CareDx (CDNA) 10-Q 1 Aug 19 2019 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2019	Jul. 30, 2019
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2019
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q2
Trading Symbol	CDNA
Entity Registrant Name	CareDx, Inc.
Entity Central Index Key	0001217234
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Ex Transition Period	true
Entity Shell Company	false
Entity Address, State or Province	California
Entity Address, Country	US
Entity Common Stock, Shares Outstanding		42,383,761
Entity File Number	001-36536
Entity Tax Identification Number	943316839
Entity Address, Address Line One	3260 Bayshore Boulevard
Entity Address, City or Town	Brisbane
Entity Address, Postal Zip Code	94005
City Area Code	415
Local Phone Number	287-2300
Entity Current Reporting Status	Yes

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 43,469	$ 64,616
Accounts receivable	17,052	9,760
Inventory	5,341	4,943
Prepaid and other current assets	2,462	1,795
Total current assets	68,324	81,114
Property and equipment, net	3,508	4,134
Operating leases right-of-use assets	2,657	0
Intangible assets, net	45,604	33,252
Goodwill	22,559	12,005
Restricted cash	255	192
Total assets	142,907	130,697
Current liabilities:
Accounts payable	7,380	4,711
Accrued compensation	7,490	9,156
Accrued and other liabilities	13,750	5,637
Total current liabilities	28,620	19,504
Deferred tax liability	2,310	2,968
Common stock warrant liability	11,286	10,003
Deferred payments for intangible assets	4,930	0
Other liabilities	2,595	2,294
Total liabilities	49,741	34,769
Commitments and contingencies (Note 8)	0	0
Stockholders’ equity:
Preferred stock: $0.001 par value; 10,000,000 shares authorized at June 30, 2019 and December 31, 2018; no shares issued and outstanding at June 30, 2019 and December 31, 2018	0	0
Common stock: $0.001 par value; 100,000,000 shares authorized at June 30, 2019 and December 31, 2018; 42,306,432 shares and 41,384,960 shares issued and outstanding at June 30, 2019 and December 31, 2018, respectively	42	41
Additional paid-in capital	425,418	412,010
Accumulated other comprehensive loss	(5,071)	(4,278)
Accumulated deficit	(327,223)	(311,845)
Total stockholders' equity	93,166	95,928
Total liabilities and stockholders’ equity	$ 142,907	$ 130,697

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Jun. 30, 2019	Dec. 31, 2018
Statement Of Financial Position [Abstract]
Preferred stock, par value	$ 0.001	$ 0.001
Preferred stock, shares authorized	10,000,000	10,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.001	$ 0.001
Common stock, shares authorized	100,000,000	100,000,000
Common stock, shares issued	42,306,432	41,384,960
Common stock, shares outstanding	42,306,432	41,384,960

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operation - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Revenue:
Total revenue	$ 31,454	$ 17,823	$ 57,436	$ 31,876
Cost of revenue	11,512	7,207	21,245	13,591
Gross profit	19,942	10,616	36,191	18,285
Operating expenses:
Research and development	7,630	3,496	13,244	6,864
Sales and marketing	10,644	5,860	17,569	9,945
General and administrative	8,512	5,596	17,618	10,903
Change in estimated fair value of contingent consideration	0	873	0	1,017
Total operating expenses	26,786	15,825	48,431	28,729
Loss from operations	(6,844)	(5,209)	(12,240)	(10,444)
Other income (expense):
Interest income (expense), net	300	(424)	642	(3,119)
Debt extinguishment expenses	0	0	0	(2,806)
Change in estimated fair value of common stock warrant liability and derivative liability	(1,351)	(8,768)	(4,360)	(7,447)
Other expense, net	(172)	(42)	(246)	(45)
Total other income (expense)	(1,223)	(9,234)	(3,964)	(13,417)
Loss before income taxes	(8,067)	(14,443)	(16,204)	(23,861)
Income tax benefit	220	381	826	805
Net loss	(7,847)	(14,062)	(15,378)	(23,056)
Net loss attributable to noncontrolling interest	0	0	0	(25)
Net loss attributable to CareDx, Inc.	$ (7,847)	$ (14,062)	$ (15,378)	$ (23,031)
Net loss per share attributable to CareDx, Inc. (Note 3):
Basic	$ (0.19)	$ (0.40)	$ (0.37)	$ (0.71)
Diluted	$ (0.19)	$ (0.40)	$ (0.37)	$ (0.71)
Weighted-average shares used to compute net loss per share attributable to CareDx, Inc.:
Basic	42,132,396	35,549,837	41,873,337	32,599,032
Diluted	42,132,396	35,549,837	41,873,337	32,599,032
Testing Services [Member]
Revenue:
Total revenue	$ 25,677	$ 13,997	$ 47,195	$ 24,601
Product [Member]
Revenue:
Total revenue	4,593	3,550	9,026	6,857
Digital and Other [Member]
Revenue:
Total revenue	$ 1,184	$ 276	$ 1,215	$ 418

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Statement Of Income And Comprehensive Income [Abstract]
Net loss	$ (7,847)	$ (14,062)	$ (15,378)	$ (23,056)
Other comprehensive loss:
Foreign currency translation adjustments, net of tax	(69)	(1,625)	(793)	(1,762)
Net comprehensive loss	(7,916)	(15,687)	(16,171)	(24,818)
Comprehensive loss attributable to noncontrolling interest, net of tax	0	0	0	(25)
Comprehensive loss attributable to CareDx, Inc.	$ (7,916)	$ (15,687)	$ (16,171)	$ (24,793)

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Stockholders' Equity (Unaudited) - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Other Comprehensive Loss [Member]	Accumulated Deficit [Member]	Noncontrolling Interest [Member]
Beginning Balance at Dec. 31, 2017	$ (5,955)	$ 29	$ 264,204	$ (2,346)	$ (268,022)	$ 180
Beginning Balance, Shares at Dec. 31, 2017		28,825,019
Adoption of ASC 606 | ASU 2014-09 [Member]	2,933	$ 0	0	0	2,933	0
Reclassification of warrants from liability to equity	6,550	0	6,550	0	0	0
Conversion of convertible debt	38,854	$ 6	38,848	0	0	0
Conversion of convertible debt, Shares		6,161,331
Issuance of common stock under ESPP	32	$ 0	32	0	0	0
Issuance of common stock under ESPP shares		34,176
RSU settlements, net of shares withheld	(128)	$ 0	(128)	0	0	0
RSU settlements, net of shares withheld shares		49,330
Issuance of common stock for services	62	$ 0	62	0	0	0
Issuance of common stock for services, Shares		5,772
Issuance of common stock for cash upon exercise of stock options	80	$ 0	80	0	0	0
Issuance of common stock for cash upon exercise of stock options, Shares		142,554
Issuance of common stock for cash upon exercise of warrants	153	$ 0	153	0	0	0
Issuance of common stock for cash upon exercise of warrants, Shares		22,600
Share-based compensation expense	634	$ 0	634	0	0	0
Noncontrolling interests upon acquisition	(692)	0	(537)	0	0	(155)
Foreign currency translation adjustment	(137)	0	0	(137)	0	0
Net loss	(8,994)	0	0	0	(8,969)	(25)
Ending Balance at Mar. 31, 2018	33,392	$ 35	309,898	(2,483)	(274,058)	0
Ending Balance, Shares at Mar. 31, 2018		35,240,782
Beginning Balance at Dec. 31, 2017	(5,955)	$ 29	264,204	(2,346)	(268,022)	180
Beginning Balance, Shares at Dec. 31, 2017		28,825,019
Foreign currency translation adjustment	(1,762)
Net loss	(23,056)
Ending Balance at Jun. 30, 2018	28,952	$ 36	321,144	(4,108)	(288,120)	0
Ending Balance, Shares at Jun. 30, 2018		35,975,593
Beginning Balance at Dec. 31, 2017	(5,955)	$ 29	264,204	(2,346)	(268,022)	180
Beginning Balance, Shares at Dec. 31, 2017		28,825,019
Ending Balance at Dec. 31, 2018	95,928	$ 41	412,010	(4,278)	(311,845)
Ending Balance, Shares at Dec. 31, 2018		41,384,960
Beginning Balance at Mar. 31, 2018	33,392	$ 35	309,898	(2,483)	(274,058)	0
Beginning Balance, Shares at Mar. 31, 2018		35,240,782
RSU settlements, net of shares withheld	(570)	$ 0	(570)	0	0	0
RSU settlements, net of shares withheld shares		24,306
Issuance of common stock for services	72	$ 0	72	0	0	0
Issuance of common stock for services, Shares		12,147
Issuance of common stock for cash upon exercise of stock options	98	$ 0	98	0	0	0
Issuance of common stock for cash upon exercise of stock options, Shares		24,934
Issuance of common stock for cash upon exercise of warrants	5,724	$ 0	5,724	0	0	0
Issuance of common stock for cash upon exercise of warrants, Shares		445,576
Share-based compensation expense	2,449	$ 0	2,449	0	0	0
Issuance of common stock for contingent consideration	2,690	$ 1	2,689	0	0	0
Issuance of common stock for contingent consideration, shares		227,848
Issuance of warrants in connection with Perceptive debt	784	$ 0	784	0	0	0
Foreign currency translation adjustment	(1,625)	0	0	(1,625)	0	0
Net loss	(14,062)	0	0	0	(14,062)	0
Ending Balance at Jun. 30, 2018	28,952	$ 36	321,144	(4,108)	(288,120)	$ 0
Ending Balance, Shares at Jun. 30, 2018		35,975,593
Beginning Balance at Dec. 31, 2018	95,928	$ 41	412,010	(4,278)	(311,845)
Beginning Balance, Shares at Dec. 31, 2018		41,384,960
Issuance of common stock under ESPP	341	$ 0	341	0	0
Issuance of common stock under ESPP shares		31,184
RSU settlements, net of shares withheld	(2,378)	$ 0	(2,378)	0	0
RSU settlements, net of shares withheld shares		146,159
Issuance of common stock for services	51	$ 0	51	0	0
Issuance of common stock for services, Shares		2,112
Issuance of common stock for cash upon exercise of stock options	1,365	$ 0	1,365	0	0
Issuance of common stock for cash upon exercise of stock options, Shares		253,347
Issuance of common stock for cash upon exercise of warrants	2,569	$ 0	2,569	0	0
Issuance of common stock for cash upon exercise of warrants, Shares		94,707
Share-based compensation expense	6,001	$ 0	6,001	0	0
Foreign currency translation adjustment	(724)	0	0	(724)	0
Net loss	(7,531)	0	0	0	(7,531)
Ending Balance at Mar. 31, 2019	95,622	$ 41	419,959	(5,002)	(319,376)
Ending Balance, Shares at Mar. 31, 2019		41,912,469
Beginning Balance at Dec. 31, 2018	$ 95,928	$ 41	412,010	(4,278)	(311,845)
Beginning Balance, Shares at Dec. 31, 2018		41,384,960
Issuance of common stock for cash upon exercise of stock options, Shares	491,581
Foreign currency translation adjustment	$ (793)
Net loss	(15,378)
Ending Balance at Jun. 30, 2019	93,166	$ 42	425,418	(5,071)	(327,223)
Ending Balance, Shares at Jun. 30, 2019		42,306,432
Beginning Balance at Mar. 31, 2019	95,622	$ 41	419,959	(5,002)	(319,376)
Beginning Balance, Shares at Mar. 31, 2019		41,912,469
Changes in estimated offering costs	50	$ 0	50	0	0
RSU settlements, net of shares withheld	(1,597)	$ 0	(1,597)	0	0
RSU settlements, net of shares withheld shares		112,760
Issuance of common stock for services	52	$ 0	52	0	0
Issuance of common stock for services, Shares		1,663
Issuance of common stock for cash upon exercise of stock options	1,405	$ 1	1,404	0	0
Issuance of common stock for cash upon exercise of stock options, Shares		240,734
Issuance of common stock for cash upon exercise of warrants	612	$ 0	612	0	0
Issuance of common stock for cash upon exercise of warrants, Shares		38,806
Share-based compensation expense	4,938	$ 0	4,938	0	0
Foreign currency translation adjustment	(69)	0	0	(69)	0
Net loss	(7,847)	0	0	0	(7,847)
Ending Balance at Jun. 30, 2019	$ 93,166	$ 42	$ 425,418	$ (5,071)	$ (327,223)
Ending Balance, Shares at Jun. 30, 2019		42,306,432

Condensed Consolidated Statem_4

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Operating activities:
Net loss	$ (15,378)	$ (23,056)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation	11,045	3,217
Revaluation of common stock warrant liability and derivative liability to estimated fair value	4,360	7,447
Depreciation and amortization	2,380	2,025
Loss on the write-off of fixed assets	150	0
Non-cash lease expense	201	0
Amortization of inventory fair market value adjustment	0	189
Loss on conversion of JGB Debt to shares of common stock	0	2,806
Amortization of debt discount and noncash interest expense	0	2,132
Revaluation of contingent consideration to estimated fair value	0	1,017
Changes in operating assets and liabilities:
Accounts receivable	(5,956)	(2,280)
Inventory	(551)	333
Prepaid and other assets	(219)	(296)
Operating leases liabilities	(418)	0
Accounts payable	3,285	195
Accrued compensation	(1,881)	686
Accrued and other liabilities	1,208	73
Change in deferred taxes	(517)	(892)
Net cash used in operating activities	(2,291)	(6,404)
Investing activities:
Acquisition of business	(16,037)	0
Acquisition of intangible assets	(1,124)	(5,202)
Acquisition of noncontrolling interests, net of cash acquired	0	(692)
Purchase of property and equipment, net	(561)	(461)
Net cash used in investing activities	(17,722)	(6,355)
Financing activities:
Proceeds from Perceptive term loan, net of issuance costs	0	14,282
Proceeds from issuance of common stock under employee stock purchase plan	341	32
Taxes paid related to net share settlement of restricted stock units	(3,975)	(142)
Proceeds from exercise of warrants	105	524
Proceeds from exercise of stock options	2,769	179
Principal payments on debt and finance lease obligations	(84)	(11,349)
Change in short term credit facility	0	(677)
Net cash (used in) provided by financing activities	(960)	2,758
Effect of exchange rate changes on cash and cash equivalents	(111)	(50)
Net decrease in cash, cash equivalents and restricted cash	(21,084)	(10,051)
Cash, cash equivalents, and restricted cash at beginning of period	64,808	26,474
Cash, cash equivalents, and restricted cash at end of period	43,724	16,423
Supplemental disclosure of cash flow information:
Deferred payments for intangible assets	6,954	0
Operating leases right-of-use assets	2,657	0
Accrued purchase consideration	111	0
Conexio [Member]
Financing activities:
Contingent payments related to the acquisition of Conexio Genomics Pty Ltd.	$ (116)	$ (91)

Condensed Consolidated Statem_5

Condensed Consolidated Statements of Cash Flows (Parenthetical) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018	Jun. 30, 2018	Dec. 31, 2017
Cash, Cash Equivalents and Restricted Cash as of:
Cash and cash equivalents	$ 43,469	$ 64,616
Restricted cash	255	192
Total cash, cash equivalents and restricted cash at the end of period	$ 43,724	$ 64,808	$ 16,423	$ 26,474

