Adaptive Biotechnologies (ADPT) 10-Q 10 Nov 20 2020 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2020	Oct. 31, 2020
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2020
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q3
Trading Symbol	ADPT
Entity Registrant Name	ADAPTIVE BIOTECHNOLOGIES CORPORATION
Entity Central Index Key	0001478320
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	true
Entity Ex Transition Period	false
Title of 12(b) Security	Common stock, par value $0.0001 per share
Security Exchange Name	NASDAQ
Entity Common Stock, Shares Outstanding		136,772,417
Entity Current Reporting Status	Yes
Entity Shell Company	false
Entity Interactive Data Current	Yes
Entity File Number	001-38957
Entity Tax Identification Number	27-0907024
Entity Address, Address Line One	1551 Eastlake Avenue East
Entity Address, Address Line Two	Suite 200
Entity Address, City or Town	Seattle
Entity Address, State or Province	WA
Entity Address, Postal Zip Code	98102
City Area Code	(206)
Local Phone Number	659-0067
Document Quarterly Report	true
Document Transition Report	false
Entity Incorporation, State or Country Code	WA

Condensed Balance Sheets (Unaud

Condensed Balance Sheets (Unaudited) - USD ($)	Sep. 30, 2020	Dec. 31, 2019
Current assets
Cash and cash equivalents	$ 497,076,000	$ 96,576,000
Short-term marketable securities (amortized cost of $336,840 and $479,791, respectively)	338,004,000	480,290,000
Accounts receivable, net	11,858,000	12,676,000
Inventory	10,736,000	9,069,000
Prepaid expenses and other current assets	19,684,000	14,079,000
Total current assets	877,358,000	612,690,000
Long-term assets
Property and equipment, net	31,156,000	60,355,000
Operating lease right-of-use assets	37,733,000
Long-term marketable securities (amortized cost of $16,203 and $105,263, respectively)	16,466,000	105,435,000
Restricted cash	2,138,000	2,138,000
Intangible assets, net	10,653,000	11,928,000
Goodwill	118,972,000	118,972,000
Other assets	997,000	784,000
Total assets	1,095,473,000	912,302,000
Current liabilities
Accounts payable	5,412,000	4,453,000
Accrued liabilities	5,346,000	4,371,000
Accrued compensation and benefits	7,913,000	8,124,000
Current portion of deferred rent		371,000
Current operating lease liabilities	3,969,000
Current deferred revenue	78,192,000	60,994,000
Total current liabilities	100,832,000	78,313,000
Long-term liabilities
Deferred rent liability, less current portion		6,918,000
Operating lease liabilities, less current portion	42,366,000
Financing obligation		36,607,000
Deferred revenue, less current portion	174,853,000	219,332,000
Other long-term liabilities	2,375,000	93,000
Total liabilities	320,426,000	341,263,000
Commitments and contingencies (Note 9)
Shareholders’ equity
Preferred stock: $0.0001 par value, 10,000,000 shares authorized at September 30, 2020 and December 31, 2019; no shares issued and outstanding at September 30, 2020 and December 31, 2019
Common stock: $0.0001 par value, 340,000,000 shares authorized at September 30, 2020 and December 31, 2019; 136,392,256 and 125,238,142 shares issued and outstanding at September 30, 2020 and December 31, 2019, respectively	13,000	12,000
Additional paid-in capital	1,240,649,000	935,834,000
Accumulated other comprehensive gain	1,427,000	671,000
Accumulated deficit	(467,042,000)	(365,478,000)
Total shareholders’ equity	775,047,000	571,039,000
Total liabilities and shareholders’ equity	$ 1,095,473,000	$ 912,302,000

Condensed Balance Sheets (Una_2

Condensed Balance Sheets (Unaudited) (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Statement Of Financial Position [Abstract]
Amortized cost of short-term marketable securities	$ 336,840	$ 479,791
Amortized cost of long-term marketable securities	$ 16,203	$ 105,263
Preferred stock par value	$ 0.0001	$ 0.0001
Preferred stock authorized	10,000,000	10,000,000
Preferred stock issued	0	0
Preferred stock outstanding	0	0
Common stock par value	$ 0.0001	$ 0.0001
Common stock authorized	340,000,000	340,000,000
Common stock issued	136,392,256	125,238,142
Common stock outstanding	136,392,256	125,238,142

Condensed Statements of Operati

Condensed Statements of Operations (Unaudited) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Revenue
Total revenue	$ 26,299,000	$ 26,058,000	$ 68,197,000	$ 60,862,000
Operating expenses
Cost of revenue	6,053,000	5,601,000	16,308,000	16,323,000
Research and development	30,314,000	20,506,000	80,241,000	49,516,000
Sales and marketing	14,474,000	9,099,000	42,813,000	25,813,000
General and administrative	12,079,000	8,477,000	36,138,000	22,143,000
Amortization of intangible assets	428,000	428,000	1,275,000	1,270,000
Total operating expenses	63,348,000	44,111,000	176,775,000	115,065,000
Loss from operations	(37,049,000)	(18,053,000)	(108,578,000)	(54,203,000)
Interest and other income, net	1,018,000	4,103,000	5,805,000	6,208,000
Income tax (expense) benefit	(688,000)		1,116,000
Net loss	(36,719,000)	(13,950,000)	(101,657,000)	(47,995,000)
Fair value adjustment to Series E-1 convertible preferred stock options				(964,000)
Net loss attributable to common shareholders	$ (36,719,000)	$ (13,950,000)	$ (101,657,000)	$ (48,959,000)
Net loss per share attributable to common shareholders, basic and diluted	$ (0.27)	$ (0.11)	$ (0.79)	$ (0.97)
Weighted-average shares used in computing net loss per share attributable to common shareholders, basic and diluted	134,372,026	124,285,686	129,289,948	50,552,389
Sequencing Revenue
Revenue
Total revenue	$ 11,276,000	$ 11,683,000	$ 28,730,000	$ 29,631,000
Development Revenue
Revenue
Total revenue	$ 15,023,000	$ 14,375,000	$ 39,467,000	$ 31,231,000

Condensed Statements of Compreh

Condensed Statements of Comprehensive Loss (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Statement Of Financial Position [Abstract]
Net loss	$ (36,719)	$ (13,950)	$ (101,657)	$ (47,995)
Change in unrealized (loss) gain on investments	(726)	190	756	679
Comprehensive loss	$ (37,445)	$ (13,760)	$ (100,901)	$ (47,316)

Condensed Statements of Convert

Condensed Statements of Convertible Preferred Stock and Shareholders' (Deficit) Equity (Unaudited) - USD ($) $ in Thousands	Total	Cumulative Effect, Period of Adoption, Adjustment	Convertible Preferred Stock	Common Stock	Additional Paid In Capital	Accumulated Other Comprehensive (Loss) Gain	Accumulated Deficit	Accumulated DeficitCumulative Effect, Period of Adoption, Adjustment
Beginning Balance at Dec. 31, 2018	$ (258,112)			$ 1	$ 37,902	$ (107)	$ (295,908)
Beginning Balance, Shares at Dec. 31, 2018				12,841,536
Convertible preferred stock, Beginning Balance at Dec. 31, 2018			$ 560,858
Convertible preferred stock, Beginning Balance, Shares at Dec. 31, 2018			92,790,094
Proceeds from initial public offering/ issuance of common stock upon public offering, net of underwriters' discounts and commissions and net offering costs payable by us	320,850			$ 2	320,848
Proceeds from initial public offering/ issuance of common stock upon public offering, net of underwriters' discounts and commissions and net offering costs payable by us, Shares				17,250,000
Initial public offering costs	(4,986)				(4,986)
Conversion of convertible preferred stock to common stock	561,931		$ (561,931)	$ 9	561,922
Conversion of convertible preferred stock to common stock, Shares			(93,039,737)	93,039,737
Conversion of convertible preferred stock warrant to common stock warrant	2,602				2,602
Issuance of common stock upon exercise of common stock warrants	9				9
Issuance of common stock upon exercise of common stock warrants, Shares				54,792
Issuance of common stock for cash upon exercise of stock options	2,198				2,198
Issuance of common stock for cash upon exercise of stock options, Shares				1,130,015
Issuance of Series E-1 convertible preferred stock for cash upon exercise of Series E-1 convertible preferred stock options at fair value			$ 109
Issuance of Series E-1 convertible preferred stock for cash upon exercise of Series E-1 convertible preferred stock options at fair value, Shares			249,643
Change in redemption value for vested Series E-1 convertible preferred stock options	(964)		$ 964				(964)
Common stock option and restricted stock unit share- based compensation	9,713				9,713
Other comprehensive income (loss)	679					679
Net loss	(47,995)						(47,995)
Ending Balance at Sep. 30, 2019	585,925			$ 12	930,208	572	(344,867)
Ending Balance, Shares at Sep. 30, 2019				124,316,080
Beginning Balance at Jun. 30, 2019	(284,374)			$ 1	46,160	382	(330,917)
Beginning Balance, Shares at Jun. 30, 2019				13,725,381
Convertible preferred stock, Beginning Balance at Jun. 30, 2019			$ 561,931
Convertible preferred stock, Beginning Balance, Shares at Jun. 30, 2019			93,039,737
Proceeds from initial public offering/ issuance of common stock upon public offering, net of underwriters' discounts and commissions and net offering costs payable by us	320,850			$ 2	320,848
Proceeds from initial public offering/ issuance of common stock upon public offering, net of underwriters' discounts and commissions and net offering costs payable by us, Shares				17,250,000
Initial public offering costs	(4,986)				(4,986)
Conversion of convertible preferred stock to common stock	561,931		$ (561,931)	$ 9	561,922
Conversion of convertible preferred stock to common stock, Shares			(93,039,737)	93,039,737
Conversion of convertible preferred stock warrant to common stock warrant	2,602				2,602
Issuance of common stock upon exercise of common stock warrants	9				9
Issuance of common stock upon exercise of common stock warrants, Shares				54,792
Issuance of common stock for cash upon exercise of stock options	318				318
Issuance of common stock for cash upon exercise of stock options, Shares				246,170
Common stock option and restricted stock unit share- based compensation	3,335				3,335
Other comprehensive income (loss)	190					190
Net loss	(13,950)						(13,950)
Ending Balance at Sep. 30, 2019	585,925			$ 12	930,208	572	(344,867)
Ending Balance, Shares at Sep. 30, 2019				124,316,080
Beginning Balance at Dec. 31, 2019	$ 571,039	$ 93		$ 12	935,834	671	(365,478)	$ 93
Beginning Balance, Shares at Dec. 31, 2019				125,238,142
Accounting Standards Update [Extensible List]	us-gaap:AccountingStandardsUpdate201602Member
Proceeds from initial public offering/ issuance of common stock upon public offering, net of underwriters' discounts and commissions and net offering costs payable by us	$ 271,839			$ 1	271,838
Proceeds from initial public offering/ issuance of common stock upon public offering, net of underwriters' discounts and commissions and net offering costs payable by us, Shares				7,200,000
Issuance of common stock for cash upon exercise of stock options	$ 15,459				15,459
Issuance of common stock for cash upon exercise of stock options, Shares	3,949,614			3,949,614
Vesting of restricted stock units				4,500
Common stock option and restricted stock unit share- based compensation	$ 17,518				17,518
Other comprehensive income (loss)	756					756
Net loss	(101,657)						(101,657)
Convertible preferred stock, Ending Balance, Shares at Sep. 30, 2020			0
Ending Balance at Sep. 30, 2020	775,047			$ 13	1,240,649	1,427	(467,042)
Ending Balance, Shares at Sep. 30, 2020				136,392,256
Beginning Balance at Jun. 30, 2020	529,939			$ 12	958,097	2,153	(430,323)
Beginning Balance, Shares at Jun. 30, 2020				128,233,842
Proceeds from initial public offering/ issuance of common stock upon public offering, net of underwriters' discounts and commissions and net offering costs payable by us	271,839			$ 1	271,838
Proceeds from initial public offering/ issuance of common stock upon public offering, net of underwriters' discounts and commissions and net offering costs payable by us, Shares				7,200,000
Issuance of common stock for cash upon exercise of stock options	4,244				4,244
Issuance of common stock for cash upon exercise of stock options, Shares				958,414
Common stock option and restricted stock unit share- based compensation	6,470				6,470
Other comprehensive income (loss)	(726)					(726)
Net loss	(36,719)						(36,719)
Convertible preferred stock, Ending Balance, Shares at Sep. 30, 2020			0
Ending Balance at Sep. 30, 2020	$ 775,047			$ 13	$ 1,240,649	$ 1,427	$ (467,042)
Ending Balance, Shares at Sep. 30, 2020				136,392,256

Condensed Statements of Cash Fl

Condensed Statements of Cash Flows (Unaudited) - USD ($)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Operating activities
Net loss			$ (101,657,000)	$ (47,995,000)
Adjustments to reconcile net loss to net cash (used in) provided by operating activities:
Depreciation expense			4,845,000	4,446,000
Noncash lease expense			2,217,000
Share-based compensation expense			17,518,000	9,713,000
Intangible assets amortization	$ 428,000	$ 428,000	1,275,000	1,270,000
Investment amortization			(484,000)	(3,533,000)
Fair value adjustment of convertible preferred stock warrant				2,266,000
Benefit from income tax	688,000		(1,116,000)		$ 0
Other			62,000	(80,000)
Changes in operating assets and liabilities:
Accounts receivable, net			802,000	(4,398,000)
Inventory			(1,667,000)	(829,000)
Prepaid expenses and other current assets			(3,886,000)	(6,840,000)
Accounts payable and accrued liabilities			30,000	3,131,000
Deferred rent				(628,000)
Operating lease liabilities			(282,000)
Deferred revenue			(27,281,000)	276,209,000
Other			(215,000)	(537,000)
Net cash (used in) provided by operating activities			(109,839,000)	232,195,000
Investing activities
Purchases of property and equipment			(9,433,000)	(8,784,000)
Purchases of marketable securities			(299,786,000)	(772,093,000)
Proceeds from sales and maturities of marketable securities			532,224,000	252,500,000
Net cash provided by (used in) investing activities			223,005,000	(528,377,000)
Financing activities
Proceeds from exercise of stock options			15,495,000	2,307,000
Proceeds from public offering of common stock, net of underwriting discounts and commissions			272,160,000	320,850,000
Payment of public offering costs, net			(321,000)	(4,986,000)
Proceeds from issuance of common stock upon the exercise of a common stock warrant				9,000
Other				(10,000)
Net cash provided by financing activities			287,334,000	318,170,000
Net increase in cash, cash equivalents and restricted cash			400,500,000	21,988,000
Cash, cash equivalents and restricted cash at beginning of year			98,714,000	55,091,000	55,091,000
Cash, cash equivalents and restricted cash at end of period	$ 499,214,000	$ 77,079,000	499,214,000	77,079,000	$ 98,714,000
Noncash investing and financing activities
Purchases of equipment included in accounts payable and accrued liabilities			3,582,000	498,000
Conversion of convertible preferred stock to common stock upon closing of initial public offering				561,931,000
Conversion of convertible preferred stock warrant to common stock warrant upon closing of initial public offering				$ 2,602,000
Derecognition of lease financing arrangements upon adoption of guidance on accounting for leases			$ 36,607,000

