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Cover - shares	3 Months Ended
Cover - shares	Mar. 31, 2020	May 08, 2020
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Mar. 31, 2020
Document Transition Report	false
Entity File Number	001-39049
Entity Registrant Name	EXAGEN INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	20-0434866
Entity Central Index Key	0001274737
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q1
Amendment Flag	false
Entity Address, Address Line One	1261 Liberty Way,
Entity Address, Address Line Two	Suite C
Entity Address, City or Town	Vista,
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	92081
City Area Code	(760)
Local Phone Number	560-1501
Title of 12(b) Security	Common Stock, par value $0.001 per share
Trading Symbol	XGN
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Ex Transition Period	false
Entity Interactive Data Current	Yes
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		12,640,217

Condensed Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Current assets:
Cash and cash equivalents	$ 68,648	$ 72,084
Accounts receivable, net	5,843	5,715
Prepaid expenses and other current assets	3,084	3,451
Total current assets	77,575	81,250
Property and equipment, net	1,376	1,380
Goodwill	5,506	5,506
Other assets	187	174
Total assets	84,644	88,310
Current liabilities:
Accounts payable	2,566	1,476
Accrued liabilities	4,763	4,419
Total current liabilities	7,329	5,895
Borrowings-non-current portion, net of discounts and debt issuance costs	26,050	25,854
Deferred tax liabilities	147	264
Other non-current liabilities	581	638
Total liabilities	34,107	32,651
Commitments and contingencies (Note 5)
Stockholders’ equity:
Preferred stock	0	0
Common stock	13	13
Additional paid-in capital	220,689	220,248
Accumulated deficit	(170,165)	(164,602)
Total stockholders' equity	50,537	55,659
Total liabilities and stockholders' equity	$ 84,644	$ 88,310

Condensed Balance Sheets (Parenthetical) - $ / shares	Mar. 31, 2020	Dec. 31, 2019
Preferred stock
Par value (in dollars per share)	$ 0.001	$ 0.001
Shares authorized (in shares)	10,000,000
Shares issued (in shares)	0
Shares outstanding (in shares)	0
Common stock
Par value (in dollars per share)	$ 0.001	$ 0.001
Shares authorized (in shares)	200,000,000
Shares issued (in shares)	12,627,056	12,560,990
Shares outstanding (in shares)	12,627,056	12,560,990

Unaudited Condensed Statements of Operations - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Income Statement [Abstract]
Revenue	$ 9,584	$ 9,260
Operating expenses:
Costs of revenue (excluding amortization of purchased technology)	4,545	4,442
Selling, general and administrative expenses	9,626	6,179
Research and development expenses	634	513
Total operating expenses	14,805	11,134
Loss from operations	(5,221)	(1,874)
Interest expense	631	901
Other income, net	171	71
Loss from operations	(5,681)	(2,704)
Income tax benefit	118	0
Net loss	(5,563)	(2,704)
Accretion of redeemable convertible preferred stock	0	(2,114)
Net loss attributable to common stockholders (diluted)	$ (5,563)	$ (4,818)
Net loss per share:
Net loss per share, basic and diluted (USD per share)	$ (0.44)	$ (76.46)
Weighted average shares:
Weighted-average number of shares used to compute net loss per share, basic and diluted (in shares)	12,595,715	63,016

Unaudited Condensed Statements of Redeemable Convertible Preferred Stock and Stockholders' Equity (Deficit) - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Deficit
Beginning balance (in shares) at Dec. 31, 2018	532,606,084
Beginning balance at Dec. 31, 2018	$ 105,232
Increase (Decrease) in Temporary Equity [Roll Forward]
Accretion of redeemable convertible preferred stock	$ 2,114
Issuance of Series G redeemable convertible preferred stock for aggregate proceeds, net of issuance costs (in shares)	97,646,289
Issuance of Series G redeemable convertible preferred stock for aggregate proceeds, net of issuance costs	$ 7,520
Ending balance (in shares) at Mar. 31, 2019	630,252,373
Ending balance at Mar. 31, 2019	$ 114,866
Beginning balance (in shares) at Dec. 31, 2018		63,005
Beginning balance at Dec. 31, 2018	(111,966)	$ 0	$ 40,598	$ (152,564)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Accretion of redeemable convertible preferred stock	(2,114)		(2,114)
Exercise of stock options (in shares)		24
Exercise of stock options	0	$ 0
Stock-based compensation	12		12
Net loss	(2,704)			(2,704)
Ending balance (in shares) at Mar. 31, 2019		63,029
Ending balance at Mar. 31, 2019	(116,772)	$ 0	38,496	(155,268)
Increase (Decrease) in Temporary Equity [Roll Forward]
Accretion of redeemable convertible preferred stock	$ 0
Beginning balance (in shares) at Dec. 31, 2019	12,560,990	12,560,990
Beginning balance at Dec. 31, 2019	$ 55,659	$ 13	220,248	(164,602)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of stock options (in shares)	43,700	43,700
Exercise of stock options	$ 10		10
Stock-based compensation	431		431
Net exercise of common stock warrants (in shares)		22,366
Net exercise of common stock warrants	0
Net loss	$ (5,563)			(5,563)
Ending balance (in shares) at Mar. 31, 2020	12,627,056	12,627,056
Ending balance at Mar. 31, 2020	$ 50,537	$ 13	$ 220,689	$ (170,165)

Unaudited Condensed Statements of Redeemable Convertible Preferred Stock and Stockholders' Equity (Deficit) (Parenthetical) - Series G redeemable convertible preferred stock $ in Thousands	3 Months Ended
	Mar. 31, 2019 USD ($) $ / shares
Sale of temporary equity, price per share (in dollars per share) \| $ / shares	$ 0.078
Issuance costs \| $	$ 96

Unaudited Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
Unaudited Statements of Cash Flows - USD ($) $ in Thousands	Mar. 31, 2020	Mar. 31, 2019
Cash flows from operating activities:
Net loss	$ (5,563)	$ (2,704)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	126	182
Amortization of debt discount and debt issuance costs	65	201
Deferred income taxes	(117)	0
Non-cash interest expense	131	159
Loss on disposal of assets	0	4
Stock-based compensation	431	12
Changes in assets and liabilities:
Accounts receivable, net	(128)	(487)
Prepaid expenses and other current assets	367	378
Other assets	(14)	0
Accounts payable	1,054	145
Accrued and other liabilities	347	160
Net cash used in operating activities	(3,301)	(1,950)
Cash flows from investing activities:
Purchases of property and equipment	(84)	(363)
Net cash used in investing activities	(84)	(363)
Cash flows from financing activities:
Proceeds from sale of common stock upon exercise of stock options	10	0
Principal payment on capital lease obligations	(61)	(20)
Payments of deferred offering costs	0	(274)
Net cash (used in) provided by financing activities	(51)	3,476
Net change in cash, cash equivalents and restricted cash	(3,436)	1,163
Cash, cash equivalents and restricted cash, beginning of period	72,184	13,264
Cash, cash equivalents and restricted cash, end of period	68,748	14,427
Supplemental disclosure of cash flow information:
Cash paid for interest expense	432	502
Supplemental disclosure of non-cash items:
Accretion to redemption value of redeemable convertible preferred stock	0	2,114
Equipment Purchased Under Capital Lease	2	0
Cost incurred, but not paid, in connection with capital expenditures	37	12
Deferred offering costs included in accounts payable and accrued liabilities	0	750
Series G redeemable convertible preferred stock
Cash flows from financing activities:
Proceeds from issuance of redeemable convertible preferred stock, net of issuance costs	$ 0	$ 3,770

Organization	3 Months Ended
Organization	Mar. 31, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization	Organization Description of Business Exagen Inc. (the Company) was incorporated under the laws of the state of New Mexico in 2002, under the name Exagen Corporation. In 2003, Exagen Corporation changed its state of incorporation from New Mexico to Delaware by merging with and into Exagen Diagnostics, Inc., pursuant to which the Company changed its name to Exagen Diagnostics, Inc. In January 2019, the Company changed its name to Exagen Inc. The Company is dedicated to transforming the care continuum for patients suffering from debilitating and chronic autoimmune diseases by enabling timely differential diagnosis and optimizing therapeutic intervention. Liquidity The Company has suffered recurring losses and negative cash flows from operating activities since inception. The Company anticipates that it will continue to incur net losses into the foreseeable future. At March 31, 2020, the Company had cash and cash equivalents of $68.6 million and had an accumulated deficit of $170.2 million, respectively. Since inception, the Company has financed its operations primarily through private placements of preferred securities, the sale of common stock through its initial public offering (IPO) and debt financing arrangements. Based on the Company's current business plan, management believes that its existing capital resources will be sufficient to fund the Company's obligations for at least twelve months following the issuance of these financial statements. To execute its business plans, the Company may need additional funding to support its continuing operations and pursue its growth strategy. Until such time as the Company can achieve significant cash flows from operations, if ever, it expects to finance its operations through the sale of its stock, debt financings or other strategic transactions. Although the Company has been successful in raising capital in the past, there is no assurance that it will be successful in obtaining such additional financing on terms acceptable to the Company, if at all. The terms of any financing may adversely affect the holdings or the rights of the Company's stockholders. If the Company is unable to obtain funding, the Company could be forced to delay, reduce or eliminate some or all of its programs, product portfolio expansion plans or commercialization efforts, which could have a material adverse effect on the Company's business, operating results and financial condition and the Company's ability to achieve its intended business objectives.

