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PDF SOLUTIONS INC - Quarter Report: 2013 March (Form 10-Q)

pdfs_10q-033113.htm


UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
 

FORM 10-Q

 
R
QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934
 
     
 
For the Quarterly Period ended March 31, 2013
 
     
 
or
 
     
£
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)
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 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 R 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 R 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
R Accelerated filer
£ Non-accelerated  filer
£ Smaller reporting company
   
(Do not check if a smaller reporting company)
 

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

The number of shares outstanding of the Registrant’s Common Stock as of May 1, 2013 was 29,518,711.
 


 
1

 
 
TABLE OF CONTENTS
 
 
Page
PART I  FINANCIAL INFORMATION
 
Item 1. Financial Statements (Unaudited)
 
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 Discussion and Analysis of Financial Condition and Results of Operations
14
Item 3. Quantitative and Qualitative Disclosures About Market Risk
22
Item 4. Controls and Procedures
22
PART II  OTHER INFORMATION
 
Item 1. Legal Proceedings
23
Item 1A. Risk Factors
23
Item 2. Unregistered Sales of Equity Securities and Use of Proceeds
23
Item 3. Defaults Upon Senior Securities
24
Item 4. Mine Safety Disclosure
24
Item 5. Other Information
24
Item 6. Exhibits
25
SIGNATURES
26
INDEX TO EXHIBITS
27
 
 
2

 
 
PART I — FINANCIAL INFORMATION
 
Item 1. Financial Statements

PDF SOLUTIONS, INC.
CONDENSED CONSOLIDATED BALANCE SHEETS
(unaudited)
(in thousands, except par value)
 
   
March 31,
2013
   
December 31,
2012
 
ASSETS
           
Current assets:
           
Cash and cash equivalents
 
$
63,183
   
$
61,637
 
Accounts receivable, net of allowance of $351 in both 2013 and 2012
   
32,383
     
33,959
 
Deferred tax assets - current portion
   
7,742
     
3,589
 
Prepaid expenses and other current assets
   
4,692
     
3,413
 
Total current assets
   
108,000
     
102,598
 
Property and equipment, net
   
4,953
     
3,898
 
Deferred tax assets - non-current portion
   
11,343
     
16,471
 
Other non-current assets
   
2,171
     
1,293
 
Total assets
 
$
126,467
   
$
124,260
 
LIABILITIES AND STOCKHOLDERS’ EQUITY
               
Current liabilities:
               
Accounts payable
 
$
1,347
   
$
2,054
 
Accrued compensation and related benefits
   
5,886
     
10,723
 
Accrued and other current liabilities
   
2,018
     
2,882
 
Deferred revenues
   
3,763
     
3,232
 
Billings in excess of recognized revenues
   
648
     
807
 
Total current liabilities
   
13,662
     
19,698
 
Non-current liabilities
   
3,267
     
3,502
 
Total liabilities
   
16,929
     
23,200
 
Commitments and contingencies (Note 10)
               
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 34,290 and 34,027, respectively; shares outstanding 29,503 and 29,226, respectively
   
4
     
4
 
Additional paid-in-capital
   
224,129
     
220,361
 
Treasury stock at cost, 4,787 and 4,801 shares, respectively
   
(27,630
)
   
(27,778
)
Accumulated deficit
   
(86,847
)
   
(91,578
)
Accumulated other comprehensive income (loss)
   
(118
)
   
51
 
Total stockholders’ equity
   
109,538
     
101,060
 
Total liabilities and stockholders’ equity
 
$
126,467
   
$
124,260
 
 
See accompanying Notes to Condensed Consolidated Financial Statements (unaudited).
 
 
3

 
 
PDF SOLUTIONS, INC.
CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE INCOME
(unaudited)
(in thousands, except per share amounts)

   
Three Months Ended March 31,
 
   
2013
   
2012
 
Revenues:
           
Design-to-silicon-yield solutions
 
$
14,848
   
$
13,386
 
Gainshare performance incentives
   
9,262
     
7,257
 
Total revenues
   
24,110
     
20,643
 
                 
Cost of design-to-silicon-yield solutions:
               
Direct costs of design-to-silicon-yield solutions
   
9,657
     
8,572
 
Amortization of acquired technology
   
     
156
 
Total cost of design-to silicon-yield solutions
   
9,657
     
8,728
 
Gross profit
   
14,453
     
11,915
 
                 
Operating expenses:
               
Research and development
   
3,364
     
3,157
 
Selling, general and administrative
   
4,794
     
4,905
 
Amortization of other acquired intangible assets
   
18
     
51
 
Restructuring credits
   
(52
)
   
(8
)
Total operating expenses
   
8,124
     
8,105
 
                 
Income from operations
   
6,329
     
3,810
 
Interest and other income (expense), net
   
250
     
(142
)
Income before income taxes
   
6,579
     
3,668
 
Income tax provision
   
1,848
     
169
 
Net income
 
$
4,731
   
$
3,499
 
                 
Net income per share:
               
Basic
 
$
0.16
   
$
0.12
 
Diluted
 
$
0.15
   
$
0.12
 
Weighted average common shares
               
Basic
   
29,353
     
28,384
 
Diluted
   
30,815
     
29,046
 
Net income
 
$
4,731
   
$
3,499
 
Other comprehensive income:
               
Foreign currency translation adjustments, net of tax
   
(169
)
   
191
 
Comprehensive income
 
$
4,562
   
$
3,690
 
 
See accompanying Notes to Condensed Consolidated Financial Statements (unaudited).
 
 
4

 
 
PDF SOLUTIONS, INC.
CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS
(unaudited)
(in thousands)

   
Three Months Ended
March 31,
 
   
2013
   
2012
 
Operating activities:
           
Net income
 
$
4,731
   
$
3,499
 
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
               
Depreciation and amortization
   
276
     
297
 
Stock-based compensation expense
   
1,309
     
905
 
Deferred taxes
   
981
     
(23
)
Purchases of treasury stock in connection with tax withholdings on restricted stock grants
   
(8
)
   
(19
)
Provisions for doubtful accounts
   
     
37
 
Loss on disposal of property and equipment
   
46
     
 
Tax benefit related to stock-based compensation expense
   
888
     
 
Excess tax benefit from stock-based compensation
   
(747
)
   
 
Changes in operating assets and liabilities:
               
Accounts receivable
   
1,844
     
(6,786
)
Prepaid expenses and other assets
   
(2,528
)
   
(80
)
Accounts payable
   
(1,064
)
   
237
 
Accrued compensation and related benefits
   
(4,832
)
   
810
 
Accrued and other liabilities
   
(1,055
)
   
77
 
Deferred revenues
   
668
     
379
 
Billings in excess of recognized revenues
   
(159
)
   