Organization and Description of

Organization and Description of Business	6 Months Ended
	Jun. 30, 2019
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Organization and Description of Business	1. ORGANIZATION AND DESCRIPTION OF BUSINESS CareDx, Inc. (“CareDx” or the “Company”) together with its subsidiaries, is a leading precision medicine company focused on the discovery, development and commercialization of clinically differentiated, high-value healthcare solutions for transplant patients and caregivers. The Company’s headquarters are in Brisbane, California. The primary operations are in Brisbane, California; Omaha, Nebraska; Fremantle, Australia and Stockholm, Sweden. The Company’s commercially available testing services consist of AlloMap® Heart, which is a gene expression solution for heart transplant patients, and AlloSure® Kidney, which is a donor-derived cell-free DNA (“dd-cfDNA”) solution for kidney transplant patients. The Company also offers high quality products that increase the chance of successful transplants by facilitating a better match between a donor and a recipient of stem cells and organs. On May 7, 2019, the Company completed the acquisition of 100% of the outstanding equity of OTTR Complete Transplant Management (“OTTR”). OTTR’s solutions enable integration with electronic medical records (“EMR”) systems, providing patient surveillance management tools and outcomes data to transplant centers. See Note 5 for further details. Testing Services AlloMap Heart is a covered service for Medicare beneficiaries since January 1, 2006. In 2018, the Medicare reimbursement rate for AlloMap Heart was set at $3,240, which remains applicable for 2019. AlloMap Heart has also received positive coverage decisions from many of the largest U.S. private payers. In October 2017, the Company commercially launched AlloSure Kidney, its proprietary next generation sequencing-based test that measures dd-cfDNA in kidney transplant recipients. The Medicare reimbursement rate for AlloSure Kidney is currently $2,841. AlloSure Kidney has also received payments from private payers on a case-by-case basis. However, no positive coverage decisions have yet been made for AlloSure Kidney. In September 2018, the Company initiated the Surveillance HeartCare TM In February 2019, AlloSure® Lung became available for lung transplant patients through a compassionate use program while the test is undergoing further studies. In June 2019, the Company announced that it plans to commence the Outcomes of KidneyCare TM TM Products Olerup SSP® is used to type Human Leukocyte Antigen (“HLA”) alleles, based on the sequence specific primer (“SSP”) technology. Olerup SBT TM In May 2018, the Company entered into a License and Commercialization Agreement (the “License Agreement”) with Illumina, Inc. (“Illumina”), which provides the Company with worldwide distribution, development and commercialization rights to Illumina’s next generation sequencing (“NGS”) product line for use in transplantation diagnostic testing. Pursuant to the License Agreement, the Company is the exclusive worldwide distributor of Illumina’s TruSight ® TM TM TM Digital Following the acquisition of OTTR on May 7, 2019, CareDx is a leading provider of transplant patient tracking software (“OTTR sofware”). OTTR software provides comprehensive solutions for transplant patient management, and is currently used in over 60 leading transplant centers in the US. OTTR software enables integration with EMR systems, including Cerner and Epic, providing patient surveillance management tools and outcomes data to transplant centers. Revenue for OTTR software is included in digital and other revenue in our condensed consolidated statements of operations and was $1.1 million from the acquisition date of May 7, 2019 to June 30, 2019. Liquidity The Company has incurred significant losses and negative cash flows from operations since its inception and had an accumulated deficit of $327.2 million at June 30, 2019. As of June 30, 2019, the Company had cash and cash equivalents of $43.5 million. The Company may req uire additional financing in the future to fund working capital and pay its obligations as they come due. Additional financing might include issuance of equity securities, debt, cash from collaboration agreements or a combination of these. However, there can be no assurance that the Company will be successful in acquiring additional funding at levels sufficient to fund its operations or on terms favorable to the Company.

Summary of Significant Accounti

Summary of Significant Accounting Policies	6 Months Ended
	Jun. 30, 2019
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES The significant accounting policies and estimates used in preparation of the unaudited condensed consolidated financial statements are described in the Company’s audited consolidated financial statements as of and for the year ended December 31, 2018, and the notes thereto, which are included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2018. Material changes to the significant accounting policies previously disclosed in the Company’s Annual Report on Form 10-K for the year ended December 31, 2018 are reflected below. Basis of Presentation The accompanying unaudited condensed consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America (“U.S. GAAP”), and follow the requirements of the Securities and Exchange Commission (the “SEC”) for interim reporting. As permitted under those rules, certain notes and other financial information that are normally required by U.S. GAAP can be condensed or omitted. These unaudited condensed consolidated financial statements have been prepared on the same basis as the Company’s annual consolidated financial statements and, in the opinion of management, reflect all adjustments, consisting only of normal recurring adjustments that are necessary for a fair statement of the Company’s financial information. The condensed consolidated balance sheet as of December 31, 2018 has been derived from audited consolidated financial statements as of that date but does not include all of the financial information required by U.S. GAAP for complete financial statements. Operating results for the three and six months ended June 30, 2019 are not necessarily indicative of the results that may be expected for the year ending December 31, 2019. The accompanying unaudited condensed consolidated financial statements include the accounts of the Company and its subsidiaries. Intercompany transactions have been eliminated. Reclassifications and Changes in Presentation Certain prior period amounts have been reclassified to conform with the current period presentation, including: (i) separate presentation of debt extinguishment expenses from other expense, net, (ii) combined presentation of license and other revenue with digital revenue, (iii) combined presentation of cost of testing services and cost of product, and (iv) separate presentation of gross profit. These reclassifications had no effect on the reported results of operations. Use of Estimates The preparation of unaudited condensed consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities and the reported amounts of revenues and expenses in the unaudited condensed consolidated financial statements and accompanying notes. On an ongoing basis, management evaluates its estimates, including those related to transaction price estimates used for testing services revenue; standalone fair value of digital revenue performance obligations; accrued expenses for clinical studies; inventory valuation; the fair value of issued common stock warrants and embedded derivatives; the fair value of assets and liabilities acquired in a business combination or an assets acquisition (including identifiable intangible assets acquired); the fair value of contingent consideration recorded in connection with a business combination; the grant date fair value assumptions used to estimate stock-based compensation expense; income taxes; impairment of long-lived assets and indefinite-lived assets (including goodwill); and legal contingencies. Actual results could differ from those estimates. Concentrations of Credit Risk and Other Risks and Uncertainties For the six months ended June 30, 2019 and 2018, approximately 54% and 45%, respectively, of total revenue was derived from Medicare. No other payers or customers represented more than 10% of total revenue for these periods. As of June 30, 2019 and December 31, 2018, approximately 27% and 27%, respectively, of accounts receivable was due from Medicare. No other payer or customer represented more than 10% of accounts receivable on either June 30, 2019 or December 31, 2018. Leases Effective January 1, 2019, the Company adopted Accounting Standard Codification (“ASC”) Topic 842, Leases The present value of lease payments is determined by using the interest rate implicit in the lease, if that rate is readily determinable; otherwise, the Company uses its incremental borrowing rate. The incremental borrowing rate is determined by using the rate of interest that the Company would pay to borrow on a collateralized basis an amount equal to the lease payments for a similar term and in a similar economic environment. The Company’s leases have remaining terms of 1 year to 3.31 years, some of which include options to extend the lease term. The Company’s lease terms may include renewal options that are reasonably certain to be exercised and termination options that are reasonably certain not to be exercised. Certain finance leases also include bargain purchase options of the leased equipment. Recent Accounting Pronouncements Effective January 1, 2019, the Company adopted ASC 842 using the optional transition method and applied the standard only to leases that existed at that date. Under the optional transition method, the Company does not need to restate the comparative periods in transition and will continue to present financial information and disclosures for periods before January 1, 2019 in accordance with ASC Topic 840. The Company has also chosen to apply the package of practical expedients for existing leases, which provides relief from reassessing: (i) whether a contract is or contains a lease, (ii) lease classification, and (iii) whether initial direct costs (IDCs) can be capitalized. The Company has also made some accounting policy elections to: (i) allow the Company not to separate nonlease components from lease components, and instead to account for those as a single lease component, and (ii) elect not to recognize a ROU asset and a lease liability for leases with a term of 12 months or less (“short-term leases”). Upon adoption of ASC 842 on January 1, 2019, the Company recorded a ROU asset of approximately $3.0 million and a lease liability of approximately $3.8 million. The lease liability was determined based on the present value of the remaining minimum lease payments. The ROU asset was determined based on the value of the lease liability, adjusted for the deferred rent balances of approximately $0.8 million, which were previously included in accrued and other liabilities as well as deferred rent, net of current portion. See Note 8 for further details. The standard did not have a material impact on the condensed consolidated statement of cash flows or the condensed consolidated statement of operations. In February 2018, the Financial Accounting Standards Board (“FASB”) issued ASU No. 2018-02, Income Statement – Reporting Comprehensive Income (ASC Topic 220): Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income . In June 2018, the FASB issued ASU No. 2018-07, Compensation - Stock Compensation (ASC Topic 718): Improvements to Nonemployee Share Based Payment Accounting In August 2018, the FASB issued ASU No. 2018-15, Intangibles – Goodwill and Other – Internal – Use Software (ASC Subtopic 350-40): Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract (“ASU 2018-15”). ASU 2018-15 is effective for fiscal years beginning after December 15, 2019 and interim periods therein. Early adoption of ASU 2018-15 is permitted including adoption in any interim period. The Company plans to adopt the standard during 2019. The Company expects the new standard will impact its prospective unaudited condensed consolidated financial statements after adoption related to implementation costs in a cloud computing arrangement if and when entered by the Company. In August 2018, the FASB issued ASU 2018-13, Fair Value Measurement (ASC Topic 820) In June 2016, the FASB issued ASU 2016-13, Measurement of Credit Losses on Financial Instruments (ASC Topic 326),

Net Loss Per Share

Net Loss Per Share	6 Months Ended
	Jun. 30, 2019
Earnings Per Share [Abstract]
Net Loss Per Share	3. NET LOSS PER SHARE Basic and diluted net loss per share have been computed by dividing the net loss by the weighted-average number of common shares outstanding during the period, without consideration of common share equivalents as their effect would have been antidilutive. The following tables set forth the computation of the Company’s basic and diluted net loss per share (in thousands, except shares and per share data): Three Months Ended June 30, Six Months Ended June 30, 2019 2018 2019 2018 Numerator: Net loss attributable to CareDx, Inc. used to compute basic and diluted net loss per share $ (7,847 ) $ (14,062 ) $ (15,378 ) $ (23,031 ) Denominator: Weighted-average shares used to compute basic and diluted net loss per share attributable to CareDx, Inc. 42,132,396 35,549,837 41,873,337 32,599,032 Net loss per share attributable to CareDx, Inc.: Basic and diluted $ (0.19 ) $ (0.40 ) $ (0.37 ) $ (0.71 ) The following potentially dilutive securities have been excluded from diluted net loss per share as at June 30, 2019 because their effect would be antidilutive: Three and Six Months Ended June 30, 2019 2018 Shares of common stock subject to outstanding options 2,705,393 2,561,458 Shares of common stock subject to outstanding common stock warrants 466,695 3,328,089 Restricted stock units 1,292,440 896,904 Total common stock equivalents 4,464,528 6,786,451

Fair Value Measurements

Fair Value Measurements	6 Months Ended
	Jun. 30, 2019
Fair Value Disclosures [Abstract]
Fair Value Measurements	4. 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. 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 1: Inputs which include quoted prices in active markets for identical assets and liabilities. • Level 2: Inputs other than Level 1 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. • Level 3: 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 following table sets forth the Company’s financial assets and liabilities measured at fair value on a recurring basis, as of June 30, 2019 and December 31, 2018 (in thousands): June 30, 2019 Fair Value Measured Using (Level 1) (Level 2) (Level 3) Total Balance Assets Money market funds $ 5,428 $ — $ — $ 5,428 Liabilities Common stock warrant liability $ — $ — $ 11,286 $ 11,286 December 31, 2018 Fair Value Measured Using (Level 1) (Level 2) (Level 3) Total Balance Assets Money market funds $ 59,471 $ — $ — $ 59,471 Liabilities Common stock warrant liability $ — $ — $ 10,003 $ 10,003 The following table presents the issuances, exercises, changes in fair value and reclassifications of the Company’s Level 3 financial instruments that are measured at fair value on a recurring basis (in thousands): (Level 3) Common Balance as of December 31, 2018 $ 10,003 Exercise of warrants (3,077 ) Change in estimated fair value 4,360 Balance as of June 30, 2019 $ 11,286 The Company recognizes transfers between levels of the fair value hierarchy as of the end of the reporting period. There were no transfers between Level 1, Level 2 and Level 3 categories during the periods presented. In determining fair value, the Company uses various valuation approaches within the fair value measurement framework. The valuation methodologies used for the Company’s instruments measured at fair value and their classification in the valuation hierarchy are summarized below: • Money market funds – Investments in money market funds are classified within Level 1. At June 30, 2019 and December 31, 2018, money market funds were included on the balance sheets in cash and cash equivalents. • Common stock warrant liability – The Company utilizes a binomial-lattice pricing model (the “Monte Carlo Simulation Model”) that involves a market condition simulation to estimate the fair value of the warrants. The application of the Monte Carlo Simulation Model requires the use of a number of complex assumptions including the Company’s stock price, expected life of the warrants, stock price volatility determined from the Company’s historical stock prices and stock prices of peer companies in the diagnostics industry, and risk-free rates based on the implied yield currently available in the U.S. Treasury zero-coupon issues with a remaining term equal to the expected life of the warrants. Increases (decreases) in the assumptions discussed above result in a directionally similar impact to the fair value of the common stock warrant liability. Common Stock Warrant Liability Valuation Assumptions June 30, 2019 December 31, 2018 Private Placement Common Stock Warrant Liability Stock Price $ 35.99 $ 25.14 Exercise Price $ 1.12 $ 1.12 Remaining term (in years) 3.79 4.29 Volatility 84.00 % 79.00 % Risk-free interest rate 1.71 % 2.46 %