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 and Use of Estimates

The accompanying interim condensed balance sheet as of March 31, 2020, the condensed statements of operations and the condensed statements of redeemable convertible preferred stock and stockholders' equity (deficit) for the three months ended March 31, 2020 and 2019 and cash flows for the three months ended March 31, 2020 and 2019 and the related footnote disclosure are unaudited and have been prepared in accordance with the rules and regulations of the Securities and Exchange Commission (SEC), and with accounting principles generally accepted in the United States (GAAP) applicable to interim financial statements. In management's opinion, the unaudited interim condensed financial statements have been prepared on the same basis as the audited financial statements and include all adjustments, which include only normal recurring adjustments, necessary for the fair presentation of the Company's financial position as of March 31, 2020 and its results of operations for the three months ended March 31, 2020 and 2019 and cash flows for the three months ended March 31, 2020 and 2019 in accordance with GAAP. The results for the three months ended March 31, 2020 are not necessarily indicative of the results expected for the full fiscal year or any other interim period. The year-end condensed balance sheet data was derived from audited financial statements, but does not include all disclosures required by accounting principles generally accepted in the United States of America. These unaudited condensed financial statements should be

read in conjunction with the Company’s audited financial statements for the year ended December 31, 2019, included in its Annual Report on Form 10-K filed with the SEC on March 25, 2020.

The preparation of the accompanying condensed financial statements requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities as of the date of the condensed financial statements, and the reported amounts of revenue and expenses during the reporting period. Actual results could materially differ from those estimates.

Significant estimates and assumptions made in the accompanying condensed financial statements include, but are not limited to revenue recognition, the fair value of financial instruments measured at fair value, the recoverability of its long-lived assets (including goodwill), net deferred tax assets (and related valuation allowance), and for periods prior to the IPO, the fair value of the Company's common stock and redeemable convertible preferred stock. The Company evaluates its estimates and assumptions on an ongoing basis using historical experience and other factors and adjusts those estimates and assumptions when facts and circumstances dictate. Actual results could materially differ from those estimates.

Concentration of Credit Risk and Other Risk and Uncertainties

Financial instruments that potentially subject the Company to credit risk consist principally of cash, cash equivalents, and accounts receivable. Substantially all the Company's cash and cash equivalents are held at one financial institution that management believes is of high credit quality. Such deposits may, at times, exceed federally insured limits.

Significant payers and customers are those which represent more than 10% of the Company's total revenue or accounts receivable balance at each respective balance sheet date. For each significant payer and customer, revenue as a percentage of total revenue and accounts receivable as a percentage of total accounts receivable are as follows:


	Revenue
	Three Months Ended March 31,
	2020		2019
Medicare	25	%	26	%
Blue Shield	12	%	13	%
United Healthcare	10	%	11	%
Medicare Advantage	13	%	10	%


	Accounts Receivable
	March 31, 2020		December 31, 2019


United Healthcare	22	%	22	%
Blue Shield	14	%	15	%

Janssen (SIMPONI^®)	*		19	%



*						Less than 10%.

For the three months ended March 31, 2020 and 2019, approximately 83%, and 85%, respectively, of the Company's revenue was related to the AVISE^® CTD test.

The Company is dependent on key suppliers for certain laboratory materials. For the three months ended March 31, 2020 and 2019, approximately 96% and 94%, respectively, of the Company's inventories were purchased from two suppliers. An interruption in the supply of these materials would impact the Company's ability to perform testing services.

Disaggregation of Revenue

The following table includes the Company's revenues as disaggregated by payer and customer category (in thousands):


	Three Months Ended March 31,
	2020		2019
Revenue:
Healthcare insurers	$	6,062	$	5,461
Government	2,245		2,432
Client	1,082		1,105
Other(1)	195		162
Janssen (SIMPONI^®)	—		100
Total revenue	$	9,584	$	9,260

(1)Includes patient self-pay that is immaterial.

Fair Value Measurements

The carrying value of the Company's cash and cash equivalents, other assets and accrued liabilities approximate fair value due to the short-term nature of these items. Based on the borrowing rates currently available to the Company for debt with similar terms and consideration of default and credit risk, the carrying value of the Company's long-term borrowings approximates its fair value, which is considered a Level 2 input.

Fair value is defined as the exchange price that would be received for an asset or an exit price paid to transfer a liability in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. Valuation techniques used to measure fair value must maximize the use of observable inputs and minimize the use of unobservable inputs.

The fair value hierarchy defines a three-level valuation hierarchy for disclosure of fair value measurements as follows:

Level 1 - Unadjusted quoted prices in active markets for identical assets or liabilities;

Level 2 - Inputs other than quoted prices included within Level I that are observable, unadjusted quoted prices in markets that are not active, or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the related assets or liabilities; and

Level 3 - Unobservable inputs that are supported by little or no market activity for the related assets or liabilities.

The categorization of a financial instrument within the valuation hierarchy is based upon the lowest level of input that is significant to the fair value measurement.

Cash, Cash Equivalents and Restricted Cash

The Company considers all highly-liquid investments purchased with a remaining maturity date upon acquisition of three months or less to be cash equivalents and are stated at cost, which approximates fair value.

In 2016, the Company entered into an arrangement with a financial institution with which it has an existing banking relationship whereby in exchange for the issuance of corporate credit cards, the Company agreed to obtain a $0.1 million certificate of deposit with this financial institution as collateral for the balances borrowed on these credit cards. The Company has classified the value of this certificate of deposit (including all interest earned thereon) within other assets in the accompanying balance sheets. The Company has the right to terminate the credit card program at any time. Upon termination of the credit card program and repayment of all outstanding balances owed, the Company may redeem the certificate of deposit (and all interest earned thereon).

Cash, cash equivalents and restricted cash presented in the accompanying condensed statements of cash flows consist of the following (in thousands):


	March 31, 2020		December 31, 2019

Cash and cash equivalents	$	68,648	$	72,084
Restricted cash	100		100
	$	68,748	$	72,184

Revenue Recognition

Substantially all of the Company's revenue has been derived from sales of its testing products and is primarily comprised of a high volume of relatively low-dollar transactions. The Company primarily markets its testing products to rheumatologists and their physician assistants in the United States. The healthcare professionals who order the Company's testing products and to whom test results are reported are generally not responsible for payment for these products. The parties that pay for these services (the Payers) consist of healthcare insurers, government payers (primarily Medicare and Medicaid), client payers (i.e., hospitals, other laboratories, etc.), and patient self-pay. The Company's service is a single performance obligation that is completed upon the delivery of test results to the prescribing physician which triggers revenue recognition.

Payers are billed at the Company's list price. Net revenues recognized consist of amounts billed net of allowances for differences between amounts billed and the estimated consideration the Company expects to receive from such payers. The process for estimating revenues and the ultimate collection of accounts receivable involves significant judgment and estimation. The Company follows a standard process, which considers historical denial and collection experience, insurance reimbursement policies and other factors, to estimate allowances and implicit price concessions, recording adjustments in the current period as changes in estimates. Further adjustments to the allowances, based on actual receipts, is recorded upon settlement. The transaction price is estimated using an expected value method on a portfolio basis. The Company's portfolios are grouped per payer (i.e. each individual third-party insurance, Medicare, client payers, patient self-pay, etc.) and per test basis.

Collection of the Company's net revenues from payers is normally a function of providing complete and correct billing information to the healthcare insurers and generally occurs within 30 to 90 days of billing. Contracts do not contain significant financing components based on the typical period of time between performance of services and collection of consideration.

Janssen Promotion Agreement

In December 2018, the Company entered into a co-promotion agreement with Janssen Biotech, Inc. (Janssen) to co-promote SIMPONI^® in the United States (the Janssen Agreement). The Company is responsible for the costs associated with its salesforce over the course of such co-promotion. Janssen is responsible for all other aspects of the commercialization of SIMPONI^® under the Janssen agreement. In exchange for the Company's sales and co-promotional services, the Company is entitled to a quarterly tiered promotion fee ranging from $750 to $1,250 per prescription based on the incremental increase in total prescribed units of SIMPONI^® for that quarter over a predetermined baseline. The promotion fee is determined on a sliding rate, ranging from the high hundreds of dollars to the low one thousands per prescribed unit of SIMPONI^®, depending on the number of increased prescriptions, and varies per increased prescription. In addition, during the term of the Janssen agreement, the Company is restricted from promoting any other biologic or Janus kinase inhibitor, or JAK inhibitor, used for treatment of indications covered by the agreement without first obtaining Janssen's written consent.

In September 2019, the Company exercised its option to extend the term of the Janssen Agreement to December 31, 2021. Janssen may terminate the Janssen Agreement at any time for any reason upon 30 days' notice to the Company, and the Company may terminate the Janssen Agreement for any reason at the end of any calendar quarter upon 30 days' notice to Janssen. Either party may terminate the Janssen Agreement in the event of the other party's default of any of its material obligations under the agreement if such default remains uncured for a specified period of time following receipt of written notice of such default.

The Company's obligations relating to sales and co-promotion services for SIMPONI^® is a series of single performance obligations since Janssen simultaneously receives and consumes benefits provided by the Company's

sales and co-promotional services. The method for measuring progress towards satisfying the performance obligations is based on prescribed units in excess of the contractual baseline at the contractual rate earned per unit since the agreement is cancelable. The Company recognized no co-promotional revenue and approximately $0.1 million during the three months ended March 31, 2020 and 2019, respectively. The related expenses for marketing SIMPONI^® are included in selling, general and administrative expenses and are expensed as incurred.

