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Document And Entity Information - shares	3 Months Ended
Document And Entity Information - shares	Mar. 31, 2020	May 04, 2020
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2020
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q1
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 Common Stock, Shares Outstanding		31,710,477
Entity Current Reporting Status	Yes
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 Quarterly Report	true
Document Transition Report	false
Title of 12(b) Security	Common Stock, par value $0.0001
Trading Symbol	PSNL
Security Exchange Name	NASDAQ

CONDENSED CONSOLIDATED BALANCE SHEETS (unaudited) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Current assets
Cash and cash equivalents	$ 46,694	$ 55,046
Short-term investments	73,339	73,243
Accounts receivable, net	5,508	3,300
Inventory and other deferred costs	6,438	4,606
Prepaid expenses and other current assets	3,437	3,383
Total current assets	135,416	139,578
Property and equipment, net	13,402	14,106
Operating lease right-of-use assets	1,529	1,845
Other long-term assets	1,531	1,762
Total assets	151,878	157,291
Current liabilities
Accounts payable	10,337	7,337
Accrued and other current liabilities	7,375	6,648
Contract liabilities	34,408	35,977
Total current liabilities	52,120	49,962
Other long-term liabilities	556	639
Total liabilities	52,676	50,601
Commitments and Contingencies (Note 12)
Stockholders’ equity
Common stock, $0.0001 par value — 200,000,000 shares authorized; 31,530,443 and 31,243,029 shares issued and outstanding at March 31, 2020 and December 31, 2019, respectively	3	3
Additional paid-in capital	248,854	247,282
Accumulated other comprehensive income (loss)	73	(6)
Accumulated deficit	(149,728)	(140,589)
Total stockholders’ equity	99,202	106,690
Total liabilities and stockholders’ equity	$ 151,878	$ 157,291

CONDENSED CONSOLIDATED BALANCE SHEETS (unaudited) (Parenthetical) - $ / shares	Mar. 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	31,530,443	31,243,029
Common stock, shares, outstanding	31,530,443	31,243,029

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Income Statement [Abstract]
Revenues	$ 19,161	$ 14,075
Costs and expenses
Costs of revenues	15,122	10,091
Research and development	6,390	5,245
Selling, general and administrative	7,274	4,170
Total costs and expenses	28,786	19,506
Loss from operations	(9,625)	(5,431)
Interest income	510	84
Interest expense	(2)	(184)
Other income (expense), net	8	(152)
Loss before income taxes	(9,109)	(5,683)
Provision for income taxes	(30)	(2)
Net loss	$ (9,139)	$ (5,685)
Net loss per share, basic and diluted	$ (0.29)	$ (1.84)
Weighted-average shares outstanding, basic and diluted	31,345,029	3,091,342

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Statement Of Income And Comprehensive Income [Abstract]
Net loss	$ (9,139)	$ (5,685)
Other comprehensive income (loss), net of tax
Foreign currency translation adjustment	(5)	15
Change in unrealized gain on available-for-sale debt securities	84
Comprehensive loss	$ (9,060)	$ (5,670)

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References + Details

CONDENSED CONSOLIDATED STATEMENTS OF REDEEMABLE CONVERTIBLE PREFERRED STOCK AND STOCKHOLDERS EQUITY (DEFICIT) (unaudited) - 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, 2018	$ 89,404					$ 89,404
Redeemable convertible preferred stock, beginning balance, shares at Dec. 31, 2018	18,474,742					18,474,742
Beginning balance at Dec. 31, 2018	$ (106,388)	$ 1	$ 9,131	$ (15)	$ (115,505)
Beginning balance, shares at Dec. 31, 2018		3,085,307
Issuance of common stock warrants	572		572
Proceeds from exercise of stock options	354		354
Proceeds from exercise of stock options, shares		81,009
Stock-based compensation	609		609
Foreign currency translation adjustment	15			15
Net loss	(5,685)				(5,685)
Redeemable convertible preferred stock, ending balance at Mar. 31, 2019						$ 89,404
Redeemable convertible preferred stock, ending balance, shares at Mar. 31, 2019						18,474,742
Ending balance at Mar. 31, 2019	(110,523)	$ 1	10,666		(121,190)
Ending balance, shares at Mar. 31, 2019		3,166,316
Beginning balance at Dec. 31, 2019	106,690	$ 3	247,282	(6)	(140,589)
Beginning balance, shares at Dec. 31, 2019		31,243,029
Proceeds from exercise of stock options	323		323
Proceeds from exercise of stock options, shares		277,415
Restricted stock units released, shares		9,999
Stock-based compensation	1,249		1,249
Foreign currency translation adjustment	(5)			(5)
Unrealized gain on available-for-sale debt securities	84			84
Net loss	(9,139)				(9,139)
Ending balance at Mar. 31, 2020	$ 99,202	$ 3	$ 248,854	$ 73	$ (149,728)
Ending balance, shares at Mar. 31, 2020		31,530,443

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Cash flows from operating activities:
Net loss	$ (9,139)	$ (5,685)
Adjustments to reconcile net loss to net cash (used in) provided by operating activities
Depreciation and amortization	1,396	1,047
Noncash operating lease cost	315	214
Stock-based compensation expense	1,249	609
Change in fair value of convertible preferred stock warrant liability		134
Accretion of noncash interest and debt reduction		22
Other	(64)	13
Changes in operating assets and liabilities
Accounts receivable	(2,208)	1,346
Inventory and other deferred costs	(1,832)	548
Prepaid expenses and other current assets	178	(108)
Accounts payable	2,385	(820)
Accrued and other current liabilities	729	1,587
Contract liabilities	(1,569)	1,419
Other long-term liabilities	(83)	(260)
Net cash (used in) provided by operating activities	(8,643)	66
Cash flows from investing activities:
Purchases of available-for-sale debt securities	(27,242)
Proceeds from maturities of available-for-sale debt securities	27,283
Purchases of property and equipment	(76)	(960)
Net cash used in investing activities	(35)	(960)
Cash flows from financing activities:
Payments of costs related to initial public offering		(477)
Proceeds from borrowings		20,000
Payments of borrowing costs		(490)
Repayments under borrowing arrangements		(5,000)
Proceeds from exercise of stock options	323	353
Net cash provided by financing activities	323	14,386
Effect of exchange rates on cash flows and cash equivalents	3	1
Net change in cash and cash equivalents	(8,352)	13,493
Cash and cash equivalents, beginning of period	55,046	19,744
Cash and cash equivalents, end of period	$ 46,694	$ 33,237

Company and Nature of Business

3 Months Ended

Mar. 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. 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. The Company operates and manages its business as one reportable operating segment, which is the sale of sequencing and data analysis services.

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 Accounting Policies

3 Months Ended

Mar. 31, 2020

Accounting Policies [Abstract]

Summary of Significant Accounting Policies

Note 2. Summary of Significant Accounting Policies

Basis of Presentation

The accompanying unaudited condensed 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 interim reporting. Certain information and note disclosures normally included in the financial statements prepared in accordance with U.S. GAAP have been condensed or omitted pursuant to such rules and regulations. As such, the information included in this Quarterly Report on Form 10-Q should be read in conjunction with the consolidated financial statements and accompanying notes included in the Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2019.

