Personalis (PSNL) 10-K 25 Feb 21 2020 FY Annual report Financial data

Document And Entity Information

Document And Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2020	Feb. 19, 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	Personalis, Inc.
Entity Central Index Key	0001527753
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Ex Transition Period	true
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Public Float			$ 247,785,767
Entity Common Stock, Shares Outstanding		43,694,323
Entity Current Reporting Status	Yes
ICFR Auditor Attestation Flag	false
Entity Shell Company	false
Entity File Number	001-38943
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	27-5411038
Entity Address, Address Line One	1330 O’Brien Drive
Entity Address, City or Town	Menlo Park
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	94025
City Area Code	650
Local Phone Number	752-1300
Entity Interactive Data Current	Yes
Document Annual Report	true
Document Transition Report	false
Title of 12(b) Security	Common Stock, par value $0.0001
Trading Symbol	PSNL
Security Exchange Name	NASDAQ
Documents Incorporated by Reference	Part III incorporates information by reference from the Registrant’s definitive proxy statement to be filed with the U.S. Securities and Exchange Commission pursuant to Regulation 14A, not later than 120 days after the end of the fiscal year covered by this Annual Report on Form 10-K, in connection with the Registrant’s 2021 annual meeting of stockholders (the “2021 Proxy Statement”).

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Current assets
Cash and cash equivalents	$ 68,525	$ 55,046
Short-term investments	134,765	73,243
Accounts receivable, net	6,349	3,300
Inventory and other deferred costs	5,639	4,606
Prepaid expenses and other current assets	5,441	3,383
Total current assets	220,719	139,578
Property and equipment, net	11,834	14,106
Operating lease right-of-use assets	10,271	1,845
Other long-term assets	2,018	1,762
Total assets	244,842	157,291
Current liabilities
Accounts payable	8,301	7,337
Accrued and other current liabilities	11,301	6,648
Contract liabilities	21,034	35,977
Total current liabilities	40,636	49,962
Long-term operating lease liabilities	8,541	639
Other long-term liabilities	720
Total liabilities	49,897	50,601
Commitments and Contingencies (Note 12)
Stockholders’ equity
Common stock, $0.0001 par value — 200,000,000 shares authorized; 39,105,548 and 31,243,029 shares issued and outstanding at December 31, 2020 and 2019, respectively	4	3
Additional paid-in capital	376,788	247,282
Accumulated other comprehensive income (loss)	22	(6)
Accumulated deficit	(181,869)	(140,589)
Total stockholders’ equity	194,945	106,690
Total liabilities and stockholders’ equity	$ 244,842	$ 157,291

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Dec. 31, 2020	Dec. 31, 2019
Statement Of Financial Position [Abstract]
Preferred stock, par value	$ 0.0001	$ 0.0001
Preferred stock, shares authorized	10,000,000	10,000,000
Preferred stock, shares issued	0	0
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, shares authorized	200,000,000	200,000,000
Common stock, shares, issued	39,105,548	31,243,029
Common stock, shares, outstanding	39,105,548	31,243,029

CONSOLIDATED STATEMENTS OF OPER

CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Statement [Abstract]
Revenues	$ 78,648	$ 65,207	$ 37,774
Costs and expenses
Costs of revenues	58,534	43,127	25,969
Research and development	28,568	22,418	14,304
Selling, general and administrative	33,692	22,080	11,271
Total costs and expenses	120,794	87,625	51,544
Loss from operations	(42,146)	(22,418)	(13,770)
Interest income	949	1,620	293
Interest expense	(2)	(1,133)	(1,894)
Loss on debt extinguishment		(1,704)	(4,658)
Other income (expense), net	(24)	(1,440)	150
Loss before income taxes	(41,223)	(25,075)	(19,879)
Provision for income taxes	(57)	(9)	(7)
Net loss	$ (41,280)	$ (25,084)	$ (19,886)
Net loss per share, basic and diluted	$ (1.20)	$ (1.39)	$ (6.49)
Weighted-average shares outstanding, basic and diluted	34,374,903	18,011,470	3,063,157

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Statement Of Income And Comprehensive Income [Abstract]
Net loss	$ (41,280)	$ (25,084)	$ (19,886)
Other comprehensive income (loss), net of tax
Foreign currency translation adjustment	12	3	(5)
Change in unrealized gain on available-for-sale debt securities	16	6
Comprehensive loss	$ (41,252)	$ (25,075)	$ (19,891)

CONSOLIDATED STATEMENTS OF REDE

CONSOLIDATED STATEMENTS OF REDEEMABLE CONVERTIBLE PREFERRED STOCK AND STOCKHOLDERS' EQUITY (DEFICIT) - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Loss	Accumulated Deficit	Redeemable Convertible Preferred Stock
Redeemable convertible preferred stock, beginning balance at Dec. 31, 2017						$ 75,995
Redeemable convertible preferred stock, beginning balance, shares at Dec. 31, 2017						16,806,745
Beginning balance at Dec. 31, 2017	$ (92,603)	$ 1	$ 3,025	$ (10)	$ (95,619)
Beginning balance, shares at Dec. 31, 2017		3,051,467
Redeemable convertible preferred stock, ending balance at Dec. 31, 2018	$ 89,404					$ 89,404
Redeemable convertible preferred stock, ending balance, shares at Dec. 31, 2018	18,474,742					18,474,742
Equity component credited to additional paid-in capital upon Convertible Notes modification on May 31, 2018 and August 20, 2018 (see Note 6)	$ 4,690		4,690
Convertible Notes conversion on September 20, 2018 (see Note 6); including issuance of Series C redeemable convertible preferred stock						$ 13,409
Convertible Notes conversion on September 20, 2018 (see Note 6); including issuance of Series C redeemable convertible preferred stock, shares						1,667,997
Proceeds from exercise of stock options	99		99
Proceeds from exercise of stock options, shares		33,840
Stock-based compensation	1,317		1,317
Foreign currency translation adjustment	(5)			(5)
Net loss	(19,886)				(19,886)
Ending balance at Dec. 31, 2018	(106,388)	$ 1	9,131	(15)	(115,505)
Ending balance, shares at Dec. 31, 2018		3,085,307
Issuance of common stock warrants	572		572
Elimination of fractional shares upon reverse stock split (see Note 8)		$ (1)	1
Exercise of common stock warrants	8		8
Exercise of common stock warrants, shares		207,712
Conversion of Series A, B and C redeemable convertible preferred stock to common stock	89,404	$ 2	89,402
Conversion of Series A, B and C redeemable convertible preferred stock to common stock, shares		18,474,703
Conversion of redeemable convertible preferred stock warrants to common stock warrants	2,086		2,086
Proceeds from initial public offering, net of expenses	139,828	$ 1	139,827
Proceeds from initial public offering, net of expenses, shares		9,109,725
Proceeds from exercise of stock options	713		713
Proceeds from exercise of stock options, shares		287,932
Proceeds from Employee Stock Purchase Plan purchases	684		684
Proceeds from Employee Stock Purchase Plan purchases		77,684
Stock-based compensation	4,858		4,858
Foreign currency translation adjustment	3			3
Unrealized gain on available-for-sale debt securities	6			6
Net loss	(25,084)				(25,084)
Ending balance at Dec. 31, 2019	106,690	$ 3	247,282	(6)	(140,589)
Ending balance, shares at Dec. 31, 2019		31,243,029
Redeemable convertible preferred stock, Elimination of fractional shares upon reverse stock split (see Notes 2 and 8)						(39)
Elimination of fractional shares upon reverse stock split (see Notes 2 and 8), shares		(34)
Redeemable convertible preferred stock, Conversion of Series A, B and C redeemable convertible preferred stock to common stock, shares						(18,474,703)
Redeemable convertible preferred stock, Conversion of Series A, B and C redeemable convertible preferred stock to common stock						$ (89,404)
Exercise of common stock warrants, shares		79,772
Proceeds from initial public offering, net of expenses	117,065	$ 1	117,064
Proceeds from initial public offering, net of expenses, shares		6,578,947
Proceeds from exercise of stock options	2,789		2,789
Proceeds from exercise of stock options, shares		908,691
Proceeds from Employee Stock Purchase Plan purchases	1,415		1,415
Proceeds from Employee Stock Purchase Plan purchases		164,164
Stock-based compensation	8,238		8,238
Foreign currency translation adjustment	12			12
Unrealized gain on available-for-sale debt securities	16			16
Net loss	(41,280)				(41,280)
Ending balance at Dec. 31, 2020	$ 194,945	$ 4	$ 376,788	$ 22	$ (181,869)
Ending balance, shares at Dec. 31, 2020		39,105,548
Restricted stock units vested, shares		130,945

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Cash flows from operating activities:
Net loss	$ (41,280)	$ (25,084)	$ (19,886)
Adjustments to reconcile net loss to net cash (used in) provided by operating activities
Depreciation and amortization	5,758	4,748	3,066
Stock-based compensation expense	8,238	4,858	1,317
Noncash operating lease cost	1,409	982
Amortization of premium (discount) on short-term investments	391	(39)
Loss on debt extinguishment		1,704	4,658
Change in fair value of convertible preferred stock warrant liability		1,403	391
Change in fair value of compound derivative instrument			(574)
Accretion of noncash interest and debt reduction		156	1,188
Other	60	466	(5)
Changes in operating assets and liabilities
Accounts receivable	(3,049)	1,069	(2,519)
Inventory and other deferred costs	(1,076)	(1,174)	(2,068)
Prepaid expenses and other current assets	(2,312)	(2,559)	(1,265)
Accounts payable	751	1,398	2,164
Accrued and other current liabilities	3,529	1,971	997
Contract liabilities	(14,942)	(6,920)	18,207
Operating lease liabilities	(850)	(1,048)
Other long-term liabilities	720		(99)
Net cash (used in) provided by operating activities	(42,653)	(18,069)	5,572
Cash flows from investing activities:
Purchases of available-for-sale debt securities	(161,775)	(78,897)
Proceeds from maturities of available-for-sale debt securities	99,878	5,700
Purchases of property and equipment	(3,246)	(8,382)	(7,852)
Net cash used in investing activities	(65,143)	(81,579)	(7,852)
Cash flows from financing activities:
Proceeds from public offerings, net of underwriting discounts and commissions	117,500	144,025
Payments of costs related to public offerings	(435)	(4,197)
Proceeds from exercise or settlement of equity awards	4,203	1,396	76
Proceeds from borrowings		20,000
Payments of borrowing costs		(490)
Repayments under borrowing arrangements		(25,000)	(645)
Debt extinguishment costs		(794)
Other		8	(22)
Net cash provided by (used in) financing activities	121,268	134,948	(591)
Effect of exchange rates on cash flows and cash equivalents	7	2	(2)
Net change in cash and cash equivalents	13,479	35,302	(2,873)
Cash and cash equivalents, beginning of period	55,046	19,744	22,617
Cash and cash equivalents, end of period	68,525	55,046	19,744
Supplemental disclosures of cash flow information:
Cash paid for interest		1,257	698
Income taxes paid	35	6	7
Supplemental disclosures of noncash investing and financing activities:
Acquisition of property and equipment included in accounts payable and accrued liabilities	$ 282	$ 41	323
Convertible Notes conversion on September 20, 2018 (see Note 6)			$ 13,431

Company and Nature of Business

Company and Nature of Business	12 Months Ended
	Dec. 31, 2020
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Company and Nature of Business	Note 1. Company and Nature of Business Personalis, Inc. (the “Company”) was incorporated in Delaware on February 21, 2011 and began operations in September 2011. The Company formed a wholly owned subsidiary, Personalis (UK) Ltd., in August 2013 and a wholly owned subsidiary, Shanghai Personalis Biotechnology Co., Ltd. (which is referred to as “Personalis (Shanghai) Ltd” herein), in October 2020. The Company is a growing cancer genomics company transforming the development of next-generation therapies by providing more comprehensive molecular data about each patient’s cancer and immune response. The Company provides sequencing and data analysis services to support the development of cancer therapies. The Company also provides sequencing and data analysis services to support population sequencing initiatives, which accounts for the majority of revenues. Cancer genomic services are sold primarily to pharmaceutical companies, biopharmaceutical companies, universities, non-profits, and government entities, while services for population sequencing initiatives are sold primarily to government entities. The principal markets for the Company’s services are the United States and Europe. In June 2020, the Company began partnering with a clinical genomics and life sciences company headquartered in China as a means to expand business operations into China. The Company has incurred losses to date and expects to incur additional losses for the foreseeable future. The Company continues to invest the majority of its resources in the development and growth of its business, including investments in product development and sales and marketing efforts. The Company’s activities have been financed to date primarily through the sale of equity securities and cash from operations .

