Veracyte (VCYT) 10-K22 Feb 212020 FY Annual reportFinancial data

Company Profile

Cover Page

Cover Page - USD ($) $ in Billions	12 Months Ended
Cover Page - USD ($) $ in Billions	Dec. 31, 2020	Feb. 19, 2021	Jun. 30, 2020
Cover [Abstract]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2020
Current Fiscal Year End Date	--12-31
Document Transition Report	false
Entity File Number	001-36156
Entity Registrant Name	VERACYTE, INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	20-5455398
Entity Address, Address Line One	6000 Shoreline Court,
Entity Address, Address Line Two	Suite 300
Entity Address, City or Town	South San Francisco,
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	94080
City Area Code	650
Local Phone Number	243-6300
Title of 12(b) Security	Common Stock, par value, $0.001 per share
Trading Symbol	VCYT
Security Exchange Name	NASDAQ
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	true
Entity Shell Company	false
Entity Public Float			$ 1.3
Entity Common Stock, Shares Outstanding (in shares)		67,001,496
Documents Incorporated by Reference	DOCUMENTS INCORPORATED BY REFERENCE Portions of the registrant's proxy statement to be filed with the Securities and Exchange Commission in connection with the solicitation of proxies for the registrant's 2021 Annual Meeting of Stockholders to be held on or about June 7, 2021 are incorporated herein by reference in Part III of this Annual Report on Form 10-K to the extent stated herein. Such proxy statement will be filed with the Securities and Exchange Commission within 120 days of the registrant’s fiscal year ended December 31, 2020.
Entity Central Index Key	0001384101
Amendment Flag	false
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	FY

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Current assets:
Cash and cash equivalents	$ 349,364	$ 159,317
Accounts receivable	18,461	19,329
Supplies	4,657	6,806
Prepaid expenses and other current assets	3,197	2,235
Total current assets	375,679	187,687
Property and equipment, net	8,990	8,933
Right-of-use assets - operating lease	7,843	8,808
Finite-lived intangible assets, net	59,924	65,019
Goodwill	2,725	2,725
Restricted cash	603	603
Other assets	1,399	1,437
Total assets	457,163	275,212
Current liabilities:
Accounts payable	3,116	2,328
Accrued liabilities	11,705	13,734
Current portion of deferred revenue	371	0
Current portion of operating lease liability	1,589	1,407
Total current liabilities	16,781	17,469
Long-term debt	810	694
Deferred revenue, net of current portion	829	0
Acquisition related contingent consideration	7,594	6,088
Operating lease liability, net of current portion	9,917	11,506
Total liabilities	35,931	35,757
Commitments and contingencies
Stockholders' equity:
Preferred stock, $0.001 par value; 5,000,000 shares authorized, no shares issued and outstanding as of December 31, 2020 and 2019	0	0
Common stock, $0.001 par value; 125,000,000 shares authorized, 58,200,526 and 49,625,341 shares issued and outstanding as of December 31, 2020 and 2019, respectively	58	50
Additional paid-in capital	702,768	486,090
Accumulated deficit	(281,594)	(246,685)
Total stockholders' equity	421,232	239,455
Total liabilities and stockholders' equity	$ 457,163	$ 275,212

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2020	Dec. 31, 2019
Statement of Financial Position [Abstract]
Preferred stock, par value (in USD per share)	$ 0.001	$ 0.001
Preferred stock, shares authorized (in shares)	5,000,000	5,000,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Common stock, par value (in USD per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	125,000,000	125,000,000
Common stock, shares issued (in shares)	58,200,526	49,625,341
Common stock, shares outstanding (in shares)	58,200,526	49,625,341

Consolidated Statements of Oper

Consolidated Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Total revenue	$ 117,483	$ 120,368	$ 92,008
Operating Expenses:
Research and development	17,204	14,851	14,820
Selling and marketing	52,389	53,691	41,313
General and administrative	36,729	29,029	23,963
Intangible asset amortization	5,095	1,401	1,067
Total operating expenses	152,872	135,495	114,241
Loss from operations	(35,389)	(15,127)	(22,233)
Interest expense	(229)	(677)	(1,963)
Other income, net	709	3,205	1,197
Net loss and comprehensive loss	$ (34,909)	$ (12,599)	$ (22,999)
Net loss per common share, basic and diluted (in USD per share)	$ (0.66)	$ (0.27)	$ (0.62)
Shares use to compute net loss per common share, basic and diluted (in shares)	53,239,231	46,138,177	37,020,246
Testing
Total revenue	$ 101,970	$ 107,355	$ 91,058
Operating Expenses:
Cost of revenue	35,913	36,077	33,078
Product
Total revenue	9,845	923	0
Operating Expenses:
Cost of revenue	4,921	446	0
Biopharmaceutical
Total revenue	5,668	8,090	950
Operating Expenses:
Cost of revenue	621	0	0
Collaboration
Total revenue	$ 0	$ 4,000	$ 0

Consolidated Statements of Stoc

Consolidated Statements of Stockholders' Equity - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Deficit
Beginning balance (in shares) at Dec. 31, 2017		34,210
Beginning balance at Dec. 31, 2017	$ 37,225	$ 34	$ 248,278	$ (211,087)
Increase (Decrease) in Stockholders' Equity [Rollforward]
Sale of common stock in a public offering, net of offering costs (in shares)		5,750
Sale of common stock in a public offering, net of offering costs	55,038	$ 6	55,032
Issuance of common stock on exercise of stock options and vesting of restricted stock units (in shares)		756
Issuance of common stock on exercise of stock options and vesting of restricted stock units	3,463	$ 1	3,462
Issuance of common stock under employee stock purchase plan (ESPP) (in shares)		147
Issuance of common stock under employee stock purchase plan (ESPP)	790		790
Tax portion of vested restricted stock units	(30)		(30)
Stock-based compensation expense (employee)	5,602		5,602
Stock-based compensation expense (non-employee)	24		24
Stock-based compensation expense (ESPP)	332		332
Legal settlement from short-swing profits, net of tax	310		310
Net loss and comprehensive loss	(22,999)			(22,999)
Ending balance (in shares) at Dec. 31, 2018		40,863
Ending balance at Dec. 31, 2018	79,755	$ 41	313,800	(234,086)
Increase (Decrease) in Stockholders' Equity [Rollforward]
Sale of common stock in a public offering, net of offering costs (in shares)		6,325
Sale of common stock in a public offering, net of offering costs	137,848	$ 6	137,842
Issuance of common stock on exercise of stock options and vesting of restricted stock units (in shares)		1,924
Issuance of common stock on exercise of stock options and vesting of restricted stock units	14,355	$ 2	14,353
Issuance of common stock under employee stock purchase plan (ESPP) (in shares)		136
Issuance of common stock under employee stock purchase plan (ESPP)	1,266		1,266
Issuance of common stock for acquisition (in shares)		377
Issuance of common stock for acquisition	10,000	$ 1	9,999
Tax portion of vested restricted stock units	(977)		(977)
Stock-based compensation expense (employee)	8,883		8,883
Stock-based compensation expense (non-employee)	181		181
Stock-based compensation expense (ESPP)	743		743
Net loss and comprehensive loss	(12,599)			(12,599)
Ending balance (in shares) at Dec. 31, 2019		49,625
Ending balance at Dec. 31, 2019	239,455	$ 50	486,090	(246,685)
Increase (Decrease) in Stockholders' Equity [Rollforward]
Sale of common stock in a public offering, net of offering costs (in shares)		6,900
Sale of common stock in a public offering, net of offering costs	193,831	$ 7	193,824
Issuance of common stock on exercise of stock options and vesting of restricted stock units (in shares)		1,573
Issuance of common stock on exercise of stock options and vesting of restricted stock units	11,668	$ 1	11,667
Issuance of common stock under employee stock purchase plan (ESPP) (in shares)		103
Issuance of common stock under employee stock purchase plan (ESPP)	2,037		2,037
Tax portion of vested restricted stock units	(3,845)		(3,845)
Stock-based compensation expense (employee)	12,017		12,017
Stock-based compensation expense (non-employee)	51		51
Stock-based compensation expense (ESPP)	927		927
Net loss and comprehensive loss	(34,909)			(34,909)
Ending balance (in shares) at Dec. 31, 2020		58,201
Ending balance at Dec. 31, 2020	$ 421,232	$ 58	$ 702,768	$ (281,594)

Consolidated Statements of St_2

Consolidated Statements of Stockholders' Equity (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Statement of Stockholders' Equity [Abstract]
Issuance costs	$ 13,169	$ 9,208	$ 3,890

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Operating activities
Net loss	$ (34,909)	$ (12,599)	$ (22,999)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	7,944	4,117	3,920
Gain on disposal of property and equipment	0	(23)	0
Stock-based compensation	12,995	9,807	5,958
Other income	0	0	(93)
Amortization and write-off of debt discount and issuance costs	0	83	32
Interest on end-of-term debt obligation	216	229	312
Write-down of excess supplies	1,088	0	0
Noncash lease expense	964	1,034	0
Revaluation of acquisition-related contingent consideration	1,506	0	0
Impairment loss	1,000	0	0
Effect of foreign currency on operations	(34)	0	0
Changes in operating assets and liabilities:
Accounts receivable	955	(6,161)	(452)
Supplies	1,061	(3,404)	1,922
Prepaid expenses and other current assets	(970)	154	(517)
Other assets	37	(351)	(760)
Operating lease liability	(1,407)	(1,205)	0
Accounts payable	711	(141)	(1,568)
Accrued liabilities, deferred revenue and deferred rent	(868)	5,228	724
Net cash used in operating activities	(9,711)	(3,232)	(13,521)
Investing activities
Purchases of property and equipment	(2,837)	(2,756)	(1,874)
Purchase of equity securities	(1,000)	0	0
Cash paid for acquisition	0	(40,000)	0
Proceeds from the sale of property and equipment	0	23	0
Net cash used in investing activities	(3,837)	(42,733)	(1,874)
Financing activities
Proceeds from issuance of common stock in a public offering, net of issuance costs	193,831	137,848	55,038
Payment of long-term debt	(100)	(24,900)	0
Proceeds from legal settlement regarding short-swing profits	0	0	403
Payment of financial lease liability	0	(308)	(292)
Payment of taxes on vested restricted stock units	(3,845)	(977)	(30)
Proceeds from the exercise of common stock options and employee stock purchases	13,709	15,624	4,380
Net cash provided by financing activities	203,595	127,287	59,499
Net increase in cash, cash equivalents and restricted cash	190,047	81,322	44,104
Cash, cash equivalents and restricted cash at beginning of year	159,920	78,598	34,494
Cash, cash equivalents and restricted cash at end of year	349,967	159,920	78,598
Supplementary cash flow information of non-cash investing and financing activities:
Shares issued for purchase consideration for a business combination	0	10,000	0
Deferred purchase consideration for a business combination	0	6,088	0
Purchases of property and equipment included in accounts payable and accrued liabilities	294	226	273
Supplementary cash flow information:
Cash paid for interest on debt	13	332	1,547
Cash paid for tax	112	35	79
Total cash, cash equivalents and restricted cash	$ 159,920	$ 78,598	$ 78,598

Organization and Description of

Organization and Description of Business	12 Months Ended
Organization and Description of Business	Dec. 31, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization and Description of Business	Organization and Description of Business Veracyte, Inc. (“Veracyte” or the “Company”) is a global genomic diagnostics company that improves patient care by providing answers to clinical questions to inform diagnosis and treatment decisions throughout the patient journey in cancer and other diseases. The Company’s growing menu of genomic tests leverage advances in genomic science and technology to change care for patients, enabling them to avoid risky, costly procedures and quicken time to appropriate treatment. With Veracyte’s exclusive global access to the nCounter Analysis System, the Company is positioned to deliver its tests to patients worldwide through laboratories and hospitals that can perform the tests locally. Veracyte was incorporated in the state of Delaware on August 15, 2006 as Calderome, Inc. Calderome operated as an incubator until early 2008. On March 4, 2008, the Company changed its name to Veracyte, Inc. The Company’s operations are based in South San Francisco, California and Austin, Texas, and it operates in one segment. The Company offers genomic tests in four disease areas: thyroid cancer; lung cancer; idiopathic pulmonary fibrosis, or IPF, and breast cancer. Thyroid Cancer - Afirma Genomic Sequencing Classifier and Xpression Atlas. The Company's Afirma offerings comprise the Afirma GSC and Xpression Atlas, or Afirma XA, which help guide next steps for patients with potentially cancerous thyroid nodules. The offerings are intended to provide physicians with clinically actionable results from a single fine needle aspiration, or FNA, biopsy. The Afirma GSC was developed with RNA whole-transcriptome sequencing and machine learning, and is used to identify patients with benign thyroid nodules among those with indeterminate cytopathology results in order to rule out unnecessary thyroid surgery. The Afirma XA complements the Afirma GSC by providing genomic alteration content from the same FNA samples used in Afirma GSC testing to help physicians decide with greater confidence on the surgical or therapeutic pathway for their patients. The Company commercially launched the Afirma XA in 2018 and in April 2020 introduced an expanded version of the test, which includes significantly more genomic content. Lung Cancer - Percepta Genomic Sequencing Classifier. The Percepta classifier improves lung cancer diagnosis when diagnostic bronchoscopy results are inconclusive. This second-generation test was developed using the Company's RNA whole-transcriptome sequencing and machine learning platform and was commercially introduced in June 2019. The Percepta classifier identifies patients with lung nodules who are at low risk of cancer and may avoid further, invasive procedures as well as patients at high risk of cancer so they may obtain faster diagnosis and treatment. The test is built upon foundational "field of injury" science - through which genomic changes associated with lung cancer in current and former smokers can be identified with a simple brushing of a person's airway - without the need to sample the often hard-to-reach nodule directly. IPF - Envisia Genomic Classifier. The Envisia classifier improves diagnosis of IPF by helping physicians better differentiate IPF from other interstitial lung diseases, or ILDs, without the need for surgery. The test identifies the genomic pattern of usual interstitial pneumonia, or UIP, a hallmark of IPF, with high accuracy on patient samples that are obtained through transbronchial biopsy, a nonsurgical procedure that is commonly used in lung evaluation. Breast Cancer - Prosigna Breast Cancer Prognostic Gene Signature Assay . The Prosigna test, acquired in December 2019 through the Company's strategic transaction with NanoString Technologies, Inc., or NanoString, uses advanced genomic technology to inform next steps for patients with early-stage breast cancer, based on the genomic make-up of their disease. The test uses a set of 50 genes known as the PAM50 gene signature and can provide a breast cancer patient and physician with a prognostic score that indicates the probability of cancer recurrence over ten years. Physicians use Prosigna to help guide therapeutic decisions so that patients receive a therapeutic intervention, such as chemotherapy, only if clinically warranted. Patient test results outside of the United States include intrinsic breast cancer subtypes to complement the risk-of-recurrence score. The Company performs its genomic tests for thyroid cancer, lung cancer and IPF in its CLIA-certified laboratory in South San Francisco, California. In December 2019, the Company acquired from NanoString the exclusive global diagnostics license to the nCounter Analysis System and the Prosigna breast cancer prognostic gene signature assay, which is commercially available, and the LymphMark lymphoma subtyping assay, which is in development. Both tests are designed for use on the nCounter Analysis System. The Prosigna test kits and associated products are sold to laboratories and hospitals in global markets. The Company’s approach also provides multiple opportunities for partnerships with biopharmaceutical and diagnostic testing companies. In developing its products, the Company has built or gained access to unique biorepositories, proprietary technology and bioinformatics that it believes are important to the development of new targeted therapies, determining clinical trial eligibility and guiding treatment selection. Additionally, the Company believes that the nCounter Analysis System provides an attractive distributed platform for other diagnostic companies seeking to make their genomic tests available to global markets.

