Summary of Significant Accounting Policies and Basis of Presentation (Policies)	3 Months Ended
Mar. 31, 2023
Accounting Policies [Abstract]
Basis of Presentation	The unaudited condensed consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (U.S. GAAP). The Company has issued shares of Class A common stock herein referred to as “Class A common stock” or “Class A” and Class B common stock herein referred to as “Class B common stock” or “Class B,” and collectively as “common stock.” The unaudited condensed consolidated financial statements include the accounts of Seer, Inc. and its wholly-owned subsidiaries. All intercompany transactions and balances have been eliminated.
Use of Estimates	Use of Estimates The preparation of unaudited condensed consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, and the disclosure of contingent assets and liabilities at the date of the unaudited condensed consolidated financial statements and the reported amounts of expenses during the reporting period. On an ongoing basis, the Company evaluates its estimates and assumptions, including, but not limited to, those related to the determination of stand-alone selling price for revenue recognition, the fair value of common stock, stock-based compensation, accrued research and development expenses, allowance for credit losses, inventory valuation, useful lives and valuation of property and equipment, income tax uncertainties, and tax valuation allowances. Management bases its estimates on historical experience and on various other assumptions that are believed to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities that are not readily apparent from other sources. Actual results may differ materially from those estimates.
Concentration of Credit Risk and Other Risks and Uncertainties	Concentration of Credit Risk and Other Risks and Uncertainties Financial instruments that potentially subject the Company to significant concentrations of credit risk consist primarily of cash, cash equivalents, and investments. The Company maintains bank deposits in federally insured financial institutions, and these deposits may exceed federally insured limits. The Company is exposed to credit risk in the event of default by the financial institutions holding its cash and cash equivalents and issuers of investments to the extent account balances exceed the amount insured by the Federal Deposit Insurance Corporation (FDIC). On March 10, 2023, Silicon Valley Bank (SVB) was closed by the California Department of Financial Protection and Innovation and the FDIC was appointed as receiver. On March 27, 2023, First-Citizens Bank & Trust Company assumed all of SVB's deposits and loans. In light of the foregoing, the Company does not believe that it has exposure to loss as a result of SVB’s receivership. As of March 31, 2023, the Company held $0.8 million in SVB and has not experienced any losses on its deposits of cash, cash equivalents and investments. For the three months ended March 31, 2023 and 2022, the Company recognized revenue from a related party that represented 32% of the Company’s total revenue. For the three months ended March 31, 2023, 22% of the total revenue was generated outside of the United States, primarily from countries in Asia and Europe. For the three months ended March 31, 2022, 25% of the total revenue was generated outside of the United States, primarily from countries in Asia and Europe. As of March 31, 2023 and December 31, 2022, there was one related party customer which represented 23% and 25%, respectively, of the total accounts receivable balance. As of December 31, 2022, there were two additional customers which represented 10% and 12% of the total accounts receivable balance.
Cash and Cash Equivalents and Restricted Cash	Cash and Cash Equivalents and Restricted Cash The Company considers all highly liquid investments with an original maturity of three months or less at the date of purchase to be cash equivalents. As of March 31, 2023 and December 31, 2022, all amounts recorded as cash and cash equivalents consist of cash and money market funds and are stated at fair value. Restricted cash as of March 31, 2023 and December 31, 2022 represents cash held by a financial institution as security for a letter of credit issued to the lessor for one of the Company’s operating leases and is classified as noncurrent.
Accounts Receivable, Net	Accounts Receivable, Net Accounts receivable consist of amounts due from customers for the sales of products and services, net of any allowance for credit losses. The Company’s expected loss allowance methodology for receivables is developed using its historical collection experience, current and future economic market conditions and a review of the current aging status and financial condition of its customers. Balances are written off when they are ultimately determined to be uncollectible.
Revenue Recognition	Revenue Recognition The Company generates revenue from sales of products and services. The Company’s product, the Proteograph Product Suite, consists of an instrument with embedded software essential to the instrument's functionality, and consumables as well as platform evaluation agreements. The Company began recognizing revenue from shipments of its Proteograph Product Suite during the second quarter of 2021. The service revenue primarily consists of revenue received from the generation and analysis of proteomic data on behalf of the customer and revenue is recognized upon delivery of the reports. The Company recognizes revenue when control of the products and services is transferred to its customers in an amount that reflects the consideration it expects to be entitled to receive from its customers in exchange for those products and services. This process involves identifying the