Business Combinations

Business Combinations	6 Months Ended
	Jun. 30, 2019
Business Combinations [Abstract]
Business Combinations	5. BUSINESS COMBINATIONS On May 7, 2019, the Company acquired 100% of the outstanding common stock of OTTR for total consideration of $16.1 million. OTTR was formed in 1993 and is a leading provider of organ transplant patient tracking software. Following the acquisition, the company changed OTTR’s legal name to “CareDx Transplant Management, Inc.” The OTTR software provides comprehensive solutions for transplant patient management, and is currently used in over 60 leading transplant centers in the U.S. The OTTR software enables integration with EMR systems, including Cerner and Epic, providing patient surveillance management tools and outcomes data to transplant centers. The Company accounted for the transaction as a business combination using the acquisition method of accounting. Results of operations of OTTR have been included with the Company’s results since the date of the acquisition. Acquisition-related costs of $0.6 million associated with the acquisition were expensed as incurred, and classified as part of general and administrative expenses in the condensed consolidated statement of operations. Goodwill of $10.6 million arising from the acquisition primarily consists of synergies from combining the OTTR software with the current testing solutions offered by the Company. The integration of the OTTR software into transplant center EMR systems may simplify the ordering process for the Company’s leading surveillance tests, optimize transplant patient safety, increase efficiency and facilitate compliance. None of the goodwill is expected to be deductible for income tax purposes. All of the goodwill has been assigned to the Company’s existing operating segment. The following table summarizes the consideration paid for OTTR and the provisional amounts of the assets acquired and liabilities assumed recognized at their estimated fair value at the acquisition date: Total (In Thousands) Consideration Cash $ 16,037 Accrued purchase consideration 111 Total Consideration $ 16,148 Recognized amounts of identifiable assets acquired and liabilities assumed Current assets $ 1,525 Fixed assets 35 Identifiable intangible assets 6,600 Current liabilities (2,566 ) Total identifiable net assets acquired 5,594 Goodwill 10,554 $ 16,148 The allocation of the purchase price to assets acquired and liabilities assumed, was based on the Company’s best estimate of the fair value of such assets and liabilities as of the acquisition date. The fair value of the acquired current liabilities includes $2.3 million of deferred revenue. Such amount is preliminary and it will be adjusted in subsequent periods upon completion of a detailed analysis of revenue contracts. At the acquisition date the Company estimated net deferred tax assets of approximately $0.2 million arising from temporary differences related to assets acquired and liabilities assumed. The Company estimated that OTTR had net operating losses (“NOLs”) carryforward of approximately $6.9 million, $4.3 million of which will begin to expire in year 2033, and the remaining $2.6 million will be carried forward indefinitely. A full valuation allowance of $0.2 million was recognized as of the acquisition date resulting in no impact from deferred taxes to OTTR’s opening balance. An Internal Revenue Code Section 382 study (“Section 382 study”) for NOLs is expected to be finalized by the Company during the third quarter of 2019 and therefore deferred taxes acquired are preliminary amounts as of June 30, 2019. The following table summarizes the fair values of the intangible assets acquired as of the acquisition date (in thousands): Estimated Fair Value Estimated Useful Lives (Years) Customer relationships $ 4,200 15 Developed technology 2,300 10 Trademark 100 2 Total $ 6,600 Customer relationships acquired by the Company represent the fair value of future projected revenue that is expected to be derived from sales of OTTR’s products to existing customers. The customer relationships’ fair value has been estimated utilizing a multi-period excess earnings method under the income approach, which reflects the present value of the projected cash flows that are expected to be generated by the customer relationships, less charges representing the contribution of other assets to those cash flows that use projected cash flows with and without the intangible asset in place. The economic useful life was determined based on the distribution of the present value of the cash flows attributable to the intangible asset. The acquired developed technology represents the fair value of OTTR’s proprietary software. The trademark acquired consists primarily of the OTTR brand and markings. Both the developed technology and the trademark were fair valued using the relief-from-royalty method under the income approach. This method considers the value of the asset is the value of the royalty payments from which the Company is relieved due to its ownership of the asset. The royalty rates of 15% and 1% were used to estimate the fair value the developed technology and the trademark, respectively. The Company utilized a discount rate of 14.5% in estimating the fair value of these three intangible assets. As of June 30, 2019, OTTR’s digital revenue and net loss of $1.1 million and $0.1 million, respectively were included in the Company’s condensed consolidated statement of operations from the acquisition date of May 7, 2019. Unaudited supplemental pro forma information is not disclosed because it is considered immaterial.

Goodwill and Intangible Assets

Goodwill and Intangible Assets	6 Months Ended
	Jun. 30, 2019
Goodwill And Intangible Assets Disclosure [Abstract]
Goodwill and Intangible Assets	6. GOODWILL AND INTANGIBLE ASSETS Goodwill Goodwill is recorded when the purchase price of an acquisition exceeds the fair value of the net tangible and identified intangible assets acquired. Goodwill is tested annually for impairment at the reporting unit level during the fourth quarter or earlier upon the occurrence of certain events or substantive changes in circumstances. There were no indicators of impairment in the three and six months ended June 30, 2019. Total Balance as of January 1, 2019 $ 12,005 Goodwill acquired 10,554 Balance as of June 30, 2019 $ 22,559 Intangible Assets The following tables present details of the Company’s intangible assets as of June 30, 2019 (in thousands): June 30, 2019 Gross Carrying Amount Accumulated Amortization Foreign Currency Translation Net Amount Weighted Average Remaining Useful (In Intangible assets with finite lives: Customer relationships: Allenex $ 12,650 $ (2,573 ) $ (1,489 ) $ 8,588 11.5 Customer relationships: Conexio 28 (11 ) (2 ) 15 1.5 Customer relationships: TruSight HLA 380 (160 ) — 220 1.8 Developed technology: Olerup SSP 11,650 (3,588 ) (1,246 ) 6,816 6.5 Acquired technology: QTYPE 4,510 (809 ) (519 ) 3,182 11.5 Acquired technology: Olerup SBT 127 (51 ) (6 ) 70 1.5 Acquired technology: dd-cfDNA 6,650 (889 ) — 5,761 11.6 Trademarks 2,360 (529 ) (195 ) 1,636 6.7 Customer relationships: OTTR 4,200 (47 ) — 4,153 14.8 Developed technology: OTTR 2,300 (38 ) — 2,262 9.8 Commercialization rights of Cibiltech 8,079 — — 8,079 9.9 Total intangible assets with finite lives $ 52,934 $ (8,695 ) $ (3,457 ) $ 40,782 Acquired in-process technology: AlloSeq Tx 2,719 — — 2,719 — Acquired in-process technology: AlloSeq HCT 2,103 — — 2,103 — Total intangible assets $ 57,756 $ (8,695 ) $ (3,457 ) $ 45,604 Acquisition of intangible assets Illumina License and Commercialization Agreement On May 4, 2018, the Company entered into the License Agreement with Illumina, which provides the Company with certain worldwide distribution, development and commercialization rights to Illumina’s NGS product line for use in the field of bone marrow and solid organ transplantation diagnostic testing (the “Field”). As a result, The License Agreement required the Company to make a $5.0 million initial cash payment to Illumina and further requires the Company to pay royalties in the mid-single to low-double digits on sales of future commercialized products. Pursuant to the License Agreement, the Company is obligated to complete timely development and commercialization of other NGS product lines for use in the Field, and has agreed to minimum purchase commitments of finished products and raw materials from Illumina through 2023. As the License Agreement did not meet the definition of a business combination under ASC Topic 805, Business Combinations, Costs relating to the assets acquired were $5.2 million, comprising of the cash consideration of $5.0 million and associated transaction costs of $0.2 million. A deferred tax balance was not required to be established on the License Agreement date as the book and tax basis of the intangible assets was equivalent to the amount paid. The allocation of the purchase price to identified intangible assets acquired was based on the Company’s best estimate of the fair value of such assets as of the acquisition date. Significant assumptions utilized in the valuation of identified intangible assets were based on company-specific information and projections, which are not observable in the market and are thus considered Level 3 measurements as defined by U.S. GAAP. Customer relationships represent the fair value of future projected revenue that is expected to be derived from sales of TruSight HLA products to existing customers of Illumina. The customer contracts and related relationships value has been estimated utilizing a multi-period excess earnings method under income approach, which reflects the present value of the projected cash flows that are expected to be generated by the customer relationships less charges representing the contribution of other assets to those cash flows that use projected cash flows with and without the intangible asset in place. The economic useful life was determined based on the life of the products, assuming that the existing customers will remain with the Company until the products becomes obsolete. The Company utilized a discount rate of 18% in estimating the fair value of the customer relationships. The acquired in-process technology represents the fair value of products in development that have not reached commercial production at the date of acquisition. The fair value of the products was also determined using the multi-period excess earnings method under income approach. A rate of 30% and 40% for the AlloSeq Tx acquired in-process technology and the AlloSeq HCT acquired in-process technology, respectively, was utilized to discount the cash flows to the present value. The acquired in-process technology will not be amortized until completion of the related products, which is determined to occur when the products commence commercial production. Upon completion, each acquired in-process technology product will be amortized over its estimated useful life. The following table summarizes the fair values of the intangible assets acquired as of the closing date (in thousands): Estimated Fair Value Estimated Useful Lives (Years) Customer relationships: TruSight HLA $ 380 2.6 Acquired in-process technology: AlloSeq Tx 2,719 — Acquired in-process technology: AlloSeq HCT 2,103 — Total $ 5,202 Cibiltech License and Commercialization Agreement Effective April 30, 2019, the Company entered into a license and commercialization agreement (the “Cibiltech Agreement”) with Cibiltech SAS (“Cibiltech”). Cibiltech is a French company engaged in the development and support of predictive medicine and artificial intelligence software, services and technology, with an emphasis on personalized patient care and clinical research, including its proprietary software and service offering known as Predigraft (or KidneyCare iBox in the U.S.) for the predictive analysis of post-transplantation kidney allograft loss. The Cibiltech Agreement provides the Company with an irrevocable, non-transferable right to commercialize Cibiltech’s proprietary software in the field of transplantation in the U.S. for a period of ten years. The Company estimated the fair value of the acquired commercialization rights intangible asset based on expected contractual payments discounted to present value using a discount rate of 6%. On July 26, 2019, pursuant to the Cibiltech Agreement, the Company purchased $1.0 million of convertible preferred shares of Cibiltech and does not have a significant influence on Cibiltech’s operations. The following table present details of the Company’s intangible assets as of December 31, 2018 (in thousands): December 31, 2018 Gross Carrying Amount Accumulated Amortization Foreign Currency Translation Net Amount Weighted Average Remaining Useful (In Intangible assets with finite lives: Customer relationships: Allenex $ 12,650 $ (2,198 ) $ (1,129 ) $ 9,323 12.0 Customer relationships: Conexio 28 (6 ) (2 ) 20 2.0 Customer relationships: TruSight HLA 380 (86 ) — 294 2.0 Developed technology: Olerup SSP 11,650 (3,065 ) (998 ) 7,587 7.0 Acquired technology: QTYPE 4,510 (671 ) (407 ) 3,432 12.0 Acquired technology: Olerup SBT 127 (28 ) (6 ) 93 2.0 Acquired technology: dd-cfDNA 6,650 (635 ) — 6,015 11.8 Trademarks 2,260 (454 ) (140 ) 1,666 12.0 Total intangible assets with finite lives $ 38,255 $ (7,143 ) $ (2,682 ) $ 28,430 Acquired in-process technology: AlloSeq Tx 2,719 — — 2,719 — Acquired in-process technology: AlloSeq HCT 2,103 — — 2,103 — Total intangible assets $ 43,077 $ (7,143 ) $ (2,682 ) $ 33,252 Amortization expense was $0.7 million and $0.6 million for the three months ended June 30, 2019 and 2018, respectively. For the three months ended June 30, 2019, expenses of $0.4 million and $0.3 million were amortized to cost of product and sales and marketing expense, respectively. For the three months ended June 30, 2018, expenses of $0.4 million and $0.2 million were amortized to cost of product and sales and marketing expense, respectively. Amortization expense was $1.3 million and $1.2 million for the six months ended June 30, 2019 and 2018, respectively. For the six months ended June 30, 2019, expenses of $0.7 million and $0.6 million were amortized to cost of product and sales and marketing expense, respectively. For the six months ended June 30, 2018, expenses of $0.7 million and $0.5 million were amortized to cost of product and sales and marketing expense, respectively. The following table summarizes the Company’s estimated future amortization expense of intangible assets with finite lives as of June 30, 2019 (in thousands): Years Ending December 31, Cost of Revenue Sales and Marketing Total Remainder of 2019 $ 1,392 $ 687 $ 2,079 2020 2,918 1,373 4,291 2021 2,871 1,183 4,054 2022 2,871 1,166 4,037 2023 2,871 1,166 4,037 Thereafter 13,245 9,039 22,284 Total future amortization expense $ 26,168 $ 14,614 $ 40,782 The Company evaluates the carrying value of the intangible assets, not subject to amortization, related to acquired in-process technology assets, which are considered to be indefinite‑lived until the completion or abandonment of the associated research and development efforts. Accordingly, amortization of the acquired in-process technology assets will not occur until the products reach commercialization. During the period the assets are considered indefinite‑lived, they are tested for impairment on an annual basis, as well as between annual tests if the Company becomes aware of any events occurring or changes in circumstances that would indicate that the fair values of the acquired in-process technology assets are less than their carrying amounts. An impairment loss would be recorded when the fair value of an acquired in-process technology assets is less than its carrying value. If and when development is complete, which generally occurs when the products are made commercially available, the associated acquired in-process technology asset will be deemed definite‑lived and will then be amortized based on its estimated useful life.

Balance Sheet Components

Balance Sheet Components	6 Months Ended
	Jun. 30, 2019
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Balance Sheet Components	7. BALANCE SHEET COMPONENTS Inventory Inventory consisted of the following (in thousands): June 30, 2019 December 2018 Finished goods $ 2,519 $ 2,506 Work in progress 940 651 Raw materials 1,882 1,786 Total inventory $ 5,341 $ 4,943 Accrued and other liabilities Accrued and other liabilities consisted of the following (in thousands): June 30, 2019 December 2018 Deferred revenue $ 3,624 $ 39 Short-term lease liability 2,034 — Deferred payments for intangible assets 2,000 — Clinical studies 1,993 1,815 Test sample processing fees 782 657 Accrued royalty 696 285 Professional fees 596 822 Other accrued expenses 2,025 2,019 Total accrued and other liabilities $ 13,750 $ 5,637

Commitments

Commitments	6 Months Ended
	Jun. 30, 2019
Commitments And Contingencies Disclosure [Abstract]
Commitments	8. COMMITMENTS Leases The Company leases its operating and office facilities for various terms under long-term, non-cancelable operating lease agreements in Brisbane, California; West Chester, Pennsylvania; Omaha, Nebraska; Fremantle, Australia and Stockholm, Sweden. The lease for the Company’s facility in Vienna, Austria is on a month-to-month basis. The facility leases expire at various dates through 2022. In the normal course of business, it is expected that these leases will be renewed or replaced by leases on other properties. The following table summarizes the lease cost for the three and six months ended June 30, 2019 (in thousands): Three Months ended June 30, Six Months ended June 30, 2019 2019 Operating lease cost $ 455 $ 905 Finance lease cost 55 110 Total lease cost $ 510 $ 1,015 Other information: Weighted-average remaining lease term - Operating leases (in years) 1.7 Weighted-average remaining lease term - Finance leases (in years) 1.9 Weighted-average discount rate - Operating leases (%) 10.5 % Weighted-average discount rate - Finance leases (%) 6.5 % Rent expense under the non-cancelable operating leases was $0.5 million and $0.4 million for the three months ended June 30, 2019 and 2018, respectively. Rent expense under the non-cancelable operating leases $0.9 million for each of the six months ended June 30, 2019 and 2018. Future minimum lease commitments under these operating and finance leases as of June 30, 2019, are as follows (in thousands): Years Ending December 31, Finance Leases Operating Leases Remainder of 2019 $ 105 $ 1,140 2020 209 2,310 2021 71 223 2022 — 97 Total future minimum lease payments $ 385 $ 3,770 The current portion of obligations under finance leases is included in accrued and other liabilities on the condensed consolidated balance sheets. The long-term portion is included in other liabilities on the condensed consolidated balance sheets. Royalty Commitments The Board of Trustees of the Leland Stanford Junior University (“Stanford”) In June 2014, the Company entered into a license agreement with Stanford (the “Stanford License”), which granted the Company an exclusive license to a patent relating to the diagnosis of rejection in organ transplant recipients using dd-cfDNA. Under the terms of the Stanford License, the Company is required to pay an annual license maintenance fee, six milestone payment amounts and royalties in the low single digits of net sales of products incorporating the licensed technology. The license maintenance fee may be offset against earned royalty payments due on net sales in that year. The Company incurred royalties of $0.3 million and $0.4 million in the three and six months ended June 30, 2019, respectively. Illumina On May 4, 2018, the Company entered into the License Agreement with Illumina. The License Agreement requires the Company to pay royalties in the mid-single to low-double digits on sales of future commercialized products. In the three and six months ended June 30, 2019, the Company paid no royalties to Illumina. Cibiltech Commitments Pursuant to the Cibiltech Agreement, as discussed in Note 6, the Company will share an agreed percentage of revenue with Cibiltech, if and when revenues are generated from KidneyCare iBox. Other Commitments Pursuant to the License Agreement with Illumina, the Company is obligated to complete timely development and commercialization of other NGS product lines for use in the Field, and has agreed to minimum purchase commitments of finished products and raw materials from Illumina through 2023. Litigation From time to time, the Company may become involved in litigation and other legal actions. The Company estimates the range of liability related to any pending litigation where the amount and range of loss can be estimated. The Company records its best estimate of a loss when the loss is considered probable. Where a liability is probable and there is a range of estimated loss with no best estimate in the range, the Company records a charge equal to at least the minimum estimated liability for a loss contingency when both of the following conditions are met: (i) information available prior to issuance of the financial statements indicates that it is probable that a liability had been incurred at the date of the financial statements and (ii) the range of loss can be reasonably estimated. In the normal course of business, the Company enters into contracts and agreements that contain a variety of representations and warranties and provide for indemnification for certain liabilities. The exposure under these agreements is unknown because it involves claims that may be made against the Company in the future but have not yet been made. To date, the Company has not paid any claims or been required to defend any action related to its indemnification obligations. However, the Company may record charges in the future as a result of these indemnification obligations. The Company also has indemnification obligations to its directors and executive officers for specified events or occurrences, subject to some limits, while they are serving at the Company’s request in such capacities. There have been no claims to date and the Company believes the fair value of these indemnification agreements is minimal. Accordingly, the Company has not recorded any liabilities for these agreements as of June 30, 2019 and as of December 31, 2018.