The condensed consolidated financial statements include the accounts of Personalis, Inc. and its wholly owned subsidiary, Personalis (UK) Ltd. All intercompany balances and transactions have been eliminated in consolidation.

The accompanying condensed consolidated financial statements reflect all normal recurring adjustments that are necessary to present fairly the results for the interim periods presented. Interim results are not necessarily indicative of the results for the full year ending December 31, 2020.

Use of Estimates

The preparation of condensed 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 condensed 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 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 condensed consolidated financial position and results of operations.

Initial Public Offering

On June 20, 2019, the Company completed an 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, all of which were paid by December 31, 2019.

A warrant to purchase 188,643 shares of our common stock was exercised prior to completion of the Company’s 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, of which 62,096 are still outstanding as of March 31, 2020 (see Note 10).

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‑grade debt instruments and has policy limits for the amount it can invest in any one type of security, except for securities issued or guaranteed by the U.S. government. The goals of the Company’s investment policy are as follows: preservation of principal; liquidity of investments sufficient to meet cash flow requirements; avoidance of inappropriate concentration and credit risk; competitive after‑tax rate of returns; and fiduciary control of cash and investments. Under its investment policy, the Company limits the amounts invested in such securities by credit rating, maturity, investment type, and issuer. As a result, management believes that these financial instruments do not expose the Company to any significant concentrations of credit risk.

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 March 31, 2020 and December 31, 2019. During the three months ended March 31, 2020 and 2019, the Company had no bad debt expense.

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 (unaudited)		Accounts Receivable
	Three Months Ended March 31,		March 31, 2020	December 31, 2019
	2020	2019	(unaudited)
VA MVP	77%	59%	36%	19%
Pfizer Inc.	*	17%	12%	23%
Indivumed GmbH	*	*	22%	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 condensed consolidated statements of operations.

Costs of Revenues

The Company’s costs of revenues primarily consist of production materials, personnel costs (e.g., salaries, bonuses, benefit, and stock-based compensation), cost of expensed equipment, consumables and laboratory supplies, information technology (“IT”) and facility costs, and depreciation and service maintenance contracts on capitalized equipment.

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.

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 stock options 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 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 value 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 asset 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.

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.

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 March 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” and the noncurrent portion included in “Other long-term 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 ASU 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 2019, the FASB delayed the effective date for Topic 326 as applicable to 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

3 Months Ended

Mar. 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):

	Three Months Ended March 31,
	2020		2019
VA MVP	$	14,756	$	8,343
All other customers		4,405		5,732
Total	$	19,161	$	14,075

Revenues from countries outside of the United States, based on the billing addresses of customers, represented approximately 9% and 2% of the Company’s revenues for the three months ended March 31, 2020 and 2019, respectively.

Contract Assets and Liabilities

The Company had no contract assets as of March 31, 2020 and 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 condensed consolidated balance sheets.

The balance of contract liabilities was $34.4 million and $36.0 million as of March 31, 2020 and December 31, 2019, respectively. Revenues recognized for the three months ended March 31, 2020 and 2019 that were included in the contract liability balance at the beginning of each reporting period were $10.7 million and $7.8 million, respectively.

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 $54.0 million as of March 31, 2020, which we expect to recognize as revenues over the next 12 months.

Balance Sheet Details

3 Months Ended

Mar. 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):

	March 31,		December 31,
	2020		2019
Raw materials	$	3,919	$	1,424
Other deferred costs		2,519		3,182
Total inventory and other deferred costs	$	6,438	$	4,606

Property and equipment. Depreciation and amortization expense for the three months ended March 31, 2020 and 2019 was $1.4 million and $1.0 million, respectively. Accumulated depreciation and amortization was $10.2 million and $9.1 million as of March 31, 2020 and December 31, 2019, respectively.

Accrued and other current liabilities consist of the following (in thousands):

	March 31,		December 31,
	2020		2019
Accrued compensation	$	5,399	$	4,147
Operating lease liabilities		1,107		1,361
Accrued taxes		57		210
Accrued liabilities		268		689
Other current liabilities		544		241
Total accrued and other current liabilities	$	7,375	$	6,648

Fair Value Measurements

3 Months Ended

Mar. 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 March 31, 2020 and December 31, 2019 (in thousands):

	As of March 31, 2020
	Adjusted Cost		Unrealized Gains		Unrealized Losses			Fair Value		Fair Value Level
Assets
Cash and cash equivalents:
Cash	$	4,015	$	—	$	—		$	4,015
Money market funds		25,042		—		—			25,042	Level 1
Commercial paper		17,648		—		(11	)		17,637	Level 2
Total cash and cash equivalents		46,705		—		(11	)		46,694
Short-term investments:
Commercial paper		17,645		4		(13	)		17,636	Level 2
U.S. government securities		2,003		5		—			2,008	Level 2
Corporate debt securities		12,893		4		(3	)		12,894	Level 2
U.S. agency securities		38,498		105		—			38,603	Level 2
Asset-backed securities		2,199		—		(1	)		2,198	Level 2
Total short-term investments		73,238		118		(17	)		73,339
Total assets measured at fair value	$	119,943	$	118	$	(28	)	$	120,033

	As of 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. The Company began investing in marketable debt securities during the third quarter of 2019 and, therefore, 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 March 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 March 31, 2020 have maturities due in one year or less, except for debt securities with an aggregate cost basis and fair value of $13.2 million that have maturities ranging from 13 to 18 months.

The Black-Scholes option-pricing model was used to estimate the fair value of the redeemable convertible preferred stock warrants at the date of issuance and at each subsequent consolidated balance sheet date. The fair value of the redeemable convertible preferred stock warrants was also estimated at the time of conversion to common stock warrants (see Note 10). Under this option-pricing model, redeemable 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 redeemable 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.

		Three Months Ended
		March 31, 2019
Expected term (in years)		5.50 - 7.00
Volatility		56.89% - 57.24%
Risk-free interest rate		2.25% - 2.31%
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
Balance — December 31, 2018	$	683
Change in fair value		134
Balance — March 31, 2019	$	817

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References + Details

Borrowings

3 Months Ended

Mar. 31, 2020

Debt Disclosure [Abstract]

Borrowings

Note 6. Borrowings

There were no amounts outstanding under financing arrangements as of March 31, 2020 or December 31, 2019.

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 current 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 exercisable for seven years from June 28, 2017 (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. The Revolving Loan interest expense for the three months ended March 31, 2019 was $0.2 million. 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 rate plus 5.00% for borrowings up to $15.0 million and the prime rate plus 6.50% for borrowing 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 voluntarily 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 exercisable for seven years from March 22, 2019. 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 three months ended March 31, 2019 was not material. On August 14, 2019 the Company paid off the Growth Capital Loan in its entirety.

Leases

3 Months Ended

Mar. 31, 2020

Leases [Abstract]

Leases

Note 7. Leases

Operating Lease Obligations

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 office space. The lease expires on November 30, 2020 and includes an option to extend the term for a period of three years immediately following the expiration of the term with rent payments equal to then current fair market rental for the space.

