Summary of Significant Accounting Policies (Policies)	9 Months Ended
Sep. 30, 2021
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with generally accepted accounting principles in the United States of America, or GAAP, and the applicable rules and regulations of the Securities and Exchange Commission, or the SEC, for interim reporting. Certain information and note disclosures included in our annual financial statements prepared in accordance with GAAP have been condensed or omitted pursuant to such rules and regulations. The condensed consolidated balance sheet as of December 31, 2020 has been derived from our audited consolidated financial statements, which are included in the prospectus dated June 8, 2021, as filed with the SEC pursuant to Rule 424(b) under the Securities Act of 1933, or the Prospectus. The accompanying condensed consolidated financial statements should be read in conjunction with our consolidated financial statements and notes thereto included in the Prospectus. The accompanying unaudited condensed consolidated financial statements include the accounts of the Company and its wholly owned subsidiaries. All intercompany balances and transactions have been eliminated in consolidation. In the opinion of management, the accompanying condensed consolidated financial statements reflect all adjustments of a normal recurring nature considered necessary for a fair presentation of the Company's consolidated financial position, results of operations, comprehensive loss, and cash flows for the interim periods presented. The interim results for the three and nine months ended September 30, 2021 are not necessarily indicative of the results that may be expected for the year ending December 31, 2021, or for any other future annual or interim period.
Use of Estimates	Use of Estimates The preparation of the financial statements requires management to make estimates and assumptions relating to reported amounts of assets and liabilities, disclosure of contingent assets and liabilities, and reported amounts of revenue and expenses. Significant estimates and assumptions relate to the estimation of variable consideration in contracts with Customers, collectability of accounts receivable, reserve for contract contingencies and processing errors, the useful lives of property and equipment, the incremental borrowing rate used to determine operating lease liabilities, the fair value of equity awards and warrants, and share-based compensation. Actual results could differ materially from these estimates.
Segment Information	Segment Information The Company operates as a single operating segment. The Company's chief operating decision maker is its Chief Executive Officer, who reviews financial information presented on a consolidated basis for purposes of making operating decisions, assessing financial performance, allocating resources and evaluating the Company's financial performance.
Restricted Cash	Restricted Cash Restricted cash consists of deposits with financial institutions that issue payment cards (credit, debit, or prepaid) either on their own behalf or on behalf of businesses that issue customized card products to their end users, or Issuing Banks, to provide the Issuing Bank collateral in the event that Customers’ funds are not deposited at the Issuing Banks in time to settle Customers’ transactions with the networks that provide the infrastructure for settlement and card payment information flows, or Card Networks. Restricted cash also includes cash used to secure a letter of credit for the Company’s lease of its office headquarters in Oakland, California.
Deferred Offering Costs	Deferred Offering Costs Deferred offering costs consist primarily of accounting, legal, and other fees related to the IPO. Upon the completion of the IPO in June 2021, the deferred offering costs were reclassified to stockholders’ equity and recorded net against the proceeds from the IPO.
New Accounting Standards Adopted and Not Yet Adopted	New Accounting Standards Adopted In August 2018, the Financial Accounting Standards Board, or the FASB, issued Accounting Standards Update, or ASU, No. 2018-15, Intangibles—Goodwill and Other— Internal-Use Software (Subtopic 350-40), which aligns the requirements for capitalizing implementation costs incurred in a hosting arrangement that is a service contract with the requirements for capitalizing implementation costs incurred to develop or obtain internal-use software (and hosting arrangements that include an internal use software license). The accounting for the service element of a hosting arrangement that is a service contract is not affected by the amendments in this ASU. The Company adopted the new standard as of January 1, 2021. The adoption of ASU 2018-15 did not have a material impact on the Company's condensed consolidated financial statements. New Accounting Standards Not Yet Adopted As an emerging growth company, the Jumpstart Our Business Startups Act, or the JOBS Act, allows the Company to delay adoption of new or revised accounting pronouncements applicable to public companies until such pronouncements are made applicable to private companies. The Company has elected to use this extended transition period under the JOBS Act. The adoption date discussed below reflects this election. In June 2016, the FASB issued ASU No. 2016-13, Financial instruments – Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments. ASU 2016-13 replaces the incurred loss model with the current expected credit loss, or CECL, model to estimate credit losses for financial assets measured at amortized cost and certain off-balance sheet credit exposures. It also eliminates the concept of other-than-temporary impairment and requires credit losses related to available-for-sale debt securities to be recorded through an allowance for credit losses rather than as a reduction in the amortized cost basis of the securities. The CECL model requires a company to estimate credit losses expected over the life of the financial assets based on historical experience, current conditions and reasonable and supportable forecasts. The guidance will be effective for the Company beginning January 1, 2023, and interim periods therein. The amendment requires a modified retrospective approach by recording a cumulative-effect adjustment to retained earnings as of the beginning of the period of adoption. Early adoption is permitted. The Company is still evaluating the impact this ASU will have on its condensed consolidated financial statements.