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 The consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”) and the applicable rules and regulations of the Securities and Exchange Commission (“SEC”) regarding annual reporting. The consolidated financial statements include the accounts of Personalis, Inc. and its wholly owned subsidiaries, Personalis (UK) Ltd. and Personalis (Shanghai) Ltd. All intercompany balances and transactions have been eliminated in consolidation. The Company began presenting “Long-term operating lease liabilities” and “Operating lease liabilities” separately in the consolidated balance sheets and consolidated statements of cash flows, respectively, in 2020. Amounts reported in previous periods were reclassified to conform to the current presentation. Use of Estimates The preparation of consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, and disclosure of contingent assets and liabilities, at the date of the consolidated financial statements and the reported amounts of revenues and expenses during the reporting period. The estimates include, but are not limited to, useful lives assigned to long-lived assets, the valuation of common and convertible redeemable preferred stock and related warrants and options, the valuation of the compound derivative instrument, the valuation of stock-based awards, and provisions for income taxes and contingencies. Actual results could differ from these estimates, and such differences could be material to the Company’s consolidated financial position and results of operations. Reverse Stock Split On June 4, 2019, the Company filed an amendment to the Company’s amended and restated certificate of incorporation to effect a reverse split of shares of the Company’s common stock and redeemable convertible preferred stock on a four-for-one basis (the “Reverse Stock Split”). The par value of the common stock and redeemable convertible preferred stock was not adjusted as a result of the Reverse Stock Split. All references to common stock, options to purchase common stock, share data, per share data, redeemable convertible preferred stock and related information contained in these consolidated financial statements have been retrospectively adjusted to reflect the effect of the Reverse Stock Split for all periods presented. Initial Public Offering On June 24, 2019, the Company completed an initial public offering (“IPO”) in which it issued and sold 9,109,725 shares of its common stock at a public offering price of $17.00 per share. The Company received net proceeds of $139.8 million after deducting underwriting discounts, commissions and offering expenses. Offering expenses were $4.2 million and consisted of fees and expenses incurred in connection with the sale of the Company’s common stock in the IPO, including legal, accounting, printing, and other IPO-related costs. A warrant to purchase 188,643 shares of our common stock was exercised prior to completion of the IPO. In addition, in connection with the IPO, all shares of the Company’s then-outstanding redeemable convertible preferred stock were automatically converted into 18,474,703 shares of the Company’s common stock, and all then-outstanding warrants to purchase the Company’s convertible preferred stock were automatically converted into warrants to purchase 84,585 shares of the Company’s common stock, all of which were exercised as of December 31, 2020 (see Note 10). Follow-On Offering On August 14, 2020, the Company completed a follow-on offering in which it issued and sold 6,578,947 shares of its common stock at a public offering price of $19.00 per share. The Company received net proceeds of $117.1 million after deducting underwriting discounts, commissions, and offering expenses. Offering expenses were $0.4 million consisting of legal, accounting, printing and other offering-related costs. Concentration of Credit Risk and Other Risks and Uncertainties The Company is subject to credit risk from its portfolio of cash and cash equivalents. The Company’s cash and cash equivalents are deposited with high-quality financial institutions. Deposits at these institutions may, at times, exceed federally insured limits. Management believes these financial institutions are financially sound and, accordingly, that minimal credit risk exists. The Company has not experienced any losses on its deposits of cash and cash equivalents. The Company also invests in investment ‑ ‑ The Company purchases various reagents and sequencing materials from sole source suppliers. Any extended interruption in the supply of these materials could result in the Company’s inability to secure sufficient materials to conduct business and meet customer demand. The Company routinely assesses the creditworthiness of its customers and does not require collateral. The Company has not experienced any material losses related to receivables from individual customers, or groups of customers. The Company maintains an allowance for doubtful accounts, which was $0.1 million as of December 31, 2020 and 2019. During the year ended December 31, 2019, bad debt expense was $0.1 million and included in selling, general and administrative expenses. The Company had no bad debt expense in 2020 and 2018. Significant customers are those that represent more than 10% of the Company’s total revenues or accounts receivable balance at each respective balance sheet date. For each significant customer, revenue as a percentage of total revenues and accounts receivable as a percentage of total accounts receivable are as follows: Revenues Accounts Receivable Year Ended December 31, December 31, 2020 2019 2018 2020 2019 VA MVP 71% 67% 49% * 19% Pfizer Inc. * 13% 10% * 23% Merck & Co., Inc. * * 12% 59% * Indivumed GmbH * * * * 30% * Less than 10% of revenues or accounts receivable Revenue Recognition The Company applies the revenue recognition guidance in accordance with Financial Accounting Standards Board (“FASB”) Accounting Standards Codification (“ASC”) Topic 606, Revenue from Contracts with Customers (“Topic 606”). Revenue Recognition The revenue guidance provides a five-step framework through which revenue is recognized when control of promised goods or services is transferred to a customer at an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. To determine revenue recognition for arrangements that the Company concludes are within the scope of Topic 606, management performs the following five steps: (i) identifies the contract(s) with a customer; (ii) identifies the performance obligations in the contract(s); (iii) determines the transaction price, including whether there are any constraints on variable consideration; (iv) allocates the transaction price to the performance obligations; and (v) recognizes revenue when (or as) the Company satisfies a performance obligation. At contract inception, once a contract is determined to be within the scope of the new revenue standard, the Company assesses whether individual goods or services promised within each contract are distinct and, therefore, represent separate performance obligations. The Company derives revenues from sequencing and data analysis services to support the development of personalized cancer vaccines and other next-generation cancer immunotherapies, as well as to support population sequencing initiatives. The Company’s contracts are in the form of a combination of signed agreements, statements of work, and/or purchase orders. Under Topic 606, the Company accounts for a contract with a customer when there is approval and commitment from both parties, the rights of the parties are identified, payment terms are identified, the contract has commercial substance, and it is probable that the Company will collect substantially all of the consideration to which it will be entitled. The sequencing and data analysis services are the only distinct services that meet the definition of a performance obligation and are accounted for as one performance obligation under Topic 606. The Company recognizes revenue from such services at the point in time when control of the test results is transferred to the customer. The Company has elected to exclude all sales and value added taxes from the measurement of the transaction price. Sequencing and data analysis services are based on a fixed price per test. Payment terms and conditions vary by contract and customer. The Company’s standard payment terms are less than 90 days from the invoice date. In instances where the timing of the Company’s revenue recognition differs from the timing of its invoicing, the Company does not assess whether a contract has a significant financing component if the expectation at contract inception is such that the period between payment by the customer and the transfer of the promised services to the customer will be one year or less. After assessing each of its revenue-generating arrangements to determine whether a significant financing component exists, the Company concluded that a significant financing component does not exist in any of its arrangements. The primary purpose of the Company’s invoicing terms is to provide customers with simplified and predictable ways of purchasing the Company’s services and to provide payment protection for the Company. Practical Expedients and Exemptions As a practical expedient, the Company recognizes the incremental costs of obtaining contracts, such as sales commissions, as an expense when incurred since the amortization period of the asset the Company otherwise would have recognized is one year or less. Sales commissions are recorded within selling, general, and administrative expenses in the consolidated statements of operations. Costs of Revenues Costs of revenues consist of raw materials costs, personnel costs (salaries, bonuses, benefits, payroll taxes, and stock-based compensation), laboratory supplies and consumables, depreciation and maintenance on equipment, and allocated facilities and information technology costs. Research and Development Expenses The Company charges research and development costs to expenses as incurred, including lab and automation development costs. The expenses primarily consist of personnel costs (salaries, bonuses, stock-based compensation, payroll taxes, and benefits), laboratory supplies and consumables, costs of purchasing samples for research purposes, depreciation and maintenance on equipment, and allocated facilities and information technology costs. Stock-Based Compensation For options granted to employees, non-employees, and directors, stock-based compensation is measured at grant date based on the fair value of the award. The Company determines the grant-date fair value of the options using the Black-Scholes option-pricing model, except for certain performance-based awards for which an alternative valuation method may be used. The Company determines the fair value of restricted stock unit awards using the closing market price of the Company’s common stock on the date of grant. The grant-date fair value of awards is amortized over the employees’ requisite service period on a straight-line basis, or the non-employees’ vesting period as the goods are received or services rendered. Forfeitures are accounted for as they occur. Additionally, the Company’s 2019 Employee Stock Purchase Plan is deemed to be a compensatory plan and therefore is included in stock-based compensation expense. Inputs used in Black-Scholes option-pricing models to measure fair value of options are summarized as follows: Expected Term. The expected term is calculated using the simplified method, which is available if there is insufficient historical data about exercise patterns and post-vesting employment termination behavior. The simplified method is based on the vesting period and the contractual term for each grant, or for each vesting tranche for awards with graded vesting. The midpoint of the vesting date and the maximum contractual expiration date is used as the expected term under this method. For awards with multiple vesting tranches, the times from grant until the midpoints for each of the tranches may be averaged to provide an overall expected term. Expected Volatility. The Company used an average historical stock price volatility of a peer group of publicly traded companies to be representative of its expected future stock price volatility, as the Company did not have sufficient trading history for its common stock. For purposes of identifying these peer companies, the Company considered the industry, stage of development, size, and financial leverage of potential comparable companies. For each grant, the Company measured historical volatility over a period equivalent to the expected term. Risk-Free Interest Rate. The risk-free interest rate is based on the implied yield currently available on U.S. Treasury zero-coupon issues with remaining terms equivalent to the expected term of a stock award. Expected Dividend Rate. The Company has not paid and does not anticipate paying any dividends in the near future. Accordingly, the Company has estimated the dividend yield to be zero. Foreign Currency Translation The Company considers the functional currencies of its foreign subsidiaries to be the local currency. Assets and liabilities recorded in foreign currencies are translated at the exchange rate as of the balance sheet date, and costs and expenses are translated at average exchange rates in effect during the period. Equity transactions are translated using historical exchange rates. The effects of foreign currency translation adjustments are recorded as a separate component of accumulated other comprehensive income (loss) in the consolidated balance sheets. Comprehensive Loss Comprehensive loss includes all changes in equity (net assets) during the period from nonowner sources. The Company’s comprehensive loss consists of its net loss, its cumulative translation adjustments, and its unrealized gains or losses on available-for-sale debt securities. Income Taxes The Company uses the asset and liability method under ASC Topic 740, Income Taxes, in accounting for income taxes. Deferred tax assets and liabilities are recognized for the estimated future tax consequences attributable to differences between the consolidated financial statement carrying amounts of existing assets and liabilities and their respective tax bases. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. Deferred tax expenses or benefits are the result of changes in the deferred tax assets and liabilities. Valuation allowances are established when necessary to reduce deferred tax assets where it is more likely than not that the deferred tax assets will not be realized. ASC Topic 740 clarifies the accounting for uncertainty in income taxes recognized in the financial statements. ASC Topic 740 provides that a tax benefit from an uncertain tax position may be recognized when it is more likely than not that the position will be sustained upon audit, including resolutions of any related appeals or litigation processes, based on the technical merits of the position. ASC Topic 740 also provides guidance on measurement, derecognition, classification, interest and penalties, accounting in interim periods, disclosure, and transition. The Company recognizes interest and penalties related to unrecognized tax benefits within the income tax expense line in the accompanying consolidated statements of operations. Accrued interest and penalties are included within the related liability line in the consolidated balance sheets. Net Loss per Share Attributable to Common Stockholders Basic net loss per common share is calculated by dividing the net loss attributable to common stockholders by the weighted-average number of shares of common stock outstanding during the period, without consideration of potentially dilutive securities. Diluted net loss per share is computed by dividing the net loss attributable to common stockholders by the weighted-average number of shares of common stock and potentially dilutive securities outstanding for the period. For purposes of the diluted net loss per share calculation, the redeemable convertible preferred stock, convertible preferred stock warrants, common stock warrants, common stock subject to repurchase, and equity awards are considered to be potentially dilutive securities. Basic and diluted net loss attributable to common stockholders per share is presented in conformity with the two-class method required for participating securities as the redeemable convertible preferred stock is considered a participating security. The Company’s participating securities do not have a contractual obligation to share in the Company’s losses. As such, the net loss is attributed entirely to common stockholders. Because the Company has reported a net loss for the reporting periods presented, the diluted net loss per common share is the same as basic net loss per common share for those periods. Cash and Cash Equivalents Cash equivalents consist of highly liquid investments with maturities at the time of purchase of three months or less. Cash equivalents include bank demand deposits and money market accounts that invest primarily in cash, U.S. Treasury bills, notes, and other obligations issued or guaranteed as to principal and interest by the U.S. Government, its agencies or instrumentalities, and repurchase agreements secured by such obligations or cash. Cash equivalents also include commercial paper, which are marketable debt securities recorded at fair value and accounted for in the same manner as other marketable debt securities described below. Short-term Investments The Company’s investments in marketable debt securities are classified as available-for-sale and recorded at fair value. Investments with original maturities of greater than three months and remaining maturities of less than one year are classified as short-term investments. Investments with maturities beyond one year may be classified as short-term based on their highly liquid nature and because such marketable securities represent the investment of cash that is available for current operations. Short-term investments primarily consist of U.S. agency bonds, commercial paper, corporate bonds, asset-backed securities, and U.S. treasuries. Unrealized gains and losses are included in accumulated other comprehensive income (loss) in stockholders’ equity. Any discount or premium arising at purchase is accreted or amortized to interest income or expense. Realized gains and losses and declines in fair value, if any, judged to be other than temporary are reported in other income (expense), net. When securities are sold, any associated unrealized gain or loss initially recorded as a separate component of stockholders’ equity is reclassified out of stockholders’ equity on a specific-identification basis and recorded in earnings for the period. The Company periodically evaluates whether declines in fair values of its investments below their book values are other-than-temporary. This evaluation consists of several qualitative and quantitative factors regarding the severity and duration of the unrealized loss as well as the Company’s ability and intent to hold the marketable security until a forecasted recovery occurs. Factors considered include quoted market prices, recent financial results and operating trends, implied values from any recent transactions or offers of investee securities, credit quality of debt instrument issuers, other publicly available information that may affect the value of the marketable security, duration and severity of the decline in value, and management’s strategy and intentions for holding the marketable security. To date, the Company has not recorded any impairment charges on its marketable securities related to other-than-temporary declines in market value. Fair Value Measurements Financial assets and liabilities are recorded at fair value. Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability (an exit price) in an orderly transaction between market participants at the reporting date. The hierarchy below lists three levels of fair value based on the extent to which inputs used in measuring fair value are observable in the market. Observable inputs reflect market data obtained from independent sources while unobservable inputs reflect market assumptions made by the reporting entity. The three-level hierarchy for the inputs to valuation techniques used to measure fair value is briefly summarized as follows: Level 1 — Unadjusted quoted prices in active markets that are accessible to the reporting entity at the measurement date for identical assets and liabilities. Level 2 — Inputs other than quoted prices in active markets for identical assets and liabilities that are observable either directly or indirectly for substantially the full term of the asset or liability. Level 2 inputs include the following: • Quoted prices for similar assets and liabilities in active markets. • Quoted prices for identical or similar assets or liabilities in markets that are not active. • Observable inputs other than quoted prices that are used in the valuation of the assets or liabilities (e.g., interest rate and yield curve quotes at commonly quoted intervals). • Inputs that are derived principally from or are corroborated by observable market data by correlation or other means. Level 3 — Unobservable inputs for the assets or liabilities (i.e., supported by little or no market activity). Level 3 inputs include management’s own assumptions about the assumptions that market participants would use in pricing the asset or liability (including assumptions about risk). This hierarchy requires the Company to use observable market data, when available, and to minimize the use of unobservable inputs when determining fair value. Accounts Receivable, Net Trade accounts receivable are recorded at the invoiced amount and are noninterest bearing. At each reporting period, management reviews all outstanding customer balances to determine if the facts and circumstances of each customer relationship indicate the need for a reserve. A reserve is recorded when it is probable that a loss has been incurred based on past events and conditions existing at the date of the financial statements, and the loss is reasonably estimated. Inventory and Other Deferred Costs Inventory, consisting of supplies used in the Company’s genomic analysis contracts, are valued at the lower of cost or net realizable value. Cost is determined using actual costs, on a first-in, first-out basis. Other deferred costs relate to work in process for costs incurred on genomic analysis contracts that have not been completed or recognized as revenues. Other deferred costs represent materials used in sequencing services, labor, and overhead allocations. Property and Equipment, Net Property and equipment are recorded at cost, less accumulated depreciation and amortization, and are depreciated on a straight-line basis over the estimated useful lives of the related assets, which is generally three to five years for computer equipment, two years for software, three years for furniture and equipment, and five years for machinery and equipment. Leasehold improvements are amortized over the shorter of the lease term or the estimated useful life of the related asset. Upon retirement or sale, the cost and related accumulated depreciation and amortization are removed from the consolidated balance sheet, and the resulting gain or loss is reflected in the consolidated statements of operations. Maintenance and repairs that are not considered improvements and do not extend the useful lives of the assets are charged to expense as incurred. Construction-in-process assets consist primarily of computer equipment and machinery and equipment that have not yet been placed in service. These assets are stated at cost and are not depreciated. Once the assets are placed into service, assets are reclassified to the appropriate asset class based on their nature and depreciated in accordance with the useful lives above. Leases The Company categorizes leases with contractual terms longer than twelve months as either operating or finance leases. Finance leases are generally those leases that allow the Company to substantially utilize or pay for the entire asset over its estimated life. All other leases are categorized as operating leases. As of December 31, 2020, the Company had no finance leases. Certain lease contracts include obligations to pay for other services, such as maintenance. The Company elected to account for these other services as a component of the lease (i.e., the Company elected the practical expedient not to separate lease and non-lease components). Lease liabilities are recognized at the present value of the fixed lease payments, reduced by landlord incentives, using a discount rate based on the Company’s current borrowing rate at the lease commencement date, adjusted for various factors including level of collateralization and term (the “incremental borrowing rate”), unless the rate implicit in the lease is readily determinable. The current portion of lease liabilities is included in “Accrued and other current liabilities.” Lease assets are recognized based on the initial present value of the fixed lease payments, reduced by landlord incentives, plus any direct costs from executing the leases or lease prepayments reclassified from “Other long-term assets” upon lease commencement. Lease assets are presented as “Operating lease right-of-use assets” as a long-term asset. Leasehold improvements are capitalized at cost and amortized over the lesser of their expected useful life or the lease term. Costs associated with operating lease assets are recognized on a straight-line basis within operating expenses over the term of the lease. The Company has made an accounting policy election not to recognize right-of-use assets and lease liabilities that arise from leases with a term of 12 months or less. Lease payments are recognized as an expense on a straight-line basis over the lease term. Recent Accounting Pronouncements New Accounting Pronouncements Not Yet Adopted In June 2016, the FASB issued Accounting Standards Update (“ASU”) No. 2016-13, Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments, which amends the impairment model by requiring entities to use a forward-looking approach based on expected losses to estimate credit losses on certain types of financial instruments, including trade receivables. The accounting update also made minor changes to the impairment model for available-for-sale debt securities. In November of 2019, the FASB delayed the effective date for Smaller Reporting Companies to the first quarter of 2023. The Company is currently evaluating the impact of the new guidance on its consolidated financial statements and related disclosures. The Company will apply the new guidance by means of a cumulative-effect adjustment to the opening retained earnings as of the beginning of the first reporting period in which the guidance is effective. JOBS Act Accounting Election The Company is an emerging growth company, as defined in the Jumpstart Our Business Startups Act (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 irrevocably elected not to avail itself of this exemption from new or revised accounting standards, and therefore, the Company will be subject to the same new or revised accounting standards as other public companies that are not emerging growth companies.

Revenues

Revenues	12 Months Ended
	Dec. 31, 2020
Revenue From Contract With Customer [Abstract]
Revenues	Note 3. Revenues The following table presents the Company’s revenues disaggregated by customer type (in thousands): Year Ended December 31, 2020 2019 2018 VA MVP $ 56,154 $ 43,545 $ 18,601 All other customers 22,494 21,662 19,173 Total $ 78,648 $ 65,207 $ 37,774 Revenues from countries outside of the United States, based on the billing addresses of customers, represented 5%, 4%, and 3% of the Company’s revenues for the years ended December 31, 2020, 2019 and 2018, respectively. Contract Assets and Liabilities Contract assets as of December 31, 2020 were immaterial. The Company had no contract assets as of December 31, 2019. The Company’s contract liabilities consist of customer deposits in excess of revenues recognized and are presented as current liabilities in the consolidated balance sheets. The balance of contract liabilities was $21.0 million and $36.0 million as of December 31, 2020 and 2019, respectively. Revenues recognized in 2020, 2019, and 2018 that were included in the contract liability balance at the beginning of each reporting period were $33.8 Revenues allocated to remaining performance obligations represent contracted revenues that have not yet been recognized (“contracted not recognized revenues”), which include VA MVP contract liabilities and amounts that will be invoiced and recognized as revenues in future periods. Contracted not recognized revenues were $43.5 million as of December 31, 2020, which the Company expects to recognize as revenues within approximately three quarters. The Company has elected the optional exemption that allows for the exclusion of contracts with an original expected duration of one year or less.

Balance Sheet Details

Balance Sheet Details	12 Months Ended
	Dec. 31, 2020
Balance Sheet Related Disclosures [Abstract]
Balance Sheet Details	Note 4. Balance Sheet Details Inventory and other deferred costs consist of the following (in thousands): December 31, 2020 2019 Raw materials $ 2,675 $ 1,424 Other deferred costs 2,964 3,182 Total inventory and other deferred costs $ 5,639 $ 4,606 Property and equipment, net consists of the following (in thousands): December 31, 2020 2019 Machinery and equipment $ 13,854 $ 12,511 Computer equipment 10,467 8,855 Furniture and fixtures 440 368 Leasehold improvement 987 987 Computer software costs 278 198 Construction in progress 322 234 Total 26,348 23,153 Less: Accumulated depreciation and amortization (14,514 ) (9,047 ) Property and equipment, net $ 11,834 $ 14,106 Depreciation and amortization expense for the years ended December 31, 2020, 2019, and 2018 was $5.8 million, $4.7 million, and $3.1 million, respectively. Accrued and other current liabilities consist of the following (in thousands): December 31, 2020 2019 Accrued compensation $ 8,041 $ 4,147 Operating lease liabilities 2,445 1,361 Accrued liabilities 313 689 Accrued taxes 95 210 Other current liabilities 407 241 Total accrued and other current liabilities $ 11,301 $ 6,648

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2020
Fair Value Disclosures [Abstract]
Fair Value Measurements	Note 5. Fair Value Measurements The following tables show the Company’s financial assets and liabilities measured at fair value on a recurring basis and the level of inputs used in such measurements as of December 31, 2020 and 2019 (in thousands): December 31, 2020 Adjusted Cost Unrealized Gains Unrealized Losses Fair Value Fair Value Level Assets Cash and cash equivalents: Cash $ 4,767 $ — $ — $ 4,767 Money market funds 22,614 — — 22,614 Level 1 Commercial paper 41,145 — (1 ) 41,144 Level 2 Total cash and cash equivalents 68,526 — (1 ) 68,525 Short-term investments: Commercial paper 25,470 — — 25,470 Level 2 U.S. government securities 18,260 1 — 18,261 Level 2 Corporate debt securities 29,576 — (8 ) 29,568 Level 2 U.S. agency securities 61,436 31 (1 ) 61,466 Level 2 Total short-term investments 134,742 32 (9 ) 134,765 Total assets measured at fair value $ 203,268 $ 32 $ (10 ) $ 203,290 December 31, 2019 Adjusted Cost Unrealized Gains Unrealized Losses Fair Value Fair Value Level Assets Cash and cash equivalents: Cash $ 1,271 $ — $ — $ 1,271 Money market funds 12,495 — — 12,495 Level 1 Commercial paper 41,281 — (1 ) 41,280 Level 2 Total cash and cash equivalents 55,047 — (1 ) 55,046 Short-term investments: Commercial paper 17,898 — (6 ) 17,892 Level 2 U.S. government securities 4,011 — — 4,011 Level 2 Corporate debt securities 13,953 1 (6 ) 13,948 Level 2 U.S. agency securities 32,776 20 (2 ) 32,794 Level 2 Asset-backed securities 4,598 — — 4,598 Level 2 Total short-term investments 73,236 21 (14 ) 73,243 Total assets measured at fair value $ 128,283 $ 21 $ (15 ) $ 128,289 There have been no realized gains or losses on sales of marketable securities for the periods presented. No security has been in an unrealized loss position for 12 months or greater. The Company determined that it did have the ability and intent to hold all marketable securities that have been in a continuous loss position until maturity or recovery. As of December 31, 2020, the Company does not consider any of its marketable debt securities to be other-than-temporarily impaired. The Company’s marketable debt securities at December 31, 2020 have maturities due in one year or less, except for debt securities with an aggregate cost basis and fair value of $21.1 million that have maturities ranging from 14 months to 23 months. The Black-Scholes option-pricing model was used to estimate the fair value of the convertible preferred stock warrants at the date of issuance and at each subsequent consolidated balance sheet date. The fair value of the convertible preferred stock warrants was also estimated at the time of conversion to common stock warrants (see Note 10). Under this option-pricing model, convertible preferred stock warrants were valued by creating a series of call options with exercise prices based on the liquidation preferences and conversion terms of each equity class. The values of the redeemable convertible preferred stock and common stock are inferred by analyzing these options. The fair value of each convertible preferred stock warrant was estimated using the Black-Scholes option-pricing model with the assumptions described below. Upon conversion to common stock warrants in the second quarter of 2019 (see Note 10), no further fair value measurements were made. Therefore, there is no activity with respect to periods after the second quarter of 2019. For the periods indicated, the Company has limited historical volatility information available, and the expected volatility was based on actual volatility for comparable public companies projected over the expected terms of the warrants. The Company did not apply a forfeiture rate to the warrants as there is not enough historical information available to estimate such a rate. The risk-free interest rate was based on the U.S. Treasury yield curve over the expected term of the warrants. Period Ended Year Ended June 24, 2019 December 31, 2018 Expected term (in years) 5.01 - 5.26 5.17 - 7.00 Volatility 57.20% - 57.24% 55.56% - 56.42% Risk-free interest rate 1.75% 2.58% - 3.01% Dividend yield –% –% The following table sets forth a summary of the changes in the fair value of the Company’s Level 3 financial instruments (in thousands): Warrant Liability Derivative Asset Derivative Liability Balance — December 31, 2017 $ 292 $ — $ 671 Initial fair value of derivative asset — 623 — Change in fair value 391 (97 ) (671 ) Elimination as a result of debt extinguishment — (526 ) — Balance — December 31, 2018 683 — — Change in fair value 1,403 — — Reclassification of warrant liability to additional paid-in capital on conversion (2,086 ) — — Balance — December 31, 2019 $ — $ — $ —

