You should read the following discussion and analysis of our financial condition and results of operations together with our condensed financial statements and related notes included in this Quarterly Report on Form 10-Q and our audited consolidated financial statements and related notes thereto contained in our Annual Report on Form 10-K for the year endedDecember 31, 2021 . Some of the information contained in this discussion and analysis or set forth elsewhere in this Quarterly Report on Form 10-Q, including information with respect to our plans and strategy for our business, includes forward-looking statements that involve risks and uncertainties. As a result of many important factors, including those set forth under "Special Note Regarding Forward-Looking Statements," in the "Risk Factors" section of this Quarterly Report on Form 10-Q and in the "Risk Factors" section of our Annual Report on Form 10-K for the year endedDecember 31, 2021 , our actual results could differ materially from the results described in, or implied, by those forward-looking statements.
Insight
We are a medical device company focused on developing and commercializing products intended to transform the way calcified cardiovascular disease is treated. We aim to establish a new standard of care for medical device treatment of atherosclerotic cardiovascular disease through our differentiated and proprietary local delivery of sonic pressure waves for the treatment of calcified plaque, which we refer to as intravascular lithotripsy ("IVL"). Our IVL system (our "IVL System"), which leverages our IVL technology (our "IVL Technology"), is a minimally invasive, easy-to-use, and safe way to significantly improve patient outcomes. We are currently selling the following products in a number of countries around the world where we have applicable regulatory approvals:
Products for the treatment of peripheral arterial disease (“PAD”):
•Our Shockwave M5 IVL catheter (the "M5 catheter") and M5+ IVL catheter ("M5+ catheter") are five-emitter catheters for use in our IVL System in "medium" vessels for the treatment of above-the-knee PAD. The M5 catheter was CE-Marked inApril 2018 and cleared by theU.S. Food and Drug Administration ("FDA") inJuly 2018 . The M5+ catheter, for which we are currently initiating a limited market release inthe United States and select international locations, was CE-Marked inNovember 2020 and cleared by the FDA inApril 2021 . •Our Shockwave S4 IVL catheter ("S4 catheter") is a four-emitter catheter for use in our IVL System in small vessels for the treatment of below-the-knee PAD. The second version of our S4 catheter was cleared by the FDA inAugust 2019 and accepted by ourEU notified body inMay 2020 for use in our IVL System.
Product for the treatment of coronary artery disease (“CAD”):
•Our Shockwave C2 IVL catheter ("C2 catheter") is a two-emitter catheter for use in our IVL System for the treatment of CAD. The C2 catheter was CE-Marked inJune 2018 . InAugust 2019 , we received the Breakthrough Device Designation from the FDA for our C2 catheters using our IVL System for the treatment of CAD. InAugust 2020 , we submitted an application to the FDA forU.S. pre-market approval of our C2 catheters, which was approved by the FDA inFebruary 2021 . InMarch 2021 , we submitted DISRUPT CAD III and DISRUPT CAD IV data to support our Shonin submission inJapan for our C2 Catheters and received approval inMarch 2022 . Our differentiated range of M5 and M5+ catheters, S4 catheters and C2 catheters enables delivery of IVL therapy of diseased vasculature throughout the body for calcium modification. Our IVL catheters resemble in form a standard balloon angioplasty catheter, the device most commonly used by interventionalists. This familiarity makes our IVL System easy to learn, adopt and use on a day-to-day basis. Since inception, we have focused on generating clinical data to demonstrate the safety and effectiveness of our IVL Technology. These initial studies have consistently shown low rates of complications regardless of which vessel was being studied. In addition to gaining regulatory approvals or clearances, the data from our clinical studies strengthen our ability to drive adoption of IVL Technology across multiple therapies in existing and new market segments. Our past studies have also guided optimal IVL procedure technique and informed the design of our IVL System and future products in development. In addition, we also have ongoing clinical programs across several products and indications, which, if successful, will allow us to expand commercialization of our products into new geographies and indications.
