in 2019 , we derived approximately 85 % of our sales from the semiconductor device industry . demand for semiconductor devices can fluctuate significantly based on changes in general economic conditions , including consumer spending , demand for the products that include these devices , and other factors . in the past , these fluctuations have resulted in significant variations in our results of operations . the cyclicality of the semiconductor device industries will continue to impact our results of operations in the future . customer concentration the number of capital equipment manufacturers for the semiconductor device industry is significantly consolidated , resulting in a small number of large manufacturers . our customers are a significant component of this consolidation , resulting in our sales being concentrated in a few customers . in 2019 , our top two customers were lam research and applied material , with lam research and applied materials accounting for approximately 51 % and 33 % of sales , respectively . the sales we generated from these customers in 2019 were spread across 35 different product lines utilized in 13 unique manufacturing process steps . we believe the diversity of products that we provide to these customers , combined with the fact that our customers use our products on numerous types of process equipment , lessens the impact of the inherent concentration in the industry . our customers often require reduced prices or other pricing , quality , or delivery commitments as a condition to their purchasing from us in any given period or increasing their purchase volume , which can , among other things , result in reduced gross margins in order to maintain or expand our market share . although we do not have any long-term contracts that require customers to place orders with us , lam research and applied materials have been our customers for over 10 years . acquisitions we acquired cal‑weld , a california-based leader in the design and fabrication of precision , high purity industrial components , subsystems , and systems , in july 2017 for $ 56.2 million . we also acquired talon , a minnesota-based leader in the design and manufacturing of high precision machined parts used in leading edge semiconductor tools , in december 2017 for $ 137.8 million . on a combined basis , these acquisitions contributed approximately $ 57.5 million to sales in 2017. we acquired ian , a seoul-based leader in providing locally-sourced design and manufacturing of gas delivery systems to customers in south korea , for $ 6.5 million , which contributed $ 7.7 million to sales in 2018. these acquisitions continue to have a significant impact on our financial position and results of operations . we intend to continue to evaluate opportunistic acquisitions to supplement our organic growth , and any such acquisitions could have a material impact on our business and results of operations . components of our results of operations the following discussion sets forth certain components of our statements of operations as well as significant factors that impact those items . sales we generate sales primarily from the design , manufacture , and sale of subsystems and components for semiconductor capital equipment . sales are recognized when control of promised goods or services is transferred to our customers , in an amount that reflects the consideration we expect to be entitled to in exchange for those goods or services . our shipping terms are generally “ shipping point . ” accordingly , control transfers , and sales are recognized , at this point-in-time . 31 cost of sales and gross profit cost of sales consists primarily of purchased materials , direct labor , indirect labor , factory overhead cost , and depreciation expense for our manufacturing facilities and equipment , as well as certain engineering costs that are related to non-recurring engineering services that we provide to , and for which we invoice , our customers in connection with their product development activities . our business has a highly variable cost structure with a low fixed overhead structure as a percentage of cost of sales . in addition , our existing global manufacturing plant capacity is scalable and we are able to adjust to increased customer demand for our products without significant additional capital investment . we operate our business in this manner to avoid having excessive fixed costs during a cyclical downturn while retaining flexibility to expand our production volumes during periods of growth . however , this approach results in a smaller increase in gross margin as a percentage of sales in times of increased demand . since the gross margin on each of our products differs , our overall gross margin as a percentage of our sales changes based on the mix of products we sell in any period . operating expenses our operating expenses primarily include research and development and sales , general , and administrative expenses . personnel costs are the most significant component of operating expenses and consist of salaries , benefits , bonuses , share-based compensation , and , with regard to sales and marketing expense , sales commissions . operating expenses also include overhead costs for facilities , it , and depreciation . in addition , our operating expenses