10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 10-Q

☑	QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934
	For the Quarterly Period ended March 31, 2022

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 Incorporation or Organization)	(I.R.S. Employer Identification No.)
2858 De La Cruz Blvd.
Santa Clara, California	95050
(Address of Principal Executive Offices)	(Zip Code)

(408) 280-7900

(Registrant’s Telephone Number, Including Area Code)

Securities registered pursuant to Section 12(b) of the Act:

Title of each class	Trading Symbol(s)	Name of each exchange on which registered
Common Stock, $0.00015 par value	PDFS	The Nasdaq Stock Market LLC

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

Indicate by check mark whether the registrant has submitted electronically every Interactive Data File required to be submitted 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 such files). Yes ☑ No  ☐

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

Large accelerated filer ☐	Accelerated filer ☐
Non-accelerated  filer ☑	Smaller reporting company ☑
	Emerging growth company ☐

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

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

There were 36,956,426 shares of the Registrant’s Common Stock outstanding as of May 6, 2022.

TABLE OF CONTENTS

	Page
PART I   FINANCIAL INFORMATION
Item 1. Financial Statements (Unaudited)
Condensed Consolidated Balance Sheets	3
Condensed Consolidated Statements of Comprehensive Loss	4
Condensed Consolidated Statements of Stockholders’ Equity	5
Condensed Consolidated Statements of Cash Flows	6
Notes to Condensed Consolidated Financial Statements	8
Item 2. Management’s Discussion and Analysis of Financial Condition and Results of Operations	25
Item 3. Quantitative and Qualitative Disclosures About Market Risk	36
Item 4. Controls and Procedures	36
PART II  OTHER INFORMATION
Item 1. Legal Proceedings	37
Item 1A. Risk Factors	37
Item 2. Unregistered Sales of Equity Securities and Use of Proceeds	37
Item 3. Defaults Upon Senior Securities	38
Item 4. Mine Safety Disclosures	38
Item 5. Other Information	38
Item 6. Exhibits	39
INDEX TO EXHIBITS	39
SIGNATURES	40

2

PART I — FINANCIAL INFORMATION

Item 1. Financial Statements

PDF SOLUTIONS, INC.

CONDENSED CONSOLIDATED BALANCE SHEETS

(unaudited)

(in thousands, except par value)

	March 31,		December 31,
	2022		2021
ASSETS
Current assets:
Cash and cash equivalents	$	35,799	$	27,684
Short-term investments		98,443		112,542
Accounts receivable, net of allowance for doubtful accounts of $902 and $890 in 2022 and 2021, respectively		37,753		40,087
Prepaid expenses and other current assets		8,857		8,194
Total current assets		180,852		188,507
Property and equipment, net		36,844		35,295
Operating lease right-of-use assets, net		4,479		5,408
Goodwill		14,123		14,123
Intangible assets, net		20,372		21,239
Deferred tax assets, net		67		75
Other non-current assets		8,840		9,121
Total assets	$	265,577	$	273,768
LIABILITIES AND STOCKHOLDERS’ EQUITY
Current liabilities:
Accounts payable	$	4,053	$	5,554
Accrued compensation and related benefits		8,576		9,495
Accrued and other current liabilities		4,602		3,328
Operating lease liabilities – current portion		1,225		1,758
Deferred revenues – current portion		23,868		23,691
Billings in excess of recognized revenues		245		—
Total current liabilities		42,569		43,826
Long-term income taxes payable		2,666		2,656
Non-current operating lease liabilities		4,741		5,258
Other non-current liabilities		2,034		2,443
Total liabilities		52,010		54,183
Commitments and contingencies (Note 12)
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 47,929 and 47,414, respectively; shares outstanding 37,594 and 37,411, respectively		6		6
Additional paid-in-capital		430,799		423,069
Treasury stock at cost, 10,335 and 10,003 shares, respectively		(113,872)		(104,705)
Accumulated deficit		(101,871)		(97,721)
Accumulated other comprehensive loss		(1,495)		(1,064)
Total stockholders’ equity		213,567		219,585
Total liabilities and stockholders’ equity	$	265,577	$	273,768

See accompanying Notes to Condensed Consolidated Financial Statements (unaudited)

3

PDF SOLUTIONS, INC.

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS

(unaudited)

(in thousands, except per share amounts)

	Three Months Ended March 31,
	2022		2021
Revenues:
Analytics	$	30,426	$	19,393
Integrated Yield Ramp		3,072		4,807
Total revenues		33,498		24,200
Costs and Expenses:
Costs of revenues		11,529		10,663
Research and development		14,089		10,841
Selling, general and administrative		10,839		9,464
Amortization of acquired intangible assets		314		314
Interest and other expense (income), net		(310)		(441)
Loss before income taxes		(2,963)		(6,641)
Income tax expense		1,187		956
Net loss	$	(4,150)	$	(7,597)
Other comprehensive loss:
Foreign currency translation adjustments, net of tax		(397)		(530)
Change in unrealized losses related to available-for-sale debt securities, net of tax		(34)		2
Total other comprehensive income loss		(431)		(528)
Comprehensive loss	$	(4,581)	$	(8,125)
Net loss per share, basic and diluted	$	(0.11)	$	(0.21)
Weighted average common shares used to calculate net loss per share, basic and diluted		37,606		36,974

See accompanying Notes to Condensed Consolidated Financial Statements (unaudited)

4

PDF SOLUTIONS, INC.

CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS’ EQUITY

(unaudited)

(in thousands)

	Three Months Ended March 31, 2022
											Accumulated
				Additional							Other		Total
	Common Stock			Paid-In		Treasury Stock			Accumulated		Comprehensive		Stockholders’
	Shares	Amount		Capital		Shares	Amount		Deficit		Loss		Equity
Balances, December 31, 2021	37,411	$	6	$	423,069	10,003	$	(104,705)	$	(97,721)	$	(1,064)	$	219,585
Issuance of common stock in connection with employee stock purchase plan	95		—		1,502	—		—		—		—		1,502
Issuance of common stock in connection with exercise of options	75		—		675	—		—		—		—		675
Vesting of restricted stock units	232		—		—	—		—		—		—		—
Purchases of treasury stock in connection with tax withholdings on restricted stock grants	—		—		—	113		(3,389)		—		—		(3,389)
Repurchase of common stock	(219)		—		—	219		(5,778)		—		—		(5,778)
Stock-based compensation expense	—		—		5,553	—		—		—		—		5,553
Comprehensive loss	—		—		—	—		—		(4,150)		(431)		(4,581)
Balances, March 31, 2022	37,594	$	6	$	430,799	10,335	$	(113,872)	$	(101,871)	$	(1,495)	$	213,567

	Three Months Ended March 31, 2021
											Accumulated
				Additional							Other		Total
	Common Stock			Paid-In		Treasury Stock			Accumulated		Comprehensive		Stockholders’
	Shares	Amount		Capital		Shares	Amount		Deficit		Loss		Equity
Balances, December 31, 2020	36,850	$	6	$	407,173	9,550	$	(96,215)	$	(76,233)	$	(225)	$	234,506
Issuance of common stock in connection with employee stock purchase plan	100		—		921	—		—		—		—		921
Issuance of common stock in connection with exercise of options	81		—		568	—		—		—		—		568
Vesting of restricted stock units	149		—		—	—		—		—		—		—
Purchases of treasury stock in connection with tax withholdings on restricted stock grants	—		—		—	73		(1,463)		—		—		(1,463)
Repurchase of common stock	(251)		—		—	251		(4,523)		—		—		(4,523)
Stock-based compensation expense	—		—		3,369	—		—		—		—		3,369
Comprehensive loss	—		—		—	—		—		(7,597)		(528)		(8,125)
Balances, March 31, 2021	36,929	$	6	$	412,031	9,874	$	(102,201)	$	(83,830)	$	(753)	$	225,253

See accompanying Notes to Condensed Consolidated Financial Statements (unaudited)

5

PDF SOLUTIONS, INC.

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS

(unaudited)

(in thousands)

	Three Months Ended March 31,
	2022		2021
Cash flows from operating activities:
Net loss	$	(4,150)	$	(7,597)
Adjustments to reconcile net loss to net cash provided by (used in) operating activities:
Depreciation and amortization		1,380		1,718
Stock-based compensation expense		5,553		3,369
Amortization of acquired intangible assets		867		849
Amortization of costs capitalized to obtain revenue contracts		173		165
Loss on disposal and write-down in value of property and equipment		—		5
Deferred taxes		(11)		55
Other		37		(20)
Changes in operating assets and liabilities:
Accounts receivable		2,296		(677)
Prepaid expenses and other current assets		(976)		2,839
Operating lease right-of-use assets		918		476
Other non-current assets		278		339
Accounts payable		(2,069)		(4,109)
Accrued compensation and related benefits		(864)		(2,059)
Accrued and other liabilities		582		(162)
Deferred revenues		(225)		(1,994)
Billings in excess of recognized revenues		245		(998)
Operating lease liabilities		(1,038)		(524)
Net cash provided by (used in) operating activities		2,996		(8,325)
Cash flows from investing activities:
Proceeds from maturities and sales of short-term investments		35,000		68,000
Purchases of short-term investments		(20,959)		(10,997)
Purchases of property and equipment		(1,765)		(586)
Net cash provided by investing activities		12,276		56,417
Cash flows from financing activities:
Proceeds from exercise of stock options		675		568
Proceeds from employee stock purchase plan		1,502		921
Payments for taxes related to net share settlement of equity awards		(3,389)		(1,463)
Repurchases of common stock		(5,778)		(4,523)
Net cash used in financing activities		(6,990)		(4,497)
Effect of exchange rate changes on cash and cash equivalents		(167)		(104)
Net change in cash, cash equivalents, and restricted cash		8,115		43,491
Cash, cash equivalents, and restricted cash at beginning of period		27,684		33,815
Cash, cash equivalents, and restricted cash at end of period	$	35,799	$	77,306
Reconciliation of cash, cash equivalents, and restricted cash to the balance sheets:
Cash and cash equivalents	$	35,799	$	74,287
Restricted cash		—		3,019
Total cash, cash equivalents, and restricted cash	$	35,799	$	77,306

Continued on next page.

6

PDF SOLUTIONS, INC.

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS – CONTINUED

(unaudited)

(in thousands)

	Three Months Ended March 31,
	2022		2021
Supplemental disclosure of cash flow information:
Cash paid during the period for taxes	$	1,254	$	530
Cash paid for amounts included in the measurement of operating lease liabilities	$	430	$	651
Supplemental disclosure of noncash information:
Property and equipment received and accrued in accounts payable and accrued and other liabilities	$	1,923	$	181
Advances for purchase of fixed assets transferred from prepaid assets to property and equipment	$	120	$	—
Release of restricted cash reducing goodwill due to the acquisition purchase price adjustment	$	—	$	469

See accompanying Notes to Condensed Consolidated Financial Statements (unaudited)

7

PDF SOLUTIONS, INC.

NOTES TO CONDENSED CONSOLIDATED FINANCIAL STATEMENTS (UNAUDITED)

1. BASIS OF PRESENTATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

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, 2021.

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

The condensed consolidated balance sheet at December 31, 2021, has been derived from the audited consolidated financial statements but does not include all disclosures required by accounting principles generally accepted in the United States of America.

Use of Estimates

The preparation of financial statements in conformity with generally accepted accounting principles in the United States (“U.S. GAAP”) requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Significant estimates in these financial statements include revenue recognition, the estimated useful lives of property and equipment and intangible assets, assumptions made in analysis of allowance for doubtful accounts, fair values of assets acquired and liabilities assumed in business combinations, impairment of goodwill and long-lived assets, valuation for deferred tax assets, and accounting for lease obligations, stock-based compensation expense, and income tax uncertainties and contingencies. Actual results could differ from those estimates and may result in material effects on the Company’s operating results and financial position.

The global COVID-19 pandemic has impacted the operations and purchasing decisions of companies worldwide. As of the date of issuance of the condensed consolidated financial statements, the Company is not aware of any specific event or circumstance relating to COVID-19 that would require updates to the Company’s estimates and judgments or revisions to the carrying value of its assets or liabilities. These estimates may change, as new events occur and additional information is obtained, and are recognized in the condensed consolidated financial statements as soon as they become known. Actual results could differ from those estimates and any such differences may be material to the financial statements.

Recent Accounting Standards

Accounting Standards Adopted

Management has reviewed recently issued accounting pronouncements and has determined there are not any that would have a material impact on the condensed consolidated financial statements.

8

Accounting Standards Not Yet Adopted

In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments – Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments (ASU 2016-13), which requires measurement and recognition of expected credit losses for financial assets held at the reporting date based on internal information, external information, or a combination of both relating to past events, current conditions, and reasonable and supportable forecasts. ASU No. 2016-13 replaces the existing incurred loss impairment model with a forward-looking expected credit loss model, which will result in earlier recognition of credit losses. Subsequent to the issuance of ASU No. 2016-13, the FASB issued ASU No. 2018-19, Codification Improvements to Topic 326, Financial Instruments – Credit Losses, ASU No. 2019-04, Codification Improvements to Topic 326, Financial Instruments – Credit Losses, Topic 815, Derivatives and Hedging, and Topic 825, Financial Instrument, ASU No. 2019-05, Financial Instruments – Credit Losses (Topic 326) Targeted Transition Relief, ASU No. 2016-13, ASU No. 2019-10 Financial Instruments-Credit Losses (Topic 326), Derivatives and Hedging (Topic 815), and Leases (Topic 842), and ASU No. 2019-11 Codification Improvements to Topic 326, Financial Instruments-Credit Losses. The subsequent ASUs do not change the core principle of the guidance in ASU No. 2016-13. Instead, these amendments are intended to clarify and improve operability of certain topics included within ASU No. 2016-13.

Additionally, ASU No. 2019-10 defers the effective date for the adoption of the new standard on credit losses for public filers that are considered small reporting companies (“SRC”) as defined by the SEC to fiscal years beginning after December 15, 2022, including interim periods within those fiscal years, which will be fiscal 2023 for the Company if it continues to be classified as an SRC. In February 2020, the FASB issued ASU 2020-02, which provides guidance regarding methodologies, documentation, and internal controls related to expected credit losses. The subsequent amendments will have the same effective date and transition requirements as ASU No. 2016-13. Early adoption is permitted. Topic 326 requires a modified retrospective approach by recording a cumulative-effect adjustment to retained earnings as of the beginning of the period of adoption. While the Company is currently evaluating the impact of Topic 326, the Company does not expect the adoption of this ASU to have a material impact on its condensed consolidated financial statements or the related disclosure.

In August 2020, the FASB issued ASU No. 2020-06, Debt – Debt with Conversion and Other Options (Subtopic 470-20) and Derivatives and Hedging – Contracts in Entity’s Own Equity (Subtopic 815-20): Accounting for Convertible Instruments and Contracts in an Entity’s Own Equity, which is intended to simplify the accounting for certain financial instruments with characteristics of liabilities and equity, including convertible instruments and contracts on an entity’s own equity. The guidance allows for either full retrospective adoption or modified retrospective adoption. Additionally, the ASU will require entities to use the “if-converted” method when calculating diluted earnings per share for convertible instruments. The ASU will be effective for annual reporting periods beginning after December 15, 2023 for SRCs and interim periods within those annual periods. Early adoption is permitted. The Company does not anticipate that the adoption of this ASU will have a significant impact on its condensed consolidated financial statements or the related disclosures.

Management has reviewed other recently issued accounting pronouncements issued or proposed by the FASB, and does not believe any of these accounting pronouncements has had or will have a material impact on the condensed consolidated financial statements.

2. REVENUE FROM CONTRACTS WITH CUSTOMERS

The Company derives revenue from two sources: Analytics revenue and Integrated Yield Ramp revenue.

The Company recognizes revenue in accordance with FASB ASC Topic 606, Revenue from Contracts with Customers, and its related amendments (collectively known as “ASC 606”). ASC 606 outlines a single comprehensive model to use in accounting for revenue arising from contracts with customers. Revenue is recognized when control of products or services is transferred to customers, in an amount that reflects the consideration the Company expects to be entitled to in exchange for those promised products or services.

The Company determines revenue recognition through the following five steps:

● Identification of the contract, or contracts, with a customer

● Identification of the performance obligations in the contract

9

● Determination of the transaction price

● Allocation of the transaction price to the performance obligations in the contract

● Recognition of revenue when, or as, performance obligations are satisfied

The Company accounts for a contract when it has approval and commitment from both parties, the rights of the parties are identified, payment terms are identified, the contract has commercial substance, and collectability of consideration is probable.

Contracts with multiple performance obligations

The Company enters into contracts that can include various combinations of licenses, products and services, some of which are distinct and are accounted for as separate performance obligations. For contracts with multiple performance obligations, the Company allocates the transaction price of the contract to each performance obligation on a relative basis using the standalone selling price (“SSP”).

Analytics Revenue

Analytics revenue is derived from the following primary offerings: licenses and services for standalone software (which is primarily Exensio^® and Cimetrix^® products), SaaS (which is primarily Exensio products), and DFI™ systems and CV^® systems that do not include performance incentives based on customers’ yield achievement.

Revenue from standalone software is recognized depending on whether the license is perpetual or time-based. Perpetual (one-time charge) license software is recognized at the time of the inception of the arrangement when control transfers to the customers, if the software license is considered as a separate performance obligation from the services offered by the Company. Revenue from post-contract support is recognized over the contract term on a straight-line basis, because we are providing (i) support and (ii) unspecified software updates on a when-and-if available basis over the contract term. Revenue from time-based-licensed software is allocated to each performance obligation and is recognized either at a point in time or over time as follows. The license component is recognized at the time when control transfers to customers, with the post-contract support component recognized ratably over the committed term of the contract. For contracts with any combination of licenses, support, and other services, distinct performance obligations are accounted for separately. For contracts with multiple performance obligations, we allocate the transaction price of the contract to each performance obligation on a relative basis using the SSP attributed to each performance obligation.

Revenue from SaaS arrangements, which allow for the use of a cloud-based software product or service over a contractually determined period of time without the customer having to take possession of software, is accounted for as a subscription and is recognized as revenue ratably, on a straight-line basis, over the subscription period beginning on the date the service is first made available to customers. For contracts with any combination of SaaS and related services, distinct performance obligations are accounted for separately. For contracts with multiple performance obligations, we allocate the transaction price of the contract to each performance obligation on a relative basis using the SSP attributed to each performance obligation.

Revenue from DFI systems and CV systems that do not include performance incentives based on customers’ yield achievement is recognized primarily as services are performed. Where there are distinct performance obligations, the Company allocates revenue to all deliverables based on their SSPs. For those contracts with multiple performance obligations, the Company allocates the transaction price of the contract to each performance obligation on a relative basis using the SSP attributed to each performance obligation. Where there are not discrete performance obligations, historically, revenue is primarily recognized as services are performed using a percentage of completion method based on costs or labor-hours inputs, whichever is the most appropriate measure of the progress towards completion of the contract. The estimation of percentage of completion method is complex and subject to many variables that require significant judgement. Please refer to “Significant Judgments” section of this Note for further discussion.

10

Integrated Yield Ramp Revenue

Integrated Yield Ramp revenue is derived from the Company’s fixed-fee engagements that include performance incentives based on customers’ yield achievement (which consists primarily of Gainshare royalties) typically based on customer’s wafer shipments, pertaining to these fixed-price contracts, which royalties are variable.

Revenue under these project–based contracts, which are delivered over a specific period of time, typically for a fixed fee component paid on a set schedule, is recognized as services are performed using a percentage of completion method based on costs or labor-inputs, whichever is the most appropriate measure of the progress towards completion of the contract. Where there are distinct performance obligations, the Company allocates revenue to all deliverables based on their SSPs and allocates the transaction price of the contract to each performance obligation on a relative basis using SSP. Similar to the services provided in connection with DFI systems and CV systems that are contributing to Analytics revenue, due to the nature of the work performed in these arrangements, the estimation of percentage of completion method is complex and subject to many variables that require significant judgement. Please refer to “Significant Judgments” section of this Note for further discussion.

The Gainshare royalty contained in IYR contracts is a variable fee related to continued usage of the Company’s intellectual property after the fixed-fee service period ends, based on a customer’s yield achievement. Revenue derived from Gainshare is contingent upon the Company’s customers reaching certain defined production yield levels. Gainshare royalty periods are generally subsequent to the delivery of all contractual services and performance obligations. The Company records Gainshare as a usage-based royalty derived from customers’ usage of intellectual property and records it in the same period in which the usage occurs.

Disaggregation of Revenue

The Company disaggregates revenue from contracts with customers into the timing of the transfer of goods and services and the geographical regions. The Company determined that disaggregating revenue into these categories achieves the disclosure objective to depict how the nature, amount, timing, and uncertainty of revenue and cash flows are affected by economic factors.

The Company’s performance obligations are satisfied either over time or at a point-in-time. The following table represents a disaggregation of revenue by timing of revenue:

	Three Months Ended March 31,
	2022		2021
Over time	70	%	50	%
Point-in-time	30	%	50	%
Total	100	%	100	%

International revenues accounted for approximately 48% and 65% of our total revenues during the three months ended March 31, 2022 and March 31, 2021, respectively. See Note 10, Customer and Geographic Information.

Significant Judgments

Judgments and estimates are required under ASC 606. Due to the complexity of certain contracts, the actual revenue recognition treatment required under ASC 606 for the Company’s arrangements may be dependent on contract-specific terms and may vary in some instances.

For revenue under project-based contracts for fixed-price implementation services, revenue is recognized as services are performed using a percentage-of-completion method based on costs or labor-hours input method, whichever is the most appropriate measure of the progress towards completion of the contract. Due to the nature of the work performed in these arrangements, the estimation of percentage of completion method is complex, subject to many variables and requires significant judgment. Key factors reviewed by the Company to estimate costs to complete each contract are future labor and product costs and expected productivity efficiencies. If circumstances arise that change the original estimates of revenues,

11

costs, or extent of progress toward completion, revisions to the estimates are made. These revisions may result in increases or decreases in estimated revenues or costs, and such revisions are reflected in revenue on a cumulative catch-up basis in the period in which the circumstances that gave rise to the revision become known.

The Company’s contracts with customers often include promises to transfer products, licenses software and provide services, including professional services, technical support services, and rights to unspecified updates to a customer. Determining whether licenses and services are distinct performance obligations that should be accounted for separately, or not distinct and thus accounted for together, requires significant judgment. The Company rarely licenses software on a standalone basis, so the Company is required to estimate the range of SSPs for each performance obligation. In instances where SSP is not directly observable because the Company does not license the software or sell the service separately, the Company determines the SSP using information that may include market conditions and other observable inputs.