Debt

Debt	6 Months Ended
	Jun. 30, 2019
Transfers And Servicing [Abstract]
Debt	9. DEBT The Company did not have any outstanding debt as of June 30, 2019 or December 31, 2018. Perceptive Credit Agreement On April 17, 2018, the Company entered into a credit agreement with Perceptive Credit Holdings II, LP (the “Perceptive Credit Agreement”) for an initial term loan of $15.0 million. On November 20, 2018, the Company paid off all obligations owing under, and terminated, the Perceptive Credit Agreement. The Perceptive Credit Agreement debt extinguishment resulted in a $3.0 million loss that was included in debt extinguishment expenses, in the condensed consolidated statements of operations. JGB Debt In February and March 31, 2018, JGB Collateral LLC and certain of its affiliates (“JGB”) converted the remaining $26.7 million of principal and accrued interest of the Company’s convertible debt (the “JGB Debt”) into an aggregate of 6,161,331shares of the Company’s common stock. In connection with these conversions in the three months ended March 31, 2018, the Company recognized $6,000 to common stock and $38.8 million to additional paid in capital; the unamortized debt discount of $2.7 million was extinguished; and the compound derivative liability of $12.1 million was also extinguished. The JGB Debt conversion resulted in a $2.8 million loss on debt extinguishment that was included in debt extinguishment expenses in the condensed consolidated statements of operations for the three months ended March 31, 2018. Danske Bank Term Loan and Credit Facility The Company repaid the full outstanding amount of SEK 47,000,000 (approximately $5.6 million) plus accrued interest of SEK 142,000 (approximately $17,000), under the Danske Term Loan and Credit Facility on April 17, 2018. FastPartner Subordinated Promissory Notes The Company repaid the full amount outstanding of SEK 21,300,000 (approximately $2.5 million), including accrued interest of SEK 1,600,000 (approximately $0.2 million), under the FastPartner Note Agreement on April 17, 2018. Mohammed Al Amoudi Subordinated Promissory Note The Company repaid the full amount outstanding of SEK 15,700,000 (approximately $1.9 million), including accrued interest of SEK 1,200,000 (approximately $0.1 million) under the Al Amoudi Note Agreement on April 17, 2018. Loan Agreement with SSP Primers Aktieboulag The Company repaid the full loan amount outstanding of SEK 10,000,000 (approximately $1.2 million), including accrued interest of SEK 650,000 (approximately $0.1 million) on February 26, 2018.

Stockholders' Equity

Stockholders' Equity	6 Months Ended
	Jun. 30, 2019
Stockholders Equity Note [Abstract]
Stockholders' Equity	10. STOCKHOLDERS’ EQUITY Contingent Consideration Liability The Company had a contingent obligation to issue 227,845 shares of the Company’s common stock to the former owners of ImmuMetrix, Inc. (“IMX”), in conjunction with its acquisition of IMX in June 2014. The shares were issuable upon the Company completing 2,500 commercial tests involving the measurement of dd-cfDNA in organ transplant recipients in the United States by June 10, 2020. The Company achieved the contingent consideration milestone of 2,500 commercial tests and issued the 227,848 shares in May 2018. 2018 Public Offering On November 16, 2018, the Company sold in the 2018 Public Offering an aggregate of 2,300,000 shares of its common stock, including 300,000 shares sold pursuant to the underwriters’ full exercise of their option to purchase additional shares at a public offering price of $24.50 per share. Total net proceeds received were $52.9 million net of underwriter’s fees and issuance costs.

401(K) Plan

401(K) Plan	6 Months Ended
	Jun. 30, 2019
Compensation And Retirement Disclosure [Abstract]
401(K) Plan	11. 401(K) PLAN The Company sponsors a 401(k) defined contribution plan covering all U.S. employees under the Internal Revenue Code of 1986, as amended. Employee contributions are voluntary and are determined on an individual basis subject to the maximum allowable under federal tax regulations. On January 1, 2018, the Company began to make contributions to the employee plan. The Company incurred expenses related to contributions to the plan of $0.1 million for each of the three months ended June 30, 2019 and 2018, respectively. The Company incurred expenses related to contributions to the plan of $0.3 million and $0.1 million for the six months ended June 30, 2019 and 2018, respectively.

Warrants

Warrants	6 Months Ended
	Jun. 30, 2019
Warrants [Abstract]
Warrants	12. WARRANTS The Company issues common stock warrants in connection with debt or equity financings to a lender, a placement agent or an investor. Issued warrants are considered standalone financial instruments and the terms of each warrant are analyzed for equity or liability classification in accordance with U.S. GAAP. Warrants that are classified as liabilities usually have various features that would require net-cash settlement by the Company. Warrants that are not liabilities, derivatives and/or meet the exception criteria are classified as equity. Warrants liabilities are remeasured at fair value at each period end with changes in fair value recorded in the condensed consolidated statements of operations until expired or exercised. The Company utilizes the Monte Carlo Simulation Model to estimate the fair value of its warrants. Refer to Note 4 for further details. Warrants that are classified as equity are valued at fair value on the date of issuance, recorded in additional paid in capital and not remeasured. In the three months ended June 30, 2019, warrants to purchase approximately 24,000 shares of common stock were exercised for cash payments of less than $0.1 million. During the three months ended June 30, 2019, warrants to purchase approximately 40,000 shares of common stock were exercised on a cashless basis and approximately 15,000 shares were issued pursuant to the exercises. In the six months ended June 30, 2019, warrants to purchase approximately 94,000 shares of common stock were exercised for cash payments of $0.1 million. During the six months ended June 30, 2019, approximately 96,000 warrants were exercised on a cashless basis and approximately 40,000 shares were issued pursuant to the exercises. In the three months ended June 30, 2018, warrants to purchase approximately 445,000 shares of common stock were exercised for a cash payments of $0.5 million. In the six months ended June 30, 2018, warrants to purchase approximately 468,000 shares of common stock were exercised for a cash payments of $0.5 million. As of June 30, 2019, outstanding warrants to purchase common stock were: Classified as Original Term Exercise Price Number of Shares Underlying Warrants Original issue date: August 2012 Equity 7 years $ 21.78 111,455 January 2015 Equity 5 years $ 6.96 34,483 April 2016 Liability 7 years $ 1.12 320,757 466,695

Stock Incentive Plans

Stock Incentive Plans	6 Months Ended
	Jun. 30, 2019
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock Incentive Plans	13. STOCK INCENTIVE PLANS Stock Options and Restricted Stock Units (“RSU”) The following table summarizes option and unvested RSU activity under the Company’s 2014 Equity Incentive Plan and 2016 Inducement Equity Incentive Plan and related information: Shares Available for Grant Stock Options Outstanding Weighted- Average Exercise Price Number of RSU Shares Weighted- Average Grant Date Fair Value Balance—December 31, 2018 322,178 2,501,057 $ 9.10 968,364 $ 11.49 Additional options authorized 1,655,398 — — — — Common stock awards for services (3,626 ) — — — — RSUs granted (856,965 ) — — 856,965 27.37 RSUs vested — — — (439,704 ) 13.14 Options granted (831,860 ) 831,860 28.11 — — Options exercised — (491,581 ) 5.64 — — Repurchase of common stock under employee incentive plans 133,913 — — — — RSUs forfeited 93,185 — — (93,185 ) 20.60 Options forfeited 134,504 (134,504 ) 11.76 — — Options expired 1,439 (1,439 ) 3.86 — — Balance—June 30, 2019 648,166 2,705,393 1,292,440 The total intrinsic value of options exercised was $6.0 million and $12.0 million in the three and six months ended June 30, 2019, respectively. As of June 30, 2019, the total intrinsic value of outstanding RSUs was approximately $46.5 million and there were $22.6 million of unrecognized compensation costs related to RSUs, which are expected to be recognized over a weighted-average period of 2.94 years. Options outstanding that have vested and are expected to vest at June 30, 2019 are as follows: Number of Shares Weighted-Average Exercise Price Weighted-Average Remaining Contractual Life (Years) Aggregate Intrinsic (In Vested 903,539 $ 15.44 6.64 $ 26,697 Expected to vest 1,681,317 19.97 9.22 26,984 Total 2,584,856 $ 53,681 The aggregate intrinsic value is calculated as the difference between the exercise price of the underlying stock options and the fair value of the Company’s common stock at June 30, 2019 for stock options that were in-the-money. The total fair value of options that vested during the three and six months period ended June 30, 2019 was $1.2 million and $1.7 million, respectively. As of June 30, 2019, there were approximately $19.3 million of unrecognized compensation costs related to stock options, which are expected to be recognized over a weighted-average period of 3.42 years. 2014 Employee Stock Purchase Plan The Company has an Employee Stock Purchase Plan (the “ESPP”), under which employees can purchase shares of its common stock based on a percentage of their compensation, but not greater than 15% of their earnings; provided, however, an eligible employee’s right to purchase shares of the Company’s common stock may not accrue at a rate which exceeds $25,000 of the fair market value of such shares for each calendar year in which such rights are outstanding. The ESPP has consecutive offering periods of approximately six months in length. The purchase price per share must be equal to the lower of 85% of the fair value of the common stock on the first day of the offering period or on the exercise date. During the offering period in 2018 that ended on December 31, 2018, 31,184 shares were purchased for aggregate proceeds of $0.3 million from the issuance of shares, which occurred on January 2, 2019. During the offering period in 2019 that ended on June 30, 2019, 20,528 shares were purchased for aggregate proceeds of $0.4 million from the issuance of shares, which occurred on July 1, 2019. Valuation Assumptions The estimated fair values of employee stock options and ESPP shares were estimated using the Black-Scholes option-pricing model based on the following weighted-average assumptions: Three Months Ended June 30, Six Months Ended June 30, 2019 2018 2019 2018 Employee stock options Expected term (in years) 6.0 6.0 6.0 6.0 Expected volatility 71.00 % 66.00 % 70.72 % 68.75 % Risk-free interest rate 2.34 % 2.76 % 2.43 % 2.71 % Expected dividend yield — % — % — % — % Employee stock purchase plan Expected term (in years) 0.50 0.5 0.50 0.5 Expected volatility 76.66 % 105.32 % 76.66 % 105.32 % Risk-free interest rate 2.51 % 1.61 % 2.51 % 1.61 % Expected dividend yield — % — % — % — % Risk-free Interest Rate : Volatility: The Company used an average historical stock price volatility of its own stock and those comparable public companies that were deemed to be representative of future stock price trends. Expected Term: The expected term represents the period for which the Company’s stock-based compensation awards are expected to be outstanding and is based on analyzing the vesting and contractual terms of the awards and the holders’ historical exercise patterns and termination behavior. Expected Dividends: The Company has not paid and does not anticipate paying any dividends in the near future. Stock-based Compensation Expense The following table summarizes stock-based compensation expense relating to employee and nonemployee stock-based awards for the three and six months ended June 30, 2019 and 2018, included in the condensed consolidated statements of operations as follows (in thousands): Three Months Ended June 30, Six Months Ended June 30, 2019 2018 2019 2018 Cost of revenue $ 508 $ 191 $ 1,280 $ 252 Research and development 1,441 462 2,273 675 Sales and marketing 940 466 1,671 529 General and administrative 2,103 1,393 5,821 1,761 Total $ 4,992 $ 2,512 $ 11,045 $ 3,217 No tax benefit was recognized related to share-based compensation expense since the Company has never reported taxable income and has established a full valuation allowance to offset all of the potential tax benefits associated with its deferred tax assets. In addition, no amounts of stock-based compensation expense were capitalized for the periods presented.

Income Taxes

Income Taxes	6 Months Ended
	Jun. 30, 2019
Income Tax Disclosure [Abstract]
Income Taxes	14. INCOME TAXES The Company’s effective tax rate may vary from the U.S. federal statutory tax rate due to the change in the mix of earnings in tax jurisdictions with different statutory rates, benefits related to tax credits and the tax impact of non-deductible expenses and other permanent differences between income before income taxes and taxable income. For the three and six months ended June 30, 2019, the Company recorded an income tax benefit of $0.2 million and $0.8 million, respectively, compared to $0.4 million and $0.8 million for the three and six month ended June 30, 2018, respectively. The income tax benefit of $0.2 million and $0.8 million for the three and six month ended June 30, 2019, respectively, is primarily attributable to the recognition of deferred tax assets from foreign losses. The Company assesses the realizability of its net deferred tax assets by evaluating all available evidence, both positive and negative, including (i) cumulative results of operations in recent years, (ii) sources of recent losses, (iii) estimates of future taxable income, and (iv) the length of net operating loss carryforward periods. The Company believes that based on the history of its U.S. losses and other factors, the weight of available evidence indicates that it is more likely than not that it will not be able to realize its U.S. net deferred tax assets. Accordingly, the U.S. net deferred tax assets have been offset by a full valuation allowance. Starting in 2018, companies may be subject to global intangible low tax income (“GILTI”), which is a tax on foreign income in excess of a deemed return on tangible assets of foreign corporations as well as the new base erosion anti-abuse tax (“BEAT”) under the Tax Act. GILTI will be effectively taxed at a tax rate of 10.5%. Due to the complexity of the GILTI tax rules, companies are allowed to make an accounting policy choice of either (1) treating taxes due on future U.S. inclusions in taxable income related to GILTI as a current-period expense when incurred or (2) factoring such amounts into a company’s measurement of its deferred taxes under SAB 118. The Company has not yet made an election with respect to GILTI and does not believe GILTI will have an impact on the Company’s 2019 taxes. The Company will continue to review the GILTI and BEAT rules to determine their applicability to the Company as the rules become effective.

