Eargo (EAR) 10-K 16 Mar 21 2020 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2020	Mar. 08, 2021	Jun. 30, 2020
Cover [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2020
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	FY
Entity Registrant Name	Eargo, Inc.
Entity Central Index Key	0001719395
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Filer Category	Non-accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	true
Entity Ex Transition Period	false
Entity Shell Company	false
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Common Stock, Shares Outstanding		38,295,422
Entity Public Float			$ 0
Title of 12(b) Security	Common Stock, par value $0.0001 per share
Trading Symbol	EAR
Security Exchange Name	NASDAQ
Entity File Number	001-39616
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	27-3879805
Entity Address, Address Line One	1600 Technology Drive
Entity Address, Address Line Two	6th Floor
Entity Address, City or Town	San Jose
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	95110
City Area Code	650
Local Phone Number	351-7700
Document Annual Report	true
Document Transition Report	false
ICFR Auditor Attestation Flag	false
Documents Incorporated by Reference	None.

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Current assets:
Cash and cash equivalents	$ 212,185	$ 13,384
Accounts receivable, net	3,793	2,051
Inventories	2,739	2,880
Prepaid expenses and other current assets	3,740	1,598
Total current assets	222,457	19,913
Operating lease right-of-use assets	1,079
Property and equipment, net	8,034	5,400
Other assets	1,062	1,992
Total assets	232,632	27,305
Current liabilities:
Accounts payable	6,020	5,428
Accrued expenses	13,909	9,939
Long-term debt, current portion		4,800
Other current liabilities	2,448	1,717
Deferred revenue, current portion	311	406
Lease liability, current portion	1,030
Total current liabilities	23,718	22,290
Lease liability, noncurrent portion	166
Deferred revenue, noncurrent portion		269
Long-term debt, noncurrent portion	14,837	7,446
Convertible preferred stock warrant liability		396
Other liabilities		127
Total liabilities	38,721	30,528
Commitments and contingencies (Note 5)
Convertible preferred stock, $0.0001 par value; zero and 36,269,166 shares authorized as of December 31, 2020 and 2019, respectively; zero and 11,825,812 shares issued and outstanding as of December 31, 2020 and 2019, respectively		152,880
Stockholders’ equity (deficit):
Preferred stock, $0.0001 par value per share; 5,000,000 and zero shares authorized as of December 31, 2020 and 2019, respectively; zero shares issued and outstanding as of December 31, 2020 and 2019, respectively
Common stock; $0.0001 par value; 110,000,000 and 55,190,000 shares authorized as of December 31, 2020 and 2019, respectively; 38,246,601 and 265,943 shares issued and outstanding as of December 31, 2020 and 2019, respectively	4
Additional paid in capital	392,965	3,100
Accumulated deficit	(199,058)	(159,203)
Total stockholders’ equity (deficit)	193,911	(156,103)
Total liabilities, convertible preferred stock and stockholders’ equity (deficit)	$ 232,632	$ 27,305

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2020	Dec. 31, 2019
Statement Of Financial Position [Abstract]
Convertible preferred stock, par value	$ 0.0001	$ 0.0001
Convertible preferred stock, shares authorized	0	36,269,166
Convertible preferred stock, shares issued	0	11,825,812
Convertible preferred stock, shares outstanding	0	11,825,812
Preferred stock, par value	$ 0.0001	$ 0.0001
Preferred stock, shares authorized	5,000,000	0
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, shares authorized	110,000,000	55,190,000
Common stock, shares issued	38,246,601	265,943
Common stock, shares outstanding	38,246,601	265,943

Consolidated Statements of Oper

Consolidated Statements of Operations and Comprehensive Loss - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Statement [Abstract]
Revenue, net	$ 69,154,000	$ 32,790,000	$ 23,163,000
Cost of revenue	21,873,000	15,790,000	11,423,000
Gross profit	47,281,000	17,000,000	11,740,000
Operating expenses:
Research and development	12,045,000	12,841,000	9,520,000
Sales and marketing	49,525,000	35,725,000	25,540,000
General and administrative	20,582,000	12,470,000	8,251,000
Total operating expenses	82,152,000	61,036,000	43,311,000
Loss from operations	(34,871,000)	(44,036,000)	(31,571,000)
Other income (expense), net:
Interest income	37,000	627,000	164,000
Interest expense	(1,920,000)	(711,000)	(424,000)
Other income (expense), net	(1,474,000)	(366,000)	(1,403,000)
Loss on extinguishment of debt	(1,627,000)		(559,000)
Total other income (expense), net	(4,984,000)	(450,000)	(2,222,000)
Loss before income taxes	(39,855,000)	(44,486,000)	(33,793,000)
Income tax provision	0	0	0
Net loss and comprehensive loss	(39,855,000)	(44,486,000)	(33,793,000)
Net loss attributable to common stockholders, basic and diluted	$ (30,015,000)	$ (44,486,000)	$ (33,793,000)
Net loss per share attributable to common stockholders, basic and diluted	$ (3.80)	$ (173.47)	$ (149.69)
Weighted-average shares used in computing net loss per share attributable to common stockholders, basic and diluted	7,890,375	256,452	225,754

Consolidated Statements of Conv

Consolidated Statements of Convertible Preferred Stock and Stockholders' Equity (Deficit) (Unaudited) - USD ($) $ in Thousands	Total	Convertible Preferred Stock	Series C Convertible Preferred Stock	Series E Convertible Preferred Stock	Series D Convertible Preferred Stock	Common Stock	Additional Paid-in Capital	Accumulated Deficit
Beginning balance at Dec. 31, 2017	$ (79,665)						$ 1,259	$ (80,924)
Temporary equity, Beginning balance, Shares at Dec. 31, 2017		5,547,765
Temporary equity, Beginning balance at Dec. 31, 2017		$ 79,129
Beginning balance, Shares at Dec. 31, 2017						224,074
Issuance of convertible preferred stock, net of issuance costs			$ 21,320		$ 51,087
Issuance of convertible preferred stock, net of issuance costs, Shares			2,381,336		3,832,058
Settlement of Series C convertible preferred stock tranche liability on second tranche closing of Series C convertible preferred stock			$ 479
Stock-based compensation	449						449
Exercise of stock options	10						10
Exercise of stock options, Shares						7,757
Net loss and comprehensive loss	(33,793)							(33,793)
Ending balance at Dec. 31, 2018	(112,999)						1,718	(114,717)
Temporary equity, Ending balance, Shares at Dec. 31, 2018		11,761,159
Temporary equity, Ending balance at Dec. 31, 2018		$ 152,015
Ending balance, Shares at Dec. 31, 2018						231,831
Issuance of convertible preferred stock, net of issuance costs					$ 865
Issuance of convertible preferred stock, net of issuance costs, Shares					64,653
Stock-based compensation	1,339						1,339
Exercise of stock options	43						43
Exercise of stock options, Shares						34,112
Net loss and comprehensive loss	(44,486)							(44,486)
Ending balance at Dec. 31, 2019	$ (156,103)						3,100	(159,203)
Temporary equity, Ending balance, Shares at Dec. 31, 2019	11,825,812	11,825,812	3,725,354		3,896,711
Temporary equity, Ending balance at Dec. 31, 2019	$ 152,880	$ 152,880	$ 33,418		$ 51,952
Ending balance, Shares at Dec. 31, 2019						265,943
Issuance of convertible preferred stock, net of issuance costs				$ 67,267
Issuance of convertible preferred stock, net of issuance costs, Shares				10,513,921
Issuance of convertible preferred stock, upon extinguishment of convertible notes				$ 12,818
Issuance of convertible preferred stock, upon extinguishment of convertible notes, Shares				1,889,548
Gain on extinguishment of Series C and Series C-1 convertible preferred stock	9,840	$ (9,840)					9,840
Conversion of convertible preferred stock to common stock upon initial public offering	223,125					$ 3	223,122
Conversion of convertible preferred stock to common stock upon initial public offering, Shares		(24,229,281)
Conversion of convertible preferred stock to common stock upon initial public offering	(223,125)	$ (223,125)
Conversion of convertible preferred stock into common stock upon initial public offering, Shares						28,196,388
Conversion of convertible preferred stock warrants to common stock warrants upon initial public offering	1,931						1,931
Issuance of common stock upon initial public offering, net of underwriting discounts and commissions and other offering costs	148,502					$ 1	148,501
Issuance of common stock upon initial public offering, net of underwriting discounts and commissions and other offering costs, Shares						9,029,629
Exercise of common stock warrants, Shares						107,790
Stock-based compensation	5,292						5,292
Exercise of stock options	1,179						1,179
Exercise of stock options, Shares						646,851
Net loss and comprehensive loss	(39,855)							(39,855)
Ending balance at Dec. 31, 2020	$ 193,911					$ 4	$ 392,965	$ (199,058)
Temporary equity, Ending balance, Shares at Dec. 31, 2020	0
Ending balance, Shares at Dec. 31, 2020						38,246,601

Consolidated Statements of Co_2

Consolidated Statements of Convertible Preferred Stock and Stockholders' Equity (Deficit) (Unaudited) (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Initial Public Offering
Net of underwriting discounts and commissions and other offering costs	$ 14,031
Series C Convertible Preferred Stock
Convertible preferred stock, issuance costs			$ 159
Series D Convertible Preferred Stock
Convertible preferred stock, issuance costs		$ 0	$ 163
Series E Convertible Preferred Stock
Convertible preferred stock, issuance costs	$ 4,056

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Operating activities:
Net loss	$ (39,855)	$ (44,486)	$ (33,793)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	2,525	1,528	695
Stock-based compensation	5,089	1,339	449
Loss on disposal of property and equipment		24
Non-cash interest expense and amortization of debt discount	1,513	297	129
Non-cash operating lease expense	1,128
Bad debt expense	2,352	313
Loss on extinguishment of debt	1,627		559
Change in fair value of financial instruments	1,471	274	506
Changes in operating assets and liabilities:
Accounts receivable	(4,094)	(1,399)	(314)
Inventories	141	(720)	(1,750)
Prepaid expenses and other current assets	(2,142)	(235)	(512)
Other assets	506	(406)	(343)
Accounts payable	187	163	2,540
Accrued expenses	4,467	3,738	2,799
Other current liabilities	731	27	1,520
Deferred revenue	(364)	514	161
Operating lease liabilities	(1,196)
Other liabilities	(127)	(79)	205
Net cash used in operating activities	(26,041)	(39,108)	(27,149)
Investing activities:
Purchases of property and equipment	(1,624)	(2,167)	(1,718)
Capitalized software development costs	(3,455)	(1,692)	(829)
Net cash used in investing activities	(5,079)	(3,859)	(2,547)
Financing activities:
Proceeds from issuance of common stock upon initial public offering, net of underwriting discounts and commissions	151,156
Payments of other offering costs related to the initial public offering	(2,614)	(758)
Proceeds from convertible preferred stock issuance, net of issuance costs	67,867	865	72,407
Proceeds from issuance of convertible notes, net of issuance costs	10,053
Proceeds from debt financing	15,000	5,000	7,000
Debt repayments	(12,720)		(7,689)
Proceeds from PPP loan	4,574
Repayment of PPP loan	(4,574)
Proceeds from stock options exercised	1,179	43	10
Net cash provided by financing activities	229,921	5,150	71,728
Net increase (decrease) in cash and cash equivalents and restricted cash	198,801	(37,817)	42,032
Cash and cash equivalents and restricted cash at beginning of period	13,384	51,201	9,169
Cash and cash equivalents and restricted cash at end of period	212,185	13,384	51,201
Supplemental disclosure of cash flow information:
Cash paid for interest	398	395	563
Non-cash operating activities:
Lease liability obtained in exchange for right-of-use asset	2,392
Cash paid for taxes	63
Non-cash investing and financing activities:
Common stock issued on conversion of convertible preferred stock upon initial public offering	223,125
Conversion of convertible preferred stock warrants to common stock warrants and related reclassification of convertible preferred stock warrant liability to additional paid in capital	1,931
Property and equipment and capitalized software costs in accounts payable and accrued liabilities	393	515	371
Stock-based compensation included in capitalized software costs	203	0	0
Offering costs in accounts payable and accrued liabilities	40	$ 424
Convertible preferred stock issuance costs included in accounts payable	600
Series E Convertible Preferred Stock
Non-cash investing and financing activities:
Issuance of Series E convertible preferred stock upon extinguishment of convertible notes	12,818
Series E Convertible Preferred Stock | Convertible Preferred Stock
Non-cash investing and financing activities:
Issuance of Series E convertible preferred stock upon extinguishment of convertible notes	$ 12,818
Series C Convertible Preferred Stock
Non-cash investing and financing activities:
Settlement of Series C convertible preferred stock tranche liability on second tranche closing of Series C convertible preferred stock			$ 479

Description of Business

Description of Business	12 Months Ended
	Dec. 31, 2020
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Description of Business	Note 1. Description of business Eargo, Inc. (the “Company”) is a medical device company dedicated to improving the quality of life of people with hearing loss. The Eargo solution was developed to create a hearing aid that consumers actually want to use. The Company’s innovative product and go-to-market approach address the major challenges of traditional hearing aid adoption, including social stigma, accessibility and cost. Initial public offering On October 20, 2020, the Company closed its initial public offering (“IPO”) of its common stock in which the Company issued and sold 7,851,852 shares of its common stock, and concurrently sold an additional 1,177,777 shares upon the full exercise of the underwriters’ option to purchase additional shares. The Company sold these shares at $18.00 per share, raising approximately $148.5 million in proceeds, net of underwriting discounts and commissions of $11.4 million and offering costs of $2.6 million. Immediately prior to the closing of the IPO, all outstanding shares of convertible preferred stock were converted into 28,196,388 shares of common stock. Further, all outstanding convertible preferred stock warrants were converted into warrants to purchase 137,812 shares of common stock. Following the IPO, there were no shares of convertible preferred stock or preferred stock outstanding. Reverse stock split In October 2020, the Company’s board of directors approved an amended and restated certificate of incorporation to effect a reverse split of shares of the Company’s common stock and convertible preferred stock on a 3-for-1 basis (the “Reverse Stock Split”), which was filed and effective on October 8, 2020. The number of authorized shares and the par values of the common stock and convertible preferred stock were not adjusted as a result of the Reverse Stock Split. All references to common stock, options to purchase common stock, convertible preferred stock, warrants to purchase convertible preferred stock, share data, per share data and related information contained in the consolidated financial statements have been retrospectively adjusted to reflect the effect of the Reverse Stock Split for all periods presented. Liquidity The Company has incurred losses and negative cash flows from operations since its inception and management expects to incur additional substantial losses in the foreseeable future. As of December 31, 2020, the Company had cash and cash equivalents of $212.2 million and an accumulated deficit of $199.1 million. The Company believes that its existing cash and cash equivalents as of December 31, 2020 will be sufficient for the Company to continue as a going concern for at least one year from the date these consolidated financial statements are filed with the Securities and Exchange Commission (“SEC”). The Company’s future capital requirements will depend on many factors, including its growth rate, the timing and extent of its spending to support research and development activities and the timing and cost of establishing additional sales and marketing capabilities.