Borrowings

Borrowings	12 Months Ended
	Dec. 31, 2020
Debt Disclosure [Abstract]
Borrowings	Note 6. Borrowings There were no amounts outstanding under financing arrangements as of December 31, 2020 or 2019. Below are descriptions of borrowings that were outstanding for at least part of either the year ended December 31, 2019 or the year ended December 31, 2018. Term Loan In September 2014, the Company entered into a loan and security agreement with Silicon Valley Bank to borrow up to $3.0 million under an equipment loan to be secured by the equipment financed (the “Term Loan”). On October 3, 2014, the Company borrowed $2.4 million under the Term Loan. The Term Loan required 12 interest-only payments, followed by 36 equal monthly installments of principal, plus interest, which began on October 3, 2015. In connection with the Term Loan, the Company issued to the bank a warrant exercisable for ten years from the date of grant to purchase 22,489 shares of the Company’s Series B redeemable convertible preferred stock at an exercise price of $4.60 per share, which was exercised in June 2019 (see Note 10). The estimated fair value of the warrants upon draw down of $0.1 million was based on the Black-Scholes option-pricing model. The Company recorded the fair value of the warrant at issuance as a reduction in the debt-carrying value and as a warrant liability. The debt-carrying value reduction was accreted using the effective interest method as additional interest expense over the contractual period of four years for the Term Loan. Interest expense for the year ended December 31, 2018 was $0.1 million. On September 30, 2018, the Term Loan was repaid in full. Convertible Notes On June 29, 2017, the Company entered into a convertible promissory note agreement with certain existing redeemable convertible preferred stockholders and third parties (collectively, the “Investors”) for the issuance of convertible promissory notes with a face value of $12.2 million (the “Convertible Notes”). Under the terms of the Convertible Notes agreement, the Convertible Notes bore interest of 8.00% per annum, with a maturity date of June 28, 2018. In the event that the Company issued and sold shares of its equity securities (the “Equity Securities”) to Investors on or before the maturity date in an equity financing with total proceeds to the Company of not less than $10 million (including the conversion of the Convertible Notes or other convertible securities issued for capital raising purposes) (a “Qualified Financing”), then the outstanding principal amount of the Convertible Notes and any unpaid accrued interest would have automatically converted in whole without any further action by the holder into such Equity Securities sold in the Qualified Financing at a conversion price equal to the price paid per share for Equity Securities by the Investors in the Qualified Financing multiplied by 0.8. If the Company consummated a change of control while the Convertible Notes remained outstanding, the Company would have repaid the holders in cash an amount equal to 150% of the outstanding principal amount of the Convertible Notes, plus any unpaid accrued interest on the original principal. The Convertible Notes had customary events of default. Certain conversion and redemption features of the Convertible Notes met the requirements for separate accounting and were accounted for as a single, compound derivative instrument. The compound derivative instrument was recorded at fair value at inception and was subject to remeasurement to fair value at each consolidated balance sheet date, with any changes in fair value recognized in the consolidated statements of operations as other income (expense), net. The estimated fair value of the compound derivative instrument was $0.5 million at issuance and was recorded as a reduction in the carrying value of the Convertible Notes and as a single, compound derivative liability. The Convertible Notes carrying value reduction was accreted using the effective interest method as interest expense over the Convertible Notes contractual period of one year. The Convertible Notes had an effective interest rate of 12.69% per year. On May 31, 2018, the original maturity date for the Convertible Notes was extended to June 28, 2019 (previously June 28, 2018). The maturity date extension was deemed substantial and was accounted for as a debt extinguishment. In connection with the debt extinguishment on May 31, 2018, the fair value of the Convertible Notes was allocated between the carrying amount of the Convertible Notes and accrued interest of $13.1 million, a compound derivative asset of $0.6 million, and an equity component of $3.9 million, which was credited to additional paid-in capital within the consolidated statements of redeemable convertible preferred stock and stockholders’ equity (deficit). A $3.3 million loss on debt extinguishment was also recorded in the consolidated statements of operations. The new carrying value of the Convertible Notes was accreted using the effective interest method as interest expense over the new contractual period of 1.1 years. On August 20, 2018, the maturity date for the Convertible Notes was extended to September 20, 2018 (previously June 28, 2019). The term change was deemed substantial and was accounted for as a debt extinguishment. In connection with the debt extinguishment on August 20, 2018, the fair value of the Convertible Notes was allocated between the new carrying amount of the Convertible Notes and accrued interest of $13.4 million, and an equity component of $0.8 million, which resulted in a credit to additional paid-in capital. Upon modification, the compound derivative asset was eliminated. A $0.8 million loss on debt extinguishment was also recorded in the consolidated statements of operations. The new carrying value of Convertible Notes was accreted using the effective interest method as interest expense over the new contractual period of one month. On September 20, 2018, upon the maturity of the Convertible Notes, the carrying amount, including accrued interest of $13.4 million, was converted into 1,667,997 shares of the Company’s Series C redeemable convertible preferred stock at a conversion price equal to $8.052 per share. No gain or loss was recorded on the conversion. The Convertible Notes interest expense for the year ended December 31, 2018 was $0.9 million. Revolving Loan In June 2017, the Company entered into a $10.0 million revolving loan and security agreement (the “Revolving Loan”) with TriplePoint Capital LLC (“TriplePoint”). The Company borrowed $5.0 million under the Revolving Loan. Borrowings under the Revolving Loan bear an interest rate of prime, plus 6.75%. The Revolving Loan also has a 5.5% end of term loan payment on the highest outstanding principal amount. The Revolving Loan requires monthly interest-only payments until the maturity date. The Revolving Loan’s original maturity date was December 31, 2018, and in December 2018 the maturity date was further extended until March 22, 2019. Upon determining that the change in cash flows between the previous and revised credit facility was not greater than 10%, the Company accounted for the transaction as a debt modification. In connection with the Revolving Loan, the Company issued to TriplePoint a warrant to purchase up to 62,096 shares of the Company’s Series C redeemable convertible preferred stock at an exercise price of $8.052 per share, which was exercised in August 2020 (see Note 10). The estimated fair value of the warrant upon draw down of $0.1 million was based on the Black-Scholes option-pricing model. The Company recorded the fair value of the warrant at issuance as a reduction in the debt-carrying value and as a warrant liability. The debt-carrying value reduction was accreted using the effective interest method as additional interest expense over the contractual period of 1.5 years for the Revolving Loan. The Revolving Loan had an effective interest rate of 19.22% per year. Interest expense was $0.2 million and $0.9 million for the years ended December 31, 2019 and 2018, respectively. On March 22, 2019, this Revolving Loan was repaid in full. Growth Capital Loan On March 22, 2019, the Company entered into a growth capital loan (the “Growth Capital Loan”) with TriplePoint to provide for a $20.0 million growth capital loan facility and had drawn down the full $20.0 million available under the facility. The Company used $5.1 million of the Growth Capital Loan to repay, in its entirety, all amounts outstanding under the Revolving Loan. Borrowings under the Growth Capital Loan bore interest at a floating rate of prime, plus 5.00% for borrowings up to $15.0 million and the prime rate plus 6.50% for borrowings greater than $15.0 million. Under the agreement, the Company was required to make monthly interest-only payments through April 1, 2020 and was required to make 36 equal monthly payments of principal, plus accrued interest, from April 1, 2020 through March 1, 2023, when all unpaid principal and interest was to become due and payable. The agreement allowed voluntary prepayment of all, but not part, of the outstanding principal at any time prior to the maturity date, subject to a prepayment fee of 1.00% of the outstanding balance if prepaid in months one through 12 of the loan term. In addition to the final payment, the Company paid an amount equal to 2.75% of each principal amount drawn under this Growth Capital Loan facility. In connection with the Growth Capital Loan, the Company issued a warrant to purchase 65,502 shares of common stock to TriplePoint at an exercise price of $9.16 per share, which was exercised in August 2020 (see Note 11). The Company recorded the issuance-date fair value of the warrant of $0.6 million and fees paid to TriplePoint of $0.3 million as a debt discount, which was amortized over the term of the Growth Capital Loan using the effective interest rate method. Upon issuance, the Growth Capital Loan had an effective interest rate of 15.23% per year. Interest expense for the year ended December 31, 2019 was $1.0 million. On August 14, 2019, the Company paid off the Growth Capital Loan in its entirety. In connection with this debt repayment, the Company recorded a $1.7 million loss on extinguishment of debt in the consolidated statements of operations.

Leases

Leases	12 Months Ended
	Dec. 31, 2020
Leases [Abstract]
Leases	Note 7. Leases In February 2015, the Company entered into a noncancelable operating lease for approximately 31,280 square feet of space used for its current laboratory and corporate headquarters. In April 2020, the Company extended the lease term. The lease expires on November 30, 2027 and includes an option to extend the term for a period of three years with rent payments equal to then current fair market rental for the space. The Company determined the extension option is not reasonably certain to be exercised. The lease contains a leasehold improvement incentive and escalating rent payments. In August 2019, the Company entered into a noncancelable operating lease for a co-located data center space. The lease expires on August 31, 2022 and includes an option to extend the term for a period of three years immediately following the expiration of the term with rent payments to be negotiated upon such a renewal. The Company determined the extension is not reasonably certain to be exercised. In April 2020, the lease was modified to increase the data center space available for the Company’s use for the remainder of the lease term. Operating lease cost for the years ended December 31, 2020 and 2019 was $2.3 million and $1.1 million, respectively. As of December 31, 2020, the Company’s operating leases had a weighted-average remaining lease term of 6.4 years and a weighted-average discount rate of 10.7%. The Company’s discount rates are based on estimates of its incremental borrowing rate, as the discount rates implicit in the Company’s lease cannot be readily determined. Future lease payments under operating leases as of December 31, 2020 were as follows (in thousands): Amount 2021 $ 2,558 2022 2,194 2023 2,047 2024 2,113 2025 2,182 2026 and thereafter 4,378 Total future minimum lease payments 15,472 Less: imputed interest (4,486 ) Present value of future minimum lease payments 10,986 Less: current portion of operating lease liability (2,445 ) Long-term operating lease liabilities $ 8,541 Cash paid for operating lease liabilities, included in cash flow from operating activities in the Consolidated Statement of Cash Flows, for the years ended December 31, 2020 and 2019, was $1.7 million and $1.2 million, respectively. Right-of-use assets obtained in exchange for new operating lease liabilities, during 2020 and 2019, were $9.8 million and $2.8 million, respectively, including the impact of adopting ASU 2016-02, Leases (Topic 842) in the first quarter of 2019.

Redeemable Convertible Preferre

Redeemable Convertible Preferred Stock	12 Months Ended
	Dec. 31, 2020
Temporary Equity Disclosure [Abstract]
Redeemable Convertible Preferred Stock	Note 8. Redeemable Convertible Preferred Stock Series A redeemable convertible preferred stock, Series B redeemable convertible preferred stock, and Series C redeemable convertible preferred stock (collectively the “Redeemable Convertible Preferred Stock”) outstanding consisted of the following as of December 31, 2018 and as of immediately prior to the automatic conversion of the Redeemable Convertible Preferred Stock into common stock: December 31, 2018 Shares Authorized Shares Issued and Outstanding Aggregate Liquidation Preference Net Carrying Value (in thousands) Series A 31,250,000 7,812,497 $ 20,500 $ 20,261 Series B 19,288,150 4,799,548 22,078 22,047 Series C 24,700,000 5,862,697 47,206 47,096 Total redeemable convertible preferred stock 75,238,150 18,474,742 $ 89,784 $ 89,404 Immediately prior to the closing of the Company’s IPO, all shares of the Company’s then-outstanding Redeemable Convertible Preferred Stock, as shown in the table above, automatically converted on a one-for-one basis into an aggregate of 18,474,703 shares of common stock. The Reverse Stock Split was effected on a holder-by-holder basis with no fractional shares issued, which resulted in 39 fewer shares of common stock issued as compared to the amounts shown in the above table.