The first two indications we target with our IVL system are PAD, the narrowing or blockage of vessels that carry blood from the heart to the extremities, and CAD, the narrowing or blockage of arteries that supply blood.
17 -------------------------------------------------------------------------------- heart. In the future, we see significant opportunity in the potential treatment of aortic stenosis, a condition where the heart's aortic valve becomes increasingly calcified with age, causing it to narrow and obstruct blood flow from the heart. We have adapted the use of lithotripsy to the cardiovascular field with the aim of creating what we believe can become the safest, most effective means of addressing the growing challenge of cardiovascular calcification. Lithotripsy has been used to successfully treat kidney stones (deposits of hardened calcium) for over 30 years. By integrating lithotripsy into a device that resembles a standard balloon catheter, physicians can prepare, deliver, and treat calcified lesions using a familiar form factor, without disruption to their standard procedural workflow. Our differentiated IVL System works by delivering shockwaves through the entire depth of the artery wall, modifying calcium in the medial layer of the artery, not just at the superficial most intimal layer. The shockwaves crack this calcium and enable the stenotic artery to expand at low pressures, thereby minimizing complications inherent to traditional balloon dilations, such as dissections or tears. Preparing the vessel with IVL facilitates optimal outcomes with other therapies, including stents and drug-eluting technologies. Using IVL also avoids complications associated with atherectomy devices such as dissection, perforation, and embolism. When followed by an anti-proliferative therapy such as a drug-coated balloons or drug-eluting stents, the micro-fractures may enable better drug penetration into the arterial wall and improve drug uptake, thereby improving the effectiveness of the combination treatment. We market our products to hospitals whose interventional cardiologists, vascular surgeons, and interventional radiologists treat patients with PAD and CAD. We have dedicated meaningful resources to establish a direct sales capability inthe United States ,Germany ,Austria ,Switzerland ,France , and theUnited Kingdom , and we are working to build out our direct sales team inJapan in anticipation of the launch of our C2 catheters, for which we received Japanese regulatory approval inMarch 2022 . We have complemented our direct sales capability with distributors actively selling our products in over 50 countries inNorth and South America ,Europe , theMiddle East ,Asia ,Africa , andAustralia /New Zealand . We are actively expanding our international field presence through new distributors, as well as additional sales and clinical personnel. In addition, we are continuing to add newU.S. sales territories. For the three months endedMarch 31, 2022 and 2021, we generated product revenue of$93.6 million and$31.9 million , respectively, and income from operations of$15.4 million and a loss of operations of$17.5 million , respectively. For the three months endedMarch 31, 2022 and 2021, 16% and 34%, respectively, of our product revenue was generated from customers located outside ofthe United States . Since inception, we have incurred significant net losses. Although we had positive net income for the quarter endedMarch 31, 2022 , we had a net loss for the year endedDecember 31, 2021 . We may continue to incur losses in the future, which may vary significantly from period to period. We expect to continue to incur significant expenses as we (i) expand our marketing efforts to increase adoption of our products, (ii) expand existing relationships with our customers, (iii) obtain regulatory clearances or approvals for our planned or future products, (iv) conduct clinical trials on our existing and planned or future products, and (v) develop new products or add new features to our existing products. We will need to continue to generate significant revenue in order to sustain profitability as we continue to grow our business. Even if we achieve profitability for any period, we cannot be sure that we will remain profitable for any substantial period of time. To date, our principal sources of liquidity have been the net proceeds we received through the sale of our common stock in our public offerings, private sales of equity securities and payments received from customers using our products. As ofMarch 31, 2022 , we had$201.1 million in cash, cash equivalents and short-term investments and an accumulated deficit of$238.3 million .