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2020
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Note 2. Summary of significant accounting policies Basis of presentation and principles of consolidation The consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”). The consolidated financial statements include the accounts of Eargo, Inc. and its wholly-owned subsidiary. All intercompany balances and transactions have been eliminated. Use of estimates The preparation of consolidated financial statements in conformity with GAAP requires management to make estimates, assumptions, and judgments that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities as of the date of the consolidated financial statements and the reported amounts of revenues and expenses during the reporting period. Significant estimates and assumptions made in the accompanying consolidated financial statements include, but are not limited to, allowance for sales returns, the fair value of lease liabilities, the fair value of equity securities, the fair value of financial instruments, the allowance for doubtful accounts, the net realizable value of inventory, the useful lives of long-lived assets, accrued product warranty reserve, certain other accruals and recoverability of the Company’s net deferred tax assets and the related valuation allowance Cash, cash equivalents and restricted cash Cash equivalents consist of short-term, highly liquid investments with original maturities of three months or less from the purchase date. Cash equivalents consist primarily of amounts invested in money market accounts and are stated at fair value. As of December 31, 2018, the Company had $0.2 million in an outstanding letter of credit related to its operating lease. The letter of credit was collateralized by a restricted cash deposit account consisting of short-term money market funds. The Company does not have any amounts classified as restricted cash as of December 31, 2020 and 2019. The following table provides a reconciliation of cash, cash equivalents and restricted cash reported within the consolidated balance sheets that sum to the total of the same amounts shown in the consolidated statements of cash flows: Year Ended December 31, 2020 2019 2018 (in thousands) Cash and cash equivalents $ 212,185 $ 13,384 $ 51,051 Restricted cash — — 150 Total cash, cash equivalents, and restricted cash $ 212,185 $ 13,384 $ 51,201 Concentration of credit risk Financial instruments that potentially subject the Company to concentrations of credit risk consist of demand deposit accounts, money market accounts and accounts receivable, including credit card receivables. The Company maintains its cash and cash equivalents, which may, at times, exceed federally insured limits, with financial institutions of high credit standing. As of December 31, 2020, the Company has not experienced any losses on its deposit accounts and money market accounts. As of December 31, 2020, the Company does not believe there is significant financial risk from nonperformance by the issuers of the Company’s deposit accounts and money market accounts. Approximately 45% and 39% of the Company’s gross accounts receivable are related to reimbursement from an insurance company as of December 31, 2020 and 2019, respectively. Fair value measurement Fair value is defined as the exchange price that would be received for an asset or paid to transfer a liability, or an exit price, in the principal or most advantageous market for that asset or liability in an orderly transaction between market participants on the measurement date. The Company measures fair value based on a three-level hierarchy of inputs, of which the first two are considered observable and the last unobservable. Unobservable inputs reflect the Company’s own assumptions about current market conditions. The Company maximizes the use of observable inputs, where available, and minimizes the use of unobservable inputs when measuring fair value. The three-level hierarchy of inputs is as follows: Level 1—Observable inputs such as unadjusted, quoted prices in active markets for identical assets or liabilities at the measurement date; Level 2—Observable inputs other than Level 1 prices, such as quoted prices for similar assets or liabilities, quoted prices in markets that are not active, or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities; and Level 3—Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities. To the extent that the valuation is based on models or inputs that are less observable or unobservable in the market, the determination of fair value requires more judgment. Accordingly, the degree of judgment exercised by the Company in determining fair value is greatest for instruments categorized in Level 3. A financial instrument’s level within the fair value hierarchy is based on the lowest level of any input that is significant to the fair value measurement. The carrying amounts reflected in the consolidated balance sheets for cash and cash equivalents, accounts receivable, accounts payable and accrued liabilities approximate their fair values due to their short-term nature. The fair value of the Company’s outstanding term loan is estimated using the net present value of the payments, discounted at an interest rate that is consistent with a market interest rate, which is a Level 2 input. The fair value of the outstanding term loan approximates the carrying amount as the term loan bears a floating rate that approximates the market interest rate. Refer to Note 3 for discussion of certain other financial instruments. Accounts receivable, net Accounts receivable represents amounts due from third-party institutions for credit card and debit card transactions and trade accounts receivable. Accounts receivable are recorded at invoiced amounts, net of allowances for doubtful accounts. The allowance for doubtful accounts is based on the Company’s assessment of the collectibility of accounts. Management regularly reviews the adequacy of the allowance for doubtful accounts by considering the age of each outstanding invoice, each customer’s expected ability to pay, and the collection history with each customer, when applicable, to determine whether a specific allowance is appropriate. The allowance for doubtful accounts charges are recorded as a component of general and administrative expenses in the consolidated statements of operations and comprehensive loss. Inventories Inventories are stated at the lower of standard cost (which approximates actual cost on a first-in, first-out basis) and net realizable value. Inventory consists of purchased components for producing hearing aid products and accessories and finished goods. Provisions for slow-moving, excess or obsolete inventories are recorded when required to reduce inventory values to their estimated net realizable values based on product life cycle, development plans or quality issues. Property and equipment, net Property and equipment are stated at cost, less accumulated depreciation and amortization. Depreciation and amortization on property and equipment is calculated using the straight-line method over the estimated useful lives of the assets, generally three to five years. Leasehold improvements are amortized using the straight-line method over the shorter of the lease term or the estimated useful life of the asset. When assets are retired or otherwise disposed of, the cost and related accumulated depreciation and amortization are removed from the consolidated balance sheets and any resulting gain or loss is reflected in operations in the period realized. Repairs and maintenance are expensed as incurred. Capitalized software development costs The Company capitalizes software purchased for internal use and qualified costs incurred in connection with the development of internal use software. Purchased software consists of software products and licenses, which are amortized over the lesser of their estimated useful life or the contractual term. Internally developed software costs incurred in the preliminary stages of development are expensed as incurred. Once an application has reached the development stage, internal and external direct costs of the development are capitalized until the software is substantially complete and ready for its intended use. The Company also capitalizes costs related to specific upgrades and enhancements when it is probable that the expenditure will result in additional functionality. Internal use software is amortized on a straight-line basis over its estimated useful life, generally three years. Post-implementation activities including training and maintenance are expensed as incurred. Capitalized costs less accumulated amortization are recorded as a component of property and equipment, net on the consolidated balance sheets. Impairment of long-lived assets The Company evaluates its long-lived assets for impairment whenever events or changes in circumstances indicate that the carrying amount of the assets or group of assets may not be fully recoverable. Recoverability is measured by comparing the carrying amount to the future net undiscounted cash flows which the assets are expected to generate. If such assets are considered to be impaired, the impairment to be recognized is measured by the amount by which the carrying amount of the assets exceeds the projected discounted future net cash flows arising from the asset. The Company has not identified any such impairment losses to date. Leases The Company adopted Accounting Standards Codification (“ASC”) Topic 842, “ Leases ROU assets represent the Company’s right to use an underlying asset for the lease term and lease liabilities represent the Company’s obligation to make lease payments arising from the lease. Operating lease ROU assets and liabilities are recognized based on the present value of lease payments over the lease term at the commencement date of the lease. ROU assets also include any initial direct costs incurred and any lease payments made at or before the lease commencement date, less any lease incentive received. As the Company’s leases do not provide an implicit interest rate, the Company uses its incremental borrowing rate based on the information available at the commencement date in determining the present value of lease payments. The Company’s lease terms may include options to extend or terminate the lease when it is reasonably certain that the Company will exercise that option. Lease expense for lease payments is recognized on a straight-line basis over the lease term. The Company elected to exclude from its consolidated balance sheet recognition of leases having a term of 12 months or less (short-term leases) and elected to not separate lease components and non-lease components for its real estate leases. The Company’s non-lease components are primarily related to property maintenance, which varies based on future outcomes, and is recognized in rent expense when incurred. Product warranty The Company provides a one-year or two-year limited warranty on its hearing aid products and accrues for the estimated future costs of repair or replacement upon shipment of the original product. The warranty expense is accrued as a liability and recorded to cost of revenue and is based upon current and historical information for the cost to repair or replace the product. Convertible preferred stock warrant liability The Company accounts for its convertible preferred stock warrants issued in connection with its various financing transactions based upon the characteristics and provisions of the instrument. Convertible preferred stock warrants classified as liabilities are recorded on the consolidated balance sheets at their fair value on the date of issuance and remeasured to fair value at each reporting period, with the changes in fair value recognized as other income (expense), net in the consolidated statements of operations and comprehensive loss. The Company adjusted the liability for changes in the fair value of these warrants until the earlier of the exercise of the warrants, the expiration of the warrants, or until such time as the warrants were no longer considered liability instruments. Upon the closing of the IPO in October 2020, the convertible preferred stock warrants were converted into warrants to purchase common stock and the warrant liabilities were reclassified to additional paid in capital. Derivative liability The Company’s convertible notes issued in 2020 (the “2020 Notes”) contain certain features that meet the definition of embedded derivatives requiring bifurcation from the 2020 Notes as a separate compound financial instrument. The derivative liability is initially measured at fair value on issuance and is subject to remeasurement at each reporting period with changes in fair value recognized in other income (expense), net in the consolidated statements of operations and comprehensive loss. In July 2020, the derivative liability was settled upon the extinguishment of the 2020 Notes. Refer to Note 3 and Note 6 for further discussion. Revenue recognition The Company’s revenue is generated from the sale of products (hearing aid systems and related accessories) and services (extended warranties). These products and services are primarily sold directly to customers through Eargo website and the Company sales representatives. Under ASC 606, revenue is recognized when promised goods or services are transferred to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services by following a five step process: (i) identify the contract(s) with a customer; (ii) identify the performance obligations in the contract; (iii) determine the transaction price; (iv) allocate the transaction price to the performance obligations in the contract; and (v) recognize revenue when (or as) the entity satisfies a performance obligation. Identify the contract with a customer. The Company generally considers completion of an Eargo sales order (which requires customer acceptance of the Company’s click-through terms and conditions for website sales and authorization of payment through credit card or another form of payment for sales made over the phone) as a customer contract provided that collection is considered probable. For payments that are not made upfront by credit card, the Company assesses customer creditworthiness based on credit checks, payment history, and/or other circumstances. For payments involving insurance payors, the Company validates customer eligibility and reimbursement amounts prior to shipping the product. Identify the performance obligations in the contract . Product performance obligations include hearing aid systems and related accessories and service performance obligations include extended warranty coverage. The Company also offers customers a one-time replacement of certain components of the hearing aid system for a fee (i.e., “loss and damage policy”), which represents an option with material right. However, as the historical redemption rate under the policy has been low, the option is not accounted for as a separate performance obligation. The Company does not assess whether promised goods or services are performance obligations if they are immaterial in the context of the contract with the customer. The Company has elected to treat shipping and handling activities performed after a customer obtains control of products as a fulfillment activity. Determine the transaction price and allocation to performance obligations . The transaction price in the Company’s customer contracts consists of both fixed and variable consideration. Fixed consideration includes amounts to be contractually billed to the customer while variable consideration includes the 45-day right of return that applies to all products. To estimate product returns, the Company analyzes historical return levels, current economic trends, and changes in customer demand. Based on this information, the Company reserves a percentage of product sale revenue and accounts for the estimated impact as a reduction in the transaction price. Allocate the transaction price to the performance obligations in the contract . For contracts that contain multiple performance obligations, the Company allocates the transaction price to the performance obligations on a relative standalone selling price basis. Standalone selling prices are based on multiple factors including, but not limited to historical discounting trends for products and services, gross margin objectives, internal costs, competitor pricing strategies, and industry technology lifecycles. Recognize revenue when or as the Company satisfies a performance obligation . Revenue for products (hearing aid systems and related accessories) is recognized at a point in time, which is generally upon shipment. Revenue for services (extended warranty) is recognized over time on a ratable basis over the warranty period. Contract costs The Company applies the practical expedient to recognize the incremental costs of obtaining a contract as expense when incurred if the amortization period would be one year or less. These incremental costs include processing fees paid to third-party financing vendors, who provide the Company’s customers with the option to finance their purchase. If a customer elects to utilize this service, the Company receives a non-recourse upfront payment for the product sold, less processing fee withheld by the financing vendor. These processing fees are recognized in cost of revenue in the consolidated statements of operations and comprehensive loss as incurred. Cost of revenue Cost of revenue consists of expenses relating to the cost of finished goods, freight, personnel costs, consumables, warranty costs, transaction fees including processing fees paid to third-party financing vendors, allocated facility overhead costs, depreciation and amortization. Research and development Research and development expenses consist of personnel costs, travel expenses, tools, prototype materials and product certification and are charged to expense as incurred. Sales and marketing Sales and marketing expenses consist of personnel costs, travel expenses, consulting fees, public relations costs, direct marketing, advertising and promotional expenses and allocated facility overhead costs. The Company recorded advertising costs, which are expensed as incurred, of $23.6 million, $18.6 million and $12.3 million for the years ended December 31, 2020, 2019 and 2018, respectively. Stock-based compensation The Company accounts for stock-based payment awards at fair value. The fair value of stock options and purchase rights granted under the employee stock purchase plan are measured using the Black-Scholes option-pricing model. For stock-based awards that vest subject to the satisfaction of a service requirement, the fair value measurement date is the date of grant and the expense is recognized on a straight-line basis over the requisite service period. For stock-based awards with performance-based vesting conditions, the expense is recognized over the vesting period using the accelerated attribution method. The Company accounts for forfeitures as they occur. Prior to the Company’s IPO in October 2020, the Company had not recognized any stock-based compensation associated with grants that vest upon satisfaction of both a service condition and a performance condition that is satisfied upon the closing of the IPO as the performance condition was not considered probable. Upon the closing of the IPO, the Company recorded stock-based compensation using the accelerated attribution method for the service period rendered from the date of grant through the closing of the IPO as the performance condition was achieved. Income taxes The Company uses the asset and liability method to account for income taxes. Under this method, deferred tax assets and liabilities are determined based on the differences between the financial statement carrying amounts of existing assets and liabilities and their tax bases. Deferred tax assets and liabilities are measured using enacted tax rates applied to taxable income in the years in which those temporary differences are expected to be recovered or settled. A valuation allowance is established when necessary to reduce deferred tax assets to the amount expected to be realized. Financial statement effects of uncertain tax positions are recognized when it is more-likely-than-not that the position will be sustained upon examination. Interest and penalties related to unrecognized tax benefits are included within the provision for income tax. Segments Operating segments are defined as components of an entity for which separate financial information is available and that is regularly reviewed by the Chief Operating Decision Maker (“CODM”) in deciding how to allocate resources to an individual segment and in assessing performance. The Company’s CODM is its Chief Executive Officer. To date, the Company has viewed its operations and manages its business as one operating and reportable segment, with all operations in the United States. Employee benefit plan The Company sponsors a qualified 401(k) defined contribution plan covering eligible employees. Participants may contribute a portion of their annual compensation limited to a maximum annual amount set by the Internal Revenue Service. There have been no employer contributions under this plan to date. Net loss per share attributable to common stockholders The Company follows the two-class method when computing net loss per share as the Company has issued shares that meet the definition of participating securities. The two-class method determines net loss per share for each class of common and participating securities according to dividends declared or accumulated and participation rights in undistributed earnings. The two-class method requires income available to common stockholders for the period to be allocated between common and participating securities based upon their respective rights to receive dividends as if all income for the period had been distributed. Basic net loss per share attributable to common stockholders is calculated by dividing the net loss attributable to common stockholders by the weighted-average number of shares of common stock outstanding for the period, without consideration for potential dilutive securities. Diluted net loss attributable to common stockholders is computed by adjusting net loss attributable to common stockholders to reallocate undistributed earnings based on the potential impact of dilutive securities. Diluted net loss per share is computed by dividing the net loss by the weighted-average number of common shares and common share equivalents of potentially dilutive securities outstanding for the period. For purposes of the diluted net loss per share calculation, convertible preferred stock, convertible notes, convertible preferred stock warrants and common stock options are considered to be potentially dilutive securities. Emerging growth company status The Company is an emerging growth company, as defined in the Jumpstart Our Business Startups Act of 2012 (the “JOBS Act”). Under the JOBS Act, emerging growth companies can delay adopting new or revised accounting standards issued subsequent to the enactment of the JOBS Act until such time as those standards apply to private companies. The Company has elected to use this extended transition period for complying with new or revised accounting standards that have different effective dates for public and private companies until the earlier of the date that it (i) is no longer an emerging growth company or (ii) affirmatively and irrevocably opts out of the extended transition period provided in the JOBS Act. As a result, these consolidated financial statements may not be comparable to companies that comply with the new or revised accounting pronouncements as of public company effective dates. Recently adopted accounting pronouncements In February 2016, the FASB issued Accounting Standards Update (“ASU”) 2016-02, Leases (Topic 842) which amended existing guidance to require substantially all leases to be recognized by lessees on their balance sheet as a right-of-use (“ROU”) asset and corresponding lease liability, including leases previously accounted for as operating leases. Leases (Topic 840) In August 2018, the FASB issued ASU 2018-13 , Fair Value Measurement (Topic 820): Disclosure Framework—Changes to the Disclosure Requirements for Fair Value Measurement Recent accounting pronouncements not yet adopted In June 2016, the FASB issued ASU 2016-13, Financial Instruments—Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments In December 2019, the FASB issued ASU No. 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2020
Fair Value Disclosures [Abstract]
Fair Value Measurements	Note 3. Fair value measurements The following table summarizes the Company’s financial assets and liabilities that were measured at fair value on a recurring basis by level within the fair value hierarchy: December 31, 2019 Level 1 Level 2 Level 3 Total (in thousands) Liabilities: Convertible preferred stock warrant liability $ — $ — $ 396 $ 396 There were no financial assets and liabilities outstanding that were remeasured at fair value on a recurring basis as of December 31, 2020. Convertible preferred stock warrant liability The Company estimates the fair value of its convertible preferred stock warrant liability using the Black-Scholes option-pricing model, assumptions that are based on the individual characteristics of the warrants on the valuation date, and assumptions related to the fair value of the underlying stock, expected volatility, expected life, dividends, and risk-free interest rate. Due to the nature of these inputs, the warrants are considered a Level 3 liability. Upon the closing of the IPO in October 2020, the convertible preferred stock warrants were converted into warrants to purchase common stock and the warrant liabilities were reclassified to additional paid in capital. The following table provides a summary of the change in the estimated fair value of the Company’s convertible preferred stock warrant liability: Total (in thousands) Balance — December 31, 2018 $ 81 Fair value of convertible preferred stock warrants issued in connection with debt financing 41 Change in fair value of warrant liability 274 Balance — December 31, 2019 396 Fair value of convertible preferred stock warrants issued in connection with debt financing 270 Change in fair value of warrant liability 1,265 Conversion of preferred stock warrants to common stock warrants upon the closing of the IPO (1,931 ) Balance — December 31, 2020 $ — The fair value of the convertible preferred stock warrants, which were converted to common stock warrants upon the closing of the IPO in October 2020, was determined using the following assumptions: December 31, Valuation assumptions: 2020 2019 Expected volatility 67%—71% 43%—67% Expected term 2.17—9.9 years 1.0—8.6 years Risk-free interest rate 0.15%—0.75% 1.59%—1.88% Dividend yield — — Derivative liability The 2020 Notes contain embedded derivatives requiring bifurcation as a single compound derivative instrument. The Company estimated the fair value of the derivative liability on issuance using a “with-and-without” method. The “with-and-without” methodology involves valuing the whole instrument on an as-is basis and then valuing the instrument without the individual embedded derivative. The difference between the entire instrument with the embedded derivative compared to the instrument without the embedded derivative was the fair value of the derivative liability on issuance. The estimated probability and timing of underlying events triggering the redemption features, conversion feature or put option contained within the 2020 Notes are inputs used to determine the estimated fair value of the entire instrument with the embedded derivative. The following table provides a summary of the change in the estimated fair value of the Company’s derivative liability: Total (in thousands) Balance — December 31, 2019 $ — Initial fair value of derivative liability 2,879 Change in fair value of derivative liability 206 Extinguishment of derivative liability (3,085 ) Balance — December 31, 2020 $ — In July 2020, the embedded derivative liability was settled upon the extinguishment of the 2020 Notes. Refer to Note 6 for further discussion.