The Company is required to record Gainshare royalty revenue in the same period in which the usage occurs. Because the Company generally does not receive the acknowledgment reports from its customers during a given quarter within the time frame necessary to adequately review the reports and include the actual amounts in quarterly results for such quarter, the Company accrues the related revenue based on estimates of customers underlying sales achievement. The Company’s estimation process can be based on historical data, trends, seasonality, changes in the contract rate, knowledge of the changes in the industry and changes in the customer’s manufacturing environment learned through discussions with customers and sales personnel. As a result of accruing revenue for the quarter based on such estimates, adjustments will be required in the following quarter to true-up revenue to the actual amounts reported.

Contract Balances

The Company performs its obligations under a contract with a customer by licensing software or providing services in exchange for consideration from the customer. The timing of the Company’s performance often differs from the timing of the customer’s payment, which results in the recognition of a receivable, a contract asset or a contract liability.

The Company classifies the right to consideration in exchange for software or services transferred to a customer as either a receivable or a contract asset. A receivable is a right to consideration that is unconditional, as compared to a contract asset, which is a right to consideration that is conditional upon factors other than the passage of time. The majority of the Company’s contract assets represent unbilled amounts related to fixed-price service contracts when the revenue recognized exceeds the amount billed to the customer. The contract assets are generally classified as current and are recorded on a net basis with deferred revenue (i.e. contract liabilities) at the contract level. At March 31, 2022 and December 31, 2021, the total contract assets included in prepaid expenses and other current assets in the Condensed Consolidated Balance Sheets $0.4 million and $0.4 million, respectively. The Company did not record any asset impairment charges related to contract assets for the periods presented.

Deferred revenues consist substantially of amounts invoiced in advance of revenue recognition and are recognized as the revenue recognition criteria are met. Deferred revenues that will be recognized during the succeeding twelve-month period are recorded as current deferred revenues and the remaining portion is recorded in the other non-current liabilities in the Condensed Consolidated Balance Sheets. At March 31, 2022 and December 31, 2021, the non-current portion of deferred revenues included in non-current liabilities was $2.0 million and $2.4 million, respectively. Revenue recognized that was included in the deferred revenues and billings in excess of recognized revenues balances at the beginning of each reporting period was $6.9 million and $6.3 million during the three months ended March 31, 2022 and 2021, respectively.

At March 31, 2022, the aggregate amount of the transaction price allocated to the remaining performance obligations related to customer contracts that were unsatisfied or partially unsatisfied was approximately $196.8 million. Given the applicable contract terms with customers, the majority of this amount is expected to be recognized as revenue over the next two years, with the remainder in the following three years. This amount does not include insignificant contracts to which the customer is not committed, nor significant contracts for which we recognize revenue equal to the amount we have the right to invoice for services performed, or future sales-based or usage-based royalty payments in exchange for a license of intellectual property. This amount is subject to change due to future revaluations of variable consideration, terminations, other contract modifications, or currency adjustments. The estimated timing of the recognition of remaining unsatisfied performance

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obligations is subject to change and is affected by changes to the scope, change in timing of delivery of products and services, or contract modifications.

The adjustment to revenue recognized from performance obligations satisfied (or partially satisfied) in previous periods was an increase of $0.2 million and a decrease $0.3 million during the three months ended March 31, 2022 and 2021, respectively. These amounts primarily represent changes in estimated percentage-of-completion based contracts and changes in actual versus estimated Gainshare royalty.

Costs to obtain or fulfill a contract

The Company capitalizes the incremental costs to obtain or fulfill a contract with a customer, including direct sales commissions and related fees, when it expects to recover those costs. Amortization expense related to these capitalized costs is recognized over the period associated with the revenue from which the cost was incurred. Total capitalized direct sales commission costs included in prepaid expenses and other current assets in the accompanying Condensed Consolidated Balance Sheets as of March 31, 2022, and December 31, 2021, were $0.9 million and $0.6 million, respectively. Total capitalized direct sales commission costs included in other non-current assets in the accompanying Condensed Consolidated Balance Sheets as of March 31, 2022, and December 31, 2021, were $2.1 million and $2.1 million, respectively. Amortization of these assets were $0.2 million and $0.2 million during the three months ended March 31, 2022 and 2021, respectively. There was no impairment loss in relation to the costs capitalized for the periods presented.

Practical expedient

The Company does not adjust the transaction price for the effects of a significant financing component when the period between the transfers of the promised good or service to the customer and payment for that good or service by the customer is expected to be one year or less. The Company assessed each of its revenue generating arrangements in order to determine whether a significant financing component exists, and determined its contracts did not include a significant financing component during the three months ended March 31, 2022 and 2021.

3. STRATEGIC PARTNERSHIP AGREEMENT WITH ADVANTEST AND RELATED PARTY TRANSACTIONS

On July 29, 2020, the Company entered into a long-term strategic partnership with Advantest Corporation through its wholly-owned subsidiary, Advantest America, Inc. (collectively referred to herein as “Advantest”) that included the following agreements.

● A Securities Purchase Agreement for the purchase by Advantest of an aggregate of 3,306,924 shares of the Company’s common stock for aggregate gross proceeds of $65.2 million and a related Stockholder Agreement.

● An Amendment #1 to that certain Software License and Related Services Agreement, dated as of March 25, 2020, for an exclusive commercial arrangement in which the Company and Advantest collaborate on, and the Company initially hosts, develops and maintains, an Advantest-specific cloud layer on the Exensio platform.

● An Amended and Restated Master Development Agreement with Advantest, pursuant to which the Company and Advantest agreed to collaborate on extensions to or combinations of both of their existing technology and new technology to address mutual customers’ needs through one or more development phases subject to certain conditions as set forth therein. Costs and expenses incurred related to this agreement have not been significant for the three months ended March 31, 2022 and 2021.

● A Master Commercial Terms and Support Services Agreement for the commercialization and support of integrated products of the Company and Advantest that are the outcome of the above development agreement. No material costs and expenses were incurred related to the Commercial Agreement with Advantest during the three months ended March 31, 2022 and 2021.

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Analytics revenue recognized from Advantest was $2.6 million during the three months ended March 31, 2022 and $2.6 million during the three months ended March 31, 2021. There were no outstanding accounts receivable from Advantest as of March 31, 2022, and December 31, 2021, and deferred revenue amounted to $4.2 million and $6.8 million as of March 31, 2022 and December 31, 2021, respectively. There was no occurrence of any termination events under these agreements as of the issuance of these condensed consolidated financial statements.

The Company carries out transactions with Advantest on arm’s length commercial customary terms.

4. BALANCE SHEET COMPONENTS

Accounts receivable

Accounts receivable include amounts that are unbilled at the end of the period that are expected to be billed and collected within a 12-month period. Unbilled accounts receivable, included in accounts receivable, totaled $10.8 million and $11.8 million as of March 31, 2022, and December 31, 2021, respectively. Unbilled accounts receivable that are not expected to be billed and collected during the succeeding 12-month period is recorded in other non-current assets and totaled $1.3 million and $1.3 million as of March 31, 2022, and December 31, 2021, respectively.

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

Property and equipment

Property and equipment, net consist of the following (in thousands):

	March 31,		December 31,
	2022		2021
Computer equipment	$	11,887	$	11,924
Software		5,411		5,419
Furniture, fixtures and equipment		2,503		2,506
Leasehold improvements		6,266		6,272
Laboratory and other equipment		4,171		3,981
Test equipment		28,060		24,452
Construction-in-progress		21,263		22,158
		79,561		76,712
Less: accumulated depreciation and amortization		(42,717)		(41,417)
Total	$	36,844	$	35,295

Test equipment includes DFI systems assets at customer sites that are contributing to revenue. The construction-in-progress balance related to construction of DFI™ systems assets totaled $18.5 million and $20.0 million as of March 31, 2022, and December 31, 2021, respectively. Depreciation and amortization expense was $1.4 million and $1.7 million during the three months ended March 31, 2022 and 2021, respectively.

In the fourth quarter of 2021, the Company wrote down the value of its property and equipment by $3.2 million related to its first-generation of e-beam tools for DFI™ systems wherein carrying values may not be fully recoverable due to lack of market demand and future needs of our customers for these tools.

Goodwill and Intangible Assets, Net

As of March 31, 2022, and December 31, 2021, the carrying amount of goodwill was $14.1 million.

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Intangible assets, net, consisted of the following (in thousands):

		March 31, 2022						December 31, 2021
	Amortization	Gross				Net		Gross				Net
	Period	Carrying		Accumulated		Carrying		Carrying		Accumulated		Carrying
	(Years)	Amount		Amortization		Amount		Amount		Amortization		Amount
Acquired identifiable intangibles:
Customer relationships	1-10	$	9,407	$	(6,202)	$	3,205	$	9,407	$	(6,041)	$	3,366
Developed technology	4-9		33,635		(17,848)		15,787		33,635		(17,250)		16,385
Tradename and trademarks	2-10		1,598		(839)		759		1,598		(812)		786
Patent	7-10		1,800		(1,650)		150		1,800		(1,640)		160
Noncompetition agreements	3		848		(377)		471		848		(306)		542
Total		$	47,288	$	(26,916)	$	20,372	$	47,288	$	(26,049)	$	21,239

The weighted average amortization period for acquired identifiable intangible assets was 6.6 years as of March 31, 2022. The following table summarizes intangible assets amortization expense in the Condensed Consolidated Statements of Comprehensive Loss (in thousands):

	Three Months Ended March 31,
	2022		2021
Amortization of acquired technology included under Costs of Revenues	$	553	$	535
Amortization of acquired intangible assets presented separately under Costs and Expenses		314		314
Total amortization of acquired intangible assets	$	867	$	849

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

Year Ending December 31,	Amount
2022 (remaining nine months)	$	2,601
2023		3,444
2024		3,046
2025		2,882
2026		2,712
2027 and thereafter		5,687
Total future amortization expense	$	20,372

There were no impairment charges for goodwill and intangible assets during the three months ended March 31, 2022 or 2021.

5. LEASES

The Company leases administrative and sales offices and certain equipment under non-cancellable 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 dates through 2028. The Company had no leases that were classified as a financing lease as of March 31, 2022, and December 31, 2021.

In the first quarter of 2022, the Company early terminated an office lease contract. The termination of this lease reduces the Company’s operating lease right-of-use assets and lease liabilities by approximately $0.5 million and $0.6 million, respectively. The gain from the lease termination of approximately $0.1 million was recorded under selling, general and administrative expense in the Condensed Consolidated Statement of Comprehensive Loss for the three months ended March 31, 2022.

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Lease expense was comprised of the following (in thousands):

	Three Months Ended March 31,
	2022		2021
Operating lease expense (1)	$	345	$	485
Short-term lease and variable lease expense (2)		283		174
Total lease expense	$	628	$	659

(1) Net of gain recognized upon lease termination of $0.1 million in three month ended March 31, 2022.

(2) Leases with an initial term of 12 months or less are not recorded on the Condensed Consolidated Balance Sheets, and the Company recognizes lease expense for these leases on a straight-line basis over the lease term. Variable lease expense for the periods presented primarily included common area maintenance charges.

Supplemental balance sheets information related to operating leases was as follows:

	March 31,			December 31,
	2022			2021
Weighted average remaining lease term under operating ROU leases (in years)		6.0			5.7
Weighted average discount rate for operating lease liabilities		5.25	%		5.25	%

Maturities of operating lease liabilities as of March 31, 2022, were as follows (in thousands):

Year Ending December 31,	Amount (1)
2022 (remaining nine months)	$	960
2023		1,137
2024		1,070
2025		1,086
2026		1,053
2027 and thereafter		1,650
Total future minimum lease payments	$	6,956
Less: Interest (2)		(990)
Present value of future minimum lease payments under operating lease liabilities (3)	$	5,966

(1) As of March 31, 2022, the total operating lease liability includes approximately $1.1 million related to an option to extend a lease term that is reasonably certain to be exercised.

(2) Calculated using incremental borrowing interest rate for each lease.

(3) Includes the current portion of operating lease liabilities of $1.2 million as of March 31, 2022.

6. STOCKHOLDERS’ EQUITY

Stock Repurchase Program

On June 4, 2020, the Company’s Board of Directors adopted a stock repurchase program (the “2020 Program”) to repurchase up to $25.0 million of the Company’s common stock both on the open market and in privately negotiated transactions, including through Rule 10b5-1 plans, over the next two years. During the three months ended March 31, 2022, 218,858 shares were repurchased under the 2020 Program at an average price of $26.40 per share for an aggregate total price of $5.8 million. During the three months ended March 31, 2021, approximately 251,000 shares were repurchased under the 2020 Program at an average price of $18.01 per share for an aggregate total price of $4.5 million. Through March 31, 2022, approximately 470,000 shares had been repurchased at an average price of $21.91 per share, for a total price of $10.3 million under the 2020 Program.

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On April 11, 2022, the Board of Directors terminated that 2020 Program, and adopted a new program (the “2022 Program”) to repurchase up to $35.0 million of the Company’s common stock both on the open market and in privately negotiated transactions, from time to time, over the next two years.

7. EMPLOYEE BENEFIT PLANS

On March 31, 2022, the Company had the following stock-based compensation plans:

Employee Stock Purchase Plan

In July 2001, the Company’s stockholders initially approved the 2001 Employee Stock Purchase Plan, which was subsequently amended and restated in 2010 (as amended, the “2010 Purchase Plan”) to extend the term of the plan through May 17, 2020. Under the 2010 Purchase Plan, eligible employees could contribute up to 10% of their compensation, as defined in the 2010 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 2010 Purchase Plan provided for twenty-four-month offering periods with four six-month purchase periods in each offering period. The 2010 Purchase Plan expired on May 17, 2020. Existing offering periods under the 2010 Plan continued through the applicable expiration date and the final offering period expired on January 31, 2022. On June 15, 2021, the Company’s stockholders approved the 2021 Employee Stock Purchase Plan, which has a ten-year term (the “2021 Purchase Plan”). The terms of 2021 Purchase Plan are substantially similar to those of the 2010 Purchase Plan. A twenty-four-month offering period under the 2021 Purchase Plan commenced on August 1, 2021.

The Company estimated the fair value of purchase rights granted under the 2010 and the 2021 Purchase Plans 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:

	2021 Purchase Plan			2010 Purchase Plan
	Three Months Ended March 31,			Three Months Ended March 31,
	2022			2021
Expected life (in years)		1.25			1.25
Volatility		48.90	%		34.25	%
Risk-free interest rate		0.86	%		1.43	%
Expected dividend		—			—
Weighted average fair value of purchase rights granted during the period	$	10.76		$	4.83

During the three months ended March 31, 2022, a total of approximately 95,243 shares were issued at a weighted-average purchase price of $15.77 per share. During the three months ended March 31, 2021, a total of approximately 99,674 shares were issued at a weighted-average purchase price of $9.24 per share. As of March 31, 2022, unrecognized compensation cost related to the 2021 Purchase Plan was $1.9 million. These costs are expected to be recognized over a weighted average period of 1.4 years.

Stock Incentive Plans

On November 16, 2011, the Company’s stockholders initially approved the 2011 Stock Incentive Plan, which has been amended and restated and approved by the Company’s stockholders a number of times since then (as amended, the “2011 Plan”). Under the 2011 Plan, the Company may award stock options, stock appreciation rights (“SARs”), 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 11,550,000 shares, plus up to 3,500,000 shares previously issued under the 2001 Stock Plan adopted by the Company in 2001, which expired in 2011 (the “2001 Plan”) that are either (i) forfeited or (ii) repurchased by the Company or are 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 SARs, the aggregate number of shares reserved under the 2011 Plan will be decreased at a rate of 1.33

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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 26, 2022, the Company’s Board of Directors amended the 2011 Plan, subject to stockholder approval, to increase the number of shares reserved for awards under it to a total of 12,800,000 shares, which is an increase of an additional 1,250,000 shares.

As of March 31, 2022, 12.1 million shares of common stock were reserved to cover stock-based awards under the 2011 Plan, of which 3.2 million shares were available for future grant. The number of shares reserved and available under the 2011 Plan includes 0.5 million shares that were subject to awards previously made under the 2001 Plan and were forfeited, expired or repurchased by the Company after the adoption of the 2011 Plan through March 31, 2022. As of March 31, 2022, there were no outstanding awards that had been granted outside of the 2011 or 2001 Plans (collectively, the “Stock Plans”).

The Company estimated the fair value of share-based awards granted under the 2011 Stock Plan during the period using the Black-Scholes-Merton option-pricing model. There were no stock options granted during the three months ended March 31, 2022 and 2021.

Stock-Based Compensation

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

	Three Months Ended March 31,
	2022		2021
Costs of revenues	$	728	$	652
Research and development		3,168		1,588
Selling, general and administrative		1,657		1,129
Stock-based compensation expenses	$	5,553	$	3,369

Additional information with respect to options under the Stock Plans during the three months ended March 31, 2022, is as follows:

	Outstanding Options
				Weighted
		Weighted		Average
		Average		Remaining	Aggregate
	Number of	Exercise		Contractual	Intrinsic
	Options	Price		Term	Value
	(in thousands)	per Share		(Years)	(in thousands)
Outstanding, January 1, 2022	226	$	12.78
Granted	—		—
Exercised	(75)		9.06
Canceled	(3)		13.57
Expired	—		—
Outstanding, March 31, 2022	148	$	14.64	4.19	$	1,954
Vested and expected to vest, March 31, 2022	146	$	14.63	4.15	$	1,936
Exercisable, March 31, 2022	121	$	14.54	3.45	$	1,612

The aggregate intrinsic value in the table above represents the total intrinsic value based on the Company’s closing stock price of $27.87 per share as of March 31, 2022. The total intrinsic value of options exercised was $1.3 million during the three months ended March 31, 2022.

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As of March 31, 2022, there was $0.1 million of total unrecognized compensation cost, net of forfeiture, related to unvested stock options, which is expected to be recognized over a weighted average period of 1.5 years. The total fair value of shares vested was immaterial during the three months ended March 31, 2022.

Nonvested restricted stock unit activity during the three months ended March 31, 2022, was as follows:

		Weighted
		Average Grant
	Shares	Date Fair Value
	(in thousands)	Per Share
Nonvested, January 1, 2022	1,872	$	18.24
Granted	275	$	27.90
Vested	(344)	$	19.73
Forfeited	(30)	$	18.43
Nonvested, March 31, 2022	1,773	$	19.45

As of March 31, 2022, there was $27.2 million of total unrecognized compensation cost related to restricted stock units. That cost is expected to be recognized over a weighted average period of 2.4 years. Restricted stock units do not have rights to dividends prior to vesting.

8. INCOME TAXES

Income tax expense increased $0.2 million for the three months ended March 31, 2022, to a $1.2 million income tax expense as compared to an income tax expense of $1.0 million for the three months ended March 31, 2021. The Company’s effective tax rate expense was (40%) and (14%) for the three months ended March 31, 2022 and 2021, respectively. The Company’s effective tax rate expense increased in the three months ended March 31, 2022, as compared to the same period in 2021, primarily due to increases in foreign withholding taxes and changes in the geographic mix of worldwide income, which is subject to taxation at different statutory tax rates.

The Company’s total amount of unrecognized tax benefits, excluding interest and penalties, as of March 31, 2022, was $15.0 million, of which $2.0 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, 2021, was $14.7 million, of which $1.9 million, if recognized, would affect the Company’s effective tax rate. As of March 31, 2022, the Company has recorded unrecognized tax benefits of $2.6 million, including interest and penalties of $0.7 million, as long-term taxes payable in its Condensed Consolidated Balance Sheet. The remaining $13.1 million has been recorded net of the Company’s DTAs, which is subject to a full valuation allowance.

The valuation allowance was approximately $51.6 million as of March 31, 2022 and December 31, 2021, which was related to U.S. net federal and state DTAs. The worldwide net deferred tax assets balance as of March 31, 2022 and December 31, 2021 were not significant.

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. For U.S. federal and California income tax purposes, the statute of limitations currently remains open for the tax years ending 2018 to present and 2017 to present, respectively. In addition, due to NOL carryback claims, the tax years 2013 through 2015 may be subject to federal examination and all of the net operating loss and research and development credit carryforwards that may be utilized in future years may be subject to federal and state examination. The Company is not subject to income tax examinations in any other of its major foreign subsidiaries’ jurisdictions.

9. NET LOSS PER SHARE

Basic net loss per share is computed by dividing net loss by weighted average number of common shares outstanding for the period (excluding outstanding stock options and shares subject to repurchase). Diluted net loss per share is computed using

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

	Three Months Ended March 31,
	2022		2021
Numerator:
Net loss	$	(4,150)	$	(7,597)
Denominator:
Basic weighted-average shares outstanding		37,606		36,974
Effect of dilutive options and restricted stock units		—		—
Diluted weighted-average shares outstanding		37,606		36,974
Net loss per share, basic and diluted	$	(0.11)	$	(0.21)

For the three months ended March 31, 2022 and 2021, because the Company was in a loss position, basic net loss per share is the same as diluted net loss per share as the inclusion of the potential common shares would have been anti-dilutive.

The following table sets forth potential shares of common stock that were not included in the diluted net loss per share calculation above because to do so would be anti-dilutive for the periods indicated (in thousands):

	Three Months Ended March 31,
	2022	2021
Outstanding options	102	224
Nonvested restricted stock units	905	1,107
Employee Stock Purchase Plan	94	10
Total	1,101	1,341

10. CUSTOMER AND GEOGRAPHIC INFORMATION

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

The Company’s chief operating decision maker, the chief executive officer, reviews discrete financial information presented on a consolidated basis for purposes of regularly making operating decisions, allocation of resources, and assessing financial performance. Accordingly, the Company considers itself to be in one operating and reporting segment, specifically the provision of services for differentiated data and analytics solutions to the semiconductor and electronics industries.

The Company had revenues from individual customers that are approximately 10% or more of the Company’s consolidated total revenues as follows:

	Three Months Ended March 31,
Customer	2022		2021
A	*	%	13	%
D	33	%	*	%
E	*	%	11	%

* represents less than 10%

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Gross accounts receivable balances (including amounts that are unbilled) from individual customers that are approximately 10% or more of the Company’s gross accounts receivable balance as follows:

	March 31,		December 31,
Customer	2022		2021
C	*	%	15	%
D	43	%	29	%

* represents less than 10%

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

	Three Months Ended March 31,
	2022				2021
			Percentage				Percentage
	Revenues		of Revenues		Revenues		of Revenues
United States	$	17,491	52	%	$	8,556	35	%
China		4,120	12			1,739	7
Japan		2,607	8			3,578	15
Rest of the world		9,280	28			10,327	43
Total revenue	$	33,498	100	%	$	24,200	100	%

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

	March 31,		December 31,
	2022		2021
United States (1)	$	40,602	$	39,158
Rest of the world		721		1,545
Total long-lived assets, net	$	41,323	$	40,703

(1) Includes assets deployed at customer sites which could be outside the U.S.