Stock-Based Compensation

Stock-Based Compensation	12 Months Ended
	Dec. 31, 2020
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock-Based Compensation	Note 9. Stock-Based Compensation 2011 Equity Incentive Plan In 2011, the Company established its 2011 Equity Incentive Plan (the “2011 Plan”) that provided for the granting of stock options to employees and nonemployees of the Company. Under the 2011 Plan, the Company had the ability to issue incentive stock options (“ISOs”), nonstatutory stock options (“NSOs”), stock appreciation rights, restricted stock awards, and restricted stock unit awards (“RSUs”). Options under the 2011 Plan could be granted for periods of up to 10 years. The ISOs could be granted at a price per share not less than the fair value at the date of grant. For stock option grants issued prior to December 31, 2015, the Company allowed employees to exercise options granted under the 2011 Plan prior to vesting (early exercise of stock options). The unvested shares were subject to the Company’s repurchase rights at the original purchase price. Initially, the proceeds were recorded as an accrued liability from the early exercise of stock options and reclassified to common stock as the Company’s repurchase rights lapsed. There were no unvested shares subject to the Company’s repurchase rights as of December 31, 2020 and 2019. 2019 Equity Incentive Plan The Company’s board of directors adopted and the Company’s stockholders approved the 2019 Equity Incentive Plan (the “2019 Plan”) in May 2019 and June 2019, respectively. The 2019 Plan became effective in June 2019 in connection with the Company’s IPO, and no further grants will be made under the 2011 Plan. Shares reserved and remaining available for issuance under the 2011 Plan were added to the 2019 Plan reserve upon its effectiveness . The 2019 Plan provides for the grant of ISOs, NSOs, stock appreciation rights, restricted stock awards, RSUs, performance-based stock awards, and other forms of equity compensation. Additionally, the 2019 Plan provides for the grant of performance cash awards. ISOs may be granted only to the Company’s employees and to any of the Company’s parent or subsidiary corporation’s employees. All other awards may be granted to employees, including officers, and to non-employee directors and consultants of the Company and any of the Company’s affiliates. The exercise price of a stock option generally cannot be less than 100% of the fair market value of the Company’s common stock on the date of grant. Options under the 2019 Plan may be granted for periods of up to 10 years. 2020 Inducement Plan The Compensation Committee of the Company’s board of directors adopted the 2020 Inducement Plan (the “Inducement Plan”) in May 2020, which became effective upon adoption. The Inducement Plan was adopted without stockholder approval, as permitted by the Nasdaq Stock Market rules. The Inducement Plan provides for the grant of equity-based awards, including NSOs, stock appreciation rights, restricted stock awards, RSUs, performance-based stock awards, and other forms of equity compensation, and its terms are substantially similar to the stockholder-approved 2019 Plan. In accordance with relevant Nasdaq Listing Rules, awards under the Inducement Plan may only be made to individuals not previously employees or non-employee directors of the Company (or following such individuals’ bona fide period of non-employment with the Company), as an inducement material to the individuals entry into employment with the Company. 2019 Employee Stock Purchase Plan The Company’s board of directors adopted and the Company’s stockholders approved the 2019 Employee Stock Purchase Plan (the “ESPP”) in May 2019 and June 2019, respectively. Subject to any plan limitations, the ESPP allows eligible employees to contribute, normally through payroll deductions, up to 15% of their earnings for the purchase of the Company’s common stock at a discounted price per share. The price at which common stock is purchased under the ESPP is equal to 85% of the fair market value of the Company’s common stock on the first or last day of the offering period, whichever is lower. The ESPP provides for separate six-month offering periods beginning on May 1 and November 1 of each year. Shares of common stock available for issuance under the Company’s equity incentive plans at December 31, 2020 and December 31, 2019 were as follows: December 31, 2020 2019 Reserved for issuance upon exercise of options outstanding under the 2011 Plan 3,389,711 4,474,057 Reserved for issuance upon exercise or settlement of awards outstanding under the 2019 Plan 2,399,513 377,378 Reserved and available for issuance under the 2019 Plan 1,977,069 2,392,343 Reserved for issuance upon exercise or settlement of awards outstanding under the Inducement Plan 199,300 — Reserved and available for issuance under the Inducement Plan 800,700 — Reserved and available for issuance under the ESPP 320,582 172,316 Total number of shares reserved 9,086,875 7,416,094 Stock Option Activity A summary of the Company’s stock option activity (excluding performance-based stock option activity summarized further below) under the 2011 Plan, 2019 Plan, and Inducement Plan for the years ended December 31, 2020, 2019 and 2018 is as follows: Outstanding Options (in thousands, except share and per share data) Number of Shares Weighted- Average Exercise Price Weighted- Average Remaining Contractual Term (in years) Aggregate Intrinsic Value Balance—December 31, 2017 2,884,527 $ 1.92 6.61 $ 5,860 Options granted 1,386,464 5.68 Options exercised (34,426 ) 2.80 96 Options cancelled (126,435 ) 2.96 Balance—December 31, 2018 4,110,130 $ 3.16 6.94 $ 24,716 Options granted 988,913 11.81 Options exercised (287,932 ) 2.47 Options cancelled (79,676 ) 6.61 Balance—December 31, 2019 4,731,435 $ 4.94 6.60 $ 29,730 Options granted 1,357,741 12.05 Options exercised (908,691 ) 3.07 Options cancelled (232,179 ) 7.87 Balance—December 31, 2020 4,948,306 $ 7.10 6.71 $ 146,044 Options vested and exercisable as of December 31, 2020 2,868,867 $ 4.24 5.21 $ 92,879 Options granted to new hires generally vest over a four-year period, with 25% vesting at the end of one year and the remaining vesting monthly thereafter. Options granted as merit awards generally vest monthly over a three- or four-year period. The aggregate intrinsic value of unexercised stock options is calculated as the difference between the closing price of the Company’s common stock of $36.61 on December 31, 2020 and the exercise prices of the underlying stock options. Out-of-the money stock options are excluded from the aggregate intrinsic value. The weighted-average grant date fair value of options granted was $7.17, $8.00, and $5.68 per share for the years ended December 31, 2020, 2019, and 2018, respectively. As of December 31, 2020, the unrecognized stock-based compensation of unvested options was $13.3 million, which is expected to be recognized over a weighted-average period of 2.7 years. Valuation of Stock Options The Company estimated the fair value of stock options (excluding performance-based stock options discussed below) using the Black-Scholes option-pricing model. The fair value of stock options is recognized on a straight-line basis over the requisite service periods of the awards. The fair value of stock options was estimated using the following weighted-average assumptions: Year Ended December 31, 2020 2019 2018 Expected term (in years) 5.50 - 6.40 5.00 - 6.87 1.50 - 6.35 Volatility 61.74 - 68.18% 56.20 - 63.08% 52.19 - 56.47% Risk-free interest rate 0.36 - 1.66% 1.53 - 2.52% 2.62 - 2.88% Dividend yield –% –% –% Performance-Based Stock Option Activity Pursuant to the 2019 Plan, in March 2020, the Company’s board of directors granted the Company’s Chief Executive Officer a performance-based stock option (“PSO”) to purchase 421,000 shares of common stock. The PSO was subject to the Chief Executive Officer’s continued service to the Company through the date of vesting and, if the performance condition were not met within 10 years from the date of grant, the PSO would be canceled. The shares subject to the PSO would vest in full if the Company’s average market capitalization is equal to or greater than $1 billion over a 30 calendar day period. Upon a change in control, the vesting of the shares subject to the PSO would accelerate on a pro rata basis based on the price per share in such change in control transaction multiplied by the price per share at such time divided by $1 billion, with up to 100% of the shares eligible for such accelerated vesting. A summary of the Company’s performance-based stock option activity under the 2019 Plan for the year ended December 31, 2020 is as follows: Outstanding Performance-Based Options (in thousands, except share and per share data) Number of Shares Weighted- Average Exercise Price Weighted- Average Remaining Contractual Term (in years) Aggregate Intrinsic Value Balance—December 31, 2019 — $ — — $ — Options granted 421,000 5.10 Options exercised — Options cancelled — Balance—December 31, 2020 421,000 $ 5.10 9.21 $ 13,266 Options vested and exercisable as of December 31, 2020 421,000 $ 5.10 9.21 $ 13,266 The aggregate intrinsic value of unexercised stock options is calculated as the difference between the closing price of the Company’s common stock of $36.61 on December 31, 2020 and the exercise price of the underlying stock options. During the last quarter of 2020, the Company’s average market capitalization was equal to or greater than $1 billion over a 30 calendar day period and the PSO vested in full. As of December 31, 2020, there is no remaining unrecognized stock-based compensation cost. Valuation of Performance-Based Stock Options The Company estimated the fair value of the PSO using a Monte Carlo Model and the following assumptions and estimates: 2020 Performance period (in years) 10.00 Derived service period (in years) 4.55 Volatility 63.60 % Risk-free interest rate 1.02 % Dividend yield –% Estimated fair value (per share) $ 3.31 Restricted Stock Units Activity A summary of the Company’s RSU activity under the 2019 Plan and Inducement Plan for the years ended December 31, 2020 and 2019 is as follows: Unvested Restricted Stock Units (in thousands, except share and per share data) Number of Shares Weighted- Average Grant Date Fair Value Aggregate Fair Value Balance—December 31, 2018 — $ — RSUs granted 120,000 8.86 RSUs vested — — RSUs cancelled — — Balance—December 31, 2019 120,000 $ 8.86 $ 1,308 RSUs granted 648,000 9.93 RSUs vested (130,945 ) 7.09 2,991 RSUs cancelled (17,837 ) 6.83 Balance—December 31, 2020 619,218 $ 10.41 $ 22,670 The Company granted RSUs to employees to receive shares of the Company’s common stock. The RSUs awarded are subject to each individual’s continued service to the Company through each applicable vesting date. RSUs granted to new hires generally vest annually over a four-year period. RSUs granted as merit awards generally vest semi-annually over a three-year period, or in some cases quarterly over a three-year period. The Company accounted for the fair value of the RSUs using the closing market price of the Company’s common stock on the date of grant. The aggregate fair value of unvested RSUs is calculated using the closing price of the Company’s common stock of $36.61 on December 31, 2020. As of December 31, 2020, the unrecognized stock-based compensation cost of unvested RSUs was $5.9 million, which is expected to be recognized over a weighted-average period of 2.9 years. The Company’s default tax withholding method for RSUs is the sell-to-cover method, in which shares with a market value equivalent to the tax withholding obligation are sold on behalf of the holder of the RSUs upon vesting and settlement to cover the tax withholding liability and the cash proceeds from such sales are remitted by the Company to taxing authorities. ESPP Activity and Valuation During the years ended December 31, 2020 and 2019, 164,164 and 77,684 shares of common stock were purchased, respectively, under the ESPP. The following assumptions were used to calculate the stock-based compensation for each stock purchase right granted under the ESPP during 2020: expected term of 0.5 years; expected volatility of 65.15 – 102.10%; risk-free interest rate of 0.1%; and a zero dividend yield. The resulting grant-date fair values were $8.12 and $4.29. The following assumptions were used to calculate the stock-based compensation for each stock purchase right granted under the ESPP during 2019: expected term of 0.4 – 0.5 years; expected volatility of 59.06 – 59.91%; risk-free interest rate of 1.6% - 2.1%; and a zero dividend yield. The resulting grant-date fair values were $3.48 and $5.01. Stock-based Compensation Expense The following is a summary of stock-based compensation expense by function (in thousands): Year Ended December 31, 2020 2019 2018 Costs of revenues $ 854 $ 480 $ 177 Research and development 1,773 903 429 Selling, general and administrative 5,611 3,475 711 Total stock-based compensation expense $ 8,238 $ 4,858 $ 1,317 The following is a summary of stock-based compensation expense by function (in thousands): Year Ended December 31, 2020 2019 2018 Stock options $ 4,729 $ 4,217 $ 1,317 Performance-based stock options 1,392 280 — RSUs 1,401 26 — ESPP 716 335 — Total stock-based compensation expense $ 8,238 $ 4,858 $ 1,317

Redeemable Convertible Prefer_2

Redeemable Convertible Preferred Stock Warrants	12 Months Ended
	Dec. 31, 2020
Convertible Preferred Stock Warrants [Abstract]
Redeemable Convertible Preferred Stock Warrants	Note 10. Redeemable Convertible Preferred Stock Warrants In September 2014, in connection with the Term Loan (see Note 6), the Company issued a warrant to purchase 22,489 shares of its Series B redeemable convertible preferred stock at an exercise price of $4.60 per share. In June 2017, as additional consideration for the Revolving Loan (see Note 6), the Company issued a warrant to purchase up to 62,096 shares of its Series C redeemable convertible preferred stock at an exercise price of $8.052. At initial recognition, the convertible preferred stock warrants were recorded at their estimated fair values ($0.1 million each initially) and were subject to remeasurement at each consolidated balance sheet date, with changes in fair value recognized as a component of net income. See Note 5 for the estimated fair values and changes in fair values relating to periods presented. Immediately prior to the closing of the Company’s IPO, the redeemable convertible preferred stock warrants automatically converted to common stock warrants. As a result of the automatic conversion of the redeemable convertible preferred stock warrants to common stock warrants, the Company revalued the redeemable convertible preferred stock warrants as of the completion of the IPO and reclassified the outstanding preferred stock warrant liability balance to additional paid-in capital with no further remeasurements as the common stock warrants are now deemed permanent equity. The fair value transferred to additional paid-in capital was $2.1 million. Subsequent to the conversion to a common stock warrant and before the end of the Company’s second quarter ended June 30, 2019, the warrant for 22,489 shares was exercised. The Company issued 19,069 shares of common stock as the warrant allowed a net share settlement. Separately, the warrant for 62,096 shares issued in June 2017 was exercised in August 2020. The Company issued 40,357 shares of common stock as the warrant allowed for a net share settlement.

Common Stock Warrants

Common Stock Warrants	12 Months Ended
	Dec. 31, 2020
Common Stock Warrants [Abstract]
Common Stock Warrants	Note 11. Common Stock Warrants In connection with the sale of Series A redeemable convertible preferred stock in August 2011, the Company issued a warrant to purchase 188,643 shares of common stock to an investor who purchased Series A redeemable convertible preferred stock in August 2011 at an exercise price of $0.04 per share. The Company recorded the issuance-date fair value of the warrant of $0.1 million in equity as the warrant met all criteria for equity classification. The common stock warrant was exercised in June 2019 prior to the Company’s IPO and is no longer outstanding. In connection with the Growth Capital Loan agreement (see Note 6), the Company issued a warrant to purchase 65,502 shares of common stock to the lender at an exercise price of $9.16 per share. The Company recorded the issuance-date fair value of the warrant of $0.6 million in equity as the warrant met all criteria for equity classification. The warrant was exercised in September 2020 and is no longer outstanding. The Company issued 39,415 shares of common stock as the warrant allowed for a net share settlement.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2020
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	Note 12 . Commitments and Contingencies Contingencies The Company is subject to claims and assessments from time to time in the ordinary course of business. Accruals for litigation and contingencies are reflected in the consolidated financial statements based on management’s assessment, including the advice of legal counsel, of the expected outcome of litigation or other dispute resolution proceedings and/or the expected resolution of contingencies. Liabilities for estimated losses are accrued if the potential losses from any claims or legal proceedings are considered probable and the amounts can be reasonably estimated. Significant judgment is required in both the determination of probability of loss and the determination as to whether the amount can be reasonably estimated. Accruals are based only on information available at the time of the assessment due to the uncertain nature of such matters. As additional information becomes available, management reassesses potential liabilities related to pending claims and litigation and may revise its previous estimates, which could materially affect the Company’s consolidated results of operations in a given period. As of December 31, 2020, the Company was not involved in any material legal proceedings. Indemnification In the normal course of business, the Company enters into contracts and agreements that contain a variety of representations and warranties and provide for general indemnifications. The Company’s exposure under these agreements is unknown because it involves claims that may be made against the Company in the future, but that have not yet been made. To date, the Company has not paid any claims or been required to defend any action related to its indemnification obligations. However, the Company may record charges in the future as a result of these indemnification obligations.

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 13. Net Loss per Share Attributable to Common Stockholders Basic net loss per share is computed by dividing the net loss by the weighted-average number of common shares outstanding for the period. Because the Company reported a net loss for all periods presented, the number of shares used to calculate diluted net loss per common share is the same as the number of shares used to calculate basic net loss per common share for those periods presented because the potentially dilutive shares would have been antidilutive if included in the calculation. The following table sets forth the computation of basic and diluted net loss per share attributable to common stockholders (in thousands, except share and per share data): Year Ended December 31, 2020 2019 2018 Numerator: Net loss attributable to common stockholders $ (41,280 ) $ (25,084 ) $ (19,886 ) Denominator: Weighted-average shares outstanding 34,374,903 18,011,955 3,063,516 Less: weighted-average shares subject to repurchase — (485 ) (359 ) Weighted-average shares outstanding used in computing net loss per share attributable to common stockholders—basic and diluted 34,374,903 18,011,470 3,063,157 Net loss per share attributable to common stockholders—basic and diluted $ (1.20 ) $ (1.39 ) $ (6.49 ) The following outstanding shares of potentially dilutive securities were excluded from the computation of diluted net loss per share attributable to common stockholders for the periods presented because including them would have been antidilutive: Year Ended December 31, 2020 2019 2018 Redeemable convertible preferred stock — — 18,474,742 Common stock warrants — 127,598 188,643 Series B preferred stock warrant — — 22,489 Series C preferred stock warrant — — 62,096 Options to purchase common stock 5,369,306 4,731,435 4,110,130 Unvested restricted stock units 619,218 120,000 — Employee stock purchase plan 58,802 75,405 — Unvested early exercised common stock options — — 262 Total 6,047,326 5,054,438 22,858,362

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2020
Income Tax Disclosure [Abstract]
Income Taxes	Note 14. Income Taxes For financial reporting purposes, loss before income taxes includes the following components (in thousands): Year Ended December 31, 2020 2019 2018 Domestic $ (41,404 ) $ (25,111 ) $ (19,897 ) Foreign 181 36 18 Loss before income taxes $ (41,223 ) $ (25,075 ) $ (19,879 ) Provision for Income Taxes The provision for income taxes consists of the following (in thousands): Year Ended December 31, 2020 2019 2018 Current: Federal $ — $ — $ — State 26 1 2 Foreign 31 8 5 Total current 57 9 7 Provision for income taxes $ 57 $ 9 $ 7 Income tax provision related to continuing operations differ from the amounts computed by applying the statutory income tax rate of 21% to pretax loss in 2020, 2019, and 2018 as follows: Year Ended December 31, 2020 2019 2018 Expected tax (benefit) at federal statutory rate (21 )% (21 )% (21 )% Effect of: State taxes (10 )% (8 )% (3 )% Change in valuation allowance 38 % 28 % 21 % Stock-based compensation (4 )% 2 % 1 % Research and development credit (3 )% (3 )% (3 )% Debt extinguishment – % – % 4 % Other – % 2 % 1 % Effective tax rate – % – % – % Tax Law Changes On March 27, 2020, the U.S. government enacted the Coronavirus Aid, Relief and Economic Security Act (“CARES Act”), which includes several U.S. income tax provisions related to, among other things, net operating loss carrybacks, alternative minimum tax credits, modifications to interest expense limitations, and an option to defer payroll tax payments for a limited period. Based on the guidance in the CARES Act, the Company deferred the payment of $0.7 million of certain payroll taxes to be paid in the future. The other provisions of the CARES Act did not have a significant impact on the Company’s consolidated financial statements. Deferred Tax Assets and Liabilities Deferred income taxes reflect the net tax effects of loss and credit carryforwards and temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes. Significant components of the Company’s deferred tax assets for federal and state income taxes are as follows (in thousands): December 31, 2020 2019 Deferred tax assets: Net operating loss carryforwards $ 43,221 $ 30,375 Research and development credits 8,455 6,190 Deferred revenue 695 2,154 Accruals 2,260 784 Stock-based compensation 2,157 787 Operating lease liabilities 3,198 574 Other intangibles 366 426 Other 96 114 Total gross deferred tax assets 60,448 41,404 Less: Valuation allowance (56,846 ) (40,000 ) Net deferred tax assets $ 3,602 $ 1,404 Deferred tax liabilities: Property and equipment (612 ) (875 ) Operating lease right-of-use assets (2,990 ) (529 ) Net deferred tax liabilities $ (3,602 ) $ (1,404 ) Realization of deferred tax assets is dependent upon future earnings, if any, the timing and amount of which are uncertain. Because of the Company’s lack of U.S. earnings history, the net U.S. deferred tax assets have been fully offset by a valuation allowance. The valuation allowance increased by $16.8 million and $7.6 million during the years ended December 31, 2020 and 2019, respectively. Net Operating Loss and Tax Credit Carryforwards As of December 31, 2020, the Company had a net operating loss carryforward for federal income tax purposes of approximately $159.2 million, portions of which will begin to expire in 2031. The Company had a total state net operating loss carryforward of approximately $112.7 million, which will begin to expire in 2031. Utilization of some of the federal and state net operating loss and credit carryforwards are subject to annual limitations due to the “change in ownership” provisions of the Internal Revenue Code of 1986, as amended, and similar state provisions. The annual limitations may result in the expiration of net operating losses and credits before utilization. As of December 31, 2020, the Company has federal credits of approximately $4.2 million, which will begin to expire in 2031 and state research credits of approximately $4.3 million, which have no expiration date. These tax credits are subject to the same limitations discussed above. Unrecognized Tax Benefits The Company has incurred net operating losses since inception and does not have any significant unrecognized tax benefits. The Company’s policy is to include interest and penalties related to unrecognized tax benefits, if any, within the provision for taxes in the consolidated statements of operations. If the Company is eventually able to recognize its uncertain positions, the effective tax rate would be reduced. The Company currently has a full valuation allowance against its net deferred tax asset, which would impact the timing of the effective tax rate benefit should any of these uncertain tax positions be favorably settled in the future. Any adjustments to the Company’s uncertain tax positions would result in an adjustment of net operating loss or tax credit carryforwards rather than resulting in a cash outlay. The Company files U.S. federal income tax returns and various state income tax returns. Because of net operating losses and research credit carryovers, substantially all the Company’s tax years remain open to examination. The Company has the following activity relating to unrecognized tax benefits (in thousands): December 31, 2020 2019 Beginning balance $ 1,581 $ 1,192 Gross increase—tax provision in current period 567 389 Ending balance $ 2,148 $ 1,581 Although it is reasonably possible that certain unrecognized tax benefits may increase or decrease within the next 12 months due to tax examination changes, settlement activities, expirations of statute of limitations, or the impact on recognition and measurement considerations related to the results of published tax cases or other similar activities, the Company does not anticipate any significant changes to unrecognized tax benefits over the next 12 months. During the years ended December 31, 2020, 2019, and 2018, no interest or penalties were required to be recognized relating to unrecognized tax benefits.