In August 2019, the Company entered into a noncancelable operating lease for a co-located data center space. The lease expires on September 1, 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 amounts of lease liability related to the laboratory and office space lease using a discount rate of 8.0%. With respect to the lease for co-located data center space, the Company determined the amounts of lease liability using a discount rate of 6.6%, and the Company recognized a $1.1 million operating lease right-of-use asset and lease liability on the lease commencement date in September 2019. Both discount rates represented the Company’s incremental borrowing rates. The Company determined that the optional renewal periods for both leases were not reasonably certain to be exercised as of the lease commencement dates. As a result, the optional renewal periods were not recognized as part of the right-of-use assets or lease liabilities.

Operating lease cost for the three months ended March 31, 2020 and 2019 was $0.3 million and $0.2 million, respectively. Cash paid for operating lease liabilities, included in cash flow from operating activities in the condensed consolidated statement of cash flows was $0.4 million and $0.3 million for the three months ended March 31, 2020 and 2019, respectively. As of March 31, 2020, the weighted average remaining lease term for the operating leases was 1.6 years and the weighted average incremental borrowing rate was 7.2%.

Future minimum lease payments at March 31, 2020 under noncancelable operating leases were as follows (in thousands):

	Amount
2020 (remaining nine months)	$	1,039
2021		403
2022		319
Total future minimum lease payments		1,761
Less: imputed interest		(98	)
Present value of future minimum lease payments		1,663
Less: current portion of operating lease liability		(1,107	)
Operating lease liabilities - noncurrent	$	556

In April 2020, the Company executed an amendment to the lease for its laboratory and office space with the lessor to provide for a seven-year extension (the “Lease Extension”). The lease term was extended from December 2020 through November 2027. Future minimum lease payments under the lease extension are $14.8 million and commence on December 1, 2020. The Lease Extension includes an option to extend the term for a period of three years immediately following the expiration of the term with rent payments equal to then current fair market rental for the space.

In April 2020, the lease for co-located data center space was modified to increase the data center space available for the Company’s use by approximately 57% for the remainder of the lease term. Minimum lease payments increased $0.5 million for the remainder of the lease term.

Redeemable Convertible Preferred Stock

3 Months Ended

Mar. 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 Company’s June 2019 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

3 Months Ended

Mar. 31, 2020

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Stock-Based Compensation

Note 9. Stock-Based Compensation

2011 Equity Incentive Plan and 2019 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. The exercise price of an ISO granted to a 10% stockholder was not less than 110% of the estimated fair value of the shares on the date of grant, as determined by the board of directors. Options granted to new hires generally vested 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 vested monthly over a four-year period.

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 are 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 lapse. There were zero unvested shares subject to the Company’s repurchase rights as of March 31, 2020 and December 31, 2019.

The Company’s Board adopted and the Company’s stockholders approved the Company’s 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 our common stock on the date of grant. Options under the 2019 Plan may be granted for periods of up to 10 years.

Shares of common stock available for issuance under the 2011 Plan and 2019 Plan at March 31, 2020 and December 31, 2019 were as follows:

	March 31,		December 31,
	2020		2019
Reserved for issuance upon exercise of options outstanding under the 2011 Plan		4,173,216		4,474,057
Reserved for issuance upon exercise of options outstanding under the 2019 Plan		1,283,674		257,378
Reserved for issuance upon settlement of RSUs under the 2019 Plan		407,101		120,000
Reserved and available for issuance under the 2019 Plan⁽¹⁾		2,654,524		2,392,343
Total number of shares reserved		8,518,515		7,243,778
⁽¹⁾ Includes share increase added January 1, 2020 pursuant to the “evergreen” provision in the amount of 1,562,151 shares

Stock Option Activity (excluding performance-based stock options)

A summary of the Company’s stock option activity, excluding performance-based stock options, under the 2011 Plan and 2019 Plan for the three months ended March 31, 2020 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, 2019		4,731,435		$	4.94		6.60	$	29,730
Options granted		616,796			6.07
Options exercised		(277,415	)		1.16
Options cancelled		(34,926	)		10.22
Balance—March 31, 2020		5,035,890		$	5.25		6.93	$	17,953
Options vested and exercisable as of March 31, 2020		2,785,380		$	3.46		5.28	$	13,745

The aggregate intrinsic value of unexercised stock options is calculated as the difference between the closing price of the Company’s common stock of $8.07 on March 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 $3.46 and $7.76 per share for the three months ended March 31, 2020 and 2019, respectively. As of March 31, 2020, the unrecognized stock-based compensation cost of unvested options was $10.5 million, which is expected to be recognized over a weighted-average period of 2.7 years.

Valuation of Stock Options (excluding performance-based stock options)

The Company estimated the fair value of stock options 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 service-based stock options was estimated using the following weighted-average assumptions:

	Three Months Ended March 31,
	2020	2019
Expected term (in years)	5.77 - 6.08	6.87
Volatility	61.74 - 64.13%	56.20%
Risk-free interest rate	0.58 - 1.66%	2.49 - 2.52%
Dividend yield	–%	–%

Performance-Based Stock Option Activity

Pursuant to the 2019 Plan, the Company granted in March 2020 a performance-based stock option (“PSO”) to the Company’s Chief Executive Officer. The PSO awarded is subject to the Chief Executive Officer’s continued service to the Company through the date of vesting and if the performance metrics are not met within the contractual term, the PSO will be canceled. The shares subject to the PSO will vest in full if a market price condition is met. Upon a change in control, the vesting of the shares subject to the PSO will accelerate on a pro rata basis based on the price per share in such change in control transaction relative to the market price condition, 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 three months ended March 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—March 31, 2020		421,000	$	5.10		9.96	$	1,250
Options vested and exercisable as of March 31, 2020		—	$	—		—	$	—

The aggregate intrinsic value of unexercised stock options is calculated as the difference between the closing price of the Company’s common stock of $8.07 on March 31, 2020 and the exercise price of the underlying stock options. As of March 31, 2020, the unrecognized stock-based compensation cost of unvested performance-based options was $1.4 million, which is expected to be recognized over a period of 4.5 years.

Valuation of Performance-Based Stock Options

The assumptions used in calculating the estimated values of the PSO were based upon Monte Carlo Model Assumptions and estimates as follows:

	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 for the three months ended March 31, 2020 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, 2019		120,000		$	8.86	$	1,308
RSUs granted		297,100			4.88
RSUs vested		(9,999	)		8.86		98
RSUs cancelled		—			—
Balance—March 31, 2020		407,101		$	5.95	$	3,285

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 yearly over a four-year period. RSUs granted as merit awards generally vest 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 $8.07 on March 31, 2020.

Amortization of stock-based compensation expense related to RSUs in the first three months of 2020 was $0.1 million. As of March 31, 2020, the unrecognized stock-based compensation cost of unvested RSUs was $2.4 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 us to the taxing authorities.

2019 Employee Stock Purchase Plan

In May 2019, the board of directors adopted the 2019 Employee Stock Purchase Plan (the “ESPP”), which was approved by the Company’s stockholders in June 2019. The number of shares available for issuance under the ESPP as of March 31, 2020 is 484,746, which includes shares added January 1, 2020 pursuant to the “evergreen” provision in the amount of 312,430 shares.