Balance Sheet Components

Balance Sheet Components	12 Months Ended
	Dec. 31, 2020
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Balance Sheet Components	Note 4. Balance sheet components Inventories Inventories consist primarily of raw materials related to component parts and finished goods. The following is a summary of the Company’s inventories by category: December 31, 2020 2019 (in thousands) Raw materials $ 853 $ 1,115 Finished goods 1,886 1,765 Total inventories $ 2,739 $ 2,880 Property and equipment, net Property and equipment, net, consists of the following: December 31, 2020 2019 (in thousands) Tools and lab equipment $ 4,426 $ 2,885 Capitalized software 6,744 3,148 Furniture and fixtures 906 906 Leasehold improvements 757 757 Computer and equipment 288 423 13,121 8,119 Less accumulated depreciation and amortization (5,087 ) (2,719 ) Total property and equipment, net $ 8,034 $ 5,400 Depreciation and amortization for the years ended December 31, 2020 and 2019 amounted to $2.5 million and $1.5 million, respectively, which includes amortization of capitalized software costs of $0.8 million and $0.3 million, respectively. Accrued expenses Accrued expenses consist of the following: December 31, 2020 2019 (in thousands) Allowance for sales returns $ 4,326 $ 3,759 Accrued compensation 5,861 2,739 Accrued vendor costs 751 2,776 Refunds due to customers 581 215 Accrued warranty reserve 2,390 450 Total accrued expenses $ 13,909 $ 9,939 Allowance for doubtful accounts The allowance for doubtful accounts consists of the following activity: Year ended December 31, 2020 2019 2018 (in thousands) Allowance for doubtful accounts, beginning balance $ 225 $ — $ — Charged to expense 2,352 225 — Accounts written off, net of recoveries (709 ) — — Allowance for doubtful accounts, ending balance $ 1,868 $ 225 $ — Allowance for sales returns The allowance for sales returns consists of the following activity: Year ended December 31, 2020 2019 2018 (in thousands) Allowance for sales returns, beginning balance $ 3,759 $ 2,713 $ 1,198 Charged to revenue 22,676 17,739 17,848 Utilization of allowance for sales returns (22,109 ) (16,693 ) (16,333 ) Allowance for sales returns, ending balance $ 4,326 $ 3,759 $ 2,713 Accrued warranty reserve The accrued warranty reserve consists of the following activity: Year ended December 31, 2020 2019 2018 (in thousands) Accrued warranty reserve, beginning balance $ 450 $ 53 $ 39 Charged to cost of revenue 3,178 1,589 57 Utilization of accrued warranty reserve (1,238 ) (1,192 ) (43 ) Accrued warranty reserve, ending balance $ 2,390 $ 450 $ 53

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2020
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	Note 5. Commitments and contingencies Operating leases The Company has entered into non-cancelable operating leases for its offices. These leases generally contain scheduled rent increases and renewal options, which are not included in the determination of lease term unless the Company is reasonably certain that the renewal option would be exercised. As of December 31, 2020, the Company recorded an aggregate ROU asset of $1.1 million and an aggregate lease liability of $1.2 million in the accompanying consolidated balance sheet. The ROU asset and corresponding lease liability were estimated using a weighted-average incremental borrowing rate of 7.1 %. The weighted-average remaining lease term is 1.1 years. For the year ended December 31, 2020, the Company incurred $1.3 million of operating lease costs. Variable lease payments for operating expenses and costs related to short-term leases were immaterial for the year ended December 31, 2020. As of December 31, 2020, undiscounted future minimum lease payments due under the non-cancelable operating leases are as follows: Operating leases (in thousands) 2021 $ 1,074 2022 167 Total minimum future lease payments 1,241 Present value adjustment for minimum lease commitments (45 ) Total lease liability $ 1,196 Litigation The Company may become involved in legal proceedings in the ordinary course of its business. The Company does not believe that any lawsuits or claims currently pending against it, individually or in the aggregate, are material, or will have a material adverse effect on its financial condition, results of operations or cash flows. The Company is subject to review from federal and state taxing authorities in order to validate the amounts of income, sales and/or use taxes which have been claimed and remitted. The Company has estimated exposure and established reserves for its estimated sales tax audit liability. In the normal course of business, the Company may agree to indemnify third parties with whom it enters into contractual relationships, including customers, lessors, and parties to other transactions with the Company, with respect to certain matters. The Company has agreed, under certain conditions, to hold these third parties harmless against specified losses, such as those arising from a breach of representations or covenants, other third-party claims that the Company’s products, when used for their intended purposes, infringe the intellectual property rights of such other third parties, or other claims made against certain parties. It is not possible to determine the maximum potential amount of liability under these indemnification obligations due to the Company’s limited history of prior indemnification claims and the unique facts and circumstances that are likely to be involved in each particular claim.

Debt Obligations

Debt Obligations	12 Months Ended
	Dec. 31, 2020
Debt Disclosure [Abstract]
Debt Obligations	Note 6. Debt obligations 2018 Loan Agreement In June 2018, the Company entered into a Loan and Security Agreement (the “2018 Loan Agreement”) with Silicon Valley Bank. Under the terms of the 2018 Loan Agreement, Silicon Valley Bank made available to the Company term loans in an aggregate principal amount of $12.5 million and the Company borrowed $5.0 million in October 2018, $1.0 million in November 2018 and $1.0 million in December 2018. The term loans under the 2018 Loan Agreement mature in June 2022, with interest-only monthly payments for a specified period of time. Interest on the term loans accrued at a per annum rate equal to the Wall Street Journal prime rate minus 1.0% with a floor of 0.0%. In connection with the execution of the 2018 Loan Agreement, the Company issued warrants to purchase 30,173 shares of Series C convertible preferred stock. The estimated fair value of the warrants at issuance was recorded as a discount on the loan and is amortized to interest expense over the term of the agreement using the effective interest method. Amendments to the 2018 Loan Agreement In January 2019, the Company executed the First Amendment to the Loan and Security Agreement, which extended the interest-only period for all borrowings under the agreement until January 2020. No other terms were amended. In June 2019, the Company borrowed an additional $5.0 million to increase the total principal balance to $12.0 million. In connection with the June 2019 borrowing, the Company issued Silicon Valley Bank warrants to purchase 14,999 shares of Series C convertible preferred stock. In May 2020, the Company executed the Second Amendment to its Loan and Security Agreement, which deferred the principal payments due between May 2020 and July 2020 such that the deferred amounts will be repaid in equal monthly payments that started in August 2020 through the scheduled maturity of the loan in June 2022. The amendment was accounted for as a modification. In September 2020, the Company executed the Third Amendment to the Loan and Security Agreement (the “Third Amendment”), under which Silicon Valley Bank made available to the Company additional term loans in an aggregate principal amount of $20.0 million through December 31, 2020. The Company borrowed $15.0 million in September 2020 and used $10.2 million of the proceeds to repay the outstanding balance of $9.5 million and final payment fee of $0.7 million, or 6.0% of the original aggregate principal amount, on the existing term loan. The Company’s ability to borrow any additional principal under the Third Amendment expired unused on December 31, 2020. The term loan under the Third Amendment matures in September 2024 with interest-only monthly payments until January 2022, which was extended to July 2022 upon the completion of the Company’s IPO in October 2020. The term loan accrues interest at a per annum rate equal to the Wall Street Journal prime rate plus 1.0% (4.25% as of December 31, 2020) and includes a final payment fee equal to 6.25% of the original aggregate principal amount. In connection with the execution of the Third Amendment, the Company issued Silicon Valley Bank a warrant to purchase 53,487 shares of Series E convertible preferred stock. The amendment was accounted for as a modification. Borrowings under the Third Amendment are collateralized by substantially all the assets of the Company, excluding intellectual property (but including rights to payment and proceeds thereof). The Third Amendment contains customary affirmative and restrictive covenants, including with respect to the Company’s ability to enter into fundamental transactions, incur additional indebtedness, grant liens, pay any dividend or make any distributions to its holders, make investments, merge or consolidate with any other person or engage in transactions with the Company’s affiliates, but do not include any financial covenants. The Company was in compliance with all of the covenants as of December 31, 2020. During the years ended December 31, 2020, 2019 and 2018, the Company recognized interest expense related to the term loans of $1.0 million, $0.7 million and $0.1 million, respectively, which is inclusive of amortization of debt discount. The effective interest rate was 7.12% as of December 31, 2020. The balance of the term loans is as follows: December 31, 2020 2019 (in thousands) Principal value of long-term debt $ 15,000 $ 12,000 Net of debt discount and accretion of final payment (163 ) 246 Long-term debt, current and noncurrent 14,837 12,246 Less: Long-term debt, current portion — (4,800 ) Long-term debt, noncurrent portion $ 14,837 $ 7,446 Future minimum payments of principal and estimated payments of interest on the Company’s outstanding variable rate borrowings as of December 31, 2020 are as follows: Total (in thousands) 2021 $ 646 2022 3,950 2023 7,038 2024 6,028 Total future payments 17,662 Less amounts representing interest (1,724 ) Less final payment (938 ) Total principal amount of term loan payments $ 15,000 Paycheck Protection Program loan On May 3, 2020, the Company executed a promissory note with MidFirst Bank, which provided for an unsecured loan in an aggregate principal amount of $4.6 million (the “PPP Loan”) pursuant to the Paycheck Protection Program under the Coronavirus Aid, Relief and Economic Security Act signed into law on March 27, 2020. The PPP Loan provided for a fixed interest rate of 1.0% per year with a maturity date of May 3, 2022. Monthly principal and interest payments due on the PPP Loan were deferred for a six-month period beginning from the date of disbursement of the PPP Loan. The PPP Loan allowed for prepayment by the Company at any time prior to maturity with no prepayment penalty. The Note contained customary event of default provisions. In August 2020, the Company repaid the PPP Loan in full in the amount of $4.6 million and terminated the related promissory note. During the year ended December 31, 2020, the Company recognized interest expense related to the PPP Loan of less than $0.1 million. 2020 Convertible Promissory Notes The Company issued an aggregate of $8.9 million in convertible promissory notes in March 2020 (the “2020 Notes”) and an additional aggregate of $1.2 million in April 2020 in a subsequent closing. The 2020 Notes accrued interest at a rate of 6.0% per annum and mature in March 2021. Upon maturity, the majority note holders have the option of having outstanding principal and unpaid accrued interest paid in cash or converted into Series D convertible preferred stock. In the event of a qualified sale of preferred stock or other equity securities resulting in aggregate gross proceeds to the Company of at least $15.0 million, all principal and accrued and unpaid interest under the 2020 Notes would automatically convert into the preferred stock issued in such a financing at a price per share equal to 80% of the lowest price per share of the preferred stock sold in the financing (redemption feature). In the event of an IPO, all principal and accrued and unpaid interest under the 2020 Notes would automatically convert into common stock at a price per share equal to 90% of the public offering price (redemption feature). The 2020 Notes also contained an option whereby in the event of a change of control event, at the option of the holders holding a majority in outstanding principal amount of the 2020 Notes, all principal and accrued and unpaid interest under the 2020 Notes would be convertible into the Company’s Series D convertible preferred stock at its original issue price (conversion feature) or, alternatively, such holders may elect to require the Company to pay to all 2020 Note holders an amount equal to the principal amount then outstanding and any accrued but unpaid interest plus an amount equal to 100% of the outstanding principal and accrued and unpaid interest (put option). The above mentioned redemption features, conversion feature and the put option contained in the 2020 Notes were determined to be embedded derivatives requiring bifurcation and separately accounted for as a single compound derivative instrument. Upon the issuances of the 2020 Notes, the Company recorded the fair value of the derivative liability of $2.9 million as a debt discount on the 2020 Notes and as a single compound derivative instrument. The debt discount was being amortized to interest expense using the effective interest method over the term of the 2020 Notes. During the year ended December 31, 2020, the Company recognized interest expense related to the 2020 Notes of $0.9 million, which is inclusive of amortization of debt discount. In July 2020, the 2020 Notes were redeemed whereby the outstanding principal balance of $10.1 million and accrued interest of $0.2 million was converted into 1,889,548 shares of Series E convertible preferred stock at a conversion price of $5.427 per share, a price equal to 80% of the $6.7836 per share paid by the investors in the Series E preferred stock financing. The redemption of the 2020 Notes was accounted for as a debt extinguishment, which resulted in a loss of $1.6 million that was recognized in other income (expense) in the consolidated statement of operations and comprehensive loss. The loss on extinguishment was calculated as the difference between (i) the fair value of the shares of Series E convertible preferred stock issued to settle the 2020 Notes and (ii) the carrying value of the 2020 Notes, net of the unamortized debt discount, plus the fair value of the derivative liability associated with the 2020 Notes at the time of extinguishment.

