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Document And Entity Information - USD ($) $ in Millions	12 Months Ended
Document And Entity Information - USD ($) $ in Millions	Dec. 31, 2017	Mar. 12, 2018	Jun. 30, 2017
Document Information [Line Items]
Entity Registrant Name	PDF SOLUTIONS INC
Entity Central Index Key	0001120914
Trading Symbol	pdfs
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Well-known Seasoned Issuer	No
Entity Common Stock, Shares Outstanding (in shares)		32,295,144
Entity Public Float			$ 450
Document Type	10-K
Document Period End Date	Dec. 31, 2017
Document Fiscal Year Focus	2017
Document Fiscal Period Focus	FY
Amendment Flag	false

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 101,267	$ 116,787
Accounts receivable, net of allowances of $374 and $200, respectively	57,564	48,157
Prepaid expenses and other current assets	5,069	5,335
Total current assets	163,900	170,279
Property and equipment, net	25,386	19,341
Goodwill	1,923	215
Intangible assets, net	6,074	4,223
Deferred tax assets	16,348	15,640
Other non-current assets	10,545	12,631
Total assets	224,176	222,329
Current liabilities:
Accounts payable	2,536	2,206
Accrued compensation and related benefits	6,493	5,959
Accrued and other current liabilities	2,627	2,080
Deferred revenues - current portion	7,981	8,189
Billings in excess of recognized revenues		88
Total current liabilities	19,637	18,522
Long-term income taxes payable	3,902	3,354
Other non-current liabilities	2,269	1,650
Total liabilities	25,808	23,526
Commitments and contingencies (Note 5)
Stockholders’ equity:
Preferred stock, $0.00015 par value, 5,000 shares authorized, no shares issued and outstanding	0	0
Common stock, $0.00015 par value, 70,000 shares authorized; shares issued 39,799 and 38,514, respectively; shares outstanding 32,112 and 31,864, respectively	5	5
Additional paid-in capital	297,950	281,423
Treasury stock, at cost, 7,688 and 6,650 shares, respectively	(71,793)	(54,882)
Accumulated deficit	(27,089)	(25,752)
Accumulated other comprehensive loss	(705)	(1,991)
Total stockholders’ equity	198,368	198,803
Total liabilities and stockholders’ equity	$ 224,176	$ 222,329

Consolidated Balance Sheets (Parentheticals) - USD ($) shares in Thousands, $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Accounts receivable, allowance	$ 374	$ 200
Preferred stock, par value (in dollars per share)	$ 0.00015	$ 0.00015
Preferred stock, shares authorized (in shares)	5,000	5,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.00015	$ 0.00015
Common stock, shares authorized (in shares)	70,000	70,000
Common stock, shares issued (in shares)	39,799	38,514
Common stock, shares outstanding (in shares)	32,112	31,864
Treasury stock, shares (in shares)	7,688	6,650

Consolidated Statements of Operations and Comprehensive Income (Loss) - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Revenues:
Design-to-silicon-yield solutions	$ 74,436	$ 77,162	$ 63,839
Gainshare performance incentives	27,435	30,299	34,138
Total revenues	101,871	107,461	97,977
Cost of Design-to-silicon-yield solutions:
Direct costs of Design-to-silicon-yield solutions	47,050	44,074	38,847
Impairment of deferred cost
Amortization of acquired technology	471	374	176
Total cost of Design-to-silicon-yield solutions	47,521	44,448	39,023
Gross profit	54,350	63,013	58,954
Operating expenses:
Research and development	30,078	27,559	19,096
Selling, general and administrative	23,684	22,056	20,421
Amortization of other acquired intangible assets	398	432	196
Restructuring charges
Total operating expenses	54,160	50,047	39,713
Income from operations	190	12,966	19,241
Interest and other (expense) income, net	(264)	(10)	181
Income before taxes	(74)	12,956	19,422
Income tax provision (benefit)	1,263	3,853	7,015
Net income (loss)	$ (1,337)	$ 9,103	$ 12,407
Net income (loss) per share
Basic (in dollars per share)	$ (0.04)	$ 0.29	$ 0.39
Diluted (in dollars per share)	$ (0.04)	$ 0.28	$ 0.39
Weighted average common shares
Basic (in shares)	32,038	31,373	31,424
Diluted (in shares)	32,038	32,431	32,164
Net income (loss)	$ (1,337)	$ 9,103	$ 12,407
Other comprehensive (loss) income:
Foreign currency translation adjustments, net of tax	1,286	(448)	(862)
Comprehensive income (loss)	$ (51)	$ 8,655	$ 11,545

Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Common Stock [Member]	Additional Paid-in Capital [Member]	Treasury Stock [Member]	Retained Earnings [Member]	AOCI Attributable to Parent [Member]	Total
Balances (in shares) at Dec. 31, 2014	31,116		5,142
Balances at Dec. 31, 2014	$ 5	$ 248,734	$ (34,048)	$ (52,187)	$ (681)	$ 161,823
Issuance of common stock in connection with employee stock purchase plan (in shares)	110
Issuance of common stock in connection with employee stock purchase plan		1,379				$ 1,379
Issuance of common stock in connection with exercise of options (in shares)	655					655,000
Issuance of common stock in connection with exercise of options		5,039				$ 5,039
Vesting of restricted stock units (in shares)	453
Vesting of restricted stock units
Purchases of treasury stock in connection with tax withholdings on restricted stock grants (in shares)	(133)		133
Purchases of treasury stock in connection with tax withholdings on restricted stock grants			$ (1,810)			(1,810)
Repurchases of common stock (in shares)	(1,090)		1,090
Repurchases of common stock			$ (14,525)			(14,525)
Stock-based compensation expense		9,761				9,761
Tax benefit from employee stock plans		1,095				1,095
Comprehensive income				12,407	(862)	11,545
Balances (in shares) at Dec. 31, 2015	31,111		6,365
Balances at Dec. 31, 2015	$ 5	266,008	$ (50,383)	(39,780)	(1,543)	174,307
Issuance of common stock in connection with employee stock purchase plan (in shares)	173
Issuance of common stock in connection with employee stock purchase plan		1,557				$ 1,557
Issuance of common stock in connection with exercise of options (in shares)	393					393,000
Issuance of common stock in connection with exercise of options		2,972				$ 2,972
Vesting of restricted stock units (in shares)	336
Vesting of restricted stock units
Purchases of treasury stock in connection with tax withholdings on restricted stock grants (in shares)			136
Purchases of treasury stock in connection with tax withholdings on restricted stock grants			$ (2,317)			(2,317)
Repurchases of common stock (in shares)	(149)		149
Repurchases of common stock			$ (2,182)			(2,182)
Stock-based compensation expense		10,886				10,886
Tax benefit from employee stock plans
Comprehensive income				9,103	(448)	8,655
Cumulative-effect adjustment from adoption of ASU 2016-09 \| Accounting Standards Update 2016-09 [Member]				4,925		4,925
Balances (in shares) at Dec. 31, 2016	31,864		6,650
Balances at Dec. 31, 2016	$ 5	281,423	$ (54,882)	(25,752)	(1,991)	198,803
Issuance of common stock in connection with employee stock purchase plan (in shares)	200
Issuance of common stock in connection with employee stock purchase plan		1,864				$ 1,864
Issuance of common stock in connection with exercise of options (in shares)	440					440,000
Issuance of common stock in connection with exercise of options		2,823				$ 2,823
Vesting of restricted stock units (in shares)	450
Vesting of restricted stock units
Purchases of treasury stock in connection with tax withholdings on restricted stock grants (in shares)			196
Purchases of treasury stock in connection with tax withholdings on restricted stock grants			$ (3,493)			$ (3,493)
Repurchases of common stock (in shares)	(842)		842			842,182
Repurchases of common stock			$ (13,418)			$ (13,418)
Stock-based compensation expense		11,840				11,840
Tax benefit from employee stock plans
Comprehensive income				(1,337)	1,286	(51)
Balances (in shares) at Dec. 31, 2017	32,112		7,688
Balances at Dec. 31, 2017	$ 5	$ 297,950	$ (71,793)	$ (27,089)	$ (705)	$ 198,368

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Operating activities:
Net income (loss)	$ (1,337)	$ 9,103	$ 12,407
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	4,789	3,584	2,646
Stock-based compensation expense	11,810	11,002	9,756
Accrued contingent earn-out payments			500
Amortization of acquired intangible assets	869	805	372
Deferred taxes	(504)	216	1,563
Provision for (reversal of) doubtful accounts	174	(99)	(82)
Unrealized (gain) loss on foreign currency forward contract	(27)	(47)	12
Loss on disposal of assets	6	107	2
Tax benefit related to stock-based compensation expense			1,095
Excess tax benefit from stock-based compensation expense			(1,034)
Changes in operating assets and liabilities, net of acquisition effects:
Accounts receivable, net of allowances	(9,581)	(14,620)	4,373
Prepaid expenses and other current assets	373	(1,688)	(583)
Accounts payable	1,963	85	(684)
Accrued compensation and related benefits	249	1,178	(1,353)
Accrued and other liabilities	72	(231)	166
Deferred revenues	(326)	4,772	411
Billings in excess of recognized revenues	(88)	(1,179)	1,267
Other non-current assets	2,103	(10,988)	(498)
Net cash provided by operating activities	10,545	2,000	30,336
Investing activities:
Purchases of property and equipment	(10,255)	(11,282)	(4,784)
Purchases of intangible asset			(400)
Payments for business acquisitions, net of cash acquired	(3,841)		(5,152)
Net cash used in investing activities	(14,096)	(11,282)	(10,336)
Financing activities:
Payments of obligations assumed in business acquisition			(347)
Proceeds from exercise of stock options	2,822	2,972	5,039
Proceeds from employee stock purchase plan	1,865	1,557	1,379
Repurchases of common stock	(13,418)	(2,182)	(14,525)
Excess tax benefit from stock-based compensation expense			1,034
Payments for taxes related to net share settlement of equity awards	(3,493)	(2,317)	(1,810)
Net cash (used in) provided by financing activities	(12,224)	30	(9,230)
Effect of exchange rate changes on cash and cash equivalents	255	(119)	(76)
Net (decrease) increase in cash and cash equivalents	(15,520)	(9,371)	10,694
Cash and cash equivalents, beginning of year	116,787	126,158	115,464
Cash and cash equivalents, end of year	101,267	116,787	126,158
Supplemental disclosure of cash flow information:
Taxes	2,244	3,635	4,983
Interest			16
Property and equipment received and accrued in accounts payable and accrued and other liabilities	$ 1,235	$ 666	$ 212

Note 1 - Business and Significant Accounting Policies

12 Months Ended

Dec. 31, 2017

Notes to Financial Statements

Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block]

Business and Significant Accounting Policies

PDF Solutions, Inc. (the “Company” or “PDF”), provides infrastructure technologies and services to improve yield and optimize performance of integrated circuits. The Company

’s approach includes manufacturing simulation and analysis, combined with yield improvement methodologies to increase product yield and performance.

Basis of Presentation

— The consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries after the elimination of all significant intercompany balances and transactions.

Use of Estimates

— The preparation of financial statements in conformity with generally accepted accounting principles in the United States (“U.S. GAAP”) requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Significant estimates in these financial statements include revenue recognition for fixed-price solution implementation service contracts, stock-based compensation expense and accounting for income taxes. Actual results could differ from those estimates.

Concentration of Credit Risk

— Financial instruments that potentially expose the Company to concentrations of credit risk consist primarily of cash and cash equivalents and accounts receivable. The Company maintains its cash and cash equivalents with what it considers high credit quality financial institutions.

The Company primarily sells its technologies and services to companies in Asia, Europe and North America within the semiconductor industry.

As of

December

31,

2017,

three

customers accounted for

57%

of the Company’s gross accounts receivable and

one

customer accounted for

40%

of the Company’s revenues for

2017.

As of

December

31,

2016,

two

customers accounted for

55%

of the Company’s gross accounts receivable and

two

customers accounted for

52%

of the Company’s revenues for

2016.

See Note

for further details. The Company does

not

require collateral or other security to support accounts receivable. To reduce credit risk, management performs ongoing credit evaluations of its customers’ financial condition. The Company maintains allowances for potential credit losses. The allowance for doubtful accounts, which was based on management’s best estimates, could be adjusted in the near term from current estimates depending on actual experience. Such adjustments could be material to the consolidated financial statements.

Cash, Cash Equivalents

and Short-term Investments

— The Company considers all highly liquid investments with an original maturity of

days or less to be cash equivalents. Investments with original maturities greater than

three

months and less than

one

year are classified as short-term investments.

Property and Equipment

— Property and equipment are stated at cost and are depreciated using the straight-line method over the estimated useful lives of the related asset as follows:

Computer equipment (years)		3
Software (years)		3
Furniture, fixtures, and equipment (years)	5	-	7
Leasehold improvements	Shorter of estimated useful life or term of lease

Long-lived Assets

— The Company’s long-lived assets, excluding goodwill, consist of property and equipment and intangible assets. The Company periodically reviews its long-lived assets for impairment

For assets to be held and used, the Company initiates its review whenever events or changes in circumstances indicate that the carrying amount of a long-lived asset group

may

not

be recoverable. Recoverability of an asset group is measured by comparison of its carrying amount to the expected future undiscounted cash flows that the asset group is expected to generate. If it is determined that an asset group is

not

recoverable, an impairment loss is recorded in the amount by which the carrying amount of the asset group exceeds its fair value.

Goodwill

— The Company records goodwill when the purchase consideration of an acquisition exceeds the fair value of the net tangible and identified intangible assets as of the date of acquisition. The Company performs an annual impairment assessment of its goodwill during the

fourth

quarter of each calendar year or more frequently if required to determine if any events or circumstances exist, such as an adverse change in business climate or a decline in the overall industry demand, that would indicate that it would more likely than

not

reduce the fair value of a reporting unit below its carrying amount, including goodwill. If events or circumstances do

not

indicate that the fair value of a reporting unit is below its carrying amount, then goodwill is

not

considered to be impaired and

further testing is required. If further testing is required, the Company performs a

two

-step process. The

first

step involves comparing the fair value of its reporting unit to its carrying value, including goodwill. If the carrying value of the reporting unit exceeds its fair value, the

second

step of the test is performed by comparing the carrying value of the goodwill in the reporting unit to its implied fair value. An impairment charge is recognized for the excess of the carrying value of goodwill over its implied fair value. For the purpose of impairment testing, the Company has determined that it has

one

reporting unit. There has been

impairment of goodwill for any periods presented.

Revenue Recognition

— The Company derives revenue from

two

sources: Design-to-silicon-yield solutions and Gainshare performance incentives.

Design-to-silicon-yield solutions

— Revenues that are derived from Design-to-silicon-yield solutions come from services and software and hardware licenses. The Company recognizes revenue for each element of Design-to-silicon-yield solutions as follows:

The Company generates a significant portion of its Design-to-silicon-yield solutions revenue from fixed-price solution implementation service contracts delivered over a specific period of time. These contracts require reliable estimation of costs to perform obligations and the overall scope of each engagement. Revenue under project

–based contracts for solution implementation services is recognized as services are performed using percentage of completion method of contract accounting based on costs or labor-hours input method, whichever is the most appropriate measure of the progress towards completion of the contract. Losses on fixed-price solution implementation contracts are recognized in the period when they become probable. Revisions in profit estimates are reflected in the period in which the conditions that require the revisions become known and can be estimated (cumulative catch-up method). During the year ended

December 31, 2017,

the Company recognized changes in

two

of its project’s profitability from revisions in estimates due to the scope changes that resulted in unfavorable changes of net income of

$1.2

million or

$0.04

per diluted share

. During the year ended

December 31, 2016,

the Company recognized changes in

one

of its project

’s profitability from revisions in estimates due to the scope changes that resulted in favorable changes of net income of

$0.9

million or

$0.03

per diluted share.