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
Summary of Significant Accounting Policies	Dec. 31, 2020
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies Basis of Presentation The Company's consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States ("U.S. GAAP"). The consolidated financial statements include the accounts of the Company and its wholly-owned subsidiary, which was created in 2019 to process certain administrative functions associated with the business combination in Note 4. Business Combination. All intercompany accounts and transactions have been eliminated in consolidation. Reclassifications Certain prior period balances have been reclassified to conform to current period presentation of the Company’s consolidated financial statements and accompanying notes. Such reclassifications have no effect on previously reported results of operations, accumulated deficit, subtotals of operating, investing or financing cash flows or consolidated balance sheet totals; however, for the year ended December 31, 2019, the Company reclassified $1.0 million of changes in operating assets and liabilities to noncash lease expense in the statement of cash flows. Use of Estimates The preparation of consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent liabilities as of the date of the consolidated financial statements and the reported amounts of revenue and expenses during the reporting period. Significant items subject to such estimates include: revenue recognition; write-down of supplies; the useful lives of property and equipment; the recoverability of long-lived assets; the incremental borrowing rate for leases; the estimation of the fair value of intangible assets and contingent consideration; variable interest entity assessment; impairment of equity investment, at cost; stock options; income tax uncertainties, including a valuation allowance for deferred tax assets; reserve on accounts receivable and contingencies. The Company bases these estimates on historical and anticipated results, trends, and various other assumptions that the Company believes are reasonable under the circumstances, including assumptions as to future events. These estimates form the basis for making judgments about the carrying values of assets and liabilities and recognized revenue and expenses that are not readily apparent from other sources. Actual results could differ from those estimates and assumptions. Liquidity The Company has incurred net losses since its inception and as of December 31, 2020, the Company had an accumulated deficit of $281.6 million. The Company believes its cash and cash equivalents of $349.4 million as of December 31, 2020, its February 2021 equity offering, and its revenue from sales in 2021 will be sufficient to meet its anticipated cash requirements through at least February 2022. In February 2021, we entered into an agreement to acquire Decipher Biosciences, Inc., or Decipher, for $600 million in cash. See Note 15. Subsequent Events for more information on the acquisition. On February 9, 2021, the Company issued and sold 8,547,297 shares of common stock in a registered public offering, including 1,114,864 shares issued and sold upon the underwriters' exercise in full of their option to purchase additional shares, at a price to the public of $74.00 per share. The Company's net proceeds from the offering were $593.8 million, after deducting underwriting commissions and offering expenses of $38.7 million. In August 2020, the Company issued and sold 6,900,000 shares of common stock in a registered public offering, including 900,000 shares issued and sold upon the underwriters' exercise in full of their option to purchase additional shares, at a price to the public of $30.00 per share. The Company's net proceeds from the offering were approximately $193.8 million, after deducting underwriting commissions and offering expenses of $13.2 million. In May 2019, the Company issued and sold 6,325,000 shares of common stock in a registered public offering, including 825,000 shares issued and sold upon the underwriters' exercise in full of their option to purchase additional shares, at a price to the public of $23.25 per share. The Company's net proceeds from the offering were approximately $137.8 million, after deducting underwriting commissions and offering expenses of $9.2 million. In July 2018, the Company issued and sold 5,750,000 shares of common stock in a registered public offering, including 750,000 shares issued and sold upon the underwriters' exercise in full of their option to purchase additional shares, at a price to the public of $10.25 per share. The Company's net proceeds from the offering were approximately $55.0 million, after deducting underwriting commissions and offering expenses of $3.9 million. In November 2017, the Company entered into a Loan and Security Agreement and drew down a term loan advance of $25.0 million of which the entire amount was used to pay the outstanding balance of the Company's previous long-term debt as discussed in Note 8. Debt. If the Company is not able to generate cash proceeds from revenue sufficient to satisfy its cash obligations, the Company will need to finance future cash needs primarily through public or private equity offerings, debt financings, borrowings or strategic collaborations or licensing arrangements. If the Company is not able to secure additional funding when needed, on acceptable terms, it may have to delay, reduce the scope of or eliminate one or more research and development programs or selling and marketing initiatives which may have a material adverse effect on the Company's business, results of operations, financial condition and/or its ability to fund its scheduled obligations on a timely basis or at all. Concentrations of Credit Risk and Other Risks and Uncertainties The worldwide spread of coronavirus, or COVID-19, has created significant uncertainty in the global economy. There have been no comparable recent events that provide guidance as to the effect the spread of COVID-19 as a global pandemic may have, and, as a result, the ultimate impact of COVID-19 and the extent to which COVID-19 impacts the Company’s business, results of operations and financial condition will depend on future developments, which are highly uncertain and difficult to predict. If the financial markets or the overall economy are impacted for an extended period, the Company’s liquidity, revenues, supplies, goodwill and intangibles may be adversely affected. The Company considers the effects of the COVID-19 pandemic in developing our estimates. The majority of the Company's cash and cash equivalents are deposited with one major financial institution in the United States. Deposits in this institution may exceed the amount of insurance provided on such deposits. The Company has not experienced any losses on its deposits of cash and cash equivalents. Several of the components of the Company's sample collection kit and test reagents, and its nCounter Analysis Systems and related test kits are obtained from single-source suppliers. If these single-source suppliers fail to satisfy the Company's requirements on a timely basis, it could suffer delays in being able to deliver its diagnostic solutions, a possible loss of revenue, or incur higher costs, any of which could adversely affect its operating results. The Company is also subject to credit risk from its accounts receivable related to its sales. Credit risk for accounts receivable from testing revenue is incorporated in testing revenue accrual rates as the Company assesses historical collection rates and current developments to determine accrual rates and amounts the Company will ultimately collect. The Company generally does not perform evaluations of customers’ financial condition for testing revenue and generally does not require collateral. The Company assesses credit risk and the amount of accounts receivable the Company will ultimately collect for product, biopharmaceutical and collaboration revenue based on collection history, current developments and credit worthiness of the customer. The estimate of credit losses is not material at December 31, 2020. Through December 31, 2020, most of the Company's revenue have been derived from the sale of Afirma. To date, Afirma has been delivered primarily to physicians in the United States. The Company's third-party payers and other customers in excess of 10% of revenue and their related revenue as a percentage of total revenue were as follows: Year Ended December 31, 2020 2019 2018 Medicare 24 % 26 % 29 % UnitedHealthcare 11 % 11 % 12 % 35 % 37 % 41 % The Company's significant third-party payers and other customers in excess of 10% of total accounts receivable and their related accounts receivable balance as a percentage of total accounts receivable were as follows: As of December 31, 2020 2019 Medicare 13 % 15 % UnitedHealthcare 12 % 9 % Johnson and Johnson Services, Inc. * 10 % * less than 10% Cash Equivalents Cash equivalents consist of short-term, highly liquid investments with original maturities of three months or less from the date of purchase. Cash equivalents consist of amounts invested in a money market account primarily consisting of U.S. Treasury reserves, and overnight reverse repurchase agreements which are tri-party repurchase agreements and are collateralized by U.S. Treasury and agency securities of at least 102% of the principal amount. In a tri-party repurchase agreement, a third-party custodian bank functions as an independent intermediary to facilitate transfer of cash and holding the collateral on behalf of the underlying investor for the term of the agreement thereby minimizing risk and exposure to both parties. These overnight reverse repurchase agreements are included within cash equivalents due to their high liquidity and relatively low risk. Restricted Cash The Company had deposits of $603,000 included in long-term assets as of December 31, 2020 and December 31, 2019, restricted from withdrawal and held by a bank in the form of collateral for an irrevocable standby letter of credit held as security for the lease of the Company's South San Francisco facility. Acquisitions The Company first determines whether a set of assets acquired and liabilities assumed constitute a business and should be accounted for as a business combination. If the assets acquired are not a business, the Company accounts for the transaction as an asset acquisition. Business combinations are accounted for by using the acquisition method of accounting. Under the acquisition method, assets acquired, and liabilities assumed are recorded at their respective fair values as of the acquisition date in our consolidated financial statements. The excess of the fair value of consideration transferred over the fair value of the net assets acquired is recorded as goodwill. Contingent consideration obligations incurred in connection with a business combination are recorded at fair value on the acquisition date and remeasured at each subsequent reporting period until the related contingencies are resolved, with the resulting changes in fair value recorded in earnings. Accounts Receivable and Allowance for Doubtful Accounts for Product Sales Accounts receivable are stated at the amount management expects to collect from customers based on their outstanding invoices. Management reviews accounts receivable regularly to determine if any receivable will potentially be uncollectible and to estimate the amount of allowance for doubtful accounts necessary to reduce accounts receivable to its estimated net realizable value by analyzing the status of significant past due receivables. Product sales commenced in December 2019 and there was no allowance for doubtful accounts at either December 31, 2020 or 2019. Equity Investment In July 2020, the Company invested $1.0 million in the preferred stock of MAVIDx, Inc., or MAVIDx, a company developing a diagnostic platform for infectious diseases testing. MAVIDx is a variable interest entity, or VIE, and the Company's investment is a variable interest. The Company has determined that it is not the primary beneficiary of the VIE due to the fact that the Company does not have the power to direct the activities that impact the economic performance of MAVIDx or the obligation to fund its operations with ongoing financial support or contributions. MAVIDx is a private company and its equity securities are not traded or quoted in any securities exchange or in the over-the-counter market, and therefore does not have a readily determinable fair value. As such, the Company has elected to measure its investment in the preferred stock at cost, less any impairment, plus or minus changes resulting from observable price changes in orderly transactions for an identical or similar equity financings of MAVIDx, in accordance with Accounting Standards Codification, or ASC 321, Investments—Equity Securities . Based on the recent fourth quarter operating performance of MAVIDx and the volatile nature of the market in which it operates, the Company determined that the investment in MAVIDx is fully impaired as of December 31, 2020. As a result, an impairment loss of $1.0 million was recorded in the fourth quarter of 2020 and is included in general and administrative expense in the consolidated statements of operations and comprehensive loss. Property and Equipment Property and equipment are stated at cost less accumulated depreciation and amortization. Depreciation is computed using the straight-line method over the estimated useful lives of the assets, generally between three Finite-lived Intangible Assets Finite-lived intangible assets consist of intangible assets acquired as part of business combinations. The Company amortizes finite-lived intangible assets using the straight-line method over their estimated useful lives of 5 to 15 years, based on management's estimate of the period over which their economic benefits will be realized, product life and patent life. The Company tests these finite-lived intangible assets for impairment when events or circumstances indicate a reduction in the fair value below their carrying amounts. There was no impairment for the years ended December 31, 2020, 2019 or 2018. Goodwill Goodwill, derived from the Company's acquisition of Allegro Diagnostics Corp. in September 2014 and the exclusive global diagnostics license to the NanoString nCounter Analysis System and Prosigna and LymphMark assays in December 2019, is reviewed for impairment on an annual basis or more frequently if events or circumstances indicate that it may be impaired. The Company's goodwill evaluation is done annually on October 31 and is based on both qualitative and quantitative assessments regarding the fair value of goodwill relative to its carrying value. The Company has determined that it operates in a single segment and has a single reporting unit associated with the development and commercialization of diagnostic products. In the event the Company determines that it is more likely than not the carrying value of the reporting unit is higher than its fair value, quantitative testing is performed comparing recorded values to estimated fair values. If impairment is present, the impairment loss is measured as the excess of the recorded goodwill over its implied fair value. There was no impairment for the years ended December 31, 2020, 2019 or 2018. Fair Value of Financial Instruments The carrying amounts of certain financial instruments including cash and cash equivalents, accounts receivable, prepaid expenses and other current assets, accounts payable and accrued liabilities approximate fair value due to their relatively short maturities. See Note 6. Fair Value Measurements for further information on the fair value of the Company’s financial instruments. Revenue Recognition Testing Revenue The Company recognizes testing revenue in accordance with the provisions of ASC 606, Revenue from Contracts with Customers , or ASC 606. Most of the Company’s revenue is generated from the provision of testing services. These services are completed upon the delivery of test results to the prescribing physician, at which time the Company bills for the services. The Company recognizes revenue related to billings based on estimates of the amount that will ultimately be realized. In determining the amount to accrue for a delivered test, the Company considers factors such as payment history, payer coverage, whether there is a reimbursement contract between the payer and the Company, payment as a percentage of agreed upon rate (if applicable), amount paid per test and any current developments or changes that could impact reimbursement. These estimates require significant judgment by management. During 2020, the Company changed its testing revenue estimates due to actual and anticipated cash collections for tests delivered in 2019 or prior years and recognized additional revenue of $1.5 million, which resulted in a decrease in the Company's loss from operations of $1.5 million and a decrease in loss per share of $0.02 for the year ended December 31, 2020. During 2019, the Company changed its testing revenue estimates due to actual and anticipated cash collections for tests delivered in 2018 or prior years and recognized additional revenue of $1.6 million, which resulted in a decrease in the Company's loss from operations of $1.6 million and a decrease in loss per share of $0.04 for the year ended December 31, 2019. During 2018, the Company changed its testing revenue estimates due to actual and anticipated cash collections for tests delivered in 2017 or prior years and recognized additional revenue of $1.4 million, which resulted in a decrease in the Company's loss from operations of $1.4 million and a decrease in loss per share of $0.04 for the year ended December 31, 2018. Product Revenue The Company began recognizing product revenue in December 2019, when the Company executed an agreement with NanoString for the exclusive global license to the nCounter Analysis System for diagnostic use. More details on this agreement are in Note 4. Business Combination. Product revenue from instruments and diagnostic kits is recognized generally upon shipment or when the instrument is ready for use by the end customer, which is when title of the product has been transferred to the customer. This process involves identifying the contract with a customer, determining the performance obligations in the contract, determining the contract price, allocating the contract price to the distinct performance obligations in the contract, and recognizing revenue when the performance obligations have been satisfied. A performance obligation is considered distinct from other obligations in a contract when it provides a benefit to the customer either on its own or together with other resources that are readily available to the customer and is separately identified in the contract. Performance obligations are considered satisfied once the Company has transferred control of a product to the customer, meaning the customer has the ability to use and obtain the benefit of the product. The Company recognizes product revenue for satisfied performance obligations only when there are no uncertainties regarding payment terms or transfer of control. Shipping and handling costs incurred for product shipments are charged to the Company's customers and included in product revenue. Revenues are presented net of the taxes that are collected from customers and remitted to governmental authorities. There was no revenue from instrument sales for the years ended December 31, 2020, 2019 or 2018. Biopharmaceutical and Collaboration Revenue From time to time, the Company enters into arrangements for research and development and/or commercialization services. Such arrangements may require the Company to deliver various rights, services and/or samples, including intellectual property rights/licenses, R&D services, and/or commercialization services. The underlying terms of these arrangements generally provide for consideration to the Company in the form of nonrefundable upfront license fees, development and commercial performance milestone payments, royalty payments, and/or profit sharing. Net sales of data or other services to customers are recognized in accordance with ASC 606 and are classified under biopharmaceutical revenue. Certain milestone payments fall under the scope of ASC Topic 808, Collaborative Arrangements , or ASC 808, and are classified under collaboration revenue. Payments received that are not sales or services to a customer or collaboration revenue are recorded as offsets against research and development expense in the Company's consolidated statements of operations and comprehensive loss. In arrangements involving more than one performance obligation, each required performance obligation is evaluated to determine whether it qualifies as a distinct performance obligation based on whether (i) the customer can benefit from the good or service either on its own or together with other resources that are readily available and (ii) the good or service is separately identifiable from other promises in the contract. The consideration under the arrangement is then allocated to each separate distinct performance obligation based on its respective relative stand-alone selling price. The estimated selling price of each deliverable reflects the Company's best estimate of what the selling price would be if the deliverable was regularly sold by the Company on a stand-alone basis or using an adjusted market assessment approach if selling price on a stand-alone basis is not available. The consideration allocated to each distinct performance obligation is recognized as revenue when control of the related goods is transferred or services are performed. Consideration associated with at-risk substantive performance milestones is recognized as revenue when it is probable that a significant reversal of the cumulative revenue recognized will not occur. Should there be royalties, the Company utilizes the sales and usage-based royalty exception in arrangements that resulted from the license of intellectual property, recognizing revenues generated from royalties or profit sharing as the underlying sales occur. As part of the accounting for these arrangements, the Company must develop estimates and assumptions that require judgment to determine the underlying stand-alone selling price for each performance obligation which determines how the transaction price is allocated among the performance obligations. Generally, the estimation of the stand-alone selling price may include such estimates as independent evidence of market price, forecasted revenues or costs, development timelines, discount rates, and probabilities of technical and regulatory success. The Company evaluates each performance obligation to determine if they can be satisfied at a point in time or over time, and it measures the services delivered to the collaborative partner which are periodically reviewed based on the progress of the related program. The effect of any change made to an estimated input component and, therefore revenue or expense recognized, would be recorded as a change in estimate. In addition, variable consideration must be evaluated to determine if it is constrained and, therefore, excluded from the transaction price. Up-front Fees: If a license to the Company’s intellectual property is determined to be distinct from the other performance obligations identified in the arrangement, the Company recognizes revenues from the transaction price allocated to the license when the license is transferred to the licensee and the licensee is able to use and benefit from the license. For licenses that are bundled with other promises, the Company utilizes judgment to assess the nature of the combined performance obligation to determine whether the combined performance obligation is satisfied over time or at a point in time. Milestone Payments: At the inception of each arrangement that includes milestone payments (variable consideration), the Company evaluates whether the milestones are considered probable of being reached and estimates the amount to be included in the transaction price using the most likely amount method. If it is probable that a significant revenue reversal would not occur, the associated milestone value is included in the transaction price. Milestone payments that are not within the Company’s or the collaborative partner’s control, such as non-operational developmental and regulatory approvals, are generally not considered probable of being achieved until those approvals are received. At the end of each reporting period, the Company re-evaluates the probability of achievement of milestones that are within its or the collaborative partner’s control, such as operational developmental milestones and any related constraint, and if necessary, adjusts its estimate of the overall transaction price. Any such adjustments are recorded on a cumulative catch-up basis, which would affect collaboration revenues and earnings in the period of adjustment. Revisions to the Company’s estimate of the transaction price may also result in negative collaboration revenues and earnings in the period of adjustment. Diagnostic Development Agreements with Johnson & Johnson The Company has entered into contracts with the Lung Cancer Initiative at Johnson & Johnson to cooperate on the development of clinical data, to provide data generated by the Company and to license the right to use data under the Company's intellectual property rights. Under the terms of the agreements, the Company will provide data in exchange for up to $18.0 million in payments from Johnson & Johnson. The Company is also entitled to additional payments of up to $13.0 million, conditioned upon the achievement of certain milestones. The agreements are considered to be within the scope of ASC 808 with respect to the milestone payments, as the parties are active participants and exposed to the risks and rewards of the collaborative activity. The delivery of data under the collaborative arrangement, which the Company believes is a distinct service for which Johnson & Johnson meets the definition of a customer is within the scope of ASC 606. Using the concepts of ASC 606, the Company has identified the delivery of data as its only performance obligation. The grant of the license is not distinct from other performance obligations as the customer receives benefit only when other performance obligations are met. The Company further determined that the transaction prices under the arrangements are the $18.0 million in payments which was allocated to the obligation to deliver data. The $13.0 million in future potential payments is considered variable consideration because the Company determined that the potential payments are contingent upon regulatory and commercialization milestones that are uncertain to occur and, as such, were not included in the transaction price, and will be recognized accordingly as each potential payment becomes probable. The Company recognized revenue of $1.5 million and $7.0 million for the years ended December 31, 2020 and 2019, respectively, for the provision of data classified under biopharmaceutical revenue. The Company recognized revenue of zero and $4.0 million for the years ended December 31, 2020 and 2019, respectively, for the fulfillment of obligations relating to development milestones classified under collaboration revenue in the consolidated statement of operations and comprehensive loss. Accounts receivable from these contracts was zero and $2.0 million at December 31, 2020 and 2019, respectively. A payment of $950,000 received by the Company was classified as deferred revenue in the consolidated balance sheet at December 31, 2020. There was no deferred revenue related to these agreements at December 31, 2019. Other Collaboration and Service Agreements The Company has entered into agreements with biopharmaceutical companies and other diagnostic companies to provide them with data, development services and the right to develop tests on the nCounter Analysis System. For the year ended December 31, 2020 the Company recognized biopharmaceutical revenue of $1.0 million for the sale of commercial and development rights and $2.8 million for development services. For the year ended December 31, 2019 the Company recognized biopharmaceutical revenue of $1.0 million for development services and $0.1 million for the delivery of data. For the year ended December 31, 2018 the Company recognized biopharmaceutical revenue of $0.5 million for development services and $0.5 million for the delivery of data. Accounts receivable from these contracts was $0.4 million and zero at December 31, 2020 and 2019, respectively. As of December 31, 2020, the Company had received a payment of $0.3 million related to these contracts which is included in deferred revenue. Cost of Testing Revenue The components of the Company's cost of testing services are laboratory expenses, sample collection expenses, compensation expense, license fees and royalties, depreciation and amortization, other expenses such as equipment and laboratory supplies, and allocations of facility and information technology expenses. Costs associated with performing tests are expensed as the test is processed regardless of whether and when revenue is recognized with respect to that test. Cost of testing revenue for the year ended December 31, 2020 included a $1.1 million write-down of supplies for the expiration of reagents due to an anticipated decline in volumes resulting from the COVID-19 pandemic. Cost of Product Revenue Cost of product revenue consists primarily of costs of purchasing instruments and diagnostic kits from third-party contract manufacturers, installation, service and packaging and delivery costs. In addition, cost of product includes royalty costs for licensed technologies included in the Company’s products and labor expenses. Cost of product revenue for instruments and diagnostic kits is recognized in the period the related revenue is recognized. Shipping and handling costs incurred for product shipments are included in cost of product in the consolidated statements of operations and comprehensive loss. Cost of Biopharmaceutical Revenue Cost of biopharmaceutical revenue consists of costs of performing activities under arrangements that require the Company to perform research and development services on behalf of a customer pursuant to a biopharmaceutical service agreement. Research and Development Research and development expenses include expenses incurred to develop the Company's technology, collect clinical samples and conduct clinical studies to develop and support its products. These expenses consist of compensation expenses, direct research and development expenses such as prototype materials, laboratory supplies and costs associated with setting up and conducting clinical studies at domestic and international sites, professional fees, depreciation and amortization, other miscellaneous expenses and allocation of facility and information technology expenses. The Company expenses all research and development costs in the periods in which they are incurred. Income Taxes The Company accounts for income taxes under the liability method. Under this method, deferred tax assets and liabilities are determined based on the difference between the financial statement and tax bases of assets and liabilities using enacted tax rates in effect for the year in which the differences are expected to affect taxable income. Valuation allowances are established when necessary to reduce deferred tax assets to the amounts expected to be realized. The Company assesses all material positions taken in any income tax return, including all significant uncertain positions, in all tax years that are still subject to assessment or challenge by relevant taxing authorities. The Company's assessment of an uncertain tax position begins with the initial determination of the position's sustainability and is measured at the largest amount of benefit that is more-likely-than-not of being realized upon ultimate settlement. As of each balance sheet date, unresolved uncertain tax positions must be reassessed, and the Company will determine whether (i) the factors underlying the sustainability assertion have changed and (ii) the amount of the recognized tax benefit is still appropriate. The rec