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. Except for the initial offering period, the ESPP provides for separate six-month offering periods beginning on May 1 and November 1 of each year. The initial offering period ran from June 20, 2019 through October 31, 2019.

During the three months ended March 31, 2020, no shares of common stock were purchased under the ESPP. The total compensation expense related to the ESPP for the three months ended March 31, 2020 was $0.1 million. The following assumptions were used to calculate the stock-based compensation for each stock purchase right granted under the ESPP: a weighted-average expected life of 0.5 years, expected volatility of 59.9%, a risk-free interest rate of 1.6%, and a zero dividend yield.

Stock-Based Compensation Expense

The following is a summary of stock-based compensation expense by function (in thousands):

	Three Months Ended March 31,
	2020		2019
Costs of revenues	$	143	$	85
Research and development		259		164
Selling, general and administrative		847		360
Total stock-based compensation expense	$	1,249	$	609

Redeemable Convertible Preferred Stock Warrants

3 Months Ended

Mar. 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 a loan, 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, subject to certain adjustments, such as any stock splits, stock dividends, recapitalizations, reclassifications, combinations, or similar transactions. The remaining term of the Series C convertible preferred stock warrant is seven years from June 28, 2017.

The estimated fair value of the Series C convertible preferred stock warrant on the date of issuance of $0.1 million was recorded as a debt reduction. As of the issuance date, the fair value of the Series C convertible preferred stock warrant was calculated using the Black-Scholes option-pricing model and was based on a contractual term of seven years, a risk-free interest rate of 1.97%, expected volatility of 64.33%, and 0% expected dividend yield.

At initial recognition, the convertible preferred stock warrants were recorded at their estimated fair values and were subject to remeasurement at each consolidated balance sheet date, with changes in fair value recognized as a component of net income. As of December 31, 2018, the fair values of the convertible preferred stock warrants were calculated to be $0.7 million.

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 common stock warrant for 22,489 shares was exercised. As a result, the Company issued 19,069 shares of common stock as the contract allows a net share settlement. Separately, the common stock warrant issued in June 2017 for 62,096 shares was still outstanding as of March 31, 2020.

Common Stock Warrants

3 Months Ended

Mar. 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 exercisable for seven years from March 22, 2019. 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 is still outstanding as of March 31, 2020.

Commitments and Contingencies

3 Months Ended

Mar. 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 condensed 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 March 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 to Common Stockholders

3 Months Ended

Mar. 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 the three months ended March 31, 2020 and 2019, 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):

	Three Months Ended March 31,
	2020			2019
Numerator:
Net loss attributable to common stockholders	$	(9,139	)	$	(5,685	)
Denominator:
Weighted-average shares outstanding		31,345,029			3,091,504
Less: weighted-average shares subject to repurchase		—			(162	)
Weighted-average shares outstanding used in computing net loss per share attributable to common stockholders — basic and diluted		31,345,029			3,091,342
Net loss per share attributable to common stockholders — basic and diluted	$	(0.29	)	$	(1.84	)

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:

	Three Months Ended March 31,
	2020		2019
Redeemable convertible preferred stock		—		18,474,742
Common stock warrants		127,598		254,145
Series B preferred stock warrant		—		22,489
Series C preferred stock warrant		—		62,096
Options to purchase common stock		5,456,890		4,381,884
Unvested restricted stock units		407,101		—
Employee stock purchase plan		70,420		—
Unvested early exercised common stock options		—		1,016
Total		6,062,009		23,196,372

Summary of Significant Accounting Policies (Policies)

3 Months Ended

Mar. 31, 2020

Accounting Policies [Abstract]

Basis of Presentation

Use of Estimates

Initial Public Offering

Concentration of Credit Risk and Other Risks and Uncertainties

	Revenues (unaudited)		Accounts Receivable
	Three Months Ended March 31,		March 31, 2020	December 31, 2019
	2020	2019	(unaudited)
VA MVP	77%	59%	36%	19%
Pfizer Inc.	*	17%	12%	23%
Indivumed GmbH	*	*	22%	30%

*	Less than 10% of revenues or accounts receivable

Revenue Recognition

Practical Expedients and Exemptions

Costs of Revenues

Stock-Based Compensation

Inputs used in Black-Scholes option-pricing models to measure fair value of options are summarized as follows:

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.

Net Loss per Share Attributable to Common Stockholders

Cash and Cash Equivalents

Short-term Investments

Fair Value Measurements

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.

•

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 asset 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.

This hierarchy requires the Company to use observable market data, when available, and to minimize the use of unobservable inputs when determining fair value.

Inventory and Other Deferred Costs

Leases

Recent Accounting Pronouncements

New Accounting Pronouncements Not Yet Adopted

JOBS Act Accounting Election

Summary of Significant Accounting Policies (Tables)

3 Months Ended

Mar. 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 (unaudited)		Accounts Receivable
	Three Months Ended March 31,		March 31, 2020	December 31, 2019
	2020	2019	(unaudited)
VA MVP	77%	59%	36%	19%
Pfizer Inc.	*	17%	12%	23%
Indivumed GmbH	*	*	22%	30%

*	Less than 10% of revenues or accounts receivable

Revenues (Tables)

3 Months Ended

Mar. 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):

	Three Months Ended March 31,
	2020		2019
VA MVP	$	14,756	$	8,343
All other customers		4,405		5,732
Total	$	19,161	$	14,075

Balance Sheet Details (Tables)

3 Months Ended

Mar. 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):

	March 31,		December 31,
	2020		2019
Raw materials	$	3,919	$	1,424
Other deferred costs		2,519		3,182
Total inventory and other deferred costs	$	6,438	$	4,606

Schedule of Accrued and Other Current Liabilities

Accrued and other current liabilities consist of the following (in thousands):

	March 31,		December 31,
	2020		2019
Accrued compensation	$	5,399	$	4,147
Operating lease liabilities		1,107		1,361
Accrued taxes		57		210
Accrued liabilities		268		689
Other current liabilities		544		241
Total accrued and other current liabilities	$	7,375	$	6,648

Fair Value Measurements (Tables)

3 Months Ended

Mar. 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

	As of March 31, 2020
	Adjusted Cost		Unrealized Gains		Unrealized Losses			Fair Value		Fair Value Level
Assets
Cash and cash equivalents:
Cash	$	4,015	$	—	$	—		$	4,015
Money market funds		25,042		—		—			25,042	Level 1
Commercial paper		17,648		—		(11	)		17,637	Level 2
Total cash and cash equivalents		46,705		—		(11	)		46,694
Short-term investments:
Commercial paper		17,645		4		(13	)		17,636	Level 2
U.S. government securities		2,003		5		—			2,008	Level 2
Corporate debt securities		12,893		4		(3	)		12,894	Level 2
U.S. agency securities		38,498		105		—			38,603	Level 2
Asset-backed securities		2,199		—		(1	)		2,198	Level 2
Total short-term investments		73,238		118		(17	)		73,339
Total assets measured at fair value	$	119,943	$	118	$	(28	)	$	120,033

	As of 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.