Organization and Description of

Organization and Description of Business	9 Months Ended
	Sep. 30, 2020
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Organization and Description of Business	1. Organization Adaptive Biotechnologies Corporation (“we,” “us” or “our”) is a commercial-stage company advancing the field of immune-driven medicine by harnessing the inherent biology of the adaptive immune system to transform the diagnosis and treatment of disease. We believe the adaptive immune system is nature’s most finely tuned diagnostic and therapeutic for most diseases, but the inability to decode it has prevented the medical community from fully leveraging its capabilities. Our immune medicine platform is the foundation for our expanding suite of products and services. The cornerstone of our immune medicine platform and core immunosequencing product, immunoSEQ, serves as our underlying research and development engine and generates revenue from academic and biopharmaceutical customers. Our first clinical diagnostic product, clonoSEQ, is the first test authorized by the Food and Drug Administration (“FDA”) for the detection and monitoring of minimal residual disease (“MRD”) in patients with select blood cancers. We were incorporated in the State of Washington on September 8, 2009 under the name Adaptive TCR Corporation. On December 21, 2011, we changed our name to Adaptive Biotechnologies Corporation. We are headquartered in Seattle, Washington. Initial Public Offering Our registration statement on Form S-1 related to our initial public offering was declared effective on June 26, 2019 and our common stock began trading on the Nasdaq Global Select Market on June 27, 2019. On July 1, 2019, we completed our initial public offering in which we issued and sold 17,250,000 shares of common stock, including shares issued upon the exercise in full of the underwriters’ over-allotment option, at a public offering price of $20.00 per share. Follow-On Offering In July 2020, we completed an underwritten public offering of our common stock in which we issued and sold 7,200,000 shares of common stock at a public offering price of $40.00 per share, including shares issued upon the exercise in full of the underwriters’ over-allotment option. We received $271.8 million in net proceeds, after deducting underwriting discounts and net offering expenses payable by us.

Significant Accounting Policies

Significant Accounting Policies	9 Months Ended
	Sep. 30, 2020
Accounting Policies [Abstract]
Significant Accounting Policies	2. Significant Basis The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America (“GAAP”) requires management to make certain estimates, judgments and assumptions that affect the reported amounts of assets and liabilities and the related disclosures at the date of the financial statements, as well as the reported amounts of revenues and expenses during the periods presented. We base our estimates on historical experience and other relevant assumptions that we believe to be reasonable under the circumstances. Estimates are used in several areas including, but not limited to, estimates of progress to date for certain performance obligations and the transaction price for certain contracts with customers, share-based compensation, including the fair value of stock, the provision for income taxes, including related reserves, and goodwill, among others. These estimates generally involve complex issues and require judgments, involve the analysis of historical results and prediction of future trends, can require extended periods of time to resolve and are subject to change from period to period. Actual results may differ materially from management’s estimates. Unaudited Interim Condensed Financial Statements In our opinion, the accompanying unaudited condensed financial statements have been prepared in accordance with GAAP for interim financial information. These unaudited condensed financial statements include all adjustments necessary to fairly state the financial position and the results of our operations and cash flows for interim periods in accordance with GAAP. All such adjustments are of a normal, recurring nature. Interim-period results are not necessarily indicative of results of operations or cash flows for a full year or any subsequent interim period. The accompanying unaudited condensed financial statements should be read in conjunction with our audited financial statements and notes included in our Annual Report on Form 10-K for the year ended December 31, 2019 filed with the SEC on February 26, 2020. Reclassifications In the accompanying unaudited condensed statements of cash flows, certain prior year amounts have been reclassified to conform to the current period presentation. Specifically, the gain on equipment disposals line item and other line item were previously separately stated and are now presented together in the other line item. There was no change to net cash provided by operating activities as a result of the reclassification. Restricted Cash We are required to maintain certain balances under lease arrangements for our property and facility leases. We had restricted cash of $2.1 million as of September 30, 2020 and December 31, 2019. Leases We determine if an arrangement contains a lease at inception. We have operating lease agreements for the laboratory and office facilities that we occupy, as well as server space. Operating lease right-of-use (“ROU”) assets and operating lease liabilities are recognized at the date the underlying asset becomes available for our use and are based on the present value of the future minimum lease payments over the lease term. ROU assets also include any initial direct costs incurred and any lease payments made at or before the lease commencement date, less lease incentives received. As our leases generally do not provide an implicit interest rate, the present value of our future minimum lease payments is determined using our incremental borrowing rate. This rate is an estimate of the collateralized borrowing rate we would incur on our future lease payments over a similar term and is based on the information available to us at the lease commencement date, or as of January 1, 2020 for commenced leases that existed as of our adoption of the new lease standard, discussed in more detail below. Certain of our leases contain options to extend or terminate the lease; lease terms are adjusted for these options only when it is reasonably certain we will exercise these options. Our lease agreements do not contain residual value guarantees or covenants. We have made a policy election regarding our real estate leases not to separate nonlease components from lease components, to the extent they are fixed. Nonlease components that are not fixed are expensed as incurred as variable lease expense. Our leases for laboratory and office facilities typically include variable nonlease components, such as common-area maintenance costs. We have also elected not to record on the balance sheet a lease that has a lease term of twelve months or less and does not contain a purchase option that we are reasonably certain to exercise. Lease expense is recognized on a straight-line basis over the terms of the leases. Incentives granted under our facilities leases, including rent holidays, are recognized as adjustments to lease expense on a straight-line basis over the terms of the leases. Concentrations We are subject to a concentration of risk from a limited number of suppliers, or in some cases, single suppliers for some of our laboratory instruments and materials. This risk is managed by targeting a quantity of surplus stock. Cash, cash equivalents and marketable securities are financial instruments that potentially subject us to concentrations of credit risk. We invest in money market funds, United States (“U.S.”) government debt securities, U.S. government agency securities, commercial paper and corporate bonds with high-quality accredited financial institutions. Significant customers are those that represent more than 10% of our total revenue or accounts receivable, net balances for the periods and as of each balance sheet date presented, respectively. Revenue from these customers reflects their purchase of our products and services and our collaboration efforts with Genentech. For each significant customer, revenue as a percentage of total revenue for the periods presented and accounts receivable, net as a percentage of total accounts receivable, net as of the periods presented were as follows: Revenue Accounts Receivable, Net Three Months Ended September 30, Nine Months Ended September 30, September 30, December 31, 2020 2019 2020 2019 2020 2019 Customer A *% 16.0% *% 11.8% 16.4% 41.8% Customer B * 10.7 * * * * Customer C 10.3 * * * 21.4 * Genentech, Inc. 48.1 43.9 55.1 43.7 * * * less than 10% Revenue We recognize revenue in accordance with Accounting Standards Codification (“ASC”) Topic 606 (“ASC 606”), Revenue from Contracts with Customers Overview Our revenue is generated from immunosequencing (“sequencing”) products and services (“sequencing revenue”) and from regulatory or development support services leveraging our immune medicine platform (“development revenue”). When revenue generating contracts have elements of both sequencing revenue and development revenue, we classify revenue based on the nature of the performance obligation and the allocated transaction price. Sequencing Revenue Sequencing revenue reflects the amounts generated from providing sequencing services and testing through our clonoSEQ and immunoSEQ products and services to our clinical and research customers, respectively. For clinical customers, we derive revenues from providing our clonoSEQ test report to ordering physicians, and we bill and receive payments from medical institutions and commercial and government third-party payors. In these transactions, we have identified one performance obligation: the delivery of a clonoSEQ report. As payment from the respective payors may vary based on the various reimbursement rates and patient responsibilities, we consider the transaction price to be variable and record an estimate of the transaction price, subject to the constraint for variable consideration, as revenue at the time of delivery. The estimate of transaction price is based on historical and expected reimbursement rates with the various payors, which are monitored in subsequent periods and adjusted as necessary based on actual collection experience. For our clonoSEQ coverage under Medicare, we bill an episode of treatment when we deliver the first eligible test results. This billing contemplates all necessary tests required during a patient’s treatment cycle, which is currently estimated at approximately four tests per patient, including the initial sequence identification test. Revenue recognition commences at the time the initial billable test result is delivered and is based upon cumulative tests delivered to date. We estimate the number of tests we expect to deliver over a patient’s treatment cycle based on historical testing frequencies for patients by indication. These estimates are subject to change as we develop more information about utilization over time. Any unrecognized revenue from the initial billable test is recorded as deferred revenue and is recognized as we deliver the remaining tests in a patient’s treatment cycle. For research customers, contracts typically include an amount billed in advance of services (“upfront”) and subsequent billings as sample results are delivered to the customer. Upfront amounts received are recorded as deferred revenue, which we recognize as revenue upon satisfaction of performance obligations. We have identified two typical performance obligations under the terms of our research service contracts: sequencing services and related data analysis. We recognize revenue for both identified performance obligations as sample results are delivered to the customer. Development We derive revenue by providing services through development agreements to biopharmaceutical customers who seek access to our immune medicine platform technologies. We generate revenues from the delivery of professional support activities pertaining to the use of our proprietary immunoSEQ and clonoSEQ services in the development of the respective customers’ initiatives. The transaction price for these contracts may consist of a combination of non-refundable upfront fees, separately priced sequencing fees, progress-based milestones and regulatory milestones. The development agreements may include single or multiple performance obligations, depending on the contract. For certain contracts, we may perform services to support the biopharmaceutical customers’ regulatory submissions as part of their registrational trials. These services include regulatory support pertaining to our technology intended to be utilized as part of the submission, development of analytical plans for our sequencing data, participation on joint research committees and assistance in completing a regulatory submission. Generally, these services are not distinct within the context of the contract, and they are accounted for as a single performance obligation. When sequencing services are separately priced customer options, we assess if a material right exists and, if not, the customer option to purchase additional sequencing services is not considered part of the contract. Except for any non-refundable upfront fees, the other forms of compensation represent variable consideration. Variable consideration related to progress - based and regulatory milestones is estimated using the most likely amount method , where variable consideration is constrained until it is probable that a significant reversal of cumulative revenue recognized will not occur. Progress milestones , such as the first sample result delivered or final patient enrollment in a customer trial , are customer dependent and are included in the transaction price when the respective milestone is probable of occurring. Milestone payments that are not within our customers’ control, such as regulatory approvals, are not consider ed probable of being achieved until those approvals are received. Determining whether regulatory milestone payments are probable is an area that requires significant judgment. In making this assessment, we evaluate scientific, clinical, regulatory and other risks, as well as the level of effort and investment required to achieve the respective milestone. The primary method used to estimate standalone selling price for performance obligations is the adjusted market assessment approach. Using this approach, we evaluate the market in which we sell our services and estimate the price that a customer in that market would be willing to pay for our services. We recognize revenue using either an input or output measure of progress that faithfully depicts performance on a contract, depending on the contract. The measure used is dependent on the nature of the service to be provided in each contract. Selecting the measure of progress and estimating progress to date requires significant judgment. Net Loss Per Share Attributable to Common Shareholders We calculate basic net loss per share attributable to common shareholders by dividing the net loss attributable to common shareholders by the weighted-average number of shares of common stock outstanding for the period. The diluted net loss per share attributable to common shareholders is computed by giving effect to all potential dilutive common stock equivalents outstanding for the period determined using the treasury stock method. For purposes of this calculation, common stock warrants, stock options and restricted stock units are considered common stock equivalents but have been excluded from the calculation of diluted net loss per share attributable to common shareholders, as their effect is anti-dilutive. Prior to the closing of our initial public offering in July 2019 and the related conversion of our convertible preferred stock into common stock, we calculated our basic and diluted net loss per share attributable to common shareholders in conformity with the two-class method required for companies with participating securities. We considered our convertible preferred stock to be participating securities. In the event a dividend had been declared or paid on common stock, holders of convertible preferred stock would have been entitled to a share of such dividend in proportion to the holders of common stock on an as-if converted basis. Under the two-class method, basic net loss per share attributable to common shareholders is calculated by dividing the net loss attributable to common shareholders by the weighted-average number of shares of common stock outstanding for the period. Net loss attributable to common shareholders is determined by allocating undistributed earnings between common and preferred shareholders. The net loss attributable to common shareholders was not allocated to the convertible preferred stock under the two-class method, as the convertible preferred stock did not have a contractual obligation to share in our losses. The diluted net loss per share attributable to common shareholders was computed by giving effect to all potential dilutive common stock equivalents outstanding for the period determined using the treasury stock method. For purposes of this calculation, convertible preferred stock, convertible preferred stock warrants, common stock warrants, stock options and restricted stock units were considered common stock equivalents but were excluded from the calculation of diluted net loss per share attributable to common shareholders, as their effect was anti-dilutive. Recently Ad opted In February 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2016-02, Leases , Leases Targeted Improvements Leases In adopting the new standard, we utilized certain practical expedients available. These practical expedients include waiving reassessment of (1) whether any expired or existing contracts are or contain leases; (2) lease classification of expired or existing leases; and (3) initial direct costs for existing leases. We also elected to use hindsight in determining the lease term and in assessing impairment of our ROU assets. Furthermore, we have made a policy decision regarding our real estate leases not to separate nonlease components from lease components, to the extent they are fixed. We have also elected not to record on the balance sheet a lease that has a lease term of twelve months or less and does not contain a purchase option that we are reasonably certain to exercise. The standard had a material impact on our unaudited condensed balance sheets but did not have a material impact on our unaudited condensed statements of operations or unaudited condensed statements of cash flows. The most significant impact was the recognition of $33.0 million and $39.7 million of operating lease ROU assets and liabilities, respectively, and the derecognition of a $36.6 million asset and corresponding liability previously recorded pursuant to build-to-suit lease accounting guidance under ASC 840, which resulted in an increase to retained earnings of $0.1 million. The operating lease ROU assets and liabilities recorded at adoption included the derecognition of $7.3 million of deferred rent recognized as of December 31, 2019, as well as a $0.5 million reclassification of tenant incentive receivables previously recognized in the prepaid expenses and other current assets line item on our balance sheet. Refer to Note 8 of the accompanying notes to our unaudited condensed financial statements for additional information regarding leases. In June 2016, the FASB issued ASU 2016-13, Financial Instruments—Credit Losses Measurement of Credit Losses on Financial Instruments In August 2018, the FASB issued ASU No. 2018-15, Intangibles—Goodwill and Other: Internal-Use Software In December 2019, the FASB issued ASU No. 2019-12, Income Taxes Simplifying the Accounting for Income Taxes