Impact of the COVID-19 pandemic
The global COVID-19 pandemic presents significant risks to us and has had, and continues to have, far reaching impacts on our business, operations, and financial results and condition, directly and indirectly, including, without limitation, impacts on: the health of our management and employees; our manufacturing, distribution, marketing and sales operations; our research and development activities, including clinical activities; and customer and patient behaviors. Access to many hospitals and other customer sites may be or may periodically be, depending on the current COVID-19 infection rates in the applicable location, restricted to essential personnel, which negatively impacts our ability to promote the use of our products with physicians. Additionally, many hospitals and other therapeutic centers have in the past suspended, and may suspend or continue to suspend in the future, many elective procedures, resulting in a reduced volume of procedures using our products. Our customer behavior is impacted by the prevalence of COVID-19 and changes in the infection rates in the locations where our customers are located. 18 -------------------------------------------------------------------------------- Quarantines, shelter-in-place and similar government orders have also impacted and may continue to impact, our third-party manufacturers and suppliers, and could in turn adversely impact the availability or cost of materials, which could disrupt our supply chain. In addition, we have recently seen some disruptions in the operations of certain of our third-party suppliers, resulting in increased lead-times, higher component costs and lower allocations for our purchase of some components. In certain cases, this has resulted in us being required to procure materials from alternate suppliers or incur higher logistical expenses. We are continuing to work closely with our manufacturing partners and suppliers to enable us to source key components and maintain appropriate inventory levels to meet customer demand. We, however, have not experienced material disruptions in our supply chain to date. We have taken a variety of steps to address the impact of the COVID-19 pandemic, while attempting to minimize business disruption. Essential staff in manufacturing and limited support functions continued to work from our Santa Clara headquarters following appropriate hygiene and social distancing protocols. To reduce the risk to our other employees and their families from potential exposure to COVID-19, until recently all other staff in our Santa Clara headquarters were required to work from home. Certain of these other employees had begun to return to our headquarters full or part-time during the second quarter of 2021, although we continue to review the impact of the omicron variant of COVID-19 on employee safety. We continue to limit non-essential travel to protect the health and safety of our employees and customers. We are continuing to monitor the impact of the COVID-19 pandemic on our employees and customers and on the markets in which we operate, and will take further actions that we consider prudent to address the COVID-19 pandemic, while ensuring that we can support our customers and continue to develop our products. The ultimate extent of the impact of the COVID-19 pandemic on us remains highly uncertain and will depend on future developments and factors that continue to evolve, including the ability of various regions to effectively manage COVID-19, the extent of the continuing resurgence of COVID-19, the efficacy and extent of distribution of vaccines, and the impact of mutations of COVID-19, and the ability of various economies and supply-chains to recover from the COVID-19 pandemic. Most of these developments and factors are outside of our control and could exist for an extended period of time even after the pandemic might end.
Components of our operating results
Product revenue
Product revenue comes primarily from the sale of our IVL catheters.
We sell our products to hospitals, primarily through direct sales representatives, as well as through distributors in selected international markets. For products sold through direct sales representatives, control is transferred upon delivery to customers. For products sold to distributors internationally and products sold to customers that utilize stocking orders, control is transferred upon shipment or delivery to the customer's named location, based on the contractual shipping terms. Additionally, a portion of our revenue is generated through a consignment model under which inventory is maintained at hospitals. For consignment inventory, control is transferred at the time the catheters are consumed in a procedure.
Product revenue cost
Cost of product revenue consists primarily of costs of components for use in our products, the materials and labor that are used to produce our products, the manufacturing overhead that directly supports production and the depreciation relating to the equipment used in our IVL System to the extent that we loan generators to our hospital customers without charge to facilitate the use of our IVL catheters in their procedures. We depreciate equipment over a three-year period. We expect cost of product revenue to increase in absolute terms as our revenue grows. Our gross margin has been and will continue to be affected by a variety of factors, primarily production volumes, the cost of direct materials, product mix, geographic mix, discounting practices, manufacturing costs, product yields, headcount and cost-reduction strategies. We expect our gross margin percentage to marginally increase over the long term to the extent we are successful in increasing our sales volume and are therefore able to leverage our fixed costs. We intend to use our design, engineering and manufacturing capabilities to further advance and improve the efficiency of our manufacturing processes, which, if successful, we believe will reduce costs and enable us to increase our gross margin percentage. While we expect gross margin percentage to increase over the long term, it will likely fluctuate from quarter to quarter as we continue to introduce new products and adopt new manufacturing processes and technologies. 19 --------------------------------------------------------------------------------
Research and development costs
Research and development (“R&D”) expenses include personnel, consulting, material and applicable clinical trial costs. R&D expenses include:
•certain personnel expenses, including salaries, benefits, bonuses, travel and stock-based compensation;
•the cost of clinical studies to support new products and product improvements, including expenses of clinical research organizations and site payments;
•materials and supplies used for internal R&D and clinical activities;
•allocated general expenses, including expenses related to facilities and information technology; and
•the cost of external consultants involved in technology development, regulatory affairs, clinical affairs and quality assurance.