(746
)
Net cash provided by (used in) operating activities
   
350
     
(1,413
)
Investing activities:
               
Purchases of property and equipment
   
(1,211
)
   
(127
)
Net cash used in investing activities
   
(1,211
)
   
(127
)
Financing activities:
               
Proceeds from exercise of stock options
   
1,201
     
584
 
Proceeds from employee stock purchase plan
   
546
     
468
 
Excess tax benefit from stock-based compensation
   
747
     
 
Net cash provided by financing activities
   
2,494
     
1,052
 
Effect of exchange rate changes on cash and cash equivalents
   
(87
)
   
(22
)
Net change in cash and cash equivalents
   
1,546
     
(510
)
Cash and cash equivalents, beginning of period
   
61,637
     
46,041
 
Cash and cash equivalents, end of period
 
$
63,183
   
$
45,531
 
Supplemental disclosure of cash flow information:
               
Cash paid during the period for:
               
Income Taxes
 
$
779
   
$
440
 
 
See accompanying Notes to Condensed Consolidated Financial Statements (unaudited).
 
 
5

 
 
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”) 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 Annual Report on Form 10-K for the year ended December 31, 2012.

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

The condensed consolidated balance sheet at December 31, 2012  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 stock-based compensation expense, allowances for doubtful accounts receivable, estimates for useful lives associated with long-lived assets, restructuring charges, fair value of financial instruments and income taxes and tax valuation allowances. 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 — Revenue that is derived from Design-to-silicon-yield solutions comes from services and software licenses. The Company recognizes revenue of Design-to-silicon-yield solutions as follows:
 
The Company generates a significant portion of its Design-to-silicon-yield solutions revenue from fixed-price solution implementation service contracts delivered over a specific period of time. These contracts require reliable estimation of costs to perform obligations and the overall scope of each engagement. Revenue under project–based contracts for solution implementation services is recognized as services are performed using the cost-to-cost percentage of completion method of contract accounting. Revenue under term-based contracts for solution implementation services are recognized under the proportional performance method. Losses on 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. On occasion, the Company licenses its software products as a component of its fixed-price service contracts. In such instances, the software products are licensed to customers over a specified term of the agreement with support and maintenance to be provided at each customer's option 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. Fees allocated to solution implementation services are recognized using the cost-to-cost percentage of completion method of contract accounting. Fees allocated to software and related support and maintenance are recognized under software revenue recognition guidance.
 
 
6

 
 
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) 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 VSOE and such services are recorded as services revenue. VSOE for maintenance is generally established based upon negotiated renewal rates while VSOE for consulting, installation, and training services is established based upon the Company’s customary pricing for such services when sold separately. 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 cost-to-cost percentage of completion method of contract accounting, and such revenue is recorded as services revenue.

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 variable fee, usually after the fixed fee period has ended. Revenue derived from Gainshare performance incentives represents profit sharing and performance incentives earned based 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 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

In December 2011, the Financial Accounting Standards Board (“FASB”) amended its guidance related to the disclosures about offsetting assets and liabilities. The standard requires the Company to disclose information about offsetting and related arrangements to enable users of its financial statements to understand the effect of those arrangements on its financial position. The guidance is effective for annual reporting periods beginning on or after January 1, 2013, and interim periods within those annual periods. The disclosures are to be applied retrospectively for all comparative periods presented. The adoption of this guidance did not have a material impact on the Company’s consolidated financial statements as it is disclosure-only in nature.
 
In June 2011, the FASB amended its guidance related to the presentation of comprehensive income to increase comparability between U.S. GAAP and International Financial Reporting Standards (“IFRS”). This amended guidance eliminates the current option to report other comprehensive income and its components in the statement of changes in equity and instead requires presenting in one continuous statement or two separate but consecutive statements. Additionally, the amendment requires entities to present reclassification adjustments to show the effect of reclassifications on both the components of other comprehensive income and the components of net income in interim and annual financial statements. The amendments are effective for fiscal years, and interim periods within those years, beginning after December 15, 2011 with early adoption permitted. The guidance is effective for the Company’s fiscal year beginning January 1, 2012. In December 2011, the FASB issued an amendment to defer the presentation on the face of the financial statements the effects of reclassifications out of accumulated other comprehensive income on the components of net income and other comprehensive income for annual and interim financial statements. In February 2013, the FASB issued amendments to disclosure requirements for presentation of comprehensive income. The standard requires presentation (either in a single note or parenthetically on the face of the financial statements) of the effect of significant amounts reclassified from each component of accumulated other comprehensive income based on its source and the income statement line items affected by the reclassification. If a component is not required to be reclassified to net income in its entirety, a cross reference to the related footnote for additional information will be required. The amendments are effective prospectively for reporting periods beginning after December 15, 2012. The adoption of this guidance did not have a material impact on the Company’s consolidated financial statement.
 
 
3. BALANCE SHEET COMPONENTS

Accounts receivable include amounts that are unbilled at the end of the period. Unbilled accounts receivable are determined on an individual contract basis and were $6.2 million and $7.7 million as of March 31, 2013 and December 31, 2012, respectively.

 
7

 
 
Property and equipment consists of (in thousands): 
 
   
March 31,
2013
   
December 31,
2012
 
Property and equipment, net:
               
Computer equipment
 
$
10,368
   
$
10,319
 
Software
   
3,527
     
3,552
 
Furniture, fixtures and equipment
   
979
     
971
 
Leasehold improvements
   
1,030
     
1,021
 
Test equipment
   
3,050
     
2,005
 
Construction-in-progress
   
980
     
864
 
     
19,934
     
18,732
 
Less: accumulated depreciation
   
(14,981
)
   
(14,834
)
Total
 
$
4,953
   
$
3,898
 

Depreciation and amortization expense was $0.3 million and $0.1 million for the three months ended March 31, 2013 2012, respectively.

Intangible assets balance was $86,000 and $104,000 as of March 31, 2013 and December 31, 2012, respectively. The balance was included in other non-current assets in the accompanying condensed consolidated balance sheets. For the three months ended March 31, 2013 and 2012, intangible asset amortization expense was $18,000 and $207,000, respectively. The Company expects the amortization of its existing intangible assets to be $56,000 for the remaining nine months in 2013 and $30,000 in 2014.
 
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 months ended March 31, 2013 and 2012, there were no indicators of impairment related to the Company’s intangible assets.
 
