UNITED STATES SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 10-Q

☑	QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934

	For the Quarterly Period ended June 30 ~~2016~~, 2017

☐	TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934

	For the transition period from _______________ to ______________

Commission File Number 000-31311

PDF SOLUTIONS, INC.

(Exact name of Registrant as Specified in its Charter)

Delaware	25-1701361
(State or Other Jurisdiction of	~~(I.R.S. Employer~~
Incorporation or Organization)	(I.R.S. Employer Identification No.)

333 West San Carlos Street, Suite 1000
San Jose, California	95110
(Address of Principal Executive Offices)	(Zip Code)

(408) 280-7900

(~~Registrant’s~~Registrant’s Telephone Number, Including Area Code)

Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days. Yes ☑ No ☐

Indicate by check mark whether the registrant has submitted electronically and posted on its corporate Web site, if any, every Interactive Data File required to be submitted and posted pursuant to Rule 405 of Regulation S-T (§232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit and post such files). Yes ☑ No ☐

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, or a smaller reporting company. See the definitions of “large accelerated filer,” “accelerated filer” and “smaller reporting company” in Rule 12b-2 of the Exchange Act.

☐ Large accelerated filer	☑ Accelerated filer	~~☐ Non-accelerated filer~~	~~☐ Smaller reporting company~~
		~~(Do~~☐ Non-accelerated filer (Do not check if a smaller reporting company)	☐ Smaller reporting company
☐ Emerging growth company
☐ If an emerging growth company, indicated by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act.

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act). Yes ☐ No ☑

The number of shares outstanding of the ~~Registrant’s~~Registrant’s Common Stock as of July ~~28, 2016~~27, 2017 was ~~31,341,201.~~32,333,162.

TABLE OF CONTENTS

	Page
PART I FINANCIAL INFORMATION
Item 1. Financial Statements (Unaudited)	3
Condensed Consolidated Balance Sheets	3
Condensed Consolidated Statements of Operations and Comprehensive Income	4
Condensed Consolidated Statements of Cash Flows	5
Notes to Condensed Consolidated Financial Statements	6
Item 2. ~~Management’s~~Management’s Discussion and Analysis of Financial Condition and Results of Operations	17 18
Item 3. Quantitative and Qualitative Disclosures About Market Risk	27
Item 4. Controls and Procedures	28
PART II OTHER INFORMATION
Item 1. Legal Proceedings	28
Item 1A. Risk Factors	28
Item 2. Unregistered Sales of Equity Securities and Use of Proceeds	2829
Item 3. Defaults Upon Senior Securities	29
Item 4. Mine Safety Disclosures	29
Item 5. Other Information	29
Item 6. Exhibits	30
SIGNATURES	31
INDEX TO EXHIBITS	32

PART~~PART~~ I — FINANCIAL INFORMATION

Item 1. Financial Statements

PDF SOLUTIONS, INC.

CONDENSED CONSOLIDATED BALANCE SHEETS

(unaudited)

(in thousands, except par value)

	June 30, 2016			December 31, 2015			June 30, 2017			December 31, 2016
ASSETS
Current assets:
Cash and cash equivalents	$	122,222		$	126,158		$	109,007		$	116,787
Accounts receivable, net of allowance of $200 and $299, respectively		34,786			33,438
Accounts receivable, net of allowance of $324 and $200, respectively								54,029			48,157
Prepaid expenses and other current assets		4,728			3,655			8,813			5,335
Total current assets		161,736			163,251			171,849			170,279
Property and equipment, net		16,076			11,325			23,068			19,341
Deferred tax assets		10,106			10,299
Goodwill		215			215			215			215
Intangible assets, net		4,603			5,028			3,847			4,223
Deferred tax assets								15,815			15,640
Other non-current assets		9,497			1,651			12,263			12,631
Total assets	$	202,233		$	191,769		$	227,057		$	222,329
LIABILITIES AND STOCKHOLDERS’ EQUITY
LIABILITIES AND STOCKHOLDERS’ EQUITY
Current liabilities:
Accounts payable	$	2,469		$	1,293		$	2,270		$	2,206
Accrued compensation and related benefits		5,150			4,812			5,863			5,959
Accrued and other current liabilities		2,924			2,382			2,075			2,080
Deferred revenues – current portion		5,740			4,702			8,933			8,189
Billings in excess of recognized revenue		312			1,267			389			88
Total current liabilities		16,595			14,456			19,530			18,522
Long-term income taxes payable		2,594			2,540			3,174			3,354
Other non-current liabilities		328			466			2,253			1,650
Total liabilities		19,517			17,462			24,957			23,526
Commitments and contingencies (Note 9)
Stockholders’ equity:
Stockholders’ equity:
Preferred stock, $0.00015 par value, 5,000 shares authorized, no shares issued and outstanding		—			—			—			—
Common stock, $0.00015 par value, 70,000 shares authorized: shares issued 37,880 and 37,476, respectively; shares outstanding 31,311 and 31,111, respectively		5			5
Common stock, $0.00015 par value, 70,000 shares authorized: shares issued 39,187 and 38,514, respectively; shares outstanding 32,162 and 31,864, respectively								5			5
Additional paid-in-capital		272,886			266,008			289,956			281,423
Treasury stock at cost, 6,569 and 6,365 shares in 2016 and 2015, respectively		(53,301	)		(50,383	)
Treasury stock at cost, 7,025 and 6,650 shares, respectively								(61,532	)		(54,882	)
Accumulated deficit		(35,504	)		(39,780	)		(25,046	)		(25,752	)
Accumulated other comprehensive loss		(1,370	)		(1,543	)		(1,283	)		(1,991	)
Total stockholders’ equity		182,716			174,307
Total liabilities and stockholders’ equity	$	202,233		$	191,769
Total stockholders’ equity								202,100			198,803
Total liabilities and stockholders’ equity							$	227,057		$	222,329

See accompanying Notes to Condensed Consolidated Financial Statements (unaudited).

PDF SOLUTIONS, INC.

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE INCOME

(unaudited)

(in thousands, except per share amounts)

	Three Months Ended June 30,						Six Months Ended June 30,
	2017			2016			2017			2016

Revenues:
Design-to-silicon-yield solutions	$	16,500		$	20,574		$	36,198		$	39,152
Gainshare performance incentives		7,789			6,114			12,380			12,617
Total revenues		24,289			26,688			48,578			51,769

Costs of Design-to-silicon-yield solutions:
Direct costs of Design-to-silicon-yield solutions		11,283			10,558			22,618			20,668
Amortization of acquired technology		96			96			192			192

Total cost of Design-to-silicon-yield solutions		11,379			10,654			22,810			20,860
Gross profit		12,910			16,034			25,768			30,909

Operating expenses:
Research and development		7,276			7,060			14,557			13,371
Selling, general and administrative		6,195			5,094			12,095			10,218
Amortization of other acquired intangible assets		92			117			184			234
Total operating expenses		13,563			12,271			26,836			23,823

Income (loss) from operations		(653	)		3,763			(1,068	)		7,086
Interest and other income (expense), net		27			(51	)		(202	)		(287	)
Income (loss) before income taxes		(626	)		3,712			(1,270	)		6,799
Income tax provision (benefit)		(815	)		1,579			(1,976	)		2,605
Net income	$	189		$	2,133		$	706		$	4,194

Net income per share:
Basic	$	0.01		$	0.07		$	0.02		$	0.13
Diluted	$	0.01		$	0.07		$	0.02		$	0.13

Weighted average common shares:
Basic		32,111			31,276			32,051			31,222
Diluted		33,388			32,099			33,491			31,927


Net income	$	189		$	2,133		$	706		$	4,194
Other comprehensive income:
Foreign currency translation adjustments, net of tax		435			(186	)		708			173
Comprehensive income	$	624		$	1,947		$	1,414		$	4,367

Three Months Ended June 30,

Six Months Ended June 30,

2016

2015

2016

2015

Revenues:

Design-to-silicon-yield solutions
$ 20,574 $ 14,159 $ 39,152 $ 32,311
Gainshare performance incentives
6,114 9,051 12,617 17,716
Total revenues
26,688 23,210 51,769 50,027

Costs of Design-to-silicon-yield solutions:

Direct costs of Design-to-silicon-yield solutions
10,558 9,888 20,668 18,692
Amortization of acquired technology
96 — 192 —
Total cost of Design-to-silicon-yield solutions
10,654 9,888 20,860 18,692
Gross profit
16,034 13,322 30,909 31,335

Operating expenses:

Research and development
7,060 4,437 13,371 8,525
Selling, general and administrative
5,094 5,216 10,218 9,672
Amortization of other acquired intangible assets
117 — 234 —
Total operating expenses
12,271 9,653 23,823 18,197

Income from operations
3,763 3,669 7,086 13,138
Interest and other income (expense), net
(51
)
52 (287
)
103
Income before income taxes
3,712 3,721 6,799 13,241
Income tax provision
1,498 1,572 2,523 5,125
Net income
$ 2,214 $ 2,149 $ 4,276 $ 8,116

Net income per share:

Basic
$ 0.07 $ 0.07 $ 0.14 $ 0.26
Diluted
$ 0.07 $ 0.07 $ 0.13 $ 0.25

Weighted average common shares:

Basic
31,276 31,522 31,222 31,429
Diluted
32,023 32,400 31,872 32,345

Net income
$ 2,214 $ 2,149 $ 4,276 $ 8,116
Other comprehensive income:

Foreign currency translation adjustments, net of tax
(186
)
146 173 (602
)
Comprehensive income
$ 2,028 $ 2,295 $ 4,449 $ 7,514

See accompanying Notes to Condensed Consolidated Financial Statements (unaudited).

PDF SOLUTIONS, INC.

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS

(unaudited)

(in thousands)

	Six Months Ended June 30,						Six Months Ended June 30,
	2016			2015			2017			2016
Operating activities:
Net income	$	4,276		$	8,116		$	706		$	4,194
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization		1,624			1,237			2,286			1,624
Stock-based compensation expense		4,957			4,554			5,788			4,957
Amortization of acquired intangible assets		425			—			376			425
Deferred taxes		192			997			(193	)		1,023
Loss on disposal of property and equipment		107			3			5			107
Purchases of treasury stock in connection with tax withholdings on restricted stock grants		(1,075	)		(1,052	)
Reversal of allowance for doubtful accounts		(99	)		(82	)
Provision for (reversal of) allowance for doubtful accounts								124			(99	)
Unrealized loss (gain) on foreign currency forward contract		(34	)		3			33			(34	)
Tax benefit related to stock-based compensation expense		748			2,094
Excess tax benefit from stock-based compensation		(708	)		(1,980	)
Changes in operating assets and liabilities:
Accounts receivable		(1,249	)		6,861
Prepaid expenses and other assets		(8,908	)		(4,428	)
Accounts receivable, net of allowance								(5,996	)		(1,249	)
Prepaid expenses and other current assets								(3,435	)		(1,057	)
Accounts payable		610			(39	)		851			610
Accrued compensation and related benefits		346			(1,521	)		(223	)		346
Accrued and other liabilities		(223	)		256			(745	)		(223	)
Deferred revenues		947			1,774			726			947
Billings in excess of recognized revenues		(955	)		—			301			(955	)
Other non-current assets								377			(7,852	)
Net cash provided by operating activities		981			16,793			981			2,764
Investing activities:
Purchases of property and equipment		(5,051	)		(2,388	)		(4,964	)		(5,051	)
Net cash used in investing activities		(5,051	)		(2,388	)		(4,964	)		(5,051	)
Financing activities:
Proceeds from exercise of stock options		452			4,764			1,808			452
Proceeds from employee stock purchase plan		778			680			910			778
Excess tax benefit from stock-based compensation		708			1,980
Purchases of treasury stock		(1,843	)		(5,571	)		(4,770	)		(1,843	)
Net cash provided by financing activities		95			1,853
Payments for taxes related to net share settlement of equity awards								(1,879	)		(1,075	)
Net cash (used in) provided by financing activities								(3,931	)		(1,688	)
Effect of exchange rate changes on cash and cash equivalents		39			(23	)		134			39
Net change in cash and cash equivalents		(3,936	)		16,235			(7,780	)		(3,936	)
Cash and cash equivalents, beginning of period		126,158			115,464			116,787			126,158
Cash and cash equivalents, end of period	$	122,222		$	131,699		$	109,007		$	122,222
Supplemental disclosure of cash flow information:
Cash paid during the period for:
Taxes	$	1,336		$	3,920		$	1,339		$	1,336

Property and equipment received and accrued in accounts payable and accrued and other liabilities	$	1,656		$	582		$	1,726		$	1,656

See accompanying Notes to Condensed Consolidated Financial Statements (unaudited).

PDF SOLUTIONS, INC.

NOTES TO CONDENSED CONSOLIDATED FINANCIAL STATEMENTS (UNAUDITED)

1. BASIS OF PRESENTATION

Basis of Presentation

The interim unaudited condensed consolidated financial statements included herein have been prepared by PDF Solutions, Inc. ~~(“the Company”~~(the “Company”) pursuant to the rules and regulations of the Securities and Exchange Commission (“SEC”), including the instructions to the Quarterly Report on Form 10-Q and Article 10 of Regulation S-X. Certain information and footnote disclosures normally included in annual financial statements prepared in accordance with accounting principles generally accepted in the United States of America have been condensed or omitted. The interim unaudited condensed consolidated financial statements reflect, in the opinion of management, all adjustments necessary (consisting only of normal recurring adjustments), to present a fair statement of results for the interim periods presented. The operating results for any interim period are not necessarily indicative of the results that may be expected for other interim periods or the full fiscal year. The accompanying interim unaudited condensed consolidated financial statements should be read in conjunction with the audited consolidated financial statements and notes thereto in the ~~Company’s~~Company’s Annual Report on Form 10-K for the year ended December 31, ~~2015.~~2016.