Segment Reporting

Segment Reporting	6 Months Ended
	Jun. 30, 2019
Segment Reporting [Abstract]
Segment Reporting	15. SEGMENT REPORTING Operating segments are defined as components of an enterprise for which separate financial information is available that is evaluated regularly by the Company’s Chief Operating Decision Maker (“CODM”), or decision making group, whose function is to allocate resources to and assess the performance of the operating segments. The Company has identified its Chief Executive Officer as the CODM. The Company operates in a single reportable segment. The OTTR acquisition will be integrated into the Company’s single reporting unit. Revenues by geographic regions are based upon the customers’ ship-to address for product revenue and the region of testing for testing services revenue. The following table summarizes reportable revenues by geographic regions (in thousands): Three Six 2019 2018 2019 2018 Testing services revenue United States $ 25,499 $ 13,853 $ 46,885 $ 24,313 Rest of the World 178 144 310 288 $ 25,677 $ 13,997 $ 47,195 $ 24,601 Product revenue United States $ 2,168 $ 1,319 $ 4,000 $ 2,164 Europe 1,906 1,688 3,849 3,661 Rest of the World 519 543 1,177 1,032 $ 4,593 $ 3,550 $ 9,026 $ 6,857 Digital and other revenue United States $ 1,108 $ 235 $ 1,130 $ 377 Europe 50 41 60 41 Rest of the World 26 — 25 — $ 1,184 $ 276 $ 1,215 $ 418 Total United States $ 28,775 $ 15,407 $ 52,015 $ 26,854 Total Europe $ 1,956 $ 1,729 $ 3,909 $ 3,702 Total Rest of the World $ 723 $ 687 $ 1,512 $ 1,320 Total $ 31,454 $ 17,823 $ 57,436 $ 31,876 The following table summarizes long-lived assets, consisting of property and equipment, net, by geographic regions (in thousands): June 30, 2019 December Long-lived assets: United States $ 2,712 $ 3,235 Europe 498 625 Rest of the World 298 274 Total $ 3,508 $ 4,134

Organization and Description _2

Organization and Description of Business (Policies)	6 Months Ended
	Jun. 30, 2019
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Liquidity	Liquidity The Company has incurred significant losses and negative cash flows from operations since its inception and had an accumulated deficit of $327.2 million at June 30, 2019. As of June 30, 2019, the Company had cash and cash equivalents of $43.5 million. The Company may req uire additional financing in the future to fund working capital and pay its obligations as they come due. Additional financing might include issuance of equity securities, debt, cash from collaboration agreements or a combination of these. However, there can be no assurance that the Company will be successful in acquiring additional funding at levels sufficient to fund its operations or on terms favorable to the Company.
Basis of Presentation	Basis of Presentation The accompanying unaudited condensed consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America (“U.S. GAAP”), and follow the requirements of the Securities and Exchange Commission (the “SEC”) for interim reporting. As permitted under those rules, certain notes and other financial information that are normally required by U.S. GAAP can be condensed or omitted. These unaudited condensed consolidated financial statements have been prepared on the same basis as the Company’s annual consolidated financial statements and, in the opinion of management, reflect all adjustments, consisting only of normal recurring adjustments that are necessary for a fair statement of the Company’s financial information. The condensed consolidated balance sheet as of December 31, 2018 has been derived from audited consolidated financial statements as of that date but does not include all of the financial information required by U.S. GAAP for complete financial statements. Operating results for the three and six months ended June 30, 2019 are not necessarily indicative of the results that may be expected for the year ending December 31, 2019. The accompanying unaudited condensed consolidated financial statements include the accounts of the Company and its subsidiaries. Intercompany transactions have been eliminated.
Reclassifications and Changes in Presentation	Reclassifications and Changes in Presentation Certain prior period amounts have been reclassified to conform with the current period presentation, including: (i) separate presentation of debt extinguishment expenses from other expense, net, (ii) combined presentation of license and other revenue with digital revenue, (iii) combined presentation of cost of testing services and cost of product, and (iv) separate presentation of gross profit. These reclassifications had no effect on the reported results of operations.
Use of Estimates	Use of Estimates The preparation of unaudited condensed consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities and the reported amounts of revenues and expenses in the unaudited condensed consolidated financial statements and accompanying notes. On an ongoing basis, management evaluates its estimates, including those related to transaction price estimates used for testing services revenue; standalone fair value of digital revenue performance obligations; accrued expenses for clinical studies; inventory valuation; the fair value of issued common stock warrants and embedded derivatives; the fair value of assets and liabilities acquired in a business combination or an assets acquisition (including identifiable intangible assets acquired); the fair value of contingent consideration recorded in connection with a business combination; the grant date fair value assumptions used to estimate stock-based compensation expense; income taxes; impairment of long-lived assets and indefinite-lived assets (including goodwill); and legal contingencies. Actual results could differ from those estimates.
Concentrations of Credit Risk and Other Risks and Uncertainties	Concentrations of Credit Risk and Other Risks and Uncertainties For the six months ended June 30, 2019 and 2018, approximately 54% and 45%, respectively, of total revenue was derived from Medicare. No other payers or customers represented more than 10% of total revenue for these periods. As of June 30, 2019 and December 31, 2018, approximately 27% and 27%, respectively, of accounts receivable was due from Medicare. No other payer or customer represented more than 10% of accounts receivable on either June 30, 2019 or December 31, 2018.
Leases	Leases Effective January 1, 2019, the Company adopted Accounting Standard Codification (“ASC”) Topic 842, Leases The present value of lease payments is determined by using the interest rate implicit in the lease, if that rate is readily determinable; otherwise, the Company uses its incremental borrowing rate. The incremental borrowing rate is determined by using the rate of interest that the Company would pay to borrow on a collateralized basis an amount equal to the lease payments for a similar term and in a similar economic environment. The Company’s leases have remaining terms of 1 year to 3.31 years, some of which include options to extend the lease term. The Company’s lease terms may include renewal options that are reasonably certain to be exercised and termination options that are reasonably certain not to be exercised. Certain finance leases also include bargain purchase options of the leased equipment.
Recent Accounting Pronouncements	Recent Accounting Pronouncements Effective January 1, 2019, the Company adopted ASC 842 using the optional transition method and applied the standard only to leases that existed at that date. Under the optional transition method, the Company does not need to restate the comparative periods in transition and will continue to present financial information and disclosures for periods before January 1, 2019 in accordance with ASC Topic 840. The Company has also chosen to apply the package of practical expedients for existing leases, which provides relief from reassessing: (i) whether a contract is or contains a lease, (ii) lease classification, and (iii) whether initial direct costs (IDCs) can be capitalized. The Company has also made some accounting policy elections to: (i) allow the Company not to separate nonlease components from lease components, and instead to account for those as a single lease component, and (ii) elect not to recognize a ROU asset and a lease liability for leases with a term of 12 months or less (“short-term leases”). Upon adoption of ASC 842 on January 1, 2019, the Company recorded a ROU asset of approximately $3.0 million and a lease liability of approximately $3.8 million. The lease liability was determined based on the present value of the remaining minimum lease payments. The ROU asset was determined based on the value of the lease liability, adjusted for the deferred rent balances of approximately $0.8 million, which were previously included in accrued and other liabilities as well as deferred rent, net of current portion. See Note 8 for further details. The standard did not have a material impact on the condensed consolidated statement of cash flows or the condensed consolidated statement of operations. In February 2018, the Financial Accounting Standards Board (“FASB”) issued ASU No. 2018-02, Income Statement – Reporting Comprehensive Income (ASC Topic 220): Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income . In June 2018, the FASB issued ASU No. 2018-07, Compensation - Stock Compensation (ASC Topic 718): Improvements to Nonemployee Share Based Payment Accounting In August 2018, the FASB issued ASU No. 2018-15, Intangibles – Goodwill and Other – Internal – Use Software (ASC Subtopic 350-40): Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract (“ASU 2018-15”). ASU 2018-15 is effective for fiscal years beginning after December 15, 2019 and interim periods therein. Early adoption of ASU 2018-15 is permitted including adoption in any interim period. The Company plans to adopt the standard during 2019. The Company expects the new standard will impact its prospective unaudited condensed consolidated financial statements after adoption related to implementation costs in a cloud computing arrangement if and when entered by the Company. In August 2018, the FASB issued ASU 2018-13, Fair Value Measurement (ASC Topic 820) In June 2016, the FASB issued ASU 2016-13, Measurement of Credit Losses on Financial Instruments (ASC Topic 326),

Net Loss Per Share (Tables)

Net Loss Per Share (Tables)	6 Months Ended
	Jun. 30, 2019
Earnings Per Share [Abstract]
Computation of Basic and Diluted Net Loss Per Share	The following tables set forth the computation of the Company’s basic and diluted net loss per share (in thousands, except shares and per share data): Three Months Ended June 30, Six Months Ended June 30, 2019 2018 2019 2018 Numerator: Net loss attributable to CareDx, Inc. used to compute basic and diluted net loss per share $ (7,847 ) $ (14,062 ) $ (15,378 ) $ (23,031 ) Denominator: Weighted-average shares used to compute basic and diluted net loss per share attributable to CareDx, Inc. 42,132,396 35,549,837 41,873,337 32,599,032 Net loss per share attributable to CareDx, Inc.: Basic and diluted $ (0.19 ) $ (0.40 ) $ (0.37 ) $ (0.71 )
Potentially Dilutive Securities Excluded from Diluted Net Loss Per Share	The following potentially dilutive securities have been excluded from diluted net loss per share as at June 30, 2019 because their effect would be antidilutive: Three and Six Months Ended June 30, 2019 2018 Shares of common stock subject to outstanding options 2,705,393 2,561,458 Shares of common stock subject to outstanding common stock warrants 466,695 3,328,089 Restricted stock units 1,292,440 896,904 Total common stock equivalents 4,464,528 6,786,451

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	6 Months Ended
	Jun. 30, 2019
Fair Value Disclosures [Abstract]
Fair Value of Financial Assets and Liabilities Measured on Recurring Basis	The following table sets forth the Company’s financial assets and liabilities measured at fair value on a recurring basis, as of June 30, 2019 and December 31, 2018 (in thousands): June 30, 2019 Fair Value Measured Using (Level 1) (Level 2) (Level 3) Total Balance Assets Money market funds $ 5,428 $ — $ — $ 5,428 Liabilities Common stock warrant liability $ — $ — $ 11,286 $ 11,286 December 31, 2018 Fair Value Measured Using (Level 1) (Level 2) (Level 3) Total Balance Assets Money market funds $ 59,471 $ — $ — $ 59,471 Liabilities Common stock warrant liability $ — $ — $ 10,003 $ 10,003
Summary of Issuances, Exercises, Changes in Fair Value and Reclassifications of Level 3 Financial Instruments	The following table presents the issuances, exercises, changes in fair value and reclassifications of the Company’s Level 3 financial instruments that are measured at fair value on a recurring basis (in thousands): (Level 3) Common Balance as of December 31, 2018 $ 10,003 Exercise of warrants (3,077 ) Change in estimated fair value 4,360 Balance as of June 30, 2019 $ 11,286
Summary of Common Stock Warrant Liability Valuation Assumptions	Common Stock Warrant Liability Valuation Assumptions June 30, 2019 December 31, 2018 Private Placement Common Stock Warrant Liability Stock Price $ 35.99 $ 25.14 Exercise Price $ 1.12 $ 1.12 Remaining term (in years) 3.79 4.29 Volatility 84.00 % 79.00 % Risk-free interest rate 1.71 % 2.46 %

Business Combinations (Tables)

Business Combinations (Tables)	6 Months Ended
	Jun. 30, 2019
Summary of Consideration Paid and Preliminary Amounts of Assets Acquired and Liabilities Assumed Recognized	The following table summarizes the fair values of the intangible assets acquired as of the closing date (in thousands): Estimated Fair Value Estimated Useful Lives (Years) Customer relationships: TruSight HLA $ 380 2.6 Acquired in-process technology: AlloSeq Tx 2,719 — Acquired in-process technology: AlloSeq HCT 2,103 — Total $ 5,202
Summary of Identified Intangible Assets Acquired at Acquisition Date	The following table summarizes the fair values of the intangible assets acquired as of the acquisition date (in thousands): Estimated Fair Value Estimated Useful Lives (Years) Customer relationships $ 4,200 15 Developed technology 2,300 10 Trademark 100 2 Total $ 6,600
OTTR Complete Transplant Management [Member]
Summary of Consideration Paid and Preliminary Amounts of Assets Acquired and Liabilities Assumed Recognized	The following table summarizes the consideration paid for OTTR and the provisional amounts of the assets acquired and liabilities assumed recognized at their estimated fair value at the acquisition date: Total (In Thousands) Consideration Cash $ 16,037 Accrued purchase consideration 111 Total Consideration $ 16,148 Recognized amounts of identifiable assets acquired and liabilities assumed Current assets $ 1,525 Fixed assets 35 Identifiable intangible assets 6,600 Current liabilities (2,566 ) Total identifiable net assets acquired 5,594 Goodwill 10,554 $ 16,148

Goodwill and Intangible Assets

Goodwill and Intangible Assets (Tables)	6 Months Ended
	Jun. 30, 2019
Goodwill And Intangible Assets Disclosure [Abstract]
Summary of Goodwill	Total Balance as of January 1, 2019 $ 12,005 Goodwill acquired 10,554 Balance as of June 30, 2019 $ 22,559
Summary of Intangible Assets	The following tables present details of the Company’s intangible assets as of June 30, 2019 (in thousands): June 30, 2019 Gross Carrying Amount Accumulated Amortization Foreign Currency Translation Net Amount Weighted Average Remaining Useful (In Intangible assets with finite lives: Customer relationships: Allenex $ 12,650 $ (2,573 ) $ (1,489 ) $ 8,588 11.5 Customer relationships: Conexio 28 (11 ) (2 ) 15 1.5 Customer relationships: TruSight HLA 380 (160 ) — 220 1.8 Developed technology: Olerup SSP 11,650 (3,588 ) (1,246 ) 6,816 6.5 Acquired technology: QTYPE 4,510 (809 ) (519 ) 3,182 11.5 Acquired technology: Olerup SBT 127 (51 ) (6 ) 70 1.5 Acquired technology: dd-cfDNA 6,650 (889 ) — 5,761 11.6 Trademarks 2,360 (529 ) (195 ) 1,636 6.7 Customer relationships: OTTR 4,200 (47 ) — 4,153 14.8 Developed technology: OTTR 2,300 (38 ) — 2,262 9.8 Commercialization rights of Cibiltech 8,079 — — 8,079 9.9 Total intangible assets with finite lives $ 52,934 $ (8,695 ) $ (3,457 ) $ 40,782 Acquired in-process technology: AlloSeq Tx 2,719 — — 2,719 — Acquired in-process technology: AlloSeq HCT 2,103 — — 2,103 — Total intangible assets $ 57,756 $ (8,695 ) $ (3,457 ) $ 45,604 The following table present details of the Company’s intangible assets as of December 31, 2018 (in thousands): December 31, 2018 Gross Carrying Amount Accumulated Amortization Foreign Currency Translation Net Amount Weighted Average Remaining Useful (In Intangible assets with finite lives: Customer relationships: Allenex $ 12,650 $ (2,198 ) $ (1,129 ) $ 9,323 12.0 Customer relationships: Conexio 28 (6 ) (2 ) 20 2.0 Customer relationships: TruSight HLA 380 (86 ) — 294 2.0 Developed technology: Olerup SSP 11,650 (3,065 ) (998 ) 7,587 7.0 Acquired technology: QTYPE 4,510 (671 ) (407 ) 3,432 12.0 Acquired technology: Olerup SBT 127 (28 ) (6 ) 93 2.0 Acquired technology: dd-cfDNA 6,650 (635 ) — 6,015 11.8 Trademarks 2,260 (454 ) (140 ) 1,666 12.0 Total intangible assets with finite lives $ 38,255 $ (7,143 ) $ (2,682 ) $ 28,430 Acquired in-process technology: AlloSeq Tx 2,719 — — 2,719 — Acquired in-process technology: AlloSeq HCT 2,103 — — 2,103 — Total intangible assets $ 43,077 $ (7,143 ) $ (2,682 ) $ 33,252
Summary of Consideration Paid and Preliminary Amounts of Assets Acquired and Liabilities Assumed Recognized	The following table summarizes the fair values of the intangible assets acquired as of the closing date (in thousands): Estimated Fair Value Estimated Useful Lives (Years) Customer relationships: TruSight HLA $ 380 2.6 Acquired in-process technology: AlloSeq Tx 2,719 — Acquired in-process technology: AlloSeq HCT 2,103 — Total $ 5,202
Summary of Estimated Future Amortization Expense of Intangible Assets	The following table summarizes the Company’s estimated future amortization expense of intangible assets with finite lives as of June 30, 2019 (in thousands): Years Ending December 31, Cost of Revenue Sales and Marketing Total Remainder of 2019 $ 1,392 $ 687 $ 2,079 2020 2,918 1,373 4,291 2021 2,871 1,183 4,054 2022 2,871 1,166 4,037 2023 2,871 1,166 4,037 Thereafter 13,245 9,039 22,284 Total future amortization expense $ 26,168 $ 14,614 $ 40,782