Net Loss Per Share

Net Loss Per Share	12 Months Ended
Net Loss Per Share	Dec. 31, 2020
Earnings Per Share [Abstract]
Net Loss Per Share	Net Loss Per Share The following outstanding common stock equivalents have been excluded from diluted net loss per common share for the years ended December 31, 2020, 2019 and 2018 because their inclusion would be anti-dilutive: Year Ended December 31, 2020 2019 2018 Shares of common stock subject to outstanding options 4,564,777 5,394,944 5,998,163 Employee stock purchase plan 21,006 26,124 34,869 Restricted stock units 913,562 712,122 384,691 Total common stock equivalents 5,499,345 6,133,190 6,417,723

Business Combination

Business Combination	12 Months Ended
Business Combination	Dec. 31, 2020
Business Combinations [Abstract]
Business Combination	Business Combination Exclusive License to NanoString Diagnostics Platform On December 3, 2019, the Company executed an agreement with NanoString for the exclusive global diagnostics license to the nCounter Analysis System, the Prosigna breast cancer prognostic gene signature assay, and the LymphMark lymphoma subtyping assay. The strategic transaction positions the Company to expand its genomic diagnostics business globally, with the ability to deliver its advanced genomic tests to physicians and their patients via hospital and clinical laboratories throughout the European Union and other parts of the world. The Company has accounted for this agreement under ASC 805, Business Combinations . Pursuant to the terms of the agreement, Veracyte paid NanoString $40.0 million in cash and $10.0 million in Veracyte common stock, and may pay up to an additional $10.0 million in cash, contingent upon the commercial launch of Veracyte diagnostic tests for use on the platform. This contingency was valued at $6.1 million as of the acquisition date, recorded as a liability, and will be remeasured to fair value at each reporting date until the contingent consideration is settled. As of December 31, 2020, this contingency was remeasured to $7.6 million with the corresponding change included in general and administrative expense in the Company's consolidated statements of operations and comprehensive loss. Assets acquired are recorded based on valuations derived from estimated fair value assessments and assumptions used by the Company. While the Company believes that its estimates and assumptions underlying the valuations are reasonable, different estimates and assumptions could result in different valuations assigned to the individual assets acquired and the resulting amount of goodwill. The following table summarizes the fair values of assets acquired and liabilities assumed at the date of acquisition (in thousands of dollars): Prosigna product technology $ 4,120 Prosigna customer relationships 2,430 nCounter Dx license 46,880 LymphMark product technology 990 Total identifiable intangible assets acquired 54,420 Goodwill 1,668 Net assets acquired $ 56,088 Identifiable acquisition-related intangibles included in the above table are finite-lived and are being amortized on a straight-line basis over their estimated lives, which approximates the pattern in which the economic benefits of the intangible assets are expected to be realized, as follows: Estimated Useful life (In Years) Prosigna product technology 15 Prosigna customer relationships 5 nCounter Dx license 15 LymphMark product technology 7 Goodwill represents the excess of the purchase price over the fair value of the net tangible and intangible assets acquired. This acquisition includes $1.7 million of goodwill which the Company believes consists principally of the organized workforce that will help the Company execute its strategic plans in relation to the assets acquired. In accordance with ASC 350, Intangibles—Goodwill and Other , goodwill will not be amortized but will be tested for impairment at least annually. As of December 31, 2020, goodwill is not deductible for tax purposes, however, if contingent consideration is paid at a future date, the portions of contingent consideration paid and allocated to the intangible assets for tax purposes will be tax deductible. The unaudited pro forma financial information in the table below summarizes the combined revenue for the Company and acquired business from NanoString as though the acquisition had been executed as of January 1, 2018. The pro forma amounts have been adjusted in the table below. NanoString’s historical books and records did not contain the operating expense information to prepare the financial disclosures required in the pro forma table below. Thus, the pro forma financial disclosures are limited to revenue only. The unaudited pro forma revenue information is for informational purposes only and is not necessarily indicative of the revenue that would have been achieved if the acquisition had taken place as of January 1, 2018 (in thousands of dollars): Year Ended December 31, 2019 2018 Product revenue $ 11,040 $ 11,482

Balance Sheet Components

Balance Sheet Components	12 Months Ended
Balance Sheet Components	Dec. 31, 2020
Balance Sheet Related Disclosures [Abstract]
Balance Sheet Components	Balance Sheet Components Property and Equipment, Net Property and equipment consisted of the following (in thousands of dollars): December 31, 2020 2019 Leasehold improvements $ 6,863 $ 5,926 Laboratory equipment 10,643 9,655 Computer equipment 1,783 1,709 Software, including software developed for internal use 3,793 3,226 Furniture and fixtures 1,544 1,482 Construction-in-process 761 1,015 Total property and equipment, at cost 25,387 23,013 Accumulated depreciation and amortization (16,397) (14,080) Total property and equipment, net $ 8,990 $ 8,933 Depreciation and amortization expense was $2.8 million, $2.7 million and $2.9 million for the years ended December 31, 2020, 2019 and 2018, respectively. The Company had a capital lease for laboratory equipment that went into service in 2017. The lease was paid off in 2019 and the cost of $1.2 million was included in Property and Equipment as of December 31, 2019. The laboratory equipment had accumulated depreciation of $600,000 and $367,000 at December 31, 2019 and 2018, respectively and depreciation of $233,000 and $232,000 for the years ended December 31, 2019 and 2018, respectively. Finite-lived Intangible Assets, Net Finite-live intangible assets consisted of the following (in thousands of dollars): December 31, 2020 December 31, 2019 Weighted Average Amortization Period (Years) Gross Carrying Amount Accumulated Amortization Net Carrying Amount Gross Carrying Amount Accumulated Amortization Net Carrying Amount Percepta product technology $ 16,000 $ (6,133) $ 9,867 $ 16,000 $ (5,067) $ 10,933 15 Prosigna product technology 4,120 (298) 3,822 4,120 (17) 4,103 15 Prosigna customer relationships 2,430 (526) 1,904 2,430 (42) 2,388 5 nCounter Dx license 46,880 (3,386) 43,494 46,880 (263) 46,617 15 LymphMark product technology 990 (153) 837 990 (12) 978 7 Total $ 70,420 $ (10,496) $ 59,924 $ 70,420 $ (5,401) $ 65,019 14.6 Amortization of the Percepta product technology, which was acquired from the acquisition of Allegro in September 2014, began in April 2015 when research and development activities were deemed to be completed and is recognized on a straight-line basis. Amortization of the Prosigna product technology, Prosigna customer relationships, nCounter Dx license and LymphMark product technology, which were acquired under an agreement with NanoString, see Note 4. Business Combination, began in December 2019 and is recognized on a straight-line basis. Amortization of $5.1 million, $1.4 million and $1.1 million was recognized for the years ended December 31, 2020, 2019, and 2018, respectively. The estimated future aggregate amortization expense as of December 31, 2020 is as follows (in thousands of dollars): Year Ending December 31, Amounts 2021 $ 5,094 2022 5,094 2023 5,094 2024 5,054 2025 4,608 Thereafter 34,980 Total $ 59,924 Accrued Liabilities Accrued liabilities consisted of the following (in thousands of dollars): December 31, 2020 2019 Accrued compensation expense $ 9,201 $ 10,100 Accrued other 2,504 3,634 Total accrued liabilities $ 11,705 $ 13,734

Fair Value Measurements

Fair Value Measurements	12 Months Ended
Fair Value Measurements	Dec. 31, 2020
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements The Company records its financial assets and liabilities at fair value. The carrying amounts of certain financial instruments of the Company, including cash and cash equivalents, prepaid expenses and other current assets, accounts payable and accrued liabilities, approximate fair value due to their relatively short maturities. The carrying value of the Company's debt approximates its fair value because the interest rate approximates market rates that the Company could obtain for debt with similar terms. The fair value of the Company’s debt is estimated using the net present value of the payments, discounted at an interest rate that is consistent with market interest rates, which is a Level II input. The accounting guidance for fair value provides a framework for measuring fair value, clarifies the definition of fair value, and expands disclosures regarding fair value measurements. Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability (an exit price) in an orderly transaction between market participants at the reporting date. The accounting guidance establishes a three-tiered hierarchy, which prioritizes the inputs used in the valuation methodologies in measuring fair value as follows: • Level I: Inputs which include quoted prices in active markets for identical assets and liabilities; • Level II: Inputs other than Level I that are observable, either directly or indirectly, such as quoted prices for similar assets or liabilities; quoted prices in markets that are not active; or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities; and • Level III: Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities. The fair value of the Company's financial assets includes money market funds, overnight reverse repurchase agreements and a deposit for the lease of the Company's South San Francisco facility. Money market funds, included in cash and cash equivalents in the accompanying consolidated balance sheets, was $346.8 million and $57.6 million as of December 31, 2020 and 2019, respectively, and are Level I assets as described above. Overnight reverse repurchase agreements, included in cash and cash equivalents in the accompanying consolidated balance sheets, were zero and $100.0 million as of December 31, 2020 and 2019, respectively, and are Level II assets as described above. There were no unrealized gains or losses from overnight reverse repurchase agreements at December 31, 2020 and 2019. The deposit for the lease, included in restricted cash in the accompanying consolidated balance sheets, was $603,000 as of December 31, 2020 and 2019, and is a Level I asset as described above. There were no transfers between Levels 1, 2 or 3 for the years ended December 31, 2020, 2019, and 2018. The fair value of the contingent consideration in Note 4. Business Combination, associated with the agreement with NanoString on December 3, 2019, includes inputs that are not observable in the market and thus represents a Level III financial liability. The estimation of the fair value of the contingent consideration is based on the present value of the expected payments calculated by assessing the likelihood of when the related milestones would be achieved, discounted using the Company's estimated borrowing rate. These estimates form the basis for making judgments about the carrying value of the contingent consideration that are not readily apparent from other sources. Changes to the forecasts for the achievement of the milestones and the estimates of the borrowing rate can significantly affect the estimated fair value of the contingent consideration. As of December 31, 2020, the achievement of the milestones is not forecasted to occur within the next 12 months. As a result, the contingent consideration is included in long term liabilities in the consolidated balance sheets. As of December 31, 2020, the Company calculated the estimated fair value of the milestones using the following significant unobservable inputs: Value or Range Unobservable input (Weighted-Average) Discount rate 6.9% Probability of achievement 70% - 100% (86%)

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
Commitments and Contingencies	Dec. 31, 2020
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Operating Leases The Company leases its headquarters and laboratory facilities in South San Francisco, California under a non-cancelable lease agreement for approximately 59,000 square feet. The lease began in June 2015 and ends in March 2026 and contains extension of lease term and expansion options. In February 2017, the Company relinquished certain expansion rights for a nominal fee. The Company had deposits of $603,000 included in long-term assets as of December 31, 2020 and 2019, restricted from withdrawal and held by a bank in the form of collateral for an irrevocable standby letter of credit held as security for the lease of the South San Francisco facility. The Company also leases laboratory and office space in Austin, Texas under a lease that expires in January 2029 and includes options for expansion and early termination in 2025. The Company provided a cash security deposit for this lease of $139,000, included in other assets in the Company's balance sheets as of December 31, 2020 and 2019. The Company determined its operating lease liabilities for the two operating leases mentioned above using payments through their current expiration dates and a discount rate of 7.53% based on the rate that the Company would have to pay to borrow, on a collateralized basis, an amount equal to the lease payments in a similar economic environment. Operating lease liabilities along with the associated right-of-use assets are disclosed in the accompanying consolidated balance sheets. After the adoption of ASC 842, Leases , the Company classified its deferred rent for tenant improvements with its operating lease right-of-use assets on the consolidated balance sheets. Future minimum lease payments under non-cancelable operating leases as of December 31, 2020 are as follows (in thousands of dollars): Year Ending December 31, Amounts 2021 $ 2,401 2022 2,472 2023 2,543 2024 2,614 2025 2,685 Thereafter 1,542 Total future minimum lease payments 14,257 Less: amount representing interest 2,751 Present value of future lease payments 11,506 Less: short-term lease liabilities 1,589 Long-term lease liabilities $ 9,917 The Company recognizes rent expense on a straight-line basis over the non-cancelable lease period. Rent expense was $1.9 million, $1.9 million, and $1.9 million for the years ended December 31, 2020, 2019 and 2018, respectively. Supplies Purchase Commitments The Company had non-cancelable purchase commitments with suppliers to purchase a minimum quantity of supplies for approximately $4.8 million at December 31, 2020. Contingencies

Debt

Debt	12 Months Ended
Debt	Dec. 31, 2020
Debt Disclosure [Abstract]
Debt	Debt Loan and Security Agreement On November 3, 2017, the Company entered into a loan and security agreement (the “Loan and Security Agreement”) with Silicon Valley Bank. The Loan and Security Agreement allows the Company to borrow up to $35.0 million, with a $25.0 million advance term loan (the “Term Loan Advance”) and a revolving line of credit of up to $10.0 million (the “Revolving Line of Credit”). The Term Loan Advance was advanced upon the closing of the Loan and Security Agreement and was used to pay the outstanding balance of the Company’s existing long-term debt, which was canceled at that date. The Company had not drawn on the Revolving Line of Credit as of December 31, 2020. Borrowings under the Loan and Security Agreement mature on October 1, 2022. Amounts may be borrowed and repaid under the Revolving Line of Credit up until the earliest of full repayment or maturity of the Loan and Security Agreement, termination of the Loan and Security Agreement, or October 1, 2022. The Term Loan Advance bears interest at a variable rate equal to (i) the thirty-day U.S. London Interbank Offer Rate (“LIBOR”) plus (ii) 4.20%, with a minimum rate of 5.43% per annum. Principal amounts outstanding under the Revolving Line of Credit bear interest at a variable rate equal to (i) LIBOR plus (ii) 3.50%, with a minimum rate of 4.70% per annum. The average Term Loan Advance interest rate for the year ended December 31, 2020 was 5.4%. The Company may prepay the outstanding principal amount under the Term Loan Advance plus accrued and unpaid interest and, if the Term Loan Advance is repaid in full, a prepayment premium of $250,000. In January 2019, May 2019 and August 2020, the Company prepaid $12.5 million, $12.4 million and $0.1 million, respectively, of the principal amount of the Term Loan Advance. These prepayments did not trigger any prepayment premium because they were partial, not full, repayments of the principal amount. In addition, a final payment on the Term Loan Advance in the amount of $1.2 million is due upon the earlier of the maturity date of the Term Loan Advance or its payment in full. The Loan and Security Agreement contains customary representations, warranties, and events of default, as well as affirmative and negative covenants. As of December 31, 2020, the Company was in compliance with the loan covenants. The Company’s obligations under the Loan and Security Agreement are secured by substantially all of its assets (excluding intellectual property), subject to certain customary exceptions. As of December 31, 2020 and 2019, the net debt obligation for borrowings made under the Loan and Security Agreement was as follows (in thousands of dollars): December 31, 2020 2019 Debt principal $ — $ 100 End-of-term debt obligation 810 594 Net debt obligation $ 810 $ 694 As of December 31, 2020, the principal balance outstanding was one dollar. Future principal and end-of-term debt obligation payments due under the Loan and Security Agreement total $1.2 million and are due in 2022. As of December 31, 2020 and 2019, the accrued interest payable under the Loan and Security Agreement was immaterial. The end-of-term debt obligation accretes over the term of the Loan and Security Agreement until maturity and is included in interest expense in the Company's consolidated statements of operations and comprehensive loss. Interest Expense Interest expense was recognized as follows (in thousands of dollars): Year Ended December 31, 2020 2019 2018 Nominal debt interest $ 13 $ 332 $ 1,568 Amortization and write-off of debt discount and issuance costs — 107 57 End-of-term debt obligation interest 216 229 312 Interest on capital lease — 9 26 Total $ 229 $ 677 $ 1,963

Stockholders' Equity

Stockholders' Equity	12 Months Ended
Stockholders' Equity	Dec. 31, 2020
Equity [Abstract]
Stockholders' Equity	Stockholders' Equity Common Stock The Company's Restated Certificate of Incorporation authorizes the Company to issue 125,000,000 shares of common stock with a par value of $0.001 per share. The holder of each share of common stock shall have one vote for each share of stock. The common stockholders are also entitled to receive dividends whenever funds and assets are legally available and when declared by the Board of Directors, subject to the prior rights of holders of all series of convertible preferred stock outstanding. No dividends have been declared as of December 31, 2020. As of December 31, 2020 and 2019, the Company had reserved shares of common stock for issuance as follows: December 31, 2020 2019 Stock options and restricted stock units issued and outstanding 4,867,303 5,562,484 Stock options and restricted stock units available for grant under stock option plans 3,061,589 1,954,804 Common stock available for the Employee Stock Purchase Plan 1,571,395 173,168 Total 9,500,287 7,690,456 In August 2020, the Company issued and sold 6,900,000 shares of common stock in a registered public offering, including 900,000 shares issued and sold upon the underwriters' exercise in full of their option to purchase additional shares, at a price to the public of $30.00 per share. The Company's net proceeds from the offering were $193.8 million, after deducting underwriting commissions and offering expenses of $13.2 million. In May 2019, the Company issued and sold 6,325,000 shares of common stock in a registered public offering, including 825,000 shares issued and sold upon the underwriters’ exercise in full of their option to purchase additional shares, at a price to the public of $23.25 per share. The Company's net proceeds from the offering were approximately $137.8 million, after deducting underwriting discounts and commissions and offering expenses of $9.2 million. In July 2018, the Company issued and sold 5,750,000 shares of common stock in a registered public offering, including 750,000 shares issued and sold upon the underwriters' exercise in full of their option to purchase additional shares, at a price to the public of $10.25 per share. The Company's net proceeds from the offering were $55.0 million, after deducting underwriting commissions and offering expenses of $3.9 million.