Subsequent Events

Subsequent Events	12 Months Ended
	Dec. 31, 2020
Subsequent Events [Abstract]
Subsequent Events	Note 15. Subsequent Events Subsequent to the annual period ended December 31, 2020 covered by this Annual Report, on January 29, 2021, we completed a follow-on offering in which we issued and sold 3,950,000 shares of common stock at a public offering price of $38.00 per share. We received net proceeds of $141.1 million after deducting underwriting discounts and commissions. The underwriters of the offering exercised their option to purchase an additional 592,500 shares shortly thereafter, resulting in additional net proceeds to us of $21.2 million after deducting underwriting discounts and commissions. In total, we raised net proceeds of $162.3 million after deducting underwriting discounts and commissions. We also incurred an estimated $0.4 million of offering expenses, including legal, accounting, printing and other offering-related costs.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2020
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”) and the applicable rules and regulations of the Securities and Exchange Commission (“SEC”) regarding annual reporting. The consolidated financial statements include the accounts of Personalis, Inc. and its wholly owned subsidiaries, Personalis (UK) Ltd. and Personalis (Shanghai) Ltd. All intercompany balances and transactions have been eliminated in consolidation. The Company began presenting “Long-term operating lease liabilities” and “Operating lease liabilities” separately in the consolidated balance sheets and consolidated statements of cash flows, respectively, in 2020. Amounts reported in previous periods were reclassified to conform to the current presentation.
Use of Estimates	Use of Estimates The preparation of consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, and disclosure of contingent assets and liabilities, at the date of the consolidated financial statements and the reported amounts of revenues and expenses during the reporting period. The estimates include, but are not limited to, useful lives assigned to long-lived assets, the valuation of common and convertible redeemable preferred stock and related warrants and options, the valuation of the compound derivative instrument, the valuation of stock-based awards, and provisions for income taxes and contingencies. Actual results could differ from these estimates, and such differences could be material to the Company’s consolidated financial position and results of operations.
Reverse Stock Split	Reverse Stock Split On June 4, 2019, the Company filed an amendment to the Company’s amended and restated certificate of incorporation to effect a reverse split of shares of the Company’s common stock and redeemable convertible preferred stock on a four-for-one basis (the “Reverse Stock Split”). The par value of the common stock and redeemable convertible preferred stock was not adjusted as a result of the Reverse Stock Split. All references to common stock, options to purchase common stock, share data, per share data, redeemable convertible preferred stock and related information contained in these consolidated financial statements have been retrospectively adjusted to reflect the effect of the Reverse Stock Split for all periods presented.
Initial Public Offering	Initial Public Offering On June 24, 2019, the Company completed an initial public offering (“IPO”) in which it issued and sold 9,109,725 shares of its common stock at a public offering price of $17.00 per share. The Company received net proceeds of $139.8 million after deducting underwriting discounts, commissions and offering expenses. Offering expenses were $4.2 million and consisted of fees and expenses incurred in connection with the sale of the Company’s common stock in the IPO, including legal, accounting, printing, and other IPO-related costs. A warrant to purchase 188,643 shares of our common stock was exercised prior to completion of the IPO. In addition, in connection with the IPO, all shares of the Company’s then-outstanding redeemable convertible preferred stock were automatically converted into 18,474,703 shares of the Company’s common stock, and all then-outstanding warrants to purchase the Company’s convertible preferred stock were automatically converted into warrants to purchase 84,585 shares of the Company’s common stock, all of which were exercised as of December 31, 2020 (see Note 10).
Follow-On Offering	Follow-On Offering On August 14, 2020, the Company completed a follow-on offering in which it issued and sold 6,578,947 shares of its common stock at a public offering price of $19.00 per share. The Company received net proceeds of $117.1 million after deducting underwriting discounts, commissions, and offering expenses. Offering expenses were $0.4 million consisting of legal, accounting, printing and other offering-related costs.
Concentration of Credit Risk and Other Risks and Uncertainties	Concentration of Credit Risk and Other Risks and Uncertainties The Company is subject to credit risk from its portfolio of cash and cash equivalents. The Company’s cash and cash equivalents are deposited with high-quality financial institutions. Deposits at these institutions may, at times, exceed federally insured limits. Management believes these financial institutions are financially sound and, accordingly, that minimal credit risk exists. The Company has not experienced any losses on its deposits of cash and cash equivalents. The Company also invests in investment ‑ ‑ The Company purchases various reagents and sequencing materials from sole source suppliers. Any extended interruption in the supply of these materials could result in the Company’s inability to secure sufficient materials to conduct business and meet customer demand. The Company routinely assesses the creditworthiness of its customers and does not require collateral. The Company has not experienced any material losses related to receivables from individual customers, or groups of customers. The Company maintains an allowance for doubtful accounts, which was $0.1 million as of December 31, 2020 and 2019. During the year ended December 31, 2019, bad debt expense was $0.1 million and included in selling, general and administrative expenses. The Company had no bad debt expense in 2020 and 2018. Significant customers are those that represent more than 10% of the Company’s total revenues or accounts receivable balance at each respective balance sheet date. For each significant customer, revenue as a percentage of total revenues and accounts receivable as a percentage of total accounts receivable are as follows: Revenues Accounts Receivable Year Ended December 31, December 31, 2020 2019 2018 2020 2019 VA MVP 71% 67% 49% * 19% Pfizer Inc. * 13% 10% * 23% Merck & Co., Inc. * * 12% 59% * Indivumed GmbH * * * * 30% * Less than 10% of revenues or accounts receivable
Revenue Recognition	Revenue Recognition The Company applies the revenue recognition guidance in accordance with Financial Accounting Standards Board (“FASB”) Accounting Standards Codification (“ASC”) Topic 606, Revenue from Contracts with Customers (“Topic 606”). Revenue Recognition The revenue guidance provides a five-step framework through which revenue is recognized when control of promised goods or services is transferred to a customer at an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. To determine revenue recognition for arrangements that the Company concludes are within the scope of Topic 606, management performs the following five steps: (i) identifies the contract(s) with a customer; (ii) identifies the performance obligations in the contract(s); (iii) determines the transaction price, including whether there are any constraints on variable consideration; (iv) allocates the transaction price to the performance obligations; and (v) recognizes revenue when (or as) the Company satisfies a performance obligation. At contract inception, once a contract is determined to be within the scope of the new revenue standard, the Company assesses whether individual goods or services promised within each contract are distinct and, therefore, represent separate performance obligations. The Company derives revenues from sequencing and data analysis services to support the development of personalized cancer vaccines and other next-generation cancer immunotherapies, as well as to support population sequencing initiatives. The Company’s contracts are in the form of a combination of signed agreements, statements of work, and/or purchase orders. Under Topic 606, the Company accounts for a contract with a customer when there is approval and commitment from both parties, the rights of the parties are identified, payment terms are identified, the contract has commercial substance, and it is probable that the Company will collect substantially all of the consideration to which it will be entitled. The sequencing and data analysis services are the only distinct services that meet the definition of a performance obligation and are accounted for as one performance obligation under Topic 606. The Company recognizes revenue from such services at the point in time when control of the test results is transferred to the customer. The Company has elected to exclude all sales and value added taxes from the measurement of the transaction price. Sequencing and data analysis services are based on a fixed price per test. Payment terms and conditions vary by contract and customer. The Company’s standard payment terms are less than 90 days from the invoice date. In instances where the timing of the Company’s revenue recognition differs from the timing of its invoicing, the Company does not assess whether a contract has a significant financing component if the expectation at contract inception is such that the period between payment by the customer and the transfer of the promised services to the customer will be one year or less. After assessing each of its revenue-generating arrangements to determine whether a significant financing component exists, the Company concluded that a significant financing component does not exist in any of its arrangements. The primary purpose of the Company’s invoicing terms is to provide customers with simplified and predictable ways of purchasing the Company’s services and to provide payment protection for the Company. Practical Expedients and Exemptions As a practical expedient, the Company recognizes the incremental costs of obtaining contracts, such as sales commissions, as an expense when incurred since the amortization period of the asset the Company otherwise would have recognized is one year or less. Sales commissions are recorded within selling, general, and administrative expenses in the consolidated statements of operations.
Costs of Revenues	Costs of Revenues Costs of revenues consist of raw materials costs, personnel costs (salaries, bonuses, benefits, payroll taxes, and stock-based compensation), laboratory supplies and consumables, depreciation and maintenance on equipment, and allocated facilities and information technology costs.
Research and Development Expenses	Research and Development Expenses The Company charges research and development costs to expenses as incurred, including lab and automation development costs. The expenses primarily consist of personnel costs (salaries, bonuses, stock-based compensation, payroll taxes, and benefits), laboratory supplies and consumables, costs of purchasing samples for research purposes, depreciation and maintenance on equipment, and allocated facilities and information technology costs.
Stock-Based Compensation	Stock-Based Compensation For options granted to employees, non-employees, and directors, stock-based compensation is measured at grant date based on the fair value of the award. The Company determines the grant-date fair value of the options using the Black-Scholes option-pricing model, except for certain performance-based awards for which an alternative valuation method may be used. The Company determines the fair value of restricted stock unit awards using the closing market price of the Company’s common stock on the date of grant. The grant-date fair value of awards is amortized over the employees’ requisite service period on a straight-line basis, or the non-employees’ vesting period as the goods are received or services rendered. Forfeitures are accounted for as they occur. Additionally, the Company’s 2019 Employee Stock Purchase Plan is deemed to be a compensatory plan and therefore is included in stock-based compensation expense. Inputs used in Black-Scholes option-pricing models to measure fair value of options are summarized as follows: Expected Term. The expected term is calculated using the simplified method, which is available if there is insufficient historical data about exercise patterns and post-vesting employment termination behavior. The simplified method is based on the vesting period and the contractual term for each grant, or for each vesting tranche for awards with graded vesting. The midpoint of the vesting date and the maximum contractual expiration date is used as the expected term under this method. For awards with multiple vesting tranches, the times from grant until the midpoints for each of the tranches may be averaged to provide an overall expected term. Expected Volatility. The Company used an average historical stock price volatility of a peer group of publicly traded companies to be representative of its expected future stock price volatility, as the Company did not have sufficient trading history for its common stock. For purposes of identifying these peer companies, the Company considered the industry, stage of development, size, and financial leverage of potential comparable companies. For each grant, the Company measured historical volatility over a period equivalent to the expected term. Risk-Free Interest Rate. The risk-free interest rate is based on the implied yield currently available on U.S. Treasury zero-coupon issues with remaining terms equivalent to the expected term of a stock award. Expected Dividend Rate. The Company has not paid and does not anticipate paying any dividends in the near future. Accordingly, the Company has estimated the dividend yield to be zero.
Foreign Currency Translation	Foreign Currency Translation The Company considers the functional currencies of its foreign subsidiaries to be the local currency. Assets and liabilities recorded in foreign currencies are translated at the exchange rate as of the balance sheet date, and costs and expenses are translated at average exchange rates in effect during the period. Equity transactions are translated using historical exchange rates. The effects of foreign currency translation adjustments are recorded as a separate component of accumulated other comprehensive income (loss) in the consolidated balance sheets.
Comprehensive Loss	Comprehensive Loss Comprehensive loss includes all changes in equity (net assets) during the period from nonowner sources. The Company’s comprehensive loss consists of its net loss, its cumulative translation adjustments, and its unrealized gains or losses on available-for-sale debt securities.
Income Taxes	Income Taxes The Company uses the asset and liability method under ASC Topic 740, Income Taxes, in accounting for income taxes. Deferred tax assets and liabilities are recognized for the estimated future tax consequences attributable to differences between the consolidated financial statement carrying amounts of existing assets and liabilities and their respective tax bases. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. Deferred tax expenses or benefits are the result of changes in the deferred tax assets and liabilities. Valuation allowances are established when necessary to reduce deferred tax assets where it is more likely than not that the deferred tax assets will not be realized. ASC Topic 740 clarifies the accounting for uncertainty in income taxes recognized in the financial statements. ASC Topic 740 provides that a tax benefit from an uncertain tax position may be recognized when it is more likely than not that the position will be sustained upon audit, including resolutions of any related appeals or litigation processes, based on the technical merits of the position. ASC Topic 740 also provides guidance on measurement, derecognition, classification, interest and penalties, accounting in interim periods, disclosure, and transition. The Company recognizes interest and penalties related to unrecognized tax benefits within the income tax expense line in the accompanying consolidated statements of operations. Accrued interest and penalties are included within the related liability line in the consolidated balance sheets.
Net Loss per Share Attributable to Common Stockholders	Net Loss per Share Attributable to Common Stockholders Basic net loss per common share is calculated by dividing the net loss attributable to common stockholders by the weighted-average number of shares of common stock outstanding during the period, without consideration of potentially dilutive securities. Diluted net loss per share is computed by dividing the net loss attributable to common stockholders by the weighted-average number of shares of common stock and potentially dilutive securities outstanding for the period. For purposes of the diluted net loss per share calculation, the redeemable convertible preferred stock, convertible preferred stock warrants, common stock warrants, common stock subject to repurchase, and equity awards are considered to be potentially dilutive securities. Basic and diluted net loss attributable to common stockholders per share is presented in conformity with the two-class method required for participating securities as the redeemable convertible preferred stock is considered a participating security. The Company’s participating securities do not have a contractual obligation to share in the Company’s losses. As such, the net loss is attributed entirely to common stockholders. Because the Company has reported a net loss for the reporting periods presented, the diluted net loss per common share is the same as basic net loss per common share for those periods.
Cash and Cash Equivalents	Cash and Cash Equivalents Cash equivalents consist of highly liquid investments with maturities at the time of purchase of three months or less. Cash equivalents include bank demand deposits and money market accounts that invest primarily in cash, U.S. Treasury bills, notes, and other obligations issued or guaranteed as to principal and interest by the U.S. Government, its agencies or instrumentalities, and repurchase agreements secured by such obligations or cash. Cash equivalents also include commercial paper, which are marketable debt securities recorded at fair value and accounted for in the same manner as other marketable debt securities described below.
Short-term Investments	Short-term Investments The Company’s investments in marketable debt securities are classified as available-for-sale and recorded at fair value. Investments with original maturities of greater than three months and remaining maturities of less than one year are classified as short-term investments. Investments with maturities beyond one year may be classified as short-term based on their highly liquid nature and because such marketable securities represent the investment of cash that is available for current operations. Short-term investments primarily consist of U.S. agency bonds, commercial paper, corporate bonds, asset-backed securities, and U.S. treasuries. Unrealized gains and losses are included in accumulated other comprehensive income (loss) in stockholders’ equity. Any discount or premium arising at purchase is accreted or amortized to interest income or expense. Realized gains and losses and declines in fair value, if any, judged to be other than temporary are reported in other income (expense), net. When securities are sold, any associated unrealized gain or loss initially recorded as a separate component of stockholders’ equity is reclassified out of stockholders’ equity on a specific-identification basis and recorded in earnings for the period. The Company periodically evaluates whether declines in fair values of its investments below their book values are other-than-temporary. This evaluation consists of several qualitative and quantitative factors regarding the severity and duration of the unrealized loss as well as the Company’s ability and intent to hold the marketable security until a forecasted recovery occurs. Factors considered include quoted market prices, recent financial results and operating trends, implied values from any recent transactions or offers of investee securities, credit quality of debt instrument issuers, other publicly available information that may affect the value of the marketable security, duration and severity of the decline in value, and management’s strategy and intentions for holding the marketable security. To date, the Company has not recorded any impairment charges on its marketable securities related to other-than-temporary declines in market value.
Fair Value Measurements	Fair Value Measurements Financial assets and liabilities are recorded at fair value. Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability (an exit price) in an orderly transaction between market participants at the reporting date. The hierarchy below lists three levels of fair value based on the extent to which inputs used in measuring fair value are observable in the market. Observable inputs reflect market data obtained from independent sources while unobservable inputs reflect market assumptions made by the reporting entity. The three-level hierarchy for the inputs to valuation techniques used to measure fair value is briefly summarized as follows: Level 1 — Unadjusted quoted prices in active markets that are accessible to the reporting entity at the measurement date for identical assets and liabilities. Level 2 — Inputs other than quoted prices in active markets for identical assets and liabilities that are observable either directly or indirectly for substantially the full term of the asset or liability. Level 2 inputs include the following: • Quoted prices for similar assets and liabilities in active markets. • Quoted prices for identical or similar assets or liabilities in markets that are not active. • Observable inputs other than quoted prices that are used in the valuation of the assets or liabilities (e.g., interest rate and yield curve quotes at commonly quoted intervals). • Inputs that are derived principally from or are corroborated by observable market data by correlation or other means. Level 3 — Unobservable inputs for the assets or liabilities (i.e., supported by little or no market activity). Level 3 inputs include management’s own assumptions about the assumptions that market participants would use in pricing the asset or liability (including assumptions about risk). This hierarchy requires the Company to use observable market data, when available, and to minimize the use of unobservable inputs when determining fair value.
Accounts Receivable, Net	Accounts Receivable, Net Trade accounts receivable are recorded at the invoiced amount and are noninterest bearing. At each reporting period, management reviews all outstanding customer balances to determine if the facts and circumstances of each customer relationship indicate the need for a reserve. A reserve is recorded when it is probable that a loss has been incurred based on past events and conditions existing at the date of the financial statements, and the loss is reasonably estimated.
Inventory and Other Deferred Costs	Inventory and Other Deferred Costs Inventory, consisting of supplies used in the Company’s genomic analysis contracts, are valued at the lower of cost or net realizable value. Cost is determined using actual costs, on a first-in, first-out basis. Other deferred costs relate to work in process for costs incurred on genomic analysis contracts that have not been completed or recognized as revenues. Other deferred costs represent materials used in sequencing services, labor, and overhead allocations.
Property and Equipment, Net	Property and Equipment, Net Property and equipment are recorded at cost, less accumulated depreciation and amortization, and are depreciated on a straight-line basis over the estimated useful lives of the related assets, which is generally three to five years for computer equipment, two years for software, three years for furniture and equipment, and five years for machinery and equipment. Leasehold improvements are amortized over the shorter of the lease term or the estimated useful life of the related asset. Upon retirement or sale, the cost and related accumulated depreciation and amortization are removed from the consolidated balance sheet, and the resulting gain or loss is reflected in the consolidated statements of operations. Maintenance and repairs that are not considered improvements and do not extend the useful lives of the assets are charged to expense as incurred. Construction-in-process assets consist primarily of computer equipment and machinery and equipment that have not yet been placed in service. These assets are stated at cost and are not depreciated. Once the assets are placed into service, assets are reclassified to the appropriate asset class based on their nature and depreciated in accordance with the useful lives above.
Leases	Leases The Company categorizes leases with contractual terms longer than twelve months as either operating or finance leases. Finance leases are generally those leases that allow the Company to substantially utilize or pay for the entire asset over its estimated life. All other leases are categorized as operating leases. As of December 31, 2020, the Company had no finance leases. Certain lease contracts include obligations to pay for other services, such as maintenance. The Company elected to account for these other services as a component of the lease (i.e., the Company elected the practical expedient not to separate lease and non-lease components). Lease liabilities are recognized at the present value of the fixed lease payments, reduced by landlord incentives, using a discount rate based on the Company’s current borrowing rate at the lease commencement date, adjusted for various factors including level of collateralization and term (the “incremental borrowing rate”), unless the rate implicit in the lease is readily determinable. The current portion of lease liabilities is included in “Accrued and other current liabilities.” Lease assets are recognized based on the initial present value of the fixed lease payments, reduced by landlord incentives, plus any direct costs from executing the leases or lease prepayments reclassified from “Other long-term assets” upon lease commencement. Lease assets are presented as “Operating lease right-of-use assets” as a long-term asset. Leasehold improvements are capitalized at cost and amortized over the lesser of their expected useful life or the lease term. Costs associated with operating lease assets are recognized on a straight-line basis within operating expenses over the term of the lease. The Company has made an accounting policy election not to recognize right-of-use assets and lease liabilities that arise from leases with a term of 12 months or less. Lease payments are recognized as an expense on a straight-line basis over the lease term.
Recent Accounting Pronouncements	Recent Accounting Pronouncements New Accounting Pronouncements Not Yet Adopted In June 2016, the FASB issued Accounting Standards Update (“ASU”) No. 2016-13, Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments, which amends the impairment model by requiring entities to use a forward-looking approach based on expected losses to estimate credit losses on certain types of financial instruments, including trade receivables. The accounting update also made minor changes to the impairment model for available-for-sale debt securities. In November of 2019, the FASB delayed the effective date for Smaller Reporting Companies to the first quarter of 2023. The Company is currently evaluating the impact of the new guidance on its consolidated financial statements and related disclosures. The Company will apply the new guidance by means of a cumulative-effect adjustment to the opening retained earnings as of the beginning of the first reporting period in which the guidance is effective.
JOBS Act Accounting Election	JOBS Act Accounting Election The Company is an emerging growth company, as defined in the Jumpstart Our Business Startups Act (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 irrevocably elected not to avail itself of this exemption from new or revised accounting standards, and therefore, the Company will be subject to the same new or revised accounting standards as other public companies that are not emerging growth companies.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2020
Accounting Policies [Abstract]
Schedule of Percentage of Revenues and Accounts Receivables from Customers	For each significant customer, revenue as a percentage of total revenues and accounts receivable as a percentage of total accounts receivable are as follows: Revenues Accounts Receivable Year Ended December 31, December 31, 2020 2019 2018 2020 2019 VA MVP 71% 67% 49% * 19% Pfizer Inc. * 13% 10% * 23% Merck & Co., Inc. * * 12% 59% * Indivumed GmbH * * * * 30% * Less than 10% of revenues or accounts receivable