R&D costs are expensed as incurred. In the future, we expect R&D expenses to increase in absolute dollars as we continue to develop new products, enhance existing products and technologies, and perform activities related to obtaining additional regulatory approvals.
Sales and marketing expenses
Sales and marketing expenses consist of personnel-related expenses, including salaries, benefits, sales commissions, travel, and stock-based compensation. Other sales and marketing expenses consist of marketing and promotional activities, including trade shows and market research. We expect to continue to grow our sales force and increase marketing efforts as we continue commercializing products based on our IVL Technology. As a result, we expect sales and marketing expenses to increase in absolute dollars over the long term. General and administrative expenses General and administrative expenses consist of personnel-related expenses, including salaries, benefits, bonus, travel, and stock-based compensation. Other general and administrative expenses consist of professional services fees, including legal, audit and tax fees, insurance costs, outside consultant fees and employee recruiting and training costs. Moreover, we expect to incur additional expenses associated with operating as a public company, including legal, accounting, insurance, exchange listing andSecurities and Exchange Commission ("SEC") compliance and investor relations. As a result, we expect general and administrative expenses to increase in absolute dollars in future periods.
Share in the net loss of the investment under the equity method
The share of net investment loss under the equity method represents our share of the underlying income or loss incurred in our joint venture with
Interest expense
Includes interest and amortization expense related to our outstanding term loan maturing in
Other income (expenses), net
Other income (expense), net, includes interest earned on our cash equivalents and short-term investments and the net impact of foreign exchange gains and losses.
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Operating results
Comparison of the three months ended
The following table shows our results of operations for the three months endedMarch 31, 2022 and 2021: Three Months Ended March 31, Change Change 2022 2021 $ % (in thousands, except percentages) Revenue: Product revenue$ 93,631 $ 31,900 $ 61,731 194% Cost of revenue: Cost of product revenue 12,890 7,892 4,998 63% Gross profit 80,741 24,008 56,733 236% Operating expenses: Research and development 17,019 10,277 6,742 66% Sales and marketing 35,961 23,992 11,969 50% General and administrative 12,389 7,226 5,163 71% Total operating expenses 65,369 41,495 23,874 58% Income (loss) from operations 15,372 (17,487) 32,859 188% Share in net loss of equity method investment (47) (5,523) (5,476) (99)% Interest expense (297) (312) (15) (5)% Other expense, net (310) (235) 75 32% Net income (loss) before taxes 14,718 (23,557) 38,275 162% Income tax provision 197 44 153 348% Net income (loss)$ 14,521 $ (23,601) $ 38,122 162% Product revenue Product revenue increased by$61.7 million , or 194%, from$31.9 million during the three months endedMarch 31, 2021 to$93.6 million during the three months endedMarch 31, 2022 .