Revenue under time and materials contracts for solution implementation services are recognized as the services are performed.

On occasion, the Company licenses its software products as a component of its fixed-price service contracts. In such instances, the software products are licensed to customers over a specified term of the agreement with support and maintenance to be provided, if applicable, over the license term. The amount of product and service revenue recognized in a given period is affected by the Company

’s judgment as to whether an arrangement includes multiple deliverables and, if so, the Company’s determination of the fair value of each deliverable. In general, vendor-specific objective evidence of selling price (“VSOE”) does

not

exist for the Company’s solution implementation services and software products and because the Company’s services and products include our unique technology, the Company is

not

able to determine

third

-party evidence of selling price (“TPE”). Therefore, in such circumstances the Company uses best estimated selling prices (“BESP”) in the allocation of arrangement consideration. In determining BESP, the Company applies significant judgment as the Company’s weighs a variety of factors, based on the facts and circumstances of the arrangement. The Company typically arrives at BESP for a product or service that is

not

sold separately by considering company-specific factors such as geographies, internal costs, gross margin objectives, pricing practices used to establish bundled pricing, and existing portfolio pricing and discounting. After fair value is established for each deliverable, the total transaction amount is allocated to each deliverable based upon its relative selling price. Fees allocated to solution implementation services are recognized using the percentage of completion method of contract accounting. Fees allocated to software and related support and maintenance are recognized under software revenue recognition guidance.

In some instances, the Company also licenses its D

esign-For-Inspection (“DFI”) system as a separate component of fixed-price service contracts. The Company allocates revenue to all deliverables based on their relative selling prices. The Company currently does

not

have VSOE for its DFI system, thus the Company uses either TPE or BESP in the allocation of arrangement consideration.

The Company defers certain pre-contract costs incurred for specific anticipated contracts. Deferred costs consist primarily of direct costs to provide solution implementation services in relation to the specific anticipated contracts. The Company recognizes such costs as a component of cost of revenues, the timing of which is dependent upon persuasive evidence of contract arrangement assuming all other revenue recognition criteria are met. The Company also defers costs from arrangements that required us to defer the revenues, typically due to revenue recognition from multi-element arrangements or from contracts subject to customer acceptance. These costs are recognized in proportion to the related revenue. At the end of the reporting period, the Company evaluates its deferred costs for their probable recoverability. The Company recognizes impairment of deferred costs when it is determined that the costs

longer have future benefits and are

longer recoverable. Deferred costs balance

was

$0.6

million and

$0.5

million as of

December 31, 2017

and

December 31, 2016,

respectively. The balance was included in prepaid expenses and other current assets and other non-current assets in the accompanying consolidated balance sheets.

The Company also licenses its software products separately from solution implementations. For software license arrangements that do

not

require significant modification or customization of the underlying software, software license revenue is recognized under the residual method when (l) persuasive evidence of an arrangement exists, (

) delivery has occurred, (

) the fee is fixed or determinable, (

) collectability is probable, and (

) the arrangement does

not

require services that are essential to the functionality of the software. When arrangements include multiple elements such as support and maintenance, consulting (other than for fixed price solution implementations), installation, and training, revenue is allocated to each element of a transaction based upon its fair value as determined by the Company's VSOE and such services are recorded as services revenue. VSOE for maintenance is generally established based upon negotiated renewal rates while VSOE for consulting, installation, and training services is established based upon the Company's customary pricing for such services when sold separately. When software is licensed for a specified term, fees for support and maintenance are generally bundled with the license fee over the entire term of the contract. The Company is unable to establish VSOE of fair value for maintenance services that are generally bundled with term licenses. In these cases, the Company recognizes revenue ratably over the term of the contract. For multiple-element arrangements containing non-software services, the Company: (

) determines whether each element constitutes a separate unit of accounting; (

) determines the fair value of each element using the selling price hierarchy of VSOE, TPE or BESP, as applicable; and (

) allocates the total price to each separate unit of accounting based on the relative selling price method. An element constitutes a separate unit of accounting when the delivered item has standalone value and delivery of the undelivered element is probable and within our control. For multiple-element arrangements that contain both software and non-software elements, the Company allocates revenue to software or software-related elements as a group and any non-software elements separately based on the selling price hierarchy of VSOE, TPE or BESP. Once revenue is allocated to software or software-related elements as a group, we recognize revenue in conformance with software revenue accounting guidance. Revenue is recognized when revenue recognition criteria are met for each element.

Revenue from software-as-a-service (SaaS) that allow for the use of a hosted software product or service over a contractually determined period of time without taking possession of software are accounted for as subscriptions and recognized as revenue ratably over the coverage period beginning on the date the service is made available to customers. Revenue for software licenses with extended payment terms is

not

recognized in excess of amounts due. For software license arrangements that require significant modification or customization of the underlying software, the software license revenue is recognized as services are performed using the percentage of completion method of contract accounting, and such revenue is recorded as services revenue.

Deferred revenues consist substantially of amounts invoiced in advance of revenue recognition and is recognized as the revenue recognition criteria are met. Deferred revenues that will be recognized during the succeeding

month period is recorded as current deferred revenues and the remaining portion is recorded as non- current deferred revenues. Non-current portion of deferred revenue was

$1.5

million and

$1.5

million respectively as of

December 31, 2017

and

2016.

This balance was recorded in the other non-current liabilities in the accompanying consolidated balance sheets.

Gainshare Performance Incentives

— When the Company enters into a contract to provide yield improvement services, the contract usually includes

two

components: (

) a fixed fee for performance by the Company of services delivered over a specific period of time; and (

) a Gainshare performance incentive component where the customer

may

pay a contingent variable fee, usually after the fixed fee period has ended. Revenue derived from Gainshare performance incentives represents profit sharing and performance incentives earned contingent upon the Company’s customers reaching certain defined operational levels established in related solution implementation service contracts. Gainshare performance incentives periods are usually subsequent to the delivery of all contractual services and therefore have virtually

cost to the Company. Due to the uncertainties surrounding attainment of such operational levels, the Company recognizes Gainshare performance incentives revenue (to the extent of completion of the related solution implementation contract) upon receipt of performance reports or other related information from the customer supporting the determination of amounts and probability of collection.

Accounts Receivable

— Accounts receivable include amounts that are unbilled at the end of the period that are expected to be billed and collected within

-month period. Unbilled accounts receivable are determined on an individual contract basis. Unbilled accounts receivable, included in accounts receivable, totaled

$22.2

million and

$20.8

million as of

December 31, 2017,

and

December 31, 2016,

respectively. Unbilled accounts receivable that are

not

expected to be billed and collected during the succeeding

-month period are recorded in other non-current assets and totaled

$8.6

million and

$9.8

million as of

December 31, 2017

and

2016,

respectively. The Company performs ongoing credit evaluations of its customers’ financial condition. An allowance for doubtful accounts is maintained for probable credit losses based upon the Company’s assessment of the expected collectability of the accounts receivable. The allowance for doubtful accounts is reviewed on a quarterly basis to assess the adequacy of the allowance.

Allowance for doubtful accounts are summarized below:

	Balance at Beginning of Period		Charged to Costs and Expenses		Deductions/ Write-offs of Accounts		Balance at End of Period
Allowance for doubtful accounts
201 7	$	200	$	174	$	—	$	374
201 6	$	299	$	—	$	99	$	200
201 5	$	381	$	—	$	82	$	299

Software Development Costs

— Internally developed software includes software developed to meet our internal needs to provide solution implementation services to our end-customers. These capitalized costs consist of internal compensation related costs and external direct costs incurred during the application development stage and are amortized over their useful lives, generally

six

years. The costs to develop software that is marketed externally have

not

been capitalized as we believe our current software development process is essentially completed concurrent with the establishment of technological feasibility. As such, all related software development costs are expensed as incurred and included in research and development expense in our consolidated statements of operations.

Research and Development

—

Research and development expenses consist primarily of personnel-related costs to support product development activities, including compensation and benefits, outside development services, travel, facilities cost allocations, and stock-based compensation charges.

Research and development expenses are charged to operations as incurred.

Stock-Based Compensation

— Stock-based compensation is estimated at the grant date based on the award’s fair value and is recognized on a straight-line basis over the vesting periods, generally

four

years. The Company has elected to use the Black-Scholes-Merton option-pricing model, which incorporates various assumptions including volatility, expected life and interest rates. The expected volatility is based on the historical volatility of the Company’s common stock over the most recent period commensurate with the estimated expected life of the Company’s stock options. The expected life of an award is based on historical experience and on the terms and conditions of the stock awards granted to employees. The interest rate assumption is based upon observed Treasury yield curve rates appropriate for the expected life of the Company’s stock options.

As stock-based compensation expense recognized is based on awards ultimately expected to vest, it has been reduced for estimated forfeitures. Forfeitures are estimated at the time of grant and revised, if necessary, in subsequent periods if actual forfeitures differ from those estimates.

Income Taxes

– The Company's provision for income tax comprises its current tax liability and change in deferred tax assets and liabilities. Deferred tax assets and liabilities are recognized for the expected tax consequences of temporary differences between the tax bases of assets and liabilities. The measurement of current and deferred tax assets and liabilities is based on provisions of enacted tax laws; the effect of future changes in tax laws or rates are

not

anticipated. Valuation allowances are provided to reduce deferred tax assets to an amount that in management’s judgment is more likely than

not

to be recoverable against future taxable income.

U.S. taxes are provided on earnings of non-U.S. subsidiaries, to the extent such earnings are deemed to be permanently invested. The Company's income tax calculations are based on application of the respective U.S. federal, state or foreign tax laws. The Company’s tax filings, however, are subject to audit by the respective tax authorities. Accordingly, the Company recognizes tax liabilities based upon its estimate of whether, and the extent to which, additional taxes will be due when such estimates are more-likely-than-

not

to be sustained. An uncertain income tax position will

not

be recognized if it has less than a

50%

likelihood of being sustained. To the extent the final tax liabilities are different than the amounts originally accrued, the increases or decreases are recorded as income tax expense or benefit in the consolidated statements of operations.

Net Income Per Share

–

Basic net income per share is computed by dividing net income by weighted average number of common shares outstanding for the period (excluding outstanding stock options and shares subject to repurchase). Diluted net income per share is computed using the weighted-average number of common shares outstanding for the period plus the potential effect of dilutive securities which are convertible into common shares (using the treasury stock method), except in cases in which the effect would be anti-dilutive. Dilutive potential common shares consist of incremental common shares issuable upon exercise of stock options, upon vesting of restricted stock units, contingently issuable shares for all periods and assumed issuance of shares under employee stock purchase plan.

dilutive potential common shares are included in the computation of any diluted per share amount when a loss from continuing operations was reported by the Company.

Foreign Currency Translation

— The functional currency of the Company’s foreign subsidiaries is the local currency for the respective subsidiary. The assets and liabilities are translated at the period-end exchange rate, and statements of operations are translated at the average exchange rate during the year. Gains and losses resulting from foreign currency translations are included as a component of other comprehensive income (loss). Gains and losses resulting from foreign currency transactions are included in the consolidated statements of operations and comprehensive income.

Derivative Financial Instruments

— The Company operates internationally and is exposed to potentially adverse movements in foreign currency exchange rates. The Company enters into foreign currency forwards contracts to reduce the exposure to foreign currency exchange rate fluctuations on certain foreign currency denominated monetary assets and liabilities. The Company does

not

use foreign currency contracts for speculative or trading purposes. The Company records these forward contracts at fair value. The counterparty to these foreign currency forward contracts is a large global financial institution that the Company believes is creditworthy, and therefore, we believe the credit risk of counterparty non-performance is

not

significant. These foreign currency forward contracts are

not

designated for hedge accounting treatment. Therefore, the change in fair value of these derivatives is recorded into earnings as a component of interest and other income (expense), net and offsets the change in fair value of the foreign currency denominated monetary assets and liabilities, which are also recorded in interest and other income (expense), net. The duration of these forward contracts is usually between

two

three

months.

Litigation

— From time to time, the Company is subject to various claims and legal proceedings that arise in the ordinary course of business. The Company accrues for losses related to litigation when a potential loss is probable and the loss can be reasonably estimated in accordance with Financial Accounting Standard Board ("FASB") requirements. As of

December 31, 2017,

the Company is

not

a party to any material legal proceedings, thus

loss was probable and

amount was accrued.

Recent Accounting Pronouncements

—

May 2014,

the FASB issued ASU

No.

2014

09,

Revenue from Contracts with Customers (Topic

606

), which supersedes the revenue recognition requirements in “Revenue Recognition (Topic

605

).” Subsequently, the FASB has issued several amendments to the standard, including clarification on accounting for licenses of intellectual property and identifying performance obligations

Under Topic

606,

the new revenue recognition standard provides a

five

-step analysis of transactions to determine when and how revenue is recognized. The core principle is that a company should recognize revenue to reflect the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. This new standard is effective for annual periods beginning after

December 15, 2017,

including interim periods within that reporting period

In addition, the standard requires

enhanced disclosure of the nature, amount, timing, and uncertainty of revenue and cash flows arising from contracts with customers.

The guidance permits

two

methods of adoption: retrospectively to each prior reporting period presented (full retrospective method), or retrospectively with the cumulative effect of initially applying the guidance recognized at the date of initial application (modified retrospective method)

Topic

606

is effective for us beginning with the

first

quarter of fiscal

2018.

We chose to adopt the standard using the modified retrospective transition method

. The use of the modified retrospective transition method requires us to evaluate only contracts that were in effect at the beginning of fiscal

2018

as if

those contracts had been accounted for under Topic

606

from the beginning of their terms. Upon adoption, we will recognize the cumulative effect of adopting this guidance as an adjustment to retained earnings on the date of initial application. Prior periods will

not

be retrospectively adjusted.

In preparation for adoption of the standard,

we are implementing changes to policies, processes and controls related to revenue recognition

. We do

not

expect any major change in our financial systems.

While the Company

’s adoption and evaluation of the impact of this new guidance is

not

complete, we believe the impact of the new standard related to revenue recognition will have a material impact on our consolidated financial statements, due to the change in the timing of revenue recognition for certain products to be earlier than under current revenue recognition guidance.

Generally

, we expect revenue generated under Topic

606

to be recognized earlier than revenue would have been under Topic

605,

both upon adoption and quarterly the foreseeable future. Upon adoption of Topic

606,

this accounting treatment will result in some of our existing deferred revenue and backlog at the beginning of fiscal

2018

being reduced with a corresponding adjustment to retained earnings.

The adoption of Topic

606

will impact our accounting for certain commercial

software multi-element arrangements (“MEA”) that combine software-related deliverables, which

may

include software contracts with varying terms and service elements. Topic

605

requires VSOE to recognize revenue separately for each of the different elements. Topic

606

requires us to separate the different performance obligation through the use of stand-alone selling prices (“SSPs”) and to recognize the revenue allocated to the different performance obligation as if those performance obligation had been sold on a standalone basis, either up front or over time. The most significant impact of this change relates to our accounting for term based software license revenue. For our Exensio software in particular, we will recognize a portion of revenue at the time of delivery rather than ratably over the term of the license.