Revenue

Revenue	9 Months Ended
	Sep. 30, 2020
Revenue From Contract With Customer [Abstract]
Revenue	3. Revenue MRD Development We have entered into agreements with biopharmaceutical customers to further develop and commercialize clonoSEQ and the biopharmaceutical customers’ therapeutics. Under each of the agreements, we received or will receive non-refundable upfront payments and could receive substantial additional payments upon reaching certain progress milestones or achievement of certain regulatory milestones pertaining to the customers’ therapeutics and our clonoSEQ test. Under the contracts, we identify performance obligations, which may include: (1) obligations to provide services supporting the customer’s regulatory submission activities as they relate to our clonoSEQ test; and (2) sequencing services related to customer-provided samples for their regulatory submissions. The transaction price allocated to the respective performance obligations is estimated using an adjusted market assessment approach for the regulatory support services and a standalone selling price for the estimated immunosequencing services. At contract inception, we fully constrain any consideration related to the regulatory milestones, as the achievement of such milestones is subject to third-party regulatory approval and the customers’ own submission decision-making. We recognize revenue relating to the sequencing services as sequencing revenue over time using an output method based on the proportion of sample results delivered relative to the total amount of sample results expected to be delivered and when expected to be a faithful depiction of progress. We use the same method to recognize the regulatory support services. When an output method based on the proportion of sample results delivered is not expected to be a faithful depiction of progress, we utilize an input method based on estimates of effort completed using a cost-based model. In the three and nine months ended September 30, 2020 and in the three and nine months ended September 30, 2019, we earned $2.5 million and $2.0 million, respectively, upon the achievement of certain regulatory milestones by us and our respective customers’ therapeutics. All $2.5 million and $2.0 million was recognized as revenue within the respective periods, as we determined these amounts were consistent with our estimated standalone selling price and the respective performance obligations were complete. As of September 30, 2020, in future periods we could receive up to an additional $313.5 million in milestone payments if certain regulatory approvals are obtained by our customers’ therapeutics in connection with MRD data generated from our clonoSEQ test. Genentech In December 2018, we entered into a worldwide collaboration and license agreement (“Genentech Agreement”) with Genentech to leverage our capability to develop cellular therapies in oncology. Subsequent to receipt of regulatory approval in January 2019, we received a non-refundable, upfront payment of $300.0 million in February 2019 and may be eligible to receive more than $1.8 billion over time, including payments of up to $75.0 million upon the achievement of specified regulatory milestones, up to $300.0 million upon the achievement of specified development milestones and up to $1,430.0 million upon the achievement of specified commercial milestones. In addition, we are separately able to receive tiered royalties at a rate ranging from the mid-single digits to the mid-teens on aggregate worldwide net sales of products arising from the strategic collaboration, subject to certain reductions, with aggregate minimum floors. Under the agreement, we are pursuing two product development pathways for novel T cell immunotherapies in which Genentech intends to use T cell receptors (“TCRs”) screened by our immune medicine platform to engineer and manufacture cellular medicines: • Shared Products. The shared products will use “off-the-shelf” TCRs identified against cancer antigens shared among patients (“Shared Products”). • Personalized Product. The personalized product will use patient-specific TCRs identified by real-time screening of TCRs against cancer antigens in each patient (“Personalized Product”). Under the terms of the agreement, we granted Genentech exclusive worldwide licenses to develop and commercialize TCR-based cellular therapies in the field of oncology, including licenses to existing shared antigen data packages. Additionally, Genentech has the right to determine which product candidates to further develop for commercialization purposes. We determined that this arrangement meets the criteria set forth in ASC Topic 808, Collaborative Arrangements In applying ASC 606, we identified the following performance obligations at the inception of the agreement: 1. License to utilize on an exclusive basis all TCR-specific platform intellectual property to develop and commercialize any licensed products in the field of oncology. 2. License to utilize all data and information within each shared antigen data package and any other know-how disclosed by us to Genentech in oncology. 3. License to utilize all private antigen TCR product data in connection with research and development activities in the field of use. 4. License to existing shared antigen data packages. 5. Research and development services for shared product development, including expansion of shared antigen data packages. 6. Research and development services for private product development. 7. Obligations to participate on various joint research, development and project committees. We determined that none of the licenses, research and development services or obligations to participate on various committees were distinct within the context of the contract , given such rights and activities were highly interrelated and there was substantial additional research and development to further develop the licenses. We considered factors such as the stage of development of the respective existing antigen data packages, the subsequent development that would be required to both identify and submit a potential target for investigational new drug acceptance under both product pathways and the variability in research and development pathways given Genentech’s control of product commercialization. Specifically, under the agreement, Genentech is not required to pursue development or commercialization activities pertaining to both product pathways and may choose to proceed with one or the other , as opposed to both. Accordingly, we determined that all of the identified performance obligations were attributable to one general performance obligation, which is to further the development of our TCR-specific platform, including data packages, and continue to make our TCR identification process available to Genentech to pursue either product pathway. Separately, we have a responsibility to Genentech to enter into a supply and manufacturing agreement for patient-specific TCRs as it pertains to any Personalized Product therapeutic. We determined this was an option right of Genentech should they pursue commercialization of a Personalized Product therapy. Because of the uncertainty resulting from the early stage of development, the novel approach of our collaboration with Genentech and our rights to future commercial milestones and royalty payments, we determined that this option right was not a material right that should be accounted for at inception. As such, we will account for the supply and manufacturing agreement when entered into between the parties. We determined the initial transaction price shall be made up of only the $300.0 million upfront, non-refundable payment, as all potential regulatory and development milestone payments were probable of significant revenue reversal given their achievement was highly dependent on factors outside our control. As a result, these payments were fully constrained and were not included in the transaction price as of September 30, 2020. We excluded the commercial milestones and potential royalties from the transaction price, as those items relate predominantly to the license rights granted to Genentech and will be assessed when and if such events occur. As there are potential substantive developments necessary, which Genentech may be able to direct, we determined that we would apply a proportional performance model to recognize revenue for our performance obligation. We measure proportional performance using an input method based on costs incurred relative to the total estimated costs of research and development efforts to pursue both the Shared Product and Personalized Product pathways. We currently expect to recognize the revenue over a period of approximately seven to eight years from the effective date. This estimate of the research and development period considers pursuit options of development activities supporting both the Shared Product and the Personalized Product, but may be reduced or increased based on the various activities as directed by the joint committees, decisions made by Genentech, regulatory feedback or other factors not currently known. We recognized revenue of $12.3 million and $11.4 million during the three months ended September 30, 2020 and 2019, respectively, and $35.9 million and $26.2 million during the nine months ended September 30, 2020 and 2019, respectively, related to the Genentech Agreement. Costs related to the Genentech Agreement are included in research and development expenses.

Fair Value Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2020
Fair Value Disclosures [Abstract]
Fair Value Measurements	4. Fair Value The following tables set forth the fair value of financial assets as of September 30, 2020 and December 31, 2019 that were measured at fair value on a recurring basis (in thousands): September 30, 2020 Level 1 Level 2 Level 3 Total Financial assets Money market funds $ 495,115 $ — $ — $ 495,115 U.S. government debt and agency securities — 340,836 — 340,836 Corporate bonds — 13,634 — 13,634 Total financial assets $ 495,115 $ 354,470 $ — $ 849,585 December 31, 2019 Level 1 Level 2 Level 3 Total Financial assets Money market funds $ 88,683 $ — $ — $ 88,683 Commercial paper — 121,867 — 121,867 U.S. government debt and agency securities — 377,243 — 377,243 Corporate bonds — 86,615 — 86,615 Total financial assets $ 88,683 $ 585,725 $ — $ 674,408 Level 1 securities include highly liquid money market funds, for which we measure the fair value based on quoted prices in active markets for identical assets or liabilities. Level 2 securities consist of U.S. government debt securities, commercial paper and corporate bonds, and are valued based on recent trades of securities in inactive markets or based on quoted market prices of similar instruments and other significant inputs derived from or corroborated by observable market data.

Investments

Investments	9 Months Ended
	Sep. 30, 2020
Investments Debt And Equity Securities [Abstract]
Investments	5. Investments Available-for-sale investments consisted of the following as of September 30, 2020 and December 31, 2019 (in thousands): September 30, 2020 Amortized Cost Unrealized Gain Unrealized Loss Estimated Fair Value Short-term marketable securities U.S. government debt and agency securities $ 323,338 $ 1,034 $ (2 ) $ 324,370 Corporate bonds 13,502 134 (2 ) 13,634 Total short-term marketable securities $ 336,840 $ 1,168 $ (4 ) $ 338,004 Long-term marketable securities U.S. government debt and agency securities $ 16,203 $ 263 $ — $ 16,466 Total long-term marketable securities $ 16,203 $ 263 $ — $ 16,466 December 31, 2019 Amortized Cost Unrealized Gain Unrealized Loss Estimated Fair Value Short-term marketable securities Commercial paper $ 121,866 $ — $ — $ 121,866 U.S. government debt and agency securities 285,963 394 (1 ) 286,356 Corporate bonds 71,962 109 (3 ) 72,068 Total short-term marketable securities $ 479,791 $ 503 $ (4 ) $ 480,290 Long-term marketable securities U.S. government debt and agency securities $ 90,750 $ 146 $ (9 ) $ 90,887 Corporate bonds 14,513 35 — 14,548 Total long-term marketable securities $ 105,263 $ 181 $ (9 ) $ 105,435 All the commercial paper, U.S. government debt and agency securities and corporate bonds designated as short-term marketable securities have an effective maturity date that is equal to or less than one year from the respective balance sheet date. Those that are designated as long-term marketable securities have an effective maturity date that is more than one year from the respective balance sheet date. Accrued interest receivable is excluded from the amortized cost and estimated fair value of our marketable securities. Accrued interest receivables of $1.4 million and $2.2 million were presented separately within the prepaid expenses and other current assets line item on our unaudited condensed balance sheet as of September 30, 2020 and on our balance sheet as of December 31, 2019, respectively. We have made an accounting policy election to not measure an allowance for credit losses for accrued interest receivables. The following table presents the gross unrealized holding losses and fair value for investments in an unrealized loss position, and the length of time that individual securities have been in a continuous loss position, as of September 30, 2020 (in thousands): Less Than 12 Months 12 Months Or Greater Fair Value Unrealized Loss Fair Value Unrealized Loss U.S. government debt and agency securities $ 75,564 $ (2 ) $ — $ — Corporate bonds 1,522 (2 ) — — Total available-for-sale securities $ 77,086 $ (4 ) $ — $ — We periodically review our available-for-sale securities to assess for credit impairment. Some of the factors considered in assessing impairment include the extent to which the fair value is less than the amortized cost basis, adverse conditions related to the security, an industry or geographic area, changes to security ratings or sector credit ratings and other relevant market data. As of September 30, 2020, we did not intend, nor were we more likely than not to be required, to sell our available-for-sale investments before the recovery of their amortized cost basis, which may be maturity. Based on our assessment, we concluded all impairment as of September 30, 2020 to be due to factors other than credit loss, such as changes in interest rates. A credit allowance was not recognized and the impairment of our available-for-sale securities was recorded in other comprehensive loss.

Goodwill and Intangible Assets

Goodwill and Intangible Assets	9 Months Ended
	Sep. 30, 2020
Goodwill And Intangible Assets Disclosure [Abstract]
Goodwill and Intangible Assets	6 . Goodwill There have been no changes in the carrying amount of goodwill since its recognition in 2015. Intangible assets subject to amortization as of September 30, 2020 and December 31, 2019 consisted of the following (in thousands): September 30, 2020 Gross Carrying Amount Accumulated Amortization Net Carrying Amount Acquired developed technology $ 20,000 $ (9,552 ) $ 10,448 Purchased intellectual property 325 (120 ) 205 Balance at September 30, 2020 $ 20,325 $ (9,672 ) $ 10,653 December 31, 2019 Gross Carrying Amount Accumulated Amortization Net Carrying Amount Acquired developed technology $ 20,000 $ (8,301 ) $ 11,699 Purchased intellectual property 325 (96 ) 229 Balance at December 31, 2019 $ 20,325 $ (8,397 ) $ 11,928 The developed technology was acquired in connection with our acquisition of Sequenta, Inc. (“Sequenta”) in 2015. The remaining balance of the acquired technology and the purchased intellectual property is expected to be amortized over the next 6.3 years. As of September 30, 2020, expected future amortization expense for intangible assets was as follows (in thousands): 2020 (excluding the nine months ended September 30, 2020) $ 428 2021 1,699 2022 1,699 2023 1,699 2024 1,703 Thereafter 3,425 Total future amortization expense $ 10,653

Deferred Revenue

Deferred Revenue	9 Months Ended
	Sep. 30, 2020
Revenue From Contract With Customer [Abstract]
Deferred Revenue	7 . Deferred Revenue Deferred revenue by revenue classification as of September 30, 2020 and December 31, 2019 was as follows (in thousands): September 30, 2020 December 31, 2019 Current deferred revenue Sequencing $ 16,040 $ 12,482 Development 62,152 48,512 Total current deferred revenue 78,192 60,994 Non-current deferred revenue Sequencing 637 1,459 Development 174,216 217,873 Total non-current deferred revenue 174,853 219,332 Total current and non-current deferred revenue $ 253,045 $ 280,326 Deferred revenue from our Genentech Agreement represents $59.9 million and $169.1 million of the current and non-current development deferred revenue balances, respectively, at September 30, 2020 and $48.1 million and $216.8 million of the current and non-current development deferred revenue balances, respectively, at December 31, 2019. In general, we expect that the current amounts will be recognized as revenue within 12 months and the non-current amounts will be recognized as revenue over a period of approximately six to seven years. This period of time represents an estimate of the research and development period to develop cellular therapies in oncology, which may be reduced or increased based on the various development activities. Changes in deferred revenue during the nine months ended September 30, 2020 were as follows (in thousands): Deferred revenue balance at December 31, 2019 $ 280,326 Additions to deferred revenue during the period 19,859 Revenue recognized during the period (47,140 ) Deferred revenue balance at September 30, 2020 $ 253,045 As of September 30, 2020, $41.9 million was recognized as revenue that was included in the deferred revenue balance at December 31, 2019. As a result of cancelled customer sequencing contracts, we recognized $0.5 million and $0.9 million of sequencing revenue during the three and nine months ended September 30, 2020, respectively.