The following table represents our product revenues by product line:
Three Months Ended March 31, Change Change 2022 2021 $ % (in thousands, except percentages) Coronary$ 70,337 $ 15,308 $ 55,029 359% Peripheral 22,852 16,141 6,711 42% Other 442 451 (9) (2)% Product revenue$ 93,631 $ 31,900 $ 61,731 194% Coronary product revenue increased by$55.0 million , or 359%, from$15.3 million for the three months endedMarch 31, 2021 to$70.3 million for the three months endedMarch 31, 2022 . InFebruary 2021 , we receivedU.S. FDA approval for our C2 catheters. The increase in coronary product revenue was primarily due to the commencement of sales of our C2 catheters inthe United States , increased adoption of our products internationally, and continued recovery from the impact of the COVID-19 pandemic in the prior year. 21 -------------------------------------------------------------------------------- Peripheral product revenue increased by$6.7 million , or 42%, from$16.1 million for the three months endedMarch 31, 2021 to$22.9 million for the three months endedMarch 31, 2022 . The change was due to an increase in purchase volume of our M5, M5+ and S4 IVL catheters withinthe United States and internationally driven by increased adoption of our products and recovery from the impact of the COVID-19 pandemic in the prior year. We sold to a greater number of customers inthe United States and to a greater number of distributors internationally for the three months endedMarch 31, 2022 as compared to the three months endedMarch 31, 2021 . Product revenue, classified by the major geographic areas in which our products are shipped, was$78.5 million withinthe United States and$15.1 million for all other countries in the three months endedMarch 31, 2022 compared to$21.0 million withinthe United States and$10.9 million for all other countries in the three months endedMarch 31, 2021 .
Cost of Product Revenue, Gross Margin and Gross Margin Percentage
Cost of product revenue increased by$5.0 million , or 63%, from$7.9 million during the three months endedMarch 31, 2021 to$12.9 million during the three months endedMarch 31, 2022 . Gross margin percentage improved to 86% for the three months endedMarch 31, 2022 , compared to 75% for the three months endedMarch 31, 2021 . This change in gross margin percentage was primarily due to a higher average selling price and lower fixed costs per unit from increased sales volume of our IVL catheters and efficiencies from improvements to operations and production.
Research and development costs
The following table summarizes our R&D expenses incurred during the periods presented: Three Months Ended March 31, Change Change 2022 2021 $ % (in thousands) Compensation and personnel-related costs$ 10,534 $ 6,098 $ 4,436 73% Clinical-related costs 1,906 2,519 (613) (24)% Materials and supplies 1,055 27 1,028 3,807% Facilities and other allocated costs 2,023 1,032 991 96% Outside consultants 1,028 467 561 120% Other research and development costs 473 134 339 253%
Total research and development expenditure
66% R&D expenses increased by$6.7 million , or 66%, from$10.3 million during the three months endedMarch 31, 2021 to$17.0 million during the three months endedMarch 31, 2022 . The change was primarily due to a$4.4 million increase in compensation and personnel-related costs due to an increase in headcount, a$1.0 million increase in materials and supplies, a$1.0 million increase in facilities and other allocated costs due to increased information technology, rent and building expenditures, a$0.6 million increase in outside consultants, and a$0.3 million increase in other research and development costs. This was partially offset by a decrease in clinical-related costs of$0.6 million due to completion of patient enrollment for the majority of clinical trials.
Sales and marketing expenses
Sales and marketing expenses increased by$12.0 million , or 50%, from$24.0 million during the three months endedMarch 31, 2021 to$36.0 million during the three months endedMarch 31, 2022 . The change was primarily due to a$6.8 million increase in compensation and personnel-related costs, resulting from increased headcount and commissions driven by increased sales of our products. There was also a$2.9 million increase in travel related costs, a$0.9 million increase in marketing and promotional costs, a$1.1 million increase in facilities and other allocated costs, a$0.3 million increase in professional services and consulting costs, and a$0.2 million increase in general corporate costs. This was partially offset by a$0.2 million decrease in materials and supplies. 22 --------------------------------------------------------------------------------
General and administrative expenses
General and administrative expenses increased by$5.2 million , or 71%, from$7.2 million during the three months endedMarch 31, 2021 to$12.4 million during the three months endedMarch 31, 2022 . The change was primarily due to a$2.3 million increase in compensation and personnel-related costs, a$0.7 million increase in general corporate costs, a$1.4 million increase in professional services and consulting costs, a$0.4 million increase in facilities and other allocated costs, and a$0.4 million increase in travel related costs.