More judgments and estimates are required under Topic

606

than are required under Topic

605,

including estimating the SSP for each performance obligation identified within our

arrangements with multiple elements and estimating the amount of variable consideration within our Integrated Yield Ramp (or IYR) engagements that include a Gainshare element. Due to the complexity of certain of our commercial contracts that include contingent variable fees, the actual revenue recognition treatment required under Topic

606

will depend on contract-specific terms and, in some instances,

may

vary from the recognition required under Topic

605.

may

have to estimate revenue related to contingent variable fees or usage-based or sales-based royalties prior to the receipt of performance reports, such as Gainshare acknowledgements, or other related information from customers. Revenue recognition related to other professional services will remain substantially unchanged.

Topic

606

also requires the deferral of incremental costs of obtaining a contract with a customer. This requires that we capitalize commission costs that are directly related to obtaining customer contracts and amortize them over the period the assets are expected to contribute future cash flows. As

our commission rates paid for renewals are commensurate with the rates paid for initial contracts, we will recognize the deferred direct costs over the contract term.

The modified retrospective transition approach allows us to avoid restating comparative years, however in

2018,

the year of adoption, we are required to provide additoinal disclosure for the amount by which each financial statement line item is affected as a result of applying Topic

606

(as compared to Topic

605

)

February 2016,

the Financial Accounting Standards Board (or FASB) issued ASU

No.

2016

02,

Leases (Topic

842

). The update requires that most leases, including operating leases, be recorded on the balance sheet as an asset and a liability, initially measured at the present value of the lease payments. Subsequently, the lease asset will be amortized generally on a straight-line basis over the lease term, and the lease liability will bear interest expense and be reduced for lease payments. The amendments in this update are effective for public companies

’ financial statements issued for fiscal years beginning after

December 15, 2018,

including interim periods within those fiscal years. The Company is still in the process of evaluating the impact of adopting this new accounting standard on its consolidated financial statements and footnote disclosures.

August 2016,

the FASB issued ASU

No.

2016

15,

Classification of Certain Cash Receipts and Cash Payments. The purpose of this standard is to clarify the treatment of several cash flow categories. This update is effective for annual periods beginning after

December 15, 2017,

and interim periods within those fiscal years. The adoption of this standard is

not

expected to have a material impact on our financial statements and footnote disclosures.

November 2016,

the FASB issued ASU

No.

2016

18,

Restricted Cash, that will require that the amounts generally described as restricted cash and restricted cash equivalents would be included with cash and cash equivalents when reconciling the beginning-of-period and end-of-period amounts shown on the statement of cash flows. The new guidance also requires certain disclosures to supplement the statement of cash flows. The guidance becomes effective for the Company for the year ending on

December 31, 2018,

though early adoption is permitted. The Company is currently evaluating the impact of adopting this new guidance on its consolidated financial statements.

January 2017,

the FASB issued ASU

No.

2017

01,

Business Combinations: Clarifying the Definition of a Business, which narrows the existing definition of a business and provides a framework for evaluating whether a transaction should be accounted for as an acquisition (or disposal) of assets or a business. The guidance is effective for fiscal years beginning after

December 15, 2017.

The Company does

not

anticipate that the adoption of this standard will have a significant impact on our consolidated financial statements or the related disclosures.

January 2017,

the FASB issued ASU

No.

2017

04,

Intangibles - Goodwill and Other (Topic

350

) (“ASU

No.

2017

04”

). ASU

No.

2017

eliminates step

from the annual goodwill impairment test. This update is effective for annual periods beginning after

December 15, 2019,

and interim periods within those fiscal years, with early adoption permitted, and is to be applied on a prospective basis. The Company does

not

anticipate that the adoption of this standard will have a significant impact on our consolidated financial statements or the related disclosures.

May 2017,

the FASB issued ASU

No.

2017

09,

Compensation-Stock Compensation (Topic

718

) Scope of Modification Accounting (“ASU

No.

2017

09”

). ASU

No.

2017

clarifies which changes to the terms or conditions of a share-based payment award require an entity to apply modification accounting in Topic

718.

The standard is effective for interim and annual reporting periods beginning after

December 15, 2017.

The adoption of this standard will impact modifications that happen after the adoption date.

February 2018,

the FASB issued ASU

No.

2018

02,

Income Statement – Reporting Comprehensive Income Topic

220

): Reclassification of Certain Tax Effect from Accumulated Other Comprehensive Income. This update allows a reclassification from accumulated other comprehensive income to retained earnings for stranded tax effects resulting from the Tax Cuts and Job Act enacted in

December 2017.

This update will be effective for the Company for fiscal years beginning after

December 15, 2018

and interim periods within those fiscal years. Early adoption is permitted.

The Company does

not

anticipate that the adoption of this standard will have a significant impact on our consolidated financial statements or the related disclosures.

Note 2 - Property and Equipment

12 Months Ended

Dec. 31, 2017

Notes to Financial Statements

Property, Plant and Equipment Disclosure [Text Block]

Property and Equipment

Property and equipment consist of (in thousands):

	December 31,
	201 7			201 6
Computer equipment	$	10,729		$	10,642
Software		3,348			1,679
Furniture, fixtures, and equipment		3,676			1,185
Leasehold improvements		1,980			1,132
Test equipment		13,796			11,723
Construction-in-progress		12,527			9,550
		46,056			35,911
Accumulated depreciation		(20,670	)		(16,570	)
Total	$	25,386		$	19,341

Test equipment includes DFI assets

at customer sites that are contributing to DFI solution revenues. The construction-in-progress balance related to construction of DFI assets totaled

$10.9

million and

$8.0

million as of

December 31, 2017

and

December 31, 2016,

respectively. Depreciation and amortization expense for years ended

December 31, 2017,

2016,

and

2015

was

$4.8

million,

$3.6

million and

$2.6

million, respectively.

Note 3 - Business Combination

12 Months Ended

Dec. 31, 2017

Notes to Financial Statements

Business Combination Disclosure [Text Block]

Business Combination

July 11, 2017 (

the "Acquisition Date"), the Company

acquired certain assets from Realtime Performance Europe B.V. (formerly doing business as Kinesys Software). Pursuant to the terms of an asset purchase agreement, the Company acquired the ALPS and GEMbox software products and certain related liabilities for the purpose of adding device traceability and process data collection through assembly and test to the software products it licenses.

The total purchase price was

$4.3

million, of which

$0.5

million was classified and recorded as the fair value of the contingent consideration on the balance sheet as of Acquisition Date. The Company

may

pay the contingent consideration through

July 11, 2019,

with a maximum potential payment amount of up to

$0.6

million, depending on the completion of certain milestones related to the integration of the ALPS software into the Company's Exensio platform and licenses thereof. The fair value of the contingent consideration liability was determined as of the Acquisition Date using unobservable inputs

, which are remeasured at each reporting date until settlement.

These inputs include the probability of meeting the milestones related to the integration and license of the ALPS software and a risk-adjusted discount rate to adjust the probability-weighted cash flows to present value.

The Company accounted for this acquisition as a business combination. This method requires that assets acquired and liabilities assumed in a business combination be recognized at their fair values as of the Acquisition Date. The excess of purchase consideration over the fair value of net tangible and identifiable intangible assets acquired was recorded as goodwill. The goodwill recorded from this acquisition represents business benefits the Company anticipates realizing from optimizing resources and new and expanded sales opportunities that extend the Company's footprint throughout the entire systems value chain. The amount of goodwill expected to be deductible for tax purposes is

$1.7

million. Pro forma results of operations have

not

been presented because the effect of the acquisition was

not

material to our financial results.

Intangible assets consist of developed technology, customer relationships, and trademarks. The value assigned to intangibles are based on estimates and judgments regarding expectations for success and life cycle of intangibles acquired.

The following table summarizes the allocation of the fair values of the assets acquired and liabilities assumed and the related useful lives, where applicable:

	(in thousand)			Amortization period (years)


Finite-lived intangible assets :
Developed technology	$	1,720			9
Customer relationship		820			9
Tradename		180			7
Deferred revenue		(190	)
Other receivables		53
Net asset acquired	$	2,583
Goodwill		1,708
Purchase consideration	$	4,291

Note 4 - Goodwill and Intangible Assets

12 Months Ended

Dec. 31, 2017

Notes to Financial Statements

Goodwill and Intangible Assets Disclosure [Text Block]

. Goodwill and Intangible Assets

As of both

December 31, 2017,

and

December 31, 2016,

the carrying amount of goodwill was

$1.9

million. The following is a rollforward of the Company's goodwill balance (in thousands):

	December 31, 201 7
Balance as of December 31, 201 6	$	215
Add: Goodwill from acquisition		1,708
Goodwill adjustment		-
Balance as of December 31, 201 7	$	1,923

Intangible assets balance

was

$6.1

million and

$4.2

million as of

December 31, 2017,

and

December 31, 2016,

respectively. Intangible assets as of

December 31, 2016,

consist of the following (in thousands):

				December 31, 201 7							Decemb er 31, 201 6
	Amortization Period (Years)			Gross Carrying Amount		Accumulated Amortization			Net Carrying Amount		Gross Carrying Amount		Accumulated Amortization			Net Carrying Amount
Acquired identifiable intangibles:

Customer relationships	1	-	9	$	6,740	$	(4,145	)	$	2,595	$	5,920	$	(3,825	)	$	2,095
Developed technology	4	-	6		15,820		(12,829	)		2,991		14,100		(12,359	)		1,741
Tradename	2	-	4		790		(622	)		168		610		(583	)		27
Backlog		1			100		(100	)		-		100		(100	)		-
Patent	7	-	10		1,800		(1,480	)		320		1,800		(1,440	)		360
Other acquired intangibles		4			255		(255	)		-		255		(255	)		-
Total				$	25,505	$	(19,431	)	$	6,074	$	22,785	$	(18,562	)	$	4,223

The weighted average amortization period for acquired identifiable intangible assets

was

6.74

years as of

December 31, 2017.

Intangible asset amortization expense for years ended

December 31, 2017,

2016,

and

2015

was

$0.9

million,

$0.8

million and

$0.4

million, respectively. The Company expects annual amortization of acquired identifiable intangible assets to be as follows (in thousands):

Year Ending December 31,
201 8	$	1,009
201 9		1,009
20 20		1,009
202 1		833
202 2		626
202 3 and thereafter		1,588
Total future amortization expense	$	6,074

Intangible assets are amortized over their useful lives unless these lives are determined to be indefinite. Intangible assets are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset or asset group

may

not

be recoverable. During year ended

December 31,

201

there were

indicators of impairment related to the Company’s intangible assets.

- Definition

The entire disclosure for the aggregate amount of goodwill and a description of intangible assets, which may include (a) for amortizable intangible assets (also referred to as finite-lived intangible assets), the carrying amount, the amount of any significant residual value, and the weighted-average amortization period, (b) for intangible assets not subject to amortization (also referred to as indefinite-lived intangible assets), the carrying amount, and (c) the amount of research and development assets acquired and written off in the period, including the line item in the income statement in which the amounts written off are aggregated, if not readily apparent from the income statement. Also discloses (a) for amortizable intangibles assets in total and by major class, the gross carrying amount and accumulated amortization, the total amortization expense for the period, and the estimated aggregate amortization expense for each of the five succeeding fiscal years, (b) for intangible assets not subject to amortization the carrying amount in total and by major class, and (c) for goodwill, in total and for each reportable segment, the changes in the carrying amount of goodwill during the period (including the aggregate amount of goodwill acquired, the aggregate amount of impairment losses recognized, and the amount of goodwill included in the gain (loss) on disposal of a reporting unit). If any part of goodwill has not been allocated to a reportable segment, discloses the unallocated amount and the reasons for not allocating. For each impairment loss recognized related to an intangible asset (excluding goodwill), discloses: (a) a description of the impaired intangible asset and the facts and circumstances leading to the impairment, (b) the amount of the impairment loss and the method for determining fair value, (c) the caption in the income statement or the statement of activities in which the impairment loss is aggregated, and (d) the segment in which the impaired intangible asset is reported. For each goodwill impairment loss recognized, discloses: (a) a description of the facts and circumstances leading to the impairment, (b) the amount of the impairment loss and the method of determining the fair value of the associated reporting unit, and (c) if a recognized impairment loss is an estimate not finalized and the reasons why the estimate is not final. May also disclose the nature and amount of any significant adjustments made to a previous estimate of an impairment loss.

+ References + Details

Note 5 - Commitments and Contingencies

12 Months Ended

Dec. 31, 2017

Notes to Financial Statements

Commitments and Contingencies Disclosure [Text Block]

. Commitments and Contingencies

Leases

— The Company leases administrative and sales offices and certain equipment under noncancelable operating leases, which contain various renewal options and, in some cases, require payment of common area costs, taxes and utilities. These operating leases expire at various times through

2024.

Rent expense was

$2.3

million,

$2.2

million and

$2.1

million in

2017,

2016,

and

2015,

respectively.

Future minimum lease payments under noncancelable operating leases at

December 31,

201

are as follows (in thousands):

Year Ending December 31,
201 8	$	1,767
201 9		535
20 20		445
202 1		361
202 2		101
202 3 and thereafter		26
Total future minimum lease payments	$	3,235

Indemnifications

— The Company generally provides a warranty to its customers that its software will perform substantially in accordance with documented specifications typically for a period of

days following delivery of its products. The Company also indemnifies certain customers from

third

-party claims of intellectual property infringement relating to the use of its products. Historically, costs related to these guarantees have

not

been significant. The Company is unable to estimate the maximum potential impact of these guarantees on its future results of operations.

Purchase obligations

— The Company has purchase obligations with certain suppliers for the purchase of goods and services entered in the ordinary course of business. As of

December 31, 2017,

total outstanding purchase obligations were

$9.5

million, which are primarily due within the next

months.

Indemnification of Officers and Directors

— As permitted by the Delaware general corporation law, the Company has included a provision in its certificate of incorporation to eliminate the personal liability of its officers and directors for monetary damages for breach or alleged breach of their fiduciary duties as officers or directors, other than in cases of fraud or other willful misconduct.

In addition, the Bylaws of the Company provide that the Company is required to indemnify its officers and directors even when indemnification would otherwise be discretionary, and the Company is required to advance expenses to its officers and directors as incurred in connection with proceedings against them for which they

may

be indemnified. The Company has entered into indemnification agreements with its officers and directors containing provisions that are in some respects broader than the specific indemnification provisions contained in the Delaware general corporation law. The indemnification agreements require the Company to indemnify its officers and directors against liabilities that

may

arise by reason of their status or service as officers and directors other than for liabilities arising from willful misconduct of a culpable nature, to advance their expenses incurred as a result of any proceeding against them as to which they could be indemnified, and to obtain directors

’ and officers’ insurance if available on reasonable terms. The Company has obtained directors’ and officers’ liability insurance in amounts comparable to other companies of the Company’s size and in the Company’s industry. Since a maximum obligation of the Company is

not

explicitly stated in the Company’s Bylaws or in its indemnification agreements and will depend on the facts and circumstances that arise out of any future claims, the overall maximum amount of the obligations cannot be reasonably estimated.

Litigation

December 31, 2017,

the Company was

not

party to any material legal proceedings, thus

loss was probable and

amount was accrued.