 
4. STOCKHOLDERS’ EQUITY
 
Stock-based compensation is estimated at the grant date based on the award’s fair value and is recognized on a straight-line basis over the vesting periods of the applicable stock purchase rights and stock options, generally four years. Stock-based compensation expenses before taxes related to the Company’s stock plans and employee stock purchase plan were allocated as follows (in thousands):

   
Three Months
Ended March 31,
 
   
2013
   
2012
 
Cost of design-to-silicon-yield solutions
 
$
534
   
$
319
 
Research and development
   
322
     
187
 
Selling, general and administrative
   
453
     
399
 
Stock-based compensation expenses
 
$
1,309
   
$
905
 

The Company estimated the fair value of share-based awards granted 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:
 
   
Stock Plans
Three Months Ended March 31,
   
Employee Stock Purchase Plan
Three Months Ended March 31,
 
   
2013
   
2012
   
2013
   
2012
 
Expected life (in years)
   
4.78
     
4.58
     
1.25
     
1.25
 
Volatility
   
56.4
%
   
60.6
%
   
46.1
%
   
47.3
%
Risk-free interest rate
   
0.80
%
   
0.78
%
   
0.19
%
   
0.35
%
Expected dividend
   
     
     
     
 
Weighted average fair value per share of options granted during the period
 
$
7.54
   
$
3.23
     
     
 
Weighted average fair value per share of employee stock purchase plan rights granted during the period
   
     
   
$
5.28
   
$
2.03
 

 
8

 
 
On March 31, 2013, the Company has in effect the following stock-based compensation plans:

Stock Plans — At the annual meeting of stockholders on November 16, 2011, the Company’s stockholders approved the 2011 Stock Incentive Plan (the “2011 Plan”). Under the 2011 Plan, the Company may award stock options, stock appreciation rights, stock grants or stock units covering shares of the Company's common stock to employees, directors, non-employee directors and contractors. The aggregate number of shares reserved for awards under this plan is 3,200,000 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.
  
On April 4, 2013, the Company’s Board of Directors amended the 2011 Plan, subject to the approval of the stockholders, to increase the number of shares reserved for awards under it by an additional 1,600,000 shares for a total of 4,800,000 shares.

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 2001 and the IDS Plans expired in 2011.  Stock options granted under the 2001 and IDS Plans generally expire ten years from the date of grant and become vested and exercisable over a four-year period. Although 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 of March 31, 2013, 3.5 million shares of common stock were reserved to cover stock-based awards under the 2011 Plan, of which 1.8 million shares were available for future grant. The number of shares reserved and available under the 2011 Plan includes 0.3 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 March 31, 2013.  As of March 31, 2013, there were no outstanding awards that had been granted outside of the 2011, 2001 or the IDS Plans (collectively, the "Stock Plans").
 
Stock option activity under the Company’s Stock Plans during the three months ended March 31, 2013 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, 2013
   
3,810
   
$
6.91
             
Granted
   
48
    $
15.95
             
Exercised
   
(170
)
  $
6.90
             
Canceled
   
(38
)
  $
6.59
             
Expired
   
(14
)
  $
5.39
             
Outstanding, March 31, 2013
   
3,636
    $
7.03
     
7.21
   
$
32,687
 
Vested and expected to vest, March 31, 2013
   
3,418
    $
6.96
     
7.11
   
$
30,980
 
Exercisable, March 31, 2013
   
1,913
    $
6.58
     
6.02
   
$
18,065
 
 
The aggregate intrinsic value in the table above represents the total intrinsic value based on the Company’s closing stock price of $16.02 per share as of March 31, 2013, which would have been received by the option holders had all “in-the-money” option holders exercised their options as of that date. The total intrinsic value of options exercised during the three months ended March 31, 2013 was $1.5 million.

As of March 31, 2013, there was $5.6  million of total unrecognized compensation cost related to unvested stock options. That cost is expected to be recognized over a weighted average period of 2.48 years. The total fair value of shares vested during the three months ended March 31, 2013 was $0.8 million.

 
9

 
 
Nonvested restricted stock units activity during the three  months ended March 31, 2013 was as follows:
 
   
Shares
(in thousands)
   
Weighted
Average
Grant Date
Fair Value Per
Share
 
Nonvested, January 1, 2013
   
450
   
$
7.97
 
Granted
   
    $
 
Vested
   
(3
)
  $
5.16
 
Forfeited
   
(9
)
  $
7.27
 
Nonvested, March 31, 2013
   
438
    $
7.82
 
 
As of March 31, 2013, there was $2.5 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 2.7 years.
 
Employee Stock Purchase Plan — In July 2001, the Company adopted a ten-year Employee Stock Purchase Plan (“Purchase Plan”) under which eligible employees can contribute up to 10% of their compensation, as defined in the Purchase Plan, towards the purchase of shares of PDF common stock at a price of 85% of the lower of the fair market value at the beginning of the offering period or the end of the purchase period. The Purchase Plan consists of twenty-four-month offering periods with four six-month purchase periods in each offering period. Under the Purchase Plan, on January 1 of each year, starting with 2002, the number of shares reserved for issuance will automatically increase by the lesser of (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.  During the three months ended March 31, 2013 and 2012, a total of 104,000 and 97,000 shares, respectively, were issued at a weighted-average purchase price of $5.24 and $4.81 per share, respectively, under the Purchase Plan. For the three months ended March 31, 2013 and 2012, the Purchase Plan compensation expense was $0.2 million and $0.1 million, respectively. As of March 31, 2013, there was $0.8 million of unrecognized compensation cost related to the Purchase Plan. That cost is expected to be recognized over a weighted average period of 1.7 years. As of March 31, 2013, 1.3 million shares were available for future issuance under the Purchase Plan.
 
Stock Repurchase Program — On October 29, 2007, the Board of Directors adopted a program to repurchase up to $10.0 million of the Company’s common stock on the open market. The initial program was for three years, but on October 19, 2010, the Board of Directors authorized an extension of, and an increase in, the program and the aggregate amount available to repurchase between October 19, 2010 and October 29, 2012 was reset to $10.0 million of the Company’s common stock, meaning a total of $19.3 million was available. The program expired on October 29, 2012, as of which date, 3.8 million shares had been repurchased at the average price of $4.53 per share and a total purchase price of $17.0 million. On November 8, 2012, the Board of Directors adopted a new program to repurchase up to $20.0 million of the Company’s common stock on the open market over the next two years. As of  March 31, 2013, 36,100 shares had been repurchased at the average price of $13.23 per share under this new program, a total purchase of $0.5 million, and $19.5 million remained available for future repurchases.


5. RESTRUCTURING

The Company implemented restructuring plans during fiscal years 2012 and 2008, and recorded total restructuring credits of $52,000 and $8,000 for the three months ended on March 31, 2013 and 2012, respectively. As of March 31, 2013, the remaining restructuring accrual was $0.4 million and the amount consists of $0.2 million of employee severance charges, which the Company expects to pay out by the end of 2013 and $0.2 million of facility exit costs which the Company expects to pay in accordance with the lease payment schedule through the end of the third quarter of 2013. This remaining accrual balance of $0.4 million was included in accrued and other current liabilities in the accompanying consolidated balance sheets.