Research and Development

Costs associated with research and development activities are expensed as incurred and include, but are not limited to, personnel-related expenses, including stock-based compensation expense, materials, laboratory supplies, consulting costs, costs associated with setting up and conducting clinical studies and allocated overhead including rent and utilities.

Advertising and Marketing Costs

Costs associated with advertising and marketing activities are expensed as incurred. Total advertising and marketing costs were approximately $0.4 million and $0.3 million for the three months ended March 31, 2020 and 2019, respectively, and are included in selling, general and administrative expenses in the accompanying condensed statements of operations.

Shipping and Handling Costs

Costs incurred for shipping and handling are included in costs of revenue in the accompanying condensed statements of operations and totaled approximately $0.4 million for the three months ended March 31, 2020 and 2019.

Stock-Based Compensation

The Company recognizes compensation expense for all stock-based awards to employees and directors based on the grant-date estimated fair values over the requisite service period of the awards (usually the vesting period) on a straight-line basis. The fair value of stock options is determined using the Black-Scholes-Merton (BSM) option pricing model, which requires management to make certain assumptions regarding a number of complex and subjective variables. Equity award forfeitures are recorded as they occur.

The BSM option pricing model incorporates various estimates, including the fair value of the Company's common stock, expected volatility, expected term and risk-free interest rates. The weighted-average expected term of options was calculated using the simplified method. This decision was based on the lack of relevant historical data due to the Company's limited historical experience. In addition, due to the Company's limited historical data, the estimated volatility incorporates the historical volatility over the expected term of the award of comparable companies whose share prices are publicly available. The risk-free interest rate for periods within the contractual term of the option is based on the U.S. Treasury yield in effect at the time of grant. The dividend yield was zero, as the Company has never declared or paid dividends and has no plans to do so in the foreseeable future.

Upon the effective date of the IPO, the Company began using the closing price of its common stock as the fair value of its common stock on the corresponding date.

Comprehensive Loss

Comprehensive loss is defined as a change in equity of a business enterprise during a period, resulting from transactions from nonowner sources. There have been no items qualifying as other comprehensive loss and, therefore, for all periods presented, the Company's comprehensive loss was the same as its reported net loss.

Net Loss Per Share

Basic net loss per share attributable to common stockholders is calculated by dividing the net loss attributable to common stockholders by the weighted-average number of common shares outstanding during the period. Diluted net loss per share attributable to common stockholders is computed by dividing the net loss attributable to common stockholders by the weighted-average number of common stock equivalents outstanding for the period determined using the treasury-stock and if-converted methods. Potentially dilutive common stock equivalents are comprised of

redeemable convertible preferred stock, warrants for the purchase of redeemable convertible preferred and common stock and options outstanding under the Company's stock option plans. For the three months ended March 31, 2020 and 2019, there is no difference in the number of shares used to calculate basic and diluted shares outstanding as the inclusion of the potentially dilutive securities would be antidilutive.

Potentially dilutive securities not included in the calculation of diluted net loss per share because to do so would be anti-dilutive are as follows (in common stock equivalent shares):


	Three Months Ended March 31,
	2020	2019
Redeemable convertible preferred stock	—	5,734,680
Warrants to purchase redeemable convertible preferred stock	—	224,493
Warrants to purchase common stock	436,581	934,789
Common stock options	1,630,014	662,365
Total	2,066,595	7,556,327

Segment Reporting

Operating segments are identified as components of an enterprise about which separate discrete financial information is available for evaluation by the chief operating decision-maker in making decisions regarding resource allocation and assessing performance. The Company views its operations as, and manages its business in, one operating segment.

Recent Accounting Pronouncements

From time to time, new accounting pronouncements are issued by the Financial Accounting Standards Board (FASB), or other standard setting bodies and adopted by the Company as of the specified effective date. Under the Jumpstart Our Business Startups Act of 2012 (JOBS Act), the Company meets the definition of an emerging growth company. The Company has elected to use the extended transition period for complying with new or revised accounting standards pursuant to Section 107(b) of the JOBS Act. Unless otherwise discussed, the impact of recently issued standards that are not yet effective will not have a material impact on the Company's financial position or results of operations upon adoption.

In February 2016, the FASB issued Accounting Standards Update (ASU) 2016-02, Leases (Topic 842). The new topic supersedes Topic 840, Leases, and increases transparency and comparability among organizations by recognizing lease assets and lease liabilities on the balance sheet and requires disclosures of key information about leasing arrangements. In July 2018, the FASB issued ASU 2018-10, Codification Improvements to Topic 842, which provides narrow amendments to clarify how to apply certain aspects of the new lease standard, and ASU 2018-11, Leases: Targeted Improvements, which was issued to provide relief to companies from restating comparative periods. Pursuant to this ASU, in the period of adoption the Company will not restate comparative periods presented in its condensed financial statements. The effective date of this guidance for public companies is for reporting periods beginning after December 15, 2018. As an emerging growth company as defined in the JOBS Act, the Company has elected to delay adoption of this ASU until January 1, 2021. Topic 842 mandates a modified retrospective transition method. The Company intends to adopt the new lease standard using a cumulative effect to accumulated deficit and will elect the package of practical expedients, which among other things will allow the Company to carry forward its historical lease classification. The Company is currently evaluating the impact of Topic 842 on its condensed financial statements.

Recently Adopted Accounting Standards

In August 2018, the FASB issued ASU No. 2018-13, Fair Value Measurement: Disclosure Framework--Changes to the Disclosure Requirements for Fair Value Measurement, which adds and modifies certain disclosure requirements for fair value measurements. Under the new guidance, entities will no longer be required to disclose the amount of and reasons for transfers between Level 1 and Level 2 of the fair value hierarchy, or valuation processes for Level 3 fair value measurements. However, public companies will be required to disclose the range and weighted average of significant unobservable inputs used to develop Level 3 fair value measurements, and related changes in

unrealized gains and losses included in other comprehensive income. The narrative description of measurement uncertainty should be applied prospectively for only the most recent interim or annual period presented in the initial fiscal year of adoption. All other amendments should be applied retrospectively to all period presented upon their effective date. This update is effective for annual periods beginning after December 15, 2019, and interim periods within those periods, and early adoption is permitted. The Company adopted this guidance on January 1, 2020, and the adoption did not have a material impact on its condensed financial statements.

Other Financial Information

3 Months Ended

Mar. 31, 2020

Other Financial Information [Abstract]

Other Financial Information

Prepaid Expenses and Other Current Assets

Prepaid expenses and other current assets consist of the following (in thousands):


	March 31, 2020		December 31, 2019
Diagnostic testing supplies	$	1,299	$	1,427
Prepaid product royalties	110		123
Prepaid maintenance and insurance contracts	1,651		1,768
Other prepaid assets	24		133
Prepaid and other current assets	$	3,084	$	3,451

Property and Equipment

Property and equipment consist of the following (in thousands):


	March 31, 2020		December 31, 2019
Furniture and fixtures	$	32	$	25
Laboratory equipment	2,501		2,228
Computer equipment and software	891		851
Leasehold improvements	424		424
Construction in progress	49		247
Total property and equipment	3,897		3,775
Less: accumulated depreciation and amortization	(2,521)		(2,395)
Property and equipment, net	$	1,376	$	1,380

Depreciation and amortization expense for the three months ended March 31, 2020 and 2019 was approximately $0.1 million and $0.2 million, respectively. At March 31, 2020 and December 31, 2019, the gross book value of assets under capital lease was $1.1 million and $0.8 million, respectively, and is classified in "Laboratory equipment" in the table above.

Accrued Liabilities

Accrued liabilities consist of the following (in thousands):


	March 31, 2020		December 31, 2019
Accrued payroll and related expenses	$	2,733	$	2,362

Accrued interest	145		145
Accrued purchases of goods and services	282		319
Accrued royalties	407		727
Accrued clinical study activity	50		40
Capital lease obligations, current portion	241		238
Other accrued liabilities	905		588
Accrued liabilities	$	4,763	$	4,419

Borrowings

3 Months Ended

Mar. 31, 2020

Debt Disclosure [Abstract]

Borrowings

2017 Term Loan

In September 2017, the Company executed a term loan agreement (the 2017 Term Loan) with Innovatus Life Sciences Lending Fund I, LP (Innovatus) and borrowed $20.0 million, $17.8 million of which was immediately used to repay the Company's existing loan with Capital Royalty Partners II L.P. and its affiliates. On December 7, 2018, the Company borrowed an additional $5.0 million under the 2017 Term Loan. At March 31, 2020, no additional amounts remain available to borrow under the 2017 Term Loan.

In November 2019, the Company executed the First Amendment to the Loan and Security Agreement (Loan Amendment). The interest rate on all borrowings under the Loan Amendment is 8.5%, of which 2.0% is paid in-kind in the form of additional term loans (PIK Loans) until December of 2022, after which interest accrues at an annual rate of 8.5%. The Company has estimated the effective interest rate of this loan to be approximately 10%. Accrued interest is due and payable monthly, unless the Company elects to pay paid-in-kind interest. The outstanding principal and accrued interest on the Loan Amendment will be repaid in twenty-four equal monthly installments commencing in December 2022. Upon repayment of the final installment under the Loan Amendment, the Company is required to pay an additional fee of $1.0 million. This obligation is being accreted into interest expense over the term of Loan Amendment using the effective interest method. For the three months ended March 31, 2020 and 2019, the Company issued PIK Loans totaling $0.1 million and $0.2 million, respectively.