Stock Incentive Plans

Stock Incentive Plans	12 Months Ended
Stock Incentive Plans	Dec. 31, 2020
Share-based Payment Arrangement [Abstract]
Stock Incentive Plans	Stock Incentive Plans Stock Plans In February 2008, the Company adopted the 2008 Stock Plan (the "2008 Plan"). The 2008 Plan provides for the granting of options to purchase common stock and common stock to employees, directors and consultants of the Company. The Company may grant incentive stock options, or ISOs, non-statutory stock options, or NSOs, or restricted stock under the 2008 Plan. ISOs may only be granted to Company employees (including directors who are also considered employees). NSOs and restricted stock may be granted to Company employees, directors and consultants. Options may be granted for terms of up to ten years from the date of grant, as determined by the Board of Directors, provided however, that with respect to an ISO granted to a person who owns stock representing more than 10% of the voting power of all classes of stock of the Company, the term shall be for no more than five years from the date of grant. The exercise price of options granted must be at a price no less than 100% of the estimated fair value of the shares on the date of grant, as determined by the Board of Directors, provided however, that with respect to an ISO granted to an employee who at the time of grant of such option owns stock representing more than 10% of the voting power of all classes of stock of the Company, the exercise price shall not be less than 110% of the estimated fair value of the shares on the date of grant. In October 2013, the Company adopted the 2013 Stock Incentive Plan (the "2013 Plan"). The 2013 Plan was subsequently approved by the Company's stockholders and became effective on November 4, 2013, immediately before the closing of the Company's initial public offering, or IPO. Following the effectiveness of the 2013 Plan, no additional options were granted under the 2008 Plan. An aggregate of 1,700,000 shares were initially reserved for issuance under the 2013 Plan. In addition, to the extent that any awards outstanding or subject to vesting restrictions under the 2008 Plan are subsequently forfeited or terminated for any reason before being exercised or settled, the shares of common stock reserved for issuance pursuant to such awards as of the closing of the IPO will become available for issuance under the 2013 Plan. The remaining shares available for grant under the 2008 Plan became available for issuance under the 2013 Plan upon the closing of the IPO. On the first day of each year from 2014 to 2023, the 2013 Plan authorizes an annual increase of the lesser of 4% of outstanding shares on the last day of the immediately preceding fiscal year or a lesser amount as determined by the Company's Board of Directors. As of December 31, 2020, 3,061,589 shares were available for future issuance under the 2013 Plan. Pursuant to the 2013 Plan, stock options, restricted shares, stock units, including restricted stock units and stock appreciation rights may be granted to employees, consultants, and outside directors of the Company. Options granted may be either ISOs or NSOs. Stock options are governed by stock option agreements between the Company and recipients of stock options. ISOs and NSOs may be granted under the 2013 Plan at an exercise price of not less than 100% of the fair market value of the common stock on the date of grant, determined by the Compensation Committee of the Board of Directors. Options become exercisable and expire as determined by the Compensation Committee, provided that the term of ISOs may not exceed ten years from the date of grant. Stock option agreements may provide for accelerated exercisability in the event of an optionee's death, disability, or retirement or other events. Stock units are governed by stock unit agreements between the Company and recipients of stock units. Stock units may be granted under the 2013 Plan and the number of stock units awarded are determined by the Compensation Committee of the Board of Directors. Stock units vest and expire as determined by the Compensation Committee. Stock unit agreements may provide for accelerated vesting in the event of a stock unit holder's death, disability, or retirement or other events. Any outside director who was not previously an employee and who first joins the Company's Board of Directors on or after the effective date of the 2013 Plan will be automatically granted an initial NSO to purchase 35,000 shares of common stock upon first becoming a member of the Board of Directors. The shares subject to the initial option will vest and become exercisable one-third (1/3) each of the first, second and third annual anniversaries of the date of grant. On the first business day after each regularly scheduled annual meeting of stockholders, each outside director who was not elected to the Board of Directors for the first time at such meeting and who will continue serving as a member of the Board of Directors thereafter will be automatically granted an option to purchase 10,000 shares of common stock, provided that the outside director has served on the Board of Directors for at least six months. Each annual option will vest and become exercisable on the first anniversary of the date of grant, or immediately prior to the next regular annual meeting of the Company's stockholders following the date of grant if the meeting occurs prior to the first anniversary date. The options granted to outside directors will have a per share exercise price equal to 100% of the fair market value of the underlying shares on the date of grant and will become fully vested in the event of a change of control. In addition, such options will terminate on the earlier of (i) the day before the 10th anniversary of the date of grant or (ii) the date 12 months after the termination of the outside director's service for any reason. The following table summarizes activity under the Company's stock incentive plans (aggregate intrinsic value in thousands): Shares Stock Options Weighted Weighted Average Aggregate Balance—December 31, 2019 1,954,804 5,562,484 $ 10.66 6.97 $ 79,760 Additional shares authorized 1,985,013 — Granted - stock options (983,900) 983,900 26.40 Granted - restricted stock units (451,709) 451,709 Canceled 421,558 (421,558) 6.51 Exercised — (1,345,134) 8.67 Restricted stock units vested — (364,098) Tax portion of restricted stock units vested 135,823 — Balance—December 31, 2020 3,061,589 4,867,303 $ 15.14 6.98 $ 135,879 Options vested and exercisable—December 31, 2020 2,316,166 $ 10.35 5.78 $ 89,376 Options vested and expected to vest—December 31, 2020 3,858,859 $ 14.78 6.91 $ 131,816 The aggregate intrinsic value was calculated as the difference between the exercise price of the options to purchase common stock and the fair market value of the Company's common stock, which was $48.94 and $27.92 per share as of December 31, 2020 and 2019, respectively. The weighted average fair value of options to purchase common stock granted was $12.97, $11.07 and $3.62 for the years ended December 31, 2020, 2019 and 2018, respectively. The aggregate estimated grant date fair value of employee options to purchase common stock vested during the years ended December 31, 2020, 2019 and 2018 was $7.3 million, $4.4 million and $4.1 million, respectively. The intrinsic value of stock options exercised was $32.9 million, $31.3 million and $4.9 million for the years ended December 31, 2020, 2019 and 2018, respectively. The weighted average fair value of restricted stock units granted was $27.09 and $21.90 for the years ended December 31, 2020, and 2019, respectively. The intrinsic value of restricted stock units vested was $10.3 million and $2.7 million for the years ended December 31, 2020 and 2019, respectively. Employee Stock Purchase Plan In May 2015, the Company's stockholders approved the Company's ESPP. The ESPP provides eligible employees with an opportunity to purchase common stock from the Company and to pay for their purchases through payroll deductions. The ESPP will be implemented through a series of offerings of purchase rights to eligible employees. Under the ESPP, the Compensation Committee of the Company's Board of Directors may specify offerings with a duration of not more than 12 months, and may specify shorter purchase periods within each offering. During each purchase period, payroll deductions will accumulate, without interest. On the last day of the purchase period, accumulated payroll deductions will be used to purchase common stock for employees participating in the offering. The purchase price will be specified pursuant to the offering, but cannot, under the terms of the ESPP, be less than 85% of the fair market value per share of the Company's common stock on either the offering date or on the purchase date, whichever is less. The Company's Board of Directors has determined that the purchase periods initially shall have a duration of six months, that the first purchase period began on August 3, 2015 and that the purchase price will be 85% of the fair market value per share of the Company's common stock on either the offering date or the purchase date, whichever is less. The length of the purchase period applicable to U.S. employees and the purchase price may not be changed without the approval of the independent members of the Compensation Committee of the Company's Board of Directors. The Compensation Committee has determined that if the fair market value of a share of the Company's common stock on any purchase date within a particular offering period is less than the fair market value on the start date of that offering period, then the offering period will automatically terminate and the employees in that offering period will automatically be transferred and enrolled in a new offering period which will begin on the next day following such purchase date. No employee is permitted to accrue, under the ESPP, a right to purchase stock of the Company having a value in excess of $25,000 of the fair market value of such stock (determined at the time the right is granted) for each calendar year. As of December 31, 2020, 1,571,395 shares of common stock were reserved for issuance under the ESPP. Stock-based Compensation The following table summarizes stock-based compensation expense related to stock options, restricted stock units and the ESPP for the years ended December 31, 2020, 2019 and 2018, and are included in the consolidated statements of operations and comprehensive loss as follows (in thousands of dollars): Year Ended December 31, 2020 2019 2018 Cost of testing revenue $ 369 $ 277 $ 130 Research and development 2,690 1,856 1,018 Selling and marketing 3,474 2,938 1,866 General and administrative 6,462 4,736 2,944 Total stock-based compensation expense $ 12,995 $ 9,807 $ 5,958 As of December 31, 2020, the Company had $25.7 million of unrecognized compensation expense related to unvested stock options and restricted stock units, which is expected to be recognized over an estimated weighted-average period of 2.40 years. The estimated grant-date fair value of stock options was calculated using the Black-Scholes option-pricing model, based on the following assumptions. • Expected Term : The expected term represents the period that the options granted are expected to be outstanding. During 2020 it was determined using the Company's historical data and during prior years it was determined using the simplified method (based on the mid-point between the vesting date and the end of the contractual term). • Expected Volatility : During 2020, the Company used the historical volatility of its common stock. For prior years, the Company used an average historical stock price volatility of comparable public companies as the Company did not have sufficient trading history for its common stock. • Risk-Free Interest Rate : The Company based the risk-free interest rate over the expected term of the options based on the constant maturity rate of U.S. Treasury securities with similar maturities as of the date of the grant. • Expected Dividend Yield : The Company has not paid and does not anticipate paying any dividends in the near future. Therefore, the expected dividend yield was zero. The estimated grant-date fair value of employee stock options using the Black-Scholes option-pricing model was based on the following assumptions: Year Ended December 31, 2020 2019 2018 Weighted-average volatility 54.40 - 58.20% 52.90 - 53.40% 50.40 - 52.70% Weighted-average expected term (years) 5.24 - 5.42 5.50 - 6.08 5.50 - 6.08 Risk-free interest rate 0.24 - 0.92% 1.90 - 2.60% 2.40 - 3.10% Expected dividend yield — — — The estimated fair value of non-employee stock options using the Black-Scholes option-pricing model was based on the following assumptions: Year Ended December 31, 2020 2019 2018 Weighted-average volatility —% —% 43.60 - 50.50% Weighted-average expected term (years) — — 0.25 - 6.75 Risk-free interest rate —% —% 1.84 - 2.87% Expected dividend yield — — — There were no non-employee stock options outstanding as of December 31, 2020 or December 31, 2019. The estimated grant date fair value of the ESPP shares was calculated using the Black-Scholes option-pricing model, based on the following assumptions: Year Ended December 31, 2020 2019 2018 Weighted-average volatility 54.16 - 85.01% 53.38 - 71.77% 42.88 - 47.74% Weighted-average expected term (years) 0.50 - 1.00 0.50 - 1.00 0.50 - 1.00 Risk-free interest rate 0.11 - 1.56% 1.88 - 2.56% 1.64 - 2.45% Expected dividend yield — — —

Thyroid Cytopathology Partners

Thyroid Cytopathology Partners	12 Months Ended
Thyroid Cytopathology Partners	Dec. 31, 2020
Thyroid Cytopathology Partners
Thyroid Cytopathology Partners	Thyroid Cytopathology PartnersThe Company has an agreement with a specialized pathology practice, Thyroid Cytopathology Partners, ("TCP"), to provide testing services to the Company (the "TCP Agreement"). The TCP Agreement is effective through October 31, 2022, and thereafter automatically renews every year unless either party provides notice of intent not to renew at least 12 months prior to the end of the then-current term. Under the TCP Agreement, the Company pays TCP based on a fixed price per test schedule which is reviewed periodically for changes in market pricing, and the TCP Agreement included a clause allowing TCP to sublease a portion of the Company's facility in Austin, Texas. The Company does not have an ownership interest in or provide any form of financial or other support to TCP. The Company previously concluded that TCP represented a variable interest entity as a result of the facility arrangement clause, but that the Company was not the primary beneficiary as it did not have the ability to direct the activities that most significantly impacted TCP's economic performance, and therefore did not consolidate TCP. On February 14, 2019, the TCP Agreement was amended to remove the facility clause. Accordingly, the Company believes TCP was no longer a variable interest entity as of that date.TCP's portion of rent and related operating expenses reimbursed to the Company for the shared space at the Austin, Texas facility was $11,000 and $128,000 for the years ended December 31, 2019 and 2018 and is included other income, net in the Company's consolidated statements of operations and comprehensive loss.

Income Taxes

Income Taxes	12 Months Ended
Income Taxes	Dec. 31, 2020
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes The Company generated a pretax loss of $34.8 million, $12.5 million and $23.0 million in the United States for the years ended December 31, 2020, 2019 and 2018, respectively. Since inception, the Company has not generated any pretax income or loss outside of the United States. The Company recorded no provision for income taxes during the years ended December 31, 2020, 2019 or 2018. The Company follows FASB ASC No. 740, Income Taxes for the Computation and Presentation of its Tax Provision. The following table presents a reconciliation of the income tax expense computed at the statutory federal rate and the Company's income tax expense for the periods presented (in thousands of dollars): Year Ended December, 31, 2020 2019 2018 U.S. federal taxes at statutory rate $ (7,302) $ (2,632) $ (4,825) State tax (net of federal benefit) (1,794) (828) — Foreign rate differential 1 — — Non deductible officers' compensation 1,443 439 409 Permanent differences 131 221 285 Stock based compensation including excess tax benefit (4,881) (4,366) (256) Tax credits (588) (996) (777) Change in valuation allowance 12,990 8,162 5,164 Total $ — $ — $ — Deferred income taxes reflect the net tax effects of temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes. Significant components of the Company's deferred tax assets and liabilities are as follows (in thousands of dollars): Year Ended December 31, 2020 2019 2018 Deferred tax assets: Net operating loss carryforwards $ 68,113 $ 56,506 $ 50,410 Research and development credits 6,167 5,579 4,584 Stock-based compensation 2,696 2,246 1,032 NanoString intangibles and goodwill 908 380 — Operating lease liability 2,826 3,068 — Accruals and other 2,623 2,610 2,918 Gross deferred tax assets 83,333 70,389 58,944 Valuation allowance (78,650) (65,228) (55,366) Net deferred tax assets 4,683 5,161 3,578 Deferred tax liabilities: Property and equipment (334) (471) (695) In-process research and development (2,423) (2,597) (2,883) ROU assets (1,926) (2,093) — Gross deferred tax liabilities (4,683) (5,161) (3,578) Net deferred tax liabilities (4,683) (5,161) (3,578) Net deferred taxes $ — $ — $ — The Company has established a full valuation allowance against its net deferred tax assets due to the uncertainty surrounding realization of such assets. The valuation allowance increased $13.4 million, $9.9 million and $3.7 million during the years ended December 31, 2020, 2019 and 2018, respectively. As of December 31, 2020, the Company had net operating loss carryforwards of approximately $282.9 million, $63.0 million and $72.2 million available to reduce future taxable income, if any, for federal, California and other state income tax purposes, respectively. The U.S. federal net operating loss carryforwards will begin to expire in 2026 while for state purposes, the net operating losses begin to expire in 2028. As of December 31, 2020, the Company had net research and development credit carryforwards of approximately $5.3 million and $5.2 million available to reduce future taxable income, if any, for federal and state income tax purposes, respectively. The federal credit carryforwards begin to expire in 2028. California credits have no expiration date. Other state credit carryforwards begin to expire in 2023. The Internal Revenue Code of 1986, as amended, imposes restrictions on the utilization of net operating losses and tax credits in the event of an "ownership change" of a corporation. Accordingly, a company's ability to use net operating losses and tax credits may be limited as prescribed under Internal Revenue Code Section 382 and 383 ("IRC Section 382"). Events which may cause limitations in the amount of the net operating losses or tax credits that the Company may use in any one year include, but are not limited to, a cumulative ownership change of more than 50% over a three-year period. Utilization of the federal and state net operating losses may be subject to substantial annual limitation due to the ownership change limitations provided by the IRC Section 382 rules and similar state provisions. In the event the Company has any changes in ownership, net operating losses and research and development credit carryovers could be limited and may expire unutilized. Uncertain Tax Positions As of December 31, 2020, the Company had unrecognized tax benefits of $3.6 million, none of which would currently affect the Company's effective tax rate if recognized due to the Company's deferred tax assets being fully offset by a valuation allowance. The Company does not anticipate that the amount of unrecognized tax benefits relating to tax positions existing at December 31, 2020 will significantly increase or decrease within the next 12 months. A reconciliation of the beginning and ending amount of unrecognized tax benefits is as follows (in thousands of dollars): Year Ended December 31, 2020 2019 2018 Unrecognized tax benefits, beginning of period $ 3,278 $ 2,799 $ 2,523 Gross increases—tax position in prior period — — — Gross decreases—tax position in prior period — — (97) Gross increases—current period tax position 285 479 373 Lapse of statute of limitations — — — Unrecognized tax benefits, end of period $ 3,563 $ 3,278 $ 2,799 It is the Company's policy to include penalties and interest expense related to income taxes as a component of other income (expense), net, and interest expense, respectively, as necessary. There was no interest expense or penalties related to unrecognized tax benefits recorded through December 31, 2020. The Company's major tax jurisdictions are the United States and California. All of the Company's tax years will remain open for examination by the Federal and state tax authorities for three On March 27, 2020, the Coronavirus Aid, Relief, and Economic Security Act (CARES Act) was enacted in response to the COVID-19 pandemic. The Company does not expect the provisions of the legislation to have a significant impact on the effective tax rate of the Company.

401(k) Plan

401(k) Plan	12 Months Ended
401(k) Plan	Dec. 31, 2020
Retirement Benefits [Abstract]
401(k) Plan	401(k) PlanThe Company sponsors a 401(k) defined contribution plan covering all employees. Under the plan, participants are entitled to make pre-tax contributions up to the annual maximums established by the Internal Revenue Service. The Company, at its discretion, may make matching contributions to the 401(k) plan. Employer contributions to the plan were $613,000, $509,000 and $448,000 for the years ended December 31, 2020, 2019, and 2018, respectively.