contract with a customer, determining the performance obligations in the contract, determining the transaction price, allocating the transaction price to the distinct performance obligations in the contract, and recognizing revenue when the performance obligations have been satisfied. A performance obligation is considered distinct from other obligations in a contract when it provides a benefit to the customer either on its own or together with other resources that are readily available to the customer and is distinct within the context of the contract. The Company considers a performance obligation satisfied once it has transferred control of a good or service to the customer, meaning the customer has the ability to direct the use and obtain substantially all the economic benefits from the good or service. Revenue is recorded net of discounts and sales taxes collected on behalf of governmental authorities. Customers are invoiced generally upon shipment, or upon order for services, and payment is typically due within 30 or 60 days. Cash received from customers in advance of product shipment or providing services is recorded as a contract liability. The Company’s contracts with its customers generally do not include rights of return. At times, the Company may enter into arrangements with payment terms which exceed one year from the transfer of control of the product or service. In such cases, the Company assesses whether the arrangement contains a significant financing component. If a significant financing component exists, the transaction price is adjusted for the financing portion of the arrangement, which is recorded as interest income over the payment term using the effective interest method. The Company does not assess whether a significant financing component exists when, at contract inception, the period between the transfer of control to a customer and final payment is one year or less. The Company elected the practical expedient to account for shipping and handling activities that occur after the customer has obtained control as a fulfillment activity and not a separate performance obligation. The Company expenses incremental costs of obtaining a contract as and when incurred if the expected amortization period is one year or less or the amount is immaterial. The Company excludes from the transaction price all taxes assessed by a governmental authority on revenue-producing transactions that are collected by the Company from a customer. The Company regularly enters into contracts that include various combinations of products and services, which are generally distinct and accounted for as separate performance obligations. The transaction price is allocated to each performance obligation in proportion to its standalone selling price. The Company determines the standalone selling price using average selling prices with consideration of current market conditions. If the product or service has no history of sales or if the sales volume is not sufficient, the Company relies upon prices set by management, adjusted for applicable discounts. Grant and Other Revenue Grant revenue represents funding under cost reimbursement programs from federal foundation sources for qualified research and development activities performed by the Company and are not based on estimates that are subject to change. Grants received are assessed to determine if the agreement should be accounted for as an exchange transaction or a contribution. An agreement is accounted for as a contribution if the resource provider does not receive commensurate value in return for the assets transferred. Such amounts are recorded as revenue as grant- funded activities are performed up to the amount of expenses incurred. Any advance funding payments are recorded as deferred revenue until the activities are performed. The Company recognizes revenue for research and development services contracts when control is transferred, which is upon completion of the services and when results of the services have been transferred to the customer. Upfront payments and fees received are recorded as deferred revenue until the Company performs its obligations under its arrangements. Amounts payable to the Company are recorded as other receivables when its right to consideration is unconditional. A portion of the Company’s revenue relates to lease arrangements. Standalone lease arrangements are outside the scope of ASC 606 and are therefore accounted for in accordance with ASC 842. Each of these contracts is evaluated as a lease arrangement, either as an operating lease or a sales-type lease using the lease classification guidance. The total consideration in a lease arrangement is allocated between lease and non-lease components on their relative stand-alone selling prices. The stand-alone selling price is based on the price the Company would sell that promised good or service separately to a customer. If a stand-alone price is not available for a component, it is estimated using the best information available.
Income Taxes	Income Taxes Beginning in 2022, the Tax Cuts and Jobs Act of 2017 eliminates the option to deduct research and development expenditures in the period incurred and requires amortization over five years or fifteen years pursuant to Internal Revenue Code Section 174. The Company has reflected this change in legislation in its annual tax provision included in the Annual Report on Form 10-K filed with the SEC on March 6, 2023 and it does not result in any material impact on its financial position, results of operations or cash flows.
Fair Value Measurements	The carrying amount of the Company’s accounts receivable, other receivables, prepaid expenses and other current assets, accounts payable, and accrued expenses approximate fair value due to their short maturities.