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11. 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, 2022, and December 31, 2021, and the basis for those measurements (in thousands):

	Fair Value Measurements Using
			Quoted
			Prices in
			Active		Significant
			Markets for		Other
			Identical		Observable		Significant
	March 31,		Assets		Inputs		Unobservable
Assets	2022		(Level 1)		(Level 2)		Inputs (Level 3)
Cash equivalents
Money market mutual funds	$	19,017	$	19,017	$	—	$	—
Short-term investments (available-for-sale debt securities)
U.S. Government securities (1)		98,443		98,443		—		—
Total	$	117,460	$	117,460	$	—	$	—

	Fair Value Measurements Using
			Quoted
			Prices in
			Active		Significant
			Markets for		Other		Significant
			Identical		Observable		Unobservable
	December 31,		Assets		Inputs		Inputs
Assets	2021		(Level 1)		(Level 2)		(Level 3)
Cash equivalents
Money market mutual funds	$	12,474	$	12,474	$	—	$	—
Short-term investments (available-for-sale debt securities)
U.S. Government securities (1)		112,542		112,542		—		—
Total	$	125,016	$	125,016	$	—	$	—

(1) As of March 31, 2022, and December 31, 2021, the amortized cost of the Company’s investments in U.S Government Securities approximated their fair value due to their short-term maturities, and there have been no events or changes

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in circumstances that would have had a significant effect on the fair value of these securities in the periods presented. There was no material realized or unrealized gains or losses, either individually or in the aggregate.

12. COMMITMENTS AND CONTINGENCIES

Strategic Partnership with Advantest — See Note 3, Strategic Partnership Agreement with Advantest And Related Party Transactions, for the discussion about the Company’s commitments under the strategic partnership with Advantest.

Operating Leases — Refer to Note 5, Leases, for the discussion about the Company’s lease commitments. The Company entered into lease agreements with total future minimum lease payments of $0.7 million over the next three years that will commence subsequent to March 31, 2022.

Indemnifications — The Company generally provides a warranty to its customers that its software will perform substantially in accordance with documented specifications typically for a period of 90 days following initial delivery of its products. The Company also indemnifies certain customers from third-party claims of intellectual property infringement relating to the use of its products. Historically, costs related to these guarantees have not been significant. The Company is unable to estimate the maximum potential impact of these guarantees on its future results of operations.

Purchase Obligations — The Company has purchase obligations with certain suppliers for the purchase of goods and services entered in the ordinary course of business. As of March 31, 2022, total outstanding purchase obligations were $12.8 million, the majority of which is due within the next 12 months.

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

In addition, the Bylaws of the Company provide that the Company is required to indemnify its officers and directors even when indemnification would otherwise be discretionary, and the Company is required to advance expenses to its officers and directors as incurred in connection with proceedings against them for which they may be indemnified. The Company has entered into indemnification agreements with its officers and directors containing provisions that are in some respects broader than the specific indemnification provisions contained in the Delaware general corporation law. The indemnification agreements require the Company to indemnify its officers and directors against liabilities that may arise by reason of their status or service as officers and directors other than for liabilities arising from willful misconduct of a culpable nature, to advance their expenses incurred as a result of any proceeding against them as to which they could be indemnified, and to obtain directors’ and officers’ insurance if available on reasonable terms. The Company has obtained directors’ and officers’ liability insurance in amounts comparable to other companies of the Company’s size and in the Company’s industry. Since a maximum obligation of the Company is not explicitly stated in the Company’s Bylaws or in its indemnification agreements and will depend on the facts and circumstances that arise out of any future claims, the overall maximum amount of the obligations cannot be reasonably estimated.

Legal Proceedings — 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. As of March 31, 2022, except as disclosed below, the Company was not party to any material legal proceedings, thus no loss was probable and no amount was accrued.

On May 6, 2020, the Company initiated an arbitration proceeding with the Hong Kong International Arbitration Center against SMIC New Technology Research & Development (Shanghai) Corporation (“SMIC”) due to SMIC’s failure to pay fees due to PDF under a series of contracts. The Company seeks to recover the unpaid fees, a declaration requiring SMIC to pay fees under the contracts in the future, and costs associated with bringing the arbitration proceeding. SMIC denies liability and the arbitration is on-going.

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13. SUBSEQUENT EVENTS

Refer to Note 7, Employee Benefits Plans, for the discussion about the amendment to the 2011 Stock Incentive Plan.

Refer to Note 6, Stockholder’s Equity, for the discussion about the adoption of the 2022 Stock Repurchase Program.

On April 12, 2022, the Company repurchased approximately 715,000 shares of its common stock in a privately negotiated transaction for $16.7 million under the 2022 Stock Repurchase Program. The stock repurchase was made in a block trade in compliance with Rule 10b-18 under the Securities Exchange Act of 1934, as amended (the Exchange Act).

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

Forward-Looking Statements

The following discussion of our financial condition and results of operations contains forward-looking statements within the meaning of Section 27A of the Securities Act of 1933 and Section 21E of the Securities Exchange Act of 1934. All statements other than statements of historical fact may be forward-looking statements. In some cases, you can identify forward-looking statements by terminology such as “may,” “could,” “projected,” “should,” “expect,” “plan,” “anticipate,” “believe,” “estimate,” “predict,” “potential”, “target” or “continue,” the negative effect of terms like these or other similar expressions. These statements include, but are not limited to, statements concerning: expectations about the effectiveness of our business and technology strategies; expectations regarding global economic trends; the impact of inflation, expectations regarding recent and future acquisitions; current semiconductor industry trends; expectations of the success and market acceptance of our intellectual property and our solutions; the continuing impact of the coronavirus (COVID-19) on the semiconductor industry and our business and our ability to obtain additional financing if needed. These forward-looking statements are only predictions. Forward-looking statements are based on current expectations and projections about future events and are inherently subject to a variety of risks and uncertainties, many of which are beyond our control, which could cause actual results to differ materially from those anticipated or projected. All forward-looking statements included in this document are based on information available to us on the date of filing and we further caution investors that our business and financial performance are subject to substantial risks and uncertainties. We assume no obligation to update any such forward-looking statements. In evaluating these statements, you should specifically consider various factors, including the risk factors set forth in Item 1. “Business” and Item 7. “Management’s Discussion and Analysis of Financial Condition and Results of Operations” in our Annual Report on Form 10 K for the year ended December 31, 2021, filed with the Securities and Exchange Commission on March 1, 2022. All references to “we”, “us”, “our”, “PDF”, “PDF Solutions” or “the Company” refer to PDF Solutions, Inc.

Cimetrix, CV, DFI, Exensio, PDF Solutions, the PDF Solutions logo are trademarks or registered trademarks of PDF Solutions, Inc. or its subsidiaries.

Overview

We provide comprehensive data solutions designed to empower organizations across the semiconductor ecosystem to improve the yield and quality of their products and operational efficiency for increased profitability. Our offerings include proprietary software, professional services based on proven methodologies and using third-party cloud-hosting platforms for software-as-a-service (“SaaS”), electrical measurement hardware tools, and physical intellectual property (“IP”) for integrated circuit (“IC”) designs. We derive revenues from two sources, Analytics and Integrated Yield Ramp, by monetizing our offerings through contract fees for on-premise licenses, SaaS, and other professional services and a value-based, variable fee or royalty, which we call Gainshare, on some Characterization services engagements. Our products and services have been sold to integrated device manufacturers (“IDMs”), fabless semiconductor companies, foundries, equipment manufacturers, electronics manufacturing suppliers (“EMS”), original device manufacturers (“ODMs”), out-sourced semiconductor assembly and test (“OSATs”), and system houses. We are headquartered in Santa Clara, California and also operate worldwide with offices in Canada, China, France, Germany, Italy, Japan, Korea, and Taiwan.

Industry Trends

The COVID-19 pandemic has significantly affected how we and our customers operate our businesses. For example, most U.S. states and countries worldwide imposed in 2020, and may continue to impose from time-to-time for the foreseeable future, restrictions on the physical movement of people to limit the spread of COVID-19, including travel restrictions and stay-at-home orders. We continue to closely monitor the COVID-19 situation and expect to ask employees to return to working in offices according to local restrictions, in each case, with a focus on our employees’ safety. In addition, our personnel worldwide continue to be subject to various country-to-country travel restrictions, which limits the ability of some employees to travel to other offices or customer sites. We believe the lack of an ability to meet in person during most of 2021 and to some degree the first quarter of 2022 made it harder for us to sell complex or new technologies to some customers during these periods. Once we can again begin to meet with these customers in person, we believe we may improve traction with them. To date, we have been able to provide uninterrupted access to our products and services due to our globally distributed

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workforce, many of whom were working remotely prior to the pandemic, and our pre-existing infrastructure, which supports secure access to our internal systems. The total duration and full extent of the impact from the COVID-19 pandemic depends on future developments that cannot be accurately predicted at this time, such as the ultimate severity and transmission rate of the virus and variants, the extent and effectiveness of containment actions and vaccinations, and the impact of these and other factors on our employees, customers, partners, and suppliers. To date, one effect of the COVID-19 pandemic is a global shortage in semiconductors due primarily to supply chain disruptions and many companies, including in the automotive industry, have announced shortages in production. Although this shortage has not materially affected our business, this trend may affect our future business opportunities, particularly future Gainshare and Cimetrix run-time licenses, if our customers’ production volumes decrease.

Certain other trends may affect our Analytics revenue specifically. In particular, the confluence of Industry 4.0 (i.e. the fourth industrial revolution, or the automation and data exchange in manufacturing technologies and processes) and cloud computing (i.e. the on-demand availability of computing resources and data storage without direct active management by the user) is driving increased innovation in semiconductor and electronics manufacturing and analytics, as well as in the organization of IT networks and computing at semiconductor and electronics companies across the ecosystem. First, the ubiquity of wireless connectivity and sensor technology enables any manufacturing company to augment its factories and visualize its entire production line. In parallel, the cost per terabyte of data storage has continually decreased year to year. The combination of these two trends means that more data is collected and stored than ever before. Further, semiconductor companies are striving to analyze these very large data sets in real-time to make rapid decisions that measurably improve manufacturing efficiency and quality. In parallel, the traditional practice of on-site data storage, even for highly sensitive data, is changing. The ability to cost-effectively and securely store, analyze, and retrieve massive quantities of data from the cloud versus on-premise enables data to be utilized across a much broader population of users, frequently resulting in greater demands on analytics programs. The combination of these latter two trends means that cloud-based, analytic programs that effectively manage identity management, physical security, and data protection are increasingly in demand for insights and efficiencies across the organizations of these companies. We believe that all these trends will continue for the next few years, and the challenges involved in adopting Industry 4.0 and secure cloud computing will create opportunities for our combination of advanced analytics capabilities, proven and established supporting infrastructure, and professional services to configure our products to meet customers’ specialized needs.

Other trends may continue to affect our characterization services business and Integrated Yield Ramp revenue specifically. The logic foundry market at the leading-edge nodes, such as 10nm, 7nm, and smaller, underwent significant change over the past few years. The leading foundry continues to dominate market share as other foundries started later than originally forecast in some cases. This trend will likely continue to impact our characterization services business on these nodes. We expect most logic foundries to invest in derivatives of older process nodes, such as 28nm and 14nm, to extract additional value as many of their customers will not move to advanced nodes due to either technological barriers or restrictive economics. Foundries that participate at leading edge nodes are expected to continue to invest in new technologies such as memory, packaging, and multi-patterned and EUV lithography, as well as new innovations in process control and variability management. We expect China’s investment in semiconductors to continue. In order for these trends to provide opportunities for us to increase our business leveraging electrical characterization, Chinese semiconductors manufacturers will need to increase their production volumes on advanced technology nodes and continue to engage foreign suppliers, subject to compliance with changing U.S. export restrictions. As a result of these market developments, we have chosen to focus our resources and investments in products, services, and solutions for analytics.

There are other business trends that may affect our business opportunities generally. For instance, the demand for consumer electronics, communications devices, and high-performance computing 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 continue to fuel 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 power and cost per transistor. 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 these difficulties will continue to create a need for our products and services that address yield loss across the IC product life cycle. For further instance, the ongoing Russo-Ukrainian war is negatively impacting the global supply chain

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generally, e.g., reducing the production of millions of new cars and trucks, which indirectly impacts the global semiconductor market, and also affecting global energy markets and causing shortages and rising prices of semiconductors directly. Ukraine and Russia are both top suppliers of neon gas that is used in lasers and chip manufacturing, and Russia is a major producer of palladium, a rare metal used in computer components, sensors, and fuel cells. Limitations on the supply of these two elements can severely affect the global supply chain, which is already scarce in semiconductors. Russia also supplies much of the world’s premium nickel, which is used by electronics manufacturers to make batteries. If these trends continue or worsen, we may face a shortage of critical components for our own tools and our business may suffer if the business of our customers decreases. Rising prices of semiconductors may mean increased royalties to us and increased Integrated Yield Ramp revenue.

The U.S. government continues to expand and intensify export controls and sanctions, including the addition of many P.R.C. and Russian companies to the U.S. Export Administration Regulations (“EAR”) Entity List. These listings restrict supply to designees of items that are subject to the EAR. After an internal evaluation, we determined that a large percentage of our software products are not of U.S. origin and are, thus, not subject to the EAR. Our standard operations include development, distribution processes, software download sites, and professional service centers and processes located in various geographies around the world to better serve our customers. Some customers in the P.R.C., in particular, have nonetheless expressed concerns to us that continued action by the U.S. government could potentially interrupt their ability to make use of our products or services. The continuing tension between the U.S. and P.R.C. and/or Russian governments in trade and security matters or the perception of that tension could lead to disruptions or reductions in international trade, deter or prevent purchasing activity of customers, and negatively impact our China sales (with respect to U.S.-P.R.C. tensions) and financial results in general (with respect to global tensions).

Financial Highlights

Financial highlights for the three months ended March 31, 2022, are as follows:

● Total revenues were $33.5 million, an increase of $9.3 million, or 38%, compared to the three months ended March 31, 2021. Analytics revenue was $30.4 million, an increase of $11.0 million, or 57%, compared to the three months ended March 31, 2021. The increase in Analytics revenue was driven by increases in revenue from CV systems and DFI systems across multiple contracts and customers, and increases in revenues from Exensio and Cimetrix software licenses. Integrated Yield Ramp revenue decreased $1.7 million, or 36%, compared to the year-ago period primarily due to a decrease due to the end of Gainshare periods, partially offset by an increase in hours worked on fixed fees engagements.

● Costs of revenues increased $0.9 million, compared to the three months ended March 31, 2021, primarily due to increases in personnel-related costs, cloud-delivery costs, software royalty and licenses expense. These increases were partially offset by decreases in facilities and information technology-related costs including depreciation expenses.

● Net loss was $4.2 million, compared to $7.6 million for the three months ended March 31, 2021. The decrease in net loss was primarily attributable to an increase in total revenues, partially offset by increases in costs of revenues and operating expenses related primarily to our research and development, sales and marketing activities, and general and administrative expenses, all of which were primarily related to increases in personnel-related costs due to higher compensation and benefit costs, and stock-based compensation expense, facilities and information technology-related costs, legal expenses, cloud-services related costs and an increase in income tax expense.

● Cash, cash equivalents and short-term investments decreased $6.0 million to $134.2 million at March 31, 2022, from $140.2 million at December 31, 2021, primarily due to cash used to repurchase shares of common stock and payment for taxes related to net share settlement of equity awards, and purchase of property and equipment, partially offset by proceeds from the exercise of stock options, proceeds from purchases under our employee stock purchase plans and cash provided by operating activities.

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Critical Accounting Policies and Estimates

See Note 1, Basis of Presentation And Summary of Significant Accounting Policies, to our condensed consolidated financial statements in 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 condensed consolidated financial statements, and 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, 2021.

There were no material changes during the three months ended March 31, 2022, to the items that we disclosed as our critical accounting policies and estimates in Management’s Discussion and Analysis of Financial Condition and Results of Operations in our Annual Report on Form 10-K for the year ended December 31, 2021.

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 condensed consolidated financial statements, which have been prepared in conformity with accounting principles generally accepted in the United States of America. Our preparation of these condensed 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 base 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, valuation of long-lived assets including goodwill and intangible assets, 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: Analytics and Integrated Yield Ramp.

Analytics Revenue

Analytics revenue is derived from the following primary offerings: licenses and services for standalone Software (which consists primarily of Exensio and Cimetrix products), SaaS (which consists primarily of Exensio products), and DFI and CV systems (including Characterization services) that do not include performance incentives based on customers’ yield achievement.

Revenue from standalone software is recognized depending on whether the license is perpetual or time-based. Perpetual (one-time charge) license software is recognized at the time of the inception of the arrangement when control transfers to the customers, if the software license is distinct from the services offered by us. Revenue from post-contract support is recognized over the contract term on a straight-line basis, because we are providing (i) support and (ii) unspecified software updates on a when-and-if available basis over the contract term. Revenue from time-based-licensed software is allocated to each performance obligation and is recognized either at a point in time or over time as follows. The license component is recognized at the time when control transfers to customers, with the post-contract support component recognized ratably over the committed term of the contract. For contracts with any combination of licenses, support, and other services, distinct performance obligations are accounted for separately. For contracts with multiple performance obligations, we allocate the transaction price of the contract to each performance obligation on a relative basis using the standalone selling price (“SSP”) attributed to each performance obligation.

Revenue from SaaS arrangements, which allow for the use of a cloud-based software product or service over a contractually determined period of time without taking possession of software, is accounted for as subscriptions and is recognized as revenue ratably, on a straight-line basis, over the subscription period beginning on the date the service is first made available to customers.

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Revenue from DFI systems and CV systems (including Characterization services) that do not include performance incentives based on customers’ yield achievement is recognized primarily as services are performed. Where there are distinct performance obligations, we allocate revenue to all deliverables based on their SSPs. For these contracts with multiple performance obligations, we allocate the transaction price of the contract to each performance obligation on a relative basis using SSP attributed to each performance obligation. Where there are not discrete performance obligations, historically, revenue is primarily recognized as services are performed using a percentage of completion method based on costs or labor-hours inputs, whichever is the most appropriate measure of the progress towards completion of the contract. The estimation of percentage of completion method is complex and subject to many variables that require significant judgment.

Integrated Yield Ramp Revenue

Integrated Yield Ramp revenue is derived from our yield ramp engagements that include Gainshare or other performance incentives based on customers’ yield achievement.

Revenue under these project–based contracts, which are delivered over a specific period of time typically for a fixed fee component paid on a set schedule, is recognized as services are performed using a percentage of completion method based on costs or labor-inputs, whichever is the most appropriate measure of the progress towards completion of the contract. Where there are distinct performance obligations, we allocate revenue to all deliverables based on their SSPs and allocate the transaction price of the contract to each performance obligation on a relative basis using SSP. Similar to the services provided in connection with DFI systems and CV systems that are contributing to Analytics revenue, due to the nature of the work performed in these arrangements, the estimation of percentage of completion method is complex and subject to many variables that require significant judgment.

The Gainshare royalty contained in yield ramp contracts is a variable fee related to continued usage of our IP after the fixed-fee service period ends, based on the customers’ yield achievement. Revenue derived from Gainshare is contingent upon our customers reaching certain defined production yield levels. Gainshare royalty periods are generally subsequent to the delivery of all contractual services and performance obligations. We record Gainshare as a usage-based royalty derived from customers’ usage of intellectual property and record it in the same period in which the usage occurs.

Income Taxes

We are required to assess whether it is “more-likely-than-not” that we will realize our deferred tax assets. If we believe that they are not likely to be fully realizable before the expiration dates applicable to such assets, then to the extent we believe that recovery is not likely, we must establish a valuation allowance. Based on all available evidence, both positive and negative, we determined a full valuation allowance was still appropriate for our U.S. federal and state net deferred tax assets (“DTAs”), primarily driven by a cumulative loss incurred over the 12-quarter period ended March 31, 2022, and the likelihood that we may not utilize tax attributes before they expire. The valuation allowance was approximately $51.6 million as of March 31, 2022, and December 31, 2021. We will continue to evaluate the need for a valuation allowance and may change our conclusion in a future period based on changes in facts (e.g., 12-quarter cumulative profit, significant new revenue, etc.). If we conclude that we are more likely than not to utilize some or all of our U.S. DTAs, we will release some or all of our valuation allowance and our tax provision will decrease in the period in which we make such determination.

We evaluate our DTAs for realizability considering both positive and negative evidence, including our historical financial performance, projections of future taxable income, future reversals of existing taxable temporary differences, tax planning strategies and any carryback availability. In evaluating the need for a valuation allowance, we estimate future taxable income based on management approved business plans. This process involves significant management judgment about assumptions that are subject to change from period to period based on changes in tax laws or variances between future projected operating performance and actual results. Changes in the net DTAs, less offsetting valuation allowance, in a period are recorded through the income tax provision and could have a material impact on the Condensed Consolidated Statements of Comprehensive Loss.

Our income tax calculations are based on application of applicable 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

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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 Condensed Consolidated Statements of Comprehensive Loss. At March 31, 2022, no deferred taxes have been provided on undistributed earnings from our international subsidiaries. We intend to reinvest the earnings of our non-U.S. subsidiaries in those operations indefinitely. As such, we have not provided for any foreign withholding taxes on the earnings of foreign subsidiaries as of March 31, 2022. The earnings of our foreign subsidiaries are taxable in the U.S. in the year earned under the Global Intangible Low-Taxed Income rules implemented under 2017 Tax Cuts and Jobs Act.

Valuation of Long-lived Assets including Goodwill and Intangible Assets

We record goodwill when the purchase consideration of an acquisition exceeds the fair value of the net tangible and identified intangible assets as of the date of acquisition. We have one operating segment and one operating unit. We perform an annual impairment assessment of goodwill during the fourth quarter of each calendar year or more frequently, if required to determine if any events or circumstances exist, such as an adverse change in business climate or a decline in the overall industry demand, that would indicate that it would more likely than not reduce the fair value of a reporting unit below its carrying amount, including goodwill. If events or circumstances do not indicate that the fair value of a reporting unit is below its carrying amount, then goodwill is not considered to be impaired and no further testing is required. If the carrying amount exceeds its fair value, an impairment loss would be recognized equal to the amount of excess, limited to the amount of total goodwill. There was no impairment of goodwill for the three months ended March 31, 2022.

Our long-lived assets, excluding goodwill, consist of property, equipment, and intangible assets. We periodically review our long-lived assets for impairment. For assets to be held and used, we initiate our review whenever events or changes in circumstances indicate that the carrying amount of a long-lived asset group may not be recoverable. Recoverability of an asset group is measured by comparison of its carrying amount to the expected future undiscounted cash flows that the asset group is expected to generate. If it is determined that an asset group is not recoverable, an impairment loss is recorded in the amount by which the carrying amount of the asset group exceeds its fair value. There was no impairment of long-lived assets for the three months ended March 31, 2022.