Balance Sheet Components (Table

Balance Sheet Components (Tables)	6 Months Ended
	Jun. 30, 2019
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Summary of Inventory	Inventory consisted of the following (in thousands): June 30, 2019 December 2018 Finished goods $ 2,519 $ 2,506 Work in progress 940 651 Raw materials 1,882 1,786 Total inventory $ 5,341 $ 4,943
Components of Accrued and Other Liabilities	Accrued and other liabilities consisted of the following (in thousands): June 30, 2019 December 2018 Deferred revenue $ 3,624 $ 39 Short-term lease liability 2,034 — Deferred payments for intangible assets 2,000 — Clinical studies 1,993 1,815 Test sample processing fees 782 657 Accrued royalty 696 285 Professional fees 596 822 Other accrued expenses 2,025 2,019 Total accrued and other liabilities $ 13,750 $ 5,637

Commitments (Tables)

Commitments (Tables)	6 Months Ended
	Jun. 30, 2019
Commitments And Contingencies Disclosure [Abstract]
Summary of Lease Cost	The following table summarizes the lease cost for the three and six months ended June 30, 2019 (in thousands): Three Months ended June 30, Six Months ended June 30, 2019 2019 Operating lease cost $ 455 $ 905 Finance lease cost 55 110 Total lease cost $ 510 $ 1,015 Other information: Weighted-average remaining lease term - Operating leases (in years) 1.7 Weighted-average remaining lease term - Finance leases (in years) 1.9 Weighted-average discount rate - Operating leases (%) 10.5 % Weighted-average discount rate - Finance leases (%) 6.5 %
Future Minimum Lease Commitments under Operating and Finance Leases	Future minimum lease commitments under these operating and finance leases as of June 30, 2019, are as follows (in thousands): Years Ending December 31, Finance Leases Operating Leases Remainder of 2019 $ 105 $ 1,140 2020 209 2,310 2021 71 223 2022 — 97 Total future minimum lease payments $ 385 $ 3,770

Warrants (Tables)

Warrants (Tables)	6 Months Ended
	Jun. 30, 2019
Common Stock [Member]
Class Of Warrant Or Right [Line Items]
Components of Warrants Outstanding	As of June 30, 2019, outstanding warrants to purchase common stock were: Classified as Original Term Exercise Price Number of Shares Underlying Warrants Original issue date: August 2012 Equity 7 years $ 21.78 111,455 January 2015 Equity 5 years $ 6.96 34,483 April 2016 Liability 7 years $ 1.12 320,757 466,695

Stock Incentive Plans (Tables)

Stock Incentive Plans (Tables)	6 Months Ended
	Jun. 30, 2019
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Summary of Option, Unvested RSU Activity under 2014 Equity Incentive Plan and 2016 Inducement Equity Incentive Plan and Related Information	The following table summarizes option and unvested RSU activity under the Company’s 2014 Equity Incentive Plan and 2016 Inducement Equity Incentive Plan and related information: Shares Available for Grant Stock Options Outstanding Weighted- Average Exercise Price Number of RSU Shares Weighted- Average Grant Date Fair Value Balance—December 31, 2018 322,178 2,501,057 $ 9.10 968,364 $ 11.49 Additional options authorized 1,655,398 — — — — Common stock awards for services (3,626 ) — — — — RSUs granted (856,965 ) — — 856,965 27.37 RSUs vested — — — (439,704 ) 13.14 Options granted (831,860 ) 831,860 28.11 — — Options exercised — (491,581 ) 5.64 — — Repurchase of common stock under employee incentive plans 133,913 — — — — RSUs forfeited 93,185 — — (93,185 ) 20.60 Options forfeited 134,504 (134,504 ) 11.76 — — Options expired 1,439 (1,439 ) 3.86 — — Balance—June 30, 2019 648,166 2,705,393 1,292,440
Summary of Options Outstanding and Exercisable Vested or Expected to Vest	Options outstanding that have vested and are expected to vest at June 30, 2019 are as follows: Number of Shares Weighted-Average Exercise Price Weighted-Average Remaining Contractual Life (Years) Aggregate Intrinsic (In Vested 903,539 $ 15.44 6.64 $ 26,697 Expected to vest 1,681,317 19.97 9.22 26,984 Total 2,584,856 $ 53,681
Weighted-Average Assumptions Used to Estimate Fair Values of Share-Based Awards	The estimated fair values of employee stock options and ESPP shares were estimated using the Black-Scholes option-pricing model based on the following weighted-average assumptions: Three Months Ended June 30, Six Months Ended June 30, 2019 2018 2019 2018 Employee stock options Expected term (in years) 6.0 6.0 6.0 6.0 Expected volatility 71.00 % 66.00 % 70.72 % 68.75 % Risk-free interest rate 2.34 % 2.76 % 2.43 % 2.71 % Expected dividend yield — % — % — % — % Employee stock purchase plan Expected term (in years) 0.50 0.5 0.50 0.5 Expected volatility 76.66 % 105.32 % 76.66 % 105.32 % Risk-free interest rate 2.51 % 1.61 % 2.51 % 1.61 % Expected dividend yield — % — % — % — %
Summary of Expense Relating to Employee and Nonemployee Stock-Based Payment Awards from Stock Options and RSUs	The following table summarizes stock-based compensation expense relating to employee and nonemployee stock-based awards for the three and six months ended June 30, 2019 and 2018, included in the condensed consolidated statements of operations as follows (in thousands): Three Months Ended June 30, Six Months Ended June 30, 2019 2018 2019 2018 Cost of revenue $ 508 $ 191 $ 1,280 $ 252 Research and development 1,441 462 2,273 675 Sales and marketing 940 466 1,671 529 General and administrative 2,103 1,393 5,821 1,761 Total $ 4,992 $ 2,512 $ 11,045 $ 3,217

Segment Reporting (Tables)

Segment Reporting (Tables)	6 Months Ended
	Jun. 30, 2019
Segment Reporting [Abstract]
Reportable Revenues by Geographic Regions	Revenues by geographic regions are based upon the customers’ ship-to address for product revenue and the region of testing for testing services revenue. The following table summarizes reportable revenues by geographic regions (in thousands): Three Six 2019 2018 2019 2018 Testing services revenue United States $ 25,499 $ 13,853 $ 46,885 $ 24,313 Rest of the World 178 144 310 288 $ 25,677 $ 13,997 $ 47,195 $ 24,601 Product revenue United States $ 2,168 $ 1,319 $ 4,000 $ 2,164 Europe 1,906 1,688 3,849 3,661 Rest of the World 519 543 1,177 1,032 $ 4,593 $ 3,550 $ 9,026 $ 6,857 Digital and other revenue United States $ 1,108 $ 235 $ 1,130 $ 377 Europe 50 41 60 41 Rest of the World 26 — 25 — $ 1,184 $ 276 $ 1,215 $ 418 Total United States $ 28,775 $ 15,407 $ 52,015 $ 26,854 Total Europe $ 1,956 $ 1,729 $ 3,909 $ 3,702 Total Rest of the World $ 723 $ 687 $ 1,512 $ 1,320 Total $ 31,454 $ 17,823 $ 57,436 $ 31,876
Long-Lived Assets Consisting of Property and Equipment, Net by Geographic Regions	The following table summarizes long-lived assets, consisting of property and equipment, net, by geographic regions (in thousands): June 30, 2019 December Long-lived assets: United States $ 2,712 $ 3,235 Europe 498 625 Rest of the World 298 274 Total $ 3,508 $ 4,134

Organization and Description _3

Organization and Description of Business - Additional Information (Detail)	May 07, 2019	Jun. 30, 2019USD ($)	Jun. 30, 2019USD ($)	Jun. 30, 2018USD ($)	Jun. 30, 2019USD ($)Center	Jun. 30, 2018USD ($)	Dec. 31, 2018USD ($)
Schedule of Capitalization, Equity [Line Items]
Total revenue			$ 31,454,000	$ 17,823,000	$ 57,436,000	$ 31,876,000
Accumulated deficit		$ 327,223,000	327,223,000		327,223,000		$ 311,845,000
Cash and cash equivalents		43,469,000	43,469,000		43,469,000		64,616,000
Digital and Other [Member]
Schedule of Capitalization, Equity [Line Items]
Total revenue			$ 1,184,000	$ 276,000	1,215,000	$ 418,000
Medicare [Member] | AlloMap Testing Service [Member]
Schedule of Capitalization, Equity [Line Items]
Reimbursement rate					3,240		$ 3,240
Medicare [Member] | AlloSure Testing Service [Member]
Schedule of Capitalization, Equity [Line Items]
Reimbursement rate					$ 2,841
OTTR Complete Transplant Management [Member]
Schedule of Capitalization, Equity [Line Items]
Percentage of outstanding equity to be acquired	100.00%
Acquisition, closing date	May 7, 2019				May 7, 2019
Number of leading transplant centers | Center					60
OTTR Complete Transplant Management [Member] | Digital and Other [Member]
Schedule of Capitalization, Equity [Line Items]
Total revenue		$ 1,100,000			$ 1,100,000

Summary of Significant Accoun_2

Summary of Significant Accounting Policies - Additional Information - Concentration of Credit Risk (Detail)	6 Months Ended		12 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Services Revenue [Member] | Customer Concentration Risk [Member] | Minimum [Member]
Concentration Risk [Line Items]
Concentration risk, percentage	10.00%	10.00%
Services Revenue [Member] | Customer Concentration Risk [Member] | Medicare [Member]
Concentration Risk [Line Items]
Concentration risk, percentage	54.00%	45.00%
Accounts Receivable [Member] | Credit Concentration Risk [Member] | Minimum [Member]
Concentration Risk [Line Items]
Concentration risk, percentage	10.00%		10.00%
Accounts Receivable [Member] | Credit Concentration Risk [Member] | Medicare [Member]
Concentration Risk [Line Items]
Concentration risk, percentage	27.00%		27.00%

Summary of Significant Accoun_3

Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2019	Jan. 01, 2019	Dec. 31, 2018
Summary Of Significant Accounting Policies [Line Items]
Operating lease, right-of-use asset	$ 2,657		$ 0
ASU 2016-02 [Member]
Summary Of Significant Accounting Policies [Line Items]
Operating lease, right-of-use asset		$ 3,000
Operating lease, liability		3,800
Deferred rent		$ 800
Minimum [Member]
Summary Of Significant Accounting Policies [Line Items]
Remaining operating and finance lease term lower limit	1 year
Maximum [Member]
Summary Of Significant Accounting Policies [Line Items]
Remaining lease term	3 years 3 months 21 days

Net Loss Per Share - Computatio

Net Loss Per Share - Computation of Basic and Diluted Net Loss Per Share (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Numerator:
Net loss attributable to CareDx, Inc. used to compute basic and diluted net loss per share	$ (7,847)	$ (14,062)	$ (15,378)	$ (23,031)
Denominator:
Weighted-average shares used to compute basic and diluted net loss per share attributable to CareDx, Inc.	42,132,396	35,549,837	41,873,337	32,599,032
Net loss per share attributable to CareDx, Inc.:
Basic and diluted	$ (0.19)	$ (0.40)	$ (0.37)	$ (0.71)

Net Loss Per Share - Potentiall

Net Loss Per Share - Potentially Dilutive Securities Excluded from Diluted Net Loss Per Share (Detail) - shares	3 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potential dilutive securities excluded from diluted net loss per share attributable to common stockholders, Total	4,464,528	6,786,451
Shares of common stock subject to outstanding options [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potential dilutive securities excluded from diluted net loss per share attributable to common stockholders, Total	2,705,393	2,561,458
Shares of common stock subject to outstanding common stock warrants [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potential dilutive securities excluded from diluted net loss per share attributable to common stockholders, Total	466,695	3,328,089
Restricted Stock Units (RSUs) [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potential dilutive securities excluded from diluted net loss per share attributable to common stockholders, Total	1,292,440	896,904

Fair Value Measurements - Fair

Fair Value Measurements - Fair Value of Financial Assets and Liabilities Measured on Recurring Basis (Detail) - Recurring [Member] - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Assets
Money market funds	$ 5,428	$ 59,471
Liabilities
Common stock warrant liability	11,286	10,003
Fair Value Measured Using - (Level 1) [Member]
Assets
Money market funds	5,428	59,471
Liabilities
Common stock warrant liability	0	0
Fair Value Measured Using - (Level 2) [Member]
Assets
Money market funds	0	0
Liabilities
Common stock warrant liability	0	0
Fair Value Measured Using - (Level 3) [Member]
Assets
Money market funds	0	0
Liabilities
Common stock warrant liability	$ 11,286	$ 10,003

Fair Value Measurements - Summa

Fair Value Measurements - Summary of Issuances, Exercises, Changes in Fair Value and Reclassifications of Level 3 Financial Instruments (Detail) - Fair Value Measured Using - (Level 3) [Member] - Common Stock Warrant Liability [Member] $ in Thousands	6 Months Ended
	Jun. 30, 2019USD ($)
Significant Unobservable Inputs (Level 3) [Line Items]
Beginning Balance	$ 10,003
Exercise of warrants	(3,077)
Change in estimated fair value	4,360
Ending Balance	$ 11,286

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Detail) - USD ($)	6 Months Ended	12 Months Ended
	Jun. 30, 2019	Dec. 31, 2018
Fair Value Disclosures [Abstract]
Transfers between Level 1, Level 2 and Level 3 categories during the periods	$ 0	$ 0

Fair Value Measurements - Sum_2

Fair Value Measurements - Summary of Common Stock Warrant Liability Valuation Assumptions (Detail) - Private Placement Common Stock Warrant Liability [Member]	6 Months Ended	12 Months Ended
	Jun. 30, 2019$ / shares	Dec. 31, 2018$ / shares
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Stock Price	$ 35.99	$ 25.14
Exercise Price [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Exercise Price	$ 1.12	$ 1.12
Remaining Term (in Years) [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Remaining term (in years)	3 years 9 months 14 days	4 years 3 months 14 days
Volatility [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Derivative liability, measurement input	84	79
Risk-Free Interest Rate [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Derivative liability, measurement input	1.71	2.46