If the Loan Amendment is prepaid before November 19, 2020, the Loan Amendment requires a prepayment premium of 3% of the aggregate outstanding principal. The prepayment premium decreases by 1% during each subsequent twelve-month period after November 19, 2020.

The Loan Amendment is collateralized by a first priority security interest on substantially all of the Company's assets, including intellectual property. The affirmative covenants of the Loan Amendment require that the Company timely file taxes, maintain good standing and government compliance, maintain liability and other insurance, provide prompt notification of significant corporate events, and furnish audited financial statements within 150 days of fiscal year end without qualification as to the scope of the audit or as to going concern and without any other similar qualification.

The affirmative covenants require that the Company achieve a specified level of revenue, as measured quarterly on a rolling twelve-month basis, and commencing with the quarter ending December 31, 2019. The Company believes it is reasonably possible that it may fail to meet this affirmative covenant in the second or third quarter of 2020 as a result of the COVID-19 pandemic and its adverse impact on testing volumes. The consequences of failing to achieve the performance covenant will be waived if, within sixty days of failing to achieve the performance covenant, the Company issues additional equity securities or subordinated debt with net proceeds sufficient to fund any cash flow deficiency generated from operations, as defined. In addition, the Loan Amendment requires that the Company maintain certain levels of minimum liquidity. The Company is required to maintain an unrestricted cash balance of $2.0 million.

The negative covenants provide, among other things, that without the prior consent of Innovatus subject to certain exceptions, the Company may not dispose of certain assets, engage in certain business combinations or acquisitions, incur additional indebtedness or encumber any of the Company's property, pay dividends on the

Company's capital stock or make prohibited investments. The Loan Amendment agreement provides that an event of default will occur if, among other triggers, (i) the Company defaults in the payment of any amount payable under the agreement when due, (ii) there occurs any circumstance(s) that could reasonably be expected to result in a material adverse effect on the Company's business, operations or condition, or on the Company's ability to perform its obligations under the agreement, (iii) the Company becomes insolvent, (iv) the Company undergoes a change in control or (v) the Company breaches any negative covenants or certain affirmative covenants in the agreement or, subject to a cure period, otherwise neglects to perform or observe any material item in the agreement.

At March 31, 2020, the Company was in compliance with all covenants of the Loan Amendment.

Upon an event of default in any of the Loan Amendment covenants, the repayment of the Loan Amendment may be accelerated and the applicable interest rate will be increased by 4.0% until the default is cured. Although repayment of the Loan Amendment can be accelerated under certain circumstances, the Company believes acceleration of this loan is not probable as of the date of these condensed financial statements. Accordingly, the Company has reflected the amounts of the Loan Amendment due beyond twelve months of the balance sheet date as non-current.

Future Minimum Payments on the Outstanding Borrowings

As of March 31, 2020, future minimum aggregate payments, including interest, for outstanding borrowings under the Loan Amendment are as follows (in thousands):


	March 31, 2020
2020 (remaining)	$	1,299
2021	1,755
2022	2,996
2023	15,619
2024	14,280
Total	35,949
Less:
Unamortized debt discount and issuance costs	(367)
Interest	(9,532)
Total borrowings, net of discounts and debt issuance costs	$	26,050

Commitment and Contingencies	3 Months Ended
Commitment and Contingencies	Mar. 31, 2020
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Leases As of March 31, 2020, the Company leases an office and laboratory space in Vista, California, under leases that expire in January 2026, with an option to extend a portion of the lease for an additional 5-year period. In addition, the Company also leases an additional office space in Vista, California, under a lease that expires in January 2026 with an option to extend the lease for an additional 5-year period. The Company's lease payments under each of these leases are subject to escalation clauses. For the three months ended March 31, 2020 and 2019, rent expense was $0.1 million. Acquisition-related liabilities In connection with the acquisition of the medical diagnostics division of Cypress Bioscience, Inc. in 2010, the Company was required to pay certain amounts in the event that certain revenue milestones were achieved and upon the first commercial sale of a product associated with this acquisition. The acquisition also included amounts that may be due under several licensing agreements. All milestone payments other than one have been paid as of December 31, 2017. The remaining milestone obligation is for an additional $2.0 million payment due to Prometheus Laboratories, Inc. (Prometheus) for which the fair value was determined to be zero at March 31, 2020 and December 31, 2019. In addition, the Company has ongoing royalty payment obligations on net sales of products which incorporate certain acquired technologies ranging from 2.5% to 7.5%. Future royalties payable under these arrangements are limited to the lesser of an aggregate of $4.2 million (including an upfront payment of $100,000) or the total royalties earned through January 1, 2024. Licensing Agreements The Company has licensed technology for use in its diagnostic tests. In addition to the milestone payments required by these agreements as described above, individual license agreements generally provide for ongoing royalty payments on net sales of products which incorporate licensed technology, as defined, ranging from 3.0% to 20.0%. Royalties are accrued when earned and recorded in costs of revenue in the accompanying condensed statement of operations. Supply Agreement In 2019, the Company entered into an amended supply agreement with one supplier for reagents which includes a minimum annual purchase commitment of $4.2 million for each of the three years covered by the original agreement, which terminates in 2021. Contingencies 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; including subpoenas and other civil investigative demands, from governmental agencies, Medicare or Medicaid payers and managed care organizations reviewing billing practices or requesting comment on allegations of billing irregularities that are brought to their attention through billing audits or third parties. The Company's exposure under these agreements is unknown because it involves claims that may be made against the Company in the future, but have not yet been made. The Company accrues a liability for such matters when it is probable that future expenditures will be made and such expenditures can be reasonably estimated. Litigation The Company is not a party to any litigation and does not have contingent reserves established for any litigation liabilities. From time to time, the Company may be subject to various legal proceedings that arise in the ordinary course of business activities.

Fair Value Measurements

3 Months Ended

Mar. 31, 2020

Fair Value Disclosures [Abstract]

Fair Value Measurements

The following table sets forth the Company's financial instruments that were measured at fair value on a recurring basis within the fair value hierarchy (in thousands):


	March 31, 2020
	Total		Level 1		Level 2		Level 3
Assets:
Money market funds	$	67,431	$	67,431	$	—	$	—


	December 31, 2019
	Total		Level 1		Level 2		Level 3
Assets:
Money market funds	$	70,760	$	70,760	$	—	$	—

The fair value of the Company's money market funds is based on quoted market prices.

- 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

Redeemable Convertible Preferred Stock	3 Months Ended
Redeemable Convertible Preferred Stock	Mar. 31, 2020
Temporary Equity Disclosure [Abstract]
Redeemable Convertible Preferred Stock	Redeemable Convertible Preferred Stock Series G Financing In January 2019, the Company entered into an agreement with new and certain existing preferred stockholders to issue shares of Series G redeemable convertible preferred stock in multiple separate closings at a per share price of $0.078 in each closing. In conjunction with the issuance of the Series H redeemable convertible preferred stock, each share of issued and outstanding Series G redeemable convertible preferred stock was converted into shares of Series H redeemable convertible preferred stock. Upon completion of the Company's IPO in September 2019, an aggregate of 7,816,643 shares of common stock, excluding warrant conversions, were issued to the holders of the Company's Series A-3, Series B-3, Series C, Series D, Series E, Series F and Series H redeemable convertible preferred stockholders upon the automatic conversion of all shares of redeemable convertible preferred stock to common stock. As a result, no shares of redeemable convertible preferred stock remain outstanding at March 31, 2020.

Stockholders' Equity

3 Months Ended

Mar. 31, 2020

Equity [Abstract]

Stockholders' Equity

Outstanding Warrants

The following equity classified warrants to purchase common stock were outstanding as of March 31, 2020:

Exercise Price

Issuance date

Expiration date

Common stock warrants

259,975

1.84

January 19, 2016

January 19, 2026

Common stock warrants

71,753

1.84

March 31, 2016

March 31, 2026

Common stock warrants

131

1.84

April 1, 2016

April 1, 2026

Common stock warrants (1)

83,778

14.32

September 8, 2017

September 8, 2024

Common stock warrants (1)

20,944

14.32

December 7, 2018

December 7, 2025

436,581

(1) Prior to the conversion upon IPO, the remaining warrants were for the purchase of Series F redeemable convertible preferred stock.

During the first quarter of 2020, warrants to purchase common stock for 24,692 shares of the Company's common stock were exercised via cashless exercise resulting in the issuance of 22,366 shares of common stock

Stock Option Plan

3 Months Ended

Mar. 31, 2020

Share-based Payment Arrangement [Abstract]

Stock Option Plan

In September 2019, the Company's Board of Directors adopted, and the Company's stockholders approved, the 2019 Incentive Award Plan (the 2019 Plan). Under the 2019 Plan, the Company may grant stock options, stock appreciation rights, restricted stock, restricted stock units and other awards to individuals who are then employees, officers, non-employee directors or consultants of the Company or its subsidiaries. A total of (i) 2,011,832 shares of common stock plus (ii) shares subject to awards granted under the 2013 Plan on or before the effective date of the 2019 Plan became available for issuance under the 2019 Plan and will initially be reserved for issuance under the 2019 Plan. The 2019 Plan contains an "evergreen provision" that allows annual increases in the number of shares available for issuance on the first day of each calendar year through January 1, 2029 in an amount equal to the lesser of: (i) 4% of the outstanding capital stock on each December 31st, or (ii) such lesser amount as determined by the Board of Directors. As of March 31, 2020, 1,488,919 shares remained available for future awards.