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

The condensed consolidated balance sheet at December 31, ~~2015,~~2016, has been derived from the audited consolidated financial statements but does not include all disclosures required by accounting principles generally accepted in the United States of America.

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, accounting for goodwill and intangible assets, stock-based compensation expense and accounting for income taxes. Actual results could differ from those estimates.

Revenue Recognition — The Company derives revenue from two sources: Design-to-silicon-yield solutions and Gainshare performance incentives.

~~Design-to-Silicon-Yield Solutions~~ Design-to-silicon-yield solutions — ~~Revenue~~Revenues that isare derived from Design-to-silicon-yield solutions ~~comes~~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–~~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 period ended June 30, 2016, we recognized changes in one project’s profitability from revisions in estimates due to the customer’s directed scope changes that resulted in favorable changes of in our net income for the three months and six months ended June 30, 2016 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.~~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, ~~at each customer's option~~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 ~~fair value.~~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 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 no longer have future benefits and are no longer recoverable. Deferred costs balance was $1.1 million and $0.5 million as of June 30, 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 ~~its~~ 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 ~~(1)~~(l) persuasive evidence of an arrangement exists, (2) delivery has occurred, (3) the fee is fixed or determinable, (4) collectability is probable, and (5) 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 ~~its~~ 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~~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~~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: (1) determines whether each element constitutes a separate unit of accounting; (2) determines the fair value of each element using the selling price hierarchy of VSOE, TPE or BESP, as applicable; and (3) 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~~software-as-a-service (SaaS) that ~~allows~~allow for the use of a hosted software product or service over a contractually determined period of time without taking possession of software isare accounted for as ~~a subscription~~subscriptions and recognized as revenue ratably over the coverage period beginning on the date the service is ~~first~~ 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 ~~primarily~~substantially of amounts invoiced in advance of revenue recognition and ~~are~~is recognized as the revenue recognition criteria are met. Deferred revenues that will be recognized during the succeeding ~~12-month~~12 month period ~~are~~is recorded as current deferred revenues and the remaining portion is recorded as non- current deferred revenues. ~~The non-current~~Non-current portion of deferred revenue was ~~$0.2~~$1.5 million and $1.5 million, respectively, as of June 30, ~~2016~~2017 and ~~$0.3 million as of~~ December 31, ~~2015.~~2016. This balance was recorded in the other non-current liabilities in the accompanying ~~condensed~~ consolidated balance sheets.

Gainshare Performance Incentives — When the Company enters into a contract to provide yield improvement services, the contract usually includes two components: (1) a fixed fee for performance by the Company of services delivered over a specific period of time; and (2) 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 no 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.

2. RECENT ACCOUNTING PRONOUNCEMENTS

~~There have been no developments~~In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606) as modified by ASU No. 2015-14, Revenue from Contracts with Customers (Topic 606): Deferral of the Effective Date, ASU 2016-08, Revenue from Contracts with Customers (Topic 606): Principal versus Agent Considerations (Reporting Revenue Gross versus Net), ASU No. 2016-10, Revenue from Contracts with Customers (Topic 606): Identifying Performance Obligations and Licensing, ASU No. 2016-11, Revenue Recognition (Topic 605) and Derivatives and Hedging (Topic 815), ASU No. 2016-12, Revenue from Contracts with Customers (Topic 606): Narrow-Scope Improvements and Practical Expedients, and ASU 2016-20, Revenue from Contracts with Customers (Topic 606): Technical Corrections and Improvements. The new revenue recognition standard provides a five-step analysis of transactions to ~~recently issued accounting standards,~~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. The new standard also permits two methods of adoption: retrospectively to each prior reporting period presented (full retrospective method), or retrospectively with the ~~expected dates~~cumulative effect of ~~adoption and estimated effects~~initially applying the guidance recognized at the date of initial application (the modified retrospective method). The Company has not yet selected a transition method nor has it determined the effect of the standard on ~~the Company’s consolidated~~its ongoing financial ~~statements and footnote disclosures, from those disclosed in the Company’s 2015 Annual Report on Form 10-K, except for the following:~~reporting

In February 2016, the Financial Accounting Standards Board (or FASB) issued ~~Accounting Standards Update (or ASU)~~ASU No. ~~2016-2,~~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’~~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.

In 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, with early adoption permitted, including adoption in an interim period. The adoption of this standard is not expected to have a material impact on our financial statements and footnote disclosures.

In 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, with early adoption permitted. The Company is currently assessing the impact that adopting this new accounting standard will have on its consolidated financial statements and footnote disclosures.

In ~~March 2016,~~January 2017, the FASB issued ASU No. ~~2016-08, Revenue~~2017-04, Intangibles - Goodwill and Other (Topic 350) (“ASU No. 2017-04”). ASU No. 2017-04 eliminates step 2 from ~~Contracts with Customers (Topic 606): Principal versus Agent Considerations (Reporting Revenue Gross versus Net).~~the annual goodwill impairment test. This update clarifies the implementation guidance on principal versus agent considerations. The guidance includes indicators to assist an entity in determining whether it controls a specified good or service before it is ~~transferred to the customers. The amendments in this update are~~ effective for ~~public companies’ financial statements issued for fiscal years~~annual periods beginning after December 15, ~~2017, including~~2019, and interim periods within those fiscal ~~years.~~years, with early adoption permitted, and is to be applied on a prospective basis. The Company is currently assessing the impact that adopting this new accounting standard will have on its consolidated financial statements and footnote disclosures.

In ~~March 2016,~~May 2017, the FASB issued ASU No. ~~2016-09, Compensation—Stock~~2017-09, Compensation-Stock Compensation (Topic 718)~~: Improvements to Employee Share-Based Payment Accounting. This standard makes several modifications to Topic 718 related~~ Scope of Modification Accounting (“ASU No. 2017-09”). ASU No. 2017-09 clarifies which changes to the ~~accounting for forfeitures, employer tax withholding on~~terms or conditions of a share-based compensation and the financial statement presentation of excess tax benefits or deficiencies. ASU 2016-09 also clarifies the statement of cash flows presentation for certain components of share-based awards. The update is effective for interim and annual reporting periods beginning after December 15, 2016, and interim periods within those annual periods. Early adoption is permitted in any interim or annual period. Ifpayment award require an entity early adopts the amendments in an interim period, any adjustments should be reflected as of the beginning of the fiscal year that includes that interim period. An entity that elects early adoption must adopt all of the amendments in the same period. The Company is currently assessing the impact that adopting this newto apply modification accounting ~~standard will have on its consolidated financial statements and footnote disclosures.~~

In April 2016, the FASB issued ASU No. 2016-10, Revenue from Contracts with Customers (Topic 606): Identifying Performance Obligations and Licensing. The amendments in this update affect entities with transactions included within the scope of Topic 606. The core principle of the guidance in Topic 606 is that an entity should recognize revenue to depict 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.718. The amendments in this Update do not change the core principle of the guidance in Topic 606. Rather, the amendments in this update clarify the following two aspects of Topic 606: identifying performance obligations and the licensing implementation guidance, while retaining the related principles for those areas. The amendments in this update are effective for public companies’ financial statements issued for fiscal years beginning after December 15, 2017, including interim periods within those fiscal years. The Company is currently assessing the impact that adopting this new accounting standard will have on its consolidated financial statements and footnote disclosures.

In May 2016, the FASB issued ASU No. 2016-11, Revenue Recognition (Topic 605) and Derivatives and Hedging (Topic 815): Rescission of SEC Guidance Because of Accounting Standards Updates 2014-09 and 2014-16 pursuant to Staff announcements at the March 3, 2016 EITF Meeting. The purpose of this standard is to rescind from the FASB Accounting Standards Codification certain SEC paragraphs as a result of two SEC Staff Announcements at the March 3, 2016 meeting. The amendments in this update related to Topic 605 are effective for interim and annual reporting periods beginning after December 15, 2017 and amendments related to Topic 815 are effective for interim and annual reporting periods beginning after December 15, 2015. The Company is currently assessing the impact that adopting this new accounting standard will have on its consolidated financial statements and footnote disclosures.

In May 2016, the FASB issued ASU No. 2016-12, Revenue from Contracts with Customers (Topic 660): Narrow-Scope Improvements and Practical Expedients. The purpose of this standard is to clarify certain narrow aspects of Topic 660 such as assessing the collectability criterion, presentation of sales taxes and other similar taxes collected from customers, noncash consideration, contract modifications at transition, completed contracts at transition, and technical correction. This standard is effective for interim and annual reporting periods beginning after December 15, ~~2017.~~2017, with early adoption permitted. The ~~Company is currently assessing the impact that adopting~~adoption of this ~~new accounting~~ standard will ~~have on its consolidated financial statements and footnote disclosures.~~impact modifications that happen after the adoption date.

3. BALANCE SHEET COMPONENTS

Accounts receivable include amounts that are unbilled at the end of the period that are expected to be billed and collected within 12-month period. Unbilled accounts receivable are primarily determined on an individual contract basis. Unbilled accounts receivable, included in accounts receivable, totaled ~~$15.4~~$21.0 million and ~~$11.5~~$20.8 million as of June 30, ~~2016~~2017 and December 31, ~~2015,~~2016, respectively. Unbilled accounts receivable that are not expected to be billed and collected during the succeeding 12-month period are recorded in other non-current assets and totaled ~~$8.0~~$9.7 million and ~~$0.1~~$9.8 million as of June 30, ~~2016~~2017 and December 31, ~~2015,~~2016, respectively. ~~The increase in other non-current asset is due to the increase in the long-term unbilled portion of two of the Company’s Design-to-silicon-yield solutions contracts.~~ Deferred ~~cost~~costs balance was ~~$0.7~~$1.1 million and ~~zero~~$0.5 million as of June 30, 2017 and December 31, 2016, respectively. The balance was included in prepaid expense and ~~2015, respectively.~~other current assets and other non-current assets in the accompanying balance sheets.

Property and equipment, netconsists of (in thousands):

	June 30, 2016			December 31, 2015			June 30, 2017			December 31, 2016
Property and equipment, net:
Computer equipment	$	10,209		$	9,188		$	10,735		$	10,642
Software		1,828			1,713			3,341			1,679
Furniture, fixtures and equipment		963			907			1,821			1,185
Leasehold improvements		1,123			1,126			1,972			1,132
Test equipment		9,667			7,214			12,597			11,723
Construction-in-progress		7,432			4,777			11,128			9,550
		31,222			24,925			41,594			35,911
Less: accumulated depreciation		(15,146	)		(13,600	)		(18,526	)		(16,570	)
Total	$	16,076		$	11,325		$	23,068		$	19,341

Depreciation and amortization expense was ~~$0.9~~$1.2 million and ~~$0.6~~$0.9 million for the three months ended June 30, ~~2016~~2017 and ~~2015,~~2016, respectively. Depreciation and amortization expense was ~~$1.6~~$2.3 million and ~~$1.2~~$1.6 million for the six months ended June 30, 2017 and 2016, ~~and 2015,~~ respectively.

As of both June 30, ~~2016~~2017 and December 31, ~~2015,~~2016, the carrying amount of goodwill was $0.2 million. The following is a rollforward of the Company's goodwill balance (in thousands):

June 30,
2016

Balance as of December 31, 2015
$ 215
Adjustment
—
Balance as of June 30, 2016
$ 215

	June 30, 2017
Balance as of December 31, 2016	$	215
Add: Goodwill from acquisition		—
Adjustment		—
Balance as of June 30, 2017	$	215

Intangible assets balance was ~~$4.6~~$3.8 million and ~~$5.0~~$4.2 million as of June 30, ~~2016~~2017 and December 31, ~~2015,~~2016, respectively. Intangible assets as of June 30, ~~2016~~2017 and December 31, ~~2015~~2016 consist of the following (in thousands):

				June 30, 2016							December 31, 2015										June 30, 2017							December 31, 2016
	Amortization Period (Years)			Gross Carrying Amount		Accumulated Amortization			Net Carrying Amount		Gross Carrying Amount		Accumulated Amortization			Net Carrying Amount		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	$	5,920	$	(3,686	)	$	2,234	$	5,920	$	(3,547	)	$	2,373	1	-	9	$	5,920	$	(3, 964	)	$	1,956	$	5,920	$	(3,825	)	$	2,095
Developed technology	4	-	6		14,100		(12,167	)		1,933		14,100		(11,976	)		2,124	4	-	6		14,100		(12,551	)		1,549		14,100		(12,359	)		1,741
Tradename	2	-	4		610		(558	)		52		610		(533	)		77	2	-	4		610		(608	)		2		610		(583	)		27
Backlog		1			100		(96	)		4		100		(46	)		54		1			100		(100	)		-		100		(100	)		-
Patent	7	-	10		1,800		(1,420	)		380		1,800		(1,400	)		400	7	-	10		1,800		(1,460	)		340		1,800		(1,440	)		360
Other acquired intangibles		4			255		(255	)		-		255		(255	)		-		4			255		(255	)		-		255		(255	)		-
Total				$	22,785	$	(18,182	)	$	4,603	$	22,785	$	(17,757	)	$	5,028				$	22,785	$	(18,938	)	$	3,847	$	22,785	$	(18,562	)	$	4,223

The weighted average amortization period for acquired identifiable intangible assets was ~~6.83~~5.97 years as of June 30, ~~2016.~~2017. For both the three months ended June 30, ~~2016~~2017 and ~~2015,~~2016, intangible asset amortization expense was $0.2 ~~million and zero, respectively.~~million. For both the six months ended June 30, ~~2016~~2017 and ~~2015,~~2016, intangible asset amortization expense was $0.4 ~~million and zero, respectively.~~million. The Company expects annual amortization of acquired identifiable intangible assets to be as follows (in thousands):

Period Ending June 30,
2016 (remaining 6 months)	$	380
2017		728
Period Ending June 30,
2017 (remaining 6 months)			$	353
2018		701		701
2019		701		701
2020		701		701
2021 and thereafter		1,392
2021				526
2022 and thereafter				865
Total future amortization expense	$	4,603	$	3,847

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 the three and six months ended June 30, ~~2016,~~2017, there were no indicators of impairment related to the Company’s intangible assets.