Note 6 - Stockholders' Equity

12 Months Ended

Dec. 31, 2017

Notes to Financial Statements

Shareholders' Equity and Share-based Payments [Text Block]

. Stockholders’ Equity

Stock-based compensation expenses related to the Company

’s employee stock purchase plan and stock plans were allocated as follows (in thousands):

	Years Ended December 31,
	201 7		201 6		201 5
Cost of Design-to-silicon-yield solutions	$	4,606	$	4,427	$	3,914
Research and development		3,518		3,087		2,275
Selling, general and administrative		3,686		3,488		3,567
Stock-based compensation expense	$	11,810	$	11,002	$	9,756

The stock-based compensation expense for the year

s ended

December 31, 2017,

2016,

and

2015

in the table above includes expense related to cash-settled stock appreciation rights (“SARs”) granted to certain employees which totaled to a credit of

$30,000,

an expense of

$116,000,

and a credit of $

5,000

, respectively. The Company accounted for these awards as a liability and the amount was included in accrued compensation and related benefits.

Stock-based compensation is estimated at the grant date based on the award

’s fair value and is recognized on a straight-line basis over the vesting periods, generally

four

years. As stock-based compensation expense recognized is based on awards ultimately expected to vest, it has been reduced for estimated forfeitures. Forfeitures are estimated at the time of grant and revised, if necessary, in subsequent periods if actual forfeitures differ from those estimates.

The Company has elected to use the Black-Scholes-Merton option-pricing model, which incorporates various assumptions including volatility, expected life and interest rates. The expected volatility is based on the historical volatility of the Company

’s common stock over the most recent period commensurate with the estimated expected life of the Company’s stock options. The expected life of an award is based on historical experience and on the terms and conditions of the stock awards granted to employees. The interest rate assumption is based upon observed Treasury yield curve rates appropriate for the expected life of the Company’s stock options.

The fair value of equity awards granted was estimated on the date of grant with the following weighted average assumptions:

	Stock Plans									Employee Stock Purchase Plan
	201 7			201 6			201 5			201 7			201 6			201 5
Expected life (in years)		4.42			4.4			4.5			1.25			1.25			1.25
Volatility		41.5	%		43.2	%		45.8	%		40.63	%		44.0	%		50.1	%
Risk-free interest rate		1.81	%		1.34	%		1.37	%		1.25	%		0.50	%		0.34	%
Expected dividend		—			—			—			—			—			—

December 31,

201

the Company had in effect the following stock-based compensation plans:

Stock Plans

— At the annual meeting of stockholders on

November 16, 2011,

the Company’s stockholders approved the

2011

Stock Incentive Plan (as amended, the

“2011

Plan”). Under the

2011

Plan, the Company

may

award stock options, stock appreciation rights, stock grants or stock units covering shares of the Company’s common stock to employees, directors, non-employee directors and contractors. The aggregate number of shares reserved for awards under this plan is

9,050,000

shares, plus up to

3,500,000

shares previously issued under the

2001

Plan that are forfeited or repurchased by the Company or shares subject to awards previously issued under the

2001

Plan that expire or that terminate without having been exercised or settled in full on or after

November 16, 2011.

In case of awards other than options or stock appreciation rights, the aggregate number of shares reserved under the plan will be decreased at a rate of

1.33

shares issued pursuant to such awards. The exercise price for stock options must generally be at prices

less than the fair market value at the date of grant. Stock options generally expire

ten

years from the date of grant and become vested and exercisable over a

four

-year period.

2001,

the Company adopted a

2001

Stock Plan (the

“2001

Plan”). In

2003,

in connection with its acquisition of IDS Systems Inc., the Company assumed IDS

’

2001

Stock Option / Stock Issuance Plan (the “IDS Plan”). Both of the

2001

and the IDS Plans expired in

2011.

Stock options granted under the

2001

and IDS Plans generally expire

ten

years from the date of grant and become vested and exercisable over a

four

-year period. Although

new awards

may

be granted under the

2001

or IDS Plans, awards made under the

2001

and IDS Plans that are currently outstanding remain subject to the terms of each such plan.

As of

December 31,

201

9.6

million shares of common stock were reserved to cover stock-based awards under the

2011

Plan, of which

3.9

million shares were available for future grant. The number of shares reserved and available under the

2011

Plan includes

0.5

million shares that were subject to awards previously made under the

2001

Plan and were forfeited, expired or repurchased by the Company after adoption of the

2011

Plan through

December 31, 2017.

As of

December 31, 2017,

there were

outstanding awards that had been granted outside of the

2011,

2001

or the IDS Plans (collectively, the "Stock Plans").

Additional information with respect to options under the Plans is as follows:

	Outstanding Options
	Number of Options (in thousands)			Weighted Average Exercise Price per Share		Weighted Average Remaining Contractual Term (years)		Aggregate Intrinsic Value (in thousands)
Outstanding, January 1, 201 5		2,352			7.65
Granted (weighted average fair value of $ 5.45 per share)		93			13.88
Exercised		(655	)		7.70
Canceled		(23	)		12.95
Expired		(3	)		12.91
Outstanding, December 31, 201 5		1,764			7.88
Granted (weighted average fair value of $5. 36 per share)		99			14.55
Exercised		(393	)		7.56
Canceled		(31	)		13.82
Expired		(75	)		13.80
Outstanding, December 31, 201 6		1,364			8.00
Granted (weighted average fair value of $5. 92 per share)		150			16.28
Exercised		(440	)		6.42
Canceled		(25	)		15.03
Expired		(4	)		16.46
Outstanding, December 31, 201 7		1,045			9.65		4.98	$	6,654
Vested and expected to vest, December 31, 201 7		1,025			9.52		4.89	$	6,641
Exercisable, December 31, 201 7		830			8.06		3.91	$	6,472

The aggregate intrinsic value in the table above represents the total intrinsic value based on the Company

’s closing stock price of

$15.70

as of

December 31, 2017,

which would have been received by the option holders had all option holders exercised their options as of that date. The total intrinsic value of options exercised during the years ended

December 31, 2017,

2016,

and

2015

was

$5.3

million,

$4.4

million, and

$6.2

million, respectively.

As of

December 31,

201

there was

$1.0

million of total unrecognized compensation cost, net of forfeitures, related to unvested stock options. That cost is expected to be recognized over a weighted average period of

3.27

years. The total fair value of options vested during the year ended

December 31, 2017,

was

$0.3

million.

Nonvested shares (restricted stock units) were as follows:

	Shares (in thousands)			Weighted- Average Grant-Date Fair Value
Nonvested, January 1, 201 5		941			17.38
Granted		720			15.92
Vested		(453	)		15.97
Forfeited		(42	)		17.27
Nonvested, December 31, 201 5		1,166			17.03
Granted		963			14.41
Vested		(472	)		17.00
Forfeited		(115	)		15.73
Nonvested, December 31, 201 6		1,542			15.50
Granted		849			16.43
Vested		(646	)		16.26
Forfeited		(128	)		15.71
Nonvested, December 31, 201 7
		1,617			15.66

As of

December 31,

201

there was

$21.0

million of total unrecognized compensation cost related to restricted stock rights. That cost is expected to be recognized over a weighted average period of

2.6

years. Restricted stock units do

not

have rights to dividends prior to vesting.

Employee Stock Purchase Plan

— In

July 2001,

the Company adopted a

ten

-year Employee Stock Purchase Plan (“Purchase Plan”) under which eligible employees can contribute up to

10%

of their compensation, as defined in the Purchase Plan, towards the purchase of shares of PDF common stock at a price of

85%

of the lower of the fair market value at the beginning of the offering period or the end of the purchase period. The Purchase Plan consists of

twenty-four

-month offering periods with

four six

-month purchase periods in each offering period. Under the Purchase Plan, on

January 1

of each year, starting with

2002,

the number of shares reserved for issuance will automatically increase by the lesser of (

)

675,000

shares, (

)

of the Company’s outstanding common stock on the last day of the immediately preceding year, or (

) the number of shares determined by the board of directors. At the annual meeting of stockholders on

May 18, 2010,

the Company's stockholders approved an amendment to the Purchase Plan to extend it through

May 17, 2020.

As of

December 31, 2017,

8.1

million shares of the Company’s common stock have been reserved for issuance under the Purchase Plan. During

2017,

2016,

and

2015,

the number of shares issued were

200,000,

173,000,

and

110,000,

respectively, at a weighted average price of

$9.33,

$9.00,

and

$12.57

per share, respectively. As of

December 31, 2017,

4.3

million shares were available for future issuance under the Purchase Plan. The weighted average estimated fair value of shares granted under the Purchase Plan during

2017,

2016,

and

2015

was

$5.22,

$3.69,

and

$5.51

per share, respectively. As of

December 31, 2017,

there was

$0.3

million of unrecognized compensation cost related to the Purchase Plan. That cost is expected to be recognized over a weighted average period of

1.34

years.

Stock Repurchase Program

—

October 25, 2016,

the Board of Directors adopted a

program, effective immediately, to repurchase up to

$25.0

million of the Company’s common stock both on the open market and in privately negotiated transactions over the next

two

years. During the year ended

December 31, 2017,

the Company repurchased

842,182

shares under this program. As of

December 31, 2017,

842,182

shares had been repurchased at an average price of

$15.93

per share under this program for a total purchase price of

$13.4

million, and

$11.6

million remained available for future repurchases.

Note 7 - Income Taxes

12 Months Ended

Dec. 31, 2017

Notes to Financial Statements

Income Tax Disclosure [Text Block]

. Income Taxes

December 22, 2017,

the

2017

Tax Cuts and Jobs Act (the Act) was enacted into law and significantly changed how the U.S. imposes income tax on multinational corporations. Changes include, but are

not

limited to, a reduction of the corporate income tax rate from

35%

21%,

a transition tax on accumulated foreign earnings and a transition from a worldwide to a territorial tax system. We are required to recognize the effect of the Tax Act in the period of enactment, such as remeasuring our U.S. deferred tax assets and liabilities as well as reassessing the net realizability of our deferred tax assets and liabilities. The provisional amount related to the remeasurement of certain deferred tax assets and liabilities, based on the rates at which they are expected to reverse in the future, was

$3.2

million.

The Act also imposed a

one

-time transition tax, which is based on the Company

’s post-

1986

earnings and profits (E&P) that were previously deferred from U.S. income taxes. The Company estimated there is

impact related to the transition tax. The determination of the transition tax requires further analysis regarding the amount and composition of the Company’s historical foreign earnings, which is expected to be completed in the

second

half of

2018.

The Company doesn’t expect the adjustment to be significant.

The Company has

not

provided for any foreign withholding tax for any undistributed earnings for its foreign subsidiaries as of

December 31, 2017.

The Company intends to permanently reinvest the foreign earnings outside of the U.S.

December 2017,

the SEC staff issued Staff Accounting Bulletin

No.

118,

Income Tax Accounting Implications of the Tax Cuts and Jobs Act (SAB

118

), which allows companies to record provisional amounts during a measurement period

not

to extend more than

one

year beyond the

Act enactment date. Since the

2017

Act was passed late in the

fourth

quarter of

2017,

and ongoing guidance and accounting interpretation are expected over the next

months, we consider the accounting for deferred tax remeasurements, the impact of the transition of U.S. international taxation from a worldwide tax system to a territorial system and other provisions to be incomplete due to the forthcoming guidance and our ongoing analysis. We expect to complete our analysis within the measurement period in accordance with SAB

118.

	Year Ended December 31,
	201 7			201 6		201 5
	(In thousands)
U.S.
Current	$	(141	)	$	410	$	2,022
Deferred		(471	)		208		1,549
Foreign
Current		254			329		341
Withholding		1,654			2,898		3,089
Deferred		(33	)		8		14
Total provision	$	1,263		$	3,853	$	7,015

During the years ended

December 31,

201

2016

and

2015,

income before taxes from U.S. operations was $(

1.2

) million,

$11.3

million and

$17.7

million, respectively, and income before taxes from foreign operations was

$1.1

million,

$1.6

million and

$1.7

million, respectively.

The income tax provision differs from the amount estimated by applying the statutory federal income tax rate (

35%

) for the following reasons (in thousands):

	Year Ended December 31,
	201 7			201 6			201 5
Federal statutory tax provision	$	(26	)	$	4,534		$	6,798
State tax provision		(110	)		283			465
Stock compensation expense		(944	)		45			677
Tax credits		(2,769	)		(4,000	)		(4,166	)
Foreign tax, net		1,641			2,852			3,111
Tax Law Changes		3,247			—			—
Other		224			139			130
Tax provision	$	1,263		$	3,853		$	7,015

As of

December 31,

201

the Company had Federal and California net operating loss carry-forwards (“NOLs”) of approximately

$3.2

million and

$5.6

million. The Federal and California NOLs begin expiring after

2019

and

2028,

respectively.

As of

December 31,

201

the Company had federal and state research and experimental and other tax credit (“R&D credits”) carry-forwards of approximately

$13

million and

$16.5

million, respectively. The federal credits begin to expire after

2027,

while the California credits have

expiration. The extent to which the federal and state credit carry forwards can be used to offset future tax liabilities, respectively,

may

be limited, depending on the extent of ownership changes within any

three

-year period as provided in the Tax Reform Act of

1986

and the California Conformity Act of

1987.

The Company assesses its deferred tax assets for recoverability on a regular basis, and where applicable, a valuation allowance is recorded to reduce the total deferred tax asset to an amount that will, more likely than

not,

be realized in the future. As of

December 31,

201

and

2016,

we believe that most of our deferred tax assets are “more-likely-than

not”

to be realized with the exception of California R&D tax credits that have

not

met the “more-likely-than

not”

realization threshold criteria because on an annual basis and pursuant to current law, we generate more California credits than California tax. As a result, at

December 31, 2017

and

2016,

the excess credits of

$9.0

million and

$6.7

million, respectively continued to be subject to a full valuation allowance. In addition, the Company had approximately

$0.1

million of California NOL carryforward from its acquisition of Syntricity. The Company evaluated positive and negative evidence and concluded that it was more likely than

not

that the California NOL would

not

be fully realizable. As a result of management’s evaluation, the Company recorded full valuation allowance against this deferred tax assets. The Company will continue to review its deferred tax assets in accordance with the applicable accounting standards. Net deferred tax assets balance as of

December 31, 2017

and

2016

was

$15.5

million and

$15.0

million, respectively.

The components of the net deferred tax assets are comprised of (in thousands):

	December 31,
	201 7			201 6
Deferred tax assets

Net operating loss carry forward	$	1,318		$	1,768
Research and development and other credit carry forward		16,626			12,345
Foreign tax credit carry forward		1,754			—
Accruals deductible in different periods		3,285			3,446
Intangible assets		1,325			2,573
Stock-based compensation		1,166			2,285
Valuation allowance		(9,126	)		(6,798	)
Subtotal	$	16,348		$	15,619

Deferred tax liabilities

Fixed assets		(835	)		(619	)
Net Deferred tax assets	$	15,513		$	15,000

In accordance with the provisions of

the accounting standard relating to accounting for uncertain tax positions, the Company classifies its liabilities for income tax exposures as long-term. The Company includes interest and penalties related to unrecognized tax benefits within the Company’s income tax provision. As of

December 31, 2017

and

2016,

the Company had accrued interest and penalties related to unrecognized tax benefits of

$0.7

million and

$0.6

million, respectively. In the years ended

December 31, 2017,

2016,

and

2015,

the Company recognized charges for interest and penalties related to unrecognized tax benefits in the consolidated statements of operations of

$135,000,

$72,000,

and

$28,000,

respectively.

The Company

’s total amount of unrecognized tax benefits, excluding interest and penalties, as of

December 31, 2017

was

$12.9

million, of which

$7.7

million, if recognized, would impact the Company’s effective tax rate. As of

December 31, 2017,

the Company has recorded unrecognized tax benefits of

$3.1

million, including interest and penalties, as long-term income taxes payable in its consolidated balance sheet. The remaining

$9.8

million has been recorded net of our deferred tax assets, of which

$5.2

million is subject to a full valuation allowance. The Company does

not

expect the change in unrecognized tax benefits over the next

twelve

months to materially impact its results of operations and financial position.