Convertible Preferred Stock and

Convertible Preferred Stock and Stockholders Equity (Deficit)	12 Months Ended
	Dec. 31, 2020
Temporary Equity Disclosure [Abstract]
Convertible Preferred Stock and Stockholders Equity (Deficit)	Note 7. Convertible preferred stock and stockholders’ equity (deficit) In connection with the IPO, the Company filed an amended and restated certificate of incorporation effective immediately Convertible preferred stock Convertible preferred stock as of December 31, 2019 consisted of the following: December 31, 2019 Shares authorized Shares issued and outstanding Net carrying value Aggregate liquidation preference (in thousands, except share amounts) Series A convertible preferred stock 1,283,000 423,713 $ 16,130 $ 16,271 Series B convertible preferred stock 83,000 27,652 2,229 2,473 Series B-1 convertible preferred stock 2,540,000 838,892 22,871 23,003 Series C convertible preferred stock 11,284,680 3,725,354 33,418 33,603 Series C-1 convertible preferred stock 8,740,486 2,913,490 26,280 21,024 Series D convertible preferred stock 12,338,000 3,896,711 51,952 52,115 Total convertible preferred stock 36,269,166 11,825,812 $ 152,880 $ 148,489 In July and August 2020, the Company issued an aggregate of 10,513,921 shares of Series E convertible preferred stock at a purchase price of $6.7836 per share in exchange for net proceeds of approximately $67.3 million. Contemporaneous with the initial closing of the Series E convertible preferred stock financing, the 2020 Notes (see Note 6) were redeemed whereby all of the outstanding principal and accrued interest amounting to $10.3 million was converted into 1,889,548 shares of Series E convertible preferred stock. In connection with the Series E convertible preferred stock financing, the Company amended and restated its certificate of incorporation to effect anti-dilution adjustments to prior series of convertible preferred stock that were issued, which changed the conversion prices for each share of convertible preferred stock from $27.87, $60.60, $9.0201, $9.0201, $7.2162 and $13.374 for the Series A convertible preferred stock, Series B convertible preferred stock, Series B-1 convertible preferred stock, Series C convertible preferred stock, Series C-1 convertible preferred stock and Series D convertible preferred stock, respectively, to $19.599, $39.6303, $8.0625, $8.0625, $6.9585, $10.7271, respectively. The amended and restated certificate of incorporation filed in connection with the Series E convertible preferred stock financing also amended the liquidation right held by holders of Series C and Series C-1 convertible preferred stock under which such holders were entitled to an aggregate liquidation amount per share from up to two times the original issue price to one times the original issuance price for the related series upon the event of a liquidation, dissolution, or winding up of the Company. This amendment of the liquidation right was determined to be significant using the qualitative approach. As such, the Company accounted for the amendment as an extinguishment of the outstanding Series C and Series C-1 convertible preferred stock and recorded a gain on extinguishment of $9.8 million on the date of the filing of the charter. The gain on the extinguishment of Series C and Series C-1 convertible preferred stock was calculated by taking the difference between the net carrying value of $59.7 million of Series C and Series C-1 convertible preferred stock immediately prior to the amendment of the liquidation right and the fair value of $49.9 million of the new of Series C and Series C-1 convertible preferred stock that for accounting purposes was deemed to be issued in connection with the amended and restated certificate of incorporation filed in connection with the Series E convertible preferred stock financing. The gain on extinguishment was recorded as a deemed contribution in equity and was recorded as a decrease to the net loss attributable to common stockholders for the year ended December 31, 2020 and as an increase to additional paid in capital. In October 2020, immediately prior to the completion of the IPO (see Note 1), all of the then-outstanding shares of convertible preferred stock automatically converted into 28,196,388 shares of common stock at the applicable conversion ratio then in effect. Preferred stock warrants Immediately prior to the closing of the IPO, all of the then-outstanding convertible preferred stock warrants were converted into warrants to purchase 137,812 shares of common stock and the convertible preferred stock warrant liability was reclassified to additional paid in capital. Subsequent to the IPO, all of these common stock warrants were net exercised into 107,790 shares of common stock. There are no convertible preferred stock warrants or common stock warrants outstanding as of December 31, 2020.

Stock-based Compensation

Stock-based Compensation	12 Months Ended
	Dec. 31, 2020
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock-based Compensation	Note 8. Stock-based compensation Total stock-based compensation is as follows: Year Ended December 31, 2020 2019 2018 (in thousands) Cost of revenue $ 60 $ 16 $ 2 Research and development 822 232 29 Sales and marketing 1,629 188 25 General and administrative 2,578 903 393 Total stock-based compensation $ 5,089 $ 1,339 $ 449 Stock-based compensation costs capitalized as part of capitalized software costs was $0.2 million during the year ended December 31, 2020. No such costs were capitalized during the years ended December 31, 2019 and 2018. Stock-based compensation includes the impact of the Company repricing its stock options in August 2020 by canceling 1,574,243 option grants with a per share exercise price higher than $2.55 in exchange for 1,574,243 new option grants at an exercise price of $2.55 per share. Except for the change in exercise price, the new options had the same terms and conditions as the original options, including the contractual term, vesting schedule and the vesting start date. The total amount of stock-based compensation associated with the repricing is $1.2 million. During the year ended December 31, 2020, the Company recognized $0.5 million of stock-based compensation associated with the repricing, of which $0.3 million relates to options that were already vested on the date of modification. As of December 31, 2020, the Company has unrecognized stock-based compensation related to the repricing of $0.7 million to be expensed over the remaining vesting term of the new options. Determination of fair value The estimated grant-date fair value of the Company’s stock-based awards was calculated using the Black-Scholes option pricing model, based on the following assumptions: Year ended December 31, Valuation assumptions: 2020 2019 2018 Expected volatility 60%-71% 58%-60% 23%-27% Expected term 5.1-7.0 years 5.0-10.0 years 5.5-10.0 years Risk-free interest rate 0.23%-1.20% 1.46%-2.51% 2.46%-3.19% Dividend yield — — — The fair value of each stock option grant was determined by the Company using the methods and assumptions discussed below. Each of these inputs is subjective and generally requires significant judgment and estimation by management. Expected term —The expected term represents the period that stock-based awards are expected to be outstanding. The Company’s historical share option exercise information is limited due to a lack of sufficient data points and does not provide a reasonable basis upon which to estimate an expected term for employee options. The expected term for employee option grants is therefore determined using the simplified method, which is the midpoint between the vesting period and the contractual life. The expected term for nonemployee options is the contractual term. Expected volatility —The expected volatility was derived from the historical stock volatilities of comparable peer public companies within the Company’s industry that are considered to be comparable to the Company’s business over a period equivalent to the expected term of the stock-based awards as there has been no trading history of the Company’s common stock prior to its IPO and limited trading history subsequent to its IPO. Risk-free interest rate —The risk-free interest rate is based on the U.S. Treasury yield curve in effect at the date of grant for zero-coupon U.S. Treasury notes with maturities approximately equal to the stock-based awards’ expected term. Expected dividend yield —The expected dividend yield is zero as the Company has not paid nor does it anticipate paying any dividends on its common stock in the foreseeable future. Fair value of common stock — For grants prior to the Company’s IPO in October 2020, the fair value of common stock underlying share-based awards was estimated on each grant date by the Company’s board of directors. In order to determine the fair value of the Company’s common stock underlying option grants, the board of directors considered, among other things, valuations of common stock prepared by an unrelated third-party valuation firm in accordance with the guidance provided by the American Institute of Certified Public Accountants Practice Guide, Valuation of Privately-Held-Company Equity Securities Issued as Compensation. For all grants subsequent to the IPO in October 2020, the fair value of common stock was determined by using the closing price per share of common stock as reported on the Nasdaq Global Select Market. Equity incentive plans In November 2010, the Company adopted the 2010 Equity Incentive Plan (the “2010 Plan”) under which the Board had the authority to issue stock options to employees, directors and consultants. In October 2020, the Company’s board of directors and stockholders adopted and approved the 2020 Equity Incentive Plan, (the “2020 Plan”). The Company’s 2010 Stock Plan was terminated in connection with the IPO and no further grants will be made under the 2010 Plan from the date that the 2020 Plan became effective. A total of 4,687,685 shares of common stock were initially reserved for issuance under the 2020 Plan, which includes 9,940 shares that remained available for issuance under the 2010 Plan. There are 4,593,583 shares available for issuance under the 2020 Plan as of December 31, 2020. Activity under the 2010 Plan and 2020 Plan is set forth below: Number of shares Weighted average exercise price Weighted average remaining contractual term Aggregate intrinsic value (in years) (in thousands) Balance December 31, 2019 3,474,052 $ 2.93 8.55 $ 16,440 Grants 3,972,421 3.81 Exercises (646,851 ) 1.82 Cancelled/forfeited (330,778 ) 3.71 Balance December 31, 2020 6,468,844 $ 2.78 8.77 $ 271,944 Vested and exercisable at December 31, 2020 1,609,444 $ 1.88 7.50 $ 75,312 The weighted-average grant-date fair value of options granted during the years ended December 31, 2020, 2019 and 2018 were $3.22, $2.85 and $0.39 per share, respectively. The aggregate intrinsic values of options outstanding and vested and exercisable were calculated as the difference between the exercise price of the options and the fair value of the Company’s common stock. The intrinsic value of options exercised during the year ended December 31, 2020 was $5.0 million, and was immaterial during the years ended December 31, 2019 and 2018. As of December 31, 2020, total unrecognized stock-based compensation related to outstanding unvested stock options was $15.1 million, which the Company expects to recognize over a remaining weighted-average period of 2.9 years. Performance awards In August 2020, the Company granted 1,129,270 stock options with both service-based vesting conditions and performance-based vesting conditions based on operating results. The performance-based conditions terminated upon the closing of the IPO in October 2020 per the original terms of the awards, with the service-based vesting conditions remaining in effect. The Company recorded $1.1 million in stock-based compensation during the year ended December 31, 2020 related to these awards. In September 2020, the Company granted 212,489 stock options with both service-based and performance-based vesting conditions. The grant date fair value of the awards was $0.7 million. In October 2020, the performance-based vesting condition was satisfied upon the completion of the IPO. The Company recorded $0.2 million in related stock-based compensation during the year ended December 31, 2020, which includes $0.1 million of stock-based compensation upon the IPO for the service period rendered from the date of grant through the completion of the IPO. Restricted stock units Restricted stock units (“RSUs”) granted under the 2020 Plan are share awards that entitle the holder to receive freely tradable shares of the Company’s common stock upon vesting. The RSUs cannot be transferred and the awards are subject to forfeiture if the holder’s service to the Company terminates prior to the release of the vesting restrictions. The fair value of the RSUs is equal to the closing price of the Company’s common stock on the grant date. In December 2020, the Company granted 8,270 RSUs at a grant-date fair value of $50.70 per share. There were no RSUs granted prior to December 2020. During the year ended December 31, 2020, the Company recorded stock-based compensation of less than $0.1 million related to the RSUs. As of December 31, 2020, there was $0.4 million of total unrecognized compensation cost related to the RSUs that is expected to be recognized over a weighted-average period of 3.87 years. Employee Stock Purchase Plan (ESPP) In October 2020, the Board of Directors and stockholders adopted and approved the 2020 Employee Stock Purchase Plan (the “ESPP”). The Company reserved 726,773 shares of common stock for future issuance under the ESPP. The ESPP provides for consecutive, overlapping 24-month offering periods, which are generally divided into four purchase periods of approximately six months. The offering periods are scheduled to start on the first trading day on or after May 16 and November 16 of each year, with exception of the first offering period which commenced on October 16, 2020, the first trading day after the effective date of the Company’s registration statement, and will end on November 15, 2022. Contributions under the ESPP are generally limited to a maximum of 15% of an employee’s eligible compensation. Each offering period consists of four six-month purchase periods. On each purchase date, which falls on the last date of each purchase period, ESPP participants will purchase shares of common stock at a price per share equal to 85% of the lesser of (1) the fair market value per share of the common stock at the start of the offering period or (2) the fair market value of the common stock on the purchase date. The Company recorded $0.8 million of stock-based compensation related to the ESPP for the year ended December 31, 2020. The fair value of the ESPP shares is estimated using the Black-Scholes option pricing model, based on the following assumptions: Year ended December 31, Valuation assumptions: 2020 Expected volatility 48%-62% Expected term 0.4-1.9 years Risk-free interest rate 0.09%-0.14% Dividend yield —

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2020
Income Tax Disclosure [Abstract]
Income Taxes	Note 9. Income taxes The Company has not recorded an income tax provision for the years ended December 31, 2020, 2019 and 2018 due to its history of operating losses. All loss before income taxes was generated in the United States for the years ended December 31, 2020, 2019 and 2018. Reconciliation of the statutory federal income tax to the Company’s effective tax is as follows: December 31, 2020 2019 2018 (in thousands) Income tax provision at statutory rate $ (8,370 ) $ (9,342 ) $ (7,096 ) State income taxes, net of federal benefit (826 ) (2,350 ) (2,546 ) Change in valuation allowance 8,720 3,064 9,789 Stock-based compensation (621 ) 190 128 Section 382 limitation on net operating loss and credit carryforwards — 9,956 — Research and development tax credits (1,442 ) (1,306 ) (714 ) Change in fair value of warrants 326 79 178 Derivative liability and extinguishment of debt 545 — — Return-to-provision adjustments 1,261 (413 ) (1 ) Other 407 122 262 Total current income tax provision $ — $ — $ — The tax effects of temporary differences and carryforwards that give rise to significant portions of deferred tax assets are as follows: December 31, 2020 2019 2018 (in thousands) Deferred tax assets: Net operating loss carryforwards $ 35,943 $ 29,684 $ 28,044 Depreciation and amortization - — 131 Research and development credits 3,910 2,468 1,345 Accruals and reserves 2,986 1,667 927 Stock-based compensation 589 345 203 Total deferred tax assets 43,428 34,164 30,650 Valuation allowance (42,435 ) (33,714 ) (30,650 ) Deferred tax assets after valuation allowance 993 450 — Deferred tax liabilities (993 ) (450 ) — Net deferred tax assets $ — $ — $ — Due to the uncertainties surrounding the realization of deferred assets through future income, the Company has established a full valuation allowance against its deferred tax assets and, therefore, no benefit has been recognized for the net operating loss and other deferred tax assets. The valuation allowance increased by $8.7 million, $3.1 million and $9.8 million during the years ending December 31, 2020, 2019 and 2018. As of December 31, 2020, the Company had federal net operating loss carryforwards of approximately of which $ million begin to expire in the year 2030 and $ million will carry over indefinitely. The Company also has state net operating loss carryovers of approximately As of December 31, 2020, the Company had research and development credits carryovers for federal income tax purposes of approximately $2.6 million which expire beginning in the year 2031. The Company also has state research and development credit carryforwards of approximately $3.0 million as of December 31, 2020, which do not expire. Utilization of the net operating loss and credit carryforwards will be subject to an annual limitation due to the ownership percentage change limitations provided by the Internal Revenue Code of 1986, as amended, and similar state provisions. The annual limitation may result in the expiration of the net operating loss carryforwards before utilization. In the event the Company has had a change of ownership, utilization of the carryforwards could be restricted. The Company’s net operating loss deferred tax asset was reduced from the prior year as a result of limitation on the utilization of net operating loss carryforwards subject to the Internal Revenue Code Section 382. Uncertain tax positions A reconciliation of the beginning and ending amounts of unrecognized tax benefits is as follows: December 31, 2020 2019 2018 (in thousands) Beginning balance $ 1,058 $ 576 $ 286 Increases related to current year tax positions 618 482 290 Ending balance $ 1,676 $ 1,058 $ 576 If recognized, gross unrecognized tax benefits would not have an impact on the Company’s effective tax rate due to the Company’s full valuation allowance position. While it is often difficult to predict the final outcome of any particular uncertain tax position, the Company does not believe that the amount of gross unrecognized tax benefits will change significantly in the next twelve months. The Company’s income tax returns for all tax years remain open to examination by federal and state taxing authorities due to the taxing authorities’ ability to adjust operating loss carryforwards. The Company has elected to recognize interest and penalties related to uncertain tax positions as a component of the income tax provision. No such expenses were incurred in the years ended December 31, 2020, 2019 and 2018. The Company has not made any accruals for payment of interest related to unrecognized tax benefits.