~~4. STOCKHOLDERS’ EQUITY~~

4. STOCKHOLDERS’ EQUITY

Stock-based compensation is estimated at the grant date based on the ~~award’s~~award’s fair value and is recognized on a straight-line basis over the vesting periods, generally four years. Stock-based compensation expense before taxes related to the Company’s stock plans and employee stock purchase plan was allocated as follows (in thousands):

	Three Months Ended June 30,				Six Months Ended June 30,				Three Months Ended June 30,				Six Months Ended June 30,
	2016		2015		2016		2015		2017		2016		2017		2016
Cost of design-to-silicon yield-solutions	$	956	$	914	$	2,041	$	1,801	$	1,069	$	956	$	2,261	$	2,041
Research and development		651		510		1,357		1,001		848		651		1,682		1,357
Selling, general and administrative		684		931		1,559		1,752		987		684		1,845		1,559
Stock-based compensation expense	$	2,291	$	2,355	$	4,957	$	4,554
Stock-based compensation expenses									$	2,904	$	2,291	$	5,788	$	4,957

On June 30, ~~2016,~~2017, the Company had the following stock-based compensation plans:

Stock Plans —All new equity awards are issued by the Company under its 2011 Stock Incentive Plan, as amended and restated from time to time (the “2011 Plan”). The 2011 Plan was initially approved by the Company’s stockholders atAt the annual meeting of stockholders on November 16, 2011, ~~and then again – as~~the Company’s stockholders approved the 2011 Stock Incentive Plan, which was amended and restated ~~each time –at~~(i) at the ~~2013~~ annual meeting of stockholders on May 28, 2013, when the ~~2014~~Company’s stockholders approved the First Amended and Restated 2011 Stock Incentive Plan, (ii) at the annual meeting of stockholders on May 27, 2014, when the Company’s stockholders approved the Second Amended and ~~most recently~~Restated 2011 Stock Incentive Plan, (iii) at the annual meeting of stockholders on May 31, ~~2016.~~2016, when the Company’s stockholders approved the Third Amended and Restated 2011 Stock Incentive Plan, (iv) at the annual meeting of stockholders on May 31, 2017,when the Company’s stockholders approved the Fourth Amended and Restated 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~~Company’s common stock to employees, directors, non-employee directors and contractors. The aggregate number of shares reserved for awards under this plan is ~~7,800,000~~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 no 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.

In 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 2001Plan and the IDS ~~Plan~~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 no 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 applicable.~~respectively.

The Company estimated the fair value of share-based awards granted under the 2011 Stock Plan during the period using the Black-Scholes-Merton option-pricing model with the following weighted average assumptions, resulting in the following weighted average fair values:

	Three Months Ended June 30,						Six Months Ended June 30,						Three Months Ended June 30,						Six Months Ended June 30,
	2016			2015			2016			2015			2017			2016			2017			2016
Expected life (in years)		4.42			4.51			4.42			4.51			4.41			4.42			4.41			4.42
Volatility		43.58	%		46.8	%		44.26	%		46.7	%		41.63	%		43.58	%		41.53	%		44.26	%
Risk-free interest rate		1.30	%		1.41	%		1.25	%		1.34	%		1.67	%		1.30	%		1.69	%		1.25	%
Expected dividend		—			—			—			—			—			—			—			—
Weighted average fair value per share of options granted during the period	$	5.00		$	6.61		$	4.46		$	6.50		$	5.98		$	5.00		$	6.16		$	4.46

As of June 30, ~~2016, 8.3~~2017, 9.6 million shares of common stock were reserved to cover stock-based awards under the 2011 Plan, of which ~~4.5~~2.5 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 June 30, ~~2016.~~2017. As of June 30, ~~2016,~~2017, there were no outstanding awards that had been granted outside of the 2011 Plan, 2001 Plan or the IDS ~~Plans~~Plan (collectively, the ~~"Stock Plans"~~“ Stock Plans” ).

Stock option activity under the ~~Company’s~~Company’s Stock Plans during the six months ended June 30, ~~2016,~~2017, was as follows:

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, 2016
1,764 $ 7.88
Granted (weighted average fair value of $4.46 per share)
50 $ 11.87
Exercised
(63
)
$ 7.20
Canceled
(7
)
$ 15.01
Expired
(75
)
$ 13.79
Outstanding, June 30, 2016
1,669 $ 7.73 4.87 $ 10,719
Vested and expected to vest, June 30, 2016
1,660 $ 7.70 4.84 $ 10,704
Exercisable, June 30, 2016
1,523 $ 7.17 4.49 $ 10,539

	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, 2017		1,364		$	8.00
Granted (weighted average fair value of $6.16 per share)		96		$	17
Exercised		(257	)	$	7.04
Canceled		(3	)	$	17.80
Expired		-		$	-
Outstanding, June 30, 2017		1,200		$	8.89		4.78	$	9,288
Vested and expected to vest, June 30, 2017		1,182		$	8.78		4.71	$	9,271
Exercisable, June 30, 2017		989		$	7.42		3.86	$	9,010

The aggregate intrinsic value in the table above represents the total intrinsic value based on the ~~Company’s~~Company’s closing stock price of ~~$13.99~~$16.45 per share as of June 30, ~~2016.~~2017. The total intrinsic value of options exercised during the six months ended June 30, ~~2016,~~2017, was ~~$0.4~~$3.1 million.

As of June 30, ~~2016,~~2017, there was ~~$0.6~~$1.0 million of total unrecognized compensation cost related to unvested stock options. That cost is expected to be recognized over a weighted average period of ~~3.0~~3.4 years. The total fair value of shares vested during the six months ended June 30, ~~2016,~~2017, was ~~$0.5~~$0.2 million.

Nonvested restricted stock units activity during the six months ended June 30, ~~2016,~~2017, was as follows:

	Shares (in thousands)			Weighted Average Grant Date Fair Value Per Share		Shares (in thousands)			Weighted Average Grant Date Fair Value Per Share
Nonvested, January 1, 2016		1,166		$	17.03
Nonvested, January 1, 2017							1,542		$	15.50
Granted		50		$	11.87		751		$	16.56
Vested		(258	)	$	16.70		(317	)	$	16.36
Forfeited		(42	)	$	17.27		(20	)	$	15.70
Nonvested, June 30, 2016		916		$	16.83
Nonvested, June 30, 2017							1,956		$	15.76

As of June 30, ~~2016,~~2017, there was ~~$13.6~~$26.1 million of total unrecognized compensation cost related to nonvested restricted stock units. That cost is expected to be recognized over a weighted average period of ~~2.4~~3 years. Restricted stock units do not have rights to dividends prior to vesting.

In June 2016, the Company’s Compensation Committee approved 16,375 shares of stock options and 841,533 restricted stock units to be granted effective July 1, 2016. The weighted average exercise price for the options granted is $14.14 per share. The weighted average grant date fair value per share for the restricted stock units granted is $14.14. The cost is expected to be recognized over the vesting period, generally 4 years.

Employee Stock Purchase Plan— In July 2001, the Company adopted a ten-year Employee Stock Purchase Plan (as amended, the “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 (1) 675,000 shares, (2) 2% of the Company’s outstanding common stock on the last day of the immediately preceding year, or (3) 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.

The Company estimated the fair value of purchase rights granted under the Purchase Plan during the period using the Black-Scholes-Merton option-pricing model with the following weighted average assumptions, resulting in the following weighted average fair values:

Six months
EndedJune 30,

2016

2015

Expected life (in years)
1.25 1.25
Volatility
44.15
%
54.21
%
Risk-free interest rate
0.50
%
0.26
%
Expected dividend
— —
Weighted average fair value of purchase rights granted under the Purchase Plan
$ 3.56 $ 6.19

	Six Months Ended June 30,
	2017			2016
Expected life (in years)		1.25			1.25
Volatility		33.32	%		44.15	%
Risk-free interest rate		0.93	%		0.50	%
Expected dividend		—			—
Weighted average fair value per share of options granted during the period	$	6.78		$	3.56

During the three months ended June 30, ~~2016~~2017 and ~~2015,~~2016, the Company did not issue any shares under the Purchase Plan. During the six months ended June 30, ~~2016~~2017 and ~~2015,~~2016, a total of ~~84,000~~100,000 and ~~51,000~~84,000 shares, respectively, were issued at a weighted-average purchase price of ~~$9.21~~$9.13 and ~~$13.32~~$9.21 per share, ~~respectively, under the Purchase Plan.~~respectively. As of June 30, ~~2016,~~2017, there was ~~$1.1~~$0.6 million of unrecognized compensation cost related to the Purchase Plan. That cost is expected to be recognized over a weighted average period of ~~1.6~~0.89 years. As of June 30, ~~2016, 2.7~~2017, 4.4 million shares were available for future issuance under the Purchase Plan.

Stock Repurchase Program—On October ~~21, 2014,~~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 three and six months ended June 30, ~~2016,~~2017, the Company repurchased ~~129,457~~276,279 shares under this program. As of June 30, ~~2016, 1,219,230~~2017, 276,279 shares had been repurchased at an average price of ~~$13.43~~$17.27 per share under this program for a total purchase of ~~$16.4~~$4.8 million, and ~~$8.6~~$20.2 million remained available for future repurchases.

5. INCOME TAXES

Income tax provision decreased $4.6 million for the six months ended June 30, 2017, to $2.0 million income tax benefit as compared to an income tax provision of $2.6 million for the six months ended June 30, ~~2016, to $2.5 million as compared to an income~~2016. The Company’s effective tax ~~provision of $5.1 million~~rate was 155.6% and 38.3% for the six months ended June 30, ~~2015. The Company’s effective tax rate was 37.1%~~2017 and ~~38.7% for the six months ended June 30,~~ 2016, ~~and June 30, 2015,~~ respectively. The Company’s effective tax rate ~~decreased~~increased in the six months ended June 30, ~~2016,~~2017, as compared to the same period in ~~2015,~~2016, primarily due to the ~~permanent reinstatement~~recognition of excess tax benefits related to employee stock compensation of $1.1 million as well as the U.S. federal research tax credit. On December 18, 2015, the President of the United States signed into law the Protecting Americans from Tax Hikes Act of 2015 which permanently reinstated the research tax credit retroactive to January 1, 2015. As a result of the new legislation, the Company recognized a benefitdecrease in ~~the first two quarters of 2016 and no benefit in the same period in 2015.~~income.

The ~~Company’s~~Company’s total amount of unrecognized tax benefits, excluding interest and penalties, as of June 30, ~~2016,~~2017, was ~~$11.3~~$11.5 million, of which ~~$6.7~~$6.9 million, if recognized, would decrease the Company’s effective tax rate. The Company’s total amount of unrecognized tax benefits, excluding interest and penalties, as of December 31, ~~2015,~~2016, was ~~$11.0~~$11.9 million, of which ~~$6.5~~$7.2 million, if recognized, would affect the Company's effective tax rate. As of June 30, ~~2016,~~2017, the Company ~~has~~had recorded unrecognized tax benefits of $2.6 million, including interest and penalties, as long-term taxes payable in its condensed consolidated balance sheet. The remaining ~~$9.2~~$9.3 million has been recorded net of our deferred tax assets, of which $4.6 million is subject to a full valuation allowance.

The valuation allowance was approximately ~~$6.4~~$6.5 million and ~~$6.2~~$6.8 million as of June 30, ~~2016~~2017 and December 31, ~~2015,~~2016, respectively, which was related to California R&D tax credits and California net operating losses related to our acquisition of Syntricity that we currently do not believe are more likely than not to be ultimately realized.

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 ~~State of New York is currently conducting an audit of the Company’s 2012 to 2014 income tax returns. The~~ Company is not subject to income tax examinations in any ~~other~~ of its major foreign subsidiaries’ jurisdictions.