Selected Quarterly Financial Da

Selected Quarterly Financial Data (Unaudited)	12 Months Ended
Selected Quarterly Financial Data (Unaudited)	Dec. 31, 2020
Quarterly Financial Information Disclosure [Abstract]
Selected Quarterly Financial Data (Unaudited)	Selected Quarterly Financial Data (Unaudited)The following table presents selected unaudited financial data for each of the eight quarters in the two-year period ended December 31, 2020. The Company believes this information reflects all recurring adjustments necessary to fairly present this information when read in conjunction with the Company's consolidated financial statements and the related notes. Net loss per common share, basic and diluted, for the four quarters of each fiscal year may not sum to the total for the fiscal year because of rounding. The results of operations for any quarter are not necessarily indicative of the results to be expected for any future period (in thousands of dollars, except for share and per share data): Quarter Ended March 31 June 30 September 30 December 31 2020: Revenue $ 31,122 $ 20,704 $ 31,121 $ 34,536 Net loss (11,716) (11,025) (4,124) (8,044) Net loss per common share, basic and diluted (0.24) (0.22) (0.08) (0.14) Shares used to compute net loss per common share, basic and diluted 49,792,631 50,212,123 54,858,052 58,023,753 2019: Revenue $ 29,529 $ 30,136 $ 30,973 $ 29,730 Net loss (1,917) (2,494) (730) (7,458) Net loss per common share, basic and diluted (0.05) (0.05) (0.02) (0.15) Shares used to compute net loss per common share, basic and diluted 41,168,593 45,586,081 48,588,296 49,095,703

Subsequent Events

Subsequent Events	12 Months Ended
Subsequent Events	Dec. 31, 2020
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events Acquisition of Decipher On February 2, 2021, the Company, entered into an Agreement and Plan of Merger, or the Merger Agreement, with Delight Merger Sub I, Inc., a Delaware corporation and wholly owned subsidiary of Veracyte, or Delight Merger Sub I, Delight Merger Sub II, LLC, a Delaware limited liability company and wholly owned subsidiary of Veracyte, or Delight Merger Sub II, Decipher, and Fortis Advisors LLC, solely in its capacity as the stockholders’ agent. Decipher is a commercial-stage precision oncology company, with a focus in urologic oncology specific to prostate and bladder cancers. Pursuant to the terms of the Merger Agreement, Delight Merger Sub I will merge with and into Decipher and Decipher shall survive and become a wholly owned subsidiary of Veracyte, or the First Merger. Promptly following consummation of the First Merger, Decipher will merge with and into Delight Merger Sub II, with Merger Sub II surviving as a wholly owned subsidiary of Veracyte (together, the “Merger”). Under terms of the Merger Agreement, Decipher Biosciences will become a wholly owned subsidiary of Veracyte. At the effective time of the Merger, or the Closing, Veracyte will pay $600 million in cash to Decipher security holders, subject to customary purchase price adjustments for cash, unpaid indebtedness, unpaid transaction expenses and the aggregate exercise prices of all Decipher options. The Merger Agreement contains customary representations, warranties, covenants and agreements of Decipher and Veracyte. The Closing is subject to customary closing conditions, including approval by the Decipher stockholders and the expiration or termination of the applicable waiting period under the Hart-Scott-Rodino Antitrust Improvements Act of 1976, as amended. The Merger Agreement also provides customary termination rights to each of the parties. Public Offering of Common Stock On February 9, 2021, the Company issued and sold 8,547,297 shares of common stock in a registered public offering, including 1,114,864 shares issued and sold upon the underwriters' exercise in full of their option to purchase additional shares, at a price to the public of $74.00 per share. The Company's net proceeds from the offering were $593.8 million, after deducting underwriting commissions and offering expenses of $38.7 million.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	12 Months Ended
Summary of Significant Accounting Policies (Policies)	Dec. 31, 2020
Accounting Policies [Abstract]
Basis of Presentation	Basis of PresentationThe Company's consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States ("U.S. GAAP"). The consolidated financial statements include the accounts of the Company and its wholly-owned subsidiary, which was created in 2019 to process certain administrative functions associated with the business combination in Note 4. Business Combination. All intercompany accounts and transactions have been eliminated in consolidation.
Reclassifications	Reclassifications Certain prior period balances have been reclassified to conform to current period presentation of the Company’s consolidated financial statements and accompanying notes. Such reclassifications have no effect on previously reported results of operations, accumulated deficit, subtotals of operating, investing or financing cash flows or consolidated balance sheet totals; however, for the year ended December 31, 2019, the Company reclassified $1.0 million of changes in operating assets and liabilities to noncash lease expense in the statement of cash flows.
Use of Estimates	Use of Estimates The preparation of consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent liabilities as of the date of the consolidated financial statements and the reported amounts of revenue and expenses during the reporting period. Significant items subject to such estimates include: revenue recognition; write-down of supplies; the useful lives of property and equipment; the recoverability of long-lived assets; the incremental borrowing rate for leases; the estimation of the fair value of intangible assets and contingent consideration; variable interest entity assessment; impairment of equity investment, at cost; stock options; income tax uncertainties, including a valuation allowance for deferred tax assets; reserve on accounts receivable and contingencies. The Company bases these estimates on historical and anticipated results, trends, and various other assumptions that the Company believes are reasonable under the circumstances, including assumptions as to future events. These estimates form the basis for making judgments about the carrying values of assets and liabilities and recognized revenue and expenses that are not readily apparent from other sources. Actual results could differ from those estimates and assumptions.
Concentrations of Credit Risk and Other Risks and Uncertainties	Concentrations of Credit Risk and Other Risks and Uncertainties The worldwide spread of coronavirus, or COVID-19, has created significant uncertainty in the global economy. There have been no comparable recent events that provide guidance as to the effect the spread of COVID-19 as a global pandemic may have, and, as a result, the ultimate impact of COVID-19 and the extent to which COVID-19 impacts the Company’s business, results of operations and financial condition will depend on future developments, which are highly uncertain and difficult to predict. If the financial markets or the overall economy are impacted for an extended period, the Company’s liquidity, revenues, supplies, goodwill and intangibles may be adversely affected. The Company considers the effects of the COVID-19 pandemic in developing our estimates. The majority of the Company's cash and cash equivalents are deposited with one major financial institution in the United States. Deposits in this institution may exceed the amount of insurance provided on such deposits. The Company has not experienced any losses on its deposits of cash and cash equivalents. Several of the components of the Company's sample collection kit and test reagents, and its nCounter Analysis Systems and related test kits are obtained from single-source suppliers. If these single-source suppliers fail to satisfy the Company's requirements on a timely basis, it could suffer delays in being able to deliver its diagnostic solutions, a possible loss of revenue, or incur higher costs, any of which could adversely affect its operating results. The Company is also subject to credit risk from its accounts receivable related to its sales. Credit risk for accounts receivable from testing revenue is incorporated in testing revenue accrual rates as the Company assesses historical collection rates and current developments to determine accrual rates and amounts the Company will ultimately collect. The Company generally does not perform evaluations of customers’ financial condition for testing revenue and generally does not require
Cash Equivalents	Cash Equivalents Cash equivalents consist of short-term, highly liquid investments with original maturities of three months or less from the date of purchase. Cash equivalents consist of amounts invested in a money market account primarily consisting of U.S. Treasury reserves, and overnight reverse repurchase agreements which are tri-party repurchase agreements and are collateralized by U.S. Treasury and agency securities of at least 102% of the principal amount. In a tri-party repurchase agreement, a third-party custodian bank functions as an independent intermediary to facilitate transfer of cash and holding the collateral on behalf of the underlying investor for the term of the agreement thereby minimizing risk and exposure to both parties. These overnight reverse repurchase agreements are included within cash equivalents due to their high liquidity and relatively low risk.
Restricted Cash	Restricted Cash The Company had deposits of $603,000 included in long-term assets as of December 31, 2020 and December 31, 2019, restricted from withdrawal and held by a bank in the form of collateral for an irrevocable standby letter of credit held as security for the lease of the Company's South San Francisco facility.
Acquisitions	Acquisitions The Company first determines whether a set of assets acquired and liabilities assumed constitute a business and should be accounted for as a business combination. If the assets acquired are not a business, the Company accounts for the transaction as an asset acquisition. Business combinations are accounted for by using the acquisition method of accounting. Under the acquisition method, assets acquired, and liabilities assumed are recorded at their respective fair values as of the acquisition date in our consolidated financial statements. The excess of the fair value of consideration transferred over the fair value of the net assets acquired is recorded as goodwill. Contingent consideration obligations incurred in connection with a business
Accounts Receivable and Allowance for Doubtful Accounts for Product Sales	Accounts Receivable and Allowance for Doubtful Accounts for Product Sales Accounts receivable are stated at the amount management expects to collect from customers based on their outstanding invoices. Management reviews accounts receivable regularly to determine if any receivable will potentially be uncollectible and to estimate the amount of allowance for doubtful accounts necessary to reduce accounts receivable to its estimated net realizable value by analyzing the status of significant past due receivables.
Equity Investments	Equity Investment In July 2020, the Company invested $1.0 million in the preferred stock of MAVIDx, Inc., or MAVIDx, a company developing a diagnostic platform for infectious diseases testing. MAVIDx is a variable interest entity, or VIE, and the Company's investment is a variable interest. The Company has determined that it is not the primary beneficiary of the VIE due to the fact that the Company does not have the power to direct the activities that impact the economic performance of MAVIDx or the obligation to fund its operations with ongoing financial support or contributions. MAVIDx is a private company and its equity securities are not traded or quoted in any securities exchange or in the over-the-counter market, and therefore does not have a readily determinable fair value. As such, the Company has elected to measure its investment in the preferred stock at cost, less any impairment, plus or minus changes resulting from observable price changes in orderly transactions for an identical or similar equity financings of MAVIDx, in accordance with Accounting Standards Codification, or ASC 321, Investments—Equity Securities . Based on the recent fourth quarter operating performance of MAVIDx and the volatile nature of the market in which it operates, the Company determined that the investment in MAVIDx is fully impaired as of December 31, 2020. As a result, an impairment loss of $1.0 million was recorded in the fourth quarter of 2020 and is included in general and administrative expense in the consolidated statements of operations and comprehensive loss.
Property and Equipment	Property and Equipment Property and equipment are stated at cost less accumulated depreciation and amortization. Depreciation is computed using the straight-line method over the estimated useful lives of the assets, generally between three
Finite-lived Intangible Assets	Finite-lived Intangible Assets Finite-lived intangible assets consist of intangible assets acquired as part of business combinations. The Company amortizes finite-lived intangible assets using the straight-line method over their estimated useful lives of 5 to 15 years, based on management's estimate of the period over which their economic benefits will be realized, product life and patent life. The Company tests these finite-lived intangible assets for impairment when events or circumstances indicate a reduction in the fair value below their carrying amounts. There was no impairment for the years ended December 31, 2020, 2019 or 2018.
Goodwill	Goodwill Goodwill, derived from the Company's acquisition of Allegro Diagnostics Corp. in September 2014 and the exclusive global diagnostics license to the NanoString nCounter Analysis System and Prosigna and LymphMark assays in December 2019, is reviewed for impairment on an annual basis or more frequently if events or circumstances indicate that it may be impaired. The Company's goodwill evaluation is done annually on October 31 and is based on both qualitative and quantitative assessments regarding the fair value of goodwill relative to its carrying value. The Company has determined that it operates in a single segment and has a single reporting unit associated with the development and commercialization of diagnostic products. In the event the Company determines that it is more likely than not the carrying value of the reporting unit is higher than its fair value, quantitative testing is performed comparing recorded values to estimated fair values. If impairment is present, the impairment loss is measured as the excess of the recorded goodwill over its implied fair value. There was no impairment for the years ended December 31, 2020, 2019 or 2018.
Fair Value of Financial Instruments	Fair Value of Financial Instruments The carrying amounts of certain financial instruments including cash and cash equivalents, accounts receivable, prepaid expenses and other current assets, accounts payable and accrued liabilities approximate fair value due to their relatively short maturities.
Revenue Recognition and Cost of Revenue	Revenue Recognition Testing Revenue The Company recognizes testing revenue in accordance with the provisions of ASC 606, Revenue from Contracts with Customers , or ASC 606. Most of the Company’s revenue is generated from the provision of testing services. These services are completed upon the delivery of test results to the prescribing physician, at which time the Company bills for the services. The Company recognizes revenue related to billings based on estimates of the amount that will ultimately be realized. In determining the amount to accrue for a delivered test, the Company considers factors such as payment history, payer coverage, whether there is a reimbursement contract between the payer and the Company, payment as a percentage of agreed upon rate (if applicable), amount paid per test and any current developments or changes that could impact reimbursement. These estimates require significant judgment by management. During 2020, the Company changed its testing revenue estimates due to actual and anticipated cash collections for tests delivered in 2019 or prior years and recognized additional revenue of $1.5 million, which resulted in a decrease in the Company's loss from operations of $1.5 million and a decrease in loss per share of $0.02 for the year ended December 31, 2020. During 2019, the Company changed its testing revenue estimates due to actual and anticipated cash collections for tests delivered in 2018 or prior years and recognized additional revenue of $1.6 million, which resulted in a decrease in the Company's loss from operations of $1.6 million and a decrease in loss per share of $0.04 for the year ended December 31, 2019. During 2018, the Company changed its testing revenue estimates due to actual and anticipated cash collections for tests delivered in 2017 or prior years and recognized additional revenue of $1.4 million, which resulted in a decrease in the Company's loss from operations of $1.4 million and a decrease in loss per share of $0.04 for the year ended December 31, 2018. Product Revenue The Company began recognizing product revenue in December 2019, when the Company executed an agreement with NanoString for the exclusive global license to the nCounter Analysis System for diagnostic use. More details on this agreement are in Note 4. Business Combination. Product revenue from instruments and diagnostic kits is recognized generally upon shipment or when the instrument is ready for use by the end customer, which is when title of the product has been transferred to the customer. This process involves identifying the contract with a customer, determining the performance obligations in the contract, determining the contract price, allocating the contract price to the distinct performance obligations in the contract, and recognizing revenue when the performance obligations have been satisfied. A performance obligation is considered distinct from other obligations in a contract when it provides a benefit to the customer either on its own or together with other resources that are readily available to the customer and is separately identified in the contract. Performance obligations are considered satisfied once the Company has transferred control of a product to the customer, meaning the customer has the ability to use and obtain the benefit of the product. The Company recognizes product revenue for satisfied performance obligations only when there are no uncertainties regarding payment terms or transfer of control. Shipping and handling costs incurred for product shipments are charged to the Company's customers and included in product revenue. Revenues are presented net of the taxes that are collected from customers and remitted to governmental authorities. There was no revenue from instrument sales for the years ended December 31, 2020, 2019 or 2018. Biopharmaceutical and Collaboration Revenue From time to time, the Company enters into arrangements for research and development and/or commercialization services. Such arrangements may require the Company to deliver various rights, services and/or samples, including intellectual property rights/licenses, R&D services, and/or commercialization services. The underlying terms of these arrangements generally provide for consideration to the Company in the form of nonrefundable upfront license fees, development and commercial performance milestone payments, royalty payments, and/or profit sharing. Net sales of data or other services to customers are recognized in accordance with ASC 606 and are classified under biopharmaceutical revenue. Certain milestone payments fall under the scope of ASC Topic 808, Collaborative Arrangements , or ASC 808, and are classified under collaboration revenue. Payments received that are not sales or services to a customer or collaboration revenue are recorded as offsets against research and development expense in the Company's consolidated statements of operations and comprehensive loss. In arrangements involving more than one performance obligation, each required performance obligation is evaluated to determine whether it qualifies as a distinct performance obligation based on whether (i) the customer can benefit from the good or service either on its own or together with other resources that are readily available and (ii) the good or service is separately identifiable from other promises in the contract. The consideration under the arrangement is then allocated to each separate distinct performance obligation based on its respective relative stand-alone selling price. The estimated selling price of each deliverable reflects the Company's best estimate of what the selling price would be if the deliverable was regularly sold by the Company on a stand-alone basis or using an adjusted market assessment approach if selling price on a stand-alone basis is not available. The consideration allocated to each distinct performance obligation is recognized as revenue when control of the related goods is transferred or services are performed. Consideration associated with at-risk substantive performance milestones is recognized as revenue when it is probable that a significant reversal of the cumulative revenue recognized will not occur. Should there be royalties, the Company utilizes the sales and usage-based royalty exception in arrangements that resulted from the license of intellectual property, recognizing revenues generated from royalties or profit sharing as the underlying sales occur. As part of the accounting for these arrangements, the Company must develop estimates and assumptions that require judgment to determine the underlying stand-alone selling price for each performance obligation which determines how the transaction price is allocated among the performance obligations. Generally, the estimation of the stand-alone selling price may include such estimates as independent evidence of market price, forecasted revenues or costs, development timelines, discount rates, and probabilities of technical and regulatory success. The Company evaluates each performance obligation to determine if they can be satisfied at a point in time or over time, and it measures the services delivered to the collaborative partner which are periodically reviewed based on the progress of the related program. The effect of any change made to an estimated input component and, therefore revenue or expense recognized, would be recorded as a change in estimate. In addition, variable consideration must be evaluated to determine if it is constrained and, therefore, excluded from the transaction price. Up-front Fees: If a license to the Company’s intellectual property is determined to be distinct from the other performance obligations identified in the arrangement, the Company recognizes revenues from the transaction price allocated to the license when the license is transferred to the licensee and the licensee is able to use and benefit from the license. For licenses that are bundled with other promises, the Company utilizes judgment to assess the nature of the combined performance obligation to determine whether the combined performance obligation is satisfied over time or at a point in time. Milestone Payments: At the inception of each arrangement that includes milestone payments (variable consideration), the Company evaluates whether the milestones are considered probable of being reached and estimates the amount to be included in the transaction price using the most likely amount method. If it is probable that a significant revenue reversal would not occur, the associated milestone value is included in the transaction price. Milestone payments that are not within the Company’s or the collaborative partner’s control, such as non-operational developmental and regulatory approvals, are generally not considered probable of being achieved until those approvals are received. At the end of each reporting period, the Company re-evaluates the probability of achievement of milestones that are within its or the collaborative partner’s control, such as operational developmental milestones and any related constraint, and if necessary, adjusts its estimate of the overall transaction price. Any such adjustments are recorded on a cumulative catch-up basis, which would affect collaboration revenues and earnings in the period of adjustment. Revisions to the Company’s estimate of the transaction price may also result in negative collaboration revenues and earnings in the period of adjustment. Diagnostic Development Agreements with Johnson & Johnson The Company has entered into contracts with the Lung Cancer Initiative at Johnson & Johnson to cooperate on the development of clinical data, to provide data generated by the Company and to license the right to use data under the Company's intellectual property rights. Under the terms of the agreements, the Company will provide data in exchange for up to $18.0 million in payments from Johnson & Johnson. The Company is also entitled to additional payments of up to $13.0 million, conditioned upon the achievement of certain milestones. The agreements are considered to be within the scope of ASC 808 with respect to the milestone payments, as the parties are active participants and exposed to the risks and rewards of the collaborative activity. The delivery of data under the collaborative arrangement, which the Company believes is a distinct service for which Johnson & Johnson meets the definition of a customer is within the scope of ASC 606. Using the concepts of ASC 606, the Company has identified the delivery of data as its only performance obligation. The grant of the license is not distinct from other performance obligations as the customer receives benefit only when other performance obligations are met. The Company further determined that the transaction prices under the arrangements are the $18.0 million in payments which was allocated to the obligation to deliver data. The $13.0 million in future potential payments is considered variable consideration because the Company determined that the potential payments are contingent upon regulatory and commercialization milestones that are uncertain to occur and, as such, were not included in the transaction price, and will be recognized accordingly as each potential payment becomes probable. The Company recognized revenue of $1.5 million and $7.0 million for the years ended December 31, 2020 and 2019, respectively, for the provision of data classified under biopharmaceutical revenue. The Company recognized revenue of zero and $4.0 million for the years ended December 31, 2020 and 2019, respectively, for the fulfillment of obligations relating to development milestones classified under collaboration revenue in the consolidated statement of operations and comprehensive loss. Accounts receivable from these contracts was zero and $2.0 million at December 31, 2020 and 2019, respectively. A payment of $950,000 received by the Company was classified as deferred revenue in the consolidated balance sheet at December 31, 2020. There was no deferred revenue related to these agreements at December 31, 2019. Other Collaboration and Service Agreements The Company has entered into agreements with biopharmaceutical companies and other diagnostic companies to provide them with data, development services and the right to develop tests on the nCounter Analysis System. For the year ended December 31, 2020 the Company recognized biopharmaceutical revenue of $1.0 million for the sale of commercial and development rights and $2.8 million for development services. For the year ended December 31, 2019 the Company recognized biopharmaceutical revenue of $1.0 million for development services and $0.1 million for the delivery of data. For the year ended December 31, 2018 the Company recognized biopharmaceutical revenue of $0.5 million for development services and $0.5 million for the delivery of data. Accounts receivable from these contracts was $0.4 million and zero at December 31, 2020 and 2019, respectively. As of December 31, 2020, the Company had received a payment of $0.3 million related to these contracts which is included in deferred revenue. Cost of Testing Revenue The components of the Company's cost of testing services are laboratory expenses, sample collection expenses, compensation expense, license fees and royalties, depreciation and amortization, other expenses such as equipment and laboratory supplies, and allocations of facility and information technology expenses. Costs associated with performing tests are expensed as the test is processed regardless of whether and when revenue is recognized with respect to that test. Cost of testing revenue for the year ended December 31, 2020 included a $1.1 million write-down of supplies for the expiration of reagents due to an anticipated decline in volumes resulting from the COVID-19 pandemic. Cost of Product Revenue Cost of product revenue consists primarily of costs of purchasing instruments and diagnostic kits from third-party contract manufacturers, installation, service and packaging and delivery costs. In addition, cost of product includes royalty costs for licensed technologies included in the Company’s products and labor expenses. Cost of product revenue for instruments and diagnostic kits is recognized in the period the related revenue is recognized. Shipping and handling costs incurred for product shipments are included in cost of product in the consolidated statements of operations and comprehensive loss. Cost of Biopharmaceutical Revenue Cost of biopharmaceutical revenue consists of costs of performing activities under arrangements that require the Company to perform research and development services on behalf of a customer pursuant to a biopharmaceutical service agreement.
Research and Development	Research and DevelopmentResearch and development expenses include expenses incurred to develop the Company's technology, collect clinical samples and conduct clinical studies to develop and support its products. These expenses consist of compensation expenses, direct research and development expenses such as prototype materials, laboratory supplies and costs associated with setting up and conducting clinical studies at domestic and international sites, professional fees, depreciation and amortization, other miscellaneous expenses and allocation of facility and information technology expenses. The Company expenses all research and development costs in the periods in which they are incurred.
Income Taxes	Income Taxes The Company accounts for income taxes under the liability method. Under this method, deferred tax assets and liabilities are determined based on the difference between the financial statement and tax bases of assets and liabilities using enacted tax rates in effect for the year in which the differences are expected to affect taxable income. Valuation allowances are established when necessary to reduce deferred tax assets to the amounts expected to be realized. The Company assesses all material positions taken in any income tax return, including all significant uncertain positions, in all tax years that are still subject to assessment or challenge by relevant taxing authorities. The Company's assessment of an uncertain tax position begins with the initial determination of the position's sustainability and is measured at the largest amount of benefit that is more-likely-than-not of being realized upon ultimate settlement. As of each balance sheet date, unresolved uncertain tax positions must be reassessed, and the Company will determine whether (i) the factors underlying the sustainability assertion have changed and (ii) the amount of the recognized tax benefit is still appropriate. The recognition and measurement of tax benefits requires significant judgment. Judgments concerning the recognition and measurement of a tax benefit may change as new information becomes available.
Stock-based Compensation	Stock-based Compensation Stock-based compensation expense for stock options issued to employees is measured based on the grant-date fair value of the award. The fair value of each employee stock option is estimated on the date of grant using the Black-Scholes option-pricing model. Stock-based compensation expense for stock units is measured based on the fair value of the award, which is determined based upon the closing price of the Company’s common stock on the date of the grant. The Company grants performance-based stock units to certain employees which vest upon the achievement of certain performance conditions, subject to the employees’ continued service with the Company. The probability of vesting is assessed at each reporting period and compensation cost is adjusted based on this probability assessment. The Company recognizes compensation costs on a straight-line basis for all employee stock-based compensation awards that are expected to vest over the requisite service period of the awards, which is generally the awards' vesting period. Forfeitures are required to be estimated at the time of grant and revised, if necessary, in subsequent periods if actual forfeitures differ from those estimates. Following the adoption of ASU No. 2018-07, Compensation - Stock Compensation (Topic 718): Improvements to Nonemployee Share Based Payment Accounting
Net Loss per Common Share	Net Loss per Common Share Basic net loss per common share is calculated by dividing net loss attributable to common stockholders by the weighted-average number of common shares outstanding during the period, without consideration of common stock equivalents. Diluted net loss per common share is computed by dividing net loss attributable to common stockholders by the weighted-average number of common share equivalents outstanding for the period determined using the treasury stock method. Potentially dilutive securities consisting of options to purchase common stock, restricted stock units and shares subject to purchase under our employee stock purchase plan are considered to be common stock equivalents and were excluded from the calculation of diluted net loss per common share because their effect would be anti-dilutive for all periods presented.
Segment Reporting	Segment Reporting The chief operating decision maker for the Company is the Chief Executive Officer, who reviews financial information presented on a consolidated basis for purposes of allocating resources and assessing financial performance. The Company has a single reporting unit associated with the development and commercialization of diagnostic products. Revenue by geographic region based on the customer billing address was as follows (in thousands): Year Ended December 31, 2020 2019 2018 United States $ 109,614 $ 119,153 $ 91,773 International 7,869 1,215 235 Total revenue $ 117,483 $ 120,368 $ 92,008 All of the Company’s long-lived assets were located in the United States as of December 31, 2020 and 2019.
Recent Accounting Pronouncements	Recent Accounting Pronouncements In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments—Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments . This ASU requires entities to estimate an expected lifetime credit loss on financial assets ranging from short-term trade accounts receivable to long-term financings and report credit losses using an expected losses model rather than the incurred losses model that was previously used, and establishes additional disclosures related to credit risks. This guidance became effective for the Company beginning January 1, 2020. Based on the composition of its trade receivables, investment portfolio and other financial assets, current economic conditions and historical credit loss activity, the adoption of this standard did not have a material impact on the Company's consolidated financial statements and related disclosures. In August 2018 the FASB issued ASU No. 2018-15, Intangibles—Goodwill and Other—Internal-Use Software (Subtopic 350-40): Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract . This standard clarifies the accounting for implementation costs in cloud computing arrangements by aligning the accounting for costs incurred to implement a cloud computing arrangement that is a service arrangement with the guidance on capitalizing costs associated with developing or obtaining internal-use software. This standard became effective for the Company on January 1, 2020 and was adopted on a prospective basis with no material impact on the Company's consolidated financial statements. In August 2018, the FASB issued ASU No. 2018-13, Fair Value Measurement (Topic 820), Disclosure Framework—Changes to the Disclosure Requirements for Fair Value Measurement , or ASU 2018-13. ASU 2018-13 removed the following disclosure requirements: (1) the amount of and reasons for transfers between Level 1 and Level 2 of the fair value hierarchy; (2) the policy for timing of transfers between levels; and (3) the valuation processes for Level 3 fair value measurements. Additionally, this update added the following disclosure requirements: (1) the changes in unrealized gains and losses for the period included in other comprehensive income and loss for recurring Level 3 fair value measurements held at the end of the reporting period; (2) the range and weighted average of significant unobservable inputs used to develop Level 3 fair value measurements. For certain unobservable inputs, an entity may disclose other quantitative information (such as the median or arithmetic average) in lieu of the weighted average if the entity determines that other quantitative information would be a more reasonable and rational method to reflect the distribution of unobservable inputs used to develop Level 3 fair value measurements. ASU 2018-13 became effective for the Company beginning January 1, 2020 and the adoption of ASU 2018-13 did not have a material impact on the Company’s consolidated financial statements. For the disclosures regarding the Company’s Level 3 fair value measurements, see Note 6. Fair Value Measurements to these consolidated financial statements.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	12 Months Ended
Summary of Significant Accounting Policies (Tables)	Dec. 31, 2020
Accounting Policies [Abstract]
Schedule of the Company's third-party payers as a percentage of total	The Company's third-party payers and other customers in excess of 10% of revenue and their related revenue as a percentage of total revenue were as follows: Year Ended December 31, 2020 2019 2018 Medicare 24 % 26 % 29 % UnitedHealthcare 11 % 11 % 12 % 35 % 37 % 41 % The Company's significant third-party payers and other customers in excess of 10% of total accounts receivable and their related accounts receivable balance as a percentage of total accounts receivable were as follows: As of December 31, 2020 2019 Medicare 13 % 15 % UnitedHealthcare 12 % 9 % Johnson and Johnson Services, Inc. * 10 % * less than 10%
Schedule of Revenue	Revenue by geographic region based on the customer billing address was as follows (in thousands): Year Ended December 31, 2020 2019 2018 United States $ 109,614 $ 119,153 $ 91,773 International 7,869 1,215 235 Total revenue $ 117,483 $ 120,368 $ 92,008