Leases

Leases	9 Months Ended
	Sep. 30, 2020
Lessee Disclosure [Abstract]
Leases	8. Leases We have operating lease agreements for the laboratory and office facilities that we occupy in Seattle, Washington and South San Francisco, California, as well as server space. Our leases include an amendment to our previous lease in South San Francisco, California to rent 19,867 additional square feet, which commenced during the nine months ended 30, 2020 and provides for a $0.6 million tenant improvement allowance. As of 30, 2020, we were not party to any finance leases. Our leases have remaining terms of 1.6 years to 11.8 years, and include options to extend certain of the leases up to 10.0 years and terminate certain of the leases after 3.0 years. We adjust lease terms for these options only when it is reasonably certain we will exercise these options. As of 30, 2020, it was reasonably certain that we would exercise our option to terminate of our leases after 3.0 years. Other information related to our operating leases as of 30, 2020 was as follows: Weighted-average remaining lease term (in years) 9.66 Weighted-average discount rate 4.6 % The following table reconciles our undiscounted operating lease cash flows to our operating lease liabilities as of 30, 2020 (in thousands): 2020 (excluding the nine months ended September 30, 2020) $ 1,532 2021 6,887 2022 6,886 2023 6,450 2024 5,956 Thereafter 30,979 Total undiscounted lease payments 58,690 Less: Imputed interest rate (11,682 ) Tenant improvement receivables (673 ) Total operating lease liabilities $ 46,335 Less: current portion (3,969 ) Operating lease liabilities, less current portion $ 42,366 Operating lease expense was $1.4 million and $3.7 million for the three and nine months ended 30, 2020, respectively. Variable lease expense for operating leases was $0.7 million and $1.8 million for the three and nine months ended 30, 2020, respectively. Rent expense recognized under ASC 840, inclusive of operating and maintenance costs, was $1.3 million and $3.6 million for the three and nine months ended 30, 2019, respectively. Cash paid for amounts included in the measurement of lease liabilities for the nine months ended 30, 2020 was $1.8 million, net of $1.8 million of cash received for tenant improvement allowances. Lease Not Yet Commenced In August 2019, we entered into an agreement to rent 100,000 square feet in a to-be-constructed building in Seattle, Washington. In connection with the lease, we entered into a $2.1 million letter of credit with one of our existing financial institutions. Due to our involvement during the construction process of the leased building, we qualified as the deemed owner of the building under build-to-suit lease accounting guidance that proceeded ASC 842. The resulting asset and long-term financing obligation recorded on our balance sheet for the cost of the building was derecognized upon adoption of ASC 842. As of 30, 2020, we have incurred $2.4 million in certain tenant improvement costs relating to the to-be-constructed building, which are presented within the other long-term liabilities line item on our unaudited condensed balance sheet as of 30, 2020. These costs will be reimbursed by the landlord. The related receivable of $2.4 million is presented within the prepaid expenses and other current assets line item on our unaudited condensed balance sheet as of 30, 2020. T his lease will be assessed for classification and a lease liability and corresponding ROU asset will be recorded upon lease commencement. Future non-cancellable undiscounted lease payments total $89.8 million, payable over the lease term of 12.7 years.

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2020
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	9 . Commitments and Contingencies Legal Proceedings We are subject to claims and assessments from time to time in the ordinary course of business. We will accrue a liability for such matters when it is probable that a liability has been incurred and the amount can be reasonably estimated. When only a range of possible loss can be established, the most probable amount in the range is accrued. If no amount within this range is a better estimate than any other amount within the range, the minimum amount in the range is accrued. We are not currently party to any material legal proceedings. Indemnification Agreements In the ordinary course of business, we may provide indemnification of varying scope and terms to vendors, lessors, customers and other parties with respect to certain matters including, but not limited to, losses arising out of breach of our agreements with them or from intellectual property infringement claims made by third parties. In addition, we have entered into indemnification agreements with members of our board of directors and certain of our executive officers that will require us to indemnify them against certain liabilities that may arise by reason of their status or service as directors or officers. The maximum potential amount of future payments that we could be required to make under these indemnification agreements is, in many cases, unlimited. We have not incurred any material costs as a result of such indemnifications and are not currently aware of any indemnification claims.

Shareholders' Equity

Shareholders' Equity	9 Months Ended
	Sep. 30, 2020
Equity [Abstract]
Shareholders' Equity	10 . Shareholders’ Convertible Preferred Stock Immediately prior to the completion of our initial public offering on July 1, 2019, 93,039,737 shares of convertible preferred stock then outstanding converted into an equivalent number of shares of common stock. As of September 30, 2020, no shares of convertible preferred stock were outstanding. Preferred Stock We are authorized to issue 10,000,000 shares of preferred stock, par value $0.0001 per share. As of September 30, 2020, no shares of preferred stock were outstanding. Common Stock We are authorized to issue 340,000,000 shares of common stock. Our common stock has a par value of $0.0001, no preferences or privileges and is not redeemable. Holders of our common stock are entitled to one vote for each share of common stock held. The holders of record of outstanding shares of common stock shall be entitled to receive, when, as and if declared, out of funds legally available, such cash and other dividends as may be declared from time to time. As of September 30, 2020, we had 136,392,256 shares of common stock outstanding. As of September 30, 2020, we have reserved shares of common stock for the following: Shares issuable upon the exercise of outstanding common stock options and the vesting of outstanding common restricted stock units granted 15,567,900 Shares available for future grant under the 2019 Equity Incentive Plan 18,787,301 Shares available for future grant under the Employee Stock Purchase Plan 2,804,298 Shares to be issued upon exercise of a common stock warrant 56,875 Total shares of common stock reserved for future issuance 37,216,374 Our 2019 Equity Incentive Plan (“2019 Plan”) provides for annual increases in the number of shares that may be issued under the 2019 Plan on January 1, 2020 and on each subsequent January 1, thereafter, by a number of shares equal to the lesser of (a) 5% of the number of shares of common stock issued and outstanding on the immediately preceding December 31, or (b) an amount determined by our board of directors. Furthermore, our Employee Stock Purchase Plan (“ESPP”) provides for annual increases in the number of shares available for issuance under our ESPP on January 1, 2020 and on each January 1, thereafter, by a number of shares equal to the smallest of (a) 1% of the number of shares of common stock issued and outstanding on the immediately preceding December 31, or (b) an amount determined by our board of directors. On January 1, 2020, our 2019 Plan and ESPP reserves automatically increased by 6,261,907 shares and 1,252,381 shares, respectively. Common In 2014, we issued a warrant to purchase 56,875 shares of Series C convertible preferred stock at an exercise price of $2.64. The warrant is exercisable for a period of seven years from the date of issuance. Immediately prior to and in connection with the completion of our initial public offering on July 1, 2019, this convertible preferred stock warrant, which was previously recorded as a financial liability, was converted to a warrant to purchase the same number of shares of common stock. Upon conversion, the financial liability was reclassified to the additional paid-in capital line item on our unaudited condensed balance sheet. The warrant to purchase 56,875 shares of common stock remains outstanding as of September 30, 2020.

Equity Incentive Plans

Equity Incentive Plans	9 Months Ended
	Sep. 30, 2020
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Equity Incentive Plans	1 1 . Equity Incentive Plans Sequenta 2008 Stock Plan, as amended In connection with our acquisition of Sequenta in January 2015, we assumed Sequenta’s Equity Incentive Plan (“2008 Plan”), including all outstanding options and shares available for future issuance under the 2008 Plan, which, prior to the completion of our initial public offering, were all exercisable for Series E-1 convertible preferred stock. Upon completion of our initial public offering in July 2019, the outstanding options were exercisable for common stock. No shares are available for future issuance under this plan and no equity awards are outstanding under this plan as of September 30, 2020. Adaptive 2009 Equity Incentive Plan We adopted an equity incentive plan in 2009 (“2009 Plan”) that provided for the issuance of incentive and nonqualified common stock options and other share-based awards for employees, directors and consultants. Under the 2009 Plan, the option exercise price for incentive and nonqualified stock options were not to be less than the fair market value of our common stock at the date of grant. Options granted under this plan expire no later than ten years from the grant date and vesting was established at the time of grant. Pursuant to the terms of the 2019 Plan, any shares subject to outstanding options originally granted under the 2009 Plan that terminate, expire or lapse for any reason without the delivery of shares to the holder thereof shall become available for issuance pursuant to awards granted under the 2019 Plan. While no shares are available for future issuance under the 2009 Plan, it continues to govern outstanding equity awards granted thereunder. 2019 Equity Incentive Plan The 2019 Plan was approved by our shareholders on June 13, 2019 and, pursuant to the resolutions adopted by our board of directors, became effective immediately prior to the closing of our initial public offering. The 2019 Plan provides for the issuance of awards in the form of options and other share-based awards for employees, directors and consultants. Under the 2019 Plan, the option exercise price per share shall not be less than the fair market value of a share of stock on the grant date of the option, as defined by the 2019 Plan, unless explicitly qualified under the provisions of Section 409A or Section 424(a) of the Internal Revenue Code of 1986. Additionally, unless otherwise specified, options granted under this plan expire no later than ten years from the grant date and vesting is established at the time of grant. Except for certain option grants made to non-employee directors, stock options granted under the 2019 Plan generally vest over a four-year Changes in shares available for grant during the nine months ended September 30, 2020 were as follows: Shares Available for Grant Shares available for grant at December 31, 2019 15,396,254 2019 Plan reserve increase on January 1, 2020 6,261,907 Options and restricted stock units granted (3,070,331 ) Options and restricted stock units forfeited, cancelled or expired 199,471 Shares available for grant at September 30, 2020 18,787,301 Stock option activity under the 2008 Plan, 2009 Plan and 2019 Plan during the nine months ended September 30, 2020 was as follows: Shares Subject to Outstanding Options Weighted- Average Exercise Price per Share Aggregate Intrinsic Value (in thousands) Options outstanding at December 31, 2019 16,646,654 $ 6.14 $ 398,379 Options granted 3,020,331 31.98 Options forfeited or cancelled (184,471 ) 14.19 Options expired (15,000 ) 0.16 Options exercised (3,949,614 ) 3.91 Options outstanding at September 30, 2020 15,517,900 $ 11.65 $ 573,922 Options vested and exercisable at September 30, 2020 8,604,883 $ 5.97 $ 367,072 The weighted-average remaining contractual life for options outstanding at September 30, 2020 was 7.1 years. The weighted-average remaining contractual life for vested and exercisable options outstanding at September 30, 2020 was 5.9 years. Of the $15.5 million proceeds from exercise of stock options included on our unaudited condensed statements of cash flows for the nine months ended September 30, 2020, $0.5 million related to options exercised prior to but settled during the nine months ended September 30, 2020. As of September 30, 2020, $0.4 million was included in the prepaid expenses and other current assets line item on our unaudited condensed balance sheet for unsettled cash proceeds related to options exercised. As of December 31, 2019, 4,500 shares of restricted stock units (“RSUs”), with a weighted-average grant date fair value per share of $41.63, were nonvested and outstanding. We granted 50,000 shares of RSUs, with a weighted-average grant date fair value per share of $28.10, during the nine months ended September 30, 2020. During the nine months ended September 30, 2020, 4,500 shares of RSUs, with a weighted-average grant date fair value per share of $41.63, vested. As of September 30, 2020, 50,000 shares of RSUs, with a weighted-average grant date fair value per share of $28.10, remained nonvested and outstanding. Fair Value of Options and Grant Date Fair Value of Restricted Stock Units The estimated fair value of options granted during the nine months ended September 30, 2020 and 2019 was estimated using the Black-Scholes option-pricing model with the following assumptions: Nine Months Ended September 30, 2020 2019 Grant date fair value $17.68 - $48.54 $7.80 - $47.81 Expected term (in years) 5.27 - 6.08 5.27 - 6.08 Risk-free interest rate 0.4% - 1.7% 1.4% - 2.5% Expected volatility 70.5% - 73.0% 64.3% - 72.9% Expected dividend yield — — The weighted-average volatility used in the fair value calculations of options granted during the nine months ended September 30, 2020 and 2019 was 71.2% and 68.0%, respectively. The determination of the fair value of stock options on the date of grant using a Black-Scholes option-pricing model is affected by the estimated fair value of our common stock, as well as assumptions regarding a number of variables that are complex, subjective and generally require significant judgment to determine. The valuation assumptions were determined as follows: Fair value of common stock— Prior to the closing of our initial public offering, the grant date fair value of our common stock was determined with input from management using valuation methodologies which utilized certain assumptions, including probability weighting of events, volatility, time to liquidation, a risk-free interest rate and an assumption for a discount for lack of marketability (Level 3 inputs). In determining the fair value of our common stock, the methodologies used to estimate the enterprise value were performed using methodologies, approaches and assumptions consistent with the American Institute of Certified Public Accountants Accounting and Valuation Guide, . For valuations of grants made after the closing of our initial public offering, the fair value of each share of common stock is based on the closing price of our common stock on the date of grant, or other relevant determination date, as reported on The Nasdaq Global Select Market. Expected term —The expected term of options granted to employees and non-employee directors is determined using the “simplified” method, as illustrated in ASC Topic 718, , as we do not have sufficient exercise history to determine a better estimate of expected term. Under this approach, the expected term is based on the midpoint between the vesting date and the end of the contractual term of the option. Risk-free interest rate —We utilize a risk-free interest rate in the option valuation model based on U.S. Treasury zero-coupon issues with remaining terms similar to the expected terms of the options. Expected volatility —As we do not have sufficient trading history for our common stock, the expected volatility is based on the historical volatility of our publicly traded industry peers utilizing a period of time consistent with our estimate of the expected term. Expected dividend yield —We do not anticipate paying any cash dividends in the foreseeable future and, therefore, use an expected dividend yield of zero in the option valuation model. The grant date fair value of RSUs granted after the closing of our initial public offering is based on the closing price of our common stock on the date of grant, or other relevant determination date, as reported on The Nasdaq Global Select Market. Share-based compensation expense of $6.5 million and $3.3 million was recognized during the three months ended September 30, 2020 and 2019, respectively, and $17.5 million and $9.7 million was recognized during the nine months ended September 30, 2020 and 2019, respectively. The compensation costs related to stock options and RSUs for the three and nine months ended September 30, 2020 and 2019, respectively, are included on our statements of operations as follows (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2020 2019 2020 2019 Cost of revenue $ 206 $ 133 $ 587 $ 376 Research and development 2,216 943 5,912 2,838 Sales and marketing 1,759 798 4,583 2,647 General and administration 2,289 1,461 6,436 3,852 Total share-based compensation expense $ 6,470 $ 3,335 $ 17,518 $ 9,713 At September 30, 2020, unrecognized share-based compensation expense related to unvested stock options was $75.5 million, which is expected to be recognized over a remaining weighted-average period of 3.1 years. Additionally, at September 30, 2020, unrecognized share-based compensation expense related to unvested RSUs was $1.2 million, which is expected to be recognized over a remaining weighted-average period of 3.5 years.