6. 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. Under the treasury stock method, the amount that the employee must pay for exercising stock options, the amount of compensation cost for future service that the Company has not yet recognized, and the amount of the tax benefits that would be recorded in additional paid-in capital when the award becomes deductible are assumed to be used to repurchase shares. The following is a reconciliation of the numerators and denominators used in computing basic and diluted net income per share (in thousands except per share amount):

	Three Months Ended June 30,				Six Months Ended June 30,				Three Months Ended June 30,				Six Months Ended June 30,
	2016		2015		2016		2015		2017		2016		2017		2016
Numerator:
Net income	$	2,214	$	2,149	$	4,276	$	8,116	$	189	$	2,133	$	706	$	4,194
Denominator:
Basic weighted average common shares outstanding		31,276		31,522		31,222		31,429		32,111		31,276		32,051		31,222
Dilutive effect of equity incentive plans		747		878		650		916		1,277		823		1,440		705
Diluted weighted average common shares outstanding		32,023		32,400		31,872		32,345		33,388		32,099		33,491		31,927
Net income per share:
Basic	$	0.07	$	0.07	$	0.14	$	0.26	$	0.01	$	0.07	$	0.02	$	0.13
Diluted	$	0.07	$	0.07	$	0.13	$	0.25	$	0.01	$	0.07	$	0.02	$	0.13

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):

	Three Months Ended June 30,				Six Months Ended June 30,				Three Months Ended June 30,				Six Months Ended June 30,
	2016		2015		2016		2015		2017		2016		2017		2016
Outstanding options		230		58		264		52		102		230		79		264
Nonvested restricted stock units		348		62		798		64		13		348		4		798
Employee Stock Purchase Plan		—		215		230		239		27		—		29		230
Total		578		335		1,292		355		142		578		112		1,292

7. 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~~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 ~~companies designing and/or manufacturing~~ integrated ~~circuits.~~ circuits manufacturers.

The Company had revenues from individual customers in excess of 10% of total revenues as follows:

	Three Months Ended June 30,						Six Months Ended June 30,
Customer	2017			2016			2017			2016
A		36	%		39	%		42	%		44	%
B		15	%		*	%		10	%		*	%
C		*	%		*	%		*	%		12	%
D		*	%		13	%		*	%		*	%

Three Months
Ended June 30,

Six Months
Ended June 30,

Customer

2016

2015

2016

2015

A
39
%
54
%
44
%
49
%
B
*
%
16
%
*
%
13
%
C
*
%
*
%
12
%
17
%
D
13
%
*
%
*
%
*
%

*	represents less than 10%

The Company had gross accounts receivable from individual customers in excess of 10% of gross accounts receivable as follows:

Customer	June 30, 2016			December 31, 2015			June 30, 2017			December 31, 2016
A		50	%		65	%		41	%		42	%
D		12	%		*	%
B								19	%		13	%

*	represents less than 10%

Revenues from customers by geographic area based on the location of the ~~customers’~~customers’ work sites are as follows (in thousands):

	Three Months EndedJune 30,										Three Months Ended June 30,
	2016					2015					2017					2016
	Revenues		Percentage of Revenues			Revenues		Percentage of Revenues			Revenues		Percentage of Revenues			Revenues		Percentage of Revenues
United States	$	9,518		36	%	$	11,436		49	%	$	9,226		38	%	$	9,518		36	%
China												4,753		20			1,499		6
Taiwan		5,725		21			2,160		9			3,643		15			5,725		21
Germany		3,994		15			6,345		27			1,794		7			3,994		15
South Korea		2,184		8			627		3
Rest of the world		5,267		20			2,642		12			4,873		20			5,952		22
Total revenue	$	26,688		100	%	$	23,210		100	%	$	24,289		100	%	$	26,688		100	%

	Six Months Ended June 30,
	2017					2016
	Revenues		Percentage of Revenues			Revenues		Percentage of Revenues
United States	$	20,860		43	%	$	21,640		42	%
Taiwan		7,480		15			7,909		15
China		6,440		13			2,598		5
Germany		4,102		8			7,028		14
South Korea		3,620		7			5,497		11
Rest of the world		6,076		14			7,097		13
Total revenue	$	48,578		100	%	$	51,769		100	%

Six Months Ended June 30,

2016

2015

Revenues

Percentage
of
Revenues

Revenues

Percentage
of
Revenues

United States
$ 21,640 42
%
$ 21,750 43
%
Taiwan
7,909 15 3,279 7
Germany
7,028 14 12,609 25
South Korea
5,497 11 7,545 15
Rest of the world
9,695 18 4,844 10
Total revenue
$ 51,769 100
%
$ 50,027 100
%

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

	June 30, 2016		December 31, 2015		June 30, 2017		December 31, 2016
United States	$	15,559	$	10,752	$	22,501	$	18,818
Rest of the world		517		573		568		523
Total long-lived assets, net	$	16,076	$	11,325	$	23,068	$	19,341

8. FAIR VALUE MEASUREMENTS

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~~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 1 -

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


Level 2 -	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 3 -	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~~Company’s assets measured at fair value on a recurring basis as of June 30, ~~2016,~~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
$ 26,415 $ 26,415 $ — $ —

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

26,522

—

The following table represents the ~~Company’s~~Company’s assets measured at fair value on a recurring basis as of December 31, ~~2015,~~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

—

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~~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 three months ended June 30, ~~2016~~2017 and 2015, the Company recognized a realized loss of $0.3 million and a realized gain of $0.1 million on the contracts, respectively, which was recorded in interest and other income (expense), net in the Company’s Condensed Consolidated Statements of Operations and Comprehensive Income. For the six months ended June 30, 2016, ~~and 2015,~~ the Company recognized a realized gain of ~~$8,000~~$0.4 million and a realized loss of ~~$0.6~~$0.3 million on the contracts, respectively, which was recorded in other income (expense), net in the Company’s Statements of Operations and Comprehensive Income. For the six months ended June 30, 2017 and 2016, the Company recognized a realized gain of $0.5 million and $8,000 on the contracts, respectively, which was recorded in other income (expense), net in the Company’s Statement of Operations and Comprehensive Income.

The Company carries these derivatives financial instruments on its Consolidated Balance Sheets at their fair values. The ~~Company’s~~Company’s foreign currency forward contracts are classified as Level 2 because it is not actively traded and the valuation inputs are based on quoted prices and market observable data of similar instruments. As of June 30, 2017, the Company had one outstanding forward contract with a notional amount of $7.7 million and recorded $48,000 other current liabilities associated with this outstanding forward contract. As of December 31, 2016, the Company had one outstanding forward contract with a notional amount of $7.1 million and recorded $28,000 other current liabilities associated with this outstanding forward contract. As of December 31, 2015, the Company had one outstanding forward contract with a notional amount of $6.7$6.9 million and had recorded ~~$62,000~~$15,000 other current liabilities associated with the outstanding forward contract.

9. 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 $0.6 million ~~and $0.5 million~~ for the both three months ended June 30, ~~2016~~2017 and ~~2015,~~2016, respectively. Rent expense was ~~$1.2~~$1.1 million and ~~$1.0~~$1.2 million for the six months ended June 30, ~~2016~~2017 and ~~2015.~~2016.

Future minimum lease payments under noncancelable operating leases at June 30, ~~2016,~~2017, are as follows (in thousands):

Period Ending June 30,	Amount
2017 (remaining six months)	$	936
2018		1,329
2019		448
2020		381
2021		297
2022 and thereafter		75
Total future minimum lease payments	$	3,466

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 90 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 June 30, 2017, total outstanding purchase obligations were $8.1 million, which are primarily due within the next 12 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.

Period Ending June 30,

Amount

2016 (remaining six months)
$ 1,028
2017
1,733
2018
1,087
2019
264
2020
195
2021 and thereafter
61
Total future minimum lease payments
$ 4,368

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 FASB requirements. ~~During the reported period,~~As of June 30, 2017, the Company was not party to any material legal proceedings, thus no loss was probable and no amount was ~~accrued at June 30, 2016.~~accrued.

10. SUBSEQUENT EVENT

On July 11, 2017, the Company completed the transaction with Realtime Performance Europe B.V. (doing business as Kinesys Software), a Dutch provider of automation software to the semiconductor industry, to acquire certain assets from Kinesys Software for approximately $4.5 million, plus the assumption of the assumed liabilities. Further, up to an additional $0.6 million of earn-out in cash would be payable upon the completion of certain milestones. The Company is reviewing information surrounding the determination of the fair values of assets acquired and liabilities assumed.

Item 2. ~~Management’s~~Management’s Discussion and Analysis of Financial Condition and Resultsof Operations

Forward-Looking Statements

The following discussion of our financial condition and results of operations contains forward-looking statements within the meaning of Section 27A of the Securities Act of 1933 and Section 21E of the Securities Exchange Act of 1934. All statements other than statements of historical fact may be forward-looking statements. In some cases, you can identify forward-looking statements by terminology such as “may,” “could,” “should,” “expect,” “plan,” “anticipate,” “believe,” “estimate,” “predict,” “potential”, “target” or “continue,” the negative effect of terms like these or other similar expressions. Any statement concerning future financial performance (including future revenues, earnings or growth rates), ongoing business strategies or prospects, and possible actions taken by us or our subsidiaries, which may be provided by us are also forward-looking statements. These forward-looking statements are only predictions. Forward-looking statements are based on current expectations and projections about future events and are inherently subject to a variety of risks and uncertainties, many of which are beyond our control, which could cause actual results to differ materially from those anticipated or projected. All forward-looking statements included in this document are based on information available to us on the date of filing and we further caution investors that our business and financial performance are subject to substantial risks and uncertainties. We assume no obligation to update any such forward-looking statements. In evaluating these statements, you should specifically consider various factors, including the risk factors set forth ~~in Item 1A of this Quarterly Report on Form 10-Q as well as~~ in Item 1. “Business” and Item 7. “Management’s Discussion and Analysis of Financial Condition and Results of Operations” in our Annual Report on Form 10-K for the year ended December 31, ~~2015,~~2016, filed with the Securities and Exchange Commission on March ~~1, 2016.~~8, 2017. All references to “we”, “us”, “our”, “PDF”, “PDF Solutions” or “the Company” refer to PDF Solutions, Inc.

Overview

We analyze our ~~customers’~~customers’ IC design and manufacturing processes to identify, quantify, and correct the issues that cause yield loss to improve our customers’ profitability by improving time-to-market, increasing yield and reducing total design and manufacturing costs. We package our solutions in various ways to meet our customers’ specific business and budgetary needs, each of which provides us various revenue streams. We receive a mix of fixed fees and variable, performance-based fees for the vast majority of our yield improvement solutions. The fixed fees are typically reflective of the length of time and the resources needed to characterize a customer’s manufacturing process and receive preliminary results of proposed yield improvement suggestions. The variable fee, or what we call Gainshare, usually depends on our achieving certain yield targets by a deadline. Variable fees are currently typically tied to wafer volume on the node size of the manufacturing facility where we performed the yield improvement solutions. We receive license fees and service fees for related installation, integration, training, and maintenance and support services for our software that we license on a stand-alone basis.

Industry Trend

Consistent with the trend since 2010, we expect that the largest logic foundries will continue to invest significantly in leading edge nodes and capacity throughout ~~2016.~~2017. Leading foundries continue to invest in new technologies such as multi-patterned lithography and 3-D transistor ~~architecture, which~~architecture. In addition, China’s investment in semiconductors should accelerate the growth of the industry in the next few years. These provide opportunities to increase our business.

~~The capacity~~Capacity utilization for 28nm logic thus far in 2017 has been lower overall, and mixed across foundries. We believe that industry 28nm utilization will increase during the remainder of 2017, and additional China 28nm production. 14nm logic production is also expected to increase in 2017. We expect our ~~customers on 28nm declined during 2015, which caused~~Gainshare results to be consistent with those general market trends. Gainshare revenue will continue to fluctuate quarter to quarter despite these utilization trends as our Gainshare revenue depends on many factors, including the average selling price of wafers subject to ~~decline significantly in the same period. Although capacity utilization improved at the end of 2015~~Gainshare and ~~the first half of 2016, we believe that 28nm capacity utilization may not continue to increase substantially (or at all) for 2016, which would have a negative impact on our Gainshare revenue.~~volume.

Generally, the demand for consumer electronics and communications devices continues to drive technological innovation in the semiconductor industry as the need for products with greater performance, lower power consumption, reduced costs and smaller size continues to grow with each new product generation. In addition, advances in computing systems and mobile devices have fueled demand for higher capacity memory chips. To meet these demands, IC manufacturers and designers are constantly challenged to improve the overall performance of their ICs by designing and manufacturing ICs with more embedded applications to create greater functionality while lowering cost per transistor. As a result, both logic and memory manufacturers have migrated to more and more advanced manufacturing nodes, capable of integrating more devices with higher performance, higher density, and lower power. As this trend continues, companies will continually be challenged to improve process capabilities to optimally produce ICs with minimal random and systematic yield loss, which is driven by the lack of compatibility between the design and its respective manufacturing process. We believe that as volume production of deep submicron ICs continues to grow, the difficulties of integrating IC designs with their respective processes and ramping new manufacturing processes will create a greater need for products and services like ours that address the yield loss and escalating cost issues the semiconductor industry is facing today and will face in the future.

Customer Contracts

Although a substantial portion of our total revenues are concentrated in a small number of customers, the total revenues for each of these customers in any period is the result of Design-to-silicon-yield solutions and Gainshare performance incentives revenues recognized in the period under multiple, separate contracts, with no interdependent performance obligations. These contracts were all entered into in the ordinary course of our business and contain general terms and conditions that are standard across most of our yield improvement solutions customers, including providing services typically targeted to one manufacturing process node, for example the 28 or 20 nanometer node. Fluctuations in future results may occur if any of these customers renegotiate pre-existing contractual commitments due to adverse changes in their own business. See the additional discussion in Part I, Item 1, ~~"Customers,"~~“Customers,” on page 9 of our Annual Report on Form 10-K for the year ended December 31, ~~2015,~~2016, and in Item 1A, ~~"Risk~~“Risk Factors,"” on pages 1213 through 1920 of our Annual Report on Form 10-K for the year ended December 31, ~~2015,~~2016, for related information on the risks associated with customer concentration and Gainshare performance incentives revenue.