Net Loss Per Share (Tables)

Net Loss Per Share (Tables)	12 Months Ended
Net Loss Per Share (Tables)	Dec. 31, 2020
Earnings Per Share [Abstract]
Schedule of outstanding common stock equivalents excluded from diluted net loss per common share	The following outstanding common stock equivalents have been excluded from diluted net loss per common share for the years ended December 31, 2020, 2019 and 2018 because their inclusion would be anti-dilutive: Year Ended December 31, 2020 2019 2018 Shares of common stock subject to outstanding options 4,564,777 5,394,944 5,998,163 Employee stock purchase plan 21,006 26,124 34,869 Restricted stock units 913,562 712,122 384,691 Total common stock equivalents 5,499,345 6,133,190 6,417,723

Business Combination (Tables)

Business Combination (Tables)	12 Months Ended
Business Combination (Tables)	Dec. 31, 2020
Business Combinations [Abstract]
Schedule of fair value of assets acquired and liabilities assumed	The following table summarizes the fair values of assets acquired and liabilities assumed at the date of acquisition (in thousands of dollars): Prosigna product technology $ 4,120 Prosigna customer relationships 2,430 nCounter Dx license 46,880 LymphMark product technology 990 Total identifiable intangible assets acquired 54,420 Goodwill 1,668 Net assets acquired $ 56,088
Schedule of estimated useful life for identifiable acquisition-related intangibles	Identifiable acquisition-related intangibles included in the above table are finite-lived and are being amortized on a straight-line basis over their estimated lives, which approximates the pattern in which the economic benefits of the intangible assets are expected to be realized, as follows: Estimated Useful life (In Years) Prosigna product technology 15 Prosigna customer relationships 5 nCounter Dx license 15 LymphMark product technology 7
Unaudited pro forma revenue information	The unaudited pro forma revenue information is for informational purposes only and is not necessarily indicative of the revenue that would have been achieved if the acquisition had taken place as of January 1, 2018 (in thousands of dollars): Year Ended December 31, 2019 2018 Product revenue $ 11,040 $ 11,482

Balance Sheet Components (Table

Balance Sheet Components (Tables)	12 Months Ended
Balance Sheet Components (Tables)	Dec. 31, 2020
Balance Sheet Related Disclosures [Abstract]
Schedule of property and equipment	Property and equipment consisted of the following (in thousands of dollars): December 31, 2020 2019 Leasehold improvements $ 6,863 $ 5,926 Laboratory equipment 10,643 9,655 Computer equipment 1,783 1,709 Software, including software developed for internal use 3,793 3,226 Furniture and fixtures 1,544 1,482 Construction-in-process 761 1,015 Total property and equipment, at cost 25,387 23,013 Accumulated depreciation and amortization (16,397) (14,080) Total property and equipment, net $ 8,990 $ 8,933
Schedule of finite-lived intangible assets	Finite-live intangible assets consisted of the following (in thousands of dollars): December 31, 2020 December 31, 2019 Weighted Average Amortization Period (Years) Gross Carrying Amount Accumulated Amortization Net Carrying Amount Gross Carrying Amount Accumulated Amortization Net Carrying Amount Percepta product technology $ 16,000 $ (6,133) $ 9,867 $ 16,000 $ (5,067) $ 10,933 15 Prosigna product technology 4,120 (298) 3,822 4,120 (17) 4,103 15 Prosigna customer relationships 2,430 (526) 1,904 2,430 (42) 2,388 5 nCounter Dx license 46,880 (3,386) 43,494 46,880 (263) 46,617 15 LymphMark product technology 990 (153) 837 990 (12) 978 7 Total $ 70,420 $ (10,496) $ 59,924 $ 70,420 $ (5,401) $ 65,019 14.6
Schedule of future aggregate amortization expense	The estimated future aggregate amortization expense as of December 31, 2020 is as follows (in thousands of dollars): Year Ending December 31, Amounts 2021 $ 5,094 2022 5,094 2023 5,094 2024 5,054 2025 4,608 Thereafter 34,980 Total $ 59,924
Schedule of accrued liabilities	Accrued liabilities consisted of the following (in thousands of dollars): December 31, 2020 2019 Accrued compensation expense $ 9,201 $ 10,100 Accrued other 2,504 3,634 Total accrued liabilities $ 11,705 $ 13,734

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
Fair Value Measurements (Tables)	Dec. 31, 2020
Fair Value Disclosures [Abstract]
Schedule of fair value measurement unobservable inputs	As of December 31, 2020, the Company calculated the estimated fair value of the milestones using the following significant unobservable inputs: Value or Range Unobservable input (Weighted-Average) Discount rate 6.9% Probability of achievement 70% - 100% (86%)

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
Commitments and Contingencies (Tables)	Dec. 31, 2020
Commitments and Contingencies Disclosure [Abstract]
Schedule of future minimum lease payments under non-cancelable operating leases	Future minimum lease payments under non-cancelable operating leases as of December 31, 2020 are as follows (in thousands of dollars): Year Ending December 31, Amounts 2021 $ 2,401 2022 2,472 2023 2,543 2024 2,614 2025 2,685 Thereafter 1,542 Total future minimum lease payments 14,257 Less: amount representing interest 2,751 Present value of future lease payments 11,506 Less: short-term lease liabilities 1,589 Long-term lease liabilities $ 9,917

Debt (Tables)

Debt (Tables)	12 Months Ended
Debt (Tables)	Dec. 31, 2020
Debt Disclosure [Abstract]
Schedule of net debt obligation	As of December 31, 2020 and 2019, the net debt obligation for borrowings made under the Loan and Security Agreement was as follows (in thousands of dollars): December 31, 2020 2019 Debt principal $ — $ 100 End-of-term debt obligation 810 594 Net debt obligation $ 810 $ 694
Schedule of interest expense on debt	Interest expense was recognized as follows (in thousands of dollars): Year Ended December 31, 2020 2019 2018 Nominal debt interest $ 13 $ 332 $ 1,568 Amortization and write-off of debt discount and issuance costs — 107 57 End-of-term debt obligation interest 216 229 312 Interest on capital lease — 9 26 Total $ 229 $ 677 $ 1,963

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	12 Months Ended
Stockholders' Equity (Tables)	Dec. 31, 2020
Equity [Abstract]
Schedule of reserved shares of common stock for issuance	As of December 31, 2020 and 2019, the Company had reserved shares of common stock for issuance as follows: December 31, 2020 2019 Stock options and restricted stock units issued and outstanding 4,867,303 5,562,484 Stock options and restricted stock units available for grant under stock option plans 3,061,589 1,954,804 Common stock available for the Employee Stock Purchase Plan 1,571,395 173,168 Total 9,500,287 7,690,456

Stock Incentive Plans (Tables)

Stock Incentive Plans (Tables)	12 Months Ended
Stock Incentive Plans (Tables)	Dec. 31, 2020
Stock incentive plans
Schedule of activity under the Company's stock incentive plans	The following table summarizes activity under the Company's stock incentive plans (aggregate intrinsic value in thousands): Shares Stock Options Weighted Weighted Average Aggregate Balance—December 31, 2019 1,954,804 5,562,484 $ 10.66 6.97 $ 79,760 Additional shares authorized 1,985,013 — Granted - stock options (983,900) 983,900 26.40 Granted - restricted stock units (451,709) 451,709 Canceled 421,558 (421,558) 6.51 Exercised — (1,345,134) 8.67 Restricted stock units vested — (364,098) Tax portion of restricted stock units vested 135,823 — Balance—December 31, 2020 3,061,589 4,867,303 $ 15.14 6.98 $ 135,879 Options vested and exercisable—December 31, 2020 2,316,166 $ 10.35 5.78 $ 89,376 Options vested and expected to vest—December 31, 2020 3,858,859 $ 14.78 6.91 $ 131,816
Stock-based Compensation
Stock incentive plans
Schedule of share-based compensation expense	The following table summarizes stock-based compensation expense related to stock options, restricted stock units and the ESPP for the years ended December 31, 2020, 2019 and 2018, and are included in the consolidated statements of operations and comprehensive loss as follows (in thousands of dollars): Year Ended December 31, 2020 2019 2018 Cost of testing revenue $ 369 $ 277 $ 130 Research and development 2,690 1,856 1,018 Selling and marketing 3,474 2,938 1,866 General and administrative 6,462 4,736 2,944 Total stock-based compensation expense $ 12,995 $ 9,807 $ 5,958
Stock-based Compensation, employees
Stock incentive plans
Schedule of assumptions used to calculate fair value of stock options using the Black-Scholes model	The estimated grant-date fair value of employee stock options using the Black-Scholes option-pricing model was based on the following assumptions: Year Ended December 31, 2020 2019 2018 Weighted-average volatility 54.40 - 58.20% 52.90 - 53.40% 50.40 - 52.70% Weighted-average expected term (years) 5.24 - 5.42 5.50 - 6.08 5.50 - 6.08 Risk-free interest rate 0.24 - 0.92% 1.90 - 2.60% 2.40 - 3.10% Expected dividend yield — — —
Stock-based Compensation, non-employees
Stock incentive plans
Schedule of assumptions used to calculate fair value of stock options using the Black-Scholes model	The estimated fair value of non-employee stock options using the Black-Scholes option-pricing model was based on the following assumptions: Year Ended December 31, 2020 2019 2018 Weighted-average volatility —% —% 43.60 - 50.50% Weighted-average expected term (years) — — 0.25 - 6.75 Risk-free interest rate —% —% 1.84 - 2.87% Expected dividend yield — — —
Employee stock purchase plan
Stock incentive plans
Schedule of assumptions used to calculate fair value of stock options using the Black-Scholes model	The estimated grant date fair value of the ESPP shares was calculated using the Black-Scholes option-pricing model, based on the following assumptions: Year Ended December 31, 2020 2019 2018 Weighted-average volatility 54.16 - 85.01% 53.38 - 71.77% 42.88 - 47.74% Weighted-average expected term (years) 0.50 - 1.00 0.50 - 1.00 0.50 - 1.00 Risk-free interest rate 0.11 - 1.56% 1.88 - 2.56% 1.64 - 2.45% Expected dividend yield — — —

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
Income Taxes (Tables)	Dec. 31, 2020
Income Tax Disclosure [Abstract]
Schedule of reconciliation of tax expense computed at the statutory federal rate	The following table presents a reconciliation of the income tax expense computed at the statutory federal rate and the Company's income tax expense for the periods presented (in thousands of dollars): Year Ended December, 31, 2020 2019 2018 U.S. federal taxes at statutory rate $ (7,302) $ (2,632) $ (4,825) State tax (net of federal benefit) (1,794) (828) — Foreign rate differential 1 — — Non deductible officers' compensation 1,443 439 409 Permanent differences 131 221 285 Stock based compensation including excess tax benefit (4,881) (4,366) (256) Tax credits (588) (996) (777) Change in valuation allowance 12,990 8,162 5,164 Total $ — $ — $ —
Schedule of significant components of the Company's deferred tax assets and liabilities	Significant components of the Company's deferred tax assets and liabilities are as follows (in thousands of dollars): Year Ended December 31, 2020 2019 2018 Deferred tax assets: Net operating loss carryforwards $ 68,113 $ 56,506 $ 50,410 Research and development credits 6,167 5,579 4,584 Stock-based compensation 2,696 2,246 1,032 NanoString intangibles and goodwill 908 380 — Operating lease liability 2,826 3,068 — Accruals and other 2,623 2,610 2,918 Gross deferred tax assets 83,333 70,389 58,944 Valuation allowance (78,650) (65,228) (55,366) Net deferred tax assets 4,683 5,161 3,578 Deferred tax liabilities: Property and equipment (334) (471) (695) In-process research and development (2,423) (2,597) (2,883) ROU assets (1,926) (2,093) — Gross deferred tax liabilities (4,683) (5,161) (3,578) Net deferred tax liabilities (4,683) (5,161) (3,578) Net deferred taxes $ — $ — $ —
Schedule of reconciliation of unrecognized tax benefits	A reconciliation of the beginning and ending amount of unrecognized tax benefits is as follows (in thousands of dollars): Year Ended December 31, 2020 2019 2018 Unrecognized tax benefits, beginning of period $ 3,278 $ 2,799 $ 2,523 Gross increases—tax position in prior period — — — Gross decreases—tax position in prior period — — (97) Gross increases—current period tax position 285 479 373 Lapse of statute of limitations — — — Unrecognized tax benefits, end of period $ 3,563 $ 3,278 $ 2,799