include costs related to amortization of intangible assets and restructuring costs . research and development – research and development expense consists primarily of activities related to product design and other development activities , new component testing and evaluation , and test equipment and fixture development . research and development expense does not include engineering costs that are related to non-recurring engineering services that we provide to , and for which we invoice , our customers as part of sales , which are reflected as cost of sales . story_separator_special_tag ( 5 ) represents the release of a valuation allowance against our foreign tax credit carryforwards we now expect to realize as a result of additional analysis of the tax cuts and jobs act . ( 6 ) during the second quarter of 2017 , we corrected an error relating to translated inventory balances at our malaysia and singapore subsidiaries using an incorrect foreign currency rate . the error arose in prior period financial statements beginning in periods prior to 2014 and through 2016. the correction resulted in a $ 1.8 million increase in cost of sales and a corresponding decrease in gross profit in our consolidated statement of operations and a decrease to inventories in our consolidated balance sheet during the second quarter of 2017 . ( 7 ) as part of our purchase price allocations for our acquisitions of cal‑weld in july 2017 , talon in december 2017 , and ian in april 2018 , we recorded acquired-inventory at fair value , resulting in a fair value step-up of $ 3.6 million , $ 6.2 million , and $ 0.3 million , respectively . these amounts were subsequently released to cost of sales as acquired-inventory was sold . 39 ( 8 ) during the third quarter of 2017 , we received a final arbitration ruling on our working capital claim with the sellers of ajax . the ruling was outside the one year measurement period and therefore could not be considered an adjustment to goodwill , resulting in a charge to selling , general , and administrative expense . non-gaap adjusted net income from continuing operations has limitations as an analytical tool , and you should not consider it in isolation or as a substitute for net income or any of our other operating results reported under gaap . other companies may calculate adjusted net income differently or may use other measures to evaluate their performance , both of which could reduce the usefulness of our adjusted net income as a tool for comparison . because of these limitations , you should consider non-gaap adjusted net income from continuing operations alongside other financial performance measures , including net income from continuing operations and other financial results presented in accordance with gaap . in addition , in evaluating non-gaap adjusted net income , you should be aware that in the future we will incur expenses such as those that are the subject of adjustments in deriving adjusted net income and you should not infer from our presentation of adjusted net income that our future results will not be affected by these expenses or any unusual or non-recurring items . unaudited quarterly financial results the following table set forth statement of operations data for the periods indicated . the information for each of these periods is unaudited and has been prepared on the same basis as our audited consolidated financial statements included herein and includes all adjustments , consisting only of normal recurring adjustments that we consider necessary for a fair presentation of our unaudited operations data for the periods presented . historical results are not necessarily indicative of the results to be expected in the future . replace_table_token_12_th 40 the following table sets forth our unaudited quarterly consolidated statement of operations data as a percentage of sales for the periods indicated . replace_table_token_13_th seasonality we have not historically experienced meaningful seasonality with respect to our business or results of operations . story_separator_special_tag roman ; font-size:10pt ; font-weight : normal ; font-style : normal ; text-transform : none ; font-variant : normal ; `` > for a description of our credit facilities , please review the information provided in note 9 – credit facilities of our consolidated financial statements included in part iv , item 15 of this report . 42 contractual obligations and commitments the following summarizes our contractual obligations and commitments as of december 27 , 2019 : replace_table_token_15_th ( 1 ) represents the contractually required principal payments under our credit facilities in accordance with the required principal payment schedule . ( 2 ) represents the contractually required interest payments under our credit facilities in accordance with the required interest payment schedule . interest costs have been estimated based on interest rates in effect for such indebtedness as of december 27 , 2019. critical accounting policies and estimates our consolidated financial statements have been prepared in accordance with u.s. generally accepted accounting principles . the preparation of these consolidated financial statements requires us to make estimates and assumptions that affect the reported amounts of assets , liabilities , sales , expenses , and related disclosures . we base our estimates on historical experience and on various other assumptions that we believe are reasonable under the circumstances . we evaluate our estimates and assumptions on an ongoing basis . actual results may differ from these estimates . to the extent that there are material differences between these estimates and our actual results , our future financial statements will be affected . the critical accounting policies requiring estimates , assumptions , and judgments that we believe have the most significant impact on our consolidated financial statements are described below . revenue recognition to understand our revenue recognition accounting policy , please review the information provided in note 1 – organization and summary of significant accounting policies . inventory valuation to understand our inventory valuation accounting policy , please review the information provided in note 1 – organization and summary of significant accounting policies . during 2019 , 2018 , and 2017 , we wrote down inventory determined to be excessive or obsolete by $ 1.1 million , $ 1.9 million , and $ 0.9 million , respectively . recent accounting pronouncements from time to time , the financial accounting standards board ( “ fasb ” ) or other standards setting bodies issue new accounting pronouncements . updates to the fasb accounting standards codification are communicated through issuance of an accounting standards update ( “ asu ” ) . unless otherwise

liquidity and capital resources we had cash of $ 60.6 million as of december 27 , 2019 , compared to $ 43.8 million as of december 28 , 2018. our principal uses of liquidity are to fund our working capital needs , purchase new capital equipment , acquisitions , and our share repurchase program . the increase was primarily due to operating cash flows of $ 57.2 million and net proceeds from the issuance of ordinary shares under our share-based compensation plans of $ 5.5 million , partially offset by net payments on long-term debt of $ 23.8 million , capital expenditures of $ 12.3 million , cash paid for intangible assets of $ 8.1 million . we believe that our cash , the amounts available under our revolving credit facility , and our cash flows from operations will be sufficient to meet our anticipated cash needs for at least the next 12 months . cash flow analysis the following table sets forth a summary of operating , investing , and financing activities for the periods presented : replace_table_token_14_th operating activities we generated $ 57.2 million from operating activities during 2019 due to net income of $ 10.7 million , net non-cash charges of $ 24.2 million , and a decrease in our net operating assets and liabilities of $ 22.2 million . non-cash charges of $ 24.2 million primarily consist of depreciation and amortization of $ 21.9 million and share-based compensation of $ 8.5 million , partially offset by deferred taxes of $ 7.1 million . the decrease in our net operating assets and liabilities was primarily due to an increase in accounts payable of $ 68.0 million , partially offset by an increase in accounts receivable of $ 44.6 million , resulting from increased purchasing and sales activity as we ended 2019 compared to ending 2018 .


 Write a concise suspicious activity report of the following text delimited by triple backquotes. Return your response as a formal report which covers the key points highlighting the location,dates,entity names and account holder information in chronological order of the text.
     ```liquidity and capital resources we had cash of $ 60.6 million as of december 27 , 2019 , compared to $ 43.8 million as of december 28 , 2018. our principal uses of liquidity are to fund our working capital needs , purchase new capital equipment , acquisitions , and our share repurchase program . the increase was primarily due to operating cash flows of $ 57.2 million and net proceeds from the issuance of ordinary shares under our share-based compensation plans of $ 5.5 million , partially offset by net payments on long-term debt of $ 23.8 million , capital expenditures of $ 12.3 million , cash paid for intangible assets of $ 8.1 million . we believe that our cash , the amounts available under our revolving credit facility , and our cash flows from operations will be sufficient to meet our anticipated cash needs for at least the next 12 months . cash flow analysis the following table sets forth a summary of operating , investing , and financing activities for the periods presented : replace_table_token_14_th operating activities we generated $ 57.2 million from operating activities during 2019 due to net income of $ 10.7 million , net non-cash charges of $ 24.2 million , and a decrease in our net operating assets and liabilities of $ 22.2 million . non-cash charges of $ 24.2 million primarily consist of depreciation and amortization of $ 21.9 million and share-based compensation of $ 8.5 million , partially offset by deferred taxes of $ 7.1 million . the decrease in our net operating assets and liabilities was primarily due to an increase in accounts payable of $ 68.0 million , partially offset by an increase in accounts receivable of $ 44.6 million , resulting from increased purchasing and sales activity as we ended 2019 compared to ending 2018 .