Financial Highlights

Financial highlights for the three months ended June 30, ~~2016,~~2017, were as follows:

Total revenues for the three months ended June 30, 2016, were $26.7 million, an increase of $3.5 million, or 15%, compared to $23.2 million for the three months ended June 30, 2015. Design-to-silicon-yield solutions revenue for the three months ended June 30, 2016, was $20.6 million, an increase of $6.4 million, or 45%, when compared to Design-to-silicon yield solutions revenue of $14.2 million for the three months ended June 30, 2015. The increase in Design-to-silicon-yield solutions was primarily the result of more billable hours to revenue-generating projects in the period due to increased business activity and an increase in the revenue from our Exensio big data solution. Gainshare performance incentives revenue for the three months ended June 30, 2016, was $6.1 million, a decrease of $2.9 million, or 32%, compared to $9.1 million for the three months ended June 30, 2015. The decrease in revenue from Gainshare performance incentives was primarily the result of lower net volumes reported at 28nm engagements.

	•	Total revenues for the three months ended June 30, 2017, were $24.3 million, a decrease of $2.4 million, or 9%, compared to $26.7 million for the three months ended June 30, 2016. Design-to-silicon-yield solutions revenue for the three months ended June 30, 2017, was $16.5 million, a decrease of $4.1 million, or 20%, when compared to Design-to-silicon yield solutions revenue of $20.6 million for the three months ended June 30, 2016. The decrease in Design-to-silicon-yield solutions was primarily due to a delay in purchases by new and existing customers. Gainshare performance incentives revenue for the three months ended June 30, 2017, was $7.8 million, an increase of $1.7 million, or 27%, compared to $6.1 million for the three months ended June 30, 2016. The increase in revenue from Gainshare performance incentives was primarily the result of higher Gainshare from 14nm volumes, partially offset by lower Gainshare from 28nm volumes.

	•	Net income for the three months ended June 30, ~~2016,~~2017 was ~~$2.2~~$0.2 million, compared to net income of $2.1 million for the three months ended June 30, ~~2015.~~2016. The decrease in net income was primarily attributable to a $3.1 million decrease in gross margin due to the lower revenues and an increase in cost of design-to-silicon-yield solutions and a $1.3 million increase in operating expense, primarily driven by the continued activity related to our development of our Design-For-Inspection (DFI) solution, offset by a $2.4 million decrease in tax provision primarily due to the recognition of excess tax benefits related to employee stock compensation as a result of the adoption of ASU 2016-09 as well as the decrease in level of income.


	•	Net income per basic and diluted share was ~~$0.07~~$0.01 for the three months ended June 30, ~~2016, the same~~2017, as compared to net income per basic and diluted share of $0.07 for the three months ended June 30, ~~2015.~~2016.

Financial highlights for the six months ended June 30, ~~2016,~~2017, were as follows:

Total revenues for the six months ended June 30, ~~2016,~~2017, were ~~$51.8~~$48.6 million, ~~an increase~~a decrease of ~~$1.7~~$3.2 million, or 3%6%, compared to ~~$50.0~~$51.8 million for the six months ended June 30, ~~2015.~~2016. Design-to-silicon-yield solutions revenue for the six months ended June 30, ~~2016,~~2017, was ~~$39.2~~$36.2 million, ~~an increase~~a decrease of ~~$6.8~~$3.0 million, or ~~21%~~8%, when compared to Design-to-silicon yield solutions revenue of ~~$32.3~~$39.2 million for the six months ended June 30, ~~2015.~~2016. The ~~increase~~decrease in Design-to-silicon-yield solutions was primarily ~~the result of more billable hours to revenue-generating projects in the period~~ due to ~~increased business activity~~a delay in purchases by new and ~~an increase in the revenue from our Exensio big data solution.~~existing customers. Gainshare performance incentives revenue for the six months ended June 30, ~~2016,~~2017, was ~~$12.6~~$12.4 million, a decrease of ~~$5.1~~$0.2 million, or ~~29%~~2%, compared to ~~$17.7~~$12.6 million for the six months ended June 30, ~~2015.~~2016. The decrease in revenue from Gainshare performance incentives was primarily the result of lower ~~net volumes reported~~Gainshare at 28nm ~~engagements.~~ volumes, not yet fully offset by higher Gainshare at 14nm volumes .

•

Net income for the six months ended June 30, ~~2016,~~2017, was ~~$4.3~~$0.7 million, compared to ~~$8.1~~$4.2 million for the six months ended June 30, ~~2015.~~2016. The decrease in net income was primarily attributable to a ~~$0.4~~$5.1 million decrease in gross margin due to the ~~mix shift between Design-to-silicon yield~~lower revenues, an increase in cost of design-to-silicon-yield solutions, and ~~Gainshare performance incentive revenue,~~ a ~~$5.6~~$3.0 million increase in operating expense, ~~which was~~ primarily driven by ~~a ramp up in~~ the ~~development~~continued activity related to our ~~Design-For-Inspection (DFI)~~development of our DFI solution, ~~initiative, an $0.4 million unfavorable change in interest and other income (expense),~~ offset by ~~the $2.6~~a $4.8 million decrease in tax provision primarily due to ~~lower~~the recognition of excess tax benefits related to employee stock compensation as a result of the adoption of ASU 2016-09 as well as the decrease in level of ~~taxable~~ income.

•

Net income per basic and diluted share was ~~$0.14 and $0.13, respectively,~~$0.02 for the six months ended June 30, ~~2016,~~2017, compared to net income per basic and diluted share of ~~$0.26 and $0.25, respectively,~~$0.13 for the six months ended June 30, ~~2015.~~2016.

Critical Accounting Policies

There were no significant changes in our critical accounting policies. Please refer to ~~Management’s~~Management’s Discussion and Analysis of Financial Condition and Results of Operations contained in Part II, Item 7 of our Annual Report on Form 10-K for the year ended December 31, ~~2015.~~2016. The following is a brief discussion of the more significant accounting policies and methods that we use.

General

Our discussion and analysis of our financial conditions, results of operations and cash flows are based on our consolidated financial statements, which have been prepared in conformity with accounting principles generally accepted in the United States of America. Our preparation of these consolidated financial statements requires us to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the dates of the financial statements and the reported amounts of revenues and expenses during the reporting periods. We based our estimates on historical experience and on various other assumptions that we believe to be reasonable under the circumstances. The most significant estimates and assumptions relate to revenue recognition, stock-based compensation and the realization of deferred tax assets. Actual amounts may differ from such estimates under different assumptions or conditions.

Revenue Recognition

We derive ~~revenue~~revenues from two sources: Design-to-silicon-yield ~~solutions, which include services and software licenses,~~Solutions and Gainshare performance incentives.

~~Design-to-Silicon-Yield Solutions~~ Design-to-silicon-yield solutions — ~~Revenue~~Revenues that isare derived from Design-to-silicon-yield solutions ~~comes~~come from services and software and hardware licenses. We recognize revenue for each element of Design-to-silicon-yield solutions as follows:

We generate a significant portion of our 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–~~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. If we do not accurately estimate the resources required or the scope of work to be performed, or do not manage the projects properly within the planned period of time or satisfy our obligations under contracts, resulting contract margins could be materially different than those anticipated when the contracts were executed. Any such reductions in contract margin could have a material negative impact on our operating results. Revenue under ~~certain~~ time and materials contracts for solution implementation services isare recognized as the services are performed.

On occasion, we license our software products as a component of our ~~fixed price~~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, ~~at each customer's option~~if applicable, over the license term. The amount of product and service revenue recognized in a given period is affected by ~~our~~the Company’s judgment as to whether an arrangement includes multiple deliverables and, if so, our determination of the fair value of each deliverable. In general, vendor-specific objective evidence of selling price (“VSOE”) does not exist for our solution implementation services and software products and because our services and products include our unique technology, we are not able to determine third-party evidence of selling price (“TPE”). Therefore, in such circumstances we use best estimated selling prices (“BESP”) in ~~our~~the allocation of arrangement consideration. In determining BESP, we apply significant judgment as we weigh a variety of factors, based on the facts and circumstances of the arrangement. We typically arrive 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 ~~fair value.~~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, we also license our DFI system as a separate component of fixed-price service contracts. We allocate revenue to all deliverables based on their relative selling prices. We currently do not have VSOE for our DFI system, thus we use either TPE or BESP in the allocation of arrangement consideration.

We defer 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. We recognize 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. We also defer 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 reporting period, we evaluate its deferred costs for their probable recoverability. We recognize impairment of deferred costs when it is determined that the costs no longer have future benefits and are no longer recoverable.

We also license our software products separately from ~~our~~ solution ~~implementation services.~~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 ~~(1)~~(l) persuasive evidence of an arrangement exists, (2) delivery has occurred, (3) the fee is fixed or determinable, (4) collectability is probable, and (5) 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 our fixed price solution implementations), installation, and training, revenue is allocated to each element of a transaction based upon its fair value as determined by our VSOE and such services are recorded as services ~~revenues.~~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 our 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~~We are unable to establish VSOE of fair value for maintenance services that are generally bundled with term licenses. In these cases, ~~the Company recognizes~~we recognize revenue ratably over the term of the contract. For multiple-element arrangements containing non-software services, the Company: (1) determines whether each element constitutes a separate unit of accounting; (2) determines the fair value of each element using the selling price hierarchy of VSOE, TPE or BESP, as applicable; and (3) 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, we allocate 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)~~software-as-a-service (or SaaS) that ~~allows~~allow for the use of a hosted software product or service over a contractually determined period of time without taking possession of software isare accounted for as ~~a subscription~~subscriptions and recognized as revenue ratably over the coverage period beginning on the date the service is ~~first~~ made available to customers.

Gainshare Performance Incentives — When we enter into a contract to provide yield improvement services, the contract usually includes two components: (1) a fixed fee for performance by us of services delivered over a specific period of time; and (2) a Gainshare performance ~~incentives~~incentive component where the customer may pay a contingent variable fee, usually after the fixed fee period has ended. ~~Revenues~~Revenue derived from Gainshare performance incentives ~~represent~~represents profit sharing and performance incentives earned contingent upon our 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 no cost to us. Due to the uncertainties surrounding attainment of such operational levels, we recognize Gainshare performance incentives ~~revenues~~revenue (to the extent of completion of the related solution implementation ~~services)~~contract) upon receipt of performance reports or other related information from ~~our customers~~the customer supporting the determination of amounts and probability of collection. Gainshare performance incentives revenue is dependent on many factors which are outside our control, which can include among others, continued production of the related ICs by our customers, sustained yield improvements by our customers, and our ability to enter into new Design-to-silicon-yield solutions contracts containing provisions for Gainshare performance incentives.

Stock-Based Compensation

Stock-based compensation is estimated at the grant date based on the ~~award’s~~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.

We have 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 our common stock over the most recent period commensurate with the estimated expected life of 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 stock options.

Income Taxes

We are required to assess the likelihood that our deferred tax assets will be recovered from future taxable income and if we believe that they are not likely to be realizable before the expiration dates applicable to such assets then, to the extent we believe that recovery is not likely, establish a valuation allowance. Changes in the net deferred tax assets, less offsetting valuation allowance, in a period are recorded through the income tax provision (benefit)in the condensed consolidated statements of operations. The valuation allowance was approximately ~~$6.4~~$6.5 million and ~~$6.2~~$6.8 million as of June 30, ~~2016~~2017 and December 31, ~~2015,~~2016, respectively, which was related to California R&D tax credits and California net operating losses related to an acquisition that we currently do not believe to be more likely than not to be ultimately realized. If we conclude at a future financial reporting period that there has been a change in our ability to realize our California R&D credit and net operating loss carry forward deferred tax assets, and it is at such time no longer “more–likely-than-not” that we will realize the tax credits before applicable expiration dates, our tax provision will increase in the period in which we make such determination.

Our income tax calculations are based on application of the respective U.S. federal, state or foreign tax law. Our tax filings, however, are subject to audit by the respective tax authorities. Accordingly, we recognize tax liabilities based upon our 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. At June 30, 2017, no deferred taxes have been provided on undistributed earnings of approximately $6.7 million from the Company’s international subsidiaries since these earnings have been, and under current plans will continue to be, permanently reinvested outside the United States. It is not practicable to determine the amount of the unrecognized tax liability at this time.

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.

Goodwill and Intangible Assets

We record 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. We perform an annual impairment assessment of 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 no further testing is required. If further testing is required, we perform 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, we have determined that we have one reporting unit. There was no impairment of goodwill for the period ended June 30, ~~2016.~~2017.

Our long-lived assets, excluding goodwill, consist of property and equipment and intangible assets. We periodically review our long-lived assets for impairment. For assets to be held and used, we initiate our 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. During the three ~~and six~~ months ended June 30, ~~2016,~~2017, there was no impairment related to our long-lived assets.

Recent Accounting Pronouncements and Accounting Changes

See Note 2 of “Notes to Condensed Consolidated Financial Statements (Unaudited)” of this Quarterly Report on Form 10-Q for a description of recent accounting pronouncements and accounting changes, including the expected dates of adoption and estimated effects, if any, on our consolidated financial statements.