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2020
Income Tax Disclosure [Abstract]
Income Taxes	12. Income Taxes The effective tax expense was $0.7 million and the effective tax benefit was $1.1 million for the three and nine months ended September 30, 2020, respectively. There was no effective tax benefit for the year ended December 31, 2019. We calculate our tax provision by applying a forecasted annual effective tax rate (“AETR”) against year-to-date pre-tax loss, and taking into account certain discrete items, primarily related to the exercise activity of stock options, in the quarter in which they occur. We recorded an income tax expense for the three months ended September 30, 2020 and an income tax benefit for the nine months ended September 30, 2020 because the discrete benefit from option exercises was greater than the year-to-date AETR tax expense. We do not expect to recognize any tax expense or benefit on a full year basis, inclusive of discrete items. We file income tax returns in the U.S. federal jurisdiction and various U.S. state jurisdictions. Significant disputes may arise with authorities involving issues of the timing and amount of deductions, the use of tax credits and allocations of income and expenses among various tax jurisdictions because of differing interpretations of tax laws, regulations and the relevant facts. We believe our accrual for income tax liabilities is appropriate based on past experience, interpretations of tax law and judgments about potential actions by tax authorities; however, due to the complexity of the provision for income taxes, the ultimate resolution of any tax matters may result in payments greater or less than amounts accrued. Because of net operating loss carryforwards, substantially all tax years since inception remain open to federal and state tax examination. On March 27, 2020, the U.S. enacted the Coronavirus Aid, Relief and Economic Security Act (“CARES Act”) to provide emergency economic stimulus in light of the effects of COVID-19. While the CARES Act provides extensive tax changes, some of the more significant provisions include removing certain limitations on utilization of net operating losses, increasing the loss carryback period for certain losses to five years and increasing the ability to deduct interest expense, as well as amending certain provisions of the previously enacted Tax Cuts and Jobs Act of 2017 (“TCJA”). We are still evaluating the CARES Act, but do not anticipate a significant impact to our income tax provision.

Net Loss Per Share Attributable

Net Loss Per Share Attributable to Common Shareholders	9 Months Ended
	Sep. 30, 2020
Earnings Per Share [Abstract]
Net Loss Per Share Attributable to Common Shareholders	1 3 . Net Loss Shareholders Net Loss The following table sets forth the computation of the basic and diluted net loss per share attributable to common shareholders for the three and nine months ended September 30, 2020 and 2019, respectively (in thousands, except share and per share amounts): Three Months Ended September 30, Nine Months Ended September 30, 2020 2019 2020 2019 Net loss $ (36,719 ) $ (13,950 ) $ (101,657 ) $ (47,995 ) Fair value adjustments to redemption value for Series E-1 convertible preferred stock options — — — (964 ) Net loss attributable to common shareholders, basic and diluted $ (36,719 ) $ (13,950 ) $ (101,657 ) $ (48,959 ) Weighted-average shares used in computing net loss per share 134,372,026 124,285,686 129,289,948 50,552,389 Net loss per share attributable to common shareholders, basic and diluted $ (0.27 ) $ (0.11 ) $ (0.79 ) $ (0.97 ) Since we were in a loss position for all periods presented, basic net loss per share attributable to common shareholders is the same as diluted net loss per share attributable to common shareholders, as the inclusion of all potential shares of common stock outstanding would have been anti-dilutive. The following weighted-average common stock equivalents were excluded from the calculation of diluted net loss per share attributable to common shareholders for the three and nine months ended September 30, 2020 and 2019, respectively, as they had an anti-dilutive effect: Three Months Ended September 30, Nine Months Ended September 30, 2020 2019 2020 2019 Convertible preferred stock (on as if converted basis) — — — 61,641,506 Stock options issued and outstanding 15,718,821 17,466,409 16,484,334 17,096,516 Unvested restricted stock units 50,000 7,380 34,138 2,487 Common stock warrants 56,875 56,875 56,875 55,653 Convertible preferred stock warrants — — — 37,708 Total 15,825,696 17,530,664 16,575,347 78,833,870

Significant Accounting Polici_2

Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2020
Accounting Policies [Abstract]
Basis of Presentation and Use of Estimates	Basis The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America (“GAAP”) requires management to make certain estimates, judgments and assumptions that affect the reported amounts of assets and liabilities and the related disclosures at the date of the financial statements, as well as the reported amounts of revenues and expenses during the periods presented. We base our estimates on historical experience and other relevant assumptions that we believe to be reasonable under the circumstances. Estimates are used in several areas including, but not limited to, estimates of progress to date for certain performance obligations and the transaction price for certain contracts with customers, share-based compensation, including the fair value of stock, the provision for income taxes, including related reserves, and goodwill, among others. These estimates generally involve complex issues and require judgments, involve the analysis of historical results and prediction of future trends, can require extended periods of time to resolve and are subject to change from period to period. Actual results may differ materially from management’s estimates.
Unaudited Interim Condensed Financial Statements	Unaudited Interim Condensed Financial Statements In our opinion, the accompanying unaudited condensed financial statements have been prepared in accordance with GAAP for interim financial information. These unaudited condensed financial statements include all adjustments necessary to fairly state the financial position and the results of our operations and cash flows for interim periods in accordance with GAAP. All such adjustments are of a normal, recurring nature. Interim-period results are not necessarily indicative of results of operations or cash flows for a full year or any subsequent interim period. The accompanying unaudited condensed financial statements should be read in conjunction with our audited financial statements and notes included in our Annual Report on Form 10-K for the year ended December 31, 2019 filed with the SEC on February 26, 2020.
Reclassifications	Reclassifications In the accompanying unaudited condensed statements of cash flows, certain prior year amounts have been reclassified to conform to the current period presentation. Specifically, the gain on equipment disposals line item and other line item were previously separately stated and are now presented together in the other line item. There was no change to net cash provided by operating activities as a result of the reclassification.
Restricted Cash	Restricted Cash We are required to maintain certain balances under lease arrangements for our property and facility leases. We had restricted cash of $2.1 million as of September 30, 2020 and December 31, 2019.
Leases	Leases We determine if an arrangement contains a lease at inception. We have operating lease agreements for the laboratory and office facilities that we occupy, as well as server space. Operating lease right-of-use (“ROU”) assets and operating lease liabilities are recognized at the date the underlying asset becomes available for our use and are based on the present value of the future minimum lease payments over the lease term. ROU assets also include any initial direct costs incurred and any lease payments made at or before the lease commencement date, less lease incentives received. As our leases generally do not provide an implicit interest rate, the present value of our future minimum lease payments is determined using our incremental borrowing rate. This rate is an estimate of the collateralized borrowing rate we would incur on our future lease payments over a similar term and is based on the information available to us at the lease commencement date, or as of January 1, 2020 for commenced leases that existed as of our adoption of the new lease standard, discussed in more detail below. Certain of our leases contain options to extend or terminate the lease; lease terms are adjusted for these options only when it is reasonably certain we will exercise these options. Our lease agreements do not contain residual value guarantees or covenants. We have made a policy election regarding our real estate leases not to separate nonlease components from lease components, to the extent they are fixed. Nonlease components that are not fixed are expensed as incurred as variable lease expense. Our leases for laboratory and office facilities typically include variable nonlease components, such as common-area maintenance costs. We have also elected not to record on the balance sheet a lease that has a lease term of twelve months or less and does not contain a purchase option that we are reasonably certain to exercise. Lease expense is recognized on a straight-line basis over the terms of the leases. Incentives granted under our facilities leases, including rent holidays, are recognized as adjustments to lease expense on a straight-line basis over the terms of the leases.
Concentrations of Risk	Concentrations We are subject to a concentration of risk from a limited number of suppliers, or in some cases, single suppliers for some of our laboratory instruments and materials. This risk is managed by targeting a quantity of surplus stock. Cash, cash equivalents and marketable securities are financial instruments that potentially subject us to concentrations of credit risk. We invest in money market funds, United States (“U.S.”) government debt securities, U.S. government agency securities, commercial paper and corporate bonds with high-quality accredited financial institutions. Significant customers are those that represent more than 10% of our total revenue or accounts receivable, net balances for the periods and as of each balance sheet date presented, respectively. Revenue from these customers reflects their purchase of our products and services and our collaboration efforts with Genentech. For each significant customer, revenue as a percentage of total revenue for the periods presented and accounts receivable, net as a percentage of total accounts receivable, net as of the periods presented were as follows: Revenue Accounts Receivable, Net Three Months Ended September 30, Nine Months Ended September 30, September 30, December 31, 2020 2019 2020 2019 2020 2019 Customer A *% 16.0% *% 11.8% 16.4% 41.8% Customer B * 10.7 * * * * Customer C 10.3 * * * 21.4 * Genentech, Inc. 48.1 43.9 55.1 43.7 * * * less than 10%
Revenue Recognition	Revenue We recognize revenue in accordance with Accounting Standards Codification (“ASC”) Topic 606 (“ASC 606”), Revenue from Contracts with Customers Overview Our revenue is generated from immunosequencing (“sequencing”) products and services (“sequencing revenue”) and from regulatory or development support services leveraging our immune medicine platform (“development revenue”). When revenue generating contracts have elements of both sequencing revenue and development revenue, we classify revenue based on the nature of the performance obligation and the allocated transaction price. Sequencing Revenue Sequencing revenue reflects the amounts generated from providing sequencing services and testing through our clonoSEQ and immunoSEQ products and services to our clinical and research customers, respectively. For clinical customers, we derive revenues from providing our clonoSEQ test report to ordering physicians, and we bill and receive payments from medical institutions and commercial and government third-party payors. In these transactions, we have identified one performance obligation: the delivery of a clonoSEQ report. As payment from the respective payors may vary based on the various reimbursement rates and patient responsibilities, we consider the transaction price to be variable and record an estimate of the transaction price, subject to the constraint for variable consideration, as revenue at the time of delivery. The estimate of transaction price is based on historical and expected reimbursement rates with the various payors, which are monitored in subsequent periods and adjusted as necessary based on actual collection experience. For our clonoSEQ coverage under Medicare, we bill an episode of treatment when we deliver the first eligible test results. This billing contemplates all necessary tests required during a patient’s treatment cycle, which is currently estimated at approximately four tests per patient, including the initial sequence identification test. Revenue recognition commences at the time the initial billable test result is delivered and is based upon cumulative tests delivered to date. We estimate the number of tests we expect to deliver over a patient’s treatment cycle based on historical testing frequencies for patients by indication. These estimates are subject to change as we develop more information about utilization over time. Any unrecognized revenue from the initial billable test is recorded as deferred revenue and is recognized as we deliver the remaining tests in a patient’s treatment cycle. For research customers, contracts typically include an amount billed in advance of services (“upfront”) and subsequent billings as sample results are delivered to the customer. Upfront amounts received are recorded as deferred revenue, which we recognize as revenue upon satisfaction of performance obligations. We have identified two typical performance obligations under the terms of our research service contracts: sequencing services and related data analysis. We recognize revenue for both identified performance obligations as sample results are delivered to the customer. Development We derive revenue by providing services through development agreements to biopharmaceutical customers who seek access to our immune medicine platform technologies. We generate revenues from the delivery of professional support activities pertaining to the use of our proprietary immunoSEQ and clonoSEQ services in the development of the respective customers’ initiatives. The transaction price for these contracts may consist of a combination of non-refundable upfront fees, separately priced sequencing fees, progress-based milestones and regulatory milestones. The development agreements may include single or multiple performance obligations, depending on the contract. For certain contracts, we may perform services to support the biopharmaceutical customers’ regulatory submissions as part of their registrational trials. These services include regulatory support pertaining to our technology intended to be utilized as part of the submission, development of analytical plans for our sequencing data, participation on joint research committees and assistance in completing a regulatory submission. Generally, these services are not distinct within the context of the contract, and they are accounted for as a single performance obligation. When sequencing services are separately priced customer options, we assess if a material right exists and, if not, the customer option to purchase additional sequencing services is not considered part of the contract. Except for any non-refundable upfront fees, the other forms of compensation represent variable consideration. Variable consideration related to progress - based and regulatory milestones is estimated using the most likely amount method , where variable consideration is constrained until it is probable that a significant reversal of cumulative revenue recognized will not occur. Progress milestones , such as the first sample result delivered or final patient enrollment in a customer trial , are customer dependent and are included in the transaction price when the respective milestone is probable of occurring. Milestone payments that are not within our customers’ control, such as regulatory approvals, are not consider ed probable of being achieved until those approvals are received. Determining whether regulatory milestone payments are probable is an area that requires significant judgment. In making this assessment, we evaluate scientific, clinical, regulatory and other risks, as well as the level of effort and investment required to achieve the respective milestone. The primary method used to estimate standalone selling price for performance obligations is the adjusted market assessment approach. Using this approach, we evaluate the market in which we sell our services and estimate the price that a customer in that market would be willing to pay for our services. We recognize revenue using either an input or output measure of progress that faithfully depicts performance on a contract, depending on the contract. The measure used is dependent on the nature of the service to be provided in each contract. Selecting the measure of progress and estimating progress to date requires significant judgment.
Net Loss Per Share Attributable to Common Shareholders	Net Loss Per Share Attributable to Common Shareholders We calculate basic net loss per share attributable to common shareholders by dividing the net loss attributable to common shareholders by the weighted-average number of shares of common stock outstanding for the period. The diluted net loss per share attributable to common shareholders is computed by giving effect to all potential dilutive common stock equivalents outstanding for the period determined using the treasury stock method. For purposes of this calculation, common stock warrants, stock options and restricted stock units are considered common stock equivalents but have been excluded from the calculation of diluted net loss per share attributable to common shareholders, as their effect is anti-dilutive. Prior to the closing of our initial public offering in July 2019 and the related conversion of our convertible preferred stock into common stock, we calculated our basic and diluted net loss per share attributable to common shareholders in conformity with the two-class method required for companies with participating securities. We considered our convertible preferred stock to be participating securities. In the event a dividend had been declared or paid on common stock, holders of convertible preferred stock would have been entitled to a share of such dividend in proportion to the holders of common stock on an as-if converted basis. Under the two-class method, basic net loss per share attributable to common shareholders is calculated by dividing the net loss attributable to common shareholders by the weighted-average number of shares of common stock outstanding for the period. Net loss attributable to common shareholders is determined by allocating undistributed earnings between common and preferred shareholders. The net loss attributable to common shareholders was not allocated to the convertible preferred stock under the two-class method, as the convertible preferred stock did not have a contractual obligation to share in our losses. The diluted net loss per share attributable to common shareholders was computed by giving effect to all potential dilutive common stock equivalents outstanding for the period determined using the treasury stock method. For purposes of this calculation, convertible preferred stock, convertible preferred stock warrants, common stock warrants, stock options and restricted stock units were considered common stock equivalents but were excluded from the calculation of diluted net loss per share attributable to common shareholders, as their effect was anti-dilutive.
Recently Adopted Accounting Pronouncements	Recently Ad opted In February 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2016-02, Leases , Leases Targeted Improvements Leases In adopting the new standard, we utilized certain practical expedients available. These practical expedients include waiving reassessment of (1) whether any expired or existing contracts are or contain leases; (2) lease classification of expired or existing leases; and (3) initial direct costs for existing leases. We also elected to use hindsight in determining the lease term and in assessing impairment of our ROU assets. Furthermore, we have made a policy decision regarding our real estate leases not to separate nonlease components from lease components, to the extent they are fixed. We have also elected not to record on the balance sheet a lease that has a lease term of twelve months or less and does not contain a purchase option that we are reasonably certain to exercise. The standard had a material impact on our unaudited condensed balance sheets but did not have a material impact on our unaudited condensed statements of operations or unaudited condensed statements of cash flows. The most significant impact was the recognition of $33.0 million and $39.7 million of operating lease ROU assets and liabilities, respectively, and the derecognition of a $36.6 million asset and corresponding liability previously recorded pursuant to build-to-suit lease accounting guidance under ASC 840, which resulted in an increase to retained earnings of $0.1 million. The operating lease ROU assets and liabilities recorded at adoption included the derecognition of $7.3 million of deferred rent recognized as of December 31, 2019, as well as a $0.5 million reclassification of tenant incentive receivables previously recognized in the prepaid expenses and other current assets line item on our balance sheet. Refer to Note 8 of the accompanying notes to our unaudited condensed financial statements for additional information regarding leases. In June 2016, the FASB issued ASU 2016-13, Financial Instruments—Credit Losses Measurement of Credit Losses on Financial Instruments In August 2018, the FASB issued ASU No. 2018-15, Intangibles—Goodwill and Other: Internal-Use Software In December 2019, the FASB issued ASU No. 2019-12, Income Taxes Simplifying the Accounting for Income Taxes