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 Suspicious Activity Report : in 2019 , we derived approximately 85 % of our sales from the semiconductor device industry . demand for semiconductor devices can fluctuate significantly based on changes in general economic conditions , including consumer spending , demand for the products that include these devices , and other factors . in the past , these fluctuations have resulted in significant variations in our results of operations . the cyclicality of the semiconductor device industries will continue to impact our results of operations in the future . customer concentration the number of capital equipment manufacturers for the semiconductor device industry is significantly consolidated , resulting in a small number of large manufacturers . our customers are a significant component of this consolidation , resulting in our sales being concentrated in a few customers . in 2019 , our top two customers were lam research and applied material , with lam research and applied materials accounting for approximately 51 % and 33 % of sales , respectively . the sales we generated from these customers in 2019 were spread across 35 different product lines utilized in 13 unique manufacturing process steps . we believe the diversity of products that we provide to these customers , combined with the fact that our customers use our products on numerous types of process equipment , lessens the impact of the inherent concentration in the industry . our customers often require reduced prices or other pricing , quality , or delivery commitments as a condition to their purchasing from us in any given period or increasing their purchase volume , which can , among other things , result in reduced gross margins in order to maintain or expand our market share . although we do not have any long-term contracts that require customers to place orders with us , lam research and applied materials have been our customers for over 10 years . acquisitions we acquired cal‑weld , a california-based leader in the design and fabrication of precision , high purity industrial components , subsystems , and systems , in july 2017 for $ 56.2 million . we also acquired talon , a minnesota-based leader in the design and manufacturing of high precision machined parts used in leading edge semiconductor tools , in december 2017 for $ 137.8 million . on a combined basis , these acquisitions contributed approximately $ 57.5 million to sales in 2017. we acquired ian , a seoul-based leader in providing locally-sourced design and manufacturing of gas delivery systems to customers in south korea , for $ 6.5 million , which contributed $ 7.7 million to sales in 2018. these acquisitions continue to have a significant impact on our financial position and results of operations . we intend to continue to evaluate opportunistic acquisitions to supplement our organic growth , and any such acquisitions could have a material impact on our business and results of operations . components of our results of operations the following discussion sets forth certain components of our statements of operations as well as significant factors that impact those items . sales we generate sales primarily from the design , manufacture , and sale of subsystems and components for semiconductor capital equipment . sales are recognized when control of promised goods or services is transferred to our customers , in an amount that reflects the consideration we expect to be entitled to in exchange for those goods or services . our shipping terms are generally “ shipping point . ” accordingly , control transfers , and sales are recognized , at this point-in-time . 31 cost of sales and gross profit cost of sales consists primarily of purchased materials , direct labor , indirect labor , factory overhead cost , and depreciation expense for our manufacturing facilities and equipment , as well as certain engineering costs that are related to non-recurring engineering services that we provide to , and for which we invoice , our customers in connection with their product development activities . our business has a highly variable cost structure with a low fixed overhead structure as a percentage of cost of sales . in addition , our existing global manufacturing plant capacity is scalable and we are able to adjust to increased customer demand for our products without significant additional capital investment . we operate our business in this manner to avoid having excessive fixed costs during a cyclical downturn while retaining flexibility to expand our production volumes during periods of growth . however , this approach results in a smaller increase in gross margin as a percentage of sales in times of increased demand . since the gross margin on each of our products differs , our overall gross margin as a percentage of our sales changes based on the mix of products we sell in any period . operating expenses our operating expenses primarily include research and development and sales , general , and administrative expenses . personnel costs are the most significant component of operating expenses and consist of salaries , benefits , bonuses , share-based compensation , and , with regard to sales and marketing expense , sales commissions . operating expenses also include overhead costs for facilities , it , and depreciation . in addition , our operating expenses include costs related to amortization of intangible assets and restructuring costs . research and development – research and development expense consists primarily of activities related to product design and other development activities , new component testing and evaluation , and test equipment and fixture development . research and development expense does not include engineering costs that are related to non-recurring engineering services that we provide to , and for which we invoice , our customers as part of sales , which are reflected as cost of sales . story_separator_special_tag ( 5 ) represents the release of a valuation allowance against our foreign tax credit carryforwards we now expect to