Recent Accounting Pronouncements and Accounting Changes

See Note 1, Basis of Presentation and Summary of Significant Accounting Policies, to our condensed consolidated financial statements 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 condensed consolidated financial statements.

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Results of Operations

Discussion of Financial Data for the Three Months ended March 31, 2022

Revenues, Costs of Revenues, and Gross Margin

	Three Months Ended
	March 31,						Change
(Dollars in thousands)	2022			2021			$		%
Revenues:
Analytics	$	30,426		$	19,393		$	11,033	57	%
Integrated Yield Ramp		3,072			4,807			(1,735)	(36)	%
Total revenues		33,498			24,200			9,298	38	%
Costs of revenues		11,529			10,663			866	8	%
Gross profit	$	21,969		$	13,537		$	8,432	62	%
Gross margin		66	%		56	%
Analytics revenue as a percentage of total revenues		91	%		80	%
Integrated Yield Ramp revenue as a percentage of total revenues		9	%		20	%

Analytics Revenue

Analytics revenue increased $11.0 million for the three months ended March 31, 2022, compared to the three months ended March 31, 2021. The increase in Analytics revenue was primarily driven by increases in revenue from CV systems and DFI systems across multiple contracts and customer, and increases in revenues from Exensio and Cimetrix software licenses.

Integrated Yield Ramp Revenue

Integrated Yield Ramp revenue decreased $1.7 million for the three months ended March 31, 2022, compared to the prior year period, due to a decrease due to the end of Gainshare periods, partially offset by an increase in hours worked on fixed fees engagements. Our Integrated Yield Ramp revenue may continue to fluctuate from period to period primarily due to the contribution of Gainshare royalty, which 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 contracts containing Gainshare.

Our Analytics and Integrated Yield Ramp revenues may fluctuate in the future and are dependent on a number of factors, including the semiconductor industry’s continued acceptance of our products, services and solutions, the timing of purchases by existing and new customers, cancellations by existing customers, and our ability to attract new customers and penetrate new markets, 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, including due to adverse changes in their own business.

Costs of Revenues

Costs of revenues consist primarily of costs incurred to provide and support our services, costs recognized in connection with licensing our software, and amortization of acquired technology. Service costs include material, employee compensation and related benefits including stock-based compensation expense, subcontractor costs, overhead costs, travel and allocated facilities-related costs. Software license costs consist of costs associated with cloud-delivery related expenses and licensing third-party software used by us in providing services to our customers in solution engagements or sold in conjunction with our software products.

The increase in costs of revenues of $0.9 million for the three months ended March 31, 2022, compared to the three months ended March 31, 2021, was primarily due to (i) a $0.6 million increase in cloud-delivery costs, software royalty, and

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licenses expense, and (ii) a $0.4 million increase in personnel-related costs. These were partially offset by a $0.3 million decrease in facilities and information technology-related costs including depreciation expense.

Gross Margin

Gross margin increased 10% for the three months ended March 31, 2022, to 66%, compared to 56% for the year-ago period. The higher gross margin during three months ended March 31, 2022 was primarily due to higher total revenue and decreases in certain costs of revenues, as discussed above, which decreased the costs of revenues as a percentage of total revenues, when compared to the year-ago period.

Operating Expenses:

Research and Development

	Three Months Ended
	March 31,						Change
(Dollars in thousands)	2022			2021			$		%
Research and development	$	14,089		$	10,841		$	3,248	30	%
As a percentage of total revenues		42	%		45	%

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

Research and development expenses increased for the three months ended March 31, 2022, compared to the year-ago period, primarily due to (i) a $2.7 million increase in personnel-related costs due to higher compensation and benefit costs, and stock-based compensation expense, (ii) a $0.3 million increase in subcontractor expenses primarily related to our DFI systems and Exensio and Cimetrix software, and (iii) a $0.3 million increase in facilities and information technology-related costs.

We anticipate our expenses in research and development will fluctuate in absolute dollars from period to period as a result of the size and the timing of product development projects.

Selling, General, and Administrative

	Three Months Ended
	March 31,						Change
(Dollars in thousands)	2022			2021			$		%
Selling, general and administrative	$	10,839		$	9,464		$	1,375	15	%
As a percentage of total revenues		32	%		39	%

Selling, general, and administrative expenses consist primarily of compensation, benefits and stock-based compensation expense for sales, marketing and general and administrative personnel, legal and accounting services, marketing communications expenses, third-party cloud-services related costs, travel and facilities cost allocations.

Selling, general, and administrative expenses increased for the three months ended March 31, 2022, compared to the year-ago period, primarily due to (i) a $1.1 million increase in personnel-related costs due to higher compensation and benefit costs and stock-based compensation expense, (ii) a $0.2 million increase in general legal expenses, (iii) a $0.2 million increase in legal fees related to the arbitration proceeding over a disputed customer contract, and (iv) a $0.2 million increase in cloud-services related costs. These were partially offset by a (i) $0.4 million decrease in subcontractor expenses and (ii) a $0.1 million decrease in accounting related fees.

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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.

Amortization of Other Acquired Intangible Assets

	Three Months Ended
	March 31,				Change
(Dollars in thousands)	2022		2021		$		%
Amortization of acquired intangible assets	$	314	$	314	$	—	—	%

Amortization of other acquired intangible assets consists of amortization of intangibles acquired as a result of certain business combinations.

Interest and Other Expense (Income), Net

	Three Months Ended
	March 31,				Change
(Dollars in thousands)	2022		2021		$		%
Interest and other expense (income), net	$	(310)	$	(441)	$	131	(30)	%

Interest and other expense (income), net, primarily consists of interest income, and foreign currency transaction exchange gains and losses.

Interest and other expense (income), net decreased for the three months ended March 31, 2022, compared to the year-ago period, primarily due to a lower foreign currency exchange gain resulting from a net favorable fluctuation in foreign exchange rates.

Income Tax Expense

	Three Months Ended
	March 31,				Change
(Dollars in thousands)	2022		2021		$		%
Income tax expense	$	1,187	$	956	$	231	24	%

Income tax expense increased for the three months ended March 31, 2022, compared to the same year-ago period, primarily due to increases in foreign withholding taxes and changes in the geographic mix of worldwide income, which is subject to taxation at different statutory tax rates.

Any significant change in our future effective tax rates could adversely impact our consolidated financial position, results of operations and cash flows. Our future tax rates may be adversely affected by a number of factors including increase in expenses not deductible for tax purposes, tax legislations in the United States and in foreign countries where we are subject to tax jurisdictions, the geographic composition of our pre-tax income, the amount of our pre-tax income as business activities fluctuate, our ability to use tax attributes such as research and development tax credits and net operation losses, the tax effects of employee stock activity, audit examinations with adverse outcomes, changes in general accepted accounting principles and the effectiveness of our tax planning strategies.

Liquidity and Capital Resources

As of March 31, 2022, our working capital, defined as total current assets less total current liabilities, was $138.3 million, compared to $144.7 million as of December 31, 2021. Total cash and cash equivalents, and short-term investments were $134.2 million as of March 31, 2022, compared to cash and cash equivalents of $140.2 million as of December 31, 2021. As of March 31, 2022, and December 31, 2021, cash and cash equivalents held by our foreign subsidiaries were $5.6 million and

33

$5.3 million, respectively. We believe that our existing cash resources and anticipated funds from operations will satisfy our cash requirements to fund our operating activities, capital expenditures, other obligations for at least the next twelve months.

There has been no significant impact in respect to Liquidity and Capital Resources from the global COVID-19 pandemic.   For risk discussion about the continuing impact of global COVID-19 pandemic on our operations or demand for our products, refer to Item 1A, Risk Factors on Part I of our Annual Report for the year ended December 31, 2021, filed with the SEC on March 1, 2022.

Repurchase of Company’s Common Stock

On June 4, 2020, the Company’s Board of Directors adopted a stock repurchase program (the “2020 Program”) to repurchase up to $25.0 million of the Company’s common stock both on the open market and in privately negotiated transactions, including through Rule 10b5-1 plans, over the next two years. During the three months ended March 31, 2022, 218,858 shares were repurchased at an average price of $26.40 per share, for a total price of $5.8 million under the 2020 Program. Through April 10, 2022, approximately 470,000 shares had been repurchased at an average price of $21.91 per share, for a total price of $10.3 million under the 2020 Program. On April 11, 2022, the Board of Directors terminated that 2020 stock repurchase program, and adopted a new program (the “2022 Program”) to repurchase up to $35.0 million of the Company’s common stock both on the open market and in privately negotiated transactions, from time to time, over the next two years.

On April 12, 2022, the Company repurchased approximately 715,000 shares of its common stock in a privately negotiated transaction for $16.7 million under the 2022 Stock Repurchase Program. The stock repurchase was made in a block trade in compliance with Rule 10b-18 under the Securities Exchange Act of 1934, as amended (the Exchange Act).

Cash Flow Data

The following table summarizes our cash flows for the periods presented:

	Three Months Ended March 31,
	2022		2021		$ Change
(In thousands)
Net cash flows provided by (used in):
Operating activities	$	2,996	$	(8,325)	$	11,321
Investing activities		12,276		56,417		(44,141)
Financing activities		(6,990)		(4,497)		(2,493)
Effect of exchange rate changes on cash and cash equivalents		(167)		(104)		(63)
Net increase in cash, cash equivalents, and restricted cash	$	8,115	$	43,491	$	(35,376)

Net Cash Flows Provided by Operating Activities

Cash flows provided by operating activities during the three months ended March 31, 2022, consisted of net loss, adjusted for certain non-cash items which primarily consisted of depreciation and amortization, share-based compensation expense, amortization of acquired intangible expense, amortization of costs capitalized to obtain revenue contracts and net change in operating assets and liabilities. The $11.3 million increase in cash flows from operating activities for the three months ended March 31, 2022, compared to the year-ago period, was driven primarily by a $6.0 million increase in net change from operating assets and liabilities, a $3.4 million decrease in net loss, and a $1.9 million increase in non-cash adjustments to net

34

loss, which was primarily due to an increase in stock-based compensation expense of $2.2 million, partially offset by a decrease in depreciation and amortization of $0.3 million.

The major contributors to the net change in operating assets and liabilities for the three months ended March 31, 2022, were as follows:

● Accounts receivable decreased by $2.3 million, primarily due to the collections from customers partially offset by an increase in sales and higher contractual invoicing activity during the first quarter of 2022;

● Prepaid expense and other current assets increased by $1.0 million, primarily due to the increase in deferred commission and prepaid expenses related to third party software licenses;

● Accounts payable decreased by $2.1 million primarily due to the timing of payments of vendor invoices; and

● Accrued compensation and related benefits decreased by $0.9 million primarily due to the timing of payments of accrued bonuses, accrued sales commissions and accrued payroll taxes, and exercised of purchase rights under employee stock purchase plans, partially offset by an increased in accrued vacation.

Net Cash Flows Provided by Investing Activities

Cash provided by investing activities decreased by $44.1 million for the three months ended March 31, 2022, compared to the year-ago period.

For the three months ended March 31, 2022, cash provided by investing activities primarily related to proceeds from maturities and sales of short-term investments of $32.0 million and $3.0 million, respectively, partially offset by purchases of short-term investments of $21.0 million and property and equipment of $1.8 million primarily related to our DFI systems.

For the three months ended March 31, 2021, cash provided by investing activities primarily related to proceeds from maturities of short-term investments of $68.0 million, offset by purchases of short-term investments of $11.0 million and property and equipment of $0.6 million.

Net Cash Flows Used in Financing Activities

Net cash used in financing activities increased by $2.5 million for the three months ended March 31, 2022 compared to the year-ago period. 

For the three months ended March 31, 2022, net cash used in financing activities primarily consisted of $5.8 million for the repurchase of shares of our common stock and $3.4 million in cash payments for taxes related to net share settlement of equity awards, partially offset by $2.2 million of proceeds from our employee stock purchase plans and exercise of stock options.

For the three months ended March 31, 2021, net cash used in financing activities primarily consisted of $4.5 million for the repurchase of shares of our common stock and $1.5 million in cash payments for taxes related to net share settlement of equity awards, partially offset by $1.5 million of proceeds from our 2010 employee stock purchase plan and exercise of stock options.

Related Party Transactions

Refer to Note 3, Strategic Partnership Agreement with Advantest and Related Party Transactions, to our condensed consolidated financial statements in this Quarterly Report on Form 10-Q, for a discussion on related party transactions between the Company and Advantest.

35

Off-Balance Sheet Agreements

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

Item 3. Quantitative and Qualitative Disclosures about Market Risk

We are exposed to three primary types of market risks: credit risk and counterparty risk, foreign currency exchange rate risk and interest rate 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, 2022, we had cash and cash equivalents and short-term investments of $134.2 million. Cash and cash equivalents consisted of cash and highly liquid money market instruments and short-term investments consisted of U.S. Government securities. 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, 2022, 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.

At March 31, 2022 and periodically throughout the year, we have maintained cash balances in various operating accounts in excess of federally insured limits. We limit the amount of credit exposure to any financial institution by evaluating the creditworthiness of the financial institutions with which we invest and investing through more than one financial institution.

Foreign Currency and Exchange Risk.  Certain of our receivables and payables for our international offices are denominated in the local currency, including the Euro, Yen and RMB. Therefore, a portion of our revenues and operating expenditures are subject to foreign currency risks. From time to time, we enter into foreign currency forward contracts to reduce the exposure to foreign currency exchange rate fluctuations on certain foreign currency denominated monetary assets and liabilities. We do not use foreign currency forward contracts for speculative or trading purposes. We record these forward contracts at fair value. The counterparty to these foreign currency forward contracts is a financial institution that we believe is creditworthy, and therefore, we believe the credit risk of counterparty non-performance is not significant. As of March 31, 2022, we had no outstanding forward contracts.

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, 2022, in connection with the filing of this Quarterly Report on Form 10-Q. Based on that evaluation as of March 31, 2022, our principal executive officer and principal financial and accounting officer concluded that our disclosure controls and procedures were effective to ensure that information we are required to disclose in reports that we file or submit under the Exchange Act is recorded, processed, summarized and reported within the time periods specified in rules and forms of the SEC and accumulated and communicated to our management as appropriate to allow timely decisions regarding required disclosure.

Changes in Internal Control over Financial Reporting

There were no changes in the Company’s internal control over financial reporting during the three months ended March 31, 2022, that have materially affected, or are reasonably likely to materially affect, the Company’s internal control over financial reporting.

36

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. As of March 31, 2022, except as disclosed below, we were not a party to any material legal proceedings where a loss was probable, and thus no amount was accrued.

On May 6, 2020, the Company initiated an arbitration proceeding with the Hong Kong International Arbitration Center against SMIC New Technology Research & Development (Shanghai) Corporation (“SMIC”) due to SMIC’s failure to pay fees due to PDF under a series of contracts. The Company seeks to recover the unpaid fees, a declaration requiring SMIC to pay fees under the contracts in the future, and costs associated with bringing the arbitration proceeding. SMIC denies liability and the arbitration is on-going.

Item 1A. Risk Factors

As of the date of this Quarterly Report on Form 10-Q, there have been no material changes from the risk factors disclosed in our Annual Report on Form 10-K for the year ended December 31, 2021, filed with the Securities and Exchange Commission on March 1, 2022. Any of such factors could result in a significant or material adverse effect on our result of operations or financial conditions. Additional risk factors not presently known to us or that we currently deem immaterial may also impair our business or results of operations. We may disclose changes to such factors or disclose additional factors from time to time in our future filings with the SEC.

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

On June 4, 2020, the Company’s Board of Directors adopted a stock repurchase program (the “2020 Program”) to repurchase up to $25.0 million of the Company’s common stock both on the open market and in privately negotiated transactions, including through Rule 10b5-1 plans, over the next two years.

The table below sets forth the information with respect to purchases made under the 2020 Program by or on behalf of the Company or any “affiliated purchaser” (as the term is defined in Rule 10b-18(a)(3) under the Exchange Act) of our common stock during the three months ended March 31, 2022. Under the 2020 Program, $14.7 million of common stock remained available for future repurchases as of March 31, 2022.

					Approximate
				Total Number	Dollar
				of Shares	Value of
				Purchased	Shares that
	Total			as Part of	May Yet Be
	Number of			Publicly	Purchased
	Shares	Average		Announced	Under
	Purchased	Price Paid		Programs	Programs
Period	(in thousands)	Per Share		(in thousands)	(in thousands)
January 1, 2022 through January 31, 2022	—	$	—	—	$	20,477
February 1, 2022 through February 28, 2022	60	$	26.48	60	$	18,885
March 1, 2022 through March 31, 2022	159	$	26.37	159	$	14,700
Total	219	$	26.40	219

On April 11, 2022, the Board of Directors terminated that 2020 Program, and adopted a new program (the “2022 Program”) to repurchase up to $35.0 million of the Company’s common stock both on the open market and in privately negotiated transactions, from time to time, over the next two years.

37

Item 3. Defaults Upon Senior Securities

None.

Item 4. Mine Safety Disclosures

None.

Item 5. Other Information

None.

38

INDEX TO EXHIBITS

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	The following financial statements from the Company’s Quarterly Report on Form 10-Q for the quarter ended March 31, 2022, formatted in Inline XBRL: (i) Condensed Consolidated Balance Sheets, (ii) Condensed Consolidated Statements of Comprehensive Loss, (iii) Condensed Consolidated Statements of Stockholders’ Equity, (iv) Condensed Consolidated Statements of Cash Flows and (v) Notes to Condensed Consolidated Financial Statements, tagged as blocks of text and including detailed tags.†
104	Cover Page Interactive Data File (formatted as Inline XBRL and contained in Exhibit 101).†

† Filed herewith.

** Furnished, and not filed.

39

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 12, 2022	By:	/s/ JOHN K. KIBARIAN
		John K. Kibarian
		President and Chief Executive Officer
		(principal executive officer)
Date: May 12, 2022	By:	/s/ ADNAN RAZA
		Adnan Raza
		Executive Vice President, Finance and Chief
		Financial Officer
		(principal financial and accounting officer)

40

EX-31.1

Exhibit 31.01

CERTIFICATIONS

I, John K. Kibarian, certify that:

1. I have reviewed this quarterly report on Form 10-Q of PDF Solutions, Inc.;

2. Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to the period covered by this report;

3. Based on my knowledge, the financial statements, and other financial information included in this report, fairly present in all material respects the financial condition, results of operations and cash flows of the registrant as of, and for, the periods presented in this report;

4. The registrant’s other certifying officer(s) and I are responsible for establishing and maintaining disclosure controls and procedures (as defined in Exchange Act Rules 13a-15(e) and 15d-15(e)) and internal control over financial reporting (as defined in Exchange Act Rules 13a-15(f) and 15d-15(f)) for the registrant and have:

(a) Designed such disclosure controls and procedures, or caused such disclosure controls and procedures to be designed under our supervision, to ensure that material information relating to the registrant, including its consolidated subsidiaries, is made known to us by others within those entities, particularly during the period in which this report is being prepared;

(b) Designed such internal control over financial reporting, or caused such internal control over financial reporting to be designed under our supervision, to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles;

(c) Evaluated the effectiveness of the registrant’s disclosure controls and procedures and presented in this report our conclusions about the effectiveness of the disclosure controls and procedures, as of the end of the period covered by this report based on such evaluation; and

(d) Disclosed in this report any change in the registrant’s internal control over financial reporting that occurred during the registrant’s most recent fiscal quarter (the registrant’s fourth fiscal quarter in the case of an annual report) that has materially affected, or is reasonably likely to materially affect, the registrant’s internal control over financial reporting; and

5. The registrant’s other certifying officer(s) and I have disclosed, based on our most recent evaluation of internal control over financial reporting, to the registrant’s auditors and the audit committee of registrant’s board of directors (or persons performing the equivalent functions):

(a) All significant deficiencies and material weaknesses in the design or operation of internal control over financial reporting which are reasonably likely to adversely affect the registrant’s ability to record, process, summarize and report financial information; and

(b) Any fraud, whether or not material, that involves management or other employees who have a significant role in the registrant’s internal control over financial reporting.

	By:	/s/ John K. Kibarian
		John K. Kibarian
		President and Chief Executive Officer
		(principal executive officer)
Date: May 12, 2022

EX-31.2

Exhibit 31.02

CERTIFICATIONS

I, Adnan Raza, certify that:

1. I have reviewed this quarterly report on Form 10-Q of PDF Solutions, Inc.;

2. Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to the period covered by this report;

3. Based on my knowledge, the financial statements, and other financial information included in this report, fairly present in all material respects the financial condition, results of operations and cash flows of the registrant as of, and for, the periods presented in this report;

4. The registrant’s other certifying officer(s) and I are responsible for establishing and maintaining disclosure controls and procedures (as defined in Exchange Act Rules 13a-15(e) and 15d-15(e)) and internal control over financial reporting (as defined in Exchange Act Rules 13a-15(f) and 15d-15(f)) for the registrant and have:

(a) Designed such disclosure controls and procedures, or caused such disclosure controls and procedures to be designed under our supervision, to ensure that material information relating to the registrant, including its consolidated subsidiaries, is made known to us by others within those entities, particularly during the period in which this report is being prepared;

(b) Designed such internal control over financial reporting, or caused such internal control over financial reporting to be designed under our supervision, to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles;

(c) Evaluated the effectiveness of the registrant’s disclosure controls and procedures and presented in this report our conclusions about the effectiveness of the disclosure controls and procedures, as of the end of the period covered by this report based on such evaluation; and

(d) Disclosed in this report any change in the registrant’s internal control over financial reporting that occurred during the registrant’s most recent fiscal quarter (the registrant’s fourth fiscal quarter in the case of an annual report) that has materially affected, or is reasonably likely to materially affect, the registrant’s internal control over financial reporting; and

5. The registrant’s other certifying officer(s) and I have disclosed, based on our most recent evaluation of internal control over financial reporting, to the registrant’s auditors and the audit committee of registrant’s board of directors (or persons performing the equivalent functions):

(a) All significant deficiencies and material weaknesses in the design or operation of internal control over financial reporting which are reasonably likely to adversely affect the registrant’s ability to record, process, summarize and report financial information; and

(b) Any fraud, whether or not material, that involves management or other employees who have a significant role in the registrant’s internal control over financial reporting.

	By:	/s/ Adnan Raza
		Adnan Raza
		Executive Vice President, Finance
		and Chief Financial Officer
		(principal financial and accounting
		officer)
Date: May 12, 2022

EX-32.1

Exhibit 32.01

CERTIFICATION PURSUANT TO

18 U.S.C. SECTION 1350,

AS ADOPTED PURSUANT TO

SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002

In connection with the Quarterly Report of PDF Solutions, Inc. (the “Company”) on Form 10-Q for the quarter ended March 31, 2022, as filed with the Securities and Exchange Commission on May 12, 2022 (the “Report”), I, John K. Kibarian, President and Chief Executive Officer of the Company, certify, pursuant to 18 U.S.C. Section 1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002, that, to my knowledge:

(1) The Report fully complies with the requirements of section 13(a) or 15(d) of the Securities Exchange Act of 1934; and

(2) The information contained in the Report fairly presents, in all material respects, the financial condition and result of operations of the Company.