Significant Accounting Polici_3

Significant Accounting Policies (Tables)	9 Months Ended
	Sep. 30, 2020
Accounting Policies [Abstract]
Schedule of Concentrations of Risk Percentage	For each significant customer, revenue as a percentage of total revenue for the periods presented and accounts receivable, net as a percentage of total accounts receivable, net as of the periods presented were as follows: Revenue Accounts Receivable, Net Three Months Ended September 30, Nine Months Ended September 30, September 30, December 31, 2020 2019 2020 2019 2020 2019 Customer A *% 16.0% *% 11.8% 16.4% 41.8% Customer B * 10.7 * * * * Customer C 10.3 * * * 21.4 * Genentech, Inc. 48.1 43.9 55.1 43.7 * * * less than 10%

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2020
Fair Value Disclosures [Abstract]
Summary of Financial Assets and Liabilities Measured at Fair Value on a Recurring Basis	The following tables set forth the fair value of financial assets as of September 30, 2020 and December 31, 2019 that were measured at fair value on a recurring basis (in thousands): September 30, 2020 Level 1 Level 2 Level 3 Total Financial assets Money market funds $ 495,115 $ — $ — $ 495,115 U.S. government debt and agency securities — 340,836 — 340,836 Corporate bonds — 13,634 — 13,634 Total financial assets $ 495,115 $ 354,470 $ — $ 849,585 December 31, 2019 Level 1 Level 2 Level 3 Total Financial assets Money market funds $ 88,683 $ — $ — $ 88,683 Commercial paper — 121,867 — 121,867 U.S. government debt and agency securities — 377,243 — 377,243 Corporate bonds — 86,615 — 86,615 Total financial assets $ 88,683 $ 585,725 $ — $ 674,408

Investments (Tables)

Investments (Tables)	9 Months Ended
	Sep. 30, 2020
Investments Debt And Equity Securities [Abstract]
Schedule of Available-for-sale Investments	Available-for-sale investments consisted of the following as of September 30, 2020 and December 31, 2019 (in thousands): September 30, 2020 Amortized Cost Unrealized Gain Unrealized Loss Estimated Fair Value Short-term marketable securities U.S. government debt and agency securities $ 323,338 $ 1,034 $ (2 ) $ 324,370 Corporate bonds 13,502 134 (2 ) 13,634 Total short-term marketable securities $ 336,840 $ 1,168 $ (4 ) $ 338,004 Long-term marketable securities U.S. government debt and agency securities $ 16,203 $ 263 $ — $ 16,466 Total long-term marketable securities $ 16,203 $ 263 $ — $ 16,466 December 31, 2019 Amortized Cost Unrealized Gain Unrealized Loss Estimated Fair Value Short-term marketable securities Commercial paper $ 121,866 $ — $ — $ 121,866 U.S. government debt and agency securities 285,963 394 (1 ) 286,356 Corporate bonds 71,962 109 (3 ) 72,068 Total short-term marketable securities $ 479,791 $ 503 $ (4 ) $ 480,290 Long-term marketable securities U.S. government debt and agency securities $ 90,750 $ 146 $ (9 ) $ 90,887 Corporate bonds 14,513 35 — 14,548 Total long-term marketable securities $ 105,263 $ 181 $ (9 ) $ 105,435
Schedule of Gross Unrealized Holding Losses and Fair Value for Investments in Unrealized Loss Position	The following table presents the gross unrealized holding losses and fair value for investments in an unrealized loss position, and the length of time that individual securities have been in a continuous loss position, as of September 30, 2020 (in thousands): Less Than 12 Months 12 Months Or Greater Fair Value Unrealized Loss Fair Value Unrealized Loss U.S. government debt and agency securities $ 75,564 $ (2 ) $ — $ — Corporate bonds 1,522 (2 ) — — Total available-for-sale securities $ 77,086 $ (4 ) $ — $ —

Goodwill and Intangible Assets

Goodwill and Intangible Assets (Tables)	9 Months Ended
	Sep. 30, 2020
Goodwill And Intangible Assets Disclosure [Abstract]
Summary of Intangible Assets Subject to Amortization	Intangible assets subject to amortization as of September 30, 2020 and December 31, 2019 consisted of the following (in thousands): September 30, 2020 Gross Carrying Amount Accumulated Amortization Net Carrying Amount Acquired developed technology $ 20,000 $ (9,552 ) $ 10,448 Purchased intellectual property 325 (120 ) 205 Balance at September 30, 2020 $ 20,325 $ (9,672 ) $ 10,653 December 31, 2019 Gross Carrying Amount Accumulated Amortization Net Carrying Amount Acquired developed technology $ 20,000 $ (8,301 ) $ 11,699 Purchased intellectual property 325 (96 ) 229 Balance at December 31, 2019 $ 20,325 $ (8,397 ) $ 11,928
Schedule of Future Amortization Expense for Intangible Assets	As of September 30, 2020, expected future amortization expense for intangible assets was as follows (in thousands): 2020 (excluding the nine months ended September 30, 2020) $ 428 2021 1,699 2022 1,699 2023 1,699 2024 1,703 Thereafter 3,425 Total future amortization expense $ 10,653

Deferred Revenue (Tables)

Deferred Revenue (Tables)	9 Months Ended
	Sep. 30, 2020
Revenue From Contract With Customer [Abstract]
Schedule of Deferred Revenue by Revenue Classification	Deferred revenue by revenue classification as of September 30, 2020 and December 31, 2019 was as follows (in thousands): September 30, 2020 December 31, 2019 Current deferred revenue Sequencing $ 16,040 $ 12,482 Development 62,152 48,512 Total current deferred revenue 78,192 60,994 Non-current deferred revenue Sequencing 637 1,459 Development 174,216 217,873 Total non-current deferred revenue 174,853 219,332 Total current and non-current deferred revenue $ 253,045 $ 280,326
Schedule of Changes in Deferred Revenue	Changes in deferred revenue during the nine months ended September 30, 2020 were as follows (in thousands): Deferred revenue balance at December 31, 2019 $ 280,326 Additions to deferred revenue during the period 19,859 Revenue recognized during the period (47,140 ) Deferred revenue balance at September 30, 2020 $ 253,045

Leases (Tables)

Leases (Tables)	9 Months Ended
	Sep. 30, 2020
Lessee Disclosure [Abstract]
Summary of Oher Information Related to Operating Lease	Other information related to our operating leases as of 30, 2020 was as follows: Weighted-average remaining lease term (in years) 9.66 Weighted-average discount rate 4.6 %
Summary of Reconciles Undiscounted Operating Lease Cash Flows	The following table reconciles our undiscounted operating lease cash flows to our operating lease liabilities as of 30, 2020 (in thousands): 2020 (excluding the nine months ended September 30, 2020) $ 1,532 2021 6,887 2022 6,886 2023 6,450 2024 5,956 Thereafter 30,979 Total undiscounted lease payments 58,690 Less: Imputed interest rate (11,682 ) Tenant improvement receivables (673 ) Total operating lease liabilities $ 46,335 Less: current portion (3,969 ) Operating lease liabilities, less current portion $ 42,366

Shareholders' Equity (Tables)

Shareholders' Equity (Tables)	9 Months Ended
	Sep. 30, 2020
Equity [Abstract]
Summary of Reserved Shares of Common Stock	As of September 30, 2020, we have reserved shares of common stock for the following: Shares issuable upon the exercise of outstanding common stock options and the vesting of outstanding common restricted stock units granted 15,567,900 Shares available for future grant under the 2019 Equity Incentive Plan 18,787,301 Shares available for future grant under the Employee Stock Purchase Plan 2,804,298 Shares to be issued upon exercise of a common stock warrant 56,875 Total shares of common stock reserved for future issuance 37,216,374

Equity Incentive Plans (Tables)

Equity Incentive Plans (Tables)	9 Months Ended
	Sep. 30, 2020
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Summary of Changes in Shares Available for Grant	Changes in shares available for grant during the nine months ended September 30, 2020 were as follows: Shares Available for Grant Shares available for grant at December 31, 2019 15,396,254 2019 Plan reserve increase on January 1, 2020 6,261,907 Options and restricted stock units granted (3,070,331 ) Options and restricted stock units forfeited, cancelled or expired 199,471 Shares available for grant at September 30, 2020 18,787,301
Summary of Stock Option Activity Under 2008 Plan 2009 Plan and 2019 Plan	Stock option activity under the 2008 Plan, 2009 Plan and 2019 Plan during the nine months ended September 30, 2020 was as follows: Shares Subject to Outstanding Options Weighted- Average Exercise Price per Share Aggregate Intrinsic Value (in thousands) Options outstanding at December 31, 2019 16,646,654 $ 6.14 $ 398,379 Options granted 3,020,331 31.98 Options forfeited or cancelled (184,471 ) 14.19 Options expired (15,000 ) 0.16 Options exercised (3,949,614 ) 3.91 Options outstanding at September 30, 2020 15,517,900 $ 11.65 $ 573,922 Options vested and exercisable at September 30, 2020 8,604,883 $ 5.97 $ 367,072
Summary of Estimated Fair Value of Options Granted	The estimated fair value of options granted during the nine months ended September 30, 2020 and 2019 was estimated using the Black-Scholes option-pricing model with the following assumptions: Nine Months Ended September 30, 2020 2019 Grant date fair value $17.68 - $48.54 $7.80 - $47.81 Expected term (in years) 5.27 - 6.08 5.27 - 6.08 Risk-free interest rate 0.4% - 1.7% 1.4% - 2.5% Expected volatility 70.5% - 73.0% 64.3% - 72.9% Expected dividend yield — —
Summary of Compensation Costs Related to Stock Options and RSUs Included on Statements of Operations	The compensation costs related to stock options and RSUs for the three and nine months ended September 30, 2020 and 2019, respectively, are included on our statements of operations as follows (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2020 2019 2020 2019 Cost of revenue $ 206 $ 133 $ 587 $ 376 Research and development 2,216 943 5,912 2,838 Sales and marketing 1,759 798 4,583 2,647 General and administration 2,289 1,461 6,436 3,852 Total share-based compensation expense $ 6,470 $ 3,335 $ 17,518 $ 9,713