Share in the net loss of the investment under the equity method
The decrease in share in net loss of equity method investment of$5.5 million for the three months endedMarch 31, 2022 was due to in-process research and development costs expensed in the three months endedMarch 31, 2021 .
Interest expense
Interest expense of$0.3 million for the three months endedMarch 31, 2022 was related to our outstanding term loan which matures inDecember 2023 . The term loan requires monthly repayments of principal starting inJuly 2022 .
Other expenses, net
Other expense, net increased by$0.1 million , or 32%, from$0.2 million during the three months endedMarch 31, 2021 to$0.3 million during the three months endedMarch 31, 2022 . The increase in other expense was primarily due to increased foreign exchange losses, partially offset by an increase in interest income due to the increased interest rate environment.
Cash and capital resources
To date, our principal sources of liquidity have been the net proceeds of$280.0 million that we received through the sales of our common stock in our public offerings,$10.0 million of private sales of our equity securities, payments received from customers using our products and to a lesser extent proceeds from our debt financings. We have a number of ongoing clinical trials and expect to continue to make substantial investments in these trials and in additional clinical trials that are designed to provide clinical evidence of the safety and efficacy of our products. We intend to continue to make significant investments in our sales and marketing organization by increasing the number ofU.S. sales representatives and expanding our international marketing programs to help facilitate further adoption among existing hospital accounts and physicians as well as broaden awareness of our products to new hospitals. We also expect to continue to make investments in R&D, regulatory affairs, and clinical studies to develop future generations of products based on our IVL Technology, support regulatory submissions, and demonstrate the clinical efficacy of our products. Moreover, we expect to continue to incur expenses associated with operating as a public company, including legal, accounting, insurance, exchange listing andSEC compliance, investor relations and other expenses. Because of these and other factors, although we had positive net income for the quarter endedMarch 31, 2022 , we had a net loss for the year endedDecember 31, 2021 and we may incur net losses and have negative cash flows from operations in the future.
From
•the cost, timing and results of our clinical trials and regulatory reviews;
•the cost of our research and development activities for new and modified products;
•the cost and timing of establishing sales, marketing and distribution capabilities;
• the terms and timing of any other collaboration, licensing and other agreements we may establish, including any contract manufacturing agreements;
•the timing, receipt and amount of sales of our current and potential products;
•the degree of success we have had in marketing our products;
•the emergence of competing or complementary technologies;
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•the cost of preparing, filing, prosecuting, maintaining, defending and enforcing any patent claims and other intellectual property rights; and
•the extent to which we acquire or invest in businesses, products or technologies, although we currently have no commitments or agreements regarding any of these types of transactions.
To the extent that current and anticipated future sources of liquidity are insufficient to fund our future business activities and cash and other requirements, we may be required to seek additional equity or debt financing. The sale of additional equity would result in additional dilution to our stockholders. The incurrence of additional debt financing would result in debt service obligations and the instruments governing such debt could provide for operating and financing covenants that would restrict our operations. In the event that additional financing is required from outside sources, there is a possibility we may not be able to raise it on terms acceptable to us or at all. If we are unable to raise additional capital when desired, our business, operating results, and financial condition could be adversely affected.
Manufacturing purchase obligations
We have engaged a contract manufacturer to produce and supply us with certain products. We have fixed commitments of approximately$11.1 million within the next twelve months. Operating Leases Our operating lease commitments mostly consist of our lease obligations for our Santa Clara headquarter office spaces. Our total operating lease commitments as ofMarch 31, 2022 are approximately$55.6 million , of which$4.3 million is expected to be paid within the next twelve months.
There have been no other significant changes during the three months ended
We did not have during the periods presented, and we do not currently have, any commitments or obligations, including contingent obligations, arising from arrangements with unconsolidated entities or persons that have or are reasonably likely to have a material current or future effect on our financial condition, changes in financial condition, revenues or expenses, results of operations, liquidity, cash requirements or capital resources.