October 2012 Plan

On October 24, 2012, the Company announced a restructuring plan as part of the Company’s continuing efforts to simplify the organization, leverage cross-training and learning, and reduce annual operations expenses. Under this plan, the Company has recorded restructuring charges of $1.8 million, which primarily consisted of employee severance costs of $1.7 million. The following table summarizes the activities of these restructuring liabilities (in thousands) for the periods covered below:

   
Three Months
Ended
March 31, 2013
 
Beginning balance
 
$
896
 
Restructuring charges (credits)
   
50
 
Cash payments
   
(736
)
Ending balance
 
$
210
 
 
 
10

 
 
October 2008 Plan

On October 28, 2008, the Company announced a restructuring plan to better allocate its resources to improve its operational results in light of the market conditions. Under this plan, the Company has recorded restructuring charges of $7.4 million, primarily consisting of employee severance costs of $4.7 million and facility exit costs of $2.7 million. The facility exit cost consists primarily of the cost of future obligations related to these facilities. Discounted liabilities for future lease costs and the fair value of the related subleases of closed locations that are recorded is subject to adjustments as liabilities are settled. In assessing the discounted liabilities for future costs of obligations related to the locations, the Company made assumptions regarding the amounts of future subleases. If these assumptions or their related estimates change in the future, the Company may be required to record additional exit costs or reduce exit costs previously recorded. Exit costs recorded for each period presented include the effect of such changes in estimates. The following table summarizes the activities of these restructuring liabilities (in thousands) for the periods covered below:

   
Three Months
Ended March 31,
 
   
2013
   
2012
 
Beginning balance
 
$
448
   
$
728
 
Restructuring charges (credits)
   
(102
)
   
(8
)
Adjustments
   
     
4
 
Cash payments
   
(122
)
   
(102
)
Ending balance
 
$
224
   
$
622
 
 
6. INCOME TAXES

Income tax provision increased $1.7 million for the three months ended March 31, 2013 to $1.9 million as compared to an income tax provision of $0.2 million for the three month ended March 31, 2012.  The Company’s effective tax rate was 28.09% and 4.61% for the three months ended March 31, 2013 and March 31, 2012, respectively.  The income tax provision for the three months ended March 31, 2013 was less than the provision at the statutory rate primarily due to changes in unrecognized tax benefits and the benefit of the research and development tax credit explained below. The income tax provision for the three months ended March 31, 2012 was significantly less than the provision at the statutory rate primarily due to the reduction of the valuation allowance related to the utilization of U.S. tax credits, offset by foreign withholding taxes, statutory taxes, and changes in unrecognized tax benefits.

On January 2, 2013, the President signed into law the American Taxpayer Relief Act which reinstated the U.S. Federal Research and Development tax credit retroactive to January 1, 2012 and extended the tax credit through December 31, 2013.  As a result of the new legislation, the Company recognized a benefit in the three months ended March 31, 2013 related to 12 months of fiscal 2012 as well as a benefit to the annual effective tax rate for the full year research tax credit for fiscal 2013.

The Company’s total amount of unrecognized tax benefits, excluding interest and penalties, as of March 31, 2013 was $9.5 million, of which $5.8 million, if recognized, would affect the Company’s effective tax rate. The Company’s total amount of unrecognized tax benefits, excluding interest and penalties, as of December 31, 2012 was $9.6 million, of which $6.0 million, if recognized, would affect the Company's effective tax rate. As of March 31, 2013, the Company has recognized unrecognized tax benefits of  $2.9 million, including interest and penalties, as long-term taxes payable  in its condensed consolidated balance sheet. The remaining $7.0 million has been recorded net of our deferred tax assets, of which $3.6 million is subject to a full valuation allowance.

As of March 31, 2013, the Company believes that most of its deferred tax assets are “more likely than not” to be realized with the exception of  California R&D tax credits that have not met the “more likely than not” realization threshold criteria because on an annual basis and pursuant to current law, the Company generates more California credits than California tax. As a result, at March 31, 2013, the excess credits continue to be subject to a full valuation allowance. In the event the Company concludes at a future financial reporting period that there has been a change in its ability to recover the deferred tax assets, and it is at such time no longer “more likely than not” that the Company will recover the tax credits before applicable expiration dates, the Company’s tax provision will increase in the period in which the Company makes such determination.

The Company conducts business globally and, as a result, files numerous consolidated and separate income tax returns in the U.S. federal, various state and foreign jurisdictions. Because the Company used some of the tax attributes carried forward from previous years to tax years that are still open, statutes of limitation remain open for all tax years to the extent of the attributes carried forward into tax year 2002 for federal and California tax purposes. The Company is not subject to income tax examinations in any other of its major foreign subsidiaries’ jurisdictions.

 
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7. NET INCOME (LOSS) PER SHARE

Basic net income (loss) per share is computed by dividing net income (loss) by weighted average number of common shares outstanding for the period (excluding outstanding stock options and shares subject to repurchase). Diluted net income (loss) 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 (loss) per share (in thousands except per share amount):
 
   
Three Months
Ended March 31,
 
   
2013
   
2012
 
Numerator:
               
Net income (loss)
 
$
4,731
   
$
3,499
 
Denominator:
               
Basic weighted-average shares outstanding
   
29,353
     
28,384
 
Effect of dilutive options and restricted stock
   
1,462
     
662
 
Diluted weighted average shares outstanding
   
30,815
     
29,046
 
                 
Net income (loss) per share - Basic
 
$
0.16
   
$
0.12
 
Net income (loss) per share - Diluted
 
$
0.15
   
$
0.12
 
 
The following table sets forth potential shares of common stock that are not included in the diluted net income ( loss) per share calculation above because to do so would be anti-dilutive for the periods indicated (in thousands):
 
   
Three Months
Ended March 31,
 
   
2013
   
2012
 
Outstanding options
   
132
     
1,906
 
Nonvested restricted stock units
   
     
42
 
Total
   
132
     
1,948
 
 

8. CUSTOMER AND GEOGRAPHIC INFORMATION

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

The Company’s chief operating decision maker, the chief executive officer, reviews discrete financial information presented on a consolidated basis for purposes of regularly making operating decisions and assessing financial performance. Accordingly the Company considers itself to be in one operating segment, specifically the licensing and implementation of yield improvement solutions for companies designing and/or manufacturing integrated circuits.
 