Net Loss Per Share Attributab_2

Net Loss Per Share Attributable to Common Shareholders (Tables)	9 Months Ended
	Sep. 30, 2020
Earnings Per Share [Abstract]
Computation of the Basic and Diluted Net Loss Per Share Attributable to Common Shareholders	The following table sets forth the computation of the basic and diluted net loss per share attributable to common shareholders for the three and nine months ended September 30, 2020 and 2019, respectively (in thousands, except share and per share amounts): Three Months Ended September 30, Nine Months Ended September 30, 2020 2019 2020 2019 Net loss $ (36,719 ) $ (13,950 ) $ (101,657 ) $ (47,995 ) Fair value adjustments to redemption value for Series E-1 convertible preferred stock options — — — (964 ) Net loss attributable to common shareholders, basic and diluted $ (36,719 ) $ (13,950 ) $ (101,657 ) $ (48,959 ) Weighted-average shares used in computing net loss per share 134,372,026 124,285,686 129,289,948 50,552,389 Net loss per share attributable to common shareholders, basic and diluted $ (0.27 ) $ (0.11 ) $ (0.79 ) $ (0.97 )
Weighted-Average Common Stock Equivalents were Excluded From Calculation of Diluted Net Loss Per Share Attributable to Common Shareholders	The following weighted-average common stock equivalents were excluded from the calculation of diluted net loss per share attributable to common shareholders for the three and nine months ended September 30, 2020 and 2019, respectively, as they had an anti-dilutive effect: Three Months Ended September 30, Nine Months Ended September 30, 2020 2019 2020 2019 Convertible preferred stock (on as if converted basis) — — — 61,641,506 Stock options issued and outstanding 15,718,821 17,466,409 16,484,334 17,096,516 Unvested restricted stock units 50,000 7,380 34,138 2,487 Common stock warrants 56,875 56,875 56,875 55,653 Convertible preferred stock warrants — — — 37,708 Total 15,825,696 17,530,664 16,575,347 78,833,870

Organization and Description _2

Organization and Description of Business - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands	Jul. 01, 2019	Jul. 31, 2020	Sep. 30, 2020	Sep. 30, 2019
Subsidiary Or Equity Method Investee [Line Items]
Net proceeds from issuance of common stock			$ 272,160	$ 320,850
Initial Public Offering
Subsidiary Or Equity Method Investee [Line Items]
Shares issued	17,250,000
Public offering price	$ 20
Over-allotment Option, at Underwritten Public Offering
Subsidiary Or Equity Method Investee [Line Items]
Shares issued		7,200,000
Public offering price		$ 40
Net proceeds from issuance of common stock		$ 271,800

Significant Accounting Polici_4

Significant Accounting Policies - Additional Information (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2020USD ($)Performance_Obligation	Dec. 31, 2019USD ($)
Significant Accounting Policies [Line Items]
Restricted cash	$ 2,138	$ 2,138
Operating lease right-of-use assets	37,733
Operating lease liabilities	46,335
Accumulated deficit	$ (467,042)	$ (365,478)
ASU 2016-02 (Topic 842)
Significant Accounting Policies [Line Items]
Change in accounting principle, accounting standards update, adoption date	Jan. 1, 2020
Change in accounting principle, accounting standards update, early adoption	false
Change in accounting principle, accounting standards update, adopted	true
Change in accounting principle, accounting standards update, immaterial effect	false
Operating lease right-of-use assets	$ 33,000
Operating lease liabilities	39,700
Derecognition of deferred rent	7,300
Reclassification of tenant incentive receivables	500
Derecognized portion of build-to-suit asset	36,600
Accumulated deficit	$ 100
Accounting Standards Update 2018-15
Significant Accounting Policies [Line Items]
Change in accounting principle, accounting standards update, adoption date	Jan. 1, 2020
Change in accounting principle, accounting standards update, early adoption	false
Change in accounting principle, accounting standards update, adopted	true
Change in accounting principle, accounting standards update, immaterial effect	true
Accounting Standards Update 2019-12
Significant Accounting Policies [Line Items]
Change in accounting principle, accounting standards update, adoption date	Jan. 1, 2020
Change in accounting principle, accounting standards update, early adoption	true
Change in accounting principle, accounting standards update, adopted	true
Change in accounting principle, accounting standards update, immaterial effect	true
Sequencing Revenue
Significant Accounting Policies [Line Items]
Number of revenue performance obligations | Performance_Obligation	2

Significant Accounting Polici_5

Significant Accounting Policies - Schedule of Concentrations of Risk Percentage (Details) - Customer Concentration Risk	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Customer A | Revenue
Significant Accounting Policies [Line Items]
Concentration risk, percentage		16.00%		11.80%
Customer A | Accounts Receivable, Net
Significant Accounting Policies [Line Items]
Concentration risk, percentage			16.40%		41.80%
Customer B | Revenue
Significant Accounting Policies [Line Items]
Concentration risk, percentage		10.70%
Customer C | Revenue
Significant Accounting Policies [Line Items]
Concentration risk, percentage	10.30%
Customer C | Accounts Receivable, Net
Significant Accounting Policies [Line Items]
Concentration risk, percentage			21.40%
Genentech, Inc. | Revenue
Significant Accounting Policies [Line Items]
Concentration risk, percentage	48.10%	43.90%	55.10%	43.70%

Revenue - Additional Informatio

Revenue - Additional Information (Details) - USD ($)	1 Months Ended	3 Months Ended		9 Months Ended
	Feb. 28, 2019	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Disaggregation Of Revenue [Line Items]
Revenue recognized				$ (47,140,000)
Revenue from collaboration agreement		$ 26,299,000	$ 26,058,000	68,197,000	$ 60,862,000
MRD Development Agreements
Disaggregation Of Revenue [Line Items]
Milestone revenue recognized		2,500,000	2,000,000	2,500,000	2,000,000
Revenue recognized		2,600,000	2,300,000	3,100,000	3,100,000
MRD Development Agreements | Maximum
Disaggregation Of Revenue [Line Items]
Additional milestone payment receivable		313,500,000		313,500,000
Genentech Collaboration Agreement
Disaggregation Of Revenue [Line Items]
Non-refundable upfront payments received	$ 300,000,000			300,000,000
Revenue from collaboration agreement		12,300,000	$ 11,400,000	$ 35,900,000	$ 26,200,000
Genentech Collaboration Agreement | Maximum
Disaggregation Of Revenue [Line Items]
Revenue recognition expected period				8 years
Genentech Collaboration Agreement | Maximum | Regulatory Milestones
Disaggregation Of Revenue [Line Items]
Expected revenue through milestone payments		75,000,000		$ 75,000,000
Genentech Collaboration Agreement | Maximum | Development Milestones
Disaggregation Of Revenue [Line Items]
Expected revenue through milestone payments		300,000,000		300,000,000
Genentech Collaboration Agreement | Maximum | Commercial Milestones
Disaggregation Of Revenue [Line Items]
Expected revenue through milestone payments		1,430,000,000		1,430,000,000
Genentech Collaboration Agreement | Minimum
Disaggregation Of Revenue [Line Items]
Expected revenue through milestone payments		$ 1,800,000		$ 1,800,000
Revenue recognition expected period				7 years

Fair Value Measurements - Summa

Fair Value Measurements - Summary of Financial Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) - Recurring basis - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Financial assets
Total financial assets	$ 849,585	$ 674,408
Level 1
Financial assets
Total financial assets	495,115	88,683
Level 2
Financial assets
Total financial assets	354,470	585,725
Money Market Funds
Financial assets
Total financial assets	495,115	88,683
Money Market Funds | Level 1
Financial assets
Total financial assets	495,115	88,683
Commercial Paper
Financial assets
Total financial assets		121,867
Commercial Paper | Level 2
Financial assets
Total financial assets		121,867
U.S. Government Debt and Agency Securities
Financial assets
Total financial assets	340,836	377,243
U.S. Government Debt and Agency Securities | Level 2
Financial assets
Total financial assets	340,836	377,243
Corporate Bonds
Financial assets
Total financial assets	13,634	86,615
Corporate Bonds | Level 2
Financial assets
Total financial assets	$ 13,634	$ 86,615

Investments - Schedule of Avail

Investments - Schedule of Available-for-sale Investments (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Short-Term Marketable Securities
Schedule of Available-for-Sale Securities [Line Items]
Amortized Cost	$ 336,840	$ 479,791
Unrealized Gain	1,168	503
Unrealized Loss	(4)	(4)
Estimated Fair Value	338,004	480,290
Long-Term Marketable Securities
Schedule of Available-for-Sale Securities [Line Items]
Amortized Cost	16,203	105,263
Unrealized Gain	263	181
Unrealized Loss		(9)
Estimated Fair Value	16,466	105,435
Commercial Paper | Short-Term Marketable Securities
Schedule of Available-for-Sale Securities [Line Items]
Amortized Cost		121,866
Estimated Fair Value		121,866
U.S. Government Debt and Agency Securities | Short-Term Marketable Securities
Schedule of Available-for-Sale Securities [Line Items]
Amortized Cost	323,338	285,963
Unrealized Gain	1,034	394
Unrealized Loss	(2)	(1)
Estimated Fair Value	324,370	286,356
U.S. Government Debt and Agency Securities | Long-Term Marketable Securities
Schedule of Available-for-Sale Securities [Line Items]
Amortized Cost	16,203	90,750
Unrealized Gain	263	146
Unrealized Loss		(9)
Estimated Fair Value	16,466	90,887
Corporate Bonds | Short-Term Marketable Securities
Schedule of Available-for-Sale Securities [Line Items]
Amortized Cost	13,502	71,962
Unrealized Gain	134	109
Unrealized Loss	(2)	(3)
Estimated Fair Value	$ 13,634	72,068
Corporate Bonds | Long-Term Marketable Securities
Schedule of Available-for-Sale Securities [Line Items]
Amortized Cost		14,513
Unrealized Gain		35
Estimated Fair Value		$ 14,548

Investments - Additional Inform

Investments - Additional Information (Details) - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Prepaid Expenses and Other Current Assets
Schedule of Available-for-Sale Securities [Line Items]
Accrued interest receivable	$ 1.4	$ 2.2

Investments - Schedule of Gross

Investments - Schedule of Gross Unrealized Holding Losses and Fair Value for Investments in Unrealized Loss Position (Details) $ in Thousands	Sep. 30, 2020USD ($)
Schedule of Available-for-Sale Securities [Line Items]
Less Than 12 Months, Fair Value	$ 77,086
Less Than 12 Months, Unrealized Loss	(4)
U.S. Government Debt and Agency Securities
Schedule of Available-for-Sale Securities [Line Items]
Less Than 12 Months, Fair Value	75,564
Less Than 12 Months, Unrealized Loss	(2)
Corporate Bonds
Schedule of Available-for-Sale Securities [Line Items]
Less Than 12 Months, Fair Value	1,522
Less Than 12 Months, Unrealized Loss	$ (2)

Goodwill and Intangible Asset_2

Goodwill and Intangible Assets - Additional Information (Details) - USD ($)	9 Months Ended
	Sep. 30, 2020	Dec. 31, 2019	Dec. 31, 2015
Goodwill [Line Items]
Goodwill	$ 118,972,000	$ 118,972,000	$ 0
Purchased Intellectual Property
Goodwill [Line Items]
Amortization period of intangible assets	6 years 3 months 18 days

Goodwill and Intangible Asset_3

Goodwill and Intangible Assets - Summary of Intangible Assets Subject to Amortization (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Finite Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 20,325	$ 20,325
Accumulated Amortization	(9,672)	(8,397)
Net Carrying Amount	10,653	11,928
Acquired Developed Technology
Finite Lived Intangible Assets [Line Items]
Gross Carrying Amount	20,000	20,000
Accumulated Amortization	(9,552)	(8,301)
Net Carrying Amount	10,448	11,699
Purchased Intellectual Property
Finite Lived Intangible Assets [Line Items]
Gross Carrying Amount	325	325
Accumulated Amortization	(120)	(96)
Net Carrying Amount	$ 205	$ 229

Goodwill and Intangible Asset_4

Goodwill and Intangible Assets - Schedule of Future Amortization Expense for Intangible Assets (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Goodwill And Intangible Assets Disclosure [Abstract]
2020 (excluding the nine months ended September 30, 2020)	$ 428
2021	1,699
2022	1,699
2023	1,699
2024	1,703
Thereafter	3,425
Net Carrying Amount	$ 10,653	$ 11,928

Deferred Revenue - Schedule of

Deferred Revenue - Schedule of Deferred Revenue by Revenue Classification (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Current deferred revenue
Total current deferred revenue	$ 78,192	$ 60,994
Non-current deferred revenue
Total non-current deferred revenue	174,853	219,332
Total current and non-current deferred revenue	253,045	280,326
Sequencing Revenue
Current deferred revenue
Total current deferred revenue	16,040	12,482
Non-current deferred revenue
Total non-current deferred revenue	637	1,459
Development Revenue
Current deferred revenue
Total current deferred revenue	62,152	48,512
Non-current deferred revenue
Total non-current deferred revenue	$ 174,216	$ 217,873