The options generally expire ten years after the date of grant and are exercisable to the extent vested. Vesting is established by the Board of Directors and is generally four years from the date of grant.

Activity under the Company's stock option plans is set forth below:


	Number of Options	Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Term (Years)	Aggregate Intrinsic Value
Outstanding, December 31, 2019	1,375,542	$	8.33	9.16	$	23,654
Granted	514,131	$	19.51
Exercised	(43,700)	$	0.26
Forfeited	(215,542)	$	9.73
Expired	(417)	$	19.04
Outstanding, March 31, 2020	1,630,014	$	11.88	9.22	$	9,324
Vested and expected to vest, March 31, 2020	1,630,014	$	11.88	9.22	$	9,324
Options exercisable, March 31, 2020	199,168	$	3.77	7.90	$	2,740

The intrinsic value is calculated as the difference between the fair value of the Company's common stock and the exercise price of the stock options.

Stock-Based Compensation Expense

The fair value of employee stock options was estimated using the following assumptions to determine the fair value of stock options granted:


	Three Months Ended March 31,
	2020	2019
Expected volatility	47%-50%	59%
Risk-free interest rate	0.6%-1.7%	2.6%
Dividend yield	—	—
Expected term (in years)	6.08	6.08

Total non-cash stock-based compensation expense recorded related to options granted in the condensed statement of operations is as follows (in thousands):


	Three Months Ended March 31,
	2020		2019
Cost of revenue	$	6	$	1
Selling, general and administrative	422		10
Research and development	3		1
Total	$	431	$	12

As of March 31, 2020, total unrecognized compensation cost was $8.7 million, which is expected to be recognized over a remaining weighted-average vesting period of 3.3 years.

Related Parties	3 Months Ended
Related Parties	Mar. 31, 2020
Related Party Transactions [Abstract]
Related Parties	Related PartiesThe closings of the Series G financing described in Note 7 were issued to existing holders of the Company's redeemable convertible preferred stock, including certain members of our Board of Directors.

Covid-19	3 Months Ended
Covid-19	Mar. 31, 2020
Reorganizations [Abstract]
Covid-19	COVID-19The current COVID-19 worldwide pandemic has presented substantial public health challenges and is affecting the Company's employees, patients, physicians and other healthcare providers, communities and business operations, as well as the U.S. and global economies and financial markets. International and U.S. governmental authorities in impacted regions are taking actions in an effort to slow the spread of COVID-19, including issuing varying forms of "stay-at-home" orders, and restricting business functions outside of one's home. As a result of these limitations and reordering of priorities across the U.S. healthcare system, which have resulted in a reduction in patient flow, the Company's test volumes began to decrease in the second half of March 2020. From March 15 through March 31 and during April as compared to the same period a year ago, the Company has experienced AVISE^® CTD test volumes decreases of 12% and 56%, respectively. The Company expects its test volumes to continue to be adversely affected by COVID-19 and cannot predict when volumes will return to normal levels. In addition, the Company believes there are several other important factors that have impacted, and that it expects will impact its operating performance and results of operations, including shutdowns of its facilities and operations as well as those of its suppliers and courier services, disruptions to the supply chain of material needed for its tests, its sales and commercialization activities and its ability to receive specimens and perform or deliver the results from its tests, delays in reimbursement and coverage decisions from Medicare and third-party payors and in interactions with regulatory authorities, as well its inability to achieve volume-based pricing discounts with its key suppliers and absorb fixed laboratory expenses. In addition, the Company has experienced delays in patient enrollment for ongoing and planned clinical trials involving its tests. The Company may also experience a decrease or potential halt in shipments of its testing products as the Company's suppliers may be required to focus their resources to manufacture testing kits in response to the COVID-19 pandemic, which could in turn result in decreased gross margins. While it is too early to predict the full impact COVID-19 will have on the Company's business, the Company expects it to have a material impact on its financial results for at least the next quarter and potentially beyond, depending upon the timing of any lifting of COVID-19 limitations on the U.S. healthcare system and general economic recovery. In response to the COVID-19 pandemic, the Company has equipped most of its employees with the ability to work remotely with the exception of its clinical laboratory employees, and implemented measures to protect the health of its employees and to support the functionality of its clinical laboratory. In March 2020, as a result of the COVID-19 pandemic, the Company terminated temporary employees and six full-time employees, which included three employees at the vice president level. The termination of full-time employees resulted in the recognition of a restructuring charge for termination benefits of $0.3 million which has been paid as of May 2020. Additionally, as a result of the workforce reduction, the Company recognized a reversal of stock-based compensation expense of $0.1 million in March 2020. The restructuring charges were included in selling, general and administrative expenses in the condensed statements of operations. In addition, the Company has increased the use of virtual sales tools, halted employee travel, implemented work schedule reductions, instituted a temporary hiring freeze and scaled marketing spend. The full extent to which the COVID-19 pandemic will directly or indirectly continue to impact the Company's business, results of operations and financial condition, will depend on future developments that are highly uncertain, including as a result of new information that may emerge concerning COVID-19 and the actions taken to contain it or treat COVID-19, as well as the economic impact on local, regional, national and international markets. On March 27, 2020, the Coronavirus Aid, Relief, and Economic Security Act (CARES Act) was enacted in response to the COVID-19 pandemic. The CARES Act, among other things, permits NOL carryovers and carrybacks to offset 100% of taxable income for taxable years beginning before 2021. The CARES Act did not have a material impact on the Company's effective tax rate or income tax provision for the three months ended March 31, 2020. Under the Tax Cuts and Jobs Act (TCJA), NOLs generated post TCJA were allowed to be carried forward indefinitely but were only allowed to offset 80% of taxable income. As a result of the CARES Act and the change to permit NOLs generated in taxable years 2018, 2019 and 2020 to offset 100% of taxable income, the Company has released valuation allowance against its deferred tax assets in the amount of $0.1 million. The release of valuation allowance results in a discrete tax benefit of $0.1 million in the first quarter of 2020.

Subsequent Events	3 Months Ended
Subsequent Events	Mar. 31, 2020
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events On April 10, 2020, the Company received $0.7 million of funding under the CARES Act Provider Relief Fund, subject to the Company's agreement to comply with the Department of Health & Human Services' standard terms and conditions. These funds are not loans and will not be required to be repaid.