	By:	/s/ John K. Kibarian
		John K. Kibarian
		President and Chief Executive
		Officer
		(principal executive officer)
Date: May 12, 2022

EX-32.2

Exhibit 32.02

CERTIFICATION PURSUANT TO

18 U.S.C. SECTION 1350,

AS ADOPTED PURSUANT TO

SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002

In connection with the Quarterly Report of PDF Solutions, Inc. (the “Company”) on Form 10-Q for the quarter ended March 31, 2022, as filed with the Securities and Exchange Commission on May 12, 2022 (the “Report”), I, Adnan Raza, Executive Vice President, Finance and Chief Financial Officer of the Company, certify, pursuant to 18 U.S.C. Section 1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002, that, to my knowledge:

(1) The Report fully complies with the requirements of section 13(a) or 15(d) of the Securities Exchange Act of 1934; and

(2) The information contained in the Report fairly presents, in all material respects, the financial condition and result of operations of the Company.

10
	By:	/s/ Adnan Raza
		Adnan Raza
		Executive Vice President, Finance
		and Chief Financial Officer
		(principal financial and accounting
		officer)
Date: May 12, 2022

XML

Document And Entity Information - shares	3 Months Ended
	Mar. 31, 2022	May 06, 2022
Document and Entity Information
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Mar. 31, 2022
Document Transition Report	false
Entity File Number	000-31311
Entity Registrant Name	PDF SOLUTIONS, INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	25-1701361
Entity Address, Address Line One	2858 De La Cruz Blvd.
Entity Address, City or Town	Santa Clara
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	95050
City Area Code	408
Local Phone Number	280-7900
Title of 12(b) Security	Common Stock, $0.00015 par value
Trading Symbol	PDFS
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		36,956,426
Entity Central Index Key	0001120914
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Document Fiscal Period Focus	Q1
Document Fiscal Year Focus	2022

XML

CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Current assets:
Cash and cash equivalents	$ 35,799	$ 27,684
Short-term investments	98,443	112,542
Accounts receivable, net of allowance for doubtful accounts of $902 and $890 in 2022 and 2021, respectively	37,753	40,087
Prepaid expenses and other current assets	8,857	8,194
Total current assets	180,852	188,507
Property and equipment, net	36,844	35,295
Operating lease right-of-use assets, net	4,479	5,408
Goodwill	14,123	14,123
Intangible assets, net	20,372	21,239
Deferred tax assets, net	67	75
Other non-current assets	8,840	9,121
Total assets	265,577	273,768
Current liabilities:
Accounts payable	4,053	5,554
Accrued compensation and related benefits	8,576	9,495
Accrued and other current liabilities	4,602	3,328
Operating lease liabilities - current portion	1,225	1,758
Deferred revenues - current portion	23,868	23,691
Billings in excess of recognized revenues	245
Total current liabilities	42,569	43,826
Long-term income taxes payable	2,666	2,656
Non-current operating lease liabilities	4,741	5,258
Other non-current liabilities	2,034	2,443
Total liabilities	52,010	54,183
Commitments and contingencies (Note 12)
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 47,929 and 47,414, respectively; shares outstanding 37,594 and 37,411, respectively	6	6
Additional paid-in-capital	430,799	423,069
Treasury stock at cost, 10,335 and 10,003 shares, respectively	(113,872)	(104,705)
Accumulated deficit	(101,871)	(97,721)
Accumulated other comprehensive loss	(1,495)	(1,064)
Total stockholders' equity	213,567	219,585
Total liabilities and stockholders' equity	$ 265,577	$ 273,768

XML

CONDENSED CONSOLIDATED BALANCE SHEETS (Parentheticals) - USD ($) shares in Thousands, $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
CONDENSED CONSOLIDATED BALANCE SHEETS
Accounts receivable, allowance for doubtful accounts	$ 902	$ 890
Preferred stock, par value (in dollars per share)	$ 0.00015	$ 0.00015
Preferred stock, shares authorized (in shares)	5,000	5,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.00015	$ 0.00015
Common stock, shares authorized (in shares)	70,000	70,000
Common stock, shares issued (in shares)	47,929	47,414
Common stock, shares outstanding (in shares)	37,594	37,411
Treasury stock, shares (in shares)	10,335	10,003

XML

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Revenues:
Revenues	$ 33,498	$ 24,200
Costs and Expenses:
Costs of revenues	11,529	10,663
Research and development	14,089	10,841
Selling, general and administrative	10,839	9,464
Amortization of acquired intangible assets	314	314
Interest and other expense (income), net	(310)	(441)
Loss before income taxes	(2,963)	(6,641)
Income tax expense	1,187	956
Net loss	(4,150)	(7,597)
Other comprehensive loss:
Foreign currency translation adjustments, net of tax	(397)	(530)
Change in unrealized losses related to available-for-sale debt securities, net of tax	(34)	2
Total other comprehensive income loss	(431)	(528)
Comprehensive loss	$ (4,581)	$ (8,125)
Net loss per share, basic (in dollars per share)	$ (0.11)	$ (0.21)
Net loss per share, diluted (in dollars per share)	$ (0.11)	$ (0.21)
Weighted average common shares used to calculate net loss per share, basic (in shares)	37,606	36,974
Weighted average common shares used to calculate net loss per share, diluted (in shares)	37,606	36,974
Analytics [Member]
Revenues:
Revenues	$ 30,426	$ 19,393
Integrated Yield Ramp [Member]
Revenues:
Revenues	$ 3,072	$ 4,807

XML

CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS EQUITY - USD ($) shares in Thousands, $ in Thousands	Common Stock Outstanding [Member]	Additional Paid-in Capital [Member]	Treasury Stock [Member]	Retained Earnings [Member]	AOCI Attributable to Parent [Member]	Total
Balances (in shares) at Dec. 31, 2020	36,850		9,550
Balances at Dec. 31, 2020	$ 6	$ 407,173	$ (96,215)	$ (76,233)	$ (225)	$ 234,506
Issuance of common stock in connection with employee stock purchase plan (in shares)	100
Issuance of common stock in connection with employee stock purchase plan		921				921
Issuance of common stock in connection with exercise of options (in shares)	81
Issuance of common stock in connection with exercise of options		568				568
Vesting of restricted stock units (in shares)	149
Purchases of treasury stock in connection with tax withholdings on restricted stock grants (in shares)			73
Purchases of treasury stock in connection with tax withholdings on restricted stock grants			$ (1,463)			(1,463)
Repurchase of common stock (in shares)	(251)		251
Repurchase of common stock			$ (4,523)			(4,523)
Stock-based compensation expense		3,369				3,369
Comprehensive income (loss)				(7,597)	(528)	(8,125)
Balances (in shares) at Mar. 31, 2021	36,929		9,874
Balances at Mar. 31, 2021	$ 6	412,031	$ (102,201)	(83,830)	(753)	225,253
Balances (in shares) at Dec. 31, 2021	37,411		10,003
Balances at Dec. 31, 2021	$ 6	423,069	$ (104,705)	(97,721)	(1,064)	219,585
Issuance of common stock in connection with employee stock purchase plan (in shares)	95
Issuance of common stock in connection with employee stock purchase plan		1,502				$ 1,502
Issuance of common stock in connection with exercise of options (in shares)	75					75
Issuance of common stock in connection with exercise of options		675				$ 675
Vesting of restricted stock units (in shares)	232
Purchases of treasury stock in connection with tax withholdings on restricted stock grants (in shares)			113
Purchases of treasury stock in connection with tax withholdings on restricted stock grants			$ (3,389)			(3,389)
Repurchase of common stock (in shares)	(219)		219
Repurchase of common stock			$ (5,778)			(5,778)
Stock-based compensation expense		5,553				5,553
Comprehensive income (loss)				(4,150)	(431)	(4,581)
Balances (in shares) at Mar. 31, 2022	37,594		10,335
Balances at Mar. 31, 2022	$ 6	$ 430,799	$ (113,872)	$ (101,871)	$ (1,495)	$ 213,567

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CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Cash flows from operating activities:
Net loss	$ (4,150)	$ (7,597)
Adjustments to reconcile net loss to net cash provided by (used in) operating activities:
Depreciation and amortization	1,380	1,718
Stock-based compensation expense	5,553	3,369
Amortization of acquired intangible assets	867	849
Amortization of costs capitalized to obtain revenue contracts	173	165
Loss on disposal and write-down in value of property and equipment		5
Deferred taxes	(11)	55
Other	37	(20)
Changes in operating assets and liabilities:
Accounts receivable	2,296	(677)
Prepaid expenses and other current assets	(976)	2,839
Operating lease right-of-use assets	918	476
Other non-current assets	278	339
Accounts payable	(2,069)	(4,109)
Accrued compensation and related benefits	(864)	(2,059)
Accrued and other liabilities	582	(162)
Deferred revenues	(225)	(1,994)
Billings in excess of recognized revenues	245	(998)
Operating lease liabilities	(1,038)	(524)
Net cash provided by (used in) operating activities	2,996	(8,325)
Cash flows from investing activities:
Proceeds from maturities and sales of short-term investments	35,000	68,000
Purchases of short-term investments	(20,959)	(10,997)
Purchases of property and equipment	(1,765)	(586)
Net cash provided by investing activities	12,276	56,417
Cash flows from financing activities:
Proceeds from exercise of stock options	675	568
Proceeds from employee stock purchase plan	1,502	921
Payments for taxes related to net share settlement of equity awards	(3,389)	(1,463)
Repurchases of common stock	(5,778)	(4,523)
Net cash used in financing activities	(6,990)	(4,497)
Effect of exchange rate changes on cash and cash equivalents	(167)	(104)
Net change in cash, cash equivalents, and restricted cash	8,115	43,491
Cash, cash equivalents, and restricted cash at beginning of period	27,684	33,815
Cash, cash equivalents, and restricted cash at end of period	35,799	77,306
Reconciliation of cash, cash equivalents, and restricted cash to the balance sheets:
Cash and cash equivalents	35,799	74,287
Restricted cash		3,019
Total cash, cash equivalents and restricted cash	35,799	77,306
Supplemental disclosure of cash flow information:
Cash paid during the period for taxes	1,254	530
Cash paid for amounts included in the measurement of operating lease liabilities	430	651
Supplemental disclosure of noncash information:
Property and equipment received and accrued in accounts payable and accrued and other liabilities	1,923	181
Advances for purchase of fixed assets transferred from prepaid assets to property and equipment	$ 120
Release of restricted cash reducing goodwill due to the acquisition purchase price adjustment		$ 469

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Note 1 - BASIS OF PRESENTATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

3 Months Ended

Mar. 31, 2022

BASIS OF PRESENTATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

BASIS OF PRESENTATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

1. BASIS OF PRESENTATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

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, 2021.

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

The condensed consolidated balance sheet at December 31, 2021, has been derived from the audited consolidated financial statements but does not include all disclosures required by accounting principles generally accepted in the United States of America.

Use of Estimates

The preparation of financial statements in conformity with generally accepted accounting principles in the United States (“U.S. GAAP”) requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Significant estimates in these financial statements include revenue recognition, the estimated useful lives of property and equipment and intangible assets, assumptions made in analysis of allowance for doubtful accounts, fair values of assets acquired and liabilities assumed in business combinations, impairment of goodwill and long-lived assets, valuation for deferred tax assets, and accounting for lease obligations, stock-based compensation expense, and income tax uncertainties and contingencies. Actual results could differ from those estimates and may result in material effects on the Company’s operating results and financial position.

The global COVID-19 pandemic has impacted the operations and purchasing decisions of companies worldwide. As of the date of issuance of the condensed consolidated financial statements, the Company is not aware of any specific event or circumstance relating to COVID-19 that would require updates to the Company’s estimates and judgments or revisions to the carrying value of its assets or liabilities. These estimates may change, as new events occur and additional information is obtained, and are recognized in the condensed consolidated financial statements as soon as they become known. Actual results could differ from those estimates and any such differences may be material to the financial statements.

Recent Accounting Standards

Accounting Standards Adopted

Management has reviewed recently issued accounting pronouncements and has determined there are not any that would have a material impact on the condensed consolidated financial statements.

Accounting Standards Not Yet Adopted

In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments – Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments (ASU 2016-13), which requires measurement and recognition of expected credit losses for financial assets held at the reporting date based on internal information, external information, or a combination of both relating to past events, current conditions, and reasonable and supportable forecasts. ASU No. 2016-13 replaces the existing incurred loss impairment model with a forward-looking expected credit loss model, which will result in earlier recognition of credit losses. Subsequent to the issuance of ASU No. 2016-13, the FASB issued ASU No. 2018-19, Codification Improvements to Topic 326, Financial Instruments – Credit Losses, ASU No. 2019-04, Codification Improvements to Topic 326, Financial Instruments – Credit Losses, Topic 815, Derivatives and Hedging, and Topic 825, Financial Instrument, ASU No. 2019-05, Financial Instruments – Credit Losses (Topic 326) Targeted Transition Relief, ASU No. 2016-13, ASU No. 2019-10 Financial Instruments-Credit Losses (Topic 326), Derivatives and Hedging (Topic 815), and Leases (Topic 842), and ASU No. 2019-11 Codification Improvements to Topic 326, Financial Instruments-Credit Losses. The subsequent ASUs do not change the core principle of the guidance in ASU No. 2016-13. Instead, these amendments are intended to clarify and improve operability of certain topics included within ASU No. 2016-13.

Additionally, ASU No. 2019-10 defers the effective date for the adoption of the new standard on credit losses for public filers that are considered small reporting companies (“SRC”) as defined by the SEC to fiscal years beginning after December 15, 2022, including interim periods within those fiscal years, which will be fiscal 2023 for the Company if it continues to be classified as an SRC. In February 2020, the FASB issued ASU 2020-02, which provides guidance regarding methodologies, documentation, and internal controls related to expected credit losses. The subsequent amendments will have the same effective date and transition requirements as ASU No. 2016-13. Early adoption is permitted. Topic 326 requires a modified retrospective approach by recording a cumulative-effect adjustment to retained earnings as of the beginning of the period of adoption. While the Company is currently evaluating the impact of Topic 326, the Company does not expect the adoption of this ASU to have a material impact on its condensed consolidated financial statements or the related disclosure.

In August 2020, the FASB issued ASU No. 2020-06, Debt – Debt with Conversion and Other Options (Subtopic 470-20) and Derivatives and Hedging – Contracts in Entity’s Own Equity (Subtopic 815-20): Accounting for Convertible Instruments and Contracts in an Entity’s Own Equity, which is intended to simplify the accounting for certain financial instruments with characteristics of liabilities and equity, including convertible instruments and contracts on an entity’s own equity. The guidance allows for either full retrospective adoption or modified retrospective adoption. Additionally, the ASU will require entities to use the “if-converted” method when calculating diluted earnings per share for convertible instruments. The ASU will be effective for annual reporting periods beginning after December 15, 2023 for SRCs and interim periods within those annual periods. Early adoption is permitted. The Company does not anticipate that the adoption of this ASU will have a significant impact on its condensed consolidated financial statements or the related disclosures.

Management has reviewed other recently issued accounting pronouncements issued or proposed by the FASB, and does not believe any of these accounting pronouncements has had or will have a material impact on the condensed consolidated financial statements.

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Note 2 - REVENUE FROM CONTACTS WITH CUSTOMERS

3 Months Ended

Mar. 31, 2022

REVENUE FROM CONTRACTS WITH CUSTOMERS

REVENUE FROM CONTRACT WITH CUSTOMERS

2. REVENUE FROM CONTRACTS WITH CUSTOMERS

The Company derives revenue from two sources: Analytics revenue and Integrated Yield Ramp revenue.

The Company recognizes revenue in accordance with FASB ASC Topic 606, Revenue from Contracts with Customers, and its related amendments (collectively known as “ASC 606”). ASC 606 outlines a single comprehensive model to use in accounting for revenue arising from contracts with customers. Revenue is recognized when control of products or services is transferred to customers, in an amount that reflects the consideration the Company expects to be entitled to in exchange for those promised products or services.

The Company determines revenue recognition through the following five steps:

● Identification of the contract, or contracts, with a customer

● Identification of the performance obligations in the contract

● Determination of the transaction price

● Allocation of the transaction price to the performance obligations in the contract

● Recognition of revenue when, or as, performance obligations are satisfied

The Company accounts for a contract when it has approval and commitment from both parties, the rights of the parties are identified, payment terms are identified, the contract has commercial substance, and collectability of consideration is probable.

Contracts with multiple performance obligations

The Company enters into contracts that can include various combinations of licenses, products and services, some of which are distinct and are accounted for as separate performance obligations. For contracts with multiple performance obligations, the Company allocates the transaction price of the contract to each performance obligation on a relative basis using the standalone selling price (“SSP”).

Analytics Revenue

Analytics revenue is derived from the following primary offerings: licenses and services for standalone software (which is primarily Exensio^® and Cimetrix^® products), SaaS (which is primarily Exensio products), and DFI™ systems and CV^® systems that do not include performance incentives based on customers’ yield achievement.

Revenue from standalone software is recognized depending on whether the license is perpetual or time-based. Perpetual (one-time charge) license software is recognized at the time of the inception of the arrangement when control transfers to the customers, if the software license is considered as a separate performance obligation from the services offered by the Company. Revenue from post-contract support is recognized over the contract term on a straight-line basis, because we are providing (i) support and (ii) unspecified software updates on a when-and-if available basis over the contract term. Revenue from time-based-licensed software is allocated to each performance obligation and is recognized either at a point in time or over time as follows. The license component is recognized at the time when control transfers to customers, with the post-contract support component recognized ratably over the committed term of the contract. For contracts with any combination of licenses, support, and other services, distinct performance obligations are accounted for separately. For contracts with multiple performance obligations, we allocate the transaction price of the contract to each performance obligation on a relative basis using the SSP attributed to each performance obligation.

Revenue from SaaS arrangements, which allow for the use of a cloud-based software product or service over a contractually determined period of time without the customer having to take possession of software, is accounted for as a subscription and is recognized as revenue ratably, on a straight-line basis, over the subscription period beginning on the date the service is first made available to customers. For contracts with any combination of SaaS and related services, distinct performance obligations are accounted for separately. For contracts with multiple performance obligations, we allocate the transaction price of the contract to each performance obligation on a relative basis using the SSP attributed to each performance obligation.

Revenue from DFI systems and CV systems that do not include performance incentives based on customers’ yield achievement is recognized primarily as services are performed. Where there are distinct performance obligations, the Company allocates revenue to all deliverables based on their SSPs. For those contracts with multiple performance obligations, the Company allocates the transaction price of the contract to each performance obligation on a relative basis using the SSP attributed to each performance obligation. Where there are not discrete performance obligations, historically, revenue is primarily recognized as services are performed using a percentage of completion method based on costs or labor-hours inputs, whichever is the most appropriate measure of the progress towards completion of the contract. The estimation of percentage of completion method is complex and subject to many variables that require significant judgement. Please refer to “Significant Judgments” section of this Note for further discussion.

Integrated Yield Ramp Revenue

Integrated Yield Ramp revenue is derived from the Company’s fixed-fee engagements that include performance incentives based on customers’ yield achievement (which consists primarily of Gainshare royalties) typically based on customer’s wafer shipments, pertaining to these fixed-price contracts, which royalties are variable.

Revenue under these project–based contracts, which are delivered over a specific period of time, typically for a fixed fee component paid on a set schedule, is recognized as services are performed using a percentage of completion method based on costs or labor-inputs, whichever is the most appropriate measure of the progress towards completion of the contract. Where there are distinct performance obligations, the Company allocates revenue to all deliverables based on their SSPs and allocates the transaction price of the contract to each performance obligation on a relative basis using SSP. Similar to the services provided in connection with DFI systems and CV systems that are contributing to Analytics revenue, due to the nature of the work performed in these arrangements, the estimation of percentage of completion method is complex and subject to many variables that require significant judgement. Please refer to “Significant Judgments” section of this Note for further discussion.

The Gainshare royalty contained in IYR contracts is a variable fee related to continued usage of the Company’s intellectual property after the fixed-fee service period ends, based on a customer’s yield achievement. Revenue derived from Gainshare is contingent upon the Company’s customers reaching certain defined production yield levels. Gainshare royalty periods are generally subsequent to the delivery of all contractual services and performance obligations. The Company records Gainshare as a usage-based royalty derived from customers’ usage of intellectual property and records it in the same period in which the usage occurs.

Disaggregation of Revenue

The Company disaggregates revenue from contracts with customers into the timing of the transfer of goods and services and the geographical regions. The Company determined that disaggregating revenue into these categories achieves the disclosure objective to depict how the nature, amount, timing, and uncertainty of revenue and cash flows are affected by economic factors.

The Company’s performance obligations are satisfied either over time or at a point-in-time. The following table represents a disaggregation of revenue by timing of revenue:

	Three Months Ended March 31,
	2022		2021
Over time	70	%	50	%
Point-in-time	30	%	50	%
Total	100	%	100	%

International revenues accounted for approximately 48% and 65% of our total revenues during the three months ended March 31, 2022 and March 31, 2021, respectively. See Note 10, Customer and Geographic Information.

Significant Judgments

Judgments and estimates are required under ASC 606. Due to the complexity of certain contracts, the actual revenue recognition treatment required under ASC 606 for the Company’s arrangements may be dependent on contract-specific terms and may vary in some instances.

For revenue under project-based contracts for fixed-price implementation services, revenue is recognized as services are performed using a percentage-of-completion method based on costs or labor-hours input method, whichever is the most appropriate measure of the progress towards completion of the contract. Due to the nature of the work performed in these arrangements, the estimation of percentage of completion method is complex, subject to many variables and requires significant judgment. Key factors reviewed by the Company to estimate costs to complete each contract are future labor and product costs and expected productivity efficiencies. If circumstances arise that change the original estimates of revenues,

costs, or extent of progress toward completion, revisions to the estimates are made. These revisions may result in increases or decreases in estimated revenues or costs, and such revisions are reflected in revenue on a cumulative catch-up basis in the period in which the circumstances that gave rise to the revision become known.

The Company’s contracts with customers often include promises to transfer products, licenses software and provide services, including professional services, technical support services, and rights to unspecified updates to a customer. Determining whether licenses and services are distinct performance obligations that should be accounted for separately, or not distinct and thus accounted for together, requires significant judgment. The Company rarely licenses software on a standalone basis, so the Company is required to estimate the range of SSPs for each performance obligation. In instances where SSP is not directly observable because the Company does not license the software or sell the service separately, the Company determines the SSP using information that may include market conditions and other observable inputs.