Business Combinations - Additio

Business Combinations - Additional Information (Detail)	May 07, 2019USD ($)Center	Jun. 30, 2019USD ($)	Jun. 30, 2019USD ($)	Mar. 31, 2019USD ($)	Jun. 30, 2018USD ($)	Mar. 31, 2018USD ($)	Jun. 30, 2019USD ($)Center	Jun. 30, 2018USD ($)	Dec. 31, 2018USD ($)
Business Acquisition [Line Items]
Goodwill		$ 22,559,000	$ 22,559,000				$ 22,559,000		$ 12,005,000
Net deferred tax assets related to assets acquired and liabilities assumed	$ 200,000
Valuation allowance	$ 200,000
Revenue			31,454,000		$ 17,823,000		57,436,000	$ 31,876,000
Net loss			(7,847,000)	$ (7,531,000)	(14,062,000)	$ (8,994,000)	(15,378,000)	(23,056,000)
Digital and Other [Member]
Business Acquisition [Line Items]
Revenue			$ 1,184,000		$ 276,000		$ 1,215,000	$ 418,000
Royalty Rate [Member] | Developed Technology [Member]
Business Acquisition [Line Items]
Rate used in estimating fair value	15
Royalty Rate [Member] | Trademarks [Member]
Business Acquisition [Line Items]
Rate used in estimating fair value	1
Discount Rate [Member]
Business Acquisition [Line Items]
Rate used in estimating fair value	14.5
OTTR Complete Transplant Management [Member]
Business Acquisition [Line Items]
Acquisition, closing date	May 7, 2019						May 7, 2019
Percentage of outstanding equity to be acquired	100.00%
Total consideration	$ 16,148,000
Number of leading transplant centers | Center							60
Goodwill	10,554,000
Goodwill expected to be deductible for income tax purposes	0
Deferred revenue	2,300,000
Net operating losses carryforward	6,900,000
Net operating losses carryforward expires in future	4,300,000
Operating loss carry forwards with indefinite carry forward period	$ 2,600,000
Operating loss carryforwards, expiration year	2033
Net loss							$ 100,000
OTTR Complete Transplant Management [Member] | Digital and Other [Member]
Business Acquisition [Line Items]
Revenue		$ 1,100,000					$ 1,100,000
OTTR Complete Transplant Management [Member] | General and Administrative Expenses [Member]
Business Acquisition [Line Items]
Acquisition related costs	$ 600,000
OTTR Complete Transplant Management [Member] | Minimum [Member]
Business Acquisition [Line Items]
Number of leading transplant centers | Center	60

Business Combinations - Summary

Business Combinations - Summary of Consideration Paid and Provisional Amounts of Assets Acquired and Liabilities Assumed Recognized at Their Estimated Fair Value (Detail) - USD ($) $ in Thousands	May 07, 2019	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Business Acquisition [Line Items]
Cash		$ 16,037	$ 0
Goodwill		$ 22,559		$ 12,005
OTTR Complete Transplant Management [Member]
Business Acquisition [Line Items]
Cash	$ 16,037
Accrued purchase consideration	111
Total Consideration	16,148
Current assets	1,525
Fixed assets	35
Identifiable intangible assets	6,600
Current liabilities	(2,566)
Total identifiable net assets acquired	5,594
Goodwill	10,554
Total Consideration	$ 16,148

Business Combinations - Summa_2

Business Combinations - Summary of Identified Intangible Assets Acquired at Acquisition Date (Detail) - USD ($) $ in Thousands	May 07, 2019	Jun. 30, 2019	Dec. 31, 2018
Business Acquisition [Line Items]
Estimated fair value of identified intangible assets	$ 6,600
Customer Relationships [Member]
Business Acquisition [Line Items]
Estimated fair value of identified intangible assets	$ 4,200
Estimated useful life of identified intangible asset	15 years
Developed Technology [Member]
Business Acquisition [Line Items]
Estimated fair value of identified intangible assets	$ 2,300
Estimated useful life of identified intangible asset	10 years	6 years 6 months	7 years
Trademarks [Member]
Business Acquisition [Line Items]
Estimated fair value of identified intangible assets	$ 100
Estimated useful life of identified intangible asset	2 years	6 years 8 months 12 days	12 years

Goodwill and Intangible Asset_2

Goodwill and Intangible Assets - Summary of Goodwill (Detail) $ in Thousands	6 Months Ended
	Jun. 30, 2019USD ($)
Goodwill And Intangible Assets Disclosure [Abstract]
Balance as of January 1, 2019	$ 12,005
Goodwill acquired	10,554
Balance as of June 30, 2019	$ 22,559

Goodwill and Intangible Asset_3

Goodwill and Intangible Assets - Summary of Intangible Assets (Detail) - USD ($) $ in Thousands	May 07, 2019	May 04, 2018	Jun. 30, 2019	Dec. 31, 2018
Intangible assets with finite lives:
Gross Carrying Amount			$ 52,934	$ 38,255
Accumulated Amortization			(8,695)	(7,143)
Foreign Currency Translation			(3,457)	(2,682)
Net Carrying Amount			40,782	28,430
Intangible Assets, Net (Excluding Goodwill)
Total intangible assets, Gross Carrying Amount			57,756	43,077
Total intangible assets, Accumulated Amortization			(8,695)	(7,143)
Total intangible assets, Foreign Currency Translation			(3,457)	(2,682)
Total intangible assets, net			45,604	33,252
Customer Relationships [Member]
Intangible assets with finite lives:
Estimated useful life of identified intangible asset	15 years
Customer Relationships [Member] | OTTR [Member]
Intangible assets with finite lives:
Gross Carrying Amount			4,200
Accumulated Amortization			(47)
Foreign Currency Translation			0
Net Carrying Amount			$ 4,153
Estimated useful life of identified intangible asset			14 years 9 months 18 days
Customer Relationships [Member] | Allenex [Member]
Intangible assets with finite lives:
Gross Carrying Amount			$ 12,650	12,650
Accumulated Amortization			(2,573)	(2,198)
Foreign Currency Translation			(1,489)	(1,129)
Net Carrying Amount			$ 8,588	$ 9,323
Estimated useful life of identified intangible asset			11 years 6 months	12 years
Customer Relationships [Member] | Conexio [Member]
Intangible assets with finite lives:
Gross Carrying Amount			$ 28	$ 28
Accumulated Amortization			(11)	(6)
Foreign Currency Translation			(2)	(2)
Net Carrying Amount			$ 15	$ 20
Estimated useful life of identified intangible asset			1 year 6 months	2 years
Customer Relationships [Member] | TruSight [Member]
Intangible assets with finite lives:
Gross Carrying Amount			$ 380	$ 380
Accumulated Amortization			(160)	(86)
Foreign Currency Translation			0	0
Net Carrying Amount			$ 220	$ 294
Estimated useful life of identified intangible asset		2 years 7 months 6 days	1 year 9 months 18 days	2 years
Developed Technology [Member]
Intangible assets with finite lives:
Gross Carrying Amount			$ 11,650	$ 11,650
Accumulated Amortization			(3,588)	(3,065)
Foreign Currency Translation			(1,246)	(998)
Net Carrying Amount			$ 6,816	$ 7,587
Estimated useful life of identified intangible asset	10 years		6 years 6 months	7 years
Developed Technology [Member] | OTTR [Member]
Intangible assets with finite lives:
Gross Carrying Amount			$ 2,300
Accumulated Amortization			(38)
Net Carrying Amount			$ 2,262
Estimated useful life of identified intangible asset			9 years 9 months 18 days
Acquired Technology - QTYPE [Member]
Intangible assets with finite lives:
Gross Carrying Amount			$ 4,510	$ 4,510
Accumulated Amortization			(809)	(671)
Foreign Currency Translation			(519)	(407)
Net Carrying Amount			$ 3,182	$ 3,432
Estimated useful life of identified intangible asset			11 years 6 months	12 years
Acquired Technology SBT [Member] | Olerup [Member]
Intangible assets with finite lives:
Gross Carrying Amount			$ 127	$ 127
Accumulated Amortization			(51)	(28)
Foreign Currency Translation			(6)	(6)
Net Carrying Amount			$ 70	$ 93
Estimated useful life of identified intangible asset			1 year 6 months	2 years
Acquired Technology dd-cfDNA [Member]
Intangible assets with finite lives:
Gross Carrying Amount			$ 6,650	$ 6,650
Accumulated Amortization			(889)	(635)
Foreign Currency Translation			0	0
Net Carrying Amount			$ 5,761	$ 6,015
Estimated useful life of identified intangible asset			11 years 7 months 6 days	11 years 9 months 18 days
Trademarks [Member]
Intangible assets with finite lives:
Gross Carrying Amount			$ 2,360	$ 2,260
Accumulated Amortization			(529)	(454)
Foreign Currency Translation			(195)	(140)
Net Carrying Amount			$ 1,636	$ 1,666
Estimated useful life of identified intangible asset	2 years		6 years 8 months 12 days	12 years
Commercialization Rights of Cibiltech [Member]
Intangible assets with finite lives:
Gross Carrying Amount			$ 8,079
Accumulated Amortization			0
Foreign Currency Translation			0
Net Carrying Amount			$ 8,079
Estimated useful life of identified intangible asset			9 years 10 months 24 days
Acquired in-process technology AlloSeq [Member] | Tx [Member]
Intangible assets with indefinite lives:
Foreign Currency Translation			$ 0	$ 0
Net Carrying Amount			2,719	2,719
Acquired in-process technology AlloSeq [Member] | HCT [Member]
Intangible assets with indefinite lives:
Foreign Currency Translation			0	0
Net Carrying Amount			$ 2,103	$ 2,103

Goodwill and Intangible Asset_4

Goodwill and Intangible Assets - Additional Information (Detail) $ in Thousands	Apr. 30, 2019	May 04, 2018USD ($)	Jun. 30, 2019USD ($)	Jun. 30, 2018USD ($)	Jun. 30, 2019USD ($)	Jun. 30, 2018USD ($)	Jul. 26, 2019USD ($)	May 07, 2019
Goodwill And Intangible Assets [Line Items]
Consideration paid for asset acquisition					$ 1,124	$ 5,202
Amortization expense of intangible assets			$ 700	$ 600	1,300	1,200
Cost of Product [Member]
Goodwill And Intangible Assets [Line Items]
Amortization expense of intangible assets			400	400	700	700
Sales and Marketing Expense [Member]
Goodwill And Intangible Assets [Line Items]
Amortization expense of intangible assets			$ 300	$ 200	$ 600	$ 500
Cibiltech Agreement [Member] | Cibiltech [Member]
Goodwill And Intangible Assets [Line Items]
Commercialization rights of intangible assets term	10 years
Cibiltech Agreement [Member] | Cibiltech [Member] | Subsequent Event [Member] | Convertible Preferred Shares [Member]
Goodwill And Intangible Assets [Line Items]
Purchases under license and commercialization agreement							$ 1,000
Discount Rate [Member]
Goodwill And Intangible Assets [Line Items]
Rate used in estimating fair value								14.5
Discount Rate [Member] | Customer Relationships [Member]
Goodwill And Intangible Assets [Line Items]
Rate used in estimating fair value		18
Discount Rate [Member] | Commercialization Rights [Member] | Cibiltech Agreement [Member] | Cibiltech [Member]
Goodwill And Intangible Assets [Line Items]
Rate used in estimating fair value	0.06
Illumina [Member]
Goodwill And Intangible Assets [Line Items]
Initial cash payment under license agreement		$ 5,000
Consideration paid for asset acquisition		5,200
Asset acquisition cash consideration transferred		5,000
Transaction costs related to asset acquisition		$ 200
Illumina [Member] | Discount Rate [Member] | Acquired in-process technology AlloSeq [Member] | Tx [Member]
Goodwill And Intangible Assets [Line Items]
Rate used in estimating fair value		30
Illumina [Member] | Discount Rate [Member] | Acquired in-process technology AlloSeq [Member] | BMT [Member]
Goodwill And Intangible Assets [Line Items]
Rate used in estimating fair value		40

Goodwill and Intangible Asset_5

Goodwill and Intangible Assets - Summary of Fair Values of Assets Acquired and Liabilities Assumed as of Acquisition Date (Detail) - USD ($) $ in Thousands	May 07, 2019	May 04, 2018	Jun. 30, 2019	Dec. 31, 2018
Goodwill And Intangible Assets [Line Items]
Estimated fair value of identified intangible assets	$ 6,600
Customer Relationships [Member]
Goodwill And Intangible Assets [Line Items]
Estimated fair value of identified intangible assets	$ 4,200
Estimated useful life of identified intangible asset	15 years
Customer Relationships [Member] | TruSight [Member]
Goodwill And Intangible Assets [Line Items]
Estimated useful life of identified intangible asset		2 years 7 months 6 days	1 year 9 months 18 days	2 years
Customer Relationships [Member] | TruSight [Member] | HLA [Member]
Goodwill And Intangible Assets [Line Items]
Estimated fair value of identified intangible assets		$ 380
Illumina [Member]
Goodwill And Intangible Assets [Line Items]
Estimated fair value of identified intangible assets		5,202
Illumina [Member] | Acquired in-process technology AlloSeq [Member] | Tx [Member]
Goodwill And Intangible Assets [Line Items]
Estimated fair value of identified intangible assets		2,719
Illumina [Member] | Acquired in-process technology AlloSeq [Member] | HCT [Member]
Goodwill And Intangible Assets [Line Items]
Estimated fair value of identified intangible assets		$ 2,103

Goodwill and Intangible Asset_6

Goodwill and Intangible Assets - Summary of Estimated Future Amortization Expense of Intangible Assets with Finite Lives (Detail) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
Remainder of 2019	$ 2,079
2020	4,291
2021	4,054
2022	4,037
2023	4,037
Thereafter	22,284
Net Carrying Amount	40,782	$ 28,430
Cost of Revenue [Member]
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
Remainder of 2019	1,392
2020	2,918
2021	2,871
2022	2,871
2023	2,871
Thereafter	13,245
Net Carrying Amount	26,168
Sales and marketing [Member]
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
Remainder of 2019	687
2020	1,373
2021	1,183
2022	1,166
2023	1,166
Thereafter	9,039
Net Carrying Amount	$ 14,614

Balance Sheet Components - Summ

Balance Sheet Components - Summary of Inventory (Detail) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Inventory Disclosure [Abstract]
Finished goods	$ 2,519	$ 2,506
Work in progress	940	651
Raw materials	1,882	1,786
Total inventory	$ 5,341	$ 4,943

Balance Sheet Components - Comp

Balance Sheet Components - Components of Accrued Expenses and Other Current Liabilities (Detail) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Payables And Accruals [Abstract]
Deferred revenue	$ 3,624	$ 39
Short-term lease liability	2,034	0
Deferred payments for intangible assets	2,000	0
Clinical studies	1,993	1,815
Test sample processing fees	782	657
Accrued royalty	696	285
Professional fees	596	822
Other accrued expenses	2,025	2,019
Total accrued and other liabilities	$ 13,750	$ 5,637

Commitments - Additional Inform

Commitments - Additional Information (Detail) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Loss Contingencies [Line Items]
Facility leases expiration period			2022
Rent expense under non-cancelable operating leases	$ 500,000	$ 400,000	$ 900,000	$ 900,000
Royalties incurred	300,000		400,000
Illumina [Member]
Loss Contingencies [Line Items]
Royalties incurred	$ 0		$ 0

Commitments - Summary of Lease

Commitments - Summary of Lease Cost (Detail) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2019
Commitments And Contingencies Disclosure [Abstract]
Operating lease cost	$ 455	$ 905
Finance lease cost	55	110
Total lease cost	$ 510	$ 1,015

Commitments - Summary of Other

Commitments - Summary of Other Information Related to Lease (Detail)	Jun. 30, 2019
Other information:
Weighted-average remaining lease term - Operating leases (in years)	1 year 8 months 12 days
Weighted-average remaining lease term - Finance leases (in years)	1 year 10 months 24 days
Weighted-average discount rate - Operating leases (%)	10.50%
Weighted-average discount rate - Finance leases (%)	6.50%