Revenues (Tables)

Revenues (Tables)	12 Months Ended
	Dec. 31, 2020
Disaggregation Of Revenue [Abstract]
Schedule of Revenues Disaggregated by Customer Type	The following table presents the Company’s revenues disaggregated by customer type (in thousands): Year Ended December 31, 2020 2019 2018 VA MVP $ 56,154 $ 43,545 $ 18,601 All other customers 22,494 21,662 19,173 Total $ 78,648 $ 65,207 $ 37,774

Balance Sheet Details (Tables)

Balance Sheet Details (Tables)	12 Months Ended
	Dec. 31, 2020
Balance Sheet Related Disclosures [Abstract]
Schedule of Inventory and Other Deferred Costs	Inventory and other deferred costs consist of the following (in thousands): December 31, 2020 2019 Raw materials $ 2,675 $ 1,424 Other deferred costs 2,964 3,182 Total inventory and other deferred costs $ 5,639 $ 4,606
Schedule of Property and Equipment, Net	Property and equipment, net consists of the following (in thousands): December 31, 2020 2019 Machinery and equipment $ 13,854 $ 12,511 Computer equipment 10,467 8,855 Furniture and fixtures 440 368 Leasehold improvement 987 987 Computer software costs 278 198 Construction in progress 322 234 Total 26,348 23,153 Less: Accumulated depreciation and amortization (14,514 ) (9,047 ) Property and equipment, net $ 11,834 $ 14,106
Schedule of Accrued and Other Current Liabilities	Accrued and other current liabilities consist of the following (in thousands): December 31, 2020 2019 Accrued compensation $ 8,041 $ 4,147 Operating lease liabilities 2,445 1,361 Accrued liabilities 313 689 Accrued taxes 95 210 Other current liabilities 407 241 Total accrued and other current liabilities $ 11,301 $ 6,648

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2020
Fair Value Disclosures [Abstract]
Schedule of Financial Assets and Liabilities Measured at Fair Value on Recurring Basis and Level of Inputs used in such Measurements	The following tables show the Company’s financial assets and liabilities measured at fair value on a recurring basis and the level of inputs used in such measurements as of December 31, 2020 and 2019 (in thousands): December 31, 2020 Adjusted Cost Unrealized Gains Unrealized Losses Fair Value Fair Value Level Assets Cash and cash equivalents: Cash $ 4,767 $ — $ — $ 4,767 Money market funds 22,614 — — 22,614 Level 1 Commercial paper 41,145 — (1 ) 41,144 Level 2 Total cash and cash equivalents 68,526 — (1 ) 68,525 Short-term investments: Commercial paper 25,470 — — 25,470 Level 2 U.S. government securities 18,260 1 — 18,261 Level 2 Corporate debt securities 29,576 — (8 ) 29,568 Level 2 U.S. agency securities 61,436 31 (1 ) 61,466 Level 2 Total short-term investments 134,742 32 (9 ) 134,765 Total assets measured at fair value $ 203,268 $ 32 $ (10 ) $ 203,290 December 31, 2019 Adjusted Cost Unrealized Gains Unrealized Losses Fair Value Fair Value Level Assets Cash and cash equivalents: Cash $ 1,271 $ — $ — $ 1,271 Money market funds 12,495 — — 12,495 Level 1 Commercial paper 41,281 — (1 ) 41,280 Level 2 Total cash and cash equivalents 55,047 — (1 ) 55,046 Short-term investments: Commercial paper 17,898 — (6 ) 17,892 Level 2 U.S. government securities 4,011 — — 4,011 Level 2 Corporate debt securities 13,953 1 (6 ) 13,948 Level 2 U.S. agency securities 32,776 20 (2 ) 32,794 Level 2 Asset-backed securities 4,598 — — 4,598 Level 2 Total short-term investments 73,236 21 (14 ) 73,243 Total assets measured at fair value $ 128,283 $ 21 $ (15 ) $ 128,289
Schedule of Risk-free Interest Rate Based on U.S. Treasury Yield Curve Over Expected Term of Warrants	The risk-free interest rate was based on the U.S. Treasury yield curve over the expected term of the warrants. Period Ended Year Ended June 24, 2019 December 31, 2018 Expected term (in years) 5.01 - 5.26 5.17 - 7.00 Volatility 57.20% - 57.24% 55.56% - 56.42% Risk-free interest rate 1.75% 2.58% - 3.01% Dividend yield –% –%
Summary of Changes in Fair Value of Level 3 Financial Instruments	The following table sets forth a summary of the changes in the fair value of the Company’s Level 3 financial instruments (in thousands): Warrant Liability Derivative Asset Derivative Liability Balance — December 31, 2017 $ 292 $ — $ 671 Initial fair value of derivative asset — 623 — Change in fair value 391 (97 ) (671 ) Elimination as a result of debt extinguishment — (526 ) — Balance — December 31, 2018 683 — — Change in fair value 1,403 — — Reclassification of warrant liability to additional paid-in capital on conversion (2,086 ) — — Balance — December 31, 2019 $ — $ — $ —

Leases (Tables)

Leases (Tables)	12 Months Ended
	Dec. 31, 2020
Leases [Abstract]
Schedule of Future Minimum Lease Payments	As of December 31, 2020, the Company’s operating leases had a weighted-average remaining lease term of 6.4 years and a weighted-average discount rate of 10.7%. The Company’s discount rates are based on estimates of its incremental borrowing rate, as the discount rates implicit in the Company’s lease cannot be readily determined. Future lease payments under operating leases as of December 31, 2020 were as follows (in thousands): Amount 2021 $ 2,558 2022 2,194 2023 2,047 2024 2,113 2025 2,182 2026 and thereafter 4,378 Total future minimum lease payments 15,472 Less: imputed interest (4,486 ) Present value of future minimum lease payments 10,986 Less: current portion of operating lease liability (2,445 ) Long-term operating lease liabilities $ 8,541

Redeemable Convertible Prefer_3

Redeemable Convertible Preferred Stock (Tables)	12 Months Ended
	Dec. 31, 2020
Temporary Equity Disclosure [Abstract]
Summary of Redeemable Convertible Preferred Stock Outstanding	Series A redeemable convertible preferred stock, Series B redeemable convertible preferred stock, and Series C redeemable convertible preferred stock (collectively the “Redeemable Convertible Preferred Stock”) outstanding consisted of the following as of December 31, 2018 and as of immediately prior to the automatic conversion of the Redeemable Convertible Preferred Stock into common stock: December 31, 2018 Shares Authorized Shares Issued and Outstanding Aggregate Liquidation Preference Net Carrying Value (in thousands) Series A 31,250,000 7,812,497 $ 20,500 $ 20,261 Series B 19,288,150 4,799,548 22,078 22,047 Series C 24,700,000 5,862,697 47,206 47,096 Total redeemable convertible preferred stock 75,238,150 18,474,742 $ 89,784 $ 89,404

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2020
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Summary of Shares of Common Stock Available for Issuance	Shares of common stock available for issuance under the Company’s equity incentive plans at December 31, 2020 and December 31, 2019 were as follows: December 31, 2020 2019 Reserved for issuance upon exercise of options outstanding under the 2011 Plan 3,389,711 4,474,057 Reserved for issuance upon exercise or settlement of awards outstanding under the 2019 Plan 2,399,513 377,378 Reserved and available for issuance under the 2019 Plan 1,977,069 2,392,343 Reserved for issuance upon exercise or settlement of awards outstanding under the Inducement Plan 199,300 — Reserved and available for issuance under the Inducement Plan 800,700 — Reserved and available for issuance under the ESPP 320,582 172,316 Total number of shares reserved 9,086,875 7,416,094
Summary of Stock Option Activity	A summary of the Company’s stock option activity (excluding performance-based stock option activity summarized further below) under the 2011 Plan, 2019 Plan, and Inducement Plan for the years ended December 31, 2020, 2019 and 2018 is as follows: Outstanding Options (in thousands, except share and per share data) Number of Shares Weighted- Average Exercise Price Weighted- Average Remaining Contractual Term (in years) Aggregate Intrinsic Value Balance—December 31, 2017 2,884,527 $ 1.92 6.61 $ 5,860 Options granted 1,386,464 5.68 Options exercised (34,426 ) 2.80 96 Options cancelled (126,435 ) 2.96 Balance—December 31, 2018 4,110,130 $ 3.16 6.94 $ 24,716 Options granted 988,913 11.81 Options exercised (287,932 ) 2.47 Options cancelled (79,676 ) 6.61 Balance—December 31, 2019 4,731,435 $ 4.94 6.60 $ 29,730 Options granted 1,357,741 12.05 Options exercised (908,691 ) 3.07 Options cancelled (232,179 ) 7.87 Balance—December 31, 2020 4,948,306 $ 7.10 6.71 $ 146,044 Options vested and exercisable as of December 31, 2020 2,868,867 $ 4.24 5.21 $ 92,879
Summary of Weighted-average Assumptions Used in Determination of Fair Value of Stock Options	The fair value of stock options was estimated using the following weighted-average assumptions: Year Ended December 31, 2020 2019 2018 Expected term (in years) 5.50 - 6.40 5.00 - 6.87 1.50 - 6.35 Volatility 61.74 - 68.18% 56.20 - 63.08% 52.19 - 56.47% Risk-free interest rate 0.36 - 1.66% 1.53 - 2.52% 2.62 - 2.88% Dividend yield –% –% –%
Summary of Restricted Stock Units Activity	A summary of the Company’s RSU activity under the 2019 Plan and Inducement Plan for the years ended December 31, 2020 and 2019 is as follows: Unvested Restricted Stock Units (in thousands, except share and per share data) Number of Shares Weighted- Average Grant Date Fair Value Aggregate Fair Value Balance—December 31, 2018 — $ — RSUs granted 120,000 8.86 RSUs vested — — RSUs cancelled — — Balance—December 31, 2019 120,000 $ 8.86 $ 1,308 RSUs granted 648,000 9.93 RSUs vested (130,945 ) 7.09 2,991 RSUs cancelled (17,837 ) 6.83 Balance—December 31, 2020 619,218 $ 10.41 $ 22,670
Stock Based Compensation Expense by Function	The following is a summary of stock-based compensation expense by function (in thousands): Year Ended December 31, 2020 2019 2018 Costs of revenues $ 854 $ 480 $ 177 Research and development 1,773 903 429 Selling, general and administrative 5,611 3,475 711 Total stock-based compensation expense $ 8,238 $ 4,858 $ 1,317 The following is a summary of stock-based compensation expense by function (in thousands): Year Ended December 31, 2020 2019 2018 Stock options $ 4,729 $ 4,217 $ 1,317 Performance-based stock options 1,392 280 — RSUs 1,401 26 — ESPP 716 335 — Total stock-based compensation expense $ 8,238 $ 4,858 $ 1,317
Performance-Based Stock Option | 2019 Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Summary of Stock Option Activity	A summary of the Company’s performance-based stock option activity under the 2019 Plan for the year ended December 31, 2020 is as follows: Outstanding Performance-Based Options (in thousands, except share and per share data) Number of Shares Weighted- Average Exercise Price Weighted- Average Remaining Contractual Term (in years) Aggregate Intrinsic Value Balance—December 31, 2019 — $ — — $ — Options granted 421,000 5.10 Options exercised — Options cancelled — Balance—December 31, 2020 421,000 $ 5.10 9.21 $ 13,266 Options vested and exercisable as of December 31, 2020 421,000 $ 5.10 9.21 $ 13,266
Summary of Weighted-average Assumptions Used in Determination of Fair Value of Stock Options	The Company estimated the fair value of the PSO using a Monte Carlo Model and the following assumptions and estimates: 2020 Performance period (in years) 10.00 Derived service period (in years) 4.55 Volatility 63.60 % Risk-free interest rate 1.02 % Dividend yield –% Estimated fair value (per share) $ 3.31

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]
Schedule of Basic and Diluted Net Loss per Share	The following table sets forth the computation of basic and diluted net loss per share attributable to common stockholders (in thousands, except share and per share data): Year Ended December 31, 2020 2019 2018 Numerator: Net loss attributable to common stockholders $ (41,280 ) $ (25,084 ) $ (19,886 ) Denominator: Weighted-average shares outstanding 34,374,903 18,011,955 3,063,516 Less: weighted-average shares subject to repurchase — (485 ) (359 ) Weighted-average shares outstanding used in computing net loss per share attributable to common stockholders—basic and diluted 34,374,903 18,011,470 3,063,157 Net loss per share attributable to common stockholders—basic and diluted $ (1.20 ) $ (1.39 ) $ (6.49 )
Schedule of Dilutive Securities Excluded from Computation of Diluted Net Loss per Share	The following outstanding shares of potentially dilutive securities were excluded from the computation of diluted net loss per share attributable to common stockholders for the periods presented because including them would have been antidilutive: Year Ended December 31, 2020 2019 2018 Redeemable convertible preferred stock — — 18,474,742 Common stock warrants — 127,598 188,643 Series B preferred stock warrant — — 22,489 Series C preferred stock warrant — — 62,096 Options to purchase common stock 5,369,306 4,731,435 4,110,130 Unvested restricted stock units 619,218 120,000 — Employee stock purchase plan 58,802 75,405 — Unvested early exercised common stock options — — 262 Total 6,047,326 5,054,438 22,858,362

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2020
Income Tax Disclosure [Abstract]
Schedule of Loss Before Income Taxes	For financial reporting purposes, loss before income taxes includes the following components (in thousands): Year Ended December 31, 2020 2019 2018 Domestic $ (41,404 ) $ (25,111 ) $ (19,897 ) Foreign 181 36 18 Loss before income taxes $ (41,223 ) $ (25,075 ) $ (19,879 )
Schedule of Provision for Income Taxes	The provision for income taxes consists of the following (in thousands): Year Ended December 31, 2020 2019 2018 Current: Federal $ — $ — $ — State 26 1 2 Foreign 31 8 5 Total current 57 9 7 Provision for income taxes $ 57 $ 9 $ 7
Summary of Income Tax Provision Related to Continuing Operations Statutory Income Tax Rate	Income tax provision related to continuing operations differ from the amounts computed by applying the statutory income tax rate of 21% to pretax loss in 2020, 2019, and 2018 as follows: Year Ended December 31, 2020 2019 2018 Expected tax (benefit) at federal statutory rate (21 )% (21 )% (21 )% Effect of: State taxes (10 )% (8 )% (3 )% Change in valuation allowance 38 % 28 % 21 % Stock-based compensation (4 )% 2 % 1 % Research and development credit (3 )% (3 )% (3 )% Debt extinguishment – % – % 4 % Other – % 2 % 1 % Effective tax rate – % – % – %
Components of Deferred Tax Assets for Federal and State Income Taxes	Significant components of the Company’s deferred tax assets for federal and state income taxes are as follows (in thousands): December 31, 2020 2019 Deferred tax assets: Net operating loss carryforwards $ 43,221 $ 30,375 Research and development credits 8,455 6,190 Deferred revenue 695 2,154 Accruals 2,260 784 Stock-based compensation 2,157 787 Operating lease liabilities 3,198 574 Other intangibles 366 426 Other 96 114 Total gross deferred tax assets 60,448 41,404 Less: Valuation allowance (56,846 ) (40,000 ) Net deferred tax assets $ 3,602 $ 1,404 Deferred tax liabilities: Property and equipment (612 ) (875 ) Operating lease right-of-use assets (2,990 ) (529 ) Net deferred tax liabilities $ (3,602 ) $ (1,404 )
Summary of Unrecognized Tax Benefits	The Company has the following activity relating to unrecognized tax benefits (in thousands): December 31, 2020 2019 Beginning balance $ 1,581 $ 1,192 Gross increase—tax provision in current period 567 389 Ending balance $ 2,148 $ 1,581

Company and Nature of Business

Company and Nature of Business - Additional Information (Details)	12 Months Ended
	Dec. 31, 2020Segment
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Number of reportable segments	1

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Additional Information (Details)	Aug. 14, 2020USD ($)$ / sharesshares	Jun. 24, 2019USD ($)$ / sharesshares	Dec. 31, 2020USD ($)	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)
Summary Of Significant Accounting Policies [Line Items]
Reverse stock split of common stock, description			four-for-one
Reverse stock split of common stock, ratio				0.25
Offering expenses				$ 4,200,000
Conversion from convertible warrants | shares		188,643
Allowance for doubtful accounts			$ 100,000	$ 0.1
Bad debt expense			$ 0		$ 0
Dividend yield			0.00%	0.00%	0.00%
Dividends			$ 0
Software
Summary Of Significant Accounting Policies [Line Items]
Property and equipment estimated useful lives			2 years
Furniture and Equipment
Summary Of Significant Accounting Policies [Line Items]
Property and equipment estimated useful lives			3 years
Machinery and Equipment
Summary Of Significant Accounting Policies [Line Items]
Property and equipment estimated useful lives			5 years
Minimum | Computer Equipment
Summary Of Significant Accounting Policies [Line Items]
Property and equipment estimated useful lives			3 years
Minimum | ASU 2014-09
Summary Of Significant Accounting Policies [Line Items]
Standard payment terms			90 days
Maximum | Computer Equipment
Summary Of Significant Accounting Policies [Line Items]
Property and equipment estimated useful lives			5 years
Maximum | ASU 2014-09
Summary Of Significant Accounting Policies [Line Items]
Period between payment by customer and transfer of promised services			1 year
Recognition period of incremental costs			1 year
Selling, General and Administrative Expenses
Summary Of Significant Accounting Policies [Line Items]
Bad debt expense				$ 100,000
IPO
Summary Of Significant Accounting Policies [Line Items]
Reverse stock split of common stock, description			The Reverse Stock Split was effected on a holder-by-holder basis with no fractional shares issued, which resulted in 39 fewer shares of common stock issued as compared to the amounts shown in the above table
Number of shares issued | shares		9,109,725
Shares issued price per share | $ / shares		$ 17
Proceeds from issuance of common stock after deducting underwriting discounts, commissions and offering expenses upon completion of initial public offering		$ 139,800,000
Conversion from convertible common stock | shares		18,474,703
IPO | Convertible Preferred Stock
Summary Of Significant Accounting Policies [Line Items]
Conversion from convertible warrants to purchase common stock | shares		84,585
Follow - On Offering
Summary Of Significant Accounting Policies [Line Items]
Number of shares issued | shares	6,578,947
Shares issued price per share | $ / shares	$ 19
Proceeds from Issuance or Sale of Equity	$ 117,100,000
Offering expenses incurred	$ 400,000