The Company is required to record Gainshare royalty revenue in the same period in which the usage occurs. Because the Company generally does not receive the acknowledgment reports from its customers during a given quarter within the time frame necessary to adequately review the reports and include the actual amounts in quarterly results for such quarter, the Company accrues the related revenue based on estimates of customers underlying sales achievement. The Company’s estimation process can be based on historical data, trends, seasonality, changes in the contract rate, knowledge of the changes in the industry and changes in the customer’s manufacturing environment learned through discussions with customers and sales personnel. As a result of accruing revenue for the quarter based on such estimates, adjustments will be required in the following quarter to true-up revenue to the actual amounts reported.

Contract Balances

The Company performs its obligations under a contract with a customer by licensing software or providing services in exchange for consideration from the customer. The timing of the Company’s performance often differs from the timing of the customer’s payment, which results in the recognition of a receivable, a contract asset or a contract liability.

The Company classifies the right to consideration in exchange for software or services transferred to a customer as either a receivable or a contract asset. A receivable is a right to consideration that is unconditional, as compared to a contract asset, which is a right to consideration that is conditional upon factors other than the passage of time. The majority of the Company’s contract assets represent unbilled amounts related to fixed-price service contracts when the revenue recognized exceeds the amount billed to the customer. The contract assets are generally classified as current and are recorded on a net basis with deferred revenue (i.e. contract liabilities) at the contract level. At March 31, 2022 and December 31, 2021, the total contract assets included in prepaid expenses and other current assets in the Condensed Consolidated Balance Sheets $0.4 million and $0.4 million, respectively. The Company did not record any asset impairment charges related to contract assets for the periods presented.

Deferred revenues consist substantially of amounts invoiced in advance of revenue recognition and are recognized as the revenue recognition criteria are met. Deferred revenues that will be recognized during the succeeding twelve-month period are recorded as current deferred revenues and the remaining portion is recorded in the other non-current liabilities in the Condensed Consolidated Balance Sheets. At March 31, 2022 and December 31, 2021, the non-current portion of deferred revenues included in non-current liabilities was $2.0 million and $2.4 million, respectively. Revenue recognized that was included in the deferred revenues and billings in excess of recognized revenues balances at the beginning of each reporting period was $6.9 million and $6.3 million during the three months ended March 31, 2022 and 2021, respectively.

At March 31, 2022, the aggregate amount of the transaction price allocated to the remaining performance obligations related to customer contracts that were unsatisfied or partially unsatisfied was approximately $196.8 million. Given the applicable contract terms with customers, the majority of this amount is expected to be recognized as revenue over the next two years, with the remainder in the following three years. This amount does not include insignificant contracts to which the customer is not committed, nor significant contracts for which we recognize revenue equal to the amount we have the right to invoice for services performed, or future sales-based or usage-based royalty payments in exchange for a license of intellectual property. This amount is subject to change due to future revaluations of variable consideration, terminations, other contract modifications, or currency adjustments. The estimated timing of the recognition of remaining unsatisfied performance

obligations is subject to change and is affected by changes to the scope, change in timing of delivery of products and services, or contract modifications.

The adjustment to revenue recognized from performance obligations satisfied (or partially satisfied) in previous periods was an increase of $0.2 million and a decrease $0.3 million during the three months ended March 31, 2022 and 2021, respectively. These amounts primarily represent changes in estimated percentage-of-completion based contracts and changes in actual versus estimated Gainshare royalty.

Costs to obtain or fulfill a contract

The Company capitalizes the incremental costs to obtain or fulfill a contract with a customer, including direct sales commissions and related fees, when it expects to recover those costs. Amortization expense related to these capitalized costs is recognized over the period associated with the revenue from which the cost was incurred. Total capitalized direct sales commission costs included in prepaid expenses and other current assets in the accompanying Condensed Consolidated Balance Sheets as of March 31, 2022, and December 31, 2021, were $0.9 million and $0.6 million, respectively. Total capitalized direct sales commission costs included in other non-current assets in the accompanying Condensed Consolidated Balance Sheets as of March 31, 2022, and December 31, 2021, were $2.1 million and $2.1 million, respectively. Amortization of these assets were $0.2 million and $0.2 million during the three months ended March 31, 2022 and 2021, respectively. There was no impairment loss in relation to the costs capitalized for the periods presented.

Practical expedient

The Company does not adjust the transaction price for the effects of a significant financing component when the period between the transfers of the promised good or service to the customer and payment for that good or service by the customer is expected to be one year or less. The Company assessed each of its revenue generating arrangements in order to determine whether a significant financing component exists, and determined its contracts did not include a significant financing component during the three months ended March 31, 2022 and 2021.

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Note 3 - STRATEGIC PARTNERSHIP AGREEMENT WITH ADVANTEST AND RELATED PARTY TRANSACTIONS

3 Months Ended

Mar. 31, 2022

STRATEGIC PARTNERSHIP AGREEMENT WITH ADVANTEST AND RELATED PARTY TRANSACTIONS

STRATEGIC PARTNERSHIP AGREEMENT WITH ADVANTEST AND RELATED PARTY TRANSACTIONS

3. STRATEGIC PARTNERSHIP AGREEMENT WITH ADVANTEST AND RELATED PARTY TRANSACTIONS

On July 29, 2020, the Company entered into a long-term strategic partnership with Advantest Corporation through its wholly-owned subsidiary, Advantest America, Inc. (collectively referred to herein as “Advantest”) that included the following agreements.

● A Securities Purchase Agreement for the purchase by Advantest of an aggregate of 3,306,924 shares of the Company’s common stock for aggregate gross proceeds of $65.2 million and a related Stockholder Agreement.

● An Amendment #1 to that certain Software License and Related Services Agreement, dated as of March 25, 2020, for an exclusive commercial arrangement in which the Company and Advantest collaborate on, and the Company initially hosts, develops and maintains, an Advantest-specific cloud layer on the Exensio platform.

● An Amended and Restated Master Development Agreement with Advantest, pursuant to which the Company and Advantest agreed to collaborate on extensions to or combinations of both of their existing technology and new technology to address mutual customers’ needs through one or more development phases subject to certain conditions as set forth therein. Costs and expenses incurred related to this agreement have not been significant for the three months ended March 31, 2022 and 2021.

● A Master Commercial Terms and Support Services Agreement for the commercialization and support of integrated products of the Company and Advantest that are the outcome of the above development agreement. No material costs and expenses were incurred related to the Commercial Agreement with Advantest during the three months ended March 31, 2022 and 2021.

Analytics revenue recognized from Advantest was $2.6 million during the three months ended March 31, 2022 and $2.6 million during the three months ended March 31, 2021. There were no outstanding accounts receivable from Advantest as of March 31, 2022, and December 31, 2021, and deferred revenue amounted to $4.2 million and $6.8 million as of March 31, 2022 and December 31, 2021, respectively. There was no occurrence of any termination events under these agreements as of the issuance of these condensed consolidated financial statements.

The Company carries out transactions with Advantest on arm’s length commercial customary terms.

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Note 4 - BALANCE SHEET COMPONENTS

3 Months Ended

Mar. 31, 2022

BALANCE SHEET COMPONENTS

BALANCE SHEET COMPONENTS

4. BALANCE SHEET COMPONENTS

Accounts receivable

Accounts receivable include amounts that are unbilled at the end of the period that are expected to be billed and collected within a 12-month period. Unbilled accounts receivable, included in accounts receivable, totaled $10.8 million and $11.8 million as of March 31, 2022, and December 31, 2021, respectively. Unbilled accounts receivable that are not expected to be billed and collected during the succeeding 12-month period is recorded in other non-current assets and totaled $1.3 million and $1.3 million as of March 31, 2022, and December 31, 2021, respectively.

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

Property and equipment

Property and equipment, net consist of the following (in thousands):

	March 31,		December 31,
	2022		2021
Computer equipment	$	11,887	$	11,924
Software		5,411		5,419
Furniture, fixtures and equipment		2,503		2,506
Leasehold improvements		6,266		6,272
Laboratory and other equipment		4,171		3,981
Test equipment		28,060		24,452
Construction-in-progress		21,263		22,158
		79,561		76,712
Less: accumulated depreciation and amortization		(42,717)		(41,417)
Total	$	36,844	$	35,295

Test equipment includes DFI systems assets at customer sites that are contributing to revenue. The construction-in-progress balance related to construction of DFI™ systems assets totaled $18.5 million and $20.0 million as of March 31, 2022, and December 31, 2021, respectively. Depreciation and amortization expense was $1.4 million and $1.7 million during the three months ended March 31, 2022 and 2021, respectively.

In the fourth quarter of 2021, the Company wrote down the value of its property and equipment by $3.2 million related to its first-generation of e-beam tools for DFI™ systems wherein carrying values may not be fully recoverable due to lack of market demand and future needs of our customers for these tools.

Goodwill and Intangible Assets, Net

As of March 31, 2022, and December 31, 2021, the carrying amount of goodwill was $14.1 million.

Intangible assets, net, consisted of the following (in thousands):

		March 31, 2022						December 31, 2021
	Amortization	Gross				Net		Gross				Net
	Period	Carrying		Accumulated		Carrying		Carrying		Accumulated		Carrying
	(Years)	Amount		Amortization		Amount		Amount		Amortization		Amount
Acquired identifiable intangibles:
Customer relationships	1-10	$	9,407	$	(6,202)	$	3,205	$	9,407	$	(6,041)	$	3,366
Developed technology	4-9		33,635		(17,848)		15,787		33,635		(17,250)		16,385
Tradename and trademarks	2-10		1,598		(839)		759		1,598		(812)		786
Patent	7-10		1,800		(1,650)		150		1,800		(1,640)		160
Noncompetition agreements	3		848		(377)		471		848		(306)		542
Total		$	47,288	$	(26,916)	$	20,372	$	47,288	$	(26,049)	$	21,239

The weighted average amortization period for acquired identifiable intangible assets was 6.6 years as of March 31, 2022. The following table summarizes intangible assets amortization expense in the Condensed Consolidated Statements of Comprehensive Loss (in thousands):

	Three Months Ended March 31,
	2022		2021
Amortization of acquired technology included under Costs of Revenues	$	553	$	535
Amortization of acquired intangible assets presented separately under Costs and Expenses		314		314
Total amortization of acquired intangible assets	$	867	$	849

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

Year Ending December 31,	Amount
2022 (remaining nine months)	$	2,601
2023		3,444
2024		3,046
2025		2,882
2026		2,712
2027 and thereafter		5,687
Total future amortization expense	$	20,372

There were no impairment charges for goodwill and intangible assets during the three months ended March 31, 2022 or 2021.

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Note 5 - LEASES

3 Months Ended

Mar. 31, 2022

LEASES

LEASES

5. LEASES

The Company leases administrative and sales offices and certain equipment under non-cancellable 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 dates through 2028. The Company had no leases that were classified as a financing lease as of March 31, 2022, and December 31, 2021.

In the first quarter of 2022, the Company early terminated an office lease contract. The termination of this lease reduces the Company’s operating lease right-of-use assets and lease liabilities by approximately $0.5 million and $0.6 million, respectively. The gain from the lease termination of approximately $0.1 million was recorded under selling, general and administrative expense in the Condensed Consolidated Statement of Comprehensive Loss for the three months ended March 31, 2022.

Lease expense was comprised of the following (in thousands):

	Three Months Ended March 31,
	2022		2021
Operating lease expense (1)	$	345	$	485
Short-term lease and variable lease expense (2)		283		174
Total lease expense	$	628	$	659

(1) Net of gain recognized upon lease termination of $0.1 million in three month ended March 31, 2022.

(2) Leases with an initial term of 12 months or less are not recorded on the Condensed Consolidated Balance Sheets, and the Company recognizes lease expense for these leases on a straight-line basis over the lease term. Variable lease expense for the periods presented primarily included common area maintenance charges.

Supplemental balance sheets information related to operating leases was as follows:

	March 31,			December 31,
	2022			2021
Weighted average remaining lease term under operating ROU leases (in years)		6.0			5.7
Weighted average discount rate for operating lease liabilities		5.25	%		5.25	%

Maturities of operating lease liabilities as of March 31, 2022, were as follows (in thousands):

Year Ending December 31,	Amount (1)
2022 (remaining nine months)	$	960
2023		1,137
2024		1,070
2025		1,086
2026		1,053
2027 and thereafter		1,650
Total future minimum lease payments	$	6,956
Less: Interest (2)		(990)
Present value of future minimum lease payments under operating lease liabilities (3)	$	5,966

(1) As of March 31, 2022, the total operating lease liability includes approximately $1.1 million related to an option to extend a lease term that is reasonably certain to be exercised.

(2) Calculated using incremental borrowing interest rate for each lease.

(3) Includes the current portion of operating lease liabilities of $1.2 million as of March 31, 2022.

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Note 6 - STOCKHOLDERS EQUITY

3 Months Ended

Mar. 31, 2022

STOCKHOLDERS EQUITY

STOCKHOLDERS EQUITY

6. STOCKHOLDERS’ EQUITY

Stock Repurchase Program

On June 4, 2020, the Company’s Board of Directors adopted a stock repurchase program (the “2020 Program”) to repurchase up to $25.0 million of the Company’s common stock both on the open market and in privately negotiated transactions, including through Rule 10b5-1 plans, over the next two years. During the three months ended March 31, 2022, 218,858 shares were repurchased under the 2020 Program at an average price of $26.40 per share for an aggregate total price of $5.8 million. During the three months ended March 31, 2021, approximately 251,000 shares were repurchased under the 2020 Program at an average price of $18.01 per share for an aggregate total price of $4.5 million. Through March 31, 2022, approximately 470,000 shares had been repurchased at an average price of $21.91 per share, for a total price of $10.3 million under the 2020 Program.

On April 11, 2022, the Board of Directors terminated that 2020 Program, and adopted a new program (the “2022 Program”) to repurchase up to $35.0 million of the Company’s common stock both on the open market and in privately negotiated transactions, from time to time, over the next two years.

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Note 7 - EMPLOYEE BENEFIT PLANS

3 Months Ended

Mar. 31, 2022

EMPLOYEE BENEFIT PLANS

EMPLOYEE BENEFIT PLANS

7. EMPLOYEE BENEFIT PLANS

On March 31, 2022, the Company had the following stock-based compensation plans:

Employee Stock Purchase Plan

In July 2001, the Company’s stockholders initially approved the 2001 Employee Stock Purchase Plan, which was subsequently amended and restated in 2010 (as amended, the “2010 Purchase Plan”) to extend the term of the plan through May 17, 2020. Under the 2010 Purchase Plan, eligible employees could contribute up to 10% of their compensation, as defined in the 2010 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 2010 Purchase Plan provided for twenty-four-month offering periods with four six-month purchase periods in each offering period. The 2010 Purchase Plan expired on May 17, 2020. Existing offering periods under the 2010 Plan continued through the applicable expiration date and the final offering period expired on January 31, 2022. On June 15, 2021, the Company’s stockholders approved the 2021 Employee Stock Purchase Plan, which has a ten-year term (the “2021 Purchase Plan”). The terms of 2021 Purchase Plan are substantially similar to those of the 2010 Purchase Plan. A twenty-four-month offering period under the 2021 Purchase Plan commenced on August 1, 2021.

The Company estimated the fair value of purchase rights granted under the 2010 and the 2021 Purchase Plans 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:

	2021 Purchase Plan			2010 Purchase Plan
	Three Months Ended March 31,			Three Months Ended March 31,
	2022			2021
Expected life (in years)		1.25			1.25
Volatility		48.90	%		34.25	%
Risk-free interest rate		0.86	%		1.43	%
Expected dividend		—			—
Weighted average fair value of purchase rights granted during the period	$	10.76		$	4.83

During the three months ended March 31, 2022, a total of approximately 95,243 shares were issued at a weighted-average purchase price of $15.77 per share. During the three months ended March 31, 2021, a total of approximately 99,674 shares were issued at a weighted-average purchase price of $9.24 per share. As of March 31, 2022, unrecognized compensation cost related to the 2021 Purchase Plan was $1.9 million. These costs are expected to be recognized over a weighted average period of 1.4 years.

Stock Incentive Plans

On November 16, 2011, the Company’s stockholders initially approved the 2011 Stock Incentive Plan, which has been amended and restated and approved by the Company’s stockholders a number of times since then (as amended, the “2011 Plan”). Under the 2011 Plan, the Company may award stock options, stock appreciation rights (“SARs”), 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 11,550,000 shares, plus up to 3,500,000 shares previously issued under the 2001 Stock Plan adopted by the Company in 2001, which expired in 2011 (the “2001 Plan”) that are either (i) forfeited or (ii) repurchased by the Company or are 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 SARs, the aggregate number of shares reserved under the 2011 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 26, 2022, the Company’s Board of Directors amended the 2011 Plan, subject to stockholder approval, to increase the number of shares reserved for awards under it to a total of 12,800,000 shares, which is an increase of an additional 1,250,000 shares.

As of March 31, 2022, 12.1 million shares of common stock were reserved to cover stock-based awards under the 2011 Plan, of which 3.2 million shares were available for future grant. The number of shares reserved and available under the 2011 Plan includes 0.5 million shares that were subject to awards previously made under the 2001 Plan and were forfeited, expired or repurchased by the Company after the adoption of the 2011 Plan through March 31, 2022. As of March 31, 2022, there were no outstanding awards that had been granted outside of the 2011 or 2001 Plans (collectively, the “Stock Plans”).

The Company estimated the fair value of share-based awards granted under the 2011 Stock Plan during the period using the Black-Scholes-Merton option-pricing model. There were no stock options granted during the three months ended March 31, 2022 and 2021.

Stock-Based Compensation

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

	Three Months Ended March 31,
	2022		2021
Costs of revenues	$	728	$	652
Research and development		3,168		1,588
Selling, general and administrative		1,657		1,129
Stock-based compensation expenses	$	5,553	$	3,369

Additional information with respect to options under the Stock Plans during the three months ended March 31, 2022, is as follows:

	Outstanding Options
				Weighted
		Weighted		Average
		Average		Remaining	Aggregate
	Number of	Exercise		Contractual	Intrinsic
	Options	Price		Term	Value
	(in thousands)	per Share		(Years)	(in thousands)
Outstanding, January 1, 2022	226	$	12.78
Granted	—		—
Exercised	(75)		9.06
Canceled	(3)		13.57
Expired	—		—
Outstanding, March 31, 2022	148	$	14.64	4.19	$	1,954
Vested and expected to vest, March 31, 2022	146	$	14.63	4.15	$	1,936
Exercisable, March 31, 2022	121	$	14.54	3.45	$	1,612

The aggregate intrinsic value in the table above represents the total intrinsic value based on the Company’s closing stock price of $27.87 per share as of March 31, 2022. The total intrinsic value of options exercised was $1.3 million during the three months ended March 31, 2022.

As of March 31, 2022, there was $0.1 million of total unrecognized compensation cost, net of forfeiture, related to unvested stock options, which is expected to be recognized over a weighted average period of 1.5 years. The total fair value of shares vested was immaterial during the three months ended March 31, 2022.

Nonvested restricted stock unit activity during the three months ended March 31, 2022, was as follows:

		Weighted
		Average Grant
	Shares	Date Fair Value
	(in thousands)	Per Share
Nonvested, January 1, 2022	1,872	$	18.24
Granted	275	$	27.90
Vested	(344)	$	19.73
Forfeited	(30)	$	18.43
Nonvested, March 31, 2022	1,773	$	19.45

As of March 31, 2022, there was $27.2 million of total unrecognized compensation cost related to restricted stock units. That cost is expected to be recognized over a weighted average period of 2.4 years. Restricted stock units do not have rights to dividends prior to vesting.

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Note 8 - INCOME TAXES

3 Months Ended

Mar. 31, 2022

INCOME TAXES

INCOME TAXES

8. INCOME TAXES

Income tax expense increased $0.2 million for the three months ended March 31, 2022, to a $1.2 million income tax expense as compared to an income tax expense of $1.0 million for the three months ended March 31, 2021. The Company’s effective tax rate expense was (40%) and (14%) for the three months ended March 31, 2022 and 2021, respectively. The Company’s effective tax rate expense increased in the three months ended March 31, 2022, as compared to the same period in 2021, primarily due to increases in foreign withholding taxes and changes in the geographic mix of worldwide income, which is subject to taxation at different statutory tax rates.

The Company’s total amount of unrecognized tax benefits, excluding interest and penalties, as of March 31, 2022, was $15.0 million, of which $2.0 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, 2021, was $14.7 million, of which $1.9 million, if recognized, would affect the Company’s effective tax rate. As of March 31, 2022, the Company has recorded unrecognized tax benefits of $2.6 million, including interest and penalties of $0.7 million, as long-term taxes payable in its Condensed Consolidated Balance Sheet. The remaining $13.1 million has been recorded net of the Company’s DTAs, which is subject to a full valuation allowance.

The valuation allowance was approximately $51.6 million as of March 31, 2022 and December 31, 2021, which was related to U.S. net federal and state DTAs. The worldwide net deferred tax assets balance as of March 31, 2022 and December 31, 2021 were not significant.

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. For U.S. federal and California income tax purposes, the statute of limitations currently remains open for the tax years ending 2018 to present and 2017 to present, respectively. In addition, due to NOL carryback claims, the tax years 2013 through 2015 may be subject to federal examination and all of the net operating loss and research and development credit carryforwards that may be utilized in future years may be subject to federal and state examination. The Company is not subject to income tax examinations in any other of its major foreign subsidiaries’ jurisdictions.

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Note 9 - NET LOSS PER SHARE

3 Months Ended

Mar. 31, 2022

NET LOSS PER SHARE

NET LOSS PER SHARE

9. NET LOSS PER SHARE

Basic net loss per share is computed by dividing net loss by weighted average number of common shares outstanding for the period (excluding outstanding stock options and shares subject to repurchase). Diluted net 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. The following is a reconciliation of the numerators and denominators used in computing basic and diluted net loss per share (in thousands except per share amount):

	Three Months Ended March 31,
	2022		2021
Numerator:
Net loss	$	(4,150)	$	(7,597)
Denominator:
Basic weighted-average shares outstanding		37,606		36,974
Effect of dilutive options and restricted stock units		—		—
Diluted weighted-average shares outstanding		37,606		36,974
Net loss per share, basic and diluted	$	(0.11)	$	(0.21)

For the three months ended March 31, 2022 and 2021, because the Company was in a loss position, basic net loss per share is the same as diluted net loss per share as the inclusion of the potential common shares would have been anti-dilutive.