Results of Operations

The following table sets forth, for the periods indicated, the percentage of total revenues represented by the line items reflected in our condensed consolidated statements of operations:

	Three Months Ended June 30,						Six Months Ended June 30,						Three Months Ended June 30,						Six Months Ended June 30,
	2016			2015			2016			2015			2017			2016			2017			2016
Revenues:
Design-to-silicon-yield solutions		77	%		61	%		76	%		65	%		68	%		77	%		74	%		76	%
Gainshare performance incentives		23			39			24			35			32			23			26			24
Total revenues		100	%		100	%		100	%		100	%		100	%		100	%		100	%		100	%

Costs of design-to-silicon-yield solutions		40			43			40			37			47			40			47			40
Amortization of acquired technology		—			—			—			—			—			—			—			—
Total cost of design-to-silicon-yield solutions														47			40			47			40
Gross profit		60			57			60			63			47			60			53			60
Operating expenses:
Research and development		27			19			26			17			30			27			30			26
Selling, general and administrative		19			22			20			20			26			19			25			20
Amoritization of other acquired intangible assets		—			—			—			—			—			—			—			—
Total operating expenses		46			41			46			37			56			46			55			46
Income from operations		14			16			14			26
Income (loss) from operations														(3	)		14			(2	)		14
Interest and other income (expense), net		—			—			(1	)		—			—			—			(1	)		(1	)
Income before taxes		14			16			13			26
Income tax provision		6			7			5			10
Income (loss) before taxes														(3	)		14			(3	)		13
Income tax provision (benefit)														(4	)		6			(4	)		5
Net income		8	%		9	%		8	%		16	%		1	%		8	%		1	%		8	%

Comparison of the Three Months Ended June 30, ~~2016~~2017 and ~~2015~~2016

	Three Months Ended June 30,				$			%			Three Months Ended June 30,							%
Revenues	2016		2015		Change			Change			2017		2016		Change			Change
(in thousands, except for percentages)
Design-to-silicon-yield solutions	$	20,574	$	14,159	$	6,415			45	%	$	16,500	$	20,574	$	(4,074	)		(20	)%
Gainshare performance incentives		6,114		9,051		(2,937	)		(32	)%		7,789		6,114		1,675			27	%
Total revenues	$	26,688	$	23,210	$	3,478			15	%	$	24,289	$	26,688	$	(2,399	)		(9	)%

Design-to-silicon-yield solutions. Design-to-silicon-yield solutions revenue is derived from services (including ~~solution implementations,~~services from yield solutions, design for inspection solutions, software support and maintenance, consulting, and training) and software and or system licenses, provided during our customer ~~yield improvement~~ engagements as well as during solution product sales. Design-to-silicon-yield solutions revenue ~~increased $6.4~~decreased $4.1 million for the three months ended June 30, ~~2016,~~2017, compared to the three months ended June 30, ~~2015,~~ 2016, primarily due to ~~an increase~~a delay in ~~the revenue from fixed fee integrated solutions, the result of more billable hours to revenue-generating projects in the period due to increased business activity~~purchases by new and ~~an increase in the revenue from our Exensio big data solution.~~existing customers. Our Design-to-silicon-yield solutions revenue may fluctuate in the future and is dependent on a number of factors, including the semiconductor industry’s continued acceptance of our solutions, the timing of purchases by existing and new customers, and our ability to attract new customers and penetrate new markets, ~~including photovoltaic and LED,~~ and further penetration of our current customer base. Fluctuations in future results may also occur if any of our significant customers renegotiate pre-existing contractual commitments due to adverse changes in their own business or, in the case of a time and materials contract, may take advantage of contractual provisions that permit the suspension of contracted work for a period if their business experiences a financial hardship.

Gainshare Performance Incentives. Gainshare performance incentives revenues represent profit sharing and performance incentives earned contingent upon our customers reaching certain defined operational levels. Revenue derived from Gainshare performance incentives ~~decreased $2.9~~increased $1.7 million for the three months ended June 30, ~~2016,~~2017, compared to the three months ended June 30, ~~2015.~~2016. The ~~decrease~~increase was ~~primarily~~ the result of ~~lower net~~higher Gainshare from 14nm volumes, ~~reported at older nodes, primarily~~partially offset by a decrease in Gainshare from 28nm ~~engagement.~~volumes. Our Gainshare performance incentives revenue may continue to fluctuate from period to period. Gainshare performance incentives revenue is dependent on many factors that are outside our control, including among others, continued production of ICs by our customers at facilities at which we generate ~~gainshare,~~Gainshare, sustained yield improvements by our customers, and our ability to enter into new Design-to-silicon-yield solutions contracts containing ~~provisions for~~ Gainshare performance incentives.

	Three Months Ended June 30,				$		%			Three Months Ended June 30,						%
Costs of Design-to-silicon-yield solutions	2016		2015		Change		Change			2017		2016		Change		Change
(in thousands, except for percentages)
Direct costs of Design-to-silicon-yield solutions	$	10,558	$	9,888	$	670		7	%	$	11,283	$	10,558	$	725		7	%
Amortization of acquired technology		96		—		96		—	%		96		96		—		—-	%
Total costs of Design-to-silicon-yield solutions	$	10,654	$	9,888	$	766		8	%	$	11,379	$	10,654	$	725		7	%

Costs of Design-to-silicon-yield solutions. Costs of Design-to-silicon-yield solutions consist of costs incurred to provide and support our services, ~~and~~ costs recognized in connection with licensing our ~~software. Services~~software, and amortization of acquired technology. Direct costs of Design-to-silicon-yield solutions consist of service and software licenses costs. Service costs consist of material, employee compensation and related benefits, overhead costs, travel and facilities-related costs. Software license costs consist of costs associated with licensing third-party software used by the Company in providing services to our customers in solution engagements, or sold in conjunction with our software products. Direct costs of Design-to-silicon-yield solutions increased $0.7 million for the three months ended June 30, ~~2016 increased $0.7 million~~2017, compared to the three months ended June 30, ~~2015,~~2016, primarily due to a ~~$0.6~~$0.5 million increase in ~~personnel~~personnel-related cost driven by hiring in Asia and world-wide merit increases, a $0.1 million increase in subcontractor expense, and a ~~$0.1~~$0.3 million increase in depreciation expense of test equipment, partially offset by a $0.1 million ~~increase~~decrease in travel expense and a $0.1 million ~~increase~~decrease in facility ~~cost, offset by a $0.3 million decrease in equipment~~ costs. Amortization of acquired technology for the three months ended June 30, 2017 and 2016 ~~was due to~~remained the ~~amortization of acquired technology from the Syntricity acquisition.~~same at $0.1 million.

	Three Months Ended									Three Months Ended
	June 30,				$		%			June 30						%
Research and Development	2016		2015		Change		Change			2017		2016		Change		Change
(in thousands, except for percentages)
Research and development	$	7,060	$	4,437	$	2,623		59	%	$	7,276	$	7,060	$	216		3	%

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, ~~and~~ facilities cost allocations, and stock-based compensation charges. Research and development expenses increased ~~$2.6~~$0.2 million for the three months ended June 30, ~~2016,~~2017, compared to the three months ended June 30, ~~2015,~~2016, primarily due to a ~~$1.2~~$0.3 million personnel-related expense due to higher headcount and world-wide merit increases, ~~a $1.0 million increase in subcontractor expense, a $0.2 million increase in facility expense,~~offset by a $0.1 million ~~increase~~decrease in ~~lab supplies, and a $0.1 million increase in travel~~subcontractor expense. The increased investment in research and development is primarily driven by ~~a ramp up in the~~continued development activity related to our DFI ~~solution initiative and is expected to continue during 2016.~~solution. We anticipate our expenses in research and development will fluctuate in absolute dollars from period to period as a result of cost control initiatives and the timing of ~~when we hire personnel as a result of the size and the timing of~~ product development ~~projects.~~projects and revenue generating activity requirements.

	Three Months Ended										Three Months Ended
	June 30,				$			%			June 30,				$		%
Selling, General and Administrative	2016		2015		Change			Change			2017		2016		Change		Change
(in thousands, except for percentages)
Selling, general and administrative	$	5,094	$	5,216	$	(122	)		(2	)%	$	6,195	$	5,094	$	1,101		22	%

Selling, General andAdministrative. Selling, general and administrative expenses consist primarily of compensation and benefits for sales, marketing and general and administrative personnel, legal and accounting services, marketing communications, travel and facilities cost allocations, and stock-based compensation charges. Selling, general and administrative expenses ~~decreased $0.1~~increased $1.1 million for the three months ended June 30, ~~2016,~~2017, compared to the three months ended June 30, ~~2015,~~2016, primarily due to a ~~$0.5~~$0.3 million ~~decrease~~increase in ~~acquisition-related costs related to Syntricity acquisition in the prior year, a $0.1 million decrease in provision for doubtful accounts, offset by~~personnel-related expense due world-wide merit increases and hiring of an executive, a $0.4 million increase in ~~personnel-related~~accounting and legal expense, asprimarily a result of the new system implementation and increased ~~headcount from Syntricity acquisition, hiring~~legal activities related to Kinesys asset purchase transactions, a $0.3 million increase in ~~our softwaresolution business and world-wide merit increases,~~allowance for doubtful account due to an increase in accounts receivable balance and a $0.1 million increase in ~~subcontractor costs.~~travel expense. We anticipate our selling, general and administrative expenses will fluctuate in absolute dollars from period to period as a result of cost control initiatives and to support increased selling efforts in the future.

Three Months Ended

June 30,
$
%

Amortization of Other Acquired Intangible Assets

2016

2015

Change

Change

(In thousands, except for percentages)

Amortization of other acquired intangible assets
$ 117 $ — $ 117 —
%

Amortization of Other Acquired Intangible Assets. Amortization of other acquired intangible assets consists of amortization of intangibles acquired as a result of certain business combinations. The amortization of other acquired intangible assets for the three months ended June 30, ~~2016 is related~~2017 remained flat at $0.1 million compared to ~~amortization of acquired intangible assets from~~ the ~~Syntricity acquisition.~~ three months ended June 30, 2016.

Three Months Ended

June 30,
$
%

Interest and Other Income (Expense), Net

2016

2015

Change

Change

(in thousands, except for percentages)

Interest and other income (expense), net
$ (51
)
$ 52 $ (103
)
(198
)%

Interest and Other Income (expense), net. ~~Interest~~The decrease in interest and other income (expense), net ~~changed $0.1 million~~from a $51,000 income for the three months ended June 30, 2016 ~~compared~~ to a $27,000 expense for the three months ended June 30, ~~2015. The change~~2017 was primarily due to foreign exchange rate movements.

Three Months Ended

June 30,
$
%

Income Tax Provision

2016

2015

Change

Change

(in thousands, except for percentages)

Income tax provision
$ 1,498 $ 1,572 $ (74
)
(5
)%

	Three Months Ended
	June 30,					$			%
Income Tax Provision (benefit)	2017			2016		Change			Change
(in thousands, except for percentages)
Income tax provision (benefit)	$	(815	)	$	1,579	$	(2,394	)		(152	)%

Income Tax ~~Provision.~~Provision (benefit). ~~Income~~The decrease in income tax provision ~~decreased $0.1~~(benefit) from $1.6 million expense for the three months ended June 30, 2016 ~~compared~~ to $0.8 million benefit for the three months ended June 30, ~~2015, primarily due to~~2017 was primarily due to the ~~permanent reinstatement of~~increase in excess tax benefits related to employee stock compensation as well as the ~~U.S. federal research tax credit.~~decrease in income.

Comparison of ~~the~~the Six Months Ended June 30, ~~2016~~2017 and ~~2015~~2016

	Six Months Ended										Six Months Ended
	June 30,				$			%			June 30,				$			%
Revenues	2016		2015		Change			Change			2017		2016		Change			Change
(In thousands, except for percentages)
Design-to-silicon-yield solutions	$	39,152	$	32,311	$	6,841			21	%	$	36,198	$	39,152	$	(2,954	)		(8	)%
Gainshare performance incentives		12,617		17,716		(5,099	)		(29	)%		12,380		12,617		(237	)		(2	)%
Total	$	51,769	$	50,027	$	1,742			3	%	$	48,578	$	51,769	$	(3,191	)		(6	)%

Design-to-Silicon-Yield Solutions. Design-to-silicon-yield solutions revenue ~~increased $6.8~~decreased $3.0 million for the six months ended June 30, ~~2016~~2017 compared to the six months ended June 30, ~~2015,~~2016, primarily due to ~~an increase in the revenue from fixed fee integrated solutions, the result~~timing of ~~more billable hours to revenue-generating projects in the period due to increased business activity~~purchases by new and ~~an increase in the revenue from our Exensio big data solution.~~existing customers.

Gainshare Performance Incentives. Revenue derived from ~~gainshare~~Gainshare performance incentives decreased ~~$5.1~~$0.2 million for the six months ended June 30, ~~2016~~2017 compared to the six months ended June 30, ~~2015. The decrease was~~2016, primarily ~~the result of~~due to lower ~~net~~Gainshare from 28nm volumes, ~~reported at 28nm engagements.~~not yet fully offset by higher Gainshare from 14nm volumes.