Selected Quarterly Financial _2

Selected Quarterly Financial Data (Unaudited) (Tables)	12 Months Ended
Selected Quarterly Financial Data (Unaudited) (Tables)	Dec. 31, 2020
Quarterly Financial Information Disclosure [Abstract]
Schedule of selected quarterly financial data (unaudited)	The results of operations for any quarter are not necessarily indicative of the results to be expected for any future period (in thousands of dollars, except for share and per share data): Quarter Ended March 31 June 30 September 30 December 31 2020: Revenue $ 31,122 $ 20,704 $ 31,121 $ 34,536 Net loss (11,716) (11,025) (4,124) (8,044) Net loss per common share, basic and diluted (0.24) (0.22) (0.08) (0.14) Shares used to compute net loss per common share, basic and diluted 49,792,631 50,212,123 54,858,052 58,023,753 2019: Revenue $ 29,529 $ 30,136 $ 30,973 $ 29,730 Net loss (1,917) (2,494) (730) (7,458) Net loss per common share, basic and diluted (0.05) (0.05) (0.02) (0.15) Shares used to compute net loss per common share, basic and diluted 41,168,593 45,586,081 48,588,296 49,095,703

Organization and Description _2

Organization and Description of Business (Details)	12 Months Ended
Organization and Description of Business (Details)	Dec. 31, 2020segmentdiseaseAreas
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of operating segments \| segment	1
Number of disease areas with genomic testing \| diseaseAreas	4

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Reclassifications & Liquidity (Details) - USD ($) $ / shares in Units, $ in Thousands	Feb. 09, 2021	Feb. 22, 2021	Aug. 31, 2020	May 31, 2019	Jul. 31, 2018	Nov. 30, 2017	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Liquidity
Accumulated deficit							$ 281,594	$ 246,685
Cash and cash equivalents							349,364	159,317	$ 77,995
Cash paid for acquisition							$ 0	40,000	$ 0
Number of shares issued in transaction (in shares)			6,900,000	6,325,000	5,750,000
Proceeds from issuance of common stock			$ 193,800	$ 137,800	$ 55,000
Payments of stock issuance costs			$ 13,200	$ 9,200	$ 3,900
Subsequent Event
Liquidity
Number of shares issued in transaction (in shares)	8,547,297
Proceeds from issuance of common stock	$ 593,800
Payments of stock issuance costs	$ 38,700
Decipher Biosciences \| Subsequent Event
Liquidity
Cash paid for acquisition		$ 600,000
Revolving credit facility \| Line of credit \| Silicon Valley Bank
Liquidity
Proceeds from long-term lines of credit						$ 25,000
Over-Allotment Option
Liquidity
Number of shares issued in transaction (in shares)			900,000	825,000	750,000
Over-Allotment Option \| Subsequent Event
Liquidity
Number of shares issued in transaction (in shares)	1,114,864
Common Stock
Liquidity
Shares issued, price per share (in USD per share)			$ 30	$ 23.25	$ 10.25
Common Stock \| Subsequent Event
Liquidity
Shares issued, price per share (in USD per share)	$ 74
Revision of Prior Period, Adjustment
Liquidity
Reclassification of operating assets and liabilities to noncash lease expense								$ 1,000

Summary of Significant Accoun_5

Summary of Significant Accounting Policies - Credit Risk, Cash Equivalents, and Restricted Cash (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2020USD ($)financial_institution	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)
Concentrations of Credit Risk and Other Risks and Uncertainties
Number of major financial institutions \| financial_institution	1
Restricted Cash
Long term deposit consisting of letter of credit serving as security for lease \| $	$ 603	$ 603	$ 603
Overnight Reverse Repurchase Agreements
Cash Equivalents
Cash equivalents collateralized by US treasury (percentage)	102.00%
Revenue \| Revenue concentration risk
Concentrations of Credit Risk and Other Risks and Uncertainties
Concentration risk	35.00%	37.00%	41.00%
Revenue \| Revenue concentration risk \| Medicare
Concentrations of Credit Risk and Other Risks and Uncertainties
Concentration risk	24.00%	26.00%	29.00%
Revenue \| Revenue concentration risk \| United Healthcare
Concentrations of Credit Risk and Other Risks and Uncertainties
Concentration risk	11.00%	11.00%	12.00%
Accounts receivable \| Gross receivables concentration risk \| Medicare
Concentrations of Credit Risk and Other Risks and Uncertainties
Concentration risk	13.00%	15.00%
Accounts receivable \| Gross receivables concentration risk \| United Healthcare
Concentrations of Credit Risk and Other Risks and Uncertainties
Concentration risk	12.00%	9.00%
Accounts receivable \| Gross receivables concentration risk \| Johnson and Johnson Services, Inc.
Concentrations of Credit Risk and Other Risks and Uncertainties
Concentration risk		10.00%

Summary of Significant Accoun_6

Summary of Significant Accounting Policies - Equity Investments, Tangible and Intangible Assets, Goodwill, and Revenue Recognition (Details) - USD ($)	Dec. 28, 2018	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Jul. 31, 2020
Accounts, Notes, Loans and Financing Receivable [Line Items]
Investment in MAVIDx													$ 1,000,000
Impairment loss		$ 1,000,000								$ 1,000,000	$ 0	$ 0
Finite-lived Intangible Assets
Weighted Average Amortization Period (Years)										14 years 7 months 6 days
Finite-lived intangible assets, impairment										$ 0	0	0
Goodwill
Goodwill impairment										0	0	0
Revenue Recognition
Income (loss) from operations										$ (35,389,000)	$ (15,127,000)	$ (22,233,000)
Net income (loss) per common share, basic and diluted (in USD per share)		$ (0.14)	$ (0.08)	$ (0.22)	$ (0.24)	$ (0.15)	$ (0.02)	$ (0.05)	$ (0.05)	$ (0.66)	$ (0.27)	$ (0.62)
Revenue from contract with customer, excluding assessed tax		$ 34,536,000	$ 31,121,000	$ 20,704,000	$ 31,122,000	$ 29,730,000	$ 30,973,000	$ 30,136,000	$ 29,529,000	$ 117,483,000	$ 120,368,000	$ 92,008,000
Current portion of deferred revenue		371,000				0				371,000	0
Accounts receivable		18,461,000				19,329,000				18,461,000	19,329,000
Write-down of excess supplies										1,088,000	0	0
Biopharmaceutical Company \| Collaborative Arrangement
Revenue Recognition
Current portion of deferred revenue		300,000								300,000
Accounts receivable		400,000				0				400,000	0
ASU 2014-09
Revenue Recognition
Deferred revenue		1,500,000				1,600,000				1,500,000	1,600,000	1,400,000
Income (loss) from operations										$ 1,500,000	$ 1,600,000	$ 1,400,000
Net income (loss) per common share, basic and diluted (in USD per share)										$ 0.02	$ 0.04	$ 0.04
Minimum
Accounts, Notes, Loans and Financing Receivable [Line Items]
Useful lives (in years)										3 years
Finite-lived Intangible Assets
Weighted Average Amortization Period (Years)										5 years
Maximum
Accounts, Notes, Loans and Financing Receivable [Line Items]
Useful lives (in years)										5 years
Finite-lived Intangible Assets
Weighted Average Amortization Period (Years)										15 years
Service \| Biopharmaceutical Company \| Collaborative Arrangement
Revenue Recognition
Contract with customer, revenue recognized										$ 2,800,000	$ 1,000,000	$ 500,000
Product
Revenue Recognition
Revenue from contract with customer, excluding assessed tax										9,845,000	923,000	0
Product \| Biopharmaceutical Company \| Collaborative Arrangement
Revenue Recognition
Contract with customer, revenue recognized											100,000	500,000
Testing
Revenue Recognition
Revenue from contract with customer, excluding assessed tax										101,970,000	107,355,000	$ 91,058,000
Testing \| Cost of testing revenue \| COVID 19 Pandemic
Revenue Recognition
Write-down of excess supplies										1,100,000
Commercial and Development Rights \| Biopharmaceutical Company \| Collaborative Arrangement
Revenue Recognition
Contract with customer, revenue recognized										1,000,000
Johnson and Johnson Services, Inc. \| Collaborative Arrangement
Revenue Recognition
Collaborative agreement contingent receivable amount	$ 13,000,000
Contract with customer, revenue recognized										0	4,000,000
Accounts receivable, before allowance for credit loss		0				2,000,000				0	2,000,000
Current portion of deferred revenue		$ 950,000				$ 0				950,000	0
Johnson and Johnson Services, Inc. \| Provision of Data \| Collaborative Arrangement
Revenue Recognition
Collaborative agreement amount	18,000,000
Contract agreement receivable for services	$ 18,000,000
Revenue from contract with customer, excluding assessed tax										$ 1,500,000	$ 7,000,000

Summary of Significant Accoun_7

Summary of Significant Accounting Policies - Segment Reporting (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Disaggregation of Revenue [Line Items]
Total revenue	$ 34,536	$ 31,121	$ 20,704	$ 31,122	$ 29,730	$ 30,973	$ 30,136	$ 29,529	$ 117,483	$ 120,368	$ 92,008
United States
Disaggregation of Revenue [Line Items]
Total revenue									109,614	119,153	91,773
International
Disaggregation of Revenue [Line Items]
Total revenue									$ 7,869	$ 1,215	$ 235

Net Loss Per Share (Details)

Net Loss Per Share (Details) - shares	12 Months Ended
Net Loss Per Share (Details) - shares	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Outstanding shares of common stock equivalents that have been excluded from diluted net loss per common share
Shares of common stock subject to outstanding options (in shares)	5,499,345	6,133,190	6,417,723
Shares of common stock subject to outstanding options
Outstanding shares of common stock equivalents that have been excluded from diluted net loss per common share
Shares of common stock subject to outstanding options (in shares)	4,564,777	5,394,944	5,998,163
Employee stock purchase plan
Outstanding shares of common stock equivalents that have been excluded from diluted net loss per common share
Shares of common stock subject to outstanding options (in shares)	21,006	26,124	34,869
Restricted stock units
Outstanding shares of common stock equivalents that have been excluded from diluted net loss per common share
Shares of common stock subject to outstanding options (in shares)	913,562	712,122	384,691

Business Combination - Addition

Business Combination - Additional Information (Details) - USD ($) $ in Thousands	Dec. 03, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Business Combination
Value of shares issued in acquisition		$ 0	$ 10,000	$ 0
Acquisition related contingent consideration		7,594	6,088
Acquisition related goodwill		2,725	$ 2,725
NanoString
Business Combination
Cash paid in acquisition	$ 40,000
Additional cash to be paid	10,000
Acquisition related contingent consideration	6,100	$ 7,600
Acquisition related goodwill	1,668
Common Stock \| NanoString
Business Combination
Value of shares issued in acquisition	$ 10,000

Business Combination - Schedule

Business Combination - Schedule of Fair Value of Assets Acquired and Liabilities Assumed (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Dec. 03, 2019
Business Acquisition [Line Items]
Goodwill	$ 2,725	$ 2,725
NanoString
Business Acquisition [Line Items]
Total identifiable intangible assets acquired			$ 54,420
Goodwill			1,668
Net assets acquired			56,088
Prosigna product technology \| NanoString
Business Acquisition [Line Items]
Total identifiable intangible assets acquired			4,120
Prosigna customer relationships \| NanoString
Business Acquisition [Line Items]
Total identifiable intangible assets acquired			2,430
nCounter Dx license \| NanoString
Business Acquisition [Line Items]
Total identifiable intangible assets acquired			46,880
LymphMark product technology \| NanoString
Business Acquisition [Line Items]
Total identifiable intangible assets acquired			$ 990

Business Combination - Schedu_2

Business Combination - Schedule of Identifiable Acquisition-Related Intangibles (Details) - NanoString	Dec. 03, 2019
Prosigna product technology
Business Acquisition [Line Items]
Estimated useful life	15 years
Prosigna customer relationships
Business Acquisition [Line Items]
Estimated useful life	5 years
nCounter Dx license
Business Acquisition [Line Items]
Estimated useful life	15 years
LymphMark product technology
Business Acquisition [Line Items]
Estimated useful life	7 years

Business Combination - Pro form

Business Combination - Pro forma financial information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Product revenue \| NanoString
Business Acquisition [Line Items]
Total revenue	$ 11,040	$ 11,482

Balance Sheet Components - Prop

Balance Sheet Components - Property and Equipment, Net (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Property and Equipment, Net
Total property and equipment, at cost	$ 25,387	$ 23,013
Accumulated depreciation and amortization	(16,397)	(14,080)
Total property and equipment, net	8,990	8,933
Depreciation and amortization expense	2,800	2,700	$ 2,900
Capital lease expense		1,200
Capital lease accumulated depreciation		600	367
Capital lease depreciation expense		233	$ 232
Leasehold improvements
Property and Equipment, Net
Total property and equipment, at cost	6,863	5,926
Laboratory equipment
Property and Equipment, Net
Total property and equipment, at cost	10,643	9,655
Computer equipment
Property and Equipment, Net
Total property and equipment, at cost	1,783	1,709
Software, including software developed for internal use
Property and Equipment, Net
Total property and equipment, at cost	3,793	3,226
Furniture and fixtures
Property and Equipment, Net
Total property and equipment, at cost	1,544	1,482
Construction-in-process
Property and Equipment, Net
Total property and equipment, at cost	$ 761	$ 1,015

Balance Sheet Components - Fini

Balance Sheet Components - Finite-lived Intangible Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 70,420	$ 70,420
Accumulated Amortization	(10,496)	(5,401)
Net Carrying Amount	$ 59,924	65,019
Weighted Average Amortization Period (Years)	14 years 7 months 6 days
Percepta product technology
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 16,000	16,000
Accumulated Amortization	(6,133)	(5,067)
Net Carrying Amount	$ 9,867	10,933
Weighted Average Amortization Period (Years)	15 years
Prosigna product technology
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 4,120	4,120
Accumulated Amortization	(298)	(17)
Net Carrying Amount	$ 3,822	4,103
Weighted Average Amortization Period (Years)	15 years
Prosigna customer relationships
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 2,430	2,430
Accumulated Amortization	(526)	(42)
Net Carrying Amount	$ 1,904	2,388
Weighted Average Amortization Period (Years)	5 years
nCounter Dx license
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 46,880	46,880
Accumulated Amortization	(3,386)	(263)
Net Carrying Amount	$ 43,494	46,617
Weighted Average Amortization Period (Years)	15 years
LymphMark product technology
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 990	990
Accumulated Amortization	(153)	(12)
Net Carrying Amount	$ 837	$ 978
Weighted Average Amortization Period (Years)	7 years

Balance Sheet Components - Addi

Balance Sheet Components - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Balance Sheet Related Disclosures [Abstract]
Intangible asset amortization	$ 5,095	$ 1,401	$ 1,067

Balance Sheet Components - Futu

Balance Sheet Components - Future Amortization (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Balance Sheet Related Disclosures [Abstract]
2021	$ 5,094
2022	5,094
2023	5,094
2024	5,054
2025	4,608
Thereafter	34,980
Net Carrying Amount	$ 59,924	$ 65,019

Balance Sheet Components - Accr

Balance Sheet Components - Accrued Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Accrued Liabilities
Accrued compensation expense	$ 9,201	$ 10,100
Accrued other	2,504	3,634
Total accrued liabilities	$ 11,705	$ 13,734

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Headquarters and laboratory facilities, South San Francisco, Lease signed in April 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Security deposit	$ 603	$ 603
Money Market Funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	346,800	57,600
Overnight Reverse Repurchase Agreements
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Unrealized gain (loss) from overnight reverse repurchase agreements	0	0
Fair Value, Inputs, Level 2 \| Overnight Repurchase Agreements
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	$ 0	$ 100,000

Fair Value Measurements - Fair

Fair Value Measurements - Fair Value Measurement Input (Details)	Dec. 31, 2020
Discount rate
Measurement input	0.069
Probability of achievement \| Minimum
Measurement input	0.70
Probability of achievement \| Maximum
Measurement input	1
Probability of achievement \| Weighted Average
Measurement input	0.86

Commitments and Contingencies_2

Commitments and Contingencies (Details) ft² in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2020USD ($)ft²	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)
Operating Leases
Discount rate	7.53%
Facilities rent expense	$ 1,900	$ 1,900	$ 1,900
Purchase obligation	4,800
Future minimum lease payments under non-cancelable operating leases
2021	2,401
2022	2,472
2023	2,543
2024	2,614
2025	2,685
Thereafter	1,542
Total future minimum lease payments	14,257
Less: amount representing interest	2,751
Present value of future lease payments	11,506
Less: short-term lease liabilities	1,589	1,407
Long-term lease liabilities	$ 9,917	11,506
Headquarters and laboratory facilities, South San Francisco, Lease signed in April 2015
Operating Leases
Amount of space leased (in square feet) \| ft²	59
Security deposit	$ 603	603
Laboratory facilities, Austin, Texas
Operating Leases
Security deposit	$ 139	$ 139

Debt - Loan and Security Agreem

Debt - Loan and Security Agreement (Details) - USD ($)	Nov. 03, 2017	Aug. 31, 2020	May 31, 2019	Jan. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Line of Credit Facility [Line Items]
Repayments of long-term debt					$ 100,000	$ 24,900,000	$ 0
Line of credit \| Silicon Valley Bank
Line of Credit Facility [Line Items]
Line of credit facility, maximum borrowing capacity	$ 35,000,000
Long-term debt balance outstanding					810,000	$ 694,000
Future principal and debt obligation					$ 1,200,000
Line of credit \| Silicon Valley Bank \| Secured Debt
Line of Credit Facility [Line Items]
Line of credit facility, maximum borrowing capacity	25,000,000
Periodic payment terms, balloon payment to be paid	1,200,000
Line of credit \| Silicon Valley Bank \| Revolving credit facility
Line of Credit Facility [Line Items]
Line of credit facility, maximum borrowing capacity	$ 10,000,000
Effective interest rate					5.40%
Repayments of long-term debt		$ 100,000	$ 12,400,000	$ 12,500,000
Term Loan Advance \| Silicon Valley Bank
Line of Credit Facility [Line Items]
Long-term debt balance outstanding					$ 1
LIBOR \| Line of credit \| Silicon Valley Bank \| Secured Debt
Line of Credit Facility [Line Items]
Basis spread on variable rate	4.20%
LIBOR \| Line of credit \| Silicon Valley Bank \| Revolving credit facility
Line of Credit Facility [Line Items]
Basis spread on variable rate	3.50%
Minimum \| LIBOR \| Line of credit \| Silicon Valley Bank \| Secured Debt
Line of Credit Facility [Line Items]
Interest rate, stated percentage	5.43%
Minimum \| LIBOR \| Line of credit \| Silicon Valley Bank \| Revolving credit facility
Line of Credit Facility [Line Items]
Interest rate, stated percentage	4.70%
Debt prepayment tranche three \| LIBOR \| Line of credit \| Silicon Valley Bank \| Revolving credit facility
Line of Credit Facility [Line Items]
Prepayment premium	$ 250,000