Commitments - Future Minimum Le

Commitments - Future Minimum Lease Commitments under Operating and Finance Leases (Detail) $ in Thousands	Jun. 30, 2019USD ($)
Finance Leases
Remainder of 2019	$ 105
2020	209
2021	71
2022	0
Total future minimum lease payments	385
Operating Leases
Remainder of 2019	1,140
2020	2,310
2021	223
2022	97
Total future minimum lease payments	$ 3,770

Debt - Additional Information (

Debt - Additional Information (Detail)

Nov. 20, 2018USD ($)

Apr. 17, 2018USD ($)

Apr. 17, 2018SEK (kr)

Feb. 26, 2018USD ($)

Feb. 26, 2018SEK (kr)

Mar. 31, 2018USD ($)shares

Jun. 30, 2019USD ($)

Jun. 30, 2018USD ($)

Mar. 31, 2018USD ($)

Jun. 30, 2019USD ($)

Jun. 30, 2018USD ($)

Dec. 31, 2018USD ($)

Debt Instrument [Line Items]

Current portion of long-term debt

$ 0

$ 0

$ 0

Long-term debt, net of current portion

0

0

$ 0

Loss on debt extinguishment

$ 0

$ 0

0

$ 2,806,000

Amount recognized to additional paid in capital

$ 38,854,000

Loss on debt extinguishment

$ 0

$ 2,806,000

Danske Term Loan and Credit Facility [Member]

Debt Instrument [Line Items]

Repayment of accrued interest

$ 17,000

kr 142,000

Danske Bank A S [Member] | Danske Term Loan and Credit Facility [Member]

Debt Instrument [Line Items]

Repayment of outstanding debt

5,600,000

47,000,000

S S P Primers Aktieboulag | Allenex [Member]

Debt Instrument [Line Items]

Repayment of outstanding debt

$ 1,200,000

kr 10,000,000

Repayment of accrued interest

$ 100,000

kr 650,000

Common Stock [Member]

Debt Instrument [Line Items]

Amount recognized to additional paid in capital

6,000

Perceptive Credit Agreement [Member]

Debt Instrument [Line Items]

Aggregate principal amount

15,000,000

Perceptive Credit Agreement [Member] | Other Income (Expense) [Member]

Debt Instrument [Line Items]

Loss on debt extinguishment

$ (3,000,000)

JGB Debt [Member]

Debt Instrument [Line Items]

Debentures convertible into common stock, outstanding principal amount

$ 26,700,000

Debentures convertible into common stock | shares

6,161,331

Amount recognized to additional paid in capital

38,800,000

Extinguishment of unamortized debt discount

2,700,000

Extinguishment of compound derivative liability

12,100,000

JGB Debt [Member] | Common Stock [Member]

Debt Instrument [Line Items]

Debentures convertible into common stock, outstanding principal amount

6,000

JGB Debt [Member] | Other Income (Expense) [Member]

Debt Instrument [Line Items]

Loss on debt extinguishment

$ 2,800,000

Subordinated Promissory Note [Member]

Debt Instrument [Line Items]

Repayment of outstanding debt

2,500,000

21,300,000

Repayment of accrued interest

200,000

1,600,000

Subordinated Promissory Note [Member] | Mohammed Al Amoudi [Member] | Allenex [Member]

Debt Instrument [Line Items]

Repayment of outstanding debt

1,900,000

15,700,000

Repayment of accrued interest

$ 100,000

kr 1,200,000

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Detail) $ / shares in Units, $ in Millions	Nov. 16, 2018USD ($)$ / sharesshares	May 22, 2018CommercialTestshares	Jun. 30, 2014shares	Jun. 30, 2018shares	Jun. 30, 2019CommercialTest
Common Stock [Member]
Class Of Stock [Line Items]
Number of shares issued pursuant to contingent consideration				227,848
Common Stock [Member] | 2018 Public Offering [Member]
Class Of Stock [Line Items]
Common stock shares issued	2,300,000
Common stock offer price per share | $ / shares	$ 24.50
Option to purchase additional shares	300,000
Net proceeds from common stock shares issued at public offering | $	$ 52.9
ImmuMetrix, Inc. [Member]
Class Of Stock [Line Items]
Issuable common stock under contingent obligation			227,845
Number of shares issued pursuant to contingent consideration		227,848
Milestone description					The shares were issuable upon the Company completing 2,500 commercial tests involving the measurement of dd-cfDNA in organ transplant recipients in the United States by June 10, 2020.
Commercial test, measurement and completion date					Jun. 10, 2020
Number of commercial tests involving the measurement of cfDNA to be completed | CommercialTest					2,500
Number of achieved contingent consideration milestone of commercial tests involving the measurement of cfDNA | CommercialTest		2,500

401(K) Plan - Additional Inform

401(K) Plan - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Compensation And Retirement Disclosure [Abstract]
Expense incurred related to plan	$ 0.1	$ 0.1	$ 0.3	$ 0.1

Warrants - Additional Informati

Warrants - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Class Of Warrant Or Right [Line Items]
Purchase of common stock warrants exercised	24,000	445,000	94,000	468,000
Proceeds from exercise of warrants		$ 500	$ 105	$ 524
Exercise of warrants	40,000		96,000
Shares issued	15,000		40,000
Maximum [Member]
Class Of Warrant Or Right [Line Items]
Proceeds from exercise of warrants	$ 100

Warrants - Outstanding Warrants

Warrants - Outstanding Warrants To Purchase Common Stock Warrants (Detail) - Common Stock [Member]	6 Months Ended
	Jun. 30, 2019$ / sharesshares
Class Of Warrant Or Right [Line Items]
Number of Shares Underlying Warrants	466,695
Class Of Warrant Or Right Issued on August 2012 [Member]
Class Of Warrant Or Right [Line Items]
Issue Date	2012-08
Classified as	Equity
Exercise Price | $ / shares	$ 21.78
Number of Shares Underlying Warrants	111,455
Class Of Warrant Or Right Issued on August 2012 [Member] | Remaining Term (in Years) [Member]
Class Of Warrant Or Right [Line Items]
Original Term	7 years
Class Of Warrant Or Right Issued on January 2015 [Member]
Class Of Warrant Or Right [Line Items]
Issue Date	2015-01
Classified as	Equity
Exercise Price | $ / shares	$ 6.96
Number of Shares Underlying Warrants	34,483
Class Of Warrant Or Right Issued on January 2015 [Member] | Remaining Term (in Years) [Member]
Class Of Warrant Or Right [Line Items]
Original Term	5 years
Class Of Warrant Or Right Issued on April 2016 [Member]
Class Of Warrant Or Right [Line Items]
Issue Date	2016-04
Classified as	Liability
Exercise Price | $ / shares	$ 1.12
Number of Shares Underlying Warrants	320,757
Class Of Warrant Or Right Issued on April 2016 [Member] | Remaining Term (in Years) [Member]
Class Of Warrant Or Right [Line Items]
Original Term	7 years

Stock Incentive Plans - Summary

Stock Incentive Plans - Summary of Option, Unvested RSU Activity under 2014 Equity Incentive Plan and 2016 Inducement Equity Incentive Plan and Related Information (Detail)	6 Months Ended
	Jun. 30, 2019$ / sharesshares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares Available for Grant, Beginning Balance	322,178
Shares Available for Grant, Additional options authorized	1,655,398
Shares Available for Grant, Common stock awards for services	(3,626)
Shares Available for Grant, Options granted	(831,860)
Shares Available for Grant, Options exercised	0
Shares Available for Grant, Repurchases of common stock under employee incentive plans	133,913
Shares Available for Grant, RSUs forfeited	93,185
Shares Available for Grant, Options forfeited	134,504
Shares Available for Grant, Options expired	1,439
Shares Available for Grant, Ending Balance	648,166
Number of Shares, Beginning Balance	2,501,057
Number of Shares, Additional options authorized	0
Number of Shares, Options granted	831,860
Number of Shares, Options exercised	(491,581)
Number of Shares, Options forfeited	(134,504)
Number of Shares, Options expired	(1,439)
Number of Shares, Ending Balance	2,705,393
Weighted-Average Exercise Price, Beginning Balance | $ / shares	$ 9.10
Weighted-Average Exercise Price, Additional options authorized | $ / shares	0
Weighted-Average Exercise Price, Options granted | $ / shares	28.11
Weighted-Average Exercise Price, Options exercised | $ / shares	5.64
Weighted-Average Exercise Price, Options forfeited | $ / shares	11.76
Weighted-Average Exercise Price, Options expired | $ / shares	3.86
Weighted-Average Exercise Price, Ending Balance | $ / shares	$ 0
Number of RSU Shares, forfeited	(93,185)
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares Available for Grant	(856,965)
Number of RSU Shares, vested	(439,704)
Shares Available for Grant, RSUs forfeited	93,185
Number of RSU Shares, Beginning Balance	968,364
Shares Available for Grant	856,965
Number of RSU Shares, forfeited	(93,185)
Number of RSU Shares, Ending Balance	1,292,440
Weighted Average Grant- Date Fair Value, Unvested beginning balance | $ / shares	$ 11.49
Weighted- Average Grant Date Fair Value, RSUs granted | $ / shares	27.37
Weighted- Average Grant Date Fair Value, RSUs vested | $ / shares	13.14
Weighted- Average Grant Date Fair Value, RSUs forfeited | $ / shares	20.60
Weighted Average Grant- Date Fair Value, Unvested ending balance | $ / shares	$ 0

Stock Incentive Plans - Additio

Stock Incentive Plans - Additional Information (Detail) - USD ($)	3 Months Ended	6 Months Ended	12 Months Ended
	Jun. 30, 2019	Jun. 30, 2019	Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total intrinsic value of options exercised	$ 6,000,000	$ 12,000,000
Share-based compensation expense, tax benefit recognized		0
Share-based compensation expense, capitalized		$ 0
2014 Employee Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum portion of earning an employee may contribute to the ESPP Plan	15.00%	15.00%
Maximum value of shares which an employee can purchase per calendar year		$ 25,000
Applicable exercise date an offering period shall be equal to percentage of the lower of fair market value of common stock		85.00%
Offering period for employee stock purchases		6 months
Aggregate proceeds from the issuance of shares		$ 400,000	$ 300,000
Shares issued under ESPP		20,528	31,184
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Intrinsic value of RSUs	$ 46,500,000	$ 46,500,000
Total unrecognized compensation costs related to stock options and RSUs	22,600,000	$ 22,600,000
Stock options and RSUs expected weighted average period		2 years 11 months 8 days
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options and RSUs expected weighted average period		3 years 5 months 1 day
Total unrecognized compensation costs related to stock options	19,300,000	$ 19,300,000
Total fair value of options vested during period	$ 1,200,000	$ 1,700,000

Stock Incentive Plans - Summa_2

Stock Incentive Plans - Summary of Options Outstanding Vested and Expected to Vest (Detail) $ / shares in Units, $ in Thousands	6 Months Ended
	Jun. 30, 2019USD ($)$ / sharesshares
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Number of Shares, Vested | shares	903,539
Number of Shares, Expected to vest | shares	1,681,317
Number of Shares, Total | shares	2,584,856
Weighted-average Exercise Price, Vested | $ / shares	$ 15.44
Weighted-average Exercise Price, Expected to vest | $ / shares	$ 19.97
Weighted-average Remaining Contractual Life (Years), Vested	6 years 7 months 20 days
Weighted-average Remaining Contractual Life (Years), Expected to vest	9 years 2 months 19 days
Aggregate Intrinsic Value, Vested | $	$ 26,697
Aggregate Intrinsic Value, Expected to vest | $	26,984
Aggregate Intrinsic Value, Total | $	$ 53,681

Stock Incentive Plans - Weighte

Stock Incentive Plans - Weighted-Average Assumptions Used to Estimated Fair Values of Share-Based Awards (Detail)	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Shares of common stock subject to outstanding options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (in years)	6 years	6 years	6 years	6 years
Expected volatility	71.00%	66.00%	70.72%	68.75%
Risk-free interest rate	2.34%	2.76%	2.43%	2.71%
Expected dividend yield	0.00%	0.00%	0.00%	0.00%
Employee Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (in years)	6 months	6 months	6 months	6 months
Expected volatility	76.66%	105.32%	76.66%	105.32%
Risk-free interest rate	2.51%	1.61%	2.51%	1.61%
Expected dividend yield	0.00%	0.00%	0.00%	0.00%

Stock Incentive Plans - Summa_3

Stock Incentive Plans - Summary of Expense Relating to Employee and Nonemployee Stock-Based Payment Awards from Stock Options and RSUs (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Share based compensation, Total expensed	$ 4,992	$ 2,512	$ 11,045	$ 3,217
Cost of Revenue [Member]
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Share based compensation, Total expensed	508	191	1,280	252
Research and Development Expense [Member]
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Share based compensation, Total expensed	1,441	462	2,273	675
Sales and marketing [Member]
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Share based compensation, Total expensed	940	466	1,671	529
General and administrative [Member]
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Share based compensation, Total expensed	$ 2,103	$ 1,393	$ 5,821	$ 1,761

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Income tax benefit	$ 220	$ 381	$ 826	$ 805
GILTI tax rate					10.50%

Segment Reporting - Additional

Segment Reporting - Additional Information (Detail)	6 Months Ended
	Jun. 30, 2019Segment
Segment Reporting [Abstract]
Number of reportable segments	1

Segment Reporting - Reportable

Segment Reporting - Reportable Revenues by Geographic Regions (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Segment Reporting Information [Line Items]
Revenues	$ 31,454	$ 17,823	$ 57,436	$ 31,876
United States [Member]
Segment Reporting Information [Line Items]
Revenues	28,775	15,407	52,015	26,854
Rest of The World [Member]
Segment Reporting Information [Line Items]
Revenues	723	687	1,512	1,320
Europe [Member]
Segment Reporting Information [Line Items]
Revenues	1,956	1,729	3,909	3,702
Testing Services [Member]
Segment Reporting Information [Line Items]
Revenues	25,677	13,997	47,195	24,601
Testing Services [Member] | United States [Member]
Segment Reporting Information [Line Items]
Revenues	25,499	13,853	46,885	24,313
Testing Services [Member] | Rest of The World [Member]
Segment Reporting Information [Line Items]
Revenues	178	144	310	288
Product [Member]
Segment Reporting Information [Line Items]
Revenues	4,593	3,550	9,026	6,857
Product [Member] | United States [Member]
Segment Reporting Information [Line Items]
Revenues	2,168	1,319	4,000	2,164
Product [Member] | Rest of The World [Member]
Segment Reporting Information [Line Items]
Revenues	519	543	1,177	1,032
Product [Member] | Europe [Member]
Segment Reporting Information [Line Items]
Revenues	1,906	1,688	3,849	3,661
Digital and Other [Member]
Segment Reporting Information [Line Items]
Revenues	1,184	276	1,215	418
Digital and Other [Member] | United States [Member]
Segment Reporting Information [Line Items]
Revenues	1,108	235	1,130	377
Digital and Other [Member] | Rest of The World [Member]
Segment Reporting Information [Line Items]
Revenues	26	0	25	0
Digital and Other [Member] | Europe [Member]
Segment Reporting Information [Line Items]
Revenues	$ 50	$ 41	$ 60	$ 41

Segment Reporting - Long-Lived

Segment Reporting - Long-Lived Assets Consisting of Property and Equipment, Net by Geographic Regions (Detail) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Segment Reporting Information [Line Items]
Long-lived assets	$ 3,508	$ 4,134
United States [Member]
Segment Reporting Information [Line Items]
Long-lived assets	2,712	3,235
Europe [Member]
Segment Reporting Information [Line Items]
Long-lived assets	498	625
Rest of The World [Member]
Segment Reporting Information [Line Items]
Long-lived assets	$ 298	$ 274