Revenue Recognition: The Company recognizes sales and the related cost of sales when the performance obligations are satisfied. The performance obligations are typically satisfied upon shipment of physical goods or as the services are performed over time. In addition to the satisfaction of the performance obligations, the following conditions are required for revenue recognition: an arrangement exists, there is a fixed price, and collectability is reasonably assured. Discounts, returns and allowances related to sales, including an estimated reserve for the returns and allowances, are recorded as reduction of revenue.

Whenever the Company determines that goods or services promised in a contract should be accounted for as a combined performance obligation over time, the Company determines the period over which the performance obligations will be performed and revenue will be recognized. If the Company determines that the performance obligation is satisfied over time, any upfront payment received is initially recorded as deferred revenue on its consolidated balance sheets.

Revenue is then recognized utilizing the output method based on an estimated rate to allocate the transaction price for this performance obligation as products are supplied over the duration of the contract. Certain judgments affect the application of the Company’s revenue recognition policy. For example, when utilizing the output method, the Company estimates total delivery volume based on the Company’s current operating plan, forecast inputs for expected purchases received from the customer, minimum purchase commitments by the customer and historical experience with similar customer contracts. Accordingly, the Company may recognize a different amount of deferred revenue over the next 12-month period if the Company’s plan changes in the future or if the customer informs the Company of changes to their expected purchases. As of December 31, 2023 and 2022, the Company held deferred revenue balances of $3.3 million and $4.0 million, respectively.

The Company may periodically enter into bill-and-hold arrangements upon request by certain customers according to the terms in the contract. Under the terms, the customer makes a fixed commitment to purchase the Company’s goods, however the customer delays the physical transfer of the goods until a later date. In such instances, revenue is recognized when a customer obtains control of the promised goods and the Company has satisfied all of its performance obligations. The Company considers indicators of the transfer of control, which include, but are not limited to, the following: (i) the Company has a present right to payment for the asset, (ii) the customer has legal title to the asset, (iii) the Company has transferred physical possession of the asset, (iv) the customer has the significant risks and rewards of ownership of the asset and (v) the customer has accepted the asset.

In addition, all of the following criteria in a bill-and-hold arrangement must be met to further indicate a customer has obtained control of the goods: (i) the reason for the bill-and-hold arrangement must be substantive, (ii) the requested goods must be identified separately as belonging to the customer, (iii) the requested goods must be ready for physical transfer to the customer, and (iv) the Company cannot have the ability to use the goods or direct the goods to another customer. The Company recognized no revenue under bill-and-hold arrangements during the year ended December 31, 2023. The Company recognized $1.7 million revenue under bill-and-hold arrangements during the year ended December 31, 2022.

Cash, Cash Equivalents and Restricted Cash: All highly liquid interest-bearing investments with short-terms are classified as cash equivalents. The Company’s investments primarily include investments in money market funds managed by banks and low-risk, fixed-income investments with maturities of three months or less when purchased. The carrying value of these cash equivalents approximate their fair value. As of December 31, 2023 and 2022, the Company had cash equivalents of $17.7 million and $10.5 million, respectively, concentrated in money market funds.

The Company classifies cash as restricted when its withdrawal or usage is constrained for a period exceeding three months. As of December 31, 2023 and 2022, $152,000 of cash was classified as restricted, serving as collateral for letters of credit related to the Company’s office space in Los Angeles, California. The lease for the Los Angeles, California office currently expires in March 2027.

Trade Receivables, net: Trade receivables are stated at their net realizable value, net of a sales allowance, an allowance for doubtful trade receivables and expected credit losses. Credit is extended to customers based on an evaluation of their financial condition and other factors. The Company establishes a sales allowance at the time of revenue recognition based on its history of adjustments and credits provided to customers. In determining the necessary allowance for doubtful trade receivables, the Company considers the current aging and financial condition of its customers, the amount of trade receivables in dispute, and current payment patterns. Trade receivables are written off against the allowance when management determines a balance is uncollectible and the Company no longer actively pursues collection of the receivable. Expected credit losses are estimated based upon historical information, current conditions and reasonable and supportable forecasts.

Credit Risk: Financial instruments that potentially expose the Company to concentration of credit risk consist primarily of cash and cash equivalents and trade receivables. Cash and cash equivalents, consist of bank deposits and short-term investments, including low-risk, fixed-income investments and highly liquid investment-grade debt instruments with an original maturity of three months or less. The Company maintains several bank accounts for its operations primarily at three financial institutions in the U.S. and one financial institution in Hong Kong. The Company’s U.S. bank accounts are insured by the Federal Deposit Insurance Corporation (FDIC) up to $250,000 at each institution. Management believes the Company is not exposed to significant credit risk due to the financial position of the depository institutions in which these deposits are held. Notably, the Company engages in a sweep service with the U.S. institution holding the largest portion of the Company's funds. This service conducts nightly transfers, ensuring that the Company's cash balances exceeding the FDIC limit are judiciously distributed to other reputable banking partners. These transfers are strategically executed in amounts below the FDIC threshold, thereby optimizing the Company's cash balance protection. The Company’s trade receivables are derived from sales to its customers. The Company assesses credit risk of its customers through quantitative and qualitative analysis. From this analysis, the Company establishes credit limits and manages the risk exposure. The Company, however, may from time-to-time incur credit losses due to bankruptcy or other failures from its customers to pay.