The Company conducts business globally and, as a result, files numerous consolidated and separate income tax returns in the U.S.

federal, various state and foreign jurisdictions. Because the Company used some of the tax attributes carried forward from previous years to tax years that are still open, statutes of limitation remain open for all tax years to the extent of the attributes carried forward into tax year

2002

for federal and California tax purposes. The Company is

not

subject to income tax examinations in any other of its major foreign subsidiaries’ jurisdictions.

A reconciliation of the beginning and ending amount of unrecognized tax benefits is as follows (in thousands):

	Amount
Gross unrecognized tax benefits, January 1, 201 5	$	10,428
Increases in tax positions for current year		720
Increase in tax positions for prior years		162
Lapse in statute of limitations		(331	)
Gross unrecognized tax benefits, December 31, 201 5		10,979
Increases in tax positions for current year		1,118
Increases in tax positions for prior years		112
Lapse in statute of limitations		(269	)
Gross unrecognized tax benefits, December 31, 201 6		11,940
Increases in tax positions for current year		1,166
Increases in tax positions for prior years		-
Lapse in statute of limitations		(216	)
Gross unrecognized tax benefits, December 31, 2017	$	12,889

We do

not

provide deferred taxes on undistributed earnings of our foreign subsidiaries as we intend to indefinitely reinvest those earnings

Valuation allowance for deferred tax assets is summarized:

	Balance at Beginning of Period		Charged to Costs and Expenses		Balance assumed in acquisition		Deductions/ Write-offs of Accounts		Balance at End of Period
Valuation allowance for deferred tax assets
201 7	$	6,798	$	2,328	$	0	$	—	$	9,126
201 6		6,205	$	593	$	0	$	—	$	6,798
201 5		5,433	$	557	$	215	$	—	$	6,205

Note 8 - Net Income (Loss) Per Share

12 Months Ended

Dec. 31, 2017

Notes to Financial Statements

Earnings Per Share [Text Block]

. Net Income

(loss)

Per Share

The following is a reconciliation of the numerators and denominators used in computing basic and diluted net income (loss) per share (in thousands except per share amount):

	Year Ended December 31,
	201 7			201 6		201 5
Numerator:
Net income (loss)	$	(1,337	)	$	9,103	$	12,407
Denominator:
Basic weighted-average shares outstanding		32,038			31,373		31,424
Effect of dilutive options and restricted stock		—			1,058		740
Diluted weighted-average shares outstanding		32,038			32,431		32,164

Net income (loss) per share – Basic	$	(0.04	)	$	0.29	$	0.39
Net income (loss) per share – Diluted	$	(0.04	)	$	0.28	$	0.39

For the year ended

December 31, 2017,

there are

potential dilutive common shares included in the computation of diluted net income per share because there was a net loss for the period.

The following table sets forth potential shares of common stock that are

not

included in the diluted net income per share calculation above because to do so would be anti-dilutive for the periods indicated (in thousands):

	December 31,
	201 7		201 6
Outstanding options		—		134
Nonvested shares of restricted stock units		—		18
Employee Stock Purchase Plan		—		121
Total		—		273

Note 9 - Customer and Geographic Information

12 Months Ended

Dec. 31, 2017

Notes to Financial Statements

Segment Reporting Disclosure [Text Block]

. Customer and Geographic Information

Operating segments are defined as components of an enterprise about which separate financial information is available that is evaluated regularly by the chief operating decision maker, or group, in deciding how to allocate resources and in assessing performance.

The Company

’s chief operating decision maker, the chief executive officer, reviews discrete financial information presented on a consolidated basis for purposes of regularly making operating decisions, allocation of resources, and assessing financial performance. Accordingly the Company considers itself to be in

one

operating and reporting segment, specifically the licensing and implementation of yield improvement solutions for integrated circuit manufacturers.

The Company had revenues from individual customers in excess of

10%

of total revenues as follows:

	Year Ended December 31,
Customer	201 7			201 6			201 5
A		40	%		41	%		53	%
B		*			11	%		12	%

represents less than

10%

The Company had accounts receivable balances (including amounts that are unbilled) from individual customers in excess of

10%

of the gross accounts receivable balance as follows:

	December 31,
Customer	201 7			201 6
A		41	%		42	%
C		15	%		13	%

represents less than

10%

Revenues from customers by geographic area based on the location of the customers

’ work sites are as follows (in thousands):

	Year Ended December 31,
	201 7					201 6					201 5
	Revenues		Percentage of Revenues			Revenues		Percentage of Revenues			Revenues		Percentage of Revenues
United States	$	39,631		39	%	$	38,748		36	%	$	45,082		46	%
China		17,872		18			11,436		11			1,125		1
Taiwan		12,494		12			15,216		14			7,862		8
Germany		9,990		10			17,253		16			23,198		24
Rest of the world		21,884		21			24,808		23			20,710		21
Total revenue	$	101,871		100	%	$	107,461		100	%	$	97,977		100	%

Long-lived assets, net by geographic area is as follows (in thousands):

	December 31,
	201 7		201 6
United States	$	24,883	$	18,818
Rest of the world		503		523
Total long-lived assets, net	$	25,386	$	19,341

Note 10 - Financial Instruments

12 Months Ended

Dec. 31, 2017

Notes to Financial Statements

Fair Value Disclosures [Text Block]

. Financial Instruments

Fair value is the exit price, or the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants as of the measurement date. The multiple assumptions used to value financial instruments are referred to as inputs, and a hierarchy for inputs used in measuring fair value is established, that maximizes the use of observable inputs and minimizes the use of unobservable inputs by requiring that the most observable inputs be used when available. Observable inputs reflect assumptions market participants would use in pricing an asset or liability based on market data obtained from independent sources while unobservable inputs reflect a reporting entity

’s pricing based upon its own market assumptions. These inputs are ranked according to a fair value hierarchy that prioritizes the inputs to valuation techniques used to measure fair value into

three

broad levels.

Level

Inputs are quoted prices in active markets for identical assets or liabilities.

Level

Inputs are quoted prices for similar assets or liabilities in an active market, quoted prices for identical or similar assets or liabilities in markets that are

not

active, inputs other than quoted prices that are observable and market-corroborated inputs which are derived principally from or corroborated by observable market data.

Level

Inputs are derived from valuation techniques in which

one

or more significant inputs or value drivers are unobservable.

The following table represents the Company

’s assets measured at fair value on a recurring basis as of

December 31, 2017,

and the basis for that measurement (in thousands):

Assets		Total				Quoted Prices in Active Markets for Identical Assets (Level 1)				Significant Other Observable Inputs (Level 2)				Significant Unobservable Inputs (Level 3)
Money market mutual funds		$	26,638			$	26,638			$	—			$	—

The following table represents the Company

’s assets measured at fair value on a recurring basis as of

December 31, 2016

and the basis for that measurement (in thousands):

Assets		Total				Quoted Prices in Active Markets for Identical Assets (Level 1)				Significant Other Observable Inputs (Level 2)				Significant Unobservable Inputs (Level 3)
Money market mutual funds		$	26,456			$	26,456			$	—			$	—

The Company enters into foreign currency forward contracts to reduce the exposure to foreign currency exchange rate fluctuations on certain foreign currency denominated monetary assets and liabilities, primarily on

third

-party accounts payables and intercompany balances. The primary objective of the Company

’s hedging program is to reduce volatility of earnings related to foreign currency exchange rate fluctuations. The counterparty to these foreign currency forward contracts is a large global financial institution that the Company believes is creditworthy, and therefore, the Company believes the credit risk of counterparty nonperformance is

not

significant. These foreign currency forward contracts are

not

designated for hedge accounting treatment. Therefore, the change in fair value of these contracts is recorded into earnings as a component of other income (expense), net, and offsets the change in fair value of the foreign currency denominated assets and liabilities, which is also recorded in other income (expense), net. For the year ended

December 31, 2017,

2016,

and

2015

the Company recognized a realized gain of

$0.7

million, a realized loss of

$0.4

million, and

$0.8

million, respectively on the contracts, which is recorded in interest and other income (expense), net in the Company’s Consolidated Statements of Operations and Comprehensive Income.

The Company carries these derivatives financial instruments on its Consolidated Balance Sheets at their fair values. The Company

’s foreign currency forward contracts are classified as Level

because it is

not

actively traded and the valuation inputs are based on quoted prices and market observable data of similar instruments. As of

December 31, 2017,

the Company had

one

outstanding forward contract with a notional amount of

$8.2

million and recorded

$12,000

other current assets associated with this outstanding forward contract.

- Definition

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

+ References + Details

Note 11 - Employee Benefit Plan	12 Months Ended
Note 11 - Employee Benefit Plan	Dec. 31, 2017
Notes to Financial Statements
Compensation and Employee Benefit Plans [Text Block]	1 1 . Employee Benefit Plan During 1999, the Company established a 401 (k) tax-deferred savings plan, whereby eligible employees may contribute up to 15% of their eligible compensation with a maximum amount subject to IRS guidelines in any calendar year. Company contributions to this plan are discretionary; no such Company contributions have been made since the inception of this plan.

Note 12 - Selected Quarterly Financial Data (Unaudited)

12 Months Ended

Dec. 31, 2017

Notes to Financial Statements

Quarterly Financial Information [Text Block]

. Selected Quarterly Financial Data (Unaudited)

The following is a summary of the Company

’s quarterly consolidated results of operations (unaudited) for the fiscal years ended

December 31, 2017

and

2016.

	Year Ended December 31, 201 7
	Q1		Q2		Q3		Q4
	(In thousands, except for per share amounts)
Total revenues	$	24,289	$	24,289	$	26,517	$	26,776
Gross profit	$	12,858	$	12,910	$	14,086	$	14,495
Net income	$	517	$	189	$	590	$	(2,634	)
Net income per share:
Basic	$	0.02	$	0.01	$	0.02	$	(0.08	)
Diluted	$	0.02	$	0.01	$	0.02	$	(0.08	)

	Year Ended December 31, 201 6
	Q1		Q2		Q3		Q4
	(In thousands, except for per share amounts)
Total revenues	$	25,081	$	26,688	$	27,259	$	28,433
Gross profit	$	14,875	$	16,034	$	15,807	$	16,297
Net income	$	2,061	$	2,133	$	1,984	$	2,925
Net income per share:
Basic	$	0.07	$	0.07	$	0.06	$	0.09
Diluted	$	0.07	$	0.07	$	0.06	$	0.09

Significant Accounting Policies (Policies)

12 Months Ended

Dec. 31, 2017

Accounting Policies [Abstract]

Basis of Accounting, Policy [Policy Text Block]

Basis of Presentation

— The consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries after the elimination of all significant intercompany balances and transactions.

Use of Estimates, Policy [Policy Text Block]

Use of Estimates

Concentration Risk, Credit Risk, Policy [Policy Text Block]

Concentration of Credit Risk

The Company primarily sells its technologies and services to companies in Asia, Europe and North America within the semiconductor industry.

As of

December

31,

2017,

three

customers accounted for

57%

of the Company’s gross accounts receivable and

one

customer accounted for

40%

of the Company’s revenues for

2017.

As of

December

31,

2016,

two

customers accounted for

55%

of the Company’s gross accounts receivable and

two

customers accounted for

52%

of the Company’s revenues for

2016.

See Note

for further details. The Company does

not

Cash and Cash Equivalents, Policy [Policy Text Block]

Cash, Cash Equivalents

and Short-term Investments

— The Company considers all highly liquid investments with an original maturity of

days or less to be cash equivalents. Investments with original maturities greater than

three

months and less than

one

year are classified as short-term investments.

Property, Plant and Equipment, Policy [Policy Text Block]

Property and Equipment

— Property and equipment are stated at cost and are depreciated using the straight-line method over the estimated useful lives of the related asset as follows:

Computer equipment (years)		3
Software (years)		3
Furniture, fixtures, and equipment (years)	5	-	7
Leasehold improvements	Shorter of estimated useful life or term of lease

Impairment or Disposal of Long-Lived Assets, Policy [Policy Text Block]

Long-lived Assets

— The Company’s long-lived assets, excluding goodwill, consist of property and equipment and intangible assets. The Company periodically reviews its long-lived assets for impairment

For assets to be held and used, the Company initiates its review whenever events or changes in circumstances indicate that the carrying amount of a long-lived asset group

may

not

recoverable, an impairment loss is recorded in the amount by which the carrying amount of the asset group exceeds its fair value.

Goodwill and Intangible Assets, Goodwill, Policy [Policy Text Block]

Goodwill

fourth

not

reduce the fair value of a reporting unit below its carrying amount, including goodwill. If events or circumstances do

not

indicate that the fair value of a reporting unit is below its carrying amount, then goodwill is

not

considered to be impaired and

further testing is required. If further testing is required, the Company performs a

two

-step process. The

first

step involves comparing the fair value of its reporting unit to its carrying value, including goodwill. If the carrying value of the reporting unit exceeds its fair value, the

second

one

reporting unit. There has been

impairment of goodwill for any periods presented.

Revenue Recognition, Policy [Policy Text Block]

Revenue Recognition

— The Company derives revenue from

two

sources: Design-to-silicon-yield solutions and Gainshare performance incentives.

Design-to-silicon-yield solutions

December 31, 2017,

the Company recognized changes in

two

of its project’s profitability from revisions in estimates due to the scope changes that resulted in unfavorable changes of net income of

$1.2

million or

$0.04

per diluted share

. During the year ended

December 31, 2016,

the Company recognized changes in

one

of its project

’s profitability from revisions in estimates due to the scope changes that resulted in favorable changes of net income of

$0.9

million or

$0.03

per diluted share.

Revenue under time and materials contracts for solution implementation services are recognized as the services are performed.

not

exist for the Company’s solution implementation services and software products and because the Company’s services and products include our unique technology, the Company is

not

able to determine

third

not

In some instances, the Company also licenses its D

not

have VSOE for its DFI system, thus the Company uses either TPE or BESP in the allocation of arrangement consideration.

longer have future benefits and are

longer recoverable. Deferred costs balance

was

$0.6

million and

$0.5

million as of

December 31, 2017

and

December 31, 2016,

respectively. The balance was included in prepaid expenses and other current assets and other non-current assets in the accompanying consolidated balance sheets.

The Company also licenses its software products separately from solution implementations. For software license arrangements that do

not

require significant modification or customization of the underlying software, software license revenue is recognized under the residual method when (l) persuasive evidence of an arrangement exists, (

) delivery has occurred, (

) the fee is fixed or determinable, (

) collectability is probable, and (

) the arrangement does

not

) determines whether each element constitutes a separate unit of accounting; (

) determines the fair value of each element using the selling price hierarchy of VSOE, TPE or BESP, as applicable; and (

not

month period is recorded as current deferred revenues and the remaining portion is recorded as non- current deferred revenues. Non-current portion of deferred revenue was

$1.5

million and

$1.5

million respectively as of

December 31, 2017

and

2016.

This balance was recorded in the other non-current liabilities in the accompanying consolidated balance sheets.