Net Loss Per Share Attributable

Net Loss Per Share Attributable To Common Stockholders	12 Months Ended
	Dec. 31, 2020
Earnings Per Share [Abstract]
Net Loss Per Share Attributable To Common Stockholders	Note 10. Net loss per share attributable to common stockholders The following outstanding potentially dilutive common stock equivalents have been excluded from the computation of diluted net loss per share for the periods presented due to their anti-dilutive effect: Year ended December 31, 2020 2019 2018 Convertible preferred stock — 13,710,242 13,645,589 Common stock options issued and outstanding 6,468,844 3,474,052 2,181,122 Restricted stock units 8,270 — — Shares issuable pursuant to ESPP 17,865 — — Convertible preferred stock warrants — 73,913 58,913 Total 6,494,979 17,258,207 15,885,624 The following table sets forth the computation of basic and diluted net loss per share attributable to common stockholders: Year ended December 31, 2020 2019 2018 (in thousands, except share and per share amounts) Numerator: Net loss $ (39,855 ) $ (44,486 ) $ (33,793 ) Gain on extinguishment of Series C and Series C-1 convertible preferred stock 9,840 — — Net loss attributable to common stockholders, basic and diluted $ (30,015 ) $ (44,486 ) $ (33,793 ) Denominator: Weighted-average shares used in computing net loss per share attributable to common stockholders, basic and diluted 7,890,375 256,452 225,754 Net income loss per share attributable to common stockholders, basic and diluted $ (3.80 ) $ (173.47 ) $ (149.69 )

Subsequent Events

Subsequent Events	12 Months Ended
	Dec. 31, 2020
Subsequent Events [Abstract]
Subsequent Events	Note 11. Subsequent Events In January and February 2021, the Company granted options to purchase 119,100 shares of its common stock at a weighted-average exercise price of $57.03 per share and 119,100 RSUs at a weighted-average grant-date fair value of $57.03 per share.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2020
Accounting Policies [Abstract]
Basis of Presentation and Principles of Consolidation	Basis of presentation and principles of consolidation The consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”). The consolidated financial statements include the accounts of Eargo, Inc. and its wholly-owned subsidiary. All intercompany balances and transactions have been eliminated.
Use of Estimates	Use of estimates The preparation of consolidated financial statements in conformity with GAAP requires management to make estimates, assumptions, and judgments that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities as of the date of the consolidated financial statements and the reported amounts of revenues and expenses during the reporting period. Significant estimates and assumptions made in the accompanying consolidated financial statements include, but are not limited to, allowance for sales returns, the fair value of lease liabilities, the fair value of equity securities, the fair value of financial instruments, the allowance for doubtful accounts, the net realizable value of inventory, the useful lives of long-lived assets, accrued product warranty reserve, certain other accruals and recoverability of the Company’s net deferred tax assets and the related valuation allowance
Cash And Cash Equivalents and Restricted Cash	Cash, cash equivalents and restricted cash Cash equivalents consist of short-term, highly liquid investments with original maturities of three months or less from the purchase date. Cash equivalents consist primarily of amounts invested in money market accounts and are stated at fair value. As of December 31, 2018, the Company had $0.2 million in an outstanding letter of credit related to its operating lease. The letter of credit was collateralized by a restricted cash deposit account consisting of short-term money market funds. The Company does not have any amounts classified as restricted cash as of December 31, 2020 and 2019. The following table provides a reconciliation of cash, cash equivalents and restricted cash reported within the consolidated balance sheets that sum to the total of the same amounts shown in the consolidated statements of cash flows: Year Ended December 31, 2020 2019 2018 (in thousands) Cash and cash equivalents $ 212,185 $ 13,384 $ 51,051 Restricted cash — — 150 Total cash, cash equivalents, and restricted cash $ 212,185 $ 13,384 $ 51,201
Concentration of Credit Risk	Concentration of credit risk Financial instruments that potentially subject the Company to concentrations of credit risk consist of demand deposit accounts, money market accounts and accounts receivable, including credit card receivables. The Company maintains its cash and cash equivalents, which may, at times, exceed federally insured limits, with financial institutions of high credit standing. As of December 31, 2020, the Company has not experienced any losses on its deposit accounts and money market accounts. As of December 31, 2020, the Company does not believe there is significant financial risk from nonperformance by the issuers of the Company’s deposit accounts and money market accounts. Approximately 45% and 39% of the Company’s gross accounts receivable are related to reimbursement from an insurance company as of December 31, 2020 and 2019, respectively.
Fair Value Measurement	Fair value measurement Fair value is defined as the exchange price that would be received for an asset or paid to transfer a liability, or an exit price, in the principal or most advantageous market for that asset or liability in an orderly transaction between market participants on the measurement date. The Company measures fair value based on a three-level hierarchy of inputs, of which the first two are considered observable and the last unobservable. Unobservable inputs reflect the Company’s own assumptions about current market conditions. The Company maximizes the use of observable inputs, where available, and minimizes the use of unobservable inputs when measuring fair value. The three-level hierarchy of inputs is as follows: Level 1—Observable inputs such as unadjusted, quoted prices in active markets for identical assets or liabilities at the measurement date; Level 2—Observable inputs other than Level 1 prices, such as quoted prices for similar assets or liabilities, quoted prices in markets that are not active, or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities; and Level 3—Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities. To the extent that the valuation is based on models or inputs that are less observable or unobservable in the market, the determination of fair value requires more judgment. Accordingly, the degree of judgment exercised by the Company in determining fair value is greatest for instruments categorized in Level 3. A financial instrument’s level within the fair value hierarchy is based on the lowest level of any input that is significant to the fair value measurement. The carrying amounts reflected in the consolidated balance sheets for cash and cash equivalents, accounts receivable, accounts payable and accrued liabilities approximate their fair values due to their short-term nature. The fair value of the Company’s outstanding term loan is estimated using the net present value of the payments, discounted at an interest rate that is consistent with a market interest rate, which is a Level 2 input. The fair value of the outstanding term loan approximates the carrying amount as the term loan bears a floating rate that approximates the market interest rate. Refer to Note 3 for discussion of certain other financial instruments.
Accounts Receivable, Net	Accounts receivable, net Accounts receivable represents amounts due from third-party institutions for credit card and debit card transactions and trade accounts receivable. Accounts receivable are recorded at invoiced amounts, net of allowances for doubtful accounts. The allowance for doubtful accounts is based on the Company’s assessment of the collectibility of accounts. Management regularly reviews the adequacy of the allowance for doubtful accounts by considering the age of each outstanding invoice, each customer’s expected ability to pay, and the collection history with each customer, when applicable, to determine whether a specific allowance is appropriate. The allowance for doubtful accounts charges are recorded as a component of general and administrative expenses in the consolidated statements of operations and comprehensive loss.
Inventories	Inventories Inventories are stated at the lower of standard cost (which approximates actual cost on a first-in, first-out basis) and net realizable value. Inventory consists of purchased components for producing hearing aid products and accessories and finished goods. Provisions for slow-moving, excess or obsolete inventories are recorded when required to reduce inventory values to their estimated net realizable values based on product life cycle, development plans or quality issues.
Property and Equipment, Net	Property and equipment, net Property and equipment are stated at cost, less accumulated depreciation and amortization. Depreciation and amortization on property and equipment is calculated using the straight-line method over the estimated useful lives of the assets, generally three to five years. Leasehold improvements are amortized using the straight-line method over the shorter of the lease term or the estimated useful life of the asset. When assets are retired or otherwise disposed of, the cost and related accumulated depreciation and amortization are removed from the consolidated balance sheets and any resulting gain or loss is reflected in operations in the period realized. Repairs and maintenance are expensed as incurred.
Capitalized Software Development Costs	Capitalized software development costs The Company capitalizes software purchased for internal use and qualified costs incurred in connection with the development of internal use software. Purchased software consists of software products and licenses, which are amortized over the lesser of their estimated useful life or the contractual term. Internally developed software costs incurred in the preliminary stages of development are expensed as incurred. Once an application has reached the development stage, internal and external direct costs of the development are capitalized until the software is substantially complete and ready for its intended use. The Company also capitalizes costs related to specific upgrades and enhancements when it is probable that the expenditure will result in additional functionality. Internal use software is amortized on a straight-line basis over its estimated useful life, generally three years. Post-implementation activities including training and maintenance are expensed as incurred. Capitalized costs less accumulated amortization are recorded as a component of property and equipment, net on the consolidated balance sheets.
Impairment of Long-lived Assets	Impairment of long-lived assets The Company evaluates its long-lived assets for impairment whenever events or changes in circumstances indicate that the carrying amount of the assets or group of assets may not be fully recoverable. Recoverability is measured by comparing the carrying amount to the future net undiscounted cash flows which the assets are expected to generate. If such assets are considered to be impaired, the impairment to be recognized is measured by the amount by which the carrying amount of the assets exceeds the projected discounted future net cash flows arising from the asset. The Company has not identified any such impairment losses to date.
Leases	Leases The Company adopted Accounting Standards Codification (“ASC”) Topic 842, “ Leases ROU assets represent the Company’s right to use an underlying asset for the lease term and lease liabilities represent the Company’s obligation to make lease payments arising from the lease. Operating lease ROU assets and liabilities are recognized based on the present value of lease payments over the lease term at the commencement date of the lease. ROU assets also include any initial direct costs incurred and any lease payments made at or before the lease commencement date, less any lease incentive received. As the Company’s leases do not provide an implicit interest rate, the Company uses its incremental borrowing rate based on the information available at the commencement date in determining the present value of lease payments. The Company’s lease terms may include options to extend or terminate the lease when it is reasonably certain that the Company will exercise that option. Lease expense for lease payments is recognized on a straight-line basis over the lease term. The Company elected to exclude from its consolidated balance sheet recognition of leases having a term of 12 months or less (short-term leases) and elected to not separate lease components and non-lease components for its real estate leases. The Company’s non-lease components are primarily related to property maintenance, which varies based on future outcomes, and is recognized in rent expense when incurred.
Product Warranty	Product warranty The Company provides a one-year or two-year limited warranty on its hearing aid products and accrues for the estimated future costs of repair or replacement upon shipment of the original product. The warranty expense is accrued as a liability and recorded to cost of revenue and is based upon current and historical information for the cost to repair or replace the product.
Convertible Preferred Stock Warrant Liability	Convertible preferred stock warrant liability The Company accounts for its convertible preferred stock warrants issued in connection with its various financing transactions based upon the characteristics and provisions of the instrument. Convertible preferred stock warrants classified as liabilities are recorded on the consolidated balance sheets at their fair value on the date of issuance and remeasured to fair value at each reporting period, with the changes in fair value recognized as other income (expense), net in the consolidated statements of operations and comprehensive loss. The Company adjusted the liability for changes in the fair value of these warrants until the earlier of the exercise of the warrants, the expiration of the warrants, or until such time as the warrants were no longer considered liability instruments. Upon the closing of the IPO in October 2020, the convertible preferred stock warrants were converted into warrants to purchase common stock and the warrant liabilities were reclassified to additional paid in capital.
Derivative Liability	Derivative liability The Company’s convertible notes issued in 2020 (the “2020 Notes”) contain certain features that meet the definition of embedded derivatives requiring bifurcation from the 2020 Notes as a separate compound financial instrument. The derivative liability is initially measured at fair value on issuance and is subject to remeasurement at each reporting period with changes in fair value recognized in other income (expense), net in the consolidated statements of operations and comprehensive loss. In July 2020, the derivative liability was settled upon the extinguishment of the 2020 Notes. Refer to Note 3 and Note 6 for further discussion.
Revenue Recognition	Revenue recognition The Company’s revenue is generated from the sale of products (hearing aid systems and related accessories) and services (extended warranties). These products and services are primarily sold directly to customers through Eargo website and the Company sales representatives. Under ASC 606, revenue is recognized when promised goods or services are transferred to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services by following a five step process: (i) identify the contract(s) with a customer; (ii) identify the performance obligations in the contract; (iii) determine the transaction price; (iv) allocate the transaction price to the performance obligations in the contract; and (v) recognize revenue when (or as) the entity satisfies a performance obligation. Identify the contract with a customer. The Company generally considers completion of an Eargo sales order (which requires customer acceptance of the Company’s click-through terms and conditions for website sales and authorization of payment through credit card or another form of payment for sales made over the phone) as a customer contract provided that collection is considered probable. For payments that are not made upfront by credit card, the Company assesses customer creditworthiness based on credit checks, payment history, and/or other circumstances. For payments involving insurance payors, the Company validates customer eligibility and reimbursement amounts prior to shipping the product. Identify the performance obligations in the contract . Product performance obligations include hearing aid systems and related accessories and service performance obligations include extended warranty coverage. The Company also offers customers a one-time replacement of certain components of the hearing aid system for a fee (i.e., “loss and damage policy”), which represents an option with material right. However, as the historical redemption rate under the policy has been low, the option is not accounted for as a separate performance obligation. The Company does not assess whether promised goods or services are performance obligations if they are immaterial in the context of the contract with the customer. The Company has elected to treat shipping and handling activities performed after a customer obtains control of products as a fulfillment activity. Determine the transaction price and allocation to performance obligations . The transaction price in the Company’s customer contracts consists of both fixed and variable consideration. Fixed consideration includes amounts to be contractually billed to the customer while variable consideration includes the 45-day right of return that applies to all products. To estimate product returns, the Company analyzes historical return levels, current economic trends, and changes in customer demand. Based on this information, the Company reserves a percentage of product sale revenue and accounts for the estimated impact as a reduction in the transaction price. Allocate the transaction price to the performance obligations in the contract . For contracts that contain multiple performance obligations, the Company allocates the transaction price to the performance obligations on a relative standalone selling price basis. Standalone selling prices are based on multiple factors including, but not limited to historical discounting trends for products and services, gross margin objectives, internal costs, competitor pricing strategies, and industry technology lifecycles. Recognize revenue when or as the Company satisfies a performance obligation . Revenue for products (hearing aid systems and related accessories) is recognized at a point in time, which is generally upon shipment. Revenue for services (extended warranty) is recognized over time on a ratable basis over the warranty period. Contract costs The Company applies the practical expedient to recognize the incremental costs of obtaining a contract as expense when incurred if the amortization period would be one year or less. These incremental costs include processing fees paid to third-party financing vendors, who provide the Company’s customers with the option to finance their purchase. If a customer elects to utilize this service, the Company receives a non-recourse upfront payment for the product sold, less processing fee withheld by the financing vendor. These processing fees are recognized in cost of revenue in the consolidated statements of operations and comprehensive loss as incurred.
Cost of Revenue	Cost of revenue Cost of revenue consists of expenses relating to the cost of finished goods, freight, personnel costs, consumables, warranty costs, transaction fees including processing fees paid to third-party financing vendors, allocated facility overhead costs, depreciation and amortization.
Research and Development	Research and development Research and development expenses consist of personnel costs, travel expenses, tools, prototype materials and product certification and are charged to expense as incurred.
Sales and Marketing	Sales and marketing Sales and marketing expenses consist of personnel costs, travel expenses, consulting fees, public relations costs, direct marketing, advertising and promotional expenses and allocated facility overhead costs. The Company recorded advertising costs, which are expensed as incurred, of $23.6 million, $18.6 million and $12.3 million for the years ended December 31, 2020, 2019 and 2018, respectively.
Share-based Compensation	Stock-based compensation The Company accounts for stock-based payment awards at fair value. The fair value of stock options and purchase rights granted under the employee stock purchase plan are measured using the Black-Scholes option-pricing model. For stock-based awards that vest subject to the satisfaction of a service requirement, the fair value measurement date is the date of grant and the expense is recognized on a straight-line basis over the requisite service period. For stock-based awards with performance-based vesting conditions, the expense is recognized over the vesting period using the accelerated attribution method. The Company accounts for forfeitures as they occur. Prior to the Company’s IPO in October 2020, the Company had not recognized any stock-based compensation associated with grants that vest upon satisfaction of both a service condition and a performance condition that is satisfied upon the closing of the IPO as the performance condition was not considered probable. Upon the closing of the IPO, the Company recorded stock-based compensation using the accelerated attribution method for the service period rendered from the date of grant through the closing of the IPO as the performance condition was achieved.
Income Taxes	Income taxes The Company uses the asset and liability method to account for income taxes. Under this method, deferred tax assets and liabilities are determined based on the differences between the financial statement carrying amounts of existing assets and liabilities and their tax bases. Deferred tax assets and liabilities are measured using enacted tax rates applied to taxable income in the years in which those temporary differences are expected to be recovered or settled. A valuation allowance is established when necessary to reduce deferred tax assets to the amount expected to be realized. Financial statement effects of uncertain tax positions are recognized when it is more-likely-than-not that the position will be sustained upon examination. Interest and penalties related to unrecognized tax benefits are included within the provision for income tax.
Segments	Segments Operating segments are defined as components of an entity for which separate financial information is available and that is regularly reviewed by the Chief Operating Decision Maker (“CODM”) in deciding how to allocate resources to an individual segment and in assessing performance. The Company’s CODM is its Chief Executive Officer. To date, the Company has viewed its operations and manages its business as one operating and reportable segment, with all operations in the United States.
Employee Benefit Plan	Employee benefit plan The Company sponsors a qualified 401(k) defined contribution plan covering eligible employees. Participants may contribute a portion of their annual compensation limited to a maximum annual amount set by the Internal Revenue Service. There have been no employer contributions under this plan to date.
Net Loss per Share Attributable To Common Stockholders	Net loss per share attributable to common stockholders The Company follows the two-class method when computing net loss per share as the Company has issued shares that meet the definition of participating securities. The two-class method determines net loss per share for each class of common and participating securities according to dividends declared or accumulated and participation rights in undistributed earnings. The two-class method requires income available to common stockholders for the period to be allocated between common and participating securities based upon their respective rights to receive dividends as if all income for the period had been distributed. Basic net loss per share attributable to common stockholders is calculated by dividing the net loss attributable to common stockholders by the weighted-average number of shares of common stock outstanding for the period, without consideration for potential dilutive securities. Diluted net loss attributable to common stockholders is computed by adjusting net loss attributable to common stockholders to reallocate undistributed earnings based on the potential impact of dilutive securities. Diluted net loss per share is computed by dividing the net loss by the weighted-average number of common shares and common share equivalents of potentially dilutive securities outstanding for the period. For purposes of the diluted net loss per share calculation, convertible preferred stock, convertible notes, convertible preferred stock warrants and common stock options are considered to be potentially dilutive securities.
Emerging Growth Company Status	Emerging growth company status The Company is an emerging growth company, as defined in the Jumpstart Our Business Startups Act of 2012 (the “JOBS Act”). Under the JOBS Act, emerging growth companies can delay adopting new or revised accounting standards issued subsequent to the enactment of the JOBS Act until such time as those standards apply to private companies. The Company has elected to use this extended transition period for complying with new or revised accounting standards that have different effective dates for public and private companies until the earlier of the date that it (i) is no longer an emerging growth company or (ii) affirmatively and irrevocably opts out of the extended transition period provided in the JOBS Act. As a result, these consolidated financial statements may not be comparable to companies that comply with the new or revised accounting pronouncements as of public company effective dates.
Recently Adopted and Recent Accounting Pronouncements Not Yet Adopted	Recently adopted accounting pronouncements In February 2016, the FASB issued Accounting Standards Update (“ASU”) 2016-02, Leases (Topic 842) which amended existing guidance to require substantially all leases to be recognized by lessees on their balance sheet as a right-of-use (“ROU”) asset and corresponding lease liability, including leases previously accounted for as operating leases. Leases (Topic 840) In August 2018, the FASB issued ASU 2018-13 , Fair Value Measurement (Topic 820): Disclosure Framework—Changes to the Disclosure Requirements for Fair Value Measurement Recent accounting pronouncements not yet adopted In June 2016, the FASB issued ASU 2016-13, Financial Instruments—Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments In December 2019, the FASB issued ASU No. 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2020
Accounting Policies [Abstract]
Reconciliation of Cash, Cash Equivalents and Restricted Cash	The following table provides a reconciliation of cash, cash equivalents and restricted cash reported within the consolidated balance sheets that sum to the total of the same amounts shown in the consolidated statements of cash flows: Year Ended December 31, 2020 2019 2018 (in thousands) Cash and cash equivalents $ 212,185 $ 13,384 $ 51,051 Restricted cash — — 150 Total cash, cash equivalents, and restricted cash $ 212,185 $ 13,384 $ 51,201