Summary of Significant Accounting Policies and Basis of Presentation (Policies)

3 Months Ended

Mar. 31, 2023

The unaudited condensed consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (U.S. GAAP). The Company has issued shares of Class A common stock herein referred to as “Class A common stock” or “Class A” and Class B common stock herein referred to as “Class B common stock” or “Class B,” and collectively as “common stock.” The unaudited condensed consolidated financial statements include the accounts of Seer, Inc. and its wholly-owned subsidiaries. All intercompany transactions and balances have been eliminated.

Use of Estimates

The preparation of unaudited condensed consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, and the disclosure of contingent assets and liabilities at the date of the unaudited condensed consolidated financial statements and the reported amounts of expenses during the reporting period. On an ongoing basis, the Company evaluates its estimates and assumptions, including, but not limited to, those related to the determination of stand-alone selling price for revenue recognition, the fair value of common stock, stock-based compensation, accrued research and development expenses, allowance for credit losses, inventory valuation, useful lives and valuation of property and equipment, income tax uncertainties, and tax valuation allowances.

Management bases its estimates on historical experience and on various other assumptions that are believed to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities that are not readily apparent from other sources. Actual results may differ materially from those estimates.

Concentration of Credit Risk and Other Risks and Uncertainties

Financial instruments that potentially subject the Company to significant concentrations of credit risk consist primarily of cash, cash equivalents, and investments. The Company maintains bank deposits in federally insured

financial institutions, and these deposits may exceed federally insured limits. The Company is exposed to credit risk in the event of default by the financial institutions holding its cash and cash equivalents and issuers of investments to the extent account balances exceed the amount insured by the Federal Deposit Insurance Corporation (FDIC). On March 10, 2023, Silicon Valley Bank (SVB) was closed by the California Department of Financial Protection and Innovation and the FDIC was appointed as receiver. On March 27, 2023, First-Citizens Bank & Trust Company assumed all of SVB's deposits and loans. In light of the foregoing, the Company does not believe that it has exposure to loss as a result of SVB’s receivership. As of March 31, 2023, the Company held $0.8 million in SVB and has not experienced any losses on its deposits of cash, cash equivalents and investments.

For the three months ended March 31, 2023 and 2022, the Company recognized revenue from a related party that represented 32% of the Company’s total revenue.

For the three months ended March 31, 2023, 22% of the total revenue was generated outside of the United States, primarily from countries in Asia and Europe. For the three months ended March 31, 2022, 25% of the total revenue was generated outside of the United States, primarily from countries in Asia and Europe.

As of March 31, 2023 and December 31, 2022, there was one related party customer which represented 23% and 25%, respectively, of the total accounts receivable balance. As of December 31, 2022, there were two additional customers which represented 10% and 12% of the total accounts receivable balance.

Cash and Cash Equivalents and Restricted Cash

The Company considers all highly liquid investments with an original maturity of three months or less at the date of purchase to be cash equivalents. As of March 31, 2023 and December 31, 2022, all amounts recorded as cash and cash equivalents consist of cash and money market funds and are stated at fair value.

Restricted cash as of March 31, 2023 and December 31, 2022 represents cash held by a financial institution as security for a letter of credit issued to the lessor for one of the Company’s operating leases and is classified as noncurrent.

Accounts Receivable, Net

Accounts receivable consist of amounts due from customers for the sales of products and services, net of any allowance for credit losses. The Company’s expected loss allowance methodology for receivables is developed using its historical collection experience, current and future economic market conditions and a review of the current

aging status and financial condition of its customers. Balances are written off when they are ultimately determined to be uncollectible.

Revenue Recognition

The Company generates revenue from sales of products and services. The Company’s product, the Proteograph Product Suite, consists of an instrument with embedded software essential to the instrument's functionality, and consumables as well as platform evaluation agreements. The Company began recognizing revenue from shipments of its Proteograph Product Suite during the second quarter of 2021. The service revenue primarily consists of revenue received from the generation and analysis of proteomic data on behalf of the customer and revenue is recognized upon delivery of the reports.