Gainshare Performance Incentives

— When the Company enters into a contract to provide yield improvement services, the contract usually includes

two

components: (

) a fixed fee for performance by the Company of services delivered over a specific period of time; and (

) a Gainshare performance incentive component where the customer

may

Receivables, Policy [Policy Text Block]

Accounts Receivable

— Accounts receivable include amounts that are unbilled at the end of the period that are expected to be billed and collected within

-month period. Unbilled accounts receivable are determined on an individual contract basis. Unbilled accounts receivable, included in accounts receivable, totaled

$22.2

million and

$20.8

million as of

December 31, 2017,

and

December 31, 2016,

respectively. Unbilled accounts receivable that are

not

expected to be billed and collected during the succeeding

-month period are recorded in other non-current assets and totaled

$8.6

million and

$9.8

million as of

December 31, 2017

and

2016,

Allowance for doubtful accounts are summarized below:

	Balance at Beginning of Period		Charged to Costs and Expenses		Deductions/ Write-offs of Accounts		Balance at End of Period
Allowance for doubtful accounts
201 7	$	200	$	174	$	—	$	374
201 6	$	299	$	—	$	99	$	200
201 5	$	381	$	—	$	82	$	299

Research, Development, and Computer Software, Policy [Policy Text Block]

Software Development Costs

six

years. The costs to develop software that is marketed externally have

not

Research and Development Expense, Policy [Policy Text Block]

Research and Development

—

Research and development expenses are charged to operations as incurred.

Share-based Compensation, Option and Incentive Plans Policy [Policy Text Block]

Stock-Based Compensation

— Stock-based compensation is estimated at the grant date based on the award’s fair value and is recognized on a straight-line basis over the vesting periods, generally

four

Income Tax, Policy [Policy Text Block]

Income Taxes

not

anticipated. Valuation allowances are provided to reduce deferred tax assets to an amount that in management’s judgment is more likely than

not

to be recoverable against future taxable income.

not

to be sustained. An uncertain income tax position will

not

be recognized if it has less than a

50%

Earnings Per Share, Policy [Policy Text Block]

Net Income Per Share

–

dilutive potential common shares are included in the computation of any diluted per share amount when a loss from continuing operations was reported by the Company.

Foreign Currency Transactions and Translations Policy [Policy Text Block]

Foreign Currency Translation

Derivatives, Policy [Policy Text Block]

Derivative Financial Instruments

not

significant. These foreign currency forward contracts are

not

two

three

months.

Legal Costs, Policy [Policy Text Block]

Litigation

December 31, 2017,

the Company is

not

a party to any material legal proceedings, thus

loss was probable and

amount was accrued.

New Accounting Pronouncements, Policy [Policy Text Block]

Recent Accounting Pronouncements

—

May 2014,

the FASB issued ASU

No.

2014

09,

Revenue from Contracts with Customers (Topic

606

), which supersedes the revenue recognition requirements in “Revenue Recognition (Topic

605

).” Subsequently, the FASB has issued several amendments to the standard, including clarification on accounting for licenses of intellectual property and identifying performance obligations

Under Topic

606,

the new revenue recognition standard provides a

five

December 15, 2017,

including interim periods within that reporting period

In addition, the standard requires

enhanced disclosure of the nature, amount, timing, and uncertainty of revenue and cash flows arising from contracts with customers.

The guidance permits

two

Topic

606

is effective for us beginning with the

first

quarter of fiscal

2018.

We chose to adopt the standard using the modified retrospective transition method

. The use of the modified retrospective transition method requires us to evaluate only contracts that were in effect at the beginning of fiscal

2018

as if

those contracts had been accounted for under Topic

606

not

be retrospectively adjusted.

In preparation for adoption of the standard,

we are implementing changes to policies, processes and controls related to revenue recognition

. We do

not

expect any major change in our financial systems.

While the Company

’s adoption and evaluation of the impact of this new guidance is

not

Generally

, we expect revenue generated under Topic

606

to be recognized earlier than revenue would have been under Topic

605,

both upon adoption and quarterly the foreseeable future. Upon adoption of Topic

606,

this accounting treatment will result in some of our existing deferred revenue and backlog at the beginning of fiscal

2018

being reduced with a corresponding adjustment to retained earnings.

The adoption of Topic

606

will impact our accounting for certain commercial

software multi-element arrangements (“MEA”) that combine software-related deliverables, which

may

include software contracts with varying terms and service elements. Topic

605

requires VSOE to recognize revenue separately for each of the different elements. Topic

606

More judgments and estimates are required under Topic

606

than are required under Topic

605,

including estimating the SSP for each performance obligation identified within our

606

will depend on contract-specific terms and, in some instances,

may

vary from the recognition required under Topic

605.

may

Topic

606

our commission rates paid for renewals are commensurate with the rates paid for initial contracts, we will recognize the deferred direct costs over the contract term.

The modified retrospective transition approach allows us to avoid restating comparative years, however in

2018,

the year of adoption, we are required to provide additoinal disclosure for the amount by which each financial statement line item is affected as a result of applying Topic

606

(as compared to Topic

605

)

February 2016,

the Financial Accounting Standards Board (or FASB) issued ASU

No.

2016

02,

Leases (Topic

842

’ financial statements issued for fiscal years beginning after

December 15, 2018,

August 2016,

the FASB issued ASU

No.

2016

15,

December 15, 2017,

and interim periods within those fiscal years. The adoption of this standard is

not

expected to have a material impact on our financial statements and footnote disclosures.

November 2016,

the FASB issued ASU

No.

2016

18,

December 31, 2018,

though early adoption is permitted. The Company is currently evaluating the impact of adopting this new guidance on its consolidated financial statements.

January 2017,

the FASB issued ASU

No.

2017

01,

December 15, 2017.

The Company does

not

anticipate that the adoption of this standard will have a significant impact on our consolidated financial statements or the related disclosures.

January 2017,

the FASB issued ASU

No.

2017

04,

Intangibles - Goodwill and Other (Topic

350

) (“ASU

No.

2017

04”

). ASU

No.

2017

eliminates step

from the annual goodwill impairment test. This update is effective for annual periods beginning after

December 15, 2019,

and interim periods within those fiscal years, with early adoption permitted, and is to be applied on a prospective basis. The Company does

not

anticipate that the adoption of this standard will have a significant impact on our consolidated financial statements or the related disclosures.

May 2017,

the FASB issued ASU

No.

2017

09,

Compensation-Stock Compensation (Topic

718

) Scope of Modification Accounting (“ASU

No.

2017

09”

). ASU

No.

2017

clarifies which changes to the terms or conditions of a share-based payment award require an entity to apply modification accounting in Topic

718.

The standard is effective for interim and annual reporting periods beginning after

December 15, 2017.

The adoption of this standard will impact modifications that happen after the adoption date.

February 2018,

the FASB issued ASU

No.

2018

02,

Income Statement – Reporting Comprehensive Income Topic

220

December 2017.

This update will be effective for the Company for fiscal years beginning after

December 15, 2018

and interim periods within those fiscal years. Early adoption is permitted.

The Company does

not

anticipate that the adoption of this standard will have a significant impact on our consolidated financial statements or the related disclosures.

Note 1 - Business and Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2017

Notes Tables

Property Plant and Equipment Estimated Useful Lives [Table Text Block]

Computer equipment (years)		3
Software (years)		3
Furniture, fixtures, and equipment (years)	5	-	7
Leasehold improvements	Shorter of estimated useful life or term of lease

Allowance for Doubtful Accounts [Table Text Block]

	Balance at Beginning of Period		Charged to Costs and Expenses		Deductions/ Write-offs of Accounts		Balance at End of Period
Allowance for doubtful accounts
201 7	$	200	$	174	$	—	$	374
201 6	$	299	$	—	$	99	$	200
201 5	$	381	$	—	$	82	$	299

Note 2 - Property and Equipment (Tables)

12 Months Ended

Dec. 31, 2017

Notes Tables

Property, Plant and Equipment [Table Text Block]

	December 31,
	201 7			201 6
Computer equipment	$	10,729		$	10,642
Software		3,348			1,679
Furniture, fixtures, and equipment		3,676			1,185
Leasehold improvements		1,980			1,132
Test equipment		13,796			11,723
Construction-in-progress		12,527			9,550
		46,056			35,911
Accumulated depreciation		(20,670	)		(16,570	)
Total	$	25,386		$	19,341

Note 3 - Business Combination (Tables)

12 Months Ended

Dec. 31, 2017

Notes Tables

Schedule of Recognized Identified Assets Acquired and Liabilities Assumed [Table Text Block]

	(in thousand)			Amortization period (years)


Finite-lived intangible assets :
Developed technology	$	1,720			9
Customer relationship		820			9
Tradename		180			7
Deferred revenue		(190	)
Other receivables		53
Net asset acquired	$	2,583
Goodwill		1,708
Purchase consideration	$	4,291

Note 4 - Goodwill and Intangible Assets (Tables)

12 Months Ended

Dec. 31, 2017

Notes Tables

Schedule of Goodwill [Table Text Block]

	December 31, 201 7
Balance as of December 31, 201 6	$	215
Add: Goodwill from acquisition		1,708
Goodwill adjustment		-
Balance as of December 31, 201 7	$	1,923

Schedule of Finite-Lived Intangible Assets [Table Text Block]

				December 31, 201 7							Decemb er 31, 201 6
	Amortization Period (Years)			Gross Carrying Amount		Accumulated Amortization			Net Carrying Amount		Gross Carrying Amount		Accumulated Amortization			Net Carrying Amount
Acquired identifiable intangibles:

Customer relationships	1	-	9	$	6,740	$	(4,145	)	$	2,595	$	5,920	$	(3,825	)	$	2,095
Developed technology	4	-	6		15,820		(12,829	)		2,991		14,100		(12,359	)		1,741
Tradename	2	-	4		790		(622	)		168		610		(583	)		27
Backlog		1			100		(100	)		-		100		(100	)		-
Patent	7	-	10		1,800		(1,480	)		320		1,800		(1,440	)		360
Other acquired intangibles		4			255		(255	)		-		255		(255	)		-
Total				$	25,505	$	(19,431	)	$	6,074	$	22,785	$	(18,562	)	$	4,223

Schedule of Finite-Lived Intangible Assets, Future Amortization Expense [Table Text Block]

Year Ending December 31,
201 8	$	1,009
201 9		1,009
20 20		1,009
202 1		833
202 2		626
202 3 and thereafter		1,588
Total future amortization expense	$	6,074

Note 5 - Commitments and Contingencies (Tables)

12 Months Ended

Dec. 31, 2017

Notes Tables

Schedule of Future Minimum Rental Payments for Operating Leases [Table Text Block]

Year Ending December 31,
201 8	$	1,767
201 9		535
20 20		445
202 1		361
202 2		101
202 3 and thereafter		26
Total future minimum lease payments	$	3,235

Note 6 - Stockholders' Equity (Tables)

12 Months Ended

Dec. 31, 2017

Notes Tables

Schedule of Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Table Text Block]

	Years Ended December 31,
	201 7		201 6		201 5
Cost of Design-to-silicon-yield solutions	$	4,606	$	4,427	$	3,914
Research and development		3,518		3,087		2,275
Selling, general and administrative		3,686		3,488		3,567
Stock-based compensation expense	$	11,810	$	11,002	$	9,756

Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Table Text Block]

	Stock Plans									Employee Stock Purchase Plan
	201 7			201 6			201 5			201 7			201 6			201 5
Expected life (in years)		4.42			4.4			4.5			1.25			1.25			1.25
Volatility		41.5	%		43.2	%		45.8	%		40.63	%		44.0	%		50.1	%
Risk-free interest rate		1.81	%		1.34	%		1.37	%		1.25	%		0.50	%		0.34	%
Expected dividend		—			—			—			—			—			—

Share-based Compensation, Stock Options, Activity [Table Text Block]

	Outstanding Options
	Number of Options (in thousands)			Weighted Average Exercise Price per Share		Weighted Average Remaining Contractual Term (years)		Aggregate Intrinsic Value (in thousands)
Outstanding, January 1, 201 5		2,352			7.65
Granted (weighted average fair value of $ 5.45 per share)		93			13.88
Exercised		(655	)		7.70
Canceled		(23	)		12.95
Expired		(3	)		12.91
Outstanding, December 31, 201 5		1,764			7.88
Granted (weighted average fair value of $5. 36 per share)		99			14.55
Exercised		(393	)		7.56
Canceled		(31	)		13.82
Expired		(75	)		13.80
Outstanding, December 31, 201 6		1,364			8.00
Granted (weighted average fair value of $5. 92 per share)		150			16.28
Exercised		(440	)		6.42
Canceled		(25	)		15.03
Expired		(4	)		16.46
Outstanding, December 31, 201 7		1,045			9.65		4.98	$	6,654
Vested and expected to vest, December 31, 201 7		1,025			9.52		4.89	$	6,641
Exercisable, December 31, 201 7		830			8.06		3.91	$	6,472

Schedule of Share-based Compensation, Restricted Stock Units Award Activity [Table Text Block]

	Shares (in thousands)			Weighted- Average Grant-Date Fair Value
Nonvested, January 1, 201 5		941			17.38
Granted		720			15.92
Vested		(453	)		15.97
Forfeited		(42	)		17.27
Nonvested, December 31, 201 5		1,166			17.03
Granted		963			14.41
Vested		(472	)		17.00
Forfeited		(115	)		15.73
Nonvested, December 31, 201 6		1,542			15.50
Granted		849			16.43
Vested		(646	)		16.26
Forfeited		(128	)		15.71
Nonvested, December 31, 201 7
		1,617			15.66

Note 7 - Income Taxes (Tables)

12 Months Ended

Dec. 31, 2017

Notes Tables

Schedule of Components of Income Tax Expense (Benefit) [Table Text Block]

	Year Ended December 31,
	201 7			201 6		201 5
	(In thousands)
U.S.
Current	$	(141	)	$	410	$	2,022
Deferred		(471	)		208		1,549
Foreign
Current		254			329		341
Withholding		1,654			2,898		3,089
Deferred		(33	)		8		14
Total provision	$	1,263		$	3,853	$	7,015

Schedule of Effective Income Tax Rate Reconciliation [Table Text Block]

	Year Ended December 31,
	201 7			201 6			201 5
Federal statutory tax provision	$	(26	)	$	4,534		$	6,798
State tax provision		(110	)		283			465
Stock compensation expense		(944	)		45			677
Tax credits		(2,769	)		(4,000	)		(4,166	)
Foreign tax, net		1,641			2,852			3,111
Tax Law Changes		3,247			—			—
Other		224			139			130
Tax provision	$	1,263		$	3,853		$	7,015

Schedule of Deferred Tax Assets and Liabilities [Table Text Block]

	December 31,
	201 7			201 6
Deferred tax assets

Net operating loss carry forward	$	1,318		$	1,768
Research and development and other credit carry forward		16,626			12,345
Foreign tax credit carry forward		1,754			—
Accruals deductible in different periods		3,285			3,446
Intangible assets		1,325			2,573
Stock-based compensation		1,166			2,285
Valuation allowance		(9,126	)		(6,798	)
Subtotal	$	16,348		$	15,619

Deferred tax liabilities

Fixed assets		(835	)		(619	)
Net Deferred tax assets	$	15,513		$	15,000

Schedule of Unrecognized Tax Benefits Roll Forward [Table Text Block]

	Amount
Gross unrecognized tax benefits, January 1, 201 5	$	10,428
Increases in tax positions for current year		720
Increase in tax positions for prior years		162
Lapse in statute of limitations		(331	)
Gross unrecognized tax benefits, December 31, 201 5		10,979
Increases in tax positions for current year		1,118
Increases in tax positions for prior years		112
Lapse in statute of limitations		(269	)
Gross unrecognized tax benefits, December 31, 201 6		11,940
Increases in tax positions for current year		1,166
Increases in tax positions for prior years		-
Lapse in statute of limitations		(216	)
Gross unrecognized tax benefits, December 31, 2017	$	12,889