		Three Months Ended
		March 31, 2019
Expected term (in years)		5.50 - 7.00
Volatility		56.89% - 57.24%
Risk-free interest rate		2.25% - 2.31%
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
Balance — December 31, 2018	$	683
Change in fair value		134
Balance — March 31, 2019	$	817

Leases (Tables)

3 Months Ended

Mar. 31, 2020

Leases [Abstract]

Schedule of Future Minimum Lease Payments

Future minimum lease payments at March 31, 2020 under noncancelable operating leases were as follows (in thousands):

	Amount
2020 (remaining nine months)	$	1,039
2021		403
2022		319
Total future minimum lease payments		1,761
Less: imputed interest		(98	)
Present value of future minimum lease payments		1,663
Less: current portion of operating lease liability		(1,107	)
Operating lease liabilities - noncurrent	$	556

Redeemable Convertible Preferred Stock (Tables)

3 Months Ended

Mar. 31, 2020

Temporary Equity Disclosure [Abstract]

Summary of Redeemable Convertible Preferred Stock Outstanding

	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 (Tables)

3 Months Ended

Mar. 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 2011 Plan and 2019 Plan at March 31, 2020 and December 31, 2019 were as follows:

	March 31,		December 31,
	2020		2019
Reserved for issuance upon exercise of options outstanding under the 2011 Plan		4,173,216		4,474,057
Reserved for issuance upon exercise of options outstanding under the 2019 Plan		1,283,674		257,378
Reserved for issuance upon settlement of RSUs under the 2019 Plan		407,101		120,000
Reserved and available for issuance under the 2019 Plan⁽¹⁾		2,654,524		2,392,343
Total number of shares reserved		8,518,515		7,243,778
⁽¹⁾ Includes share increase added January 1, 2020 pursuant to the “evergreen” provision in the amount of 1,562,151 shares

Summary of Stock Option Activity

A summary of the Company’s stock option activity, excluding performance-based stock options, under the 2011 Plan and 2019 Plan for the three months ended March 31, 2020 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, 2019		4,731,435		$	4.94		6.60	$	29,730
Options granted		616,796			6.07
Options exercised		(277,415	)		1.16
Options cancelled		(34,926	)		10.22
Balance—March 31, 2020		5,035,890		$	5.25		6.93	$	17,953
Options vested and exercisable as of March 31, 2020		2,785,380		$	3.46		5.28	$	13,745

Summary of Weighted-average Assumptions Used in Determination of Fair Value of Stock Options

The fair value of service-based stock options was estimated using the following weighted-average assumptions:

	Three Months Ended March 31,
	2020	2019
Expected term (in years)	5.77 - 6.08	6.87
Volatility	61.74 - 64.13%	56.20%
Risk-free interest rate	0.58 - 1.66%	2.49 - 2.52%
Dividend yield	–%	–%

Summary of Restricted Stock Units Activity

A summary of the Company’s RSU activity under the 2019 Plan for the three months ended March 31, 2020 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, 2019		120,000		$	8.86	$	1,308
RSUs granted		297,100			4.88
RSUs vested		(9,999	)		8.86		98
RSUs cancelled		—			—
Balance—March 31, 2020		407,101		$	5.95	$	3,285

Stock Based Compensation Expense by Function

The following is a summary of stock-based compensation expense by function (in thousands):

	Three Months Ended March 31,
	2020		2019
Costs of revenues	$	143	$	85
Research and development		259		164
Selling, general and administrative		847		360
Total stock-based compensation expense	$	1,249	$	609

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 three months ended March 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—March 31, 2020		421,000	$	5.10		9.96	$	1,250
Options vested and exercisable as of March 31, 2020		—	$	—		—	$	—

Summary of Weighted-average Assumptions Used in Determination of Fair Value of Stock Options

The assumptions used in calculating the estimated values of the PSO were based upon Monte Carlo Model Assumptions and estimates as follows:

	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 Attributable to Common Stockholders (Tables)

3 Months Ended

Mar. 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):

	Three Months Ended March 31,
	2020			2019
Numerator:
Net loss attributable to common stockholders	$	(9,139	)	$	(5,685	)
Denominator:
Weighted-average shares outstanding		31,345,029			3,091,504
Less: weighted-average shares subject to repurchase		—			(162	)
Weighted-average shares outstanding used in computing net loss per share attributable to common stockholders — basic and diluted		31,345,029			3,091,342
Net loss per share attributable to common stockholders — basic and diluted	$	(0.29	)	$	(1.84	)

Schedule of Dilutive Securities Excluded from Computation of Diluted Net Loss per Share

	Three Months Ended March 31,
	2020		2019
Redeemable convertible preferred stock		—		18,474,742
Common stock warrants		127,598		254,145
Series B preferred stock warrant		—		22,489
Series C preferred stock warrant		—		62,096
Options to purchase common stock		5,456,890		4,381,884
Unvested restricted stock units		407,101		—
Employee stock purchase plan		70,420		—
Unvested early exercised common stock options		—		1,016
Total		6,062,009		23,196,372

Company and Nature of Business - Additional Information (Details)	3 Months Ended
	Mar. 31, 2020 Segment
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Number of reportable segments	1

Summary of Significant Accounting Policies - Additional Information (Details) - USD ($)		3 Months Ended
	Jun. 20, 2019	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Summary Of Significant Accounting Policies [Line Items]
Offering expenses	$ 4,200,000
Conversion from convertible warrants	188,643
Allowance for doubtful accounts		$ 100,000		$ 100,000
Bad debt expense		$ 0	$ 0
Dividend yield		0.00%	0.00%
Dividends		$ 0
Minimum \| ASU 2014-09
Summary Of Significant Accounting Policies [Line Items]
Standard payment terms		90 days
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
Common Stock
Summary Of Significant Accounting Policies [Line Items]
Warrant outstanding		62,096
IPO
Summary Of Significant Accounting Policies [Line Items]
Number of shares issued	9,109,725
Shares issued price per share	$ 17.00
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 preferred stock	18,474,703
IPO \| Common Stock
Summary Of Significant Accounting Policies [Line Items]
Warrant outstanding		62,096
IPO \| Convertible Preferred Stock
Summary Of Significant Accounting Policies [Line Items]
Conversion from convertible warrants to purchase common stock	84,585

Summary of Significant Accounting Policies - Schedule of Percentage of Revenues and Accounts Receivables from Customers (Details) - Customer	3 Months Ended		12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
VA MVP \| Revenues
Summary Of Significant Accounting Policies [Line Items]
Concentration risk percentage	77.00%	59.00%
VA MVP \| Accounts Receivable
Summary Of Significant Accounting Policies [Line Items]
Concentration risk percentage	36.00%		19.00%
Pfizer Inc. \| Revenues
Summary Of Significant Accounting Policies [Line Items]
Concentration risk percentage		17.00%
Pfizer Inc. \| Accounts Receivable
Summary Of Significant Accounting Policies [Line Items]
Concentration risk percentage	12.00%		23.00%
Indivumed GmbH \| Accounts Receivable
Summary Of Significant Accounting Policies [Line Items]
Concentration risk percentage	22.00%		30.00%