Summary Of Significant Accounting Policies - (Policy)	3 Months Ended
Summary Of Significant Accounting Policies - (Policy)	Mar. 31, 2020	Mar. 31, 2019
Accounting Policies [Abstract]
Concentration of Credit Risk and Other Risk and Uncertainties	Concentration of Credit Risk and Other Risk and Uncertainties Financial instruments that potentially subject the Company to credit risk consist principally of cash, cash equivalents, and accounts receivable. Substantially all the Company's cash and cash equivalents are held at one financial institution that management believes is of high credit quality. Such deposits may, at times, exceed federally insured limits.
Fair Value Measurements	Fair Value Measurements The carrying value of the Company's cash and cash equivalents, other assets and accrued liabilities approximate fair value due to the short-term nature of these items. Based on the borrowing rates currently available to the Company for debt with similar terms and consideration of default and credit risk, the carrying value of the Company's long-term borrowings approximates its fair value, which is considered a Level 2 input. Fair value is defined as the exchange price that would be received for an asset or an exit price paid to transfer a liability in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. Valuation techniques used to measure fair value must maximize the use of observable inputs and minimize the use of unobservable inputs. The fair value hierarchy defines a three-level valuation hierarchy for disclosure of fair value measurements as follows: Level 1 - Unadjusted quoted prices in active markets for identical assets or liabilities; Level 2 - Inputs other than quoted prices included within Level I that are observable, unadjusted quoted prices in markets that are not active, or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the related assets or liabilities; and Level 3 - Unobservable inputs that are supported by little or no market activity for the related assets or liabilities. The categorization of a financial instrument within the valuation hierarchy is based upon the lowest level of input that is significant to the fair value measurement.
Cash, Cash Equivalents and Restricted Cash	Cash, Cash Equivalents and Restricted Cash The Company considers all highly-liquid investments purchased with a remaining maturity date upon acquisition of three months or less to be cash equivalents and are stated at cost, which approximates fair value.
Revenue Recognition	Revenue Recognition Substantially all of the Company's revenue has been derived from sales of its testing products and is primarily comprised of a high volume of relatively low-dollar transactions. The Company primarily markets its testing products to rheumatologists and their physician assistants in the United States. The healthcare professionals who order the Company's testing products and to whom test results are reported are generally not responsible for payment for these products. The parties that pay for these services (the Payers) consist of healthcare insurers, government payers (primarily Medicare and Medicaid), client payers (i.e., hospitals, other laboratories, etc.), and patient self-pay. The Company's service is a single performance obligation that is completed upon the delivery of test results to the prescribing physician which triggers revenue recognition. Payers are billed at the Company's list price. Net revenues recognized consist of amounts billed net of allowances for differences between amounts billed and the estimated consideration the Company expects to receive from such payers. The process for estimating revenues and the ultimate collection of accounts receivable involves significant judgment and estimation. The Company follows a standard process, which considers historical denial and collection experience, insurance reimbursement policies and other factors, to estimate allowances and implicit price concessions, recording adjustments in the current period as changes in estimates. Further adjustments to the allowances, based on actual receipts, is recorded upon settlement. The transaction price is estimated using an expected value method on a portfolio basis. The Company's portfolios are grouped per payer (i.e. each individual third-party insurance, Medicare, client payers, patient self-pay, etc.) and per test basis. Collection of the Company's net revenues from payers is normally a function of providing complete and correct billing information to the healthcare insurers and generally occurs within 30 to 90 days of billing. Contracts do not contain significant financing components based on the typical period of time between performance of services and collection of consideration.
Research and Development	Research and Development Costs associated with research and development activities are expensed as incurred and include, but are not limited to, personnel-related expenses, including stock-based compensation expense, materials, laboratory supplies, consulting costs, costs associated with setting up and conducting clinical studies and allocated overhead including rent and utilities.
Advertising and Marketing Cost		Advertising and Marketing Costs Costs associated with advertising and marketing activities are expensed as incurred. Total advertising and marketing costs were approximately $0.4 million and $0.3 million for the three months ended March 31, 2020 and 2019, respectively, and are included in selling, general and administrative expenses in the accompanying condensed statements of operations.
Stock-Based Compensation	Stock-Based Compensation The Company recognizes compensation expense for all stock-based awards to employees and directors based on the grant-date estimated fair values over the requisite service period of the awards (usually the vesting period) on a straight-line basis. The fair value of stock options is determined using the Black-Scholes-Merton (BSM) option pricing model, which requires management to make certain assumptions regarding a number of complex and subjective variables. Equity award forfeitures are recorded as they occur. The BSM option pricing model incorporates various estimates, including the fair value of the Company's common stock, expected volatility, expected term and risk-free interest rates. The weighted-average expected term of options was calculated using the simplified method. This decision was based on the lack of relevant historical data due to the Company's limited historical experience. In addition, due to the Company's limited historical data, the estimated volatility incorporates the historical volatility over the expected term of the award of comparable companies whose share prices are publicly available. The risk-free interest rate for periods within the contractual term of the option is based on the U.S. Treasury yield in effect at the time of grant. The dividend yield was zero, as the Company has never declared or paid dividends and has no plans to do so in the foreseeable future. Upon the effective date of the IPO, the Company began using the closing price of its common stock as the fair value of its common stock on the corresponding date.
Comprehensive Loss	Comprehensive Loss Comprehensive loss is defined as a change in equity of a business enterprise during a period, resulting from transactions from nonowner sources. There have been no items qualifying as other comprehensive loss and, therefore, for all periods presented, the Company's comprehensive loss was the same as its reported net loss.
Net Loss Per Share	Net Loss Per Share Basic net loss per share attributable to common stockholders is calculated by dividing the net loss attributable to common stockholders by the weighted-average number of common shares outstanding during the period. Diluted net loss per share attributable to common stockholders is computed by dividing the net loss attributable to common stockholders by the weighted-average number of common stock equivalents outstanding for the period determined using the treasury-stock and if-converted methods. Potentially dilutive common stock equivalents are comprised of redeemable convertible preferred stock, warrants for the purchase of redeemable convertible preferred and common stock and options outstanding under the Company's stock option plans. For the three months ended March 31, 2020 and 2019, there is no difference in the number of shares used to calculate basic and diluted shares outstanding as the inclusion of the potentially dilutive securities would be antidilutive.
Segment Reporting	Segment Reporting Operating segments are identified as components of an enterprise about which separate discrete financial information is available for evaluation by the chief operating decision-maker in making decisions regarding resource allocation and assessing performance. The Company views its operations as, and manages its business in, one operating segment.
Recent Accounting Pronouncements	Recent Accounting Pronouncements From time to time, new accounting pronouncements are issued by the Financial Accounting Standards Board (FASB), or other standard setting bodies and adopted by the Company as of the specified effective date. Under the Jumpstart Our Business Startups Act of 2012 (JOBS Act), the Company meets the definition of an emerging growth company. The Company has elected to use the extended transition period for complying with new or revised accounting standards pursuant to Section 107(b) of the JOBS Act. Unless otherwise discussed, the impact of recently issued standards that are not yet effective will not have a material impact on the Company's financial position or results of operations upon adoption. In February 2016, the FASB issued Accounting Standards Update (ASU) 2016-02, Leases (Topic 842). The new topic supersedes Topic 840, Leases, and increases transparency and comparability among organizations by recognizing lease assets and lease liabilities on the balance sheet and requires disclosures of key information about leasing arrangements. In July 2018, the FASB issued ASU 2018-10, Codification Improvements to Topic 842, which provides narrow amendments to clarify how to apply certain aspects of the new lease standard, and ASU 2018-11, Leases: Targeted Improvements, which was issued to provide relief to companies from restating comparative periods. Pursuant to this ASU, in the period of adoption the Company will not restate comparative periods presented in its condensed financial statements. The effective date of this guidance for public companies is for reporting periods beginning after December 15, 2018. As an emerging growth company as defined in the JOBS Act, the Company has elected to delay adoption of this ASU until January 1, 2021. Topic 842 mandates a modified retrospective transition method. The Company intends to adopt the new lease standard using a cumulative effect to accumulated deficit and will elect the package of practical expedients, which among other things will allow the Company to carry forward its historical lease classification. The Company is currently evaluating the impact of Topic 842 on its condensed financial statements. Recently Adopted Accounting Standards In August 2018, the FASB issued ASU No. 2018-13, Fair Value Measurement: Disclosure Framework--Changes to the Disclosure Requirements for Fair Value Measurement, which adds and modifies certain disclosure requirements for fair value measurements. Under the new guidance, entities will no longer be required to disclose the amount of and reasons for transfers between Level 1 and Level 2 of the fair value hierarchy, or valuation processes for Level 3 fair value measurements. However, public companies will be required to disclose the range and weighted average of significant unobservable inputs used to develop Level 3 fair value measurements, and related changes in unrealized gains and losses included in other comprehensive income. The narrative description of measurement uncertainty should be applied prospectively for only the most recent interim or annual period presented in the initial fiscal year of adoption. All other amendments should be applied retrospectively to all period presented upon their effective date. This update is effective for annual periods beginning after December 15, 2019, and interim periods within those periods, and early adoption is permitted. The Company adopted this guidance on January 1, 2020, and the adoption did not have a material impact on its condensed financial statements.

Summary Of Significant Accounting Policies - (Tables)

3 Months Ended

Mar. 31, 2020

Accounting Policies [Abstract]

Schedule of Concentration of Risk, by Risk Factor and Significant Payer

For each significant payer and customer, revenue as a percentage of total revenue and accounts receivable as a percentage of total accounts receivable are as follows:


	Revenue
	Three Months Ended March 31,
	2020		2019
Medicare	25	%	26	%
Blue Shield	12	%	13	%
United Healthcare	10	%	11	%
Medicare Advantage	13	%	10	%


	Accounts Receivable
	March 31, 2020		December 31, 2019


United Healthcare	22	%	22	%
Blue Shield	14	%	15	%

Janssen (SIMPONI^®)	*		19	%



*						Less than 10%.

Disaggregation of Revenue

The following table includes the Company's revenues as disaggregated by payer and customer category (in thousands):


	Three Months Ended March 31,
	2020		2019
Revenue:
Healthcare insurers	$	6,062	$	5,461
Government	2,245		2,432
Client	1,082		1,105
Other(1)	195		162
Janssen (SIMPONI^®)	—		100
Total revenue	$	9,584	$	9,260

(1)Includes patient self-pay that is immaterial.

Schedule of Restricted Cash and Cash Equivalents

Cash, cash equivalents and restricted cash presented in the accompanying condensed statements of cash flows consist of the following (in thousands):


	March 31, 2020		December 31, 2019

Cash and cash equivalents	$	68,648	$	72,084
Restricted cash	100		100
	$	68,748	$	72,184

Schedule of Cash and Cash Equivalents

Cash, cash equivalents and restricted cash presented in the accompanying condensed statements of cash flows consist of the following (in thousands):


	March 31, 2020		December 31, 2019

Cash and cash equivalents	$	68,648	$	72,084
Restricted cash	100		100
	$	68,748	$	72,184

Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share

Potentially dilutive securities not included in the calculation of diluted net loss per share because to do so would be anti-dilutive are as follows (in common stock equivalent shares):


	Three Months Ended March 31,
	2020	2019
Redeemable convertible preferred stock	—	5,734,680
Warrants to purchase redeemable convertible preferred stock	—	224,493
Warrants to purchase common stock	436,581	934,789
Common stock options	1,630,014	662,365
Total	2,066,595	7,556,327

Other Financial Information - (Tables)

3 Months Ended

Mar. 31, 2020

Other Financial Information [Abstract]

Prepaid expenses table

Prepaid expenses and other current assets consist of the following (in thousands):


	March 31, 2020		December 31, 2019
Diagnostic testing supplies	$	1,299	$	1,427
Prepaid product royalties	110		123
Prepaid maintenance and insurance contracts	1,651		1,768
Other prepaid assets	24		133
Prepaid and other current assets	$	3,084	$	3,451

Property and equipment

Property and equipment consist of the following (in thousands):