Valuation Allowance of Deferred Tax Assets [Member]

Notes Tables

Summary of Valuation Allowance [Table Text Block]

	Balance at Beginning of Period		Charged to Costs and Expenses		Balance assumed in acquisition		Deductions/ Write-offs of Accounts		Balance at End of Period
Valuation allowance for deferred tax assets
201 7	$	6,798	$	2,328	$	0	$	—	$	9,126
201 6		6,205	$	593	$	0	$	—	$	6,798
201 5		5,433	$	557	$	215	$	—	$	6,205

Note 8 - Net Income (Loss) Per Share (Tables)

12 Months Ended

Dec. 31, 2017

Notes Tables

Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]

	Year Ended December 31,
	201 7			201 6		201 5
Numerator:
Net income (loss)	$	(1,337	)	$	9,103	$	12,407
Denominator:
Basic weighted-average shares outstanding		32,038			31,373		31,424
Effect of dilutive options and restricted stock		—			1,058		740
Diluted weighted-average shares outstanding		32,038			32,431		32,164

Net income (loss) per share – Basic	$	(0.04	)	$	0.29	$	0.39
Net income (loss) per share – Diluted	$	(0.04	)	$	0.28	$	0.39

Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table Text Block]

	December 31,
	201 7		201 6
Outstanding options		—		134
Nonvested shares of restricted stock units		—		18
Employee Stock Purchase Plan		—		121
Total		—		273

Note 9 - Customer and Geographic Information (Tables)

12 Months Ended

Dec. 31, 2017

Notes Tables

Schedule of Revenue by Major Customers by Reporting Segments [Table Text Block]

	Year Ended December 31,
Customer	201 7			201 6			201 5
A		40	%		41	%		53	%
B		*			11	%		12	%

Receivables by Major Customers [Table Text Block]

	December 31,
Customer	201 7			201 6
A		41	%		42	%
C		15	%		13	%

Schedule of Revenue from External Customers Attributed to Foreign Countries by Geographic Area [Table Text Block]

	Year Ended December 31,
	201 7					201 6					201 5
	Revenues		Percentage of Revenues			Revenues		Percentage of Revenues			Revenues		Percentage of Revenues
United States	$	39,631		39	%	$	38,748		36	%	$	45,082		46	%
China		17,872		18			11,436		11			1,125		1
Taiwan		12,494		12			15,216		14			7,862		8
Germany		9,990		10			17,253		16			23,198		24
Rest of the world		21,884		21			24,808		23			20,710		21
Total revenue	$	101,871		100	%	$	107,461		100	%	$	97,977		100	%

Schedule of Disclosure on Geographic Areas, Long-Lived Assets in Individual Foreign Countries by Country [Table Text Block]

	December 31,
	201 7		201 6
United States	$	24,883	$	18,818
Rest of the world		503		523
Total long-lived assets, net	$	25,386	$	19,341

Note 10 - Financial Instruments (Tables)

12 Months Ended

Dec. 31, 2017

Notes Tables

Fair Value, Assets Measured on Recurring Basis [Table Text Block]

Assets		Total				Quoted Prices in Active Markets for Identical Assets (Level 1)				Significant Other Observable Inputs (Level 2)				Significant Unobservable Inputs (Level 3)
Money market mutual funds		$	26,638			$	26,638			$	—			$	—

Assets		Total				Quoted Prices in Active Markets for Identical Assets (Level 1)				Significant Other Observable Inputs (Level 2)				Significant Unobservable Inputs (Level 3)
Money market mutual funds		$	26,456			$	26,456			$	—			$	—

Note 12 - Selected Quarterly Financial Data (Unaudited) (Tables)

12 Months Ended

Dec. 31, 2017

Notes Tables

Quarterly Financial Information [Table Text Block]

	Year Ended December 31, 201 7
	Q1		Q2		Q3		Q4
	(In thousands, except for per share amounts)
Total revenues	$	24,289	$	24,289	$	26,517	$	26,776
Gross profit	$	12,858	$	12,910	$	14,086	$	14,495
Net income	$	517	$	189	$	590	$	(2,634	)
Net income per share:
Basic	$	0.02	$	0.01	$	0.02	$	(0.08	)
Diluted	$	0.02	$	0.01	$	0.02	$	(0.08	)

	Year Ended December 31, 201 6
	Q1		Q2		Q3		Q4
	(In thousands, except for per share amounts)
Total revenues	$	25,081	$	26,688	$	27,259	$	28,433
Gross profit	$	14,875	$	16,034	$	15,807	$	16,297
Net income	$	2,061	$	2,133	$	1,984	$	2,925
Net income per share:
Basic	$	0.07	$	0.07	$	0.06	$	0.09
Diluted	$	0.07	$	0.07	$	0.06	$	0.09

Note 1 - Business and Significant Accounting Policies (Details Textual) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Number of Reporting Units	1
Goodwill, Impairment Loss	$ 0	$ 0
Impact of Estimates Revisions on Net Income	$ (1,200)	$ 900
Impact of Estimates Revisions on Earnings per Share, Diluted	$ (0.04)	$ 0.03
Deferred Pre-contract Costs	$ 600	$ 500
Unbilled Receivables, Current	22,200	20,800
Unbilled Receivables, Not Billable, Amount Expected to be Collected after Next Twelve Months	$ 8,600	9,800
Capitalized Computer Software, Useful Life	6 years
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period	4 years
Loss Contingency Accrual	$ 0
Other Noncurrent Liabilities [Member]
Deferred Revenue, Noncurrent	$ 1,500	$ 1,500
Customer Concentration Risk [Member] \| Accounts Receivable [Member] \| Three Customers [Member]
Concentration Risk, Percentage	57.00%
Customer Concentration Risk [Member] \| Accounts Receivable [Member] \| Two Customers [Member]
Concentration Risk, Percentage		55.00%
Customer Concentration Risk [Member] \| Sales Revenue, Net [Member] \| One Customer [Member]
Concentration Risk, Percentage	40.00%
Customer Concentration Risk [Member] \| Sales Revenue, Net [Member] \| Two Customers [Member]
Concentration Risk, Percentage		52.00%

Note 1 - Business and Significant Accounting Policies - Estimated Useful Lives of Property and Equipment (Details)	12 Months Ended
	Dec. 31, 2017
Computer Equipment [Member]
Property, plant and equipment, useful life (Year)	3 years
Software and Software Development Costs [Member]
Property, plant and equipment, useful life (Year)	3 years
Furniture and Fixtures [Member] \| Minimum [Member]
Property, plant and equipment, useful life (Year)	5 years
Furniture and Fixtures [Member] \| Maximum [Member]
Property, plant and equipment, useful life (Year)	7 years
Leasehold Improvements [Member]
Property, plant and equipment, useful life	Shorter of estimated useful life or term of lease

Note 1 - Business and Significant Accounting Policies - Allowance for Doubtful Accounts (Details) - Allowance for Doubtful Accounts [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Balance at Beginning of Period	$ 200	$ 299	$ 381
Charged to Costs and Expenses	174
Deductions/ Write-offs of Accounts		99	82
Balance at End of Period	$ 374	$ 200	$ 299

Note 2 - Property and Equipment (Details Textual) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Depreciation, Depletion and Amortization, Nonproduction	$ 4.8	$ 3.6	$ 2.6
DFI Test Equipment [Member]
Construction in Progress, Gross	$ 10.9	$ 8.0

Note 2 - Property and Equipment - Property and Equipment (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Property and equipment, gross	$ 46,056	$ 35,911
Accumulated depreciation	(20,670)	(16,570)
Total	25,386	19,341
Computer Equipment [Member]
Property and equipment, gross	10,729	10,642
Software and Software Development Costs [Member]
Property and equipment, gross	3,348	1,679
Furniture and Fixtures [Member]
Property and equipment, gross	3,676	1,185
Leasehold Improvements [Member]
Property and equipment, gross	1,980	1,132
Test Equipment [Member]
Property and equipment, gross	13,796	11,723
Construction in Progress [Member]
Property and equipment, gross	$ 12,527	$ 9,550

Note 3 - Business Combination (Details Textual) - Kinesys Software [Member] $ in Millions	Jul. 11, 2017 USD ($)
Payments to Acquire Businesses, Gross	$ 4.3
Business Combination Contingent Consideration at Fair Value	0.5
Business Combination, Contingent Consideration Arrangements, Range of Outcomes, Value, High	0.6
Business Acquisition, Goodwill, Expected Tax Deductible Amount	$ 1.7

Note 3 - Business Combination - Assets Acquired and Liabilities Assumed (Details) - USD ($) $ in Thousands	Jul. 11, 2017	Dec. 31, 2017	Dec. 31, 2016
Goodwill		$ 1,923	$ 215
Kinesys Software [Member]
Deferred revenue	$ (190)
Other receivables	53
Net asset acquired	2,583
Goodwill	1,708
Purchase consideration	4,291
Kinesys Software [Member] \| Developed Technology Rights [Member]
Finite-lived intangible assets	$ 1,720
Finite-lived intangible assets, amortization period (Year)	9 years
Kinesys Software [Member] \| Customer Relationships [Member]
Finite-lived intangible assets	$ 820
Finite-lived intangible assets, amortization period (Year)	9 years
Kinesys Software [Member] \| Trade Names [Member]
Finite-lived intangible assets	$ 180
Finite-lived intangible assets, amortization period (Year)	7 years

Note 4 - Goodwill and Intangible Assets (Details Textual) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Goodwill	$ 1,923	$ 215
Finite-Lived Intangible Assets, Net	$ 6,074	4,223
Finite-Lived Intangible Assets, Remaining Amortization Period	6 years 270 days
Amortization of Intangible Assets	$ 869	$ 805	$ 372
Impairment of Intangible Assets, Finite-lived	$ 0

Note 4 - Goodwill and Intangible Assets - Goodwill Activity (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2017 USD ($)
Balance	$ 215
Add: Goodwill from acquisition	1,708
Goodwill adjustment
Balance	$ 1,923

Note 4 - Goodwill and Intangible Assets - Intangible Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Gross Carrying Amount	$ 25,505	$ 22,785
Accumulated Amortization	(19,431)	(18,562)
Intangible assets, net	6,074	4,223
Customer Relationships [Member]
Gross Carrying Amount	6,740	5,920
Accumulated Amortization	(4,145)	(3,825)
Intangible assets, net	$ 2,595	2,095
Customer Relationships [Member] \| Minimum [Member]
Amortization Period (Year)	1 year
Customer Relationships [Member] \| Maximum [Member]
Amortization Period (Year)	9 years
Developed Technology Rights [Member]
Gross Carrying Amount	$ 15,820	14,100
Accumulated Amortization	(12,829)	(12,359)
Intangible assets, net	$ 2,991	1,741
Developed Technology Rights [Member] \| Minimum [Member]
Amortization Period (Year)	4 years
Developed Technology Rights [Member] \| Maximum [Member]
Amortization Period (Year)	6 years
Trade Names [Member]
Gross Carrying Amount	$ 790	610
Accumulated Amortization	(622)	(583)
Intangible assets, net	$ 168	27
Trade Names [Member] \| Minimum [Member]
Amortization Period (Year)	2 years
Trade Names [Member] \| Maximum [Member]
Amortization Period (Year)	4 years
Order or Production Backlog [Member]
Amortization Period (Year)	1 year
Gross Carrying Amount	$ 100	100
Accumulated Amortization	(100)	(100)
Intangible assets, net
Patents [Member]
Gross Carrying Amount	1,800	1,800
Accumulated Amortization	(1,480)	(1,440)
Intangible assets, net	$ 320	360
Patents [Member] \| Minimum [Member]
Amortization Period (Year)	7 years
Patents [Member] \| Maximum [Member]
Amortization Period (Year)	10 years
Other Intangible Assets [Member]
Amortization Period (Year)	4 years
Gross Carrying Amount	$ 255	255
Accumulated Amortization	(255)	(255)
Intangible assets, net

Note 4 - Goodwill and Intangible Assets - Annual Amortization of Identifiable Intangible Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
2018	$ 1,009
2019	1,009
2020	1,009
2021	833
2022	626
2023 and thereafter	1,588
Total future amortization expense	$ 6,074	$ 4,223

Note 5 - Commitments and Contingencies (Details Textual) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Operating Leases, Rent Expense, Net	$ 2,300	$ 2,200	$ 2,100
Purchase Obligation, Due in Next Twelve Months	9,500
Loss Contingency Accrual	$ 0

Note 5 - Commitments and Contingencies - Future Minimum Lease Payments Under Noncancelable Operating Leases (Details) $ in Thousands	Dec. 31, 2017 USD ($)
2018	$ 1,767
2019	535
2020	445
2021	361
2022	101
2023 and thereafter	26
Total future minimum lease payments	$ 3,235

Note 6 - Stockholders' Equity (Details Textual) - USD ($)			12 Months Ended
	May 31, 2017	Oct. 25, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2001
Allocated Share-based Compensation Expense			$ 11,810,000	$ 11,002,000	$ 9,756,000
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period			4 years
Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures in Period			25,000	31,000	23,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number			1,045,000	1,364,000	1,764,000	2,352,000
Share Price			$ 15.70
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Intrinsic Value			$ 5,300,000	$ 4,400,000	$ 6,200,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested in Period, Fair Value			$ 300,000
Stock Repurchase Program, Authorized Amount		$ 25,000,000
Stock Repurchase Program, Period in Force		2 years
Treasury Stock, Shares, Acquired			842,182
Treasury Stock Acquired, Average Cost Per Share			$ 15.93
Treasury Stock, Value, Acquired, Cost Method			$ 13,418,000	$ 2,182,000	$ 14,525,000
Stock Repurchase Program, Remaining Authorized Repurchase Amount			$ 11,600,000
Twenty Eleven Stock Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized	9,050,000
Share Based Compensation Arrangement By Share Based Payment Award Shares Reserved Decrease Rate	1.33
Common Stock, Capital Shares Reserved for Future Issuance			9,600,000
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant			3,900,000
Shares Previously Issued Under the 2001 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized							3,500,000
Two Thousand One Stock Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures in Period			500,000
Outside of the 2011, 2001 or IDS Plans [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number			0
Employee Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period			10 years
Common Stock, Capital Shares Reserved for Future Issuance			8,100,000
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition			1 year 124 days
Share-based Compensation Arrangement by Share-based Payment Award, Maximum Employee Subscription Rate			10.00%
Share-based Compensation Arrangement by Share-based Payment Award, Purchase Price of Common Stock, Percent			85.00%
ESPP Maximum Annual Share Replenishment			675,000
ESPP Maximum Annual Share Replenishment Percentage of Prior Year Outstanding Company Common Stock			2.00%
Stock Issued During Period, Shares, Employee Stock Purchase Plans			200,000	173,000	110,000
Employee Stock Purchase Plan Weighted Average Purchase Price of Shares Purchased			$ 9.33	$ 9	$ 12.57
Number Of ESPP Shares Available For Future Issuance			4,300,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value			$ 5.22	$ 3.69	$ 5.51
Employee Service Share-based Compensation, Nonvested Awards, Compensation Not yet Recognized, Stock Options			$ 300,000
Stock Appreciation Rights (SARs) [Member]
Allocated Share-based Compensation Expense			(30,000)	$ 116,000	$ (5,000)
Employee Stock Option [Member]
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized			$ 1,000,000
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition			3 years 98 days
Employee Stock Option [Member] \| Twenty Eleven Stock Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period	4 years
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period	10 years
Employee Stock Option [Member] \| IDS Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period			4 years
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period			10 years
Restricted Stock Units (RSUs) [Member]
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized			$ 21,000,000
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition			2 years 219 days
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value			$ 16.43	$ 14.41	$ 15.92