The Company had revenues from individual customers in excess of 10% of total revenues as follows:
 
   
Three Months
Ended March 31,
 
Customer
 
2013
   
2012
 
A
   
33
%
   
44
%
B
   
25
%
   
12
%
C
   
16
%
   
20
%

 
12

 
 
The Company had gross accounts receivable from the following individual customers in excess of 10% of gross accounts receivable as follows:
 
Customer
 
March 31, 2013
   
December 31, 2012
 
A
   
33
%
   
42
%
B
   
26
%
   
11
%
C
   
12
%
   
18
%

Revenues from customers by geographic area based on the location of the customers’ work sites are as follows (in thousands):
 
   
Three Months
Ended March 31,
 
   
2013
   
2012
 
United States
 
$
9,866
   
$
6,872
 
Asia
   
8,717
     
5,217
 
Europe
   
5,527
     
8,554
 
Total
 
$
24,110
   
$
20,643
 
 
Long-lived assets, net by geographic area are as follows (in thousands):
 
   
March 31, 2013
   
December 31,
2012
 
United States
 
$
4,543
   
$
3,527
 
Asia
   
315
     
295
 
Europe
   
95
     
76
 
Total long-lived assets, net
 
$
4,953
   
$
3,898
 

 
9. 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 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 assets measured at fair value on a recurring basis as of March 31, 2013 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
 
$
26,346
   
$
26,346
   
$
   
$
 
 
 
13

 

The following table represents the Company’s assets measured at fair value on a recurring basis as of December 31, 2012 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
 
$
26,341
   
$
26,341
   
$
   
$
 
 
 
10. 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 2018. Rent expense was $0.5 million and $0.7 million for the three months ended March 31, 2013 and 2012, respectively.

Future minimum lease payments under noncancelable operating leases at March 31, 2013 are as follows (in thousands):
 
Year Ending December 31,
 
Amount
 
2013 (remaining nine months)
 
$
1,015
 
2014
   
1,691
 
2015
   
1,561
 
2016
   
1,563
 
2017
   
1,289
 
Thereafter
   
695
 
Total future minimum lease payments
 
$
7,814
 
 
The operating lease obligations have been reduced by future minimum sublease rental income of $0.2 million in the remaining nine months of 2013.
 
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. With respect to the matter below, the Company determined a potential loss was not probable at March 31, 2013 and, accordingly, no amount was accrued at such time.

Philip Steven Melman filed a complaint against the Company and the Company's Chief Executive Officer on December 7, 2009 in the Superior Court for Santa Clara County. In the complaint, Mr. Melman alleged wrongful discharge based on discrimination, fraud, breach of contract and similar theories, in connection with the termination of Mr. Melman's employment with the Company. The complaint sought compensatory and punitive damages, any other available remedies, as well as attorney's fees and costs. Summary judgment in the favor of both the Company and Dr. Kibarian was entered by the court on October 27, 2011 and November 15, 2011, respectively. Mr. Melman appealed both orders in the Sixth District Court of Appeal in Santa Clara County. On March 22, 2013, the Court released its opinion affirming in full the grant of summary judgment in favor of the Company and Dr. Kibarian, which decision became final on April 22, 2013.

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

Forward-Looking Statements

 
14

 
 
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. 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 at the end of Item 1A in our Annual Report on Form 10-K for the year ended December 31, 2012 filed with the Securities and Exchange Commission on March 18, 2013.

Overview

We analyze our 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

We believe that the largest logic foundries will continue to increase their investment in leading edge nodes and capacity in 2013, consistent with the trend since 2010. Leading foundries are also investing in new technologies such as double-patterned lithography and 3-D transistor architecture. These trends resulted in an increase in our business, and improved results in operations in 2011, 2012 and to date in 2013.
 
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 ICs at nodes below 28 nanometers 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 that address the yield loss and escalating cost issues the semiconductor industry is facing today and will face in the future.

 
Financial Highlights

Financial highlights for the three months ended March 31, 2013 were as follows:

 
Total revenues for the three months ended March 31, 2013 were $24.1 million, an increase of $3.5 million, or 17%, compared to $20.6 million for the three months ended March 31, 2012. Design-to-silicon-yield solutions revenue for the three months ended March 31, 2013 was $14.8  million, an increase of $1.4 million, or 11%, compared to $13.4 million for the three months ended March 31, 2012. The increase in Design-to-silicon-yield solutions revenue was primarily due to an increase in fixed fee integrated solutions, the result of more billable hours to revenue-generating projects in the period due to increased business activity. Gainshare performance incentives revenue for the three months ended March 31, 2013 was $9.3 million, an increase of $2.0 million, or 28%, compared to $7.3 million for the three months ended March 31, 2012. The increase in revenue from Gainshare performance incentives was primarily the result of a higher number of projects reaching performance measures for achieving gainshare and higher wafer volumes at customers’ manufacturing facilities.
 
 
15

 
 
 
Net income for the three months ended March 31, 2013 was $4.7 million, compared to $3.5 million for the three months ended March 31, 2012. The increase in net income was primarily attributable to an increase in gross margin of $2.5 million mainly due to an increase in revenues of $3.5 million and a more favorable product mix, an increase in interest and other income (expense) of $0.4 million, offset by an increase in income tax provision of $1.7 million.

 
Net income per basic and diluted share was $0.16 and $0.15, respectively, for the three months ended March 31, 2013 compared to net income per basic and diluted share of $0.12 for the three months ended March 31, 2012, an increase of  $0.04 and $0.03 per basic and diluted share, respectively.

 
Cash, cash equivalents and investments increased $1.6 million from $61.6 million at December 31, 2012 to $63.2  million at March 31, 2013,  primarily due to an increase in cash from operating and financing activities during the period.

 
Critical Accounting Policies

There were no significant changes in our critical accounting policies. Please refer to 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, 2012. 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 from two sources: Design-to-silicon-yield solutions, which include services and software licenses, and Gainshare performance incentives.

Design-to-Silicon-Yield Solutions — Revenue that is derived from Design-to-silicon-yield solutions comes from services and software licenses. We recognize revenue for 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–based contracts for solution implementation services is recognized as services are performed using the cost-to-cost percentage of completion method of contract accounting. Revenue under certain time-based contracts for solution implementation services is recognized under the proportional performance method. Losses on 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.  On occasion, we license our software products as a component of our 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 over the license term. The amount of product and service revenue recognized in a given period is affected by our 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 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. Fees allocated to solution implementation services are recognized using the cost-to-cost percentage of completion method of contract accounting. Fees allocated to software and related support and maintenance are recognized under software revenue recognition guidance.
 
 
16

 
 
We also license our software products separately from our solution implementation services. 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) 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. VSOE for maintenance is generally established based upon negotiated renewal rates while VSOE for consulting, installation, and training services is established based upon our customary pricing for such services when sold separately. Revenues for software licenses with extended payment terms are not recognized in excess of amounts due. For software license arrangements that require significant modification or customization of the underlying software, the software license revenues are recognized as services are performed using the cost-to-cost percentage of completion method of contract accounting, and such revenues are recorded as services revenue.
 