Summary of Significant Accounting Policies - Schedule of Percentage of Revenues and Accounts Receivables from Customers (Parenthetical) (Details)	3 Months Ended
	Mar. 31, 2020
Accounts Receivable \| Minimum \| Customer
Summary Of Significant Accounting Policies [Line Items]
Concentration risk percentage	10.00%

Revenues - Schedule of Revenues Disaggregated by Customer Type (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Disaggregation Of Revenue [Line Items]
Revenues	$ 19,161	$ 14,075
VA MVP
Disaggregation Of Revenue [Line Items]
Revenues	14,756	8,343
All Other Customers
Disaggregation Of Revenue [Line Items]
Revenues	$ 4,405	$ 5,732

Revenues - Additional Information (Details) - USD ($)	3 Months Ended
Revenues - Additional Information (Details) - USD ($)	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Disaggregation Of Revenue [Line Items]
Contract assets	$ 0		$ 0
Contract liabilities	34,400,000		$ 36,000,000
Contract liability, revenue recognized	$ 10,700,000	$ 7,800,000
Customer Concentration Risk \| Revenues \| Maximum \| Outside of United States
Disaggregation Of Revenue [Line Items]
Revenue	9.00%	2.00%

Revenues - Additional Information (Details 1) - Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2020-04-01 $ in Millions	Mar. 31, 2020 USD ($)
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Remaining performance obligation, amount	$ 54.0
Remaining performance obligation, expected time of satisfaction	12 months

Balance Sheet Details - Schedule of Inventory and Other Deferred Costs (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Inventory And Other Deferred Costs [Abstract]
Raw materials	$ 3,919	$ 1,424
Other deferred costs	2,519	3,182
Total inventory and other deferred costs	$ 6,438	$ 4,606

Balance Sheet Details - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Income Statement [Abstract]
Depreciation and amortization expense	$ 1,396	$ 1,047
Accumulated depreciation and amortization	$ 10,200		$ 9,100

Balance Sheet Details - Schedule of Accrued and Other Current Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Payables And Accruals [Abstract]
Accrued compensation	$ 5,399	$ 4,147
Operating lease liabilities	1,107	1,361
Accrued taxes	57	210
Accrued liabilities	268	689
Other current liabilities	544	241
Total accrued and other current liabilities	$ 7,375	$ 6,648

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	Mar. 31, 2020	Dec. 31, 2019
Assets
Cash and cash equivalents, Adjusted Cost	$ 46,694	$ 55,046
Fair Value Measurements Recurring
Assets
Cash and cash equivalents, Adjusted Cost	46,705	55,047
Cash and cash equivalents, Unrealized Losses	(11)	(1)
Cash and cash equivalents, Fair Value	46,694	55,046
Assets, Adjusted Cost	119,943	128,283
Assets, Unrealized Gains	118	21
Assets, Unrealized Losses	(28)	(15)
Assets, Fair Value	120,033	128,289
Fair Value Measurements Recurring \| Short-term Investments
Assets
Investments, Adjusted Cost	73,238	73,236
Investments, Unrealized Gains	118	21
Investments, Unrealized Losses	(17)	(14)
Investments, Fair Value	73,339	73,243
Fair Value Measurements Recurring \| Cash
Assets
Cash and cash equivalents, Adjusted Cost	4,015	1,271
Cash and cash equivalents, Fair Value	4,015	1,271
Fair Value Measurements Recurring \| Level 1 \| Money Market Funds
Assets
Cash and cash equivalents, Adjusted Cost	25,042	12,495
Cash and cash equivalents, Fair Value	25,042	12,495
Fair Value Measurements Recurring \| Level 2 \| Commercial Paper
Assets
Cash and cash equivalents, Adjusted Cost	17,648	41,281
Cash and cash equivalents, Unrealized Losses	(11)	(1)
Cash and cash equivalents, Fair Value	17,637	41,280
Fair Value Measurements Recurring \| Level 2 \| Commercial Paper \| Short-term Investments
Assets
Investments, Adjusted Cost	17,645	17,898
Investments, Unrealized Gains	4
Investments, Unrealized Losses	(13)	(6)
Investments, Fair Value	17,636	17,892
Fair Value Measurements Recurring \| Level 2 \| U.S. Government Securities \| Short-term Investments
Assets
Investments, Adjusted Cost	2,003	4,011
Investments, Unrealized Gains	5
Investments, Fair Value	2,008	4,011
Fair Value Measurements Recurring \| Level 2 \| Corporate Debt Securities \| Short-term Investments
Assets
Investments, Adjusted Cost	12,893	13,953
Investments, Unrealized Gains	4	1
Investments, Unrealized Losses	(3)	(6)
Investments, Fair Value	12,894	13,948
Fair Value Measurements Recurring \| Level 2 \| U.S. Agency Securities \| Short-term Investments
Assets
Investments, Adjusted Cost	38,498	32,776
Investments, Unrealized Gains	105	20
Investments, Unrealized Losses		(2)
Investments, Fair Value	38,603	32,794
Fair Value Measurements Recurring \| Level 2 \| Asset-backed Securities \| Short-term Investments
Assets
Investments, Adjusted Cost	2,199	4,598
Investments, Unrealized Losses	(1)
Investments, Fair Value	$ 2,198	$ 4,598

Fair Value Measurements - Additional Information (Details)	3 Months Ended
	Mar. 31, 2020 USD ($)
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	13 months
Maximum
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Long-term marketable debt securities maturity period	18 months
Long-term Investments
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Debt securities, aggregate cost basis	$ 13,200,000
Debt securities, fair value	$ 13,200,000

Fair Value Measurements - Schedule of Risk-free Interest Rate Based on U.S. Treasury Yield Curve Over Expected Term of Warrants (Details)	Mar. 31, 2020
Minimum
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Expected term (in years)	5 years 6 months
Maximum
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Expected term (in years)	7 years
Volatility \| Minimum
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Warrants measurement input	56.89
Volatility \| Maximum
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Warrants measurement input	57.24
Risk-free Interest Rate \| Minimum
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Warrants measurement input	2.25
Risk-free Interest Rate \| Maximum
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Warrants measurement input	2.31
Dividend Yield
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Warrants measurement input	0

Fair Value Measurements - Summary of Changes in Fair Value of Level 3 Financial Instruments (Details) - Level 3 - Warrant Liability $ in Thousands	3 Months Ended
	Mar. 31, 2019 USD ($)
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Balance	$ 683
Change in fair value	134
Balance	$ 817