realize as a result of additional analysis of the tax cuts and jobs act . ( 6 ) during the second quarter of 2017 , we corrected an error relating to translated inventory balances at our malaysia and singapore subsidiaries using an incorrect foreign currency rate . the error arose in prior period financial statements beginning in periods prior to 2014 and through 2016. the correction resulted in a $ 1.8 million increase in cost of sales and a corresponding decrease in gross profit in our consolidated statement of operations and a decrease to inventories in our consolidated balance sheet during the second quarter of 2017 . ( 7 ) as part of our purchase price allocations for our acquisitions of cal‑weld in july 2017 , talon in december 2017 , and ian in april 2018 , we recorded acquired-inventory at fair value , resulting in a fair value step-up of $ 3.6 million , $ 6.2 million , and $ 0.3 million , respectively . these amounts were subsequently released to cost of sales as acquired-inventory was sold . 39 ( 8 ) during the third quarter of 2017 , we received a final arbitration ruling on our working capital claim with the sellers of ajax . the ruling was outside the one year measurement period and therefore could not be considered an adjustment to goodwill , resulting in a charge to selling , general , and administrative expense . non-gaap adjusted net income from continuing operations has limitations as an analytical tool , and you should not consider it in isolation or as a substitute for net income or any of our other operating results reported under gaap . other companies may calculate adjusted net income differently or may use other measures to evaluate their performance , both of which could reduce the usefulness of our adjusted net income as a tool for comparison . because of these limitations , you should consider non-gaap adjusted net income from continuing operations alongside other financial performance measures , including net income from continuing operations and other financial results presented in accordance with gaap . in addition , in evaluating non-gaap adjusted net income , you should be aware that in the future we will incur expenses such as those that are the subject of adjustments in deriving adjusted net income and you should not infer from our presentation of adjusted net income that our future results will not be affected by these expenses or any unusual or non-recurring items . unaudited quarterly financial results the following table set forth statement of operations data for the periods indicated . the information for each of these periods is unaudited and has been prepared on the same basis as our audited consolidated financial statements included herein and includes all adjustments , consisting only of normal recurring adjustments that we consider necessary for a fair presentation of our unaudited operations data for the periods presented . historical results are not necessarily indicative of the results to be expected in the future . replace_table_token_12_th 40 the following table sets forth our unaudited quarterly consolidated statement of operations data as a percentage of sales for the periods indicated . replace_table_token_13_th seasonality we have not historically experienced meaningful seasonality with respect to our business or results of operations . story_separator_special_tag roman ; font-size:10pt ; font-weight : normal ; font-style : normal ; text-transform : none ; font-variant : normal ; `` > for a description of our credit facilities , please review the information provided in note 9 – credit facilities of our consolidated financial statements included in part iv , item 15 of this report . 42 contractual obligations and commitments the following summarizes our contractual obligations and commitments as of december 27 , 2019 : replace_table_token_15_th ( 1 ) represents the contractually required principal payments under our credit facilities in accordance with the required principal payment schedule . ( 2 ) represents the contractually required interest payments under our credit facilities in accordance with the required interest payment schedule . interest costs have been estimated based on interest rates in effect for such indebtedness as of december 27 , 2019. critical accounting policies and estimates our consolidated financial statements have been prepared in accordance with u.s. generally accepted accounting principles . the preparation of these consolidated financial statements requires us to make estimates and assumptions that affect the reported amounts of assets , liabilities , sales , expenses , and related disclosures . we base our estimates on historical experience and on various other assumptions that we believe are reasonable under the circumstances . we evaluate our estimates and assumptions on an ongoing basis . actual results may differ from these estimates . to the extent that there are material differences between these estimates and our actual results , our future financial statements will be affected . the critical accounting policies requiring estimates , assumptions , and judgments that we believe have the most significant impact on our consolidated financial statements are described below . revenue recognition to understand our revenue recognition accounting policy , please review the information provided in note 1 – organization and summary of significant accounting policies . inventory valuation to understand our inventory valuation accounting policy , please review the information provided in note 1 – organization and summary of significant accounting policies . during 2019 , 2018 , and 2017 , we wrote down inventory determined to be excessive or obsolete by $ 1.1 million , $ 1.9 million , and $ 0.9 million , respectively . recent accounting pronouncements from time to time , the financial accounting standards board ( “ fasb ” ) or other standards setting bodies issue new accounting pronouncements . updates to the fasb accounting standards codification are communicated through issuance of an accounting standards update ( “ asu ” ) . unless otherwise