Cash flow
The following table summarizes our cash flows for the periods indicated:
Three
Months ended
2022 2021 Net cash provided by (used in): (in thousands) Operating activities $ 1,937$ (17,303) Investing activities (27,414) 27,086 Financing activities 2,520 (3,200) Net increase (decrease) in cash, cash equivalents and restricted cash$ (22,957) $ 6,583 Operating activities During the three months endedMarch 31, 2022 , cash provided by operating activities was$1.9 million , attributable to a net income of$14.5 million , non-cash charges of$11.6 million , partially offset by a net change in our net operating assets and liabilities of$24.2 million . Non-cash charges of$11.6 million primarily consisted of$9.5 million in stock-based compensation,$1.0 million in depreciation and amortization, and$0.8 million in amortization of right-of-use assets. The change in our net operating assets and liabilities of$24.2 million was primarily due to a$10.4 million increase in accounts receivable due to an increase in sales, a$10.1 million increase in inventory driven by an increase in raw materials and finished goods inventory, and a$9.1 million decrease in accrued and other current liabilities resulting from payment of accrued bonuses and other compensation in the current quarter. These changes were partially offset by a$4.9 million increase in accounts payable due to the timing of vendor billings. 24 -------------------------------------------------------------------------------- During the three months endedMarch 31, 2021 , cash used in operating activities was$17.3 million , attributable to a net loss of$23.6 million and a net change in our net operating assets and liabilities of$6.0 million and non-cash charges of$12.3 million . Non-cash charges primarily consisted of$5.5 million in share of net loss of equity method investment,$5.1 million in stock-based compensation,$0.7 million in depreciation and amortization,$0.4 million in amortization of right-of-use assets,$0.4 million in accretion of discount on available-for-sale securities and$0.2 million in amortization of debt issuance costs. The change in our net operating assets and liabilities was primarily due to a$7.9 million increase in accounts receivable due to an increase in sales,$3.3 million increase in inventory, and a$0.1 million increase in other assets, prepaid and other current assets and a$0.3 million decrease in lease liabilities. These changes were partially offset by a$5.6 million increase in accrued and other current liabilities and accounts payable resulting primarily from increases in our operating activities and accrued employee compensation due to an increase in headcount.
Investing activities
During the three months endedMarch 31, 2022 , cash used in investing activities was$27.4 million , attributable to purchases of available-for-sale investments of$42.1 million and purchases of property and equipment of$3.3 million , partially offset by proceeds from maturities of available-for-sale investments of$18.0 million . During the three months endedMarch 31, 2021 , cash provided by investing activities was$27.1 million , attributable to proceeds from maturities of available-for-sale investments of$46.4 million , partially offset by purchase of available-for-sale investments of$15.3 million and purchase of property and equipment of$4.1 million . Financing activities During the three months endedMarch 31, 2022 , cash provided by financing activities was$2.5 million , attributable to proceeds of$2.1 million from the issuance of shares under our employee stock purchase plan and proceeds of$0.4 million from stock option exercises.
In the three months ended
Significant Accounting Policies and Estimates
Management's discussion and analysis of our financial condition and results of operations is based on our condensed consolidated financial statements, which have been prepared in accordance withU.S. generally accepted accounting principles ("GAAP"). The preparation of these consolidated financial statements requires us to make estimates and assumptions for the reported amounts of assets, liabilities, revenue, expenses and related disclosures. Our estimates are based on our historical experience and on various other factors that we believe are reasonable under the circumstances, the results of which form the basis for making judgments about the carrying value of assets and liabilities that are not readily apparent from other sources. Actual results may differ from these estimates under different assumptions or conditions and any such differences may be material. There have been no significant changes in our critical accounting policies and assumptions associated with the greatest potential impact on our consolidated financial statements as disclosed in our Annual Report on Form 10-K for the fiscal year endedDecember 31, 2021 in the section titled "Management's Discussion and Analysis of Financial Condition and Results of Operations."
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