The Company recognizes revenue when control of the products and services is transferred to its customers in an amount that reflects the consideration it expects to be entitled to receive from its customers in exchange for those products and services. This process involves identifying the contract with a customer, determining the performance obligations in the contract, determining the transaction price, allocating the transaction price to the distinct performance obligations in the contract, and recognizing revenue when the performance obligations have been satisfied. A performance obligation is considered distinct from other obligations in a contract when it provides a benefit to the customer either on its own or together with other resources that are readily available to the customer and is distinct within the context of the contract. The Company considers a performance obligation satisfied once it has transferred control of a good or service to the customer, meaning the customer has the ability to direct the use and obtain substantially all the economic benefits from the good or service.

Revenue is recorded net of discounts and sales taxes collected on behalf of governmental authorities. Customers are invoiced generally upon shipment, or upon order for services, and payment is typically due within 30 or 60 days. Cash received from customers in advance of product shipment or providing services is recorded as a contract liability. The Company’s contracts with its customers generally do not include rights of return.

At times, the Company may enter into arrangements with payment terms which exceed one year from the transfer of control of the product or service. In such cases, the Company assesses whether the arrangement contains a significant financing component. If a significant financing component exists, the transaction price is adjusted for the financing portion of the arrangement, which is recorded as interest income over the payment term using the effective interest method. The Company does not assess whether a significant financing component exists when, at contract inception, the period between the transfer of control to a customer and final payment is one year or less.

The Company elected the practical expedient to account for shipping and handling activities that occur after the customer has obtained control as a fulfillment activity and not a separate performance obligation. The Company expenses incremental costs of obtaining a contract as and when incurred if the expected amortization period is one year or less or the amount is immaterial. The Company excludes from the transaction price all taxes assessed by a governmental authority on revenue-producing transactions that are collected by the Company from a customer.

The Company regularly enters into contracts that include various combinations of products and services, which are generally distinct and accounted for as separate performance obligations. The transaction price is allocated to each performance obligation in proportion to its standalone selling price. The Company determines the standalone selling price using average selling prices with consideration of current market conditions. If the product or service has no history of sales or if the sales volume is not sufficient, the Company relies upon prices set by management, adjusted for applicable discounts.

Grant and Other Revenue

Grant revenue represents funding under cost reimbursement programs from federal foundation sources for qualified research and development activities performed by the Company and are not based on estimates that are subject to change. Grants received are assessed to determine if the agreement should be accounted for as an exchange transaction or a contribution. An agreement is accounted for as a contribution if the resource provider does not receive commensurate value in return for the assets transferred. Such amounts are recorded as revenue as grant-

funded activities are performed up to the amount of expenses incurred. Any advance funding payments are recorded as deferred revenue until the activities are performed.

The Company recognizes revenue for research and development services contracts when control is transferred, which is upon completion of the services and when results of the services have been transferred to the customer. Upfront payments and fees received are recorded as deferred revenue until the Company performs its obligations under its arrangements. Amounts payable to the Company are recorded as other receivables when its right to consideration is unconditional.

A portion of the Company’s revenue relates to lease arrangements. Standalone lease arrangements are outside the scope of ASC 606 and are therefore accounted for in accordance with ASC 842. Each of these contracts is evaluated as a lease arrangement, either as an operating lease or a sales-type lease using the lease classification guidance.

The total consideration in a lease arrangement is allocated between lease and non-lease components on their relative stand-alone selling prices. The stand-alone selling price is based on the price the Company would sell that promised good or service separately to a customer. If a stand-alone price is not available for a component, it is estimated using the best information available.

Income Taxes

Beginning in 2022, the Tax Cuts and Jobs Act of 2017 eliminates the option to deduct research and development expenditures in the period incurred and requires amortization over five years or fifteen years pursuant to Internal Revenue Code Section 174. The Company has reflected this change in legislation in its annual tax provision included in the Annual Report on Form 10-K filed with the SEC on March 6, 2023 and it does not result in any material impact on its financial position, results of operations or cash flows.

Fair Value Measurements

The carrying amount of the Company’s accounts receivable, other receivables, prepaid expenses and other current assets, accounts payable, and accrued expenses approximate fair value due to their short maturities.