Deferred Revenue - Additional I

Deferred Revenue - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2020	Dec. 31, 2019
Disaggregation Of Revenue [Line Items]
Current deferred revenue	$ 78,192	$ 78,192	$ 60,994
Deferred revenue, less current portion	174,853	174,853	219,332
Revenue recognized		(47,140)
Deferred Revenue
Disaggregation Of Revenue [Line Items]
Revenue recognized		41,900
Development Revenue
Disaggregation Of Revenue [Line Items]
Current deferred revenue	62,152	62,152	48,512
Deferred revenue, less current portion	174,216	174,216	217,873
Development Revenue | Genentech, Inc.
Disaggregation Of Revenue [Line Items]
Current deferred revenue	59,900	59,900	48,100
Deferred revenue, less current portion	169,100	169,100	216,800
Sequencing Revenue
Disaggregation Of Revenue [Line Items]
Current deferred revenue	16,040	16,040	12,482
Deferred revenue, less current portion	637	637	$ 1,459
Revenue recognized	$ 500	$ 900

Deferred Revenue - Additional_2

Deferred Revenue - Additional Information (Details1) - Genentech, Inc. - Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2020-10-01	Sep. 30, 2020
Disaggregation Of Revenue [Line Items]
Deferred revenue, expected to be recognized	12 months
Minimum
Disaggregation Of Revenue [Line Items]
Deferred revenue, expected to be recognized	6 years
Maximum
Disaggregation Of Revenue [Line Items]
Deferred revenue, expected to be recognized	7 years

Deferred Revenue - Schedule o_2

Deferred Revenue - Schedule of Changes in Deferred Revenue (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2020USD ($)
Revenue From Contract With Customer [Abstract]
Deferred revenue balance at December 31, 2019	$ 280,326
Additions to deferred revenue during the period	19,859
Revenue recognized during the period	(47,140)
Deferred revenue balance at September 30, 2020	$ 253,045

Leases- Additional Information

Leases- Additional Information (Details) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020USD ($)ft²	Sep. 30, 2019USD ($)	Sep. 30, 2020USD ($)ft²Lease	Sep. 30, 2019USD ($)	Aug. 31, 2019USD ($)ft²
Lessee Lease Description [Line Items]
Number of square feet | ft²	19,867		19,867		100,000
Tenant improvement allowance and commenced			$ 0.6
Operating lease option to extend			options to extend certain of the leases up to 10.0 years
Lessee, Operating Lease, Existence of Option to Extend			true
Operating lease renewal term	10 years		10 years
Operating lease termination period			3 years
Number of operating lease terminate | Lease			2
Operating lease expense	$ 1.4		$ 3.7
Operating lease variable lease expense	0.7		1.8
Rent expenses		$ 1.3		$ 3.6
Cash paid for amounts included in measurement of lease liabilities, net of tenant improvement allowances received			1.8
Cash received for tenant improvement allowances			1.8
Letter of credit					$ 2.1
Operating lease, lease liability upon lease commencement	$ 89.8		$ 89.8
Operating lease, term of contract upon lease commencement	12 years 8 months 12 days		12 years 8 months 12 days
Other Long-term Liabilities
Lessee Lease Description [Line Items]
Tenant improvement costs relating to-be-constructed building	$ 2.4		$ 2.4
Prepaid Expenses and Other Current Assets
Lessee Lease Description [Line Items]
Tenant improvement costs receivable	$ 2.4		$ 2.4
Minimum
Lessee Lease Description [Line Items]
Operating lease remaining lease term	1 year 7 months 6 days		1 year 7 months 6 days
Maximum
Lessee Lease Description [Line Items]
Operating lease remaining lease term	11 years 9 months 18 days		11 years 9 months 18 days

Leases- Summary of Oher Informa

Leases- Summary of Oher Information Related to Operating Lease (Details)	Sep. 30, 2020
Lessee Disclosure [Abstract]
Weighted-average remaining lease term (in years)	9 years 7 months 28 days
Weighted-average discount rate	4.60%

Leases- Summary of Reconciles U

Leases- Summary of Reconciles Undiscounted Operating Lease Cash Flows (Details) $ in Thousands	Sep. 30, 2020USD ($)
Lessee Disclosure [Abstract]
2020 (excluding the nine months ended September 30, 2020)	$ 1,532
2021	6,887
2022	6,886
2023	6,450
2024	5,956
Thereafter	30,979
Total undiscounted lease payments	58,690
Imputed interest rate	(11,682)
Tenant improvement receivables	(673)
Total operating lease liabilities	46,335
Less: current portion	(3,969)
Operating lease liabilities, less current portion	$ 42,366

Shareholders' Equity - Addition

Shareholders' Equity - Additional Information (Details)	Jan. 01, 2020shares	Jun. 30, 2019shares	Sep. 30, 2020Vote$ / sharesshares	Dec. 31, 2014$ / sharesshares	Dec. 31, 2019$ / sharesshares	Dec. 31, 2018shares
Class Of Stock [Line Items]
Preferred stock, shares authorized			10,000,000		10,000,000
Preferred stock, par value | $ / shares			$ 0.0001		$ 0.0001
Preferred stock, shares outstanding			0		0
Common stock authorized			340,000,000		340,000,000
Common stock par value | $ / shares			$ 0.0001		$ 0.0001
Common stock voting rights description			Holders of our common stock are entitled to one vote for each share of common stock held
Number of vote for each share | Vote			1
Common stock outstanding			136,392,256		125,238,142
Warrant issued to purchase stock			56,875
Series C Convertible Preferred Stock
Class Of Stock [Line Items]
Warrant issued to purchase stock				56,875
Warrant exercisable term				7 years
Weighted-average exercise price of warrants | $ / shares				$ 2.64
Employee Stock Purchase Plan
Class Of Stock [Line Items]
Increase in share reserve	1,252,381
Maximum | Employee Stock Purchase Plan
Class Of Stock [Line Items]
Percentage of annual increases in number of shares	1.00%
2019 Equity Incentive Plan
Class Of Stock [Line Items]
Increase in share reserve	6,261,907
2019 Equity Incentive Plan | Maximum
Class Of Stock [Line Items]
Percentage of annual increases in number of shares	5.00%
Convertible Preferred Stock
Class Of Stock [Line Items]
Conversion of convertible preferred stock		93,039,737
Convertible preferred stock outstanding		93,039,737	0			92,790,094

Shareholders' Equity - Summary

Shareholders' Equity - Summary of Reserved Shares of Common Stock (Details)	Sep. 30, 2020shares
Class Of Stock [Line Items]
Total shares of common stock reserved for future issuance	37,216,374
Exercise of Outstanding Common Stock Options and Vesting of Outstanding Common Restricted Stock Units Granted
Class Of Stock [Line Items]
Total shares of common stock reserved for future issuance	15,567,900
Grant | 2019 Equity Incentive Plan
Class Of Stock [Line Items]
Total shares of common stock reserved for future issuance	18,787,301
Grant | Employee Stock Purchase Plan
Class Of Stock [Line Items]
Total shares of common stock reserved for future issuance	2,804,298
Exercise of Common Stock Warrant
Class Of Stock [Line Items]
Total shares of common stock reserved for future issuance	56,875

Equity Incentive Plans - Additi

Equity Incentive Plans - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Weighted-average remaining contractual life options outstanding			7 years 1 month 6 days
Weighted-average remaining contractual life vested and exercisable options outstanding			5 years 10 months 24 days
Proceeds from exercise of stock options			$ 15,495	$ 2,307
Proceeds from settlement of stock option exercised in prior periods			$ 500
Weighted-average volatility			71.20%	68.00%
Share-based compensation expense	$ 6,470	$ 3,335	$ 17,518	$ 9,713
Unrecognized share-based compensation expense related to unvested stock options	75,500		$ 75,500
Unrecognized share-based compensation expense related to unvested stock options, weighted-average period for recognition			3 years 1 month 6 days
Option Valuation Model
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected dividend yield			0.00%
Restricted Stock Units
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized share-based compensation expense related to unvested stock options, weighted-average period for recognition			3 years 6 months
Unrecognized share-based compensation expense related to unvested RSUs	$ 1,200		$ 1,200
Sequenta 2008 Stock Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares available for future issuance	0		0
Equity awards outstanding	0		0
2009 Equity Incentive Plan | Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares available for future issuance	0		0
2009 Equity Incentive Plan | Options | Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Option expiration period			10 years
2019 Equity Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares available for future issuance	18,787,301		18,787,301		15,396,254
2019 Equity Incentive Plan | Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares authorized for issuance	22,102,754		22,102,754
2019 Equity Incentive Plan | Options | Non Employee Directors
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting period			4 years
2019 Equity Incentive Plan | Options | Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Option expiration period			10 years
2019 Equity Incentive Plan | Restricted Stock Units
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based compensation granted shares vested			4,500
Weighted-average grant date fair value per share			$ 41.63
Share-based compensation nonvested and outstanding shares	50,000		50,000		4,500
Weighted-average grant date fair value per share nonvested and outstanding	$ 28.10		$ 28.10		$ 41.63
Share-based compensation, nonvested and outstanding granted			50,000
2019 Equity Incentive Plan | Restricted Stock Units | Prepaid Expenses and Other Current Assets
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unsettled cash proceeds related to stock options exercised	$ 400		$ 400

Equity Incentive Plans - Summar

Equity Incentive Plans - Summary of Changes in Shares Available for Grant (Details) - 2019 Equity Incentive Plan	9 Months Ended
	Sep. 30, 2020shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares Available for Grant, Outstanding, Beginning Balance	15,396,254
Shares Available for Grant, 2019 Plan reserve increase	6,261,907
Shares Available for Grant, Options and restricted stock units granted	(3,070,331)
Shares Available for Grant, Options and restricted stock units forfeited, cancelled or expired	199,471
Shares Available for Grant, Outstanding, Ending Balance	18,787,301

Equity Incentive Plans - Summ_2

Equity Incentive Plans - Summary of Stock Option Activity Under 2008 Plan 2009 Plan and 2019 Plan (Details) $ / shares in Units, $ in Thousands	9 Months Ended
	Sep. 30, 2020USD ($)$ / sharesshares	Dec. 31, 2019USD ($)
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Shares Subject to Outstanding Options, Options outstanding, Beginning Balance | shares	16,646,654
Shares Subject to Outstanding Options, Options granted | shares	3,020,331
Shares Subject to Outstanding Options, Options forfeited or cancelled | shares	(184,471)
Shares Subject to Outstanding Options, Options expired | shares	(15,000)
Shares Subject to Outstanding Options, Options exercised | shares	(3,949,614)
Shares Subject to Outstanding Options, Options outstanding, Ending Balance | shares	15,517,900
Shares Subject to Outstanding Options, Options vested and exercisable | shares	8,604,883
Weighted Average Exercise Price per Share, Options outstanding, Beginning Balance | $ / shares	$ 6.14
Weighted Average Exercise Price per Share, Options granted | $ / shares	31.98
Weighted Average Exercise Price per Share, Options forfeited or cancelled | $ / shares	14.19
Weighted Average Exercise Price per Share, Options expired | $ / shares	0.16
Weighted Average Exercise Price per Share, Options exercised | $ / shares	3.91
Weighted Average Exercise Price per Share, Options outstanding, Ending Balance | $ / shares	11.65
Weighted Average Exercise Price per Share, Options vested and exercisable | $ / shares	$ 5.97
Aggregate Intrinsic Value, Option outstanding | $	$ 573,922	$ 398,379
Aggregate Intrinsic Value, Options vested and exercisable | $	$ 367,072

Equity Incentive Plans - Summ_3

Equity Incentive Plans - Summary of Estimated Fair Value of Options Granted (Details) - $ / shares	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Risk-free interest rate, minimum	0.40%	1.40%
Risk-free interest rate, maximum	1.70%	2.50%
Expected volatility, minimum	70.50%	64.30%
Expected volatility, maximum	73.00%	72.90%
Minimum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Grant date fair value	$ 17.68	$ 7.80
Expected term (in years)	5 years 3 months 7 days	5 years 3 months 7 days
Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Grant date fair value	$ 48.54	$ 47.81
Expected term (in years)	6 years 29 days	6 years 29 days

Equity incentive Plans - Summ_4

Equity incentive Plans - Summary of Compensation Costs Related to Stock Options and RSUS Included on Statements of Operations (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based compensation expense	$ 6,470	$ 3,335	$ 17,518	$ 9,713
Cost of Revenue
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based compensation expense	206	133	587	376
Research and Development
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based compensation expense	2,216	943	5,912	2,838
Sales and Marketing
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based compensation expense	1,759	798	4,583	2,647
General and Administration
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based compensation expense	$ 2,289	$ 1,461	$ 6,436	$ 3,852

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details) - USD ($)	3 Months Ended	9 Months Ended	12 Months Ended
	Sep. 30, 2020	Sep. 30, 2020	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Effective tax expense (benefit)	$ 688,000	$ (1,116,000)	$ 0
CARES ACT 2020 aid net operating losses carryforward period		5 years

Net Loss Per Share Attributab_3

Net Loss Per Share Attributable to Common Shareholders - Computation of the Basic and Diluted Net Loss Per Share Attributable to Common Shareholders (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Earnings Per Share [Abstract]
Net loss	$ (36,719)	$ (13,950)	$ (101,657)	$ (47,995)
Fair value adjustments to redemption value for Series E-1 convertible preferred stock options				(964)
Net loss attributable to common shareholders	$ (36,719)	$ (13,950)	$ (101,657)	$ (48,959)
Weighted-average shares used in computing net loss per share	134,372,026	124,285,686	129,289,948	50,552,389
Net loss per share attributable to common shareholders, basic and diluted	$ (0.27)	$ (0.11)	$ (0.79)	$ (0.97)

Net Loss Per Share Attributab_4

Net Loss Per Share Attributable to Common Shareholders - Weighted-Average Common Stock Equivalents were Excluded From Calculation of Diluted Net Loss Per Share Attributable to Common Shareholders (Details) - shares	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities	15,825,696	17,530,664	16,575,347	78,833,870
Convertible Preferred Stock
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities				61,641,506
Options
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities	15,718,821	17,466,409	16,484,334	17,096,516
Unvested Restricted Stock Units
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities	50,000	7,380	34,138	2,487
Common Stock Warrants
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities	56,875	56,875	56,875	55,653
Convertible Preferred Stock Warrants
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities				37,708