	SixMonths Ended June 30,				$		%			Six Months Ended June 30,				$		%
Costs of Design-to-silicon-yield solutions	2016		2015		Change		Change			2017		2016		Change		Change
(in thousands, except for percentages)
Direct costs of Design-to-silicon-yield solutions	$	20,668	$	18,692	$	1,976		11	%	$	22,618	$	20,668	$	1,950		9	%
Amortization of acquired technology		192		—		192		—	%		192		192		—		—	%
Total costs of Design-to-silicon-yield solutions	$	20,860	$	18,692	$	2,168		12	%	$	22,810	$	20,860	$	1,950		9	%

Costs of Design-to-Silicon-Yield Solutions. ~~Direct costs~~Costs of Design-to-silicon-yield solutions increased $2.0 million for the six months ended June 30, ~~2016~~2017 compared to the six months ended June 30, ~~2015.~~2016. The increase was primarily due to a ~~$0.9~~$1.2 million increase in personnel-related costs, ~~driven by hiring~~primarily due to the increase in headcount in Asia, ~~and world-wide merit increases,~~ a ~~$0.2~~$0.5 million increase in depreciation expense related to our test equipment, and a $0.2 million increase in ~~facility expense, a $0.1 million increase in~~ subcontractor ~~expense, a $0.1 million increase in travel expense, offset by a $0.1 million decrease in equipment costs.~~expense. Amortization of acquired technology for the three months ended June 30, ~~2016 was due~~2017 remained the same at $0.2 million compared to amortization for the ~~amortization of acquired technology from the Syntricity acquisition.~~three months ended June 30, 2016.

	Six Months Ended									Six Months Ended
	June 30,				$		%			June 30,				$		%
Research and Development	2016		2015		Change		Change			2017		2016		Change		Change
(In thousands, except for percentages)
Research and development	$	13,371	$	8,525	$	4,846		57	%	$	14,557	$	13,371	$	1,186		9	%

Research and Development.Research and development expenses increased ~~$4.8~~$1.2 million for the six months ended June 30, ~~2016~~2017 compared to the six months ended June 30, ~~2015,~~2016, primarily due to a ~~$2.6~~$0.6 million increase in personnel-related expense, ~~due to~~ a ~~higher headcount and world-wide merit increases, a $1.4~~$0.4 million increase in subcontractor expenses, and a ~~$0.5 million increase in facility expense,~~ $0.2 million increase in ~~lab supplies and $0.1 million increase in travel~~depreciation expense. The increased investment in research and development is primarily driven by ~~a ramp up in the~~continued development activity related to our DFI ~~solution initiative and is expected to continue during 2016.~~solution.

	Six Months Ended									Six Months Ended
	June 30,				$		%			June 30,				$		%
Selling, General and Administrative	2016		2015		Change		Change			2017		2016		Change		Change
(In thousands, except for percentages)
Selling, general and administrative	$	10,218	$	9,672	$	546		6	%	$	12,095	$	10,218	$	1,877		18	%

Selling, General and Administrative. Selling, general and administrative expenses increased ~~$0.5~~$1.9 million for the six months ended June 30, ~~2016~~2017 compared to the six months ended June 30, ~~2015,~~2016, primarily due to a ~~$0.8~~$0.5 million increase in personnel-related expense as a result of ~~increased headcount from Syntricity acquisition in the third quarter of fiscal year of 2015, hiring in our software solution business and~~ world-wide merit increases and hiring of an executive, a ~~$0.1 million increase in facility expense, a $0.1 million increase in subcontractor expense and a $0.1~~$0.7 million increase in accounting and legal expense ~~offset by~~primarily a ~~$0.5~~result of the new system implementation and increased legal activities related to Kinesys asset purchase transactions, a $0.2 million ~~decrease~~increase in ~~acquisition costs relating~~subcontractor expense, a $0.2 million increase in facility expense, a $0.2 million increase in allowance for doubtful account due to ~~the Syntricity acquisition~~an increase in ~~the prior year.~~accounts receivable balance, and a $0.1 million increase in travel expense.

Six Months Ended

June 30,
$
%

Amortization of Other Acquired Intangible Assets

2016

2015

Change

Change

(In thousands, except for percentages)

Amortization of other acquired intangible assets
$ 234 $ — $ 234 —
%

~~The amortization~~Amortization of other acquired intangible ~~assets~~for the six months ended June 30, 2017 decreased slightly compared to amortization for the six months ended June 30, 2016.

Interest and Other Income (Expense), Net. The decrease in interest and other income (expense), net from a $0.3 million expense for the six months ended June 30, 2016 ~~is related~~ to ~~amortization of acquired intangible assets from the Syntricity acquisition.~~

Six Months Ended

June 30,
$
%

Interest and Other Income (Expense), Net

2016

2015

Change

Change

(In thousands, except for percentages)

Interest and other income (expense), net
$ (287
)
$ 103 $ (390 ) (379
)%

~~Interest and Other Income (Expense), Net~~~~. Interest and other income (expense) changed $0.4~~a $0.2 million expense for the six months ended June 30, ~~2016 compared to the six months ended June 30, 2015. The change~~2017 was primarily due to foreign exchange rate movements.

	Six Months Ended										Six Months Ended
	June 30,				$			%			June 30,					$			%
Income Tax Provision	2016		2015		Change			Change			2017			2016		Change			Change
(In thousands, except for percentages)
Income tax provision	$	2,523	$	5,125	$	(2,602	)		(51	)%	$	(1,976	)	$	2,605	$	(4,581	)		(176	)%

Income Tax ~~Provision.~~Provision (benefit). ~~Income~~The decrease in income tax provision ~~decreased~~(benefit) from a $2.6 million expense for the six months ended June 30, 2016 ~~compared~~ to ~~six months ended June 30, 2015, primarily due to the permanent reinstatement of the U.S. federal research tax credit.~~

~~Liquidity and Capital Resources~~

~~Operating Activities~~

~~Cash flows provided by operating activities was $1.0~~a $2.0 million benefit for the six months ended June 30, 2016. This resulted from net income of $4.3 million, an adjustment of $6.1 million for non-cash charges and a cash decrease of $9.4 million reflected in the net change of operating assets and liabilities. Non-cash charges consisted2017 was primarily of stock-based compensation of $5.0 million, depreciation and amortization of $1.6 million, tax benefit from stock-based compensation of $0.8 million, amortization of acquired intangible assets of $0.4 million, and loss on disposal of property and equipment of $0.1 million, offset by excess tax benefit from stock-based compensation of $0.7 million and tax withholdings related to net share settlements of restricted stock awards and units of $1.1 million. Cash flow decreases resulting from the net change in operating assets and liabilities primarily consisted of a $1.2 million increase in accounts receivable, a $8.9 million increase in prepaid expense and other assets due to the increase in ~~the long-term unbilled portion of two of the Company's Design-to-silicon-yield solutions contracts, a $1.0 million decrease in billing in~~ excess ~~of recognized revenues, offset by a $0.6 million increase in accounts payable, a $0.3 million increase in accrued~~tax benefits related to employee stock compensation and related benefits, and a $1.0 million increase in deferred revenue. The $10.2 million combined cash flow decrease resulting from the increase in accounts receivable, the increase in deferred revenue, the increase in prepaid expense and other assets andas well as the decrease in ~~billings in excess of recognized revenues, was primarily due to the timing of billing milestones and payments received.~~

Cash flows provided by operating activities was $16.8 million for the six months ended June 30, 2015. This resulted from net income of $8.1 million, adjustment of $5.8 million for non-cash charges and a cash increase of $2.9 million reflected in the net change of operating assets and liabilities. Non-cash charges consisted primarily of stock-based compensation of $4.6 million, deferred taxes of $1.0 million, tax benefit related to stock-based compensation plan of $2.1 million, depreciation and amortization of $1.2 million, partially offset by excess tax benefit from stock-based compensation of $2.0 million and tax withholdings related to net share settlements of restricted stock awards and units of $1.0 million. Cash flow increases resulting from the net change in operating assets and liabilities primarily consisted of a $6.9 million decrease in accounts receivable, primarily driven by strong collections, a $1.8 million net increase in deferred revenue, offset by a $1.5 million decrease in accrued compensation and related benefits, driven by the payment of variable compensation during the period, and a $4.4 million decrease in prepaid expenses and other assets. The $8.7 million combined cash flow increase resulting from the decrease in accounts receivable and the increase in deferred revenue was primarily due to the timing of billing milestones and payments received.

~~Investing Activities~~income.

~~Cash flows used in investing activities of $5.1 million~~Liquidity and ~~$2.4 million for the six months ended June 30, 2016 and 2015, respectively, consisted of payments for capital expenditures, primarily test equipment.~~

~~Financing Activities~~

Cash flows provided by financing activities of $0.1 million for the six months ended June 30, 2016, consisted primarily of $0.8 million of proceeds from our Employee Stock Purchase Plan, $0.5 million of proceeds from the exercise of stock options, $0.7 million of excess tax benefit from stock-based compensation, offset by $1.8 million of cash used to repurchase 129,457 shares of our common stock at an average price of $14.24 per share.

Cash flows provided by financing activities of $1.8 million for the six months ended June 30, 2015, consisted primarily of $4.8 million of proceeds from the exercise of stock options, $0.7 million of proceeds from our Employee Stock Purchase Plan, $2.0 million of excess tax benefit from stock-based compensation, offset by $5.6 million of cash used to repurchase 319,712 shares of our common stock at an average price of $17.43 per share.

~~Liquidity~~Capital Resources

As of June 30, ~~2016,~~2017, our working capital, defined as total current assets less total current liabilities, was ~~$145.1~~$152.3 million, compared ~~with $148.8~~to $151.8 million as of December 31, ~~2015.~~2016. Cash and cash equivalents were ~~$122.2~~$109.0 million as of June 30, ~~2016,~~2017, compared to ~~$126.2~~$116.8 million as of December 31, ~~2015.~~2016. As of June 30, ~~2016~~2017 and December 31, ~~2015,~~2016, cash and cash equivalents held by our foreign subsidiaries were ~~$2.6~~$3.2 million and ~~$2.2~~$3.4 million, respectively. We believe that our existing cash resources and anticipated funds from operations will satisfy our cash requirements to fund our operating activities, capital expenditures and other obligations for the ~~foreseeable future.~~ next twelve months.

During six months ended June 30, 2017, cash provided by operating activities of $1.0 million was a result of $0.7 million of net income, non-cash adjustments to net income of $8.4 million and a cash decrease in the net change in operating assets and liabilities of $8.1 million. Non-cash charges consisted primarily of stock-based compensation of $5.8 million, depreciation and amortization of $2.3 million, amortization of acquired intangible assets of $0.4 million, and a provision for doubtful accounts of $0.1 million, partially offset by deferred taxes of $0.2 million. Cash flow decreases resulting from the net change in operating assets and liabilities primarily consisted of a $6.0 million increase in accounts receivable, mainly due to the slow payments from Asia customers, a $3.4 million increase in prepaid expense and other current assets, a $0.2 million decrease in accrued compensation and related benefits, and a $0.7 million of decrease in accrued and other liabilities, partially offset by a $0.9 million increase in accounts payable, a $0.4 million decrease in other non-current assets, a $0.7 million increase in deferred revenue, and a $0.3 million increase in billing in excess of recognized revenue. Cash flows used in investing activities of $5.0 million for the six months ended June 30, 2017, consisted of payments for capital expenditures, primarily test equipment. Cash flows used in financing activities of $3.9 million for the six months ended June 30, 2017, consisted of $4.8 million of cash used to purchase shares of our common stock, $1.9 million cash payments for taxes related to net share settlement of equity awards, offset by $1.8 million of proceeds from the exercise of stock options and $0.9 million of proceeds from our Employee Stock Purchase Plan.

During the six months ended June 30, 2016, cash generated from operating activities of $2.8 million was a result of $4.2 million of net income, non-cash adjustments to net income of $8.0 million and a cash decrease in the net change in operating assets and liabilities of $9.4 million. Non-cash charges consisted primarily of stock-based compensation of $5.0 million, depreciation and amortization of $1.6 million, deferred taxes of $1.0 million, amortization of acquired intangible assets of $0.4 million, and loss on disposal of property and equipment of $0.1 million, offset by $0.1 million reversal of doubtful accounts. Cash flow decreases resulting from the net change in operating assets and liabilities primarily consisted of a $1.2 million increase in accounts receivable, a $1.0 million increase in prepaid expense and other current assets, a $7.9 million increase in other non-current assets due to the increase in the long-term unbilled portion of the Company's Design-to-silicon-yield solutions contracts, a $1.0 million decrease in billing in excess of recognized revenues, and a $0.2 million decrease in accrued and other liabilities, offset by a $0.6 million increase in accounts payable, a $0.3 million increase in accrued compensation and related benefits, and a $1.0 million increase in deferred revenue. Cash flows used in investing activities of $5.1 million for the six months ended June 30, 2016, respectively, consisted of payments for capital expenditures, primarily test equipment. Cash flows used in financing activities of $1.7 million for the six months ended June 30, 2016, consisted primarily of $1.8 million of cash used to repurchase shares of our common stock, and $1.1 million of cash payments for taxes related to net share settlement of equity awards, offset by $0.5 million of proceeds from the exercise of stock options and $0.8 million proceeds from our Employee Stock Purchase Plan.

Off-Balance Sheet Agreements

We do not have any off-balance sheet arrangements, investments in special purpose entities or undisclosed borrowings or debt.