	March 31, 2020		December 31, 2019
Furniture and fixtures	$	32	$	25
Laboratory equipment	2,501		2,228
Computer equipment and software	891		851
Leasehold improvements	424		424
Construction in progress	49		247
Total property and equipment	3,897		3,775
Less: accumulated depreciation and amortization	(2,521)		(2,395)
Property and equipment, net	$	1,376	$	1,380

Accrued liabilities

Accrued liabilities consist of the following (in thousands):


	March 31, 2020		December 31, 2019
Accrued payroll and related expenses	$	2,733	$	2,362

Accrued interest	145		145
Accrued purchases of goods and services	282		319
Accrued royalties	407		727
Accrued clinical study activity	50		40
Capital lease obligations, current portion	241		238
Other accrued liabilities	905		588
Accrued liabilities	$	4,763	$	4,419

Borrowings - (Tables)

3 Months Ended

Mar. 31, 2020

Debt Disclosure [Abstract]

Schedule of Future Minimum Aggregate Payments for Outstanding Borrowings

future minimum aggregate payments, including interest, for outstanding borrowings under the Loan Amendment are as follows (in thousands):


	March 31, 2020
2020 (remaining)	$	1,299
2021	1,755
2022	2,996
2023	15,619
2024	14,280
Total	35,949
Less:
Unamortized debt discount and issuance costs	(367)
Interest	(9,532)
Total borrowings, net of discounts and debt issuance costs	$	26,050

Fair Value Measures and Disclosures (Tables)

3 Months Ended

Mar. 31, 2020

Fair Value Disclosures [Abstract]

Schedule of Fair Value, Financial Instrument Measured on a Recurring Basis

The following table sets forth the Company's financial instruments that were measured at fair value on a recurring basis within the fair value hierarchy (in thousands):


	March 31, 2020
	Total		Level 1		Level 2		Level 3
Assets:
Money market funds	$	67,431	$	67,431	$	—	$	—


	December 31, 2019
	Total		Level 1		Level 2		Level 3
Assets:
Money market funds	$	70,760	$	70,760	$	—	$	—

Stock Option Plan (Tables)

3 Months Ended

Mar. 31, 2020

Share-based Payment Arrangement [Abstract]

Schedule of Stock Option Activity

Activity under the Company's stock option plans is set forth below:


	Number of Options	Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Term (Years)	Aggregate Intrinsic Value
Outstanding, December 31, 2019	1,375,542	$	8.33	9.16	$	23,654
Granted	514,131	$	19.51
Exercised	(43,700)	$	0.26
Forfeited	(215,542)	$	9.73
Expired	(417)	$	19.04
Outstanding, March 31, 2020	1,630,014	$	11.88	9.22	$	9,324
Vested and expected to vest, March 31, 2020	1,630,014	$	11.88	9.22	$	9,324
Options exercisable, March 31, 2020	199,168	$	3.77	7.90	$	2,740

Schedule of Fair Value Assumptions, Stock Options

The fair value of employee stock options was estimated using the following assumptions to determine the fair value of stock options granted:


	Three Months Ended March 31,
	2020	2019
Expected volatility	47%-50%	59%
Risk-free interest rate	0.6%-1.7%	2.6%
Dividend yield	—	—
Expected term (in years)	6.08	6.08

Schedule of Non-cash Stock-based Compensation Expense

Total non-cash stock-based compensation expense recorded related to options granted in the condensed statement of operations is as follows (in thousands):


	Three Months Ended March 31,
	2020		2019
Cost of revenue	$	6	$	1
Selling, general and administrative	422		10
Research and development	3		1
Total	$	431	$	12

Organization - (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Cash and cash equivalents	$ 68,648	$ 72,084
Accumulated deficit	$ 170,165	$ 164,602

Summary Of Significant Accounting Policies - Narrative (Details) - USD ($)	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2016
New Accounting Pronouncement, Early Adoption [Line Items]
Restricted cash	$ 100,000		$ 100,000
Revenue	9,584,000	$ 9,260,000
Advertising Expense	$ 400,000	$ 300,000
Minimum
New Accounting Pronouncement, Early Adoption [Line Items]
Joint venture, quarterly promotion fee				$ 750
Maximum
New Accounting Pronouncement, Early Adoption [Line Items]
Joint venture, quarterly promotion fee				$ 1,250
Revenue Benchmark \| Supplier Concentration Risk
New Accounting Pronouncement, Early Adoption [Line Items]
Percent of total revenue	96.00%	94.00%
Janssen (SIMPONI)
New Accounting Pronouncement, Early Adoption [Line Items]
Revenue	$ 0	$ 100,000
Shipping and Handling
New Accounting Pronouncement, Early Adoption [Line Items]
Cost of revenue	$ 400,000	$ 400,000
Other assets
New Accounting Pronouncement, Early Adoption [Line Items]
Restricted cash					$ 100,000

Summary Of Significant Accounting Policeies - Revenue by Major Payers (Details)	3 Months Ended		12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Medicare \| Revenue Benchmark \| Customer Concentration Risk
Disaggregation of Revenue [Line Items]
Percent of total revenue	25.00%	26.00%
Blue Shield \| Revenue Benchmark \| Customer Concentration Risk
Disaggregation of Revenue [Line Items]
Percent of total revenue	12.00%	13.00%
Blue Shield \| Accounts Receivable \| Customer Concentration Risk
Disaggregation of Revenue [Line Items]
Percent of total revenue	14.00%		15.00%
United Healthcare \| Revenue Benchmark \| Customer Concentration Risk
Disaggregation of Revenue [Line Items]
Percent of total revenue	10.00%	11.00%
United Healthcare \| Accounts Receivable \| Customer Concentration Risk
Disaggregation of Revenue [Line Items]
Percent of total revenue	22.00%		22.00%
Medicare Advantage \| Revenue Benchmark \| Customer Concentration Risk
Disaggregation of Revenue [Line Items]
Percent of total revenue	13.00%	10.00%
Janssen (SIMPONI) \| Accounts Receivable \| Customer Concentration Risk
Disaggregation of Revenue [Line Items]
Percent of total revenue			19.00%
AVISE CTD Test \| Revenue Benchmark \| Product Concentration Risk
Disaggregation of Revenue [Line Items]
Percent of total revenue	83.00%	85.00%

Summary Of Significant Accounting Policies - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Disaggregation of Revenue [Line Items]
Revenue	$ 9,584	$ 9,260
Healthcare Insurers
Disaggregation of Revenue [Line Items]
Revenue	6,062	5,461
Government
Disaggregation of Revenue [Line Items]
Revenue	2,245	2,432
Client
Disaggregation of Revenue [Line Items]
Revenue	1,082	1,105
Other
Disaggregation of Revenue [Line Items]
Revenue	195	162
Janssen (SIMPONI)
Disaggregation of Revenue [Line Items]
Revenue	$ 0	$ 100

Summary Of Significant Accounting Policies - Cash, cash equivalents and restricted cash (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019	Mar. 31, 2019	Dec. 31, 2018
Accounting Policies [Abstract]
Cash and cash equivalents	$ 68,648	$ 72,084
Restricted cash	100	100
Total Cash, Cash Equivalents and Restricted Cash	$ 68,748	$ 72,184	$ 14,427	$ 13,264

Summary Of Significant Accounting Policies - Securities (Details) - shares	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Class of Stock [Line Items]
Anti-dilutive securities excluded from computation	2,066,595	7,556,327
Redeemable Preferred Stock [Member]
Class of Stock [Line Items]
Anti-dilutive securities excluded from computation	0	5,734,680
Warrants to purchase redeemable convertible preferred stock
Class of Stock [Line Items]
Anti-dilutive securities excluded from computation	0	224,493
Warrants to purchase common stock
Class of Stock [Line Items]
Anti-dilutive securities excluded from computation	436,581	934,789
Common stock options
Class of Stock [Line Items]
Anti-dilutive securities excluded from computation	1,630,014	662,365

Other Financial Information - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Property, Plant and Equipment [Line Items]
Depreciation and amortization	$ 100	$ 200
Property and equipment, gross	3,897		$ 3,775
Assets under capital lease
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 1,100		$ 800

Other Financial Information - Prepaid expenses (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Other Financial Information [Abstract]
Other current assets	$ 1,299	$ 1,427
Prepaid product royalties	110	123
Prepaid maintenance and insurance contracts	1,651	1,768
Other prepaid assets	24	133
Prepaid and other current assets	$ 3,084	$ 3,451

Other Financial Information - Property and equipment (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 3,897	$ 3,775
Less: accumulated depreciation and amortization	(2,521)	(2,395)
Property and equipment, net	1,376	1,380
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Total property and equipment	32	25
Laboratory equipment
Property, Plant and Equipment [Line Items]
Total property and equipment	2,501	2,228
Computer equipment and software
Property, Plant and Equipment [Line Items]
Total property and equipment	891	851
Leasehold improvements
Property, Plant and Equipment [Line Items]
Total property and equipment	424	424
Construction in progress
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 49	$ 247

Other Financial Information - Accrued liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Other Financial Information [Abstract]
Accrued payroll and related expenses	$ 2,733	$ 2,362
Accrued interest	145	145
Accrued purchases of goods and services	282	319
Accrued royalties	407	727
Accrued clinical study activity	50	40
Capital lease obligations, current portion	241	238
Other accrued liabilities	905	588
Accrued liabilities	$ 4,763	$ 4,419