Note 6 - Stockholders' Equity - Allocation of Recognized Period Costs (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Allocation of recognized period costs	$ 11,810	$ 11,002	$ 9,756
Cost of Sales [Member]
Allocation of recognized period costs	4,606	4,427	3,914
Research and Development Expense [Member]
Allocation of recognized period costs	3,518	3,087	2,275
Selling, General and Administrative Expenses [Member]
Allocation of recognized period costs	$ 3,686	$ 3,488	$ 3,567

Note 6 - Stockholders' Equity - Stock Options, Valuation Assumptions (Details)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Stock Plans [Member]
Expected life (Year)	4 years 153 days	4 years 146 days	4 years 182 days
Volatility	41.50%	43.20%	45.80%
Risk-free interest rate	1.81%	1.34%	1.37%
Expected dividend	0.00%	0.00%	0.00%
Employee Stock Purchase Plan [Member]
Expected life (Year)	1 year 91 days	1 year 91 days	1 year 91 days
Volatility	40.63%	44.00%	50.10%
Risk-free interest rate	1.25%	0.50%	0.34%
Expected dividend	0.00%	0.00%	0.00%

Note 6 - Stockholders' Equity - Stock Options Activity (Details) - USD ($) $ / shares in Units, shares in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Outstanding (in shares)	1,364	1,764	2,352
Outstanding (in dollars per share)	$ 8	$ 7.88	$ 7.65
Granted (in shares)	150	99	93
Granted (in dollars per share)	$ 16.28	$ 14.55	$ 13.88
Exercised (in shares)	(440)	(393)	(655)
Exercised (in dollars per share)	$ 6.42	$ 7.56	$ 7.70
Canceled (in shares)	(25)	(31)	(23)
Canceled (in dollars per share)	$ 15.03	$ 13.82	$ 12.95
Expired (in shares)	(4)	(75)	(3)
Expired (in dollars per share)	$ 16.46	$ 13.80	$ 12.91
Outstanding (in shares)	1,045	1,364	1,764
Outstanding (in dollars per share)	$ 9.65	$ 8	$ 7.88
Outstanding (Year)	4 years 357 days
Outstanding	$ 6,654
Vested and expected to vest, December 31, 2017 (in shares)	1,025
Vested and expected to vest, December 31, 2017 (in dollars per share)	$ 9.52
Vested and expected to vest, December 31, 2017 (Year)	4 years 324 days
Vested and expected to vest, December 31, 2017	$ 6,641
Exercisable, December 31, 2017 (in shares)	830
Exercisable, December 31, 2017 (in dollars per share)	$ 8.06
Exercisable, December 31, 2017 (Year)	3 years 332 days
Exercisable, December 31, 2017	$ 6,472

Note 6 - Stockholders' Equity - Stock Options Activity (Details) (Parentheticals) - $ / shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Weighted average fair value (in dollars per share)	$ 5.92	$ 5.36	$ 5.45

Note 6 - Stockholders' Equity - Nonvested Restricted Stock Units Activity (Details) - Restricted Stock Units (RSUs) [Member] - $ / shares shares in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Nonvested, Balance (in shares)	1,542	1,166	941
Nonvested, Balance (in dollars per share)	$ 15.50	$ 17.03	$ 17.38
Granted (in shares)	849	963	720
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value	$ 16.43	$ 14.41	$ 15.92
Vested (in shares)	(646)	(472)	(453)
Vested (in dollars per share)	$ 16.26	$ 17	$ 15.97
Forfeited (in shares)	(128)	(115)	(42)
Forfeited (in dollars per share)	$ 15.71	$ 15.73	$ 17.27
Granted (in dollars per share)	16.43	14.41	15.92
Vested (in dollars per share)	16.26	17	15.97
Forfeited (in dollars per share)	$ 15.71	$ 15.73	$ 17.27
Nonvested, Balance (in shares)	1,617	1,542	1,166
Nonvested, Balance (in dollars per share)	$ 15.66	$ 15.50	$ 17.03

Note 7 - Income Taxes (Details Textual) - USD ($)	12 Months Ended
Note 7 - Income Taxes (Details Textual) - USD ($)	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Jul. 17, 2015	Dec. 31, 2014
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent		0.00%
Income Tax Expense (Benefit), Continuing Operations, Adjustment of Deferred Tax (Asset) Liability		$ 3.20
Income (Loss) from Continuing Operations before Income Taxes, Domestic		(1,200,000)	$ 11,300,000	$ 17,700,000
Income (Loss) from Continuing Operations before Income Taxes, Foreign		1,100,000	1,600,000	1,700,000
Deferred Tax Assets, Valuation Allowance		9,126,000	6,798,000
Deferred Tax Assets, Net		15,513,000	15,000,000
Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued		700,000	600,000
Unrecognized Tax Benefits, Income Tax Penalties and Interest Expense		135,000	72,000	28,000
Unrecognized Tax Benefits		12,889,000	11,940,000	$ 10,979,000		$ 10,428,000
Unrecognized Tax Benefits that Would Impact Effective Tax Rate		7,700,000
Unrecognized Tax Benefits In Long Term Liabilities		3,100,000
Unrecognized Tax Benefits In Deferred Tax Assets		9,800,000
Unrecognized Tax Benefits In Deferred Tax Asset Subject To Full Valuation Allowance		5,200,000
Domestic Tax Authority [Member]
Tax Credit Carryforward, Amount		13,000,000
Domestic Tax Authority [Member] \| Internal Revenue Service (IRS) [Member]
Operating Loss Carryforwards		3,200,000
State and Local Jurisdiction [Member]
Tax Credit Carryforward, Amount		16,500,000
State and Local Jurisdiction [Member] \| California Franchise Tax Board [Member]
Operating Loss Carryforwards		5,600,000
Deferred Tax Assets, Valuation Allowance		$ 9,000,000	$ 6,700,000
State and Local Jurisdiction [Member] \| California Franchise Tax Board [Member] \| Syntricity [Member]
Operating Loss Carryforwards					$ 100,000
Scenario, Forecast [Member]
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent	35.00%

Note 7 - Income Taxes - Income Tax Expense (Benefit) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
U.S.
Current	$ (141)	$ 410	$ 2,022
Deferred	(471)	208	1,549
Foreign
Current	254	329	341
Withholding	1,654	2,898	3,089
Deferred	(33)	8	14
Tax provision	$ 1,263	$ 3,853	$ 7,015

Note 7 - Income Taxes - Income Tax Reconciliation (Details) - USD ($)
$ in Thousands

12 Months Ended

Dec. 31, 2017

Dec. 31, 2016

Dec. 31, 2015

Federal statutory tax provision

$ (26)

$ 4,534

$ 6,798

State tax provision

(110)

283

465

Stock compensation expense

^[1]

(944)

677

Tax credits

(2,769)

(4,000)

(4,166)

Foreign tax, net

1,641

2,852

3,111

Tax Law Changes

3,247

Other

224

139

130

Tax provision

$ 1,263

$ 3,853

$ 7,015

[1]

Due to the adoption of ASU 2016-09, excess tax benefits from share-based award activity for the year ended December 31, 2016 are reflected as a reduction of the provision for income taxes, whereas they previously were recognized in equity. See Note 1 "Business and Significant Accounting Policies" in the Notes to the Consolidated Financial Statements for additional information related to this adoption.

Note 7 - Income Taxes - Deferred Tax Assets (Details) - USD ($)	Dec. 31, 2017	Dec. 31, 2016
Deferred tax assets
Net operating loss carry forward	$ 1,318,000	$ 1,768,000
Research and development and other credit carry forward	16,626,000	12,345,000
Foreign tax credit carry forward	1,754,000
Accruals deductible in different periods	3,285,000	3,446,000
Intangible assets	1,325,000	2,573,000
Stock-based compensation	1,166,000	2,285,000
Valuation allowance	(9,126,000)	(6,798,000)
Subtotal	16,348,000	15,619,000
Deferred tax liabilities
Fixed assets	(835,000)	(619,000)
Net Deferred tax assets	$ 15,513,000	$ 15,000,000

Note 7 - Income Taxes - Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Gross unrecognized tax benefits	$ 11,940	$ 10,979	$ 10,428
Increases in tax positions for current year	1,166	1,118	720
Increase in tax positions for prior years		112	162
Lapse in statute of limitations	(216)	(269)	(331)
Gross unrecognized tax benefits	$ 12,889	$ 11,940	$ 10,979

Note 7 - Income Taxes - Valuation Allowance of Deferred Tax Assets (Details) - Valuation Allowance of Deferred Tax Assets [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Balance at Beginning of Period	$ 6,798	$ 6,205	$ 5,433
Charged to Costs and Expenses	2,328	593	557
Balance assumed in acquisition	0	0	215
Deductions/ Write-offs of Accounts
Balance at End of Period	$ 9,126	$ 6,798	$ 6,205

Note 8 - Net Income (Loss) Per Share - Calculation of Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Numerator:
Net income (loss)	$ (2,634)	$ 590	$ 189	$ 517	$ 2,925	$ 1,984	$ 2,133	$ 2,061	$ (1,337)	$ 9,103	$ 12,407
Basic weighted-average shares outstanding (in shares)									32,038	31,373	31,424
Effect of dilutive options and restricted stock (in shares)										1,058	740
Diluted weighted-average shares outstanding (in shares)									32,038	32,431	32,164
Net income (loss) per share – Basic (in dollars per share)	$ (0.08)	$ 0.02	$ 0.01	$ 0.02	$ 0.09	$ 0.06	$ 0.07	$ 0.07	$ (0.04)	$ 0.29	$ 0.39
Net income (loss) per share – Diluted (in dollars per share)	$ (0.08)	$ 0.02	$ 0.01	$ 0.02	$ 0.09	$ 0.06	$ 0.07	$ 0.07	$ (0.04)	$ 0.28	$ 0.39

Note 8 - Net Income (Loss) Per Share - Anti-dilutive Securities (Details) - shares shares in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Anti-dilutive securities (in shares)		273
Employee Stock Option [Member]
Anti-dilutive securities (in shares)		134
Restricted Stock Units RSU Nonvested [Member]
Anti-dilutive securities (in shares)		18
Employee Stock Purchase Plan [Member]
Anti-dilutive securities (in shares)		121

Note 9 - Customer and Geographic Information (Details Textual)	12 Months Ended
	Dec. 31, 2017
Number of Operating Segments	1
Number of Reportable Segments	1

Note 9 - Customer and Geographic Information - Revenue Percentage by Major Customers (Details) - Customer Concentration Risk [Member] - Sales Revenue, Net [Member]

12 Months Ended

Dec. 31, 2017

Dec. 31, 2016

Dec. 31, 2015

Customer A [Member]

Revenue Percentage by Major Customer

40.00%

41.00%

53.00%

Customer B [Member]

Revenue Percentage by Major Customer

^[1]

11.00%

12.00%

[1]	represents less than 10%

Note 9 - Customer and Geographic Information - Receivables Percentage by Major Customers (Details) - Customer Concentration Risk [Member] - Accounts Receivable [Member]	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Customer A [Member]
Revenue Percentage by Major Customer	41.00%	42.00%
Customer B [Member]
Revenue Percentage by Major Customer	15.00%	13.00%

Note 9 - Customer and Geographic Information - Revenues by Geographic Area (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Revenues	$ 26,776	$ 26,517	$ 24,289	$ 24,289	$ 28,433	$ 27,259	$ 26,688	$ 25,081	$ 101,871	$ 107,461	$ 97,977
Geographic Concentration Risk [Member] \| Sales Revenue, Net [Member]
Revenues									$ 101,871	$ 107,461	$ 97,977
Concentration Risk, Percentage									100.00%	100.00%	100.00%
Geographic Concentration Risk [Member] \| Sales Revenue, Net [Member] \| UNITED STATES
Revenues									$ 39,631	$ 38,748	$ 45,082
Concentration Risk, Percentage									39.00%	36.00%	46.00%
Geographic Concentration Risk [Member] \| Sales Revenue, Net [Member] \| CHINA
Revenues									$ 17,872	$ 11,436	$ 1,125
Concentration Risk, Percentage									18.00%	11.00%	1.00%
Geographic Concentration Risk [Member] \| Sales Revenue, Net [Member] \| TAIWAN, PROVINCE OF CHINA
Revenues									$ 12,494	$ 15,216	$ 7,862
Concentration Risk, Percentage									12.00%	14.00%	8.00%
Geographic Concentration Risk [Member] \| Sales Revenue, Net [Member] \| GERMANY
Revenues									$ 9,990	$ 17,253	$ 23,198
Concentration Risk, Percentage									10.00%	16.00%	24.00%
Geographic Concentration Risk [Member] \| Sales Revenue, Net [Member] \| Rest of the World [Member]
Revenues									$ 21,884	$ 24,808	$ 20,710
Concentration Risk, Percentage									21.00%	23.00%	21.00%

Note 9 - Customer and Geographic Information - Long-lived Assets by Geographic Area (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Long-lived assets	$ 25,386	$ 19,341
UNITED STATES
Long-lived assets	24,883	18,818
Rest of the World [Member]
Long-lived assets	$ 503	$ 523

Note 10 - Financial Instruments (Details Textual) - Foreign Exchange Contract [Member] - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Derivative Asset, Notional Amount	$ 8,200,000
Other Current Assets [Member]
Derivative Asset, Current	12,000
Other Nonoperating Income (Expense) [Member]
Derivative, Gain (Loss) on Derivative, Net	$ 700,000	$ (400,000)	$ (800,000)

Note 10 - Financial Instruments - Fair Value, Assets Measured on a Recurring Basis (Details) - Money Market Funds [Member] - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Money market mutual funds	$ 26,638	$ 26,456
Fair Value, Inputs, Level 1 [Member]
Money market mutual funds	26,638	26,456
Fair Value, Inputs, Level 2 [Member]
Money market mutual funds
Fair Value, Inputs, Level 3 [Member]
Money market mutual funds

- Definition

Fair value portion of investment securities, including, but not limited to, marketable securities, derivative financial instruments, and investments accounted for under the equity method.

+ References + Details

Note 11 - Employee Benefit Plan (Details Textual)	12 Months Ended
Note 11 - Employee Benefit Plan (Details Textual)	Dec. 31, 2017
Defined Contribution Plan, Maximum Annual Contributions Per Employee, Percent	15.00%

Note 12 - Selected Quarterly Financial Data (Unaudited) - Selected Quarterly Financial Data (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Revenues	$ 26,776	$ 26,517	$ 24,289	$ 24,289	$ 28,433	$ 27,259	$ 26,688	$ 25,081	$ 101,871	$ 107,461	$ 97,977
Gross profit	14,495	14,086	12,910	12,858	16,297	15,807	16,034	14,875	54,350	63,013	58,954
Net income (loss)	$ (2,634)	$ 590	$ 189	$ 517	$ 2,925	$ 1,984	$ 2,133	$ 2,061	$ (1,337)	$ 9,103	$ 12,407
Basic (in dollars per share)	$ (0.08)	$ 0.02	$ 0.01	$ 0.02	$ 0.09	$ 0.06	$ 0.07	$ 0.07	$ (0.04)	$ 0.29	$ 0.39
Diluted (in dollars per share)	$ (0.08)	$ 0.02	$ 0.01	$ 0.02	$ 0.09	$ 0.06	$ 0.07	$ 0.07	$ (0.04)	$ 0.28	$ 0.39