	$366

SUPPLEMENTARY_FINANCIAL_INFORM2

SUPPLEMENTARY FINANCIAL INFORMATION - Schedule of Selected Unaudited Financial Data for Each Quarter (Details) (USD $)	3 Months Ended								12 Months Ended
In Thousands, except Share data, unless otherwise specified	Dec. 31, 2014	Sep. 28, 2014	Jun. 29, 2014	Mar. 30, 2014	Dec. 31, 2013	Sep. 29, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Quarterly Financial Information Disclosure [Abstract]
Net revenue	$54,747	$38,430	$42,029	$43,198	$40,783	$33,840	$24,574	$20,237	$178,404	$119,434	$126,526
Gross margin	17,877	12,998	13,296	14,646	13,147	11,424	8,467	4,368	58,817	37,406	44,900
Income (loss) from operations	4,817	546	2,049	2,701	2,029	-230	-3,059	-9,753	10,113	-11,013	-19,284
Net income (loss)	$4,963	$537	$1,916	$2,465	$2,512	($412)	($3,567)	($9,508)	$9,881	($10,975)	($19,319)
Net income per share:
Basic (in usd per share)	$0.07	$0.01	$0.03	$0.04	$0.04	($0.01)	($0.06)	($0.16)	$0.14	($0.19)	($0.33)
Diluted (in usd per share)	$0.07	$0.01	$0.03	$0.04	$0.04	($0.01)	($0.06)	($0.16)	$0.13	($0.19)	($0.33)
Shares used in computing net income per share:
Basic (in shares)	73,861,000	73,731,000	73,532,000	66,275,000	59,127,000	59,024,000	58,891,000	58,728,000	71,897,000	58,944,000	58,538,000
Diluted (in shares)	75,486,000	75,023,000	74,679,000	67,971,000	60,830,000	59,024,000	58,891,000	58,728,000	73,403,000	58,944,000	58,538,000

SCHEDULE_II_VALUATION_AND_QUAL1

SCHEDULE II - VALUATION AND QUALIFYING ACCOUNTS - Allowance for Doubtful Accounts (Details) (Allowance for Doubtful Accounts, USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Allowance for Doubtful Accounts
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Year	$704	$541	$684
Charged (Credited) to Income	0	163	-143
Deduction and Other	-35	0	0
Balance at End of Year	$669	$704	$541