Debt - Schedule of Loan and Sec

Debt - Schedule of Loan and Security Agreement (Details) - Line of credit - Silicon Valley Bank - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Debt principal	$ 0	$ 100
End-of-term debt obligation	810	594
Net debt obligation	$ 810	$ 694

Debt - Interest Expense (Detail

Debt - Interest Expense (Details) - USD ($) $ in Thousands	12 Months Ended
Debt - Interest Expense (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Debt Disclosure [Abstract]
Nominal debt interest	$ 13	$ 332	$ 1,568
Amortization and write-off of debt discount and issuance costs	0	107	57
End-of-term debt obligation interest	216	229	312
Interest on capital lease	0	9	26
Total	$ 229	$ 677	$ 1,963

Stockholders' Equity (Details)

Stockholders' Equity (Details)	1 Months Ended			12 Months Ended
Stockholders' Equity (Details)	Aug. 31, 2020USD ($)$ / sharesshares	May 31, 2019USD ($)$ / sharesshares	Jul. 31, 2018USD ($)$ / sharesshares	Dec. 31, 2020USD ($)vote$ / sharesshares	Dec. 31, 2019$ / sharesshares
Common Stock
Common stock, shares authorized (in shares)				125,000,000	125,000,000
Par value of shares of common stock (in USD per share) \| $ / shares				$ 0.001	$ 0.001
Number of votes for each share of stock (in votes) \| vote				1
Dividends declared \| $				$ 0
Options issued and outstanding (in shares)				4,867,303	5,562,484
Total number of shares reserved for issuance (in shares)				9,500,287	7,690,456
Number of shares issued in transaction (in shares)	6,900,000	6,325,000	5,750,000
Proceeds from issuance of common stock \| $	$ 193,800,000	$ 137,800,000	$ 55,000,000
Payments of stock issuance costs \| $	$ 13,200,000	$ 9,200,000	$ 3,900,000
Over-Allotment Option
Common Stock
Number of shares issued in transaction (in shares)	900,000	825,000	750,000
Shares of common stock subject to outstanding options
Common Stock
Options issued and outstanding (in shares)				4,867,303	5,562,484
Shares available for issuance (in shares)				3,061,589	1,954,804
Employee stock purchase plan
Common Stock
Shares available for issuance (in shares)				1,571,395	173,168
Total number of shares reserved for issuance (in shares)				1,571,395
Common Stock
Common Stock
Shares issued, price per share (in USD per share) \| $ / shares	$ 30	$ 23.25	$ 10.25

Stock Incentive Plans - Stock O

Stock Incentive Plans - Stock Option Plans (Details) - shares	1 Months Ended	12 Months Ended
	Feb. 29, 2008	Dec. 31, 2020	Oct. 31, 2013
2008 Plan \| ISO \| Minimum
Stock incentive plans
Voting power of person owning stock	10.00%
Option price as a percentage of estimated fair value of shares to person owning more than 10% of voting power stock	110.00%
2008 Plan \| ISO \| Maximum
Stock incentive plans
Term of options to person owning more than 10% of voting power stock	5 years
2008 Plan \| Employee stock options \| Minimum
Stock incentive plans
Minimum purchase price as a percentage of fair market value	100.00%
2008 Plan \| Employee stock options \| Maximum
Stock incentive plans
Term of options granted	10 years
2013 Plan
Stock incentive plans
Number of additional shares reserved for issuance (in shares)			1,700,000
Maximum annual increase as a percentage in outstanding shares on the last day of the preceding fiscal year		4.00%
Number of shares available for issuance (in shares)		3,061,589
2013 Plan \| ISO \| Maximum
Stock incentive plans
Minimum purchase price as a percentage of fair market value		100.00%
2013 Plan \| NSO \| Outside director who was not previously an employee
Stock incentive plans
Shares granted as initial grant (in shares)		35,000
2013 Plan \| Employee stock options \| Outside director serving as a member of Board of Directors for at least six months
Stock incentive plans
Shares granted as annual grant (in shares)		10,000
2013 Plan \| Employee stock options \| Outside director serving as a member of Board of Directors for at least six months \| Minimum
Stock incentive plans
Period director must serve as board of director to receive grant to purchase shares		6 months
2013 Plan \| Employee stock options \| Outside director
Stock incentive plans
Minimum purchase price as a percentage of fair market value		100.00%
2013 Plan \| Employee stock options \| Outside director \| Maximum
Stock incentive plans
Expiration period after termination of service		12 months

Stock Incentive Plans - Activit

Stock Incentive Plans - Activity Under Stock Option Plans (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Shares Available for Grant
Additional shares authorized (in shares)	1,985,013
Canceled (in shares)	421,558
Stock Options Outstanding and Unvested Stock Units
Balance at beginning of the period (in shares)	5,562,484
Canceled (in shares)	(421,558)
Exercised (in shares)	(1,345,134)
Balance at the end of the period (in shares)	4,867,303	5,562,484
Options vested and exercisable at the end of the period (in shares)	2,316,166
Options vested and expected to vest at the end of the period (in shares)	3,858,859
Weighted Average Exercise Price of Stock Options
Balance at beginning of the period (in dollars per share)	$ 10.66
Canceled (in USD per share)	6.51
Exercised (in USD per share)	8.67
Balance at the end of the period (in dollars per share)	15.14	$ 10.66
Options vested and exercisable at the end of the period (in USD per share)	10.35
Options vested and expected to vest at the end of the period (in USD per share)	$ 14.78
Weighted Average Remaining Contractual Life of Stock Options (Years)
Remaining contractual life of stock options at beginning and end of period	6 years 11 months 23 days	6 years 11 months 19 days
Options vested and exercisable at the end of the period (in years)	5 years 9 months 10 days
Options vested and expected to vest at the end of the period (in years)	6 years 10 months 28 days
Aggregate Intrinsic Value of Stock Options
Balance at beginning of period	$ 79,760
Balance at end of period	135,879	$ 79,760
Options vested and exercisable at the end of the period	89,376
Options vested and expected to vest at the end of the period	$ 131,816
Employee stock options
Shares Available for Grant
Granted (in shares)	(983,900)
Stock Options Outstanding and Unvested Stock Units
Granted (in shares)	983,900
Weighted Average Exercise Price of Stock Options
Granted (in USD per share)	$ 26.40
Restricted stock units
Shares Available for Grant
Granted (in shares)	(451,709)
Tax portion of restricted stock units vested (in shares)	135,823
Stock Options Outstanding and Unvested Stock Units
Granted (in shares)	451,709
Vested (in shares)	(364,098)
Aggregate Intrinsic Value of Stock Options
Options vested and expected to vest at the end of the period	$ 10,300	$ 2,700
Shares of common stock subject to outstanding options
Shares Available for Grant
Balance at the beginning of the period (in shares)	1,954,804
Balance at the end of the period (in shares)	3,061,589	1,954,804
Stock Options Outstanding and Unvested Stock Units
Balance at beginning of the period (in shares)	5,562,484
Balance at the end of the period (in shares)	4,867,303	5,562,484

Stock Incentive Plans - Additio

Stock Incentive Plans - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Stock incentive plans
Weighted average fair value of options to purchase common stock granted (in USD per share)	$ 12.97	$ 11.07	$ 3.62
Intrinsic value of stock options exercised	$ 32,900	$ 31,300	$ 4,900
Weighted average grant date fair value (in USD per share)	$ 27.09	$ 21.90
Intrinsic value of stock options outstanding	$ 131,816
Options outstanding (in shares)	4,867,303	5,562,484
Common Stock
Stock incentive plans
Share price (in USD per share)	$ 48.94	$ 27.92
Employee stock options
Stock incentive plans
Estimated grant date fair value of options to purchase common stock vested	$ 7,300	$ 4,400	$ 4,100
Restricted stock units
Stock incentive plans
Intrinsic value of stock options outstanding	$ 10,300	$ 2,700
Non Employee Stock Option
Stock incentive plans
Options outstanding (in shares)	0

Stock Incentive Plans - ESPP (D

Stock Incentive Plans - ESPP (Details) - USD ($)	12 Months Ended
Stock Incentive Plans - ESPP (Details) - USD ($)	Dec. 31, 2020	Dec. 31, 2019
Stock incentive plans
Shares of common stock reserved for issuance under ESPP	9,500,287	7,690,456
Employee stock purchase plan
Stock incentive plans
Maximum offering period	12 months
Purchase period	6 months
Maximum fair market value of shares available to purchase per calendar year	$ 25,000
Shares of common stock reserved for issuance under ESPP	1,571,395
Employee stock purchase plan \| Minimum
Stock incentive plans
Minimum purchase price as a percentage of fair market value	85.00%

Stock Incentive Plans - Stock-b

Stock Incentive Plans - Stock-based Compensation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Stock-based compensation
Share-based compensation expense	$ 12,995	$ 9,807	$ 5,958
Cost of testing revenue
Stock-based compensation
Share-based compensation expense	369	277	130
Research and development
Stock-based compensation
Share-based compensation expense	2,690	1,856	1,018
Selling and marketing
Stock-based compensation
Share-based compensation expense	3,474	2,938	1,866
General and administrative
Stock-based compensation
Share-based compensation expense	6,462	$ 4,736	$ 2,944
Stock-based Compensation
Stock-based compensation
Unrecognized compensation expense	$ 25,700
Period over which unrecognized compensation expense expected to be recognized	2 years 4 months 24 days
Stock-based Compensation, employees
Stock-based compensation
Expected dividend yield	0.00%	0.00%	0.00%
Assumptions used to calculate estimated fair value of stock options using the Black-Scholes option-pricing valuation model
Weighted-average minimum volatility (as a percent)	54.40%	52.90%	50.40%
Weighted-average maximum volatility (as a percent)	58.20%	53.40%	52.70%
Risk-free minimum interest rate (as a percent)	0.24%	1.90%	2.40%
Risk-free maximum interest rate (as a percent)	0.92%	2.60%	3.10%
Expected dividend yield	0.00%	0.00%	0.00%
Stock-based Compensation, non-employees
Stock-based compensation
Expected dividend yield	0.00%	0.00%	0.00%
Assumptions used to calculate estimated fair value of stock options using the Black-Scholes option-pricing valuation model
Weighted-average minimum volatility (as a percent)			43.60%
Weighted-average maximum volatility (as a percent)			50.50%
Weighted-average volatility	0.00%	0.00%
Risk-free minimum interest rate (as a percent)			1.84%
Risk-free maximum interest rate (as a percent)			2.87%
Risk-free interest rate	0.00%	0.00%
Expected dividend yield	0.00%	0.00%	0.00%
Employee stock purchase plan
Stock-based compensation
Expected dividend yield	0.00%	0.00%	0.00%
Assumptions used to calculate estimated fair value of stock options using the Black-Scholes option-pricing valuation model
Weighted-average minimum volatility (as a percent)	54.16%	53.38%	42.88%
Weighted-average maximum volatility (as a percent)	85.01%	71.77%	47.74%
Risk-free minimum interest rate (as a percent)	0.11%	1.88%	1.64%
Risk-free maximum interest rate (as a percent)	1.56%	2.56%	2.45%
Expected dividend yield	0.00%	0.00%	0.00%
Minimum \| Stock-based Compensation, employees
Assumptions used to calculate estimated fair value of stock options using the Black-Scholes option-pricing valuation model
Weighted-average expected term (in years)	5 years 2 months 26 days	5 years 6 months	5 years 6 months
Minimum \| Stock-based Compensation, non-employees
Assumptions used to calculate estimated fair value of stock options using the Black-Scholes option-pricing valuation model
Weighted-average expected term (in years)			3 months
Minimum \| Employee stock purchase plan
Assumptions used to calculate estimated fair value of stock options using the Black-Scholes option-pricing valuation model
Weighted-average expected term (in years)	6 months	6 months	6 months
Maximum \| Stock-based Compensation, employees
Assumptions used to calculate estimated fair value of stock options using the Black-Scholes option-pricing valuation model
Weighted-average expected term (in years)	5 years 5 months 1 day	6 years 29 days	6 years 29 days
Maximum \| Stock-based Compensation, non-employees
Assumptions used to calculate estimated fair value of stock options using the Black-Scholes option-pricing valuation model
Weighted-average expected term (in years)			6 years 9 months
Maximum \| Employee stock purchase plan
Assumptions used to calculate estimated fair value of stock options using the Black-Scholes option-pricing valuation model
Weighted-average expected term (in years)	1 year	1 year	1 year

Thyroid Cytopathology Partners

Thyroid Cytopathology Partners (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Thyroid Cytopathology Partners
Thyroid Cytopathology Partners
Sublease income	$ 11	$ 128

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details) - USD ($)	12 Months Ended
Income Taxes - Additional Information (Details) - USD ($)	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Pretax loss	$ 34,800,000	$ 12,500,000	$ 23,000,000
Income tax expense (benefit)	0	0	0
Valuation allowance against deferred tax assets	13,400,000	9,900,000	3,700,000
Operating loss carryforwards
Unrecognized tax benefits	3,563,000	$ 3,278,000	$ 2,799,000	$ 2,523,000
Federal
Operating loss carryforwards
Net operating loss carryforwards	282,900,000
Tax credit carryforward	5,300,000
State
Operating loss carryforwards
Tax credit carryforward	5,200,000
State \| California
Operating loss carryforwards
Net operating loss carryforwards	63,000,000
State \| Other state income tax purposes
Operating loss carryforwards
Net operating loss carryforwards	$ 72,200,000

Income Taxes - Tax Provision (D

Income Taxes - Tax Provision (Details) - USD ($)	12 Months Ended
Income Taxes - Tax Provision (Details) - USD ($)	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Reconciliation of tax expense computed at the statutory federal rate and the Company's tax expense
U.S. federal taxes at statutory rate	$ (7,302,000)	$ (2,632,000)	$ (4,825,000)
State tax (net of federal benefit)	(1,794,000)	(828,000)	0
Foreign rate differential	1,000	0	0
Non deductible officers' compensation	1,443,000	439,000	409,000
Permanent differences	131,000	221,000	285,000
Stock based compensation including excess tax benefit	(4,881,000)	(4,366,000)	(256,000)
Tax credits	(588,000)	(996,000)	(777,000)
Change in valuation allowance	12,990,000	8,162,000	5,164,000
Total	$ 0	$ 0	$ 0

Income Taxes - Deferred Tax Ass

Income Taxes - Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Deferred tax assets:
Net operating loss carryforwards	$ 68,113	$ 56,506	$ 50,410
Research and development credits	6,167	5,579	4,584
Stock-based compensation	2,696	2,246	1,032
NanoString intangibles and goodwill	908	380	0
Operating lease liability	2,826	3,068	0
Accruals and other	2,623	2,610	2,918
Gross deferred tax assets	83,333	70,389	58,944
Valuation allowance	(78,650)	(65,228)	(55,366)
Net deferred tax assets	4,683	5,161	3,578
Deferred tax liabilities:
Property and equipment	(334)	(471)	(695)
In-process research and development	(2,423)	(2,597)	(2,883)
ROU assets	(1,926)	(2,093)	0
Gross deferred tax liabilities	(4,683)	(5,161)	(3,578)
Net deferred tax liabilities	(4,683)	(5,161)	(3,578)
Net deferred taxes	$ 0	$ 0	$ 0

Income Taxes - Uncertain Tax Po

Income Taxes - Uncertain Tax Positions (Details) - USD ($)	12 Months Ended
Income Taxes - Uncertain Tax Positions (Details) - USD ($)	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Reconciliation of the beginning and ending amount of unrecognized tax benefits
Unrecognized tax benefits, beginning of period	$ 3,278,000	$ 2,799,000	$ 2,523,000
Gross increases—tax position in prior period	0	0	0
Gross decreases—tax position in prior period	0	0	(97,000)
Gross increases—current period tax position	285,000	479,000	373,000
Lapse of statute of limitations	0	0	0
Unrecognized tax benefits, end of period	3,563,000	$ 3,278,000	$ 2,799,000
Interest expense or penalties related to unrecognized tax benefits	$ 0

Income Taxes - Income Tax Exami

Income Taxes - Income Tax Examination (Details)	12 Months Ended
Income Taxes - Income Tax Examination (Details)	Dec. 31, 2020
Federal
Income tax examination
Income tax examination period	3 years
State
Income tax examination
Income tax examination period	4 years

401(k) Plan (Details)

401(k) Plan (Details) - USD ($) $ in Thousands	12 Months Ended
401(k) Plan (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Retirement Benefits [Abstract]
Employer contributions to the plan	$ 613	$ 509	$ 448

Selected Quarterly Financial _3

Selected Quarterly Financial Data (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Selected Quarterly Financial Data (Unaudited)
Total revenue	$ 34,536	$ 31,121	$ 20,704	$ 31,122	$ 29,730	$ 30,973	$ 30,136	$ 29,529	$ 117,483	$ 120,368	$ 92,008
Net loss	$ (8,044)	$ (4,124)	$ (11,025)	$ (11,716)	$ (7,458)	$ (730)	$ (2,494)	$ (1,917)	$ (34,909)	$ (12,599)	$ (22,999)
Net loss per common share, basic and diluted (in USD per share)	$ (0.14)	$ (0.08)	$ (0.22)	$ (0.24)	$ (0.15)	$ (0.02)	$ (0.05)	$ (0.05)	$ (0.66)	$ (0.27)	$ (0.62)
Shares use to compute net loss per common share, basic and diluted (in shares)	58,023,753	54,858,052	50,212,123	49,792,631	49,095,703	48,588,296	45,586,081	41,168,593	53,239,231	46,138,177	37,020,246

Subsequent Events (Details)

Subsequent Events (Details) - USD ($) $ / shares in Units, $ in Thousands	Feb. 09, 2021	Feb. 22, 2021	Aug. 31, 2020	May 31, 2019	Jul. 31, 2018	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Subsequent Event [Line Items]
Cash paid for acquisition						$ 0	$ 40,000	$ 0
Number of shares issued in transaction (in shares)			6,900,000	6,325,000	5,750,000
Proceeds from issuance of common stock			$ 193,800	$ 137,800	$ 55,000
Payments of stock issuance costs			$ 13,200	$ 9,200	$ 3,900
Common Stock
Subsequent Event [Line Items]
Shares issued, price per share (in USD per share)			$ 30	$ 23.25	$ 10.25
Over-Allotment Option
Subsequent Event [Line Items]
Number of shares issued in transaction (in shares)			900,000	825,000	750,000
Subsequent Event
Subsequent Event [Line Items]
Number of shares issued in transaction (in shares)	8,547,297
Proceeds from issuance of common stock	$ 593,800
Payments of stock issuance costs	$ 38,700
Subsequent Event \| Common Stock
Subsequent Event [Line Items]
Shares issued, price per share (in USD per share)	$ 74
Subsequent Event \| Over-Allotment Option
Subsequent Event [Line Items]
Number of shares issued in transaction (in shares)	1,114,864
Decipher Biosciences \| Subsequent Event
Subsequent Event [Line Items]
Cash paid for acquisition		$ 600,000