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 component where the customer may pay a variable fee, usually after the fixed fee period has ended. Revenues derived from Gainshare performance incentives represent profit sharing and performance incentives earned based 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 no cost to us. Due to the uncertainties surrounding attainment of such operational levels, we recognize Gainshare performance incentives revenues (to the extent of completion of the related solution implementation services) upon receipt of performance reports or other related information from our customers 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 fair value and is recognized on a straight-line basis over the vesting periods of the applicable stock purchase rights and stock options, 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 in the condensed consolidated statements of operations. As of March 31, 2013, we believed that most of our deferred tax assets were “more likely than not” to be realized with the exception of  California R&D tax credits that have not met the “more likely than not” realization threshold criteria because on an annual basis and pursuant to current law, we generate more California credits than California tax. As a result, at March 31, 2013, the excess credits continue to be subject to a full valuation allowance. See Note 6 to the condensed consolidated financial statements for further disclosures regarding our income taxes. In the event we conclude at a future financial reporting period that there has been a change in our ability to recover our deferred tax assets, and it is at such time no longer more likely than not that we will recover the tax credits before applicable expiration dates, our tax provision will increase in the period in which we make such determination.

 
17

 
 
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.

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
March 31,
 
   
2013
   
2012
 
Revenues:
           
Design-to-silicon-yield solutions
   
62
%
   
65
%
Gainshare performance incentives
   
38
     
35
 
Total revenues
   
100
%
   
100
%
Cost of design-to-silicon-yield solutions:
               
Direct costs of design-to-silicon-yield solutions
   
40
     
41
 
Amortization of acquired technology
   
     
1
 
Total cost of design-to-silicon-yield solutions
   
40
     
42
 
Gross margin
   
60
     
58
 
Operating expenses:
               
Research and development
   
14
     
15
 
Selling, general and administrative
   
20
     
24
 
Amortization of other acquired intangible assets
   
     
 
Restructuring charges
   
     
 
Total operating expenses
   
34
     
39
 
Income from operations
   
26
     
19
 
Interest and other income (expense), net
   
1
     
(1
)
Income before taxes
   
27
     
18
 
Income tax provision
   
8
     
1
 
Net income
   
19
%
   
17
%
 
Comparison of the Three Months Ended March 31, 2013 and 2012

   
Three Months Ended March 31,
   
$
   
%
 
Revenues
 
2013
   
2012
   
Change
   
Change
 
(in thousands, except for percentages)
                               
Design-to-silicon-yield solutions
 
$
14,848
   
$
13,386
   
$
1,462
     
11
%
Gainshare performance incentives
   
9,262
     
7,257
     
2,005
     
28
%
Total
 
$
24,110
   
$
20,643
   
$
3,467
     
17
%

 
18

 
 
Design-to-Silicon-Yield Solutions. Design-to-silicon-yield solutions revenue is derived from services (including solution implementations, software support and maintenance, consulting, and training) and software licenses, provided during our customer yield improvement engagements as well as during solution product sales.  Design-to-silicon-yield solutions revenue increased $1.5 million for the three months ended March 31, 2013 compared to the three months ended March 31, 2012, primarily due to an increase in fixed fee integrated solutions, the result of more billable hours to revenue-generating projects in the period due to increased business activity. Our Design-to-silicon-yield solutions revenue may fluctuate in the future and are dependent on a number of factors, including the semiconductor industry’s continued acceptance of our solutions, the timing of purchases by existing 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 businesses or, in the case of a term-based 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 based upon our customers reaching certain defined operational levels. Revenue derived from gainshare performance incentives increased $2.0 million for the three months ended March 31, 2013 compared to the three months ended March 31, 2012.  The increase was primarily the result of a higher number of projects reaching performance measures for achieving gainshare combined with higher wafer volumes at customers’ manufacturing facilities. 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, 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 March 31,
   
$
   
%
 
Cost of Design-to-Silicon-Yield Solutions
 
2013
   
2012
   
Change
   
Change
 
(in thousands, except for percentages)
                       
Direct costs of design-to-silicon-yield solutions
 
$
9,657
   
$
8,572
   
$
1,085
     
13
%
Amortization of acquired technology
   
     
156
     
(156
   
(100
)%
Total
 
$
9,657
   
$
8,728
   
$
929
     
11
%

Costs of Design-to-Silicon-Yield Solutions. Costs of Design-to-silicon-yield solutions consist of costs incurred to provide and support our services, costs recognized in connection with licensing our software, and amortization of acquired technology.

Direct Costs of Design-to-Silicon-Yield Solutions Direct costs of Design-to-Silicon-Yield solutions consist of services costs and software licenses costs. Services 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 sold in conjunction with our software products. Direct costs of Design-to-silicon-yield solutions increased $1.1 million for the three months ended March 31, 2013 compared to the three months ended March 31, 2012. The increase was primarily due to an increase of $1.0 million in personnel expense as a result of additional headcount to support the growth in revenue-generating engagements, an increase of $0.1 million in subcontractor costs related to increased project activity, an increase of $0.1 million in depreciation expense, offset by a decrease of $0.1 million in equipment costs.

Amortization of Acquired Technology. Amortization of acquired technology consists of amortization of intangible assets acquired as a result of certain business combinations. Amortization of acquired technology expense decreased $0.2 million for the three months ended March 31, 2013 compared to the three months ended March 2012, primarily due to certain intangible assets becoming fully amortized. All acquired technology intangible assets were fully amortized as of December 31, 2012.
 
   
Three Months Ended March 31,
   
$
   
%
 
Research and Development
 
2013
   
2012
   
Change
   
Change
 
(in thousands, except for percentages)
                       
Research and development
 
$
3,364
   
$
3,157
   
$
207
     
7
%

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 $0.2 million for the three months ended March 31, 2013 compared to the three months ended March 31, 2012, primarily due to an increase of $0.3 million in personnel expense, offset by a decrease of $0.1 million in outside service expenses. 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.
 
 
19

 
 
   
Three Months Ended March 31,
   
$
   
%
 
Selling, General and Administrative
 
2013
   
2012
   
Change
   
Change
 
(in thousands, except for percentages)
                       
Selling, general and administrative
 
$
4,794
   
$
4,905
   
$
(111
   
(2
)%

Selling, General and Administrative. 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 million for the three months ended March 31, 2013 compared to the three months ended March 31, 2012, primarily due to the decrease in accounting and legal fees. 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 March 31,
   
$
   
%
 
Amortization of Other Acquired Intangible Assets
 
2013
   
2012
   
Change
   
Change
 
(in thousands, except for percentages)
                       
Amortization of other acquired intangible assets
 
$
18
   
$
51
   
$
(33
   
(65
)%

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. Amortization of other acquired intangible assets for the three months ended March 31, 2013 decreased $33,000 compared to the three months ended March 31, 2012, primarily the result of certain intangible assets becoming fully amortized. We anticipate amortization of our existing other acquired intangible assets to be $56,000 for the remaining nine months in 2013, and $30,000 in 2014.