Contractual Obligations

The following table summarizes our known contractual obligations (in thousands) as of June 30, ~~2016:~~2017:

	Payments Due by Period														Payments Due by Period
Contractual Obligations(1)	2016 (remaining six months)		2017		2018		2019		2020		2021 and thereafter		Total
Contractual Obligations															2017 (remaining six months)		2018		2019		2020		2021		2022 and thereafter		Total
Operating lease obligations	$	1,028	$	1,733	$	1,087	$	264	$	195	$	61	$	4,368	$	936	$	1,329	$	448	$	381	$	297	$	75	$	3,466
Purchase obligations(1)																6,834		576		267		222		222		—		8,121
Total(2)															$	7,770	$	1,905	$	715	$	603	$	519	$	75	$	11,587

	(1)	Purchase obligations consist of agreements to purchase goods and services entered in the ordinary course of business.
	(2)	The contractual obligation table above excludes liabilities for uncertain tax positions of ~~$2.6~~$2.7 million, which are not practicable to assign to any particular years, due to the inherent uncertainty of the tax positions. See Note 5 of “Notes to Consolidated Financial Statements” for further discussion.

Item 3. Quantitative and Qualitative Disclosures ~~About~~about Market Risk

The following discusses our exposure to market risk related to changes in interest rates and foreign currency exchange rates. We do not currently own any equity investments, nor do we expect to own any in the foreseeable future. This discussion contains forward-looking statements that are subject to risks and uncertainties. Actual results could vary materially as a result of a number of factors.

Interest Rate Risk. As of June 30, ~~2016,~~2017, we had cash and cash equivalents of ~~$122.2~~$109.0 million. Cash and cash equivalents consisted of cash and highly liquid money market instruments. We would not expect our operating results or cash flows to be affected to any significant degree by the effect of a sudden change in market interest on our portfolio. A hypothetical increase in market interest rates of 100 basis points from the market rates in effect at June 30, ~~2016,~~2017, would cause the fair value of these investments to decrease by an immaterial amount which would not have significantly impacted our financial position or results of operations. Declines in interest rates over time will result in lower interest income and interest expense.

Foreign Currency and Exchange Risk. Certain of our payables for our international offices are denominated in the local currency, including the Euro, Yen and RMB. Therefore, a portion of our operating expenditures is subject to foreign currency risks. We enter into foreign currency forward contracts to reduce the exposure to foreign currency exchange rate fluctuations on certain foreign currency denominated monetary assets and liabilities. We do not use foreign currency forward contracts for speculative or trading purposes. We record these forward contracts at fair value. The counterparty to these foreign currency forward contracts is a large global financial institution that we believe is creditworthy, and therefore, we believe the credit risk of counterparty non-performance is not significant. 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 foreign currency denominated monetary assets and liabilities, which is also recorded in other income (expense), net. As of June 30, ~~2016,~~2017, we had one outstanding forward contract with a notional amount of ~~$7.1~~$7.7 million. The foreign currency exchange rate movement of plus-or-minus 10% will result in the change in fair value of this contract of plus-or-minus ~~$0.7~~$0.8 million.

Item 4. Controls and Procedures

Evaluation of Disclosure Controls and Procedures

Our management, with the participation of our principal executive officer and principal financial and accounting officer, evaluated the effectiveness of our ~~"disclosure~~“disclosure controls and ~~procedures"~~ procedures” as defined in Exchange Act Rules 13a-15(e) and 15d-15(e) as of June 30, ~~2016,~~2017, in connection with the filing of this Quarterly Report on Form 10-Q. Based on that evaluation as of June 30, ~~2016,~~2017, our principal executive officer and principal financial and accounting officer concluded that our disclosure controls and procedures were effective to ensure that information we are required to disclose in reports that we file or submit under the Exchange Act is recorded, processed, summarized and reported within the time periods specified in rules and forms of the SEC and accumulated and communicated to our management as appropriate to allow timely decisions regarding required disclosure.

Changes in Internal Control over Financial Reporting

There were no changes in the Company's internal control over financial reporting during the three months ended June 30, ~~2016,~~2017, that have materially affected, or are reasonably likely to materially affect, the Company's internal control over financial reporting.

PART II — OTHER INFORMATION

Item 1. Legal Proceedings

From time to time, we are subject to various claims and legal proceedings that arise in the ordinary course of business. We accrue for losses related to litigation when a potential loss is probable and the loss can be reasonably estimated in accordance with FASB requirements. During the reported period, we were not a party to any material legal proceedings, thus no loss was probable and no amount was accrued at June 30, ~~2016.~~2017.

Item 1A. Risk Factors

Item 1A, “Risk Factors,” on pages 1213 through 1920 of the ~~Company’s~~Company’s Annual Report on Form 10-K for the year ended December 31, ~~2015,~~2016, provides information on the significant risks associated with our business. There have been no subsequent material changes to these risks.

Item 2. Unregistered Sales of Equity Securities and Use of Proceeds

The table below sets forth the information with respect to purchases made by or on behalf of the Company or any “affiliated purchaser” (as the term is defined in Rule 10b-18(a)(3) under the ~~Securities~~ Exchange ~~Act of 1934)~~Act) of our common stock during the three months ended June 30, ~~2016~~2017 (in thousands except per share amounts):

ISSUER PURCHASES OF EQUITY SECURITIES

Period	Total Number of Shares Purchased (1)		Average Price Paid Per Share		Total Number of Shares Purchased as Part of Publicly Announced Programs (1)		Approximate Dollar Value of Shares that May Yet Be Purchased Under Programs(1)
Month #4 (April 1, 2017 through April 30, 2017)		—	$	—		—	$	25,000
Month #5 (May 1, 2017 through May 31, 2017)		239	$	17.30		239	$	20,869
Month #6 (June 1, 2017 through June 30, 2017)		37	$	17.04		37	$	20,230
Total		276	$	17.27		276

Period

Total
Number of
Shares
Purchased
(1)

Average
Price Paid
Per Share

Total
Number of
Shares
Purchased
as
Part of
Publicly
Announced
Programs
(1)

Approximate
Dollar
Value of
Shares that
May Yet Be
Purchased
Under
Programs(1)

Month #4 (April 1, 2016 through April 30, 2016)
— $ — — $ 10,475
Month #5 (May 1, 2016 through May 31, 2016)
— $ — — $ 10,475
Month #6 (June 1, 2016 through June 30, 2016)
129 $ 14.24 129 $ 8,631
Total
129 $ 14.24 129

(1)

On October ~~21, 2014,~~25, 2016, the Board of Directors adopted a new program, ~~effectively~~effective immediately, to repurchase up to $25.0 million of the ~~Company’s~~Company’s common stock both on the open market and in privately negotiated transactions over the next two years.

Item 3. Defaults Upon Senior Securities

None.

Item 4. Mine Safety Disclosures

None.

Item 5. Other Information

None.

Item 6. Exhibits

Exhibit Number		Description

10.20		PDF Solutions, Inc.’s ~~Third~~Fourth Amended and Restated 2011 Stock Incentive Plan, ~~(filed~~filed as Appendix A to the Company’s Proxy Statement ~~on Form DEF14A~~filed on April ~~13, 2016,~~14, 2017, and incorporated herein by ~~reference).~~reference.†

31.01		Certification of the principal executive officer pursuant to Exchange Act Rules 13a-14(a) and 15d-14(a), as Adopted Pursuant to Section 302 of the Sarbanes-Oxley Act of 2002.

31.02		Certification of the principal financial and accounting officer pursuant to Exchange Act Rules 13a-14(a) and 15d-14(a), as Adopted Pursuant to Section 302 of the Sarbanes-Oxley Act of 2002.

32.01		Certification pursuant to 18 U.S.C. Section 1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002.

32.02		Certification pursuant to 18 U.S.C. Section 1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002.

101.INS		XBRL Instance Document.

101.SCH		XBRL Taxonomy Extension Schema Document.

101.CAL		XBRL Taxonomy Extension Calculation Linkbase Document.

101.DEF		XBRL Taxonomy Extension Definition Linkbase Document.

101.LAB		XBRL Taxonomy Extension Label Linkbase Document.

101.PRE		XBRL Taxonomy Extension Presentation Linkbase Document.

		† Management contract or compensatory plan arrangement.

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the Registrant has duly caused this report to be signed on its behalf by the undersigned thereunto duly authorized.

	PDF SOLUTIONS, INC.


Date: August 4, ~~2016~~2017	By:	/s/ JOHN K. KIBARIAN
		John K. Kibarian
		President and Chief Executive Officer
		(principal executive officer)

Date: August 4, ~~2016~~2017	By:	/s/ GREGORY C. WALKER
		Gregory C. Walker
		Vice President, Finance and Chief Financial Officer
		(principal financial and accounting officer)

INDEX TO EXHIBITS

Exhibit Number		Description

10.20		PDF Solutions, Inc.’s ~~Third~~Fourth Amended and Restated 2011 Stock Incentive Plan, ~~(filed~~filed as Appendix A to the Company’s Proxy Statement ~~on Form DEF14A~~filed on April ~~13, 2016,~~14, 2017, and incorporated herein by ~~reference).~~reference.†

31.01		Certification of the principal executive officer pursuant to Exchange Act Rules 13a-14(a) and 15d-14(a), as Adopted Pursuant to Section 302 of the Sarbanes-Oxley Act of 2002.

31.02		Certification of the principal financial and accounting officer pursuant to Exchange Act Rules 13a-14(a) and 15d-14(a), as Adopted Pursuant to Section 302 of the Sarbanes-Oxley Act of 2002.

32.01		Certification pursuant to 18 U.S.C. Section 1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002.

32.02		Certification pursuant to 18 U.S.C. Section 1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002.

101.INS		XBRL Instance Document.

101.SCH		XBRL Taxonomy Extension Schema Document.

101.CAL		XBRL Taxonomy Extension Calculation Linkbase Document.

101.DEF		XBRL Taxonomy Extension Definition Linkbase Document.

101.LAB		XBRL Taxonomy Extension Label Linkbase Document.

101.PRE		XBRL Taxonomy Extension Presentation Linkbase Document.

		† Management contract or compensatory plan arrangement.

	Three Months Ended June 30,					Six Months Ended June 30,
	2016			2015		2016			2015

Revenues:
Design-to-silicon-yield solutions	$	20,574		$	14,159	$	39,152		$	32,311
Gainshare performance incentives		6,114			9,051		12,617			17,716
Total revenues		26,688			23,210		51,769			50,027

Costs of Design-to-silicon-yield solutions:
Direct costs of Design-to-silicon-yield solutions		10,558			9,888		20,668			18,692
Amortization of acquired technology		96			—		192			—
Total cost of Design-to-silicon-yield solutions		10,654			9,888		20,860			18,692
Gross profit		16,034			13,322		30,909			31,335

Operating expenses:
Research and development		7,060			4,437		13,371			8,525
Selling, general and administrative		5,094			5,216		10,218			9,672
Amortization of other acquired intangible assets		117			—		234			—
Total operating expenses		12,271			9,653		23,823			18,197

Income from operations		3,763			3,669		7,086			13,138
Interest and other income (expense), net		(51	)		52		(287	)		103
Income before income taxes		3,712			3,721		6,799			13,241
Income tax provision		1,498			1,572		2,523			5,125
Net income	$	2,214		$	2,149	$	4,276		$	8,116

Net income per share:
Basic	$	0.07		$	0.07	$	0.14		$	0.26
Diluted	$	0.07		$	0.07	$	0.13		$	0.25

Weighted average common shares:
Basic		31,276			31,522		31,222			31,429
Diluted		32,023			32,400		31,872			32,345


Net income	$	2,214		$	2,149	$	4,276		$	8,116
Other comprehensive income:
Foreign currency translation adjustments, net of tax		(186	)		146		173			(602	)
Comprehensive income	$	2,028		$	2,295	$	4,449		$	7,514

	June 30, 2016
Balance as of December 31, 2015	$	215
Adjustment		—
Balance as of June 30, 2016	$	215

	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, 2016		1,764		$	7.88
Granted (weighted average fair value of $4.46 per share)		50		$	11.87
Exercised		(63	)	$	7.20
Canceled		(7	)	$	15.01
Expired		(75	)	$	13.79
Outstanding, June 30, 2016		1,669		$	7.73		4.87	$	10,719
Vested and expected to vest, June 30, 2016		1,660		$	7.70		4.84	$	10,704
Exercisable, June 30, 2016		1,523		$	7.17		4.49	$	10,539

	Six months EndedJune 30,
	2016			2015
Expected life (in years)		1.25			1.25
Volatility		44.15	%		54.21	%
Risk-free interest rate		0.50	%		0.26	%
Expected dividend		—			—
Weighted average fair value of purchase rights granted under the Purchase Plan	$	3.56		$	6.19

	Three Months Ended June 30,						Six Months Ended June 30,
Customer	2016			2015			2016			2015
A		39	%		54	%		44	%		49	%
B		*	%		16	%		*	%		13	%
C		*	%		*	%		12	%		17	%
D		13	%		*	%		*	%		*	%

Period Ending June 30,	Amount
2016 (remaining six months)	$	1,028
2017		1,733
2018		1,087
2019		264
2020		195
2021 and thereafter		61
Total future minimum lease payments	$	4,368

Period	Total Number of Shares Purchased (1)		Average Price Paid Per Share		Total Number of Shares Purchased as Part of Publicly Announced Programs (1)		Approximate Dollar Value of Shares that May Yet Be Purchased Under Programs(1)
Month #4 (April 1, 2016 through April 30, 2016)		—	$	—		—	$	10,475
Month #5 (May 1, 2016 through May 31, 2016)		—	$	—		—	$	10,475
Month #6 (June 1, 2016 through June 30, 2016)		129	$	14.24		129	$	8,631
Total		129	$	14.24		129