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2020
Summary of Financial Assets and Liabilities Measured at Fair Value on Recurring Basis	The following table summarizes the Company’s financial assets and liabilities that were measured at fair value on a recurring basis by level within the fair value hierarchy: December 31, 2019 Level 1 Level 2 Level 3 Total (in thousands) Liabilities: Convertible preferred stock warrant liability $ — $ — $ 396 $ 396
Embedded Derivatives
Summary of Change in Estimated Fair Value of Derivative Liability	The following table provides a summary of the change in the estimated fair value of the Company’s derivative liability: Total (in thousands) Balance — December 31, 2019 $ — Initial fair value of derivative liability 2,879 Change in fair value of derivative liability 206 Extinguishment of derivative liability (3,085 ) Balance — December 31, 2020 $ —
Convertible Preferred Stock Warrant Liability
Summary of Change in Estimated Fair Value of Convertible Preferred Stock Warrant Liability	The following table provides a summary of the change in the estimated fair value of the Company’s convertible preferred stock warrant liability: Total (in thousands) Balance — December 31, 2018 $ 81 Fair value of convertible preferred stock warrants issued in connection with debt financing 41 Change in fair value of warrant liability 274 Balance — December 31, 2019 396 Fair value of convertible preferred stock warrants issued in connection with debt financing 270 Change in fair value of warrant liability 1,265 Conversion of preferred stock warrants to common stock warrants upon the closing of the IPO (1,931 ) Balance — December 31, 2020 $ —
Summary of Fair Value of Convertible Preferred Stock Warrants Converted to Common Stock Warrants upon Closing of IPO Determined Using Following Assumptions	The fair value of the convertible preferred stock warrants, which were converted to common stock warrants upon the closing of the IPO in October 2020, was determined using the following assumptions: December 31, Valuation assumptions: 2020 2019 Expected volatility 67%—71% 43%—67% Expected term 2.17—9.9 years 1.0—8.6 years Risk-free interest rate 0.15%—0.75% 1.59%—1.88% Dividend yield — —

Balance Sheet Components (Table

Balance Sheet Components (Tables)	12 Months Ended
	Dec. 31, 2020
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Summary of Inventories	Inventories consist primarily of raw materials related to component parts and finished goods. The following is a summary of the Company’s inventories by category: December 31, 2020 2019 (in thousands) Raw materials $ 853 $ 1,115 Finished goods 1,886 1,765 Total inventories $ 2,739 $ 2,880
Summary of Property And Equipment, Net	Property and equipment, net, consists of the following: December 31, 2020 2019 (in thousands) Tools and lab equipment $ 4,426 $ 2,885 Capitalized software 6,744 3,148 Furniture and fixtures 906 906 Leasehold improvements 757 757 Computer and equipment 288 423 13,121 8,119 Less accumulated depreciation and amortization (5,087 ) (2,719 ) Total property and equipment, net $ 8,034 $ 5,400
Summary of Accrued Expenses	Accrued expenses consist of the following: December 31, 2020 2019 (in thousands) Allowance for sales returns $ 4,326 $ 3,759 Accrued compensation 5,861 2,739 Accrued vendor costs 751 2,776 Refunds due to customers 581 215 Accrued warranty reserve 2,390 450 Total accrued expenses $ 13,909 $ 9,939
Summary of Allowance for Doubtful Accounts	The allowance for doubtful accounts consists of the following activity: Year ended December 31, 2020 2019 2018 (in thousands) Allowance for doubtful accounts, beginning balance $ 225 $ — $ — Charged to expense 2,352 225 — Accounts written off, net of recoveries (709 ) — — Allowance for doubtful accounts, ending balance $ 1,868 $ 225 $ —
Summary of Allowance for Sales Returns	The allowance for sales returns consists of the following activity: Year ended December 31, 2020 2019 2018 (in thousands) Allowance for sales returns, beginning balance $ 3,759 $ 2,713 $ 1,198 Charged to revenue 22,676 17,739 17,848 Utilization of allowance for sales returns (22,109 ) (16,693 ) (16,333 ) Allowance for sales returns, ending balance $ 4,326 $ 3,759 $ 2,713
Summary of Accrued Warranty Reserve	The accrued warranty reserve consists of the following activity: Year ended December 31, 2020 2019 2018 (in thousands) Accrued warranty reserve, beginning balance $ 450 $ 53 $ 39 Charged to cost of revenue 3,178 1,589 57 Utilization of accrued warranty reserve (1,238 ) (1,192 ) (43 ) Accrued warranty reserve, ending balance $ 2,390 $ 450 $ 53

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2020
Commitments And Contingencies Disclosure [Abstract]
Schedule of Undiscounted Future Minimum Lease Payments Due under Non-cancelable Operating Leases	As of December 31, 2020, undiscounted future minimum lease payments due under the non-cancelable operating leases are as follows: Operating leases (in thousands) 2021 $ 1,074 2022 167 Total minimum future lease payments 1,241 Present value adjustment for minimum lease commitments (45 ) Total lease liability $ 1,196

Debt Obligations (Tables)

Debt Obligations (Tables)	12 Months Ended
	Dec. 31, 2020
Debt Disclosure [Abstract]
Schedule of Balance of Term Loan	The balance of the term loans is as follows: December 31, 2020 2019 (in thousands) Principal value of long-term debt $ 15,000 $ 12,000 Net of debt discount and accretion of final payment (163 ) 246 Long-term debt, current and noncurrent 14,837 12,246 Less: Long-term debt, current portion — (4,800 ) Long-term debt, noncurrent portion $ 14,837 $ 7,446
Schedule of Future Minimum Payments	Future minimum payments of principal and estimated payments of interest on the Company’s outstanding variable rate borrowings as of December 31, 2020 are as follows: Total (in thousands) 2021 $ 646 2022 3,950 2023 7,038 2024 6,028 Total future payments 17,662 Less amounts representing interest (1,724 ) Less final payment (938 ) Total principal amount of term loan payments $ 15,000

Convertible Preferred Stock a_2

Convertible Preferred Stock and Stockholders Equity (Deficit) (Tables)	12 Months Ended
	Dec. 31, 2020
Temporary Equity Disclosure [Abstract]
Summary of Convertible Preferred Stock	Preferred stock warrants

Stock-based Compensation (Table

Stock-based Compensation (Tables)	12 Months Ended
	Dec. 31, 2020
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Summary of Total Stock-based Compensation	Total stock-based compensation is as follows: Year Ended December 31, 2020 2019 2018 (in thousands) Cost of revenue $ 60 $ 16 $ 2 Research and development 822 232 29 Sales and marketing 1,629 188 25 General and administrative 2,578 903 393 Total stock-based compensation $ 5,089 $ 1,339 $ 449
Assumptions used in Estimating Grant-Date Fair Value of Stock-based Awards Using Black-Scholes Option Pricing Model	The estimated grant-date fair value of the Company’s stock-based awards was calculated using the Black-Scholes option pricing model, based on the following assumptions: Year ended December 31, Valuation assumptions: 2020 2019 2018 Expected volatility 60%-71% 58%-60% 23%-27% Expected term 5.1-7.0 years 5.0-10.0 years 5.5-10.0 years Risk-free interest rate 0.23%-1.20% 1.46%-2.51% 2.46%-3.19% Dividend yield — — —
Summary of Activity under the 2010 Plan and 2020 Plan	Activity under the 2010 Plan and 2020 Plan is set forth below: Number of shares Weighted average exercise price Weighted average remaining contractual term Aggregate intrinsic value (in years) (in thousands) Balance December 31, 2019 3,474,052 $ 2.93 8.55 $ 16,440 Grants 3,972,421 3.81 Exercises (646,851 ) 1.82 Cancelled/forfeited (330,778 ) 3.71 Balance December 31, 2020 6,468,844 $ 2.78 8.77 $ 271,944 Vested and exercisable at December 31, 2020 1,609,444 $ 1.88 7.50 $ 75,312
Fair Value of ESPP Shares Estimated Using Black-Scholes Option Pricing Model	The fair value of the ESPP shares is estimated using the Black-Scholes option pricing model, based on the following assumptions: Year ended December 31, Valuation assumptions: 2020 Expected volatility 48%-62% Expected term 0.4-1.9 years Risk-free interest rate 0.09%-0.14% Dividend yield —

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2020
Income Tax Disclosure [Abstract]
Schedule of Reconciliation of Statutory Federal Income Tax to Effective Tax	Reconciliation of the statutory federal income tax to the Company’s effective tax is as follows: December 31, 2020 2019 2018 (in thousands) Income tax provision at statutory rate $ (8,370 ) $ (9,342 ) $ (7,096 ) State income taxes, net of federal benefit (826 ) (2,350 ) (2,546 ) Change in valuation allowance 8,720 3,064 9,789 Stock-based compensation (621 ) 190 128 Section 382 limitation on net operating loss and credit carryforwards — 9,956 — Research and development tax credits (1,442 ) (1,306 ) (714 ) Change in fair value of warrants 326 79 178 Derivative liability and extinguishment of debt 545 — — Return-to-provision adjustments 1,261 (413 ) (1 ) Other 407 122 262 Total current income tax provision $ — $ — $ —
Schedule of Tax Effects of Temporary Differences and Carryforwards of Significant Portions of Deferred Tax Assets	The tax effects of temporary differences and carryforwards that give rise to significant portions of deferred tax assets are as follows: December 31, 2020 2019 2018 (in thousands) Deferred tax assets: Net operating loss carryforwards $ 35,943 $ 29,684 $ 28,044 Depreciation and amortization - — 131 Research and development credits 3,910 2,468 1,345 Accruals and reserves 2,986 1,667 927 Stock-based compensation 589 345 203 Total deferred tax assets 43,428 34,164 30,650 Valuation allowance (42,435 ) (33,714 ) (30,650 ) Deferred tax assets after valuation allowance 993 450 — Deferred tax liabilities (993 ) (450 ) — Net deferred tax assets $ — $ — $ —
Schedule of Reconciliation of Unrecognized Tax Benefits	A reconciliation of the beginning and ending amounts of unrecognized tax benefits is as follows: December 31, 2020 2019 2018 (in thousands) Beginning balance $ 1,058 $ 576 $ 286 Increases related to current year tax positions 618 482 290 Ending balance $ 1,676 $ 1,058 $ 576

Net Loss Per Share Attributab_2

Net Loss Per Share Attributable To Common Stockholders (Tables)	12 Months Ended
	Dec. 31, 2020
Earnings Per Share [Abstract]
Summary of Outstanding Potentially Dilutive Common Stock Equivalents Excluded from Calculation of Diluted Net Loss Per Share	The following outstanding potentially dilutive common stock equivalents have been excluded from the computation of diluted net loss per share for the periods presented due to their anti-dilutive effect: Year ended December 31, 2020 2019 2018 Convertible preferred stock — 13,710,242 13,645,589 Common stock options issued and outstanding 6,468,844 3,474,052 2,181,122 Restricted stock units 8,270 — — Shares issuable pursuant to ESPP 17,865 — — Convertible preferred stock warrants — 73,913 58,913 Total 6,494,979 17,258,207 15,885,624
Computation of Basic And Diluted Net Loss Per Share Attributable to Common Stockholders	The following table sets forth the computation of basic and diluted net loss per share attributable to common stockholders: Year ended December 31, 2020 2019 2018 (in thousands, except share and per share amounts) Numerator: Net loss $ (39,855 ) $ (44,486 ) $ (33,793 ) Gain on extinguishment of Series C and Series C-1 convertible preferred stock 9,840 — — Net loss attributable to common stockholders, basic and diluted $ (30,015 ) $ (44,486 ) $ (33,793 ) Denominator: Weighted-average shares used in computing net loss per share attributable to common stockholders, basic and diluted 7,890,375 256,452 225,754 Net income loss per share attributable to common stockholders, basic and diluted $ (3.80 ) $ (173.47 ) $ (149.69 )