   
Three Months Ended March 31,
   
$
   
%
 
Restructuring Charges (Credits)
 
2013
   
2012
   
Change
   
Change
 
(in thousands, except for percentages)
                       
Restructuring charges (credits)
 
$
(52
)
 
$
(8
 
$
(44
   
550
%

Restructuring Charges (credits).   Restructuring credits for the three months ended March 31, 2013 increased $44,000 compared to the three months ended March 31, 2012, primarily due to a change in estimate.
 
   
Three Months Ended March 31,
   
$
   
%
 
Interest and Other Income (Expense), Net
 
2013
   
2012
   
Change
   
Change
 
(in thousands, except for percentages)
                       
Interest and other income (expense), net
 
$
250
   
$
(142
 
$
392
     
(276
)%
 
 Interest and Other Income (expense), net.  Interest and other income (expense), net increased $0.4 million for the three months ended March 31, 2013 compared to the three months ended March 31, 2012, primarily due to gains on foreign currency exchange recorded during the three months ended March 31, 2013 compared to losses on foreign currency exchange recorded during the three months ended March 31, 2012. We anticipate interest and other income (loss) will fluctuate in future periods as a result of our projected use of cash and fluctuations of foreign exchange rates.

   
Three Months Ended March 31,
   
$
   
%
 
Income Tax Provision
 
2013
   
2012
   
Change
   
Change
 
(in thousands, except for percentages)
                       
Income tax provision
 
$
1,848
   
$
169
   
$
1,679
     
993
%

Income Tax Provision. Income tax provision increased $1.7 million for the three months ended March 31, 2013 compared to three months ended March 31, 2012, primarily due to an increase in level of income. The income tax provision for the three months ended March 31, 2013 was less than the provision at the statutory rate primarily due to changes in unrecognized tax benefits and the benefit of the research and development tax credit. The income tax provision for the three months ended March 31, 2012 was significantly less than the provision at the statutory rate primarily due to the reduction of the valuation allowance related to the  utilization of U.S tax credits, offset by foreign withholding taxes, statutory taxes, and changes in unrecognized tax benefits.
 
 
20

 
 
Liquidity and Capital Resources

Operating Activities

Cash flows provided by operating activities was $0.4 million for the three months ended March 31, 2013. This resulted from net income of $4.7 million, the addition of $2.7 million from non-cash charges, offset by the cash decrease of $7.0 million reflected in the net change of operating assets and liabilities. Non-cash charges consisted primarily of stock-based compensation of $1.3 million, deferred taxes of $1.0 million, tax benefit related to stock-based compensation plan of $0.9 million, depreciation and amortization of $0.3 million, partially offset by excess tax benefit from stock-based compensation of $0.8 million. Cash flow decreases resulting from the net change in operating assets and liabilities primarily consisted of $4.8 million decrease in accrued and other liabilities, $2.5 million increase in prepaid expenses and other assets, $1.0 million decrease in accounts payable, $1.0 million decrease in accrued and other liabilities, $0.2 million decrease in billings in excess of recognized revenue, partially offset by a $1.8 million decrease in accounts receivable and $0.7 million increase in deferred revenue. The $2.4 million combined cash flow increase resulted from the increase in accounts receivable, the increase in deferred revenue and the decrease in billings in excess of recognized revenues was primarily due to the timing of billing milestones and payments received.

Cash flows used in operating activities of $1.4 million for the three months ended March 31, 2012 consisted primarily of net income of $3.5 million and non-cash charges of $1.2 million that was offset by $6.1 million of cash flow decreases reflected in the net change of operating assets and liabilities.  Non-cash charges consisted primarily of stock-based compensation of $0.9 million and depreciation and amortization of $0.3 million.  Cash flow decreases resulting from the net change in operating assets and liabilities primarily consisted of of $6.8 million increase in accounts receivable, a $0.1 million increase in prepaid expense and other assets and a $0.7 million decrease in billings in excess of recognized revenue, partially offset by a $0.2 million increase in accounts payable, a $0.8 million increase in accrued compensation and related benefits, a $0.1 million increase in accrued and other liabilities and a $0.4 million increase in deferred revenue.  The $7.1 million combined cash flow decrease resulted from the increase in accounts receivable and decrease in combined billings in excess of recognized revenues and deferred revenue due to the timing of billing milestones and payments received.

Investing Activities
 
Cash flows used in investing activities for the three months ended March 31, 2013 of $1.2 million consisted of payment for capital expenditures. Cash flows used in investing activities of $0.1 million for the three months ended March 31, 2012 consisted of payments for capital expenditures.

Financing Activities

Cash flows provided by financing activities of $2.5 million for the three months ended March 31, 2013 consisted primarily of $1.2 million of proceeds from the exercise of stock options, $0.5 million of proceeds from our Employee Stock Purchase Plan and $0.8 million of excess tax benefit from stock-based compensation.

Cash flows provided by financing activities of $1.1 million for the year ended March 31, 2012 consisted primarily of $0.6 million proceeds from the exercise of stock options and $0.5 million proceeds from our Employee Stock Purchase Plan.


Liquidity

As of March 31, 2013, our working capital, defined as total current assets less total current liabilities, was $94.3 million, compared with $82.9 million as of December 31, 2012. Cash and cash equivalents were $63.2 million as of March 31, 2013, compared to $61.6 million as of December 31, 2012.  As of March 31, 2013 and December 31, 2012, cash and cash equivalents held by our foreign subsidiaries were $2.1 million and $2.0 million, respectively.  We anticipate that our overall expenses, as well as planned capital expenditures, may constitute a material use of our cash resources. In addition, we may use cash resources to repurchase common stock or fund potential investments in, or acquisitions of complementary products, technologies or businesses. 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 at least the next twelve months. However, in the event that during such period, or thereafter, we are not successful in generating sufficient cash flows from operations we may need to raise additional capital through private or public financings, strategic relationships or other arrangements, which may not be available to us on acceptable terms or at all.
  

Off-Balance Sheet Agreements

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

 
21

 
 
We indemnify certain customers from third-party claims of intellectual property infringement relating to the use of our products. Historically, costs related to these guarantees of indemnification have not been significant. We are unable to estimate the maximum potential impact of these guarantees on our future results of operations.