Summary of Significant Accoun_5

Summary of Significant Accounting Policies - Schedule of Percentage of Revenues and Accounts Receivables from Customers (Details)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
VA MVP
Summary Of Significant Accounting Policies [Line Items]
Concentration risk percentage	71.00%
Revenue | VA MVP | Customer
Summary Of Significant Accounting Policies [Line Items]
Concentration risk percentage		67.00%	49.00%
Revenue | Merck & Co., Inc. | Customer
Summary Of Significant Accounting Policies [Line Items]
Concentration risk percentage			12.00%
Revenue | Pfizer Inc. | Customer
Summary Of Significant Accounting Policies [Line Items]
Concentration risk percentage		13.00%	10.00%
Accounts Receivable | VA MVP | Customer
Summary Of Significant Accounting Policies [Line Items]
Concentration risk percentage		19.00%
Accounts Receivable | Indivumed GmbH | Customer
Summary Of Significant Accounting Policies [Line Items]
Concentration risk percentage		30.00%
Accounts Receivable | Merck & Co., Inc. | Customer
Summary Of Significant Accounting Policies [Line Items]
Concentration risk percentage	59.00%
Accounts Receivable | Pfizer Inc. | Customer
Summary Of Significant Accounting Policies [Line Items]
Concentration risk percentage		23.00%

Summary of Significant Accoun_6

Summary of Significant Accounting Policies - Schedule of Percentage of Revenues and Accounts Receivables from Customers (Parenthetical) (Details)	12 Months Ended
	Dec. 31, 2020
Accounts Receivable | Minimum | Customer
Summary Of Significant Accounting Policies [Line Items]
Concentration risk percentage	10.00%

Revenues - Schedule of Revenues

Revenues - Schedule of Revenues Disaggregated by Customer Type (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Disaggregation Of Revenue [Line Items]
Revenues	$ 78,648	$ 65,207	$ 37,774
VA MVP
Disaggregation Of Revenue [Line Items]
Revenues	56,154	43,545	18,601
All Other Customers
Disaggregation Of Revenue [Line Items]
Revenues	$ 22,494	$ 21,662	$ 19,173

Revenues - Additional Informati

Revenues - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Disaggregation Of Revenue [Line Items]
Contract assets		$ 0	$ 0
Contract liabilities	$ 21,000,000	36,000,000
Contract liability, revenue recognized	$ 33,800,000	$ 35,400,000	$ 16,000,000
Customer Concentration Risk | Revenues | Maximum | Outside of United States
Disaggregation Of Revenue [Line Items]
Revenue	5.00%	4.00%	3.00%

Revenues - Additional Informa_2

Revenues - Additional Information (Details 1) - Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2021-01-01 $ in Millions	Dec. 31, 2020USD ($)
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Remaining performance obligation, amount	$ 43.5
Remaining performance obligation, expected time of satisfaction	9 months
Maximum
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Revenue, remaining performance obligation, optional exemption, remaining duration	1 year

Balance Sheet Details - Schedul

Balance Sheet Details - Schedule of Inventory and Other Deferred Costs (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Inventory And Other Deferred Costs [Abstract]
Raw materials	$ 2,675	$ 1,424
Other deferred costs	2,964	3,182
Total inventory and other deferred costs	$ 5,639	$ 4,606

Balance Sheet Details - Sched_2

Balance Sheet Details - Schedule of Property and Equipment, Net (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Property Plant And Equipment [Line Items]
Total	$ 26,348	$ 23,153
Less: Accumulated depreciation and amortization	(14,514)	(9,047)
Property and equipment, net	11,834	14,106
Machinery and Equipment
Property Plant And Equipment [Line Items]
Total	13,854	12,511
Computer Equipment
Property Plant And Equipment [Line Items]
Total	10,467	8,855
Furniture and Fixtures
Property Plant And Equipment [Line Items]
Total	440	368
Leasehold Improvement
Property Plant And Equipment [Line Items]
Total	987	987
Computer Software Costs
Property Plant And Equipment [Line Items]
Total	278	198
Construction in Progress
Property Plant And Equipment [Line Items]
Total	$ 322	$ 234

Balance Sheet Details - Additio

Balance Sheet Details - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Statement [Abstract]
Depreciation and amortization expense	$ 5,758	$ 4,748	$ 3,066

Balance Sheet Details - Sched_3

Balance Sheet Details - Schedule of Accrued and Other Current Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Payables And Accruals [Abstract]
Accrued compensation	$ 8,041	$ 4,147
Operating lease liabilities	$ 2,445	$ 1,361
Operating Lease, Liability, Current, Statement of Financial Position [Extensible List]	psnl:AccruedLiabilitiesAndOtherLiabilitiesCurrent	psnl:AccruedLiabilitiesAndOtherLiabilitiesCurrent
Accrued liabilities	$ 313	$ 689
Accrued taxes	95	210
Other current liabilities	407	241
Total accrued and other current liabilities	$ 11,301	$ 6,648

Fair Value Measurements - Sched

Fair Value Measurements - Schedule of Financial Assets and Liabilities Measured at Fair Value on Recurring Basis and Level of Inputs used in such Measurements (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Assets
Cash and cash equivalents, Adjusted Cost	$ 68,525	$ 55,046
Fair Value Measurements Recurring
Assets
Assets, Adjusted Cost	203,268	128,283
Assets, Unrealized Gains	32	21
Assets, Unrealized Losses	(10)	(15)
Assets, Fair Value	203,290	128,289
Cash and cash equivalents, Adjusted Cost	68,526	55,047
Cash and cash equivalents, Unrealized Losses	(1)	(1)
Cash and cash equivalents, Fair Value	68,525	55,046
Fair Value Measurements Recurring | Short-term Investments
Assets
Investments, Adjusted Cost	134,742	73,236
Investments, Unrealized Gains	32	21
Investments, Unrealized Losses	(9)	(14)
Investments, Fair Value	134,765	73,243
Fair Value Measurements Recurring | Commercial Paper | Level 2
Assets
Cash and cash equivalents, Adjusted Cost	41,145	41,281
Cash and cash equivalents, Unrealized Losses	(1)	(1)
Cash and cash equivalents, Fair Value	41,144	41,280
Fair Value Measurements Recurring | Commercial Paper | Level 2 | Short-term Investments
Assets
Investments, Adjusted Cost	25,470	17,898
Investments, Unrealized Losses		(6)
Investments, Fair Value	25,470	17,892
Fair Value Measurements Recurring | U.S. Government Securities | Level 2 | Short-term Investments
Assets
Investments, Adjusted Cost	18,260	4,011
Investments, Unrealized Gains	1
Investments, Fair Value	18,261	4,011
Fair Value Measurements Recurring | Corporate Debt Securities | Level 2 | Short-term Investments
Assets
Investments, Adjusted Cost	29,576	13,953
Investments, Unrealized Gains		1
Investments, Unrealized Losses	(8)	(6)
Investments, Fair Value	29,568	13,948
Fair Value Measurements Recurring | U.S. Agency Securities | Level 2 | Short-term Investments
Assets
Investments, Adjusted Cost	61,436	32,776
Investments, Unrealized Gains	31	20
Investments, Unrealized Losses	(1)	(2)
Investments, Fair Value	61,466	32,794
Fair Value Measurements Recurring | Asset-backed Securities | Level 2 | Short-term Investments
Assets
Investments, Adjusted Cost		4,598
Investments, Fair Value		4,598
Fair Value Measurements Recurring | Cash
Assets
Cash and cash equivalents, Adjusted Cost	4,767	1,271
Cash and cash equivalents, Fair Value	4,767	1,271
Fair Value Measurements Recurring | Money Market Funds | Level 1
Assets
Cash and cash equivalents, Adjusted Cost	22,614	12,495
Cash and cash equivalents, Fair Value	$ 22,614	$ 12,495

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Details)	12 Months Ended
	Dec. 31, 2020USD ($)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Realized gains or losses on sales of marketable securities	$ 0
Unrealized loss position for 12 months or greater on security	$ 0
Minimum
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Long-term marketable debt securities maturity period	14 months
Maximum
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Long-term marketable debt securities maturity period	23 months
Long-term Investments
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Debt securities, aggregate cost basis	$ 21,100,000
Debt securities, fair value	$ 21,100,000

Fair Value Measurements - Sch_2

Fair Value Measurements - Schedule of Risk-free Interest Rate Based on U.S. Treasury Yield Curve Over Expected Term of Warrants (Details)	Jun. 24, 2019	Dec. 31, 2018
Minimum
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Expected term (in years)	5 years 3 days	5 years 2 months 1 day
Maximum
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Expected term (in years)	5 years 3 months 3 days	7 years
Volatility | Minimum
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Warrants measurement input	57.20	55.56
Volatility | Maximum
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Warrants measurement input	57.24	56.42
Risk-free Interest Rate
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Warrants measurement input	1.75
Risk-free Interest Rate | Minimum
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Warrants measurement input		2.58
Risk-free Interest Rate | Maximum
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Warrants measurement input		3.01

Fair Value Measurements - Summa

Fair Value Measurements - Summary of Changes in Fair Value of Level 3 Financial Instruments (Details) - Level 3 - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Derivative Asset
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Balance	$ 0	$ 0
Initial fair value of derivative asset		623
Elimination as a result of debt extinguishment		(526)
Change in fair value	0	(97)
Balance	0	0
Derivative Liability
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Balance	0	671
Change in fair value	0	(671)
Balance	0	0
Warrant Liability
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Balance	683	292
Reclassification of warrant liability to additional paid in capital on conversion	(2,086)
Change in fair value	1,403	391
Balance	$ 0	$ 683

Borrowings - Additional Informa

Borrowings - Additional Information (Details)

Aug. 14, 2019USD ($)

Mar. 22, 2019USD ($)$ / sharesshares

Sep. 20, 2018USD ($)$ / sharesshares

Aug. 20, 2018USD ($)

May 31, 2018USD ($)

Jun. 29, 2017USD ($)NumberofTime

Jun. 30, 2017USD ($)$ / sharesshares

Sep. 30, 2014USD ($)$ / sharesshares

Dec. 31, 2020USD ($)

Dec. 31, 2019USD ($)shares

Dec. 31, 2018USD ($)

Jun. 30, 2019USD ($)

Jun. 24, 2019shares

Oct. 03, 2014USD ($)

Debt Disclosure [Line Items]

Amounts outstanding under financing arrangements

$ 0

$ 0

Warrant issued to purchase stock | shares

188,643

Conversion of redeemable convertible preferred stock to common stock

89,404,000

Convertible notes, equity component

$ 4,690,000

Loss on debt extinguishment

(1,704,000)

(4,658,000)

Common Stock

Debt Disclosure [Line Items]

Conversion of redeemable convertible preferred stock to common stock

$ 2,000

Fair value of convertible notes, conversion of convertible securities | shares

18,474,703

Convertible Notes

Debt Disclosure [Line Items]

Debt instrument, face value

$ 12,200,000

Debt instrument, interest rate

8.00%

Debt instrument, maturity date

Jun. 28, 2018

Debt instrument, convertible, threshold of proceeds from equity financing, qualified financing

$ 10,000,000

Debt instrument, convertible, conversion price. number of times multiplied on qualified financing | NumberofTime

0.8

Debt instrument, percentage of outstanding principal amount to be repaid in cash in change of control

150.00%

Estimated fair value of compound derivative instrument

$ 500,000

Debt instrument, carrying value, reduction accretion period, based on effective interest method

1 year

Debt instrument, effective interest rate

12.69%

Debt instrument, extended maturity date

Sep. 20, 2018

Conversion of redeemable convertible preferred stock to common stock

$ 13,400,000

Convertible notes, equity component

800,000

Loss on debt extinguishment

$ (800,000)

Debt instrument, carrying value, accretion period, based on effective interest method

1 month

Interest expense, debt

900,000

Series C Redeemable Convertible Preferred Stock

Debt Disclosure [Line Items]

Conversion of redeemable convertible preferred stock to common stock

$ 13,400,000

Fair value of convertible notes, conversion of convertible securities | shares

1,667,997

Debt Instrument, Convertible, Conversion Price | $ / shares

$ 8.052

Series C Redeemable Convertible Preferred Stock | Revolving Loan

Debt Disclosure [Line Items]

Warrant issued to purchase stock | shares

62,096

Warrant exercise price per share | $ / shares

$ 8.052

Term Loan

Debt Disclosure [Line Items]

Estimated fair value of warrants

$ 100,000

Debt Instrument, term

4 years

Interest expense

100,000

Term Loan | Series B Redeemable Convertible Preferred Stock

Debt Disclosure [Line Items]

Warrant exercisable term

10 years

Warrant issued to purchase stock | shares

22,489

Warrant exercise price per share | $ / shares

$ 4.60

Convertible Notes

Debt Disclosure [Line Items]

Debt instrument, extended maturity date

Jun. 28, 2019

Conversion of redeemable convertible preferred stock to common stock

$ 13,100,000

Convertible notes, compound derivative asset

600,000

Convertible notes, equity component

3,900,000

Loss on debt extinguishment

$ (3,300,000)

Debt instrument, carrying value, accretion period, based on effective interest method

1 year 1 month 6 days

Silicon Valley Bank | Term Loan

Debt Disclosure [Line Items]

Line of credit facility, maximum borrowing capacity

$ 3,000,000

Line of credit outstanding

$ 2,400,000

Line of credit facility, frequency of payments

12 interest-only payments, followed by 36 equal monthly installments of principal, plus interest

TriplePoint Capital LLC

Debt Disclosure [Line Items]

Line of credit facility, maximum borrowing capacity

$ 20,000,000

Line of credit outstanding

$ 20,000,000

Line of credit facility, frequency of payments

36 equal monthly payments of principal, plus accrued interest, from April 1, 2020 through March 1, 2023

Estimated fair value of warrants

$ 600,000

Interest expense

$ 1,000,000

Loss on debt extinguishment

$ (1,700,000)

Line of credit facility interest rate

15.23%

Percentage of prepayment fee

1.00%

Percentage of principle payment amount

2.75%

Fees paid to lender

$ 300,000

TriplePoint Capital LLC | Common Stock

Debt Disclosure [Line Items]

Warrant issued to purchase stock | shares

65,502

Warrant exercise price per share | $ / shares

$ 9.16

TriplePoint Capital LLC | Maximum | Option One

Debt Disclosure [Line Items]

Line of credit outstanding

$ 15,000,000

TriplePoint Capital LLC | Minimum | Option Two

Debt Disclosure [Line Items]

Line of credit outstanding

$ 15,000,000

TriplePoint Capital LLC | Prime Rate | Option One

Debt Disclosure [Line Items]

Interest rate, prime rate plus

5.00%

TriplePoint Capital LLC | Prime Rate | Option Two

Debt Disclosure [Line Items]

Interest rate, prime rate plus

6.50%

TriplePoint Capital LLC | Revolving Loan

Debt Disclosure [Line Items]

Line of credit facility, maximum borrowing capacity

$ 10,000,000

Line of credit outstanding

5,000,000

Estimated fair value of warrants

$ 100,000

Debt Instrument, term

1 year 6 months

Interest expense

$ 200,000

$ 900,000

Line of credit facility interest rate

5.50%

19.22%

Line of credit facility maturity date

Dec. 31, 2018

Line of credit facility extended maturity date

Mar. 22, 2019

Repayments of amount outstanding

$ 5,100,000

TriplePoint Capital LLC | Revolving Loan | Prime Rate

Debt Disclosure [Line Items]

Interest rate, prime rate plus

6.75%

TriplePoint Capital LLC | Series C Redeemable Convertible Preferred Stock | Revolving Loan

Debt Disclosure [Line Items]

Warrant issued to purchase stock | shares

62,096

Warrant exercise price per share | $ / shares

$ 8.052

Leases - Additional Information

Leases - Additional Information (Details) $ in Millions	1 Months Ended		12 Months Ended
	Aug. 31, 2019	Feb. 28, 2015ft²	Dec. 31, 2020USD ($)	Dec. 31, 2019USD ($)
Lessee Lease Description [Line Items]
Area of office space | ft²		31,280
Lease expiration date		Nov. 30, 2027
Operating lease, existence of option to extend		true
Operating lease, option to extend			an option to extend the term for a period of three years
Operating lease option to extend term		3 years
Operating lease cost			$ 2.3	$ 1.1
Operating leases, weighted-average remaining lease term			6 years 4 months 24 days
Operating leases, weighted-average discount rate			10.70%
Cash paid for operating lease liabilities			$ 1.7	1.2
Right-of-use assets obtained in exchange for new operating lease liabilities			$ 9.8	$ 2.8
Co-located Data Center Space
Lessee Lease Description [Line Items]
Lease expiration date	Aug. 31, 2022
Operating lease, existence of option to extend	true
Operating lease, option to extend			an option to extend the term for a period of three years
Operating lease option to extend term	3 years

Leases - Schedule of Future Min

Leases - Schedule of Future Minimum Lease Payments (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Leases [Abstract]
2021	$ 2,558
2022	2,194
2023	2,047
2024	2,113
2025	2,182
2026 and thereafter	4,378
Total future minimum lease payments	15,472
Less: imputed interest	(4,486)
Present value of future minimum lease payments	10,986
Less: current portion of operating lease liability	(2,445)	$ (1,361)
Long-term operating lease liabilities	$ 8,541	$ 639

Redeemable Convertible Prefer_4

Redeemable Convertible Preferred Stock - Summary of Redeemable Convertible Preferred Stock Outstanding (Details) $ in Thousands	Dec. 31, 2018USD ($)shares
Temporary Equity [Line Items]
Redeemable convertible preferred stock, Shares Authorized	75,238,150
Redeemable convertible preferred stock, Shares Issued	18,474,742
Redeemable convertible preferred stock, Shares Outstanding	18,474,742
Redeemable convertible preferred stock, Aggregate Liquidation Preference | $	$ 89,784
Redeemable convertible preferred stock, Net Carrying Value | $	$ 89,404
Series A Redeemable Convertible Preferred Stock
Temporary Equity [Line Items]
Redeemable convertible preferred stock, Shares Authorized	31,250,000
Redeemable convertible preferred stock, Shares Issued	7,812,497
Redeemable convertible preferred stock, Shares Outstanding	7,812,497
Redeemable convertible preferred stock, Aggregate Liquidation Preference | $	$ 20,500
Redeemable convertible preferred stock, Net Carrying Value | $	$ 20,261
Series B Redeemable Convertible Preferred Stock
Temporary Equity [Line Items]
Redeemable convertible preferred stock, Shares Authorized	19,288,150
Redeemable convertible preferred stock, Shares Issued	4,799,548
Redeemable convertible preferred stock, Shares Outstanding	4,799,548
Redeemable convertible preferred stock, Aggregate Liquidation Preference | $	$ 22,078
Redeemable convertible preferred stock, Net Carrying Value | $	$ 22,047
Series C Redeemable Convertible Preferred Stock
Temporary Equity [Line Items]
Redeemable convertible preferred stock, Shares Authorized	24,700,000
Redeemable convertible preferred stock, Shares Issued	5,862,697
Redeemable convertible preferred stock, Shares Outstanding	5,862,697
Redeemable convertible preferred stock, Aggregate Liquidation Preference | $	$ 47,206
Redeemable convertible preferred stock, Net Carrying Value | $	$ 47,096