Borrowings - Additional Information (Details) - USD ($)		1 Months Ended	3 Months Ended
Borrowings - Additional Information (Details) - USD ($)	Mar. 22, 2019	Jun. 30, 2017	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019	Jun. 30, 2019	Jun. 20, 2019
Debt Disclosure [Line Items]
Amounts outstanding under financing arrangements			$ 0		$ 0
Warrant issued to purchase stock							188,643
Common Stock
Debt Disclosure [Line Items]
Warrant exercisable term	7 years
Revolving Loan \| Series C Redeemable Convertible Preferred Stock
Debt Disclosure [Line Items]
Warrant issued to purchase stock		62,096
Warrant exercise price per share		$ 8.052
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 interest rate				15.23%
Estimated fair value of warrants	$ 600,000
Line of Credit Facility, Frequency of Payments			36 equal monthly payments of principal, plus accrued interest, from April 1, 2020 through March 1, 2023
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	65,502
Warrant exercise price per share	$ 9.16
Warrant exercisable term	7 years
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 \| Revolving Loan
Debt Disclosure [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity		$ 10,000,000
Line of credit outstanding		$ 5,000,000
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
Estimated fair value of warrants		$ 100,000
Debt Instrument, term		1 year 6 months
Interest expense				$ 200,000
Repayments of amount outstanding	$ 5,100,000
TriplePoint Capital LLC \| Revolving Loan \| Series C Redeemable Convertible Preferred Stock
Debt Disclosure [Line Items]
Warrant issued to purchase stock		62,096
Warrant exercise price per share		$ 8.052
Warrant exercisable term		7 years
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 \| Prime Rate \| Revolving Loan
Debt Disclosure [Line Items]
Interest rate, prime rate plus		6.75%

Leases - Additional Information (Details) $ in Thousands	1 Months Ended			3 Months Ended
Leases - Additional Information (Details) $ in Thousands	Apr. 30, 2020 USD ($)	Aug. 31, 2019	Feb. 28, 2015 ft²	Mar. 31, 2020 USD ($)	Mar. 31, 2019 USD ($)	Dec. 31, 2019 USD ($)	Sep. 30, 2019 USD ($)
Lessee Lease Description [Line Items]
Area of office space \| ft²			31,280
Lease expiration date			Nov. 30, 2020
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 right-of-use assets				$ 1,529		$ 1,845
Lease liability				1,663
Operating lease cost				300	$ 200
Cash paid for operating lease liabilities				$ 400	$ 300
Weighted average remaining lease term				1 year 7 months 6 days
Weighted average incremental borrowing rate				7.20%
Future minimum lease payments				$ 1,761
Co-located Data Center Space
Lessee Lease Description [Line Items]
Lease expiration date		Sep. 01, 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
Incremental borrowing rate							6.60%
Operating lease right-of-use assets							$ 1,100
Lease liability							$ 1,100
Co-located Data Center Space \| Subsequent Event
Lessee Lease Description [Line Items]
Percentage of modified data center space	57.00%
Minimum lease payments increased for remainder of lease term	$ 500
Laboratory and Office Space Lease
Lessee Lease Description [Line Items]
Incremental borrowing rate				8.00%
Lease term extended				December 2020 through November 2027
Laboratory and Office Space Lease \| Subsequent Event
Lessee Lease Description [Line Items]
Operating lease, option to extend	three years
Extension term	7 years
Future minimum lease payments	$ 14,800
Lease term extension commencement date	Dec. 01, 2020

Leases - Schedule of Future Minimum Lease Payments (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Leases [Abstract]
2020 (remaining nine months)	$ 1,039
2021	403
2022	319
Total future minimum lease payments	1,761
Less: imputed interest	(98)
Present value of future minimum lease payments	1,663
Less: current portion of operating lease liability	(1,107)	$ (1,361)
Operating lease liabilities - noncurrent	$ 556

Redeemable Convertible Preferred Stock - Summary of Redeemable Convertible Preferred Stock Outstanding (Details) $ in Thousands	Dec. 31, 2018 USD ($) 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 Preferred Stock - Additional Information (Details) - IPO - shares		3 Months Ended
	Jun. 20, 2019	Mar. 31, 2020
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 Company’s June 2019 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

- Definition

Specific terms relevant to convertibility. Includes class of preferred stock and number of shares convertible into, exercise (or conversion) price or rates, dates relevant to conversion timing and events relevant to conversion. Describe also any beneficial conversion features. where convertible preferred stock with a nondetachable conversion feature is in-the-money at commitment date. For contingently convertible preferred stock, discuss the circumstances of the contingency, including the events or changes in circumstance that would cause the contingency to be met and any of the significant features necessary to understand the conversion rights and the timing of those rights. Include also an events or changes in circumstance, if any, that could adjust or change the contingency, conversion price, or number of shares, including significant terms of those changes.

+ References + Details

Stock-Based Compensation - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Jan. 01, 2020	Dec. 31, 2019
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unvested shares subject to repurchase rights	0			0
Closing price of common stock	$ 8.07
Weighted-average grant date fair value of options granted	$ 3.46	$ 7.76
Unrecognized stock-based compensation cost of unvested options	$ 10,500
Unrecognized stock-based compensation of unvested options, recognized over weighted-average period	2 years 8 months 12 days
Share-based compensation expense	$ 1,249	$ 609
Weighted-average expected life		6 years 10 months 13 days
Expected volatility		56.20%
Dividend yield	0.00%	0.00%
Restricted Stock Units
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting period	4 years
Closing price of common stock	$ 8.07
Unrecognized stock-based compensation of unvested options, recognized over weighted-average period	2 years 10 months 24 days
Share-based compensation expense	$ 100
Unrecognized stock-based compensation cost of unvested RSUs	$ 2,400
Restricted Stock Units \| Tranche One
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 29 days
Minimum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Weighted-average expected life	5 years 9 months 7 days
2011 Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting period	4 years
2011 Plan \| Tranche One
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting period	1 year
Vesting rate at the end of one year	25.00%
2011 Plan \| ISO
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Percentage of exercise price granted to stockholder	10.00%
2011 Plan \| Options Granted as Merit Awards
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting period	4 years
2011 Plan \| Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Options granted in years	10 years
2011 Plan \| Minimum \| ISO
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Percentage of exercise price options granted	110.00%
2019 Plan \| 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%
Closing price of common stock	$ 8.07
Unrecognized stock-based compensation cost of unvested options	$ 1,400
Unrecognized stock-based compensation of unvested options, recognized over weighted-average period	4 years 6 months
Weighted-average expected life	10 years
Expected volatility	63.60%
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 \| 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]
Share-based compensation expense	$ 100
Common stock shares reserved for issuance	484,746		312,430
Percentage of purchase price of common stock	85.00%
Common stock shares purchased	0
Weighted-average expected life	6 months
Expected volatility	59.90%
Risk-free interest rate	1.60%
Dividend yield	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%

Stock-Based Compensation - Summary of Shares of Common Stock Available for Issuance (Details) - shares

Mar. 31, 2020

Dec. 31, 2019

2011 Plan

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Reserved for issuance upon exercise of options outstanding

4,173,216

4,474,057

2019 Plan

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Reserved for issuance upon exercise of options outstanding

1,283,674

257,378

Issuance under 2019 Plan

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Shares of stock options reserved for issuance

^[1]

2,654,524

2,392,343

2011 Plan and 2019 Plan

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Reserved for issuance upon exercise of options outstanding

5,035,890

4,731,435

Total number of shares reserved

8,518,515

7,243,778

Restricted Stock Units | 2019 Plan

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Shares of unvested RSUs

407,101

120,000

[1]	Includes share increase added January 1, 2020 pursuant to the “evergreen” provision in the amount of 1,562,151 shares

Stock-Based Compensation - Summary of Shares of Common Stock Available for Issuance (Parenthetical) (Details)	Jan. 01, 2020 shares
Issuance under 2019 Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Increase in number of reserved shares	1,562,151