Inventories: Inventories are comprised of work-in-process and finished goods. Inventories are stated at the lower of cost, determined by the first-in, first-out method, or net realizable value. The inventory on the balance sheet is recorded net of valuation allowances. Labor and overhead has been added to inventory that was manufactured or characterized by the Company. The Company’s normal operating cycle for reference standards is currently longer than one year. The Company regularly reviews inventories on hand and reduces the carrying value for slow-moving and obsolete inventory, inventory not meeting quality standards and inventory subject to expiration. The reduction of the carrying value for slow-moving and obsolete inventory is based on current estimates of future product demand, market conditions and related management judgment. Any significant unanticipated changes in future product demand or market conditions that vary from current expectations could have an impact on the value of inventories.

Leasehold Improvements and Equipment, net: Leasehold improvements and equipment are comprised of leasehold improvements, laboratory equipment, furniture and fixtures, computer equipment, construction in progress and implementations costs for cloud computing arrangements. Leasehold improvements and equipment are carried at cost and depreciated on the straight-line method over the lesser of the estimated useful life of each asset or lease term. Implementation costs related to a cloud computing arrangement are deferred or expensed as incurred, in accordance with the Accounting Standards Update (ASU) 2018-15. Depreciation on equipment under finance lease is included with depreciation on owned assets. Maintenance and repairs are charged to operating expenses as incurred. Improvements and betterments, which extend the lives of the assets, are capitalized.

Intangible assets: Intangible assets include licensing rights and are accounted for based on the fair value of consideration given or the fair value of the net assets acquired, whichever is more reliable. Intangible assets with finite useful lives are amortized using the straight-line method over a period of 10 years, or, for licensed patent rights, the remaining term of the patents underlying licensing rights (considered to be the remaining useful life of the license), whichever is shorter. The useful lives of subsequent milestone payments that are capitalized are the remaining useful life of the initial licensing payment that was capitalized.

The Company’s long-lived assets are reviewed for impairment on a periodic basis or when changes in circumstances indicate the possibility that the carrying amount may not be recoverable. Long-lived assets are grouped at the lowest level for which identifiable cash flows are largely independent of the cash flows of other assets. If the forecast of undiscounted future cash flows is less than the carrying amount of the assets, an impairment charge would be recognized to reduce the carrying value of the assets to fair value. If a possible impairment is identified, the asset group’s fair value is measured relying primarily on a discounted cash flow methodology. During the year ended December 31, 2023, the Company identified intangible assets which were impaired. For further discussion, see Note 8, Intangible Assets, Net. No assets were impaired during the year ended December 31, 2022.

Income Taxes: Deferred taxes are provided on a liability method whereby deferred tax assets are recognized for deductible temporary differences and operating loss and tax credit carryforwards and deferred liabilities are recognized for taxable temporary differences. Temporary differences are the differences between the reported amounts of assets and liabilities and their tax bases. Deferred tax assets are reduced by a valuation allowance when, in the opinion of management, it is more-likely-than-not that some portion or all of the deferred tax assets will not be realized. Deferred tax assets and liabilities are adjusted for the effects of changes in tax laws and rates on the date of enactment.

The Company has not recorded a reserve for any tax positions for which the ultimate deductibility is highly certain but for which there is uncertainty about the timing of such deductibility. The Company files tax returns in all appropriate jurisdictions, which include a U.S. federal tax return and various state tax returns. Open tax years for these jurisdictions are 2020 to 2023, which statutes expire in 2024 to 2027, respectively. When and if applicable, potential interest and penalty costs are accrued as incurred, with expenses recognized in general and administrative expenses in the statements of operations. As of December 31, 2023, the Company has no liability for unrecognized tax benefits.

Share-based Compensation: The Company grants equity awards to recipients through its 2017 Equity Incentive Plan, as amended (the “2017 Plan”), which was approved by stockholders and the Board of Directors. Under the 2017 Plan, the Board of Directors may grant restricted stock or stock options to employees and non-employees. The accounting treatment for share-based payments to employees and non-employees is substantially equivalent. The Company accounts for all share-based compensation costs under the fair value method.

The fair value of the Company’s stock options is estimated at the date of grant using the Black-Scholes option valuation model. For the expected term, the Company uses SEC Staff Accounting Bulletin No. 107 simplified method for “plain vanilla” options with following characteristics: (i) the share options are granted at the market price on the grant date; (ii) exercisability is conditional on performing service through the vesting date on most options; (iii) if an employee terminates service prior to vesting, the employee would forfeit the share options; (iv) if an employee terminates service after vesting, the employee would have 30 to 90 days to exercise the share options; and (v) the share options are nontransferable and non-hedgeable. The volatility assumption is based on the historical volatility of the Company’s common stock with an equivalent remaining expected term. The dividend yield assumption is based on the Company’s history and expectation of future dividend payouts on the common stock. The risk-free interest rate is based on the implied yield available on U.S. treasury zero-coupon issues with an equivalent remaining expected term.