The following table sets forth potential shares of common stock that were not included in the diluted net loss per share calculation above because to do so would be anti-dilutive for the periods indicated (in thousands):

	Three Months Ended March 31,
	2022	2021
Outstanding options	102	224
Nonvested restricted stock units	905	1,107
Employee Stock Purchase Plan	94	10
Total	1,101	1,341

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Note 10 - CUSTOMER AND GEOGRAPHIC INFORMATION

3 Months Ended

Mar. 31, 2022

CUSTOMER AND GEOGRAPHIC INFORMATION

CUSTOMER AND GEOGRAPHIC INFORMATION

10. CUSTOMER AND GEOGRAPHIC INFORMATION

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

The Company’s chief operating decision maker, the chief executive officer, reviews discrete financial information presented on a consolidated basis for purposes of regularly making operating decisions, allocation of resources, and assessing financial performance. Accordingly, the Company considers itself to be in one operating and reporting segment, specifically the provision of services for differentiated data and analytics solutions to the semiconductor and electronics industries.

The Company had revenues from individual customers that are approximately 10% or more of the Company’s consolidated total revenues as follows:

	Three Months Ended March 31,
Customer	2022		2021
A	*	%	13	%
D	33	%	*	%
E	*	%	11	%

* represents less than 10%

Gross accounts receivable balances (including amounts that are unbilled) from individual customers that are approximately 10% or more of the Company’s gross accounts receivable balance as follows:

	March 31,		December 31,
Customer	2022		2021
C	*	%	15	%
D	43	%	29	%

* represents less than 10%

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

	Three Months Ended March 31,
	2022				2021
			Percentage				Percentage
	Revenues		of Revenues		Revenues		of Revenues
United States	$	17,491	52	%	$	8,556	35	%
China		4,120	12			1,739	7
Japan		2,607	8			3,578	15
Rest of the world		9,280	28			10,327	43
Total revenue	$	33,498	100	%	$	24,200	100	%

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

	March 31,		December 31,
	2022		2021
United States (1)	$	40,602	$	39,158
Rest of the world		721		1,545
Total long-lived assets, net	$	41,323	$	40,703

(1) Includes assets deployed at customer sites which could be outside the U.S.

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Note 11 - FAIR VALUE MEASUREMENTS

3 Months Ended

Mar. 31, 2022

FAIR VALUE MEASUREMENTS

FAIR VALUE MEASUREMENTS

11. 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, 2022, and December 31, 2021, and the basis for those measurements (in thousands):

	Fair Value Measurements Using
			Quoted
			Prices in
			Active		Significant
			Markets for		Other
			Identical		Observable		Significant
	March 31,		Assets		Inputs		Unobservable
Assets	2022		(Level 1)		(Level 2)		Inputs (Level 3)
Cash equivalents
Money market mutual funds	$	19,017	$	19,017	$	—	$	—
Short-term investments (available-for-sale debt securities)
U.S. Government securities (1)		98,443		98,443		—		—
Total	$	117,460	$	117,460	$	—	$	—

	Fair Value Measurements Using
			Quoted
			Prices in
			Active		Significant
			Markets for		Other		Significant
			Identical		Observable		Unobservable
	December 31,		Assets		Inputs		Inputs
Assets	2021		(Level 1)		(Level 2)		(Level 3)
Cash equivalents
Money market mutual funds	$	12,474	$	12,474	$	—	$	—
Short-term investments (available-for-sale debt securities)
U.S. Government securities (1)		112,542		112,542		—		—
Total	$	125,016	$	125,016	$	—	$	—

(1) As of March 31, 2022, and December 31, 2021, the amortized cost of the Company’s investments in U.S Government Securities approximated their fair value due to their short-term maturities, and there have been no events or changes

in circumstances that would have had a significant effect on the fair value of these securities in the periods presented. There was no material realized or unrealized gains or losses, either individually or in the aggregate.

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Note 12 - COMMITMENTS AND CONTINGENCIES

3 Months Ended

Mar. 31, 2022

COMMITMENTS AND CONTINGENCIES

COMMITMENTS AND CONTINGENCIES

12. COMMITMENTS AND CONTINGENCIES

Strategic Partnership with Advantest — See Note 3, Strategic Partnership Agreement with Advantest And Related Party Transactions, for the discussion about the Company’s commitments under the strategic partnership with Advantest.

Operating Leases — Refer to Note 5, Leases, for the discussion about the Company’s lease commitments. The Company entered into lease agreements with total future minimum lease payments of $0.7 million over the next three years that will commence subsequent to March 31, 2022.

Indemnifications — The Company generally provides a warranty to its customers that its software will perform substantially in accordance with documented specifications typically for a period of 90 days following initial delivery of its products. The Company also indemnifies certain customers from third-party claims of intellectual property infringement relating to the use of its products. Historically, costs related to these guarantees have not been significant. The Company is unable to estimate the maximum potential impact of these guarantees on its future results of operations.

Purchase Obligations — The Company has purchase obligations with certain suppliers for the purchase of goods and services entered in the ordinary course of business. As of March 31, 2022, total outstanding purchase obligations were $12.8 million, the majority of which is due within the next 12 months.

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

In addition, the Bylaws of the Company provide that the Company is required to indemnify its officers and directors even when indemnification would otherwise be discretionary, and the Company is required to advance expenses to its officers and directors as incurred in connection with proceedings against them for which they may be indemnified. The Company has entered into indemnification agreements with its officers and directors containing provisions that are in some respects broader than the specific indemnification provisions contained in the Delaware general corporation law. The indemnification agreements require the Company to indemnify its officers and directors against liabilities that may arise by reason of their status or service as officers and directors other than for liabilities arising from willful misconduct of a culpable nature, to advance their expenses incurred as a result of any proceeding against them as to which they could be indemnified, and to obtain directors’ and officers’ insurance if available on reasonable terms. The Company has obtained directors’ and officers’ liability insurance in amounts comparable to other companies of the Company’s size and in the Company’s industry. Since a maximum obligation of the Company is not explicitly stated in the Company’s Bylaws or in its indemnification agreements and will depend on the facts and circumstances that arise out of any future claims, the overall maximum amount of the obligations cannot be reasonably estimated.

Legal Proceedings — 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. As of March 31, 2022, except as disclosed below, the Company was not party to any material legal proceedings, thus no loss was probable and no amount was accrued.

On May 6, 2020, the Company initiated an arbitration proceeding with the Hong Kong International Arbitration Center against SMIC New Technology Research & Development (Shanghai) Corporation (“SMIC”) due to SMIC’s failure to pay fees due to PDF under a series of contracts. The Company seeks to recover the unpaid fees, a declaration requiring SMIC to pay fees under the contracts in the future, and costs associated with bringing the arbitration proceeding. SMIC denies liability and the arbitration is on-going.

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Note 13 - SUBSEQUENT EVENTS

3 Months Ended

Mar. 31, 2022

SUBSEQUENT EVENTS

SUBSEQUENT EVENTS

13. SUBSEQUENT EVENTS

Refer to Note 7, Employee Benefits Plans, for the discussion about the amendment to the 2011 Stock Incentive Plan.

Refer to Note 6, Stockholder’s Equity, for the discussion about the adoption of the 2022 Stock Repurchase Program.

On April 12, 2022, the Company repurchased approximately 715,000 shares of its common stock in a privately negotiated transaction for $16.7 million under the 2022 Stock Repurchase Program. The stock repurchase was made in a block trade in compliance with Rule 10b-18 under the Securities Exchange Act of 1934, as amended (the Exchange Act).

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Note 1 - BASIS OF PRESENTATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)

3 Months Ended

Mar. 31, 2022

BASIS OF PRESENTATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

Basis of Accounting, Policy [Policy Text Block]

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, 2021.

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

The condensed consolidated balance sheet at December 31, 2021, 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, Policy [Policy Text Block]

Use of Estimates

The preparation of financial statements in conformity with generally accepted accounting principles in the United States (“U.S. GAAP”) requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Significant estimates in these financial statements include revenue recognition, the estimated useful lives of property and equipment and intangible assets, assumptions made in analysis of allowance for doubtful accounts, fair values of assets acquired and liabilities assumed in business combinations, impairment of goodwill and long-lived assets, valuation for deferred tax assets, and accounting for lease obligations, stock-based compensation expense, and income tax uncertainties and contingencies. Actual results could differ from those estimates and may result in material effects on the Company’s operating results and financial position.

The global COVID-19 pandemic has impacted the operations and purchasing decisions of companies worldwide. As of the date of issuance of the condensed consolidated financial statements, the Company is not aware of any specific event or circumstance relating to COVID-19 that would require updates to the Company’s estimates and judgments or revisions to the carrying value of its assets or liabilities. These estimates may change, as new events occur and additional information is obtained, and are recognized in the condensed consolidated financial statements as soon as they become known. Actual results could differ from those estimates and any such differences may be material to the financial statements.

Revenue from Contract with Customer [Policy Text Block]

The Company recognizes revenue in accordance with FASB ASC Topic 606, Revenue from Contracts with Customers, and its related amendments (collectively known as “ASC 606”). ASC 606 outlines a single comprehensive model to use in accounting for revenue arising from contracts with customers. Revenue is recognized when control of products or services is transferred to customers, in an amount that reflects the consideration the Company expects to be entitled to in exchange for those promised products or services.

The Company determines revenue recognition through the following five steps:

● Identification of the contract, or contracts, with a customer

● Identification of the performance obligations in the contract

● Determination of the transaction price

● Allocation of the transaction price to the performance obligations in the contract

● Recognition of revenue when, or as, performance obligations are satisfied

The Company accounts for a contract when it has approval and commitment from both parties, the rights of the parties are identified, payment terms are identified, the contract has commercial substance, and collectability of consideration is probable.

Contracts with multiple performance obligations

The Company enters into contracts that can include various combinations of licenses, products and services, some of which are distinct and are accounted for as separate performance obligations. For contracts with multiple performance obligations, the Company allocates the transaction price of the contract to each performance obligation on a relative basis using the standalone selling price (“SSP”).

Accounts Receivable [Policy Text Block]

Accounts receivable include amounts that are unbilled at the end of the period that are expected to be billed and collected within a 12-month period.

Share-based Payment Arrangement [Policy Text Block]

In July 2001, the Company’s stockholders initially approved the 2001 Employee Stock Purchase Plan, which was subsequently amended and restated in 2010 (as amended, the “2010 Purchase Plan”) to extend the term of the plan through May 17, 2020. Under the 2010 Purchase Plan, eligible employees could contribute up to 10% of their compensation, as defined in the 2010 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 2010 Purchase Plan provided for twenty-four-month offering periods with four six-month purchase periods in each offering period. The 2010 Purchase Plan expired on May 17, 2020. Existing offering periods under the 2010 Plan continued through the applicable expiration date and the final offering period expired on January 31, 2022. On June 15, 2021, the Company’s stockholders approved the 2021 Employee Stock Purchase Plan, which has a ten-year term (the “2021 Purchase Plan”). The terms of 2021 Purchase Plan are substantially similar to those of the 2010 Purchase Plan. A twenty-four-month offering period under the 2021 Purchase Plan commenced on August 1, 2021.

Earnings Per Share, Policy [Policy Text Block]

Basic net loss per share is computed by dividing net loss by weighted average number of common shares outstanding for the period (excluding outstanding stock options and shares subject to repurchase). Diluted net 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.

Segment Reporting, Policy [Policy Text Block]

The Company’s chief operating decision maker, the chief executive officer, reviews discrete financial information presented on a consolidated basis for purposes of regularly making operating decisions, allocation of resources, and assessing financial performance. Accordingly, the Company considers itself to be in one operating and reporting segment, specifically the provision of services for differentiated data and analytics solutions to the semiconductor and electronics industries.

Fair Value Measurement, Policy [Policy Text Block]

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.

New Accounting Pronouncements, Policy [Policy Text Block]

Recent Accounting Standards

Accounting Standards Adopted

Management has reviewed recently issued accounting pronouncements and has determined there are not any that would have a material impact on the condensed consolidated financial statements.

Accounting Standards Not Yet Adopted

In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments – Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments (ASU 2016-13), which requires measurement and recognition of expected credit losses for financial assets held at the reporting date based on internal information, external information, or a combination of both relating to past events, current conditions, and reasonable and supportable forecasts. ASU No. 2016-13 replaces the existing incurred loss impairment model with a forward-looking expected credit loss model, which will result in earlier recognition of credit losses. Subsequent to the issuance of ASU No. 2016-13, the FASB issued ASU No. 2018-19, Codification Improvements to Topic 326, Financial Instruments – Credit Losses, ASU No. 2019-04, Codification Improvements to Topic 326, Financial Instruments – Credit Losses, Topic 815, Derivatives and Hedging, and Topic 825, Financial Instrument, ASU No. 2019-05, Financial Instruments – Credit Losses (Topic 326) Targeted Transition Relief, ASU No. 2016-13, ASU No. 2019-10 Financial Instruments-Credit Losses (Topic 326), Derivatives and Hedging (Topic 815), and Leases (Topic 842), and ASU No. 2019-11 Codification Improvements to Topic 326, Financial Instruments-Credit Losses. The subsequent ASUs do not change the core principle of the guidance in ASU No. 2016-13. Instead, these amendments are intended to clarify and improve operability of certain topics included within ASU No. 2016-13.

Additionally, ASU No. 2019-10 defers the effective date for the adoption of the new standard on credit losses for public filers that are considered small reporting companies (“SRC”) as defined by the SEC to fiscal years beginning after December 15, 2022, including interim periods within those fiscal years, which will be fiscal 2023 for the Company if it continues to be classified as an SRC. In February 2020, the FASB issued ASU 2020-02, which provides guidance regarding methodologies, documentation, and internal controls related to expected credit losses. The subsequent amendments will have the same effective date and transition requirements as ASU No. 2016-13. Early adoption is permitted. Topic 326 requires a modified retrospective approach by recording a cumulative-effect adjustment to retained earnings as of the beginning of the period of adoption. While the Company is currently evaluating the impact of Topic 326, the Company does not expect the adoption of this ASU to have a material impact on its condensed consolidated financial statements or the related disclosure.

In August 2020, the FASB issued ASU No. 2020-06, Debt – Debt with Conversion and Other Options (Subtopic 470-20) and Derivatives and Hedging – Contracts in Entity’s Own Equity (Subtopic 815-20): Accounting for Convertible Instruments and Contracts in an Entity’s Own Equity, which is intended to simplify the accounting for certain financial instruments with characteristics of liabilities and equity, including convertible instruments and contracts on an entity’s own equity. The guidance allows for either full retrospective adoption or modified retrospective adoption. Additionally, the ASU will require entities to use the “if-converted” method when calculating diluted earnings per share for convertible instruments. The ASU will be effective for annual reporting periods beginning after December 15, 2023 for SRCs and interim periods within those annual periods. Early adoption is permitted. The Company does not anticipate that the adoption of this ASU will have a significant impact on its condensed consolidated financial statements or the related disclosures.

Management has reviewed other recently issued accounting pronouncements issued or proposed by the FASB, and does not believe any of these accounting pronouncements has had or will have a material impact on the condensed consolidated financial statements.

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Note 2 - REVENUE FROM CONTRACTS WITH CUSTOMERS (Tables)

3 Months Ended

Mar. 31, 2022

Notes Tables

Disaggregation of Revenue [Table Text Block]

The Company’s performance obligations are satisfied either over time or at a point-in-time. The following table represents a disaggregation of revenue by timing of revenue:

	Three Months Ended March 31,
	2022		2021
Over time	70	%	50	%
Point-in-time	30	%	50	%
Total	100	%	100	%

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Note 4 - BALANCE SHEET COMPONENTS (Tables)

3 Months Ended

Mar. 31, 2022

Notes Tables

Property, Plant and Equipment [Table Text Block]

Property and equipment, net consist of the following (in thousands):

	March 31,		December 31,
	2022		2021
Computer equipment	$	11,887	$	11,924
Software		5,411		5,419
Furniture, fixtures and equipment		2,503		2,506
Leasehold improvements		6,266		6,272
Laboratory and other equipment		4,171		3,981
Test equipment		28,060		24,452
Construction-in-progress		21,263		22,158
		79,561		76,712
Less: accumulated depreciation and amortization		(42,717)		(41,417)
Total	$	36,844	$	35,295

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

Intangible assets, net, consisted of the following (in thousands):

		March 31, 2022						December 31, 2021
	Amortization	Gross				Net		Gross				Net
	Period	Carrying		Accumulated		Carrying		Carrying		Accumulated		Carrying
	(Years)	Amount		Amortization		Amount		Amount		Amortization		Amount
Acquired identifiable intangibles:
Customer relationships	1-10	$	9,407	$	(6,202)	$	3,205	$	9,407	$	(6,041)	$	3,366
Developed technology	4-9		33,635		(17,848)		15,787		33,635		(17,250)		16,385
Tradename and trademarks	2-10		1,598		(839)		759		1,598		(812)		786
Patent	7-10		1,800		(1,650)		150		1,800		(1,640)		160
Noncompetition agreements	3		848		(377)		471		848		(306)		542
Total		$	47,288	$	(26,916)	$	20,372	$	47,288	$	(26,049)	$	21,239

Finite-lived Intangible Assets Amortization Expense [Table Text Block]

The weighted average amortization period for acquired identifiable intangible assets was 6.6 years as of March 31, 2022. The following table summarizes intangible assets amortization expense in the Condensed Consolidated Statements of Comprehensive Loss (in thousands):

	Three Months Ended March 31,
	2022		2021
Amortization of acquired technology included under Costs of Revenues	$	553	$	535
Amortization of acquired intangible assets presented separately under Costs and Expenses		314		314
Total amortization of acquired intangible assets	$	867	$	849

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

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

Year Ending December 31,	Amount
2022 (remaining nine months)	$	2,601
2023		3,444
2024		3,046
2025		2,882
2026		2,712
2027 and thereafter		5,687
Total future amortization expense	$	20,372

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Note 5 - LEASES (Tables)

3 Months Ended

Mar. 31, 2022

Notes Tables

Lease, Cost [Table Text Block]

In the first quarter of 2022, the Company early terminated an office lease contract. The termination of this lease reduces the Company’s operating lease right-of-use assets and lease liabilities by approximately $0.5 million and $0.6 million, respectively. The gain from the lease termination of approximately $0.1 million was recorded under selling, general and administrative expense in the Condensed Consolidated Statement of Comprehensive Loss for the three months ended March 31, 2022.

Lease expense was comprised of the following (in thousands):

	Three Months Ended March 31,
	2022		2021
Operating lease expense (1)	$	345	$	485
Short-term lease and variable lease expense (2)		283		174
Total lease expense	$	628	$	659

(1) Net of gain recognized upon lease termination of $0.1 million in three month ended March 31, 2022.

(2) Leases with an initial term of 12 months or less are not recorded on the Condensed Consolidated Balance Sheets, and the Company recognizes lease expense for these leases on a straight-line basis over the lease term. Variable lease expense for the periods presented primarily included common area maintenance charges.

Supplemental balance sheets information related to operating leases was as follows:

	March 31,			December 31,
	2022			2021
Weighted average remaining lease term under operating ROU leases (in years)		6.0			5.7
Weighted average discount rate for operating lease liabilities		5.25	%		5.25	%

Lessee, Operating Lease, Liability, Maturity [Table Text Block]

Maturities of operating lease liabilities as of March 31, 2022, were as follows (in thousands):

Year Ending December 31,	Amount (1)
2022 (remaining nine months)	$	960
2023		1,137
2024		1,070
2025		1,086
2026		1,053
2027 and thereafter		1,650
Total future minimum lease payments	$	6,956
Less: Interest (2)		(990)
Present value of future minimum lease payments under operating lease liabilities (3)	$	5,966

(1) As of March 31, 2022, the total operating lease liability includes approximately $1.1 million related to an option to extend a lease term that is reasonably certain to be exercised.

(2) Calculated using incremental borrowing interest rate for each lease.

(3) Includes the current portion of operating lease liabilities of $1.2 million as of March 31, 2022.

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Note 7 - EMPLOYEE BENEFIT PLANS (Tables)

3 Months Ended

Mar. 31, 2022

Notes Tables

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

	2021 Purchase Plan			2010 Purchase Plan
	Three Months Ended March 31,			Three Months Ended March 31,
	2022			2021
Expected life (in years)		1.25			1.25
Volatility		48.90	%		34.25	%
Risk-free interest rate		0.86	%		1.43	%
Expected dividend		—			—
Weighted average fair value of purchase rights granted during the period	$	10.76		$	4.83

Share-based Payment Arrangement, Expensed and Capitalized, Amount [Table Text Block]

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

	Three Months Ended March 31,
	2022		2021
Costs of revenues	$	728	$	652
Research and development		3,168		1,588
Selling, general and administrative		1,657		1,129
Stock-based compensation expenses	$	5,553	$	3,369

Share-based Payment Arrangement, Option, Activity [Table Text Block]

	Outstanding Options
				Weighted
		Weighted		Average
		Average		Remaining	Aggregate
	Number of	Exercise		Contractual	Intrinsic
	Options	Price		Term	Value
	(in thousands)	per Share		(Years)	(in thousands)
Outstanding, January 1, 2022	226	$	12.78
Granted	—		—
Exercised	(75)		9.06
Canceled	(3)		13.57
Expired	—		—
Outstanding, March 31, 2022	148	$	14.64	4.19	$	1,954
Vested and expected to vest, March 31, 2022	146	$	14.63	4.15	$	1,936
Exercisable, March 31, 2022	121	$	14.54	3.45	$	1,612

Share-based Payment Arrangement, Restricted Stock Unit, Activity [Table Text Block]

		Weighted
		Average Grant
	Shares	Date Fair Value
	(in thousands)	Per Share
Nonvested, January 1, 2022	1,872	$	18.24
Granted	275	$	27.90
Vested	(344)	$	19.73
Forfeited	(30)	$	18.43
Nonvested, March 31, 2022	1,773	$	19.45

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Note 9 - NET LOSS PER SHARE (Tables)

3 Months Ended

Mar. 31, 2022

Notes Tables

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

Basic net loss per share is computed by dividing net loss by weighted average number of common shares outstanding for the period (excluding outstanding stock options and shares subject to repurchase). Diluted net 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. The following is a reconciliation of the numerators and denominators used in computing basic and diluted net loss per share (in thousands except per share amount):

	Three Months Ended March 31,
	2022		2021
Numerator:
Net loss	$	(4,150)	$	(7,597)
Denominator:
Basic weighted-average shares outstanding		37,606		36,974
Effect of dilutive options and restricted stock units		—		—
Diluted weighted-average shares outstanding		37,606		36,974
Net loss per share, basic and diluted	$	(0.11)	$	(0.21)

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

The following table sets forth potential shares of common stock that were not included in the diluted net loss per share calculation above because to do so would be anti-dilutive for the periods indicated (in thousands):

	Three Months Ended March 31,
	2022	2021
Outstanding options	102	224
Nonvested restricted stock units	905	1,107
Employee Stock Purchase Plan	94	10
Total	1,101	1,341

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Note 10 - CUSTOMER AND GEOGRAPHIC INFORMATION (Tables)

3 Months Ended

Mar. 31, 2022

Notes Tables

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

The Company had revenues from individual customers that are approximately 10% or more of the Company’s consolidated total revenues as follows:

	Three Months Ended March 31,
Customer	2022		2021
A	*	%	13	%
D	33	%	*	%
E	*	%	11	%

* represents less than 10%

Gross accounts receivable balances (including amounts that are unbilled) from individual customers that are approximately 10% or more of the Company’s gross accounts receivable balance as follows:

	March 31,		December 31,
Customer	2022		2021
C	*	%	15	%
D	43	%	29	%

* represents less than 10%

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

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

	Three Months Ended March 31,
	2022				2021
			Percentage				Percentage
	Revenues		of Revenues		Revenues		of Revenues
United States	$	17,491	52	%	$	8,556	35	%
China		4,120	12			1,739	7
Japan		2,607	8			3,578	15
Rest of the world		9,280	28			10,327	43
Total revenue	$	33,498	100	%	$	24,200	100	%

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

	March 31,		December 31,
	2022		2021
United States (1)	$	40,602	$	39,158
Rest of the world		721		1,545
Total long-lived assets, net	$	41,323	$	40,703

(1) Includes assets deployed at customer sites which could be outside the U.S.