Description of Business - Addit

Description of Business - Additional Information (Details) $ / shares in Units, $ in Thousands	Oct. 20, 2020USD ($)$ / sharesshares	Dec. 31, 2020USD ($)shares	Dec. 31, 2019USD ($)shares	Dec. 31, 2018USD ($)
Description Of Business [Line Items]
Proceeds from issuance of common stock upon initial public offering, net of underwriting discounts and commissions | $		$ 151,156
Convertible preferred stock outstanding		0	11,825,812
Preferred stock outstanding		0	0
Cash and cash equivalents | $		$ 212,185	$ 13,384	$ 51,051
Accumulated deficit | $		$ 199,058	$ 159,203
Common Stock
Description Of Business [Line Items]
Issuance of stock		9,029,629
Conversion of outstanding convertible preferred stock into common stock		28,196,388
Initial Public Offering
Description Of Business [Line Items]
Reverse stock split ratio	3
Initial Public Offering | Common Stock
Description Of Business [Line Items]
Issuance of stock	7,851,852
Conversion of outstanding convertible preferred stock into common stock	28,196,388
Conversion of convertible preferred stock warrants into common stock	137,812
Underwriters' Option | Common Stock
Description Of Business [Line Items]
Issuance of stock	1,177,777
IPO, Including Underwriters' Option | Common Stock
Description Of Business [Line Items]
Offering price per share | $ / shares	$ 18
Proceeds from issuance of common stock upon initial public offering, net of underwriting discounts and commissions | $	$ 148,500
Underwriters’ discounts and commissions | $	11,400
Estimated offering costs | $	$ 2,600

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Additional Information (Details)	Jan. 01, 2020USD ($)	Dec. 31, 2020USD ($)segment	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)
Summary Of Significant Accounting Policies [Line Items]
Restricted cash				$ 150,000
Product warranty limited warranty period		1 year
Advertising costs		$ 23,600,000	$ 18,600,000	12,300,000
Number of operating segment | segment		1
Number of reportable segment | segment		1
Employee benefit plan, employer contributions		$ 0
Operating right-of-use assets	$ 2,200,000	1,079,000
Operating lease liabilities	2,400,000	$ 1,196,000
Deferred rent liability derecognized	$ 200,000
Lease, practical expedients, package	true
ASU 2016-02
Summary Of Significant Accounting Policies [Line Items]
Change in accounting principle, accounting standards update, adoption date		Jan. 1, 2020
Change in accounting principle, accounting standards update, adopted		true
Change in accounting principle, accounting standards update, early adoption		true
ASU 2018-13
Summary Of Significant Accounting Policies [Line Items]
Change in accounting principle, accounting standards update, adoption date		Jan. 1, 2020
Change in accounting principle, accounting standards update, adopted		true
Change in accounting principle, accounting standards update, immaterial effect		true
Internal Use Software
Summary Of Significant Accounting Policies [Line Items]
Estimated useful life		3 years
Minimum
Summary Of Significant Accounting Policies [Line Items]
Useful lives of assets		3 years
Maximum
Summary Of Significant Accounting Policies [Line Items]
Useful lives of assets		5 years
Accounts Receivable | Credit Concentration Risk
Summary Of Significant Accounting Policies [Line Items]
Concentration risk, percentage		45.00%	39.00%
Letter of Credit
Summary Of Significant Accounting Policies [Line Items]
Restricted cash				$ 200,000

Summary of Significant Accoun_5

Summary of Significant Accounting Policies - Reconciliation of Cash, Cash Equivalents and Restricted Cash (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Accounting Policies [Abstract]
Cash and cash equivalents	$ 212,185	$ 13,384	$ 51,051
Restricted cash			150
Total cash, cash equivalents, and restricted cash	$ 212,185	$ 13,384	$ 51,201

Fair Value Measurements - Summa

Fair Value Measurements - Summary of Financial Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) - USD ($)	Dec. 31, 2020	Dec. 31, 2019
Liabilities:
Liabilities	$ 0
Fair Value on Recurring Basis | Convertible Preferred Stock Warrant Liability
Liabilities:
Liabilities		$ 396,000
Fair Value on Recurring Basis | Level 3 | Convertible Preferred Stock Warrant Liability
Liabilities:
Liabilities		$ 396,000

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Details)	Dec. 31, 2020USD ($)
Fair Value Disclosures [Abstract]
Financial assets outstanding	$ 0
Financial liabilities outstanding	$ 0

Fair Value Measurements - Sum_2

Fair Value Measurements - Summary of Change in Estimated Fair Value of Convertible Preferred Stock Warrant Liability (Details) - Convertible Preferred Stock Warrant Liability - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Balance	$ 396	$ 81
Fair value of convertible preferred stock warrants issued in connection with debt financing	270	41
Change in fair value of warrant liability	1,265	274
Conversion of preferred stock warrants to common stock warrants upon the closing of the IPO	$ (1,931)
Balance		$ 396

Fair Value Measurements - Sum_3

Fair Value Measurements - Summary of Fair Value of Convertible Preferred Stock Warrants Converted to Common Stock Warrants upon Closing of IPO Determined Using Following Assumptions (Details) - Convertible Preferred Stock Warrant Liability	Dec. 31, 2020	Dec. 31, 2019
Minimum
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Expected term	2 years 2 months 1 day	1 year
Maximum
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Expected term	9 years 10 months 24 days	8 years 7 months 6 days
Expected Volatility | Minimum
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Warrants measurement input	0.67	0.43
Expected Volatility | Maximum
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Warrants measurement input	0.71	0.67
Risk-Free Interest Rate | Minimum
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Warrants measurement input	0.0015	0.0159
Risk-Free Interest Rate | Maximum
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Warrants measurement input	0.0075	0.0188

Fair Value Measurements - Sum_4

Fair Value Measurements - Summary of Change in Estimated Fair Value of Derivative Liability (Details) - Embedded Derivatives $ in Thousands	12 Months Ended
	Dec. 31, 2020USD ($)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Balance — December 31, 2019	$ 0
Initial fair value of derivative liability	2,879
Change in fair value of derivative liability	206
Extinguishment of derivative liability	(3,085)
Balance — December 31, 2020	$ 0

Balance Sheet Components - Summ

Balance Sheet Components - Summary of Inventories (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Inventory Disclosure [Abstract]
Raw materials	$ 853	$ 1,115
Finished goods	1,886	1,765
Total inventories	$ 2,739	$ 2,880

Balance Sheet Components - Su_2

Balance Sheet Components - Summary of Property And Equipment, Net (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Property Plant And Equipment [Line Items]
Total property and equipment, gross	$ 13,121	$ 8,119
Less accumulated depreciation and amortization	(5,087)	(2,719)
Total property and equipment, net	8,034	5,400
Tools and Lab Equipment
Property Plant And Equipment [Line Items]
Total property and equipment, gross	4,426	2,885
Capitalized Software
Property Plant And Equipment [Line Items]
Total property and equipment, gross	6,744	3,148
Furniture and Fixtures
Property Plant And Equipment [Line Items]
Total property and equipment, gross	906	906
Leasehold Improvements
Property Plant And Equipment [Line Items]
Total property and equipment, gross	757	757
Computer and Equipment
Property Plant And Equipment [Line Items]
Total property and equipment, gross	$ 288	$ 423

Balance Sheet Components - Addi

Balance Sheet Components - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Property Plant And Equipment [Abstract]
Depreciation and amortization expense	$ 2,525	$ 1,528	$ 695
Amortization of capitalized software costs	$ 800	$ 300

Balance Sheet Components - Su_3

Balance Sheet Components - Summary of Accrued Expenses (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Allowance for sales returns	$ 4,326	$ 3,759
Accrued compensation	5,861	2,739
Accrued vendor costs	751	2,776
Refunds due to customers	581	215
Accrued warranty reserve	2,390	450
Total accrued expenses	$ 13,909	$ 9,939

Balance Sheet Components - Su_4

Balance Sheet Components - Summary of Allowance for Doubtful Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Receivables [Abstract]
Allowance for doubtful accounts, balance	$ 225
Charged to expense	2,352	$ 225
Accounts written off, net of recoveries	(709)
Allowance for doubtful accounts, balance	$ 1,868	$ 225

Balance Sheet Components - Su_5

Balance Sheet Components - Summary of Allowance for Sales Returns (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Allowance for sales returns, beginning balance	$ 3,759	$ 2,713	$ 1,198
Charged to revenue	22,676	17,739	17,848
Utilization of allowance for sales returns	(22,109)	(16,693)	(16,333)
Allowance for sales returns, ending balance	$ 4,326	$ 3,759	$ 2,713

Balance Sheet Components - Su_6

Balance Sheet Components - Summary of Accrued Warranty Reserve (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Accrued warranty reserve, beginning balance	$ 450	$ 53	$ 39
Charged to cost of revenue	3,178	1,589	57
Utilization of accrued warranty reserve	(1,238)	(1,192)	(43)
Accrued warranty reserve, ending balance	$ 2,390	$ 450	$ 53

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Jan. 01, 2020
Commitments And Contingencies Disclosure [Abstract]
Operating lease right-of-use assets	$ 1,079	$ 2,200
Operating lease liabilities	$ 1,196	$ 2,400
ROU asset and operating lease liability, weighted-average incremental borrowing rate	7.10%
Operating lease, weighted-average remaining lease term	1 year 1 month 6 days
Operating lease costs	$ 1,300

Commitments and Contingencies_2

Commitments and Contingencies - Schedule of Undiscounted Future Minimum Lease Payments Due under Non-cancelable Operating Leases (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Jan. 01, 2020
Commitments And Contingencies Disclosure [Abstract]
2021	$ 1,074
2022	167
Total minimum future lease payments	1,241
Present value adjustment for minimum lease commitments	(45)
Operating lease liabilities	$ 1,196	$ 2,400

Debt Obligations - Additional I

Debt Obligations - Additional Information (Details) - USD ($)

1 Months Ended

12 Months Ended

Sep. 30, 2020

Aug. 31, 2020

Jul. 31, 2020

May 31, 2020

Mar. 31, 2020

Jun. 30, 2019

Jan. 31, 2019

Dec. 31, 2018

Nov. 30, 2018

Oct. 31, 2018

Jun. 30, 2018

Dec. 31, 2020

Dec. 31, 2019

Dec. 31, 2018

May 03, 2020

Apr. 30, 2020

Debt Instrument [Line Items]

Proceeds from debt financing

$ 15,000,000

$ 5,000,000

$ 7,000,000

Principal value

15,000,000

12,000,000

Debt, final payment as percentage of original aggregate principal amount

6.00%

Interest expense

1,920,000

711,000

424,000

Loss on extinguishment of debt

1,627,000

559,000

Promissory Note | CARES Act | PPP Loan

Debt Instrument [Line Items]

Aggregate principal amount

$ 4,600,000

Repayments on outstanding debt

$ 4,600,000

Interest expense

$ 100,000

Interest rate

1.00%

Debt instrument, frequency of periodic payment

Monthly principal and interest payments

2020 Notes

Debt Instrument [Line Items]

Aggregate principal amount

$ 8,900,000

$ 1,200,000

Maturity period

2021-03

Interest expense

$ 900,000

Interest rate

6.00%

Debt discount

$ 2,900,000

2020 Notes | Other Income (Expense)

Debt Instrument [Line Items]

Loss on extinguishment of debt

$ 1,600,000

2020 Notes | Preferred Stock

Debt Instrument [Line Items]

Debt instrument convert, threshold percentage of equity financing price per share

80.00%

2020 Notes | Common Stock

Debt Instrument [Line Items]

Debt instrument convert, threshold percentage of equity financing price per share

90.00%

Minimum | 2020 Notes

Debt Instrument [Line Items]

Potential proceeds from sale of equity

$ 15,000,000

Series C Convertible Preferred Stock

Debt Instrument [Line Items]

Debt conversion, convertible to preferred stock, conversion price per share

$ 9.0201

Series E Convertible Preferred Stock

Debt Instrument [Line Items]

Debt conversion, convertible to preferred stock, value

$ 12,818,000

Conversion of convertible securities in to stock

1,889,548

Percentage of share price paid by investor in preferred stock financing

80.00%

Share price per share paid by investor in preferred stock financing

$ 6.7836

Series E Convertible Preferred Stock | 2020 Notes

Debt Instrument [Line Items]

Debt conversion, convertible to preferred stock, value

$ 10,100,000

$ 10,300,000

Debt conversion, accrued interest convertible to preferred stock, value

$ 200,000

Conversion of convertible securities in to stock

1,889,548

1,889,548

Debt conversion, convertible to preferred stock, conversion price per share

$ 5.427

2018 Loan Agreement

Debt Instrument [Line Items]

Aggregate principal amount

$ 12,500,000

Proceeds from debt financing

$ 1,000,000

$ 1,000,000

$ 5,000,000

Maturity period

2022-06

Term loans, interest rate terms

The term loans under the 2018 Loan Agreement mature in June 2022, with interest-only monthly payments for a specified period of time. Interest on the term loans accrued at a per annum rate equal to the Wall Street Journal prime rate minus 1.0% with a floor of 0.0%.

2018 Loan Agreement | Series C Convertible Preferred Stock | Silicon Valley Bank

Debt Instrument [Line Items]

Warrants issued to purchase shares of convertible preferred stock

30,173

2018 Loan Agreement | Wall Street Journal Prime Rate

Debt Instrument [Line Items]

Term loans, interest rate

1.00%

Term loans, floor rate

0.00%

Amendments 2018 Loan Agreement

Debt Instrument [Line Items]

Aggregate principal amount

$ 20,000,000

Proceeds from debt financing

$ 15,000,000

$ 5,000,000

Maturity period

2024-09

2022-06

2020-01

Term loans, interest rate terms

The term loan under the Third Amendment matures in September 2024 with interest-only monthly payments until January 2022, which was extended to July 2022 upon the completion of the Company’s IPO in October 2020. The term loan accrues interest at a per annum rate equal to the Wall Street Journal prime rate plus 1.0% (4.25% as of December 31, 2020) and includes a final payment fee equal to 6.25% of the original aggregate principal amount.

Principal value

$ 12,000,000

Repayments on outstanding debt

$ 10,200,000

Final payment fee

9,500,000

Payments on existing term loan

$ 700,000

Debt, final payment as percentage of original aggregate principal amount

6.25%

Interest expense

$ 1,000,000

$ 700,000

$ 100,000

Effective interest rate

7.12%

Amendments 2018 Loan Agreement | Series C Convertible Preferred Stock | Silicon Valley Bank

Debt Instrument [Line Items]

Warrants issued to purchase shares of convertible preferred stock

14,999

Amendments 2018 Loan Agreement | Series E Convertible Preferred Stock | Silicon Valley Bank

Debt Instrument [Line Items]

Warrants issued to purchase shares of convertible preferred stock

53,487

Amendments 2018 Loan Agreement | Wall Street Journal Prime Rate

Debt Instrument [Line Items]

Term loans, interest rate

1.00%

4.25%

Debt Obligations - Schedule of

Debt Obligations - Schedule of Balance of Term Loan (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Debt Disclosure [Abstract]
Principal value	$ 15,000	$ 12,000
Net of debt discount and accretion of final payment	(163)	246
Long-term debt, current and noncurrent	14,837	12,246
Less: Long-term debt, current portion		(4,800)
Long-term debt, noncurrent portion	$ 14,837	$ 7,446

Debt Obligations - Schedule o_2

Debt Obligations - Schedule of Future Minimum Payments (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Debt Disclosure [Abstract]
2021	$ 646
2022	3,950
2023	7,038
2024	6,028
Total future payments	17,662
Less amounts representing interest	(1,724)
Less final payment	(938)
Total principal amount of term loan payments	$ 15,000	$ 12,000