Market conditions that affect vesting of stock options are considered in the grant-date fair value. The issues surrounding the valuation for such awards can be complex and consideration needs to be given for how the market condition should be incorporated into the valuation of the award. The Company considers using other valuation techniques, such as Monte Carlo simulations based on a lattice approach, to value awards with market conditions.

For option grants and restricted stock unit awards without performance conditions, the Company recognizes compensation expense over the requisite vesting period ratably, recognizing expense for each tranche of each grant starting on the grant date. For stock options that have both service and performance conditions, the Company recognizes compensation expense using the graded attribution method. Compensation expense for stock options with performance conditions is recognized only for those awards expected to vest. The Company recognizes forfeitures when they occur.

Fair Value Measurement: The Company follows the provisions of the accounting standard which defines fair value, establishes a framework for measuring fair value and enhances fair value measurement disclosure. Fair value measurements are based on a three-tier hierarchy that prioritizes the use of observable inputs and minimizes the use on unobservable inputs. These tiers include: Level 1, defined as observable inputs such as quoted market prices in active markets; Level 2, defined as inputs other than quoted prices included within Level 1 that are observable for the asset or liability, either directly or indirectly; and Level 3, defined as unobservable inputs for which little or no market data exists, therefore requiring an entity to develop its own assumptions. The fair value hierarchy gives the highest priority to Level 1 inputs and lowest priority to Level 3 inputs. As of December 31, 2023 and 2022, the Company did not have any Level 2 or Level 3 assets or liabilities.

Financial instruments: The estimated fair value of financial instruments has been determined based on the Company’s assessment of available market information and appropriate valuation methodologies. The fair value of the Company’s financial instruments that are included in current assets and current liabilities approximates their carrying value due to their short-term nature. The carrying amounts reported in the balance sheet for capital lease obligations are present values of the obligations, excluding the interest portion.

In June 2016, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) 2016-13, Financial Instruments - Credit Losses (Topic ASC 326): Measurement of Credit Losses on Financial Instruments. The standard’s main goal is to improve financial reporting by requiring earlier recognition of credit losses on financing receivables and other financial assets in scope. The new guidance represents significant changes to accounting for credit losses: (i) full lifetime expected credit losses will be recognized upon initial recognition of an asset in scope; (ii) the current incurred loss impairment model that recognizes losses when a probable threshold is met will be replaced with the expected credit loss impairment method without recognition threshold; and (iii) the expected credit losses estimate will be based upon historical information, current conditions, and reasonable and supportable forecasts. ASU 2016-13 introduces two distinctive credit loss impairment models: (i) current expected credit loss impairment model (Subtopic 326-20) applicable to financial assets measured at amortized cost; and (ii) available-for-sale debt securities impairment model (Subtopic 326-30). The Company adopted this standard on January 1, 2023 using the modified retrospective method resulting in an adjustment to the opening balance of retained earnings of $29,000.

In October 2023, the FASB issued ASU 2023-06, “Disclosure Improvements: Codification Amendments in Response to the SEC’s Disclosure Update and Simplification Initiative,” to amend certain disclosure and presentation requirements for a variety of topics within the ASC. These amendments align the requirements in the ASC to the removal of certain disclosure requirements set out in Regulation S-X and Regulation S-K, announced by the SEC. The effective date for each amended topic in the ASC is either the date on which the SEC’s removal of the related disclosure requirement from Regulation S-X or Regulation S-K becomes effective, or on June 30, 2027, if the SEC has not removed the requirements by that date. Early adoption is prohibited. The Company is currently evaluating the impact that the adoption of ASU 2023-06 may have on its consolidated financial statements and disclosures.

In November 2023, the FASB issued ASU 2023 - 07, "Segment Reporting – Improvements to Reportable Segments Disclosures" (ASU 2023-07), which requires disclosure of significant segment expenses that are regularly provided to the chief operating decision maker (CODM) and included within each reported measure of segment profit or loss, an amount and description of its composition for other segment items to reconcile to segment profit or loss, and the title and position of the entity's CODM. The amendments in ASU 2023-07 also expand the interim segment disclosure requirements. ASU 2023-07 will be effective for fiscal years beginning after December 15, 2023, and interim periods within fiscal years beginning after December 15, 2024. Early adoption is permitted and the amendments in this update are required to be applied on a retrospective basis. The Company is currently evaluating the impact that the adoption of ASU 2023-07 may have on its consolidated financial statements and disclosures.

In December 2023, the FASB issued ASU 2023-09, "Income Taxes (Topic 740): Improvements to Income Tax Disclosures". ASU 2023-09 is intended to enhance the transparency and decision usefulness of income tax disclosures. The amendments in ASU 2023-09 address investor requests for enhanced income tax information primarily through changes to the rate reconciliation and income taxes paid information. A public entity should apply the amendments in ASU 2023-09 prospectively to all annual periods beginning after December 15, 2024. Early adoption and retrospective application are permitted. The Company is currently evaluating the impact of this standard on its consolidated financial statements and related disclosures.