Borrowings - Narrative (Details) - USD ($) $ in Thousands		1 Months Ended	3 Months Ended
Borrowings - Narrative (Details) - USD ($) $ in Thousands	Dec. 07, 2018	Sep. 30, 2017	Mar. 31, 2020	Mar. 31, 2019	Nov. 30, 2019
Loan payable \| Capital Royalty Partners II LP
Debt Instrument [Line Items]
Loan repayment		$ 17,800
2017 Term loan \| Loan payable \| Innovatus Life Sciences Lending Fund
Debt Instrument [Line Items]
Term loan borrowings	$ 5,000	$ 20,000
Term loan, interest rate					8.50%
Term loan, paid in-kind, interest rate					2.00%
Term loan, effective interest rate					10.00%
Term loan, fee incurred upon payment of final installment					$ 1,000
Term loan, prepayment premium percentage					3.00%
Term loan, annual reduction in prepayment penalty percentage					1.00%
Term loan covenant, minimum unrestricted cash balance					$ 2,000
Term loan covenant, increase to interest rate					4.00%
2017 Term loan \| Paid in-kind note \| Innovatus Life Sciences Lending Fund
Debt Instrument [Line Items]
Term loan, paid in-kind loans issued			$ 100	$ 200

Borrowings - Future minimum payments (Details) $ in Thousands	Mar. 31, 2020 USD ($)
Debt Disclosure [Abstract]
2020 (remaining)	$ 1,299
2021	1,755
2022	2,996
2023	15,619
2024	14,280
Total	35,949
Unamortized debt discount and issuance costs	367
Interest	9,532
Total borrowings, net of discounts and debt issuance costs	$ 26,050

Commitment and Contingencies - Narrative (Details) - USD ($)	3 Months Ended		12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019	Dec. 31, 2018
Loss Contingencies [Line Items]
Rent expense	$ 100,000	$ 100,000
Minimum annual purchase commitment			$ 4,200,000
Purchase commitment, term				3 years
Minimum \| Licensing Agreements
Loss Contingencies [Line Items]
Royalty obligation, percent of net sales	3.00%
Maximum
Loss Contingencies [Line Items]
Royalty obligation, percent of net sales	20.00%
Prometheus Laboratories
Loss Contingencies [Line Items]
Remaining milestone obligation	$ 2,000,000.0
Remaining milestone obligation, fair value	0		$ 0
Advance royalties payment	$ 100,000
Prometheus Laboratories \| Minimum
Loss Contingencies [Line Items]
Royalty obligation, percent of net sales	2.50%
Prometheus Laboratories \| Maximum
Loss Contingencies [Line Items]
Royalty obligation, percent of net sales	7.50%
Future minimum royalty commitment	$ 4,200,000
Office and Laboratory
Loss Contingencies [Line Items]
Operating lease, renewal term	5 years
Office
Loss Contingencies [Line Items]
Operating lease, renewal term	5 years

Fair Value Measurements - Fair value measurement (Details) - Recurring - Money market funds - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Assets:
Money market funds	$ 67,431	$ 70,760
Level 1
Assets:
Money market funds	67,431	70,760
Level 2
Assets:
Money market funds	0	0
Level 3
Assets:
Money market funds	$ 0	$ 0

Redeemable Convertible Preferred Stock (Details) - $ / shares		1 Months Ended	3 Months Ended
	Sep. 23, 2019	Jan. 31, 2019	Mar. 31, 2019
Common Stock \| IPO
Temporary Equity [Line Items]
Stock issued upon conversion of redeemable convertible preferred shares (in shares)	7,816,643
Series G redeemable convertible preferred stock
Temporary Equity [Line Items]
Sale of temporary equity, price per share (in dollars per share)		$ 0.078	$ 0.078

Stockholders' Equity (Details)	3 Months Ended
Stockholders' Equity (Details)	Mar. 31, 2020 $ / shares shares
Subsidiary, Sale of Stock [Line Items]
Warrants issued to purchase redeemable convertible preferred stock	436,581
Number of warrants exercised	24,692
Number of common shares to be called upon exercise of warrants	22,366
Warrant expiration January 19, 2026
Subsidiary, Sale of Stock [Line Items]
Warrants issued to purchase redeemable convertible preferred stock	259,975
Exercise Price \| $ / shares	$ 1.84
Warrant expiration March 31, 2026
Subsidiary, Sale of Stock [Line Items]
Warrants issued to purchase redeemable convertible preferred stock	71,753
Exercise Price \| $ / shares	$ 1.84
Warrant expiration April 1, 2026
Subsidiary, Sale of Stock [Line Items]
Warrants issued to purchase redeemable convertible preferred stock	131
Exercise Price \| $ / shares	$ 1.84
Warrant expiration September 8, 2024
Subsidiary, Sale of Stock [Line Items]
Warrants issued to purchase redeemable convertible preferred stock	83,778
Exercise Price \| $ / shares	$ 14.32
Warrant expiration December 7, 2025
Subsidiary, Sale of Stock [Line Items]
Warrants issued to purchase redeemable convertible preferred stock	20,944
Exercise Price \| $ / shares	$ 14.32

Stock Option Plan - Narrative (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Sep. 30, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options, unrecognized compensation cost	$ 8.7
Stock options, cost not yet recognized, remaining weighted average vesting period	3 years 3 months 18 days
Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options, expiration period	10 years
Stock options, vesting period	4 years
2019 Incentive Award Plan \| Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares reserved for issuance under Stock Option Plan		2,011,832
Annual percentage increase in shares available for issuance under the Plan	4.00%
Shares that remain available for future awards	1,488,919

Stock Option Plan - Stock Option Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2020	Dec. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Outstanding, December 31, 2019 (in shares)	1,375,542
Granted (in shares)	514,131
Exercised (in shares)	(43,700)
Forfeited (in shares)	(215,542)
Expired (in shares)	(417)
Outstanding, March 31, 2020 (in shares)	1,630,014	1,375,542
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract]
Outstanding, December 31, 2019, Weighted Average Exercise Price (in dollars per share)	$ 8.33
Granted, Weighted Average Exercise Price (in dollars per share)	19.51
Exercised, Weighted Average Exercise Price (in dollars per share)	0.26
Forfeited, Weighted Average Exercise Price (in dollars per share)	9.73
Expired, Weighted Average Exercise Price (in dollars per share)	19.04
Outstanding, March 31, 2020, Weighted Average Exercise Price (in dollars per share)	$ 11.88	$ 8.33
Stock Options, Additional Disclosures [Abstract]
Outstanding, Weighted Average Remaining Contractual Term	9 years 2 months 19 days	9 years 1 month 28 days
Vested and expected to vest, Weighted Average Remaining Contractual Term	9 years 2 months 19 days
Options exercisable, Weighted Average Remaining Contractual Term	7 years 10 months 24 days
Outstanding, Aggregate Intrinsic Value	$ 9,324	$ 23,654
Vested and expected to vest, Aggregate Intrinsic Value	9,324
Options exercisable, Aggregate Intrinsic Value	$ 2,740
Vested and expected to vest, March 31, 2020 (in shares)	1,630,014
Vested and expected to vest, March 31, 2020, Weighted Average Exercise Price (in dollars per share)	$ 11.88
Options exercisable, March 31, 2020 (in Shares)	199,168
Options exercised, March 31, 2020, Weighted Average Exercise Price (in dollars per share)	$ 3.77

Stock Option Plan - Fair Value Assumptions (Details)	3 Months Ended
Stock Option Plan - Fair Value Assumptions (Details)	Mar. 31, 2020	Mar. 31, 2019
Share-based Payment Arrangement [Abstract]
Expected volatility rate, minimum	47.00%
Expected volatility rate, maximum	50.00%
Expected volatility		59.00%
Risk-free interest rate, minimum	0.60%
Risk-free interest rate, maximum	1.70%
Risk-free interest rate		2.60%
Dividend yield	0.00%	0.00%
Expected term (in years)	6 years 29 days	6 years 29 days

Stock Option Plan - Stock-Based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 431	$ 12
Cost of revenue
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	6	1
Selling, general and administrative
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	422	10
Research and development
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 3	$ 1

Covid-19 (Details) - USD ($) $ in Thousands	1 Months Ended		3 Months Ended
Covid-19 (Details) - USD ($) $ in Thousands	Apr. 30, 2020	Mar. 31, 2020	Mar. 31, 2020	Mar. 31, 2019
Restructuring Cost and Reserve [Line Items]
AVISE CTD test volume, percentage		12.00%
Stock-based compensation expense reversal			$ (431)	$ (12)
Coronavirus, Aid, Relief, And Economic Securities (CARES) Act, deferred tax assets, valuation allowance		$ 100	100
Coronavirus, Aid, Relief, And Economic Securities (CARES) Act, deferred tax assets, income tax benefit			100
Share-based Payment Arrangement, Employee
Restructuring Cost and Reserve [Line Items]
Stock-based compensation expense reversal			100
One-time Termination Benefits
Restructuring Cost and Reserve [Line Items]
Restructuring charges			$ 300
Subsequent Event
Restructuring Cost and Reserve [Line Items]
AVISE CTD test volume, percentage	56.00%

Subsequent Events - Narrative (Details) $ in Millions	Apr. 10, 2020 USD ($)
Subsequent Event
Subsequent Event [Line Items]
Coronavirus, Aid, Relief, and Economic Securities (CARES) Act, proceeds from loan	$ 0.7