Convertible Preferred Stock a_3

Convertible Preferred Stock and Stockholders Equity - Additional Information (Details) - USD ($)	1 Months Ended	2 Months Ended	12 Months Ended
	Jul. 31, 2020	Aug. 31, 2020	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Oct. 20, 2020	Oct. 19, 2020
Temporary Equity [Line Items]
Common stock, shares authorized			110,000,000	55,190,000
Common stock, par value			$ 0.0001	$ 0.0001
Undesignated preferred stock shares authorized			5,000,000	0
Preferred stock, par value			$ 0.0001	$ 0.0001
Proceeds from convertible preferred stock issuance, net of issuance costs			$ 67,867,000	$ 865,000	$ 72,407,000
Net carrying value				$ 152,880,000
Exercise of common stock warrants			$ 107,790
Convertible preferred stock outstanding			0	11,825,812
Common stock warrants outstanding			0
Common Stock
Temporary Equity [Line Items]
Convertible preferred stock converted into common stock						28,196,388
Series E Convertible Preferred Stock
Temporary Equity [Line Items]
Issuance of stock		10,513,921	10,513,921
Shares issued price per share		$ 6.7836
Proceeds from convertible preferred stock issuance, net of issuance costs		$ 67,300,000
Debt conversion, convertible to preferred stock, value			$ 12,818,000
Conversion of convertible securities in to stock			1,889,548
Series E Convertible Preferred Stock | 2020 Notes
Temporary Equity [Line Items]
Debt conversion, convertible to preferred stock, value	$ 10,100,000		$ 10,300,000
Conversion of convertible securities in to stock	1,889,548		1,889,548
Debt conversion, convertible to preferred stock, conversion price per share	$ 5.427
Series A convertible preferred stock
Temporary Equity [Line Items]
Debt conversion, convertible to preferred stock, conversion price per share			$ 27.87
Net carrying value				$ 16,130,000
Convertible preferred stock outstanding				423,713
Series A convertible preferred stock | Anti-dilution Adjustments Effect
Temporary Equity [Line Items]
Debt conversion, convertible to preferred stock, conversion price per share			19.599
Series B convertible preferred stock
Temporary Equity [Line Items]
Debt conversion, convertible to preferred stock, conversion price per share			60.60
Net carrying value				$ 2,229,000
Convertible preferred stock outstanding				27,652
Series B convertible preferred stock | Anti-dilution Adjustments Effect
Temporary Equity [Line Items]
Debt conversion, convertible to preferred stock, conversion price per share			39.6303
Series B-1 convertible preferred stock
Temporary Equity [Line Items]
Debt conversion, convertible to preferred stock, conversion price per share			9.0201
Net carrying value				$ 22,871,000
Convertible preferred stock outstanding				838,892
Series B-1 convertible preferred stock | Anti-dilution Adjustments Effect
Temporary Equity [Line Items]
Debt conversion, convertible to preferred stock, conversion price per share			8.0625
Series C Convertible Preferred Stock
Temporary Equity [Line Items]
Issuance of stock					2,381,336
Debt conversion, convertible to preferred stock, conversion price per share			9.0201
Net carrying value				$ 33,418,000
Convertible preferred stock outstanding				3,725,354
Series C Convertible Preferred Stock | Anti-dilution Adjustments Effect
Temporary Equity [Line Items]
Debt conversion, convertible to preferred stock, conversion price per share			8.0625
Series C-1 convertible preferred stock
Temporary Equity [Line Items]
Debt conversion, convertible to preferred stock, conversion price per share			7.2162
Net carrying value				$ 26,280,000
Convertible preferred stock outstanding				2,913,490
Series C-1 convertible preferred stock | Anti-dilution Adjustments Effect
Temporary Equity [Line Items]
Debt conversion, convertible to preferred stock, conversion price per share			6.9585
Series D Convertible Preferred Stock
Temporary Equity [Line Items]
Issuance of stock				64,653	3,832,058
Debt conversion, convertible to preferred stock, conversion price per share			13.374
Net carrying value				$ 51,952,000
Convertible preferred stock outstanding				3,896,711
Series D Convertible Preferred Stock | Anti-dilution Adjustments Effect
Temporary Equity [Line Items]
Debt conversion, convertible to preferred stock, conversion price per share			$ 10.7271
Series C and Series C-1 Convertible Preferred Stock
Temporary Equity [Line Items]
Gain on extinguishment of Series C and Series C-1 convertible preferred stock			$ 9,800,000
Net carrying value			59,700,000
Fair value			$ 49,900,000
Amended and Restated IPO
Temporary Equity [Line Items]
Common stock, shares authorized							300,000,000
Common stock, par value							$ 0.0001
Undesignated preferred stock shares authorized							5,000,000
Preferred stock, par value							$ 0.0001
Initial Public Offering | Common Stock
Temporary Equity [Line Items]
Warrants issued to purchase shares of convertible preferred stock						137,812

Convertible Preferred Stock a_4

Convertible Preferred Stock and Stockholders Equity - Summary of Convertible Preferred Stock (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Temporary Equity [Line Items]
Shares authorized	0	36,269,166
Shares issued	0	11,825,812
Shares outstanding	0	11,825,812
Net carrying value		$ 152,880
Aggregate liquidation preference		$ 148,489
Series A convertible preferred stock
Temporary Equity [Line Items]
Shares authorized		1,283,000
Shares issued		423,713
Shares outstanding		423,713
Net carrying value		$ 16,130
Aggregate liquidation preference		$ 16,271
Series B convertible preferred stock
Temporary Equity [Line Items]
Shares authorized		83,000
Shares issued		27,652
Shares outstanding		27,652
Net carrying value		$ 2,229
Aggregate liquidation preference		$ 2,473
Series B-1 convertible preferred stock
Temporary Equity [Line Items]
Shares authorized		2,540,000
Shares issued		838,892
Shares outstanding		838,892
Net carrying value		$ 22,871
Aggregate liquidation preference		$ 23,003
Series C Convertible Preferred Stock
Temporary Equity [Line Items]
Shares authorized		11,284,680
Shares issued		3,725,354
Shares outstanding		3,725,354
Net carrying value		$ 33,418
Aggregate liquidation preference		$ 33,603
Series C-1 convertible preferred stock
Temporary Equity [Line Items]
Shares authorized		8,740,486
Shares issued		2,913,490
Shares outstanding		2,913,490
Net carrying value		$ 26,280
Aggregate liquidation preference		$ 21,024
Series D Convertible Preferred Stock
Temporary Equity [Line Items]
Shares authorized		12,338,000
Shares issued		3,896,711
Shares outstanding		3,896,711
Net carrying value		$ 51,952
Aggregate liquidation preference		$ 52,115

Stock-based Compensation - Summ

Stock-based Compensation - Summary of Total Stock-based Compensation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation	$ 5,089	$ 1,339	$ 449
Cost of Revenue
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation	60	16	2
Research and Development
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation	822	232	29
Sales and Marketing
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation	1,629	188	25
General and Administrative
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation	$ 2,578	$ 903	$ 393

Stock-based Compensation - Addi

Stock-based Compensation - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended				11 Months Ended	12 Months Ended
	Dec. 31, 2020	Oct. 31, 2020	Sep. 30, 2020	Aug. 31, 2020	Nov. 30, 2020	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation costs capitalized						$ 203	$ 0	$ 0
Stock options canceled				1,574,243
Options granted				1,574,243
Options granted, exercise price				$ 2.55
Total stock-based compensation						5,089	$ 1,339	$ 449
Unrecognized stock-based compensation	$ 700					$ 700
2020 Equity Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock reserved for issuance	4,687,685					4,687,685
Remaining number of shares available for grant	4,593,583					4,593,583
2010 Equity Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Remaining number of shares available for grant	9,940					9,940
2010 Plan and 2020 Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock options canceled						330,778
Options granted						3,972,421
Options granted, exercise price						$ 3.81
Weighted-average grant-date fair value of options granted						$ 3.22	$ 2.85	$ 0.39
Options, exercised, intrinsic value						$ 5,000
Unrecognized stock-based compensation related to outstanding unvested stock options	$ 15,100					$ 15,100
Unrecognized stock-based compensation related to outstanding unvested stock options, period of recognition						2 years 10 months 24 days
2020 Employee Stock Purchase Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock-based compensation						$ 800
Common stock reserved for issuance		726,773
Employees Eligible Compensation Maximum Percentage		15.00%
Purchase shares of common stock at price per share equal to lesser		85.00%
Stock Option Repricing
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock-based compensation				$ 1,200		500
Stock Option
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock-based compensation						300
Service-Based and Performance-Based Vesting Conditions
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Options granted			212,489	1,129,270
Total stock-based compensation						1,100
Share-based compensation, options grants in period, grant date fair value			$ 700
Performance-Based Vesting Conditions
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock-based compensation						$ 200
Performance-Based Vesting Conditions | Initial Public Offering
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock-based compensation		$ 100
Restricted Stock Units (RSUs) | 2020 Employee Stock Purchase Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized stock-based compensation related to outstanding unvested stock options, period of recognition						3 years 10 months 13 days
Shares granted	8,270				0
Grant date fair value	$ 50.70
Unrecognized compensation cost related to the RSUs	$ 400					$ 400
Minimum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock options, per share exercise price				$ 2.55
Maximum | Restricted Stock Units (RSUs) | 2020 Employee Stock Purchase Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock-based compensation						$ 100

Stock-based Compensation - Assu

Stock-based Compensation - Assumptions used in Estimating Grant-Date Fair Value of Stock-based Awards Using Black-Scholes Option Pricing Model (Details)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Valuation assumptions:
Expected volatility, Minimum	60.00%	58.00%	23.00%
Expected volatility, Maximum	71.00%	60.00%	27.00%
Risk-free interest rate, Minimum	0.23%	1.46%	2.46%
Risk-free interest rate, Maximum	1.20%	2.51%	3.19%
Minimum
Valuation assumptions:
Expected term	5 years 1 month 6 days	5 years	5 years 6 months
Maximum
Valuation assumptions:
Expected term	7 years	10 years	10 years

Stock-based Compensation - Su_2

Stock-based Compensation - Summary of Activity under the 2010 Plan and 2020 Plan (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended	12 Months Ended
	Aug. 31, 2020	Dec. 31, 2020	Dec. 31, 2019
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares, Grants	1,574,243
Number of shares, Cancelled/forfeited	(1,574,243)
Weighted average exercise price, Grants	$ 2.55
2010 Plan and 2020 Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares, Balance		3,474,052
Number of shares, Grants		3,972,421
Number of shares, Exercises		(646,851)
Number of shares, Cancelled/forfeited		(330,778)
Number of shares, Balance		6,468,844	3,474,052
Number of shares, Vested and exercisable		1,609,444
Weighted average exercise price, Balance		$ 2.93
Weighted average exercise price, Grants		3.81
Weighted average exercise price, Exercises		1.82
Weighted average exercise price, Cancelled/forfeited		3.71
Weighted average exercise price, Balance		2.78	$ 2.93
Weighted average exercise price, Vested and exercisable		$ 1.88
Weighted average remaining contractual term, Balance		8 years 9 months 7 days	8 years 6 months 18 days
Weighted average remaining contractual term, Vested and exercisable		7 years 6 months
Aggregate intrinsic value, Balance		$ 271,944	$ 16,440
Aggregate intrinsic value, Vested and exercisable		$ 75,312

Stock-based Compensation - Fair

Stock-based Compensation - Fair Value of ESPP Shares Estimated Using Black-Scholes Option Pricing Model (Details)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected volatility, Minimum	60.00%	58.00%	23.00%
Expected volatility, Maximum	71.00%	60.00%	27.00%
Risk-free interest rate, Minimum	0.23%	1.46%	2.46%
Risk-free interest rate, Maximum	1.20%	2.51%	3.19%
Minimum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected term	5 years 1 month 6 days	5 years	5 years 6 months
Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected term	7 years	10 years	10 years
2020 Employee Stock Purchase Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected volatility, Minimum	48.00%
Expected volatility, Maximum	62.00%
Risk-free interest rate, Minimum	0.09%
Risk-free interest rate, Maximum	0.14%
2020 Employee Stock Purchase Plan | Minimum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected term	4 months 24 days
2020 Employee Stock Purchase Plan | Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected term	1 year 10 months 24 days

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Operating Loss Carryforwards [Line Items]
Income tax provision	$ 0	$ 0	$ 0
Increase in valuation allowance	8,700,000	3,100,000	9,800,000
Unrecognized tax benefits interest and penalties related to uncertain tax position	0	$ 0	$ 0
Accrual for payment of interest related to unrecognized tax benefits	0
Federal
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards	$ 137,100,000
Operating loss carryforwards expiration year	2030
Net operating loss carryforwards, indefinitely	$ 104,500,000
Net operating loss carryforwards, within expiration year	32,600,000
Federal | Research and Development Credits Carryovers
Operating Loss Carryforwards [Line Items]
Tax credit carryforward amount	$ 2,600,000
Tax credit carryforward expiration year	2031
State
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards	$ 83,300,000
Operating loss carryforwards expiration year	2030
State | Research and Development Credits Carryovers
Operating Loss Carryforwards [Line Items]
Tax credit carryforward amount	$ 3,000,000

Income Taxes - Schedule of Reco

Income Taxes - Schedule of Reconciliation of Statutory Federal Income Tax to Effective Tax (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Income tax provision at statutory rate	$ (8,370,000)	$ (9,342,000)	$ (7,096,000)
State income taxes, net of federal benefit	(826,000)	(2,350,000)	(2,546,000)
Change in valuation allowance	8,720,000	3,064,000	9,789,000
Stock-based compensation	(621,000)	190,000	128,000
Section 382 limitation on net operating loss and credit carryforwards		9,956,000
Research and development tax credits	(1,442,000)	(1,306,000)	(714,000)
Change in fair value of warrants	326,000	79,000	178,000
Derivative liability and extinguishment of debt	545,000
Return-to-provision adjustments	1,261,000	(413,000)	(1,000)
Other	407,000	122,000	262,000
Total current income tax provision	$ 0	$ 0	$ 0

Income Taxes - Schedule of Tax

Income Taxes - Schedule of Tax Effects of Temporary Differences and Carryforwards of Significant Portions of Deferred Tax Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Deferred tax assets:
Net operating loss carryforwards	$ 35,943	$ 29,684	$ 28,044
Depreciation and amortization			131
Research and development credits	3,910	2,468	1,345
Accruals and reserves	2,986	1,667	927
Stock-based compensation	589	345	203
Total deferred tax assets	43,428	34,164	30,650
Valuation allowance	(42,435)	(33,714)	$ (30,650)
Deferred tax assets after valuation allowance	993	450
Deferred tax liabilities	$ (993)	$ (450)

Income Taxes - Schedule of Re_2

Income Taxes - Schedule of Reconciliation of Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Beginning balance	$ 1,058	$ 576	$ 286
Increases related to current year tax positions	618	482	290
Ending balance	$ 1,676	$ 1,058	$ 576

Ne Loss Per Share Attributable

Ne Loss Per Share Attributable To Common Stockholders - Summary of Outstanding Potentially Dilutive Common Stock Equivalents Excluded from Calculation of Diluted Net Loss Per Share (Details) - shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from calculation of diluted net loss per share	6,494,979	17,258,207	15,885,624
Convertible Preferred Stock
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from calculation of diluted net loss per share		13,710,242	13,645,589
Common Stock Options Issued and Outstanding
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from calculation of diluted net loss per share	6,468,844	3,474,052	2,181,122
Restricted Stock Units
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from calculation of diluted net loss per share	8,270
Shares Issuable Pursuant to ESPP
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from calculation of diluted net loss per share	17,865
Convertible Preferred Stock Warrants
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from calculation of diluted net loss per share		73,913	58,913

Net Loss Per Share Attributab_3

Net Loss Per Share Attributable To Common Stockholders - Computation of Basic And Diluted Net Loss Per Share Attributable to Common Stockholders (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Numerator:
Net loss and comprehensive loss	$ (39,855)	$ (44,486)	$ (33,793)
Gain on extinguishment of Series C and Series C-1 convertible preferred stock	9,840
Net loss attributable to common stockholders, basic and diluted	$ (30,015)	$ (44,486)	$ (33,793)
Denominator:
Weighted-average shares used in computing net loss per share attributable to common stockholders, basic and diluted	7,890,375	256,452	225,754
Net income loss per share attributable to common stockholders, basic and diluted	$ (3.80)	$ (173.47)	$ (149.69)

Subsequent Events (Details)

Subsequent Events (Details) - $ / shares	1 Months Ended	2 Months Ended
	Aug. 31, 2020	Feb. 28, 2021
Subsequent Event [Line Items]
Options granted	1,574,243
Options granted, exercise price	$ 2.55
Subsequent Event | Stock Option
Subsequent Event [Line Items]
Options granted		119,100
Options granted, exercise price		$ 57.03
Subsequent Event | Restricted Stock Units (RSUs)
Subsequent Event [Line Items]
Shares granted		119,100
Grant date fair value		$ 57.03