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Note 11 - FAIR VALUE MEASUREMENTS (Tables)

3 Months Ended

Mar. 31, 2022

Notes Tables

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

The following table represents the Company’s assets measured at fair value on a recurring basis as of March 31, 2022, and December 31, 2021, and the basis for those measurements (in thousands):

	Fair Value Measurements Using
			Quoted
			Prices in
			Active		Significant
			Markets for		Other
			Identical		Observable		Significant
	March 31,		Assets		Inputs		Unobservable
Assets	2022		(Level 1)		(Level 2)		Inputs (Level 3)
Cash equivalents
Money market mutual funds	$	19,017	$	19,017	$	—	$	—
Short-term investments (available-for-sale debt securities)
U.S. Government securities (1)		98,443		98,443		—		—
Total	$	117,460	$	117,460	$	—	$	—

	Fair Value Measurements Using
			Quoted
			Prices in
			Active		Significant
			Markets for		Other		Significant
			Identical		Observable		Unobservable
	December 31,		Assets		Inputs		Inputs
Assets	2021		(Level 1)		(Level 2)		(Level 3)
Cash equivalents
Money market mutual funds	$	12,474	$	12,474	$	—	$	—
Short-term investments (available-for-sale debt securities)
U.S. Government securities (1)		112,542		112,542		—		—
Total	$	125,016	$	125,016	$	—	$	—

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Note 2 - REVENUE FROM CONTRACTS WITH CUSTOMERS - 1 (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2022 USD ($) item	Mar. 31, 2021 USD ($)	Dec. 31, 2021 USD ($)
Number of revenue sources | item	2
Contract with Customer, Asset, after Allowance for Credit Loss, Current, Total	$ 400		$ 400
Capitalized Contract Cost, Impairment Loss	0	$ 0
Contract with Customer, Liability, Noncurrent	2,000		2,400
Contract with Customer, Liability, Revenue Recognized	6,900	6,300
Revenue, Remaining Performance Obligation, Amount	196,800
Contract with Customer, Performance Obligation Satisfied in Previous Period	200	300
Capitalized Contract Cost, Amortization	173	$ 165
Prepaid Expenses and Other Current Assets [Member]
Capitalized Contract Cost, Net, Total	900		600
Other Noncurrent Assets [Member]
Capitalized Contract Cost, Net, Total	$ 2,100		$ 2,100
Geographic Concentration Risk [Member] | Revenue Benchmark [Member]
Concentration Risk, Percentage	100.00%	100.00%
Geographic Concentration Risk [Member] | Revenue Benchmark [Member] | Non-US [Member]
Concentration Risk, Percentage	48.00%	65.00%

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Note 2 - REVENUE FROM CONTRACTS WITH CUSTOMERS - Narrative 2 (Details) - Software License and Related Services Agreement [Member] - Advantest America, Inc. [Member]	Mar. 31, 2022
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-04-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period (Year)	2 years
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-04-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period (Year)	3 years

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Note 2 - REVENUE FROM CONTRACTS WITH CUSTOMERS - Disaggregation of Revenue (Details)	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Percent of revenues	100.00%	100.00%
Transferred over Time [Member]
Percent of revenues	70.00%	50.00%
Transferred at Point in Time [Member]
Percent of revenues	30.00%	50.00%

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Note 3 - STRATEGIC PARTNERSHIP AGREEMENT WITH ADVANTEST AND RELATED PARTY TRANSACTIONS (Details) - USD ($) $ in Thousands		3 Months Ended
	Jul. 29, 2020	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
Revenue from Contract with Customer, Including Assessed Tax		$ 33,498	$ 24,200
Strategic Partnership for Joint Development and Sales Technology Solutions [Member]
Stock Issued During Period, Shares, New Issues (in shares)	3,306,924
Proceeds from Issuance of Common Stock	$ 65,200
Amendment #1 to Software License & Related Services Agreement [Member]
Revenue from Contract with Customer, Including Assessed Tax		2,600	$ 2,600
Related Party Transaction, Due from (to) Related Party, Total		0		$ 0
Contract with Customer, Liability, Total		$ 4,200		$ 6,800

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Note 4 - BALANCE SHEET COMPONENTS - Other (Details) - USD ($)	3 Months Ended
	Mar. 31, 2022	Dec. 31, 2021	Mar. 31, 2021
Unbilled Receivables, Current	$ 10,800,000	$ 11,800,000
Unbilled Receivables, Not Expected to be Billed and Collected in Next Twelve Months	1,300,000	1,300,000
Depreciation, Depletion and Amortization, Nonproduction, Total	1,400,000		$ 1,700,000
Impairment of Intangible Assets, Finite-lived	0		0
Goodwill	14,123,000	14,123,000
Impairment of goodwill	0		0
Amortization of Intangible Assets, Total	$ 867,000		849,000
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life (Year)	6 years 7 months 6 days
Write-down in value of property and equipment		3,200,000
Cost of Sales [Member]
Amortization of Intangible Assets, Total	$ 553,000		535,000
Costs and Expenses [Member]
Amortization of Intangible Assets, Total	314,000		$ 314,000
DFI Test Equipment [Member]
Construction in Progress, Gross	$ 18,500,000	$ 20,000,000.0

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Note 4 - BALANCE SHEET COMPONENTS - Property and Equipment (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Property and equipment, gross	$ 79,561	$ 76,712
Less: accumulated depreciation and amortization	(42,717)	(41,417)
Total	36,844	35,295
Computer Equipment [Member]
Property and equipment, gross	11,887	11,924
Software and Software Development Costs [Member]
Property and equipment, gross	5,411	5,419
Furniture and Fixtures [Member]
Property and equipment, gross	2,503	2,506
Leasehold Improvements [Member]
Property and equipment, gross	6,266	6,272
Laboratory and Test Equipment [Member]
Property and equipment, gross	4,171	3,981
Test Equipment [Member]
Property and equipment, gross	28,060	24,452
Construction in Progress [Member]
Property and equipment, gross	$ 21,263	$ 22,158

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Note 4 - BALANCE SHEET COMPONENTS - Intangible Assets (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Dec. 31, 2021
Amortization Period (Year)	6 years 7 months 6 days
Gross Carrying Amount	$ 47,288	$ 47,288
Accumulated Amortization	(26,916)	(26,049)
Net Carrying Amount	20,372
Net Carrying Amount, Total	20,372	21,239
Customer Relationships [Member]
Gross Carrying Amount	9,407	9,407
Accumulated Amortization	(6,202)	(6,041)
Net Carrying Amount	$ 3,205	3,366
Customer Relationships [Member] | Minimum [Member]
Amortization Period (Year)	1 year
Customer Relationships [Member] | Maximum [Member]
Amortization Period (Year)	10 years
Developed Technology Rights [Member]
Gross Carrying Amount	$ 33,635	33,635
Accumulated Amortization	(17,848)	(17,250)
Net Carrying Amount	$ 15,787	16,385
Developed Technology Rights [Member] | Minimum [Member]
Amortization Period (Year)	4 years
Developed Technology Rights [Member] | Maximum [Member]
Amortization Period (Year)	9 years
Trademarks and Trade Names [Member]
Gross Carrying Amount	$ 1,598	1,598
Accumulated Amortization	(839)	(812)
Net Carrying Amount	$ 759	786
Trademarks and Trade Names [Member] | Minimum [Member]
Amortization Period (Year)	2 years
Trademarks and Trade Names [Member] | Maximum [Member]
Amortization Period (Year)	10 years
Patents [Member]
Gross Carrying Amount	$ 1,800	1,800
Accumulated Amortization	(1,650)	(1,640)
Net Carrying Amount	$ 150	160
Patents [Member] | Minimum [Member]
Amortization Period (Year)	7 years
Patents [Member] | Maximum [Member]
Amortization Period (Year)	10 years
Noncompete Agreements [Member]
Amortization Period (Year)	3 years
Gross Carrying Amount	$ 848	848
Accumulated Amortization	(377)	(306)
Net Carrying Amount	$ 471	$ 542

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Note 4 - BALANCE SHEET COMPONENTS - Annual Amortization of Identifiable Intangible Assets (Details) $ in Thousands	Mar. 31, 2022 USD ($)
BALANCE SHEET COMPONENTS
2022 (remaining nine months)	$ 2,601
2023	3,444
2024	3,046
2025	2,882
2026	2,712
2027 and thereafter	5,687
Net Carrying Amount	$ 20,372

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Note 5 - LEASES - Other (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2022 USD ($) lease	Dec. 31, 2021 USD ($) lease
LEASES
Number of finance leases | lease	0	0
Operating Lease, Liability, Amount Related to Extension of Lease Term	$ 1,100
Operating Lease, Liability, Current	1,225	$ 1,758
Operating lease right of use assets decrease from early lease termination	500
Operating lease liability decrease from early lease termination	600
Lease termination gain	$ 100

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Note 5 - LEASES - Lease Cost (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
LEASES
Operating lease expense	$ 345	$ 485
Short-term lease and variable lease expense	283	174
Total lease expense	628	$ 659
Lease termination gain	$ 100
Weighted average remaining lease term under operating ROU leases (in years) (Year)	6 years		5 years 8 months 12 days
Weighted average discount rate for operating lease liabilities	5.25%		5.25%

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Note 5 - LEASES - Maturity of Operating Lease Liabilities (Details) $ in Thousands	Mar. 31, 2022 USD ($)
LEASES
2022 (remaining nine months)	$ 960
2023	1,137
2024	1,070
2025	1,086
2026	1,053
2027 and thereafter	1,650
Total future minimum lease payments	6,956
Less: Interest (2)	(990)
Present value of future minimum lease payments under operating lease liabilities (3)	$ 5,966

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Note 6 - STOCKHOLDERS EQUITY (Details) - USD ($) $ / shares in Units, $ in Thousands			3 Months Ended		22 Months Ended
	Apr. 11, 2022	Jun. 04, 2020	Mar. 31, 2022	Mar. 31, 2021	Mar. 31, 2022
Treasury Stock, Value, Acquired, Cost Method			$ 5,778	$ 4,523
The 2020 Stock Repurchase Program [Member]
Treasury Stock, Shares, Acquired (in shares)			218,858	251,000	470,000
Treasury Stock Acquired, Average Cost Per Share (in dollars per share)			$ 26.40	$ 18.01	$ 21.91
Treasury Stock, Value, Acquired, Cost Method			$ 5,800	$ 4,500	$ 10,300
Stock Repurchase Program, Authorized Amount		$ 25,000
Stock Repurchase Program, Period in Force (Year)		2 years
Stock Repurchase Program 2022 [Member]
Stock Repurchase Program, Authorized Amount	$ 35,000
Stock Repurchase Program, Period in Force (Year)	2 years

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Note 7 - EMPLOYEE BENEFIT PLANS - Other (Details) $ / shares in Units, $ in Millions					1 Months Ended	3 Months Ended		125 Months Ended
	Apr. 26, 2022 shares	Jun. 15, 2021	Nov. 16, 2011 shares	Jul. 31, 2001	Jul. 31, 2001 item	Mar. 31, 2022 USD ($) $ / shares shares	Mar. 31, 2021 $ / shares shares	Mar. 31, 2022 USD ($) $ / shares shares	Dec. 31, 2021 shares	Dec. 31, 2001 shares
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period (Year)						4 years
Share-based Compensation Arrangement by Share-based Payment Award, Options, Cumulative Forfeitures of Plan (in shares)						3,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number, Ending Balance (in shares)						148,000		148,000	226,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross (in shares)						0	0
Share Price (in dollars per share) | $ / shares						$ 27.87		$ 27.87
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Intrinsic Value | $						$ 1.3
Share-based Payment Arrangement, Option [Member]
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount, Total | $						$ 0.1		$ 0.1
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition (Year)						1 year 6 months
Restricted Stock Units (RSUs) [Member]
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount, Total | $						$ 27.2		27.2
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition (Year)						2 years 4 months 24 days
Employee Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Maximum Employee Subscription Rate				10.00%	10.00%
Share-based Compensation Arrangement by Share-based Payment Award, Purchase Price of Common Stock, Percent				85.00%
Share-based Compensation Arrangement by Share-based Payment Award, Offering Period		24 months			24 months
Share-based Compensation Arrangement by Share-based Payment Award, Number of Purchase Period | item					4
Stock Issued During Period, Shares, Employee Stock Purchase Plans (in shares)						95,243	99,674
Employee Stock Purchase Plan Weighted Average Purchase Price of Shares Purchased (in dollars per share) | $ / shares						$ 15.77	$ 9.24
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount, Total | $						$ 1.9		$ 1.9
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition (Year)						1 year 4 months 24 days
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period (Year)		10 years
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period (Year)					6 months
Twenty Eleven Stock Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized (in shares)			11,550,000
Share Based Compensation Arrangement By Share Based Payment Award Shares Reserved Decrease Rate (in shares)			1.33
Common Stock, Capital Shares Reserved for Future Issuance (in shares)	12,800,000					12,100,000		12,100,000
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant (in shares)						3,200,000		3,200,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Cumulative Forfeitures of Plan (in shares)								500,000
Number of additional common stock capital shares reserved for future issuance	1,250,000
Twenty Eleven Stock Incentive Plan [Member] | Share-based Payment Arrangement, Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period (Year)			10 years
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period (Year)			4 years
Shares Previously Issued Under the 2001 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized (in shares)										3,500,000
Outside of the 2011, 2001 or IDS Plans [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number, Ending Balance (in shares)						0		0

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Note 7 - EMPLOYEE BENEFIT PLANS - Stock Options, Valuation Assumptions (Details) - Employee Stock Purchase Plan [Member] - $ / shares	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Expected life (in years) (Year)	1 year 3 months	1 year 3 months
Volatility	48.90%	34.25%
Risk-free interest rate	0.86%	1.43%
Expected dividend	0.00%	0.00%
Weighted average fair value of purchase rights granted during the period (in dollars per share)	$ 10.76	$ 4.83

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Note 7 - EMPLOYEE BENEFIT PLANS - Allocation of Recognized Period Costs (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Stock-based compensation expenses	$ 5,553	$ 3,369
Cost of Sales [Member]
Stock-based compensation expenses	728	652
Research and Development Expense [Member]
Stock-based compensation expenses	3,168	1,588
Selling, General and Administrative Expenses [Member]
Stock-based compensation expenses	$ 1,657	$ 1,129

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Note 7 - EMPLOYEE BENEFIT PLANS - Stock Options Activity (Details) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2022 USD ($) $ / shares shares	Mar. 31, 2021 shares
EMPLOYEE BENEFIT PLANS
Outstanding, beginning balance (in shares)	226
Granted (in shares)	0	0
Exercised (in shares)	(75)
Canceled (in shares)	(3)
Outstanding, ending balance (in shares)	148
Vested and expected to vest (in shares)	146
Exercisable (in shares)	121
Outstanding, weighted average exercise price, beginning balance (in dollars per share) | $ / shares	$ 12.78
Exercised, weighted average exercise price (in dollars per share) | $ / shares	9.06
Canceled, weighted average exercise price (in dollars per share) | $ / shares	13.57
Outstanding, weighted average exercise price, ending balance (in dollars per share) | $ / shares	14.64
Vested and expected to vest, weighted average exercise price (in dollars per share) | $ / shares	14.63
Exercisable, weighted average exercise price (in dollars per share) | $ / shares	$ 14.54
Outstanding, weighted average remaining contractual (Year)	4 years 2 months 8 days
Vested and expected to vest, weighted average remaining contractual term (Year)	4 years 1 month 24 days
Exercisable, weighted average remaining contractual term (Year)	3 years 5 months 12 days
Outstanding, aggregate intrinsic value | $	$ 1,954
Vested and expected to vest, aggregate intrinsic value | $	1,936
Exercisable, aggregate intrinsic value | $	$ 1,612

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Note 7 - EMPLOYEE BENEFIT PLANS - Nonvested Restricted Stock Units Activity (Details) - Restricted Stock Units (RSUs) [Member] shares in Thousands	3 Months Ended
	Mar. 31, 2022 $ / shares shares
Nonvested, Balance (in shares) | shares	1,872
Granted (in shares) | shares	275
Vested (in shares) | shares	(344)
Forfeited (in shares) | shares	(30)
Nonvested, Balance (in shares) | shares	1,773
Nonvested, weighted average grant date fair value (in dollars per share) | $ / shares	$ 18.24
Granted, weighted average grant date fair value (in dollars per share) | $ / shares	27.90
Vested, weighted average grant date fair value (in dollars per share) | $ / shares	19.73
Forfeited, weighted average grant date fair value (in dollars per share) | $ / shares	18.43
Nonvested, weighted average grant date fair value (in dollars per share) | $ / shares	$ 19.45

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Note 8 - INCOME TAXES (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
INCOME TAXES
Increase (Decrease) in Income Taxes	$ 200
Income Tax Expense (Benefit), Total	$ 1,187	$ 956
Effective Income Tax Rate Reconciliation, Percent, Total	40.00%		14.00%
Unrecognized Tax Benefits, Ending Balance	$ 15,000		$ 14,700
Unrecognized Tax Benefits that Would Impact Effective Tax Rate	2,000		1,900
Unrecognized tax benefits including income tax penalties and interest accrued in long term liabilities	2,600
Unrecognized tax benefits related to income tax penalties and interest accrued in long-term liabilities	700
Unrecognized Tax Benefits In Deferred Tax Assets	13,100
Deferred Tax Assets, Valuation Allowance, Total	51,600		51,600
Net deferred tax assets	$ 67		$ 75

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Note 9 - NET LOSS PER SHARE - Calculation of Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
NET LOSS PER SHARE
Net loss	$ (4,150)	$ (7,597)
Basic weighted-average shares outstanding (in shares)	37,606	36,974
Diluted weighted-average shares outstanding (in shares)	37,606	36,974
Basic (in dollars per share)	$ (0.11)	$ (0.21)
Diluted (in dollars per share)	$ (0.11)	$ (0.21)

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Note 9 - NET LOSS PER SHARE - Anti-dilutive Securities (Details) - shares shares in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Anti-dilutive securities (in shares)	1,101	1,341
Share-based Payment Arrangement, Option [Member]
Anti-dilutive securities (in shares)	102	224
Restricted Stock Units (RSUs) [Member]
Anti-dilutive securities (in shares)	905	1,107
Employee Stock Purchase Plan [Member]
Anti-dilutive securities (in shares)	94	10

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Note 10 - CUSTOMER AND GEOGRAPHIC INFORMATION - Other (Details)	3 Months Ended
	Mar. 31, 2022
CUSTOMER AND GEOGRAPHIC INFORMATION
Number of Operating Segments	1
Number of Reportable Segments	1

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Note 10 - CUSTOMER AND GEOGRAPHIC INFORMATION - Revenue Percentage by Major Customers (Details) - Customer Concentration Risk [Member]	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Revenue Benchmark [Member] | Customer A [Member]
Concentration risk		13.00%
Revenue Benchmark [Member] | Customer D [Member]
Concentration risk	33.00%
Revenue Benchmark [Member] | Customer E [Member]
Concentration risk		11.00%
Accounts Receivable [Member] | Customer C [Member]
Concentration risk		15.00%
Accounts Receivable [Member] | Customer D [Member]
Concentration risk	43.00%	29.00%

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Note 10 - CUSTOMER AND GEOGRAPHIC INFORMATION - Revenues by Geographic Area (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Revenues	$ 33,498	$ 24,200
Geographic Concentration Risk [Member] | Revenue Benchmark [Member]
Revenues	$ 33,498	$ 24,200
Concentration risk	100.00%	100.00%
Geographic Concentration Risk [Member] | Revenue Benchmark [Member] | UNITED STATES
Revenues	$ 17,491	$ 8,556
Concentration risk	52.00%	35.00%
Geographic Concentration Risk [Member] | Revenue Benchmark [Member] | CHINA
Revenues	$ 4,120	$ 1,739
Concentration risk	12.00%	7.00%
Geographic Concentration Risk [Member] | Revenue Benchmark [Member] | JAPAN
Revenues	$ 2,607	$ 3,578
Concentration risk	8.00%	15.00%
Geographic Concentration Risk [Member] | Revenue Benchmark [Member] | Rest of the World [Member]
Revenues	$ 9,280	$ 10,327
Concentration risk	28.00%	43.00%

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Note 10 - CUSTOMER AND GEOGRAPHIC INFORMATION - Long-lived Assets by Geographic Area (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Long-lived assets, net	$ 41,323	$ 40,703
UNITED STATES
Long-lived assets, net	40,602	39,158
Rest of the World [Member]
Long-lived assets, net	$ 721	$ 1,545

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Note 11 - FAIR VALUE MEASUREMENTS - Fair Value, Assets Measured on a Recurring Basis (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Total	$ 117,460	$ 125,016
Fair Value, Inputs, Level 1 [Member]
Total	117,460	125,016
Money Market Funds [Member]
Money market mutual funds	19,017	12,474
Money Market Funds [Member] | Fair Value, Inputs, Level 1 [Member]
Money market mutual funds	19,017	12,474
US Government Corporations and Agencies Securities [Member]
Short-term investments	98,443	112,542
US Government Corporations and Agencies Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Short-term investments	$ 98,443	$ 112,542

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Note 12 - COMMITMENTS AND CONTINGENCIES (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2022 USD ($)
Future Lease payments	$ 6,956
Term of Product Warranty	90 days
Purchase Obligation, Total	$ 12,800
Threshold payment period	12 months
Accrued amount	$ 0
Operating Lease Agreement
Future Lease payments	$ 700
Term of operating lease	3 years

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Note 13 - SUBSEQUENT EVENTS (Details) - Subsequent Event $ in Millions	Apr. 12, 2022 USD ($) shares
Subsequent Events
Repurchase common stock | shares	715,000
Open market value | $	$ 16.7