Contractual Obligations

The following table summarizes our known contractual obligations (in thousands):
 
   
Payments Due by Period
 
Contractual
Obligations (1)
 
2013
(remaining
nine
months)
   
2014
   
2015
   
2016
   
2017
 
Thereafter
   
Total
 
Operating lease obligations (2)
  $
1,015
    $
1,691
    $
1,561
    $
1,563
    $
1,289
  $  
695
   
$
7, 814
 
 

 
(1)
The contractual obligation table above excludes liabilities for uncertain tax positions of $2.9 million, which are not practicable to assign to any particular years, due to the inherent uncertainty of the tax positions.  See Note 6 of “Notes to Consolidated Financial Statements” for further discussion.

 
(2)
The operating lease obligations have been reduced by future minimum sublease rental income of $0.2 million in the remaining nine months in 2013. 
 

Item 3. Quantitative and Qualitative Disclosures 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 March 31, 2013, we had cash and cash equivalents of $63.2 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 March 31, 2013 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. The effect of an immediate 10% adverse change in exchange rates on foreign denominated payables as of March 31, 2013 would result in a loss of approximately $0.7 million. As of March 31, 2013, we did not have outstanding hedging contracts, although we may enter into such contracts in the future. We intend to monitor our foreign currency exposure. Future exchange rate fluctuations may have a material negative impact on our business.

 
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 controls and procedures" as defined in Exchange Act Rules 13a-15(e) and 15d-15(e) as of March 31, 2013 in connection with the filing of this Quarterly Report on Form 10-Q. Based on that evaluation as of March 31, 2013, 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.
   
 
22

 
 
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 March 31, 2013 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. With respect to the matter below, we determined a potential loss was not probable as of March 31, 2013 and, accordingly, no amount was accrued at such time.
 
Philip Steven Melman filed a complaint against us and our Chief Executive Officer on December 7, 2009 in the Superior Court for Santa Clara County.  In the complaint, Mr. Melman alleged wrongful discharge based on discrimination, fraud, breach of contract and similar theories, in connection with the termination of Mr. Melman's employment with us.  The complaint sought compensatory and punitive damages, any other available remedies, as well as attorney's fees and costs. Summary judgment in the favor of both the Company and Dr. Kibarian was entered by the court on October 27, 2011 and November 15, 2011, respectively.  Mr. Melman appealed both orders in the Sixth District Court of Appeal in Santa Clara County. On March 22, 2013, the Court released its opinion affirming in full the grant of summary judgment in favor of the Company and Dr. Kibarian, which decision became final on April 22, 2013.
 

Item 1A. Risk Factors
 
Item 1A,“Risk Factors,” on pages 9 through 16 of the Company’s Annual Report on Form 10-K for the year ended December 31, 2012, 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) of our common stock during the three months March 31, 2013 (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
(2)
   
Approximate
Dollar
Value of
Shares that
May Yet Be
Purchased
Under
Programs(2)
 
Month #1 (January 1, 2013 through January 31, 2013)
   
   
$
     
   
$
19,522
 
Month #2 (February 1, 2013 through February 28, 2013)
   
1
    $
15.19
     
   
$
19,522
 
Month #3 (March 1, 2013 through March 31, 2013)
   
    $
     
   
$
19,522
 
Total
   
1
   
$
15.19
     
         
 
 

 
(1)
Included in the shares indicated in the table above are shares that the Company withheld through net share settlements to cover tax withholding obligations upon the vesting of restricted stock unit awards under the Company’s equity compensation plans.
 
(2)
On October 29, 2007, the Board of Directors adopted a program to repurchase up to $10.0 million of the Company’s common stock on the open market. The initial program was for three years, but on October 19, 2010, the Board of Directors authorized an extension of, and an increase in, the program and the aggregate amount available to repurchase between October 19, 2010 and October 29, 2012 was reset to an additional $10.0 million of the Company’s common stock, meaning a total of $19.3 million was available. The program expired on October 29, 2012. As of the expiration date on October 29, 2012, 3.8 million shares had been repurchased at the average price of $4.53 per share, a total purchase price of $17.0 million, under this program. On November 8, 2012, the Board of Directors adopted a new program to repurchase up to $20.0 million of the Company’s common stock on the open market over the next two years. As of March 31, 2013, 36,100 shares had been repurchased at the average price of $13.23 per share under this new program, a total purchase price of $0.5 million and $19.5 million remained for future repurchases.
 
23

 
 
Item 3. Defaults Upon Senior Securities

None

 
Item 4. Mine Safety Disclosures

None
 
 
Item 5. Other Information

None
 
 
24

 
 
Item 6. Exhibits

Exhibit
Number
 
 
Description
     
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. ††
 
 

 *
As contemplated by SEC Release No. 33-8212, these exhibits are furnished with this Quarterly Report on Form 10-Q and are not deemed filed with the Securities and Exchange Commission and are not incorporated by reference in any filing of PDF Solutions, Inc. under the Securities Act of 1933 or the Securities Exchange Act of 1934, whether made before or after the date hereof and irrespective of any general incorporation language in any filings.

††
In accordance with Rule 406T of Regulation S-T, the interactive data files on Exhibit 101 hereto are deemed not filed or part of a registration statement or prospectus for purposes of Sections 11 or 12 of the Securities Act of 1933, as amended, are deemed not filed for purposes of Section 18 of the Securities and Exchange Act of 1934, as amended, and otherwise are not subject to liability under those sections.
 
 
25

 
 
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: May 8, 2013
By:
/s/ JOHN K. KIBARIAN
 
   
John K. Kibarian
 
   
President and Chief Executive Officer
 
   
(principal executive officer)
 


Date: May 8, 2013
By:
/s/ GREGORY C. WALKER
 
   
Gregory C. Walker
 
   
Vice President, Finance and Chief Financial Officer
 
   
(principal financial and accounting officer)
 
 
 
26

 
 
INDEX TO EXHIBITS

Exhibit
Number
 
 
Description
     
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. ††
 
 

 *
As contemplated by SEC Release No. 33-8212, these exhibits are furnished with this Quarterly Report on Form 10-Q and are not deemed filed with the Securities and Exchange Commission and are not incorporated by reference in any filing of PDF Solutions, Inc. under the Securities Act of 1933 or the Securities Exchange Act of 1934, whether made before or after the date hereof and irrespective of any general incorporation language in any filings.
 
††
In accordance with Rule 406T of Regulation S-T, the interactive data files on Exhibit 101 hereto are deemed not filed or part of a registration statement or prospectus for purposes of Sections 11 or 12 of the Securities Act of 1933, as amended, are deemed not filed for purposes of Section 18 of the Securities and Exchange Act of 1934, as amended, and otherwise are not subject to liability under those sections.
 
 
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