Summary of Significant Accounting Policies (Policies)

9 Months Ended

Sep. 30, 2021

The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with generally accepted accounting principles in the United States of America, or GAAP, and the applicable rules and regulations of the Securities and Exchange Commission, or the SEC, for interim reporting. Certain information and note disclosures included in our annual financial statements prepared in accordance with GAAP have been condensed or omitted pursuant to such rules and regulations. The condensed consolidated balance sheet as of December 31, 2020 has been derived from our audited consolidated financial statements, which are included in the prospectus dated June 8, 2021, as filed with the SEC pursuant to Rule 424(b) under the Securities Act of 1933, or the Prospectus. The accompanying condensed consolidated financial statements should be read in conjunction with our consolidated financial statements and notes thereto included in the Prospectus.

The accompanying unaudited condensed consolidated financial statements include the accounts of the Company and its wholly owned subsidiaries. All intercompany balances and transactions have been eliminated in consolidation. In the opinion of management, the accompanying condensed consolidated financial statements reflect all adjustments of a normal recurring nature considered necessary for a fair presentation of the Company's consolidated financial position, results of operations, comprehensive loss, and cash flows for the interim periods presented. The interim results for the three and nine months ended September 30, 2021 are not necessarily indicative of the results that may be expected for the year ending December 31, 2021, or for any other future annual or interim period.

Use of Estimates

The preparation of the financial statements requires management to make estimates and assumptions relating to reported amounts of assets and liabilities, disclosure of contingent assets and liabilities, and reported amounts of revenue and expenses. Significant estimates and assumptions relate to the estimation of variable consideration in contracts with Customers, collectability of accounts receivable, reserve for contract contingencies and processing errors, the useful lives of property and equipment, the incremental borrowing rate used to determine operating lease liabilities, the fair value of equity awards and warrants, and share-based compensation. Actual results could differ materially from these estimates.

Segment Information

The Company operates as a single operating segment. The Company's chief operating decision maker is its Chief Executive Officer, who reviews financial information presented on a consolidated basis for purposes of making operating decisions, assessing financial performance, allocating resources and evaluating the Company's financial performance.

Restricted Cash

Restricted cash consists of deposits with financial institutions that issue payment cards (credit, debit, or prepaid) either on their own behalf or on behalf of businesses that issue customized card products to their end users, or Issuing Banks, to provide the Issuing Bank collateral in the event that Customers’ funds are not deposited at the Issuing Banks in time to settle Customers’ transactions with the networks that provide the infrastructure for settlement and card payment information flows, or Card Networks. Restricted cash also includes cash used to secure a letter of credit for the Company’s lease of its office headquarters in Oakland, California.

Deferred Offering Costs

Deferred offering costs consist primarily of accounting, legal, and other fees related to the IPO. Upon the completion of the IPO in June 2021, the deferred offering costs were reclassified to stockholders’ equity and recorded net against the proceeds from the IPO.

New Accounting Standards Adopted and Not Yet Adopted

New Accounting Standards Adopted

In August 2018, the Financial Accounting Standards Board, or the FASB, issued Accounting Standards Update, or ASU, No. 2018-15, Intangibles—Goodwill and Other— Internal-Use Software (Subtopic 350-40), which aligns the requirements for capitalizing implementation costs incurred in a hosting arrangement that is a service contract with the requirements for capitalizing implementation costs incurred to develop or obtain internal-use software (and hosting arrangements that include an internal use software license). The accounting for the service element of a hosting arrangement that is a service contract is not affected by the amendments in this ASU. The Company adopted the new standard as of January 1, 2021. The adoption of ASU 2018-15 did not have a material impact on the Company's condensed consolidated financial statements.

New Accounting Standards Not Yet Adopted

As an emerging growth company, the Jumpstart Our Business Startups Act, or the JOBS Act, allows the Company to delay adoption of new or revised accounting pronouncements applicable to public companies until such pronouncements are made applicable to private companies. The Company has elected to use this extended transition period under the JOBS Act. The adoption date discussed below reflects this election.

In June 2016, the FASB issued ASU No. 2016-13, Financial instruments – Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments. ASU 2016-13 replaces the incurred loss model with the current expected credit loss, or CECL, model to estimate credit losses for financial assets measured at amortized cost and certain off-balance sheet credit exposures. It also eliminates the concept of other-than-temporary impairment and requires credit losses related to available-for-sale debt securities to be recorded through an allowance for credit losses rather than as a reduction in the amortized cost basis of the securities. The CECL model requires a company to estimate credit losses expected over the life of the financial assets based on historical experience, current conditions and reasonable and supportable forecasts. The guidance will be effective for the Company beginning January 1, 2023, and interim periods therein. The amendment requires a modified retrospective approach by recording a cumulative-effect adjustment to retained earnings as of the beginning of the period of adoption. Early adoption is permitted. The Company is still evaluating the impact this ASU will have on its condensed consolidated financial statements.