Redeemable Convertible Prefer_5

Redeemable Convertible Preferred Stock - Additional Information (Details) - shares	Jun. 24, 2019	Dec. 31, 2020
Temporary Equity [Line Items]
Reverse stock split description		four-for-one
IPO
Temporary Equity [Line Items]
Redeemable convertible preferred stock, terms of conversion		Immediately prior to the closing of the Company’s IPO, all shares of the Company’s then-outstanding Redeemable Convertible Preferred Stock, as shown in the table above, automatically converted on a one-for-one basis into an aggregate of 18,474,703 shares of common stock.
Fair value of convertible notes, conversion of convertible securities	18,474,703
Number of fractional shares issued	0
Number of issued common shares reduced upon conversion	39
Reverse stock split description		The Reverse Stock Split was effected on a holder-by-holder basis with no fractional shares issued, which resulted in 39 fewer shares of common stock issued as compared to the amounts shown in the above table

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional Information (Details) - USD ($)	3 Months Ended	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unvested shares subject to repurchase rights	0	0	0
Vesting period		4 years
Vesting rate at the end of one year		25.00%
vesting rights description		Options granted to new hires generally vest over a four-year period, with 25% vesting at the end of one year and the remaining vesting monthly thereafter. Options granted as merit awards generally vest monthly over a three- or four-year period
Closing price of common stock	$ 36.61	$ 36.61
Weighted-average grant date fair value of options granted		$ 7.17	$ 8	$ 5.68
Unrecognized stock-based compensation of unvested options	$ 13,300,000	$ 13,300,000
Unrecognized stock-based compensation of unvested options, recognized over weighted-average period		2 years 8 months 12 days
Expected volatility, minimum		61.74%	56.20%	52.19%
Expected volatility, maximum		68.18%	63.08%	56.47%
Risk-free interest rate, minimum		0.36%	1.53%	2.62%
Risk-free interest rate, maximum		1.66%	2.52%	2.88%
Dividend yield		0.00%	0.00%	0.00%
Options Granted as Merit Awards | Tranche One
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting period		3 years
Options Granted as Merit Awards | Tranche Two
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting period		4 years
Restricted Stock Units
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting period		4 years
Closing price of common stock	$ 36.61	$ 36.61
Unrecognized stock-based compensation of unvested options, recognized over weighted-average period		2 years 10 months 24 days
Unrecognized stock-based compensation cost of unvested RSUs	$ 5,900,000	$ 5,900,000
Restricted Stock Units | Tranche One
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting period		3 years
Restricted Stock Units | Tranche Two
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting period		3 years
Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Weighted-average expected life		6 years 4 months 24 days	6 years 10 months 13 days	6 years 4 months 6 days
Minimum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Weighted-average expected life		5 years 6 months	5 years	1 year 6 months
2011 Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Performance-based Options granted	3,389,711	3,389,711	4,474,057
2011 Plan | Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Options granted in years		10 years
2019 Plan | Performance-Based Stock Option
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Options granted in years		10 years
Closing price of common stock	$ 36.61	$ 36.61
Performance-based Options granted	421,000	421,000
Share based compensation arrangement by share based payment equal to or greater than average market capital	$ 1,000,000,000	$ 1,000,000,000
Average market capitalization threshold satisfaction period	30 days	30 days
Share based compensation arrangement by share based payment award description	the Company’s average market capitalization was equal to or greater than $1 billion over a 30 calendar day period and the PSO vested in full.	. The shares subject to the PSO would vest in full if the Company’s average market capitalization is equal to or greater than $1 billion over a 30 calendar day period. Upon a change in control, the vesting of the shares subject to the PSO would accelerate on a pro rata basis based on the price per share in such change in control transaction multiplied by the price per share at such time divided by $1 billion, with up to 100% of the shares eligible for such accelerated vesting
Remaining unrecognized stock-based compensation cost	$ 0	$ 0
Weighted-average expected life		10 years
Risk-free interest rate		1.02%
2019 Plan | Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Options granted in years		10 years
2019 Plan | Maximum | Performance-Based Stock Option
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting rate at the end of one year		100.00%
2019 Plan | Minimum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Percentage of exercise price options granted		100.00%
2019 Employee Stock Purchase Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Percentage of purchase price of common stock		85.00%
Common stock shares purchased		164,164	77,684
Expected volatility, minimum		65.15%	59.06%
Expected volatility, maximum		102.10%	59.91%
Risk-free interest rate		0.10%
Risk-free interest rate, minimum			1.60%
Risk-free interest rate, maximum			2.10%
Dividend yield		0.00%	0.00%
2019 Employee Stock Purchase Plan | Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Percentage of earnings for purchase of common stock at discounted price		15.00%
Weighted-average expected life			6 months
2019 Employee Stock Purchase Plan | Maximum | Employee Stock
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Weighted average grant-date fair values		$ 8.12	$ 5.01
2019 Employee Stock Purchase Plan | Minimum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Weighted-average expected life		6 months	4 months 24 days
2019 Employee Stock Purchase Plan | Minimum | Employee Stock
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Weighted average grant-date fair values		$ 4.29	$ 3.48

Stock-Based Compensation - Summ

Stock-Based Compensation - Summary of Shares of Common Stock Available for Issuance (Details) - shares	Dec. 31, 2020	Dec. 31, 2019
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total number of shares reserved	9,086,875	7,416,094
2011 Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Reserved for issuance upon exercise of options outstanding	3,389,711	4,474,057
2019 Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Reserved for issuance upon exercise or settlement of awards outstanding	2,399,513	377,378
Issuance under 2019 Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares of stock options reserved for issuance	1,977,069	2,392,343
Inducement Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares of stock options reserved for issuance	800,700
Reserved for issuance upon exercise or settlement of awards outstanding	199,300
ESPP
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares of stock options reserved for issuance	320,582	172,316

Stock-Based Compensation - Su_2

Stock-Based Compensation - Summary of Stock Option Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
2011 Plan, 2019 Plan and Inducement Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Outstanding Options, Number of Shares, Beginning Balance	4,731,435	4,110,130	2,884,527
Outstanding Options, Number of Shares, granted	1,357,741	988,913	1,386,464
Outstanding Options, Number of Shares, exercised	(908,691)	(287,932)	(34,426)
Outstanding Options, Number of Shares, cancelled	(232,179)	(79,676)	(126,435)
Outstanding Options, Number of Shares, Ending Balance	4,948,306	4,731,435	4,110,130	2,884,527
Options vested and exercisable, Number of Shares	2,868,867
Outstanding Options, Weighted-Average Exercise Price, Beginning Balance	$ 4.94	$ 3.16	$ 1.92
Outstanding Options, Weighted-Average Exercise Price, granted	12.05	11.81	5.68
Outstanding Options, Weighted-Average Exercise Price, exercised	3.07	2.47	2.80
Outstanding Options, Weighted-Average Exercise Price, cancelled	7.87	6.61	2.96
Outstanding Options, Weighted-Average Exercise Price, Ending Balance	7.10	$ 4.94	$ 3.16	$ 1.92
Options vested and exercisable, Weighted-Average Exercise Price	$ 4.24
Outstanding Options, Weighted-Average Remaining Contractual Term (in years)	6 years 8 months 15 days	6 years 7 months 6 days	6 years 11 months 8 days	6 years 7 months 9 days
Options vested and exercisable, Weighted-Average Remaining Contractual Term (in years)	5 years 2 months 15 days
Outstanding Options, Aggregate Intrinsic Value	$ 146,044	$ 29,730	$ 24,716	$ 5,860
Outstanding Options, Aggregate Intrinsic Value, exercised			$ 96
Options vested and exercisable, Aggregate Intrinsic Value	$ 92,879
2019 Plan | Performance-Based Stock Option
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Outstanding Options, Number of Shares, granted	421,000
Outstanding Options, Number of Shares, Ending Balance	421,000
Options vested and exercisable, Number of Shares	421,000
Outstanding Options, Weighted-Average Exercise Price, granted	$ 5.10
Outstanding Options, Weighted-Average Exercise Price, Ending Balance	5.10
Options vested and exercisable, Weighted-Average Exercise Price	$ 5.10
Outstanding Options, Weighted-Average Remaining Contractual Term (in years)	9 years 2 months 15 days
Options vested and exercisable, Weighted-Average Remaining Contractual Term (in years)	9 years 2 months 15 days
Outstanding Options, Aggregate Intrinsic Value	$ 13,266
Options vested and exercisable, Aggregate Intrinsic Value	$ 13,266

Stock-Based Compensation - Su_3

Stock-Based Compensation - Summary of Weighted-average Assumptions Used in Determination of Fair Value of Service-Based Stock Options (Details) - $ / shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Volatility, minimum	61.74%	56.20%	52.19%
Volatility, maximum	68.18%	63.08%	56.47%
Risk-free interest rate, minimum	0.36%	1.53%	2.62%
Risk-free interest rate, maximum	1.66%	2.52%	2.88%
Dividend yield	0.00%	0.00%	0.00%
2019 Plan | Performance-Based Stock Option
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected term (in years)	10 years
Derived service period (in years)	4 years 6 months 18 days
Volatility	63.60%
Risk-free interest rate	1.02%
Estimated fair value (per share)	$ 3.31
Minimum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected term (in years)	5 years 6 months	5 years	1 year 6 months
Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected term (in years)	6 years 4 months 24 days	6 years 10 months 13 days	6 years 4 months 6 days

Stock-Based Compensation - Su_4

Stock-Based Compensation - Summary of Restricted Stock Units Activity (Details) - Restricted Stock Units - 2019 Plan and Inducement Plan - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unvested Restricted Stock Units, Number of Shares, Beginning Balance	120,000
Unvested Restricted Stock Units, Number of Shares, granted	648,000	120,000
Unvested Restricted Stock Units, Number of Shares, vested	(130,945)
Unvested Restricted Stock Units, Number of Shares, cancelled	(17,837)
Unvested Restricted Stock Units, Number of Shares, Ending Balance	619,218	120,000
Unvested Restricted Stock Units, Weighted-Average Grant Date Fair Value, Beginning Balance	$ 8.86
Estimated fair value (per share)	9.93	$ 8.86
Unvested Restricted Stock Units, Weighted-Average Grant Date Fair Value, vested	7.09
Unvested Restricted Stock Units, Weighted-Average Grant Date Fair Value, cancelled	6.83
Unvested Restricted Stock Units, Weighted-Average Grant Date Fair Value, Ending Balance	$ 10.41	$ 8.86
Unvested Restricted Stock Units, Aggregate Fair Value	$ 1,308
Restricted Stock Units, Aggregate Fair Value, vested	2,991
Unvested Restricted Stock Units, Aggregate Fair Value	$ 22,670	$ 1,308

Stock-Based Compensation - Su_5

Stock-Based Compensation - Summary of Stock-based Compensation Expense by Function (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Stock Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense	$ 8,238	$ 4,858	$ 1,317
Stock Options
Stock Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense	4,729	4,217	1,317
Performance-based Stock Options
Stock Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense	1,392	280
RSUs
Stock Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense	1,401	26
ESPP
Stock Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense	716	335
Costs of revenues
Stock Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense	854	480	177
Research and development
Stock Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense	1,773	903	429
Selling, general, and administrative
Stock Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense	$ 5,611	$ 3,475	$ 711

Redeemable Convertible Prefer_6

Redeemable Convertible Preferred Stock Warrants - Additional Information (Details) - USD ($) $ / shares in Units, $ in Millions	Jun. 30, 2017	Aug. 31, 2020	Jun. 30, 2019	Dec. 31, 2020	Jun. 24, 2019	Sep. 30, 2014
Convertible Preferred Stock Warrants [Line Items]
Warrant issued to purchase stock					188,643
Estimated fair value of convertible preferred stock warrants	$ 0.1
Fair value transferred to additional paid-in capital					$ 2.1
Warrant exercised		62,096	22,489
Common stock issued for exercise of warrant			19,069	40,357
Series B Redeemable Convertible Preferred Stock | Term Loan
Convertible Preferred Stock Warrants [Line Items]
Warrant issued to purchase stock						22,489
Warrant exercise price per share						$ 4.60
Series C Redeemable Convertible Preferred Stock | Revolving Loan
Convertible Preferred Stock Warrants [Line Items]
Warrant issued to purchase stock	62,096
Warrant exercise price per share	$ 8.052

Common Stock Warrants - Additio

Common Stock Warrants - Additional Information (Details) - USD ($) $ / shares in Units, $ in Millions	6 Months Ended	12 Months Ended
	Jun. 30, 2019	Dec. 31, 2020	Jun. 24, 2019	Mar. 22, 2019	Aug. 31, 2011
Common Stock Warrants [Line Items]
Warrant issued to purchase stock			188,643
Common stock issued for exercise of warrant	19,069	40,357
TriplePoint Capital LLC
Common Stock Warrants [Line Items]
Estimated fair value of warrants				$ 0.6
Series A Redeemable Convertible Preferred Stock
Common Stock Warrants [Line Items]
Estimated fair value of warrants					$ 0.1
Common Stock | TriplePoint Capital LLC
Common Stock Warrants [Line Items]
Warrant issued to purchase stock				65,502
Warrant exercise price per share				$ 9.16
Warrants outstanding		0
Common stock issued for exercise of warrant		39,415
Common Stock | Series A Redeemable Convertible Preferred Stock
Common Stock Warrants [Line Items]
Warrant issued to purchase stock					188,643
Warrant exercise price per share					$ 0.04
Warrants outstanding		0

Net Loss per Share Attributab_3

Net Loss per Share Attributable to Common Stockholders - Schedule of Basic and Diluted Net Loss per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Numerator:
Net loss attributable to common stockholders	$ (41,280)	$ (25,084)	$ (19,886)
Denominator:
Weighted-average shares outstanding	34,374,903	18,011,955	3,063,516
Less: weighted-average shares subject to repurchase	0	(485)	(359)
Weighted-average shares outstanding used in computing net loss per share attributable to common stockholders—basic and diluted	34,374,903	18,011,470	3,063,157
Net loss per share, basic and diluted	$ (1.20)	$ (1.39)	$ (6.49)

Net Loss per Share Attributab_4

Net Loss per Share Attributable to Common Stockholders - Schedule of Dilutive Securities Excluded from Computation 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]
Potentially dilutive securities excluded from computation of diluted net loss per share	6,047,326	5,054,438	22,858,362
Redeemable Convertible Preferred Stock
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potentially dilutive securities excluded from computation of diluted net loss per share	0	0	18,474,742
Common Stock Warrants
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potentially dilutive securities excluded from computation of diluted net loss per share	0	127,598	188,643
Series B Preferred Stock Warrant
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potentially dilutive securities excluded from computation of diluted net loss per share	0	0	22,489
Series C Preferred Stock Warrant
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potentially dilutive securities excluded from computation of diluted net loss per share	0	0	62,096
Options To Purchase Common Stock
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potentially dilutive securities excluded from computation of diluted net loss per share	5,369,306	4,731,435	4,110,130
Unvested Restricted Stock Units
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potentially dilutive securities excluded from computation of diluted net loss per share	619,218	120,000	0
Employee Stock Purchase Plan
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potentially dilutive securities excluded from computation of diluted net loss per share	58,802	75,405	0
Unvested Early Exercised Common Stock Options
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potentially dilutive securities excluded from computation of diluted net loss per share	0	0	262

Income Taxes - Schedule of Loss

Income Taxes - Schedule of Loss Before Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Domestic	$ (41,404)	$ (25,111)	$ (19,897)
Foreign	181	36	18
Loss before income taxes	$ (41,223)	$ (25,075)	$ (19,879)

Income Taxes - Schedule of Prov

Income Taxes - Schedule of Provision for Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Current:
State	$ 26	$ 1	$ 2
Foreign	31	8	5
Total current	57	9	7
Provision for income taxes	$ 57	$ 9	$ 7

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Mar. 27, 2020
Income Tax Disclosure [Line Items]
Federal corporate tax rate	21.00%	21.00%	21.00%
Deferred social payroll taxes CARES act				$ 700,000
Increase (Decrease) in valuation allowance on deferred tax assets	$ 16,800,000	$ 7,600,000
Expense, interest or penalties	0	0	$ 0
Accrued, interest or penalties	0	$ 0	$ 0
Federal
Income Tax Disclosure [Line Items]
Net operating loss carryforwards	$ 159,200,000
Net operating loss carryforwards, begins to expire	2031
Tax credit carryforward	$ 4,200,000
Tax credit carryforward, begins to expire	2031
State
Income Tax Disclosure [Line Items]
Net operating loss carryforwards	$ 112,700,000
Net operating loss carryforwards, begins to expire	2031
State | Research
Income Tax Disclosure [Line Items]
Tax credit carryforward	$ 4,300,000

Income Taxes - Summary of Incom

Income Taxes - Summary of Income Tax Provision Related to Continuing Operations Statutory Income Tax Rate (Details)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Expected tax (benefit) at federal statutory rate	(21.00%)	(21.00%)	(21.00%)
Effect of:
State taxes	(10.00%)	(8.00%)	(3.00%)
Change in valuation allowance	38.00%	28.00%	21.00%
Stock-based compensation	(4.00%)	2.00%	1.00%
Research and development credit	(3.00%)	(3.00%)	(3.00%)
Debt extinguishment			4.00%
Other		2.00%	1.00%
Effective tax rate	(0.00%)	(0.00%)	(0.00%)

Income Taxes - Components of De

Income Taxes - Components of Deferred Tax Assets for Federal and State Income Taxes (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Deferred tax assets:
Net operating loss carryforwards	$ 43,221	$ 30,375
Research and development credits	8,455	6,190
Deferred revenue	695	2,154
Accruals	2,260	784
Stock-based compensation	2,157	787
Operating lease liabilities	3,198	574
Other intangibles	366	426
Other	96	114
Total gross deferred tax assets	60,448	41,404
Less: Valuation allowance	(56,846)	(40,000)
Net deferred tax assets	3,602	1,404
Deferred tax liabilities:
Property and equipment	(612)	(875)
Operating lease right-of-use assets	(2,990)	(529)
Net deferred tax liabilities	$ (3,602)	$ (1,404)

Income Taxes - Summary of Unrec

Income Taxes - Summary of Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Beginning balance	$ 1,581	$ 1,192
Gross increase—tax provision in current period	567	389
Ending balance	$ 2,148	$ 1,581

Subsequent Events - Additional

Subsequent Events - Additional Information (Details) - USD ($) $ / shares in Units, $ in Millions	Jan. 29, 2021	Aug. 14, 2020
Subsequent Event
Subsequent Event [Line Items]
Proceeds from Issuance or Sale of Equity	$ 162.3
Follow-On Offering
Subsequent Event [Line Items]
Number of shares issued		6,578,947
Shares issued price per share		$ 19
Proceeds from Issuance or Sale of Equity		$ 117.1
Offering expenses incurred		$ 0.4
Follow-On Offering | Subsequent Event
Subsequent Event [Line Items]
Number of shares issued	3,950,000
Shares issued price per share	$ 38
Proceeds from Issuance or Sale of Equity	$ 141.1
Offering expenses incurred	$ 0.4
Underwriters | Subsequent Event
Subsequent Event [Line Items]
Number of shares issued	592,500
Proceeds from Issuance or Sale of Equity	$ 21.2