Stock-Based Compensation - Summary of Stock Option Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2020	Dec. 31, 2019
2011 Plan and 2019 Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Outstanding Options, Number of Shares, Beginning Balance	4,731,435
Outstanding Options, Number of Shares, granted	616,796
Outstanding Options, Number of Shares, exercised	(277,415)
Outstanding Options, Number of Shares, cancelled	(34,926)
Outstanding Options, Number of Shares, Ending Balance	5,035,890	4,731,435
Options vested and exercisable, Number of Shares	2,785,380
Outstanding Options, Weighted-Average Exercise Price, Beginning Balance	$ 4.94
Outstanding Options, Weighted-Average Exercise Price, granted	6.07
Outstanding Options, Weighted-Average Exercise Price, exercised	1.16
Outstanding Options, Weighted-Average Exercise Price, cancelled	10.22
Outstanding Options, Weighted-Average Exercise Price, Ending Balance	5.25	$ 4.94
Options vested and exercisable, Weighted-Average Exercise Price	$ 3.46
Outstanding Options, Weighted-Average Remaining Contractual Term (in years)	6 years 11 months 4 days	6 years 7 months 6 days
Options vested and exercisable, Weighted-Average Remaining Contractual Term (in years)	5 years 3 months 10 days
Outstanding Options, Aggregate Intrinsic Value	$ 17,953	$ 29,730
Options vested and exercisable, Aggregate Intrinsic Value	$ 13,745
2019 Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Outstanding Options, Number of Shares, Beginning Balance	257,378
Outstanding Options, Number of Shares, Ending Balance	1,283,674	257,378
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
Outstanding Options, Weighted-Average Exercise Price, granted	$ 5.10
Outstanding Options, Weighted-Average Exercise Price, Ending Balance	$ 5.10
Outstanding Options, Weighted-Average Remaining Contractual Term (in years)	9 years 11 months 15 days
Outstanding Options, Aggregate Intrinsic Value	$ 1,250

Stock-Based Compensation - Summary of Weighted-average Assumptions Used in Determination of Fair Value of Service-Based Stock Options (Details) - $ / shares	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected term (in years)		6 years 10 months 13 days
Volatility		56.20%
Volatility, minimum	61.74%
Volatility, maximum	64.13%
Risk-free interest rate, minimum	0.58%	2.49%
Risk-free interest rate, maximum	1.66%	2.52%
Dividend yield	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
Volatility	63.60%
Derived service period (in years)	4 years 6 months 18 days
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 9 months 7 days
Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected term (in years)	6 years 29 days

Stock-Based Compensation - Summary of Restricted Stock Unit Activity (Detail) - Restricted Stock Units - 2019 Plan $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2020 USD ($) $ / shares shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unvested Restricted Stock Units, Number of Shares, Beginning Balance \| shares	120,000
Unvested Restricted Stock Units, Number of Shares, granted \| shares	297,100
Unvested Restricted Stock Units, Number of Shares, vested \| shares	(9,999)
Unvested Restricted Stock Units, Number of Shares, Ending Balance \| shares	407,101
Unvested Restricted Stock Units, Weighted-Average Grant Date Fair Value, Beginning Balance \| $ / shares	$ 8.86
Unvested Restricted Stock Units, Weighted-Average Grant Date Fair Value, granted \| $ / shares	4.88
Unvested Restricted Stock Units, Weighted-Average Grant Date Fair Value, vested \| $ / shares	8.86
Unvested Restricted Stock Units, Weighted-Average Grant Date Fair Value, Ending Balance \| $ / shares	$ 5.95
Unvested Restricted Stock Units, Aggregate Fair Value \| $	$ 1,308
Unvested Restricted Stock Units, Aggregate Fair Value \| $	98
Unvested Restricted Stock Units, Aggregate Fair Value \| $	$ 3,285

Stock-Based Compensation - Summary of Stock-Based Compensation Expense by Function (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based compensation expense	$ 1,249	$ 609
Costs of revenues
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based compensation expense	143	85
Research and development
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based compensation expense	259	164
Selling, general, and administrative
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based compensation expense	$ 847	$ 360

Redeemable Convertible Preferred Stock Warrants - Additional Information (Details) $ / shares in Units, $ in Millions	1 Months Ended	6 Months Ended
	Jun. 30, 2017 USD ($) $ / shares shares	Jun. 30, 2019 shares	Mar. 31, 2020 USD ($) shares	Jun. 20, 2019 shares	Dec. 31, 2018 USD ($)	Sep. 30, 2014 $ / shares shares
Convertible Preferred Stock Warrants [Line Items]
Warrant issued to purchase stock				188,643
Fair values of convertible preferred stock warrants \| $					$ 0.7
Fair value transferred to additional paid-in capital \| $			$ 2.1
Common stock warrant exercised		22,489
Common stock issued for exercise of warrant		19,069
Common Stock
Convertible Preferred Stock Warrants [Line Items]
Warrant outstanding			62,096
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 \| $ / shares						$ 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 \| $ / shares	$ 8.052
Contractual term	7 years
Estimated fair value of warrants \| $	$ 0.1
Series C Redeemable Convertible Preferred Stock \| Revolving Loan \| Risk-free Interest Rate
Convertible Preferred Stock Warrants [Line Items]
Warrants and rights outstanding, measurement input	1.97
Series C Redeemable Convertible Preferred Stock \| Revolving Loan \| Volatility
Convertible Preferred Stock Warrants [Line Items]
Warrants and rights outstanding, measurement input	64.33
Series C Redeemable Convertible Preferred Stock \| Revolving Loan \| Dividend Yield
Convertible Preferred Stock Warrants [Line Items]
Warrants and rights outstanding, measurement input	0

Common Stock Warrants - Additional Information (Details) - USD ($) $ / shares in Units, $ in Millions	Mar. 22, 2019	Mar. 31, 2020	Jun. 20, 2019	Aug. 31, 2011
Common Stock Warrants [Line Items]
Warrant issued to purchase stock			188,643
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
Common Stock Warrants [Line Items]
Warrants outstanding		62,096
Warrant exercisable term	7 years
Common Stock \| TriplePoint Capital LLC
Common Stock Warrants [Line Items]
Warrant issued to purchase stock	65,502
Warrant exercise price per share	$ 9.16
Warrant exercisable term	7 years
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 Attributable to Common Stockholders - Schedule of Basic and Diluted Net Loss per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Numerator:
Net loss attributable to common stockholders	$ (9,139)	$ (5,685)
Denominator:
Weighted-average shares outstanding	31,345,029	3,091,504
Less: weighted-average shares subject to repurchase	0	(162)
Weighted-average shares outstanding used in computing net loss per share attributable to common stockholders — basic and diluted	31,345,029	3,091,342
Net loss per share, basic and diluted	$ (0.29)	$ (1.84)

Net Loss per Share Attributable to Common Stockholders - Schedule of Dilutive Securities Excluded from Computation of Diluted Net Loss per Share (Details) - shares	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potentially dilutive securities excluded from computation of diluted net loss per share	6,062,009	23,196,372
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	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	127,598	254,145
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	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	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	5,456,890	4,381,884
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	407,101	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	70,420	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	1,016